life ^. ^ pm lltlirarg Date Due Mnv4.'? .» •, ^i given are as follows: oats 26.16; Fig. 1. — World production of food crops , J.^r.,vr.l i -.^r.- ^ ^^ 1009-1913. wheat 18.72 ; barley, 12.35 ; while in the case of potatoes the crop of the United States is only 6.49 per cent of the world's crop. Home vs Foreign Potato Production. — It is of considera1)le interest in the present study of the potato crop, to compare the ]iroduction of the United States with that of some of the leading Foreign potato-producing countries, in order to study in greater detail the relative position of each with respect to volume of pro- duction. These data, which are assembled in the next table, are rather illuminating in that they show the magnitude of the crop produced in Germany and Eussia, and the relatively small crop grown in the United States. It will also be noted, that while this country occupies fifth position both in acreage and volume of pro- duction, yet it is next to the lowest in acre yield. The data further shows that the potato crop of Germany is almost five times greater than that of the United States for the years mentioned, or, expressed in percentage, our crop is but 21 per cent of tlie German crop. A study of the percentage of the world's crop of potatoes, produced by the countries included in the following table, discloses equally interesting comparisons. Germany's crop represents 30.8 per cent of the total produc- tion; Kussia's 22.9; Austria Hungary 12.1; France 8.9; United States 6.5; Great Britain 4.6; Belgium and the Netherlands each RELATIVE IMPORTANCE OF POTATO CROP about 2 per cent. Another very interesting comparison may be made from these data relative to the average production per acre. Average acreage grown and bushels produced in the leading potato growing countries of Europe and America, 1909-1913 inclusive -^ Country (a) Area in acres Total bushels (b) Average bushels per acre (b) Percentage of World's Crop Germany 8,260,250 11,127,250 4,888,250 3,841,000 3,679,500 1,169,250 414,500 389,e67(=) 715,000C') 657,500 475,750 379,000 301,000 185,667(^) 139,667(») 1,681,959,000 1,251,425,600 662,202,400 489,376,800 354,095,600 254,438,200 110,152,600 107,021,000 92,051,500 60,813,400 77,872,400 63,759,200 48,238,800 40,537,400 32,440,400 203.6 112.5 135.5 127.4 96.2 217.6 265.7 274.6 128.7 92.5 163.7 168.2 160.3 218.3 232.3 30 8 Russia (European) Austria \ 22.9 Hungary/ France 12.1 9.0 United States Great Britain Netherlands 6.5 4.7 2.0 2.0 Spain 1.7 Italy 1.1 1.4 1.2 So. America (>) Switzerland 0.9 07 0.6 t No later European data available. (') (a) Average 1911-191.3. («) (b) Computed from columns 1 and 2. (') (') Argentina and Chile. P) 1911, 1912 and 1913 data. 1910 and 1912 data. 1911, 1912, and 1913 data. 1910, 1911, and 1912 data. Note. All data in columns 1 and 2 from the Yearbook of the U. S. D. A. Ranked on this basis, Belgium leads the list with an average of 274.6 bushels; the Netherlands come next with 365.7; Denmark is third with 232.3 bushels per acre; Switzerland is fourth with 218.3; Great Britain fifth with 217.6, and Germany sixth with 203.6 bushels. The nine remaining countries rank as follows : Sweden 168.2; Canada 163.7; South America 160.3; Austria Hungary 135.5; Spain 128.7; France 127.4; Eussia 112.5; United States 96.2; and Italy 92.5. Relative Importance of the Potato Crop in the United States. — As determined by acreage and value of the crop produced, the potato occupies sixth place among the crops grown in the United States. If, however, it is considered on the basis of a table THE POTATO AS A WORLD CROP gSQ Per cent increase over 1910- 1914 period to o s § O iJ" fiil < It. < > i i 1 1 1 1 S S. 1 1 i i. siSiiigijigs S" -^ ^ " 11 i III 0. J2 i XI ' SI XI-:- 11 iiii it iiii i: 1- =: i- i: :: ^§ -- 23 g| ^?? feS 11 NO w,oo oio coS oS So 2 SS oS So So So ss So ss ss So ss ss a 6 E 6 1 a 1 8 1 .2 RELATIVE IMPORTANCE OF THE POTATO CROP 5 food i)roduct, it undoubtedly is ouly second to that of wheat. The data, as presented in the table {p. 4) show the average annual acreage, production, and farm value of these six leading agricul- tural crops in the United States for the two five-year periods of 1910-1914, and 1915-1919. It is clearly evident from these data that the corn crop is, by all odds, the most important. Its total value is greater than hay and wheat combined, and is some seven times more valuable than the potato crop. In production per acre potatoes easily take the lead, both in bushels and in money value. In comparing the ii""i^""^ money value of a crop, — 1^ — I it is very necessary to take into consideration the actual cost of pro- ducing it. For example, the cost of producing a crop of wheat or oats is necessarily less than that of corn; and, to a — ^ ^"=''"'* much greater extent, C=l Dollars +1,- • X • this IS true m a com- Scale ^i inch 400,000,000 bu. or dollarB. parisOU of the produC- FiG. 2. — Average production in bushels and farm tioU COStS of COm and value in dollars Dec. 1, for 1910-1914. 1915-1919. potatoes. T h e potato crop is a much more expensive one to grow. This increased cost is self-evident to those familiar with potato production. It may be briefly summed up in two words, labor and fertilizer. These two items are the big factors in the growing of potatoes in sections where commercial fertilizers are used. The data in the table illustrates one other point quite as forcibly as that of relative yield and farm values ; it is that of the upward trend of prices of agricultural products during the last five-year period. To the writer, this is one of the most striking lessons presented in the table. With very little variation in acre yields, the value of the crops have, in some cases, more than doubled. Corn, for example, increased over 114 per cent; hay nearly 50 per cent; wheat over 91; cotton almost 100; oats nearly 72, and potatoes over 97 per cent. / 1910 6 THE POTATO AS A WORLD.CROP It is thus apparent that war conditions enhanced the value of agricultural products quite materially. The main object in presenting these data is, however, primarily for the purpose of comparing the relative importance of the potato crop in American agriculture in such a way as to permit of quick comparison with that of the grain crops, corn, wheat, and oats. This is well illustrated in figure 2 which graphically represents the production and value of the corn, wheat, oats, and potato crops during the two five-year periods 1910 to 1914 and 1915 to 1919 (Fig. 2). QUESTIONS ON THE TEXT 1. What is the relative magnitude of the potato when viewed as a world crop? 2. With what other food crops is it compared? 3. Why has the rice crop been omitted? 4. What is the relative importance of rice as compared with wheat? 5. What percentage of the total of these six food crops consists of potatoes ? 6. What crop is next in percentage of production to the potato? 7. Give order of next four crops. 8. What is the excess production of potatoes over corn and wheat? 9. What percentage of the world's potato crop does the United States produce? 10. What percentage of the world's corn crop does the United States produce? 11. What is the respective magnitude of the other four crops as expressed in percentages? 12. Wliat position does the United States occupy with other coiuitries as regards the magnitude of her potato crop? 13. What countries exceed the United States in potato production? 14. Name the six leading countries in the order of their importance from the standpoint of production? 15. Give the percentage that each of these six countries produce. 16. What country produces the largest average yield per acre? 17. Give the six leading countries based on acreage production. IS. What position does the United States occupy in yield per acre? 19. What is the relative importance, based on monej^ value, of the potato crop in the United States, as compared with corn, hay, wheat, cotton and oats? QUESTIONS SUGGESTED BY THE TEXT 1. What is the annual yield of potatoes in your county and state? 2. Compare the yields of potatoes and six other important crops in your county and state? CHAPTEE II POTATO PRODUCTION IN NORTH AMERICA United States Production. — While it has been shown in the preceding chapter that the potato crop of the United States is hardly more than a drop in the bucket, as it were, of the world's crop, it is, nevertheless, a very important agricultural crop in cer- tain sections of the United States and Canada. Owing to rather unreliable and fragmentary data concerning potato production in Mexico, no attempt has been made to include it in the present dis- cussion. The data presented in the tables on pages 8 and 9 give the average acreage and production for two five-year periods, 1913- 1916, and 1915-1919, inclusive. The main object in presenting these two sets of data is that of affording an opportunity to observe the changes brought about in some sections, as a result of war con- ditions, in the acreage devoted to potato production. One of the interesting features of these changes is that of the rank or relative position of the various states with respect to the magnitude of their production. A study of the table shows that only three of the six largest producing states maintained their relative positions during the two five-year periods. These states were Nev/ York, Wisconsin, and Pennsylvania. Michigan drops from second to fourth place, Maine from fourth to fifth, while Minnesota passes from fifth to second position. In the second group of six states the position of every one is slightly changed; for example, Virginia moves into seventh place and Ohio drops from seventh to ninth; while Cali- fornia rises from eleventh to eighth position, and Iowa drops from ninth to fourteenth place. While these changes in rank are in- teresting to note, they are by no means vital to the industry, except as they illustrate responses to economic or climatic condi- tions, the first of which reacts in a larger or smaller acreage accord- ing as to whether the previous crop brought a high or a low price ; and the second, in the production of a larger or smaller number of bushels per given area, as is evidenced by a comparison of the average yield per acre. The climatic factor exerts a much greater influence on the total production of any given section than does the ordinary fluctuation in acreage, due to economic conditions. There are, of course, exceptions to the preceding statement, as was evi- denced by the very large increase in the 1918 acreage in a number of the Southern states, particularly in Florida, due to the exceed- ingly high price received for the 1917 crop. 7 Average acreage and production of ■potatoes by States for the 1912-1916, inclusive 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 New York Michigan Wisconsin Maine Minnesota Pennsylvania. . Ohio Virginia Iowa New Jersey . . . CaUfornia lUinois Washington . . . Nebraska Colorado Oregon North Dakota. Indiana Missouri South Dakota . Montana Idaho Kansas West Virginia . Kentucky Maryland Vermont Utah Massachusetts. North Carolina. . Texas Connecticut Oklahoma New Hampshire . Nevada Wyoming Arkansas Louisiana Alabama Florida Delaware Mississippi Georgia South Carohna. New Mexico ... Rhode Island Arizona Number of acres 352,400 347,800 295,600 133,600 271,000 270,000 157,800 115,400 141,200 91,200 74,800 127,400 61,600 113,800 63,600 53,400 67,400 77,200 89,600 63,600 37,600 31,600 71,200 48,200 50,200 42,200 24,600 19,800 26,200 36,600 32,400 44,600 23,400 32,400 16,400 12,400 14,600 25,600 24,400 18,200 12,600 10,800 11,800 13,600 10,400 8,600 5,000 1,000 Number of bushels 32,485,000 30,139,800 28,865,400 28,560,800 28,223,000 23,909,000 12,833,600 11,833,300 11,247,600 10,252,400 9,859,400 9,627,400 8,884,600 8,751,800 7,466,000 7,069,600 6,712,200 6,054,800 5,881,000 5,794,000 5,449,000 5,015,000 4,797,400 4,382,800 4,078,600 3,934,000 3,236,600 3,203,000 3,159,000 2,680,000 2,609,200 2,606,000 2,479,800 2,135,400 2,095,400 2,076,400 1,946,000 1,839,000 1,588,600 1,509,800 1,009,000 976,400 952,000 925,600 820,000 805,600 592,000 104,000 Averages and totali- 3,674,800 361,450,200 Average acreage and production of potatoes by States for the years 1915-1919, inclusive Number of acres Number of bushels Average bushels per acre New York Minnesota Wisconsin Michigan Maine Pennsylvania Virginia California Ohio New Jersey Illinois Colorado Nebraska Iowa Washington Missouri North Dakota South Dakota Indiana Oregon Kentucky West Virginia Montana Idaho Kansas Maryland North Carohna .... Tennessee Massachusetts Wyoming Utah Vermont Alabama Texas Arkansas Oklahoma Connecticut New Hampshire . . . Louisiana Florida Nevada South Carolina .... Georgia Mississippi Delaware New Mexico Rhode Island Arizona Averages and totals 363,600 295,400 299,800 343,800 126,200 280,400 139,200 87,200 152,600 100,600 143,200 74,800 119,600 123,200 64,200 102,800 85,400 79,600 89,800 54,600 63,400 53,000 46,400 32,800 73,400 51,000 48,400 44,400 31,200 26,000 20,000 26,000 37,000 48,000 37,600 39,800 24,400 18,800 31,600 22,200 10,600 19,200 19,200 15,600 11,400 9,600 5,000 3.200 31,843,400 27,894,000 27,238,000 25,892,000 23,309,600 23,226,000 15,052,000 12,032,400 11,037,200 10,991,200 10,838,000 10,747,000 9,688,200 8,940,200 8,715,200 7,793,400 6,564,600 6,491,000 6,377,000 6,320,000 5,585,400 5,262,800 5,181,000 5,064,800 4,943,400 4,752,600 4,397,000 3,525,600 3,451,400 3,398,000 3,288,800 2,986,600 2,934,400 2,917,200 2,709,200 2,496,200 2,279,000 2,202,400 2,119,600 1,933,800 1,922,400 1,740,200 1,351,200 1,250,000 1,027,400 877,400 534,000 281.000 87.6 94.4 90.9 75.3 184.7 82.8 108.1 137.9 72.3 109.2 75.7 143.7 81.0 72.5 135.8 75.8 76.9 81.5 71.0 115.8 88.1 99.3 111.7 154.4 67.3 93.2 90.8 79.4 110.6 130.7 164.4 114.9 79.3 60.8 72.1 62.7 93.4 117.2 67.1 87.1 181.4 90.6 70.4 80.4 90.1 91.4 106.8 87.8 3,995,200 371,403,200 92.9 10 POTATO PRODUCTION IN NORTH AMERICA A detailed study of the annual acreage, production, average yield per acre, and price per bushel of potatoes by states during the years 1915-1919, (see table in Appendix) shows tliat, with but few exceptions, the acreage increase in 1917 was quite marked in the North, due to tlie high prices received for the 1916 crop; whereas, in the South the greatest increase in acreage occurred in 1918, following, as has been previously mentioned, the high prices re- ceived for the Southern 1917 crop. If we neglect the years 1917 and 1918 and study the acreage of the three previous years, it will be noted that there is comparatively little fluctuation in the total acreage planted. On the other hand, it is at once apparent from the data presented that there is comparatively little relation between acreage and yield. This statement can, perhaps, be best illus- trated by noting the variation in yield between Iowa's 1915 and 1916 crops, in which the acreage variation is less than 5 per cent., while that of the yield is nearly 160 per cent. Further evidence of fluctuating variations in yield may be noted by a comparison of the New York, Michigan, and Wisconsin data, in which the varia- tion in acreage between the years 1915 and 1919 in New York was less than 3.3 per cent, while the variation in yield was nearly 80 per cent. The Michigan data show the widest variation in yield between the years 1916 and 1917 in which the acreage fluc- tuation was a little over 1.8 per cent while the yield variation was nearly 134 per cent. In Wisconsin, the variation in 1916 and 1917 potato acreage was a little less than 6 per cent, while the increase in yield was nearly 157 per cent. The chief interest in these data lies not so much in the magni- tude of production of each state, as it does in the average yield per acre. This, it would seem, is a better indication of the relative adaptability and economic value of a crop, than is that of its magnitude of production in any given state. Considered on this basis, Maine leads with 187.1 bushels per acre; Nevada, second, with 183.1; Utah, third, with 164.4; and Idaho fourth, with 154-1 bushels. In each of these states except the first, most of the potatoes are grown on irrigated land. The lowest yielding states are those of Texas, Oklahoma, Louisiana, Kansas, and Georgia. In most of these states, potatoes are grown largely for the early market; consequently they are usually harvested before they have attained their full growth, and in consequence thereof, do not give the yields that they otherwise would if allowed to reach full maturity. A SUMMARY 11 Potato Production in Canada. — While the production of pota- toes in Canada has not assumed the magnitude of that of the United States as judged in terms of bushels, it more than compares favorably with it, if the comparison is made on the basis of popula- tion. On such a basis, the 1918 Canadian crop of 105,579,000 bushels would call for a production by the United States of about 1,302,141,000 or nearly four times as much as is now being grown. It will be seen, therefore, that much depends upon the kind of comparison that one attempts to make, as to whether a crop seems relatively small or relatively large. iVll of the nine provinces which constitute the Dominion of Canada produce considerable quantities of potatoes as compared with their population. For the purpose of comparison, the acreage, production and average price per bushel for the years 1913 to 1918 have been tabulated (see Appendix). A study of this data shows quite a variation in yields from year to year which, for the most part, are attributable to unfavorable or favorable climatic influences. Total Production and Yield per Acre hy Provinces. — A further study of the data shows that they stand in production in the following order, the total average production being given : Quebec 2 1,076, .571 bushels, 144. .5 bush, per acre. Ontario 18,352,286 bushels, 120.1 bush, per acre. New Brunswick 8,278,514 bushels, 186.2 bush, per acre. Nova Scotia 7,255,786 bushels, 199.7 bush, per acre. Saskatchewan 6,211,843 bushels, 154.3 bush, per acre. Prince Edward Island 5,885,329 bushels, 182.7 bush, per acre. Manitoba 4,893,556 bushels, 159.6 bush, per acre. Alberta 4,891,914 bushels, 157.9 bush, per acre. British Columbia 3,221,857 bushels, 207.6 bush, per acre. The data on the production of Canada for the years 1913 to 1918, as shown in the table, indicate the same variation in yields as in the United States, with the additional feature of a very large increase both in acreage and production in 1918. Acreage and Yields hy Years. — The next table shows the results arranged by years from 1913 to 1918 inclusive. * A Summary of the data relative to production indicates that the total average yield for the United States and Canada, exclusive of Newfoundland, for the past five seasons, 1914 to 1918 inclusive, is 459,169,740 bushels. If we add to this about one and one-half million bushels from Newfoundland and a million bushels from Mexico, it makes the average total production of North America *Data taken from Canada Census and Statistic monthly. 12 POTATO PRODUCTION IN NORTH AMERICA ai)])roximately 461,()fi!),740 bushels or a little over one-fourtli that of Germany. If, on the other hand, we regard the last two seasons' crops as more nearly indicative of what can be marketed advanta- geously in the North American continent, we need to add about fifty million more bushels to the figures previously submitted, making a grand total of over 510 and one-half million bushels. Total acreage and production of potatoes in Canada for the years 1912-1!) IS Year A.creage Total Av. bus. Av. price Yield bus. per acre. per bus. 1912 484,000 84,885.000 175.4 $0.44 1913 473.500 78,544,000 165.9 .49 1914 475,900 85,672,000 180.0 .49 1915 479,000 02,604,000 130.8 .57 1916 473,000 63,297.000 136.2 .81 1917 656,958 79,892,000 121.5 1.01 1918 735,192 105,579,700 143.5 .98 Average 539,650 80,067,671 150.5 .684 One of the most significant features of potato production in the United States is that, during the past five seasons 1915-1919, the 21 Northern States produced over two-thirds (68.8 per cent) of the total crop, the remaining third being about equally divided between the 11 Far West States and the 16 Southern States. United States Crop, 370,493,800 bushels. 21 Northern States 258,006,200 bushels, 68.8 per cent. 11 Far West States 56,238.200 bushels, 15.2 per cent. 16 Southern States 56,249,400 bushels, 16.0 per cent. As larger areas in the far west states are brought under irrigation, increased potato production may be expected, but the l)ulk of the crop must, of necessity, be produced -within a reasonable distance of the consuming public. QUESTIONS ON THE TEXT 1. Of what importance is the potato as an aj^rieultural crop in North America ? 2. According to the data presented, what states lead in potato production? 3. Does the second period of live years show any material change in the relative rank of the leading .states? 4. What two factors influence potato production in any given section? 5. Which of the two factors is the greater? 6. What lessons are to be derived from the average yields per acre for the difi'erent states? 7. Name some of the highest yielding states? QUESTIONS SUGGESTED BY THE TEXT 13 8. Name some of the lowest yielding ones? 9. How does the Canadian crop compare in per capita production with that of the United States? 10. Which of the nine Canadian provinces shows the largest average acre production? 11. How does the acreage production of the provinces compare with that of individual states in the United States? 12. \\]mt is the approximate extent of the North American potato crop? 13. How does it compare with that of Germany? 14. What percentage of the potato crop of the United States do the 21 Northern States produce? 15. How much do the 11 Western States produce? 16. How much do the 16 Southern States produce? 17. What limits a large expansion of potato production in the West? QUESTIONS SUGGESTED BY THE TEXT 1. Have the yields and acreages in your state been increasing or de- creasing ? 2. Give the probable factors influencing this. 3. Are the yields per acre in your state changing materially? If so, why? 4. Compare the yields of potatoes in your state with six other food crops of the state. 5. Compare the potato production in your state with other states nearest to it in rank. CHAPTEK III LEADING ENVIRONMENTAL INFLUENCES IN POTATO CULTURE.— SOIL, TEMPERATURE, AND MOISTURE The three leading environmental influences which are most closely associated with the ])roduction of a profitable crop of pota- toes are those of soil, temperature, and moisture. These factors, while not so completely under the control of the grower as those of plant food, tillage, and spraying, are, nevertheless, under intelli- gent management capable of a considerable degree of modification. The first requisite on the part of the grower in the profitable production of any crop is a thorough understanding of its require- ments in the way of soil, temperature, and moisture. It is neces- sary to know whether it is a heat or a cold, a moisture or a drought loving plant, and the character of soil best suited to its develop- ment. In the case of the potato, it is well known that it is a cool loving plant; that it requires a reasonable supply of moisture for its best development, and that, while more or less cosmopolitan in its soil requirements, it nevertheless thrives best on sandy, gravelly, or shaly loam soils. The successful production of potatoes may then be said to be confined to regions in which the mean temperature during the growing season is relatively low; where the normal rainfall during the same ])eriod is sufficient to insure a steady growth of the plants, or where the land can be irrigated and where the soil is of such a character as to provide the most suitable conditions for the development of both plants and tubers. To a certain extent, therefore, these requirements confine the production of the late potatoes, at least, to the northern portions of the United States. Soil Requirements. — While the potato plant is rather cos- mopolitan in its soil requirements, it nevertheless succeeds much better on certain types of soils than on others. Generally speaking, sandy, gravelly or shaly loam soils are conceded to be the best, while a heavy sticky clay, or a very light sandy soil is admittedly the poorest and should always be avoided when possible. Potatoes may be successfully grown on muck or peat soils, and in certain sections of the United States quite a potato industry has been developed on these types of soil. As a rule, however, potatoes produced on 14 TEMPERATURE CONDITIONS 15 muck or peat soils are less rich in starch than those grown on a gravelly or sandy loam soil. To be entirely suited to the potato crop a soil must be loose and friable, well supplied with organic matter, deep, well drained and with sufficient moisture, either from natural or artificial sources, to insure the development of a good crop. Furthermore, as is shown in the discussion of temperature, soil which is naturally cool is the more desirable for potato culture. The type of soil known as the Caribou loam, which is found in Aroostook County, Maine, is almost ideal in this respect. This is a chocolate brown colored soil, abundantly supplied with -small decomposing fragments of shale rock with which it is underlaid. This shale formation, which generally lies in a vertical or partially horizontal position, is more or less regularly seamed, affording almost^ perfect drainage through its crevices, while during dry weather it serves as a source of moisture supply to the soil above it. The question of soil moisture is not such a vital one in the irrigated regions of the West, as is the question of drainage and suitability of the physical texture and composition of the soil to the potato plant and to irrigation. Land Elevation. — The elevation of the land may and does very materially influence its desirability. The choice of simi- larly located lands with respect to shipping facilities should always be made in favor of that having the greatest altitude, provided such altitude is not sufficient to preclude the successful growth of the potato. For example in the New England States, an eleva- tion of 2000 to 2500 feet is equal to one of 6000 or 7000 feet in the West, so far as seasonal and climatic conditions are concerned, and this must, of necessity, be taken into consideration in the selection of a potato farm. Temperature Conditions. — In view of the fact that tempera- ture plays a very important role in potato production, and that it is a factor over which the grower can exercise very little control, it is essential that the temperature conditions of any given locality should he very carefully studied before engaging very extensively in the growing of this crop. In this connection, Smith^ says : "In the United States the potato has made its greatest development in the cooler sections of the country, where the mean annual temperature is between 40 and 50 degrees F. and where the mean temperature in July is not over 70 degrees. Further, the greatest yields of potatoes per acre are in those states where the mean annual temperature is be^ow 45, and where the mean of the warmest month is not far from 65." IG INFLUENCES IN POTATO CULTURE He further assumes the thermal constant of the potato to be 43 degrees F. and that the sum of the average daily degrees of lieat above 43 represents the effective growing temperature for tliis crop iiecessary to bring it to maturity. In Ohio, Smith found that while cool weather is more favorable to tuber production than warm, in each month considered, the temperature of either May, June, August, September, or October alone, has very sliglit influence as compared with July upon the Fio. 3. — Environmental influence on form of tuber of Green Mountain. Tubers 1, 2, 5, and 6, very much modified; 3 and 4 true to type. Modification due to heat and drouth. Tubera produced from the same strain of seed. potato yield. Also that the temperature of June, and July, July and August, or June, July and August combined had just about the same effect as that for July alone. It is believed that Smith's statement should be qualified by a further one, in which it is clearly set forth that if the potato crop is planted in Ohio approximately at a given date, the critical temperature period in the gro\\'th of the plants, so far as its influence upon yield is concerned, is during the month of July. The critical temperature period in the growth of the potato plant, insofar as it exercises a distinctly favorable or unfavorable influence on yield, is during the time in which it is developing its tubers. In regions in which the growing season is sufficiently long so that the planting date may vary from four to six or more weeks, it is quite possible, with a thorough knowledge of the average normal temperature conditions that may be expected in each growing month, to so govern the time of planting as to subject the plants to the most unfavorable temperature conditions at the period in their growth when the least injury would be TEMPERATURE CONDITIONS 17 incurred. For exam])le, in Western New York it is customary to delay the planting of the late croj) of j^otatoes until the early j)art of June, and sometimes even to July 1. This practice is, in all I)robability, not the direct result of any careful study of the temperature conditions prevailing in any given month, but due rather to the fact that the later planting usually gave better yields. A four years' experience in growing potatoes near Eochester, New York, inclines the writer to believe that August, rather than July, Fig. 4. — Enviroiiineiital iiiflucuce on form of tuber of Irish Cobbler. Tubers 1 and 2 very much modified, 3 and 4 true to type. Modification dvie to heat and drought. Sources of seed identical. is the critical month in that section; August rather than July be- ing the critical month simply from the fact that the crop is ])lanted later, and is setting its tubers during this period. Were the crop planted a month earlier, July would doubtless represent the critical period. There can be no question but that high air and soil temperatures are incompatible with a healthy and normal growth of the potato plant; and if extremely high temperatures prevail when the plants should normally set and develop their tubers, the yield will be materially reduced and the tubers visibly modified (Figs. 3-6). For this reason, the chief potato producing regions of the United States must, of necessit}-, be confined to the northern and north-eastern tier of states. In the South where the potato is, in some sections, grown extensively as an early truck crop, early planting provides temperature conditions which in the main are comparable v/ith those of the North. In this connection Smith says (p. 224) "that whether the date of planting is February 2 18 INFLUENCES IN POTATO CULTURE in northern Georgia, or May 1 in the northern })ortion of the United States, the seasonal rise has brought the temperature close to 45 degrees F." It should be clearly borne in mind that while the amount of injury sustained ])y the potato plant is, as has been said, very largely dependent on whether it occurs during the critical period in the development of the plant, there is another element Avhich may very materially increase or minimize high temperature injury Ficj. 5. — Enviroiiiiieiital influence on form of tuber of Carman No. 3 Tubers 1 anil 2 very much modified, 3 and 4 true to type. Modification due to heat and drought. Source of seed identical. to the crop, and that is the presence or absence of a sufficient amount of moisture in the soil. If high temperatures are accom- panied by a low soil moisture content during the critical period in the life of the plant, and these conditions prevail for any con- siderable period, the injury sustained will be very much greater than when a sufficient amount of soil moisture is present. In the first place, high temperatures accompanied by a drought usually result in a large amount of what the physiologist recognizes as tip-burn of the foliage, brought about through a more rapid trans- piration of moisture through the leaves of the potato plant than its roots can supply, owing to lack of available moisture in the soil. As a result of this unbalanced ratio between moisture loss and moisture supply, the cells of the tips and margins of the growing leaves soon collapse and dry up, giving the ]ilant the appearance of having been scorched by fire. This type of injury may occur SOIL TEMPERATURES 19 prior to the formation of tubers, but is far more likely to occur during or after their formation. The presence of a sufficient amount of soil moisture exercises a favorable influence on the soil temperature during protracted heat periods, by reason of the cooling effect exerted through the evaporation of moisture from both the soil and the plants grow- ing thereon. Soil temperatures are believed to play a by no means Fig. 6. — Environmental influence on form of tuber of Rural New Yorker No. 2. Tubers 1 and 2 very much modified, 3 and 4 true to type. Modification due to heat and drouth. Source of seed identical. unimportant role in the determination of potato yields. Of course, it must be conceded that high soil temperatures cannot obtain except when a high air temperature prevails. In some greenhouse studies recently made by Pitch^ the effect of tempera- ture and moisture upon the health and vigor of potato plants was noted. The soil temperatures employed were 50, 65, 80, and 90 degrees F., and the moisture content of the soil approximately 10 to 20 per cent for all the period; 20 per cent for 75 days, then 30 for 5 days ; and 40 for the fourth lot, which, however, the author says, he did not dare to use during the main growing period, be- lieving that it would cripple the plants. Potatoes maintained at 95 degrees F. were all killed before coming up. In regard to the relation of temperature to moisture Fitch found a distinct correlation, that is, the higher the temperature and the moisture the greater the amount of injury to the plant. Plants grown in soil having an approximate moisture content of 10 per cent did not show any bad effects from being subjected to 80 degrees F. 20 INFLUENCES IN POTATO CULTURE Moisture. — The important rule that water plays in the gro^^i;h of both plants and animals has long been recognized and has very justly received a great deal of attention. Several years ago Arthur ^ road a paper before the memliers of the American Carnation Society, entitled "Moisture, the Plant's Greatest Requirement" in which the following statements were made (p. 67) : "If we remembei- that the chief growth of the plant takes place in the parts where the largest amount of water occurs, we shall be reasonably safe in inferring that 'water is a very essential factor in growth. It has been ascertained, in fact, that the tissues must not only be saturated with water, but they must be super-saturated, that is, contain so much water that every cell is distended with the pressure, before growth will proceed." It is well known that the food elements in the soil necessary to the proper development of the plant must first be brought into solution by tlie soil moisture before they can be taken up by the delicate root-hairs of the j^lant. Furthermore, it is known that water is, also, just as essential in transporting the liquefied food elements from root to leaf, and the elaborated food from the leaves to other parts of the plant. Hence it is that every metabolic pro- cess of the plant is concerned with moisture. At the same time, it must be remembered that while an abundance of water is desiralile, an over-abundance may be, and usually is, harmful. Moisture Bequirements. — The actual amount of water neces- sary to the development of one pound of dry matter in the growing plant has been rather carefully studied by the plant physicist. King* of Wisconsin, found that it required from 301 to 576 pounds of water to produce one pound of dried potato. Briggs and Shantz" found that it required, nnder semi-arid conditions in Colorado, 636 l)Ounds of water to produce one pound of dry matter. Widtsoe*' in a somewhat different manner ascertained that, under irrigation conditions as they obtain in Utah, the evapo-transpiration ratio between moisture and dry matter varied in direct ])roportion to the number of acre inches of Avater applied to the crop. When 5 acre inches were applied, the ratio was 1 to 1136; while with 60 acre inches it was 1 to 3292. Usually measurements of water required to produce one pound . of dry matter are based upon the amount of water actually tran- spired by the leaves and stems of the plant and do not therefore represent the moisture loss due to evaporation from the soil itself Smith says, {I.e. p. 225) : RAINFALL 21 "This water requirement is sometimes called the 'transpiration ratio' It does not take into account the water from !a rainfall that may run off from the surface of the ground or what is lost by seepage or sur- face evaporation." Widtsoe's data takes both of these factors into consideration. RainfalL — In determining the suitability of any given region for potato production on the basis of annual rainfall it is highly essential that careful consideration should be given to the distri- bution of the season's rainfall. The average precipitation during the growing season is the real determining factor. In the best potato growing regions the average total rainfall, during the period between planting and harvesting late potatoes, varies from 12 to nearly 18 inches. But, even where the heavier precipitation occurs, it might be so unevenly distributed as to make it impossible to produce heavy yields. A goodly supply of moisture is essential to a quick and healthy growth of the plant, and, when the tubers are set, to promote a steady and uniform gro^vth. Heavy pre- cipitations during the latter part of the growing season are not desirable, as they favor the development of late blight and rot, and also make it difficult to harvest the crop in a satisfactory condition. Much may be done by the grower to conserve the soil moisture by good cultivation and the maintaining of an earth mulch. This subject will l)e more fully discussed under tillage. QUESTIONS ON THE TEXT 1. What are the three leading environmental factors in potato culture? 2. To what extent are these three factors controllable by man? 3. To what regions is the successful production of potatoes usually confined ? 4. What are the soil requirements for potatoes? 5. Describe the Caribou loam soil. 6. Of what importance is land elevation? 7. What does Smith say about temperature influence? 8. According to Smith, which is the most critical period in the life of the potato plant so far as tuber production is concerned? fl. If any, what qualification would you make? 10. What happens to the potato plant when high air and soil temperatures are accompanied by a low soil moisture content? 11. Explain physiological collapse of cell structure of the leaf? 12. What eft'ect has high soil temperature on tuber production? Cite Fitch's experiments. 1.3. Of what importance is moisture to the plant? 14. Give Arthur's statement regarding cell saturation and cell growth, l.'i. What amount of water did King, Briggs, Shantz, and Widtsoe find was necessary to produce a pound of dry matter? 16. In determining the suitability of any given region to potato production based on its rainfall, what factors should be considered? 22 INFLUENCES IN POTATO CULTURE QUESTIONS SUGGESTED BY THE TEXT 1. To what extent is the soil of your region considered suitable fur potato growing? 2. What bad effects of summer heat are noticed Ijy your local growers? 3. In what months, if any, is the local rainfall "likely to be deficient? 4. Find specimens, if possible, showing results similar to those shown in the figures of this chapter. References Cited 1. Arthue, J. C. 1898. ]VI|0isture, the plant's greatest requirement. I'roc. tSeventh Ann. Meeting Am. Carnation Soc: 65-70, Feb. 1898. 2. Briggs, L. J. and H. L. Shantz. 1914. Relative water requirements of plants, v. ti. Dept. Agr. Jour. Agr. lies. 3: 1-04, 7 pis. 2 figs. 1914. 3. Fitch, C. L. 1915. Studies of health in potatoes. Col. low the land intended for the potato crop in the fall, except in Fig. 8. — Plowing a clover sod with a pair of horses. the case of soil that is apt to wash badly during the winter rains and snows. The plowing of the land varies somewhat according to whether the previous crop was alfalfa or clover. Alfalfa Sod. — The usual practice in handling an alfalfa sod is to crown it early in the autumn. The process of crowning con- sists in plowing the sod as lightly as possible, three to four inches is sufficient, and allowing it to lie exposed to the sun, rain, snow and frost during the winter months. The object of early crowning of the sod is to furnish favorable conditions for the drying uj) of the crowns of tlie plants. This process is materially aided by repeated disking of the crowned land in the autumn. In the spring, CLOVER SOD 25 this land should be plowed to a depth of from 9 to 10 or more inches. The above method for preparing alfalfa land for a potato crop is the one most generally practised, but there are a few growers who prefer spring plowing, after the alfalfa has attained a height of from 8 to 12 inches. When this practice is followed, only one plowing is made and this one as deep as it is possible to do conveniently. Clover Sod. — It is the general custom, where a clover sod is to be turned under, to plow the land in the fall. At this time it is ^ _^^i KsAfe Fig. 9. — The use of the plank drag is the final step in the preparation of the potato- seed bed. Where the ground is a Uttle cloddy or the surface somewhat uneven, the grower will be well repaid for the extra labor involved. (Courtesy of Daniel Dean, Nichols, N. Y.) always plowed to its full depth, viz., 8 to 10 or more inches, depend- ing on the depth of the surface soil and the character of the sub-soil (Figs. 7-9). A good rule to follow is that of turning up from a half inch to one inch of sub-soil at each plowing when the surface soil is too shallow. In regions where the planting is delayed until the first to the fifteenth of June, and on lands that have a tendency to wash, it may be desirable as in the special case of alfalfa sod, to plow as late in the spring as it is possible, in order to turn under a goodly mass of the succulent leaves and stems of the clover plant. But whether plowing is done in the fall or the spring, it should be thoroughly done, and every effort should be made to conserve the moisture. Fall-plowed land, if not to be replowed in the spring, should be disked and harrowed as early as possible in the spring 26 THE SOIL AND ITS PREPARATION and then kept friable until the crop is planted. Spring-plowed land should be disked as plowed and kept mellow. Preparation of the Seed Bed. — No expense should be spared in preparing the seed bed. Tlie deeper it is prepared and the more finely it is pulverized, the more suitable it is for the production of a large yield. The choice of implements in fitting the land is, to some extent, a matter of personal preference. A heavy sod, if it has been well plowed, can probably be most quickly and satis- factorily put in shape for the crop by the use of the cutaway disk followed by a smoothing harrow. Some prefer the plain disk to the cutaway while still others like the Acme harrow. The latter harrow is especially valuable on a sod that tears up badly, as this imple- ment slices rather than tears the sod apart. Get the land in as finely divided a condition as possible, as it is much easier to do it before planting than it is afterwards. If the land is lumpy, roll it with a heavy roller or clod-crusher and then harrow it, or else run a plank drag over it until the surface is smooth (Fig. 9). The old adage that " a stitch in time saves nine '' is quite applicable to the proper preparation of the land. QUESTIONS ON THE TEXT 1. What are some of the factors to be considered in the selection of a suitable soil for potatoes? 2. Of what importance is humus to the soil? 3. What crop should precede a potato crop? 4. When should the land be plowed? 5. How should an alfalfa sod be handled? 6. How would you handle a clover sod? 7. Where late planting is practised what variation in the plowing of the land is suggested? 8. What are the determining factors as to fall or spring plowing? 9. How would you proceed to handle fall-plowed land in the spring? 10. How would you handle spring-plowed land? QUESTIONS SUGGESTED BY THE TEXT 1. What types of soil are used for potato growing in your region? 2. What soils have you that are not suitable for potato growing? Why? 3. What crops are grown preceding potatoes in your region? 4. What is the chief source of organic matter for local crops of potatoes? 5. How is the soil usually prepared by local growers? 6. Is spring plowing or fall plowing usually practised by local growers? Why ? CHAPTER V FOOD REQUIREMENTS OF THE POTATO CROP AND HOW SUPPLIED A well balanced and ample food supply is important in the production of any crop if profitable yields are to be secured. This is particularly true with respect to crops requiring a considerable expenditure of money and labor in producing and marketing them. The problem confronting the grower is that of supplying the necessary food elements for the production of a maximum crop with the least expenditure of money and effort. It is, therefore, essential to have somewhat definite information as to what these food requirements actually are, if they are to be intelli- gently supplied. Chemical Elements in Plants. — Notwithstanding the fact tliat there are a great many thousands of different kinds of plants growing on the earth's surface, and that among these there is a great diversity in form and in color of foliage and flower, com- j)aratively few chemical elements are drawn upon to produce them. Of the eighty or more known chemical elements it is claimed by the chemist that only fourteen of this number are commonly found in plants. These fourteen elements, according to Van Slyke^, are calcium, carbon, chlorine, hydrogen, iron, magnesium, manganese, nitrogen, oxygen, phosphorus, potassium, silicon, sodium and sul- pliur. Fortunately most soils are sufficiently well supplied with all but four of these elements, viz. nitrogen, phosphorus, potassium and calcium. The first three of these elements are generally con- sidered the essential ones as calcium is more generally present in soils at least in suffiicient amount for the plant's needs than are the other three. However, there are many soils that are directly benefited, so far as their crop productive power is concerned, by an application of calcium. On the other hand not all soils require nitrogen, phosphorus and potash. Take, for example, the soils of the Avestern portion of the United States, particularly the Inter- Mountain section, where it has been found that most of them are generally well supplied with both phosphorus and potash, but are wofully deficient in nitrogen, and especially in organic matter. In still other sections it has been found that there is, for the present at least, a sufficient supply of nitrogen, phosphorus and potash to 27 28 FOOD REQUIREMENTS— HOW SUPPLIED ]»ro(luce a satisfactory cTop. Generally speaking, the soils of the northeastern portion of the United >States are benefited by an application of these chemical elements. It is apparent, therefore, that one must study his own soil requirements in order to deter- mine whether they are lacking in any of the elements mentioned. It is also rather essential to any intelligent application of plant food to know what amount of nitrogen, phosphorus and potash a 200-bushel-acre potato crop removes from the soil. Relative Amoimts of Nitrogen, Phosphoric Acid, and Potash Removed hy a 2f)f)-hitshcl-pcr-(icre Crop of Potatoes. Source of data Nitrogen Phos- phoric Acid Potash Woods, C. D. and Bartlett, J. M.: Main Sta. Bui. r>7, 1899 Van Slyke, L. L.: Fertilizers and Crops, p. 163, 1915 Voorhees E B ■ Fertilizers p 215 1903 lbs. 37.0 42.0 27.0 54.0 53.3 42.66 lbs. 10.0 18.0 12.0 20.4 20.0 17.28 lbs. 5S.0 GO.O 00.0 Fraser S • The Potato p 54 1905 52.7 Grubb. E. H. and Guilford, W. S.: The Potato, p., 211, 1912 Average amount removed 53.3 56.8 These amounts removed could be supplied with about 270 pounds of nitrate of soda, 108 pounds of a 16 per cent acid phosphate, and about 110 pounds of muriate of potash. As a matter of fact, however, it is necessary to apply an excess of plant food in order to make good the losses that are almost certain to occur through surface washing, leaching, or through combination with inorganic substances present in the soil which may result in the formation of an insolul)le compound. In any case, it is always advisable to supply from 50 to 75 per cent more plant food to the soil than the crop is likely to remove, in order to provide for the various contingencies mentioned. The first consideration in the enrichment of a soil for the production of potatoes, after one has a thorough knowledge of its requirements, is that of the materials available for this ])urpose, their cost, and their economy of use. Outside of the mineral ele- ments naturally contained in all soils there are three general sources of plant food of wliich the grower may avail himself in the enrichment of the soil. These three sources are: (1) green manuring or the turning under of growing crops, (2) farm manures, (3) commercial fertilizers. Green Manuring. — The first of these three sources of plant GREEN MANURING 29 food is available to every grower who is willing to take the trouble of growing a crop to be turned under. Those crops which are most valuable for this purpose are tlie well known members of the pea family, or legumes as they are more generally called. The alfalfa, clovers, peas, beans, cowpeas, soy beans, velvet beans, tre- foils, and beggar weeds are included in this group. Each of these members has its own peculiar value depending on the soil and the Approximate Amounts of Plant Food Constituents in one Legume Crop. Yield per Per cent. Phosphoric Potash Crop acre lbs. of water Nitrogen Acid (PiOs) (K2O) green mattei Alfalfa 20,000 75 120 lbs. 30 lbs. 160 lbs. Clover, alf^ike l(i,000 82 80 lbs. 19 lbs. 48 lbs. Clover, crimson 16,000 82 72 lbs. 19 lbs. 64 lbs. Clover, mammoth 20,000 80 100 lbs. 24 lbs. 80 lbs. Clover, red 12,000 80 66 lbs. 16 lbs. 60 lbs. Clover, white 8,000 81 40 lbs. 16 lbs. 24 lbs. Clover, sweet 20,000 80 110 lbs. 30 lbs. 100 lbs. Field pea 10,000 82 50 lbs. 15 lbs. 50 lbs. Cowpeas 12,000 84 54 lbs. 14 lbs. 54 lbs. Soybean 10,000 1 -y 50 lbs. 15 lbs. 60 lbs. Velvet bean 20,000 7') 110 lbs. 30 lbs. 110 lbs. Vetch 10,000 84 50 lbs. 10 lbs. 45 lbs. climatic conditions under which it must be grown. Of the non- leguminous plants, rye, crab-grass and buckwheat are probably the most commonly employed. Considerable humus and plant food is added to the soil for an ensuing crop by simply turning under a good grass sod, or a cow- pea, soybean or velvet bean stubble, but it does not compare with that added when the whole plant is turned under. The question for the grower to decide is Avhether it is more profitable to harvest the crop for hay, with the idea of feeding it to livestock and return- ing the manure to the land, than to turn it all under. The problem resolves itself into whether the grower has the livestock to which to feed the crop ; if he has and is a good feeder it is probably more profitable to add tlie fertility to the land in the form of manure provided the manure is well cared for prior to its application to the soil. Experiments have demonstrated that more plant food is added to the soil when the crop is allowed to reach a fair stage of maturity before turning it under. This is comparable to what has been learned, regarding the best stage at which to cut silage corn in order to get the maximum feeding value out of it. Phosphoric Acid Potash 14.0 Iha. 54.0 lbs. 45.95 lbs. 101.9 lbs. 18.8 lbs. 54.8 lbs. 33.0 lbs. 155.0 lbs. 30 FOOD REQUIREMENTS— HOW SXJPPLIED Van Slyke (I.e. p. 556) gives the following data relative to the average fertilizing constituents in various leguminous crops. A comparision of this data on cowpeas as presented in the following table, with that published by the Alabama,- New Jersey,^ and South Carolina* stations shows a rather marked difference in results par- ticularly in the case of the Alabama and South Carolina data. Whether these differences were due to heavier yields of cowpeas or to variations in method of making analysis is not quite clear. A careful study of the data as a whole, cannot fail to impress the reader with the importance of employing leguminous cover crops in regions where they can be successfully grown ; or in using clover Comparison of Cowpca Analysis. Nitrogen Van Slyke 54.0 lbs. Alabama Station 123.27 lbs. New Jersey Station 74.8 lbs. South Carolina Station 205.0 lbs. Average 114.3 lbs. 27.9 lbs. 91.4 lbs. or alfalfa in the rotation system in northern sections for the en- richment of the soil. There are also other advantages from the use of green manures, or even in turning under the stubble of legum- inous crops, quite apart from their fertilizing elements. The two most important benefits are those of the improvement of the phys- ical character of the soil by increasing its porosity, and at the same time imparting to it a greater water holding and absorptive capa- city. It also insures greater bacterial activity on the part of the soil flora particularly of the nitrifying organisms. Farm Manures. — The composition of farm manures is ex- tremely variable, because it is entirely dependent upon the nature of the manure, that is, whether horse, cow, hog or sheep manure, how the animals were fed that produced it, and the amount of care exercised in conserving their liquid and solid excrement. Van Slyke {I.e. p. 289) gives the following data regarding the percent- ages of plant food constituents in mixed farm manures. Assuming the average analysis to fairly represent the composition of a reason- ably good grade of farm, manure, the application of ten tons per acre would, theoretically, add 100 pounds of nitrogen, 50 pounds of phosphoric acid, and 100 pounds of potash. These amounts are CO*MMERCIAL FERTILIZER 31 largely in excess of the plant food requirements of a 200-bushe] crop of potatoes. It must be remembered, however, that only one-third to one- half or more of the plant food elements in farm manures are available to the crop to which it is applied. In view, therefore., of the rather unbalanced plant food constituents of farm manure, that is, the relatively low phosphoric acid and high nitrogen content of well preserved manures, it is really more economical to supple- ment the manure with a commercial fertilizer rich in phosphoric acid and low in nitrogen. An application of ten tons of manure per acre before plowing the land and 600 pounds of a 2-8-2 fer- tilizer, that is, 2 per cent of nitrogen, 8 per cent of phosphoric acid, and 2 per cent of potash, at the time of planting should give Composition of Farm Manures. Nitrogen Phosphoric acid Po tash per cent. lbs. per cent. lbs. per cent. lbs. Lowest analysis 0.4 S 0.2 4 0.4 8 Hiohest analysis 0.8 10 0.4 8 0.8 16 Average analysis 0.5 10 .25 5 05 10 good results. This would add 12 pounds each of nitrogen and potash and 48 pounds of phosphoric acid or a total, including that contained in the ten tons of manure, of 112 pounds of nitrogen, 98 pounds of phosphoric acid, and 112 pounds of potash. While these amounts are not equal in phosphoric acid to a ton application of a 4-8-4 fertilizer, they contain more nitrogen and potash. Manure Causing Seal. — Where entire dependence is to be placed on farm manures to produce a crop of potatoes, it is usually preferable to apply the manure to the preceding crop or, in the case of clover, after the first crop has been cut, to be turned under with the second crop of clover in the late summer or early autumn. This is advisable in order to avoid danger of loss from common scab infection, which, if present in the soil, is almost certain to cause more injury to the potato tubers than if manure were not used. Commercial Fertilizers. — The use of commercial fertilizers in potato production is an almost universal practice throughout the Atlantic Coastal Plain section of the United States and throughout the greater part of New England. They are not used extensively in New York State outside of Long Island. Their use is by no 32 FOOD REQUIREMENTS— HOW SUPPLIED means common in the Middle West or Northwest, though it is probable that in many sections they could be employed witli profit. In the early trucking regions in the South the growers use a fer- tilizer containing a higher percentage of nitrogen than those in the late or main crop localities. This is primarily due to the fact that they are desirous of forcing a quick growth of the plant in order to hasten the harvesting of the crop. A formula used rather ex- tensively in the Norfolk trucking section is one that analyzes 7 per cent ammonia, 5 per cent phosphoric acid, and 4 to G per cent of potash. A favorite formula at the present time in .\roostook County, Maine, is one carrying 4 per cent ammonia, 8 per cent pliosphoric acid and 4 per cent of potash. A 5-8-7 is also used quite extensively. When Germany placed an embargo on ])otash, the Maine potato grower was using a fertilizer containing 8 to 10 per cent of potash; but with its sharp advance in price, and a very limited supply on hand, the fertilizer manufacturer found it impossible to offer goods containing over 5 per cent of potash; and only a very limited amount containing 5 per cent potash was obtainable at any price. A large percentage of the fertilizers, offered by the trade in 1916, contained no potash whatever, and one of the favorite no-potash fertilizers was one that analyzed 5-10-0. It was thought by the manufacturers, as well as the growers, that by increasing the percentages of nitrogen and j^hosphoric acid it would in a measure overcome the lack of potash. As a matter of fact, it had the opposite result in many instances ; it had a tendency to induce an unhealthy condition in the plant, which, on the Wash- burn loam soils of Aroostook County, Maine, soon developed well marked cases of potash starvation, accompanied by the premature death of the plant. There is every indication that tubers produced on soil so deficient in available potash as to develop well marked cases of potash starvation in the growing plants, are not as suitable for seed purposes as are those that were gro^vn on soil in which there was a sufficipnt sup])ly of this element. Amount of Commercial Fertilizer to Apply. — In most of the Atlantic Coastal I'lain region the truck growers use all the way from 1500 to 2500 pounds per acre. The same amounts are used in Northern Maine. In the other New England States the amount varies rather widely, say from 800 to 1800 ])ounds with an occasional grower using a ton. In Western New York from 600 to 1200 pounds represent the average range of applications where commer- COMMERCIAL FERTILIZER 33 cial fertilizers are used at all. Tlie same statement will apply to Michigan, Wisconsin, and Miimesota. The use of commercial fertilizers are comparatively unknown west of the Mississippi, except in the southwestern states such as Louisiana, Texas, and Oklahoma. In these states cotton seed meal has been the chief source of nitrog'en. Fig. 10 — Distributing the second applicatii from which the plow and covering disks have been r of fertilizer with the potato planter loved. Aroostook County, Me. The limiting factor in the use of commercial fertilizers in any community is that of the benefits derived from their use rather than their cost. As long as the increase in yield due to the applica- tion of commercial fertilizers is more than sufficient to offset their cost, the grower should make use of them. It is, of course, desirable to determine by experimentation just what element or elements are lacking in the soil, ])efore engaging in any extensive use of commercial fertilizers. Method of Application. — Farm manures may ])e l)roadcasted on the land by hand or with a manure spreader, either before or after the land is plowed. Some growers prefer to plow the manure under while others favor its application to the plowed land. When 3 34 FOOD REQUIREMENTS— HOW SUPPLIED the land is plowed in the fall and it is not of a leachy nature, it is believed that better results will be secured by turning the manure under. When it is applied in the spring to either fall- or spring- plowed land, the application should be made before it is disked, in other words, to secure the best results from the manure it is necessary to have it tlioroughly incorporated with the soil. Farm manures should not be applied to land known to be infested with the potato scab organism, as it is almost certain to increase the number of infected tubers. On such soils it is preferable to apply the manure to the preceding crop. There is less likelihood of Fig. 11. — Broadcasting the second application of fertilizer. Aroostook County, Me. injury to the tubers when the manure is applied to land in the late summer or early autumn and then plowed under. In the case of commercial fertilizers, the method of application varies with the cultural practices followed in planting the crop. Where tlie horse-drawn automatic or semi-automatic potato planters are used, they are generally equipped with a fertilizer dis- tributing attachment which opens up a shallow furrow and drops the fertilizer, which, in turn, is mixed with the soil by the plow immediately in the rear of the fertilizer dropi)ing tube, which opens a slightly deeper furrow for the reception of the seed pieces that are dropj)ed immediately behind it. In New Jersey, Long Island, N.Y., and Maine it is customary to apply the full amount of fertilizer when planting the crop. A few growers, however, prefer to make a second application. Generally these are growers who apply over a ton per acre to the crop. Such growers usually apply COMMERCIAL FERTILIZER 35 about 1500 pounds per acre at the time of planting, and make the second application of from 500 to 1000 pounds over the row, just as the plants are about to push through the surface of the ground. This is usually done with the planter by removing the plow and covering attachment (Fig. 10). The fertilizer is either lightly harrowed in, or is covered over with soil. In some few instances a lime distributor is used in making the second application (Fig. 11). This broadcasts the fertilizer which is then cultivated into the soil. In the South where the horse-drawn potato planter is not exten- FiG. 12. — Applying fertilizer with a 3-row Fig. 13. — Mixing fertilizer in soil with distributor. one-horse cultivator. Deep Creek, Va. sivcly used, or, if employed, does not have a fertilizer distributing attachment, the common practice is to open furrows with a one or two-horse turning plow or a middle buster, and then sow the fertilizer in the furrow by means of a three or four-row fertilizer distributor, (Fig. 12) or with a one-row drill. The fertilizer is mixed with the soil by running a one-horse cultivator through the furrow (Fig. 13). The cultivator, when used for this purpose, is made as narrow as possible. In some sections, particularly ill the Norfolk district, the growers make two applications in the furrow prior to planting. Both are made in the manner des- cribed; the first being applied a week or ten days in advance of planting, and the second just before the seed is dropped. The growers have a theory that the earlier application undergoes cer- tain chemical changes in the soil, which render its plant food more readily available to the potato plant when it begins to push out its roots in quest of food. It has seemed to the writer that this 3& FOOD REQUIREMENTS— HOW SUPPLIED practice has at least one disadvantage in that, when heavy rains occur between the time of its application and the planting of the seed, a large portion of the soluble plant food is washed away. Later api)lications are frequently made by the Southern truck growers. These are referred to as side-dressings, so named because the fertilizer is distributed along the side of the row after the jilants have attained some size. This practice is often resorted to after the plants have received a check due to cold weather or a drought, in order to stimulate a quick gro^^i;h. The fertilizer is oftentimes distributed by hand, but it may be applied with a one- row drill. When a side-dressing is a])plied, it is innuediatoly worked into the soil. A successful grower in New York State broadcasts the major portion of his fertilizer application before second-plowing his po- tato land in the spring. The reason given for this practice is that it places the commercial fertilizer several inches below the surface of the soil and, at the same time, distributes it uniformly over the whole area, thus compelling or stimulating tlie roots of the plant to penetrate deeper into the soil, as well as to send out their laterals in all directions in quest of the plant food contained in the fer- tilizer. Through the development of this extensive root system, the plant is better able to withstand drought or other unfavorable conditions and in consequence thereof can be counted on to give a better yield, one year Avith another, than will those having all their plant food inrmediately beneath or above them, as is the case when the whole application is made in the drill row. In the particular example just cited, the crop grown is a late one. It is doubtful if such a practice would be desirable in the growing of an early crop, as earliness of maturity is the prime consideration. QUESTIONS ON THE TEXT 1. Wliat is the jyrower's problem as regards an ample food su])])Iy? 2. How many of the eighty or more chemical elements now known are found in plants? Name them. .'!. Which of the elements are generally considered Ihe essential ones? 4. Which are most commonly deficient in your local soils? 5. What element or elements are lacking in tlie Inter-iMountain section of the United States? f). Tn general what do the soils of the northeastern United States require? 7. What are the relative amounts of nitrogen, phosphoric acid and potash removed hy a 200-bushcl-per-acre crop of potatoes? 8. How much nitrate of soda, l(i per cent acid phosphate, and muriate of potash would be required to supply this loss to the soil? 9. What sources of plant food may lie use in the enrichment of his soil? QUESTIONS SUGGESTED BY THE TEXT 37 10. Explain the term "{ireen iiiamuiiii;" aTid yive a c-oncrete example of its use. 11. What leguminous and nun-le-iuminous crops are most generally used for the enrichment of the soil? 12. What stage of maturity should a crop reach before turning it under in order to secure a maxinuun amount of benefit? l.'l. How does the nitrogen, phosphoric acid, and potash content of an alfalfa crop compare witli tliat of the other leguminous crops mentioned in the legume table? 14. What is the average percentage content of nitrogen, phosphoric acid, and potash of a reasonably good grade of farm manure? ]."). How many pounds of each would be added by an application of ten tons of manure per acre? 10. What proportion of the plant food elements in farm manures are availalile to the crop to which it is applied? 17. What supplementary fertilizing material is it advisable to use in con- nection with farm manures in sections where the mineral elements are lacking? 15. Where entire dependence is to l)e placed on farm manures, when are they best applied? Give reason. 1!). \\'hy does the southern potato grower use a different grade of com- mercial fertilizer from that of the northern grower? 20. What fertilizer formula is used rather extensively in the Norfolk trucking section? 21. What is a favorite formula in Aroostook County, Maine? 22. What was the result of using a no-potash fertilizer? 28. What amount of commercial fertilizer is it advantageous to use? 24. ^\'hat is the probability of potato growers in the Middle West l)ecom- ing large users of commercial fertilizers? 25. What is the best way of determining what plant food elements are lacking in any particular soil? 20. Are there any disadvantages in the use of farmyard manures? Give reasons. 27. How may the possibility of injury from common scab be avoided? 28. How are commercial fertilizers usually applied to the land in the North? In the South? 20. \Vhat is the theory involved in applying a part of the fertilizer some days in advance of planting the crop? 30. What is meant by a side-dressing? How is it applied? QUESTIONS SUGGESTED BY THE TEXT 1. What amounts of farm manure are applied to potato fields by local growers ? 2. What legume crops are commonly turned under for local crops of potatoes? 3. Calculate the amoTUits of the three fertilizing constituents applied in these ways by one grower. 4. What fertilizer formulas are used by local growers? References Cited 1. Van Slyke, L. L. Fertilizer and Crops, pp. 15, 163, 289, 556, 1917. 2. Alabama Sta. Bid. 14 (n. ser.) 1890, pp. 5-9. 3. New Jersey Sta. Rpt. 1893, pp. 140-150. 4. South Carolina Sta. 2nd. Ann. Rpt. pp. 169-179. CHAPTER VI ' CROP ROTATION Necessity of Crop Rotation. — A system of agriculture which is not based on a definite rotation of crops can hardly be regarded as measuring up to modern agricultural teachings. The theory on which crop rotation is based is that of conserving the natural fertility of the soil by maintaining a proper balance between its mineral elements, sustaining or increasing the humus content, thereby improving its physical condition and, at the same time, restraining the development of injurious fungous and insect pests. Bolley^ has recently demonstrated that the constantly diminishing wheat yield in the Middle West is not so much due to a depletion of soil fertility as to the cumulative effect of constantly increasing soil infection by fungi preying upon the roots of the growing wheat plants. He has also found that a rotation of crops on these lands has served to give increased wheat yields, when this cereal followed other crops such as corn, oats or potatoes, in the rotation scheme. Systems of Crop Rotations. — At the present time, compara- tively few American potato growers practise a definite crop rota- tion system, whereby but one crop of potatoes is grown during the rotation. For example, in the far-famed Aroostook County in northern Maine, where the potato may be said to be the only cash crop grown by a majority of the farmers, it is generally understood that a three year rotation is practised. Theoretically^, the rotation is: potatoes the first year, oats seeded with clover and timothy the second, and a clover crop the third year. The clover rowen, or second crop clover, is plowed under in the late summer or early autumn for the ensuing potato crop. As a matter of fact, however, comparatively few Aroostook farmers adhere to this rotation. A large proportion of them take two, three, or even more potato crops in succession before the land is seeded do^vn. This is particu- larly true on land which is especially well adapted to potatoes. Fields have ])een noted during the past two seasons that were pro- ducing their ninth consecutive crop of potatoes. Such extreme cases of cropping are, of course, comparatively rare ; but the taking of two or three crops in succession is quite common. On the other hand, however, here and there may be noted a grower who is adhering to a well-defined system of crop rotation. The author INTERPLANTING 39 has in mind one party wlio for years has been practising a five year rotation system, allowing the land to remain in grass three years, instead of one. On this farm fifty acres of potatoes are grown annually. It is hardly necessary to say that, under this system of cropping, profitable yields of high class potatoes are being secured. Interplanting. — In the trucking regions of the Atlantic sea- m&\ Fig. 14. — Potatoes interplanted with corn. board, from New Jersey to Florida, a peculiar system of cropping is in vogue. In Florida, for example, the potato crop is planted from the latter part of December to the middle of February, and is harvested from the latter part of March to the latter part of Ma.j. The land is very frequently planted to corn, and occasionally to sugar cane, some time in advance of harvesting the potato crop. In the case of the corn, the planting is usually done with a one-horse planter, so constructed that the seed dropping attachment is set to one side of the center, which permits the drilling in of the corn on the side of the potato ridge (Fig. 14). When the harvesting of the potatoes is delayed by unseasonable weather, or by unfavorable prices, the corn plants frequently attain a height of six to twelve or more inches before the potatoes are removed (Fig. 15). 40 CROP ROTATION In sucli instances, of course, and in fact iti all cases where the sides of the potato ridges are planted Avith corn, the harvesting of the crop is very largely done by hand. By exercising a reasonable degree of care it is possible, by using a small one-horse turning plow, to plow out the potatoes. This materially reduces the hand work and effects a considerable saving in labor cost. The sugar cane cuttings are usually embedded near the bottom of the furrow, and are suiiiciently removed from the potato plants to alloAV the use of a potato digger. Annual Crop After Potatoes. — AVhere interplantiiig is not practised, the land may be plaiited to corn as soon as the potatoes Fia 1") — \ iiowlv }iarvested potato Ti 1 uit,-;. Ordinarily it is iiut considered desirable lo have the intercrop rr^i lar au\aniia luiHiiliie i)otato crop is re- moved. Hastings, Fla. are out of the ground ; or the seed is dropped in the furrow between the rows prior to digging. The operation of harvesting the crop covers the corn. Or it may be seeded to crab-grass and allowed to produce a crop of hay. When planted to corn, cowpeas are very frequently sowed among the corn at the time it receives its final cultivation. The cowpeas make a fair growth of vine, conserve and accumulate nitrogen in the soil, and at the same time provide a considerable quantity of vegetable matter to be plowed under for the next season's crop of potatoes, or it may be made into hay. On most of the potato farms around Hastings, Fla., a crop of early potatoes is produced every season, with seemingly little, if an)^, deleterious results, where intelligent care is given to the preparation of the land and the care of the crop. POTATOES CONTINUOUSLY 41 What has been said regarding Florida conditions applies almost equally well to the Charleston, S. C, district. That is, the potato cro]) is followed by corn, cowpcas, cotton, or hay. Strawberries with Potatoes. — In the Norfolk and Eastern Shore trucking regions of Virginia and Maryland, various rota- lion and intercropping methods are pursued. One rotation, fre- quently observed by the writer, is that of interplanting the potato field with strawberry plants. When this practice is followed, the potato rows are spaced from foUr to five feet apart, the young strawberry plants being set between the rows (Fig. 16). In this Fig. 16. — Strawberry rows five feet apart interplanted with potatoes. Norfolk, Va. way a partial crop of potatoes is secured while the berry plants are becoming established. Another way is to interplant with string beans, or with corn, when an early crop is desired. Where the potato crop is the sole occupant of the land during its growing period, it may be followed with a crop of co^vpeas, soybeans, millet, or corn. Occasionally a second crop of potatoes may be grown. It is not an infrequent practice to grow potatoes two or three years in succession on the same land. There is no distinctive crop rotation system between which might be said to apply to this trucking section. Potatoes Continuously. — In addressing an audience of potato growers in the Louisville, Kentucky, district some time ago, the 42 CROP ROTATION author \yas greatly surprised to have a gentleman arise at the close of the meeting and make the statement that he had heen annually removing two crops of potatoes from land that has heen devoted to this system of cropping, to his actual knowledge, for 33 years. He, furthermore, stated that he had been unahle to detect any diminution in the crop, and was even inclined to believe that better yields were being secured now than formerly. Fortunately, such severe cropping is extremely rare. It is a common practice in that section, however, to repeatedly grow one crop of potatoes per year on the same piece of ground. Such a practice can hardly be regarded as a wise policy to pursue on any soil or in any locality. Potatoes After Alfalfa. — In the "Western potato producing centres, such as the Greeley and Carbondale districts in Colorado, a fairly definite crop rotation system is followed. For example, in the Greeley section potatoes are usually planted on an alfalfa sod land. When potato production was at its zenith in this locality, potatoes frequently followed potatoes for two or three years in succession. At present sugar beets may alternate Avith potatoes, after which one or two grain crops follow before seeding it back to alfalfa, in Avhich crop it may remain from three to four years. Some growers secure two crops of potatoes in the rotation scheme; the first being grown on alfalfa sod, after which a crop of grain follows and then a second crop of potatoes. When potatoes follow potatoes, the second crop from alfalfa sod is frequently better than the first one. These results are obtained only when the land is reasonably free from infectious diseases that prey upon the po- tato plant. At the Greeley Experiment Station, operated conjointly by the United States Department of Agriculture, the Weld County Com- missioners and the Colorado State Experiment Station, a definite four year crop rotation has been established, in which potatoes are grown on alfalfa sod, followed the next season by oats seeded with alfalfa, the oats serving as a nurse crop, and indirectly returning a fair yield of grain; alfalfa is grown the following two seasons. The same rotation has been established at the Jerome Experiment Station, Jerome, Idaho, which is being operated by the United States Department of Agriculture. In the Carbondale district a very similar system of crop rota- tion is in vogue, except that sugar beets are not grown in that ALFALFA IN THE ROTATION 43 region. The general practice is to take two crops of potatoes in succession. Potato-Barley Rotation. — In the "tule" lands of the Sacra- mento and San Joaquiii delta, regions where potatoes have been tlie chief money crop for a number of years, the common practice is to take two or three potato crops in succession, followed by a crop of barley, and then back to potatoes for another two years. The result of such a system of crop rotation has been to so thor- oughly infect the soil with potato diseases as to make the crop, in many instances, an unprofitable one to grow. No Uniform Rotation. — From the foregoing statements, it is evident that there is no general and well-defined system of crop rotation that is rigidly adliered to in any of the large potato grow- ing centres. The desirability of rotating crops is well understood, but the temptation to grow a money crop as often as possible is great; so that the ultimate benefits accruing from the practice of a sane crop rotation system, are often sacrificed to the prospect of immediate gain. A potato crop rotation system suitable to each potato producing section could easily be adopted if the growers desired. The three-year system, supposedly practised by the Maine potato growers, is probaljly as desirable as could be devised for that section. As a rule, a good clover stand is easily secured; and the crop grows luxuriantly, so it affords a cheap source of plant food and serves to maintain and even increase the humus content of the soil, thereby keeping it in good physical condition. Alfalfa in the Rotation. — Where alfalfa can be grown as suc- cessfully or more so than clover, it should be substituted for it, a. id at least a four year rotation adopted. It may be that, where it seems desirable to allow the land to remain in alfalfa three or four years, two crops of potatoes may be permissible in the rotation by growing a crop of grain between them. The following rotations are suggested for alfalfa growing sections : I. 1st year, potatoes on alfalfa sod; 2nd year, oats, wheat or barley seeded with alfalfa; 3rd and 4th years, alfalfa. II. 1st year, potatoes on alfalfa sod; 2nd year, wheat; 3rd year, potatoes; 4th year, oats or barley seeded with alfalfa; 5th, 6th and 7th years, alfalfa. 44 CROP ROTATION For clover growing sections wli('r(> aH'alfa doot^ not succccmI, two rotations are hero given : I. 1st year, potatoes on clover sod; 2nd year, oats or barley, seeded down with clover, timothy and red top ; 3rd year, hay. IT. 1st year, potatoes on clover sod; 2nd year, oats or barley, seeded v\"ith clover, timothy, bluegrass and redtop; 3rd and 4th years, hay. In the trucking sections oC the South the diversity of crops grown, and the fact that two or three truck crops may be grown annually, makes the task of devising a suitable crop rotation system an extremely perplexing one. Where careful attention is given to the plowing under of cover crops, potatoes may follow potatoes 3'ear after year, with apparently little, if any, diminution in yield or in quality. On the other hand, a safer and saner plan to follow would be not to grow potatoes oftener than once in two years; always planning to turn under some cover crop for the ensuing crop of potatoes. QUESTIONS ON THE TEXT 1. On what is the theory of crop rotation baaed? 2. What has Bolley demonstrated to be one of the reasons at least, for the constantly diminishing wheat yield in the Middle West? '!. What crop rotation is supposed to be followed by the Aroostook, Maine, potato grower? 4. What is the actual practice of a large majority of the Maine growers? 5. What system of crop rotation is followed in Florida? 6. What is the system of crop rotation practised in the trucking regions of Virginia and Maryland? 7. What rotation is practised in the Louisville, Kentucky, district? 8. What is the practice in Colorado and other western states? 9. What is the crop rotation system followed at the Greeley and Carbon- dale Stations? 10. Give crop rotation system followed in the reclaimed "tule" lands of the Sacramento and San Joaquin delta regions of California. 11. What crop rotation system is thought most desirable for the Maine potato grower? 12. What are the relative values of clover and alfalfa? i;{. Give four-year rotation suggested with alfalfa. 14. Give seven-year rotation suggested with alfalfa. If). Give three-year rotation suggested with clover. 16. Give four-year rotation suggested with clover. 17. What problems confront one in devising an acceptable crop rotation system for the southern grower? QUESTIONS SUGGESTED BY THE TEXT 45 QUESTIONS SUGGESTED BY THE TEXT 1. Give the most common rotation Ity local potato {^rowers. 2. What is the next most common? Give any other rotation in use. 3. Compare and criticise these rotations. 4. Describe any interplanting with potatoes which you have seen. 5. What bad effects have local growers had from too continuous cropping of the same soil with jJotatoesV References Cited BoLLEY, H. L. 1909. Deterioration in wheat yields due to root-rots and blight-producing diseases. N. D. ma. Press Bui. 33: 1-4, Oct., 1909- re-edited Dec. 1911. CHAPTER VII VARIETIES TO GROW, KIND AND AMOUNT OF SEED TO USE, AND PLANTING METHODS Choice of Varieties. — The first question to decide in the pro- duction of a crop of potatoes is that of the variety to grow. A variety should be selected that is adapted to the region in which it is to be grown. As a rule varietal adaptations are now fairly well recognized in most large potato producing centers or districts. If the crop to be produced is intended to supply an early market it will, of course, necessitate the choice of an early variety. The choice of a variety must, therefore, be governed by its adaptability to its environment, and the season of the year in which it is to be marketed. There is one other consideration in the choice of a variety, and that is whether it is to be growai for seed or for table purposes and whether the tuber is rough or smooth (Fig. 17). The leading commercial varieties of potatoes are rather few in number compared with the long list of varieties or varietal names catalogued by the seedsmen of this country. The following list is believed to include all the varieties of strictly commer- cial importance. Early Varieties Medium or late maturing varieties Irish Cobbler Burbank Pearl Triumph Russet Burbank McCormick Early Ohio Rural Perfect Peachblow (Red McClure) Spaulding No. 4 Russet Rural Brown Beauty Green Mountain American Giant Chas. Downing (Idaho Rural) To this number might be added a supplementary list of varieties, such as the Early Rose, Beauty of Hebron, White Rose, and Up-to-date. As the above varieties, vni\\ but two or three exceptions, are discussed in more or less detail in Chapter XXII, further elabora- tion is unnecessary, beyond saying that it should be understood that the Green Mountain, Rural, Burbank, etc., include the various members of the groups tliey represent. The Brown Beauty is evidently a variety of English origin as yet unidentified. It is the leading variety grown in the San Luis Valley district in Colorado 46 GOOD SEED DEFINED 47 where it is very popular. The White Eose is a popiiLar variety in certain sections of California. A variety masquerading under the name of the Oregon White Rose, and another under the name of British Queen have become popular in western Oregon and cer- tain localities in California. The two varieties seem to be identical and both are improperly named. Our own observations lead us to believe that they belong to the Up-to-Date group of ])otatoes. Fig. 17.— ^A uniform lot of high grade seed stock, grown on the Sweet ranch, Carbon- dale, Col. Kind of Seed to Use. — The importance of using good seed potatoes can scarcely be overemphasized. The customary practice of using what is left from the season's crop, after marketing or consuming the best of it, must be discontinued if the present quality and yield of the potato is to be materially improved or increased. It is as useless for the potato grower to expect maximum yields from inferior seed stock, as for the dairyman to hope to develop a superior milking strain from scrub stock. Nature does not work in tliat way. Good Seed Defined. — Good seed mav be described as stock 48 PLANTING METHODS GOOD SEED DEFINED 49 tliat is pure Avitli rospect to the yariety; that has heen produced by healthy, vigorous, heavy-yielding plants grown under favorable climatic conditions; that is somewhat immature, reasonably uni- form in size and sha|iO (Figs. 18 to 21), and firm and sound, with the first sprouts beginning to develop at planting time. vSeed of this character is now procurable in somewhat limited quantities from growers who have recently begun to specialize in seed produc- tion in Maine, Vermont, New York, New Jersey, Maryland, West Fig. 19. — Seed tubers showing desirable stage of germination; first sprouts just pushing out. Virginia, Michigan, Wisconsin, Minjiesota, Nebraska, Colorado, Idaho, Oregon, Washington, and California. In all of these states provision has been made for the inspection and certification oi' the seed stock of growers who have made proper application for such inspection service, and whose fields and the crop harvested from same have been found to fulfil the inspection requirements. As yet, the amount of seed available in these various states rep- resents but a small fraction of that required for planting the total acreage of the state or the country as a whole. Certified seed necessarily commands a considerable premium over that which has not been inspected, but the extra cost of the 50 PLANTING METHODS &5 i'ry«'-"i>K«isr .,. S GREENING AND GERMINATING 51 seed is slight as compared to the increased yields which may be expected from tlie use of good seed and the crop insurance which it affords. Seed disinfection is discussed in the chapter on diseases. Greening and Germinating or Sprouting Seed. — The practice of greening and germinating seed potatoes before planting them, in order to hasten the development of marketable tubers, is one that is (^ommonly employed by growers of early potatoes in Great Britain and on the Continent, but is little used by American growers. The British growers use a special seed tray or flat, con- FiG. 21. — Greened and well-germinated Irish Cobbler seed tuber. These sprouts are about the right stage of development. Note how short and stubby they are. Such sprouts are tough and are not easily broken off. structed with corner posts from four to five inches higher than the sides, to which a narrow strip of board is nailed across the upper end. This strip serves as a handle in lifting or moving the flats and, when tiered one above another in the germinating room or house, provides an open space between the flats. The dimension of the tray is immaterial, except that it should be of a convenient size to handle. A tray having an outside dimension of 16 by 30 by 3 inches has been found by the writer to be very convenient to handle (Fig. 22). Such a tray, when filled with medium sized tubers, will hold approximately fifty pounds. The primary object of the flats is to furnish a convenient receptacle for the selected seed tubers, in which to expose them to light and sufficient heat 52 PLANTING METHODS to induce slow growing hut vigorous terminal sprouts. The tubers are placed in the flats with the seed end up})erniost, with usually l)ut one layer to a Hat. By placing the seed end uppermost it tends to stimulate the development of strong sprouts from the bud eye clusters, which, in the presence of light, remain short and stubby and are not easily broken oflP (Fig. 21). Many of the English growers place their seed in the trays in the autumn or early winter. Under favorable conditions, a development similar to that shown in figure 23 will be obtained in from four to eight weeks, depend- ing on the season of the year in which they are placed in the trays. Fig. 22. — Tiers of 16x30x3 inch slat-bottomed seed trays, used for storing small lota of seedling potatoes. Such trays are suitable for germinating seed in the light. Not all varieties respond alike to this treatment : in the Eural, for instance, the only eyes producing sprouts are usually those of the seed end (Fig. 21) whereas in the case of the Green Mountain, lateral eyes are just as likely to start into growth as the terminal ones. Where shallow trays are not available it is ])ossible to green and germinate tlie seed tubers by spreading them out rather thinly on a floor or the ground, Mdiere they can be protected from frost and at the same time be exposed to light during the daytime. By turning over the tubers every four or five days with a wooden rake or a potato scoop shovel, most of the tubers will be exposed to the light during some portion of the germinating period. Two GREENING AND GERMINATING 53 to four weeks exposure will usually be enough to start germina- tion sufficiently to enable the one who cuts the seed to select those eves that show an active growth. The benefits derived from greening and germinating the seed before planting it are not confined to the securing of a better stand and a quicker maturity, but it is claimed that a heavier yield is also obtained. Greig" reports increased yields from germiiuited Fig. 23. — True to type Peachblow seed potatoes, showing the master sprout, which is the strongest sprout the potato can produce, and if it is allowed to grow no other sprout will be started. Courtesy L. D. Sweet, Col. over ungerminated seed of from 34 to 39.5 bushels per acre. Still larger increases are mentioned^ in which gains of from 61.6 to 74.7 bushels were obtained. Tlie extent to which the sprouting of seed potatoes is practised in Great Britain can be judged from the following item which appeared in the Agricultural Gazette, volume 87, p. 188, 1918, "The Food Controller has decided, in special circumstances, to grant licenses to dealers to sell sprouted seed potatoes at a price not exceeding 30 shillings per ton in excess of the price allowed for the same variety of unsprouted seed pota- 54 PLANTING METHODS toes." Some of the larger Jersey Island potato growers sprout hundreds of tons of seed potatoes each year. In America, this metliod of securing earliness of maturity of tlie resultant crop offers greater possibilities, in tlie writer's judg- ment, to tlie growers of tlie North tlian of the South. The reason for this is that the southern grower ordinarily plants his early potato crop when the groujid is cold, and while cool and even quite frosty nights prevail. Under these conditions the seed pieces are Fig. 24. — An extensive root is developed before the stems appears above ground. slow in germinating, and it matters little whether they are sprouted before planting or not, because the unsprouted seed has ample time to germinate and become well rooted before the upper layers of soil are sufficiently warm to stimulate stem growth (Fig. 24). It is, of course, desirable to have the seed exposed to light and heat a week or two before planting; but it is questionable whether much benefit is derived from a prolonged greening, such as is practised by overseas growers. Size of Seed Piece. — The question of size of seed piece and whole vs. cut seed is one that has engaged the attention of growers and scientists for over a century and is still not fully answered. The superiority of whole over cut seed or of cut seed over Avhole seed has been repeatedly demonstrated for both; and a student RELATION OF SIZE TO AMOUNT OF SEED PER ACRE 55 of the literature of tliis subject soon arrives at a point where he is convinced that tlie question of superiority of whole or of cut seed is one of environment rather than of actual influence of seed piece. In general, the experimental evidence indicates rather clearly that, within reasonable limits, the larger the size of the seed piece used the larger will be tlie total yield. These results are gen- erally secured, however, at the expense of size; that is a larger percentage of the crop will l)e too small for tal)le purposes. This is particularly true with respect to wliole seed. Relation of Size to Amount of Seed per Acre. — Ilardenburg^ as a result of a review of the literature on size of seed piece, concludes that in many of the experiments, false conclusions have been reached, through the neglect of the investigator to take into account the amount of seed used per acre. He illustrates his point as follows : "In tests comparing the influence on yield of whole, half, quarter, and eighth tuljers, the results have generally favored the whole tuber for seed, and it has been concluded that the larger the seed piece planted, the greater the yield is likely to be. In reality, eight times as much seed has been used per acre when whole seed has been used as when eighth tubers are planted Most of these experiments have, therefore in reality not shown that whole tubers are to be preferred to eighth tubers, ])rovided the eiglith tubers are planted enough closer in the row to consume the same amount of seed per acre as Avould be used in case whole tubers were planted." In the main Hardenburg's point is well taken. It is a fact that most of the experimental work that has been done on size of seed piece has not taken into account a study of the most economical distance or spacing of the various sizes of seed pieces in the row. There is no question but that much of the apparent superiority of large over small sizes of seed pieces has been due to the fact that the spacing of the pieces in the row have more nearly ap- proached the most economical distance for the large sized seed piece than of the smaller one. For example, a study of three ounce whole tubers with three ounce halved tubers, that is a one and a half ounce seed piece, with the spacing in each instance sixteen inches apart, does not afi^ord a fair basis of comparison ; because it is altogether probable that if the one and a half ounce seed pieces had been spaced ten or twelve inches apart their total yield would have been much greater per acre than at sixtee*i inches apart. 56 PLANTING METHODS On the other hand, it is altogether likely that if the three-ounce whole tubers had been given the closer spacing, the yield of market- able tubers would have been materially decreased. A careful study of the right spacing to allow for different sizes of seed pieces in order to secure a maximum yield of marketable tubers is needed for each of the leading commercial varieties, in order to furnish a comparable basis for the determination of the relative value of whole vs. cut seed or large vs. small seed, regardless of whether it is whole or cut. Fir,. 2.") — Socd-PuttiiiK hopper-boxes with stationary knives greatly farilitate the task of preparing the seed for planting. Courtesy of Daniel Dean, Nichols, N. Y. When such studies have been made, it is quite likely that it will be found that too large or too small seed pieces, whether they are whole or cut, are not economical to use ; and that the most desirable size of seed piece from the standpoint of net marketable yield will involve the use of a much larger quantity of seed than is now ordinarily employed. Influence of Season. — It will also be found that d liferent seasonal conditions favorably or adversely affect the" results secured from different sizes of pieces even with proper spacing. For ex- ample, maximum results from whole tubers or from large sizes of cut seed can only be secured when there is sufficient available plant food and moisture in the soil to enable the plants to develop the tubers they set to a marketable size. It is also equally certain that small sizes of seed pieces are more likely to be injured by unfavor- able soil or weather conditions after planting. If the soil is too SIZE IN IRRIGATED REGIONS 57 dry, many of the seed jjieces will fail to grow; and if it is too wet and cold, it is obvious that more of them will decay than of the larger sizes of seed pieces, particularly if whole seed has been planted. Xegleet to take these and many other factors into consideration has led to numerous erroneous conclusions relative to the merits of large and small sizes of seed pieces. Size in Irrigated Regions. — It is believed that in the irrigated regions of the West, where it is possible to supply the necessary Fig. 26.— Cutting with stationary knife. The cutting edge of the blade should face in the same direction as the operator. Both hands are free to handle the tuber. amount of moisture, the use of medium sizes of whole seed — say from 2 to 4 ounces in weight — of such varieties as the Rural New Yorker No. 2 and the Eusset Burbank, will give better results than cut seed. There is reason to believe that in the case of the Charles Downing (Idaho Eural) the use of whole seed will be found un- desirable, on account of its habit of producing more stems per given weight of seed piece than the other two varieties, and also to its inherent tendency to set a larger number of tubers per stem. It is apparent, therefore, that the variety itself is an important factor in determining the best size of seed piece to use. 58 PLANTING METHODS General Practice Regarding Size. — Generally speaking, it is advisable to use a liberal size of seed piece, one weighing from one and a fourth to two ounces. As a rule, this will contain from one to throe eyes. A three-ounce tuber cut in two or a four-ounce cut into three pieces has given very satisfactory results. The list of references on size of seed piece to use is by no means a complete Fig. 27. — A set of adjustable knives fastened in a frame resting on a slat crate. A sharp blow from the wooden mallet forces the tuber through thereby dividing it as many times as there are blade sections covered. one, but it will serve to show the amount of interest shown in this subject. Cutting the Seed. — For the most part, seed potatoes are cut by hand rather than Avith automatic cutters; but the scarcity and high cost of labor and the continual improvement of automatic seed-cutting implements are having a tendency to increase their use, even though they are not as satisfactory as hand work. Thus far, no automatic seed-potato cutter has been devised which is able to distinguish between weak and strong eyes or no eyes at all; hence there is bound to be a certain percentage of seed pieces which WHEN TO CUT SEED 59 will not produce plants, or if they do, they will be weak. On the other hand, all seed pieces that have been carefully cut by hand will contain one or more strong eyes (Fig. 24). A seed-cutting box or hopper such as that shown in figure 25 with stationary knife blade, or without the hopper as shown in figure 26, greatly mininiii^es the labor of cutting seed. The home- made device shown in figure 27, if used by a careful operator, will Fio. 28. — An 8K ounce Green Moun- tain tuber before cutting. Fig. 29. — First step in cutting the 8J< ounce tuber. Cut from seed to stem end. give a low percentage of eyeless seed pieces. Figures 29 and 30 illustrate the process of cutting a large tuber (Fig. 28) into single eye pieces. The tuber should be cut so as to make blocky rather than wedge-shape seed pieces ( Fig. 30 ) . The advantage of a blocky seed piece is that it is handled better in the planter, and is less likely to dry out or to decay in the ground if the weather conditions are unfavorable. When to Cut Seed. — As a rule, seed potatoes are cut about as required for planting; but when large acreages are to be planted and labor is scarce, it is often found more economical, as well as more convenient, to cut the seed in advance of the planting season. One of the most noted examples of cutting seed considerably in 60 PLANTING METHODS advance that has conio to the writtr's attention, is the practice oi' tlie growers in the Louisville, Kentucky district of cutting their seed potatoes, during December and January, for not only their spring crop but the fall one as well. In other words, part of the December and January cut seed is planted in March or early April, and the balance used for the second or fall crop in July. When Fig. 30. — Final result in cutting an 85-4 ounce tuber into as many one-eye seed pieces ssible. Pieces at seed end have more than one e.ve. Note blocky shape of seed pieces. Average weight of pieces is 54 of an ounce. the seed is cut considerably in advance of its use, care must be exercised in handling the freshly cut material in order to avoid injury from overheating while it is curing. Dusting Freshly Cut Seed. — The freshly cut seed handles ))etter if sprinkled as cut with land plaster, air-slaked lime, or flowers of sulfur. These materials tend to dry the cut surface, and lessen the danger from heating if the weather is warm and the seed is not j)lanted immediately. Treatment of Seed. — The curing or drying ])rocess is facili- tated by the use of one of the a})Sorbents mentioned, and then plac- ing the seed in slatted crates or spreading it out, in a thin layer, RATE AND DISTANCE OF PLANTING 61 on the floor of a frost-proof house, if in the winter season, turning it over once or twice during the first twenty-four hours, and once during each of the following two days ; after which the cut surfaces are generally dry enough to permit of being stored in barrels, sacks, or bins until needed for planting. Some growers prefer to handle their seed in this manner rather than to cut it as needed, claiming that they obtain much better results. But, whatever the method adopted, the important thing to remember is that, if the weather is warm, freshly cut seed develops heat very rapidly and that, under these conditions, its vitality is quickly injured. Many a poor stand has been attributed to the poor quality of the seed stock or to the imperfect operation of the planter when, in reality, the real cause was due to impro])er handling of the cut seed. Rate and Distance of Planting. — The rate or distance of planting should be largely governed by the following factors: (1) the variety grown; (2) the natural normal rainfall of the section, and the moisture-holding capacity of the soil; (3) the supply of available plant food it contains; and (4) the size of the seed piece used. In some sections in Europe early varieties are frequently planted in rows 24 inches or less apart, with an 8-inch to 12-inch spacing in the row. Similar close planting was noted near Eimouski, Province of Quebec, Canada, in 1918. In this country the rows are seldom less than 30 inches apart and only occasionally at that distance. As a rule such varieties as Irish Cobbler and Tri- umph are spaced from 32 to 34 inches apart and from 8 to 12 inches apart in the row. The following discussion on spacing is from Farmers' Bulle- tin 10G4^: "In x\roostook County, Maine, early varieties such as the Irish Cobbler, Triumph, and Early Rose are usually planted in rows 32 to 34 inches apart and from 8 to 12 inches apart in the row. The Green Mountain, which is the leading late variety of that region, is planted in rows from 34 to 36 inches apart and the plants in the row, 10 to 14 inches apart, depending on tlie size of the seed piece used." The table in Bulletin 1064, shows the number of seed pieces required for an acre when planted at different distances. A study of the data presented in this table show that the closest spacing, 30 by 8 inches, would require 26,136 seed pieces to the acre as compared with 14,520 for a spacing of 36 by 12 inches, which is the more common planting practice. The wider spacings included 62 PLANTING METHODS in the table are not infrequently encountered in the dry-farming sections of the West, where the deficiency in moisture makes it impossible to grow potatoes successfully at the distances usual in the humid areas of the United States. "A comparison of the two extremes in spacing shows 26,136 seed pieces in one and 3,630 in the other, the ratio between the two being 1 to 7.2; in other words, the number of seed pieces required to plant an acre 30 by 8 inches apart would plant 7.2 acres 48 by 36 inches apart. Number of seed pieces required to plant an acre of potatoes at different spacings. Pieces of potato seed required at stated spacing distances (number) apart 8 inches 10 inches 12 inches 14 inches 16 inches 18 inches 24 inches^ 36 inches 30 inches 26,136 20,909 17,424 14,935 13,068 11,616 8,712 5,808 32 inches 24,502 19,602 16,335 14,001 12,251 10,890 8,168 5,445 34 inches 23,061 18,449 15,374 13,178 11,531 10,249 7,687 5,125 30 inches 21,780 17,424 14,520 12,446 10,890 9,680 7,260 4,840 42 inches 18,669 14,935 12,446 10,668 9,334 8,297 6,223 4,149 48 inches 16,335 13,068 10,890 9,334 8,168 7,260 1 5,445 3,630 Amount of Seed Required. — "The number of bushels of seed employed in planting an acre of potatoes varies considerably in different parts of the country. Eoughly stated, the quantity actu- ally used varies from 5 to 18 bushels per acre. The average quantity of seed planted per acre in the United States was estimated several years ago by the Bureau of Crop Estimates at 8.6 bushels. As a rule, the smaller quantities are used by the southern truck grower, who is generally obliged to pay a high price for seed stock on account of his distance from the source of its production and the season of the year at which he has to have it delivered. In Aroostook County, Me., the common practice is to plant from 5 to 6 barrels of seed per acre, or from 825 to 990 pounds (13.7 to 16.5 bushels). In order to afford a ready reference to the actual quantity of seed required to plant an acre with seed pieces of definite weights at a given distance between plants, the next table has been prepared to cover seed pieces ranging from half an ounce to two ounces in weight. It will be noted that plantings made at close intervals with seed pieces ranging from one and a quarter to two ounces AMOUNT OF SEED REQUIRED 63 Number of bushels of potatoes required to plant an acre at different spacings with seed prices of various sizes. Spacing of rows and seed pieces Rows 30 inches apart: 8-inch spacing. . . 10-inch spacing. . 12-inch spacing. 14-inch iipaeing. . . 16-inch spacing.. . 18-inch spacing... 24-inch spacing.. 36-inch spacing.. ■ Rows 32 inches apart: S-inch spacing. . . 10-inch spacing.. . 12-inch spacing.. . 14-inch spacing.. . 16-inch spacing. . . 18-inch spacing.. . 24-inch spacing. . . 36-inch spacing. . Rows 34 inches apart: 8-inch spacing. . . 10-inch spacing. . . 12-inch spacing. . . 14-inch spacing.. . 16-inch spacing.. . IS-inch spacing. . . 24-inch spacing. . . 36-inch spacing.. . Rows 36 inches apart: 8-inch spacing. . . 10-inch spacing. . . 12-inch spacing.. . 14-inch spacing.. . 16-inch spacing.. . IS-inch spacing.. . 24-inch spacing.. . 36-inch spacing.. . Rows 42 inches apart: 18-inch spacing.. . 24-inch spacing. . . 30-inch spacing.. . 36-inch spacing. . . Rows 48 inches apart: IS-inch spacing. 24-inch spacing 30-inch spacing 36-inch spacing. Seed requ ired, the average we ight of see 1 pieces us ed being as (bushels) J 2 ounce % ounce 1 ounce l^iozs. l>^ozs. 13^ ozs. 13. G 20.4 27.2 34.0 40.S 47.6 10.9 16.3 21.8 27.3 32.6 38.1 9.1 13.6 18.2 22.7 27.2 31.8 7.S 11.7 15.6 19.4 23.3 27.2 6.8 10.2 13.6 17.0 20.4 23.8 6.0 9.1 12.1 15.1 18.2 21.2 4.5 6.8 9.1 11.3 13.6 15.9 3.0 4.5 6.0 7.5 9.1 10.6 12. S 19.1 25.5 31.9 38.3 44.7 10.2 15.3 20.1 25.5 30.6 35.7 8.5 12.8 17.0 21.3 25.6 29.8 7.3 10.9 14.6 18.2 21.9 25.5 6.4 9.6 12.8 16.0 19.2 22.4 5.7 8.5 11.3 14.2 17.0 19.8 4.3 6.4 8.5 10.6 12.7 14.9 2.8 4.2 5.7 7.1 8.5 9.9 . 12.0 18.0 24.0 30.0 36.0 42.0 9.6 14.4 19.2 24.0 28.3 33.6 8.0 12.0 16.0 20.0 24.0 28.0 6.9 10.3 13.7 17.1 20.6 24.0 6.0 9.0 12.0 15.0 IS.O 21.0 5.3 8.0 10.7 13.3 16.0 18.7 4.0 6.0 8.0 10.0 12.0 14.0 2.5 3.8 5.0 6.3 7.6 8.8 11.3 17.0 22.7 28.4 34.0 39.7 9.1 13.6 18.1 22.7 27.2 31.7 7.6 11.3 15.1 18.9 22.7 26.5 6.5 9.7 13.0 16.2 19.4 22.7 5.7 8.5 11.3 14.2 17.0 19.8 5.0 7.6 10.1 12.6 15.1 17.6 3.8 5.7 7.0 9.5 11.3 13.2 2.5 3.8 5.0 6.3 7.6 8.8 4.3 6.5 8.6 10.8 13.0 15.1 3.2 4.9 6.5 8.1 9.7 11.3 2.6 3.9 5.2 6.5 7.8 9.1 2.2 3.2 4.3 5.4 6.5 7.6 3.8 5.7 7.6 9.5 11.3 13.2 2.8 4.2 5.7 7.1 8.5 9.9 2.3 3.4 4.5 5.7 6.8 7.9 1.9 2.8 3.8 1 4.7 ').7 6.6 64 PLANTING METHODS require quantities of seed very greatly in excess of those ordinarily used. On land Avell supplied with organic matter, an abundant supply ol' available plant i'ood, and moisture, the use of large-sized pieces or whole tubers from one and a half to two ounces in weight will usually prove a pro(ital)le investment. "A safe general rule to follow in planting potatoes is to in- crease or decrease the distance between the rows, as well as the hills, in accordance with the size of the seed piece used, the variety grown, the fertility of the soil, its moisture-holding capacity, and the average normal rainfall that may be expected when the plants are developing their tubers. The nearer the soil and weather condi- tions approach the ideal, the larger the seed piece and the closer the l)lanting. Early-maturing varieties may be planted more closely than the late-maturing sorts, because the plants, as a rule, do not grow as large. "A study of the talde discloses the fact that the quantity of seed re- quired for planting an acre of pota- toes with 3-ounce pieces at a spacing of 30 by 8 inches is more than 54 bushels. When the spacing in the row is doubled, that is, made 30 by IG inches, only one-half this It is believed that when seed pieces averaging 2 ounces in weight are used, a spacing of 13 to 14 inches may be expected to give better results than 10 to 13 inches. In other words, tlie spacing of the plants in the row is to a large extent governed by the size of the seed piece used," Planting Methods. — The seed jneces may be either planted by hand or with a machine. In the South, where hand planting is more generally practised than in the North, the usual practice is to open up a furrow with a one or two-horse plow or middle buster, distribute and mix the fertilizer in the furroAV, then drop the seed by hand (Fig. 31) and cover it with a ])low. In the tule lands of the delta sections of tlie Han Joaquin and Sacramento rivers near Stockton, California, seed is dropped ]jy band in every oilier furrow Fig. 31. — The old time way planting potatoes. Portsmouth, Va. quantity will be required. TYPES OF PLANTERS 65 ■■if^"*|P as the land is being plowed; while in certain parts of Michigan and Wisconsin, and probably other middle western states, some growers mark their land in both directions with a sled or other horse-drawn marker and then plant and cover the seed with a hand potato planter (Fig. 32). It should be stated that in some New England sections where but small acreages are grown the seed is dropped in open furrows in much the same manner as in the South. Types of Planters. — Horse drawn machine planters are of two general types, viz., the one-man or picker (Fig. 33), and the two- man type (Fig. 34). In the former, the seed pieces are picked up by forks attached to a re- volving vertical disk which passes through a comi)art- ment containing the cut seed. The seed piece thus ])icked up by each fork is stripped off as it passes between two finger-like attachments and falls into the dropping tube. Accu- racy in planting is largely dependent on the uniform- ity in size and shape of the seed pieces. Blocky shaped pieces are much more sat- isfactorily handled than wedge-shaped ones. The Two-Man Macliine. — In the operation of the two-man planter the seed pieces, in one type, are raised singly from the hopper by a revolving cogged wheel set at an angle, and deposited in the pockets of a horizontally moving disk, which discharges the seed piece from each pocket as it passes over the dropping tube. The accuracy of this machine is dependent upon the ability of the second man, who sits in the rear, to see that each pocket has a seed piece and to remove any extra pieces that may be in others (Fig. 34). With a good man in the rear this machine will plant 100 per cent perfect; whereas with the picker type, if a fork failed to get a seed piece in its revolution through the supply chamber, or another fork spears two or more pieces, there is no one to correct these mechanical errors. 5 66 PLANTING METHODS The Picker Planter. — The advantages of the picker type of planter are: (1) that it onl}- requires one man to operate it; (2) that, on account of its automatic distribution of the seed, it is possible to drive the horses somewhat faster, thereby planting a larger acreage per day. Its disadvantage is that there is no one to correct the mechanical errors, such as have been previ- ously mentioned. ■■r— J ^^ t ^r^ ^^K m M ^^.(imA : . n ^ I ■'"* ■■ j^^^BW' .> ■/" -^ y^-^i OiS ^K..- '-^ W\ ...l^jPi ... . ■ ■ ^^^?^^^- -^^ K ;^f Fig. 33. — A 2-row picker type of planter. The Two Machines Compared. — Many growers feel that the slight inaccuracies of the picker planter are not of sufficient con- sequence to justify the additional cost of operating a two-man planter. Assuming that the picker type of planter drops the seed pieces 95 per cent perfect and that, as a result, the yield is cut, we will say 3 per cent, is this amount sufficient to pay for the extra man ? The answer to such an inquiry is dependent upon two factors, (a) the yield produced; and (b) the price received for the TYPES OF PLANTERS 67 crop. With a Iiundred bushel yiekl and a value of $1.00 per bushel, the net increase would be $3.00. As a two-man planter should average under fair working conditions about 4 acres per day, this would mean with present prices of labor from 75 cents to $1.00 extra cost per acre, but as the picker planter will plant, on an average, more land per day than the two-man planter, a further charge should be made against the latter. In the planting Fig. 34. — Two-man type of planters. Courtesy of Bateman Mfg. Co., Grenloch, N. J. of a 20-acre field of potatoes, let us assume that it required 4 days for the job with a picker planter and 5 days with a two-man planter, and that the cost of operating the one is $7.00 per day and $10.00 for the other. On this basis, the actual cost of planting an acre of potatoes with the picker type is $1.40, as against $2.50 for the two-man planter, or a difference of $1.10 per acre as an offset against the 3 bushel increase in yield. It must be conceded, however, that 100 bushels per acre is rather a low yield, and that a 95 per cent stand is probably too high to represent a fair average. Suppose a yield of 200, 300, or 400 68 PLANTING METHODS biishels were obtained I'roin the ])i(ker-planted field; the profits I'rom the use oi' the extra man are at once more than doubled, trebled, or quadrupled because the initial cost of planting remains the same ; and the only additional cost is in the gathering, hauling and marketing of the extra bushels. Many fields, however, will not show over 90 per cent stand, and, if the seed is not fairly uniform in size and shape, the percentage of stand may be even Fig. 35. — A good stand of Irish Cobbler potatoes. Aroostook County, Me., 1914. less than this ; thus we ma}' have a much larger jjcrcentage of increase. In explanation of the calculation of a 3 per cent gain, instead of 5 per cent on a 95 per cent stand, it should be stated that plants adjacent to missing hills give an increased yield; it has therefore been thought desirable to only claim a 60 per cent increase or 3 instead of 5 per cent. A Perfect Stand Desired, — The main, outstanding object for which the grower should strive is that of securing as nearly a perfect stand as it is possible to secure (Fig. 35). Maximum yields cannot EFFECT OF BAD HANDLING OF SEED 69 be produced when there is a large percentage of missing plants (Fig. oG). Carelessl}" cut seed ])ieces, improperly handled seed or an imperfect phuiting machine all tend to reduce yield. Effect of Bad Handling of Seed. — Poor seed is often the result of injuries to the tubers through rough handling. The prac- tice of many seedsmen of shipping seed to their customers in sacks, instead of heavy pasteboard or wooden packages, is often responsible for much injury. This is Avell illustrated in figures 37 to 39, in which a sack and a pasteboard container are shown as is also the Fig. 30. — A poor stand of potatoes due in large part to poor seed. Jerome, Ida. condition of the stock as received from the express company. The reader can readily draw his own conclusions regarding the desira- bility of the two lots of seed. There is every reason to believe that the same relative difference in the condition of the seed would have been noted if the shipment had been made by parcel post. QUESTIONS ON THE TEXT 1. Is adaptation an important consideration in the selection of a vari- ety ? Why ? 2. What is said regarding the Brown Beauty? Where is it grown? ti. Where is the White Rose grown? 4, Of what importance is good seed? Define good seed. 5. Is it desirable to plant the cull stock? Give reasons. 70 PLANTING METHODS a> a PLANTING METHODS 71 72 QUESTIONS SUGGESTED BY THE TEXT 6. How nearly does the certified seed now produced supply the demand. 7. Describe the method of greening or germinating seed tubers. Give object. 8. To what extent has the question of size of seed pieces been studied? !). Is whole seed superior to cut seed? Can you give a reason? 10. What should constitute a fair basis of comparison as to the relative merits of different sizes of seed pieces? 11. What relation does the supply of plant food and moisture have to size of seed piece? 12. Where and under A\hat conditions may whole tiiliors be used for seed purposes? 13. Why is the Charles Downing unsuited for planting whole? 14. How are seed potatoes usually cut? 1."). Should automatic cutters ))e used? Why? Ifi. With what is it desirable to dust freshly cut seed, as an absorbent? 17. How should the cut seed be treated to preserve its vitality? 18. What factors should govern the rate or distance of planting? 10. What is the usual spacing in the United States? 20. At what distance are Irish Cobblers and Triumphs usually spaced in Maine? 21. What difference is noted for the Green Jlountain? 22. How many seed pieces would it require to plant an acre if they were spaced 30 by 8 inches apart? 23. Wliere are the wider spacings practised? Why? 24. How many acres would the seed required for the closest spacing plant if used at the widest spacing? 25. What is the average amount of seed used per acre in the United States? 26. What is the average amount used per acre in ]Maine? 27. How is the seed usually planted? 28. In what sections of the country is hand planting still very largely practised ? 20. Into what two classes or types are horse drawn planters divided? 30. Describe the mechanical operation of the picker type of planter. Give advantages and disadvantages. 31. Describe the operation of the two-man planter. 32. What is the approximate cost of planting an acre of potatoes with a one-row picker machine? With a two-man type of planter? 33. What is the main outstanding object for which the grower should strive in planting his crop? How secured? QUESTIONS SUGGESTED BY THE TEXT 1. What varieties of potatoes are used for early planting in your region? 2. What ones are used for late planting? 3. What are the sources of these seed potatoes? 4. Is careful selection practised by local growers? Or are culls used by some for planting? 5. To what extent are greening and sprouting practised locally? For which crop? 6. Give the local practices regarding sizes of seed pieces and methods of cutting and treating seed. REFERENCES CITED 73 7. What are the common local methods of planting? Give the distances? 8. What types of machine planters have you observed? What results? 9. What stands have you observed? Give percentages for best and poorest. 10. Assign some of your relasons for poor stands observed. References Cited 1. Anonymous. 1908. Field Experiments. Jour. Dept. Agr. and Tech. htstr. Ireland. 8: 296-297. 1908. 2. Greig, R. B. 1906. The sprouting of seed potatoes. Aberdeen and No. of Scot. Coll. of Agr. Bui. 3:9, 1906. 3. HardenburCx, E. V. 1920. Cutting seed potatoes. The Pot. Mag. 2:6, March, 1920. 4. Stuart, W. 1919. Production of late or main crop potatoes. U. S. Dept. Agr. Farmers' Bui. 1064: 22-25, 1919. CHAPTEK VIII THE CULTURAL CARE OF THE GROWING CROP Systems of Culture. — There are two well recognized systems of potato culture in the Ignited States commonly known as the ridge and level culture methods. In the choice of either of tlu; systems the grower should he guided hy his own environ- mental conditions. Ridge Culture. — In the ridge culture method, the soil between the rows is loosened hy some tillage implement, usually a riding cultivator (Fig. 40), and is then drawn or thrown uj) over or around the i)lants by a winged or disk horse-hoe (Fig. 41). In the Fig. 40 — '1 In laim .~.i.- . . .- ni^>3S^ Fig. 45. — First cultivation with the riding cultivator. Prior to this the surface of the ground was kept loose and the weeds destroyed by the use of the wecder or spike-tooth harrow. This field is being grown under the level culture system. Courtesy of the Bateman Manufacturing Co. eight inches in width, standing uj) four or five inches above the bottom of the furrow exposed to the drying eifects of the sun and wind, will hardly appeal to the reader as a sane cultural operation. If the object of such practice was to root-prune and check the growth of the potato plants, it might be regarded as a very com- mendal)le procedure; but as a stimulant to plant growth it should be classed as a highly undesirable cultural operation. The one- horse cultivator, when proi)erly uged, is just as effective an imple- 80 CULTURAL CARE OF THE GROWING CROP raent in loosening up the soil as the riding cultivator. In the level culture metliod little, if any, soil is thrown toward the plants until the final cultivation, when the outside shovels or cultivator teeth are set at an angle, so as to throw some soil toward the row. Tlie number of cultivations that sliouhl he given is largely depen- FiG. 46. — The last cultivation with the riding cultivator. After this the injury to the root system of the plant is normally greater than the benefits derived from loosening the soil. Courtesy of the Bateman Manufacturing Co. dent on the character of the season and the soil. A safe general rule to follow is to till the crop as often as may be necessary to keep the surface loose and friable. This may be 3, 4, 5, 6, or more times. After the first deep cultivation, tlie subsequent ones should be shallower and shallower and further and further away from the plants. The aim should be to cultivate as much of the intervening HAND HOEING 81 space between the rows as possible, witliout causing material injury to the roots of the plants. Cultivation Avith level culture should cease when the plants are in blooni^ or when the tubers get as large as a hen's egg. When- ever the root pruning becomes severe cultivation should cease. In the case of ridge culture, cultivation may be continued a little later, because the roots of the plants are largely confined to the soil in the ridge, and the slight amount of tillage that is possible Fig. 47. — A 4-inch artesian well near Palatka, Fla. Note volume and rate of flow. in the centre of the row, does little if any injury. As a rule cultivation should cease when the plants are in full bloom or just passing out of it (Fig. 46). Hand Hoeing. — In commercial potato-producing sections the crop is seldom hoed more than once ; and in soil specially free from weeds, the hoe may not be used at all. Where potato growing is not strictly a commercial business, considerable hand hoeing is frequently done. Hand hoeing should, however, be regarded as too expensive a tillage practice to justify its extensive use. The grower should endeavor to destroy the most of the weeds in the 82 CULTURAL CARE OF GROWING CROP earlier stages of cultivation. In some sections, as in portions of Michigan and Wisconsin, the grower attempts to dispense with hand labor by check-rowing the tield, so as to permit of cultivating the crop in both directions ; but such wide spacing reduces the yield per acre and is not to be commended. Special Cultural Features. — In the various production centres of the United States certain cultural practices are in vogue that are both interesting and instructive to those residing in other sections of the country. The Hastings district in Florida, for ex- FiG. 4S. — One row omitted between raised beds for irrigation furrow- ample, is of interest from the standpoint of its irrigation practice and system of growing the potato crop on raised beds. The irriga- tion water in this district is obtained from artesian wells. (Figs. 47 to 50). Artesian water is usually found at from 150 to 175 feet, and throughout the whole area the fldw varies from a few feet to as much as 40 feet above the sea level. Around Hastings, where the land elevation is only about eight feet, many of the wells have a flow pressure of about twelve and a half pounds per square inch. A four-inch well ordinarily furnishes sufficient water to irrigate a 40-acre tract, and a six-inch well easily cares for 60 acres or more. Tests made on the rate of flow of a two-inch well indicated a SPECIAL CULTURAL FEATURES 83 capacity of 80 gallons per minute. The water is more or less strongly impregnated with sulfur, giving it a distinctly hydrogen sulfide smell and taste. It emerges from the well at a tempera- ture Oi 70 degrees F. The irrigation water is applied to the grow- ing crops by means of open ditches or dead furrows between the raised beds on which the crop is grown (Fig. 49). The water spreads out over the somewhat impervious clay sub-soil with which most of the land is underlaid, and is taken up by capillary action. The crop is grown on raised beds of from 8 to 16 rows in width. Fg. 49. — Irrigation furrow or ditch full of water. with deep dead furrows separating the beds; the dead furrows serving as irrigation channels or ditches for the distribution of the water. Drainage ditches have to be provided in order to carry oft' the waste water, as well as to take care of the heavy rainfalls Avhich not infrequently occur in this region (Fig. 50). The drain- age ditch may be closed Avhile irrigation is in progress, but is opened up immediately thereafter, the aim being to remove the surplus or waste water as quickly as possible. Cultivation should follow each irrigation in order to keep the soil loose and well aerated. An implement known locally in the Hastings district as a scooter is rather commonly employed in the later cultivation to loosen up the soil in the bottom of the furrow. In the Beaufort section of South Carolina, as well as in most 84 CULTURAL CARE OF GROWING CROP portions of Soiitlicrii Alahiiina. ]\Iississi|)j)i, anS'. Dipt. Agr. Bui. 61)7, June, 1916. :3. Morris, O. M. 1891. The Potato Crop. Okla. Exp. tita. Bui. 52: 3. CHAFTER X POTATO PRODUCTION IN THE NORTH AND WEST In the preceding chapter, the early or truck crop potato- producing sections in the South were considered hoth with respect to the extent of the crop grown as compared with the total crop of the United States as well as to the relative importance of the crop in each state. It was shown that the 16 states geograi)hically considered as belonging to the South only producecl a little over 15 per cent of the total crop. When it is remembered that this percentage includes all the early, late and fall crop of potatoes grown in the South, the significance of the comparison and the relative importance of ])otato production in the North and West becomes at once apparent. The Potato Essentially a Northern Crop. — While the pro- duction of late or main-crop potatoes is not entirely confined to the North, it is in a commercial sense very largely restricted to the northern tier of states. This is by no means due to an accidental circumstance, but rather to a direct recognition of the fact that the potato is essentially a cool-loving plant; it there- fore thrives best where the summer temperatures are relatively low and where the ra-infall is sufficient to keep the plants in an active stage of growth throughout the season. Such climatic conditions are quite generally found in the northern part of the United States and Canada, and in some of the more elevated por- tions of the South and West. Altitude, as well as latitude, is an important climatic determin- ing influence so far as temperature is concerned, and must be reckoned with in the consideration of the suitability of a given region to any particular crop. Confirmation of these statements, insofar as their application to the late potato crop is concerned, is not lacking as one has only to call attention to the leading potato-producing states, such as New York, Minnesota, Wisconsin, Michigan, Maine and Pennsyl- vania to partially, at least, prove the truth of this assertion. The average production of these 6 states, during the years 1915 to 1919, was over 43.1 per cent of the total crop of the United States. 121 122 POTATO PRODUCTION IN NORTH AND \VEST Market is Another Factor. — It would be misleading, as well as unjust, however, to other equally as well favored states, climati- cally at least, to assume that this large production was Avholly due to exceptionally favorable soil and climatic conditions. There is another factor which determines to a very large extent — in fact, it may be considered the sole limiting factor in many sections of the United States; this factor is that of proximity to market or to the large consuming centres. The potato is a bulky, and rela- tively cheap selling food product, and on that account there is not a sufficient margin between the cost of production and the selling price of the crop to permit of the absorption of a very heavy transportation charge. This limiting factor is, therefore, responsible for the relatively light production of the eleven far- western states. The production of these eleven states for the years 1915 to 1919 has averaged just a trifle under 14 per cent of the total crop of the United States. If one attempted to judge the adaptability or suitability of the various states, in this country or in foreign ones, for the production of potatoes solely by the extent of the crop produced, they would very likely form an erroneous opinion or arrive at an entirely wrong conclusion regard- ing the real causes of heavy or light production. Two Important Factors. — If an intelligent understanding of the subject is to be reached, one must consider the following two factors: (a) average production per acre, and (1)) the produc- tion cost per bushel. These two factors are, of course, largely determined by the progressiveness of the growers as regards their cultural practices and the care they exercise in the production and use of good seed stock. A comparison of the average acre production of the six largest northern potato-producing states with that of the eleven far-western states for the five-year period, 1915 to 1919, shows that the former produced only 90.3 bushels per acre, while the latter averaged 133.3 bushels or an increase of 43 bushels. It is evident, therefore, that the six heavy producing northern states do not enjoy any special advantage as regards climate or soil. The real explanation of their large production is that of proximity to large consuming centres. Late or Main Crop Production Centres. — Potato production in the North and West is not so generally confined to distinctive production centres as in the South. There are, however, certain well known sections which are generally recognized the country over as important potato-producing areas. These sections' are AROOSTOOK COUNTY, MAINE 123 Aroostook County, Maine; Long Island and western New York; Monmouth County, jSTew Jersey; Waupaca and Stevens Point, Wisconsin ; the Eed Eiver Valley in Minnesota and North Dakota ; the Kaw (Kansas River) Valley in Kansas; Greeley, San Luis Valley, Carbondale and Montrose districts in Colorado; the Idaho Falls and Caldwell districts in Idaho; the Yakima Valley in Washington; and the Stockton district in California. While the above localities are the more "widely known potato production cen- tres, they do not necessarily represent all of the important sections. In fact, outside of Aroostook County, Maine, western New York, and Greeley, Colorado, there are a number of other districts such as southern New Jersey, northeastern Ohio ; the central and north- ern portion of the lower peninsula of Michigan, and many others in which potatoes are produced on a much larger scale than in some of the better known areas mentioned. Aroostook County, Maine. — The state of Maine has long enjoyed the distinction of having within its borders a county that lu'oduces on the average more potatoes annually than all but the six leading states, of which Maine herself is the fifth in point of production. It is probably not so well known that the area of Aroostook County is almost equal to that of the Avhole state of Massachusetts and that, notwithstanding its large average annual production of potatoes, I7I/2 million bushels, less than one-fourth of the land in the county has been brought under cultivation. One may well inquire into the reason for this seem- ingly large development of commercial potato production in this somewhat remote market region of the United States. The most logical reasons which present themselves are that the soil and climatic conditions are extremely favorable to the potato crop; the climate is too cool for the successful production of corn or other cultivated cash crops, hence the farmers have come to regard the potato as their chief agricultural money crop; and to look upon grain and hay as merely necessary evils in the practice of a safe and economic crop rotation system. Soils. — The soils of Aroostook County are of glacial origin, but are not thought to have been transplanted very far. They are mostly derived from the shaly Aroostook limestone, which underlies a large portion of this area. West over and EoAve'^ classified the soils derived from the unmodified glacial drift into eight distinct types, the most important of which is the caribou loam. This type of soil is especially suited to the production of potatoes. 124 POTATO PRODUCTION IN NORTH AND WEST Climatic Conditions. — The climatic coiidit ions that i)rovail in Aroostook County vary consiclerabl}' from those which ol)taiii in the southern part of the state. The temperature is much hjwer in the winter and does not rise as high in the summer; the rainfall, while not alwa^ys as copious in the gro^^^ng season, is usually more evenly distributed ; and it is seldom that the potato crop of Aroos- took suffers very seriously from either heat or drought. These two Fig. 5S ,h Cobblers just coming into bloom. factors — heat and drought — exert a much more marked inlhiciice on tuber production than we are wont to consider. Varieties Grown. — The leading commercial varieties grown in Maine are the Irish Cobbler and the Green Mountain. In the case of the latter variety, it is supposed to include the members of the group, such as the Gold Coin, Snow, Norcross, etc. The Irish Cobbler is groM-n both for seed and table purposes, wliih? the Green Mountain is grown almost exclusively for table use. In addition to these, the following varieties are grown for seed pur- poses as, for example, the Spaulding No. 4, American Giant, Triumph, Early Ohio, Early Eose, and Quick Lunch. The last three varieties arc sparingly grown by a few seed growers. AROOSTOOK COUNTY, ]\IAINE 125 Potato Blossoming. — In no other section of the United States yet visited by tlie writer does tlie potato plant bloom as freely as m northern Maine. The reason for tliis is tliat tlie plants rarely sirlfer a clicek in tlieir growtli due to lieat or drought during the period in Avliicli tlie blossoms are developing. As a result of these favorable conditions, many potato fields in northern Maine have the appearance of an immense flower garden (Figs. Fig. 59. — A field of Irish Cobblers in full bloom. Aroostook Co., Me. 58 and 59). The Irish Cobbler and the Green Mountain varieties are especially free bloomers. On account of the favorable climatic and soil conditions in Aroostook County, Maine, the United States Department of Agri- culture has conducted some rather extensive potato experiments in this section since 1911. At present, practically all of the breeding, selection, seed development and varietal testing are located on Aroostook Farm, Presque Isle, Me. (Fig. 60.) (Aroostook Farm is a State Experimental Farm operated by the Maine State Experiment Station). 126 POTATO PRODUCTION IN NORTH AND WEST Production Centres in Aroostook County. — While the county is usually regarded as the unit in the discussion of state production, it is believed that owing to its size, a somewhat more special or minute consideration may be given to certain portions of it. The northern half of the Aroostook Valley is generally conceded to be superior to the southern half for the growing of potatoes. The heaviest producing section is that portion included between Mars Hill, and Limestone, embracing the towns of ]\Iars Hill, Easton, Fig. 60. — Dwelling house and bam on "Aroostook Farm," Presque Isle, Me. Aroo- stook Farm is a State Experiment Farm operated by the Maine State Experiment Station, Orono, Me. The U.S. Department of .Agriculture carries on its potato breeding work on this farm. Fort Fairfield, Presque Isle, Caribou and Limestone. In 1913, the Bangor and Aroostook Railroad prepared a sketch map showing the distribution of potato shipments over their line (Fig. 61). The map also gives the number of miles tributary to each point, the car movement per mile and the percentage of the crop it represents. For convenience of reference the data are considered under ten zone numbers. The heaviest movement per mile of road operated was that of zone 6 or the Fort Fairfield Branch on which 260 cars per mile were moved. The next highest is that of the Limestone Branch, zone 5, with 187 cars per mile, and zone 3, third, with 180 cars per mile. LONG ISLAND, NEW YORK, AND NEW JERSEY 127 The Long Island, New York and New Jersey Districts. — While these two districts are not exactly identical as regards climate and soil, the variations are no greater than those found within Aroostook County. The planting and harvesting seasons are / /. / / ^.^^^^ ' /<^^^l^ 1 1 StockholiA Zone3 fN\ ''V / \\ ^^^K^E^^' ALimeWtone r ' \\ Perh A.?^ 'rft^ \ 1 20N| V l\^fe Fairfield Patten «^ ^ x ''' i \^ \ SHERMANlr>'l.°^'' I^nN 1 irOTACYVlLLE \-T '\ Zone|10 MlLi-lNOCKET, LMlLLlNOCKEjI, W.Seboois Greenviuue^^ Iron^orksJ J^^ 1 bROWNVlLLE^l \f y^SLDTOWN /N^MeJctT _Vbangor /' ISearsport Fig. 61. — Sketch map Bangor and Aroostook R.R. showing distribution of potato shipments. Houlton, Me., April 20, 1917. 128 POTATO PRODUCTION IN NORTH AND WEST also practically identical, thus making it possible to consider them as one district. The points of dilt'erences between the combined sections and that of Maine are that the Long Island and New Jersey areas have two distinctive planting seasons, viz, an early and a late. The Irish Cobbler is almost wholly grown for the early crop and the Green Mountain as a late, with the exception of Monmouth County, New Jersey, where it is supplanted by the American Giant, which is an intermediate variety, planted about Fig. 62. — Harvesting potatoes on a Minch Bros, farm, Bridgeton, N. J. Potatoes are gathered in H bushel baskets. Courtesy of Minch Bros., Bridgeton, N.J. the same time as the early crop. In addition to these three, a red skinned variety belonging to the Eose Group, which we have been unable to identify, is grown to some extent as a late crop, for which purpose it seems to be admirably adapted. rrodudion Cenires. — The chief ])otato-producing centres in New Jersey are located in Monmouth, Salem, Mercer, Middlesex and Cumberland Counties. The chief shipping ])oints are Free- hold, Howell, ]\Iarlboro, Tennent and Englishtown in IMonmouth; Salem, Woodstown, Elmer and Daretown in Salem: Hightstowm, Eobbinsville, Yardville and Windsor in Mercer; Cranbury and Prospect Plains in Middlesex; and Bridgeton and Tlusted in Cumberland Countv. LONG ISLAND, NEW YORK, AND NEW JERSEY 129 The Long Island district is represented by Suffolk County, in which the leading ship])iug points are Riverhead, Aquebogue, Cutchogue, Bridgehampton, Southold, Mattituck and Orient. Soil and Climatic Conditions. — The soil in the more intensive potato-])roducing areas on Long Island and in New Jersey is of a more or less sandy nature, and could be designated as belonging to the Norfolk series, being a continuation of the same general type of soil as that of the Eastern Shore of Maryland and A^irginia. The climate of Long Island is very much modified by the ocean •^*'v '^ of basket'5 Courteby ol Ml bridgLton, \ J irmit of hauling a large number on the south and east and the Sound on the north ; this imparts to the surrounding territory a milder and more equable climate than that which prevails in the same latitude further inland. The climate of New Jersey, especially that of the southern half of the state, is not as well suited to the potato as is that of Long Island, l)ecause it is generally warmer and drier. In New Jersey, the practice of planting second crop home grown seed is on the increase, l)ut the bulk of the seed is procured in the North. Source of Seed. — The Long Island grower is almost wholly dependent upon northern grown seed. Maine, Vermont and northern New York growers supply the bulk of the seed used. Some New Jersey second crop seed is planted, but, as yet, the amount used is rather negligible. During the past year, (1920), Wisconsin Green Mountains, 9 130 POTATO PRODUCTION IN NORTH AND WEST aiid Prince Edward Island American Giants have been planted to some extent. Cultural Practices. — In general, the same cultural methods are pursued as in Maine, with this exception, that both the level and modified ridge culture is practised. The distance and rate of planting is very much the same, as is also the use of commercial fertilizers, with the possible exception that they are not used quite as prodigally as in Maine. As a rule, the fertilizer applied to the early crop contains a higher percentage of available nitrogen than is used by the Maine grower, this being done for the purpose of hastening the development of the plants. Few growers in either of these sections practise spraying as thoroughly as in Aroostook County. This is partly due to the absence of late blight in so many of the seasons that the grower becomes careless and is willing to take a chance, with the result that every few years his crop is severely attacked with the disease, and heavy losses through tuber decay are incurred. This was the case in some counties of New Jersey in 1919, Avhen a severe attack of late blight caused con- siderable loss. Harvesting the Crop. — l^he southern half of New Jersey har- vests its potato crop somewhat in advance of the northern half of the state, as well as of Long Island. The crop movement from New Jersey in 1916, as indicated by percentage of crop harvested, shows that 3 per cent was dug in June, 18 in July, 36 in August, 26 in September, and 18 in October.^ This data affords a fair index to the proportion of the crop that is grown for early and late mar- keting; it is not necessarily an accurate one because, in either of the two districts under consideration, the harvesting of the early crop is materially hastened or delayed, according to whether prices are high or low during the normal period in which it should be dug. A considerable portion of the New Jersey crop is handled in five- eighth l)usliel baskets (Figs. 62 and 63). New England and Northern New York. — The New England States, exclusive of Maine, and northern Nev/ York are sufficiently identical in climatic conditions, cultural practices, and varieties grown to be considered as one general area. With few exceptions, potatoes are not groAvn in this region as an early crop. Outside of northern New York and certain towns in Vermont, very little seed stock is grown other than for local use. The Irish Cobbler is the leading early variety, and the Green Mountain the leading WESTERN NEW YORK AND PENNSYLVANIA 131 late one. The crop is usually planted during May and the first week in June; though in the more favored sections of Connecticut, Khode Island, and Massachusetts,, the crop is often planted in April, especially early varieties such as the Irish Cobbler, Quick Lunch, and others. Few large growers are found in this area, the average acreage of commercial growers ranging from 3 to 20 acres, with an occasional grower considerably exceeding this amount. Western New York and Pennsylvania. — The general potato- producing sections of western New York and Pennsylvania are very much alike, insofar as varieties grown are concerned. Most of the potato crop produced in this region, outside of areas adjacent to the larger cities, con- sists of late varieties intended for fall and winter consumption. A compari- son of the production of these two states during the years 1910-1919, inclusive, shows a variation in New York State from a trifle over 22 million bushels in 1915 to nearly 53.25 million bushels in 1914, with a varia- ,^ ^, t^ . , t^ ,.t- u i ' Fig. 64. — Daniel Dean, Nichols, tion in acreage of only a trifle over n.y. a noted authority on potato J^ •' . . culture who has been highly success- 3 per cent. The range of variation m fui in the production of large crops _ , . » T,,i w- of high quality potatoes. Mr. Dean Pennsylvania was from a little over 15 makes a speciality of the Rural New ■ -.■,. -, , , . ^rv^^x c\r\ r' ^^1^ Yorker Variety. He is also well known million bushels m 1911 to 29.5 million as a writer and platform speaker. His irnrv 'i.!, • • i> practical experience coupled with m 1917, With an acre increase m lavor keen powers of observation and an of the latter period of about 16 per S ma^Yim 'l^Tr^ifuf wrto cent. The varieties most commonly ^^^d lecturer, grown are chiefly members of the Green Mountain and Eural groups. The Eural varieties are more generally grown as they have proven to be better adapted to the climatic conditions of western New York and certain sections of Pennsylvania than the Green Mountain class. In Washington County, New York, the American Giant is rather extensively grown for the New Jersey seed trade. The Irish Cobbler and the Early Ohio are the leading early varieties. Cultural Practices. — Cultural practices vary in different locali- ties. In some sections the planting of the late crop is delayed until the latter part of May or forepart of June ; this is particularly 132 POTATO PRODUCTION IN NORTH AND WEST true ill western Now York, wliile in other sections, the cro]) is planted the latter part of April or early in May, The date of planting is governed, to a large extent, by the normal weather conditions prevailing in any given locality at the time the plants are developing their tubers. Roberts and Clijiton ^ say : " Early ])lanting of potatoes and frequent tillage to conserve moisture M'ill ordinarily give best results." The New York growers, as a rule, plant larger acreages than do New England or Pennsylvania growers. Modern potato imple- ments are very generally employed in the jdanting, care, and harvesting of the crop. The ridge or hilling system of culture is quite generally practised throughout New York State. There are those, of course, who prefer level culture but they are in the mi- nority. In Pennsylvania, both systems are in vogue. Investiga- tions reported by Stone,*^ in 1905, would seem to indicate that level culture, at least in the vicinity of Itliaca, was preferable to hilling. The following data covering three seasons are taken from Stone's report : hilled, yielded at the rate of 288 bushels per acre, 1897— J level, yielded at the rate of 384 bushels per acre, 96 bu. increase. 1898- 1899- hilled, yielded at the rate of 327 bushels per acre, level, yielded at the rate of 345 bushels per acre, 18 bu. increase. hilled, yielded at the rate of 194 bushels per acre, level, yielded at the rate of 241 bushels per acre, 47 bu. increase. Spraying is no more general or thorougli in these two states than in New I^ngland. There are, however, some very worthy exceptions. Two of the most striking that have attracted my at- tention are those of Daniel Dean of Nicliols, N. Y., (Fig. 64) and T. E. Martin of West Rush, N. Y. These gentlemen are firm l)elievers in thorough spraying. They are not satisfied to call their job done when they have sprayed their potato fields, four, six, or even eight times, but have been known to spray as often as sixteen WESTERN NEW YORK AND PENNSYLVANIA 133 times (luring the season. The increased yields t]ie.y secure are, in their Judgment, ample justification for the extra spray material and the labor involved in making so many applications. In all of the strictly commercial sections the crop is harvested with the elevator type of potato digger. ]\Iost of the New York State growers use bushel crates in which to ])ick up and haul the potatoes to the storage house or cellar (Fig. 65). As a rule, neither New York Fig. 65. — Harvesting Sir Walter Raleigh potatoes, T. E. Martin's farm West Rush, N.Y. The potatoes are picked up in bushel crates. Courtesy of T. E. Martin. or Pennsylvania growers have made as ample provision for the storage of the potato crop as have either the Maine growers or those in the "far-west" states such as, Colorado, Utah, and Idaho. The house or barn cellar rather than the special potato storage house is utilized quite generally throughout both states under consideration. The per acre yield in both New York and Pennsylvania is far l)elow what it should be, and what it must be in the near future, when greater demands will be made upon all tillable lands to produce larger supplies of food. The average per acre production of New Y'ork for the years 1915 to 1919 is only 87.1 bushels; and that for Pennsylvania is still less, 82.8 bushels. When it is remembered that Long Island and northern New York, where larger yields are secured, are included in this average, it is evident 134 POTATO PRODUCTION IN NORTH AND WEST that the average yield in western New York is considerably less than the figure mentioned. That yields very largely in excess of these may be grown, when proper cultural care is given to the crop, have been amply proven by Roberts and Clinton,^ in their four reports on potato culture. From these four publications the fol- lowing data on yields secured on the Station farm are presented: 1895 — 352.6 bushels 1896—333.0 bushels 1897—322 bushels 1898—278.0 bushels 1899—202.0 bushels 1900—200 bushels These data are significant in that they furnish conclusive evi- dence of the feasibility of very materially increasing the per acre yield of potatoes, not only in New York State, but in every other state where climate and soil are favorable to the growth of the potato plant. Ohio, Indiana, Illinois, Iowa, and Missouri. — These five states represent the central portion of the geographical area included in the Bureau of Crop Estimates division known as the North and Average Acreage Production and Yield Per Acre and Principal Varieties Groicn— 1915-1919. State Rank in pro- duction Acreage Yield in bushels Bushels per acre Principal varieties grown Ohio.... Illinois. . Iowa Missouri Indiana. 8 10 11 10 19 152,600 137,000 130,800 98,200 82,600 12,027,200 10,715,800 10,566,000 6,926,400 6,521,000 78.2 78.0 80.0 70.2 78.2 Early Ohio, Green Mountain, Rural Early Ohio, Early Michigan, Rural Rural, Green Mountain, Early Ohio, Bur- bank. Irish Cobbler Early Ohio Rural, Green Mountain, Early Ohio, Irish Cobbler West. While none of the five are large producers of potatoes, as compared with the six leading states of this division, they never- theless are, as will be noted in the above table, well up in the list, ranking between eight and nineteen, inclusive. A study of the yield per acre column shows that three of the five states are iden- tical, 78.2 bushels, while the Iowa average is 80 bushels and Mis- souri only 70.2. It is evident, therefore, that the general climatic and soil conditions must be more or less similar. OHIO, INDIANA, ILLINOIS, IOWA, AND MISSOURI 135 Production Centres. — The chief producing centres in Ohio are, according to Ballon,- the counties of Portage, Wayne, Medina, Cuyahoga, Hamilton, Stark, Lucas, Summit, Erie, and Mahoning. He further states that, if the state be roughly divided into four quarters, it would be found that the northeastern quarter produced over one half the total crop of the state. In Illinois, the chief centres are located in Cook, Saint Clair, Madison, Whiteside, and Winnebago Counties. In Iowa, the leading counties are Grundy, Scott, Tama, Marshall, Mitchell and Pottawattamie. The Missouri centres of production, so far as counties are concerned, are St. Louis, Bay, Buchanan, Jackson, and Andrew, Those of Indiana are La Porte, St. Joseph, Allen, and Elkhart. Cultural Practices. — Relatively little commercial fertilizer is used in the production of potatoes throughout these five states. In northern Ohio, according to Green,^ the first two weeks in May is considered the most suitable time to plant. In northern Indiana, Illinois, and Iowa, the planting date for the late crop is similar to that of Ohio. Potatoes intended for early market might be planted considerably earlier. The planting date in the southern portion of these three states is at least three weeks earlier. In Missouri, the planting date in the northern portion is similar to that of the southern part of the preceding states, while in the southern portion, the planting date is advanced to March. In fact, in some localities, Essex, for example, the growing season is suffi- ciently long to permit of growing a second crop. In such c;ases, the early crop may be planted the latter part of February. Modern machinery is generally used in planting, cultivating, and harvesting the crop. Level culture, rather than ridging, is almost universal. Spraying, except for insect pests, is not a general practice. Marl'ets. — With the exception of Ohio and Iowa in years of high production none of these states produce enough potatoes for home consumption; their markets are local rather than foreign, as the crop is, theoretically at least, entirely consumed within their own boundaries. It is quite probable that this group of states will continue to depend upon outside sources for a portion of their table stock supply. At present, they are dependent upon outside sources, largely Michigan, Wisconsin, and Minnesota, for a portion of their seed stock, and the probability is that still greater depen- dence will be placed upon these states. 136 POTATO PRODUCTION IN NORTH AND WEST Michigan. Wisconsin, and Minnesota. — This trio of states possess approximately the same climatic and soil conditions. They are large potato producers and are capable of very materially in- creasing their output whenever there is a market for it. In total production, Michigan, Wisconsin, and Minnesota rank second, third, and fourth. Sometimes one or other of them forces New York to take second place. The only widely known potato territory in this group of states is that of the Red Eiver Valley in Minnesota. Other large shipping sections aside from the lied Eiver Valley in Minnesota are Elk Eiver, Princeton, Anoka, etc. In Wisconsin, the central portion of the state including Waupaca, Portage, and Waushara Counties, represented the largest producing centres in 1909, but for the next ten years or more, the commercial potato belt has been constantly moving northward, keeping pace as it were, with the subjugation of the cutover timber lands in not only Wisconsin hut the other two states as Avell. A large portion of this type of land seems to be admirably adapted to clover and pota- toes. In fact, clovers grow so naturally and luxuriantly throughout most of this section that it has been very happily designated "Cloverland." The commercial potato development of the future, in the "Middle West," is almost certain to be very largely centred in "Cloverland." Michigan has no outstanding potato district. Extent of the Crop. — The production of these three states can be more easily comprehended from the data presented in the table which gives the annual yields for the ten years, 1910 to 1919 inclusive. A comparison of these data show that Michigan's average i)ro- duction for the ten-year period is a trifle over 31 million bushels, Wisconsin 29.8, and Minnesota nearly 27 million bushels. The most interesting feature of these data is that of the wide fluctua- tions in yield from year to year with a relatively small fluctuation in acreage. In Michigan, extremely low yields prevailed during the years 1915 and 1916. Wisconsin's low mark came in 1916, while Minnesota shows low yields in 191 and 1916. These low yields were due to unfavorable climatic conditions. Varieties Grown. — The varieties grown in this area are mainly the Irish Cobbler, Early Ohio, and Triumph, for early varieties, and the Green Mountain, Eural, and Eusset Eural, for late. Other varieties, grown to a lesser extent are the Pearl, King, Burbank, MICHIGAN, WISCONSIN, AND MINNESOTA 137 5 > o5coSSSSSS5 k: opo-4ooi>i-wiOh-p r- • i il§§gllgig > 1 oooooooooo OOOOOOOOOO oooooooooo CO 35.175,000 31,020,000 36,750,000 33,600,000 44,044,000 20,945,000 15,360,000 35,910,000 28,560,000 28,688,000 It t s^s^sBsgsi to 11 1 oooooooooo 0*-OCOtOOaiMODO O O CC O p O t;i O O O b b b b b b b b b b p hi oj p p p o to oi o >-' -lb CO lo '-I lo o CO b OOOOi-'CCO'-IMO p p O O p O O Or Cn Oi b b b b b b b b b b OOOOOOOOOO OOOOOOOOOO o o o o 138 POTATO PRODUCTION IN NORTH AND WEST and Eusset Burbank. The Early Ohio is the most extensively gro^\ai early variety in Minnesota. In Wisconsin, a strong effort is being made to develop a large Triumph seed trade in the South and, as a natural result, Triumph acreage is on the increase. Michigan has no very well developed seed trade, and is not exten- sively engaged in the production of early potatoes, except to supply local markets. Cultural Practices. — The cultural practices in vogue in Michi- gan, Wisconsin, and Minnesota do not differ essentially from the central group of states with respect to planting and tillage of the crop. Level culture is practised. As a rule, most growers use too small an amount of seed, 10 to 12 bushels, rather than 15 to 18. In some sections of these states, one still finds growers using the hill instead of drill method of planting potatoes. The rows are usually spaced 36 inches apart and the plants in the row from 24 to 36 inches apart, mostly 30 to 36 inches apart, the field being marked in both directions with a marker, after which it is planted with hand planters. The hill method of culture is usually found on the cheaper and less productive lands, and is largely practised in order to permit of cultivating the crop in both directions with horse implements, thereby doing away with hand labor. North and South Dakota, Nebraska, and Kansas. — These four states are the western tier of the North and West division of 21 states. They are, in reality, the western states of this division. In point of production with other states, they rank as follows: Nebraska 13; North Dakota 17; South Dakota 18; Kansas 25. Eelatively speaking they are not large producers, though as a rule, except possibly in Kansas, they produce more than enough for their own needs. The production by years from 1910 to 1919, as given in the table of this group, shows a very low average yield in Kansas as compared with the other states. Kansas also shows the widest percentage range between the highest and loAvest acre yields. These four states are of interest, aside from their consti- tuting the western tier of states of the North and West division, in that certain sections of all of them can be irrigated. Irrigation plays a more important role in commercial potato production in northwestern Nebraska and southwestern South Dakota than in North Dakota and Kansas. Potato Production Centres. — The chief production districts in NEBRASKA, KANSAS AND THE DAKOTAS 139 ifl lO o o o ■^ •* M to r-;^ OJ ■* U5 (N ■* lO ■* ■V CO IN -^ II ■* t^ o ■^ lO h. ■* 8 § o o lO o II 8 8 8 8 8 8 O ^ (N 140 POTATO PRODl'CTION IN NORTH AND WEST Xpl)raska are in Uw northwestern section, Tlie leading counties are Hcottsblutl', Sheridan, Box Butte, Douglas, and Sioux. During the past two years, the Kearney district has come into considerable prominence as an early market production centre. South Dakota has no well defined area. The leading counties are Brown, Minne- haha, Spink, Brookings, and Day. The IJed Eiver Valley district on the eastern border of Xorth Dakota, with Grand Forks and Larimore as the centre, is the chief commercial potato production centre of that state. The chief producing centre in Kansas is the Kansas or Kaw Eiver Valley extending from Kansas City to Topeka. The leading counties are Wyandotte, Johnson, Leaven- worth, Douglas, and Jefferson. Varieties Grown. — The varieties grown in a commercial way are quite similar to those grown in tlic states to tlie East. They are as follows : North Dakota Early Ohio Irish Cobbler Triumph Rural Green Mountain South Dakota Early Ohio Irish Cobbler Triumph Rural Nehi'aska Early Ohio Triumph Pearl Rural Russet Rural Charles Downinji Kansas Early Ohio Irish Cobbler Triumph Ciolcl Coin The Early Ohio is the leading variety in the eastern ])ortion of these four states. The Triumph is of greatest importance in northwestern Nebraska, where i!: is being grown rather extensively for seed purposes on both dry and irrigated land, largely the former. This seed stock finds a ready market in Louisiana, Texas, Okla- homa, Arkansas, and other southern points. Cultural Practices. — Where irrigation is not practised, level cultivation with a slight ridging with last cultivation is the usual method. When grown under irrigation, the ridge culture method becomes a necessity because -it provides the only feasible way of irrigating the crop. The usual distance between the rows is three feet, but in some sections a wider spacing is allowed, this being particularly true under dry land culture. Owing to the almost if not complete absence of the late blight fungus in this region, few, if any, growers practise spraying their crop, except with arsenical poisons, as a protection against insect pests. The crop, as a whole, is largely grown for table stock, intended for fall and winter THE FAR-WESTERN STATES 141 consumption and for seed purposes, rather than for the early market. The Early Ohio of the Eed River Valley is marketed for seed purjjoses in eastern Nehraska, Kansas, and points East. The Far-Western States. — The eleven states included in the geographical division known as the Far- Western States are Wy- oming, Colorado, Xew Mexico, Arizona, Nevada, Utah, Montana, Idaho, Oregon, Washington, and California. Of these, California, Colorado and Washington are the largest producers; Arizona and New Mexico the smallest. Colorado has the distinction of being the heaviest shipj^er of potatoes to markets outside of her own borders. In all of these states, potatoes are grown both under irrigation and dry land conditions. In the Pacific Coast states, l^articularly Washington and Oregon, the climatic condition, so far as precipitation is concerned, is very similar to that in the Jiortheastern United States. The data presented in the table of this group show the average acreage yield in bushels, and bushels per acre of each of the far- western states for the years 1910 to 1914, 1915 to 1919, and 1910 to 1919. This summary shows that California leads in production in both five-year periods, but does not lead in bushels per acre. Nevada ranks first in yield per acre, Avith Utah and Idaho close rivals for second place. Too great importance should not, however, be attached to the relative yields per acre in the various states, as this is very largely influenced by the per cent of the acreage that is under irrigation. Take Colorado, for exami)le, where quite a large acreage is grown under dry land conditions, the yields may vary from 50 to 150 bushels per acre. The same seed stock, under average conditions, would produce from 300 to 400 bushels on irrigated land. In fact, yields of over 500 bushels per acre have l)een frequently obtained on rather large acreages, both in Colorado and elsewhere. It is necessary, therefore, to remember, when com- paring yields from one state with those from another, that the only true basis of study is that of comparing the irrigated sections. In the absence of complete data, regarding the actual acreage in each of the far-western states of irrigated and non-irrigated pota- toes, it is not possible to make such comparison. Varieties Grown. — While the list of varieties grown in these states is somewhat larger than is now regarded as good commercial practice, the actual number grown in any given section is not really a large one. 142 POTATO PRODUCTION IN NORTH AND WEST s ^ 1"^ §:§ l-l g l-l; O O O o o o o O OS C5 o t-'f-N)*.CnO!00^_CO 00 0~. to ">«^ H-* ^ lo . ^ pi CO p o CO b M io t» bi 1^1 CO Cn O M 05 l-> Ol H- CO CO CO tt» (-1 jb. oi cn 00 p rf» M i-i W 1 10,652,400 8,593.000 8,441,300 6.377,800 5.147,700 4,928,000 3,058,900 2,302,200 1,778,100 769,200 181, .500 1 in 34.7 21.5 39.3 121.0 60.9 25.1 61.8 23.1 70.9 88.4 86.4 THE FAR-WESTERN STATES 143 The accompanying list of .varieties, submitted for each state, is believed to include most of those that are more generally grown commercially : Arizona. — Triumph. California. — Burbank, Russet Burbank, White Rose, Chas. Downing (Idaho Rural), Early Rose. Colorado. — Pearl, Rural. Russet Burbank. Brown Beauty, Chas. Downing, Perfect Peachblow (Red McClure), Early Ohio, Irish Cobbler. Idaho.— Cha.s. Downing, Rural, Russet Burbank, Early Ohio. Montana. — Rural, Green Mountain, Russet Burbank, Pearl, Irish Cobbler, Triumph, Early Rose, Early Ohio. Nevada. — Rural, Burbank, Russet Burbank, Pearl ( Peerless ) , Perfect Peachblow, Early Ohio. Neic Mexico. — Irish Cobbler. Oregon. — Burbank, Pride of Multnomah, Russet Burbank, White Rose, Early Ohio. Utah. — Chas. Downing, Rural, Russet Burbank. Washingto7i. — Burbank, Russet Burbank, Chas. Downing, Rural, Early Ohio. Wyoming. — Pearl, Chas. Downing, Russet Burbank, King. Produciion Centres. — Generally speaking, the west and far- western states have more clearly defined production centres than in the East. This is due to the fact that a large per cent of the crop is grown under irrigation and is therefore confined to these areas. Colorado. — In Colorado, the potato industry is roughly segre- gated into seven districts known as the Greeley, Divide, North- western, Intermountain, Western Slope, Southwestern, and the San Ijuis Valley. The Greeley district, located in Weld County, is so well known that little need be said regarding it. Until the year 1909, it had always enjoyed the distinction of being the largest production centre in the state, and prior to 1910 was con- sidered the second largest potato-producing section in the United States. In 1909, 10,000 carloads of potatoes were shipped out of the county; and the 1910 census report, based on the 1909 crop, credits Weld County with a production of 5,857,691 bushels, an amount in excess of the total production of seven of the eleven states included in the far-western group. Unfavorable weather conditions, accompanied by a severe epidemic of potato diseases during the years 1910 to 1914, very nearly wiped out the industry commercially. Since 1914, there has been a gradual improvement in conditions, and the district is rapidly coming back into its own as a commercial potato-producing centre. The Divide district includes portions of three counties, Douglas, POTATO PRODUCTION IN NORTH AND WEST COLORADO 145 l^^lbert, and El Paso. It occupies the elevated central section of the "Eastern Slope" of the Eockies. The rainfall of this district, particularly of the more elevated portions which reach an altitude of 7,500 feet, is sufficiently heavy, nearly 20 inches, to permit of growing a crop of potatoes without irrigation. This is made pos- sible by a cool summer climate, which furnishes ideal conditions for the production of good seed potatoes. About 3,000 acres of potatoes are grown in the district. The Nortliivesiern district is of relatively little importance commercially. It includes portions of Moffat and Eoutt Counties, located in the extreme northwestern part of the state. The cli- matic conditions are very similar to those of the Divide section. The Early Ohio and the Eusset Burbank are the leading varieties. The area devoted to potatoes is about 750 acres. The Intermountain disirid is generally referred to as the C'arbondale district, but this is somewhat erroneous, as it also in- cludes the Eagle Eiver district. These are located in Garfield and Eagle Counties, respectively. Owing to the relatively high altitude of the intermountain district, 6,000 feet and above, the climatic conditions are very favoralile to potato production. Both the Eagle and Carbondale districts have an abundant supply of irrigation water drawn from the Eagle and Crystal Elvers. The leading varieties are the Eusset Burbank (Fig. QQ>), Peachblow (Fig. 67), Eural, and Charles Downing. The total area devoted to the potato is about 5,500 acres. The Crystal Eiver Land Company, generally referred to as the Sweet Eanch, has long enjoyed an enviable repu- tation in the production of large per acre yields. The present and former associate proprietors are shown in figures 68 and 69. The Western Slope district embraces the valleys of the Grand, Gunnison, and Uncompagre Eivers, and the adjacent irrigated mesas. Portions of Mesa, Delta, and Montrose Counties are in- cluded in this district. The leading varieties are Irish Cobbler, Charles Downing, People's, Eusset Burbank, and Eural. Over 6,000 acres of potatoes are grown in this territory. The Southwestern district consists of the irrigated valleys and mesas of Montezuma and La Plata Counties. The comparative unimportance of the potato industry of this section is largely due to poor shipping facilities. The soil and climate is well suited to potato production. The leading varieties are Early Ohio, Eus- set Burbank, and Eural. Acreage 2,000. 14G POTATO PRODUCTION IN NORTH AND WEST WYOMING 147 The San Luis Valley district enjoys the distinction of having produced a larger crop of potatoes in 1919 than the Greely district, and there is a possibility of its ultimately becoming the leading production centre in the state. This elevated plain, with altitude at some points exceeding 7,500 feet, is located in the south central portion of the state. The larger portion of the potato-producing section is in Rio Grande County. Most of the area is irrigated. The leading varieties are Brown Beauty, Eusset Burbank, Early Ohio, People's, and Rural. District Shipments. — The accompanying data, furnished by the Bureau of Markets of the United States Department of Agricul- District wi: 1918 1919 Normal estimate* estimate Greely 5,977 cars 5,740 cars 2,500 cars 6,000 cars San Luis Valley 2,948 cars 3,562 cars 4,400 cars 4,000 cars Gunnison Delta , y 2,380 cars 2,498 cars 2,200 cars 2,500 cars and Montrose Carbondale above Glenwood Spgs. S>. . 663 cars 693 cars 525 cars 600 cars on Roaring Fork Eagle above I Glenwood Sp<^s. >■ ■■ ■ 534 cars 463 cars 400 cars 500 cars on Main J Grand Junction 567 cars 516 cars 400 cars 500 ca:rs San Juan 104 cars 46 cars 65 cars 75 cars Moffat 112 cars 64 cars 100 cars 100 cars Miscellaneous Tt Collin^ y ^^^ '^^^^ ^^^ '^^^^ ^^^ ^^^^ ^^^ ^^^^ Dry Land j * Estimated nviniber of cars that would be shipped. 1917 and 1918 data represent actual shipments. ture, gives a fairly good idea of the relative importance of the principal shipping districts for the years 1917, 1918, and 1919. Wyoming. — The potato industry of Wyoming is a relatively small one, and is largely restricted to the irrigated portions of the 148 POTATO PRODUCTION IN NORTH AND WEST state. There are no very large producing centres. The leading counties, as shown by the 1909 census data, were Laramie, Bighorn, Sheridan, Crook, and Carbon, with yields ranging from 203,016 bushels in Laramie County to 64,378 bushels in Carbon County. Torrington, in Goshen Count}', is the centre of one of the more recently developed irrigation areas in Wyoming. The land in the vicinity of Torrington seems to be admirably adapted to the potato. Some fields visited in 1918 promised to yield around 250 sacks (approximately 500 bushels). A considerable acreage of potatoes M'as grown in the Cowley drainage district in Park County in 1!)19, Fifj. CS. — Lou D. Sweet, Carbon- Fig.CQ. — FrankE.Swcct.Carbon- (lale, Col. A well known authority dale, Col. A successful potato grower on potato culture. President of the and former partner of Lou D. Sweet Crystal River Land Co., better known of the Crystal River Land Co. as the Sweet Ranch, on which high yielding cropaofpotatoesare annually produced. and it is claimed that there will be a large increase in 1920, due to the in,stallatioii of a modern dehydration and starch factory at that point. Varieties. — The leading varieties grown in the state are the Pearl, Spaulding Xo. 4 (King), Charles Downing, and the Eusset liurbank (Netted Gem). Montana. — The average total production of ])otatoes in Mon- tana during the teti-year period 1910 to 1919, inclusive, was slightly less than 5 million bushels, with an average acre yield of 125.1 bushels. There are no extensive ])roduction centres. A consid- erable acreage of potatoes is grown in the Flat Mead Lake region. IDAHO 149 Varieties. — The principal varieties grown are Rural New Yorker Xo. 2, Burl)ank, llus.set Burbank, Green Mountain, Pearl, Early Ohio, Triumph, and Irish Col)bler. Idaho. — The potato crop of Idaho slightly excels that of Mon- tana both in total yield and in production per acre. This is prol)ably due to the fact that a larger proportion of Idaho's potato crop is grown under irrigation than that of Montana. The average production for the ten-year period 1910 to 1919 was 5,147,700 bushels, and the average acre yield was 160.9 bushels. Idaho has several distinctive and well recognized production centres. These are in the order of their importance, the Idaho Falls, Burley, Boise (n- Caldwell, Blackfoot, and Twin Falls irrigation sections. In the Idalio Falls district there are large tracts of warm, sandy soils, irrigated with water taken from the Snake River. No at- tempt is made in this section to produce an early market crop. The varieties most largely growni are the Russet Burl^ank and the Rural New Yorker. The Caldwell district on the Boise project is of considerable importance as an early market section. The soil is for the most part a light sandy loam, well adapted to the production of an early crop. The variety grown is the Charles Downing or, as it is more generally known in this section, the Idaho Rural. It is a second-early or mid-season variety, but seems well adapted to its environment in this region. The growers hasten its maturity by withholding irrigation during early July in order to ripen otf the \anes and harden the skin. They begin to dig the crop the latter ])art of July or early August and it should all be marketed before August 25. Owing to a combination of circumstances, some growers sustained rather heavy losses in 1919, due to the scalding of the potatoes in the ground as a result of their not having been marketed soon enough. On September 10, the writer saw one field in which the grower had sorted out fully 50 per cent of the crop, and the other 50 per cent failed to pass inspection as No. 1 stock. Failure to market the crop at the proper time was due to a shortage of refrigerator cars in which to transport the stock, and to the scarcity of labor, thus delaying harvesting operations. The Burley district is the second most imj)ortant potato pro- duction centre in Idaho. The Blachfoot and Twin Falls districts are of much less im- portance from a commercial standpoint. The only drawback to 150 POTATO PRODUCTION IN NORTH AND WEST a large production of potatoes in Idaho is that of its distance from the large consuming centres. Nevada. — Although the State of Nevada produces a compara- tively small crop considering its geographical area, it is relatively large when based upon its population. The average production for the past ten-year period, 1910 to 1919, was 1,778,100 bushels, while the population of the state, as reported in 1915, was 106,734. On this basis, the per capita production was about 16% bushels. When this amount is compared with the per capita production of the leading potato-producing state in the Union of 3.4 bushels, it is seen that Nevada's crop far outranks that of New York State, in point of population at least. Hardman states* that less than 2 per cent of the total cultivated area of the state is devoted to potatoes, and that, of the 900,000 acres of irrigated land, about 15,000, or 1% per cent were devoted to the potato crop. The average production per acre of 170.9 bushels gives Nevada second place among the states of the Union, Maine alone surpassing her in this respect. Principal Poiato Districts. — The principal potato-producing districts, four in number, located in the western portion of the state, are as follows: (1) Truckee valley; (2) the Newlands Ee- clamation Project; (3) the Carson valley; (4) the Mason valley. According to Hardman, large areas of the Newlands Keclamation Project, and the Mason valley are excellently adapted to po- tato culture. Bate of Planting.— The bulk of the crop is planted during the middle of May, and is generally com])leted by the first of June. Varieties. — The principal varieties grown are the Eural New Yorker No. 2, Burbank, Eusset Burbank, Pearl, Early Ohio. Arizona. — The state of Arizona has the distinction of being the tail-ender in potato production. Its average annual production for the ten-year period, 1910 to 1919, is only 181,500 bushels with an average acre yield of 86.4 bushels. Potato production in the state at the present time is on the increase. In fact, the Bureau of Crop Estimates' statistics note an acreage increase of 500 per cent since 1916. A small industry is being developed near Flagstaff, in Coconino County, and Glendale, in Maricopa County. In the southern part of the state, the early crop is planted from January 15 to February 15 ; and the fall crop, from August 20 to September 10. The early crop must be out of the ground before WASHINGTON 151 July 1, as it deteriorates very rapidly with the advent of extremely hot summer weather. The early crop is usually consumed before July 4. New Mexico, — Potato growing in New Mexico is a rather unpromising industry, owing to the many failures that are incurred through the non-development of marketable sized tubers. These failures usually occur in hot dry seasons, aud are, in most cases, probably entirely due to unfavorable climatic conditions. In some cases, fungous diseases inhabiting soils, such as Fusaria and Ehizoctonia, are no doubt responsible for lack of success in produc- ing a profitable crop of potatoes. The annual production during 1910 to 1919 was 7G9,200 bushels with an average yield per acre of 88.4 bushels. The largest production centre is Cloudcroft in Otero County. The Irish Cobbler is the principal early variety. Neither New Mexico nor Arizona are ever likely to become im- portant potato-producing states. Utah. — The State of Utah ranks seventh in point of production among tlie eleven far-western states. Utah, Davis, Salt Lake, Cache, and AVeber Counties are the largest production centres. The average annual production during the period of 1910 to 1919 was 3,058,900 bushels, with an acre yield of 161.8 bushels. The principal varieties grown are tlie Charles Do-\vning (Idaho Eural), Russet Burbank, and Rural New Yorker No. 2. Oregon. — The State of Oregon has two rather distinctive types of climatic conditions, the eastern portion having a jDractically semi-arid climate, while the western portion has a more or less humid one. The average annual production of the state for the years 1910 to 1919 was 6,377,800 bushels with an average acre yield of 121 bushels. The largest production centres are located in Multnomah, Marion, Clackamas, Washington, Lane, and Lin- coln Counties. The leading varieties grown are the Pride of Multnomah (Burbank type), Russet Burbank, White Rose, Early Ohio, Rural New Yorker No. 2 and American Wonder (Burbank type). Washington. — The climatic' conditions in Washington State are very similar to those in Oregon, in that the western portion is humid and the eastern part semi-arid. There are two rather well recognized irrigated sections, the Yakima and Wenatchee Val- leys, which produce considerable quantities of potatoes. The aver- age annual production of the state for 1910 to 1919 was 8,441,300 152 POTATO PRODUCTION IN NORTH AND WEST bushels with an acre yield of 139.3 bushels. The leadiiicj produc- tion centres are located in Yakima, Spokane, Skagit, King, and Whitman Counties. The leading varieties are the Russet Burbank, Charles Downing, Early Ohio, and Rural New Yorker No. 2. California. — The state of California enjoys the distinction of having a greater variety of climatic conditions than any other state in the Union. In the southern portion of the state, it is possible to produce a crop of ])otatoes about as early as in southern Florida; while in the more elevated portions of the northern part, the frost-free season is hardly of sufficient length to permit of maturing a crop. It is not strange, therefore, that many problems confront the California potato grower. In point of production, California leads all others of the far-western states, with an average annual yield for the years 1910 to 1919, of 10,652,400 bushels, and an acre i)roduction of 134.7 bushels. The chief production centres are San Joaquin, Los Angeles, Sacramento, Contra Costa, and Santa Cruz Counties. Of these centres San Joaquin and Los Angeles are the most important. The potato crop in San Joaquin County is produced on the reclaimed "tule" lands in the delta sections of the San Joaquin and Sacramento rivers. First crops on reclaimed lands will frequently run 300 sacks per acre. The sack will average about 115 pounds. In Los Angeles County it is possible to plant potatoes for the early market during January, and to harvest the crop in the latter part of March and early April. A second crop, planted in late July or August, is also grown in this section, and is harvested in November. The Potato King. — The story of the Stockton potato district, San Joaquin County, would not be complete were we to fail to mention the "potato king," of the Pacific Coast, Mr. George Shima, who, not so many years ago, emigrated to California from Japan and became a day laborer on these reclaimed lands. The story of his rise from a day laborer to the largest potato grower and potato operator on the Pacific Coast is one which should thrill every am- bitious American youth. Some years ago, Mr. Shima was growing 8,000 acres of potatoes. The writer was on one tract of 4,400 acres, in the spring of 1910, which was being fitted for planting to potatoes by Shima's crew of laborers. Harvesting the Crop. — The usual method of digging the crop is with a heavy five or six-pronged hoe fork, so constructed as to CALIFORNIA 153 be used in the same manner as a hoe. Each digger picks up the tubers as they are dug. Large and strongly made wicker baskets serve as containers for the tubers. When full, the contents of the basket is transferred to a two-bushel burlap bag. The sacks are well-filled, and the digger usually faces the mouth of the sack with extra large and well shaped tubers. When the market is dull at digging time and the stock grown is sound, it is frequently stored in large piles on the levee and covered with "tule" grass, to protect the tubers from the light frosts that occur in this region during the winter season, and from light. A large proportion of the crop is moved to the market in boats in much the same manner as in the Norfolk district, though the Stockton district is practically all accessible to water. QUESTIONS ON THE TEXT 1. Why does the potato succeed best in the northern part of the temperate zone ? 2. What bearinfj has altitude on potato production? 3. What are the leading potato-producing states? 4. What percentage of the crop is produced by the six leading states? 5. What are the two important factors aft'ecting heavy or light production ? 6. How does the average production per acre of the far-western states compare with that of the six heavy producing states? 7. How does the production of Aroostook County, Maine, compare with the total production of other states? Explain this. 8. What is the general character of the soil of Aroostook County, Maine? 0. What are the leading commercial varieties grown in Maine? Secondary varieties? 10. Is there any similarity between the Long Island, N". Y., and the New Jersey districts? What is it? 11. What are the chief points of differences between these two districts and that of northern Maine? 12. What are the leading varieties grown in these districts? 13. What are the chief producing centres in New Jersey? 14. ^^■hat is the chief ])roduction centre on Long Island, N. Y. ? 13. What is the character of the soil in the more intensive potato-producing areas on Long Island and in New Jersey? 10. How do the climatic conditions of these compare? 17. What is the source of seed supply of these two sections? 18. Do the New England States, Maine excepted, produce any considerable quantity of seed potatoes? Why? 19. Are early varieties grown to any considerable extent in western New York and Pennsylvania? Give reason. 20. What does a comparison of production in these two states for the years 1910 to 1919 show? 21. What varieties are most commonly grown? 22. What did Stone's investigations with level and ridge culture disclose? 23. How do they store their crop of potatoes? 154 POTATO PRODUCTION IN NORTH AND WEST 24. Of what importance are the States of Ohio, Indiana, Illinois, Iowa and Missouri from the production standpoint? 25. Compare their yields per acre with Lon(>■0l00O505Oc»^^^CJl ,- o t- h-o > 00 O N5 C2 ^I O O Or 4^ N3 lO Hi 3- 2; c ■^ ^5 OK mI^ h: ^ CO ^^2 ^^? S !^ ppOM OiOiOOiOtOO^OiMCC S o> v: bbob^Mi^-lbb^f-M "S "^ ^ ^^ > O WON) p OW000 05 ii| 3o lis S" m ggoS OOiNJW OiT-JJSC/'W m §J2 ii »MgW ^2§s K^igsfeS; s§ rf^ b b MOl^ p? pi r p CO 2 --g-p s?° ^£oS Ml—*'- ooimosi-'co PI i§2 a, to oo to 00 8SS^ gsasgg 160 POTATO PRODUCTION COSTS The receipts, other than from ]iotatoos, on these farms averaged less than 8 per cent, and in arriving at the actual cost per bushel or per barrel, A])p deducted this revenue from the total, thereby arriving at a figure which he believes to be quite representative of the production cost of potatoes in Monmouth County, New Jersey. His data shows a cost of 93 cents per barrel or 33 cents per bushel. App's Cost Data. — The ])roduction costs given by App in the following table are, in his Judgment, fairly representative of this section in 1914. They show a total production cost per acre of $85.15, and a total income of $123.48, leaving a net profit of $38.33 per acre. The average ])rice received for the potatoes on these farms was $1.45 per barrel, and the average labor income of these farms was $2,123.00. Acre cost of producing potatoes on 2.7 potato farms in Monmouth Counti/, Nev Jersey. Total acres of potatoes on the 25 farms 919 Labor expense per acre $21.58 Cost of potato seed— 485 bbl 10.76 Fertilizer expense 24.95 Machinery depreciation 2.35 Spraying materials 0.51 Barrels 0.55 Clover crop seed 0.73 Taxes 3.10 Insurance 0.94 Interest 21.72 Grass seed per acre 0.92 Miscellaneous 7.(52 Total acre expenses $95.72 Brought forward $95.72 Receipts from crops other than potatoes, divided by the number of acres of potatoes 10.57 Cost per acre of potatoes $85.15 Yield per acre 92.1 bbl. Cost per barrel 0.92 Cost per bushel 0.33 Fox's Cost Data. — One of the most exhaustive studies upon the cost of producing potatoes that has come to the writer's at- tention is that recently published by Fox,- in which a digest of the cost of producing potatoes on 355 farms in Steuben, 161 in Suffolk, and 41 in Nassau Counties in 1912; 300 in Clinton and FOX'S COST DATA 161 Franklin counties in 1913; and 26 records on 20 cost account farms in 1913, 1914 and 1915, is presented. The following analysis of Fox's tables presents the more salient features of these data. The comparison of costs in the several localities from which his figures Avere secured is very interesting. In studying these data, it is important to bear in mind that these costs were obtained in pre-war times, when the price of labor, fertilizer and all other factors entering into ])otato production were from 50 to 100 per cent less than in 1920. The small amounts of manure and commercial fertilizer used in Steuben, Clinton and Franklin Counties, is due to the fact that relatively few of the 655 farmers involved used either one or the other. The same thing is true with respect to the use of fungicides and insecticides. For example, Fox states that only 180 of the 355 Steuben County farmers sprayed their potatoes, and that Bordeaux mixture was only used on 17 farms. Peacock's (I.e.) data show that 203 of the 300 Clinton and Franklin County farmers sprayed their potatoes with arsenical ])oisons, and only three sprayed with Bordeaux mixture. An interesting feature of these data is that of the wide variation in the average cost of growing an acre of potatoes. Tlie average cost in Steuben County being $51.13, as against $113.51 in Nassau County or an increase of 122 ])er cent. The cost per bushel varied from 37 to 61 cents or a difference of nearly 65 per cent. The significance of these figures is not fully appreciated until they are compared with their selling value. For example, the 355 Steuben County farmers produced potatoes on 5,227.1 acres at an average cost of $0.4201 per bushel ; for which they received a return of $0.4403 per bushel, thereby netting a trifle over two cents per l)ushel, or a total return of $2.46 per acre. The 161 Suffolk County farmers, on their 3,149.7 acres, produced potatoes at an average cost of $0.5426 per bushel; for which they received a return of $0.7055 or a net profit of $0.1629. The total return per acre was $25.66. Nassau County growers, of whom there were 41 with an aggregate of 1,466.3 acres, grew potatoes at an average cost of $0,607 per bushel; for which they received a return of $0.7495, or a net profit of $0.1425 and a total return of $26.66. The 300 CUnton and Franklin County growers, on 2,160 acres, produced potatoes at an average cost of $0.3898 ; for which they received a return of $0.5784 per bushel, or a net total profit of $36.29 per acre. The average of the 26 records, from the 20 cost account farms. 1G2 POTATO PRODUCTION COSTS showed an actual cost of $0.4202 per bushel, witli returns of $0.5158; or a net profit of $0.0956 per bushel, ami u total profit of $7.92 per acre. One of the most important economic lessons to be deducted from these data is that it was more profitable for the Nassau County farmers to produce potatoes at a cost of nearly 61 cents per bushel, than it was for the Steuben growers at 42 cents. This was made possible through the wide difference in price received for their crop by these two groups of growers. Had the Nassau growers been compelled to dispose of their crop at the same price as that received by the Steuben growers, they would have sustained an actual loss of $34.95 per acre, instead of realizing, as they did, a profit of $26.66, It is obvious from these data that low cost of production is not necessarily correlated with a large net profit per acre. Proximity to large consuming centres, where advantage can be taken of a strong market, may make potato production a more profitable undertaking, even at a greatly increased cost per bushel, than in a remote-from-market section, where the grower is more or less dependent upon local buyers for the disposal of his croi>. Pelton's Cost Data. — At a meeting of the Connecticut Vege- table Growers Association, in February, 1918, some cost figures on potato production, based on rather small areas, were presented by Pelton;-* in which it was shown that, under Connecticut condi- tions, the cost of growing potatoes was greater on very small areas than on larger ones. Three sets of cost data were submitted, one being based on a half acre, another on one acre and the third on nine acres. These data, as assembled in the next table, show that it cost $132.16 to grow half an acre, or at the rate of $264.32 i)er acre; $171.55 for an acre; and $166.55 on a nine-acre basis. Strik- ing variations in the cost of the same item in the three sets of data may be noted in this table. For example, in the digging and storing of the crop, the cost varies from $20.00 per acre on the nine-acre field to $46.50 on the acre field and $31.24 on the half acre, or at the rate of $62.48 per acre. These figures are interesting in that they illustrate very forcibly the impossibility of producing potatoes cheaply on small areas where, of necessity, much of the labor must be performed by hand. It also emphasizes the fact that the small grower cannot success- fully compete with the large grower, provided the latter uses NORDMAN'S COST DATA 163 modern machinery and handles his crop intelligently. Potato pro- duction on a small acreage basis with a large amount of man labor is only justifiable where the crop is primarily grown for family use, or where nearby markets absorb it at practically retail prices. Nordman's Cost Data. — A rather recent article by Nordman^ contains some interesting information upon the cost of potato Cost of Potato Production in Connecticut in 1917, by W. C. Pelton. Cost factors One-half acre fielc One-acre field Nine-acre field Fitting land $ 6.20 $ 10.40 $ 10.00 per a. Planting & cost of seed .... 61.60 06.50 per a. Seed at $2.90 and hauling seed at $0.88 15.38 Cutting seed 1.64 Labor in planting ... 3.48 Fertilizer & manure 31.00 40.05 per a. Ten loads manure 10.00 Hauling manure & spread- ing by hand 42.68 Cultivation & hoeing 4.48 13.85 15.00 per a. 1 65 8.20 15.00 per a. Digging & storing 15.62 46.50 20.00 per a. Marketing 13.23 Interest on valuation ($400.00 per acre) .... 12.00 Overhead expense and .... taxes 5.80 Total cost .... $132 16 $171 55 $166 55 Yield 150 bu. 170 bu production in Wisconsin. At a hearing in Milwaukee, on April 23, 1920, conducted by the Wisconsin Division of Markets, the testimony given by potato growers on the cost of growing potatoes in 1919, showed a wide range of variation. The lowest estimated cost was 56 cents per bushel, while the highest was $2.57 per bushel. In the latter case, the high production cost was due to the yield, which was cut dowai to 30 bushels per acre as a result of unfavorable crop conditions. The average cost per bushel of those testifying was 78 cents per bushel. 164 POTATO PRODUCTION COSTS The low cost of production, 5G cents per bushel, was reported by one of the best growers in the state, whose average production per acre was 250 bushels. It must be evident to the reader, from even the limited amount of data presented, that cost of production is directly correlated with yields ; and that yields per acre are largely dependent upon the skill and intelligence of the grower. In certain secti,ons of the country, where the soil and climatic conditions are favorable and the land well supplied with plant food, the skilful grower will inevitably produce a crop of potatoes at a much lower cost ])er bushel than will some other grower, equally skilful, who attempts to grow potatoes under less favorable soil and climatic conditions. I am firmly convinced that the only solution of the present high cost of produc- tion is that of increasing the yield per acre through the use of high grade seed, and the adoption of up-to-date methods of cul- ture, harvesting, and marketing of the crop. When the average })roduction of some of our largest producing states is raised to 150 or 200 bushels per acre, instead of from 85 to 95 as at present, the question of cost per bushel and net returns per acre will have been satisfactorily solved. QUESTIONS ON THE TEXT 1. Upon what two factors is the successful conduct of any nnnnifaoturing enterprise largely dependent ? 2. Why does it require as high a degree of intelligence to produce a good crop of potatoes, as in the manufacture of potato machinery? 3. Why does the mere statement that it costs $175.00 to grow an acre of potatoes mean so little? 4. How may we arrive at a proper and fair basis in the jjroduction of potatoes ? 5. What are the cost factors involved? (i What items should be charged against the crop for labor? 7. What should be included under materials? S. On what should interest chai'ges against the crop be based? !». What are the legitimate insurance charges? 10. On what should a tax charge be levied? 1 1 . How shoiild depreciation be estimated ? ]•! Discuss overhead charges. l.S. What is meant by risk? 14. What charges should be included under miscellaneous items? If). Why is it impossible to give a set of cost data which could be regarded as standard for the whole country? 16. Explain App's method of arriving at the cost of producing potatoes on some New Jersey farms. 17. According to App's data, what did it cost these growers to produce a bushel of potatoes. REFERENCES CITED 165 IS. What was the total production cost per acre, and the net income from same ? 19. What was the average price received per barrel by these growers? 20. What was the average labor income from these farms? 21. What variations do the data from different portions of New York' State show? 22. How do Steuben County data compare with those of Nassau County? 2:5. What is the chief item of difference? 24. Comi>are the per bushel cost in Steuben and Nassau Counties and explain reason why Nassau growers obtained a larger net income per acre. 25. Give reasons for better showing made by Clinton and Franklin County growers than by those from other sections. 26. What correlation is shown by the data between production cost per bushel and net profit per acre? 27. What is the real determining factor governing net profit in the data presented ? 28. What would have happened to the Nassau County growers had they been obliged to sell their crop for the same price as the Steuben County growers ? 29. What is the chief lesson to be derived from Pelton's data? 80. What did the Milwaukee hearing on potato production costs in Wisconsin in 1920 reveal? Give variation in cost of producing a bushel of potatoes. .31. What were the explanations given for the high and low production costs ? .')2. How can we reduce production costs? What is the urgent necessity for doing so? QUESTIONS SUGGESTED BY THE TEXT 1. To what extent do local growers make use of the business principles given here? 2. What are the local costs per acre and per bushel? 3. From the list of cost factors, make a set of questions that will help determine the cost per bushel on a given farm. 4. Use this questionary on a few of the leading farms. 5. How do these results compare with those given in this chapter? 6. What difficulties are encountered in filling such a questionary? References Cited 1. Aw, F. 1916. Farm profits and factors influencing farm profits on 370 i^otato farms in Monmouth County, New Jersey. N. J. »S'fa. liul. 294: 1-103, April, 1916. 2. Fox, D. S. 1919. An analysis of the costs of growing potatoes. X. Y. (Cornell) Hta. Memoir 22: 553-627, May, 1919. 3. NoBDMAN, E. 1920. Cost and profit in potatoes to the farmer. Clover- land Mag. July, 1920: 9 4. Pelton, W. C. 1918. Cost of potato production in 1917. Ann. Rat. Conn. Veg. Gr. Assn. April, 1918: 18-23. CHAPTER XTF HARVESTING, PICKING AND HANDLING- GRADING, SHIPPING AND MARKETING THE POTATO CROP Harvesting the Crop. — The harvesting of the potato crop is generally regarded as the most laborious process involved in the (growing of this most important vegetable. In some sections of the North, as in the northern part of Maine, Michigan, Wisconsin and Minnesota it is also regarded as the most critical operation of the season, on account of the ever-present possibility of unfavorable weather, chiefly rains, delaying the work and tliereby exposing the crop to injury from freezing. The factors to be considered in har- vesting the potato crop are: (1) Date of harvesting; (2) imple- ments used; (3) containers used; and (4) method of handling the crop. Date of Harvesting. — The date of harvesting the potato crop is very largely governed by the character of the crop and the locality in which it is grown. By the character of the crop is meant whether it is grown as an early or a late crop. The date is also further determined by the market demand and the selling price. For example, the early truck crop of the South is very rarely allowed to reach full maturity before being harvested. Harvesting operations usually begin as soon as the yield of marketable potatoes justifies the grower in sacrificing yield for the sake of securing the higher price which usually prevails in the early part of the season. On the other hand, the late or main crop of the North is usually allowed to remain in the ground until the plants are fully ripe or nntil the early frosts have killed them. In short crop seasons, high prices and an active demand induce many a grower of late potatoes to harvest his crop before it is ripe, in order to take advantage of the prevailing prices. It is thus seen that the date of harvesting does not necessarily represent any fixed stage of maturity of the potato crop. As the southern crop is only allowed to reach maturity, before being harvested, in seasons when the price is considered too low to justify digging and marketing it, we may consider that the usual time of harvesting is when the crop is still immature, but of sufficient size to give a fair yield. In the North, 166 HAND IMPLEMENTS 167 ou the other hand, the customary practice is to allow the crop to mature — weather conditions, of course, permitting. Harvesting Implements and Their Operation. — The imple- ments that are used in harvesting the i)otato crop may he conveni- ently classified into two groups: (1) hand implements; (3) horse implements. Hand Implements. — The hand implements are the ordinary hoe; the pronged or tined hoe (Figs. 70 and 71), spading fork. pstinK potatoes in the old fashioned way. Hill selection is possible wiicii ihu Liui^ iB dug in tins manner. six tined manure fork and a specially constructed hand digger, with a lever attachment in the rear which enables the operator to pry instead of lift the plant, with its tubers, out of the soil. Har- vesting a potato crop with any of these implements is a slow and laborious process, and is only practised where relatively small areas are grown for family use. In the earlier days, before the develop- ment and perfection of the horse-drawn digger, men became expert in the use of hand operated implements, and rather exceptional individual performances are on record. Expert hand diggers have been known to dig and pick up 100 or more bushels of potatoes in a day. With any of these implements, a careful digger can harvest the crop with a minimum amount of injury to the tubers; but let 168 HARVESTING AXD MARKETING THE CROP the same instruments be used by a careless workman, and from 50 to 15 per cent of the crop will be injured in removing the tubers from tlie soil. Horse Implements and Their Use. — Many varieties of horse drawn implements are now being used in the harvesting of the potato crop. These may be roughly divided into two classes : the non-elevator, and the elevator implements. Non-elevator Implements. — The first class may be divided into four groups: (1) the ordinary one or two-horse plow; (2) Fig. 71. — Harvesting potatoes by hand iu the tule lands near Stockton, Calif. The potatoes are gathered as dug. especially constructed diggers with rigid finger-like attachment to sejiarate the tubers from the soil (Fig. 7^2); (3) similar imple- ments to class 2 except that the finger-like attachment is agitated by a sprocket wheel, thus insuring a better separation of the tubers from the soil (Fig. 73) ; and (4) the light drawn potato digger, with revolving fork-like attachment in the rear, which throws the potatoes and soil raised by the shovel point to one side. The sep- aration of the tubers from the soil is supposed to be accomplished l)y this operation. The Ordinary Plow. — While the one or two-horse plow cannot in any sense be regarded as a potato digger, it has been and still is a rather commonly employed implement in harvesting the early or truck crop of potatoes in tlie Soutli. The ])otato rows are plowed out by turning as light a furrow as possible without cut- ting tlio lower tubers with the jtlow ])oint (Fig. 71). After the POTATO DIGGERS 169 potato plants are plowed out in this manner, the furrow is gone over by the laborers, usually women and children, for the purpose of removing the tubers from the soil and throwing them into small piles (Fig. 75). This operation is commonly known as grabbling potatoes. Usually the tubers from two rows are thrown together. They are then gathered into containers. This method of harvest- ing the southern crop was quite generally practised throughout the South prior to the \Yorld War. The scarcity and high price of labor, as a result of war conditions, virtually forced the southern grower to adoi)t the more modern and labor saving elevator ty])e digger. It is questionable whether, with the return of cheaper labor, the former methods of liarvesting the crop will be resumed. In many sections modern machinery will per- manently supplant the plow, and thus eliminate the slow and costly practice of grab- bling the potatoes from the soil. Fig. 72.— The Erlipse dipper with ri^ia nnis Tj , , TN" J to .separate the tubers from the soil. Potato Diggers 2 and 3. — . The types of diggers given as classes 2 and 3 above are of plow-like construction except that the mold-board is replaced by finger-like iron rods arranged like an arc of a circle (Fig. 76). The plow point l)asses directly beneath the plants, and the soil and plants are forced up over the iron rods. The separation of the tubers is supposed to take place by the soil dropping through the fingers as it is forced back. Class 2 implements with the rigid rods do not separate the tubers from the soil as completely and satisfactorily as do those in class 3. Either implement gives better results in a sandy or light loamy soil than in a heavy one, or on a dry rather than a wet soil. They are a desirable substitute for the ordinary plow and, where small acreages are involved or where the soil is full of small stones, may prove more satisfactory than the more expensive elevator type of digger. Im])lements of this type, when intelligently operated, will cause but little injury to the tubers as compared with the elevator type. Potato Digger No. 4. — Diggers of this class are not generally used in the United States. That they are used is evident from the fact that they are manufactured. It is not possible here to discuss their merits or demerits. From the construction and general ap- 170 HARVESTING AND MARKETING THE CROP pearaiice of the machine, (Fig. 7T), one can readily believe that, in a loose soil, it could be operated very successfully. It is evident that the tractive power required to operate such a machine should be less than for the heavier elevator type of digger. Elevator Potato Diggers, — The elevator type of potato digger is, with but few exceptions, quite generally used in the strictly commercial production centres of the North and West, and is grad- ually coming into general use in the South. There are many makes of diggers, and each manufacturer claims' special features of superiority for his particular machine. It is doubtful if one would be justified in naming any j)articular make of machine as being superior to all others. There are, however, certain outstanding features of dif- ference in construction which may be noted. According to these differences, elevator dig- gers may be separated into five classes as follows: (1) wheeiUhi„'dt7stare\S?iSrr[h:Xr^Th1 Thosc with forward truck at- two lead wheels straddle the row. tachcd to the pole (Fig. 78) ; (2) those with truck attached to the iron frame of the machine (Fig. 79); (3) those with conveyor, and rack head (Fig. 78); (4) those with a second conveyor in place of rack head (Fig. 81) ; and (5) those having a picker attachment (Fig. 78). There are doubtless many other features of difference which, while not so apparent, might well be considered as constituting a separate class or type. Operation of the Elevator Digger. — The tractive power re- quired to operate the elevator type of digger varies with the character of the soil and the method of culture practised. In Aroos- took County, Maine, where ridging is practised and the soil for the most part is light and porous, it is seldom that one sees more than two horses being used to operate the digger (Fig. 80). In the Middle West, where level culture is practised, three and four horses are required (Fig. 82). The same number of horses are also neces- sary in the irrigated sections of the West. To leave the impression that the elevator digger can only be operated by horses would be misleading, because the tractor is now being quite freely used in some sections to haul the digger, and its SUCCESSFUL OPERATION OF POTATO DIGGER 171 further use for this purpose is almost certain to increase. The caterpillar type of tractor seems to be well adapted to this purpose, (Fig. 83), thougli possibly it would hardly be justifiable to claim that it was actually superior to other makes. Within the past few years, elevator digger manufacturers have added a gasoline engine to the equipment of some of their diggers (Figs. 78 and ?!)). The .tK^.'.* Fig. 74. — Plowing out tiie [xitato crop with it turniii'-' i)luw, A coiiinion nietliod of harvesting potatoes in the South. engine is mounted over the conveyor and is designed to operate the conveyor, kicker and rear rack vine and tuljer separator. This relieves the horses of the tractive power required to operate these several parts, which, in the absence of the gasoline engine, are operated by being geared to the wheels of the digger. With the gasoline engine functioning properly, the horses have only to exert the necessary power to haul the machine, and at the same time force its shovel point beneath the potato tubers and push soil and tubers on the conveyor. The successful operation of a potato digger involves several points, the careful observance of which will guarantee the removal of the crop with a minimum amount of mechanically injured tubers. The operator has much to do with the efficiency of any 172 HAR\'ESTIXCJ AND MAliKKTIXO TlIK C^ROr make of machine as regards the ])er cent of injured tubers and the thoroughness of the Avork in general. This may be illustrated by mention of the following point. The shovel point of the digger should be so adjusted as to go deep enough to avoid cutting the tubers. It is almost equally important, on the other hand, to not go any dee])er than is necessary, so as to avoid increasing the drauglit, as well as tlic overtaxing of the conveyor. os])ecially if ( 1 IMi^ I tl \ H 1 tubci^ after the row liii> I... I, |,I,.u,,l Mill with a V labuuuLi^ Hi I 1 ilhn n)^ll> operation the soil is heavy or a little wet. The clogging of the conveyor is a source of annoyance to the operator and a direct loss of time to the owner. In light soils and where the vines have thoroughly ripened, it is sometimes a good plan to go somewhat deeper than is necessary in order to prevent undue injury to the tubers 1)y the soil sifting through the conveyor chain too quickly, thus permitting the tubers to travel over a large portion of the bare conveyor. By attention to this detail, and the removal of a portion or all of the conveyor agitators, much surface injury may be avoided. Another prolific SUCCESSFUL OPERATION OF POTATO DIGGER 173 source of injury is that of driving the machine too fast. This often causes an unnecessary amount of agitation. The author has per- sonally observed four diggers at work in a potato field on sandy soil, where the horses were frequently allowed to break into a slow trot. At such times, the potato tubers Avould frequently bound from the conveyor to a height of eighteen inches or more. In heavy soils and wliere the vines are heavy, fast driving seems to lessen the amount of clogging; consequently, the operator is often Fig. 70. — Digger with typical shovel point and arc-formed tines, and two guide wheels in front. tempted to drive faster than is necessary. When the digger is equipped with a gasoline engine it is possible to drive slower; since the speed at which the conveyor moves can be regulated at will by the operator. Mechanical injury of the tubers may be still further lessened by lowering the rear rack or conveyor, as the case may be, to a ])oint where the drop of the tubers from the digger to the ground will be so slight as to cause little, if any, injury (Fig. 84). When properly adjusted, the elevator type of digger should deliver the vines at one side of the row and the tubers in the centre. Some makes of machines do this more effectively than others, chiefly on account of a slightly different arrangement 174 HARVESTING AND M.UIKETIXG TPIE CROP and curve of the vine aud tuber rear rack rods. A machine oper- ated at au even rate of speed will always do more effective work than when jerky or varying speed movements are permitted. Under favorable conditions, the elevator digger will dig from three to four acres per day. Picking and Handling the Tubers. — In different sections of Fig. 77. — A light draught potato digger with revolving fork-like attachment in the rear, which throws the potatoes and soil to one side of the row. the country, varying practices prevail in regard to the picking aud handling of the newly dug tubers. The early crop in the South, for example, is generally graded as it is picked, and is at once put into the containers in which it is to be shipped to market. When the weather is hot, the potatoes should be gathered as quickly as possible after they are dug, as they are easily injured by the hot sun. In very warm weather, the more careful and experienced southern growers aim to dig in the late afternoon, leaving many PICKING AND HANDLING THE TUBERS 175 lying on the ground over night to be gatliered early in the morning when they are well cooled oil'. It is always advisable to liaul the crop out of the field as soon as convenient after it has been sacked or barrelled. The soiitherri grower uses baskets, buckets, hampers and crates in picking up potatoes (Figs. 90 and 91). In Maine, the potatoes are usually gathered into splint baskets with a strong wooden bale (Fig. 84). The tubers are transferred from the basket to the barrel and in general the transfer is not made U>^ Fig. 78. — Combined potato digger and picker. in as gentle a manner as could 1)e desired. The quick dumping of a basket of potatoes into an empty barrel inevitably injures the surface of many of the tubers. Much injury could be avoided by tipping the barrel, when emptying the first two or three baskets; or by lowering the basket into the barrel before emptying it. They are hauled in the unheaded barrel from the field to the shipping station or the home storage house as the case may be (Fig. 84). In New Jersey, some of the early crop is gathered into five- eighth bushel splint baskets (Fig. 85), in which they are hauled direct to market, or to the sizer if they are to be graded and shipped in sacks. The American Giant Crop of Monmouth County, New Jersey, is gathered into baskets from whence it is emptied into sacks. This crop, like the early Irish Cobbler crop, is gen- erally hauled direct from the field to the shipping station. The grading is done by the pickers as they gather the crop, or the tubers are run over a sizer in the field or loading station. 176 HAR^T^STINO AND MARKETING THE CROP /// Wc.slcni iVr//' Yuii<\ ami in some sections of the ]\Iiddk; West, the potato cro]i is ^i;ath('i'(Ml into wooden Ijoxes or crates holding a hushel (Fig. .Sii), in which tliey aic liauled I'rom the lield to the storage house, cellar, or shi[)i)ing station. In the West, and in some sections of the South, a large part of the crop is gathered in wire baskets by .the pickers, and transferred to two bushel sacks if the crop is to be stored. If it is Ijeing niai'keted as dug it is Fig. 79. — By the aid of the gasoline eiiuiiie to operate the eonveyor belt, vino kifker and vine and tuber separating rod racks, the traction necessary to haul the digger is reduced to a point where two horses can easily handle it. Note low position of tuber rod rack. When lowered in this manner the drop is so slight that it does not injure the tubers. Courtesy of Bateman Mfg. Co. usually graded in the field (Fig. 85). Careful growers cover tlie inside of the wire basket with burlap to prevent tuber injury. When stored on the farm, the pickers empty three half-bushel baskets into each sack. The sacks are hauled to the storage house without being tied, and are emptied directly into tlie storage bin. In ihe tide lands of the Stockton, California district, where it is claimed the digger cannot be successfully operated, the crop is dug by hand. Each workman has his own basket and gathers the tubers as he digs them. GRADING 177 Cost of Picking Potatoes. — The wages ])ai(l to potato pickers have advanced so rapidly (hiring the past few years that it is difficult to give accurate cost data on the gathering of the potato crop. In Aroostook County, Maine, prior to 1914, it was custom- ary for the grower to pay })ickers from G to 8 cents a harrel and board. Day lielp received from $3.00 to $3.50 per day and board in the early part of tlie digging season, and from $3.50 to $3.00 toward its close. The prices paid in the same locality in 1930 Avere from 15 to IG cents a barrel and board, or 1 7 to 18 cents without board. Day lal)or started at $5.00 ]ier day and board, and wound np at $6.00 to $7.00 per day. Expert Maine potato pickers, when the yield is good, have been known to pick as liigh as 135 barrels in a day. A few men, under favorable conditions, will aver- age 100 or more barrels. The average picker will pick about GO barrels per day. In the Red Eiver Valley, pre-war prices were about four cents a bushel. In the Norfolk, Virginia, r.o. so -Thiseievat-., ,„.,, ,.i„, „..,„. into sizes, running from .") to 4, 4 to G, G to 8, 8 to 10, 10 to 1'3, etc., ounces and ])ut in heavy pai)er carton packages of 10, 15, and 20 or more pounds in weight (Fig. 94). Heavy manila paper bags may be sul)stituted for the carton boxes. The housewife who desired boiling potatoes could make use of either of the first two sizes. If bakers were desired, tlie G to 8, or 8 to 10 ounce tuber sizes would be found to meet lier requirements. The larger sizes Avould be found more economi- cal for frying, potato chips, etc. The advantage of having potatoes of a certain size is that they "wall all cook in about the same time, and with a little experience, the time required to cook a given size can be quite accurately determined. These are some of the INJURY TO TUBERS IN GRADING 189 advantages from llie housewife's standpoint; but a number of others might W giv<'n, such as the advantage and convenience to the retailor of li;iii'>-»i no- onr? ■|Vr^rL-o+ near Oaley, Va. Note size of load, also that the.v are snipping anO MaFKet- all stave barrels. Few if any splint barrels are used 'mg; The '>hil)Dino' aild ill the Eastern Shore district. &' _ ^ 11 n marketing of potatoes in a successful and businesslike manner calls for an entirely different kind of experience or ability from that possessed by the average grower. Some of the best potato growers are a sad failure when it comes to the business end of slii|)])ing and salesmanship. It should be borne in mind, too, that when distant markets have to be sought in the disposal of the crop it is often impossible or impracticable for the grower to dispose of his own crop, unless he is fortunate enough to have selected a good commission house to which he can consign it. There is still another factor involved in the marketing of an individual's crop, especially for the south- ern truck grower, who must always ship to a distant market, and that is that, unless he is a large grower, he is unable to load a car inside of twenty-four hours as it is usually desirable to do. Containers. — The first consideration in the shijiping and mar- CONTAINERS 193 ketiiig of the crop is the container in which it is to he packed for shipment. As the appearance of the package or container has much to do with the successful marketing of the crop it is important that the potatoes be put up in clean and attractive containers. The types of containers used the country over in marketing pota- toes named in the order of their widest use are the burlap sack of 100, 120, 150 and 165 pounds capacity; stave and splint barrels, with burlap cover (Figs. 95 to 100) ; the double-headed stave barrel; the hamper of varying » capacity usually 50 pounds; and the five-eighth bushel peach basket (Fig. 101). Large quantities of northern grown stock, especially in the early autumn, are marketed in bulk. The double-headed barrel is, so far ||v^ as the writer is informed, used only in Florida, and most largely in the Hast- ings district. When well ventilated double-headed barrels are properly filled with bright, well-graded stock, headed and neatly stencilled, they present the most attractive appear- ance of any potato container used, (Figs. 87 and 88) ; and, when opened, Fig- 96.— The Beaufort s.c. type ,1 , , 1 11 1 J • • of splint barrel with inner set of hoops tne potatoes snow the least injury which impart a considerable degree of from handling. rigidity to the barrel. Two reasons might be advanced for the double-headed barrel not being more generally used by southern truck growers, the first being the cost, and the second, the additional labor involved in head- ing the barrels. Prior to the war, the double-headed barrel cost the grower in the neighborhood of 36 cents. In 1918 they cost from 70 to 85 cents, and were not oljtainable in suiBcient quantity to meet the demands. The pre-war price for splint barrels was 18 cents, and 22 to 24 for the stave barrel. The use of new burlap sacls with an attractive brand (Fig. 102) gives a more presentable appearance to the package; and the stock usually sells at a sufficient premium above the average to pay the grower handsomely for his additional investment. One of the crying needs of the day is a standard size of sack. All things considered, the two-bushel or 120-pound sack comes lU HARVESTING AND MARKETING THE CROP nearest to being the ideal size. It makes a neat and attractive package if properly filled and sewed up, and is not so heavy as to be lunneldy. The 150- and 165-pound sacks are rather heavy to handle, and are more apt to become slack in handling. A properly filled sack should be so firm, -wlien sewed up, as to handle like a stick of cordwood. Such a package will show k"~s tuber injury from hand- ling than will be found in a ^lack package. A further objection to the use of various sizes of .^.icks is the confusion it tauses in the minds of those \v h o a 1 1 e m p t to keep informed on the market quotations. Unless one is familiar with the practices in vogue in different sec- tions, one cannot be certain w liether the price given is lor a two, two and one-half, or two and three-quarter bushel sack unless it is specifically stated in the report. The liamper is chiefly used in southern Florida and in southern Texas. Just why the hamper is the container most favored in these sections is rather difficult to answer. The five-sixth bushel hamper and the half- barrel hamper being almost universally used in these sections for the shipment of string beans, green peas and other truck crops, the grower has become accustomed to handling them (Fig. 101). The high price received for the new potatoes is also a very impor- tant factor to be considered. The sum of $5.00 or $(5.00 for a 50-pound hamper of potatoes does not seem so staggering to the consumer as would $10.50 to $19.80 a barrel. The five-eiglilh husltel hasJcet used by some New Jersey growers in marketing their early crop of Irish Coblilers is employed only where nearby markets are to be supplied. (Fig. 85.) Fiii. 97.— A \vell-«iaded and u.ll-lillfd barrel of potatoes ready to Ije covered with burlap top. This stave barrel is properly ventilated. SHIPPING POTATOES 195 Shipping Potatoes. — The shipping of potatoes to distant mar- kets involves some knowledge of the proper loading of the car or the boat in which the shipment is to be placed. The question of the proper method of loading cars, and the type of car best suited for the purpose has been quite thoroughly discussed by More and Borland,^ Bird and Grimes/ and Grimes.- As a result of these men's studies and the information they have published on the subject, there has been a very considerable decrease in the losses sustained through overheating in late spring and summer shipments, and from frosting during cold periods in the Winter. The proper way to load a car with barrels is to lay the barrels on their sides; begin the first layer of barrels at one end of the car, placing the first against the side of the car, while the next two are placed end to end to eadi other. The second tier should In staggered with the first (Fig. 103). It is not advisable to place more i > ■ '^*^- ii't^^ t^p Loop is removed ,- ., .. /.ii.n fr""' t''C barrtl then the burlap cover is than three tiers Ot barrels m the spread over and the hoop pressed down SI J. ,1 1 . into place over the burlap and well nailed, ummer or hot weather ship- ments will not permit of as heavy loading as can be safely practised during the cooler autumn and winter weather. The burlap-covered barrel cannot be safely loaded on its side or bilge, as the upper end of the barrel would not sustain the weight of two or more barrels on top of it. Such containers carry best by standing the first tier of barrels on their ends, and placing one tier of barrels on their sides upon tlie first tier as it is being placed (Fig. 104). In the summer shipment of potatoes in sacks, it is not ad- visable to pile them in solid tiers as is done in fall and winter shipments. Grimes recommends (I.e. p. 13) "the placing of the first sack on end in one corner of the car with the flat side of the sack leaning against the side of the car." He further says: "Make 13 196 HMl VESTING AND MARKETING THE CROP '■m sure that the bottom of the sack is at least G inches from the side of the car. Lean two more sacks against the first. On top of these three sacks place one sack flat, taking care to keep one end at least 10 inches from the side of the car, and the other end well on top of the upright sack nearest the centre line. Another sack should be placed flat on top of this, but with one end tight against the side of the car. The manner in which these two flat sacks are loaded is very important; if they are not correctly and securely placed, the load is practically jV^ ^d|H^H^H||fl certain to shift in transit. The same ^^ ^^I^^^^^^^H ^y^^^^^ <^^' placing the sacks is followed ^HbmB^4^^^^^^H on the opposite side of the car. This ^^^^■^ >^L ^^^^^1 leaves a narrow centre aisle through ^^^HL1|^ ^% ^I^^H ^^^e whole length of the car, insuring ■PJPPWJ^^^^* -ood ventilation (Fig. 105). In the shipment of sacked j)otatoes during cool weather an entirely dif- ferent S3^stem of loading is practised. Bird and Grimes^ suggest laying the sacks lengthwise of the car. The first TOW of sacks is laid about a foot or so from the end of the car; the second icr should extend a little further back ; uiid the succeeding tiers should be piled likewise (Fig. lOfi). The car should be similarly loaded from the other end. The object should be to so load the car as to prevent shifting of the load in transit, and, at the same time, make provisions for a free circulation of air around the load. In severe, cold weather, the area in the centre of the car should be left unfilled, thus permitting the use of a heater stove. The car should not be filled clear to the top. It is desirable to leave at least a foot of space, and in large cars 18 inches is preferable. Hampers do not make satisfactory packages for shipment on account of their frailty. When loaded four tiers high, the lower tier of packages is quite apt to arrive at destination in a badly broken condition. Hampers should be tiered bottom to bottom or top to top as the case may be ; by alternating the order of placement of the first tier, it is possible to effect a considerable economy in space, and at the same time increase the solidity of the load. The Fig. 99. — A splint barrel being covered. Note light construction of barrel. SHIPPING POTATOES 197 railroads dislike to carry hamper shipments of potatoes, because they almost invariably have claims presented for injury sustained during transit. Warm weather shipments should invariably be made in ven- tilated cars (Fig. 105). The ordinary box car should never be used,, unless slat doors are provided. During the cooler autumn weather, the box car is entirely acceptable as long as there is no likelihood of a low drop in tem- perature. As soon as severe, freezing weather may be expected, it is unsafe to use a box car except for very short hauls. When shipments are made to distant i^oints during severely cold weather or, when the car in transit is likely to pass through areas where low temperatures prevail, the ship- ment should be made in refrigerator cars; or in a special t3'pe of car provided with a heater, such as the Eastman heater car which, as far as it is available, is used in the move- ment of potatoes from Maine points. Unfortunately, the supply of refrig- erator and heater cars is utterly inadequate for the movement of the potato crop to market during the winter, making it necessary to use the ordinary box car. In order to use box cars the shipper is obliged to go to the expense of lining them with building paper, and constructing wooden false floors, walls and ends (Fig. 106). Full particulars concerning the conver- sion of a box car into a fairly good substitute for a refrigerator car are given by Bird and Grimes.^ A few favored localities in the South are able to avail them- selves of water transportation in moving their crop to market. The most notable example in this respect is that of the Norfolk, Virginia, district where a large proportion of the New York, Boston, Baltimore, and Wasliington consignments are shipped by boat rather than by rail. (Figs. 107 and 108). The advantage of boat over rail shipment is that the shipper can be absolutely certain The hoop in place ready 198 HARVESTING AND MARKETING THE CROP of the date of arrival of his consignment when he moves it by boat, while by rail he has no assurance when his potatoes will reach market. New York sliipments by boat arrive within 24 hours Fig. 102. — In the Ft. Gibson, Okla., district, potatoes are graded and sackedin the field and are hauled in springless waffons to the shipping station. The grower of this stock marks his sacks with a wheel brand. Courtesy of W. n. Olin. of their departure from Norfolk, and Boston shipments within 36 hours; whereas rail shipments may take several days if not a week or more, de])ending upon freight congestion in terminal yards. Marketing. — The successful marketing of potatoes offers many MARKETING 199 difficulties, particularly in the disposal of the early or truck crop which, on account of its perishable nature and the comparatively short period in which it must be handled, necessitates quick action on the part of the grower or dealer. The development of com- mercial growing centres is, in part, the outcome of a growing recognition of the advantages derived from having a large output to dispose of at a given shipping point. If the crop volume is large enough, it attracts buyers from all the large northern and middle- FlG. 103.— Proper way to load douole-headed barrels to insure an even distribution of weight. _ Loaded in this manner, the bulk of weight on upper layers is supported by heads of barrels in lower tier. Courtesy, Bureau of Markets, U. S. Dept. Agr. western sections of the country, with the result that, when the market demand for new potatoes is brisk, there is keen competition between representatives of different commission firms as to who will secure the largest quantity of the best stock. This competition insures good prices to the grower, and relieves him of the more or less onerous task of attempting to market his own crop. Another advantage is that the crop is given a much wider distribution than it could have possibly received had the growers themselves at- tempted to dispose of it in distant markets. In some sections the growers have their own selling organiza- tion, and in some cases these have been wonderfully successful. One of the largest and most successful of these marketing organiza- 200 HMIVESTING AND MARKETING THE CROP tions is the Eastern Shore of Virginia Produce Exchange located at Onle}', Virginia. The disposal of the new crop becomes difficult and uncertain as to returns when terminal distributing points become glutted through an oversupply and an inactive demand on the part of the retail trade and the consuming public. Under these conditions it often becomes necessary to roll the stock unsold ; the usual practice being to consign it to some commission house. Fre- quently cars are diverted en route, in order to take advan- tage of a stronger market in some other city than the one to which the car was originally billed. In the marketing of the late crop of potatoes the grower or dealer has a longer season of operation, and is not dealing with such a perishal)le product, as the crop is usually mature and the weather cool. The element of risk in shi})ping late potatoes is that of being frosted while en route to destination, or of a portion of the shipment being injured by overheating AvheiJ a stove is used in the car. The method of disposal of the crop is so similar as to require no further discussion. When Should a Grower Sell? — The proper time at which to dispose of his crop is a question wdiich is often difficult for the grower to decide. Each grower should keep himself informed as to the probable extent of the crop, through the monthly reports of the Bureau of Crop Estimates of the United States Department of Agriculture and all other available sources. Whenever it be- comes apparent that a crop in excess of 375 million bushels is going to be harvested, it is a fairly safe assumption that prices will not reach a very high level, unless there is a shortage of other food Fio. 104. — Proper way to load burlap- covered stave barrels. Courtesy of Bureau of Markets, U. S. Dept. Agr. WHEN SHOULD A GROWER SELL 201 crops, such as wheat, corn and other products. When no such shortage exists and a large crop is in sight, it is usually advisable to sell the crop as harvested, provided the price at that time Fig. lOo. — Approved method of loading sacks of potatoes for summer shipment. This insures good ventilation. Courtesy of the Bureau of Markets, U. S. Dept. Agr. affords a reasonable return on the investment involved in its pro- duction. There are seasons when it may be advisable to sell the crop from the field at a price which barely covers the actual cost Fig. 106. — Approved method of loadins sacked potatoes for winter shipment. Note false floor and ends. This method of loading insures an even and uninterrupted circulation of air. Courtesy of the Bureau of Markets, U. S. Dept. Agr. of production, and thereby avoid the extra cost of storing and re- handling the crop later in the season, with a fair prospect of not receiving any more for it at that time than when harvested. It 202 HARVESTING AND MARKETING THE CROP is, of course, apparent that if everyone followed this advice it would result in a complete slump in prices. In fact, it would be a physical impossibility for the railroads to move the entire late crop of po- tatoes during the harvest period; and even if this were possible, there is enough storage to take care of only about one-third of the crop. It thus becomes evident that at least two-thirds of the late crop must he stored on the farm, to await distribution throughout the late fall, winter and early spring months. :,k3«5^-v/>'- Fig. 107.— Hauling the crop to shipping the Norfolk district. On the other hand, when a short crop is apparent it would not be a good plan for every grower to hold on to his whole crop in the expectation of receiving a high price in the spring. The result would be that prices throughout the early part of the winter season would be forced to such an extremely high figure that the con- sumption of potatoes would be very materially curtailed, with the probability that, Avhen the grower got ready to dispose of his crop, he would find the market overstocked, and the consuming public's taste diverted to other starchy food substitutes. Under such con- ditions, the price received for the crop might be very much below what it should be as judged by the season's supply. Good stable WHEN SHOULD A GROWER SELL 203 prices and market conditions can only be expected when there is a steady flow of potatoes to the distributing centres, thus preventing wide price fluctuations, and insuring a maximum consumption. Every commercial late croj) potato grower should aim to provide sufficient storage space on his own farm to enable him to store his Avhole crop, if need be. When provided with the necessary facili- ties for taking care of his crop, he is not o])liged to dispose of Fig. 108. — Boats from truck farms awaiting their turn to unload at the Old Dominion docks, Norfolk, Va. An ideal method of conveying the crop to shipping point. it at harvesting time if the prices being paid are ruinously low. On the other hand, if a satisfactory price is being offered, it is often justifiable to dispose of the whole crop, even though ample provision for storage is at hand. The ideal method of marketing the crop would be for each grower to dispose of a sufficient portion of his crop to take care of the needs of the trade. It goes without saying, of course, that such an ideal will never be reached, as there Avill always be those who, through lack of storage facilities, are obliged to sell their crop as harvested. 204 HARVESTING AND MARKETING THE CROP Stabilization of prices for farm products, and potatoes in })ar- ticular, can only be accomplished through an effective and compre- hensive growers' organization for the purpose of pooling crops and selling them through some central selling agency. Whether such a millenium in the marketing of potatoes will ever be reached is difficult to say. The present trend of thought and action is in that direction. This is evidenced by the recent formation of a number of strong farmers' cooperative organizations. QUESTIONS ON THE TEXT 1. What are tlie chief factors involved in harvesting the potato crop? 2. What fixed period in the growth of the crop do the data of har- vesting represent? 3. What determines the date of havesting? 4. How do the southern and nortliern dates differ? f). What two general classes of harvesting implements are used? G. Name the hand implements that may be used. 7. Name and describe the non-elevator types of diggers. 8. How is tlie ordinary plow used ? 9. How do potato diggers 2 and 3 operate? 10. How docs class 4 implement differ from 2 and 3 in its operation? 11. What can you say of the number of types of elevator potato diggers? 12. What are some "of the outstanding features of difference in their construction ? 13. Why are four horses necessary to operate them in some sections and not in others? 14. Describe the gasoline equipped digger. What is the function of the gasoline engine in the operation of the digger? 15. How may the cutting and bruising of the tubers by diggers be minimized ? If). How does fast driving increase the amount of tuber injury? 17. How important is it to lower the rear rack or conveyor belt? Why? 18. How do practices differ in different sections of the country with respect to picking and handling the tubers? 19. Describe the IMaine method of picking and handling the crop. 20. Describe the New Jersey method of picking and handling the crop. 21. HoAV does western New York handle the crop? 22. In the West and in some sections of the South how is the crop usually gathered ? 23. What is the practice in the tule lands of the Stockton, California, district? 24. What is the cost of picking potatoes? 25. What impetus did potato grading receive during the war? 26. What can you say of its probable permanency? 27. Describe the grades advocated by the U. S. Department of Agriculture. 28. (^f what importance is it to the grower to have his potatoes properly graded ? QUESTIONS ON THE TEXT 205 29. Dcbcribe the operation of the belt conveyor type of sizer. 30. Describe the operation of the western type of sizer. 31. Describe the hand screen or sizer and tell how it is operated. 32. What do the Maine growers use as an aid in the operation of grading potatoes? Is it in any sense a sizer? 33. Discuss grading for a fancy trade. 34. What are the sizes of tubers suggested? 35. What are some of the advantages of having potatoes separated into uniform sizes? 36. Of what advantage would it be to the retailer to handle potatoes in small packages? 37. Of v/hat advantage to the consumer from the quality standpoint? 38. Is the average grower ordinarily able to successfully market his crop? Give reasons. 30. What kinds of containers are used in shipping the crop to market? 40. Describe and explain the respective merits of each container and reasons for its use. 41. What are the chief oljjections to large sacks? 42. What trouble is caused from the use of sacks of varying capacities? 43. What objection is there to the use of the hamper? Where used? 44. How should double-headed stave barrels be loaded in a car?' 45. Should burlap-covered barrels be loaded in the same manner as the double-headed barrels? Why? 46. How should summer shipments in sacks be loaded? What type of car? 47. How does autumn or winter loading of cars differ from summer loading? 48. How may box cars be made suitable for use in cold weather? 49. What are some of the difficulties involved in the marketing of the early or truck crop? 50. How has the development of large commercial production centres in- fluenced the marketing problem? 51. Why is the marketing of the late crop of potatoes a less difficult problem ? 52. How is the grower to determine when it is the proper time to sell? 53. To what extent is the railroad a limiting factor? 54. Why should the commercial grower make provision for the storage of his crop? 55. What would be the ideal method of marketing the crop? 56. How may the price of potatoes be stabilized? 57. What is the present trend of thought in this direction? QUESTIONS SUGGESTED BY THE TEXT 1. At what stage of growth do the local growers harvest their potatoes? 2. List the methods of harvesting used locally, in order of popularity. 3. Which methods are least injurious to the tubers? 4. Describe local methods of picking and handling potatoes. 5. From local growers ascertain the cost of picking potatoes. 6. What grading and sizing is done locally? Give methods. 7. Describe local methods of shipping and marketing. 8. What containers are used? 206 ■ HARVESTING AND MARKETING THE CROP References Cited 1. Bird, H. S., and A. M. Grimes. 1918. Lining and loading cars of pota- toes for protection from cold. U. 8. Dept. Agr. Bur. Mkts. Doc. 17: 1-26. Oct., 1918. 2. Grimes, A. M. 1919. Handling and loading southern new potatoes. U. 8. Dept. Agr. Farmers' Bui. 1050: 1-18, May, 1919. 3. Moke, C. T., and C. R. Borland. 1910. Commercial handling, grading and marketing of potatoes. U. S. Dept. Agr. Farmers' Bui. 753: 1-40, Nov. 1, 1916. 4. Tbuax, H. E. 1920. United States grades for potatoes. U. S. Dept. Agr. Bur. Mkts. Circ. 96: 1-4, May, 1920. CHAPTER XIII POTATO STORAGE AND STORAGE SHRINKAGE As the agricultural and economic importance of perishable food products increases in any given community, state or country, the question of storage at once enters into the problem of their conservation and distribution throughout the period in which these crops are not normally produced. The relative ease with which the potato can be held in storage during the winter months in the northern section of the United States and Canada, or, under similar climatic conditions, in other ])ortions of the world, has not served to stimulate any very careful study looking toward the determination of the optimum storage conditions for this crop. In view of the fact that the quantity of potatoes annually stored for winter and spring use is relatively large, it would seem that we should know more than we now do about the actual shrinkage that is likely to occur under certain conditions during a given storage period. Object of Storage. — The primary object in the storage of any product is that of prolonging its edible stage of maturity throughout a longer period of time. The secondary, though by no means unimportant, object of storage is that of minimizing the losses occurring during the storage period. The chief sources of shrinkage in storage result from moisture losses and decay Storage makes it possible to hold over the late or main crop of potatoes in the North throughout the winter and spring months, thereby enabling the grower or the dealer to dispose of the crop at such times as the requirements of the market demand, and by so doing avoid marketing it when there is an over-supply and con- sequently low prices. The successful storage of potatoes is dependent upon a number of factors among which may be mentioned temperature, humidity, aeration, exclusion of light, soundness of tubers stored, freedom from dirt and moisture, and, last but not least, size of the pile. Storage Temperature. — There are many current notions re- garding the best temperature at which to store potatoes, but until quite recently there have been few experimental data upon which 207 208 POTATO STORAGE AND SHRINKAGE to base conclusions. This has boon particuhirly true witli respect to seed stock. The following opinions are given with a view of ])resenting such information as we have- at the present time. Cooper^ recommends a temperature of from 33 to 35 degrees F. as about right for potatoes. Fraser," in discussing ventilation and temperature, says "The potato must be kept cool, al)out 33 degrees l^eing a favorable temperature." Corbett* recommends a temperature of 34 degrees as a minimum and 45 degrees as a maximum throughout tiie entire storage period. Grubb and Gilford" believe that in winter the temperature of the potato storage house should be kept as near 32 degrees as possible. In this connection they say, "It is best when it does not go below 30 degrees nor above 36 degrees." Wright and Castle, '^^ in their discussion of storage, mention the investigations of Dr. Parisot, a French scientist who, as a result of his studies, recommended 46 degrees as the ideal storage tem- perature for potatoes in winter. Appleman^ found in some recent investigations that ordinarily the freezing temperature of the pota- to lies between 28 and 26 degrees. Some years ago the writer, while conducting potato investigations at the Vermont Station, used a basement cellar for storage purposes in which the tempera- ture on a number of occasions dropped to 30 degrees and on one occasion went as low as 28 degrees. Aside from a rather tardy germination of the seed when planted, no ill effects were noted from these low temperatures. Since 1911, a considerable portion of the seed potatoes produced by the Office of Horticultural and Pomo- logical Investigations of the United States Department of Agricul- ture have been stored in an artificially refrigerated room in which the temperature could be varied as desired. It has beer, the custom in storing potatoes in this room in the fall to reduce the temperature as rapidly as possible until it reached 40 degrees after which it was held at that point until about February 1, when the temperature was gradually lowered until it reached about 35 degrees. I^sually the temperature was allowed to fluctuate between 37 and 35 degrees. This practice has served to hold the tubers in perfect condition so far as firmness and dormancy are concerned. Eemembering that the sole function of storage is to preserve the stored product in as nearly its original condition as possible, it would seem that the maximum temperature at which the tubers can be held and still remain firm and dormant should be regarded as the most desirable one to use. EFFECTS OF LOW TEMPERATURE 209 Butler's studies- led liim to coiidude that a temperature of 3.74 degrees C. or approximately 39 degrees F. was sufficiently low to retard germination indefinitely. He also found that germi- nation could be more completely arrested, in air nearly devoid of oxygen (dead air) at a temperature of 9.31 degrees C. (practically 44 F.) than in free air at 3.74 degrees C. In a later publication Butler-* says, *'The temperature of storage for domestic use should be 46 degrees F. or as near this temperature as is consistent with proper keeping. At lower temperature than 46 degrees F. potatoes become more or less sweet and watery, conditions that are, culinarily, very undesirable. Storage in dead air is open to the same objection as storage at low temperature." Recent studies, undertaken by the writer in the fall of 1918, and continued throughout the whole of 1919, have demonstrated that tlie germination of potatoes can be arrested when stored at a tem- perature of 40 degrees F. Conclusion. — A temperature of about 36 degrees is sufficiently low for all practical purposes, and in the earlier stages of the storage period a temperature of 40 to 43 degrees is probably just as efficient as a lower one. When potatoes are first stored every effort should be made to reduce the temperature as quickly as possible. This is particularly desirable if the Aveather is warm when they are dug, as they absorb heat readily and also develop heat rapidly when stored in bulk under the conditions mentioned. In natural storage this is most easily accomplished by a little attention to the opening of doors and ventilators in the evening, when the nights are cool, and closing them early in the morning. Chemical Effects of Low Temperature on the Tuber. — It has long been recognized that when potatoes are subjected to temperature in the vicinity of the freezing point of water, 32 degrees F. for any considerable period there is an appreciable accumulation of sugar in the tuber which, when cooked, imparts or a more or less sweetish taste to the flesh. This condition of the tuber may or may not be objectionable, according to whether it is or is not intended for immediate table use or removal from storage. In some recent studies by Appleman (I.e. p. 330) it was found that the exposure of these tubers for a week to a temperature of from 70 to 75 degrees was sufficient to transform four-fifths of the sugar accumu- lation into starch. These results would indicate that a sugar accumulation in potato tubers is not such a serious matter, unless 210 POTATO STORAGE AND SHRINKAGE they are desired for immediate use. The phenomenon of sugar accumulation in the potato is an interesting one, because it is a direct result of throwing the life processes, continually going on within the tuber, out of equilibrium through a lowering of the temperature. Appleman says {I.e. p. 330), "At 46 to 50 degrees F., the process of respiration and synthesis (in the potato) of starch from sugar consumes all the sugar that is formed by the action of the diastase ; therefore no sugar accumulates. Below this temperature, the two former processes are inhibited to a much greater extent than the latter; consequently sugar begins to accu- mulate. At 32 degrees F. respiration and starch synthesis are so slight that a large percentage of the sugar formed accumulates; the sup})ly is greater than the consumption." Humidity. — Very little information regarding the proper de- gree of humidity to maintain in the storage house or room is available. The question as to whether the humidity content of the air should be high or low is one to which the data at hand do not permit a satisfactory answer. In all of the storage work with which the writer has been associated, an attempt has been made to maintain sufficient moisture in the air to keep the tubers jfirm, and at the same time not have it so saturated as to produce a film of moisture over the surface of the tuber. Cooper {I.e. p. 503) suggests a humidity of from 85 to 90 per cent as about correct for a potato storage room when the temperature ranges from 33 to 35 degrees F. This suggestion coincides with our own observa- tions as, under the conditions which have been mentioned, it has been found that the humidity content of the air was approximately 85 per cent. It would, therefore, seem that until further light has been thrown upon this subject as a result of careful experi- mental studies, it is safe to advise an air saturation of about 85 per cent. One can, of course, conceive of a condition where it might be unwise to keep the air as moist as this. For example, where storage decays were present a drier atmosphere would tend to check the shrinkage from disease to a greater extent than that resulting from increased transpiration due to a drier air. Aeration. — The importance of a good supply of pure air in the potato storage house has not, so far as Ave know, been demon- strated by any carefully conducted experiments. It seems reason- able, however, to assume that it can hardly be other than desirable from the health standpoint of the tuber. In order to insure an AERATION 211 ample supply of pure air in the storage house or room, generous provision should he made for ventilation. Ventilators or air flues should be so provided as to insure a rapid and even distribution of air throughout the structure. The European grower finds it advantageous to store seed potatoes in open crates or shallow trays which are stacked up in tiers, thereby insuring a free circulation Fig. 109. — Seed potatoes stored in shallow trays or flats. of air around the tubers (Fig. 109). Specially constructed bins may partially serve the same purpose. (See Chapter XIV on storage house construction.) In potato storage house construction every effort should be made to exclude the light. Potatoes intended for table purposes should not be exposed to light any more than is absolutely necessary in the harvesting and storing of them. The quality of the potato is very quickly injured by light. An exposure of two or three days to strong light (not sunlight), very materially affects the eating quality of the potato, and a long exposure to even a very weak light is also injurious. The storage house or room should be kept as dark as possible, if the quality of the potato is to remain unimpaired. 14 212 POTATO STORAGE AND SHHINKAGE Potatoes intended for seed purposes arc not injured by light, in fact many of the best European growers purposely expose their seed stock to the light under the firm conviction that it starts them into growth quicker and makes more vigorous plants. On the subject of aeration Butler-^ says, "Aeration should' be sparingly given and the air should flow in at the bottom of the bins, not from the top. Cold air holds less water than warm air, and cooling the top of a bin results in a deposition of moisture, or the maintenance of too high an atmospheric humidity." This statement is somewhat at variance with accepted notions concern- ing aeration, though more or less in keeping with present practices, so far as moderation in the amount of air admitted into most commercial or farm storage houses. The admission of fresh air through the floor of the cellar is i]i line with what is already em- bodied in the United States Department's storage house on Aroos- took Farm, Presque Isle, Maine. Fresh air is brought into this house through an 18-inch concrete conduit which discharges its flow of air through an opening in the center of the driveway. The Avarm air is removed from this house by means of two large ventilators connecting with roof cupolas (Fig. 133). Soundness of Tubers Stored. — One of the most prolific sources of loss in storage is that resulting from the storing of unsound tubers. Unsound tubers may be classified under two heads: (a) Those that are mechanically injured such as bruised or cut tubers ; (b) those that are infected with disease, such as the late blight rot and the powdery dry rot. The losses resulting from mechan- ically injured tubers are very largely dependent upon storage house conditions ; for example, if the temperature and humidity are high, the shrinkage will be much greater than if the temperature and humidity are approximately right. Much also depends upon the sanitary condition of the storage room. If the storage house has been carefully disinfected before placing the potatoes in it, the chances for infection of the cut or bruised surfaces are largely eliminated. If, however, unsanitary conditions prevail, the presence of cut and bruised surfaces ofi'er an easy point of infection for a number of storage decay organisms. The more carefully, therefore, that po- tatoes are harvested and stored, the better will be their keeping qualities and the less the shrinkage. Every effort should be made to remove all diseased tubers from those intended for storage purposes. Ordinarily, the late blight rot is the most serious storage trouble in the northeastern part of SIZE OF STORAGE PILE OR BIN 213 North America, while the powdery dry rot is probably the worst in the western states. In regions where late blight is likely to be prevalent, it should be so controlled by the thorough spraying of the growing plants as to effectually prevent tuber infection. In any case, however, every effort should be made to remove disease- infected tubers before placing them in storage. Freedom from Soil and Moisture. — While it is recognized that it is not always possible to harvest the potato crop in such condition as to insure freedom from any unusual amount of soil, it is believed that, insofar as it is consistent with the safety of the crop, harvesting operations should be so timed as to insure a mini- mum amount of soil adhering to the tubers. It is not a good practice, if obliged to harvest the crop when the soil is too wet for good results, to gather the tubers as soon as dug. Advantage should be taken of every opportunity to leave them exposed to the sun and wind for an hour or more, in order to allow the excess moisture to dry off and to get rid of as much excess dirt as pos- sible. When potatoes are stored with large quantities of moist soil adhering to the tubers, they are almost certain to develop a considerable amount of heat, especially if stored in bulk. Piles of potatoes stored in this condition may cause as large a volume of steam to escape as might ordinarily be expected from a pile of fermenting manure. It requires very little imagination on the part of any thinking person to figure out that potatoes stored under such conditions are much more likely to decay; and even if no decay does occur, to realize that when the tubers are subjected to such high temperatures, the transpiration losses are very greatly in- creased. Let us not forget, therefore, that dirt and moisture are undesirable factors in potato storage, and make every effort to store clean and dry tubers. Size of Storage Pile or Bin. — It is a bad practice to store potatoes in large piles or bins without some provision being made to ventilate the pile. In many instances, potatoes are piled to a depth of from 10 to 15 feet and correspondingly large in the other two dimensions. If the tubers are reasonably dry, free from dirt and well ripened, no serious harm may result from storing in such large piles. Under such conditions, whatever injury they may sustain will be incurred in putting them in the storage house or bin, and the crushing or cracking of those at the bottom of the pile by the excessive weight of those above. On the other hand, if the crop is harvested when the ground is wet, and goes into storage 214 POTATO STORAGE AND SHRINKAGE under the conditions mentioned in the preceding paragraph, it is dangerous to store to a greater depth than six feet; if the bin or storage space is a large one, ventilator shafts should be inserted in it at intervals of six to eight feet apart. These shafts are easily constructed and may be of any diameter desired. They may be either square or rectangular in shape. If square, a dimension of 18 by 18 inches, or 2-4 by 24 inches will be found convenient. A simple form of construction consists in the use of 2 by 4 uprights as corner supports, upon which are nailed four or five-inch strips of inch lumber, so spaced as to give one to one and a half inch openings be- tween each strip. These air shafts may be made any height desired, and should be placed in position as the bin is filled. Another method is to use ventilated division walls, so constructed as to leave an air space in the centre of the wall, see figure 109 in chapter on storage house construction. Storage Shrinkage. — The shrinkage involved in the storage of potatoes from Autumn until late Spring may vary from less than 4 to over 20 per cent by weight, depending upon the type of storage house used, the care given to maintaining the proper temperature and humidity, and the condition of the tubers when placed in storage. The natural and inevitable losses in storage are those in- volved in the transpiration and respiration processes continually going on in all living matter. Shrinkage Due to Transpiration and Respiration. — Com- paratively little attention has been paid to the moisture shrinkage of potatoes in storage, by the potato growers of the United States, and, with but one or two exceptions, such data as have been pub- lished are not of scientific value, as they do not represent carefully observed temperature and humidity conditions in the storage room. An examination of the literature on the subject disclosed the fact that French and German investigators have made a more or less careful study of the question and, in some respects, have secured very interesting data. For the most part, however, their observa- tions were made on tubers stored at a much higher temperature than growers in this country would consider suitable for the potato. The temperatures at which most of their experimental work was con- ducted varied from 43 to 52 degrees F., and, in some instances (Nobbe's), much higher than this. Foreign and American Investigations. — In 1865, Xobbe^ re- ported the results of his experimental studies concerning the loss of water and carbonic acid gas from potato tubers in storage. His FOREIGN AND AMERICAN INVESTIGATIONS 215 studies covered the period between December 13 and June 7. Unfortunately, Nobbe's observations were based on but two selected tubers in each lot studied, a quantity much too small for experi- mental purposes. It is thought desirable, however, to present it, in order to show the character of the data taken. Nobb'e so ar- ranged his experiment that it involved eight separate conditions, or factors. Each of the eight lots of tubers was subjected to the following factors: Decrease in Weight 1. Cool-dry-light (50 to 61 F.) 34.05 grms. 2. Warm-dry-light (77 to 05 F.) 57.25 grma. 3. Cool-moist-light 20.15 grms. 4. Warm-moist-light 57.65 grms. 5. Cool-dry-dark 34.45 grms. 6. Warm-dry-dark 63.25 grms. 7. Cool-moist-dark 13.35 grms. 8. Warm-moist-dark 62.10 grms. Inasmuch as Nobbe fails to state the original weight of each lot of tubers, the data given lose much of their significance, as it is impossible to compute the actual percentage loss. The signif- icant factor determining loss is temperature. Light influence in this experiment appears to be a negligible one. In the case of dry versus moist-.storage air conditions, an appreciable decrease in Aveight is noted for those stored in dry chambers. An interest- ing feature in Nobbe's paper is that pertaining to his determination of the relative proportion of moisture and carbonic acid gas loss in storage. According to his figures, the ratio of gas to water is 1 to 3.5. Mertzel and Lengerke's Agricultural Calendar for 1891, p. 151, contains data regarding the decrease in weight of 100 kilos of potato tubers in storage, but does not vouchsafe any information regarding the source of the data. The observations, as reported, extend from the end of October to the end of May. The per- centages of loss in weight are presented by months. November 56 per cent. December 2.58 per cent. January 1.00 per cent. February 1.40 per cent. March 1.06 per cent. April 1.40 per cent. May 2.00 per cent. Total loss 10.00 per cent. 216 POTATO STORAGE AND SHRINKAGE In 1891, Wollny,^"' after reviewing Nobbe's investigations at some length, presents the results of his own studies on the moisture loss sustained in storage of a dozen varieties of potatoes. His observations were made on 100 earefull}^ selected tubers of each variety during the period from Octol)er 5 to May 1. Each lot was weighed at the beginning of the experiment, after which the pota- toes were placed in tin containers and stored in a dry, deep cellar, in Avhich the proper light, and a rather constant temperature (from 43 to 52 degrees F.), were maintained. The subsequent weighings were made on the first and fifteenth of each month. The total loss in weight for each variety during tlie whole period was as follows : Blue Princess 4.55 per coiit. Six Weeks 4.87 jjer cent. Late Rose 5.27 per cent. Gold Else 5.48 per cent. Sovereign 5.71- per cent. Early Rose 6.07 per cent. Marmont 6. 40 per cent. Achilles (5.49 per cent. Snowflake 0.65 per cent. Lubenauer 6.78 per cent. White Rose 7.28 per cent. King of the Earlies 8.48 per cent. Average loss 6.17 per cent. Wollny's conclusions were that the reduction in weight of potatoes in storage iu a cool, dry, and moderately light place, is greatest immediately after harvest, diminishing continually from that time until March, but increasing from then on. He concluded also that the apparent differences in percentage loss between the different varieties of potatoes during storage do not stand in any conformable relation to the size of the tuber, nor to the length of the vegetative period of the variety. Denaiffe/' in 1907, reports a somewhat similar investigation to Wollny's. His studies included eight varieties, on which he observed the decrease in weight of tubers for a })eriod of about 14 months. The quantity of each variety used was 100 kilograms, on which readings were taken each montli. In discussing his data, Denaiffe states that the loss in weight during storage varies with tlie varieties, and is not tlie same for all months. TAFT AND HEDRICK 217 The losses sustained by each variety from December 1, 1904, to June 1, 1905, were as follows: Up-to-date 5.0 per cent. Imperator 5.15 per cent. Professor ]\l;ierfker 6.55 per cent. Quarantaiiie de la Ilalle 6.60 per cent. Parisienne 7.10 per cent. Belle de Fontonay ^ 7.30 per cent. Saucissc rouqe . . 9.35 per cent. Royal kidney 9.50 per cent. Average loss 7.00 per cent. This observation is condrniatory of tliat of Wolhiy, and simply emphasizes the fact that all varieties do not give similar responses in storage. The maturity of the variety, the character of the skin, and its period of winter rest are factors which influence the activity of the transpiration and respiratory processes of the tuber. A comparison of these losses by months, as noted by Wollny and Denaiffe, indicates somewhat wide variations in the percentages of loss in weight under (lifFeroiit environmental conditions and with different varieties. Comparison of Wollny's and Denaiffe's data, giving per- centage of loss by months: Date Wollny, (12 var.) Denaiffe (.S var.) Oct. 5 to Nov. 1 2.02 per cent Xovenilier 1.18 per cent ■ December 0.75 per cent 1.125 per cent. January 0.50 per cent 1.193 per cent, February 0.81 per cent 0.725 per cent. March 0.41 per cent 1.218 per cent. April 0.50 per cent 1.0 per cent. May 1.743 per cent. Given similar conditions and varieties, well-ripened tubers shoidd not show any appreciable loss in weight during the first few mouths of storage, jirovided a uniform and moderately low temperature is maintained. For present uses, Wollny's data are more valuable, in that they account for the loss in weight from October 5, as against Decem- her 1 in Denaiffe's studies. Taft and Hedrick " report a loss in weight on a barrel of pota- toes, stored in a basement cellar from September 30 to March 218 POTATO STORAGE AND SHRINKAGE 28, of 5 per cent, and G.5 per cent from March 28 to May 1 — or a total loss of 11.5 per cent. It is self-evident that the heavy loss incurred during the latter period must have been the result of high temperature and possibly of germination. Fraser," (p. 151), reports a loss of 12 per cent in Sir Walter Raleigh stored in crates in a cool cellar from November 6, 1903, to April 27, 1904, Avhile under similar conditions. Carman No. 3 showed a decrease in weight of nearly 10 per cent. Butler's studies,-'' (p. 4), on the relation of temperature to loss in weight of Green Mountain potatoes placed in storage November 12, shows the following percentage losses for 30, 60, 90, 120, 150, 180 and 210 day periods at three temperatures. of Temperature on Respiration and Transpiration Losses from Potatoes. Per cent of loss in weight after Mean temperature of storage 30 days 60 days 90 days 120 days 150 days ISO days 210 days 39 degrees F. 48 degrees F. 60 degrees F. 0.58 1.26 1..52 1.43 2.53 2.77 1.43 3.37 4.01 2.29 4.21 G.65 2.58 7.18 11.56 2.15 2.44 A comparison was also made of the respiration and transpi- ration losses from two lots of Greeu Mountain potatoes removed from ordinary storage on January 26 and subjected to a tempera- ture of 50 degrees F., one lot being exposed to a free circulation of air, while the other was stored in dead air. The percentage loss at the end of 90 days was 8.96 from those in free air and 1.35 from those in dead air. At the end of 119 days, these per- centages had increased to 17.24 and 2.79 respectively. Those exposed to free air began to germinate in 43 days, while those in dead air remained dormant. Numerous inquiries by the writer regarding potato storage losses have invariably elicited from the grower or shipper the reply that no definite effort has been made to determine the losses, either collectively or separately. It is the general impression that the losses from moisture and decay vary from 10 to 20 per cent. Under exceptionally good storage conditions, transpiration and respiration losses of less than 4 per cent have been reported. Such losses do not, of course, take into consideration those involved in the ger- mination of the tubers. In the process of germination both the QUESTIONS ON THE TEXT 219 respiration and transpiration processes are quickened, because the temperature of the room must be relatively high to permit of germi- nation; and, in addition to this, the starch content of the tuber is very rapidly transformed into sugar. Under these conditions, the shrinkage is heavy and the quality of the flesh rapidly deteriorates. QUESTIONS ON THE TEXT 1. What is the primary object of storage? Secondary object? 2. What are the chief ' sources of loss during the storage period? .3. In what sections of the country is potato storage of the greatest importance? Give reasons. 4. Upon what factors is successful storage dependent? 5. Upon what are based the data regarding the proper storage tf^mperature for potatoes? 6. What does Dr. Parisot regard as the ideal temperature? 7. What is the freezing temperature of the potato as determined by Dr. Appleman? 8. What temperatures were found satisfactory by the Office of Horticul- tural and Pomological Investigations during the past several years ? 9. On first storing potatoes, what attention should be given to the manipu- lation of the storage house? 10. What is the chemical effect of prolonged low temperatiire on the po- tato tuber? How serious is this? 11. How may such an effect be dissipated? 12. What information have we on the subject of humidity in the storage house ? 13. Of what importance is the question of aeration on potato storage? 14. What are Butler's suggestions regarding aeration? How much are his ideas at variance with current notions? 15. Why should there be an effort made to exclude light from the storage house ? 16. What is one of the most prolific sources of loss in the storage house? 17. Under what two heads may unsound tubers be classed? 18. What precautions shoxild be observed relative to the exclusion of diseased or injured tubers? 19. Why have the tvibers free from an excess of soil or of moisture before storing them ? How ? 20. What fjactors limit the size of the storage pile or bin? 21. What should be the limiting factors governing the size of the pile or bin? 22. What percentage of shrinkage is usually entailed in storage? 23. What information have we upon the actual natural losses in storage? 24. What results did Nobbe secure from his storage studies? 25. What losses are shown in the data published in Mertzel's and Lengerke's Agricultural Calendar for 1891? 26. In Wollny's investigation of the moisture loss sustained in storage, what evidence is seen that he took proper precautions to secure desirable material for study? 27. What is there to show that the temperature at which the tubers were stored was sufficiently low to determine the minimum loss from transpiration and respiration? 220 POTATO STORAGE AND SHRINKAGE 2S. Can you explain why the results secured show such variations in the percentajie of loss of the 12 varieties studied? 2!(. What were Wollny's conclusions regardinj^ the losses? 30. What was the nature of Uenaiffe's investigations? 31. Compare the results secured by DenaiiTe with those of Wollny? 32. From a scientific as well as a practical standpoint, wiiich c"f the two sets of data has the greatest value? Give reasons. 33. What loss in weight did Taft and Hedrick observe in their experiment? 34. What loss did Fraser note in his studies? 35. What losses did Bixtler note in his investigations? 36. What is the general impression by growers and doalers regarding the percentage of storage loss? 37. Under good storage conditions and with sound stock, how low may the percentage of loss be? QUESTIONS SUGGESTED BY THE TEXT 1. Do local growers or dealers store potatoes? 2. Ascertain the various lengths of storage periods. 3. What examples can you find of serious rotting and heating? 4. Obtain examples in homes or boarding places of potatoes that have become sweet or watery from storage. 5. Trace such example and determine, if possible, how and where sloi-od, and temperature of same. References Cited 1. Applemax, C. O. 1912. Changes in Irish potatoes during storage. Md. Sta. Bui. 167: 330, May, 1912. 2. BiTTLER, O. 1910. The effect of the environment on the loss of weight and germination of seed potatoes during storage. Jour. Am. »S'oc. Agron. 11: 114-118, March, 1919. 2a. 1919. Storage of potatoes. N. n. f^ta. Circ. 20: 7, June, 1919. 3. CooPEK, M. 1914. Practical Cold Storage, 2nd. ed. 1914: 503. 4. CoREETT, L. C. 1913. Garden Farming. 1913:369. 5. Dexaiffe, H. 1907. Experiences sur la conservation des pommes de terre et leur perte de poids. (Experiments in the conservation of potatoes and their loss in weight). Le Jardin 21: 76-79, illus. 1907. 6. Frasek, S. 1905. The Potato. 1905: 150. 7. Grubb, E. H., and W. S. Guilford. 1912. The Potato. 1912-132. 8. NoBBE, F. 1865. Ueber die zu und abnahmen des starkegehalts der kartoffelknolle. Landioirthsch, Versuchsta. 7: 451-463, 1865. 9. Taft, L. R., and U. P. Hedrick. 1895. Potatoes. 3Iich. Sta. Bui. 119: 1-16, Feb., 1895. 10. Wollny, E. 1891. Untersuchungen iiber den gewichtsverlust und einige morphologische veriinderungen der kartoffelknollen bei der auflochwahrung im keller. Agr. Physik. 14: 286-302, 1899 (see p. 291). 11. Wright, W. P., and E. J. Castle. 1906. Pictorial Practical Potato Growing. 1906: 97. CHAPTER XTV TYPES OF STORAGE HOUSES, THEIR CONSTRUCTION AND COST In the present discussion of types of storage, either in especially constructed storage houses or otherwise, it is our purpose to briefly trace its development from the primitive to the modern up-to-date artificially refrigerated structure. Storage in its primitive state consisted in burying the product in the soil, or storing it in a cave or excavated chamber of some sort. As agriculture developed, and became more specialized, and wealth increased, better and more expensive types of storage w^ere demanded, in order to meet tlie growing necessities of large urban populations. In the case of the potato, one of the simplest and most primitive forms of storage, commonly known as pitting, is still practised to a limited extent in some sections of the country. The types of storage to which consideration is given in the ensuing portion of this chapter embrace everything that may justly be regarded as applicable to the potato. The house cellar is omitted, because it is assumed that it does not require discussion or explanation, other than to say that in special late potato-producing sections it is not generally employed for storage purposes. The following types are believed to represent those that are now gener- ally employed for potato-storage purposes : 1. Pitting. 2. The dugout, or cellar type of storage house. 3. The insiilated wooden structure. 4. The Aroostook, Maine, type. .'). The artificially refrigerated structure. Pitting. — Potatoes may be successfully stored in pits if good drainage is provided and sufficient covering applied to thoroughly insulate the stored tubers from external heat and cold. Strictly speaking, the term pitting is somewhat misleading; it does not necessarily imply an actual pit in the ground, as will be noted in the discussion that follows. In pitting potatoes, good drainage is the first consideration in selecting the site. The land must either be well drained naturally. 221 222 TYPES OF STORAGE HOUSES or else so situated as to make good drainage possible. Little, if any, excavation is ordinarily made in pitting potatoes, aside from making a smooth surface on which to pile the tubers. Fig. 110. — First steps in pitting potatoes. Shape of Pile. — The shape of the pit should l)e that of a paral- lelogram, rather than square or circular. The customary practice is to pile the tubers in a ridge or inverted A -shaped fashion as Fig 111. — Exterior view of a large potato storage cellar in process of construction on the Sweet ranch, Carbondale, Colorado, showing construction of vestibule entrance and the covering of roof with straw. shown in (Fig. 110). When piled in this way, it exposes a greater area of the pile to the air and, when covered, sheds rain much better. Its size is, of course, determined by the quantity of potatoes to be stored, and the limit of safety as regards danger from loss if PROVISION FOR VENTILATION 223 stored in too large a pile; because, as the size of the pile increases, the difficulty of cooling it quickly is enhanced ; and, should decay in the tubers become active, greater losses are sustained in large than in small i)iles. Generally speaking, the limit of size should be from 300 to 350 bushels or half a carload. porting : ■w of same cellar showing roof construction and method of sup- ly through the storage cellar. Messrs. Lou D. Sweet on the leit and F. E. Sweet on the right. Provision for Ventilation. — When pitting the tubers, some provision should be made for ventilation. A common practice abroad is to take a handful of rye or wheat straw and stand it in a vertical position on top of the pile while the straw and earth covering is being applied, after which it is pulled out, thus providing a vent for the escape of heat and moisture. Probably a better practice is to construct a small ventilator shaft of six or eight inches diameter out of inch lumber. Bore numerous holes an inch or so in diameter in the lower portion of the shaft, and insert it 224 TYPES OF STORAGE HOUSES in the centre of the pile as tlie tubers arc bein^^ ])itte(L Tlie nearer it extends to the bottom of the pile, the more perfect the ventilation provided. It should extend three or four feet above the tubers, so that when the covering is applied it will protrude 18 to 24 inches above it. The ventilator should be provided with a cap to prevent the entrance of snow or rain. In severe weather it should be stopped with straw. If the pile is more than ten feet in length, a second ventilator should be inserted. A good rule to follow is to have a ventilator every eight feet. This insures reasonably good ventilation of all uortions of the pile. -aftS» Fig. 113. — Completed structure showing cribbed vestibule on the Sweet ranch, Carbondale, Col. Protection Against Frost. — As soon as the potatoes are in position, they should be immediately covered with a sufficient quan^ tity of straw or marsh hay to exclude light. The pitted tubers should be left in this condition as long as they are safe from frost. This gives them a chance to go through the sweating process and get thoroughly cooled off, after which there is little danger from heating and sweating when the final covering is applied. As soon as the nights become frosty, apply a heavy layer of straw, so that when compacted with soil it will be about six inches thick. On top of the straw apply a six inch layer of soil. Before the ground freezes too solid, apply another heavy layer of straw and a similar one of soil. Ordinarily, two heavy layers of both straw and soil furnish sufficient insulation; but where extremely cold weather prevails, a third layer may be advisable. When sound STORAGE HOUSES PROPER 225 potatoes are pitted in this manner, there is practically no risk in- A'olved, as they are almost certain to come out in good condition in the Spring. The advantage of pitting potatoes is that it is a cheap form of storage. Fig. 114. — A good example of a sod-walled potato storage house near Greeley, Col This house is provided with ridge and side ventilators. The disadvantage of pitting is that in severe weather the pota- toes are not accessible, consequently any sudden rise in market prices cannot l)e taken ndvantage of by the grower. Fig. 115. — One of ths cheaper types of partially ; with earth retaining walls and side roof openings whirh may bciisdl for tillint^ the storage space or for ventilation. In the Greeley, Col., district. Generally speaking, pitting is not to be recommended, except where no other storage facilities are available. Storage Houses Proper. — In deciding what particular storage house is most suitable to one's needs, the following factors should be considered: 226 TYPES OF STORAGE HOUSES (a) The temperature and precipitation likely to occur during the storage period; (b) the character and cost of the materials involved; (c) the nature of the soil and drainage; (d) tlie stor- age period. It is apparent to the reader, that, in the arid and semi-arid regions of the West, a materially different type of construction from tlint in use in the rain-belt section of the East might be permissible. •^ ■_ ..tt'..'^ -"{l'^ ' ' ? \NX. F "X^^ ■:^s^^^^ ^K^T:£!^-a^iKr^^^^l^0Skf^ Fig. 116. — A well-constructed storage house of the partially sunken type with side and end walls of stone. Note heavy pole rafters covered with woven fence wire ready to be covered with straw and soil. In the Greeley, Col., district. The Dugout or Cellar Type of Storage House. — In the cen- tral and western ])ortions of tlie United States, tlie dugout or cellar type of storage house is almost the only kind employed in the storage of potatoes. It is found in its most primitive state in the arid and semi-arid regions of the West, and in its highest state of development in the north central tier of states where the heavier rainfall makes water-tight roofs a necessity. Location and Construction. — The storage house should, when- ever possible, be located conveniently to the dwelling house, be- cause, in very cold weather, it usually requires rather close attention LOCATION AND CONSTRUCTION 227 to guard against the entrance of frost. Where side-liills, knolls, or what are termed in the West "hog-backs," consisting of a narrow and usuall}^ short ridge of land, are available, it is advisable to take advantage of them, as by their use better drainage and a ground level entrance at either or both ends of the cellar can be secured (Figs. Ill to 119). Where the topography of the land is \ i Roof COn'3!'3tS of up covered with pine Fig. 117. — A cheaply construct i ( u rough poles restinpc on the ground dii . ^ .jip. .n 1 b\ ikIkcjjoI needles. Such a type of storage house would not be buitable where extremely low tempera- tures prevail. such that it does not furnish these natural advantages, level land may be used, provided good drainage can be secured. In this case, the excavation may vary from practically nothing where surface drainage must be depended upon, to five or six feet where there is good natural or artificial drainage. The average depth of the ex- cavation for the cheaper structures of this type, when erected on level land, does not exceed three feet. The soil removed from such an excavation, particularly if the structure is wide, provides ample 15 228 TYPES OF STORAGE HOUSES the side and end walls material for banking the side and end walls as well as for a roof covering. Where the soil is of such a character as to remain intact, and an excavation of sufficient depth can ])e made, it is allowed to form the side, and in some cases the end walls; the roof being supported by plates resting on the soil and an occasional post to relieve the roof i)ressure. In such cases, the outward thrust of the roof is Fig. 118. — A storage house in process of construction at Aberdeen, Ida., showing side walls and roof covered with woven wire fencing and ventilators in side of roof. cared for by cross-tieing the rafters with boards. Where the earthen bank of the excavation serves as walls to the storage struc- ture, it is better to support the plate entirely with ])osts recessed into the earthen walls at sufficiently close intervals to afford the necessary strength, (Fig. 121). Where the storage cellar is only partially below the level of the ground, the walls are variously constructed. In the cheapest type noted, both side and end walls above ground were constructed out of a tough sod of sedges or cat-tails cut to uniform size and laid up in brick fashion. These walls were two feet or more in thick- ness. The sod walls supported the plates and roof in practically WALL CONSTRUCTION 229 the same manner as in the case of the solid earthen-walled struc- ture (Fig. 114), Another cheap structure is that shown in figure 117. In this instance the excavation was not over two feet, and the roof consisted of rough poles covered with a heavy layer of pine needles. Such a storage house has little to recommend it, except that of heing a temi)orary makeshift to tide over a short storage period where the climate is reasonably mild. Roof Construction. — The roof of the cheaper types of houses is usually constructed out of undressed poles, which may be laid sufficiently close togpfhor to serve as a support for a brush or straw Fig. 119. — Side view of the house sh straw and soil and ventilators capped. n in Figure covering, over which a heavy layer of soil (6 to 10 inches) is placed. In the better constructed houses in the semi-arid regions, heavier and more substantial rafters are used, and they are spaced about twelve inches apart. After the rafters are in place, a heavy woven wire netting is stretched over them and nailed in place, (Figs. 116 and 118), and over this tlie usual straw and earth covering is applied. Where a side hill or a "hog-back'' is available, the cut or excavation may be six to ten feet in depth, depending on the size of the structure. Such a site makes it ])ossible to provide a ground level entrance, at one end of the storage house in the case of the side hill, and at both ends when advantage can be taken of a "hog-back" (Fig. 113). Wall Construction. — In addition to the cheaper types of wall construction previously mentioned, it is well to consider those of a more permanent nature. These may consist of rough or dressed 230 TYPES OF STORAGE HOUSES posts set from four to six feet apart, covered on the outside with rough poles, lumher or heavy woven wire; or they may be con- structed of masonry or concrete. I'he style of wall construction adopted is very largely a matter of choice or necessity. Where first cost is not a serious consideration it is, without doubt, more economical to build a substantial structure. The grower should not, however, lose sight of the fact that the cheaper house, if carefully built, will provide as good storage as the more expensive one as long as it lasts. A partially sunken house is sliown in figure 132. In the humid regions of the north central and eastern portions of the United States, where heavy rains would render straw and Fig. 120. — A frontal view of the completed potato storage house (Fig. 118) showing driveway entrance and ventilator caps raised on left side. earth-covered storage houses unsatisfactory, they are constructed with a water-tight roof. Generally, the roof is covered with rough lumber, tar paper and shingles. Occasionally, it is sheathed with matched lumber on the inside. This treatment provides a fairly well insulated roof which in winter requires no additional protection, except during extremely cold weatlier, when a light covering of straw or strawy manure is advisable. The wall construction of the water-tight roof storage house need not necessarily differ from that of tlie semi-arid region type except that, on account of the heavier rainfall, it must be built sufficiently strong to prevent a cave-in. Where first cost is subsidi- ary to durability, it is generally advisable to use a better class of luml^er than the rough undressed ])oles. It may even be economy, VENTILATION AND LIGHTING 231 where the materials are available, to construct the side and end walls of concrete (Fig. 123). In some of the better type western potato storage houses observed, the posts were faced on two sides and the walls as well as the roof were covered with woven wire and straw, (Figs. 118, 119 and 120). The use of straw on the roof, especially when the rafters are spaced and covered with woven wire, serves not only as a protection Fig. 121. — View showing earthen wall with plate supporting posts recessed into the bank. On the Sweet ranch, Carbondale, Col. against heat and cold, but is also a medium for the absorption of moisture given off by the tubers in the process of transpiration and respiration. There is no drip from such a roof. Entrance Way. — Whether the entrance to the storage cellar is for team or man, on the level or an incline, (Figs. 113 and 120), it should be provided with two sets of doors with a vestibule between (Fig. 113) in the case of a ground level entrance; or bulkhead doors where it is not (Fig. 120). Ventilation and Lighting. — Ample provision should be made in all dugouts or storage pit cellars for ventilation and lighting, 232 TYPES OF STORAGE HOUSES where electric lighting is uot feasible. Many styles of ventilators may be found, but those shown in ligures 114, 115, 118 and 1:^5 are most favored. A ventilator should be so constructed that it possesses ample size to admit an abundance of air, and at the same time be provided with a swivel or slide damper which may be closed in severe weather. A shaft with an interior diameter of 12 by 13 or 13 by 16 inches should be sufficiently large. Those with hinged caps to exclude rain, snow, or frost, seem to be preferred. As a rule, the ventilators are placed along the ridge of the roof, altliough numerous structures have been noted in which they were constructed about midway between the ridge and the plate. See figures 118 and 123 for both })ositions. V Fig. 122. — Partially sunken storage house with concrete side and end walls. Jerome, Idaho. To insure uniform ventilation, they should be sjjaced from ten to twelve feet apart. Interior Arrangement. — The interior arrangement of the stor- age cellar is very largely governed ])y its size and character. Where no driveway entrance is provided and the house is narrow, say 13 to 20 feet, the entire space is used for storage purposes. The dirt floor may be left uncovered; or it may be floored over with rough luml)er or cemented. In some of the better tyj)es of storage cellars in which there is a central driveway, the storage bins on either side of it have venti- lated wooden floors laid on Joists. The joists, being placed at right angles to the driveway, provide an open space between the floor and the earth beneath, and this, as Avill be seen later, furnishes an open and unrestricted circulation of air beneath the bin, (Fig. 109). Where posts are used which are faced on two sides, the THE INSULATED STORAGE HOUSE 233 inner face is boarded up with three or four-inch strips of lumber, leaving an inch space between each two strips. The division walls between the bins are also ventilated, in the manner described for the ventilation of potatoes when stored in large piles. With such a type of bin construction, a free circulation of air is possible on all sides. Of course, it is realized that the extra expense involved in bin construction of this sort is considerable; and it is probably not wholly justified, except for the storage of seed stock, or in seasons when frequent rains during the harvesting period make it impossible to dry the tubers properly before storing them. Under such conditions, the ventilated bin is decidedly superior to the ordinary type. Fig. 12^. — Potato storage house with concrete walls, straw and earthen-covered roof plus a superimposed wooden shingle-covered roof. Greeley, Colorado. Where no provision is made for a driveway into the storage cellar, either because it is too narrow or for any other reason, the potatoes may be spouted into the cellar through the trap-door openings in the roof, (Figs. 126, 127 and 128). This method of filling the storage cellar is a material saving of labor, and, where a blanket or apron is used in lowering the potatoes from the spout to the floor, they sustain no more mechanical injuries than when unloaded directly from the driveway, or carried in by hand. The Insulated Wooden Potato Storage House. — This type of house is not used very extensively. It is better adapted to southern than to northern climatic conditions. The construction feature of such a storage house is the thorough insulation of its walls, ceilings, doors and windows, (Fig. 129). 234 TYPES OF STORAGE HOUSES The type of house recently described by Thompson- for the storage of sweet potatoes will serve equally well for the Irish potato, but, in the case of the latter, does not require artificial heat to ripen the tubers. Storage houses of the type under consideration must, in the North at least, be provided with facilities for heating them in extremely cold weather. This may be done with an ordinary heating stove. They are not to be recommended for northern con- ditions, nor advocated for the South, except in localities where poor drainage conditions will not permit of the dugout or cellar type of storage house. They are not recommended on account of their greater cost of construction, and also from the fact that they do •SiSptllQlEl ■ Fig. 124.— a typical Hor basement cellar. Glyndon, Mir Kivcr \alley potato warehouse with : not furnish as good storage as a ])roperly constructed cellar storage house. The Aroostook, Maine, Type. — In northern Maine, particu- larly in Aroostook County, a type of potato storage house has been developed which may be said to be exclusively confined to Maine. While in a sense it is a cellar storage house, yet viewed from another standpoint it is more, because the true Aroostook storage house includes a superstructure over the cellar. It is always Cvonstructed on a side hill or knoll, and is always provided with a ground level driveway into the l)asemcnt, and at the opposite end has a driveway into the superstructure above, (Figs. 130, 131 and 132). Construction. — A considerable proportion of these storage houses are constructed with concrete basements and always with a wooden superstructure. When the basen;ent walls are not built INTERIOR ARRANGEMENT 235 of concrete, they may consist either of a masonry wall of stone, a dry wall, or a wooden wall constructed with posts and rough siding, or it may consist entirely of rough posts. The floors may or may not be cemented. Usually, the storage space is covered with a tight wooden floor laid on joists. The basements are usually of good depth, 8 to 13 or more feet, and their capacity ranges from 2,000 to 10,000 or more barrels. Generally speaking, their construction is faulty with respect to ventilation, only an occasional one being provided with means for ventilation, other than through trapdoors in the upper floor. The storage house with ventilator, shown in figure 130 was the only one the writer had noticed ])rior to 1917. See the ventilators in figure 133. Fig. 125. — A 100,000 bushel potato warehouse at Lariuiore, N. D. In storing the crop in the basement, the bins are partially filled from the lower floor, the balance being put in from above, through trapdoors on either side of the driveway and over the bins below. When the house is built with a central driveway, it may also be filled in the same manner. In addition to serving a useful purpose in filling the bins and protecting the potatoes from inclement weather, the wooden super- structures of these storage houses have various uses, such as the housing of farm implements, barrels, sacks, fertilizer and other sup])lies; or they may serve for the storage of hay or grain. Interior Arrangement. — Broadly speaking, the interior ar- rangement of the liasement is dependent on whether it is con- structed with a central driveway, or whether the entrance is at one corner of the building. A basement with a central driveway has bins on either side, whereas those with an entrance at one corner 236 TYPES OF STORAGE HOUSES vary considerably in their bin arrangement, depending on whether one or more varieties are l^eing grown and stored; figures 130 and 131 give a very good general idea of the exterior appearance oi" the Maine type of storage house. The Artificially Refrigerated Potato Storage House. — This type of storage house, for potatoes at least, can hardly be said to be in existence. So far as we are aware, the present use of arti- ficially refrigerated storage houses is practically confined to the holding of northern grown seed potatoes in cold storage for second crop planting in the South, and to the temporary holding of table stock in laro'o distributing centres. Fig. 12t). — A good example of the type of storage house in use in the Red River Valley in Minnesota and North Dakota. This house has a water-tight roof with several openings in it to permit of spouting the potatoes into the storage bin. Sabin, Minn. Ammonia System. — The system of refrigeration used in the cold storage plants employed for this purpose is known as the "ammonia system." The temperature at which potatoes are held in this type of storage is usually from 32 to 34 degrees F. While there is probably little demand for the artificially refrig- erated potato storage liouse in the North, it is a questionable point whether community cold storage plants could not be profitably employed by the southern potato truck grower. If such houses were available in the South, the present practice of moving seed stock from northern Maine during the months of January and February, with its attendant risk of frost injury could be avoided, as, wath cold storage facilities, the seed potatoes could be shipped in the Autumn. At the present time, the potato storage houses of the South do not compare at all favorably with those of the North, being for tlic most ]iart of the dugout type and constructed with BRINE SYSTEM 237 little head-room. They are wholly inadequate for the holding of northern grown seed and, as a result, the stock held in them from November to February is usually rather badly germinated. All of these troubles could be avoided through autumn delivery of northern seed stock and its transference to the cold storage house. Such a change in time of delivery would enable the grower to purchase his seed at a reduction in jirice over that of mid-winter delivery more than sufficient to offset the cost of storage. Brine System. — One of the more recent tyjoes of storage houses, which may have a place in the storage of potatoes outside of the colder jiotato-growing regions, is that known as "the Cooper system Fig. 127. — Spouting potatoes into storage cellar through chutes in the Greeley, Col., district. of brine circulation." In this system, ice and salt are used as a substitute for ammonia in cooling the brine. In "Practical Cold Storage," pp. 660-662, Cooper describes the process as follows : "In the Cooper gravity brine system, the tank, which contains the ice and salt, and the tank coils, or primary coils as they are called, are located at a higher level than the secondary coils which do the air cooling in the rooms When the tank is filled with ice and salt, the brine standing in the primary or tank coil is cooled, by contact with the ice and salt which surround the pipes, to a lower temperature than the brine contained in the secondary coils. At the same time, the brine from the secondary coils rises into the primary coils, where, as it is cooled, it repeats the circuit The term 'gravity,' as applied to this system of brine circulation, refers to the cause of circulation which is owing to the difference in 238 TYPES OF STORAGE HOUSES specific gravity (weight) between the cokl brine in the primary coils and the comparatively warm brine in the secondary coils. The temperature of the circulating brine will range from zero to 20 degrees F. It is comparatively easy to cool a room to 10 or 12 degrees F. with the Cooper brine system." This system of refrigeration was used 1)y the United States Department of Agriculture in the storage of potatoes from 1911 FiQ. 128. — Method of filling a storage house in the Greeley district through openings in roof. Driveway partially filled by spouting potatoes through roof openings. to 1918 and it proved very satisfactory. It was found possible, with proper attention, to maintain the temperature of the storage room at practically the same degree for weeks at a time, as shown by the thermograph record sheet (Fig. 134). Cost of Construction. — Owing to the wide variation in cost of building material, and the price of labor in different sections of the country, cost figures concerning the construction of any par- ticular type of house must, of necessity, be more or less general in their character. Naturally, the type and the size of the house is COLORADO 239 largely determined by the character of the material available, the climatic conditions and the storage cai)aelty required. In deter- mining the size of storage cellar required to house a given quantity of tubers, the estimate should be based on 40 pounds of tubers per cubic foot of available storage space. Figured on this basis, a bin 10 by 10 feet square, filled to a depth of six feet, has a storage capacity of 400 bushels, or an average of four bushels for every square foot of floor space. Fig. 129. — A good example of an insulated wooden structure used for the storage oi potatoes in some localities in Michigan. Colorado. — The following information concerning the cost of construction has been very kindly furnished by practical growers. The first data presented are those given by Messrs. Lou D. and Frank E. Sweet, of Carbondale, Colorado, and relate to the potato storage house shown in figure 112. The capacity of this house is stated to be from 13,000 to 25,000 bushels, depending on the depth to which it is filled, as well as storing in the driveway. Its cost is estimated at $1,000. This cost did not include the lumber cut on the surrounding mountains, for which there was no other cost than that of cutting and hauling. Allowing $300 for the rough timbers used, it would bring the actual cost to about $1,300. On this basis, the initial cost of providing storage for one bushel of 240 TYPES OF STORAGE HOUSES potatoes reduces itself from 10 to 5.2 cents per bushel, depending upon the depth to which the tubers are piled. Assuming that the average life of such a structure is ten years, the actual per bushel cost of storage is one cent and .53 cent respectively. Of course, these figures do not take into account interest charges on the investment. Fitch^ states that the first cost of storage in an average grade potato cellar is about 20 cents per hundredweight, or 1.2 cents per bushel on a ten-year basis. He further intimates that this cost can be reduced to 7 instead of 20 cents per hundredweight if little Fig. 130. — Exterior front view of a Maine type of storage liouse. This particuiar house is an exception to the general rule in that it is provided with a roof ventilator. regard is given to the permanence of the structure and farm labor is utilized in its construction. Minnesota. — Henry Schrocder, of Sabin, IMinncsota, sul)mitted the following figures concerning his storage cellar shown in figure 126. This house is constructed with wooden walls, and a water- tight roof. The walls are four and a half feet below the surface of the ground and extend four feet above it. Its dimensions are 20 by 100 feet and it has an approximate storage capacity of 10,666 bushels, if figured on the basis of its full capacity of eight feet in depth. Tt was constructed at a cost of $1,200, or an average initial cost of 11.25 cents per bushel, or 1.125 cents on a ten- year basis. Maine. — C. C. King, of Caribou, Maine, submitted the following estimates on a Maine type of storage house, 40 by GO feet, having a storage capacity of 4,250 to 5,500 bushels, the cost of wliich he MAINE 241 places at $3,500. The initial cost of storage in this case is 64 to 82 cents per bushel. The longer lil'e oi' such a structure tends to reduce the average cost of storage over a period of years. King further states that the same house could be built Avithout a con- crete cellar, but resting on concrete piers, for about $2,500 to $2,700, According to King, the most common size of storage house in Aroostook County, Maine, is tlie 35 by 60 feet or the 40 by 50 feet. Fig. 131. — Exterior rear view of same house showing driveway entrance located in side of building at the rear end. George E. Howard, of Dover, Maine, says, "I am satisfied tliat the ordinary potato storage house, when built 40 by 60 feet with ]tosts 16 feet or more, can be erected today for five and a half cents per cubic foot of contents, (approximately $2,100), figured from the bottom of the sills to the top of the plate. To this must be added the cost of the basement below the sills. If concrete, it Avill cost from $5 to $7 per cubic yard of concrete, depending upon the convenience of sand and gravel." He further says, "We have one near here 30 by 40 feet with 12-foot posts and 8-foot basement, 4 feet of which is below the level of the ground, which cost, in- cluding basement, $1,400." 242 TYPES OF STORAGE HOUSES It is evident from the foregoing figures that the Maine type of potato storage house is a much more expensive one tJian that of the dugout or cellar type. But if its durability is considered as well as the storage room i)rovided in the superstructure, the ulti- mate cost of storage is not so very much greater. The above figures are pre-war estimates. Idaho, — In the fall of 1914, the Department of Agriculture built a potato storage cellar at Jerome, Idaho, in which some new I I Fig. 132. — The more common type of the better class of Maine potato storage houses, with rear end driveway. features of interior construction were eml)odied. The structure is 30 by 50 feet in dimensions with a central driveway. The side and end walls are of concrete, eight inches in thickness with 12- inch footings, and eight feet in height. The even span roof is of wooden frame construction, covered in the usual way with woven wire, straw and earth. The interior arrangement of this cellar differs from that of any other noted in that it is provided with examination and disinfect- ing rooms, at one end of the cellar each approximately 10 by 10 IDAHO 243 feet in diameter. The balance of the cellar is divided into eight binS;, four on either side of the driveway, each 10 by 10 feet. The wooden floor of these bins is a removable one, being constructed in three sections, each of which consists of 3-inch strips of board nailed to cleats, with 1-inch space between the strips. These floor sections are supported by 2 by 6 inch joists which, in turn, rest on three 4 by 6 sills. The 2 by 6 joists were given an inch shoulder on the supporting sills, thus providing a 5-inch opening into the driveway, as the joists are at right angles to it (Fig. 109). The interior face of the concrete side and end wall of the storage cellar I'iG. 133. — Potato stoiago liousc trtctt-d by the U. S. Dept. of Agiicultuie on Aroostook Farm, Presque Isle, Me. Note large roof ventilators or cupolas. Small greenhouse on left is used for starting the seed potatoes. l)roper is furred with 2 by 4 studding, spiked to the 4 by G sill below and to the rafters above. The studding is spaced 33 inches apart in the clear and is covered to the height of six feet, with 4-inch boards spaced one inch apart. The slatted division walls of each bin are double when in place. They are constructed in sections similar to the floor, and are attached at each end to supporting posts. The cleats on w^hich the 4-inch board slats are nailed come opposite to each other when in place, thus insuring a 2-inch air space in the walls. This type of floor, wall, and partition construc- tion afi'ords a complete circulation of air around each bin, which is especially desirable for the storage of seed stock. 16 244 TYPKR OF STORAGE HOUSES -C I QUESTIONS ON THE TEXT 245 QUESTIONS ON THE TEXT 1. What is the most primitive type of stoi-ageV 2. Describe the method of pitting- potatoes. 3. What is a safe limit in size? 4. What sliould be tlie shape of the pile? f). Why should there be some provision made for ventilation? fi. Give successive steps in the pitting of potatoes. 7. What is the advantage of the pitting system? The disadvantage? 5. What factors govern the determination of the right type of a storage house ? 9. Where is the dugout or cellar type of storage house most commonly employed ? 10. What are the chief things to consider in the location of such a storage house ? 11. Describe the construction of the house, viz., the cellar, walls, and roof. 12. What further suggestions are given regarding more expensive and durable walls? 13. What modification in roof structure is necessary in the liuinid sections of the north central and eastern states? 14. What fiuiction besides insulation does the straw covered roof perform? 15. ^^'hat provision should be made to exclude either heat or cold from the entrance way? IG. How is ventilation usiuiUy provided in the storage house? 17. Describe interior arrangement vi house. 18. Describe a ventilated bin 19. Where no provision is made for a driveway into the storage house how are the potatoes put into it? 20. Describe the insulated wooden storage house. Where is it usually found ? 21. Why is the type of storage house now advocated for sweet potatoes not satisfactory for Irish potatoes? 22. In what way does the Aroostook, Maine, type of potato storage house difl'er from those previously discussed? 23. How is this type of house usually constructed? Give sizes. 24. How are the basement bins usually filled? 25. Of what use is the wooden superstructure? 26. To what extent is artificial refrigeration employed in the potato storage house? 27. What advantage has it o\er ordinary storage? Where most apparent? 28. What are the present storage facilities in the South? 29. Describe the "Cooper brine circulation system?" 30. Is the Cooper system a satisfactory one? Give arguments for and against. 31. What is the usual method of determining the storage capacity of a given basement or bin space? 32. Give the cost data on the construction of the cellar type of storage hotise ? 33. Does the above cost estimate represent the present sum necessary to construct such a house? How would it ditt'er? 34. Give Fitch's cost estimate on an average grade potato cellar? 35. What was Schroeder's estimate of cost of constructing a 20 by 100 feet storage house in the Ited River Valley? 246 TYPES OF STORAGE HOUSES 36. How do King's and Howard's estimates on the Maine type of storage house compare with those of the preceding ones? 37. What new features were introduced in the interior arrangement and bin construction of the Jerome, Idaho, potato storage house? QUESTIONS SUGGESTED BY THE TEXT 1. Make an estimate of the number of local storage houi^es of each of the five types. 2. Describe some of these which you have seen. ,*{. Visit a cold storage plant in your section. Study its advantages and disadvantages for potato storage. 4. If space is rented in this house, calculate the cost per bushel for storage, f). Make an estimate for constructing a liouse, locally, of one of the types 2, 3 or 4. References Cited 1. Fitch, C. L. 1910. Productiveness and degeneracy of the Irish potato. Col. 8ta. Bui. 176: 47, Nov., 1910. 2. Thompson, H. C. Storing and marketing sweet potatoes. [7. ,S'. Dept. Agr. Farmers' Bui. 548: 1-15. CHAPTER XV POTATO DISEASES AND THEIR CONTROL The potato, like most other agricultural plants, has its parasites which prey upon its aerial and subterranean parts, causing more or less severe injury to the plant itself and to its resultant tubers. There are also a number of obscure maladies affecting the potato plant which as yet cannot with certainty be classed as parasitic diseases, or for that matter, even as diseases in the strict sense of the word. These types of potato troubles have, for the lack of a better understanding of them, by the pathologists, been designated as physiological troubles. There is, however, a growing feeling in the minds of some of the leading pathologists and potato specialists that some of these maladies will in the end be found to be due to parasitic organisms. Losses Due to Diseases. — It is impossible to estimate with any degree of accuracy the annual losses sustained by the potato growers of this and other countries from diseases and physiological troubles affecting the potato plant. It has been estimated that the potato growers of 'New York State in 1903 sustained a loss of nearly $10,000,000 from the late blight alone^^ Losses of $100,- 000,000 are by no means infrequent, and it may be assumed that, if all the facts were known, it would show a much larger loss than the amount mentioned. These figures are sufificient to emphasize the great economic importance of these diseases, insofar as they reduce the money value of the potato crop of the country. DISEASE CLASSIFICATION.— The following classification of diseases according to causes ivith preventive measures and remedies is sub- mitted in the hope that it toill afford a convenient and ready reference to the more important diseases of the potato. Parasitic Diseases Remedial and Preventive Measures. Fungous. 1. Early blight Spraying plants with Bordeaux mixture 2. Late blight for 1 and 2. Use of disease-free seed (2). 247 248 POTATO DISEASES AND THEIR CONTROL 3. 4. Fiisarium Fusariuin (a) F. (b) F. (V) F. (d) F. (0) F. wilt dry rot cu 711(1 rtii radicicola oxijsporum hijperoxiispnrum discolor var. siil- _ phureum (f) F. f richothcciodcs Vortici ilium wilt G. IJhizocton Common i ia scab S. 10.' Silver ^ci Wart Leak irf It :trlrriic mold 17. I'owdery scab Use of disease-free seed. Soil sanitation : — rotation of crops and use of disease- free land where possible. Remove all wilt infected plants (3) and (5). Care- ful handling of tubers. Disinfection of storaji^e house and low storajre temperature, 34° to 36° F. in case of 4 (f). Troaiment of seed in corrosive subllinalc or formalin solutions, preferably the former. Lse of clean seed; soil sanitation: — rota- tion, etc. Use disease-free seed. Plant imnume vari- eties in case of ( 'J ) . Reduction of mechanical injuries of tubers and rejec- tion of all injured stock in shipments in case of ( 10) . Treatment of seed in corrosive sublimate or formalin solutions. Use disease-free seed. Remove infected plants and tubers. Use disease-free seed. Soil sanitation: — rotation, etc. Remove infected plants. Use disease-free seed. Control insect pests Remove all diseased plants. Treatment of seed in corrosive sublimate solution. Plant clean seed stock. Soil sanitation. 18. Spindlin.u' 19. Net necro; 20. Curly dw. 21. Tip-burn 22. Arsenical sprout is rf Non-parasitic Diseases l^se stron OC K Fig. 147. — Cross sectiona of tubers affected with Rhizoctonia Maine Station. a definite system of crop rotation and in avoiding, as far as possible, the use of land known to be infected with the scab organism for potatoes. In view of the fact that yirgin soil may be infected with the scab organism, the use of new land does not offer an absolute guarantee of freedom from infection, though as a rule it does produce clean seed. Thus far, no practical method has been discovered for destroying scab organisms in the soil. It is known, however, that a soil giving an alkaline reaction is much more likely to be infected with scab than one that is slightly acid. Appli- cation of lime to soil intended for growing potatoes is not, there- fore, recommended unless it is known that the soil is too acid to SILVER SCURF 267 permit of the development of a satisfactory crop, or that it is known to be free from scab infection. Scab infection may be controlled to some extent by turning under green rye, clover, alfalfa, or other suitable green manuring crops, as the acidity in the vegetable matter turned under tends to make a slightly alkaline soil neutral or even slightly acid. Heavy applications of fresh horse manure in the spring before planting the crop seems to aggravate the scab V---.- Fro. 148.— Stem roots and tuhors sfiowing common scab infection. Maine Station. when it is already in the soil. This is due to the fact that the manure furnishes an excellent growing media for the potato scab organism. SILVER SCURF It is supposed that tlie silver scurf disease, Spondylocladium atrovirens, is of recent introduction from Europe, but it is rather doubtful if this supposition is correct, as the rather common inter- change of varieties between this country and Great Britain in 268 POTATO DISEASES AND THEIR CONTROL former years must have resulted in the introduction of most of the less easily recognized diseases affecting the potato tuber. Fortun- ately, the disease known as silver scurf is not a very serious pest as compared with many others. Description. — Tubers infected with silver scurf first develop dark spots or areas on the surface of the tuber. These areas soon begin to show the fruiting or spore-1)earing hypha?, which appear to the unaided eye as dark points or protrusions. Under favorable Fig. 149. — Tuber badly disfigured with common scab. conditions, sucli as heat and moisture in the storage bin, the newly develoi)ed spores may cause fresh infections. The fungus seems ■ to injure the skin, and possibly the cells beneath, to a sufficient extent to cause a more rapid loss of moisture, resulting in slightly sunken areas. The skin loses its normal color and takes on a silvery cast, thus giving to the fungus the name of silver scurf. Preventive Measures. — Seed treatment appears to be ineffec- tive, hence the only preventive measure possible is that of the uf-o of disease-free seed. POTATO WART DISEASE 269 POTATO WAET Dlf^EASE The occurrence of this disease, Chrysophlyctis endobiolica, was first noted in North America, in October 1909, by Gussow,^ the Dominion botanist of Canada, who recognized its presence on some specimens of tubers sent to him -for identification from a locality in Newfoundland. Its occurrence in the United States was first recognized by Professor J. G. Sanders, of the Pennsylvania Depart- ment of Agriculture, at Harrisburg, to whom infected tubers were sent from Highland, Pennsylvania, in September 1918." A careful survey of this region, immediately after the recognition of its presence, resulted in finding it in twenty-six towns and villages in lower Luzerne County. It now seems probable that the disease was introduced into this mining section of Pennsylvania through the importation from Euro])e of twelve carloads of German grown potatoes in 1913. More recently it has been found in some mining towns in West Virginia and Maryland. It was originally described in Hungary in 1896. Description. — The wart disease of the potato is caused by one of the lower orders of fungi. It attacks all underground portions of the plant, but more especially the tubers. Infection of the tubers is usually through the eye. The first visible symptoms of infection are the presence of tiny wart-like growths, which rapidly enlarge in size until, in severe cases, the tuber is literally converted into a huge mass of warty excrescences, which bear little, if any, resemblance to a potato. In such instances, and even where infection is less severe, the tuber is valueless for table purposes. The parasite reproduces itself by means of minute, yellow-covered, globular bodies called sporangia. These sporangia are born in great num- bers just beneath the surface of the wart. The summer sporangium is surrounded by a thin wall, while that of the resting or winter sporangium is quite thick. The former germinate as soon as mature, and the spores produced thereby may infect other portions of the same plant. On the other hand, the resting sporangia may remain inactive for a long period, probably several years. Each germinating sporangium releases a large number of microscopic, free-swimming spores which move about in the soil water. If these bodies fail to come in contact ^vith developing potato tubers, or tender portions of the plant which they are capable of penetrating, they die. 270 POTATO DISEASES AND THEIR CONTROL Preventive Measures. — The only effective preventive measures known are those of planting disease-free seed on non-infected soil; growing other crops on wart-infected land; or the employment of disease-resistant varieties. Fortunately for the potato industry, in wart-infected districts there are a number of commercial vari- eties of potatoes that appear to be entirely immune to the disease. Investigations thus far have indicated that varieties of the Irish Cobbler group, and \nth one exception, thus far, of the Green Mountain group, are entirely immune to the wart disease. So is Spaulding No. 4 or Rose 4. In Great Britain, rather extensive studies upon the immunity of the leading commercial varieties to the wart disease have been carried on at Ormskirk, Lancashire, England, for the past two seasons, with the result that they are now able to recommend quite a respectable number of wart immune varieties. Causal Organism. — The disease of potatoes commonly known as leak is, according to Hawkins,* probably caused by Pythium deharyanum. In 61 attempts, Hawkins succeeded in isolating the fungus from leak infected tubers a total of 49 times. This fungus was also found to be rather universally present in soil samples taken from various parts of the delta region, in the vicinity of Stockton, California; and the ai)plication of such soil to mechani- cally injured potato tuber tissues caused infections, from which the organism, P. deharyanum, was isolated. No cases of infection, either in the field or laboratory, were observed when the skin of the tuber remained unliroken. Action of the Disease on the Tuber. — The action of the organism on the tissues of the tuber, under favorable conditions, causes a rapid and practically complete breaking down of the cellu- lar structure of the tuber, and the resultant loss of its liquid con- tents. For this reason, the disease has been given the name "leak," that is, the liquid contents leak out. In discussing the losses due to the disease in the delta region of the San Joaquin River, Cali- fornia, Hawkins says, "The rot is manifest in hot weather, and appears soon after harvesting. As the potatoes in this region are sacked in the field and practically all shipped immediately, the disease is, therefore, first evident in the car or warehouse. In BLACKLEG 271 extreme cases a whole shipment may be so badly damaged as to be worthless." Preventive Measures. — As the disease is incapable of infecting uninjured tubers, the obvious preventive measure to be employed is that looking toward a reduction of cuts and bruises, resulting from the harvesting and handling of the crop. The universal prac- tice of the potato growers of this section of breaking off the knobs or prongy gro^vths, so common with the Burbank, is an undesirable one because it offers an entrance point for the fungus. As most of the digging is done by hand vnt\\ heavy five- or six-tined hoe forks, many tubers are injured by being pierced with one or more of the prongs, thereby inoculating the tuber with disease. Such injured tubers should not be sacked as salable table stock, because the chances are strongly in favor of such tubers decaying in transit, and others may become infected from them. All cut, bruised or pierced tubers should, therefore, be discarded as they are being sacked for market. BLACKLEG The bacterial disease of the potato commonly known as black- leg, Bacillus phytophthorus, is rather widely distributed throughout the potato-growing sections of the northeastern United States and Canada. So far as known, the first recorded occurrence of this disease was made by JonesP^ in Vermont, in 1906. It was noted in a field of Green Mountain potatoes on the Station farm. The seed used in planting this field had been purchased in Iloulton, Maine. Character and Appearance of the Disease. — In describing the character and appearance of the disease, Morse^^*" says, "Plants affected by blackleg are readily distinguished in the field by any close observer, even at a distance (Fig. 150). The affected plants appear more or less unthrifty and usually undersized, varying with the severity of the attack. The branches and leaves, instead of spreading out normally, tend to grow upward, forming a somewhat more compact top, frequently with the young leaves curled and folded up along the mid-rib. Later they become lighter green or even yellow, and the whole plant gradually dies. If the disease progresses rapidly, the stem may fall over quite suddenly and wilt, vni\\ very little previous signs of disease other than the upward trend of the foliage noted above. 272 POTATO DISEASES AND THEIR CONTROL "The diagnosis of suspected cases is easily confirmed by pulling u}) the aU'ected plants. Blackleg, as its name indicates, is charac- terized by a pronounced blackening of the stem below the ground, Fio. 150.— Potato plant affected with blackleg. Maine Sta. usually running up one, two, or even three inches above the surface. Sometimes, under very favorable conditions, i.e., continued wet, cloudy weather, especially where plants are growing on a naturally moist soil, the inky-black discoloration may follow up a portion of the stem for several inches a])ove the ground (Fig. 151). During SOFT ROTS 273 the active progress of the disease, the invaded tissues show a soft wet decay Usually, the seed tubers attached to affected stems are entirely decayed by a soft rot or have disappeared entirely. If young tubers have been formed before the complete invasion of the stem, they are occasionally affected in the same manner . . . . " The blackened area frequently extends up the stem a foot or more, or even to the extreme tip of the central stem. Extent of Loss to Crop. — The ex- tent of crop loss from blackleg is relatively small as measured by late blight, rhizoc- tonia or the fusaria diseases. Remedial Measures. — Treatment of seed in formalin or corrosive sublimate will destroy surface infection by spores. Preventive Measures. — Discard all tubers showing stem-end discoloration. Remove all diseased plants and accom- panying tubers, if any, as soon as they are noticed in the field. Strictly speaking, there is little excuse for any progressive potato grower having blackleg plants in his potato field, as strict observation of the preventive measures suggested will result in its elimination, since, so far as known, the disease is only transmitted tlirough infected seed. SOFT KOTS The soft rots of potatoes are caused by putrefactive bacterial organisms, of which Bacillus carotovorus is a good example. Generally speaking, these bacteria are incapable of infecting sound, healthy tubers. They may be regarded in the general category of wound parasites, or as parasites of plant tissues that have been injured through excessive moisture and heat combined which, literally speaking, asphyxiates the living protoplasmic contents of the potato 18 Fig. 151. — Potato stem com- pletely destroyed by blackleg. Maine Sta. 274 POTATO DISEASES AND THEIR CONTROL tuber, thus causing a rapid breaking down of the cell structure, which is further hastened by the putrefactive bacteria. All of these organisms convert the flesh of the tuber into a slimy and extremely ill-smelling mass of matter. Frequently, these putre- factive organisms follow late blight infection of the tubers. Preventive Measures. — The only preventive measures that can be suggested are those pertaining to soil sanitation, such as good drainage and aeration. BACTERIAL WILT The disease. Bacillus soJanacearum, commonly known as bacterial wilt, is one that affects practically all of the food-producing members of the nightshade family, such as the potato, tomato, eggplant, etc. Its occurrence is mostly confined to the southern United States. Symptoms of the Disease. — The first evidence of infection is a sudden M'ilting of the whole plant, or of one or more of its steuLs and finally the whole plant. For a time the wilted stems revive during the night, but gradually they lose their characteristic bright green color and become shrivelled and black- ened. An earlier examination of the vascular tissue of the stems would have shown a brownish discoloration somewhat similar to that caused by fusarium wilt. The exudation of tiny drops, of a dirty or yellowish-white-colored liquid, from the cut surfaces of the stem, identifies it as of bacterial origin. In the case of the potato, the discoloration extends into the roots, tuber-bearing stolons infecting the tubers and causing them to decay. Potato plants growing on virgin soil are more apt to become infected with this disease than those on old soil. As a rule it does not, in the aggre- gate, cause very much loss to the potato crop. Preventive Measures. — Eotation of crops, soil sanitation, good drainage and aeration will materially reduce infection from the bacterial wilt organism. STREAK Occurrence. — The disease kno\vn as "streak'' is tentatively classified as of bacterial origin, though as yet the causal organism has not been determined. It is not of widespread occurrence in commercial potato fields; in fact, it might be said to be rather uncommon outside of the large seedling collection of the United States Department of Agriculture, where it has occurred, with more or less regularity and in some instances severity, in certain hybrid STREAK 275 -f!»i/^ Fig. 152. — Potato leaf affected with streak. Note blackened veins and veinlets. (Maine Sta.) seedlings. It has also been noted by Orton^*^ in a field of Factors' at Puyallup, Washington, in September, 1914. Description. — Orton describes streak as follows : "Streak is first to be detected on the upper, full grown leaves of the potato plant 276 POTATO DISEASES AND THEIR CONTROL in the form of elongated or angular spots following the veinlets and invading the parenchyma (Fig. 152). While somewhat more con- spicuous on the upper side, these spots are also to be seen on the under side as narrow, discolored streaks along the veins. The typi- cal form may very quickly be recognized, and distinguished from the spots caused by early blight {Macrosporium solani) ; though the more diffuse spots of the streak resemble slightly the macro- sporium spots, particularly when the latter also occur on the same plants, as is often the case. "The destructive progress of the streak is rapid. Shortly after its appearance on the leaflets, as described, the petiole will be found affected and slightly discolored by longitudinal streaks. The peti- ole collapses, and the leaf then withers and hangs limp; or the petiole breaks at the point of attachment to the stem, and haugs by a thread in a dead and dried condition. Since it is the full grown leaves that are first attacked, there is, at this stage, a circle of dead leaves about a third of the way down from the terminal shoot, while the latter is still green. The hanging dead leaves are quite characteristic of the disease, while all the characters men- tioned form a picture that is quickly seen and well remembered. "A prominent characteristic of streak is the brittleness of the affected parts. The leaves break off very easily and the stem is also brittle "The stem begins to turn brown, and dies at a point below the tip. The upper leaves then ^dlt and die, and the disease progresses downward. Long faint brown streaks appear on the stems also. Apparently, the discoloration is Just below the epi- dermis but not in the vascular bundles. These brown strips arc not continuous from leaflet to petiole, nor from petiole to stem. There is no discoloration of the vascular bundles in the lower part of the stem or root, nor are there any other evidences of disease at the root. The several stalks in a hill die separately; all stages may be observed in one hill, from the first spotting of the leaves to the quite dead stalks No effect on the tubers has been found. The yield is reduced in proportion to the time of onset of the disease." Preventive Measures. — The only measure possible to take for the control ol' streak is that of rigidly removing all affected plants as soon as the disease is noticeable. The use of seed from fields known to be free from this disease is also desirable. SYMPTOMS OF THE DISEASE 277 Occurrence. — The disease of the potato known as Mosaic is a comparatively new one to American potato growers, having been first observed by Orton^* (p. 40) in northern Maine, in 1913, but was not found in Wisconsin, ' Minnesota, Colorado, a n d other western states during either 1912 or 1913. Accord- ing to Schultz, Folsom, Hil- debrandt and Hawkins,^' its reported occurrence in 21 states up to 1918 showed con- clusively that its distribution was rather general through- out the United States.- Symptoms of the Disease. — The S3^niptoms of the disease are far more pro- nounced on some potato vari- eties than on others. The mottled appearance of the foliage, Avhich characterizes this disease from that of others and from which it really derives its name, is marked in some varieties and not very noticeably expressed in others. For example, the disease is rather difficult to detect in the foliage of the Eural varieties, while in the Green Mountain and the Triumph varieties the (Maine sta.) mottled appearance of the leaves is strikingly apparent (Fig. 153). The mottling is due to a reduction of chlorophyl in localized areas over the surface of the leaf, giving it a mosaic or mottled appear- ance. Severely infected leaves become crinkled or rugose, with more or less dead tissue along the margin of the leaves. In the advanced stages of mosaic, the plants become much dwarfed in both stem and foliage. While the tubers from the mosaic-infected Fro. 153.— Plant affected with Mosaic. 278 POTATO DISEASES AND THEIR CONTROL plants transmit the disease to their progeny, the eye has been unable as yet to detect any symptom of the mosaic disease in the tuber. Character of the Disease. — Recognized as a transmissible para- sitic disease, but as yet, the pathologists have not succeeded in isolating the causal organism. It is strongly suspected by some that the mosaic disease is due to an ultra-microscopic organism. It is transmitted from diseased to healthy plants in the same manner and by the same plant lice as in Mosaic disease. It is also transmitted through infected tubers. Effect upon Yields. — The evidence at hand indicates that the mosaic disease does cause a material decrease in yields from that of healthy plants. Orton (I.e. p. 43) noted a difference in yield between 80 mosaic Green Mountain plants and 80 healthy plants of 22 per cent in favor of the latter ; while Wortley^^ claims a difference of over 100 per cent between 200 healthy and 200 mosaic-infected Triumph plants. Murphy^ ^ secured data on 682 diseased Green Mountain plants and a similar number of healthy plants adjacent to the diseased ones, and found that the yield from the diseased plants was only 58 per cent of the healthy plants. The data presented are sufficient to indicate a marked decrease in yield from mosaic-affected plants, thereby stamping the disease as one to which serious consideration should be given by those interested in the welfare of the })otato industry. Preventive Measures. — Owing to the nature of the disease, only preventive measures can be employed in controlling or holding it in check. The first of these is the elimination of all infected plants in the seed plot as soon as they appear; the second is that of keeping the plants as free from insects, particularly plant lice, as is possible; the third is that of isolating or procuring a mosaic- free strain of seed. As a matter of fact, however, the real problem is that of securing a mosaic-immune variety or strain of some of our present commercial varieties. LEAF-EOLL The leaf-roll disease of the potato has, until quite recently, been regarded as a non-parasitic type of disease. At the present time, it occupies about the same position in the minds of the pathologists as does the mosaic disease; it is probably transmitted from diseased to healthy plants in the same manner, though not necessarily by the plant lice or aphids. Symptoms of the Disease. — As its name indicates, the leaf- roll disease is expressed in a rolling of the leaves, a dwarfing of the PREVENTIVE MEASURES 279 plant, a yellowing of the foliage, and an upward rolling of the leaflets about their midrib. In advanced stages the leaves show a distinct tendency to point ^^pward, and quite frequently the upper and younger leaves show a more or less distinct pinkish or purplish tinge on their lower margin. The lower leaves are usually more or less thickened and leathery, and, when handled, make a crackling noise. Distribution. — Leaf-roll is more or less general in the north- eastern portion of the Ignited States and Canada, and may be found (A) (B) Fig. 154. — Effect of leaf-roll disease upon tuber production. (A) — Healthy plant. (B)— Diseased plant. (Photo by E. J. Wortley.) here and there in Avestern potato fields. In some sections of the East, it is becoming so abundant as to cause concern on the part of those interested in the production or purchase of high grade seed. Effect upon Yield. — The tubers from leaf-roll plants, at least in the more or less advanced stages, are greatly reduced in size, and are usually borne very close to the main stem of the plant rather than on medium-long tuber-bearing stolons (Fig. 154). Preventive Measures. — The same preventive measures should be employed for the control of leaf-roll as in the case of the mosaic disease. 280 POTATO DISEASES AND THiaR (X)NTROL POWDERY SCAB Occurrence. — The existence of this disease, Spongospora suh- icrrancn, was unknown in the United States prior to papers pub- lished by Morse^- and Melhus^^ in 1913. It was first reported in North America by Gussow^^ in February, 1913. It is impossible to more than conjecture the length of time powdery scab had been present, in the potato fields of Maine and the Maritime Provinces of Canada, prior to 1913. A survey of northern ]\Iaine, in 1914 and 1915, disclosed the fact that it was widely distributed in Aroostook Count}^, and, judging from the virulence of tuber \ / \ .-. Si Fig. 155. — Stem and roots of potato plants affected with powdery scab. (Maine Sta.) infection in localized areas and on certain types of soil, one is forced to the conclusion that powdery scab was not a new disease in that region, except in point of observance. Melhus"'' says: "It seems probable that it was introduced with the heavy shipments of foreign potatoes in 1911." The correctness of this supposition is hardly borne out by subsequent observations regarding its rather wide- spread distribution. Probably no other disease, outside that of the potato wart, has caused more widespread alarm as to the dire injury it would occasion to the crop, if vigorous measures were not takeis to stamp it out. IIa])j)ily, a closer acquaintance with this disease has resulted in our finding that the powdery scab only thrives under exceptionally favorable environmental conditions. It does not DESCRIPTION or THE DISEASE 281 thrive in warm climates and, even when scab-infected and untreated seed stock is planted in the South, the chances are strongly in favor of its not showing any evidence of powdery scab infection. Distribution. — According to Melhus, Eosenbaum and Schultz,'-"^ powdery scab has been found in the following states: Maine, New York, Florida, Minnesota, Oregon and Washington. It is also known to occur in the Maritime Provinces in Canada and in British Columbia. Its general occurrence in northern and central Europe and the British Islos is well known. Description of the Disease. — The powdery scab disease, like that of the common scab, lives over in the soil. It attacks the ^^^ ft H^^^ Fig. 156. — Potato tubers showing an abundant infection of powdery scab. (Maine Sta.) subterranean parts of the potato plant, i.e., the stem, roots, tuber- bearing stolons and tubers (Figs. 155 and 156). The chief injury, of course, comes from the tuber infection, because it reduces the yield and renders the tubers more or less unmarketable for either table or seed stock. Infected tubers liave the appearance of being more or less covered with wart-like protrusions from the surface of the tuber. When freshly dug, the small, grayish-white ajipearing pustules of the disease are strikingly apparent (Fig. 156) ; but later on, as the surfaces of the tubers dry off and tlie epidermal covering of the common scab, except that the cup-like depressions of the powdery pustules becomes ruptured, it more nearly resembles those of the scab pustules are filled with brownish spores or spore masses. 282 POTATO DISEASES AND THEIR CONTROL Powdery scab also differs from tlie common scab in that the disease may continue to be active in storage ; whereas, the common scab is never active after the tubers are removed from tlie ground. It is chiefly disseminated through the planting of infected tubers. Other distribution agencies are spore-containing receptacles, such as second-hand sacks, barrels or baskets in which the crop is gath- ered ; and lastly, by means of transporting infected soil by the feet of farm animals, man, farm implements, etc. Preventive or Remedial Measures. — While it has not been definitely proven that the ordinary seed treatment recommended for common scab and rhizoctonia is an absolutely effective remedy for powdery scab, there is evidence that tends to indicate that such treatment does more or less completely inhibit* the disease. The principal methods of control are preventive rather than remedial. They consist in the selection and planting of clean seed, and in the practice of a definite crop rotation system. SPIXDLIXG SPROUT Description. — As yet, there is no direct evidence that the spind- ling sprout of the potato is caused by either a fungous or bacterial parasite. Tubers affected by spindling sprout produce numerous weak, needle-like sprouts, usually from most of the eyes, instead of a single, strong, vigorous shoot as in the case of normal seed stock. Pathologists and ph3^siologists are not agreed as to the cause of this phenomena. Various theories have been advanced, some of the more plausible being as follows: Spindling sprout may be the result of the tubers having developed during a hot, dry period and, being subjected to a high soil temperature, their vegetative vigor is seriously impaired. Exposure to high storage temperatures is also thought to be another cause. It Avould appear from these several theories that spindle sprout is simply an expression of impaired vegetative vigor, rather than the result of some causal organism. Preventive Measures. — Tbe only preventive measures neces- sary are the removal of all weak plants from the seed plot and the planting of strong healthy seed stock. XET NECROSIS Description. — Our knowledge of "net necrosis" is about on a par with that of spindling sprout. In fact, it is rather doubtful if the cause of this trouble is as well known as that of spindling OCCURRENCE AND DISTRIBUTION 283 sprout. It is thought that Jiet necrosis may be caused by unfavor- able growing conditions when the tubers are developing. Similar symptoms have been observed in tubers exposed to temperatures below the freezing point, in other words, that had been frosted. Tubers affected with net necrosis can only be detected by the removal of a thin slice from the stem-end of the tuber. The presence of radiating brownish or blackish lines is fairly good evi- dence that they are affected with this trouble. Preventive Measures. — All seed tubers showing discoloration of the flesh at the seed end should be discarded. Plant only healthy stock. CURLY-DWAKF Description. — This type of potato disease is in many respects quite similar in its appearance to that of the true leaf-roll. Orton^* (p. 38) describes its appearance as follows: "The stem and its branches, the leaf petioles, and even the mid-ribs and veins of the leaves all tend to be shortened, in many cases to a very marked extent, and particularly in the upper nodes of the plant, so that the foliage is thickly clustered. The diminished growth of the leaf veins, in proportion to the parenchyma, results in a bullate, wrinkled leaf, often strongly curled downward. There seems also to be a tendency to form more secondary branches than is normal, and, as these remain short and liave curly leaves, the compactness of the plants is more striking. The stems are also very brittle. The color of the foliage in curly-dwarf is typically a normal green, except that in very severe or advanced cases there is a lighter green or yellow color, sometimes accompanied by brown or reddish flecks in the leaves where the tissues are dying. Typical curly-dwarf is readily distinguished from leaf-roll by the wrinkled or downward curling of the leaves, the normal color of the foliage, and the firmness of the leaves which do not lack turgidity." As might be expected, the tuber yield from curly-dwarf plants is very much reduced from that of normal ones. The nature of the disease, like that of streak, has not been determined. It is thought by some pathologists to be simply an advanced stage of mosaic, but, as yet, there is not sufficient evidence at hand to fully confirm this supposition. Occurrence and Distribution. — Owing to the confusion now existing in the minds of many regarding the identity of mosaic- dwarf and curly-dwarf when they depart ever so slightly from the purely distinctive characters of one or the other, it is difficult to 284 POTATO DISEASES AND THEIR C^ONTROL express an opinion as to the general ])rcvalence of one or the other type of disease in a given locality. Orton is of the opinion {I.e. p. 39) "that curly-dwarf ])lays a large role in the deterioration of potatoes." The personal observations of the writer would incline him to believe that curly-dwarf is much more prevalent in the north- eastern portion of the United States. In fact, typical curly-dwarf plants are rarely noted in the western states. It has been more or less common among certain seedling potato strains in the Department's collection. Preventive Measures. — The same preventive measures should be pursued in the control of curly-dwarf as in that of leaf-roll and other related types of disease. Description. — Tip-burn is a purely physiological troul)le, due to the failure of the roothairs of the plant to furnish a sufficient supply of moisture to the leaves during dry, hot, windy and sun- shiny days, when the rate of moisture transpiration from the leaves is greater than the rate of supply. This causes a wilting and burning of the younger and more active cell tissues which are, of course, the extremities of the younger leaves. When this burning or, more strictly, scalding of the leaf tissue is sufficiently severe, the cell tissues are destroyed — the tip of the leaf drying up. If the heat and drought is sufficiently prolonged, the whole leaf may be destroyed. Control. — The surest method of preventing or minimizing tip- burn is by providing optimum conditions for the healthy and normal development of the potato plant. Land well supplied with organic matter, deeply plowed, thoroughly fitted and intelligently culti- vated, so as to induce deep rooting of the plants and conserve mois- ture, coupled with thorough spraying of the plants Avith Bordeaux mixture, furnishes the best insurance against injury from tip-burn. ARSENICAL INJURY Improperly used arsenical poisons frequently cause serious injury to the foliage of the potato. Arsenical injury is frequently confused with early, blight. Both produce l)rownish or blackened more or less irregular areas on the potato leaf, and also have more or less darkened concentric; rings in them (Fig. 157). PREVENTIVE MEASURES 285 # Fig. 157. — Arsenical injury of potato foliage; sometimes mistaken for early blight. (Maine Sta.) Preventive Measures. — Do not dust the plants with straight Paris green. If it seems desirable to use dry powdered Paris green, mix it witli at least 20 parts of land plaster, air-slaked lime or any other form of finely divided dry lime. Tf liquid applica- tions of Paris green are made, use at least two pounds of lime 286 POTATO DISEASES AND THEIR CONTROL to 50 gallons of the liquid. The lime neutralizes the free arsenious acid and thus prevents injury from burning. Other forms of arsenical poisons, which have white arsenic or arsenite of soda as their base, should be carefully tested for the presence of free arsenious acid; neutralize with lime if necessary. QUESTIONS ON THE TEXT 1. Name some of the principal fungous parasites of the potato. 2. What is the estimated loss in some seasons, from late blight alone in the United States? 3. Into what two groups or types of diseases are potato troubles classed? 4. What is meant by a parasitic disease? 5. What is meant by a non-parasitic disease? 6. What parts of the plant are attacked l)y early blight ? 7. How much injury does the potato plant sustain from early blight? Give various estimates cited. 8. What are the characteristic symptoms of early blight on the foliage? 9. What are the normal methods of infection? 10. How does the disease pass the Winter, and whence the source of new infections ? 11. How early does the disease make its first appearance on the early and the late crop? 12. What preventive measures may be employed? 13. How does the late blight differ from early blight? 14. Why is late blight more destructive than early blight? 15. In what portions of North America and Europe is late blight prevalent? 16. W^hat is the extent of its distribution? 17. Give a brief account of the life history of late blight. IS. What are the conidiospores? How are they borne? 19. How do the conidiospores infect the leaves of the potato? 20. How does tuber infection take place? 21. What control measure may be employed to lessen the prevalence of this disease? 22. What control measure can be employed to prevent infection? 23. Of what importance is a good sprayer and intelligent application of spray materials? 24. What kind of climatic conditions are favorable to late blight infection? 25. When should the first application of Bordeaux be made? 26. Describe the typical symptoms of fusarium wilt. 27. What species of fusarium is responsible for the fusarium wilt? 28. What are the two sources of infection? 29. What are some of the control measures that may be employed? 30. How may a large per cent, of fusarium-infected tubers be rejected when cutting them for planting? 31. How does the fusarium dry rot differ from fusarium wilt? What are the different forms of dry rot? 32. What is the nature of the injury caused by F. trichotheciodes? How widely prevalent is it? 33. How does verticillium wilt differ from fusarium wilt? Describe it. 34. What preventive measures can be used? 35. Of what economic importance is the disease known as rhizoctonia or black scurf? Give the nature of the loss. QUESTIONS ON THE TEXT 287 36. What are the chief distinguishing characters of plants infected with rhizoctonia ? 37. What preventive measures are suggested? 38. What is the cause of common scab? Wliat is the nature of its injury? 39. What remedial measures are recommended for its control? What preventive measures ? 40. What is the effect of turning under green manuring crops to correct soil alkalinitj'? 41. What are the distinguishing characteristics of silver scurf? 42. What is the best preventive measure? 43. When was the potato wart disease first recognized in North America' In United States? 44. Describe and give the life history of the wart disease. 45. What American varieties are immune to the disease? 46. What causes the leak disease of the potato? Describe it. 47. What are the most elfective preventive measures? 48. What causes tlie blackleg disease of the potato? Describe it. 49. What remedial and preventive measures are recommended? 50. What causes the soft rots of the potato? 51. Are the bacteria which cause soft rot parasitic or non-parasitic? Why do you .say so? 52. What control measures are suggested? 53. What organism causes the bacterial wilt of the potato? Describe the symptoms. 54. What preventive measures are suggested? 55. What is the cause of "streak"? How widespread? 56. Describe the general appearance of a streak infected plant. 57. What preventive measures are suggested? 58. When was the mosaic disease first observed in America? How general is it? * 59. Give symptoms and nature of the disease. CO. How is it transmitted? 01. To what extent does it affect yields? 62. What preventive measures are recommended? 63. What is the leaf-roll disease? Describe the symptoms. 64. What effect has it upon the yield? 65. What preventive measures are suggested? 66. When and where was powdery scab first observed in North America? In United States? Describe it. 67. What prevents its obtaining a foothold in the South? Give its climatic preferences. 68. What are the common distributive agencies of the disease? 69. What preventive or remedial measures are suggested? 70. What causes spindling sprout? 71. What effect has prolonged storage upon the germination of tubers and the size of sprouts? 72. What preventive or control measures are suggested? 73. What is known about net necrosis? Describe the diseased tubers. 74. What preventive measures are advocated ? 75. How does "curly-dwarf" differ from leaf-roll? Give symptoms and effect on yield. 76. Give distribution and preventive measures. 77. What causes tip-burn? Describe the injury, and give preventive measures. 78. Describe arsenical injury and tell how to avoid it. 288 POTATO DISEASES AND THEIR CONTROL QUESTIONS SUGGESTED BY THE TEXT 1. Name the potato diseases in order of their most frequent occurrence locally. 2. What proportion of the local growers tukc measures to prevent common scab? What measures? 3. What proportion of tlie local growers spray for late blight? 4. What pressure is used? How many nozzles to the row? 5. To what extent is dry rot injurious locally? 6. What local losses have been found due to soft rots? 7. What diseases seem to be increasing in local importance? 8. Collect specimens of as many potato diseases as possible. References Cited 1. C.\RPEXTER, C. W. Ifll5. Some potato tuber rots caused bv species of Fusarium. U. *S'. Dept. Agr. Jour. Agr. Res. 5: 180-209, Nov. I, 1915. 2. Cooxs, G. H. mi 4. Potato diseases of Michigan. Mich. ^ta. Spec. Bui. 66: 31, 1914. 3. Giissow, H. T. 1909. A serious potato disease occurring in New- foundland. Dom. Can. Cent. Exp. Farms Bui. 63: 1-8, Oct., 1909. 3a. 1913. Powdery scab of potatoes (Spongospora svhterranea (Walb) Johnson). Phytopath, 3: 18-19, 1 pi., 1 fig., 1913. 4. Hawkins, L. A. 1916. The disease of potatoes known as "leak." U. 8. Dept. Agr. Jour. Agr. Res. 6: 627-639, July 24. 1016. 1917. Experiments in the control of potato leak. U. H. Dept. Agr. Bui. 577: 1-5, Sept. 14, 1917. 5. Jack, R. W^. 1916. Potato spraying experiments for the control of Early Blight {Alfernaria solani). Rhodesia Aqr. Jour. 10: 8.^)2- 869, 1913; 13: 354-360. 1916. 6. Jones, L. R. 1912. Potato diseases in Wisconsin and their control. Wis. Sta. Circ. 36: 10, 1912. 6a. 1896. Various forms of potato blight, etc. Vt. Sta. Rpt. (1895) : 72-88, 1896. fib. 1906. The blackleg disease of the potato. Vt. Sta. Rpt. 1906: 257-265. 7. KuNKEL, L. 0. 1919. Wart of potatoes. (A disease now to the United States). TJ. S. Dept. Agr. Bm: Pit. Ind. C. T. and F. C. D. Circ. 6: 1-14, Feb. 6, 1919. 8. LuTMAN, B. F. ion. Twenty years spraying for potato diseases, etc. Tt. ma. Bvl. 159: 219, 1911. 9. Melhxis, I. E. 1915. Hibernation of Phytophthora infestans of the Irish potato. 77. 8. Dept. Agr. Jour. Agr. Res. 5: 72, 1915. 9a. '1913. The powdery scab of potatoes {Flpongospora solani) in Maine. Science, n.ser. 38: 1.33, 1913. 9b. 1914. Powdery scab {Spongospora suhterranea) of potatoes. U. S. Dept. Agr. Bui. 82: 1-16, April, 1914. 9c. , J. RosKxnAu^r and E. S. Schut.tz. 1916. Spongospora suhter- ranea and Phoma tuherosa on the Irish potato. TJ. 8. Dept. Agr. Jour. Agr. 7?p.s. 7: 214, 1916. 10. Merino, J. G. 1884 Mentioned by the Earl of Cathcart in an article on the cultivated potato. Joiir. Roy. Agr. 8oc. 20: 288-289, 1884. REFERENCES CITED 289 11. Mir.WARD, J. G. inOO. Dirc'ftioiis for spraying potatoes. Wis. Hta. Circ. Inform. 3, I'JOO. 12. Morse, W. J. l!Ji;i. I'owdrry scab of 2)otatue8 in llie Ignited .States. Science, ii. ser. 38: 61-62, 1913. 12a. 1909. Blackleg. (A bacterial disease of the Irish potato. Me. t^ta. Bui. 174: 309-328, Dec., 1909, 13. MuBPHY, P. A. 1917. The mosaic disease of potatoes. Agr. Oaz. Can. 4: 345-349, 1917. 14. Orton, W. a. 1914. Potato wilt, leaf-roll and related diseases. U. 8. Dept. Agr. Bui. 64: 7, Feb. 12, 1914. 14a. 1920. Streak disease of the potato. Phytoj)ath, 10: 97-100, pi. 8, Feb., 1920. 15. Pratt, 0. A. 1918. Soil fungi in relation to diseases of the Irish potato in southern Idaho. U. 8. Dept. Agr. Jour. Agr. Bes. 13: 75-77, 1918. 16. Rands, R. D. 1917. Earlv Blight of potatoes and related plants. Wis. Sta. Res. Bui. 42:\31, Aug., 1917. 17. SciiULTZ, E. S., D. FoLSOiM, F. M. HiLDEUJRANnT, and L. A. Hawkins, 1919. Investigations on mosaic disease of the Irish potato. U. 8. Dept. Agr. Joitr. Agr. Res. 17: 247-273, 8 pis., 1919. 18. Stewart, F. C. 1903. Potato spraying experiments in 1903. N. Y. (Geneva) Sta. Bui. 241: 252, Dec, 1903. 19. WORTLEY, E. J. 1915. The transmission of potato mosaic through the tuber. Science, n. ser. 42: 460-461, 1915. 19 CHAPTER XVI INSECT AND ANIMAL PARASITES OF THE POTATO AND METHODS OF CONTROLLING THEM The potato has numerous insect pests and at least one that is not a member of the insect famil)'. These combined enemies of the potato plant and tuber take an annual toll of many millions of dollars from the potato crop alone. A goodh^ portion of this loss is due to the failure of the grower to sufficiently protect his crop from the ravages of these pests. Unfortunately, however, a considerable portion of the injury is caused by insect or animal pests rather difficult of control, such as the flea beetle, aphid, leaf- hopper, tuber-moth and eelworm. These enemies of the potato naturally divide themselves into different groups, according to whether they have chewing or sucking organs, the parts of the plant they attack, and, in the case of the eelworm, their method of reproduction. Group classification of insect and animal parasites. A. Potato Insect Parasites /. Leaf-cheuing and mining inserts. 1. Colo, potato beetle Spray plants with arsenical poisons, such as 2. Flea beetle Paris <>reen, arsenate of lead, arsenite of 3. Three-lined beetle zinc, etc. 4. Tortoise beetle 5. Blister beetle 6. Tuber moth — see sec- tion II. //. Stem- and tuher-eating insects. 7. Stalk borer Crop rotation, and dostriu-tion of all infested 5. Stalk weevil plants. ^ „ . • f 9. Cutworm Poisoned bait; crop rotation; fall plowing ot 10. White grub land. 11. Wireworm , .,, , , r -i 6. Tuber moth Covering tubers with heavy layer of soil. Prompt harvesting of crop when ripe. Fumi- gation of storage house. Use of insect- free seed. 290 DESCRIPTION 291 ///. Sucking insects. 12. Potato aphid Spray with contact insecticides. 13. Four-lined leaf-bug 14. Leaf hopper Spray with contact insecticides and with Bor- deaux mixture as a repellent. Preventive and Remedial Measures. B. Potato Animal Parasites IV. Piercing and sticking. 15. Eel worm Crop rotation. Use of uninfested seed. COLORADO rOTATO BEETLE Occurrence and Distribution. — According to Britton,* the Colorado potato heetle, Leptinotarsa decemlineata, Say, was unknown to the potato growers of North America prior to 1855. About that period the frontier of potato growing reached the region where these beetles were native, and they developed such a liking for the foliage of the potato plant that they soon forsook the native solanums, on which they had been feeding, and became a serious pest of this crop. It is supposed that they crossed the Mississippi river about 1864 and reached the Atlantic seaboard states some ten 3-ears later. As there was then no practical equipment for spraying plants, the potato grower was obliged to hand-pick the bugs in order to prevent serious injury to the plants (Fig. 158). This laborious operation was soon displaced by the use of arsenical poisons, of which Paris green was the most commonly employed. At first, much of the spraying was done by hand, by the use of a whisk- broom or wisp of straw. This crude method was soon followed by the hand pump with spray nozzle attachment. The evolution of the spray puni]) has been rapid until, at the present time, there are many highly efficient mechanically, as well as gasoline, operated spray machines which do effective work (Fig. 159). Description. — The adult potato beetle is about three-eighths of an inch long and yellow in color, with five black stripes running lengthwise on each wing-cover and a series of black spots on the thorax. One female may lay from 500 to 1,000 eggs. The eggs are of a bright yellow color, about one-thirty-second of an inch in length. They are deposited in clusters on the under side of the leaves (Fig. 160) and hatch out in about a week. The larvae grow rapidly and, when nearing full size, consume a large amount 292 PARASITES Fig. 158. — The old and laborious nietliod of controlling the Colorado potato bcptle. Fig. l.J9. — The modern and less laborious nict hod of controlling the Colorado potato beetle. Courtesy Batenian Manufacturing Co. of foliage. The full grown larva is a Ptont, floshy grub, with a black head. and black s])ots over body (Fig. 1(51 ). They reach maturity in about three weeks, after which they enter the ground to pupate. Two to three generations arc produced in a season. DESCRIPTION AND LIFE HABITS 293 The last generation passes the Winter in the ground, emerging as a mature beetle early the next season. Remedial Measures. — Wliile the potato beetle is a serious enemy of the potato plant if left unmolested, it is, in reality, one of the most easily controlk'd. As it is a leaf-eating insect, the manifest thing to do is to keep the foliage of the plants well covered with some form of arsenical poison. Paris green, lead arsenate Fig. KiO.— Eggs of the Colorado bcetlp, twice the natural size. (Conn. Sta.) and zinc arsenite give xevy satisfactory results when used intelli- gently. Arsenical poisons may either be applied as dust or liquid sprays. While dust sprays may give very satisfactory results, the writer prefers to use liquid s])rays. The plants should l)e dusted or sprayed at about the time the first batch of eggs are hatching out, as they are much more easily poisoned when they are a few days old. THE POTATO FLEA BEETLE Description and Life Habits. — The potato flea beetle, Epitrix cucumeris, Harris, is a small, Idack, jumping beetle, slightly over one-sixteenth of an inch in length and about one twenty-fourth of an inch in width ; the antenna and legs are yellowish, but the body parts, including the head, wing covers and thorax, are jet black. 294 PARASITES The mature beetle eats small holes through the potato leaf, giving it the appearance of being artificially perforated (Fig. 162). When present in large numbers they cause very serious injury to the foliage and, as a result, very materially lessen the yield. The beetle lays its eggs under rubbish on the ground. The larvae have Fig. IGl.— Larvae of the Colorado potato beetle at work. (Conn. Sta.) slender thread-like bodies. They feed on the underground parts of the plant, particularly upon the tubers. I have personally observed dozens of larvas partially burrowed into the tuber. In some sections, the tubers are so seriously injured by the flea beetle larvffi as to be unsalable. The number of broods varies from one to two according to locality. It has been found that by delaying the date of planting, in some sections, it is possible to avoid a large portion of the injury caused by the first brood. REMEDIAL MEASURES 295 Remedial Measures. — Although arsenical poisons are quite generally recommended by the entomologist for the control of the flea beetle, the writer is yet to be convinced that poisons are an eflfective control measure. The flea beetles are difficult to control, as they usually work from the lower side of the leaf and do not always puncture clear through the leaf; therefore, poisons on the upper surface of the leaf are not likely to find their way into the Fig. 162. — Potato loaves severely injured by flea beetles. (Maine Sta.) digestive tracts of the flea beetle. The most hopeful measure of control is that of thoroughly covering the foliage with Bordeaux mixture. The Bordeaux covered foliage seems to be distasteful to the beetle, and in that way serves as a repellent rather than a remedy. A mechanical device for trapping the flea beetles was tested at the Ohio State University, some years ago, by Metcalf,^^ with apparent success. This device consisted of a soap box with cover, the front end removed, nearly half of the central part of the bottom and a good-sized notch in the lower side of the rear end cut away. The inside of the box was coated with tangle-foot, and when pushed forward along the row the flea beetles, jumping, 296 PARASITES when disturbed, were caught in the sticky material. By mounting this box on wheels and making some minor changes, it caught flea beetles at the rate of over 25,000 per acre. The use of this or some similar device suggests the possibility of exercising a fairly complete control of this insect pest. THREE-LINED POTATO BEETLE Description. — The three-lined potato beetle, Lcnut. inlineaia, Oliv., is yellow with three black stripes running lengthwise of its body (Fig. 163). It bears some resemblance to the striped cucumber beetle but is somewhat larger, with a constri('tcd thorax Fig. 163. — Three-lined potato beetle. Fig. 164. — Larvae feeding upon leaf, nat- Adulta on leaf , natural size. ural size. (Conn. Sta.) marked with two black dots. The eggs resemble in color those of the Colorado beetle, but are smaller and more apt to be deposited on the mid-rib of the leaf, instead of in clusters on the laminal portion. Tlie larvae diifer also from the Colorado beetle in their habit of feeding, as they usiuilly line up in a row on the under surface of the leaf and devour it as they move from tip to base of it, leaving the larger veins intact (Fig. 164). The larvae are buff or tan colored. There are two generations cacli year. Tlie winter i.s passed in the pupa stage. Remedial Measures. — The same measures are used to control this pest as are employed against the Colorado beetle. DESCRIPTION 297 TORTOISE BEETLES Description. — Tortoise beetles are only occasionally enemies of the potato plant. They are small hemispherical beetles, with a rather conspicuous marginal flange somewhat resembling the tor- toise in shape (Fig. 165). They usually feed upon the wild morn- ing glory and sweet potato, but are sometimes found upon the Fio. 165. — Adult Tortoise beetles on potato leaf, natural size. (Conn. Sta.) potato. Britton {I.e. p. 110) says there are at least three species ill Connecticut, viz., Coptocycla hicolor, C. clavata, and C. guttata. Bicolor is of a beautiful iridescent gold color, often with incon- spicuous black spots. It is sometimes called the "gold bug" or "gold beetle." Clavata and guttata both have brown backs with translucent marginal flange. The dark portion in guttata is more or less interspersed with translucent spots. Clavata is larger than guttata, and the brown area is quite rough. 298 PARASITES The eggs are laid singly on the veins or stems of the leaves; each egg is covered with a small mass of black excrement. The larvas are dull green, oval, with lateral projections or spines, and feed on the under surfaces of the leaf. Their excrement is carried on the caudal spines. Only one generation is produced each season. The adult beetles pass the winter in crevices, and appear on the potato plants during the month of May in Connecticut. The injury to the potato plants caused by these beetles is usually not a serious one. Remedial Measures. — They are readily controlled by arsenic poisons. BLISTER BEETLES Description. — Blister beetles only occasionally feed upon the potato plant. They are about half an inch long and about three- sixteenths of an inch in width, and have soft wing covers (Fig. 166). The principal species are the black blister beetle, Epicauta pennsylvanica, DeG. ; the margined blister beetle, E. marginata, Fabr. ; the striped blister beetle, E. vittata, Fabr.; and tlie ash gray blister beetle, Macrohasis unicolor, Kby. ; all of which occur in great numbers in certain seasons. The blister beetles fed upon potatoes long before the Colorado beetle and are sometimes called "old- fashioned potato beetles.^' They feed upon a variety of plants besides the potato, among which might be mentioned the golden rod and cultivated aster. The larvas do not feed upon potato foliage as do the adult beetles. Remedial Measures. — Being leaf-eating insects, they may be controlled by arsenical sj)rays. rOTATO 8TALK- AND STEM-BORERS The stalk- and steni-l)orers, like the blister beetles, do not confine their ravages to the potato plant alone; tomatoes, corn, rhubarb, sugar beets, dahlias, lilies and other plants furnish food for the larvae of these two insects. Life History and Habits. — The adult of the potato stalk-borer Papaipema nilela, Gn., is a purplish gray moth having a wing spread of about one and a quarter inches (Fig. 167). The eggs are deposited in the stem of the potato and the newly hatched larva LIFE HISTORY AND HABITS 299 begins tunnelling through the pith of the stem. The full grown larva is one and a half inches long. It passes througli the pupal stage in the tunnel made by the larva, and remains in the stem until it emerges as a moth the following spring. The life history of the potato stem-borer, Gortyna micacea, Est,, is somewhat different from that of the stalk-borer. According to _^ i'\G. 166. — Adult margined blister beetles feeding on potato leavee, natural size. (Conn. Sta.) Brittain^ : "The egg?> are laid by the female moth during the latter part of August and September. They are doubtless deposited on various weeds, thougli we have found them only on couch grass. They are very small, pinkish colored eggs, faintly ribbed, and are laid loosely sometimes in rather large numbers on the stem partially surrounded by the leaf sheath. The larvse hatch out in June and make their way to a suitable food plant, where they bore a tiny 300 PARASITES entrance hole in the stem, usually at the surface of the ground. They bore in the stem or in the crown of the plant until some time in August, and then enter the ground where they transform to pujxi', emerging in late x\ugust or September as adult moths." Occurrence. — The stalk-borer is not a serious pest, as it is seldom found in abundance in any locality. The distribution of the stem-borer is not given by Brittain, but it is evidently fairly com- mon in Nova Scotia. Preventive Measures. — As it is impossible to reach the larv« with arsenical poisons, the only control measures that can be employed are the destruction of the old potato stems and all weeds Fig. 167. — Adult Stalk-borer, natural size. (Conn. Sta.) known to be infested with the hibernating pupae, or that carry the eggs of the stem-borer. Eational crop rotation practices are also helpful. POTATO-STALK WEEVIL Occurrence. — The potato-stalk weevil, Trich ohoris irinotaia. Say, according to Fayville and Parrot,^'' was collected in Douglas County, Kansas, in 1873 by Professor Snow, and was first recorded by Popenoe.^^ He reported it as being common in eastern Kansas. It was particularly abundant in 1897, causing more or less serious injury to Kansas potato fields. Habits and Life History. — The potato-stalk weevil like that of the borer is not confined in ils food plants to the potato alone. REMEDIAL MEASURES 301 The horseiiettle, cocklebur, jiiuson weed and ground cherry are common host plants for this insect pest. The adult is a small snout-beetle, belonging to the same family of insects as the plum cuiculio. It is of an ashy-gray color, about one-fifth of an inch long and is marked with three black spots at the base of its vring covers. The female deposits her eggs in the stem, main, and secondary branches, by first cutting a slit about one-twelfth of an inch long in which she deposits one egg. The. same operation is repeated for each egg deposited. These eggs hatch in from seven to eleven days, and the small larva begins to work its way dowiiAvard towards the root of the stalk. After channelling down a distance, the larva turns round and works upward, enlarging the channel as it moves along. At maturity, the larva averages from three-eigliths to one-half of an inch in lengtli, with a brown head and dark-colored mouth parts. Tlie body Ijears a few light-colored hairs. Tlio ]-)U])al stage lasts from about eight to eleven days. The mature beetle remains in the stem until the following spring. Preventive Measures. — i'hnploy the same preventive measures as for the stalk-borer. As a rule, cutworms are not a serious pest of the potato. Where very abundant in the soil they may cut off a good many of the young stems, but rarely cause injury after the j)lant is six to eight inches higli. They usually cut the stem off near the surface of the ground. Life History. — Cutworms are the larvae of noctuid motlis and there are several species, three or four probably being responsible for most of the injury. There is but one generation each year, the moths emerging and the eggs being laid the latter part of the summer. The cutworms become partially grown before winter, after which they burrow deeply in the soil and remain there until spring. Their chief damage is done in tlie early spring, when the vegetable plants are young and tender. Remedial Measures. — As the cutworm is not a leaf eating insect and lives almost entirely in tlie ground, the usual methods employed to control leaf eaters are of no avail. The most effective 302 PARASITES remedial measure is to partially bury some poisoned bait. A poi- Boned and sweetened bran mash scattered over the soil or partially buried in it will destroy large numbers of them. The formula recommended by Britton {I.e. p. 112) is as follows: Wheat Bran 5 pounds Paris green or white arsenic 5 ounces Lemon or orange 1 fruit Molasses 1 pint Water 7 pints Mix the dry poison and bran together, then squeeze the juice from the lemon or orange into the water, cut the pulp and peel After Linville and into fine pieces and add them to the water, after which add the molasses and stir. Mix this syrup thoroughly with the poisoned bran. (Young clover stems may be substituted for the bran). Fall plowing the land is also a desirable practice. WHITE GRUBS Habits and Life History. — The natural food of the white grubs, Lachnosternn, like that of the cutworms and wireworms, con- sists largely of grass roots, but they also attack the underground parts of other plants, among which is the potato. The chief damage PREVENTIVE OR CONTROL MEASURES 303 to the potato by white grubs consists in their consumj^tion of por- tions of the tubers. When numerous enough, they may completely destroy the whole crop; such an occurrence is very rare, however, and only happens when the crop is planted on old sod land. White grubs are the larvaa of the May or June beetles (Fig. 168). The life cycle of the chief species requires three years for its completion. The female beetle deposits her eggs in the soil at a depth of from one to eight inches. The young grubs feed on decaying vege- u by wire worms. (Conn. Sta.) tation, but soon begin to eat the roots of living ])lants. They are most destructive to vegetation during the second year of their existence, but may also cause serious damage to early spring crops, the third year. Preventive or Control Measures. — One of the most effective control measures that can 1)e employed is that of crop rotation. Grubs are seldom present in land that is handled on a short rotation l)asi8, say three or four years, and may generally be expected in large numbers in old sod land, or in land that has been allowed to grow weeds for several years. Poisoned bait, such as recommended for cutworms, may be used on relatively small areas. All land sus- pected of being infested with white grubs should be plowed in the fall, in order to expose as many as possible of the white grubs to insect-devouring birds. 304 PARASITES WIKEWOKMS Life History and Habits. — Wireworiiis are ilio larvir of "dick'* vr "sua])" beetles, belonging to the family Elaterida}. They include several species which feed upon cultivated plants, most of which belong to three genera, Agriotes, Melanotus and Drasterius. These larva} are small, hard, cylindrical, and generally of a tan or reddish-brown color. It requires from three to five years for the wireworms to pass through their complete life cycle, all of which time, except their adult stage, is spent in the soil. While it is pos- sible that the wireworms may cause considerable damage to the Fig. 170. — Potato tuber moth greatly enlarged. (Bureau of Entomology.) roots and lower j)ortion of the stem of the potato plant, the injury is usually unnoticed. The chief observable injury is that caused by the wireworm boring into the seed tuber, often entirely destroying it and, in attacking the new tubers, making them unsalable and causing material waste in preparing those that are only slightly tunnelled (Fig. 169). Preventive or Control Measures. — The same control measures should l)e employed against the wireworms as those recommended for white grubs and cutworms. THE POTATO TUBER MOTH The potato tuber motli, Plithorima'a operculella, Zell., was first mentioned in literature by Captain H. Berthon- in 1855. Berthon stated that it had proved very damaging to potatoes in Tasmania in 1854. DESCRIPTION 305 Occurrence and Distribution. — It was first observed in the United States in 185(), liaving- l)een found in San Francisco, Cali- fornia. In 1873, Zeller-^ published the first technical description of the tuber moth which he made from * specimens collected in Texas. According to Graf^^ its distribution in the United States and foreign countries was as follows, in 1917 : California, Texas, Florida, North and South Carolina, and Virginia. The foreign \ '^- vZ^-2fc^ H Fig. 171. — Egg dusters of potato tubor moth deposited in and around potato eye. (Bureau of Entomology.) countries are Tasmania, New Zealand, Australia, Algeria, South Africa, India, Southern Europe, Italy, France, Spain, Canary Islands, Azores, and Hawaii. Origin. — While there is more or less controversy regarding the origin of the tuber moth, the bulk of the evidence would seem to justify the assumption that it is of American origin, probably from South America. Description. — The potato tuber moth is a small, gray, night- flying moth having a wing expanse of a little more than half an inch (Fig. 170.) It usually hides under clods or rubbish during the day time. The adult moth is comparatively short-lived. The 20 306 PARASITES male lives from 1 to 14 days and the female, 2 to 23 days. The female lays her eggs on the under side of the potato leaf, the petiole of the leaf or the stem of the plant. When potato tubers are ac- cessible, the eggs are also deposited on the tuber (Fig. 171). Gen- erally speaking, however, as long as the plants are green and thrifty, the female oviposits on leaf or stem rather than on tuber. The period of egg incubation varies from 5 to 34 days, depending on Fig. 172. — Injury caused by the tuber moth to the leaves and tips of shoots of the potato plant. (Bureau of Entomology. U. S. Dep't of Agriculture.) season of year and temperature. The newly hatched larvae seldom move about but commence at once to mine into leaf, stem or tuber, as the case may be. Those on the leaves eat through the epidermal structure and proceed to mine between the upper and lower epidermal layers of the leaf (Fig. 172). They may tunnel down the petiole into the stem of the leaf or may confine their min- ing operations entirely to the leaf blade. Larvae, hatched from eggs deposited in the eyes or cracks of tlie tuber, at once begin burrow- ing into the tuber (Figs. 173 and 174). The larvse feeding period ranges from 14 to 69 days. The longer period usually occurs in PREVENTIVE AND REMEDIAL MEASURES 307 the storage house at low temperatures. The period of pupation varies from 8 to 56 days (Fig. 175). Larvae feeding on the plant usually pass the pupal stage in curled or rolled up leaves, those in the stems partially protruding from old burrows, while others pupate under clods or rubbish. Amount o£ Injury. — The amount of injury caused to the potato crop by the tuber moth is directly dependent upon the prevalence of the insect and the way in which the crop is handled. As a rule, the injury caused to the plant itself is not serious, though Fig. 173. — Tuber injured by the larvse of the potato tuber moth Phthorimsea operculella. (Bureau of Entomology, U. S. Dept. of Agriculture.) under certain conditions, they might very materially reduce the yield. The chief injury ordinarily comes from tuber infestation. The larvse burrow through the flesh of the tuber, rendering it unsalable. When infested tubers are stored and not fumigated, heavy losses follow. Thus far, the potato tuber moth is only a seri- ous pest of the potato in California, In other localities in the United States, it has usually been associated with other plants, such as the tomato, eggplant and tobacco. Preventive and Remedial Measures. — The best preventive measures to emjDloy in combating the tuber moth are (1) soil 308 PARASITES sanitation; (2) crop rotation; (3) protection of tubers by ridging up soil over them; (4) the prompt harvesting of the crop as soon as it is ready to dig; (o) the gathering of the tubers as soon as possible after digging them. Soil sanitation consists in the re- moval and destruction of all unsalable potatoes as soon as the marketable crop is gathered. Crop rotation is always desirable. Fic. 174. — Section of a potato tuber showing larva and pupae of the potato tuber moth. (Bureau of Entomology, U.S. Dept. of Agriculture.) Tuber infection may be materially lessened by slightly ridging the soil over the tul)ers. This ])ractice prevents the female moths from reaching the tubers. The prompt harvesting of the crop before the vines are fully dead lessens the chances of tuber infestation, as the moth, ordinarily, prefers to lay eggs on the plant, rather than on the tubers; as soon, however, as the vines are dead, the eggs are laid on the tubers if they are within reach of the female moth. It is desirable to gather the tubers as quickly as possible after they POTATO APHIDS 309 are dug, because the disturljed moths fly about even during davlight, and oviposit on the newly harvested tubers. If the tubers are known to be infested by larvae or to carry eggs, they should be fumigated as soon after putting them in tlie storage house as possible, POTATO APHIDS There are at least two distinct kinds of aphids or plant lice that cause more or less injury to the potato crop. These two aphids are known scientifically as Mucrosiphum solanifolii, Ashm.; and I Fig. 175. — Larvae and pupa of the potato tuber of Entomology, U.S. Dept. of Agriculture.) loth greatly enlarged. (Bureau Myzus (Rhopalosiphum.) persica', Sulzer. The first is commonly known as the pink and green plant louse, on account of portions of some broods being pink and others green. The second is known as the green peach or spinach aphid. These plant lice belong to the 310 PARASITES class known as sucking insects; that is, tliej- live upon the juices of their host plant, which they suck from it b}^ inserting tlieir beaks into its tissues. In 1917 and 1918, potato aphids were quite gener- ally prevalent throughout the whole northeastern potato-growing section of the United States, causing an untold amount of damage to the crop. In some localities they were so abundant thiit they actually sucked out so much of the juices of the potato plant as to cause a premature ripening with a consequent material lessening of the crop yield. In 1919 and 1920, they were not so abundant and little damage resulted. In 1907, Dr. Edith M. Patch^'^ reported a serious outbreak of plant lice on potatoes in Aroostook County, Maine, during the seasons of 1904, 1905 and 1906. Apparently, therefore, these periodic recurrences of the potato aphid are the result of the rise and fall of its parasitic enemies of which it has a numl)er. The rather recent discovery that the mosaic disease of the potato is transmitted from diseased to healthy plants, througli tlie agency of these two plant lice, serves to still further emphasize the neces- sity of controlling or combating these insect pests by every known practical method. Life History of These Two Plant Lice. — The pink and green plaiit louse over-winters in the egg stage. In the Spring, the egg hatches and produces what is known as the "stem mother." This insect, in from 10 to 12 days' time, begins to produce living young, all of which are gravid females and capal)le of producing new batches of similar living young in about the same period of time as the "stem mother." The rapidity of this process of multipli- cation is best understood from some observations made at the Ohio Station, in which a single aphid of this species was caged on an uninfested plant. At the end of 12 days, her progeny (daughters and grand-daughters) totalled 76, five of which were already pro- ducing young. It requires little imagination to picture tlie rapidity of the increase from this point on. Most of the broods produced during the season are wingless (Figs. 176 and 177), but there are occasional winged broods. The winged broods migrate much more rapidly than tlie wingless ones, and they are generally referred to as the migrant forms. Toward the close of the season, a brood of males and females is produced. After mating, the female lays a few rather large eggs, usually on rose 1)ushes, if they grow in the locality, and thus they complete their life cycle. LIFE HISTORY OF POTATO APHIDS 311 The green peach or spinach aphids usually over-winter in the egg stage. In a mild climate, where succulent vegetables such as spinach, cabbage or kale continue growth throughout the winter, there is a constant succession of broods. As a rule, however, the Fig. 176. — ^Potato aphids on under side of the leaves, natural size. (Conn. Sta.) winged broods of aphids migrate to the peach or plum tree during the autumn and there the females deposit their eggs. In the spring these eggs hatch out, and from thence on the method of reproduction is similar to that of the pink and green louse, except that the first few generations live on the juices of the peach or plum tree, after 312 PARASITES which they migrate to a large number of other plants, of which spinach and the potato are good examples. Remedial Measures. — As plant lice are sucking insects it is necessary to employ contact insecticides to destroy them. liack of ■ success in the con- trol of the plant louse is largely due to failure to spray sufficiently early in .sJ|L WK^B IJjMmL.^ ^^^ season. In fact, ^l^f^^^ PUSi J^^^Sl ^^ ^'^^^ roses or cul- tivated ones occur in the locality, the first step in the con- trol of the pink or green louse is to destroy these plants and the peach and plum trees before the eggs hatch; or else thoroughly spray them, while still dormant, with a lime sulphur solu- tion to destroy the eggs; or a later spraying, when the "stem mother" first hatches out, with a nicotine or kerosene emulsion solution. The destruction of the early broods is the key to their con- trol. If these earlier precautions are not taken, a careful watch should be kept of the plants for the first appearance of the aphids in order to insure spraying, before they become so numerous, and so well ensconced on the under side of the leaves as to make it difficult to reach them with spraying materials. A proprietary nicotine sulphate compound, Fia. 177. — Potato aphids on the tip of A favorite feeding ground. (Maine Sta.) growing shoot. REMEDIAL MEASURES 313 .. V ■.•.,«» 314 PARASITES known as black-leaf No. 40, is generally considered one of the most convenient and effective contact insecticides. A well made kerosene emulsion solution is regarded by some as more effective, provided it is well applied. Failure to get good results from the sprays is very often due to the inefficient application of them. A good power sprayer carrying a pressure of from 175 to 250 pounds per square inch and two or three nozzles to the row, so adjusted as to spray the under as well as the upper side of the foliage, is necessary to effectively control the aphids. It is desirable, when the plants are large and the foliage heavy, to attach a device, in the shape of a drop rod, to the rear of the spray machine, but in front of the spray boom for the purpose of bending over the tops of the plants, thus making it possible to spray the under side of tlie foliage. By slipping a larger rod over the rigid one of sufficient size so that it will roll on it, the injury to the foliage caused by brushing the plants over will be very materially minimized. Direc- tions for the use of spray materials -svill be found in Chapter XVII. THE FOUK-LINED LEAF-BUG Life History. — The four-lined leaf-bug, Poecilocapsus lineatus, Fabr., is only an occasional pest of the potato plant. According to Britton,* it lays its eggs on the soft tender stems of the currant, and doubtless other plants, about the first of July, in Connecticut. The eggs are long and slender, somewhat curved, and are crowded together in clusters of six or eight, pushed endwise into the soft pith. These eggs do not hatch out until the following May. The newly hatched insects first attack the tips of the stems and the young tender leaves. They suck out the green pulp from the under side of the leaves, causing roundish, semi-transparent spots which often coalesce (Fig. 178). As insects increase in size, larger areas are involved, until the leaf turns brown, and dies. The nymphs at first are bright-red, marked with black spots, but they soon change to bright orange-yellow. They pass through five stages of development in al)Out three weeks and wlien mature, are winged, nearly one-third of an inch in length, bright greenish-yellow in color with four black stripes running lengthwise on thorax and wing covers (Fig. 178). Remedial Measures. — Spray plants with same materials as were recommended for the potato aphids. LIFE HISTORY OF LEAFHOPPER 315 THE POTATO LEAFHOPPER Occurrence and Injury Caused. — While the potato leafhopper Einpoasca iiiali was originally described by Le Baron in 1853 as injurious to fruit trees in Illinois, it has since been found that it also feeds on many other field and truck crops. In 1896, Osburn^" mentioned it as being injurious to potatoes in Iowa. Twelve years later, Gibson^ ^ records similar observations regarding its injuriousness to the potato crop at Ottawa. BalP (1918) was the first observer to call attention to the possibility of the leafhopper being responsible for some of the injury heretofore called "tip- burn." He, in fact, is inclined to the opinion that this insect causes a specific infection similar in many respects to that transmitted to the leaves of beets by the beet leafhopper. Ball has classified the foliage injury caused by the leafhopper as "hopperburn," in contradistinction to the term "tip-burn" under which all burning of the foliage, outside of that caused by arsenical poisons, has here- tofore been known. In this connection he says (1919, p. 150) : "It seems probable that a considerable amount of the injury re- ferred to as 'tip-burn,' in the past, has been due to the leafhopper. On the other hand, there are, no doubt, other causes of the burning of the foliage, and it will be one of the problems of the future to differentiate these factors." Description. — The adult leafhopper is a pale green insect about one-eighth of an inch long with wings that fold over the back. The nymphs, or immature forms, are wingless (Fig. 179). Both are very active and jump or fly away on the slightest distur- bance. The adults are, of course, the more active on account of their being able to fly. Life History. — The leafhoppers pass the winter in the adult stage hidden beneath weeds and other rubbish, and appear in the spring when they deposit their eggs. BalP says (1919, p. 153) : "The adults flying in the spring at the time the early potatoes come up, laid their eggs in the stems and mid-ribs of the leaves." Euggles and Graham,^'* X)n the other hand, say that they do not usually make their appearance on the potatoes until late June, when the adults lay eggs on the stems. This may be true with respect to the late potato crop, but it can hardly apply to the early crop, as their date of appearance must be considerably earlier. The eggs are deposited in a longitudinal or transverse slit in the tender tips of 316 PARASITES the shoots or the mid-ribs of the leaves. They soon hatch out, and the wingless nymphs begin at once to suck the juices of the plants and reach maturity in about a month. During this period the nymphs cast their skins five times. They usually feed on the under side of the leaf where it is difficult to reach them ^nth contact insecticides (Fig. 179). Two broods of leaf hoppers are produced during the season; the first one appears in June, and tlie second one about August 1. Description of the Injury. — BalP (1918 p. 98) descril)es the injury as follows : "The first appearance of injury differs slightly Fig. 179. — Leaf hoppers (Empoasca mali) on potato leaf. (Dr. E. D. Ball, Iowa Sta.) in the different varieties and varies also with the number of insects and whether they are in the nymph or adult stage. In certain varieties, the leaves appear to curl uj) slightly before any burning appears The first sign of trouble is usually a triangular area at the tip of the leaf, running back on tlie mid-rib. This is quickly followed by a progressive burning of the margin, usually from the ti]) backwards, but occasionally in more or less triangular spots appearing along the margin, each one of these centred in a lateral veinlet. Tliese increase in area and the burnt margin increases in width until nothing but a narrow strip along the mid-rib remains green and, in serious cases, this weakens and dies and tlie leaf shrivels up. "In practically all cases, it will be ol)served that the burning extends farther along the mid-rib and the lateral veinlets than it AMOUNT OF INJURY 317 does on the membrane of the leaf. A further examination will show that these veins and veinlets are badly distorted by punctures and usually shrivelled and collapsed for some distance back of an apparent injury. In many cases, it will be found that an egg deposited transversely across the mid-rib just back of the triangular spot at the tip was res})onsible for the collaj)se of this structure \t.. \ ) Figs. 180 and 181. — Tubers infested with eelworms. and the consequent death of the triangle at the tip." Ball {I.e. p. 79) draws the following distinctions between tip-burn and hopi^erburn : "On leaves of different plants, where no insect agency was apparently present it was observed that the burning appeared to affect the membrane of the leaves and to avoid the mid-rib and veinlets; while hopperburn appeared first on the vein- lets, and spread later to the area of membrane which they supplied." Amount of Injury. — While it is very difficult to estimate the amount of injury to the potato crop, as a result of leafhopper attacks, it is safe to say that when these insects are abundant they 318 PARASITES very materially lessen the yield. In some fields of both early and late potatoes, observed by the writer in 1919, the indications were that the yield had been reduced fully 50 per cent. Remedial and Preventive Measures. — As the leafbopper is a sucking insect, the same remedies should be used in combating it as those suggested for the pink and green aphids, viz., nicotine sulfate or kerosene emulsion, and the same thoroughness of application is necessary to get even fair results. The leafhopper being such an active insect, hopping or Hying away on the slightest Fig. 182. — Tubers badly infested with eelworms. disturbance, is more difficult to destroy than is the potato aphid. The best preventive measure is secured through keeping the plants well covered with Bordeaux mixture. The mixture serves as a repellent to the insect by rendering the foliage distasteful to it. THE EELWORM DISEASE Among the many parasites of the potato the eelworm or nema- tode, Heterodem radicioln, is one of the most interesting. It is an animal parasite which lives upon the juices of the host plant infested. It attacks many members of the vegetable king- dom, among which is included the potato. Thus far, it has caused greater injury to the potato crop in certain portions of California, Nevada, Texas, Florida, and the South Atlantic States as far North as Virginia, than in other localities. It has a rather wide distribution in the warmer portions and lighter soils of the South. LIFE HISTORY OF THE EELWORM 319 Description of the Injury. — The presence of eelworms in the potato crop may be detected from the general appearance of the roots and tubers of the plant. Eoots that have been invaded by the eelworni are almost certain to have well-developed knots or enlargements, and the surface of the tubers will be more or less dis- figured by pimply or wart-like developments, (Figs. 180 to 182), depending upon the severity of the attack. It is quite possible to mistake these pimply growths for those caused by the larvee of the Fig. 183. — Photographs taken through the microscope of three stages in the develop- ment of the eelworm which affects the potato. (A) An egg which contains a young coiled eelworm or larva enlarged 185 times. (B) A larva at the same magnification. It is in this stage that the eelworms penetrate the roots and tubers of the plants. (C) A matured, pear- shaped female enlarged about 25 times. flea beetle. The only way by which the two can be certainly identified is by an examination of the tissue of these growths; if they are caused by the eelworm, the white, glistening, pear-shaped bodies of the mature female will be noted; (Fig. 183 c) whereas, if caused by flea beetle larvte, only dead vegetable tissue will be observed. Life History of the Eelworm. — According to Byars,^ "there are three readily recognizable stages in the life histoi*y of this eelworm, or as it is more commonly known, nematode; namely. 320 PARASITES the egg, larvae, and adult (Fig. 183). Only tlie adults are visil)le to the naked eye." The newly hatched hirva3 escape into the soil, seek the underground portions of the plant stem, roots or tubers, penetrate them and once within, develop into tlie adult stage. After the mating of the males and females, the former soon die. The females remain in the host tissue, and are capable of laying large numbers of eggs which, in turn, give rise to another generation of larvffi, thus completing the life cycle. Preventive Measures. — Serious injury to the potato crop may be largely avoided through the observance of certain precautionary measures. In the first place, eelworm-infested tubers sliould never be used for seed purposes; use only clean seed. Practise at least a three- or four-year rotation on land knowai to be infested with eelworm. Use rotation crops that are resistant to them, such as velvet beans, beggar weed, and certain resistant strains of cowpeas.* By such practice, the eelworm may be largely exterminated through .starvation. Clean cultivation of these crops is necessary to the successful starving out of the eelworm, as the weeds, if permitted to grow, might serve as host plants for this pest. QUESTIONS ON THE TEXT 1. To what extent do these pests injure the potato crop? 2. Into what two general groups may these pests be divided? ^. Name the four classes into which the two groups are divided? 4. To what group does the Colorado beetle belong? 5. Give a brief history of the eastward march of the potato beetle? 6. What is its life history? 7. How is it controlled? 8. Describe the potato flea beetle and tell of its injury. !). How can the Ilea beetle be controlled? 10. Describe the three-lined potato beetle. Give its life history. 11. What remedial measures are advocated? 12. Describe the tortoise beetles and give distinguishing characters of three species. 13. Wliat is their life history? How are they best controlled? 14. Describe the blister beetles and their injury. 15. How are they best controlled? 16. Describe the stalk-borer and its work. 17. Give its life history and control. 18. Describe the potato stalk-weevil. 19. Give its life history and control 20. How do cutworms injure the potato? How many species attack it? 21. Give their life history and control. 22. What is the natural food of the white grub? * For a larger list of immune or resistant crop plants see: — U. S. Dept. Agr. Farmers' Bulletin, 648. REFERENCES CITED 321 23. Upon what parts of the potato plant does it feed? 24. Give life histoiy and control. 25. Describe the wireworms and their work. 26. Give the life history and control. 27. By whom and at what date was the potato tuber moth first mentioned in literature? 28. Give its origin and distribution. 29. Describe the potato tuber moth and its injury. ;10. Give its life history and control. 31. How would you deal with insect infested tubers in storage? 32. Give a common name of potato aphids. What kind of mouth parts? 33. Give its life history and control. 34. Describe the application of insecticide to the lower surface of the leaves. 35. Describe the four-lined leaf-bug and its work. 36. What remedial measures are recommended? 37. When was the apple leafhopper first regarded as a potato pest? 38. Describe it and its work. 39. What is its life history and control? 40. How may one detect the presence of the eelworm in the potato crop? 41. Give the life history of the eelworm. 42. What preventive measures can be employed? QUESTIONS AND EXERCISES SUGGESTED BY THE TEXT 1. Name the five leading insect or animal enemies of the potato in order of their local importance. 2. Collect specimens of such insects. 3. Collect samples of injuries from such enemies. 4. What methods of control are used by local growers against the worst enemies ? 5. Calculate the annual cost of such control measures on one or more farms. 6. Calculate the saving by same. References Cited 1. Ball, E. D. 1918. The potato leafhopper and the hopperburn that it causes. Wis. l^tate Dent. Agr. Bid. 20, Dec. 31, 1918, p. 76-102, pi. 6. 1919. The potato leafhopper and its relation to hopperburn. Jour. Econ. Ent. V. 12, No. 2, April, 1919, p. 149-155, pi. 5, fig. 1. 1919. The potato leafhopper and the hopperburn. In Phytopath, V. 9, No. 7, July, 1919, p. 291-293. 2. Berthon, H. 1855. On the potato moth. In Papers and Proc. Roy. Soc. Tan Deman's Land. Vol. 3, pt. 1, p. 76-80. 3. Brittaix, W. N. 1917. Two Important Vegetable Pests. Nova Scotia Coll. Agr. Circ. 26: 1. 4. Britton, W. E. 1918. Insects attacking the potato crop in Connecticut. Conn. Agr. Exp. Sta. But. 208, Oct., 1918, p. 103-119, illus. 5. Byars, L. p. 1919. Eelworm disease of the potato. Potato Mag. V. 1, No. 12, June, 1919, p. 10. 6. Chittenden, F. H. 1913. The potato tuber moth. U. 8. Dept. Agr. Farmers' Bui. 557, Oct., 1913, 7 p., illus. 21 322 PARASITES 1917. How to increase the potato crop by spraying. U. 8. Dept. Agr. Farmers' Bui. 868, Sept., 1917, 22 p. illus.' 7. Clarke, Warren T. 1901. The potato-worm in California. Calif. Agr. Exp. Sta. Bui. 135, Oct., 1901, 30 p., illus. 8. DoTEN, S. B. 1911. The potato eelworm. Nev. Agr. Exp. Bfa. Bui. 76, March, 1911, 7 p., illus. 9. EssiG, E. O. 1913. The potato tuber moth. In Mo. Bui. Calif. Hort. Com., V. 2, No. 9, p. 665-666, fig. 365. 10. Fayville, E. E. and Parrott, P. J. 1899. The potato stalk-weevil. Kan. Agr. Exp. 8ta. Bui. 82, Jan., 1899, 12 p., illus. 11. Gibson, A. 1909. Insects for the year 1908 at Ottawa. In SOth Ann. Rpt. Ont. Ent. Soc, p. 116-120. 12. Graf, J. E. 1917. The potato tuber moth. U. S. Dept. Agr. Bui. 427, Feb., 1917, 56 p., illus. 13. HousER, J. S., GuYTON, F. L., and LowRY, P. R. 1917. The pink and green aphid of the potato. Ohio Agr. Exp. Sta. Bui. 317, p. 61-88, illus. 14. Le Baron, W. 1853. Observations upon two species of insects injuri- ous to fruit trees. In Prairie Farmer, Sept., 1853, p. 330-331. 15. Metcalf, C. L. 1915. A mechanical measure for controlling Ilea beetle (Epitrix fuscula). Jour. Econ. Ent. 8: 240-241, illus. 1915. 16. OsBORN, H. 1896. A new pest of potatoes. Iowa Agr. Exp. 8ta. Bui. 33, p. 603-605. 17. Patch, Edith M. 1907. The potato plant louse. Maine. Agr. Exp. Sta. Bui. 147, Nov., 1907, p. 235-257, illus. ^1919. Spray pink and green potato aphids. Potato Mag. V. 1, No. 12, June, 1919, p. 8, illus. 18. PoPENOE, E. A. 1877. A 'list of Kansas Coleoptera. Trans. Kan. Acad. 8ci. (1876) 6: 39, 1877. 19. RuGGLES, A. G., and Graham, S. A. 1919. Potato insects. In Minn. Farmers' Inst. Ann., No. 3, p. 96. 20. ScoFiELD, C. S. 1912. The nematode gallworm on potatoes and other crop plants in Nevada. U. S. Dept. Agr., Bur. Pit. Indus. Circ. 91, Feb., 1912, 15 p., illus. 21. Zelleu, p. C. 1873. Beitrage zur Kenntnis der Nordamericanischer Nachf alter, besonders der Microlepidopteren. Alt. 2, p. 63. CHAPTER XVII FUNGICIDES AND INSECTICIDES: THEIR PREPARA- TION, USE, APPLICATION, AND RESULTANT BENEFITS. SPRAY EQUIPMENT AND CLASSIFICATION General Discussion. — In previous chapters it has been clearly shown that maximum potato crops are dependent, in no small measure, upon the degree of protection given the plants against the attack of fungous or insect pests through fungicidal or insecti- cidal applications. In the present chapter it is proposed to give a list of the more commonly used fungicides and insecticides for the control of disease or insect enemies of the potato plant and tuber. It has been shown, in the chapter on diseases, that certain fungous pests attack both plant and tuber ; that others attack only the foli- age, or only the tuber; that some are controlled by spraying the plants, and others by treating the seed. In the case of insect pests, it has been noted that some are controlled by poisons; others by contact insecticides; some by poisonous gases; and still others by wdiat we call repellents; as, for example, the presence of a good coating of Bordeaux mixture over the surface of the leaves of a potato plant serves as a more or less effective repellent against the attacks of the flea beetle and the potato leafhopper. Group Classification of Fungicides and Insecticides. — For the sake of convenience in discussion, the fungicides and insecticides have been grouped according to their uses. Fungicides controUin g Foliage diseases Tuber diseases Bordeaux mixture Bordeaux paste Dry Bordeaux Pyrox Corrosive sublimate Formalin solution 323 324 FUNGICIDES AND INSECTICIDES Insecticides controlling Leaf-fhewinj' insects Sucking insects Paris green Arsenate of lead Calcium arsenate Arsenoids Arsenite of zinc Pyrox Bug-death I Nicotine sulphate •{ Kerosene emulsion Whale-oil soap Tuber-eating insects J c'arbon bisulphide Thus, Ave have fungicides controlling foliage diseases, and those that control certain diseases affecting the tubers. In a similar manner, there are insecticides that control leal'-eating insects; others that control sucking insects, etc. Fungicides Controlling Foliage Diseases. — in the discussion of the fungicides controlling foliage diseases, it is proposed to devote the major portion of it to Bordeaux mixture, because it is believed to be the most important fungicide yet available for the control of the early and late blight. Bordeaux Mixture. — The history of the origin of this fungicide is ratlier interesting in tliat it may be regarded as of accidental occurrence. The discovery that milk of lime, to which a cop})er salt had been added, possessed fungicidal ]iro])erties was tlie result of an attempt on the part of certain viiieyardists in the vicinity of Margaux, St. Julian, and Pauillac, France, to deter travellers in that region from molesting the fruit in the vineyards bordering the public highways. The salt of copper was added to the lime to give it the appearance of a poisonous compound. It was noted in 1882, during a severe epidemic of the downy mildew of the grape, that the foliage of the vines to which the above mixture had been applied remained green and healtby, while the leaves on adjacent vines not sprayed, or those that liad received an application of PREPARATION OF BORDEAUX MIXTURE 325 milk of lime alone, were destroyed by the mildew. In 1885 Millardet," as a result of experimental studies, published an article in which he gave the following directions for preparing the mix- ture, which was then known under the name of "bouillie bordelaise." "In 100 litres of water (26.42 gallons) dissolve 8 kilos (17.6 pounds) of commercial sulfate of copper. In 30 litres of water (7.93 gallons) slake 15 kilos (33.1 pounds) of quicklime. Add the milk of lime to the copper sulfate solution and stir it well." This mixture, in the absence of spray equipment such as we now have, was applied to the foliage by means of a small whisk broom. Such was the origin of the fungicide now so widely known as Bordeaux mixture. The name it now bears must have soon re- ])laced that of "bouillie bordelaise," as it was known in this country as Bordeaux mixture in 1889. The formula in general use in 1889 and 1890 called for (> pounds of copper sulfate and 4 of quicklime to 22 gallons of water. Bordeaux mixture of this com- position was made by the writer and applied to potato plants with a watering can in 1890. A single application of this mixture, in the latter part of the growing season, was sufficient to thoroughly ])rotect potato foliage against a severe epidemic of late blight, which completely destroyed unsprayed plants. The present standard Bordeaux mixture formula for potatoes is known as the 5-5-50 ; that is, 5 pounds copper sulphate, 5 pounds lime and 50 gallons of water. In regions where late blight is of infrequent occurrence, or in seasons when the climatic conditions are unfavorable to its development, a 4-4-50 Bordeaux will give satisfactory results. In fact, some pathologists now favor the weaker mixture, but it is believed that material of this strength will not so elTectively control late blight as will the 5-5-50 formula. Preparation of Bordeaux Mixture. — Although the preparation of Bordeaux mixture is comparatively simple, it is surprising how often it is improperly made; this, too, in spite of the fact that practically every Experiment Station and farm paper in the country has published detailed instructions as to how it should be made. The reason for this failure to observe the prescribed rules is, we believe, due to a lack of appreciation of the fact that good, bad and indifferent Bordeaux mixture can be manufactured from the same ingredients. A thorough understanding of what constitutes good Bordeaux mixture, and Avhat details are necessary to observe in order to secure it, is the first essential to success. A good Bordeaux 326 FUNGICIDES AND INSECTICIDES mixture is oue in which the precipitate formed by the copper salt and the lime is in a very finely divided or flocculent condition. The question may be asked : What has the fineness of the precipi- tate got to do with the quality of the Bordeaux mixture? The answer is that the more finely divided the particles constituting the precipitate, the longer will they remain in suspension in the liquid, and the more evenly and more completely will they cover the foliage of the potato plant. A bad Bordeaux mixture is one in which the precipitate is in the form of coarse particles which quickly settle to the bottom of the spray tank, unless the material is kept in a constant state of agitation, and which has a tendency to clog the nozzles and to spread unevenly over the surface of the leaves. Three Steps in Making Bordeaux. — The next proljlem con- fronting us is, how to make good Bordeaux mixture. Practically all directions that have been published concerning the making of Bordeaux mixture, if adhered to closely, will insure a good Bordeaux mixture. Let us see what the successive steps are in the manu- facture of Bordeaux mixture. (1) In the first place, we are instructed to weigh out 5 pounds of copper sulphate, if a 50-gallon spray tank is to be used, or 10 pounds if a 100-gallon spray tank is available. The crystalline copper sulphate, or blue vitriol as it is often called, is to be dissolved in water, say 20 gallons, in a wooden vessel; an earthen vessel may be used, but never a metal one as the copper corrodes the metal. The crystals may be more quickly brought into solution by using a small volume of hot water, or by enclosing them in a coarse sack or piece of cheesecloth and suspending them in the upper surface of the water. (2) Weigh out an equal quantity of quicklime or slightly more of the hy- drated lime, and slake it in a separate vessel, using just enough water to make a thick paste when slaked ; then add sufficient water to make 20 gallons. (3) The copper sulphate solution and the milk of lime should then be simultaneously poured together in a third vessel, thoroughly stirred and made up to volume (Fig. 184), in this case to 50 gallons. The fineness of the i)recipitate is directly dependent upon diluting the two ingredients, then pouring them together at about the same rate into a third vessel and thoroughly stirring the mixture. Bad Bordeaux mixture or one in which the precipitate is in the form of coarse particles, is the direct result of pouring the BAD BORDEAUX MIXTURE 321 two ingredients together in a concentrated form, or by pouring the one into the otlier without proper dihition. The worst mixture seems to result from pouring the undiluted copper solution into the milk of lime. Many grOM-ers make a practice of putting the concentrated copper solution into the spray tank and then adding the milk of lime to it, after which they add the necessary water to bring it up to the required volume. This is a bad practice and should be unequivocally condemned. Practically all improperly Fig. 184.— Bord and then pouring the two together as show eaux mixture is made by making the two suock solutions separately n. (U. • - " (U. S. Dept. of Agriculture.) made Bordeaux mixture is the result of an attempt on the part of the grower to economize on equipment, as, for example, a few 50-gallon barrels. It is believed that, even from the labor-saving standpoint, this is a false economy; and there certainly can be no question about the wisdom of such a procedure when it results in the manufacture of inferior mixture. The object of introducing the above discussion is not for the purpose of decrying labor-saving methods, or the desirability of eliminating all unnecessary equip- ment, but rather to remind those who are disposed to adopt shortcuts that there is such a thing as a wasteful economy, a saving of pennies at the expense of dollars, which results in loss rather than in gain. The operator should believe fully in the adoption 328 FUNGICIDES AND INSECTICIDE8 of all nietliods that make for the elimination of waste effort, and which, at the same time, j^roduces a high grade Bordeaux mixture. System in the Work. — One of the most efficient labor-saving devices in the manufacture of Bordeaux mixture is that of the spray mixing platform, and the stock solution barrels. The fol- lowing description is one which the writer prepared for the Seventeenth Annual Report of Hie Vermont Agriciilfiinil Experi- ment Station for the years 1903-04, p. 440-442: Fig. 185. — Spray mixing platform at the Vermont Experiment Station showins opera- tion of filling spray barrel. Barrels in rear of upper platform contain tlie stock solutions, those iu the front are the dilution barrels while the one with the strainer is the mixing barrel. "The horticultural department has devoted considerable attention, dur- ing the past two seasons, to simplifying the labor of making Bordeaux mixture. Two objects were in view : ( 1 ) To avoid lifting, so far as practicable. (2) To promote the formation of a fine precipitate, and, there- fore, of a perfect mixture. "A Gravity System. — To obviate the necessity of lifting the mixture, when lining the spray pump barrel, a lean-to shed was used to serve the purpose of a temporary support to a two-tier stage or platform. (Fig. 185). On the upper platform were disposed the 1)arrels, which were intended for stock solutions of lime and copper sulfate, and. also, those in which these solutions were to be diluted, preparatory to mixing in the third vessel on the platform below. These dilution vessels were provided with good sized faucets which were brought sufficiently close together to allow the liciuid, S'iSTEiM IN THE WORK 329 flowing from lioth at the same time, to be caught in a spout which emptied into the barrel on the lower level. The two solutions, simultaneously flowing into this spout, form Bordeaux mixture during their flow along the spout; the precipitate, being extremely fine, passes through the cheesecloth strainer stretched over the top of the barrel. The contents of the mixing vessels were, in turn, transferred to the spray tank through a pipe, connected with the lower part of the barrel and extending, at right angles to it, over the spray tank, and being directed into it by means of a short ell. The flow of the Bordeaux mixture through the pipe was con- trolled by means of a brass valve. In this way, a perfect mixture is Fig. 186. — A spray mixing platform ami imh M ' nf n^i ! li\ flu \ ^ Dept of Agri- culture at Honeoye Falls, N. Y. The only liftiiifi; iir (--iij w ith this outfit was that involved in transferring the stock solutions to the mixing barrels. obtained, since the reaction takes place in the short spout and on the strainer, and is continued in the mixing barrel and in its transfer from it to the spray tank, where it passes through a brass strainer before flowing into the sprayer {Fig. 185). Where flowing water is available, the only lifting involved with such a platform and supply of barrels is that of transferring the necessary volume of the stock solutions to the dilution barrels; the remaining operations being all accomplished by gravity, except that the water used for diluting the stock solutions, flows into them under pressure. On a mixing platform, constructed at a later date, the water supply was obtained by gravity from a storage tank mounted on an upper bench of the platform. The storage tank, in this case, was filled from a well beneath by a power pump (Fig. 186). 330 FUNGICIDES AND INSECTICIDES "Stock Solutions. — ]Mueh valuable time may be saved by maintaining a constant supply of stock solutions on hand. Stock solutions are highly concentrated solutions of copper sulfate and lime kept in separate vessels. They are usually made so that each gallon of the solution represents a pound of the ingredient of which they are composed; hence, if one wishes to make up 50 gallons of Bordeaux mixture, he takes 5 gallons from each stock vessel and pours them into the dilution barrels — this will represent the amounts called for in the 5-5-50 formula. Stock solutions may be made that represent 2 pounds of copper sulfate or lime per gallon, or in the case of the copper sulfate, one may make what is known as a saturated solution, that is, one to which an excess of the copper salt has been added. A gallon of such a solution is said to contain somewhat less than three pounds of the copper salt. Owing to the fact that a gallon of the saturated solution represents two and a fractional part of a pound, and therefore is less easily measured out, it is not recommended. A saturated stock solution has one advantage over an unsaturated one in that it is not necessary to account for the moisture lost through evaporation, as is the case with the latter. Losses occurring in the less concentrated stock so- lutions may be rectified by marking the height of the solution in the barrel when through spraying, and bringing it up to this mark when spraying is resumed. Stock solutions may be kept almost indefinitely, Init it is never advisable to hold over unused Bordeaux mixture; it should always be freshly prepared. Another precaution to be observed is to always thor- oughly stir up the stock solutions before measuring out the quantities required in making a fresh lot of Bordeaux mixture. This precaution is especially pertinent in the case of the lime, as severe burning of the foliage is certain to result if only the clear lime-water liquid is taken to make Bordeaux mixture." Application of Bordeaux Mixture. — Maximum results from proper!}' made Bordeaux mixture can only be obtained under the following conditions : 1. Its application at the proper time. 2. Its application under sufficient pressure and through properly constructed spray nozzles, so as to give a fine, even distribution of the spray material. 3. Applications sufficiently often to keep tlie new foliage thor- oughly covered. 4. Use poison with the mixture when it is desired as an insecti- cide as well as a fungicide. It is difficult to lay down any fixed rules as to the proper time to spray except in a rather general way. In localities where late blight is common and usually prevalent, it is a good practice to begin spraying as soon as the plants are from 8 to 10 inches high. This is usually sufficiently early to arrest the development of early blight and to afford some measure of protection against flea beetle injury by serving as a repellent. Subsequent spraying should be frequent enough to keep the new growtli well covered with the PYROX 331 fungicide. Wlien the weather is dry and hot, the sprayings may be less frequently made than when the opposite conditions prevail. Bordeaux Paste. — Bordeaux paste is a commercial Bordeaux mixture product from which the excess moisture has been removed ; it is offered to the trade in various sized packages np to a large sized keg. All that is necessary to convert it into a Bordeaux mixture is to add the required amount of water. It is not as efficient in the prevention of late blight as is fresh, home-made Bordeaux mixture when properly made. This is largely due to the fact that the Bordeaux paste forms a coarser precipitate, and consequently gives much the same result as the poorly made Bordeaux mixtures previ- ously described. Dry Bordeaux contains the copper sulfate and lime in a dry, povvdered form, and is intended to be applied as a dust. Bird- recommends the following method of preparing dry or powdered Bordeaux. Dissolve 10 pounds of copper sulfate in 4 gallons of hot water. Slake 5 pounds of quicklime in 4 gallons of water. Slake remaining lime (full barrel minus the 5 pounds) to a per- fectly dry dust. Pour the copper and the milk of lime solutions together, simnltaneoushr, into a third vessel, and stir until no greenish streaks appear; then distribute the mixture over the lime dust and mix with a rake. While still somewhat damp, rub it through a sieve and spread out to dry. This requires a day or two, after which the mixture will keep indefinitely. These quan- tities make aljout 200 ])ounds of powder. Commercially prepared Bordeaux powder is a regular article of commerce, but as yet it has not come into much favor in potato spraying. This statement should not, however, be taken as a final verdict in regard to the use of Bordeaux powder as a fungicide for the potato crop. The constant improvement that is being made in dust spray equipment has made these fungicides much more effective in the control of plant diseases. Dust sprays adhere best when applied in the early morning or late evening, when the foliage is moist with dew. Pyrox is a proprietary compound possessing both fungicidal and insecticidal properties. It is a more expensive fungicide than Bordeaux mixture, and does not give quite as good results as the fresh, properly prepared, home-made Bordeaux. The heavier initial cost of Pyrox is, to some extent, offset by the fact that it is immediately availal)le for use upon the addition of the required 332 FUNGICIDES AND INSECTICIDES volume of water, and, in addition, contains sufficient poison to serve as an insecticide. Use at the rate of 10 pounds to 50 gallons of water. Bug-Death. — The manufacturers of bug-death claim that it is an effective fungicidal and insecticidal compound : but wherever it has been carefully tested it has not fully protected the foliage from late blight, in fact it only gave slight protection. When used liberally, it does control leaf-eating insects. It is too expensive to use as an insecticide, at least in commercial fields. Fungicides Controlling Tuber Diseases. — It is realized that this caption is rather misleading since there are tuber diseases that cannot be controlled by fungicides. It is hoped, however, that its use in this connection may be justified on the basis of conformity to the other terms employed ; as, for example, fungicides are employed as disinfectants, their function being to destroy the fungous organisms causing common scab, and the black scurf or rhizoctonia; also to destroy other spores, particularly those of blackleg, which may be lodged on the outer surface of the tuber. The function of these fungicides ceases with the destruction of such organisms as have been mentioned, which occur on the seed tuber itself. If the disinfected tubers are planted in soil free from the organisms of common scab or of rhizoctonia, the resultant crop of tubers should be free from these two diseases; but if the soil is infected, the new tubers are also likely to be infected. Treatment of the seed tubers, therefore, simply destroys the organisms of these diseases upon the surface of the tuber. It is a guarantee of a clean crop only when the land in which they are grown is free from infection. Corrosive Sublimate Treatment. — Corrosive sublimate was the first fungicide to be successfully emi)loyed in the disinfection of seed potatoes of the disease known as the common scab. It was first successfully employed by Dr. H. Ij. Bolley, of the North Dakota Experiment Station, when connected with the Indiana Experiment Station in the late eighties. The formula recommended for potato seal) and rhizoctonia disinfection is as follows : Dissolve 4 ounces of corrosive sublimate (Mercuric chloride, Hg CL) in a small quantity of hot water in an earthen, porcelain or wooden vessel and dilute to 30 gallons of water. Hot water is suggested as a solvent, because mercuric chloride dissolves very slowly in cold water. In many instances the indifferent results that have been secured from corrosive subli- FORMALIN TREATMENT 333 mate treatment have been due to the fact that the crystals or powder have not gone into solution, hence it was too weak to be effective. Be sure that the material all goes into solution. The quickest way to dissolve it is to place the porcelain vessel containing the crystals and the water over a free tlame or on a hot stove, and let it come to a boil. In the use of corrosive sublimate it should be remembered that the substance is a deadly poison. Every vessel, therefore, with which the solution has come in contact should be thoroughly cleansed before using it for other pur])oses, and every precaution should be taken to ])revent accidents througli the drinking of the solution by farm animals. All discarded material should be so disposed of as to quickly disappear in the ground. An ounce of prevention is better than a pound of cure. The period of treatment of the seed tubers in the corrosive sublimate solution varies with the condition of the seed. If the seed stock is free from the sclerotia or resting bodies of rhizoctonia and comparatively free from common scab, an immersion of one-half hour will be sufficient. If the tubers are badly germinated, the period of treatment should be cut down to a half hour to avoid serious injury to the new sprouts. Where there is considerable rhizoctonia infection and the tubers are dormant, a treatment of one and one-half to two hours is advisable. As soon as the tubers are treated they should at once be spread out to -dry. It is always advisable to treat seed stock before cutting it. Recent investigations have shown that the strength of corrosive sublimate rapidly decreases with each lot of treated seed. It is now suggested that not more than three lots be treated in the same solution witliout reinforcing or renewing it (Figs. 187 and 188). Formalin Treatment. — Formalin is a trade name applied to a 40 per cent solution of formaldehyde gas. It is a non-poisonous, colorless liquid, much more easily Imndled than corrosive sublimate and practically as effective in combating scab ; but it does not seem to have the same penetrative power as corrosive sul)limate when it comes to destroying the resting felt-like bodies (sclerotia) of rhizoctonia. It was first employed as a remedy for potato scab by Dr. J. C. Arthur, botanist of the Indiana Experiment Station. The actual experimental studies determining the best strength of solution to use, and the most satisfactory period of treatment were worked 334 FUNGICIDES AND INSECTICIDES out by the writer, under the direction of Dr. Arthur, during the winter of 1895-96.^ Badly scabbed tubers were treated in formalin solutions of 1 to 200, 1 to 400, and 1 to 800 strengths and the tubers grown in sterilized soil in a small greenhouse connected with the botanical laboratory. The 1 to 200 strength was the only one that gave clean progeny. The formula now used, 1 pint to 30 gallons of water, is approximately 1 to 240. Period of Treatment. — The period of treatment usually recom- mended is one and one-half to two hours; but recent studies have demonstrated that a much shorter period, one-half to one hour, is Fig. 187. — Treating seed potatoes with corrosive sublimate solution. The use of the slat crate as a receptacle is a time saving proposition because the potatoes will dry off in the crates after their removal from the solution. It also prevents re-infection through their coming in contact with an unclean package. Courtesy of Daniel Dean, Nichols, N. Y. satisfactor}^ The shorter period should be used when the tubers to be treated are germinated. When they are dormant and have much scab or rhizoctonia infection, immerse the seed from one and one-half to two hours. After treating the tubers spread them out to dry. Insecticides Controlling Leaf-chewing Potato Pests. — It is well known to every potato grower tliat the leaf-chewing insects are more easily controlled by insecticides than the sucking insects. This is due to the fact that they are readily destroyed by the application of poisonous substances to the foliage. Arsenical poi- sons are chiefly employed in the control of leaf-chewing insects. The poisons most commonly employed are Paris green, arsenate of lead, arsenoids, calcium arsenate, arsenite of zinc, pyrox and bug-death. Paris Green. — The insecticide so widely known under the name of Paris green is a precipitate of white arsenic and acetate of PARIS GREEN 335 copper {verdigris) . It may be prepared by making a boiling bot solution of each of these two substances in separate vessels, and then pouring them together, whereupon the substance we know as Paris green is precipitated in the form of a very fine, clear, green powder. Its value as an insecticide is due to its arsenical content. Nearly all of the arsenic it contains is insoluble in water. Paris green may be applied as a liquid or a dust spray (Fig. 189). When applied as a liquid spray, it should be used in connection with Fig. 188. — Treating seed potatoes on a large scale in a corrosive sublimate solution. Tank filled with 165-pound sacks of potatoes. In this case heavy lifting is avoided by use of pulley blocks. Platform at rear of tank is used as a draining board when sacks are removed. Caribou, Me., 1914. milk of lime equal to 2 pounds of lime to 50 gallons of water, or in Bordeaux mixture to guard against injury to the foliage from the slight amount of free arsenious acid that may be present. It should be used at the rate of 8 ounces to 50 gallons of water. If the insects are abundant and the poison can be added to Bordeaux mixture, it may be used at the rate of a pound to 50 gallons, without risk of injury to the foliage. The dry poicder is most conveniently brought into suspen- sion in water by first making a paste of the Paris green. This is very quickly accomplished by placing it in a small vessel, and adding just enough water to thoroughly moisten the whole mass. Through constant stirring it is soon brought into the condition 336 FUNGICIDES AND INSECTICIDES of a paste, in which state it readily mixes with water. When used as a dust spray, it should be mixed with some neutral substance, such as air-slaked lime, land plaster or any other jjowdered material which will act as a carrier of the poison. There is no generally accepted formula concerning the rate of dilution of the dry form; in fact, the recommended rates vary from 1 pound of Paris green in 19 pounds of the diluent to 1 pound in 99 pounds — with Fig. 189 — Applying a du«t spray of Pari^ 'i i i ' i - ' potato plants to protei't iIkmii as^ainst the ravage-, n i i ( i I p ,i ii ) I" t 1,1 beetle, either or both of which nuiy c luie serious injiirv to tht iil uit-, ju-,t .Utci tin \ ai)i)i:ir above ground. all the intermediate strengths. Very good results have been ol)- tained when diluted to 1 in 30 parts. Occasionally, growers are found who apply dry Paris green without diluting it. In such cases, it is applied with hand atomizers which deliver a very fine dust. It has been used in this way at the rate of from 5 to 6 pounds per acre with but slight injury to the foliage. Such prac- tice is both wasteful of the insecticide and dangerous to the health of the plant, and should never be recommended. Diluted Avith lime or other carrier and a])plied with a dust spray gun, when the foliage is moistened with dew in the early morning or late even- ing, it adheres well to the foliage, and is effective in destroying the leaf-cliewing insects. CALCIUM ARSENATE 337 Arsenate of lead is a precipitate formed by the admixture of solutioijs of arseuate of soda and acetate of lead. Forbush and FernakP published the following statement concerning arsenate of lead : "Although nearly all poisons known to lis which can be used as insecticides have been experimented with during the past five years, in the hope that something would be found which would prove fatal to the gypsy moth, only one which is more ell'ective than Paris green has been di^covered. This is arsenate of lead, a poison slower in its action than the other, but Avhich has tliree distinct advantages: ( 1 ) It can be used at any desired strength without serious injury to the foliage. (?.) It is visible wherever used, as it forms a whitisli coating on the leaves. (3) It has adhesive qualities, given it probal)ly by the acetate of lead, and therefore remains on the leaves for a much longer period than Paris green." The formula used by the commission in making tlieir arsenate of lead consisted of 30 parts of arsenate of soda and 70 parts of acetate of lead. Fernald further suggests that it may be pre- ])ared in the proportion of 11 ounces of acetate of lead to 4 ounces of arsenate of soda. Both substances are brought into solution in separate vessels, and then poured slowly together into a third, the precipitate thus formed being the arsenate of lead. Arsenate of lead is now commonly offered to the trade in the paste and in the dry or powder form. The paste is a little more convenient to use, as it is readily diluted with water to the desired strength. Its selling price per pound is less than the dry form, but a much greater amount must be used in order to secure the same effectiveness, which makes it, in reality, somewhat more expensive than the powder form. In order to be effective against potato insects, arsenate of lead paste must he used at the rate of 3 to 5 pounds in 50 gallons of water. In the dry form, 2 to 3 pounds is sufficient. The difficulty of mixing the dry arsenate of lead with water may be overcome by wetting the mass. Then stir into a thick paste before diluting. Calcium Arsenate. — This relatively new arsenical insecticide is being used as a substitute for arsenate of lead or Paris green to control the potato beetle. The manufacturers claim that it contains more arsenic than the arsenate of lead powder, and that, in consequence, three-quarters of a pound of it is equal to one pound of the arsenate of lead powder. When used alone as a liquid spray, it is recommended that an equal amount of hydrated lime be used 22 338 FUNGICIDES AND INSECTICIDES with it. Use at rate of one and one-half to two and one-half pounds to 50 gallons of water or Bordeaux mixture. Arsenoids. — In some sections of the country and particularly in Aroostook County, Maine, arsenoids have been used very exten- sively in combating the potato beetle. There have been offered to the trade, at various times, preparations known as white arsenoid, pink arsenoid, green arsenoid, etc. Morse'' describes these arsen- oids as follows : " White arsenoid was supposed to be barium arsenite, but all of its arsenious acid was free, so that it was no better than white arsenic diluted with barj'ta. Pink arsenoid is arsenite (not arsenate) of lead. The green arsenoid or arsenite of copper, if pure, would carry about 53 per cent of combined arsenious oxide." Other arsenoids under numbers 2, 3, 4 and 5 are discussed, and the author summarizes the results of his experiments with these insecticides in the following statements : " There was not much difference to be seen in the way the different arsenoids acted. None of them, at the rate used, burned the foliage; and they all killed the insects practically as well as Paris green. The arsenoids are more bulky, and on this account are more readily kept in suspension than Paris green. The field notes show the arsenoids to have been about as effective as Paris green, but not so effective as arsenate of lead." Arsenite of zinc is a compound of zinc and arsenic, and is not so well kno^vai as the arsenate of lead, as it is a nev>'er compound. It is one of the most effective insecticides. It is a whitish precipi- tate or powder that readily mixes with Avater. The adhesive properties of arsenite of zinc are as good, if not better, than that of the arsenate of lead. Used at the rate of 2 pounds to 100 gallons of water it has proven as effective as much larger amounts of arsenate of lead, but it is somewhat more expensive per pound. It is readily mixed with water, stays in susjiension well, and never causes any burning of the foliage. Pyrox. — As previously noted under fungicides, pyrox is a com- bination fungicidal and insecticidal preparation, and should never be used except when intended to control fungous diseases as well as insect pests. Insecticides Controlling Sucking Insects. — Sucking insects are provided with a strong beak or proboscis which they insert into the tissues of the plant and remove its Juices. It is evident, therefore, from the manner in which they secure their food supply. KEROSENE EMULSION 339 that arsenical poisons are not effective against this class of insect enemies of the potato. In order to successfully combat sucking insects, it is necessary to employ what are commonly known as contact insecticides, that is, insecticides that will kill by direct contact through corrosive action, or through a volatile oil. Vola- tile oil compounds are not ordinarily employed in spraying pota- toes, hence they are not considered in the present discussion. The commonly employed insecticides are nicotine sulfate or black- leaf 40, kerosene emulsion, and whale-oil soap. Black-leaf 40 is a proprie- tary compound of nicotine sul- fate, a powerful narcotic jjoison. In color and general physical properties it very much resembles a low grade, black- strap molasses. It may be used at the rate of 1 pint to 50 gallons of water. On account of the ease with which black-leaf 40 can be prepared for use, it has become a very popular insecti- cide for the control of the potato aphid and other suck- Fig. IOO.-A type of sprayer called ino* insects atomizer. (School and Home Gardening.) Kerosene Emulsion. — Although kerosene emulsion is one of the oldest of our home-made contact insecticides, it is not very generally employed. This, I believe, is due to the difficulty that most people encounter in the preparation of an emulsion from which the oil does not separate. Various formulas have been suggested from time to time for its preparation. In general, these formulas differ only in the quantity of soap to use. For example, "Cook's hard soap emulsion" calls for one-quarter of a pound of hard soap such as Ivory, Babbitt, etc., dissolved m two quarts of boiling water, to which is added one pint of kerosene oil. The oil and soap solution is emulsified by pumping it back and forth with a hand pump while it is hot, until a perfect emulsion is obtained. This emulsion is diluted with twice its volume before using. 340 FUNGICIDES AND INSECTICIDES The Ilubbard-liiloy Kerosene Emulsion calls i'or the follow- ing amounts : Hard soap Va pound Kerosene 2 gallons Boiling soft water 1 gallon This formula is prepared in the same way as the Cook formula. In the matter of dilution, however, tlio recommendations are different; this stock solution should be diluted witli from 4 to 20 parts of water. The latter dilution should be used in spra^dng potato plants. Fin. 191.— A bucket sprayer for very small patch- es (Fightsof the Farmer.) ]n2. — Knapsack Sprayer, carried r)f the operator. (Fights of the Britton^ recommends a still different formula wliuli \\v claims gave better results than those ordinarily used. This formula calls for somewhat larger amounts of soap and kerosene : Laundry soap (about ;10 oiuices) 3 cakes Kerosene 4 gallons Water 2 gallons Emulsify as ])reviously direcled and dilute eiglit times, prac- tically a 50-gallon barrel. Britton says: "All the ai)hi(ls liit by the spray were killed without injury to the ])lants." Whale-oil Soap. — The value of whale-oil soap as an insecticide for sucking insects has long been recognized. Tt is effective against plant lice when used at tlic rate of one pound to 10 gallons of water. The soap should be shaved into tbin slices, dissolved in a small volume of l)oiling liot water, and iben diluted CONTROLLING TUBER-EATING INSECTS 341 to the required strength. Whale-oil soap may also be used in place of hard soaps in making kerosene emulsion. Suggestions for Spraying Aphids. — The value of any of the above spray materials in the control of sucking insects is directly de])endent upon the thoroughness with which it is applied. This statement is particularly true with the potato aphid which, as a rule, feeds upon the under surface of the leaf, oftentimes causing it to roll downward and inward. The spray material must be so directed as to reach and cover the under surfaces of the leaves. This can be most conveniently accomplished, when the plants are large, by suspending a rod or other device beneath but slightly in ad- vance of the spray nozzles, and sufficiently low to drag the tops over; this exposes the lower surface of the leaves to the spray material, provided the nozzles are ])roperly adjusted. Injury to the vines, from being dragged over in tliis manner, may be minimized by slipping a slightly larger pipe over the suspended rod, so as to permit a revolving motion as tlie plants are bent over. Insecticides Controlling Tuber-eat- ing Insects. — The only insect pest of the tuber that can be destro3^ed by a gaseous compound is the potato tuber moth. Treatment can only be applied when the crop is in storage, and the storage house or room is sufficiently tight to hold gas for a reasonably long period. The substance used is a colorless liquid known as carbon bisulfide. Graf recommends the following dosage: two pounds of carbon bisulfide to each 1,000 cubic feet of air space; expose to fumes for 48 hours. Graf says that at this strength the larvs and adults and practically all the pupse and eggs are killed. If the tubers are noticeably infested, the fumigation sliould be repeated in a week, if in summer, or in two Aveeks in winter. It is suggested that the liquid should be placed in shallow tin pans above the material to be treated, as the gas is heavier than air. Carbon bisulfide gas is a highly explosive compound when mixed with air, therefore, Fig. 193. — Compressed air sprayer. This type of sprayer fills about the same need as the knapsack type. 342 FUNGICIDES AND INSECTICIDES care should be exercised not to have it come in contact with a flame or spark. Resultant Benefits from Fungicides and Insecticides. — The resultant benefits from the use of fungicides or insecticides have, so far as we are aware, only been determined in the case of the late blight. It is obvious, of course, that equally striking data might be collated with reference to the injury caused by insects, and particularly so by the potato beetle. In fact, it is conceivable Fig. 194. — Barrel spray pump mounted on hand cart. Fairly efficient sprayer for relatively small commercial areas. that the crop might be entirely destroyed, so far as the production of marketable tubers are concerned, if not protected from the ravages of insect pests by some arsenical application. The most interesting data upon this subject are those published by Lutman^ in which the author discusses the results of 20 years of spraying with Bordeaux mixture, applied to late matur- ing varieties of potatoes, for the control of late blight, by his pre- decessors in the work. These results, as summarized on page 247, represent gains from the use of Bordeaux mixture, ranging from 32 bushels per acre in 1906, to 224 bushels per acre in 1893. The total average yield per acre from the sprayed plants for the 20 years was 268 bushels per acre, and 163 from the unsprayed plants, a gain of 105 bushels per acre or 64 per cent. SPRAY EQUIPMENT 343 At the New York State Experiment Station in a ten-year spraying test, 1902 to 1911 inclusive, at Geneva, and Eiverhead, L. I., the following average increases from 3 and 5 to 7 sprayings were obtained : Geneva, N. Y., 3 sprayings resulted in an increase over unsprayed plants of 69 bushels per acre; 5 to 7 sprayings 97.5 bushels; Eiverhead, 3 sprayings 25 bushels, 5 to 7 sprayings 45.7 bushels. Many other instances might be cited where much larger gains from spraying were obtained. One of the most striking examples Fig. 195. — The sprayer in operation. When the phmts are full grown the spray boom should be raised high enough to permit of a wide and even distribution of the spray material. Presque Isle, Me. that has come to the writer's attention of benefit derived from thorough spraying with Bordeaux mixture on a commercial scale, is reported by Dean* for the years 1912, 1915 and 1917. These were years in which severe epidemics of late blight rot occurred. In these three seasons Dean sprayed his crop 14, 8 and 11 times, respectively, and, as a result thereof, secured increases over un- sprayed plants of 183, 200 and 213 bushels per acre. It should be said that such increases are possible only where the spraying is thoroughly done, and where cultural conditions are satisfactory to the production of a large crop. Spray Equipment. — The development of spray equipment has practically kept pace with that of the chemist in the manufacture of new fungicides or insecticides. Broadly speaking, spray equip- 344 FUNGICIDES AND INSECTICIDES meiit may be roughly classified under two heads, viz., liquid and dust sprayers. Liquid spray equipment may in turn be divided into hand, tractor, and gasoline-driven pumps. Hand equipment may consist of a hand atomizer, bucket pump, knapsack sprayer. Fig. 196.— a l \ j Manufacturing Co. Fig. 197 . . niounted in front of spray tank, Spray outfit hauled by horses, pump operated by Courtesyof Bateman Mfg. Co. gasoline engine auto-spray, and barrel-pump sprayers. The tractor-driven sprayers consist of one- or two-liorse machines of from 50 to over 100 gallons capacity, the pump of which is operated by being geared to one or both wheels of the spray cart. Such machines, when the valves are properly packed, are capable of developing from 125 SPRAY EQUIPMENT 345 to 200 or more pounds of pressure. Gasoline-driven spray equip- ment consists of spray machines hauled by horses or tractor with gasoline-operated pump. With such machines it is possible to develop from 200 to 300 pounds pressure per square inch. With such a pressure and proper nozzles the liquid spray is broken into such fine particles that it resembles a fog or fine mist. When applied in this manner, properly made spray materials are much more effective in the control of fungous or insect pests than with a pressure of 75 to 125 pounds. Dust sprayers or blowers are receiving much more favorable attention at the ])resent time than in the past. The manufacturers A traction-power dust spray machine in action. Courtesy of Niagara Sprayer Co. of dust blowers are constantly perfecting their machines and we may look forward to a much larger use of dust sprays in the future. (S'pray Equipment Classification. Liquid Spray Equipment Hand-operated equipment Trac'tor-operated equipment Gasoline-operated eciuipment Hand-operated Tractor-operated Atomizer (Fig. 190) Bucket pumps (Fig. 191) Knapsack sprayers (Fig. 192) Auto-spray tanks (Fig. 19.3) Barrel pumps (Fig. 194) Horse-drawn sprayers with pump oper- ated by wheel gears (Figs. 195 and 196) Spray machine hauled hy horses or trac- tor; pump operated by gasoline en- gine (Fig. 197) Dust Spray Equipment Atomizers Blow guns Bellows One- or two-horse tractor-driven dust sprayers (Fig. 198) 346 FUNGICIDES AND INSECTICIDES QUESTIONS ON THE TEXT 1. How are the fungicides and insecticides grouped? 2. Give a list of the commonly used preparations for foliage diseases. 3. What are the two commonly employed fungicides used for tuber disinfection? 4. What are some of the insecticides used for the control of leaf-chewing insects? 5. What three insecticides are recommended for sucking insects? 6. What is recommended for tuber-infesting insects? 7. Give the steps in discovery and development of Bordeaux mixture. 8. What is the present standard formula for use on potatoes? 9. What constitutes a good Bordeaux mixture? A bad Bordeaux mixture? 10. Upon what does the fineness of the precipitate depend? 11. What happens when the milk of lime is added to a concentrated copper solution? 12. To what is improperly made Bordeaux mixture largely due? 13. What are the advantages of a convenient spray mixing platform? 14. What is meant by a gravity system of Bordeaux mixing? How does it help? 15. What are stock solutions? How are they prepared? 16. In what way can maximum results be obtained from a properly made Bordeaux mixture? 17. In localities where late blight is common, when should spraying begin? 18. Discuss Bordeaux paste and dry Bordeaux and their uses. 19. Compare Pyrox as a fungicide with Bordeaux mixture. 20. Is bug-death etjual to Bordeaux mixture as a fungicide? 21. What fungicides are employed in disinfecting seed potatoes? 22. Give formula for the preparation of the two solutions and the time of immersion for black scurf. 23. Should the seed stock be treated before or after cutting? 24. Compare leaf-chewing insects and sucking insects in their ease of control. 25. What is Paris green? 26. How is it usually employed, and in what strength? 27. When employed as a liquid spray, what precaution should be observed in order to avoid foliage injury? 28. How may the dry powder be most readily mixed with water? 29. Give directions for mixing and use as a dust. 30. When is the best time to apply dust sprays ? 31. What is arsenate of lead? How is it manufactured? 32. Compare the powder and the paste forms, and give relative amounts to use. 33. What is calcium arsenate, and how does it compare in effectiveness with arsenate of lead? 34. Compare the arsenoid insecticides with arsenate of lead in effectiveness. 35. How does arsenite of zinc compare in effectiveness with arsenate of lead? 36. How are sucking insects controlled? 37. What are the three commonly employed contact insecticides? 38. What is black-leaf 40? How used? 39. How is kerosene emulsion prepared? 40. Of what value is whale-oil soap in combating sucking insects? 41. Upon what does the value of ccmtact insecticides largely depend? REFERENCES CITED 347 42. What results were secured at the Vermont Station from the use of Bordeaux mixture? 43. What results were secured at the New York State Station? 44. What increases did Dean secure from spraying? 45. How may liquid spray equipment be classified? 46. Describe each group or class of spray equipment. 47. What types of dust spi-ayers have we? QUESTIONS AND EXERCISES SUGGESTED BY THE TEXT 1. Make a list of combined troubles for which we should use combined sprays — insecticides and fungicides. 2. Give the combined sprays to use in each case. 3. Make a list of the diseases and insects which are likely to give trouble to local crops. 4. Make a season's spray calendar showing the troubles, remedies and times for use in your region. 5. Inquire from local growers and determine the numbers of applications of sprays for the worst enemies. 6. Make a local study to determine the degree of effectiveness of various treatments and materials tried by growers. 7. Make a collection of materials described in this chapter. 8. Make up small quantities of stock solutions of Bordeaux. 9. Make good Bordeaux, and bad Bordeaux. Compare. References Cited 1. Arthxir, J. C. 1897. Formalin for prevention of potato scab. Jnd. ma. Bui. 65, June, 1897. 2. Bird, R. M. 1905. Directions for making Bordeaux powder. Mo. Bta. Circ. Inform. 20: 1-4, April, 1905. 3. Britton, W. E. 1918. Insects attacking the potato crop in Con- necticut. Conn. (New Haven) Sta. Bui. 208: 117. 4. Dean, Daniel. 1918. Potato spraying as a war "bit." The Pot. Mag. 1 : 3, 4, 20, July, 1918. 5. FoKBusH, E. H., and C. H. Ferxald. 1896. The Gypsy Moth (Proth- eria dispar Linn.) Mass. Bd. of Agr. Spec. Rpt. 1896: 141-142. 6. Graf, J. E. 1917. The potato tuber moth. U. H. Dept. Agr. Bui. 427: 20. 7. LuTMAN, B. F. 1911. Plant diseases. Twenty years spraying for potato diseases. Yt. Hta. Bui. 159: 225-247, May, 1911. 8. MiLLARDET, A. 1885. Annates d' I' 8oc. d'Agr. d' V Gironde: 73, April, 1885. 9. Morse, W. J. 1900. Experiments with insecticides upon potatoes. Me. Sta. Bul. 68: 177-179, 1900. chai>t]!:h xviii industrial uses of the potato in america and foreign countries The value of any food crop for industrial purposes and par- ticularly a perishable one, is largely determined by the cheapness of its production ; its chemical composition ; the number of valuable constituents embodied in it ; the ease with which these elements may be converted into commercial products; and last, but by no means least important, the market outlet for its products. Constituents of the Potato. — Chemical analysis of the potato shows that it contains approximately 75 to 80 per cent of water, 14 to 20 per cent of starch (occasionally this amount may reach 23 to 25 per cent), 1.5 to 2 per cent of proteins, and 2 to 3 per cent of fibre and mineral salts or ash. Its value, both as a food and in the industries, is due to its starch content. Starch occurs in many other crops besides the potato, of which the most important commercially are corn, cassava, rice, sago, arrow-root, and wheat. Potato Products. — Thus far, the chief manufactured products consist of potato starch, potato flour, dried or deliydrated potatoes, dextrine, glucose, dextrose or starch sugar, alcohol and lactic acid. There are, doubtless, other possible uses of potatoes. The process of starch manufacture is a relatively simple one consisting of thoroughly washing the potatoes; grinding or grat- ing them into a fine pulp ; wasliing the starch from the fibrous material of the potato through fine sieves; collecting it in large vats, where by changes of water the impurities are separated from the starch. The starch settles to the bottom of the vat, from whence, after the liquid has been drawn off, it is removed to the drier and subjected to heated air until the moisture content is reduced to about 18 per cent. The requirements for starch manufacture on a commercial scale are an abundant supply of pure water, a clieap l)ut commodi- ous l)uilding, having a reasonable storage capacity, conveyors to convey the potatoes to the washer and grinder, sieves for separating the fibrous parts from the starch, several settling tanks of rather large capacity to purify the starch, .and a drier ])rovided witli steam or flue heat for drying the starch. 348 DOMESTIC PRODUCTIOxN OF POTATO STARCH 349 The dried starch may he marketed in 200-pound sacks or 500- pound wooden casks. Starch Yields. — The average yield oC commercial starcli from cull potatoes in the United States is ai)proximately 15 per cent of the weight of the raw material, that is 15 pounds per hundred- weight of potatoes, or 9 pounds per bushel. The yield from good, sound, well ripened tubers of varieties averaging 20 per cent of starch is correspondingly greater. Uses of Potato Starch. — Tlie uses or connnercial outlets for l)otato starch, or in fact any starch, may be roughly divided into three classes: (1) for edible purposes; (2) for laundry purposes; (3) for manufacturing purposes. 1. Starches are used for edible purposes in ])ud(lings, confection- ery, pastry, and as a stiffener for ice cream, custard, i>ie fillings, and in sausage and blood ])udding making. For the last two mentioned products potato starch is considered far superior to other starches, on account of its greater swell or ex])ansive power, and the firmness that it imparts to the product. For the otlier ]»urposes corn starch is more largely used in this country, chiefly, it is believed, on account of its clieapness ; and partially, no doubt, due to the fact that the manufacture of high grade ])otato starch has not heretofore been seriously attempted by American starch manufacturers. 2. The use of potato starcli for laundry ])urposGs may be re- garded as practically nil in this country, l)ut it has a large use in European countries. 3. Tlie superiority of potato starcli for certain manufacturing purposes is clearly recognized. Tlie higher viscosity of pro])erly dried potato starch makes it more desirable to use in the sizing of high grade fabrics. In lower grade fabrics its increased price over that of cornstarch makes its use more or less prohibitive. It is generally admitted that potato starch makes the best grade of dextrine now produced. Domestic Production of Potato Starch. — The most inii)ortant use that has yet been made of the potato in this country, in an industrial sense at least, is that of the manufacture of starch. The normal production of starch approximates from 20 to 25 millions of pounds. According to data published by the United States Tariff Commission in 1919, tlie number of establishments reporting the manufacture of starch had decreased from 131 in 1904, to 110 350 INDUSTRIAL DSES OF THE POTATO ill 1909, and 82 in 1914. Potato starch is largely manufactured in Maine, Wisconsin, and Minnesota. Maine is said to produce over 80 per cent of the total potato starch output of the United States; and Aroostook County is the principal centre of the industry. The price paid for cull stock ranges from 25 to 75 cents a barrel under normal conditions, with an average of about 45 to 50 cents per barrel (165 pounds). The following data for 1904, 1909 and 1914 are from figures taken from the Census of Manufacturers; while those for 1915- 1918 were compiled by the cornstarch producers, and taken from the Textile American, December, 1918: Production and value of potato starch and cornstarch in the United States. Number Potato starch Cornstarch Year of factories Pounds Value Pounds Value 1904. . 131 27,709,400 $924,476 311,140,814 $ 8,878,450 1909.. 110 24,873,415 823,019 638,825,366 15,962,916 1914.. 82 23,540,472 718,006 574,247,697 13,784,654 1915. . 775,891,649 1916.. 868,916,578 1917.. 833,131,755 1918. . 481,761,893 These figures indicate that a little over three million bushels of potatoes \vere used in the manufacture of starch in 1904, about two and three-quarter million in 1909, and somewhat less than that amount in 1914, or less than one per cent of the total crop in either of the three periods. It is evident from these data that even potato starch production furnishes but a relatively in- significant outlet for the potato crop of this country. In order to produce a stabilizing influence upon the potato industry, indus- trial outlets must be developed that have the possibility of using from 10 to 20 per cent of the crop. Foreign Production of Potato Starch. — In Germany it is claimed that 4 per cent of the total j)otato crop is used in the manufacture of starch. While this does not seem large when think- ing of it in terms of our domestic crop, it assumes a different value when considered on the basis of over a billion and a half WHY IMPORT STARCH 351 bushel crop; it means that it would require one-sixth of our crop to offset the 4 per cent of the German crop. The following data shows the production of German potato products in 1910-11: German -production of -potato products, 1910-11. Kind of product Potato Wet starch Starch^^ Qj.y gtarch and potato meal [_ Dry & wet washing starch . . Potato sago Potato meal (lump) Glucose Glucose sirup Caramel Dextrine Soluble starch Dried pulp (residue) Wet and steamed pulp Total Quantity, pounds Value 125,671,700 $ 1,424,192 .383,019,708 8,447,810 7,948,905 61,880 5,277,592 168,266 826,725 28,560 21,940,400 550,018 124,332,385 3,104,472 9,673,123 307,734 49,310,288 1,404,914 3,602,096 107,100 27,804,630 144,942 513,556,940 212,295 1,272,964,498 $15,962,184 From Vierteljahrshefle Statistik des Deutschen Reichs, IH, p. 114, Berlin, 1914. Starch Imports. — Prior to the war, Germany and the Nether- lands supplied practically all of the starch imported into the United States. From 1909 to 1913, the imports averaged 13,730,665 pounds, valued at $375,767; and from 1914 to 1918, they averaged 15,143,778 pounds, valued at $704,712. During the war, the imports shifted from Germany and tlie Netherlands to Japan and Canada. Figures for 1917 and 1918 show that Japan's exports of potato starch to this country were 18,008,066 and 21,806,975 pounds respectively, with a valuation of $799,775 and $1,494,131. The total im])orts from all sources during these two years were 20,647,893, and 23,852,145 pounds, or an amount in 1918 equal to our total production of potato starch in 1914. It is claimed that approximately 95 per cent of the starcli imported into the United States is potato starch. Why Import Starch? — The question might well be raised as to the economic reasons for the consumption of foreign-made potato 352 INDUSTRIAL USES OF THE POTATO starch in this country. There is but one logical reason — the uncertainty of a sufficiently large supply of cheap potatoes each season to make possible the profitable operation here of a starch factory. The only seasons in which, under normal conditions, it is possible to manufacture starch at a price sufficiently low to keep out foreign-made starch are when there is an over-])roduction; when late blight rot is prevalent in those sections where starch factories are located; or when, from one cause or another, there is an unusually large percentage of unsalable stock. In seasons when the crop is short, the oidy stock available is that which cannot be disposed of for table purposes. European countries are able to produce potatoes at a sufficiently low cost to permit the starch manufacturers to buy table stock, at prices, tliat in tliis country would mean financial ruin to the growers. POTATO FLOUR The possibility of using potato flour as a partial substitute for wheat flour in bread making was forcibly brought to the at- tention of the American housewife when the plea was made by the U. S. Food Administration to conserve wheat flour by the use of substitutes. Unfortunately, the scarcity of potato flour and its relatively higli cost as compared with wheat flour, together with unfamiliarity in its use, proved to be too great an obstacle to be overcome in such a comparatively short period of time. The interest awakened in its possibilities has not, however, subsided as will be noted under domestic production. Potato Flour Manufacture. — In order to manufacture a high grade potato flour it is necessary to use sound stock. It does not follow, however, that it must necessarily be of No. 1 grade. In fact, it has been demonstrated within the past three years that it is perfectly feasible to make a good quality potato flour from sound No. 2 and cull stock. In seasons of over-production it offers an outlet for the surplus table stock, thereby preventing a total loss to the grower. The manufacture of potato flour requires a greater initial out- lay for both equipment and building than that involved in the production of starch. The cost of building and equipping what is termed a single unit plant requires an initial expenditure of from $20,000 to $30,000 or more, depending upon the character of the building erected, and the amount of storage space ])rovided for the raw material and the manufactured product. POTATO FLOUR MANUFACTURE 353 The machinery consists of a washer, long conveyor, cooker, two spiral screw conve^'ors, flaking machine, blower, grinding mill, and a bolter. The first step in the manufacture of potato flour is identical with that involved in making starch, that is, the potatoes must be thoroughly washed. After passing through the washer they are carried by a belt conveyor to the steam autoclave or cooker, and if an especially fine product is desired, Avomen or girls are stationed along the conveyor to cut or remove all unsound or sunburned mate- rial. In a medium-sized factory the steam cooker used has a load capacity of from 750 to 800 pounds of potatoes. At 240 degrees F. it requires about fifteen minutes to cook the potatoes. The cooked tubers pass from the cooked through a screw or ribbon conveyor to a hopper above the drying cylinders and from thence they pass through a set of rollers Avhich crushes and distributes them in an oven, thin layer on the surface of the steam heated cylinder, which in the course of a single revolution removes most of the excess moisture, and imparts enough heat to the potato to dissipate still further moisture. The thin layer of potato is removed from the cylinder by means of flexible knife blades. The dried flakes are i-emoved from the flaker or drier by means of a screw conveyor which breaks up the material, and it is then elevated to a bin above the grinding mill. The flakes are then ground and bolted, and the flour sacked. The ])otato flour thus secured by this process is, in reality, a cooked product. It embodies all of the chemical constituents of the potato tuber, and thus retains all of the mineral salts, which are generally regarded by dietitians as being highly necessary to the health of the body. In this connection, it is very desirable to remember that, in the past, a large ])ercentage of the potato flour offered for sale in this country was really a ])otato starch flour, that is, starch re-ground and bolted. The legality of such naming has been questioned, and a ruling rendered which makes it a mis- demeanor to brand potato starch as potato flour. The justice of such a ruling is apparent to all. Potato starch flour is practically pure starch. All the mineral salts and protein compounds were lost in the manufacture of the starch ; furthermore, it is not a cooked product and, therefore, even though its composition was identical, it would still give different results when used for the manufacture of bread. 23 354 INDUSTRIAL USES OF THE POTATO Domestic Production. — Had the question been asked prior to the war, one would have been ol^liged to answer that no genuine potato flour w^as being made in the country. In 1918, however, there were five potato flour factories in operation having a com- bined production of two and a half million pounds. The cessation of the war has in part, at least, removed the more urgent incentive to develop a stable potato flour industry. Three of the five facto- ries operating in 1918 are controlled by a large corporation, with sufficient available capital to enable them to spend considerable sums in the education of the public, and particularly the bakers, regarding the value of potato flour in some form in our diet. The following quotation is from an editorial in the February, 1920, issue of the Potato Magazine, p. 20 : "The manufacture of potato flour in this country (United States) is due to become an important factor in tlie potato industry. The Falk Company of Pittsburgh, owning flour manufacturing plants in Michigan, Maine, Colorado, Minnesota, Wisconsin and Idaho, recently contracted with the growers in the vicinity of its Colorado plant to deliver all of their No. 2 potatoes to them for the next five years. For these No. 2's and all odd sizes and shapes that will stay on an inch and a quarter mesh screen, the growers will receive 60 cents per 100 pounds, delivered at the mill While establishing these mills in different commercial potato-producing sections, the company has not been unmindful of the necessity of creating a market for their product. It has issued a number of attractive pamphlets telling the bakers of the advantages of potato flour This has resulted in an excellent sale for potato flour — the newest potato product to be produced in the United States." The future of the potato flour industry depends, in large measure, upon the ability of those engaged in it to create a growing demand for the flour; and to secure a sufficient supply of No. 2 potatoes to enable them to operate their factories over a long enough period each year, thus making it possible to place their product on the market at a reasonably low ])rice. Such price must, of neces- sity, be somewhere near, though probably slightly in excess of, wheat flour. DEHYDRATED POTATOES Through dehydration the potato may be converted into what is commercially known as dried, sliced, cubed, shredded, or riced potatoes. When intended for human food, all dehydration methods involve the partial or complete cooking of the potato. So far as DRIED, RICED POTATOES 355 the United States is concerned, it is a war industry development. In European countries and Germany in particular, the desic- cation of potatoes for human use or stock feed purposes has long been practised. Dried, Sliced Potatoes. — In the manufacture of dried, sliced potatoes, a fair sized potato is necessary in order to secure a goodly percentage of reasonably large slices when dried. The first step in the preparation of the material is the selection of sound stock; the next is the thorough washing of the same; the tliird step in- cludes the paring of the tul)ers which is accomplished by attrition in a power-driven centrifugal machine; the fourth step consists in the hand examination of the pared tubers and the removal of all parts not cared for by the parer; the freshly pared potatoes are then sliced by a slicing machine which cuts them into slices approximately one-eighth to one-fourth of an inch thick. The sliced potatoes are caught on wooden trays with cloth or wire bottom over which they are spread in a thin layer. They are then put into a large steam chest or autoclave for a few minutes, just long enough to cook them sufficiently so that they will not turn dark when being desiccated. The trays are then placed in a drying tunnel or chamber in which the slices quickly dry. Success or failure in the manufacture of dried, sliced potatoes is dependent upon the care exercised in each successive step of the process. A properly made product should retain its color, a light amber or straw color, and when placed in water should swell to its original size and at the same time be firm and brittle rather than pasty and leathery. Dried, Cubed and Shredded Potatoes. — In the manufacture of dried, cubed or shredded })otatoes, the same processes are fol- lowed as in drying sliced potatoes, unless they are intended for stock feed, in which case they may be dried by direct heat in flue gases. Dried, Riced Potatoes. — The production of dried, riced pota- toes differs from dried, sliced potatoes only in the later stages of manufacture. Its preparation is the same up to the point of slicing ; unless the tubers are large they are cooked whole ; on re- moval from the steam chest they are emptied into a large power- operated press, where a large plunger forces the cooked product through a perforated metal plate. The finer the perforations are 356 INDUSTRIAL USES OF THE POTATO in the plate the more attractive will be the product made. A very large proportion of the product turned out by American manufac- turers during the war was riced through perforations at least three-eighths of an inch in diameter. The riced product was col- lected on tra3's, similar to those used in making dried, sliced pota- toes, and placed in drying tunnels. When ])artially dry they arc removed, and run through a machine that breaks up the shreds into shorter lengths; after this they are again returned to the drier, and left until a certain stage of dryness has been reached that Avill insure long keeping. This product was largely used in vegetable soup mixtures. Domestic Production. — It is claimed that in 1918 there were sixteen drying plants, in the United States, engaged in producing dehydrated potatoes, with a combined output of 7 million pounds. Upon the cessation of hostilities, most of the large orders for dehydrated potatoes, placed Avith these manufacturers, were can- celled, wdth the result that this branch of the potato industry bids fair to languish and die. The only possible demand that is now likely to be made for dried potato products will be for the higher grade of dried, riced potatoes, that is, those that have been passed tlirough a very fine ricer, and have been so handled as to preserve a bright color. Such a product is easily prepared for table use, either as mashed potatoes, or for soup. Foreign Production. — The following statistics on the German potato-drying industry, and several other potato products for the years 1908 to 1911, published in Berlin in 1911, indicates the extent of the industry in pre-war times. German Potato-drying JnduHiry. Total number factories Factories using Am't. domestic peeled potatoes unpeeled potatoes and foreign potatoes used 1908-09 1909-10 1910-11 170 254 327 I 4 164 246 323 5,898,774 bu. 12,222,302 bu. 15,345,485 bu. Other German Potato Products. Products Cut and sliced Flakes and meal All others Total 1908-09 1909-10 1910-11 14,263,762 lbs. 35,163,370 lbs. 31,878,516 lbs. 77,072,816 lbs. 157,143,888 lbs. 204,057.776 lbs. 330,690 lbs. 793,656 lbs. 661,380 lbs. 91,667,268 lbs. 193,100,914 lbs. 2.36,597,672 lbs. GLUCOSE PRODrCTION 357 nEXTUIXE, (iUTOSE AND .\L('OFH)L IMiODrCTIOX Dextrine. — Tliis is u jjroduct oi' starch obtained by heating it, either alone or with a diluted acid. It is regarded by some as an intermediate product between starch and glucose. Dextrine is soluble in water and possesses strong adhesive properties. It is sold on the market under the names of potato dextrine, corn dextrine, tapioca dextrine, British gum and burnt starch. The last two terms are generally applied to the cruder product. Method of Manufacture of Dextrine. — As previously noted, dextrine is a ])rodnct ol' heated starch, or of starch treated with dilute acid. It is usually made by heating starch in an oil bath or steam jacket. When acid is used, the starch is moistened with dilute acid and then air-dried ; or else it is heated at a low tem- perature and finally the finely ground product is placed in a suit- able oven, heated with steam. Continuous stirring is necessary to insure a perfect mixture. Acid-treated starch usually makes a lighter colored dextrine, but the sugar it contains lessens its ad- hesive properties. A loss of some 20 to 25 per cent is involved in the conversion of starch into dextrine. This loss is, in part, compensated for through the absorption of moisture by the dextrine. It is claimed that dextrine made from potato starch has a greater adhesive power than that from other starches, and is said to be generally preferred in the textile trades. It also makes a very satisfactory product for gumming envelopes and stamps. Domestic Production of Dextrine. — The United States now possesses the largest ])lants for the manufacture of dextrine. Prior to the war little, if any, potato dextrine was manufactured, produc- tion being limited almost entirely to corn dextrine. In point of value, potato dextrine commands the highest price and corn dextrine the lowest. In 1914, imported potato dextrine brought six to seven cents per pound ; the domestic article sold for five and one-half to seven cents and British gum at three and one- eighth to three and one-quarter cents; while corn dextrine ranged from three to three and one-half cents per pound. In the latter part of 1918, domestic potato dextrine quotations showed that the price had advanced to twenty cents per pound. The tariff on dextrine, (March, 1920), was three-fourths of a cent per pound. Glucose Production. — So far as known, potato glucose is not manufactured in the United States, corn being used instead of the potato. Potato glucose is manufactured on a rather large scale in Europe from potato starch. 358 INDUSTRIAL USES OF THE POTATO Alcohol Production. — The production of alcohol from potatoes is nowhere so extensively practised as in Germany. This statement is well substantiated by the number of farm and industrial stills that were in operation in that country in 1911. Skinner says^ that on this date there were 5,577 farm stills and 17 industrial stills, used principally for the extraction of alcohol from potatoes; against 7,626 farm stills and 710 industrial stills, used chiefly for the extraction of alcohol from grain. Kremers states^ that there are about 6,000 agricultural potato distilleries in operation in the German Empire, 4,000 of which represent one of the chief activities of the respective farms, whereas the remaining 2,000 have a secondary place. THE NEEDS OF THE POTATO INDUSTRY The successful development of any great industry is wholly dependent upon the demand that may be created for its product or products. A business having but one outlet for its product has a much smaller chance of attaining to as large proportions as one that has several. Many industries have been made im- mensely profitable through the by-products, developed from mate- rials that, in the early stages of the industry, had been regarded as waste products. The meat industry of this country furnishes an excellent illustration of what might be practically considered the last word in tlie utilization of waste products. The well-known, but nevertheless trite, remark that the large meat packing houses utilize everything but the squeal of the hog, illustrates in a most forceful manner the business thrift of these large corporations. When similar principles are applied to the utilization of agricul- tural food crops, a long step will have been taken toward the stabilization of production. The potato industry of America has urgent need of such a stabilizing influence; in fact, until outlets are created which will provide a market for the culls, and the surplus stock in seasons of over-production, potato growing will continue to be one of the largest gambling enterprises in which the American farmer can engage. The gambling element in this crop is due to the fact that, practically speaking at least, tlie i)otato has but one outlet, that of table stock. Per Capita Consumption. — The normal per capita consump- tion of potatoes in the United States is difficult to estimate with any great degree of accuracy, on account of the fact that production PER CAPITA CONSUMPTION 359 varies widely from year to year, with a consequent upward and downward movement of prices, all of which tends to curtail con- sumption. One way of estimating the per capita consumption is to take, as a basis for computation, the average annual production of the United States for the five-year period 1915-1919, or 371,- 708,600 bushels and divide it by the average annual population for the same period, which we will assume to be approximately 110 millions of people; this gives us a per capita average of a little less than three and one-half bushels. But such a figure represents per capita production and not per capita consumption. To arrive at the per capita consumption, it is necessary to deduct all stock unfit for table purposes, all diseased and frozen stock, to make allowance for the natural and inevitable storage shrinkage, and last but not least, deduction must be made of the seed necessary to plant the ensuing year's crop. While it is difficult to make exact estimates of the percentages ordinarily involved, it is believed that the figures given are not far amiss if applied over a series of years : Culls or unsalable stock 10 per cent. Diseased, frozen and storage shrinkage. 10 per cent. Seed for ensuing crop 10 per cent. The probability is that the first two percentage figures are too low rather than too high. The last estimate may be regarded as approximately correct. Deducting 30 per cent from the total crop of 371,708,600, leaves 260,196,020 bushels available for consump- tion, a trifle over two and one-third bushels per year, or a per diem allowance of six and one-tenth ounces for each man, woman and child in the United States. Contrast this with a per capita consumption of seven and one-third bushels in Germany, an amount almost three times as great as that used by our own people. As- suming that the figures presented are approximately correct, it is seen that 70 per cent of the potato crop produced in the United States is used for table purposes. In Germany, it is claimed that only 28 per cent of a normal crop is used for table food. The balance of the crop is disposed of as follows : 40 per cent is fed to live stock; 12 per cent used for seed; 10 per cent for industrial purposes; and the remaining ten per cent is regarded as waste, due to decay, shrinkage and other causes. The large balance of the German crop, over and above the actual requirements for table food purposes is available in seasons of low production years, for 360 INDUSTRIAL USES OF THE POTATO human food. It simply means that a lesser amount is used for industrial purposes. This prevents wide fluctuations in prices, such as occur in the United States when there is a short crop. It has been shown in a previous portion of this chapter that somewhat less than one per cent of the crop of this country is converted into starch, and that we have the beginnings of a potato flour and possibly a potato dextrine industry. Just how far it may be possible to increase all three of these industries depends, to a considerable extent, upon the degree of protection they receive from foreign competition, and to our ability to reduce the cost of production by increasing the j)er acre yield. The fact should not be lost sight of that these commodities are being manufa(;tured out of the cull potatoes, with the probability that it will be some years before the industrial uses of the potato will exceed the normal supply of unsalable potatoes. Increased Consumption Desirable. — The only way by which the consumption of potatoes may be increased is to produce a suf- ficient crop each season to guarantee an ample supply for table purposes at a price commensurate with their food value. This would involve a large over-j)roduction during favorable years, for which a profitable outlet would have to be created. Alternate years of high and low production, with their consequent wide fluct- uation in prices are detrimental to both grower and consumer, as well as to the industry itself. When prices are high, the con- sumer substitutes other vegetables or vegetable products, and thus gets out of the habit of eating potatoes each day as a regular part of his or her diet. Production must be increased through the use of better seed and improved cultural practices, therel)y securing larger yields per acre at a reduced cost per bushel. Consumption must be increased through a steady supply of good, sound potatoes, at a price consistent with a fair profit to the producer. Production and consumption must go hand in hand if a stable industry is to be built up. Distribution. — Distribution is one of the important links be- tween the producer and the consumer. Heretofore, the processes of distribution of produce from the farm to the door of the consumer have been slow, faulty and expensive because of the numerous hands through which it ordinarily passes, each one of which exacts a toll, not always in keeping with the service rendered. POTATOES AS FEED FOR LIVESTOCK 361 POTATOES AS FEED FOll LIVESTOCK The possibility of making greater use of potatoes as a feed for livestock should not be overlooked. It is difficult to grasp the fact that German farmers feed nearly twice as many potatoes to their farm animals as the United States produces. Some 40 million hogs are largely grown and fattened on potatoes in Germany. If we are to have a prosperous and stable agriculture, we must see to it that there is no unnecessary waste. Potatoes, M'hen cooked or siloed and fed with grain, make a reasonably cheap and acceptable feed for swine and other farm animals, though cooking is not neces- sary when fed to cattle. Eound and Gore- have develoi)ed a cheap and satisfactory method of converting cull or surplus potatoes into silage. They summar- ize the result of their studies as follows : 1. "The use of 2 to n jter cent of corn meal, mixed with cruslied potatoes, insures an acid fermentation, which converts tlie potiitoes into silage. 2. This work may l)e done upon any scale. If reasonalde care is used, losses should be negligible. 3. The potatoes should first be washed, and then cruslied Ijy passing them through an apple grater, which has been modified by substituting rows of blunt spikes for the grater knives. 4. The fermentation requires a tight receptacle, which may be a barrel, vat, pit or silo, but must retain the potato juice. 5. The upper surface of the crushed potato should first lie covered, to a depth of several inches, with an absor1)ent, fibrous substance such as straw, corn-stalks or leaves; then closely fitted with a wooden cover, weighted down by stones, until the surface of the potatoes is barely covered by juice. The top of the straw and the board cover should be kept dry. 6. Fermentation begins at once. With -the evolution of gas, con- siderable pressure develops, which should be controlled by extra weights. After a few days this pressure disappears. Acid fermentation continues, however, for two or three Aveeks. As in other fermentations, the length of time necessary is directly dependent on the temperature. 7. The resulting potato silage is refreshingly acid in flavor, free from any putrid odors and of aliout the consistency and appearance of the original crushed potato. 8. Potato silage is eaten freely liy cattle, and somewhat less readily at first by hogs, although they soon learn to eat it " In sections where there are no starch or potato-flour factories to utilize the ciills or surplus stock, good agriculture demands that some provision be made to feed them to livestock, and thereby utilize their feed values, thus increasing our dairy and meat j)roducts. 362 INDUSTRIAL USES OF THE POTATO QUESTIONS ON THE TEXT 1. What determines the value of a food crop for industrial purposes? 2. What does a chemical analysis of the potato reveal as to its constituents? 3. What is its most important constituent? 4. In what other crops does starch occur abundantly? 5. What are the chief manufactured products of the potato? (5. From what portion of the potato crop of the United States is starch manufactured ? 7. Describe the successive steps involved in the manufacture of starch. 8. What is the average yield of commercial starch from cull potatoes? D. What are the commercial outlets for all kinds of starches? 10. What are the chief uses made of potato starch? 11. To what e.xtent is potato starch manufactured in the United States? 12. In what states is potato starch most largely manufactured? 13. Which state is of greatest importance and what per cent of the total output is made in this state? 14. What is the usual or normal price paid for potatoes by starch manufacturers? 15. How many starch factories were in operation in the United States in 1904, 1909 and 1914? 16. How did the outpiit of potato starch compare with that of cornstarch during these periods ? 17. About how many bushels of potatoes were required for starch purposes and what per cent of the total crop did it represent? 18. How does this amount compare with that of Germany? 19. What proportion of our crop would 4 per cent of the German crop represent? 20. How extensive are the imports of starch into the United States? 21. How did these imports shift during the war? 22. What economic factors are involved in the manufacture of a constant supply of potato starch? 23. When did the American public first become interested in potato flour? 24. Describe the processes involved in the manufacture of potato flour. 25. Wliat is the diflference between potato flour and potato starch flour? 26. Upon what does the future of the potato flour industry depend? 27. What are the ordinary products manufactured from the potato through the process of dehydration? 28. How is the industry to be regarded in the United States? 29. Describe the processes involved in the manufacture of good, dried, sliced potatoes. 30. Describe the manufacture of dried, riced potatoes. 31. To what extent were dried potato products manufactured during the war? 32. What is the present status of the industry? 33. Of what commercial importance is the potato drying industry in Germany? In the United States? 34. Describe processes involved in the manufacture of potato dextrine. 35. How does potato dextrine compare in value with that of dextrine made from other starches? 36. Of what importance is potato glucose production ? 37. In what country has potato alcohol production become an important commercial industry? 38. What are the needs of the potato industry in the United States? 39. What is the average per capita production in the United States? REFERENCES CITED 363 40. How does the average per capita consumption in the United States compare with that of Germany? 41. What percentage of the total German potato crop is consumed for table purposes? 42. How does the German percentage compare with that of the United States ? 43. How is the balance of the German crop iitilized? 44. How does the large excess of potatoes over and above the needs of the German people for table purposes tend to stabilize the price? 45. What efl'ect does alternate years of high and low production have upon the table consumption of potatoes in this country? 40. What is the solution of the problem of high and low production with its consequent price fluctuations? 47. What is the relation of distribution to crop production? 48. iMong what other lines may we increase potato consumption? 49. Describe the process of making silage out of the potato. EXERCISES SUGGESTED BY THE TEXT 1. Collect a set of samples of potato products and preserve them in glass jars or bottles. 2. Examine potato tissue under a strong microscope. 3. Draw several grains of potato starch showing the layers. 4. Grate a large potato, using a kitchen vegetable grater. Hold the material in a cheesecloth and wash thoroughly in a dish of water to remove the starch. Allow it to settle, remove the water and dry the starch. 5. Weigh the starch from a given weight of potato and determine the percentage of starch. 6. Determine the percentage of water in a potato Ijy weighing, slicing, drying and weighing again. References Cited 1. Kremers, E. IGl/). Agricultural alcohol: Studies of its manufacture in Germany. U. S. Dept. Agr. Bui. 182: 14, Feb., 191;}. 2. Round, L. A., and H. C. Gore. 1916. A preliminary report upon the making of potato silage for cattle food. Proc. Third Ann. Meeting Pot. Ass'n. of Am.: 75-79, 1916. 3. Skinner, R. P. 1914. Utilization of potatoes. U. S. Dept. Commerce Spec. Cons. Rpt. No. 64: 1-44, 1914. PART II CHAPTER XIX THE BOTANY OF THE POTATO The potato is botanically known as Solarium tuberosum, L., and is a member of the Solanacece or nightshade family of plants. The tomato, eggplant and pepper are close relatives of the potato. In discussing the genus Solarium, Baker- claims that it "is one of the largest genera in the vegetable kingdom. About 900 names stand in the botanical books as species, and Benthara and Hooker estimate that probably 700 of these are really distinct. Of these 700 it is only six that grow potatoes at all, and the remainder all maintain their hold in the world, as most plants do, by means of their flowers, fruits and seeds." The six tuber-bearing species, according to Baker's conclusions (p. 504, 505), are: (1) Solanum tuberosum, L. ; (2) 8. Maglia, Schlecht; (3) 8. Commersoni, Dunal; (4) 8. cardiophyllum, Lindley; (5) 8. Jamesii, Torrey; (6) 8. oxycarpum, Schiede. More recent studies by Bitter/ of Bremen, Germany, have re- sulted in a much larger list of tuber-bearing species than is con- tained in Baker's list. An enumeration of Bitter's species, as well as those of others, is not, however, considered pertinent to the present discussion. It is, however, thought desirable to give Baker's descrip- tion {I.e. p. 489), made from the living plant, of a typical specimen grown in the herbaceous ground at Kew Gardens, England: Description. — " Rootstock bearing copious large tubers. Stems stout, erect, flexuose, much branched, one to two feet long, slightly hairy, distinctly winged on the angles. Leaves pseudo-stipulate, a fully developed one about half a foot long, with seven to nine finely pilose, oblong, acute, large leaflets, the side ones stalked and unequally cordate at the base, the one to two lowest pairs much dwarfed, leaving a naked petiole about an inch long, the rhachis furnished with numerous small leaflets, inter- spersed between those of full size. Flowers numerous, arranged in com- pound terminal cymes, with long peduncles; pedicels hairy, articulated about the middle Calyx hairy, one-fourth to one-third inch long, teeth deltoid-cuspidate, as long as, or a little longer than, the campanulate tube. Corolla dark lilac, subrotate, nearly an inch in diameter, pilose externally; segments deltoid, half as long as the tube. Anthers bright orange-yellow, linear-oblong, nearly one-fourth inch long; filaments very short. Berry perfectly globose, smooth, under an inch in diameter. The potato tuber arises as a terminal enlargement or swelling of a thick, and usually rather short, underground stolon. These 364 THE BOTANY OF THE POTATO 365 tuber-bearing stolons arise from what above ground would be the axils of the leaves, on the main stem of the plant, extend more or less horizontally outwards, and sooner or later normally swell up Fig. 199. — Early stage of tuber development. Note special tuber-bearing stolons. at their tips to form tubers (Figs. 199 and 200). In this con- nection, Eeed^ says : "That these structures are stems is shown Ijy their origin and their ana- tomical and morphological structure" Arthur^ describes the potato tuber as follows : "The potato tuber is a thickened stem, having the cells mostly filled with starch as a reserve food for the new plants. The eyes are the promise THE BOTANY OF THE POTATO of the future branches. The skin differs from the surface covering of the rest of the plant by being formed of a layer of delicate cork with its accompanying lentioels, and the fibrous framework, as well as the pith, is continued from the leaf-bearing stems into the tuber with relatively little change. Liquids move from part to part, most readily through the fibrous tissue, and not through the proper pith. This indicates that in Fig. 200. — A more advanced stage uf tuber development than in Fig. 199. cutting seed potatoes, the movements of the nutrient sap in germination have no bearing upon the question of the best form of the pieces, except that they should reach deep enough to include the wood ring." In Baker's technical description of the plant he says that the stem is distinctly winged. This statement was, of course, based on the plant he described and does not necessarily apply to all of PARTS OF A POTATO TUBER 367 our cultivated varieties, as many of them are not winged or if they are, it is very slight. The same explanation should be made re- garding the color of the flowers, which, while constant in any given variety or group of varieties, is not constant with respect to all varieties. It is well known that the color of the flower may vary with the variety, from the delicate creamy-white through all shades of pink, rose-purple, lavender and blue. In fact, many of them are extremely attractive in" color and large in size, especially in seedlings resulting from South American crosses. Parts of a Potato Tuber. — The potato tuber may be anatom- ically divided into four rather distinct parts or zones which are morphologically known as: (1) The envelope or skin; (2) the cortical layer; (3) the external medullary area, and (4) the internal medullary area. The delimitations of 1 and 2 are clearly defined but that of 3 and 4 are not so clearly separable. They are usually defined as follows : 1. The envelope or skin comprises the corky or outer cover- ing of the tuber, corresponding to the bark of an above-ground stem. 2. The cortical layer consists of the peripheral zone immedi- ately beneath the skin. This zone or layer may vary from one- eighth to one-half an inch in thickness. It is denser and less translucent than the external medullary area, from which it is separated by a well-defined line or ring of fibro-vascular bundles. If exposed to light, this part of the tuber quickly turns green, and acquires a distinctly acrid taste due to an accumulation of a poisonous substance, chemically known as solanin. 3. The external medullary area embraces the outer portion of the strictly fleshy part of the tuber. It is generally interpreted as including the denser portion of the medullary area. 4. The internal medullary area includes the Avatery and more translucent central part of the tuber. Langworthy^ states that, according to determinations made in the Department's laboratories, the actual skin of the potato rep- resents about 2.5 per cent of the whole, the cortical layer about 8.5 per cent, leaving 89 per cent for the medullary areas. This difl'ers quite appreciably from the percentages given by Condon and Bussard* as will be noted from the following figures: Envelope or skin 8.79 per cent. Cortical layer .36.19 per cent. External medullary area 34.17 per cent. Internal medullary area 14.96 per cent. 368 THE BOTANY OF THE POTATO From the botanical standpoint, these variations in percentages are of no material consequence to the present discussion. It is, perhaps, permissible, however, to say that from the chemical stand- point the relative proportion of these four parts of the potato is vitally important, as it is materially concerned with its food value. The cortical layer is of especial interest, because it contains, in addition to starch, a higher ])ercentage of mineral matter, soluble carbohydrates and nitrogenous matter, as well as of acid sub- stances, than do the other })arts of the tubers. QUESTIONS ON THE TEXT 1. Under what name is the potato hotanioally known? 2. Is the Solantim group a large one? Name common garden crops of this group. 3. How many, according to Baker, are tuber-bearing? Name them. 4. Does Dr. Bitter concur with Baker in his limitation of tuber-bearing species ? 5. What is the potato morphologically? 6. What can you say regarding the winged stems? 7. Name the four parts of a potato tuber. S. Deseri!)e eacli. EXERCISES ON THE TEXT 1. Compare the flowers of potato, tomato, eggplant or others of the family and note likenesses. 2. Read the floral descriptions in a good botany book and compare with the specimens. 3. Study the morphology of the undergroimd parts of a potato plant and show that underground stems do exist. 4. Preserve some of these underground parts with small tubers in a glass jar. Use two per cent formalin water. 5. Find specimens showing the winged stems and others where the wings are less prominent. 6. Make sections of potato tubers and point out the four parts. 7. Draw and label parts. References Cited 1. Arthur, J. C. 1888. Structure of the potato tuber. Ind. Sta. Bui. If), 1888. 2. Bakkk, J. G. 1884. Review of the tuber-bearing species of Solannm. Jovr. Linn. ISoc. of Bot. (London) 20: 489-507, 1884. .3. Bitter, G. 1912-1914. Solana nova vel minus cognita. Repertoriiim 8p. Nov. Regni Vegetal). 10: 520-565; 11: 1-18, 202-237, 241-200. 349-394, 431-473, 481-491, 5Gl-5(iO; 12: 1-10, 49-90, 136-162, 4.33- 467, 542-555; 13: 88-103, 169-173, 1914. 4. CouDON, H., and L. Bussard. 1897. Recherches sur la pomme de terre alimentaire. Ann. »*?c. Agron. 2nd. ser. 3rd ann. 1: 261, 1897. 5. Lanc.wortiiy. C. F. 1917. Potatoes, sweet potatoes and other starchy roots as food. U. 8. Dept. Agr. Bui. 468: 1-28, Jan., 1917 (seep. 24). 6. Reed, F. 1910. Anatomy of some tubers. Ann. Bot. (London) 24: 537-548, pis. 2, 4 dgiiis. CHAPTER XX ORIGIN AND EARLY HISTORY OF THE POTATO Origin, — For over a century the question of the origin of the potato has occupied the minds of many botanical explorers and nat- uralists. While scientists are agreed that the potato is indigenous to South America, they are divided in tlieir beliefs concerning the ])articular locality in which the wild tuber-bearing species, of whicli it is a descendant, originally occurred. One group of scientists claim C!hili as the original home of the potato, while another group are inclined to regard Peru, or Peru and Bolivia, as the region from which it came. Those who regard Chili as its source appear to be in the majority ; but, to the writer, the evidence seems to ])e in favor of Peru, or possibly of the wliole Andean section of South America, stretching from the northern boundary of Ecuador to tlie southern portion of Peru. Wight's^^ summation of the evidence both for and against its Chilean origin is a comprehensive review of the more important literature on the subject. His conclusions, based on the literature, a critical examination of material in American and Euro])ean her- barias, and a six months' exploration trip througli Chili, Peru, Bolivia and Ecuador, (made for the express purpose of securing first-hand information concerning the existence of the wild form Solamiin tiiberosunt, L. ), are as follows: "Every reported occurrence of wild >S^. tuberosum that I have been able to trace to a specimen, either living or preserved in the herbarium, has proved to be a different species. In fact, so far as the herbarium material is concerned, I have not found in any of the principal European collections, a single specimen of Holanum tuberosum collected in an undoubtedly wild state. After a century and a half of intermittent collect- ing, there is no botanical evidence that the species is now growing in its original indigenous condition anywhere. So far as the number and relationship of the species referred to the section tuberarium are con- cerned, the evidence is in favor of the central Andean region." The central Andean region referred to comprises northern Chili, Peru, Bolivia and Ecuador. Early History. — The first mention of the potato in literature is that found in Cieca's "Chronicles of Peru" published in Seville, Spain, in 1553, Cieca was a young Spanish adventurer who, at the early age of fourteen, sailed with an expedition from Spain 24 369 370 ORIGIN AND EARLY HISTORY to Cartagena, where he landed in January, 1833. In 1838 he joined an expeditionary force that crossed the mountains and advanced up the valley of the Cauca. In 1541 he began to keep a journal wdiicli he continued througliout his soldier's career, which took him southward as far as the mines of Potosi in southern Peru. Among the many interesting data recorded by Cieca in his journal were those pertaining to the agricultural regions, through which he and his soldier companions fought their way southward. In Markham's" English translation of Cieca's Chronicles, the potato is alluded to seven different times in connection with different localities through which he passed. On page 117 he says: "In the Provinces of Chapanchita, Bomba and Popayan. . . .they gather great quantities of potatoes." On page 121: "The districts of Pasto yield but little maize. . . .The country yields much barley, potatoes, etc." Page 131: "In all these villages (Pasto, Funes, Gualmatan and Ipiales), they grow many potatoes." Page 143: "Of provision besides maize, there are two other products which form the principal food of these Indians. One is called potato." Page 174: "In the Province of Santiago de Puerto Vie jo the land is fertile, yielding an abundance of maize, yucas, aji, potatoes and many other roots." Page 234, in speaking of the crops grown in the fertile coast valleys, Cieca says: "They also raise sweet potatoes. .. .besides potatoes, beans and other vegetables." Pages 360-3G1, in speaking of the Callao region, he says of the inhabitants: "Their principal food is potatoes which are like earth nuts.... They dry these potatoes in the sun and keep them from one harvest to the next. After they are dried tliey call these potatoes chufius, and they are highly esteemed and valued among them. They have no water in channels for irrigating the fields, as in many other parts of this kingdom, so that, if the natural supply of water required for the crop fails, they would suffer from famine and want if they had not this store of dried potatoes. ]\Iany Spaniards have enriched themselves and returned prosperous to Spain, 1)y merely taking these chunus to sell at the mines of Potosi." Cieca describes the climate of the Callao region as being "so cold that there is no maize, nor any kind of tree; and the land is too sterile to yield any of the fruits which grow in other parts." From the above mention of the potato it is quite evident that it was a common article of food, and rather generally cultivated throughout a considerable portion of the region transversed by Cieca; or from the southern portion of what is now known as Colombia, to the region of Lake Titicaca or beyond. That Cieca and later writers recognized that the potato, or "papas" as it was universally called ])y the Indians, had long been under cultivation in that region is quite evident from their writings. It is not. strange, therefore, that after a lapse of nearly four centuries the evidences of its origin should be so obscured as to make it impossible for any person, no matter liow well versed in the origin of our INTRODUCTION INTO EUROPE 371 cultivated i:)laiits he may be, to determine definitely what the original wild form may have been. There is no certainty that the plant, to which the name Solanum {uherosum, L. was given, was a pure wild species. The reason for making such a statement is due to the fact that the plants originally studied and described by both Bauhin- and Clusius^ did not represent a pure wild species because, according to both of these botanists, there were both purple and white flowering plants among the seedlings grown from them. This is directly opposed to the behavior of seedlings grown from any of the wild species studied in the past fifteen years. In not a single instance has it been found that such seedlings bore either flowers or tubers that were sensibly different, either in color or in form, from that of the parental plant. These observations were made on the following species of Solanums: cardiopliyllum, dcmis- sum, verrucosum, utile, polyademium and several unidentified ones from South America. While the above observation does not neces- sarily prove the statement made, as to the unlikelihood of the original forms studied being simon-pure with respect to certain unit characters, as, for example, color of flowers and tubers, it does afford conclusive evidence that at some time during the centuries preceding those in which the Spaniards found the potato occupying an important place as an article of food in the Andean region of South America, two or more species must have hybridized ; or else we must accept the De Vriesian theory, and assume that mutants appeared in the original wild species. It is known that, at the time of the conquest of Peru, more than one variety of potato was l)eing grown by the natives ; and that then, as in many sections of South America today, the potato was very largely reproduced from true seed, rather than from the tubers. It is the exception rather than the rule today, to find the Indian in the Andean region growing but one variety in his potato plot; the chances are strongly in favor of his having a dozen or more different varieties (seedlings) intermingled with one another. Introduction into Europe. — Its introduction into Euroi)e is supposed to have occurred shortly after the Spanish conquest of Peru, or about the middle of the sixteenth century. That it may have been carried to Europe at a somewhat earlier date is, of course, possible, but hardly probable, since it would have attracted the notice of some of the European botanists of that period. It is thought to have been carried into Italy from Spain, and from Italy into central Europe. 372 ORIGIN x\xND EARLY HISTORY In the meantime, the potato is supposed to have found its way into the Old World from another and entirely distinct source, if we are to believe the commonly accej)ted notion that, in 1586, it Avas brought to England in one of Sir Walter Raleigh's ships, on its return from the colony which Sir Walter established in Virginia in 1584. Upon this introduction, or theory of it, Wight (I.e. p. 39) says: "The idea that the potato Avas introduced from Vir^fiiiia into Eujflaiid. is. however, so prevalent in literature that it should have some consideration, even thou<;h the claim is not made that the potato was native to Vir<>inia. Few, in fact, have believed that it was cultivated by the Indians previous to the era of European exploration and settlement; and no evidence has ever been brought forward, so far as I am aware, in support of such a contention. The conclusion in regard to its introduction from Virginia rests solely on the assumption that the root (called by the Indian Openauk) , described by Thomas Ilariot in A irief and true report of the new found land of Virginia, first printed in London in 158S, is the potato; and is also the plant described by Gerard in his IlerbaU, issued in 1598. Hariot says: 'These roots are found in moist and marshy grounds, growing many together i!i ropes as though they were fastened to a string.' He states that they gi'ew naturally or wild, which would be improbable if they were potatoes introduced after the discovery. The description also applies better to Apios tuberosa, the ground nut, than it does to the potato. Furthermore, the Indians would scarcely have had a distinctive name for a plant so recently introduced. "We may assume, from the evidence at hand as to the improbability of the potato being known, and still less cultivated in Virginia at that time, that if Raleigh's vessels in charge of Sir Francis Drake did bring the potato to England on the date mentioned, they must have secured it from some South American trading vessel, or at a point other than Virginia." The first published description ol' tlie potato found is by Bauhin.- While it was based on rather scanty material, it is sufficiently comprehensive and accurate as to leave no doubt in the reader's mind as to its being the potato. In describing the plant Bauhin says : "The stem is in the form of a stalk about one and one-half to two feet in length; fruit in the sliape of a golden apple, nearly round stem green, somewhat branched, nevertheless it sometimes reaches the height of a man Leaves about the length of the hand, rough on the under side with pale hair. Much divided into si.\, eight or more or less parts; like single leaves, to the number of which an odd one is always added; round to oblong, simple, arranged opposite and there are usually two, six or more small leaves interspersed along the leaf stalk. "The branches are usually divided into two stalks, each of which bears many flowers, some closed and three or four open, ranging from blue to purplish, spreading out into five points which somewhat greenish-yellow lines traverse and divide; in the centre there are usually bunched four reddish stamens, as in Malum insanuni. INTRODUCTION INTO EUROPE 373 "The flowers are succeeded by single round fruit?, hanging on long stems, like a cluster, as in Holanum vulgare, but far larger; for some of tliem equal a nut (probably a walnut) in size; some of them indeed grow no larger than a filbert, all nevertheless striped with equal lines, like the Malum aureum, which range from green to blackish and, when mature, Fig. 201.— Bauhin in Prodrumus Theniri Bulanici, 1020. to a dark red (probably a dark purplish-black). In these the seed is small, flat and round, somewhat swarthy. "The root is round, but not circular, of a swarthy or dark red color; it is taken up from the earth in the winter time, and is returned to the earth in the spring. "At the base of the stem, at the head of the main root, long fibrous roots are spread out, on some of which small, round roots are borne (tul)ers). "We name this Holnnum because of a certain form of its leaves and of the fruit, which is like Malum aureum; then, of the flowers, which are like Malum insanum ; then, of its seed, which corresponds to the Solani; and, finally, on account of the unpleasant odor of it, common to the Solani." In giving his source of information Bauhin says : "The seed was sent under the name of pappas of the Spaniards, and originally of the Indians, which grew easily in our garden almost like a leafy shrub, as in the garden of Dr. Martinius Chmielecius, who had one with a white blossom. On account of our long-standing friendship, Dr. 374 ORIGIN AND EARLY HISTORY Laurentius Scholtzius, a physician, sent me a drawing of a plant that he had grown in his garden, sketched in colors, but without fruit, and the root appendages." * (Fig. 201). In this publication Bauhin names the potato Solanu7n tuber- osum, but in Frodromus Theatri Botanici, published in 1620, he changes the name to S. tuberosum esculentum. According to Mitchell/ Gerard in his 1596 catalogue applied the name of "Papas orbiculatus" to the potato. He evidently Fig. 202. — Rpproduction from Gerard's Herball, 1697. changed his mind when he published his Ilerball in 1597 because, as will be seen from the reproduction (Fig. 202), he renamed it Batata virginiana sine Virqinanorum et P apus. — Potatoes of Vir- • Translated from the Latin by Mrs. Grace Graham Brannin. INTRODUCTION INTO EUROPE 375 ginia. In his 1599 catalogue he again refers to it as Papas orbicu- latus. Wight (I.e. p. 40) in commenting on these inconsisten- cies says : "It is curious, if Gerard had the plant described by Hariot, that he did not use his name ( Openauk ) instead of a word which is not known to liave occurred in the Indian language within the present border of the United States or Canada. The question of how Gerard came by the word 'papas' may be settled with reasonable certainty, for he says : 'It groweth naturally in America where it was first discovered, as reporteth C. Clusius. . . .It is doubtful if Clusius would have reported anything concerning the potato before he had received tubers, which was in 1588, two years after Harlot's return from America; yet Gerard says: 'since which time (referring to the statement of Clusius ) he had received roots from Virginia,' and this would indicate that he must have received roots from some other voyage. The figure in the Herhall is in two parts, and it may be doubted if the tubers figured are potatoes, at least this part of the figure, for some reason, is changed in Johnson's edition of the Herhall in 1636." If judged literally, one might well question whether Gerard's illustration of the root and tuher development of the potato was really made from the potato. If, on the other hand, we regard it as a purely diagrammatic drawing, we may accept it for what it is intended to convey, rather than what it actually does convey to the mind. The stem, leaves, flowers and fruits are sufficiently accurate as to leave no question in one's mind as to its identity. In 1601, Clusius j^ublished a description of the potato in his Rariorum Plantarum Hisioria, Chap. LII, p. LXXIX, in which he calls it Papas Peruanorum. Clusius begins his description by saying: "There is an edible root of a new plant, which but a few years ago Avas not known in Europe It springs at first from a bulb, which, with us, starts into growth about April, not later; within a few days after planting it puts forth leaves of a dark purplish color, hairy, which, presently unfolding, show a green color; 5, 7 or more leaflets on the same stem, not very different from the radish, always of an odd number, some smaller leaves being interspersed, and the odd one always occupying the extreme tip of the petiole. The stem is of the thickness of the thumb, angular, and covered with down. From the axils of the petioles coarse stalks appear, angular pedicels, bearing 10 to 12 or more flo\\'ers aI)oiit an inch or more across, angular, consisting of one piece, but so folded that there appear to be five separate leaves, of a whitish-purple on the outside, inside purplish, with five green rays appearing from the centre like a star, with yellow stamens gathered together in the centre, and a prominent greenish style. After the flowers, which bear an odor resembling the odor of the flowers of the linden, roimdish apples appear, not much different from the fruit of the mandrake, only smaller, green at first, white at maturity; full of juicy pulp which contain many flat seeds scarcely larger than the seeds of the fig." In describing the tuber development he says: 376 ORIGIN AND EARLY HISTORY -> V Fig. 203. — Reproduction of drawing of potato stem sent to Clusius by Philip de Sivey in 15S8. "When, in the month of November, the plant is dug after the first frosts, there are discovered tubers of various sizes. These are uneven, recognized by certain marks whence, the following year, shoots will start forth. I remember, also, that there were collected more than 50 tubers INTRODUCTION INTO EUROPE 377 from one single plant, some so large that they weigh an ounce or even two, the outside skin reddish or approaching a purple color, some small, as though not yet mature; they have a whitish skin which is very tender in all the tubers, but the flesh itself is firm and white. "From the tubers alone therefore, we must expect the preservation of the genus, and from the seed, the daughter plants of which, in the same year, bear blossoms, but of a diff'erent color from the mother plant. So I have learned from others, though I have never tried the experiment Fig. 204. — Reproduction of Clusius dra\ from the living potato plant, 1601. myself. True it is that my friend Joannes Hogeladius described plants to me produced from seed which I sent him, Avhich produced white blossoms altogether. I received the first authentic information about this plant from Phillipus de Sivcy, Dn. de Walhain and Prefect of the City of Mons in Hannonia. of the Belgians, who sent two tubers of it, with its fruit, to me at Vienna, Austria, at the beginning of the year 1-187. and in the following ,year, a drawing of a branch with a flower, ( Fig. 203 ) . He wrote that he had received it the preceding year from a certain employee of the Pontifical Legation in Belgium. Later Jacobus Garerus, Jr., sent me a Frankfort drawing of a whole stalk, Avith roots. Indeed, I have much desired to exhibit the whole plant here, but I have taken pains to portray it in two drawings from the living plant — one representing flowers and fruit, the other roots and tubers clinging to their own fibres, (Fig. 204). 378 ORIGIN AND EARLY HISTORY "The Italians do not know where they were first produced. Certain it is, however, that they were obtained either from Spain or from America. It is a great wonder to me that, when it was so common and frequent in Italian settlements (so they say), that they feast upon these tubers, cooked with flesh of mutton, in the same manner as upon turnip and carrots, they give themselves the advantage of such nourishment, and allow the news of the plant to reach us in such an off-hand way. Now, indeed, in many gardens of Germany it is quite common because it is very fruitful." ** Authorities Differ. — It is apparent to the reader that there are some inconsistencies in the description of the potato by both Bauhin and Clusius. Take for example Bauhin's description of the fruits, which he says are dark red when mature. In many of the varieties from South America which have come under our observation, the mature fruits are a dark purplish-black or dark bluish-green black, whereas in all varieties that are classified under groups 1 to 12 in Chapter XII they are a light lemon-yellow color when mature. In view of this fact, we may accept Bauhin's description of the color as not entirely inaccurate. It requires some imagination on the other hand to accept Clusius's statement that the odor of the potato flower resembles that of the linden. His description of the color of the mature fruits would indicate that the variety he had was different from that of Bauhin's. The accuracy of obser- vation of Clusius is well indicated in his description of the color of the tubers in which he says "some small, as though not yet mature, they have a whitish skin." This observation has been repeatedly verified in studying a number of tuber-bearing species of Solatium from Mexico. The immature tubers very frequently do not show color, whereas when they mature, several species have always developed a purplish color. Development of Potato Culture in Europe. — While we have little definite knowledge as to how extensively the potato was culti- vated prior to the seventeenth century, we can safely assume that it had not yet emerged from the curiosity or novelty stage in its development as a staple food plant, although Clusius (I.e. p. 1601) says that it is reported to be more or less commonly grown in Italy, and further remarks that, because of its fruitfulness, it is quite commonly grown in many gardens of Germany. Despite these statements of Clusiu s, the fact remains that the potato was •♦Translated from the Latin by Mrs. Grace Graham Brannin. POTATO DEVELOPMENT IN PRUSSIA 379 little grown in Europe before the latter part of the seventeenth century, and, in fact, did not become of great commercial impor- tance until the latter half of the eighteenth century. Development in Great Britain. — Phillips^'^ says : "The potato first became an object of national importance in 1662-3 as appears by the record of a meeting of the Royal Society held March 18 in that year; when a letter was read. .. .recommending the planting of potatoes in all parts of the kingdom to prevent famine Notwith- standing, it Was not till within the last twenty years (1802) that they were used as a substitute for corn bread (wheat bread) in England, when the apprehension of a scarcity induced all prudent families to adopt the use of potatoes at their dinner tables, in lieu of bread or puddings." Miller^ in 1731 mentions two varieties or sorts, the red and the white which, he says, were both indifferently cultivated in England at that time. Krichauff^ says that up to 1784 potatoes were chiefly grown in the gardens of peers and rich men; and that in 179G Essex County, England, grew about 1,700 acres for the London market. In Scotland, he says, that prior to 1760 they were mostly grown in gardens ; after that date they were more generally grown. Loudon" makes a very similar statement in 1830, in which he says that the cultivation of potatoes, even in gardens, was little under- stood prior to 1740; and that it was about twenty years later before they were much grown as a field crop. He further mentions the fact that the famous nursery firm of London and Wise did not consider the potato worthy of notice in their Complete Gardener, published in 1719, He also observes that, in addition to the acre- age grown in Essex County in 1796, many fields could be noted in other counties bordering on the capital, (London); that many shiploads were annually imported from a distance; and that in 1830, the potato was more or less an object of field culture in every county in England. The development of potato culture in Ireland was contempo- raneous with that of England ; in fact, the potato, on account of its yield per acre and relative cheapness, became a vital source of food supply to the inhabitants of Ireland at a much earlier date than in England, Indeed, if we may judge acreage as a criterion of the importance of a crop, Ireland's preference for the potato is well indicated, as in 1917 she grew 709,000 acres of potatoes as against England's 473,000 and Scotland's 148,000. Potato Development in Prussia. — The following incident, recorded by Krichauff {I.e.), casts a rather interesting sidelight on 380 ORIGIN AND EARLY HISTORY the attitude of the Prussian j)easants and the people in general toward the use of the potato as a food plant. The incident cited is as follows: "Frederick the Great of Prussia was more successful than his father ill introducing the cultivation of potatoes into Pomerania and elsewhere; hut he liad recourse to his soldiery, who had to force the farmers to plant them. If it had not been for the jjreat famine in Germany in 1771-72, the f^reat benefit of the cultivation of potatoes would not have been so gen- erally acknowledged." Potato Development in France. — Potato development in France was somewhat slower than in Great Britain, Germany, Austria or the adjoining countries. Krichauff (I.e.) says: "In 1771 a high prize was offered by the Academy of Besancon for the discovery of a new food which would fill the place of cereals in case of a famine. Parmentier showed his potatoes, and Louis XVI gave him 50 morgen of land (a morgen equals 2.11 acres) to plant them on. When showing the first flowers of his potatoes the king used them as a buttonhole bouquet; Queen Marie Antoinette had them in the evening in her hair, and at once princes, dukes and high functionaries M-ent to Parmentier to obtain such flowers. All Paris talked of nothing but potatoes and the cultivator of them. The king said: 'P" ranee will thank you some time hence, because you have found bread for the poor.' And France has not forgotten Parmentier, for I saw for myself in 1882, potatoes growing on his grave in the grand cemetery of Paris, the PCre Lachaise, and I was assured that they were planted there every year so that his services might never be forgotten by Frenchmen " Vilmorin" admits that the culture of the potato was well established in Germany when it was still in an embryonic stage in France, except in the Ardennes region. He further says : "During the Avhole of the seventeenth century, and in all probability the greater part of the eighteenth, the potato of Clusius seems to have been solely cultivated, and did not give but a single variety with white flowers. But in 1777 Engel catalogued 40 varieties. Parmentier in 1786 counted 11 and in 1809, 12, saying, elsewhere, that other authors cited more than (iO varieties. The Society National d'Agriculture de France (then Imperial) gathered together in 1814 and 1815 a collection of 115 to 120 varieties, which was confided to my great-great-grandfather and which was the beginning of a collection that I still possess." Potato Development in Sweden. — Tn an unsigned article appearing in the page devoted to "short notes from papers" of The, Gentleman's Mag. vol. 34, p. 579, 1764, the following mention is made of potato culture in Sweden : "It seems strange to us, but it seems it is a fact, that the Swedes have but just discovered the culture of potatoes, notwithstanding the indefatigable industry of the great Linnaeus. A royal edict, however, is now issued to encourage their cultivation." POTATO DEVELOPMENT IN AMERICA 381 Potato Development in India. — The following remarks by Johnson* are illuminating in that they reveal very much the same conditions as in Euroi)e : "At the horticultural show in Calcutta during 1842, I saw potatoes exhibited which would not have shamed the potato growers of Lancashire, (England), if mistaken for their produce. These were grown in the immediate vicinity of the city, but in the hills of Chirra Pongie, though not far distant, the potatoes are grown still finer. They were an object of cultivation there during the Governor-Generalship of Warren Hastings (1772-1785), and alluding to that period a writer says: "Three score years ago, a basket of potatoes, weighing about a dozen pounds, was occasionally sent, as opportunity offered, by Warren Hastings to the Governor of ■Bombay, and was considered an acceptable present. On reception, the members of the council were invited to dine with the Governor to partake of the rare vegetable.' " Potato Development in America. — If we turn to America, we find that the ])otato was i)robal)ly unknown to American agri- I'ulture in either the sixteenth or seventeenth century and that it was not until the early part of the eighteenth century that they were first introduced into this country. Watson/- in his Annals of Philadelphid, published the following paragraph regarding potatoes : "This excellent vegetable was very slow of reception among us. It was first introduced from Ireland in 1719, by a colony of Presbyterian Irish, settled at Londonderry, in New Hampshire. They were so slow in its use in New England that, as late as 1740, it was still a practice with masters to stipulate with some apprentices that they should not be obliged to use them. The prejudice was pretty general against them that thev would sliorten mens' lives and make them unhealthy, and it was only wlien some people of the better sort chose to eat them as a palatable dish that the mass of the people were supposed to give them countenance." On page 486 of the same volume Watson further says : "As late as my mother's childhood potatoes were then in much less esteem than now. The earliest potatoes, like the originals now discovered from South America, were very small, compared with the improved stock. They were small, bright-yellow ones, called kidney potatoes, and probably about seventy-tive years ago, they then first introduced a larger kind, more like the present in use, which were called in New England the Bilboa! In Pennsylvania the same kinds of potatoes were called Spanish potatoes." Bailey-" makes the following statement: "Pro])ably the potato was served as an exotic rarity at a Harvard installation in 1707, but the tuber was not brought into cultivation in New England till the arrival of the Presbyterian immigrants from Ireland in 1718." He further states that "only two Varieties were listed in 1771, yet by the end of the eighteenth century they were numerous." 382 ORIGIN AND EARLY HISTORY QUESTIONS ON THE TEXT 1. What is the common belief regarding the origin of our cultivated potato? 2. When and where was the potato first mentioned in literature? 3. Where was tlie potato usually grown in those days? 4. What can you say of it as a food plant at that time? 5. How was it preserved for future use by the natives? 6. How does the evidence at hand justify an acceptance of the common belief that the present cultivated varieties of the potato are the direct descendants of the wild species Solanum tuberosum, L. ? 7. When was the potato first introduced into Europe? 8. What does Wight say about its introduction from Virginia into England ? 1). In what publication was the potato first described? What did' Bauhin name it? 10. What are the inconsistencies noted in Gerard's description of the potato in his Hcrball in 1597 ? 11. When and where did Clusius publish his description of the potato? What did he name it? 12. What does he say about the tubers? 13. Did the potato at once become popular in Europe? If not, give reasons. 14. Give brief account of its development in Great Britain. 15. Why did the potato become popular in Ireland before it did in England or on the Continent? 16. How was the potato popularized in Prussia? 17. How did potato development in France compare with that in Great Britain and other European countries? 18. What does Krichauff say about Parmentier's part in popularizing the potato in France? 19. What does Vilmorin say about the lack of popularity of the potato in his country? 20. Compare the early culture of the potato in Sweden with that in other European countries. 21. What about potato development in India? 22. When was the potato first introduced into America, and where first grown? EXERCISES AND QUESTIONS SUGGESTED BY THE TEXT 1. Collect flowers of several varieties of potatoes in different stages. What variation in color do you find? 2. Compare young tubers with mature ones of the same variety. What variation in color do you find? 3. In harvesting potatoes, note the attachment of potatoes to their stems. What likeness do you find, if any, to their being "attached in chains"? References Cited 1. Bailfa-, L. H. 1912. Potato history. Cycl. Agr. 2: 520, 1912. 2. Bauiiin, Caspar. 1596. Phytopinax. 1596: 301-302. 3. Clusius, C. 1601. Rariorum plantarum : 79, Chap. LII, 1601. 4. Johnson, G. W. 1847. The potato, its culture, uses and history. The Gard. Mo. 1: 19, London, 1847. REFERENCES CITED 383 5. Kbichauff, T. E. H. W. 1895-96. The tercentenary of the introduc- tion of the potato into England. Jour. Roy. Hort. 8oc. 19: 225, 18!)5-9C. (J. LouuoN, J. C. 1830. Encycl. of Gardening, 2nd. od: 624, London, 1830. 7. Markiiam, C. 1864. The travels of Pedro di Cieza de Leon. First part of his chronicles of Peru (Transl. of.) Ilakhtyt. Soc, London, 33: 1-438, 1864. 8. Miller, P. 1731. Gardeners' and Botanists' Diet. 1 : 1731, not paged. 9. Mitchell, W. S. 1886. The origin of the potato. Gard. Chron. n. ser. 5, 19: 303, 1910. 10. Phillips, H. 1822. Histori/ of Cultivated Tegetahles. 2: 87, London, ser. 25: 487, 553, 585, 1886. 11. ViLMORiN. Ph. de. 1910. Pommes de terre. J'ev. Gen. Aaron., n. 1822. 12. Watson, J. F. 1844. Annals of Philadelphia. 2: 420, 1844. 13. Wight, W. F. 1917. Origin, introduction and primitive culture of the potato. Proc. Third Atin. Meeting of the Pot. Ass'n. of Am., Nineteen Sixteen: 35-52, 1917. CHAPTER XXI POTATO BREEDING AND SELECTION To the uninitiated, the subject of plant breeding seems to be surrounded with much mystery. This is probably largely due to the fact that the reproductive organs of plants and the functions performed by them are relatively little understood by the average person, but when once familiar with these processes, plant l^reeding is no more mysterious than animal breeding, in fact the same general laws of reproduction apply to both. Breeding and Selection Defined. — Before proceeding further with the discussion of breeding and selection, as related to the potato, it seems desirable to briefly define the use and the application of these two terms in the present work. Breeding, as here em- ployed, refers strictly to sexual reproduction. Selection refers to the isolation of any desirable variation in a variety from that of the normal, and its ])erpetuation by asexual ])ropa;gation. Limitations of Breeding and Selection. — Broadly speaking, the limitations of potato breeding are those found within the con- fines of the tuber-bearing species of Solanums, but for the most part it may be regarded as being confined to the varieties occurring Avithin the species to which the potato is assumed to belong. The breeder has, therefore, within his power the possibility of crossing two varieties, each of which may have certain desirable qualities not possessed by the other, with the view of combining them in some of the resulting offs])ring. The improvement of the potato by selection is limited to the natural variations occurring within the individual variety itself. As not all such variations are heritable, one cannot always be certain that the mere selection of a variant means progress until it is thoroughly tested. The selectionist, therefore, has a much narrower field than that of the breeder. Nineteenth Century Potato-breeding Achievements. — Lit- tle, if any, real ])rogress was made in jiotato Ijrcediiig ])rior to 1850, either in America or in Europe. From this period on, however, ra])id strides were made in the development and improvement of commercial varieties of potatoes. During this period, the chief consideration in the minds of American potato breeders, aside from 384 THE WORK OF GOODRICH 385 those of Goodrich, seemed to be that of attractive appearance, table quality and })roduetivenes,s. European breeders, on the other hand, paid quite as much attention to disease resistance and starch content as to the other factors mentioned. American Potato Breeders and Their Accomplishments. — To attempt an enumeration of all American potato breeders wlio have had a part in the improvement of the potato during the last half of the nineteenth century is neither feasible nor desirable. But, in order to intelligently trace the progress made, from the time of Goodrich to that of Carman and others, the following list of names is presented as worthy of mention : Goodrich, Bresee, Brownell, Pringle, Eand, Gleason, Heffron, Burbank, Alexander, Reese, Coy, Carman, Craine, Bovee, Safford and Van Ornam. The Work of Goodrich. — The severe epidemic of late blight that swept over this country and Europe during the years 1843 to 1847, and reached its climax in Europe in 1845, causing a wide- spread famine in Ireland, led the Eev. Chauncey Goodrich of Utica, New York, to conceive the idea that the potato, as a result of long continued asexual propagation, had become so weakened in vigor as to be no longer able to successfully resist the attack of disease. He believed that it could only be rejuvenated through sexual reproduction, and began to make his plans for the growing of seedling potatoes, with the idea of developing more vigorous and productive varieties that would be able to very largely resist disease. Through the kindness of the American consul at Panama, Goodrich, in 1851,^- received a small quantity of South American potatoes for breeding purposes. Among this lot was a variety which, from its rough, pur])le skin and its supposed place of origin, he descrip- tively named the Eough Purple Chili. From naturally fertilized seed balls of this variety, produced in 1852, he grew some seedlings in 1853; and from this lot one was selected as worthy of propa- gation. This seedling was introduced in 1857, under the name of Garnet Chili. In speaking of his work Goodrich says: "From the beginning of 1849 to the close of 1854 I originated about 5,400 varieties .... I have but 33 sorts left, many of which I shall doul)tles3 reject in a year or two. The 3,000 new sorts, originated in 1855 and 1856, promise better, but even among them the proportion of truly valuable ones will in the end doubtless be small." Goodrich's statements regarding the relatively few desirable seedlings that are likely to be obtained by the plant breeder indicates a careful and conscientious rejection of all inferior plants, and a 25 386 POTATO BREEDING AND SELECTION firm resolve not to offer to the trade any unmeritorious varieties. That he had a clear notion of the problem before him is evidenced by his summation of what he considered were the important traits which should be included in a valualjle variety of potatoes. These are as follows: (1) Good shape; (2) white flesh; (3) hardiness; (4) freedom of growth; (5) resistance of dry weather; (6) fine flavor; (7) early maturity. Not only does he mention these attri- butes of a good variety but he also indulges in a discussion of varieties having the right shape and those that did not. He further shows his familiarity with the behavior of varieties, by citing those possessing what he terms good bases from which to grow a large proportion of seedlings having shapely tubers. For example, he mentions the Eough Purple Chili as a bad base to use for shape, but a good one for color of flesh and hardiness. So far as known, Goodrich did not do any artificial crossing; all of his seedlings being produced from naturally fertilized seed balls. While in this respect he failed to perform the highest type of plant breeding, his work, nevertheless, impresses one as having been carefully conducted. The varieties that he originated were the Calico, Cuzco, Early Goodrich, Garnet Chili and several others. Of these, the Garnet Chili is still being groA\m as a com- mercial variety in some localities. The importance of Goodrich's work lies not so much in what he himself originated, but rather in the varieties produced by others from his Garnet Chili seedling. In a remarkable tribute to Goodrich, Henry Ward Beecher says^ : "There are few instances on record of zeal so interested, chiefly in two respects. First, in that he would not permit himself to be imposed upon in the judgment which he placed upon the merits of his seedlings; and, secondly, in that he worked out his benevolent labors to the end of his life, without turning his industry to his own profit. He was so busy with his experiments that he had no time to make money" He was a prolific writer, and something like 130 articles from his pen were published in the horticultural and agricultural journals and reports of that period. There can be no question as to the tre- mendous impetus his work and his writings imparted to those who later followed in his footsteps. Work of Albert Bresee. — The next important contribution to the list of potato varieties in America was the Early Rose. This variety was originated in 1861 by Albert Bresee, of Hubbardson, Vermont, from a naturally fertilized seed ball of Garnet Chili, THE WORK OF C. G. PRINGLE 387 and was introduced in a limited way in 1867. The Early Rose may be regarded as the first really promising commercial variety produced in America. It may also be regarded as the foundation stock, from which emanated many of our present day varieties. Bresee also originated King-of-the-Earlies, Peerless and Prolific. The work of C. G. Pringle of Charlotte, Vermont, will always stand forth in the minds of American potato breeders as representing the first careful effort to cross potato varieties, with the object of combining in the resultant offspring certain desirable characters of the parent plants. Pringle was a close observer of nature, a keen student and a good botanist, and he early acquired such skill in the technic of crossing, that we find him in the early seventies contracting with a leading seedsman of New York City to produce hybridized potato seed at $1,000 per pound. Considerable seed was produced at this price and, through the seedsman, was widely disseminated. There is every reason to believe that Priugle's hybridized seed produced many varieties for which the hybridizer never received the credit. His varietal contributions were the Alpha, Adirondack, Rubicund, Ruby and Snowflake. The latter variety is still rememl)ered for its high table quality, but on account of a weak habit of growth and comparative unproductiveness, it has practically gone out of cultivation, at least in a commercial way. The other varieties mentioned were relatively short-lived. Unfortuiiately for plant breeding, Pringle abandoned this field of endeavor just when his productive powers were at their zenith. He became a botanical collector and explorer, in which pursuit he was so successful as to earn the title of "Prince of collectors." In 1876 Robert Fenn, one of England's famous potato breeders published under the caption of "Loohlng Bacl-"° some very inter- esting correspondence between himself and Pringle relative to potato breeding. The following quotation from Pringle's letter under date of January 5, 1876, indicates how thoroughly imbued he was with the subject of potato breeding : "Twenty years ago there was little disparity, as I suppose, between English and American potatoes. The majority of the varieties which we now employ, or certainly those Avhich are grown most extensively, have originated since that time, and have descended from semi-domesticated varieties from South America. Hybridization of species has been one of my aims Besides the original species from the Andes, Solanum tuberosum, I cultivated one, very distinct, from our western territory of New Mexico, 388 POTATO BREEDING AND SELECTION N. Fendleri. As yet, all my pains taken to impregnate it with pollen of the cultivated species has proved unavailing, though partially developed fruits have followed my operations, only to fall away, however, before maturity. When I learn the conditions which the plant requires, and more fully meet them, I shall succeed, doubtless. Peru can furnish still another species, ;S'. Montanum (vide Bot. Mag.) and I am very anxious to secure it." This glimpse of Pringle's work serves to show the thoroughness with which he attacked the potato-l)reeding problems of his day; and one can hardly refrain from indulging in retrospect as to what he might have accomplished had he continued his breeding work. The work of C. W. Brownell of Essex, Vermont, thougli not of as high an order as that of Pringle, extended over a some- what longer period and his introductions are more numerous. The best known varieties are Beauty, Best, Centennial, Early Telephone, Eureka, Superior, Winner and Vermont Beauty (Beauty of Ver- mont). So far as known, Brownell did not make any arti- ficial crosses. Albert Rand of Shelburne, and later of Bristol, Vermont, came more nearly following the same line of breeding as that of Pringle. His ])roductions were Chami)ion, Delaware, Matchless, Improved Peachblow and Silver Skin. O. H. Alexander of Charlotte, Vermont, was a seedsman as well as a plant breeder, and it is a little difficult to determine whether some of his introductions were of his own origination or not. So far as known, he did not cross-pollinate potato blossoms. The seedlings that he originated were either grown from naturally fer- tilized seed balls or from hybridized seed produced by others. His introductions were rather numerous and one of them, at least, is extensively grown. The list is as follows : Charles Downing, Dakota Eed, Everitt, Garfield, Green Mountain, Eeliance, Trophy, White Mountain. Of this list, the Green Mountain is by far the most important, as it and its prototypes are among the most widely grown varieties in the northeastern United States. The productions of Gleason and Heffron were neither numer- ous nor important. The former originated the Willard, and the latter the Chicago Market and Climax. Heffron was closely associated with Goodrich toward the close of the latter's life and assisted in introducing some of his seedlings. Luther Burbank's claim to notice, in connection with potato- breeding work of this period, lies in the fact that he was fortunate enough to produce a seedling, named after himself, which became THE WORK OF E. S. CARMAN 389 widely known and is still extensively grown in some sections, particularly in California. The story of the origin of the Burbank Seedling is not indicative of any particular effort on Burbank's part. It is simply a story of the discovery of a naturally fertilized seed ball on an Early Eose plant in his mother's garden at Lan- caster, Massachusetts, in 1873; its subsequent loss and re-discovery on the ground beneath the plant; the growing of 23 seedling plants from this berry ; and the selection of the most promising one which, three years later, 1876, was introduced by Gregory of Marblehead, Massachusetts, under the name of Burbank's Seedling. Contrast this record with that of Goodrich, who grew about 12,000 seedlings extending over a period of about 15 years, and out of all this number failed to produce any that brought him as much lasting fame as did Burbank's Seedling. This simply serves to illustrate a point too frequently lost sight of by the plant breeder, and that is, that those who follow the pion- eer usually reap the richest reward. Bresee produced an Early Eose from Goodrich's Garnet Chili, and Burbank produced his seedling from the Early Eose. In like manner, iVlfred Eeese, in 1871, obtained the Early Ohio from a naturally fertilized seed ball of the Early Eose, a variety that is still extensively grown in the Eed Eiver Valley in Minnesota and North Dakota, in the Kaw Valley in Kansas, and many other localities in the central and western states. Coy's Productions. — E. L, Coy of Hebron, New York, obtained the Early Beauty of Hebron in the early seventies from a naturally fertilized seed ball of the Garnet Chili. This variety was intro- duced in 1878, and for a considerable period was rather extensively grown. It was a heavy producer of fair quality potatoes, but both vine and tuber were extremely susceptible to late blight. At the present time it is little cultivated. Coy was also the originator of the following varieties : Late Beauty of Hebron, Early Puritan, Empire State, Late Eose, Noroton Beauty, Thorburn, Vaughan and White Elephant. Thus, within a comparatively few years, there was developed from the Garnet Chili, and its daughter the Early Eose, several varieties that are still extensively grown, and from which many others have sprung to enrich our agriculture. The work of E. S. Carman, former editor of The Rural Netv Yorker, is of extreme interest to the plant breeder in that lie 390 POTATO BREEDING AND SELECTION introduced an entirely different strain of seedling potatoes into our agriculture. So far as we are able to judge, Carman's varieties do not possess the same blood as do those which have sprung from the Garnet Chili or the Jersey Peachblow. Unfortunately, Carman did not keep careful records of his work, and the exact parentage of his seedlings is not known. He admits that he failed to make any crosses between the varieties in his collection, and, according to his own account, even failed in the earlier years of his work to find any naturall}' fertilized seed balls. This lack of success in securing seeds led him to advertise widely in The Rural New Yorl'ei^ for potato seed balls. In response to this appeal, some seed was received from Euroj)e, and from these he produced seedlings that, in turn, bore seed balls; and from this seed he obtained his Carman Nos. 1, 2 and 3. On its introduction. Carman No. 2 was given the name of Rural New Yorker No. 2. Sir Walter Raleigh was produced from seed of the Rural New Yorker No. 2. Carman's productions have added millions of dollars to the productive wealth of the States of New York, Michigan, Wisconsin, Iowa and Minne- sota, and as yet there seems to be no diminution in their vigor. Breeders From a Few States. — Thus far all of the potato breeders discussed have been residents of some half-dozen states, all of which, except Ohio and New York belong to the New England group. The chief centres were New York and Vermont. It would hardly be fair, however, to claim that nothing liad been attempted in the Middle West in tlie development of new varieties. Among those who have been most prominently identified with this work might be mentioned the names of Martin Bovee of Michigan, Thomas Craine of Wisconsin, and F. B. Van Ornam of Iowa. Bovee originated Bovee, Early Michigan and Pingree. Craine gave us June Eating, Keeper and Potentate. Van Ornam's con- tributions were Extra Early (Burpee's) and Great Divide. In concluding this enumeration of nineteenth century potato breeders, we do not claim to have mentioned all who are entitled to recognition, nor that the list of varieties given represents all that each of them originated. The object in mind has been rather to give a running history of potato breeding from the middle of the century to its close, in order to show what influence each of the men mentioned may have exerted on the potato industry of the country as a whole, and to bring together in a concrete way such data as would seem to be most important to those inter- ested in potato breeding. FENN'S PRODUCTIONS 391 Potato Breeding in Europe. — It is interesting to note that potato-breeding activities in Europe were coincident with those in America. That this should have been the case is not unnatural, because the same severe losses from late blight had been sustained by the European growers, and therefore the same necessitj' existed for the im])rovement of the potato through the development of more vigorous growing varieties. Work of Paterson. — In Great Britain the name of William Paterson of Dundee, Scotland, stands out prominently as a pioneer in potato breeding work. According to Wright and Castle,-'' he was probably the first person to cross-pollinate the potato. His first experiments were made in 1826, but it was not until 1856 that he produced anything of merit. Paterson's Victoria (1856) is regarded by many as the beginning of distinct progress in potato breeding in Great Britain. In addition to the Victoria, Paterson originated many others, but his fame as a breeder will always rest on that variety. Fenn's Productions. — In many respects the work of Eobert Fenn, in England, is very similar to that of Pringle, in America. They were both intensely interested in potato breeding and for a time kept up an active correspondence. Some reference has al- ready been made to this correspondence, and certain extracts given of one of Pringle's letters. Similar extracts are now presented from one of Fenn's letter to Pringle under date of January 27, 1876, the citation being taken from Fenn's article "Looking Back," previously given. In this letter he says: "I seein already to have entered into your ideas concerning the mingling of blood of English and American kinds. For three years consecutively, though as yet ineffectually, I have tried to cross my Rector of Woodstock seedling with your Rnowflake. as being the very best of the American varieties sent over to us. Snowflake refuses to produce me a globule of pollen or to become impregnated ... .This also has been the case with other American varieties, till this season a stool of that shy bloomer, Willard's Seedling, threw a stalk of flowers and. to my great satisfaction, gave me some pollen upon my thumb nail. I immediately applied the dust to the pistils of three prepared florets of my seedling Bountiful, and, in a few days. I had the inexpressible satisfaction to find impregnation complete, and the berries steadily growing. Again, some three years ago, after applying the pollen of Bountiful to some hundreds of pistils on the blossoms of the American Late Rose, I was in despair until two farewell bunches of flowers appeared in the row, when, as a last resort, I again applied the pollen of Bountiful and perseverance gave me five impregnated berries." 392 POTATO BREEDLNG AND SELECTION Fenn's first crosses were made in 1857 between Old Red Regent and American Black Kidney, also between American Black Kidney and English Red Regent. He used American varieties freely in his crosses. James Clark should also have a place among potato breeders of his time on account of his Magnum Bonum, which, according to Dean,^ was the result of a cross between Early Rose and Paterson's Victoria made in the early seventies. It was intro- duced by Sutton in 1876. For a number of years, the Magnum Bonum was very popular in Great Britain and elsewhere on account of the fact that it was a strong grower, comparatively free from disease, productive and of fairly good quality. The blood of the Magnum Bonum represented the best of American and Brit- ish varieties. Findlay's Up-to-Date, introduced toward the close of the nineteenth century, established such a reputation for this famous potato breeder as to make his subsequent productions very much sought after. These will be noted uiider twentieth century development. The Up-to-Date very largely supplanted Clark's Magnum Bonum. Other British Breeders. — The good work done by Carter, Chapman, Daniels, Fidler, Forbes, Harris, Kerr, Sharpe, Sutton and Webb attests to the deep interest taken in the improvement of the potato by the potato breeders of Great Britain. The Vilmorins in France have always been active in the conduct of plant breeding work. As a rule, however, there does not seem to have been as much interest taken in the potato by the French plant breeders as in Great Britain and Germany. The work of Wilhelm Richter, in Germany, affords a strik- ing example of what may be accomplished l)y concentration of effort upon a certain specific thing. In 1869 Richter became greatly interested in the improvement of the potato.^'"' At that time, the starch content of the potato in Saxony ran from 9 to 11.5 per cent. Potatoes of English origin dominated the German market. In 1875, at the exhibition of Allenburg, Richter was able to show a number of promising seedlings, such as Richter's Imperator, Precious Stone and others. His Imperator proved to be a particu- larly valuable variety, and Improved Imperator is still a leading German variety. Paulsen and Cimbal have also contributed much to the development and improvement of the potato in Germany. TWENTIETH CENTURY PROGRESS 393 Twentieth Century Progress in Potato Breeding. — In many respects, the actual progress made in potato breeding in this country since 1900 falls far short of that made from 1851 to 1890. Convincing evidence of the truth of this assertion may be obtained by a careful j^erusal of the seed catalogues from 1867 to 1890. No such activity can be sho"\\ai in any later period, nor can anything like as good descriptions of the newer introductions be found in our present day catalogues. This apparent decadence of interest in potato breeding may be partially explained by the fact that, during the nineties, the extremely low prices of farm products had a depressing effect on the potato industry. Another factor which may have served to lessen interest in potato breeding was that, with the introduction of the Green Mountain and Eural types of potatoes, so admirably adapted as a late crop in the northeastern United States, there was little incentive to indulge in this line of effort. In Europe, on the other hand, during the first few years of the century, the world never witnessed, and probably "\vill never again witness, such wild excitement as prevailed during the intro- duction of Sutton's Discovery, and Findlay's Northern Star and Eldorado. The high prices paid for these varieties were largely due to the fact that they were heralded far and wide as being almost immune to late blight. A similar mania j^revailed in America during the years 18G7 to 1869. A sale is recorded^^ in the Spring of 1868 of 150 bushels of the Early Eose for $1,000 or an average price of $66.66 per bushel. The May issue of the American Agriculturist 1868, p. 153, contains the announcement that a portion of the 150 bushels had been re-sold at $80 per bushel. Beecher,^ in his essay on "The Potato Mania," states that as high as $50 per tuber was paid for Bresee's King-of-the-Earlies. Although a number of new varieties have been introduced by American seedsmen since 1900, it can hardly be claimed that much progress has been made along this line. The two acquisitions that offer much promise are the russet type of the Burbank and Rural group. Nothing definite is known about the origin of the Eusset Burbank. So far as it is possible to determine, the Eusset Eural appears to have originated in Michigan. This iy^e of Eural has recently been accepted by growers in some sections of Michigan as their standard commercial variety. 394 POTATO BREEDING AND SELECTION Lack of familiarity with the newer introductions abroad, other than those mentioned, does not permit of making comparisons be- tween them and those which were being grown commercially prior to 1900. There can hardly be said to be any lack of interest among potato breeders, as will be indicated by some of the names here presented, all of whom have been more or less actively engaged in an attempt to improve the potato. This list is as follows : Berthault, Dean, Findlay, Freckmann, Seelliorst, Heckel, Paton, Salaman, Sutton, Taylor and Wilson. It is needless to say that this list by no means represents those who are actively engaged in potato-breeding work. Difficulties Involved in Potato Breeding. — One of the chief difficulties confronting the potato breeder is due to the fact that so many of our most desirable commercial varieties bloom very sparingly, if at all, in some localities, and that, as a rule, the most of them do not produce viable pollen in sufficient amount to impregnate the ovaries of the flowers to which it is applied. This statement applies almost equally well to the free blooming as to the shy blooming varieties. Another difficulty encountered ])y the breeder is that untoward seasonal conditions at the time the blossom buds are forming may wholly prevent the full development of the flower, and, conse- quently, the opportunity to make crosses is lost. A further drawback to progressive work in potato breeding is due to what might be termed the irony of fate, in that the few varieties which do produce ample viable pollen are more or less unsatisfactory from a commercial standpoint, with the result that the seedlings derived from the use of such ])ollen inherit many of the undesirable characteristics of their male parent. Flowering Habits. — In discussing the llowering habits of our commercial varieties East^ makes the following statement : "If we regard blossoming as invariable at some period of tbeir life under the proper conditions, we can then divide potato varieties into several classes. 1. Varieties whose buds drop off without opening. 2. Varieties in which a few flowers open, but fall immediately. 3. Varieties whose flowers persist several days, but rarely produce viable pollen." He estimates that about GO per cent of our named varieties belong to the first class, and, of the varieties that do bloom, only 60 per cent have their blossoms persistent for more than one day. ABUNDANCE AND VIABILITY OF THE POLLEN 395 East further found that unseleeted two-year-old seedlings gave nearly the same percentage of plants that dropped their huds before opening, the figures being 56 and 4-i, respectively. From these data he made the following deductions : " This approximately equal percentage of the different classes, both in seedlings and in named varieties, indicates that their sexual differences are inherited as distinct characters, and are not due to increased tuber formation." Observations of the writer do not substantiate those of East relative to the percentage of non-flowering varieties, nor do they necessarily refute them, if we regard his data as merely applying to the particular locality in which his studies were made. The percentage of varieties belonging to any given class varies with the region, and is very largely dependent upon the climatic conditions under which the plants are grown. In a previous publication^^ the writer made the following statement : "Most varieties will produce some blossoms when grown under optimum conditions for the normal development of the plant, particularly if these conditions prevail during the stage at which flower buds are formed. In any considerable varietal collection it is inevitable that many varieties should find the conditions unsuitable for their maximum development." As a result of over a quarter of a century's intimacy with a large varietal collection, the writer has come to recognize the fact that varieties belonging to certain groups or classes of potatoes bloom freely or sparsely according to the particular group to which they belong. For example, the members of the Irish Cobbler, Early Michigan, Early Eose, Beauty of Hebron, Green Mountain, Rural, Peachblow and Up-to-Date groups bloom profusely to very pro- fusely in northern Maine; those of the Early Ohio and Burbank groups are only moderate bloomers, while those of the Triumph and Pearl grouj)s are very sparse liloomers. Abundance and Viability of the Pollen. — Great variations are found in varieties with respect to the quantity and viability of the pollen produced by them. During the years 1903 to 1907 the writer had an opportunity to observe the behavior of a Avild Mexican species. Solarium polyadenium, with respect to the formation of seed balls. It was noted that while it bloomed rather freely throughout the growing season it seldom developed seed balls until the latter part of the summer. Examination of the stamens showed that it was not due to lack of pollen, and that its failure to develop seed 396 POTATO BREEDING AND SELECTION balls was apparently due to a lack of viable pollen. In plant breed- ing studies extending over a })eriod of sixteen years it has been the writer's privilege to examine the stamens of a great many varieties, and in but few instances has an abundance of viable polle]i been found. The data show a very much larger proportion of foreign varieties producing viable pollen than of x\nierican varieties. Of the many varieties studied in the twelve groups mentioned, only four were noted which could lie regarded as dependable sources from which to obtain viable pollen. These four American varie- ties were Early Silver Skin, Keeper, McCormick and Bound Pinkeye, all of them undesirable from the standpoint of their table quality, smoothness of surface, color of skin or productiveness. There are times, however, when it is possible to secure sufficient viable pollen to make artificial crosses from varieties belonging to the Burbank, Green Mountain and Eural groups; and less infrequently from the Irish Cobbler, Triumph, Early Michigan, Early Eose, Early Ohio, Beauty of Hebron and Pearl groups. The Peachblow group is omitted because the McCormick and Round Pinkeye are members of that group. The varieties, Early Silver Skin and Keeper, do not fit into any of the groups mentioned. More recently certain varieties of foreign origin, such as Busola and Petronius, have been- found to produce an abundance of viable pollen and they seem to transmit desirable qualities to their offspring. In a rather recent publication Salaman''' announces that male sterility is a dominant Mendelian character. THE TECHXIC OF rOTATO BREEDING The first consideration in the technic of plant breeding is that of the character of the flowers borne by the plant which one desires to cross. The flowers of a plant are either perfect or im- perfect. Perfect floAvers are those which possess both stamens and pistils; imperfect ones those which are devoid of one or the other reproductive organ or organs. The potato plant bears perfect flowers, and is of such simple structure as to render the task of crossing it comparatively easy (Fig. 205). Structure of the Pistil. — The pistil of each flower is morpho- logically divided into two parts, viz., the st3'le and the stigma. Each potato flower bears but one pistil (Fig. 206), the style of which varies from six to nine lines in length, and from one-third to STRUCTURE OF THE STAMENS 397 two-thirds of a line in diameter. Usually, the shorter the style, the fleshier it is. Some styles are greatly curved, and in some varieties there is a distinct spiral twist as in Up-to-Date and Factor. Others are perfectly straight. The two-lobed stigma also varies considerably in size, some being only slightly enlarged and somewhat cup-shaped, while others are considerably enlarged, having well-rounded lobes covered with short papilla. Structure of the Stamens. — The potato flower normally pos- sesses five stamens, but occasionally four or six are noted. In some varieties six stamens are of quite frequent occurrence. The stamens have short, thick iilanicnts with laro-e, tleshv, erect anthers, which Fig. 205.— Potato flower natural size show- Fig. 206.— Potato flower with sta- ing stamens and pistil. mens removed showing naked pistil. usually stand close together around the style, like a cone in the centre of the flower (Fig. 205). The anthers may vary from three to five lines in length and one to one and one-half lines in breadth, and about one line in thickness. The placenta, which divides the anther longitudinally into two equal cell-like compartments, is rather thick and fleshy. The halves or lobes of the anthers have small terminal pore openings for the discharge of the ripe pollen, which are produced on the inner surfaces of the cell. In many varieties, the anthers are so poorly developed that the terminal pores do not open, though they are not so undeveloped as to be devoid of pollen. In such cases, the membranous outer covering of each anther lobe or cell may be slit open, and the pollen grains scraped off into a receptacle by means of a scalpel, forceps or needle. Usually, however, such pollen is not viable, and one should, therefore, reject such varieties for pollen purposes. The color 398 POTATO BREEDING AND SELECTION of the stamens varies greatly with different varieties. Some are a pale lemon-yellow, while others are a bright orange-yellow, with all the intergradations of color between these two. Only one A B Fig. 207. — -Potato flower cymes. A shows three floweri which micht bo used for arti- ficial pollination, though only the upper right hand bud is at the right stage. Cyme B has two buds at right stage. Fig. 208. — Cymes A and B after emasculation. Note protruding pistils in lower flow- ers of cyme A. instance has come under our observation in which the color of the stamens did not answer to the above description, and that was in the case of a wild Mexican species, Solarium cardiophyllum lanceolatum, (Berth.) Bitter, where the anthers were chocolate- brown with a slight tinge of purple. Usually varieties with pale, ARTIFICIAL CROSS-POLLINATION 399 lemon anthers do not produce pollen freely and, as a rule, it is not viable. A considerable variation has also been noted in the turgidity of the anthers, usually those of a pale lemon-yellow color are less turgid, and are more loosely arranged around the pistil. Often this looseness is in the nature of a distinct curving outward of the central portion of the anther, the tips of the anther clasping the pistil. Generally this type of flower has one or more defective stamens. On the other hand, it has been observed that some of those having a deep orange-yellow color, like those of Solanum Fig. 209. — Emasculating the flowers. Maglia, are so firm as to be almost coriaceous. Flowers of this class seldom, if ever, produce an appreciable quantity of pollen and, as a rule, it is not vial}le. Artificial Cross-pollination. — The actual process of cross- pollinating potato flowers is comparatively simple; but since relatively few of our commercial varieties develop viable pollen, the percentage of success is usually small, unless the operator employs pollen from varieties that produce it freely and that is known to be highly viable. The first step in the cross-pollination of the potato is obviously that of the selection of the parent plants. Strong, healthy plants should be chosen, of a variety possessing certain definite characters which it is desired to combine with certain other desirable characters of another plant. The next step is the selection and emasculation 400 POTATO BREEDING AND SELECTION of the llowers to which pollen is to be applied, and the bagging of the same (Figs. 207 to 213). The proper stage at which to emasculate the flowers is usually about 24 hours before the buds normally open. This stage is shown in figure 207-B. The only instrument necessary for the removal of the stamens is a sharp, pointed forceps (Figs. 209 and 212). To perform the operation, clasp the lower portion of the bud between the forefinger and thumb of the left hand and, with the forceps held in the right hand, slit open and push back the Fig. 210. — A simple anil handy pollinating kit. corolla, after which the fleshy anthers can be easily and quickly removed by pressing each of them backward from the pistil until it snaps from its filament. Figure 206 shows a blossom from which the stamens have been removed in the manner described. It is usually desirable to emasculate as many flowers in each cyme as are at the right stage of maturity. All those that are too imma- ture or mature should be removed before inclosing those that have been emasculated in a paper bag (Figs. 209 and 213). A one- pound bag, that is, a paper sack having a capacity mark of one pound is large enough for this purpose (Fig. 211). The work of putting on the sacks can be greatly facilitated by perforating the tops of the sacks and running strings through them, prior to their use in the field, as shown in figure 211. An- other feature that has proved satisfactory is that of inclosing with ARTIFICIAL CROSS-POLLINATION 401 the flowers the young shoot ou which the flower cyme is borne, or where this is not feasible, as much foliage as possible. The iuclosure of the foliage serves a two-fold purpose, that of protecting the flowers by keeping the bag distended, and, in sup- plying moisture through leaf transpiration. The flowers are usually ready for pollinating one or two days after emascu- lation, depending upon the stage of maturity when emasculated and the char- acter of the weather subse- quent to it. Salaman^"' and East" regard the covering of the flowers with bags as an unnecessary procedure and likely to cause injury to the pistil. On this subject Salaman says : "All my work has been carried on without placing the flowers in bags. The reasons for not adopting special pre- cautions were that, when bagged, the flower invariably drops; that bees and the like never approach a potato flower, though a srnall fly often lives in the bottom of the corolla; that the flower is con- structed for self-fertilization; and that the quantity of pollen is so scanty as to render fertilization by the wind in the highest degree improbable." East says : " We may conclude that if we cut off' all the uppermost cymes from the plant stems, and use for pollination only emasculated flowers of those borne next in order, the relative probability of our crosses being interfered with is negligible for all practical purposes. This removes the neces- sity of shutting out the light and air circulation by means of bags. It is also worthy of note that the chances of success are much greater if the calyx and corolla are not removed during emasculation, as the style is very slender and is likely to be injured." 26 Fig. 211. — One pound paper bag ready for use. 402 POTATO BREEDING AND SELECTION While it is true that the pistil of the flower is easily broken off, and that few insects visit the flowers, it is not necessai-ily true that the inclosure of the emasculated flowers in paper bags causes aiiy more of them to drop off than if left uncovered, provided the oper- ator follows the suggestions given relative to including as much foliage with the flowers as is possible. The beneficial efi^ect of the foliage has already been mentioned. Method of Collecting and Applying Pollen. — Many methods have been pursued by the writer in collecting pollen, but none have proved as satisfactory as the one which is now followed. This Fig. 212. — Jarring the Fig. 213. — Enclosing the impregnated flowers in ija- pollen from the anthers on per bag and recording the cross, thumbnail. method consists in gathering the flowers, as needed, from the plants which have been selected as pollen parents. When a large number of emasculated flowers are to be crossed and different pollen parents are to be used, it has been found expedient, as well as satisfactory, to collect a number of flowers of the varieties desired, which are at the right stage of development, that is, when the terminal pores of the anthers have just opened. Each lot collected is placed in a separate bag, the bags being similar to those used for inclosing the emasculated flowers. Each bag is properly labelled with the name of the variety or of its field number. In this way the operator may carry a considerable quantity of available material with him, which can be readily drawn upon as desired. When the pollen of any particular variety in the pollinating kit is desired, a flower is selected from the proper bag, the corolla is pushed back between COLLECTING AND APPLYING POLLEN 403 the forefinger and thumb of the left hand and held in such a position tliat the anthers extend upward on the thumb nail (Fig. 212). After removing the pistil, the anthers are tapped sharply with the forceps, thus jarring the pollen out of the terminal pores, upon the thumb nail on which it is readily conveyed to the stigmas of the previously uncovered flowers. The cross is then recorded in a field note book, and its number placed on a string tag, wdiich is attached to the pedicel of the flower cyme, after which the pollin "Fig. 214. — Seed balls eight days after application of pollen. ated flowers are again inclosed in the paper bag, care being taken to include as much foliage as possible, and to avoid injury to the pistils. Generally the success or failure of a cross can be deter- mined in a week from the date of applying pollen. Frequently the seed balls at this date will be two-thirds grown (Fig. 214). The rate of development is largely dependent upon two factors, viz., the natural affinity of the plants crossed, and the amount of viable pollen applied to the stigma. As a rule, the paper bag should be removed in seven days. At this time the seed balls of all successful crosses should be inclosed in a loose cheesecloth sack, 404 POTATO BRKKDING AND SELECmON securely tied to the stem of the plaut in order to keep it off the ground, or from breaking the flower stalk, when the plants begin to mature. Percentage of Successes. — In some studies made by East (I.e. p. 36) to determine whether the uppermost, intermediate or lower flower cymes produced the largest quantity and the most viable pollen, he found that crosses, resulting from the application of pollen from such sources gave the following percentages of suc- cesses. Upper C3'mes ^8 per cent; intermediate 52, and the lowest cymes 18 per cent. He states that these experiments were made on plants of a variety that naturally produced an abundance of pollen. In our own Avork there have been numerous failures as well as many successes. In the earlier years or between 1903 and 1908 very few successful crosses were made, certainly less than one per cent; but in 1909 the percentage of successful crosses Avas quite large. This was especially true in those cases in which pollen had been used from a variety known to produce a high ])ercentage of viable pollen. In some instances, every flower pollinated bore a seed ball. The data contained in the following table embody the results secured by the writer in 1909, while in the employ of the Vermont Agricultural Experiment Station and which were prepared and published in U. S. Department of Agriculture Bui. 195. A study of these data shows that 458 seed balls were produced from a total of 1,599 crosses. This represents an average of 28.6 per cent for the Avhole number crossed. When one takes into consideration the fact that a large percentage of these crosses were entire failures, indicating the use of worthless pollen, they can appreciate the fact that when the proper pollen is ajiplied to a receptive stigma the percentage of successes will be high. If we analyse these data carefully, we find ample corroboration of the above statements. The following analysis is taken verbatim from the publica- tion mentioned. "A study of the table discloses some rather iiiterestiiii,' data, particu- larly with respect to the behavior of seed-bearing plants when pol- linated with dillerent varieties. In the first cross recorded, Oeheinirat Theil X Keeper, six flowers were pollinated and five seed balls were developed from which r)02 tuber-bearing plants Avere produced. The same variety when mated with XX ICarly developed only one seed ball from 11 pollinated flowers, and this did not produce a single tuber-bearing plant. When crossed with Holanum Maglia, a wild South American species, it failed to set fruit; and the same negative results were obtained when RECORD OF POTATO CROSSES 405 :? :? ^^ w g^ g^ g^ g^ 2^ O o o m ri 1 xxxxxxxxxx p o- y CO s ■ "^ s ?i i X X >1l CO Oi 1x3 00 *>. O CO 1— o lO Ci 'XI O 0^ O O O CJ o O O O 4^ O O tv N3 CO CO _ -^ >^ O ^^opciooopoo o k)oo' go' ■ CO' ■ 'tj^ o m y a. 3 a" (t. lis- E o ro 406 POTATO BREEDING AND SELECTION pollen of the unnamed IMexican species of Solanum was used. We know that 8. Maglia produces pollen very sparingly and that frequent attempts to germinate the pollen in the laboratory have been unsuccessful. The Mexican species is known to produce viable pollen in abundance, how- ever, so that in this case the failure to set fruit was probably a clear example of non-uflinity. The next female parent, Sophie, crossed with Keeper, gave excellent results. Sophie is a German variety possessing qualities of vine and tuber strongly resistant to late blight. From 20 Fia. 215. — A South American variety with clusters of naturally fertilized seed balls. pollinated flowers 16 seed balls were developed. The seed from the 16 seed balls produced 2,244 tuber bearing plants, or an average of 140.3 plants per berry. The 4 pollinated flowers of Sophie X Fuerst Bismarck failed to develop a single berry. A similar result was obtained from 8 flowers pollinated with Empire State and from 4 pollinated with Garnet Chili. Sophie X Irish Seedling produced 4 seed balls from the 4 flowers pollinated. The seeds from these berries gave 707 tulier bearing plants, or an average of 176.8 plants per berry. Three flowers pollinated with Venezuela failed to set fruit. It is clearly evident that the varieties Fuerst Bismarck, Empire PERCENTAGE OF SUCCESSES 407 State, Garnet Chili and Venezuela either did not develop viable pollen or the pollen tubes were unal)le to reach the ovules of the flower. It is known that all of these varieties produce pollen sparingly, and it is probable that an insufficient quantity of viable pollen was present to efl'ect the cross. " In the first cross of the third seed parent, Professor Maerker X Apollo, both the seed and pollen parents are of German origin, the latter being one of the most disease-resistant varieties in the collection. Nine seed balls are recorded from 12 flowers pollinated and 275 tuber-bearing plants Fig. 216. — ^An Irish Cobbler plant bearing several clusters of seed balls the result of artificial application of pollen. One cheesecloth sack removed to show the berries. were obtained from this lot, or an average of 30.6 plants per berry. Fifteen flowers pollinated with pollen from Early Silverskin produced 15 seed balls, from which 555 plants were obtained," an average of 37 plants per berry. When crossed with Keeper, 12 seed balls were developed from 13 flowers and these, gave 320 plants, or an average of 27.2 plants per berry. Pollen from Rand's Peachblow proved ineffective. " It is interesting to compare the results from the two crosses, Sophie X Keeper and Professor Maerker X Keeper. In the first instance the percentage of success is 80 and in the latter 92.3. Carrying the compari- 408 POTATO BREEDING AND SELECTION \ Fig. 217. — Several seed balls showing different views of the fruit or berry, also the position and relative size of the seeds. Half size. REMOVING THE SEEDS 409 son farther, however, we find that the first cross averaged over 140 plants per berry, while the latter averaged only 27.2. These data make it at once apparent that some varieties develop fewer ovules than others." Gathering the Seed Balls. — The seed balls should be allowed to remain on the plant until they are mature (Figs. 215 and 216), or until danger from frost makes it desirable to gather them. When gathered they should be placed in a moderately warm room to insure thorough ripening. Unless the cluster of seed balls is large, they are allowed to remain in the sack until they are thor- oughly ripe. Most seed balls, when ripe, are usually of a pale lemon-yellow color; but some of the foreign varieties, or those Fig. 218. — Seedling potatoes ready to be potted off or pricked out into flats. having foreign blood in their parentage, are of a purplish- black color. Removing the Seeds. — The usual practice is to remove the seeds as soon as the seed balls are ripe (Fig. 217). This is most easily accomplished by crushing the seed balls into a pulp, and dropping them into a vessel of water in a warm room. They should be allowed to remain in the water for a few days, or until sufficient fermentation takes place to cause the pulp to rise to the top. Frequent stirring of the contents of the vessel during this time will hasten the separation of the seeds from the pulp. When the seeds are largely separated from the pulp, the latter may be floated ofE the top of the vessel by running water into it; after this the water can be poured off through a strainer or a cheesecloth to collect the seeds, which should then be dried in a moderately warm room. When dry, they should be placed in a packet and properly labelled. 410 POTATO BREEDING AND SELECTION In this condition, they may, if so desired, he held several years, without material lessening of their viability. Method of Growing Seedlings. — Various methods may be employed in the growing of potato seedlings. The one practised by the writer is that of sowing the seed in flats or earthen seedpans in the greenhouse about the last of March, the soil used being a light, sandy loam of moderate fertility. The seeds are sown in Pig. 21 'A than the average. iiotato seedlings. Th about the same nuinner as pepper or tomato seeds, and covered to a depth of about one-eighth of an inch. Under favorable con- ditions, well-matured seed will begin to germinate in from 4 to 6 days, and in 10 days to two weeks most of the seeds will have started to grow. In from four to five weeks they will be ready to trans- plant (Fig. 218) to other flats or to be potted off into two and one- half-inch paraffin paper pots. With careful attention to watering and room temperature, these plants should be ready to transplant into the open about the last of May or first of June (Fig. 219). At this time, if well grown, they should be stocky and thrifty plants of from 4 to 5 inches in height. A night temperature of HARVESTING THE SEEDLINGS 411 from 55 to 60 degrees ¥., with a rise of 20 degrees during sunshiny days and 10 degrees in cloudy ones, will insure a moderate and healthy development of the plants in the greenhouse. The foregoing outline of procedure is not intended to convey to the reader the impression that a greenhouse is necessary to start seedling potatoes. They can be grown in a hotbed, or they may be started in the living room of the house or anywhere else in which there is sufficient heat and light, after they germinate. The same methods can be followed as for tomatoes or peppers. It is desirable to start the potato seedlings early in order to give them a long growing season, so as to insure good tuber develop- ment the first season, thereby making it possible to discard the undesirable ones and thus reduce the number to Ite tested the ensuing year. Field Culture of the Seedlings. — Do not make the mistake of planting the seedlings too close. Long experience has demon- strated that a spacing of 30 by 36 inches is none too much. The rows are spaced three feet apart and the plants 30 inches in the rows. Even at this distance, it will often be found that many of the plants will more than cover the space allotted to them ; their long, tuber-l)earing stolons will intermingle, making it difficult to distinguish whether the tubers belong to the one or the other of the two adjacent plants in the row. The culture accorded the seedling plants, after transferring them to the field, is not essen- tially different to that which should be given to commercial varie- ties. Every effort should ])e made to provide them with as good growing conditions as possible. Thorough spraying is essential to protect the foliage against insect and fungous pests, in order that an intelligent reading may be obtained on their behavior the first season. Seedlings from different crosses frequently show great variation in habit of growth and vigor of vine, making it possible to obtain a fairly accurate reading from the F^ generation (first year seedlings) of the value of different varieties as parent plants. Harvesting the Seedlings. — In many respects the harvesting of the seedlings is the most interesting feature of this work. The striking differences that are met with in seedlings of different parentage, or even of the same parentage, are sometimes rather puzzling. One seedling may produce rough, uneven tubers, while the adjoining one may have smooth ones (Figs. 220 and 221). In like manner, the shape of the tuber may vary in every conceivable 412 POTATO BREEDING AND SELECTION iiuuiiier; sonic hoing so knobby as to be absolutely wortliless, or so deep-eyed as to give the surface of the tuber an irregular appear- ance. Similarly, all gradations in color may be noted. With the harvesting of the seedlings comes the first, real, selective process connected with the raising of seedling potatoes. All plants having irregular tuber progeny, deep-eyed, undesirable in color, or that are too. numerous, should be immediately discarded. Only those that are of good shape should be retained (Fig. 221). Our present practice is to take notes on the number, size and shape of tubers, frequency and depth of eyes, color of skin, and general desirability Fig. 220. — A decidedly unpromising first year seedl of the tubers as a whole. This information, while in nowise exhaustive, affords a basis for the study of inheritance of certain tuber characters, and may furnish important data on the trans- mission of parental characters. Such data, if properly interpreted, enables the breeder to carry on his work witli a greater degree of intelligence; and may even permit him to predict, with more or less accuracy, what may be expected from the progeny of certain parents. As each selection is made in the field, a number is assigned to it in the notebook. This number is also written on a string tag, A^th a perforated, detacliable stub, whicli is inserted in the selected hill and serves to indicate those which are to be saved. Each selec- tion is picked up separately in small cotton or gunny sacks or in HARVESTING THE SEEDLINGS 413 stout maiiila paper bags, the stub, with number affixed, is torn oft' and placed in the bag, while the string tag proper serves to tie the bag, and indicates by the number on the bag which seedling selection it is. The stub inside is a safeguard against the loss of the outer tag or the number affixed thereto. Usually no weights are taken of first year seedlings, except in the case of extremely high-yielding hills. The highest-yielding seedling thus far pro- duced by the writer weighed over nine and one-half pounds. The following year it has been our practice to grow five plants each of Fig. 221.— a . iiig first year seedling. the seedlings; occasionally, however, when the seedling seems unusually promising, ten plants are grown. Generally, whole tubers are planted in order to insure a perfect stand, besides effecting a considerable saving in time which would necessarily be involved in the cutting of a large number of small lots of seed. The five plants are sufficient to study the habit of growth of the seedling, its resistance to disease and its tuber development. As they are harvested, the same rigorous selection is practised as in the first season. From this period on, larger plantings are made of the more promising ones (Figs. 222 and 223). U^]ually it is not safe to introduce a seedling until it is five or six years old ; . although 414 POTATO BREEDING AND SELECTION there are exceptions to this statement, as in the case of the Burbank and Early Ohio, Avhich were three and four years old, respectively, when first introduced. The growing of seedling potatoes on a large, or even on a moderate scale, is an expensive proposition, and offers little com- pensation to those engaged in the development of new varieties. POTATO IMPKOVEMENT BY SELECTIOX The improvement of the potato by selection is a field of endeavor in which every grower interested in the problem of increasefl production per acre can engage. While, as has been previously 1 IK 11-, notts „ii Mt llui^ ijotatoi.-,, Pie.-,(iUL: Lsle, Me., 191S. Note two Uiscastd occtlhiD^s 111 llic foie^round noted, the limitations in selection are much more restricted than in the case of breeding, in which sexual reproduction plays an important role, it is, nevertheless, by no means as limited as might be supposed, as more or less variation already exists within most of our cultivated varieties. These variations express themselves in a multiplicity of ways, such as uniformity in size and shape of tuber and the number produced per plant. Some plants may produce 2 or 3 large tubers, others the same number of large tubers but with a half- dozen or more small ones, while still others may be found producing from 6 to 10 or more medium-sized merchantable tubers with prac- EARLY ATTENTION TO SELECTION 415 tically no small ones. It is plainly evident that the progeny of such plants as those last described are more desirable than those of the other two. In like manner it is conceivable that certain variations may occur in the plant itself. Such variations may be expressed in any of the following attributes of the plant proper: 1. Disease resist- FiG. 223. — Taking notes on potato seedlings at Presque Isle, Me., 1918. Note flo- riferous habit of plants in central portion of picture. ance. 2. Drought resistance. 3. Heat resistance. 4. Greater vigor. 5. Greater adaptability to peculiar environmental conditions of soil and climate. It is quite possible to conceive of other variations which might be well worth considering. It is the business of the selectionist to detect and isolate these variations and, through careful testing, determine whether they are heritable variations transmissible from one generation to another, or whether they are merely accidental variations due to a larger supply of moisture, plant food or some other external factor. Early Attention to Selection. — That the subject of selection is not a new one, and that its possibilities were recognized by earlier investigators, is amply substantiated by the following examples. In 1795, Anderson,^ in a communication to the potato Com- mittee of the Board of Agriculture of Great Britain, suggests the possibility of greatly increasing the yield of potato varieties 416 POTATO BREEDING AND SELECTION by selecting seed from productive })lant.s, and growing the progeny of each selection separately, in order to ascertain which was best. That he tlioroughly understood the i)rinciples of selection, as they are known today, is clearly evident, because he was careful to sug- gest that some productive plants will not transmit this character to their progeny. While Anderson does not actually present experi- mental data to substantiate his views, he makes the assertion that he can "speak from experience with great certainty; and can affirm that, by a careful attention to these circumstances, a farmer in a very few years will, in many cases, more than double the amount of his average crop of potatoes, soil and culture being the same." One of the earliest experiments that has come to notice is one which was carried on by Hallet'^ l)etween 1868 and 1882. His account is as follows : " In the case of the potato, I have also applied my system, startiiifr every year with a single t\iber, the best of the year (proved to have been so by its having been found to produce the best plant) for fourteen years. My main object here has been absolute freedom from disease, and these potatoes are now descended from a line of single tubers, each the best plant of the year, and absolutely healthy, and concurrently with the endeavor to wipe out all tendency to disease, I have always kept in full view the point of increasing productiveness. The result may be thus shortly stated: Dividing the first twelve years into three ■periods, the average numlier of tubers upon the annual best plant selected was, for the first period of four years 16; for the second period of four years 19; for the last period of four years 27 ; or nearly double the number produced during the first series of four years. And if, as I might very fairly have done, I had confined the first period to the first three years (instead of four), the last period would have shown an average of 27 tubers against 13 in the first period, or more than double." The evident care with which this experiment was conducted, and the continued selection of the best plant based on freedom from disease and productiveness, would seem to indicate that Hallet had definite clear-cut ideas concerning the advantages of selection in building up vigorous and productive strains. Observations of Carriere. — Carriere'* in discussing variations in the potato says: " The potato furnished us with examples of modifications just as remarkable as those which we have reported for beans and for corn Every year, in reality, when we harvest the tubers and wish to conserve the purity of the variety, we are obliged to purify, that is, to make a choice and reject those which, as we say, have degenerated .... The modifications in the potato may occur equally well in the underground parts; that is what has liappened in the variety called Pousse-debout. FISCHER'S WORK 417 The name Pousse-debout has boon j^ivon to this variety because the tubers which it produces, instead of bein^ placed flat or nearly so in the soil, are arranged one aj^ainst (upon) the other, much like pieces of wood are disposed for transformation into charcoal." It is further stated by Carriere that the Marjolin potato is a variety possessing the peculiar quality of never flowering, and of being very early; but, notwithstanding this fact, it is continually producing plants which flower and produce seed, and which, owing to this fact, are not as early as the parent plant. Carriere also observed transformations or variations in color of flowers, shape of tubers, and season of ripening in the variety Chardon. He remarks that these variations in the Chardon are rather odd, because it had long been under his observation without having previously shown an}^ variation ■\\^hatsoever. Transmission of Productivity. — In all the selection work, carried on by Goft'^^ in 1884 and 1885, he demonstrated that tubers from productive plants gave larger yields than tubers from unpro- ductive plants, the total gain being a little more than 24 per cent, Fischer's Work. — In 1897 Fischer^" began some selection work with the potato in which variations in productiveness, shape and starch content of tuber, as well as habit of growth of the plant were studied. Fischer's work was very largely carried on in pots, under as nearly uniform conditions as possible, and yet the variations in the tuber yield were in some instances in the ratio of 100 to 233. The individual deviation within the variety itself was found, in the case of the Saxon onion potato, to be associated with certain definite characters; for example, flat-round tubers, rich in starch, were found to be correlated with a more or less restricted vegeta- tive growth and tuber yield. Long tubers, poor in starch, were, on the other hand, found to be correlated with strong vegetative growth and a high tuber yield, as compared with that of the fla^- round ones. This is strikingly illustrated in the following data, which give the relative proportion of dry stalks and tubers from the two types of mother tubers : Strain I. Flat-round mother tubers, rich in starch ( 18.68 per cent. ) ; dry stalks 100 per cent., tuber yields 100 per cent. Strain VII. Long mother tubers, poor in starch (11.83 per cent.); dry stalks 14.5, tuber yields 204 per cent. Fischer also noted the deviations within these types, and pre- sents data showing that, while a considerable deviation occurred, the 27 418 POTATO BREEDING AND SELECTION maximum yield from the flat-round type did not approach very closely to the minimum yield of the long type. These data show the following deviations : Strain II. Flat-round tubers, rich in starch; dry stalks 100 per cent; tuber yield 100 per cent. Strain III. Flat-round tubers, rich in starch; dry stalks 114.5 per cent; tuber yield 167 per cent. Strain V. Long tubers, poor in starch; dry stalks 142 per cent; tuber yield 216.7 per cent. Strain VI. Long tubers, poor in starch; dry stalks 175.5 per cent; tuber yield 233.3 per cent. It is observed that the plants from the fiat-round tubers were shorter jointed and matured earlier than those from the long tubers. This would indicate that the latter represented a later maturing strain. Productive vs. Unproductive Hills. — In December, 1904, Eustace* reported a rather interesting study on the behavior of '•j)roductive vs. unproductive hills." When harvesting the 1903 crop, Eustace selected the progeny of 125 productive plants and an equal number of unproductive plants. Weights were taken of the tubers from each of tlie 250 plants selected, a record being made of each; but after the weights were taken, no effort was made to keep the progeny of the productive hills separate; in other words, the experiment resolved itself into a mass selection. The unpro- ductive hills w^ere handled in a similar manner. In the following Spring, 10 rows of 232 plants each w^ere planted from the productive lot, and 5 rows from unproductive. The resultant production was at the rate of 362.25 bushels from tbe productive hills and 339.16 bushels per acre from the unproductive. The significant feature of Eustace's data is to be found in the deviation w^hich occurred ))etween the individual plants in the 1904 crop. The data shows the deviations were almost as great as in that of the original stock of the previous year. The 1904 deviations Avere 11.9 ounces or 39.18 per cent as against 9.37 ounces or 39.44 per cent in the 1903 crop. In this connection Eustace says : "That the variation was not materially reduced by the uniform con- ditions under which the experiment was made was a surprise. The conclusion is that factors, which are apparently unimportant, produce wide differences in yield.'" From our present knowledge of the behavior of individual hills even though PRODUCTIVE VS. UNPRODUCTIVE HILLS 419 Eustace's studies had been made with the progeny of the individual hills instead of in mass selection, it is questionable whether the deviations would not have been just as great as those noted. At the annual meeting of the American Breeder's Association, in 1907, Waid^* reported the results of similar studies to those of Eustace. This work was conducted at the Ohio Experiment Station during the seasons of 1904 to 190G inclusive. Seed was selected from j)roductive and unproductive plants in the fall of 1903. The three-year average from high- and low-yielding plants was found to be 1.38 pounds for the former, and 0.73 pounds for the latter, or a difference, in favor of the high-yielding plants, of over 89 per cent. A comparison between the j)roductive plants and those grown from the common or unselected bin-run stock, showed a gain of over 25 per cent in favor of the productive stock. The most interesting feature of Waid's data is brought out by a comparison of the average weight of the tubers from the ten high-yielding hills selected in 1903, and the three-year average from these original hills. The average of the ten original hills was 2.38 pounds per plant, whereas the three-year average is only 1.38 pounds or a decrease of almost 42 per cent. The inference suggested by the data is that, in the selection of high-yielding hills, one is not at all certain what proportion of the hills are likely to maintain their seemingly productive character. Eecent observations regarding the behavior of high-yielding hills lead to the belief that less real progress will, as a general thing, be made by selecting the very high-yielding hills. In fact, there is con- siderable evidence accumulating which would indicate that the practice is not to be recommended. In this connection. East's'* statement with reference to his experience with high- and normal- yielding hills from a select strain of Eural New Yorker No. 2 would seem to offer supporting evidence. He reports his obser- vations as follows : " In 1906 we had in stock a supply of the well-known variety Rural New Yorker No. 2, which had heen grown from a single hill in 1904. A selection of tubers from the five best-yielding hills was planted in 1907, and compared with five normal hills producing only one-half as much. The five best-yielding hills averaged 1.200 grams (2 pounds 10 ounces) of tubers per hill, with an average set of eight tubers. The check hills averaged 600 grams, with a set of four tubers each. Ten hills were planted in each case, two tul)ers being planted from each hill. In every case, pieces of about the same weight were planted. The yield from the high- yielding selections was at the rate of 101 bushels per acre, while the yield from the check hills was at the rate of 128 bushels per acre." 420 POTATO BREEDING AND SELECTION The year following, the progeny from the high-yielding strains averaged 96 bushels per acre, and that from the low-yielding 90 bushels. In 1909 the yields were, respectively, 115 and 120 bushels per acre. The average yield for the three seasons Avas at the rate of 104 bushels per acre from the high-yielding and 113 bushels from the low-yielding strain. In a more recent article Berthault* summarizes liis obser- vations upon sexual reproduction, which, roughly translated, are as follows : "1. That the form of tlie tuber is not a stable character in our cultivated varieties. 2. That the color, generally maintained through asexual propagation, sometimes varies. 3. That the depth of the eyes, a character almost always maintained in asexual reproduction, also offers, without apparent cause, examples of bud variation " Selection Methods. — While the ])receding discussion on "pota- to imi)rovenient by selection" has touched, in a more or less general manner, the processes of selection practised by those Avhose investigations have been cited, it has not dealt with specific methods, and their "modus operandi." Since the publication of the paper on "potato breeding and selection,"^" the views regarding the impor- tance of the "tuber-unit" as compared with the "hill selection" method of seed potato improvement, have been somewhat modified, as will be noted in a subsequent ])ortion of this chapter. The Tuber-Unit Method of Selection. — Tbe tuber-unit method of seed selection Avas first advocated by Webber^*, in 1908, since which time it has been rather widely practised by selectionists. It consists in planting selected tubers in such a way that the plants from each tuber will be definitely isolated from each of the other tuber-units. The tuber is cut lengthwise, through its central axis, into four as nearly equal parts as possible, aiming in all cases to cut through the cluster of eyes surrounding the terminal one. The quarters are planted consecutively, and a double space is left between the four units of each tuber, in order that they may be easily distinguished from one another. In selecting these tubers from the field or bin, the operator is supposed to select only those that conform to the type of the variety, that are free from all external diseases, and that weigh from 5 to 9 ounces. Smoothness of tubers and shallowness of eyes should be considered when making selections. No tubers should be taken that show the least tendency THE TTTBER-UNIT iMETHOD OF SELECTION 421 to running out, as indicated by a pointed seed or stem-end or a constricted centre, usually referred to as waisted. As many tubers should be selected as the grower thinks he can properly care for and make the necessary observations. Those selected should receive the usual treatment advocated for scab disinfection before being planted. While the original directions specify that the tubers should be cut into four equal longitudinal sections, our experience . has shown that, in the case of a long cylindrical tuber or even a moderately long tuber, as, for example, the Early Rose, Early Ohio, Beauty of Hebron and Burbank, it is much better to cut the two longitudinal halves crosswise than to halve them lengthwise. The reason for this is quite apparent. To divide the halved tuber lengthwise gives a long, slender seed piece which is much more likely to dry out or deca}^, according as to whether the soil is too dry or too wet, while the seed piece is germinating. To divide it crosswise gives a short, blocky seed piece which is, in every respect, better fitted to successfully withstand unfavorable soil conditions after it is planted. The claim that greater uniformity in the four seed pieces was secured by the longitudinal quartering of the tuber, has not been substantiated in our own studies. When the plants are about full grown, each set of fours should be carefully studied; and those which are most uniform, vigorous and healthy, and which conform most nearly to the type of the variety should be marked. Later in the season the tuber-units should again receive careful study for the presence of diseased or abnormal plants. The appearance of the plants at this time, or even at the earlier period, will no doubt present many marked dif- ferences between the various units. In all probability, as great variations will be noted as those shown in figures 224 to 229. At harvest time each unit, that is, each set of four plants, should be dug by hand and the progeny of each carefully examined. Many of those which were marked as promising from the appearance of the plants will be found undesirable from the tuber standpoint. They Avill either have given a light yield, or the tubers will be found lacking in uniformity as regards size or type, or both. Select those which have produced a reasonable number of marketable tubers Avith a small proportion of seconds and culls, and that are desirable in shape and color, bearing in mind that the heaviest producing units are not necessarily the most desirable ones to save. Place the tubers from each unit selected in separate sacks, and give each a 422 POTATO BREEDING AND SELECTION THE TUBER-UNIT METHOD OF SELECTION 423 Co- 424 POTATO BREEDING AND SELECTION field number. In labelling the sacks, use the perforated string tag mentioned in the handling of seedling potatoes. While it is not absolutely necessary, it is, on the whole, rather desirable to make a record of the number and weight of large and small tubers pro- duced by each "unit selected, because it is only by this means that one can really determine the true value of each selection. The following season, plant the progeny of each unit in a trial row by itself, but not, necessarily, on the tuber-unit basis. When the plants are full grown, they should again be studied, and all selec- tions which do not show a reasonable degree of uniformity of Fig. 226. — A weak and probably mosaic-infected tuber unit of the Norcross variety, 1911. From same lot of seed as the healthy unit shown in 225. Fig. 227 — 1912 product from five of the best tubers produced by the 1911 weak tuber unit. Primes on left, culls on right. plants, or that are lacking in vigor, or are diseased, should be marked for rejection. A second examination should be made toward the close of the growing season, and the same notes made as ill tlie preceding inspection. At harvest time, each progeny row should be dug separately, and only those which are productive, and reasonably uniform in size, shape, and conformity to varietal type should be saved. From this period on it should be possible to elimi- nate all but one or two of the very best strains, which should be groA\Ti on a field basis the following year in order to increase the seed stock. Hill Selection. — The only difl'erence between hill selection and the tuber-unit method is, that in the one case a start is made with the tuber as the unit, whereas in the other, the hill or individual plant is the unit. In hill selection the growing plants are carefully HILL SELECTION 425 scanned for the purpose of picking those which are most promising from the standpoint of health, vigor, and conformity to type (Figs. 23.0 to 236). The ideal time for the first examination is when the Fig. 229.— A weak mosaic-infected Irish Cobbler tuber unit. From same lot of seed as the healthy unit. plants are in bloom, or, in tlie event that the variety does not bloom, when the plants have reached their full size. As in the case of the tuber-unit plants, a later examination should be made in order to detect diseased or prematurely ripening plants. Just prior to harvesting the field, all the marked plants should be dug by 426 POTATO BREEDING AND SELECTION hand and the ])rogeny of each carefully examined. The same procedure should be followed from this point on as that outlined for the tuber-unit work. Fro. 230. — A field of Russef Burbank potatoes. The two taller plants in center indi- cated by the arrows are "run-outs" or degenerate plants. Carbondale, Col. (Sweet ranch.) Fig. 2.31. — Progeny from one of the "run-outs.' for seed stock. These tubers should never be used In general, the chief value of a large proportion of the selection work that is now carried on lies not so much in tlie fact that new strains have actually been secured, or that more productive strains have been developed, but rather that the varieties have been purified with respect to varietal mixtures, and to fungous pests of the vine MASS SELECTION 427 and tuber. It is also due in some measure to the elimination of the weak, unproductive plants, and of obscure, physiological troubles. If the selectionist is fortunate enough to secure desirable variations from the parent plant- that are transmitted from one generation of tubers to the other, a further gain has been secured. The work of Fischer would indicate that a high starch content is associated with shape of tuber. This factor is one which the ordinary man would be unable to detect witliout the aid of the chemist. The simpler phases of selection work may be suc- cessfully undertaken by any live up-to-date groAver who is sufficiently interested to estab- lish a seed plot. To those who do not care to practise selection on the individual plant basis, mass selection offers an invit- ing field. Mass Selection. — The first steps in mass selection are identical with those practised in hill selection. The field from which the selections are to be made is carefully gone over prior to harvesting the crop; all desirable looking plants are dug by hand and selections, based on the number, sliape, size, uniformity and quality of the tubers produced are made from them. At this point the processes cease to be identical, as in mass selection the tubers from the hundred or thousand or more plants chosen are all thrown together, and are subsequently planted and grown in much the same manner as the general run of seed stock would be handled. While mass selection does not permit of building up or isolating strains of a variety, it does very largely eliminate the weak, unproductive and diseased stock. The advantage of mass selection over hill selection is that it does away with, the necessity of handling a large number of selections separately, thereby very greatly lessen- ing the amount of work connected wdth such a method of seed improvement and for that reason will commend itself to many a grower who could not be induced to practise either of the two other plans. It is believed that mass selection is a step in the right direction and growers should be encouraged to adopt it. Fig. 232.- Burbank plant, lent seed stock. -Progeny from a good Russet These tubers will make excel- 428 POTATO BREEDING AND SELECTION The Seed Plot. — To those who are unwilling or unable to devote the necessary time involved in the practice of any of the selection methods discussed, there is still another way in which the quality of the seed stock may be maintained or actually improved. This method consists in planting a sui^cient number of rows in the ])otato field with well-selected seed, and then going through them carefully several times during the growing season for the purpose of detecting and removing any possible varietal mixtures, and all the weak and diseased plants. When harvested, the progeny from these rows should l)e stored in a separate bin and used for planting the commercial iield next 3'ear, after having again selected the best stock for tlie seed plot. The actual work involved in the conduct of such a seed plot is comparatively slight, while the increased yields '-^'\-^"x-?t-i, "v*-,^ are relatively large. It is not F ■-^'--- — Pn "' n ■ ir, in i -n. .1 I'u upcessary to be able to recognize set Uurbank plant, but tht- tubtrs.'aie nut as ])otato disCaSCS in OrdeP tO main- uniform in size and shape as those shown in . , 1 1 1. A n Fig. 232 and will not make as good founda- taill SUCh a Seecl plot. All any tion stock. grower needs to know is enough to be able to recognize plants that are not normal for the particular variety grown. If all abnormal plants are removed, the chances are more than even that most, if not all, of the diseased plants will be removed. The selectionist should always maintain a seed plot in which to test out his selections. As a rule, the seed plot should be planted at a later date than that of the commercial field (Figs. 235 and 236), with a view to securing somewhat immature and medium- sized seed stock. Seed Potato Development Work. — While in one sense this Mork does not emlwdy any new^ ideas, it is only recently that any attempt has been made to commercialize the results secured. It has long been known that different lots of seed of the same variety obtained from growers in various localities in a state, or even in a county, show surprisingly wide variations in yield. Until recently, no serious attempt had been made to take advantage of this situ- SEED POTATO DEVELOPMENT WORK 429 ation by securing and disseminating these high-yielding strains. Prof. W. S. Blair, Superintendent of the Dominion Experimental Farm of Kentville, N. S., was one of the first investigators to call our attention to this subject, when he mentioned the results of some studies upon a number of strains or lots of the Garnet Chili, Green Mountain and Irish Cobbler potatoes which he had carried on under the direction of W. T. Macoun, the Dominion Horticulturalist of Canada, dur- ing the years 1915 to 1917, and reported by Macoun in 1918.^* The difference between the higli- ost- and lowest-yielding strains of eight lots of Garnet Chili ])otatoes in 1915 was 204 liushels. In 191G the difference in yield of the same stocks was 144 bushels; and in 1917 it was 225 bushels. Ten lots of Green Mountains, tested in 1916, showed a maximum variation of 1321/2 bushels; while in 1917 the difference was 147 bushels per acre. In the 17 lots of Irish Cobbler, tested in 1916, there was a variation of 142 bushels; while in 1917 the dif- ference amounted to 172 bushels per acre. Fig. 234.— ProKeny of a single plant Somc Unreported experimcn- of the Russet Burbank potato. Mother tu- ,,,-,• • m-in l -in.^n • ber at apex. Grown bv the Crystal River tal StudieS in 1919 and 1920 m Land Co., Carbondaie. Col. Wisconsin and Minnesota simi- lar to those conducted at Kentville, Nova Scotia, fully corroborate the Canadian results, thereby justifying a growing conviction that this field of experimentation offers greater possibilities for imme- diate results than does the tuber-unit or hill selection methods. The location of high-yielding strains by this method of comparison as to the productivity and general desirability of given strains 430 POTATO BREEDING AND SELECTION QUESTIONS ON THE TEXT 431 enables the experimentor to immediately place a goodly quantity of this varietal strain in the hands of those who are interested in the production of high grade seed potatoes. Furthermore, it is reasonable to assume that more certain and lasting results should be secured from the use of such a strain for the development, through selective processes, of a still more desirable seed stock. QUESTIONS ON THE TEXT 1. Give the author's definition of breeding and selection. 2. What are the limitations in breeding? 3. What are the limitations in selection? 4. When did potato breeding begin to assume importance in America and Europe? 5. W^ith the exception of Goodrich, what was the chief consideration in the minds of American potato breeders regarding new varieties? C. Name some of the more prominent of the nineteenth century American potato breeders. 7. What was Goodrich's notion concerning the effect of long continued asexual propagation upon the vigor of the potato plant? 8. What remedy did he propose? What stocks did he use? 9. What was the most important variety he produced ? 10. How many seedlings did he grow? 11. In what respect was Goodrich's type of potato breeding lacking? 12. What influence did Goodrich exert through the agency of the press? 13. By whom and at what date was the Early Rose originated? Give its parentage. 14. What other varieties did Bresee originate? 15. In what way does Pringle's work rise above that of most other American potato breeders? 16. At what price per pound did Pringle contract to produce hybridized potato seed? 17. Give substance of quotation from Pringle's letter to Fenn. 18. Name some of the varieties originated by Brownell. 19. Name some of Rand's seedling productions. 20. Mention some of the varieties originated by Alexander. 21. What varieties did Gleason and Heffron originate? 22. Give a brief resume of the origin of the Burbank Seedling. 23. How does Burbank's achievement compare with that of Goodrich's? 24. In what way did Goodrich's successors profit by his work ? 25. What variety did Alfred Reese produce? Wliere is this variety most extensively grown at present? 26. What varieties did E. L. Coy originate? Give parentage of his Early Beauty of Hebron. 27. Review the work of Carman. 28. What varieties did Bovee produce? 29. What varieties did Craine give us? 30. What varieties did Van Ornam originate? 31. Who was Great Britain's pioneer potato breeder? Review his work. 32. Review letter of Robert Fenn to Pringle, -January 27, 1876. 33. When did Fenn make his first crosses and what varieties did he use? 432 POTATO BREEDING AND SELECTION 34. Give the parentage of Clark's Magimni Boiuini and some of the charac- teristics it possessed which lielped to make it famous. ;];"). Give the name of the variety that made Archibald Findlay so famous as a plant breeder. 36. What name stands out most prominently among the plant breeders of France? 37. What did Wilhelm Richter accomplish in the improvement of the potato in Germany? 38. Compare catalogue descriptions of the new potato introductions of the present period with those from 1857 to 1890. 39. How do European activities in potato breeding in the twentieth century compare with those of the nineteenth century? 40. At what prices did early productions sell? 41. What are the difficulties confronting the potato breeder at the present time? 42. What does East say about the flowering habits of our commercial varieties of potatoes? 43. How does the author's opinion compare with East's deductions on the flowering habits of potato varieties? 44. How do varieties dilTer in production of viable pollen? 4."). What was the character of the four American varieties found to produce a dependable supply of viable pollen? 46. What two foreign varieties are mentioned as being good pollen parents? 47. What assertion did Salaman make with reference to male sterility? 48. Describe the structure of the pistil and the stamens of the potato flower. 49. W^hat relation between color of stamens and development of pollen? 50. Give relation between turgidity and male sterility. 51. What does the author say regarding extreme turgidity of the stamens bordering on the coriaceous? 52. What should be the first and second steps in artificial cross-pollination? 53. What is the proper stage at which to emasculate potato flowers? 54. Describe method employed by the author in emasculation. 55. What covering is recommended to inclose the emasculated flowers? 56. What particular advantage is there in inclosing foliage with the flowers ? 57. What interval should usually be allowed between emasculation and the application of pollen? 58. What methods of collecting and applying pollen and recording were adopted by the author? 59. How long does it usually take before one can determine whether the cross is a success or failure? GO. When should the seed balls be gathered? How kept? 61. ^Vhat is the simplest method of removing the seeds from the seed balls or berries? 62. What directions are given for growing seedlings? 63. How long does it take good potato seed to germinate? 64. At what distance should the seedlings be spaced in the open field? 65. What notes should be taken on each individual plant when harvesting and how should those saved ))c recorded? 66. How should the subsequent testing of the seedlings be conducted? 67. How many years should a seedling usually be tested before introducing it? What exceptions are noted? 68. What are the variations sought in selection? 69. What is the tuber-unit method of selection? REFERENCES CITED 433 70. What is the hill selection method? In what respect does it diller from the tuber-unit method? 71. What is meant by mass selection? How does it differ from hill selec- tion? Is it a desirable practice? 72. What other method of seed improvement is open to the grower? 73. How does it compare with the preceding methods? 71. What is meant by seed potato development work? QUESTIONS AND EXERCISES SUGGESTED BY THE TEXT 1. What is the usual custom of local growers regarding seed selection of potatoes? 2. What improved methods are tried by the best? 3. What results have been secured locally from tuber-unit selection? 4. What from hill selection? 5. When harvesting potatoes, weigh the yields of some of the best and poorest hills. 6. If possible, compare the relative yields in a hill-to-row test. References Cited 1. Andersox, Jas. 1795. On potatoes and their culture. Report of the committee on the culture and use of potatoes: 107-133, G7-t. Brit. Ed. Agr. Bpt. 1705. 2. Anonymous. 1868. American Agriculturist. A large price for pota- toes. 27: 130, April, 1868. 3. Beecher, H. W. 1870. The potato mania. Best's Potato Book (Utica, N. Y.) 1870: 1-96. 4. Berthault, p. 1911. Recherches botaniques sur les varieties cul- tivees du Solanum tuberosum. Awn 8ci. Agron. ser. 3, 6th. ann. 2: 1-59, 87-143, 173-216, 248-309, 1911. 5. CARRiicRE, E. A. 1865. Production et Fixation des Varieties dans les Yegetaux: 1-72, Paris, 1865 (see p. 40-41). 6. Dean, Alex. 1890. Potato improvement during the past twenty-five years. Jour. Roy. Hort. Soc. 12: 45, 1890. 7. East, E. M. 1908. Technic of hybridizing the potato. Proc. Soc. Ilort. 8ci. (1907): 35-40, 1908. 7a. 1910. The transmission of variations in the potato in asexual reproduction. Conn. (New Haven) 8ta. Rpt. 1909-1910: 119- 160, 1910. 8. Eustace, H. J. 190.'). An experiment on the selection of "seed" potatoes: Productive versus unproductive hills. Proc. Soc. Hort. 8ci., 1903-1904: 60-62, 1905. 9. Fenn, R. 1876. Looking Back. Jour. Hort. d Cottage Gard. 8: 99-100, 1876. 10. Fisher, M. 1900. Kartoffelzuchtungs und Anbauversuche. Fuhlings Landw. Ztg. Jahrg. 49: 301-307, 343-352, 369-372, 1900. 11. GoFF, E. S. 1885-1886. Experiments with tubers from productive and unproductive hills. A^. Y. {Geneva) Sta. Third Ann. Rpt., 1884: 301-305; Albany. Fourth Ann. Rpt., 1885: 232-235; Albany, 1886. 12. Goodrich, C. E. 1857. Raising seedling potatoes. The Horticulturist, 12: 276, 1857. 12a. -1863. The Garnet Chili potato. Co. Gent., 22: 155, 1863. 13. Hallet, F. p. 1882. Food plant improvement. Nature, 26: 91- 94, 1882. 28 434 POTATO BREEDING AND SELECTION 14. ilACOUX, W. T. 1918. The Potato in Canada. Dom. Can. Cent. Exp. Farms Bui., 90: 21, 1918. 15. Salaman, R. N. 1910. Male sterility in potatoes a dominant Men- delian character. Jour. Linn. iioc. (London) Bat., 39: 301- 302, 1910. 15d. 1910. The inheritance of color and other characters in potatoes. Jour. Genetics, 1: 7-46, 29 pis., 1910 (see p. 8). 16. Skinner, R. P. 1914. The utilization of potatoes in Europe. U. /S'. Dept. Com. Spec. Consular Rpt. No. 64: 1-44, 1914 (see p. 10). 17. Stuart, W. 1915. Potato breeding and selection. IJ. H. Dept. Agr. Bui, 176: 1-35, May, 1915. 18. Waid, C. W. 1907. Results of hill selection of seed potatoes. Am. Breeders' Ass'n. Third Ann. Rpt.: 191-198, 1907. 19. Webber, H. J. 1908. Method of improving potatoes. N. Y. {Cornell) Sta. Bui, 251: 322-332, 1908. 20. Wright, W. P., and E. J. Castle. 1913. Pictorial Practical Potato Growing (see p. 9). CHAPTEE XXII CLASSIFICATION AND DESCRIPTION OF COMMERCIAL VARIETIES Within the past few years a distinct advance lias been made in the classification of American varieties of potatoes into groups or classes having certain distinctive characters of vine or tuber. This step was made necessary through an increasing tendency on the part of some seedsmen to give old varieties new names, thereby adding greater confusion to that which ordinarily obtained. Al- though but a few years ha^■e elapsed since the group classification was really undertaken in the United States, it has already exercised a very beneficial effect upon the introduction of new varieties. In fact, some of the seedsmen have modified their list of seed potato offerings so as to comply in a very acceptable manner with the classification system. The Putsche and Vertuch Classification. — The first pub- lished attempt at classification that has come to our attention is that by Putsche and Vertuch* in their monograph of the potato, in which they present a classification system (p. 10) which, though crude, indicates the desire, even in those early days, for some method by which the varieties could be grouped. This classification is based on the following parts of the plant: (1) plant (number and size of stems); (2) color of blossom; (3) method of propa- gation and source of stock; (4) shape and form of the tubers; (5) smoothness or roughness and thickness of the skin; (6) color of skin; (7) size of tubers; (8) character of the flesh; (9) taste of the flesh; (10) productiveness; (11) position of tubers in the soil; (12) period of maturity (early or late). The authors com- ment on their scheme of classification with reference to the first eleven divisions as follows : " It is scarcely necessary to observe that all these classifications are based, upon variable quantities, which depend upon soil, position, climate and cultivation, and therefore are insufficient for a complete diagnosis. A less variable, more positive, and surer division is according to the ripening period." Those ripening between the first and middle of July to the last of August were classed as earlies, while those ripening after the first of September were called late or main crop varieties. 435 436 DESCRIPTION OF COMMERCIAL VARIETIES The explanation given l)y the authors is a sufficient criticism of this scheme of classification to make further comment unneces- sary, as it must be evident to all that it is an unworkable one. Lenne's Classification. — The next classification system that has come to our attention is that worked out from varieties grown on the trial field of the Eoyal State Nursery near Potsdam, in Prussia, and reported by Director General Lenne.'' This classification is based on the color of the skin, the shape of the tuber and the color of the flesh. In this scheme fifteen combinations or groups were secured, viz. : I. Yellow-skinned, rounded, yellow-fleshed varieties. II. Yellow-skinned, rounded, white-fleshed varieties. III. Yellow-skinned, elongated, yellow-fleshed varieties. I\'. Yellow-skinned, elongated, white-flcshed varieties. V. Yellow-skinned, kidney-shaped, yellow-fleshed varieties. VI. Yellow-skinned, kidney-shaped, white-fleshed varieties. \'II. Eed-skinned, rounded, yellow-fleshed varieties. VIII. Red-skinned, rounded, white-fleshed varieties. IX. Red-skinned, elongated, yellow-fleshed varieties. X. Red-skinned, elongated, white-fleshed varieties. XI. Red-skinned, kidney-shaped, yellow-fleshed varieties. XII. Red-skinned, kidney-shaped, white-fleshed varieties. XIII. Blue-skinned, rounded, yellow-fleshed varieties. XIV. Blue-skinned, rounded, white-fleshed varieties. XV. Blaekish-blue skinned, rounded, violet-fleshed varieties. The number of varieties classified under each of these fifteen groups were as follows : Group I. — 71 varieties. Group IX. — ^^ varieties. Group II. — 22 varieties. Group X.— 10 varieties. Group III. — 12 varieties. Group XI. — 4 varieties. Group IV.— 3 varieties. Group XII. — 1 variety. Group V. — 4 varieties. Group XIII. — 5 varieties. Group VI. — 4 varieties. Group XIV. — 9 varieties. Group VII. — 11 varieties. Group XV. — 2 varieties. Group ^^III. — 9 varieties. Vilmorin's Classification. — The third classification scheme, chronologically, is that of Vilmorin^^ who in 1882, and again in 1886 and 1903, published the results of many years' observations of a very complete collection of potato varieties. These varieties were grouped into 13 classes in 1886, and the 13 classes were further subdivided into 30 sections. In the 1903 edition only 9 classes were made; biit these 9 classes were subdivided into 40 sections. Vilmorin's classification is considerably more elaborate than that of Lenne's previously given, the classes being based on the color KOHLER'S CLASSIFICATION 437 and shape of the tubers, and that of the sections on the color, shape and size of the tubers, the depth of the eyes, the color of the sprouts in the dark, and the color of the flowers. The 9 classes are as follows : 1. Yellow, round. 4. Flesh-colored, oblong. 7. Rose or red, long. 2. Yellow, oblong. 5. Rose or red, round. S. Violet-colored. 3. Yellow, long. 6. Rose or red, oblong. !). Streaked (mottled). The varieties included in class 1 are divided into ten sections, of which section 3 will serve as an illustration. Section 2. Tubers, yellow or white, round; flowers colored, often abundant ; flesh white ; sprouts violet, more or less colored, Kohler's Classification. — One of the first attempts at group classification in the United States is that of Kohler, who, in March, 1909, published the first results of his studies on the classi- fication of potato varieties. In explanation of the classification of varieties Kohler* says : " Varieties of potatoes may be classified into groups, artificially, by considering the tubers alone, and, naturally, by considering the entire plant. There is in many cases, and possibly all, a definite relation be- tween type of tuber and type of plant, which means that the two methods of classification merge into each other ... .Varieties belonging to closely related groups often merge into each other and make it difficult to draw the line between the groups .... The plan is to group together varieties having similar plants, and under these groups subdivide according to the shape of the tuber, and under tuber subdivide according to color, thus : "■ I. Characteristics of vines. A. Shape of tubers. B. Color of tubers." Kohler divided the varieties in the collection which he studied into eleven groups as follows : I. Tuberosum. VII. Early Michigan. II. Rural. VIII. Milwaukee. III. Endurance. IX. Russet. IV. Seedling B. X. Ohio. V. Green Mountain. XI. Early Market. VI. Carman. His plan of subdivision of the groups can be best illustrated by giving that of group I. I. Tuberosum. A. Tubers roundish. B. Tubers somewhat elongated to about medium in length. C. Tubers long. 438 DESCRIPTION OF COMMERCIAL VARIETIES 111 a later publication/* April, 1910, Koliler retained the same number of groups, but substituted new names for four of them. Some change was also made in the order in which they were listed as will be noted from a comparison of the two lists as presented below. List I. List IL I. Tuberosum Tnlierosum. II. Rural ■ •■ • Wohltmann. III. Endurance Rural. IV. Seedling B Endurance, V. Green Mountain Factor. VI. Carman Sharp's Express. VII. Early Michigan Green Mountain. VIII. Milwaukee Michigan. IX. Russet Russet. X. Ohio Ohio. XI. Early Market Cobbler. A careful review of Kohler's classification studies cannot fail to impress the reader with the extent of the work performed ; and, if one keeps in mind the fact that he was blazing a new trail, as it were, so far as an American classification was concerned, we must concede that a very fair beginning was made. His work has been a source of helj) to those who followed him. Ballou's Classification, — Ballou's classification,^ which ap- peared about the same time as Kohler's second one, describes seven groups. The author explains that in this classification he has reduced the groups to the least possible number, 7, and that only a few of the many varieties that might easily be included in each of the groups are mentioned. He further states that the classification is based principally upon the similarity of the character of the tubers of the difi'erent varieties, without s])ecial consideration of the similarity of the plants of each ; but that in many cases, however, there is a similarity of plants as well as tubers. The seven groups in Ballou's classifi- cation are : Triumph. Green Mountain. Early Market. Seneca Beauty. Early Ohio. Rural Xew Yorker. Early Rose. Milward's Classification. — In 1912, Milward" classified the commercial potato varieties of Wisconsin into three groups which were considered to represent distinctive types. These were called STUART'S CLASSIFICATION 439 the roiHid white, the long white, and the rose groups of potatoes. The first two groups are classified as follows: Group 1. Round white. — Tubers: Round to oval and slightly flattened. Surface generally netted. Skin white, and flesh white. Flowers: White or purple. Group 2. Long white. — Tubers: Long oblong in shape and sometimes flattened. Skin and flesh white. Fitch's Classification, — Two years later Fitch-'^ descril)e(l seven groups of American varieties of potatoes, viz., the Eural, Early Ohio, Irish Cobbler, Green Mountain, Burbank, Peerless or Pearl, and Bliss Triumph. The description of each of these groups is good, and is well worth the careful study of those interested in the characteristic appearance of the members of each of them. Photographs representing the range of variation in tuber shape within each group enable the student to acquire a fairly good con- ception of the range of variation in the form of the tubers. Kranz's Flower-stalk Classification. — Kranz^ has recently suggested another character for potato identification, viz., the position of the flower stalk. lie found that in the Irish Cobbler, Early Eose, and Early Ohio the flower stalks are borne in the axil formed by a leaf and the main stalk. The Triumph, Burbank and Green Mountain bear their flower stalks on the petiole of the leaf. In the Eural group the flower stalks are borne on the main stem, usually at a slight distance from the axil of the leaf. Snell's Classification. — This classification, published in 1931,'^ is based on date of ripening, color of tubers, and plant, stem, leaf and flower characters. The main classification, however, is based on the first two characters. The author divides German potato varieties into two classes or sections : I. Early or medium early. II. Late or medium late. Four groups of potatoes are assigned to the first division, while the late or medium late varieties are subdivided into two sections : (a) those with white or blue tubers, and (b) those with red tubers. The first subdivision includes three groups and the second two. The description of the tubers in each of these groups is greatly facilitated by a colored plate. The flower and sprout characters are shown on plate 3. Stuart's Classification.— In March, 1915, Stuart^^^ published a system of classification somewhat similar to that of Fitch's, 440 DESCRIPTION OF COMMERCIAL VARIETIES although the latter's bulletin did not come to his attention until page proof of bulletin 176 was being corrected, when a footnote was inserted, mentioning the Iowa publication. In this classifi- cation eleven groups are recognized. These were based on studies extending over a period of ten years, in which the author had an opportunity to study the behavior of varieties from Maine to California and from New Jersey to Florida. In dis(;ussing his proposed S3'stem of classification he says (p. 3) : " In presenting the following classification key and group description, no one realizes more clearly than does the writer that there is still much to be desired. It is hoped, however, that this classification will serve as a starting point upon which to base further studies. It is quite probalile that the groups here presented will, in many cases, resolve themselves into one or more sub-groups or sections which are based on finer distinctions than those given for the group as a whole. It is equally certain that some new groups will have to be made in order to include those varieties which do not, at present, seem to fit into any of the classes now proposed." " The value of stiidying varietal groups cannot be too strongly emphasized. When the varieties fitting into such groups are planted in adjacent rows the comparative differences, as well as similarities, are more easily noted. The recognition of old varieties xmder new names is almost certain to result from such a study, and should tend to discourage the present practice of some of the seedsmen who manufacture new varieties out of old ones." The following classification key has been found very helpful in studying potato varieties. It is not an exact reproduction of bulletin 176, some minor changes having l)een thought desirable. In all other respects the two keys are identical. Classification Key (Stuart's) (The color values are based upon the chart puldished by the French Chrysanthemum Society, Paris, 1905). Group 1. Cobbler. — Tubers: Roundish to roundish-flattened or slightly oblong, stem-end usiially deeply recessed or notched; skin creamy -white. (Plate I-A). Sprouts: Base, leaf scales and tips slightly or distinctly tinged with roddish-violet or magenta. In some cases the color is nearly, if not entirely, absent. (Plate I-A). Flowers: Light rose-purple, under intense heat may be almost white. Plants flower very profusely in some sections. (Plate I-A'). Group 2. Triumph. — Tubers: Eoundish to roundish-fiattened ; skin solid red or magenta in the case of the Triumph to creamy-white with more or less numerous splashes of red or carmine in the case of Noroton Beauty; and white with faint to pronounced coloring in the eyes in the case of White Triumph; maturing early. (Plate I-B). Sprouts: Base, leaf scales and tips more or less deeplv suffused with reddish-violet. (Plate I-B). PLATE I. A — Tuber of the Irish Cobbler showing color of skin and of sprout. A'— Flower truss of the Irish Cobbler showing size and color of buds and ex- panded blossoms. B — Tuber of the Triumph variety showing typical appearance of the skin and sprouts. B' — A typical flower cluster of the Triumph showing paucity of individual flowers and evidences of premature dehiscence, or dropping off of bloom. C — A typical tuber of the Pearl variety. Note deep stem -end recession and heavy shouldering of tuber. C' — A flower truss of the Pearl. True-to-type Pearls seldom show more than two to three expanded flowers in any one cluster and always present evidence of the premature dropping of flower buds before opening. PLATE II. D — A representative Early Rose tuber showing skin and sprout characters. D' — An average flower truss of the Early Rose. Note profusion of bloom. E — A well shaped Early Ohio tuber showing characteristic skin and sprout coloration. E' — An average flower truss of the Early Ohio. Note paucity of bloom and light color of stamens. F — A desirably shaped Beauty of Hebron tuber. Note unevenness of skin coloration and creamy white appearance of skin surrounding the eyes. F' — A flower truss of the Beauty of Hebron. Note intermediate stage between Early Rose and Early Ohio in number of blooms. STUART'S CLASSIFICATION KEY 441 Flowers: Very light rose-purple, rather small, flowers sparingly. (Plate I-B'). Group 3. Early Michigan. — Tubers: Oblong or elongate-flattened; skin white or creamy-white, occasionally suffused with pink around bud-eye cluster in Early Albino. Sprouts: Base light rose-purple; tips creamy-white or light rose-purple. Flowers: White, rather profuse. Group 4. Rose. — Tubers: Elongate-flattened to spindle-shaped flattened in section 1, or oblong-flattened in the case of section 2; skin flesh-colored or pink; bud- eye cluster deep magenta, (Plate II-D) ; in the case of the White Rose the skin is white. Sprouts: Base and internodes creamy-white to deep rose-lilac; leaf scales and tips cream to rose-lilac. (Plate II-D). Flowers: White; blooms fairly abundant. (Plate II-D'). Group 5. Earli/ Ohio. — Tubers: Round-oblong, or ovoid, generally slightly flattened though not always; skin flesh-colored or light pink, usually with numerous medium-sized, rather conspicuous russet dots or lenticels. (Plate II-E). Sprouts: Base, leaf scales and tips more or less deeply suffused with carmine-lilac, to violet-lilac or magenta. (Plate II-E). Flowers: White; moderate bloomer. (Plate II-E'). Group 6. Hebron. — Tubers: Elongated, and distinctly flattened, sometimes spindle-shaped; skin creamy-white, more or less colored with flesh color, or light pink. Creamy-yellow around eyes. (Plate II-F). Sprouts: Base creamy-white to light lilac; leaf scales and tips pure nuiuve to magenta, color often absent. (Plate II-F). Flowers: White; moderately free bloomer. (Plate II-F'). Group 7. Biirbank. — Tubers: Long, cylindrical to distinctly flattened, inclined to be somewhat spindle-shaped; skin white to creamy-white (Plate III-G), smooth and glistening or slightly netted, or deeply netted and dark, russet in the case of section 2. (Plate III-G'). Sprouts: Base creamy-white or faintly tinged with magenta; leaf scales and tips usually lightly tinged with magenta but quite often color is absent. (Plate III-G and G' ) . Flowers: White, moderate bloomer. (Plate III-G"). Group 8. Green Mountain. — Tubers: Moderately to distinctly oblong, usually broad, flattened with blunt ends; skin a dull creamy or light russet color; sometimes rather heavily netted especially toward the seed end. (Plate III-H). Sprouts: Section 1. — base, leaf scales and tips creamy -white. (Plate III-H) ; section 2. — base usually white, occasionally tinged with magenta; leaf scales and tips tinged with lilac to magenta; usually color is very faint. Flowers: White; blooms profusely. (Plate III-H'). Group 9. Rural. — Tubers: Broadly round-flattened to short oblong, or distinctly oblong- flattened; skin creamy-white, usually smooth, but sometimes lightly netted; or heavily netted, and russet color as in section 2. (Plate III-I and I'). Sprouts: Base dull white; leaf scales and tips violet-purple to pansy- violet. (Plate III-I). 442 DESCRIPTION OF COMMERCIAL VARIETIES Flowers: Central portion of corolla deep violet-purple with the color growing lighter toward, the outer portion ; five points of corolla white or nearly so. Moderate bloomer. (Plate III-I" ) . Group 10. Pearl. — Tubers: Round-flattened to heart-shape flattened, itsually heavily shouldered due to deep recession of stem; skin dull white or buff in section 1, (Plate I-C), distinctly russet or brownish color in section 2, or a deep bluish-purple with occasional creamy-white splashes, usually around the eyes in section 3. Sprouts : Sections 1 and 2. — base, leaf scales and tips usually faintly tinged with lilac, (Plate I-C); section 3. — base, leaf scales and tips vinous-mauve. Flowers: White; blooms very sparingly. (Plate I-C). Group 11. Peachbloic. — Tubers: Round to round-flattened or round-oblong; skin creamy-white, splashed with crimson or solid pink; eyes bright carmine. Includes some early-maturing varieties. ( Plate IV- J, J' and K ) . Sprouts: Base, leaf scales and tips more or less suffused with reddish- violet. (Plate IV- J and K). Flowers : Purple, usually rather free bloomers. ( Plate IV-J" and K' ) . Group 12. Up-to-Date. — Tubers: Oblong-flattened to somewhat obovate-flattened ; skin creamy- white, moderately netted or nearly smooth. ( Plate IV-L ) . Sprouts: Base dull white, leaf scales faintlv to distinctly tinged with light magenta. (Plate IV-L). Flowers: Rose-purple; moderate to fairly profuse bloomer. (Plate IV-L' ) . Pistil: Usually short, thick and curved with enlarged stigma. The last group (12) has been added to accommodate a few varieties of Scotch-Englisli origin which are being grown to some extent in the United States and to a greater degree in Canada, and from which there seems to be springing up, or emanating, certain varieties presumably of American origin which have been more or less widely disseminated. Whether these varieties are simply the Up-to-Date or Factor re-named is difficult to determine, but in any event they must be considered members of a group which, in certain sections of the New World, may become the leading commercial type of potatoes grown. In regard to the naming and describing of the groups the bulletin says {I.e. p. 5) : "In deciding upon the name by which each group shall be known, an attempt has been made to select that of the variety which seems most nearly to represent the group as a whole and which, at the same time, is most widely known." The classification key presented is too brief to do other than to serve as a simple means of placing a variety in the group to which it seems related. The more complete description, which follows^ is in a large measure a reproduction of that published by PLATE III. G — A well shaped tuber of the Burbank variety showing skin and sprout coloration. G'— A fair specimen tuber of the Russet Buibank. Note deep russet color and heavy netting of skin. G" — Flower truss of the Burbank potato. Note length ol petals of unopened buds and hght color of stamens. H — A good specimen tuber of the Green Mountain variety. H' — A small flower truss of the Green Mountain potato. Note deep orange- yellow color of stamens. Compare shape of unopened buds with those of the Burbank. I— A show tuber of the Rural New Yorker No. 2 (Rural Group). Note shal- low eyes and violet color of tips of sprouts and leaf scales. I' — A good specimen of the Russet Rural potato. I" — A typical flower truss of the Rural Group of potatoes. Note color of petals of unopened buds and of corolla of expanded flower. I'" — A portion of the stem of a Rural New Yorker No. 2 plant showing coloration of the epidermis. PLATE IV. J — A McCormick tuber somewhat better than the average shape, showing normal skin and sprout coloration. J'— A fair tuber specimen of the White McCormick. Note absence of color in skin and sprouts. J" — An average-sized flower truss of the McCormick variety. K — A good specimen tuber of the Perfect Peachblow (Red McClure) variety. K' — Flower truss of the Perfect Peachblow. L — A representative tuber of the Up- to- Date variety of potato. Note shal- lowness of eyes and coloration of sprouts. L'— Flower truss of the Up-to-Date variety. Note similarity of color of unopened buds to that of the McCormick. DESCRIPTION OF GROUPS 443 Stuart {I.e. p. 5). Such changes as occur are the result of a more intimate knowledge of the group as a whole and the type variety in particular. Description of Groups. Group i. — The Cobbler group represents a class of early-maturing potatoes. The Irish Cobbler C D Fig. 237. — Four views of a well-shaped though rather shallow-eyed Irish Cobbler tu- ber. A — upper: B — lower; C — seed end; D — stem end view. is by far the most extensively grown variety of this group. It is now, and has been for a number of years past, the leading com- mercial early market variety in the Atlantic Coastal Plain region from Long Island to Georgia. It is also grown extensively in the 444 DESCRIPTION OF COMMERCIAL VARIETIES Louisville, Kentucky, district. Large quantities of Irish Coljljler are also grown in some of the late or main-crop producing sections of the North, notably of northern Maine and New York and ni certain localities in Michigan, Wisconsin and Minnesota. In the northern sections it is principally grown for the purpose of sup- plying seed to the southern truck grower. Figures 237 and 238, and n. 1-A illustrate different types of potatoes belonging to group 1. Description. — Matures early. Vines medium to above medium in size with somewhat spreading habit of growth. Stems dark green, stocky and rather short-jointed. Leaves large, flat or nearly '|g(r t Fig. 238. — Two representative Irish Cobbler tubers showing averatie depth ot bud eyes. SO, more or less flaccid in northern Maine when grown under optimum conditions, but much smaller, as a rule, in the Central West; they are medium dark green in color. Flowers numerous, rather large, light puriDle- or rose-lilac ; under intense heat the color may be practically unexpressed. Tubers roundish to roundish- flattened or slightly oblong-flattened, the stem-end usually rather deeply notched giving a rather shouldered appearance to the base of the tuber (PI. 1-13). Eyes medium in number, varying from shallow to rather deep, particularly in the bud-eye cluster, (PL II). Skin usually smooth, but sometimes fairly well netted, as in the case of the Potentate, light creamy-wliite in color. Sprouts stout and rather stubby, vary in color at the base from a very faint reddish-violet or magenta to a perceptible coloration; tlie tips and leaf scales are usually tinged with the same color. Occasionally the color is almost, if not entirely, absent. GROUP 2. TRIUMPH 445 The following varieties have been classed in the Cobbler grouj) and, to all intents and purposes, most of them are identical. Early Beauty. Early Dixie. Early Eureka. Early Petoskey. Early Standard. Early Victor. Early Waubonsie * Extra Early Eureka. Group 2. Triumph. — This group includes the earliest named varieties grown in the United States. The Triumph is the leading commercial variety of the group, as well as its oldest memher. It First Early. Flourball. Happy Medium. Irish Cobbler. Irish Daisy. New White Victor. Potentate. Trust Buster.* Fig. 239. — A well-shaped and good type Triumph tuber natural size. is chiefly grown in the States of Florida (southern part), Alabama, Mississippi, Louisiana, Texas, Oklahoma, Arkansas and portions of Tennessee, in which sections it is the leading truck crop variety. In the North, it is grown most extensively in Maine, Wisconsin, Minnesota and Nebraska, in order to supply the southern grower with seed stock. Ordinarily it is not grown in the North primarily for table stock. Description. — Very early. Vines medium to small, fairly compact, not much branched. Stems short, stocky, dark green. * Classified by Prof. A. L. Dacy, Exp. Station, Morgantown, W. Va. 446 DESCRIPTION OF COMMERCIAL VARIETIES U**^., > GROUP 2. TRIUMPH 447 448 DESCRIPTION OF COMMERCIAL VARIETIES Flowers usually fevv' in number, small in size, and of a rose-lilac color. Tubers roundish to roundish-flattened with stem-end slightly to distinctly shouldered (Figs. 239 to 241 and PL I-B). Eyes medium in number, rather shallow ; bud-eye cluster generally more or less depressed. Skin creamy-white, generally with pink eyes, and occasionally with splashes. — White Triumph. — with few or many splashes of crimson as in the Quick Lunch and Noroton Beauty; or solid red, or occasionally solid red splashed with crimson, as in the Triumph. Flesh a creamy-white. Sprouts have base, leaf scales and tips more or less deeply suffused with reddish-violet. The varieties assigned to the Early Michigan group are as follows: Early Prospect. Quick Lunch. Honeoye Rose. Triumph (Bliss's). Noroton Beauty. White Triumph. Wood's Earliest. Of the above list of names Early Prospect is perhaps the most flagrant example of a recent occurrence of the re-naming of an old and easily recognized standard commercial variety, as it is a simon-pure Trium})h. Honeoye Rose, Noroton Beauty, Quick Lunch and Wood's Earliest are identical. The varieties of this group seem to be peculiarly susceptible to the mosaic disease. Group 3. — The Early Michigan group has been provided for the purpose of accommodating certain early-maturing white-skimied varieties which, owing to the character of their vine growth, color of flowers, and color and shape of tubers do not fit into either of the two preceding groups or of any of the succeeding ones. The members of this group are most closely related to the Green Moun- tain class of potatoes. Commercially speaking, they are not very extensively grown but apparently have a place in certain localities in the Middle West as, for example, around Chicago and Detroit. Description. — Medium early to mid-season. Vines of medium size. Flowers fairly abundant, medium size, white. Tubers oblong- flattened to elongate-flattened or ovoid (Figs. 242 and 243). Eyes numerous, medium size and depth. Skin white or creamy- white or, in the case of the Early x4.1bino, occasionally suffused with pink around the bud-eye cluster. Sprouts light rose-purple at the base, with the scales and tips creamy-white or tinged with light rose-purple. The varieties assigned to the Early Micliigan group are as follows: Dew Drop. Early Puritan. Early Albino. Ehnola. Early Harvest. E.xtra Early Sunlight. Early Michigan. GROUP 3.— THE EARLY MICHIGAN 449 29 i50 DESCRIPTION OF COMMERCIAL VARIETIES Group 4. Rose. — In point of numbers, the Eose group is one of the largest. With the exception of the Extra Early White Eose, all of the varieties in this group have pink or flesh-colored tubers and all, save the late Eose, may be classed as early or mid-season varieties. The Early Eose is perhaps more widely grown than any other variety, outside possibly of the Early Ohio; but neither it nor the group as a whole can be regarded as an important com- mercial factor in the potato industry of this country, because in >| Fio. 244. — Tuber on left reproduced from one of the original cuts used to illustrate the Early Rose variety, Group 4. Note prominence of the eyes. Right from the photograph. no locality except Florida are they extensively grown at the present time. However, the group is an interesting one, as the Early Eose, in a sense, represents the fountain-head, as it were, of many of our present day varieties belonging to other groups. In order to include certain varieties, which apparently belong to this group, but which differ somewhat in growth of plant, shape of tuber, and color of skin and sprouts, it has been found necessary to make two sections, to the first of which are assigned the true Early Eose types. In this connection it is desired to call attention to the fact that in Department Bulletin 176, previously referred GROUP 4. ROSE 451 to, a third section was provided in this group, in order to include certain varieties which possess some of the Early Rose attributes, but which difl:ered in color of bloom, and shape and color of tuber to such an extent that it has been decided to omit them entirely in the present classification. The comparative unimportance of the varieties, from a commercial standpoint, is also another con- sideration in leaving them out. In the description that follows, an attempt is made to cover the Early Rose proper, and to note such departures from it as may occur m varieties belonging to section 3. Description. — Section 1. Vines of medium height, with stout, rather erect, dark green stems and medium to large leaves. Flowers rather abundant, white. Tubers elongate- iiattened to spindle-shape flattened (Figs. 244 and 245, and Fl. II-D). Eyes numerous and well distributed, shallow to medium in depth, some- times protuberant (Fig. 244). Skin smooth and, except in the White Rose, of a rather deeper shade of flesh color than Early Ohio ; the seed end usually a deep pink. In some types of soil, and in some regions, the color of the skin is very much intensified. Flesh creamy-white, sometimes streaked with red or pink. Sprouts rather long, medium thick, the base not much enlarged and usually clearly tinted with rose-lilac; leaf scales and tips creamy-white or tinged with rose lilac (Plate 2-D). The following varieties have been classed in section 1 : Fig. 245. — A well-shaped Early Rose tuber, but it is not typical of the variety. Clark's No. 1. Early Durham. Earlj' Fortune. Early Maine. Early Rose. Early Sunrise. Extra Early Fillbasket. Extra Early Vermont. Houlton Rose. Late Rose. Northern Beautj\ Rochester Rose. Early Thoroughbred. Somer's Extra Early. Early Vermont. Thorburn. Early Walters. White Rose (Extra Early and Woodbury's). 452 DESCRIPTION OF COMMERCL\L VARIETIES Section 2. — Vines larger and more luxuriant than those of section 1. Flowers rather abundant, but not opening as freely as in section 1. Tubers broad-roundish flattened to oblong-flattened, with rather blunt ends in the case of the King. Eyes not so numerous as in section 1 ; medium^ shallow except in overgrown Fig. 246. — A good specimen of a spaulding No. 4 tuber grown at Hastings Florida. specimens. Skin slightly deeper colored than that of the Early Rose. Sprouts shorter and thicker and usually enlarged at the base; color of sprouts mauve; loaf scales and tips deep mauve or magenta. The varieties classed under section 2 are: King. Manistee (Early and Improved). Spaulding No 4. (Rose 41. Group 5. Early Ohio. — Tii many res])ects the members of the Early Oliio group are very similar to those of the Rose, but inas- GROUP rx EARLY OHIO 453 much as it is so well known, and is so extensively grown commer- cially, it seems desirable to retain the Early Ohio varieties in a distinct group, rather than to merge them with the Kose varieties. The Early Ohio varieties, with the ex(!eption of the Late Ohio, Flan. 247. AND 248.— A good specimen of Early Ohio as produced iu Mail shortened longitudinal axis and increased transverse diameter. Fig. 249. — An excellent specimen of Early Ohio from the Middle West. Note lengthened axis and decreased diameter. are somewhat earlier-maturing than those of the Rose, and are much less profuse bloomers. This is made all the more apparent by the failure of a large number of the flower buds to fully expand. In the potato-growing regions of the Middle West, it is still one of 454 DESCRIPTION OF COMMERCIAL VARIETIES GROUP 5. EARLY OHIO 455 the leading commercial varieties. This is particularly true in the Eed Eiver Valley of Minnesota and North Dakota, and in the Kaw Valley in Kansas; it applies equally as well to other less well- known localities. Description. — Vines quite similar to those of the Early Rose, though as a rule they are somewhat stockier, do not branch as FiQ. 251. — ^A large but well-shaped and true-to-type, Early Ohio from Montana. Natural size. freely, and mature a week to ten days earlier. Flowers are white, but not quite so large as in the preceding group; the anthers are also considerably lighter in color, being a lemon-yellow instead of 456 DESCRIPTION OF COMMERCIAL VARIETIES a bright orange-yellow. Tubers are ovoid to round-oblong or cjdindrical, with rounded seed and stem-ends in ^vell-grown speci- mens (Figs. 247 to 251, PL II-E). Eyes numerous, rather shal- low but strong, sometimes protuberant. Skin flesh or light pink, except in the case of the White Ohio, which has a creamy-white skin with pink eyes ; the seed end is usually a deeper shade of pink ; surface of the skin more or less numerously dotted with small. P^iG. 252. — A good specimen of Beauty of Hebron. raised, corky dots (lenticels) ; more conspicuous when grown in some soils than in others. Sprouts short, much enlarged at the base, color varying from carmine-violet to violet-lilac or magenta-lilac. The followinj? varieties have been placed in the Early Ohio group: Early Acme. Late Ohio. Early Market. Majestic (New Majestic) . Early Ohio. Prize Early Dakota. Early Six Weeks. Ratekin's Red River Special. White Ohio. Of the above list the Early Market, Majestic, Prize Early Dakota, and Ratekin's Red River Special are simply Early Ohio re-named. Group 6. Hebron. — Tlie varieties in the IIe1)ron group are chiefly distinguished from those of the Rose group by the color of their tubers. Most members of the group are early or mid- season varieties, the only exception noted being the Late Beauty of Hebron. Thirty-five years or more ago tlie group had some commercial importance, as botli the Early and the Late Beauty of Hebron were rather extensively grown. Their decadence has been largely due to the fact tliat ihey arc very susceptible to the GROUP G. HEBRON 457 late blight, and they have more or less degenerated or "run-out." Another and perhaps more important reason is that they have been superseded by better varieties. At the present time they are not grown commercially in any section, with the possible exception of certain localities where they are grown, to a limited extent, for the general seed trade. Description. — Varieties of this group may, with one exception, be classed as second early or mid-season. The Late Beauty of fM Fig. 253. — Reproducea from original cut of Burbank's Seedling. Note prominent eyes. Group 7, section 1. Hebron matures about the same time as the Green Mountain. Vines very similar to the Early Eose. Flowers white. Tubers elongated and distinctly flattened, sometimes spindle-shaped; ends more or less blunt (Fig. 252, PI. II-F). Eyes numerous, medium deep. Skin cream3'-white, more or less clouded with flesh color or light pink. Sprouts very similar to those in section 1 of the Early Eose group, but Mdth rather less color. The varieties classed in this group are as follows: Beauty of Hebron (Early B. of H.). Beauty of Hebron (Improved B. of H.). Beauty of Hebron (Late B. of H.). Columbus. Country Gentleman. Crown Jewel. Early Bovee. Gem of Aroostook. Harbinger. Junior Pride. Milwaukee. New Queen. Quick Crop. Star-of-the-East. Vigorosa. White Elephant. White Hebron. 458 DESCRIPTION OF COMMERCIAL VARIETIES % Group 7. Burbank.— In the early period of its introduction the Burbank potato or Burbank's Seedling, as it was then knovai, was rather extensively grown in the northeastern part of the United States ; but for the past quarter of a century, its popularity as a ■'v'-^ commercial variety has waned to such an extent that it is now rarely grown except for seed purposes. In the West, on the other hand, it is still quite popular in many sections. The russet type of the Burbank is a more recent acquisition, and is generally considered supe- rior to the original Burbank in table quality. The smooth skin or true Burbank type is grown rather extensively in the Stockton district in California, and in the western part of Oregon ; Avhile the russet types are produced in the Yakima Valley in Washington, and rather generally in Idaho and in certain parts of Nevada, Utah, Colorado and western Nebraska. The russet mem- bers of this group are assigned to section 2. Description. — Vines luishy and inedium large. Stems light to medium green, branched and spreading. Leaves abun- dant and medium in size, usually the major leaflets are rather long and narrow, tapering to a point which is generally curved, medium green in color. Flowers not very abundant, many falling off before opening; pedicel of flower cyme generally rather long and erect, and usually standing M'ell above the foliage ; calyx lobes rather long, usually extending well beyond the corolla before flower opens. There are no distinguishable differences in the vine Fig. 254. — Reproduced from original cut of the White Star variety. This variety was considered as a straight Burbank by several of the past generation of potato breeders. GROUP 7. burbank: 459 growth or floral characters of the smooth aiul russet-skinned types of the Burbank. Section 1. — Tuliers long, cylindrical to distinctly flattened in Fig. 255. — Three fairly good specimens of eastern grown Burbank tubers. Fig. 256. — Three good typical Wisconsin-grown, Russet Burbank tubers. Note moder- ate netting of skin. shape, inclined to be somewhat spindle-shaped; skin white to creamy- white, smooth or slightly netted (Figs. 253-255, PI. III-G). 460 DESCRIPTION OF COMMERCIAL VARIETIES Sprouts, base creamy-white, or faintly tinged with magenta; leaf scales and tips usually lightly tinged with magenta. Section 2. — Tubers have russet skin, heavily netted or reticu- lated (Figs. 25G and 257, PI. III-G'). In all other respects than color and netting of the skin, the tuber characters of the Russet Burbank are similar to those of Section 1. Fifi. 257. — Tuber "A" rcprosonts sents a broader, flatter shape which is typical in netting of most western-growi other western states. The varieties given below Section 1. Burbank or Biirl)ank's Late Puritan. Money Maker. ]'ri(lc of ]\Iultnomah. White Beauty. White Chief. m ideal-shaped Russet Burbank. Tuber "B" repre- not considered desirable for seed stock. Tubers are 1 stock such as may be tound in Colorado, Idaho and are considered members of this group : Seedling. Section 2. California Russet. Cambridge Russet. Golden Russet (Old's). Netted Gem. New Wonderful. Russet Burhank. Rusty Coat. Seabproof (Salzer's). GROUP 8. GREEN iMOUNTAIN 461 Group 8. Green Mountain. — The members of the Green Moun- tain group may be said to divide lionors with those of the Kural in their commercial importance as a late or main-crop variety. They seem to be peculiarly well adapted to northern latitudes, FiG.zoS. — -Three good specimens of Wisconsin-grown Green Mountain tubers. Fig. 259. — A good tj-pe specimen of Green Mountain. where the rainfall is al)undant and the temperature is not exces- sively high. As a rule they do not succeed as well in localities where they are subjected to unfavorable conditions of growth during the time they are forming tubers, as do the members of the Rural group. Recent observations indicate that most, if not all, of the 462 DESCRIPTION OF COMMERCIAL VARIETIES members of this group are peculiarly susceptible to mosaic infection of the foliage with a consequent material reduction in the yield of the tubers. They are also among the most susceptible to late blight infection of both vine and tuber. The varieties in this group are divided into two sections, accord- ing to whether they have white or slightly-colored sprouts. Descripiion. — Vines large, strong and well-branched. Stems light green in color, usually distinctly winged. Leaves large, leaf- FiG. 200. — Cross section of a Green Mountain tuber. Natural size. lets broad, smooth and more or less flaccid, medium green. Flowers abundant, white, fair size, rarely producing seed balls naturally, except under very favorable climatic conditions. Tubers moder- ately to distinctly oblong, usually broad-flattened with more or less blunt ends (Figs. 258-260, PL III-H) ; eyes medium in num- ber, rather shallow, -nath strong bud-eye cluster. Skin a dull creamy-white or light russet color when well netted. Sprouts in section 1 rather short and stubby, base, leaf scales and tips creamy- white, w^hile in section 2, with the exception of Twentieth Century, they are mostly without color at the base; the leaf scales and tips are usually faintly or distinctly tinged ^nth lilac or magenta. GROUP 9. THE RURAL 463 The following varieties have been classed in the white sprout division! Section 1. Bethel Beauty. Bishop's Pride. Blightless Wonder. Bugless (Gurney's Bugless). Clyde. Delaware. Farmer. Freeman. Gold Coin. Green Mountain. Green Mountain Jr. Green Mountain (Lowell's). Basting's (2). Keystone. Section 2. American Giant. Carman No. L Empire State. Late Blightless. Long Island Wonder. McGregor. McKinley Mill's Pride. New Oregon. Norcross. Pride. Silver King (2). Snow. Uncle Sam. Washington, t White Harvest (Gurney's). White Mountain. Longfellow. Rustproof. State of Maine. Group 9. — The Rural group includes a large number of strong- growing, late-maturing varieties. Collectively they are now com- FiG. 261. — Upper and lower view of a Rural New Yorker No. 2 tuber. monly referred to by ISTew York State growers as "blue-sprout" potatoes, in contradistinction from the "white-sprout" varieties belonging to the Green Mountain group. The members of the Eural group seem to be admirably adapted to southern and western t Classified by A. L. Dacy, Exp. Sta., Morgantown, W. Va. .464 DIOSCRIPTION OF COMMERCIAL VARIETIES New York, and to certain sections of Michigan, Wisconsin, Iowa, and Minnesota. The tubers keep Avell in storage and are slow to germinate in the Spring. The vines develop slowly at first, but, as tlie season advances, they branch rather freely and develop fairly Fig. 2()2. — Four tubers of Rural New Yorker No. 2, showiuc variation in position and depth of the terminal eyes or, as they are more generally known, the bud-eye cluster. large plants. Tuber formation seems also to be delayed, but when the right growing conditions prevail, in the latter part of the season, they grow very rapidly and, if the season of favorable growtli is prolonged, the larger tubers are quite apt to be hollow-hearted. As a group, the tubers are of desirable shape, attractive color, and GROUP 9. THE RURAL 465 fair taljle qualit}', uiid the vines are fairly resistant to drought and to diseases other than late hlight. As in the case of the Burbaid<; group, two sections have been created in order to include the Eusset Eurals, which, save for the color of the skin and a heavier netting, are practically identical in every other respect with those of the white-skinned varieties included in section 1, the one description answering for both. Description. — Vines medium large. Primary stem upright, usually long-jointed, and rather sparsely covered with foliage; Fig. 263. — Cross section of a Rural New Yorker No. 2 tuber. Natural size. lateral branches more or less decumbent, giving the plant a straggly appearance. Stems more or less distinctly streaked with dark purple. Leaves medium-sized to rather small, dark green, more or less rugose or crumpled and leathery or firm to the touch. Flowers medium to fairly abundant in some varieties and of fair size; the central portion of the corolla deep violet-purple with the color growing lighter toward the outer portion; five points of the corolla white or nearly so. Tubers broadly round-flattened to short-oblong, or distinctly oblong-flattened (Figs. 261-2G3, PI. IIT-I). Eyes few, very shallow, bud-eye cluster strong and usually 466 DESCRIPTION OF COMMERCIAL VARIETIES depressed. Skin creamy-white and occasionally netted in the varieties of section 1, while in those belonging to section 3, the skin is a deep russet color and much netted. Sprouts short, base enlarged, dull white; leaf scales and tips medium to deep violet- purple or pansy-violet. Section 1. The varieties classified under section 1 seem to be, in most cases at least, the result of a re-naming of old varieties. Arcadia. Ohio Wonder. Banner (Livingston's Banner). Pan American. Carman No. 3. Peerless (Bresee's No. 6) or Boston. § Dooley's. Potentate. Doolin, John. Prince Henry. Great Divide. Prosperity. Hart's No. 1. Rhind's Hybrid. Improved No. 5. Rural New Yorker No. 2. Isle of Jersey. Sensation. Jackson White. Sir Walter Raleigh. Late Beauty (Heath's L. B.). Snowflake Jr. | Late Surprise (Heath's med.-late). Todd's Wonder. Late Victor. Uncle Sam. || Lily White. White Giant. Manila. White Swan. Market Prize. % White Globe. Million Dollar. Nebraska. Non-Blight. Noxall. Section 2. Golden Harvest. Late Petoskey (Rural Russet). Golden Rule. Russet Rural (Dibble's Russet). Golden Rural. Group 10. — The Pearl group is one of the smallest and at the same time one of the least known, so far as its origin is concerned. It is chiefly grown in Wisconsin, Nebraska, Colorado, and Idaho. There are three distinct types in the group, the first of which is § Not the true Bresee's Peerless, though listed as such. X A. L. Dacy's Classification. II At the present time there seems to be two distinct varieties bearing the name of "Uncle Sam." One belongs to the Green Mountain and the other to the Rural Group. The original " LTncle Sam" is a member of the Green Mountain group GROUP 10. THE PEARL 467 represented by the Pearl, the second by People's and the third by Blue Victor, from which the Pearl probably owes its origin as a bud variation or sport. The members of this group, like those of the Triumph and Green. Mountain, are very susceptible to mosaic; and it is becoming increasingly difficult to produce or to purchase disease-free seed. Description. — Maturing about with Green Mountain. Vines medium to large, strong, healthy and as a rule Avell-branched ; stems dark green (in section 3 streaked with purple), more or less upright in early stages of gro^^h, but gradually assuming a some- what decumbent position as the plant approaches matu- rity. According to Fitch- the main stem of the Pearl should assume a more or less horizontal position, and the lateral branches an upright position. Leaves medium to large in size, rather fiat, somewhat rugose, and ap- proaching dark green when well grown. Flowers not abundant, and many of the buds that do form drop off either in the bud or just prior to opening; corolla is white with pale lemon-yellow stamens. When plants are normal, they do not, as a rule, produce many seed balls, to large in size and in favorable growing seasons often get large and of uneven shape. N'ormal tubers are round-flattened to heart- shaped flattened, usually heavily shouldered due to deep recession of stem (Figs. 264 and 265, and PI. I-C). Eyes rather shallow, sometimes protuberant, or in off -type specimens inclined to be deep with heavy eyebrows. The bud-eye cluster in a normal specimen is shallow, while in an abnormal one it is usually distinctly depressed. When freshly dug, the Pearl has a distinct pinkish or light purple tinge around the eyes, particularly at the seed end ; exposure to the light or prolonged storage seems to reduce the color to such an Fig. 264. — Four views of Pearl tubers. Tubers in section 1 are medium 468 DESCRIPTION OF COMMERCIAL VARIETIES extent that it is scarcely, if at all, visible. Skin a dull white, generally more or less netted. Sprouts have base, leaf scales and tips slightly or distinctly suffused Anth light lilac. Secfion 2. — The tubers of the People's potato, which is the sole member of tliis section, are so nearly identical in every respect, except in color of skin, as to make it unnecessary to do more than describe the color which, when well grown in the lava ash soils of southern Idaho, is a rich russet-brown. The russet color is not due as in the case of the Eusset Burbank, to a heavy, corky- Ijrown growth, but rather to a coloration of the skin it- self. It is the same kind of pigmentation as is found in some of the Russet Rural varieties, such as the Golden Rural. Section 5.— The Blue Victor is the sole member of this section and its tubers Fig. 205. — A very good type of the Pearl differ from the Pearl in that they are a deep blue color, frequently with creamy-white splashes around the eyes. The sprouts, base, leaf scales and tips are a vinous-mauve. The varieties belonging to the Pearl group are as follows: Section 1. Section 2. Section 3. Dearborn People's Blue Victor Pearl Rehoboth The Dearborn and IJehoboth arc considered identical Avith the Pearl. Group II. — The Peachblow group is an interesting one because it is the oldest of the twelve groups given. The "old- timer" or tlie potato grower of 50 years ago, usually harks back to the large yields and excellent table qualities of the Old Jersey Peachblow, and constantly regrets that it has been allowed to dis- appear. During the past half century or more a considerable number of Peachblow varieties have come and gone until, at the GROUP 11. THE PEACHBLOW 469 present time, there are practically but two members of this group that are now grown comjnercially in the United States. These varieties are the Improved Peachblow and the McCormick. The former is grown in a limited way in some sections in Colorado and the latter as a late crop throughout a large portion of the South, beginning with Maryland and extending to Georgia. This group is characterized by the extreme health and vigor of its vines. It includes some early varieties, but for the most part they are late to very late in maturing. The McCormick is i^, ^^, the most dependable "* ^^^ variety that we have to grow as a late crop in the South, as it is the only variety that will success- fully withstand t h e extreme heat, and occa- sionally extreme drought as well, and at the same time make a fair crop if rain and cool weather come early enough in the *'i£*''" Autumn to give the Tt(iOf^(i^aT^^ timp for ^i"- 206.— A fairly representative McCormick necessary time l O r ty^er. Note number and depth of eyes. tuber development. Description. — Vines strong, erect, healthy, vigorous and deep- rooted. Stems large, strong, woody, and medium green in color. Leaves medium in size and abundance, rather thick, rugose, or crumpled, medium to large in size and rather dark green. Flowers usually abundant, purple, and, in the case of the McCormick, inclined to set fruit rather freely when conditions are favorable. Section 1. — The tubers are roundish or ovoid, to round-oblong, somewhat flattened. Eyes numerous and usually quite deep (Fig. 266, PI. IV-J), invariably suffused with carmine or crimson, the intensity of which is more or less variable. Skin creamy-white to white splashed with crimson or magenta or flesh colored. Sprouts have base, leaf scales and tips of reddish-violet. Section 2. — The tubers are round-Jhitteiied to lieart-shape Hat- 470 DESCRIPTION OF COMMERCIAL VARIETIES teiied. Eyes few, mostly at seed end, very shallow except bud-eye cluster, which is generally more or less depressed (PI. IV-K). Skin a deep reddish-pink or magenta, carmine colored around the eyes. Sprouts similar to those in section 1. Section 1. Dvkeman. Early Peachblow (Hall's). Extra Early Peachblow. Jersey Peachblow. McCorniick (pink). McCormick ( white ) . Section 2. Improved or Perfect Peachblow ( Rand's ) , Synonym. Red McClure. New Improved Peachblow (Nichols'). New White Peachblow (Thorburn's). White Peachblow. Nott's Peachblow. Group 12. The Up-to-Date group of potatoes is of Euro- pean origin. The leading member of the group, Up-to-Date, was Fio. 267. — A good type tuber of the Up-to-Date variety. Note fewness of eyes and gen- eral smoothness of tuber. originated by Archibald Findlay of Scotland in the late eighties, and ranks among the leading late or main-crop potatoes of Great Britain. The Factor, introduced by Sutton and Sons of Eeading, England, is so nearly identical M'ith Up-to-Date as to be practically indistinguishable from it. Both of these varieties were introduced by the United States Department of Agriculture in the spring of 1905, and have been continuously grown in the Department's variety collection since that date. Within the past few years some GROUP 12. THE UP-TO-DATE 471 varieties have been offered by seedsmen under American names tliat are very similar to Up-to-Date. The members of this group do not appear to have a very wide range of adaptation in this country, but where they have been tested under good environmental con- ditions, they have made a very satisfactory crop. They are best adapted to rather heavy soils, and to a rather cool climate, such as may be found in the Northwest, where it proved extremely satis- factory at the Western Washington Station, Puyallup, Washington. Descriplion. — Vines medium to large. Stems quite large, and woody, decidedly angular, dark green. Leaves medium size, ratlier thick, and having a peculiar twisted appearance; dark green. Flowers rose-purple, moderate to rather profuse bloomers; pistil thick and usually twisted or curved ; stamens seldom if ever produc- ducing viable pollen. Tubers oblong-flattened to somewhat obovate- flattened, usually of a good size. Eyes few, very shallow, mostly at seed end (Fig. 267, PI. IV-L). Skin creamy-white, moderately netted or nearly smooth. The following varieties have been classed in the Up-to-Date group by Henshaw.^ Col. Staney. Gen. Roberts. Conquering Hero. Heather Blossom. Cottar. Highlander. Dalhousie Seedling. King Loth. Dalmeny Argon. Motor. Dalmeny Beauty. Nobleman. Dalmeny Helium. Scottish Monarch. Dalmeny Hero. Scottish Triumph. Dalmeny Regent. Sensation. Duchess of Buccleugh. Sir Mark Stewart. Duchess of Cornwall. Superlative. Dumfries Model. Table Talk. Enquirer. Talisman. Factor. Up-to-Date. Warrior. Only two of the foregoing varieties liave come under the writer's observation, viz., Factor and Up-to-Date. In addition to these, several varieties now listed by American seedsmen have been studied and assigned to this group. These are Bull Moose. Producer. Cumming's Pride. Pres. Roosevelt. Gold Standard. Solanum Sp. (from South America). Moreton. Verbots (from South America). Bull Moose is quite popular in southern Indiana and in the Louisville district in Kentucky. 472 DESCRIPTION OF COMMERCIAL VARIETIES QUESTIONS ON THE TEXT 1. What scheme of classification was first advocated? By whom? 2. Give the next suggested system of classification. By whom? 3. How did the third system difl"er from the second one? By whom submitted ? 4. Who was the first to devise a classification system in the United States? 5. On what was his grouping based? How many groups? Name them. How subdivided? 6. What changes did Kohler make in his later classification? 7. What variety classification did Ballou offer? 8. What variety classification did Milward present? 9. How does this classification compare with Kohler 's? 10. How many groups did Fitch make in 1914? Name them. 11. In what respects is this an improvement? 12. Give iSnell's classification. 13. Give author's (Stuart's) classification. 14. How does this differ from the preceding ones? How many groups? 15. Wliat other character has been suggested by Kranz for the identi- fication of the groups? 16. Of what value is the group system in studying varietal relationships? 17. Give the classification key offered in this chapter for each group. 18. What is said regarding group 12? 19. Give the chief characteristics of the Irish Cobbler group. 20. To what sections and climatic conditions is the Irish Coljbler best suited? Discuss it as an early truck crop. 21. What varieties or so-called varieties belong to this group? 22. Describe the Triumph group, and compare the members with those of the Irish Cobbler group. 23. Where is the Triumph most extensively grown? 24. What varieties or so-called varieties belong to this group? 25. Of what commercial importance is the Early Michigan group? Where chiefly grown? 26. Describe the Early Michigan group? Name the varieties. 27. How do the Aarieties belonging to the Early Rose compare in point of numbers to those of the other groups? 2S. Of what importance is this group commercially? 29. Describe the sections of the Early Rose group. ;!0. What varieties belong to each? 31. Is there any general similarity between the Early Rose group and the Early Ohio group? Give differences. ?>2. Where is the Early Ohio most extensively grown? Give varieties. 33. Describe the Early Ohio, giving characteristics of plant and tuber. 34. In what respect do the varieties of the Hebron group differ from those of the Early Rose? Describe the former. 35. To what is the decadence of this grouj) due? Give varieties. 36. Where is the Burbanlc group of potatoes commercially grown? 37. Name the sections of the group. Name varieties of each. I'S. Describe and compare the two sections. 39. What sections and conditions best suit the Green Mountain group? 40. To what diseases are its members peculiarly susceptible? Describe the group. REFERENCES CITED 473 41. Into how many sections is the group divided? Give basis of division. 42. What varieties belong to each section? 43. Describe the plant and tuber characters of the Rural group. 44. To what section of the country is it adapted? 45. Give the names of as many varieties as possible under section 1. 46. Name the varieties belonging to section 2. 47. For what is the Pearl group chiefly distinguished? Describe the group. 48. How many distinct tuber types are there in the group? 49. Distinguish between the sections. 50. Describe the People's potato. 51. Describe the Blue Victor. 52. Name the varieties belonging to the three sections. 53. How many real commercial varieties belong to the Peachlilow group at tlie present time? Name them by sections. 54. What member of this group is especially adapted to the production of a late crop of potatoes in the South? How so adapted? 55. Describe the Peachblow plant and the tubers in sections 1 and 2. 5ti. What varieties belong to sections 1 and 2? 57. What is the history of the Up-to-Date group? Give adaptation. 58. Describe the vine and tuber characteristics. 59. Name the varieties included in this group which are or have been offered to the trade by American seedsmen. QUESTIONS AND EXERCISES SUGGESTED BY THE TEXT 1. Make a rather complete list of the varieties of potatoes grown locally. 2. From dealers and growers obtain standard samples of each of these. Learn to know standard samples of leading varieties. 3. Determine from name, as well as from characteristics, to what group each belongs. 4. With these on exhibit plates, -write labels on cards for each and include group names and synonyms. Learn to know the groups better by this exercise. 5. Prepare an appropriate premium list to cover all the groups and varieties likely to be grown in your county or state. 6. Make a large drawing showing plans for a large booth on potatoes at a fair. 7. Make up a list of several questions for debate on potato topics. 8. On one of these questions, concerning varieties, outline the arguments on both sides of the debate. References Cited 1. Ballou, F. H. 1910. A practical classification or grouping of varieties of potatoes. Ohio 8ta. Bui. 218: 593-595, June, 1910. 2. Fitch, C. L. 1910. Productiveness and degeneracy of the Irish potato. Col. Hta. Bid. 176: 16, 1910. 2 (a). 1914. Identification of potato varieties. loica Agr. Exten. Dept. Bui. 20: 16-32, April, 1914. 3. Hexsiiaw, H. 1911. Experiments in potato growing. Jour. Bd. Agr. (London) 17: 892-904, 1911 (see p. 901). 4. KoHLER, A. H. 1909. Potato experiments and studies at University Farm. Minn. 8ta. Bui. 114: 311-319, 1909. 474 DESCRIPTION OF COMMERCIAL VARIETIES 4 (a). 1910. Potato experiments and studies at University Farm in 1909. Minn. Uta. Bui. 118: 65-141, 1910. 5. Kbanz, F. a. 1918. The position of the flower stalk as a help in potato identification. The Pot. Mag. 1: 13, Nov., 1918. G. Lenne. 1855. Abs. U. S. Patent Office Rpt. 1855: 210-217, 1855. Abs. Jour, filr Landwirthsschaft etc., 3rd Jahre, Erste Abtheilung: 250-252, 1855. 7. MiLWARD, J. G. 1912. Commercial varieties of potatoes for Wis- consin. Wis. Sta. Bid. 225: 7, 1912. 8. Putsch, C. W. E. and F. J. Vertuch. 1819. Versuch einer Mon- ographie der Kartoffeln, etc., Weimar 1819: 1-158, 13 pis., 8 figs, of foliage and blossoms, 33 figs, of colored tubers. 9. Snell, K. 1921. Kartoffelsorten Arbeiten zu einer allegemein und speziellen Sortenkunde. Arbeiten des Forschungsintitutes filr Kartoffelbau, etc.. Heft 5 p. 1-78, 10 figs., 2 col. pis., Berlin, 1921. 10. Stuart, W. 1915. Group classification and varietal descriptions of some American potatoes. U. /S'. Dept. Agr. Bui. 176: 1-56, March, 1915, (see p. 3-13). 11. ViLMORiN, C. P. H. L. 1882, 1886, 1902. Catalogue Methodique et Synonymique des Principales Varietes des Pommes de Terre. Paris, 1882. Ed. 2, corr. et aug. de plus de 200 varieties, 51 p., Paris, 1886. Ed. 3, refond. et aug. de plus de six cents varieties, 37 p., Paris, 1902. APPENDIX STUDENT'S PROJECT IN GROWING A FIELD OF POTATOES FOR PROFIT In the following outline it is assumed that this project begins with fall preparation of the field, and continues through the cycle until the potatoes are stored and marketed the following fall and winter. If desired, the project may begin in the spring instead. The operations would be in the same order, and this outline would serve the same purpose. The citations for study in the third column are to chapters in this volume. At the end of each chapter other references will be found. Citations to Chapters. Project operations. Select field. Study involved. Desirable soil ; warm or cold soil ; physical texture of soil; mois- ture; fertility; best crop to precede potatoes. Time of plowing: Advantages of fall plowing and conditions un- der which it may be inadvisable to do it. Compare varietal groups ; varietal suitability to soil and climate; disease resistance ; produc- tivity; market requirements. Value of good seed ; certified seed ; sources of good seed ; cheapness of good seed and costliness of poor seed. Why buy seed potatoes ? Need of early " purchase of seed ; best method of storing seed during late fall and winter months. Selection and purchase of Kind and amount of fertilizer Plowing. Selection of suitable va riety. Source of seed stock. Purchase of seed stock. commercial fertilizers. Home mixing of fertilizers. Make winter study of dis- eases and insects. to buy ; cooperative buying. Desirability of early purchase. Advantages of home mixing; methods ; cost. Local enemies of the potato; na- ture and prevention of diseases, methods of combating insects; sprays to use; spraying appa- ratus; field treatments to pre- vent diseases and insects. Ill, IV, V. IV. VII, XXI, XXII. VII. VII, XIII. V. V. XV, XVI, XVII. 475 476 APPENDIX Make plans for storage pits and storage houses. Make winter study of mar- kets. Preparation of land and application of fertilizer. Prepare seed. Planting seed. Early tillage. Tillage after germination. Combating enemies and con- trolling diseases. Construction of storage house. Field selection of seed pota- toes. Harvesting of crop. Marketing the crop. Principles of storage; drainage; temperature control; ventila- tion; light exclusion; mate- rials needed ; cost estimates per bushel capacity. Charting market prices in local and distant markets; compare prices for a series of years where possible; best time to market potatoes; relation to variety and season. Plowing under green manure; barnyard manure ; time of oper- ation ; benefits ; depth of plow- ing; costs after treatment; marking or laying otf rows; compare kinds of stable manure for potatoes; fresh or rotted. Treatment of seed potatoes ; quantity of seed to prepare per acre; greening; vitality; cut- ting; size of seed piece; hold- ing cut seed ; dusting cut seed. Time; methods; types of plant- ers ; distances ; depths ; ferti- lizing at planting time. Pre-germination tillage; benefits; implements; methods; number of times. Purposes; implements; frequen- cy; depths. Objects of spraying; materials; frequency of application ; spray outfits ; results. Review plans and lists of mate- rials made; dimensions needed; location; probable cost of ma- terial and labor; advisability of building, etc. Object of field selection. How and when to select In field. Improvement by selection. Hill- to-row plan of improvement; mass selection; strain test; storing seed potatoes. Time; relation to market de- mands; transportation; prices; methods of harvesting; meth- ods of picking; best containers; handling when harvested. Conditions of market; size and condition of crop both as a whole and locally; what por- tion to market at harvest time; XIII, XIV. XII. IV, V VII. VIII. VIII. XV. XVI. XVII. XIII. XIV XXI. XII. APPENDIX 477 storing crop, and advisa- bility of same. Soil sanitation. Cost accounting. Financial summary. grading and sorting to size; containers for marketing; haul- ing; cost of marketing. Methods of handling for storage; soundness of stock; danger of shrinkage; other risks; proba- ble benefits of storage. When is storage not profitable? Crop rotation; crops to use for rotation purposes ; connection between crop rotation and fun- gous and insect and animal pests; length of rotation; use of cover crops. Cost of man and horse labor in- volved in the production of the crop ; cost of seed potatoes ; cost of fertilizers (chemical, stable, and green manures) ; cost of fungicides and insecti- cides ; storage ; marketing ; rental of land; interest on money invested in crop; re- ceipts from crop. Keep close record of every item of ex- pense and income. Determine cost per bushel and per cent of profit. Study cost account- ing. Prepare financial analysis from cost accounting data. Write in narrative form a complete record of procedure and results. VII. XII, XIII. y, VI. XI. XI. DEMONSTRATIONAL AND INSTRUCTIONAL FEATURES IN POTATO PROJECTS 1. When fighting potato l)eetles, compare spraying methods with dusting. 2. Compare yields from different kinds and amounts of commercial fertilizers, farm manure or green manure. 3. Compare results from selected and unselected seed. 4. Compare yields from different lots of seed of same variety from different sources or growers. o. Plant rows respectively with one-eye, two-eye, many-eye pieces and whole tubers. Observe differences in number of stems and tubers per seed piece and of marketable tubers. 6. Test high ridging in comparison with almost level culture. 7. Compare results from untreated and treated seed. 8. Compare different varieties in regard to yields of marketable tubers. 478 APPENDIX POTATO EXHIBITS Objects of Exhibits. — Until recently, the primary object of a potato exhibit seems to have been to gather together as large a collection of varieties, or so-called varieties, as was possible in any given section. The premium list was usually a long one and little attention was apparently given to duplication of varieties under different names. Each exhibitor was allowed to arrange his exhibit of ])otatoes along with any other vegetables or fruit that he might be displaying, and thus it came about that potatoes were scattered here and there throughout the exhibition hall, with no regard to the convenience of the public or the judges who had to pass upon their relative merits. Fortunately, such a system of displaying exhi- bition material, and of offering premiums for a nondescript col- lection of varieties is rapidly passing away. The real object of holding an exhibition or show should be that of educating the public, by bringing together for their inspection and study, the most desirable varieties, properly named, and rep- resenting the best ty{)e specimens of the variety. The following suggestions are offered as an aid to such an accomplishment. The number or the quantity of tubers of each variety displayed should be uniform. If a plate exhibit is called for, the number of tubers should be specified; five or six tubers are sufficient. The peck display seems to have many adherents. Some potato associations, such as the Wisconsin Potato Growers' Association, provide wooden trays having just enough depth to permit of two layers of potatoes. All exhibits of a given variety should be assembled together, in order to permit of ease of study and comparison. No premiums should be offered on any but strictly commercial varieties, neither should a premium be offered on two varieties belonging to the same class or group, as for example Green Mountain and Gold Coin, or Rural New Yorker No. 2 and Carman No. 3. Selecting and Preparing Exhibition Tubers. — In order to intelligently select exhibition tubers, the exhibitor must have a clearly defined ideal in mind. He must know what the ideal tuber shape and skin color of the variety is and he must also know what size will be given preference by the judges. The Wisconsin Potato Growers /Association and many other State Associations now stipu- late or suggest a certain weight of tuber. For example, Triumph 7 ounces, Irish Cobbler 7 to 8 ounces, Green Mountain and Rurals APPENDIX 479 9 to 10 ounces, etc. This furnishes the grower a cue as to the best size to select. To secure tubers with an unbroken skin it is necessary to carefully hand-dig a large number of plants. The next step is to select a tuber having the ideal shape, appearance, and size and match it with others until a few more than the required number have been secured. Tubers intended for exhibit should be exposed to light as little as possible. As soon as selected they should be placed on a piece of paper or a sack, and allowed to dry oif for a few minutes, after which they should be wrapped in paper and stored away in a cool, dark room until desired for exhibition pur- poses. In preparing them for exhibit remove the wrapper and brush them free of adhering soil with a soft brush, being careful not to break the skin. All tubers showing discolorations or other imperfections should then be discarded, and the remainder again wrapped and carefully packed for shipment to the show. Attention to these details will always insure attractive show material. The Score Card as an Aid to Intelligent Judging of Exhi- bits. — The value of the score card in judging potato exhibits is now well recognized. Although a number of score cards are in use they do not vary to any material extent, they are all designed to serve as a basis for the correct interpretation of certain funda- mental qualities of the potato by assigning to them a definite number of points, the sum total of which is 100. Score Card. — The following score card is suggested as a guide and aid in judging potato exhibits : I. Varietal purity. — ( Free from mixture ) 20 points II. Conformity to type. — 1. Shape: correct for variety and uniform 20 points 2. Size: desirable for variety and uniform 10 points .3. Color : correct for variety and uniform 5 points 4. Surface: skin and eye characters normal for variety.... 5 points III. Condition and quality. — 1. Clearness, brightness, freedom from mechanical injury.. 15 points 2. Qiiality of flesh, clear and firm, not spongy, free from streaks, discoloration and hollowness 10 points .S. Freedom from disease, scab, rhizoctonia, roots 15 points Total 100 points Suggested Descriptive Terms to be Used in Describing Potato Varieties. — The following descriptive data were prepared and presented at the Fourth Annual Meeting of the Potato Asso- 480 APPENDIX ciation of America, by the Association coimnittoe on varietal nomenclature and testing of the })otato, in order to provide its members with a deiinite outline to be used as a guide in the descrip- tion of varieties. (A complete report of this committee may be found in the Proceedings of the Fourth Annual Meeting of the Potato Association : 93-94, Nov. 9-10, 1917. Wm. Stuart, Chair- man, A. L. Dacy, E. V. Hardenburg, C. L. Filch, R. Wellington, P. M. Lombard.) In the use of such a descriptive sheet it is intended that ail term^ not applying to the particular variety under observation shall be crossed. For example, if the plant is large, cross out small and medium ; or, if the tuber is oblong-flattened-rounded cross out all others on shape, or else place a check-mark opposite oblong- flattened-rounded. Suggested Descriptive Terms to be Used in Describing Potato Varieties VRACTERS. Seasonal conditions; favorable, unfavorable. Rainfall; scanty, normal, exces- sive. Temperature at blossoming period ; low, normal, high. Date of maturity. Date harvested. Yield. — ^Marketable tubers, .... lbs. Cull tubers, lbs. Desirability of variety for sec- tion; for home use....; for market Keeping quality of the variety ; poor, medium, good. Shipping quality of the variety; poor, medium, good. Eating quality of the variety; poor, medium, good. Resistance to late blight; none, little, much. Resistance to common scab; none, little, much. Resistance to other diseases; none, little much. Observer. PLANT en Size. — Small, medium, large. Habit. — Upright, medium, spreading. Stems. — Slender, medium, stout; little or much branched; slightly or distinctly angular; winged or smooth ; wings wavy or straight ; color light or dark green; much or little tinged with violet. Leaves. — Sparse, abundant; small, medium, large. Leaflets. — Narrow, medium, liroad ; smooth, hairy; light, medium or dark green. Floicers. — None, few, medium, many; buds persistent or dropping be- fore opening; corolla white, rose- purple, violet, lavender or blue. Season of Maturity. — Very early, early, medium, late, very late. General Information. — Source of seed. Date secured. Amount planted. Size of seed, whole, cut, eyes, ozs. Place. — Date planted, year, .... Distance between rows, , plants, Area in square feet. Soil type. APPENDIX 481 TUBEB CHARACTERS. ;5'i;^e._yniall, medium, large; uni- Eyes.— Few, medium, many; uni- form, not uniform. formly distributed or mostly at apical (bud end; eyes shallow, medium, deep; eye- /S/tape.— Oblong— flattened— rounded. brows short, medium, long; Elleptical— flattened— rounded. curved or straight, curve simple Oval — flattened — rounded. or compound. Roundish — flattened. Cubical — flattened. Apical end rounded, blunt. Sprouts. — Few, medium, many; slen- Basal end rounded, blunt, de- der, medium, stout; tips and pressed, notched and shouldered. jgaf scales are creamy-white, pink, magenta, purple, violet- ^ , , .,, . ^ ,, ... blue, or bluish-black; internodes Color of J'^/.u».— Glossy, dull, bluish-black, smooth; uniformly netted; flaked. Lenticels. — Few, medium, many; prominent, inconspicuous Cooking Test. — When the cooking and table qualities of differ- ent samples of potatoes are to be tested, it is extremely important that each lot of tubers should be baked or l)oiled under as nearly identical conditions as possible. The following method has been found to provide a uniform cooking test. Select three or four tubers of as nearly uniform size and shape as possible; boil each lot of tubers in separate saucepans or pots of the same shape and size ; begin the test at the same time and boil them alike until done. In the baking tests select the tubers in the same manner, but place each lot in the same oven. Maintain the oven temperature as nearly as may be at 380 degrees F. until they are done. On re- moval from the oven, break or puncture the skin so as to allow the steam to escape. Remove the skin from all but one baked or boiled potato as quickly as possible after removal from pot or oven, and mash the flesh with a fork or potato masher to determine the fineness or grain of the flesh, its color and general appearance, and its pleasantness of taste, as determined by actual test of its eating qualities. This test should be made without the addition 31 482 APPENDIX of butter or seasoning of any sort, in order to catch the true edible qualities of the tubers studied. Each remaining tuber should be set aside and allowed to get cold, after Avhich it is to be re-warmed for the })urpose of ascertaining to what degree the flesh retains its color and mealiness. The flesh of some varieties turns undesira- bly dark when re-warmed. Points to be considered in judging the table qualities of pota- toes are ease and uniformity of cooking; skin and flesh intact or nearly so when boiled ; texture of flesh ; character of grain when mashed; color of flesh; flavor. The following ratings have been found fairly satisfactory : Ease of cooking 5 points Uniformity of cooking 10 points Skin and flesh intact when boiled * 10 points Texture of flesh 15 points Grain when mashed 15 points Whiteness of mashed flesh 15 points Flavor .30 points Total 100 points POTATO TRIPS Trips to potato fields and elsewhere may be planned with profit. Students should be given 'an outline of the main features to be studied on each trip. They should prepare for the trip by reviewing these points. Notes should be made during the trip from which to write an accomit of the observations and lessons learned. 1. Visit fields for practice in choosing good potato soils. 2. Go to seed storage places and retail seed stores to study varie- ties, methods of handling, and protection and prices. 3. When large growers or others are preparing the soil for pota- toes, visit the fields and take notes on methods. 4. Such ]ilaces should also be visited when seed potatoes are being treated for scab and rhizoctonia, cut for planting, green- ing, etc. 5. Study planting machines of several kinds; if possible, when in actual operation in fields. 6. Study pre-germination tillage and after-tillage in potato fields. * jVo^e. — Waste, through rupturing of skin and sloughing away of flesh, may be entirely avoided by the use of a steam cooker. APPENDIX 483 7. Where Bordeaux mixture and other spray materials are being made for field work, make studies of methods and results. Study methods of spraying and dusting. If there are out- breaks of blight or other troubles examine them carefully. 8. At harvest time, study methods of harvesting, picking, hand- ling, sizing, grading and record keeping. 9. Take trips to study store houses under construction or when in use. Draw their plans and make estimates of cost for material and labor. Visit cold-storage plants if possible. 10, Study operations at shipping points; grading, classifying, va- rieties, summer cars, winter cars, cooperative endeavors, record keeping, crediting. 11. If any kind of manufacturing plant using potatoes is near visit that and study methods, products and by-products. 13. Visit large retail and wholesale markets. Study good and bad handling, diseases, containers, grades, sizes, varieties, prices. Secure specimens and compare in knife tests: smooth to pare thin, flesh white or true to type, sound and rather dry, not hollow, cortical layer thick, central areas small, not watery. APPENDIX 485 w w w w» w wKwa www ^g^'?^ a an ^ 33 2= ; 1 ■ 3 a : S3 5F c^ 3 5g ^ C n> m m I 3 3 3 ' o o o J»p 3 3 33 i^g S- 3S-S-S- ^Kl ^ ^ ^ ^ ^ ^ ^'^ o 3-2 3-5,^2. =^o >^ X r s-i^ cc w S- 5 ^ ^ Group number Date of intro- duction Vines:— strong or medium Form of tuber ♦Surface of tuber Eyes: — deep, shallow rr^^-^i- Color of skin ^ ^ f. ^ SJ„Z2;5^- 't^'? 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S S x5 O H3 «^ — T, x o ng of of Main sior X w, 1871 'S'" ^ ^'c- 2l2l2l1:i "So' « O _bj) » 3 wS a ° - § S S 2; o ^ ^ ,5' ^ — ^ ^ OS 09 C9 i;^ H H H » 5 5 - w w wa w w w afa^, faES fab O O 488 APPENDIX g S2 ss s" -o '^ * ■: ^ s 5 •^s ^ 5 i i -. -' S S^' - S i 1 ^ i 1" 5" ^ ^ > « S ■55:^ :ls 1 .1 1 igs o=l 3^ 1 1 s o„' "O o o aj „--~ „ 0) 1. fc, S_^.2 qs9u JO Jojoo UI5JS JO A\0][BqS JO claap ^ ^^ J3 X J3 J3 IIJOOIUS JO ii3noj — :3.iBjjng raqn:» jo lUJO^ I ujnipaiu JO 3UOJ}S uoi^onp -OJ^Ul JO n^BQ CS CO TC (N IN ^•■x c -7- 0-- --; www .S.S ^^ WW jaquinf.^ dnojQ OO KK aa ffi « • c3 a :w g .s.so wo s 2? -s^O aS : C'E E o ■fiOfe-S g .2P APPENDIX 489 ^ * ;? 00 3 Ph O 00 '^ PH ^ '^ a 1 ^ "2 ■« 1 °a d.'n 38 u ^SS S aoo — dS «> 'S :^fa ',? O o -- W =3 J3 " S3 o dH=" '^S^d^o^o^ feSJ-gd^gjM^dWdgS^u w'^K^ ° ►^ pi ^ hj> o d-^ a S H^ o 6 2 ^ ^ *-• ■n *a la "o "s -"' ^ ^ i ^^^ ^ i=3 dSod-, EgW o "S 2P S « '-'^ § S "r^ I I (S -: ^ fi 3 J f. a a lU ■^ ■^ m j; J, . "- > ?, a . M ■§ "c i V -s '-^ ^ :^^>-s J2 ■§3 7: '^ c ii^Hi -"-i « ai to T. tu V „• - „• _• ~ a) " s OP cu ~ a; ~ S a a a ro ^ ,^ g g '" '^ '^ "^ '" "-• ^ P3 1 a ph a (U 03 cc a w w is §,■§ «" [9 s e = it: PLidi (S (S fl! (S tl g ^ PL, PL, (1, fL, fl, 490 APPENDIX CJ s 3 u o 1 i 1 1 cc s; i 1 a 1 ^1 u to 'o a S c3 y^ 6 6 1 3 3 a 1 p. "d d^o & g d^d|d-^d| ii32 = c .1 11^ fM ^ fe X 1^ ^' h^ fe K w < d^ P5 d 2 "^ d w Hsag JO JOIOQ if &■ !S fi ■s- j: i£ St ■s ft'-: U15(S JO ioioo !S js & O OS o ^ ^ - . & si ^ d AVOnt!l(S JO daap J3 -a "m ■a ■s -s -s ■^n -J- "m J3 "»■» E-o _:s8/Ca q^ootus JO qsnoj aoBjins* fi £ c h f- " jaqm JO ^ J £ i. ^m 2n ^ ■gf UIJOj^ ^■^ <» X Ox ;; c ^ - b o o uintpaiu JO Saoj^s ■K fci m "S ■s S -S "S m ■Jr m ■Sfc: ■S^ — :sau!A dj ^ ^ „■ nosBag '^ a; £ £ -^ S " - e E e£ as noi^anp O) i2 "^ cc O 1^ •n -OJ^UI S !y! i^. § 58 ^r » )^ '.J § JO ai^ci '-' 1 W 1 1 ° 1 (N U 6 S. 2; jj s « « m a a ^ ^ -l ? °5 .t ^ a £ O fi 1 £ ^ c ■o i(£ "2 an ^ tf ^ 2 y ^^ p: >^ « fe ^>, >. bs Xo « ^i 'V -7 tic fc S n 3 1 eg ^ c^ :g- ^ ^ rr fc Q jaqiunjj dnojQ o ■gff 5? §5 1 c ■5 > 1 • c t:' S nr c '■i 1^ p. L p. (L p- 00-6 S 6 JO 6 O o i 6 s^ Landreth & S 1884, p. 55 N.Y. vol. 42: 71 W. P. Jerrard & 1903, p. 2 M. Thorburn & 1886. p. 32 K. Bliss & Sons' p. 13 ter Henderson & 1896. p. 12 ck's Garden & 1903, p. 7 M. Thorburn & 1881, p. 30 urney Seed & Nu Cat. 1912, p. 65 Philipp's Seed 1900 ck's Floral Guid 31 few Q tfO ^ ca (^ j> ^ o a > fem i ^ s EC it 's i ct i fe V & ^ S i a & i dl^^ & ^ M 4 •s s "§ E E S ■s-s i i i u -• jt^ i ^ J3 o ■§ ■§ §' -4 ° ^ ■i i s i .J ■s 1^ ^ ■s i^i 1^ a 6 s QJ E je ; yield and price per bushel by Provinces for the years 1912-191S inclusive. Province Year Acreage Total yield bu. Av. bu. per acre Av. price per bu. Prince Edward Island 1912 1913 1914 1915 1916 1917 1918 33,000 32,000 32,000 31,000 31,000 35,000 31,543 6,741,000 6,219,000 6,806,000 3,558,000 6,386,000 6,125,000 5,362,300 206.4 194.3 212.7 114.8 206.0 175.0 170.0 $0.26 .28 .23 .46 .52 .75 .63 1912 1913 1914 1915 1916 1917 1918 32,000 32,000 32,.500 34,000 34,000 41,000 51,250 9,447,000 5,369,000 7,165,000 4,759,000 6,935,000 7,173,000 9,942,500 298.6 167.8 220.5 141.2 201.0 175.0 194.0 .47 .52 .49 .58 .69 .92 .93 New Brunswick 1912 1913 1914 1915 1916 1917 1918 43,000 43,500 43,900 40,000 39,000 46,000 57,272 7,558,000 10,629,000 10,.534,000 5,772,000 7,488,000 6,891,000 9,077,600 174.6 244.4 239.9 144.3 192.C 149.8 1.58.5 .42 .44 .40 .64 .84 1.13 1.00 Quebec. . . . 1912 1913 1914 1915 1916 1917 1918 116,000 116,000 115,000 117,000 112,000 226,917 264,871 15,945,000 20,504,000 21,811,000 17,510,000 14,672,000 18,158,000 38,936,000 137.1 176.8 189.7 149.7 131.0 80.0 147.0 .35 .46 .42 .55 .97 1.38 .98 Ontario . . ... 1912 1913 1914 1915 1916 1917 1918 158,000 152,000 154,000 155,000 133,000 142,000 166,203 22,690,000 18,105,000 25,772,000 14,362,000 8,113,000 18,981,000 20,443,000 143.9 119.1 167.4 92.7 61.0 133.8 123.0 .59 .65 .47 .76 1.28 1.00 1.26 Manitoba . . . 1912 1913 1914 1915 1916 1917 1918 27,000 26,000 26,900 28,000 32,000 34,400 45,000 6,182,000 5,120,000 3,172,000 3,104,000 4,709,000 3,643,000 8,325,000 231.6 196.9 117.9 109.7 170.0 106.0 185.0 .35 .36 .72 .54 .61 .76 .56 APPENDIX 501 Province Year Acreage Total yield bu. Av. bu. per acre Av. price per bu. Saskatchewan 1912 1913 1914 1915 1916 1917 1918 31,000 31,000 30,600 30,300 47,000 67,700 59,793 6,552,000 5,138,000 4,085,000 4,428,000 7,319,000 9,010,000 6,950,900 209.7 165.7 133.5 146.2 176.0 133.0 116.3 $ .40 .47 1.05 .49 .62 .85 .96 Alberta 1912 1913 1914 1915 1916 1917 1918 27,000 26,000 26,300 27,300 29,000 48,917 44,247 5,775,000 4,350,000 3,652,000 5,155,000 4,783,000 7,409,000 3,119,400 211.6 167.3 138.9 188.8 177.0 151.5 70.5 .39 .39' .65 .33 .53 .76 1.11 British Cohimbia 1912 1913 1914 1915 1916 1917 1918 17,000 15,000 14,700 16,000 15,000 15,024 15,013 3,995,000 3,110,000 2,675,000 3,956,000 2,892,000 2,502,000 3,423,000 233.2 207.3 182.0 247.3 189.0 166.5 228.0 .49 .66 .78 .45 .70 .69 .97 ^'Zl? INDEX Absorbents to use on freshly cut seed, 60 Abundance and viability of pollen, 395 Acre yields by states and provinces, ' 495-501 Actinomyces scabies (common scab) , 264 Advantages of one- and two-man planter, 66 Advantages of pitting potatoes, 225 Ai'ration of storage house, 210 Affinity and non-affinity of pollen and ovules, 406 Air circulation in the storage house, 211 Air conduits in the storage house, 212 Alabama potato production. 111 Alberta Province, yearly potato pro- duction, 501 Alcohol production, 358 Alexander, 0. H., potato breeding work, 388 Alfalfa analyses, 29 Alfalfa in 4-year rotation, 42 Alfalfa sod, 24 Altitude effects, 15 American potato breeders, 385 American potato mania, 393 Ammonia system of refrigeration, 236 Amount of commercial fertilizer to apply, 32 Amount of plant food needed, 28 Amount of seed to use, 62 Ample storage facilities desirable, 203 Anatomical structure of potato tuber, 367 Anderson's method of selection, 415 Animal parasites, 291 Annual crop after potatoes, 40 App's cost data, 160 Appendix, 475 Appleman, C. 0., low temperature changes, 209 Application of Bordeaux mixture, 330 Application of commercial ferti- lizers, 33 Application of irrigation water, 84 Arizona potato production, 150 Arkansas potato production, 115 Aroostook Co., Me., production, 123 Aroostook Co., Me., type of storage house, 234 Arsenate of lead, how made and used, 337 , Arsenical injury, 284 Arsenite of zinc, 338 Arsenoids, white, pink, and green, 338 Arthur, J. C, formalin treatment of tuber, 333 Arthur, J. C, moisture requirements of plants, 20 Arthur, J. C, morphology of the tuber, 365 Artificial cross-pollination, 399 Artificially refrigerated storage houses, 236 Authorities differ on origin of the potato, 378 Average acre production of six lead- ing states, 121 Average acre yield by states, 8, 9 Average annual production in the South, 92 Average production by states, 7-9 Average production of three geo- graphical sections, 92 Bacterial diseases, 248 Bacterial wilt, 274 Bad and good Bordeaux mixtures, 326 Bad handling of seed, 69 Bagging potato flowers, 400 Bailey, L. H., early potato culture in America, 381 Baker, J. G., classification of tuber- bearing Solanums, 364 Ball, E. D., potato leafhopper, 315 Ballou, production centres in Ohio, Ballou's classification system, 438 135 503 504 INDEX Bauhin's description of the potato, 372 Beaufort, S. C, cultural practices, 83 Beecher, H. W., comment on Good- rich's work, 386 Benefits from germinating tubers before planting, 53 Berthault, P., tuber variations, 420 Berthon, H., potato tuber moth, 304 Best storage temperature, 208 Bird, R. M., Preparation of dry Bor- deaux mixture, 331 Bird and Grimes, suitable cars and proper loading, 197 Bitter, G., classiiication of tuber- bearing Solanums, 364 Blackfoot and Twin Falls, Idaho, districts, 149 Black-leaf, 40, 339 Blackleg, 271 Black scurf (Pvhizoctonia), 262 Blister beetles, 298 Blossoming of potatoes in Maine, 125 Bolley, H. L., soil sanitation, 38 Bordeaux mixture, 324 Bordeaux paste, 331 Bordeaux powder, 331 Botany of the potato, 364 Bovee's potato contributions, 390 Breeding and selection defined, 384 Bresee's potato-breeding work, 386 Briggs and Shantz, moisture require- ments, 20 Brine system of refrigeration, 237 British Columbia's yearly produc- tion, 501 British potato breeders, 392 Brittain, W. N., potato stalk borer, 299 Britton, W. E., Colorado beetle, 291 cutworms, 301 four-lined leaf-bug, 314 kerosene emulsion, 340 Brownell's potato-breeding work, 388 Bug-death, 332 Burbank group, 458 Burbank seedling, 458 Burbank's potato-breeding work, 388 Burlap sack, seed potato container, 193 Burley, Idaho, potato district, 149 liushel cost of storage, 239 Business principles, 156 Butler's conclusions on aiiration, 212 Butler's studies on relation of stor- age temperatures to loss in tuber weight, 218 Byar's, L. P., eelworm, 319 Calcium arsenate, 337 Caldwell, Idaho potato district, 149 California commercial production centres, 152 California crop, harvesting of, 152 California "tule" land district, 152 Canada's potato acreage and yields, 11, 12 Canada's production by provinces, 11, 500 Carbon bisulfid, 309 Careful harvesting of croj), 171 Caribou loam soil, 123 Carman's potato-breeding work, 389 Carpenter, C. W., fusaria sp., 257 Carriere's observations on variation, 416 Causes of poor stands, 69 Certified seed potatoes, 49 Character of mosaic disease, 278 Character of storage house, 225 Chemical elements in plants, 27 Chute method of filling storage house, 233 Cieca's observations on the potato, 369 Clark's potato-breeding Avork, 392 Classification and description of varieties, 435 Classification key (Stuart's), 440 Classification of flowering habits of varieties, 394 Classification of insect and animal pests, 290 Classification of tuber-l)earing sola- nums, 364 Climatic conditions in Aroostook Co., Me., 124 Clover analysis, 29 Clover sods, 25 Clusius, C. description of S. tubero- sum, 371 Color of stamens of flowers, 397 Colorado commercial potato dis- tricts, 143 Colorado construction costs, 239 Colorado potato beetle, 291 Commercial fertilizer formulae, 32 Commercial fertilizers and their use, 31 INDEX 505 Commercial production centres in South, 96 Commercially prepared Bordeaux powder, 331 Common scab, 264 Comparison of one- and two-man planter, 66 Comparison of second crop practices, 105 Comparison of WoUny's and De- naifife's data, 217 Conclusions on storage temperature, 209 Constituents of the potato, 348 Construction of Aroostook Co., Me., type of storage house, 234 Construction of dugout storage house, 226 Construction of insulated wooden storage house, 233 Consumption of potato crop, 360 Containers for potatoes and their cost, 102 Continuous cropping with potatoes, 41 Control measures for fusarium wilt, 256 Control measures for late blight, 254 Control measures for white grubs, 303 Cooking test, 4S1 Coon, G. H., early blight, 250 Cooper, M., brine system of refriger- ation, 237 Cooper, M., humidity of air in stor- age house, 210 Cooper, M., storage temperature, 208 Cooperative marketing organiza- tions, 199 Corbett, L. C, temperature of stor- age house, 208 Corrosive sublimate treatment, 332 Cost factors in potato production, 156 Cost of picking potatoes, 176 Cost of storage per bushel, 239 Cost per acre, 155 Cost per bushel, 155 Condon and Bussard's division of tuber, 367 Coy, E. L., potato-breeding work, 389 Craine, Thos., potato-breeding work, 390 Critical period in the potato plant's growth, 16 Crop rotation, 38 Cultural care of the growing crop, 74 Cultural practices in Long Island and New Jersey, 130 Cultural practices in Michigan, Wis- consin and Minnesota, 138 Cultural practices in N. D., S. D., Neb., and Kan., 140 Cultural practices in second crop production, 103 Cultural practices in Western New York and Pa., 131 Curly dwarf, 283 Cutting the seed, 58 Dacv, A. L., potato culture in W. Va., 117 Danger of cross-pollination, 401 Date of harvesting the potato crop, 166 Date of planting in Arizona, 150 Date of planting in Nevada, 150 Date of planting in Western New York, 131 Date of planting the three crops in the South, 99 Dean, Daniel, frequent sprayings, 343 Definition of potato grade terms, 180 Definition of term late or main crop potatoes in South, 100 Definition of tillage, 75 Dehydrated potatoes, 354 Demonstrational and instructional potato projects, 477 DenaifTe on humidity, 217 Denaiffe's storage loss studies, 216 Department Agriculture construc- tion costs, 242 Depreciation in value of instru- ments, 157 Description of S. tuberosum by Clunius, 371 Descriptive list of varieties, 485 Descriptive terms that may be em- ployed in describing varieties, 479 Desirabilitv of ample storage space, 203* Desirabilitv of securing a good stand, 69 506 INDEX Desirability of storing clean tubers, 213' Development of a market for fancy grades, 187 Development of potato culture in America, 381 Development of potato culture in France, 380 Development of potato culture in Great Britain, 379 Development of potato culture in India, 381 Development of potato culture in Prussia, 379 Development of potato culture in Sweden, 380 Dextrine, method of manufacture, 357 Difficulties involved in potato breed- ing, 394 Disadvantages of one- and two-man planters, 66 Disadvantages of pitting potatoes, 225 Disease classification, 247 Disease losses in storage, 212 Disinfection of storage house, 212 Distance between rows and plants in row, 61 Distribution of common scab, 265 Distribution of leaf roll, 279 Distribution of potato crop, 360 Domestic production of dehydrated potatoes, 356 Domestic production of dextrine, 357 Domestic production of potato flour, 354 Domestic production of starch, 349 Double-headed barrel containers, 193 Drainage in relation to pitting, 221 Draining the "tule" lands in Calif., 88 Dry Bordeaux, 331 Dugout or cellar type of storage, 226 Dust spray equipment, 345 Dusting freshly cut seed, 60 Early attention to selection, 415 Early blight, 249 Early history of late blight, 252 Early history of potatoes, 369 Early marketing of southern crop, 100 Early Ohio group, 452 Early or truck crop, 95 Early potato culture in England, 379 Early record of potato culture in the U. S., 381 East, E. M., high- and low-yielding hills, 419 East, E. M., potato-breeding tech- nic, 394, 401 East's classification of flowering habits of varieties, 394 Eastern Shore of Virginia Produce Exchange, 200 Economic importance of black scurf, 262 Eel worm disease, 318 Effect of bad handling of seed, 6!) Eff'ect of heat, 15 Effect of hot sun on tubers, 174 Effect of late irrigation, 86 p]ffect of leaf roll upon yield, 279 Effect of light on seed, 212 Effect of light upon edibility, 211 Eff'ect of mosaic on yield, 278 Effect of soil on quality, 14 Effect of too much moisture and soil on tubers when stored, 213 Efficiency of one- and two-man planters, 66 I'^lements necessary to supply po- tato plant, 27 Elevation of land in relation to pro- duction, 15 Elevator diggers, 170 Emasculation of flowers, 400 Entrance way to storage house, 231 Environmental influence on potato plant, 14 European potato mania, 393 Eustace, H. J., productive vs. un- productive plants, 418 Exhibiting potatoes, 478 Extent and importance of Southern crop, 92 Extent of Aroostook Co., Me., potato crop, 123 Extent of crop in Mich., Wis., and Minn., 136 Extent of Florida potato crop, 107 Factors determining character of storage house, 226 Factors governing size of storage pile, 213 INDEX 507 Fall crop potatoes in the South, 101 Fancy grades, 188 Farm manures, 30 Far-Western states, 141 Fayville and Parrot, potato stalk weevil, 300 Fenn's potato-breeding work, 391 Fertilizers, 31, 33 Field culture of seedlings, 411 Filling the storage house by chutes, 233 Findlay's potato-breeding work, 392 Fischer's selection work, 417 Fischer's starch variation in tubers, 417 Fitch, C. L., relation of soil tem- perature and moisture, 19 Fitch's classification of varieties, 439 Fitch's construction costs, 240 Flea beetle, 293 Flea beetle trap, 295 Florida potato crop, 107 Flowering habit of the potato, 394 Fluctuation in potato production in the South, 95 Fluctuation in production and causes, 7 Food requirements of the potato crop, 27 Foreign and American storage losses, 214 Foreign production of dehydrated potatoes, 356 Foreign production of potato starch, 350 Foreign vs. home production, 2 Formalin treatment, 333 Forms of dry rot, 257 Four-lined leaf -bug, 314 Fox's cost data, 160 Fraser, S., ventilation and tempera- ture, 208 French potato-breeding work, 392 Frequent sprayings, 343 Gasoline engine-operated diggers, 173 Gasoline engine operated sprayers, 345 Gathering the seedballs, 409 General practices regarding size of seed piece, 57 Georgia as a potato producer, 108 German potato-breeding work, 392 German potato production, 2 Germinating tubers in trays, 52 Germination losses, 218 Gleason and Heffron's potato-breed- ing work, 388 Glucose production, 357 Goff, E. S., high- and low-yielding plants, 417 Good stands desirable, 69 Good tillage, 75 Goodrich's potato-breeding work, 385 Grabbling potatoes, 169 Grading for a fancy trade, 187 Grading in the field, 189 Graf, J. E., potato tuber moth, 305 Graf, J. E., tuber-eating insect con- trol, 341 Graph of potato production in the South, 94 Graph of world's production, 2 Greeley, Colorado district, 143 Green manuring, 28 Green Mountain group, 461 Green, S. N., use of commercial fer- tilizers, 135 Greening and sprouting seed tubers, 51 Greig, R. B., the sprouting of seed potatoes, 53 Grimes, A. M., handling and loading Southern potatoes, 197 Group 1, Irish Cobbler, 443 Group 2, Triumph, 445 Group 3, Early Michigan, 448 Group 4, Rose, 450 Group 5, Early Ohio, 452 Group 6, Hebron, 456 Group 7, Burbank, 458 Group 8, Green Mountain, 461 Group 9, Rural, 463 Group 10, Pearl, 466 Group 11, Peachblow, 468 Group 12, Up-to-Date, 470 Growers' coiiperative marketing or- ganizations, 199 Grower's estimate of storage losses, 218 Grubb and Guilford, storage tem- perature, 208 Giissow, H. T., powdery scab, 280 Giissow, H. T., wart disease, 269 Hallet's method of selection, 416 Hand-harvesting implements, 167 Hand-hoeing, 81 Hand-operated sprayers, 344 508 INDEX Handlinfj potatoes, 195 Hardenburg, E. V., size of seed piece, 55 Hardman, G., potato acreage in Nevada, 150 Harvesting implements and their operation, 167 Harvesting potatoes with elevator digger, 170 Harvesting potatoes with plow, 168 Harvesting the California crop, 152 Harvesting the crop, 130 Harvesting the potato crop in the U. S., 166 Harvesting the seedlings, 411 Hastings, Fla., cultural practices, 82 Hawkins, L. A., leak disease, 270 Hebron group, 456 Henshaw, H., classification of Up- to-Date varieties, 471 Hill selection method, 424 Hilling or ridging, 132 Hogbacks or knolls as sites for storage house, 227 Home rs. foreign potato production, 2 Horse implements and their use, 168 Hotel and restaurant demands for special tubers, 187 How to cut seed, 58 How to select promising seedlings, 412 Howard's construction costs, 241 Humidity content of air in storage house, 210 Increased potato consumption desir- able, 360 Idaho Falls, Idaho, potato district, 149 Idaho production and commercial centres, 149 Idaho storage house construction, 242 Illinois potato production, 134 Illinois production centres, 135 Importance of aeration, 210 Importance of late or main-crop production in the South, 101 Importance of moisture to plant, 20 Importance of Southern crop, 92 Important production factors. 122 Indiana potato production, 134 Indiana production centres, 135 Industrial uses of the potato, 348 Influence of season on yield from large- and small-sized seed pieces, 56 Injury to tubers in harvesting, 189 Insect and animal parasites and their control. 290 Insecticides controlling leaf-chewing insects, 334 Insecticides controlling sucking in- sects, 338 Insecticides controlling tuber-eating pests, 341 Insulated potato storage houses, 233 Insulating pitted potatoes, 224 Intercropping, 39 Interior arrangement Aroostook, Me., type of storage house, 235 Interior arrangement of storage house, 232 Interplanting or intercropping, 39 Introduction into Europe, 371 Iowa potato production, 134 Iowa production centres, 135 Irrigating up, 85 Irrigation in Florida, 82 Irrigation practices in peat soils of West, 86 Jones, L. R., blackleg, 271 Jones, L. E., early blight, 249 Johnson, G. W., potato development in India, 381 Kansas production centres, and vari- eties, 140 Kentucky production, and commer- cial centres, 116 Kerosene emulsion, manufacture and use, 339 Kind of seed to use, 47 Kinds of unsound tubers, 212 King, F. H., moisture reciuirement of plants, 20 King's construction costs, 240 Kohler's variety classification, 437 Krantz's flower-stalk classification, 439 Kremers, E., potato distilleries, 35S Krichaufl, T. E., H. W.. early cul- ture in England. 379 Kunkel, L. 0., wart disease. 269 INDEX 509 Labor-saving device for moving bar- rels, 185 Land elevation: its relation to po- tato culture, 15 Langworthy, C. F., parts of tuber, 367 Late blight and its control, 254 Late blight losses, 247 Late blight rot in storage, 212 Late or main-crop potatoes in the South, 100 Late or main-crop production cen- tres, 122 Leading environmental influences in potato culture, 14 Leaf-chewing and mining pests, 290 Leaf-roll, 278 Leak disease of potato, 270 Le Baron, W., potato leaf hopper, 315 Leguminous plants as soil enrichers, 28 Lenne's variety classification, 436 Level culture, 75 Level culture vs. hilling or ridging, 132 Life historv of eehvorm, 319 Life history of late blight, 252 Life history of plant lice, 310 Life history of potato leafhopper, 315 Life history of potato stalk and stem borer, 298 Life history of white grubs, 302 Light in its relation to storage, 211 Lighting of storage house, 231 Limitations of breeding and selec- tion, 384 List of varieties with descriptions, 485 Localities producing genuine second- crop seed, 103 Localities w^hei'e potatoes are grown in Florida, 107 Locality where refrigerated storage might be used, 236 Location of Aroostook, Me., type of storage house, 234 Location of storage house, 226 Location of ventilators in storage house, 232 Long Island, N. Y., potato district, 127 Long Island, N. Y., production cen- tres, 129 Long Island, N. Y., soil and climatic conditions, 129 Long Island, N. Y., source of seed supply, 129 Losses in storage due to diseases, 247 Losses in storage from mechanical injuries, 212 Loudon, J. C, early potato culture in England, 379 Louisiana production and commer- cial centres, 113 Low cost of production, 156 Lutman, B. F., early blight, 250 Lutman, B. ¥., 20 years of spray- ing, 342 Macoun, W. T., strain tests, 429 Macrosiphum salonifolii Ashm., 309 Magnitude of crop, 1 Maine construction costs, 235 Manitoba potato production, 500 Market a factor in determining re- gions of greatest production, 122 Marketing early Southern crop, 100 Marketing potatoes successfully, 198 ^Markets for midwest states, 135 Markham, C, translation Chronicles of Peru, 370 Maryland potato production. 111 Mass selection method, 427 Mechanical potato sizers, 182 Melhus, I. E., late blight, 252 Melhus, I. E., powdery scab, 280 Merino, G., late blight, 251 Mertzel and Lengerke's Agricultural Calendar, 215 Metcalfe, C. L., flea beetle trap, 295 Method of applying commercial fer- tilizer, 33 Method of attack in black scurf, 263 Method of collecting and applying pollen, 402 Method of grading potatoes, 183 Method of growing and handling seedlings, 410 Michigan potato production and va- rieties grown, 136 Michigan, Wisconsin and Minnesota area, 136 ]\Iillardet, A., Bordeaux mixture, 325 Miller, P.. potato varieties listed in 1731, 379 510 INDEX Milward, J. G., early blight, 250 Milward's classification, 438 Mining pests, 290 Minnesota construction costs, 240 Minnesota potato production and varieties grown, 136 Minimizing handling to reduce tuber injury, 189 Minimizing tuber injury by proper operation of sizes, 192 Mississippi potato production, 112 Missouri potato production, 134 Mitchell, W. S., description of the potato, 374 Moisture requirement of potato plant, 20 Montana commercial varieties, 149 IMontana potato production, 148 More and Dorland, handling pota- toes, 195 Morris, 0. M., commercial centre in Oklahoma, 115 Morse, W. J., arsenoids, 338 Morse, W. J., blackleg, 271 Morse, W. J., powdery scab, 280 Mosaic disease and yield reduction, 277, 278 Motive power required to operate elevator type of digger, 170 Murphy, P. A., mosaic reduces yield, 278 Nebraska production centres, 138 Necessity of crop rotation, 38 Needs of the potato industry, 358 Net necrosis, 282 Nevada commercial districts and varieties, 150 Nevada potato production, 150 New Brunswick's yearly production, 500 New England and Northern New York potato area, 130 New Jersey potato districts, 127 New Jersey practice in handling newly dug potatoes, 175 New Jersey soil and climatic con- ditions, 129 New Jersey source of seed supply, 129 New Mexico potato production and commercial areas, 151 New York potato production (west- ern part), 131 Nineteenth century potato-breeding achievements, 384 Nitrogen in its relation to the po- tato crop, 27 I Nobbe, F., shrinkage in storage, I 214 Nobbe's experimental storage studies, 214 Non-elevator harvesting implements, 168 Non-parasitic diseases, 248 Nordman's cost data, 163 North and South Dakota, Nebraska and Kansas area, 138 North Carolina potato production, 109 North Dakota production centres and varieties, 140 Nova Scotia's jearly production, 500 Number of irrigations necessary to produce good crop of seed tubers, 85 Object of storage, 207 Objections to large sacks, 194 Occurrence and distribution of curly dwarf, 283 Occurrence and distribution of late blight, 251 Occurrence and distribution of tuber moth, 305 Occurrence of fusarium wilt, 256 Occurrence of powdery scab, 280 Ohio production centres, 135 Oklahoma production centres, 115 One-man potato planter, 65 Ontario's yearly production, 500 Operation of mechanical sizers, 184 Operation of one- and two-man planters, 65 Operation of the elevator digger, 170 Opinions on storage temperature, 208 Oregon production centres, 151 Oregon's commercial varieties, 151 Organic matter in soil, 23 Origin and earlv history of potato, 369 Orton, W. A., curly dwarf, 283 Orton, W. A., mosaic, 277 Orton, VV. A., streak, 275 Orton, W. A., verticillium wilt, 261 Osburn. H.. potato leafhopper, 315 Other British potato breeders, 392 INDEX 511 Parasitic diseases, 247 Paris green and its use, 334 Parisot, Dr., storage temperature, 208 Parts of a tuber, 367 Patch, E. M., potato aphids, 310 Paterson's potato-breeding work, 391 Peachblow group, 468 Pearl group, 466 Pelton's cost data, 162 Pennsylvania's potato production, 131 Per capita consumption, 358 Percentage of successful crosses, 404 Period of treatment with corrosive sublimate, 333 Period of treatment with formalin, 334 Phillips, H., potato development in Great Britain, 379 Phosphorus in relation to potato crop, 27 Picking and handling the tubers, 174 Planters in use, 65, 66 Planting in "tule" lands of Cali- fornia and Oregon, 90 Planting methods, 64 Plowing out potatoes, 168 Plowing the land, 24 Pollen viability, 395 Pollinating potato flower, 402 Poor handling of seed, 69 Poor stands, 69 Popenoe, E. A., potato stalk weevil, 300 Potash in its relation to potato crop, 27 Potato as a livestock food, 361 Potato-barley rotation, 43 Potato blossoming in Maine, 125 Potato breeding and selection, 384 Potato-breeding difficulties and tech- nic, 394 Potato breeding in Aroostook County, Me., 125 Potato breeding in Europe, 391 Potato culture in America, 381 Potato culture in France, 380 Potato culture in Great Britain, 379 Potato culture in India, 381 Potato culture in Prussia, 379 Potato culture in Sweden, 380 Potato culture in W. Va., 117 Potato diseases and their control, 247 Potato distilleries, 358 Potato exhibits, 478 Potato flour and its manufacture, 352 Potato grades and terms, 178 Potato grading and mechanical sizers, 182 Potato growing continuously, 41 Potato improvement by selection, 414 Potato leafhopper, occurrence and injury, 315 Potato plant lice, 309 Potato production costs, 156 Potato production in Canada, 11, 12 Potato production in North Amer- ica, 7 Potato production in the South, 92 Potato production in the United States, 2 Potato production in U. S. by geo- graphical areas, 12 Potato products, 348 Potato silage, 361 Potato sizers, 182 Potato sorting table or rack, 186 Potato stalk, and stem-borers, 298 Potato-stalk weevil, 300 Potato starch and its manufacture, 348, 352 Potato storage and storage shrink- age, 207 Potato trips, 482 Potato tuber moth, 304 Potato tuber parts, 367 Potato wart disease, 269 Potatoes after alfalfa, 42 Pounds of water to produce pound dry matter, 20 Powdery 'scab, 280 Pratt, 0., distribution of common scab, 265 Pre-germination tillage, 76 Preparation of Bordeaux mixture, 325 Preparation of seed bed, 26 Prince Edward Island's potato pro- duction, 500 Pringle's potato-breeding work, 387 Preventive measures for black scurf, 264 Preventive measures for common scab, 266 512 NDEX Preventive measures for e a r 1 v blight, 250 rreventivi' measures for fusariuni diseases, 260 Preventive measures for leak, 271 Preventive measures for silver scurf, 268 Preventive measures for verticil- lium wilt, 262 Preventive measures for wart dis- ease, 270 Production centres in the South, 90 Productive rs. unproductive hills (East), 419 Productive I's. unproductive hills (Eustace), 418 Productive rs. unproductive hills (Waid),419 Proper loading of hampers, 196 Proper loading of sacks or barrels, 195 Proper loading of summer ship- ments, 195 Proper loading of winter shipments, 196 Proper stage for emasculating flowers, 400 Provision for filling storage house, 233 Provision for ventilating pitted po- tatoes, 223 Putsch and Vertuch classification, 435 Pyrox as a fungicide, 331 Pyrox as an insecticide, 338 Quality of second-crop seed, 106 Quebec's yearly production, 500 Rainfall in its relation to potato crop, 21 Rand's potato-breeding work. 388 Rands, R. D., early blight, 250 Rate and distance of planting, 61 Receptacles used in gathering tu- bers, 175 Reclamation of "tule" lands in Cal- ifornia, 88 Reduction of mechanical injury of tubers, 172 Reed's description of tuber-bearing stolons, 365 Refrigerated ])otato storage houses, 236 Relation of commercial centres to markets, 199 Relation of rainfall to storage house. 230 Relation of size of seed piece to amount used, 55 Relation of size of seed piece to spacing, 64 Relation of sugar accumulation to temperature, 210 Relation of temperature and mois- ture to storage losses, 212. 218 Relation of temperature and mois- ture to tuber production, 15. 21 Relative importance of early, late, and fall crop, 93 Relative importance of potato crop in U. S., 3, 4 Relative magnitude of crop, 1 Remedial measures for Colorado beetle, 293 Remedial measures for common scab, 265 Remedial measures for eelworm, 320 Remedial measures for flea beetle, 295 Remedial measures for four-lined leaf -bug, 314 Remedial measures for plant lice, 312 Remedial measures for potato leaf- hopper, 318 Remedial measures for tliroc-liiuvl potato beetle, 290 Removing the potato seeds, 40!) Respiration and svntlicsis e(|nili- brium, 210 Resultant benefits from fungicides and insecticides, 342 Rhizoctonia or black scurf, 202 Riced potatoes, 355 Richter, W., potato breeding in Germany, 392 Ridge culture, 74 Roberts and Clinton iillage studies, 132 Roof construction of dugont storage house, 229 Rose group, 450 Round and Gore, potato silage, 361 Ruggles and Graham, potato leaf- hopper, 315 Rural group, 463 INDEX 513 Salamaii, R. N"., potato breeding, 401 San Luis Valley district, 147 Saskatchewan, yearlj' production of, 500 Schroeder's construction costs, 240 Schultz, E. S., powdery scab, 281 Score card, its use in judging, 479 Seasonal influence on size of seed I)iece, 56 Second-crop cultural practices in South, 103 Second-crop potato production in South, 103 Seed bed preparation, 26 Seed cutting, 58 Seed plot method of selection, 428 Seed potato containers, 192 Seed potato develoi)ment work, 428 Seed treatment after cutting, 60 Seed treatment with corrosive sub- limate and formalin, 333, 334 Selecting and preparing exhibition tubers, 478 Selecting promising seedlings, 412 Selection as a means of improve- ment, 414 Selection methods, 420 Seven-year crop rotation system, 43 Shape of pile in pit storage, 222 Shima, G., the potato king, 152 Shipping and marketing a business operation, 192 Shipping potatoes to distant mar- kets, 195 Shrinkage due to transpiration and respiration, 214 Silaging potatoes, 361 Silver scurf, 267 Size of Aroostook County potato crop, 123 Size of crop should influence time of selling, 202 Size of seed pieces, 54 Size of seed pieces on irrigated land, 57 Size of storage bin, 213 Size of tuber pile in pitting, 223 Skinner, R. P., alcohol production, 358 Sliced dried potatoes, 355 Slime mold, 248 Smith, W. J., climatic influence, 15 Snell's classification, 439 J 33 Sod walls in storage house construc- tion, 228 Soft rots, 273 Soil adapted to late crop in South, 101 Soil and climatic conditions in Long Island and New Jersey, 129 Soil for early crop, 96 Soil preparation, 24 Soil requirements, 14 Soil sanitation, 38 Soil types in tlie South, 97 Soils deficient in nitrogen, 27 Soils of Aroostook County, Me., 123 Solution of high cost of production, 164 Soundness of tubers stored, 212 Source of early blight infection, 250 Source of seed for L. I. and N. J., 129 Sources of Southern seed supply, 98 South Carolina, potato production, 108 South Dakota potato production, 138 Southern potato production graph, 94 Spacing of seed pieces, 62 Spacing of ventilators, 232 Special cultural features, 82 Species of fusarium, 257 Spindling sprout, 282 Spongospora subterrannea (powderv scab), 280 Spray equipment, 343 Spray equipment classification, 345 Stabilization of farm prices, 204 Starch imports, 351 Starch manufacture, 348 Starch variation in tubers, 417 Starch yields, 349 Stem- and tuber-eating insects, 290 Stewart, F. C, late blight losses, 247 Stockton, Calif., harvesting prac- tices, 176 Stone, J. L., level vs. ridge culture, 132 Storage capacity per cubic foot, 239 Storage cost, 239 Storage house arrangement, 232 Storage house humidity, 210 Storage houses proper, 225 Storage losses, 214, 218 Storage temperature, 207 Storage unsound tubers, 212 514 [XDEX Strain test studies, 429 Straw as an insulator and moisturu absorbent, 231 Strawberries with potatoes, 41 Streak, 274 Structure of pistil of potato flower, 396 Structure of stamens of potato flower, 397 Stuart, \V., potato breeding, 'M)'y Stuart's classification, 439 Student's potato-growing project, 475 Successful merchandising of crop, 156 Successful operation of an elevator digger, 171 Sucking insects, 291 Sugar accumulation in potato, 210 Suggestions for spraying plant lice, 341 Suggestive potato descriptive terms, 479 Suitable cars, lO" Sun scalding tubers, 174 Sweet potato storage house construc- tion, 234 Sweet ranch construction costs, 2.!'.) Sweet's type of storage house, 234 Symptoms of black scurf, 262 Symptoms of early blight, 250 sVmptoms of fusarium wilt, 2r)() Symptoms of leaf-roll, 278 Symptoms of verticillium wilt, 201 Systematized Bordeaux m i x t u r e making, 328 Systems of crop rotation, 38 Systems of culture, 74 Table of contents, IX Taft and Hcdrick, storage losses, 217 Technic in potato breeding, 39(5 Temperature conditions in relation to crop, 15 Temperature, storage, 208 Tennessee production and commer- cial sections, 116 Texas potato sizer, 185 Texas production and commercial sections, 114 The early or truck crop in the Soutli, 95 The fall crop proper, 102 The "Far-Western" states, 141 The five-eighth-bushel basket, 194 The potato essentially a northern crop, 121 The potato king, 152 The soil and its preparation, 23 Thermographic record sheets, 238 Thompson, H. C, sweet potato stor- age house construction, 234 Three-lined potato beetle, 296 Three steps in making Bordeaux mixture, 326 Three-year crop rotation system, 43 Tillage, 75 Tillage after germination, 78 Tillage studies, 132 Time of delivery of Northern seed in Soiith,'98 Time of planting fall and second crop in South. 106 Time to sell crop, 200 Tip-burn, 284 Tortoise beetles, 297 Tractor-operated sprav c(iuipim'iit, 344, 345 Transmission of productivity, 417 Treatment of seed, 332 Treatment of seed after cutting, GO Truax, H. E., potato grades, 178 Tuber-bearing stolons, 365 Tuber-eating insect control, 341 Tuber injiiry from common scab, 264 Tuber modification due to heat and drought, 16 Tuber moth injury, 307 Tuber unit selection method, 420 Tuber variations, 420 Twentieth century progress in breed- ing, 393 Twenty years of spraying, 342 Twin "Falls and Blackfoot, Idalw), districts, 149 Two-bushel or 120-pound sack con- tainer, 193 Two-horse riding cultivator, 78 Two important production factors, 122 Two-man planters, 65 Types of elevator diggers, 170 Types of mechanical sizers, 183 Types of planters, 65 Types of potato containers, 193 Types of storage houses, 221 Ultra-microscopic organisms, 248 United States Dept. Agr. storage house, 212 INDEX 515 United States potato grades, 17S Up-to-Date group, 470 Use of commercial fertilizers, ;!1 Use of farm manures, 30 Use of new l)urlap sacks, 193 Use of the two-horse riding culti- vator, 78 Use of the weeder and spike-toodi harrow, 76 Use of ventilated cars for sunuiier shipment, 197 Uses of potato starch, 349 Utah production and commercial centres, 151 Value of farm manures, 30 Van Orman's potato-breeding work, 390 Van (Slyke, L. L., chemical elements in plants, 27 Variation observations, 41(i, 420 Variations, tuber, 420 Varieties growing in "Far-Western" states, 141 Varieties growing in !Maine, 124 Varieties grown in N. D., S. D., Neb. and Kan., 140 Varieties grown in South for early crop, 97 Varieties grown in South for late crop, 101 Varieties grown in South for main crop, 101 Varieties grown in South for second crop, 103 ^'arieties listed: Acme (Early Acme). 5,' 456, 4S5 Acme (Walker's), 5, 4S.1 Acorn, 485 Admiral Foote, 485 Advancer. Vicks' Farlv, 6, 48") Albino (Early Albino,' etc.), 3, 48.1 Alpha, 485 American Giant, 8-2, 463, 485 American Wonder, 71, 485 Arcadia, 9-1, 466 Aroostook Beauty, 485 Babbitt, 8-1, 485' Badger State, 485 Banner (Livingston's Banner), 91, 466. 485 Banner, 485 Beauty (Brownell's Beauty). 485 IJeauty of Hebron (Earlv B. of H. ) , '6, 457, 485 Beauty of Hebron (Improved B. of ' H. ) , 6, 457 Beautv of Hebron (Late B. of II.), "6, 457, 485 Belle, 485 Bethel Beautv, 8-1, 463, 485 Bill Nve, 485 Bishop's Pride, 8-1, 463 Blight Proof, 81, 485 Blightless (Late Blightless), 8-1, 403, 485 Blightless Wonder, 8-1, 463, 485 Blue Victor, 10-3, 468, 485 Blush (Rural Blush, etc.), 485 Bovee ( Farly Bovee), 6, 486 Brown Beauty, HrowiU'U's Best, 486 Buuless (Gurncy's Bugless ) , 8-1, 463 Bull -Moose, 12,' 471 Burl)ank (Burbank Seedling), 7-1, 460, 486 Cambridge Pvusset, 7-2, 460 Carman No. 1, 82, 463, 486 Carman No. 3, 9-1, 466, 486 Charles Downing ( Idaho Kural ) , 486 Chicago Market, 5, 486 Clark's No. 1, 4-1, 451, 486 Clyde, 8-1, 463, 486 Colonel Stanlev, 12, 471 Columbus, 6, 457, 486 Conquering Hero, 12, 471 Cottar, 12, 471 Country Gentleman. 6, 457, 486 Crown Jewell, 6, 457 Cummings Pride, 12, 471 Dakota Red, 486 Dakota Seedling, 486 Dalhousie, 12, 471 Dalmeney Argon, 12, 471 Dalmeney Beauty, 12, 471 Dalmeney Helium. 12, 471 Dalmencv Hero. 12, 471 Dalmene'v Begent. 12, 471 Dearborn, IQ-l, 468, 486 Delaware. 8-1, 463, 486 Dew Drop, 3, 448 Dooley's, 91, 466 Doolin, John, 9-1, 466 Duchess of Buccleugh, 12, 471 Duchess of Cornwall, 12, 471 Early Acme, see Acme Earlv Albino, see Albino 1 The numbers in Black refer to the group to which they belong. 516 INDEX Early Beauty, 1, 445 J'^aily Bovee, see Bovee Early Dixie, 1, 445 JOarly Durham. 4-1, 451 JOarly iMireka, 1, 445 Early Fortuue, 4, 451 Early Harvest, 3, 448, 48() EarlV Harvest, 6, 486 Karlv Maine, 4-1, 451, 480 Karl'v Manistee, 4-2, 452. 480 Early Market, 5, 45(>, 487 Early Mayflower, 487 Early Michigan, 3, 448, 487 Early Norther, 4, 487 Early Ohio, 5, 456, 487 Earl'y Peaehblow, 11-1, 470 Early Petoskey, 1, 445 Early Prospect, 2, 448 Early Puritan, 3, 448, 4'.)0 Early Pvose. 4-1, 451, 487 ]':arly Six Weeks, 5, 456 Early Standard, 1, 445 Early Sunrise, 4-1, 451 Early Thoroughbred, 4-1, 451 Early Vermont, 4-1, 451 Early Victor, 1, 445 Early Walters, 4-1, 451 Early Waulionsie, 1, 445 Ehnola, 3, 448 Empire State, 8-2, 463, 487 Enormous (North Star), 81, 487 Enquirer, 12, 471 Eureka (Brownell's Eureka), 487 Eureka (Ex. Early Eureka), 1,445. 487 Everitt, 487 Excelsior, 487 Excelsior (Early Excelsior). 5, 487 ]']xcelsior ( Ex. Early Excelsior ) , 487 ]-:xtra Early, 487 ]5xtra Early Eureka, see Eureka Extra Early Fillbasket, see Fill- Extra Early Sunlight, 3. 448 lOxtra Early Vermont, 4-1, -151 Factor, 12,471 Farmer ( Farmer Hastings) , 81, 4{):!. 487 Fillbasket, 487 Fillbasket (Ex. Earlv Fillbasket), 4-1, 451, 487 First Earlv, 1, 445 Flourball, 1, 445. 487 Freeman, 8-1, 46:}. 487 tiarnot Chili, 487 Gem of Aroostook, 6, 457, 487 General Roberts, 12, 471 Gold Coin. 8-1, 403, 487 Gold Standard, 12, 471 Golden Harvest, 9-2, 400 Golden Rule, 9-2, 400 Golden Rural, 9-2, 40() Golden Russet, 7-2, 400, 487 Great Divide, 9-1, 400, 488 Green ^Mountain, 8-1, 4(i;}, 488 Green ^Mountain Jr., 8-1, 403, 488 Green ^Mountain, Lowell's, 8-1, 463, Hajjpy ^Medium, 1, 445 Harbinger, 6, 457, 488 Hart's No. 1, 9-1, 406 Hastings, see Farmer Heather Blossom, 12, 471 Heavyweight ( Everitt's H e a v y- weight), 488 Heavyweight (Mill's Heavvweight) , 488 Highlander. 12, 480 Honeoye Rose, 2, 448 Hoosier (not sj-n. of McCormick ) . 6, 488 Houlton Rose, 4-1, 451 Improved No. 5, 9-1, 460 Improved or Perfect Peaehblow, 11-2, 470 Irish Cobbler, 1, 445, 488 Irish Daisy, 1, 445 Isle of Jersey, 9-1, 466 Jackson White, 9-1, 460 Jersey Peaehblow (Old J. Peach- ' blow), 11-1, 470. 488 Jones Pink-Eved Seedling, 488 Joseph, 488 June Eating (Craine's June Eat- ing), 488 Junior Pride, 6, 457 Keeper (Craine's Keeper). 4SS Keystone, 8-1, 463, 488 Kiiig, 4-2, 452 King Loth, 12, 471 Klondike, 9-1, 488 Knowle's (Knowle's Big Croitper). 488 Late Beauty (Heath's L. B.), !M. 466 Late Blight less, 8-1, 403 Late Ohio. 5, 456, 488 Late Petoskey, 9-2, 460 Late Puritan, 7-1, 460, 400 Late Rose, 4-1, 451 Late Surprise, 9-1, 466 INDEX 517 Late Victor, 9-1, 466 Lee's Favorite, 4-1, 488 Lightning (Criiie'.s Lightning), 488 Lily ^^"hite, 9-1, 466 Long Ishmd W'under, 8-1, 46o Longfellow, 8-2, 463 McCormifk (Late Hoosier, Lookout ilountain), IM, 470, 488 McCormick (White McC'orniick ) , 11-1, 470 McGregor, 8-1, 463 McKinley, 8-1, 463 Maggie -Murphv (Queen of the West), 480 Magnum Bonuni, 480 Majestic, 5, 4r)6 IMammoth Pearl, 480 Manila, 9-1, 466 Manistee, 4-2, 452 Market Prize, 91, 466 Million Dollar, 91, -^^^G Mill's Pride. 81, 463 Milwaukee. 6, 457 Money Maker, 7-1, 460, 480 Moreton, 12, 471 Nebraska, 9-1, 466 Netted Gem, 7-2, 460 New Improved P e a c h b 1 o w (Nichol's), 11-2, 470 New Oregon, 8-1, 463 New Queen, 6, 457, 480 New White Peachblow, 11-2, 470 New White Victor, 1, 445 New Wonderful 7-2, 460 Nobleman, 12, 471 Non-Blight, 9-1, 466 Norcross, 8-1, 463, 489 Noroton Beauty, 2, 448, 489 North Star, 489 Northern Beauty, 4-1, 451 Nott's Peachblow, 11-2, 470 Noxall, 9-1, 466, 489 Ohio Junior, 5, 489 Ohio Wonder, 9-1, 460 Orange (Wall's Orange), 489 Pan-American, 9-1, 466, 489 ' Pan-American, 489 Peachblow (Ex. Early Peachblow), 11-1, 489 Peachblow ( Perfect Peachblow ) , 11-2, 470, 489 Peachblow (Thorburn's New W. Peachblow), H-l, 489 Pearl (Peerless), IQ-l, 468. 480 Pearl of Cannon Valley, 480 *Peerless (Bresee's No. 6 or Bos- ton), 9-1, 466, 489 People's, 10-2, 468, 480 I'ingree, 489 Potentate, 1, 445, 489 Potentate, 9-1, 466 Preparation of drj^ Bordeaux mix- ture, 331 I'resident Roosevelt, 12, 471 Pride, 8-1, 463 Pride of Multnomah, 7-1, 489 Prince Henry, 9-1, 466 Prize Earlv Dakota, 5, 456 Producer, 12, 471, 490 Prolific Bresee's (Bresee's No. 2), 490 Proper loading of cars, 195 Prosperity, 91, 466, 490 Puritan, Early, see Early Puritan Puritan, Late, see Late Puritan Quick Crop, 6, 457 Quick Lunch, 2, 448, 490 Patckin's Red River Special, 5, 45(i Rehoboth, IQ-l, 468 Rhind's Hybrid, 9-1, 466 Rochester Rose, 4-1, 451 Rural New Yorker No. 2, 9-1, 466. 490 Russet Burbank, 7-2, 460, 490 Russet Rural, 9-2, 464, 490 Rustproof, 8-2, 463, 490 Rusty Coat, 7-2, 460 Scabproof, 7-2, 460 Scottish Monarch, 12, 471 Scottish Triumph, 12, 471 Seneca Beauty, 490 Sensation, 9-1, 466 Sensation, 12, 471 Silver King, 8-1, 463 Silver Skin, 490 Sir Mark Stewart, 12, 471 Sir Walter Raleigh, 9-1, 466, 490 Snow. 8-1, 463, 490 Snowflake, 490 Solanum species from S. A.. 12, 471 Somer's Extra Earlv, 4-1, 451 Spaulding No. 4, 4-2, 452. 490 Star-of-the-East, 6, 457, 490 State of Maine, 8-2, 463, 491 Superlative, 12, 471 Surprise (Early Surprise), 1, 491 Table Talk, 12* 471 Talisman. 12, 471 Not the true Bresee's No. 518 INDEX Thorlmrn, 4-1, 451, 491 Todd's Wonder, 9-!, 466 Triumpli, 2, 448, 491 Trust Buster, 1, 445 Uncle Sain, 8-1, 4fio, 401 Uncle Sam, 9-1, 466 Verljots (from S. A.h 12, 471 Victor (Early Victor), 1, 445, 491 Vigorosa, 6, 457 Warrior, 12, 471 Washington, 8-1, 463 White Elephant, 6, 457, 491 White Giant, 9-1, 466 White Globe, 9-1, 466 White Harvest (Gnrney's W. H. ) , 8-1, 463, 491 Whho Hebron, 6, 457 White Mammoth ( Whiton's W. M.) , 8-1, 491 White Ohio, 5, 456, 491 White Rose, 4-1, 451, 491 ^^"hite Star, 7-1, 491 White Swan, 9-1, 466 White Triumph, 2, 448 Wood's Earliest, 2, 448 World's Wonder, 9-1, 491 Varieties to grow, 46 ^'entilated storage house floor, 232 Ventilation for pitted tubers, 223 Ventilation in storage house, 211, 231 Ventilator construction, 232 Verticillium wilt, 261 Vilmorin, Ph. de., early culture in France, 380 Vilmorin's activities in France, 392 Vilmorin's classification, 436 Virginia production, 119 ^^'aid, C. W., high- and low-yielding plants. 410 \\'all construction of storage liouses, 229 Wart disease, 269 Washington production and com- mercial centres, 151 Water transportation quickest and safest, 197 Watson, J. F., early record potato culture in America, 381 Webber, H. J., tuber-unit method, 420 West Virginia production and com- mercial centres, 117 \\estern New York and Pennsyl- vania region, 131 Western type of mechanical sizer, 184^ Westover and Rowe, soils of Aroos- took Co., Me., 123 Whale oil soap, 340 When should a grower scH, 200 When to cut seed, 59 White grubs, habits and life history, 302 Why import starch, 351 Widtsoe, J. A., moisture require- ments of plants, 20 Wight, W. F., early history of the potato, 369 Wight's comments regarding ^'ir- ginia origin, 372 Wing potato hoe, 78 Winter shipments by rail, 196 Wireworms : habits and life history, 304 Wisconsin production and varieties grown, 136 Wortlev, C. J., mosaic reduces yield, 278 Wright and Castle, storage tempera- ture, 208 Wyoming production and commer- cial centres, 147 Yearly and average production by Cajiadian provinces, 500 Yearly and average production by states, 492 Yields fnmi fall and second-crop idanting, 106 Zcllcr, P. C, potato tuber moth, 305 Zone car movement in Aroostook Co., Me., 126 North Carofina State POTATO ITS CULTURE USES HISTORY Libraries CLASSIFIC