le Rural Scienc LH.Bail I ley .£ mife ^. % pU pbrarg ^aril; Carolina ^taic College .^^ Date Due mi'23 ^ I' ^^:^? :n3'30L 25Feh'5f ^ J la ;ri A '^"^ - 5 iSJ ]S )8^ov'58 H 1 Apr' 60 i ,f^.v>r V if^'Qi ■■w ""PBBI NOV ^ ) b/; 71^ / ilV 1 - "7 ■ , . - r,^ r L. B. Cat. No. 1137 Ube IRural Science Series Edited by L. H. BAILEY CITRUS FRUITS Eije Eural . Mrs. L. C. Tibbet, who first brought the true Navel orange to California 18 4. One of the two original Washington Navel orange trees brought to California 21 5. California citrus areas 27 6. Four-year-old Valencia orange grove in Los Angeles County 28 7. Typical scene in Los Angeles County. Windbreak of Gre- villea robiista on right 35 8. Finns radiata, a native pine, used as a windbreak . . 36 9. Orange tree denuded of foliage on windward side by three days of desert wind 37 10. Growth rings in a flattened brace-limb of lemon ... 47 11. Result of experiment which shows that a girdled orange tree may grow new bark. A. Untreated ; B. Treated . 48 12. Valencia orange blossoms 53 13. Lemon blossoms showing perfect, partly aborted and aborted pistils. Stamens removed in latter case ... 54 14. Orange flower x 2. p, pistil ; a, stigma ; c, style ; o, ovary ; s, stamen ; b, anther ; e, filament ; d, nectary ; g, sepal ; /, petal 57 15. Polyembryony. Two orange seedlings from one seed . . 60 10. The earliest known illustration of a Navel orange. From Ferrarius' " Hesperides," 1040 67 17. One type of Australian Navel orange 69 18. Eureka lemon, uncured 73 19. Lisbon lemon, uncured 75 XV xvi Li.si of Illustrations FIG. PAGE 20. Seedless pomelo, flowers and fruit. From Volckamer's " Ilesperides," 1708 70 21. Dancy Mandarin orange 78 22. Satsuma Mandarin orange 80 23. Nagami kumquat 82 24. Citrus seed-bed under lath 85 26. Citrus seed-bed in the open 89 26. Bench-rooted orange seedling 90 27. Orange bud-wood 98 28. Cutting a bud 96 29. Making incision in stock 97 30. Inserting bud 98 31. Tying inserted bud 99 32. Orange buds in nursery row tied to lath stakes . . . 101 33. Healing of the bud union 103 34. Balling orange trees in the nursery 104 35. A shipment of defoliated balled orange trees . . . 108 36. Two-year-old orange trees, balled, ready for market . .112 37. Type of standard Washington Navel orange . . . .117 38. Washington Navel oranges showing fluctuations in the navel. Such variations cannot be preserved by budding . .119 39. Variegated sport. Note white areas in leaves. From Volck- amer's " Hesperides," 1695 121 40. A variegated sport of Valencia orange. Notice white margin of leaves 122 41. Sectorial chimera of Valencia orange 124 42. Orange showing sectorial chimera. From Ferrarius' " Hes- perides," 1646 126 43. What is known as the " Wrinkled" sport of Eureka lemon compared with normal fruit. Both from same tree . 127 44. Chart showing by dotted line the small proportion of profit- able trees, and by heavy line the large proportion of trees which only pay for their care. West Highlands Orchard. (Adapted from Norton) .... 129 46. Cow peas as an intercrop in young lemon orchard . . 153 46. Breaking a layer of hardpan by means of a stick of dynamite discharged in each tree hole 156 List of Illustrations xvii FIG. PAGE 47. Newly set tree properly protected from sun .... 158 48. Cultivating newly set orange trees with eight-chisel cultivator 166 49. Cloddy condition due to land being worked while too wet . 167 50. Ground under trees worked with ease by means of orchard tractor 169 51. Orchard tractor doing the work of eight mules in a hot desert valley 171 52. Heavy plowing with an orchard tractor of the caterpillar type 173 53. Substituting baled lima bean straw for manure in lemon orchard near Whittier, California 176 54. Cull oranges used as a humus-forming fertilizer . . . 180 55. Canal lined with cement. Transformation of desert hills into orange groves 187 56. Preparing the ground for furrow irrigation. (From U. S. D. A. Farmers' Bid. No. 404) 190 57. Irrigating stands in operation 194 58. Zigzag furrows for wetting the ground between the trees . 197 59. Overhead irrigation system in old orange orchard near Covina, California 199 60. King soil sampler. Of use when irrigating .... 202 61. A well pruned Eureka lemon orchard. Photographed, August 10th, near Alhambra, California . . . 205 62. Prototype of California pruning saw. From Volckamer's " Hesperides," 1708 207 63. " California " pruning saw, used throughout southwest . 208 64. Good type of pruning saw above ; poor type below . . 210 65. One of the best types of pruning shears . . . .211 66. Vigorous fruiting brush gi-owing in the place of suckers . 212 67. This extra vigorous shoot terminated at six inches with a fruit showing that excess of food did not change it into a sucker 214 68. A sixty-acre three-year-old Valencia orchard top-worked to lemons. The paper bags protect the buds from rose beetles 215 69. Fifteen months' growth on stocks shown at Fig. 68 . . 216 70. Three-year-old Navel head on top-worked sweet seedling . 221 xviii List of Illustrations VUi. I'AGK 71. Prunine; a frosted lemon orchard 222 72. A. Normal vesicles of lemon. Ji. Enlarged vesicles from frosted fruit six months after injury .... 230 73. Frost splitting of bark on fruiting brush of lemon . . 241 74. Three-year-old trees protected with cornstalks . . . 245 7o. Screen of tobacco cloth as a frost protection . . . 246 76. Big six 247 77. Eichhoff coal burner 248 78. Hamilton down-draught 249 79. Bolton . • 250 80. Coe 251 81. Pomona pipe-line heater 251 82. Dunn 254 83. Canco 255 84. Kayo 25t) 85. Hislop 257 86. Hamilton reservoir 258 87. Troutraan 258 88. Adamson torch 25!) 89. Coal-burning orchard heaters. Fuel stored in boxes under trees 261 90. Orchard heaters ready for lighting . ... 262 91. Orchard heaters in old Valencia grove .... 263 92. Placement of orchard heaters. Extra fuel in cans under trees 265 93. The perforated stack gives good combustion but may admit rainwater 266 94. The water separator for frosted fruit . . . . 271 95. Thermometer station of the Pomona Valley Orchard Pro- tective Association 275 96. Tuttle fruit clippers with rounded points .... 279 97. Dashboard picking bag 280 98. Co Vina picking bag 281 99. Woodward picking bag 282 100. The Wiss clipper now being sajxTseded by tin- 'i'uitle shown at Fig. 96 283 101. Metal attachment for propping up limbs .... 283 List of Illustrations xix ri'J. PAGE 102. Worm brushes used for polishing oranges .... 284 103. Rope feed hopper 285 104. Orange sizing machine . . . . . . . 286 105. Box press and naiHng machine . . . . • , . 287 106. Citrus fruit truck 288 107. Packing stand 289 108. Box-squeeze, small size 290 109. Car-squeeze, large size 291 110. Interior view of the Pioneer Fruit Co.'s orange packing house at Lindsay, California 294 111. Orange packers at work 296 112. A typical orange box label 299 113. General aiTangement of orange packing house . . . 300 114. Picking lemons 302 115. Two-story lemon packing house, Glendora, California . 304 116. Lemon washing machine and sorting table .... 307 117. Lemon curing tents in packing house near the coast . . 309 118. Truck for handling trays of ungraded lemons . . . 310 119. Packing lemons from sorting trays . . . . .311 120. Lemon packing house, second floor and elevation . . 314 121. Typical lemon box label 315 122. Combination box label 316 123. Fumigation scars 322 124. Scar caused by rubbing on the ground .... 323 125. Orange splits. Side splits above and Navel end splits below 327 126. Horizontal cracks are very different from splits . . . 328 127. Peteca of lemon 329 128. The Fawcett method of treating gum disease. Note types of scrapers 365 129. Reddish gum areas on under side of leaves caused by sunburn 368 130. Exanthema pustules on Valencia orange twigs . . . 370 131. Mottled-leaf disease on Eureka lemon .... 375 132. Advanced stage of mottled-leaf disease showing multiple buds 377 133. Spot caused by wither-tip 380 134. A " ne.st " of cottony fungus 384 XX List of llludrations Fl<;. PACK 136. Black rot of Navel 388 136. Brown spot of Navel orange 390 137. Stem-end spot of orange 399 138. Pruning stub on orange tree infected with xchizophylhim . 400 139. Black scale on orange twig 400 140. The red scale on orange 411 141. Work of red scale on orange tree 413 142. The purple scale enlarged 416 143. Cottony cushion scale 417 144. Citrus mealy-bug 422 145. Scars due to citrus thrips 426 146. Fuller's rose beetle 429 147. The work of Fuller's rose beetle 429 148. Scars on rind of orange caused by katydid .... 430 149. A fumigation demonstration 432 150. Method of marking fumigating tent 436 151. Flashlight picture of marked fumigating tents . . . 442 CITRUS FRUITS CITRUS FRUITS CHAPTER I HISTORY AND DEVELOPMENT OF THE CITRUS INDUSTRY IN THE SOUTHWESTERN UNITED STATES Citrus seeds were first brought into California from the peninsula of Lower California, where peoples of Spanish descent have cultivated various kinds of European fruit trees and vines since the year 1701. In 1768 the Jesuit missionaries were supplanted by the Franciscans, some of whom under the leadership of Junipero Serra pushed northward into the territory which is now the state of California. These hardy pioneers founded the first mission in Upper California at San Diego in 1769, and proceeding northward established a chain of missions extending four hundred miles along the coast, the last being established at Somoma in 1823. At a number of these missions, vineyards and orchards were planted. Cuttings of grapes and figs, and seeds of oranges, pomegranates, citrons, olives, pears, dates, and other fruits were brought from the older missions on the peninsula. At several missions the remnants of the old orchards may still be seen, partly inclosed by the adobe walls which were built to protect the trees from wandering herds of cattle. B 1 2 Citrus Fruits The San Gabriel Mission near the present city of Los Angeles, by reason of the abundance of water and the large number of neophytes brought into service, gained rapidly in wealth and productiveness. The exact date when orange seed were first planted at this mission is not known, as the archives of the mission church are lost. It is certain, however, that the first California orange orchard of any size occurred at San Gabriel, and various writers agree that this orchard must have been planted in 1804 or the following year. This first orchard covered about six acres of ground and was composed of about four hundred seedling trees, a few of which were still bearing in 1885. Although this orchard was not planted for financial gain, and it is doubtful if any fruit was ever sold from it, the success of this pioneer planting established the fact that the climate and soil conditions were quite favorable to the production of citrus fruits. Soon orange trees distributed from the missions began to be planted in court-yards and gardens in various places, the fruits being either all consumed at home or given away to friends. Perhaps the largest number of trees in any private garden were the thirty-five trees transplanted from San Gabriel about the year 1834 to Aliso Street in Los Angeles, by Don Louis Vignes. It remained, however, for William Wolfskill, a Kentucky trapper of German blood, who had come to Los Angeles overland in 1831, to forecast the commercial possibilities of this fruit. Wolfskill secured orange trees from the San Gabriel Mission in 1841 and planted a two-acre orchard in what is now the city of Los Angeles, on the spot now History and Development of the Citrus Industry 3 occupied by the Arcade passenger station of the SouthgEjii Pacific Railroad. The fruit from this orchard sold to such advantage that it was increased in size to about twenty-eight and finally to seventy acres. It is said that Wolfskin was the first to ship a full car of oranges to Eastern markets. They were sent to St. Louis in 1877 and arrived in good condition after having been a month in transit. The freight charge is said to have been $500. The last crop disposed of in his lifetime sold on the trees for $25,000. The success of the Wolfskill orchard stimulated others, and in 1853 Matthew Keller secured orange seeds from Central America and also from Hawaii. From these he raised young trees with which he planted an orchard opposite that of Wolfskill . In 1 857 L. Van Leuven planted orange trees at Old San Bernardino, and in the same year L. F. Cram planted a small orchard at Highlands. Myron H. Crafts planted two hundred orange trees at Crafton in 1865. In September, 1870, J. W. North of Knoxville, Ten- nessee, bought four thousand acres of desert land which is now occupied by the city of Riverside. Judge North carried on an advertising campaign in the Eastern states to attract colonists to this land. Settlers began to arrive the following winter, and in the spring of 1871 the first orange seeds were planted. This means of settling the country was used in various parts of California. Pasadena was first known as the Indiana Colony, the lands being purchased in 1873, distributed in 1874, and orange orchards planted as soon as the ground was leveled and irrigation water provided. Citrus Fruits Frank A. Kimball planted orange and lemon trees at National City in San Diego County about 1870. A large proportion of the trees planted at this time were purchased from the nursery of T. A. Garey in Los Angeles (Fig. 1). Garey imported a large number of varieties from various places during the years 1868 to 1875. He is said to have received shipments of trees from Australia, southern Europe, and Florida, as well as from the nurseries of Ellwanger and Barry of Rochester, N, Y., and Sir Thomas Rivers of Sawbridge- worth, England. The fruit from these primitive or- chards was either consumed in the neighborhood of its production or hauled to Los Angeles and there shipped to northern ports by water. Southern California still lacked railroad connec- tion with the Eastern markets and there was no incentive to grow more oranges than sufficed for local consumption. Orange trees were first planted in the central and northern part of California in the early sixties. The first 1. — Thomas A. Garey, citrus nurseryman. History and Development of the Citrus Industry 5 planting of which we have record was at Bidwell in Butte County in 1859. In a great many cases these early plantings proved successful, and it w^as soon apparent that areas of greater or less extent, suitable for the growth of citrus fruits, existed in many scattered locations all the way from San Diego in the south to Shasta County in the north. The commercial development of citrus culture may be said to have begun with the completion of the Southern Pacific Railroad's connections w^ith the East. The Valley line w^as completed in 1876 and the Southern line to New Orleans in 1881. The exhibition of the first fruits of the Washington Navel orange at Riverside gave another impetus to citrus planting, but the greatest development came with the completion of the Santa Fe's competing line of railroad, which was opened up about 1885. The first special train loaded exclusively with oranges left the River Station, Los Angeles, February 14, 1886, for the East via the Southern Pacific and Union Pacific Rail- roads. In February ,1879, what was probably the first of a series of annual citrus fairs was held at Riverside. The differ- ent citrus-growing communities of southern California took great interest in these fairs, and the prizes together with the prestige which they carried were vigorously competed for. It was at these early citrus fairs that the great superiority of the Washington Navel orange, the history of which is given on another page, became appar- ent. The climate and soil conditions in California proved eminently suited to this variety of orange, which here at- tained a perfection truly marvelous. The strong demand 6 CHrm Frnitu for these oninges in the Eastern markets and the liigh priees reeeived by some brought on a period of frenzied phmting and specuhition. A great deal of worthless nurs- ery stock, quickly and cheaply grown on Chinese lemon roots, w^as planted, and many orchards were set out on lands more or less unsuited to citrus culture. This wave of rapid expansion culminated in 1885-86, when drouth, frosts, scale insects, and the lack of a coherent marketing organization conspired to rudely awaken from their golden dreams many who had rushed into the business with insufficient knowledge and capital to weather a period of depression. In 1884, at the Cotton Exposition held in New Orleans, the twenty varieties of oranges grown and exhibited by Riverside took first premium in competition with the world. This fact was heralded far and wide and proved of great value in advertising the California citrus business in general and Riverside in particular. In the early days of the industry there was no adequate horticultural inspection or quarantine service, and as a consequence a number of kinds of very destructive scale insect pests were introduced on nursery stock imported from various parts of the world. In this way the cottony cushion scale (Icerya jmrchasi) was introduced from Australia in 1868. In twenty years this scale spread throughout the orchards of Los Angeles County. So serious was this pest that the industry, in Los Angeles County at least, was on the verge of extinction. In the spring of 1888 Albert Koebele was sent to Aus- tralia by the U. S. Department of Agriculture to study the cottonv cushion scale in its native land. The follow- History and Development of the Citrus Industry 7 ing year Koebele succeeded in introducing the Novius cardinalis, a small predaceous ladybird beetle, which at once attacked the scale and preyed upon it to such an extent that it was checked in its spread, and in many localities it was almost exterminated. As a consequence, in 1891 , the shipments from Los Angeles County suddenly increased from 7S1 to 2212 cars, a net gain of 1431 cars, due, at least in large part, to the good work of the ladybird. Since the introduction of this predaceous beetle the white scale has been held in check and is not now feared by citrus growers. The fight with the cottony cushion scale had hardly been won, however, when other difficulties appeared. Al- though the orchards produced large crops it became more and more difficult to successfully market the fruit. The season of 1892-93 was particularly disastrous as far as net returns were concerned. The growers were not organized, and as long as each grower attempted to market his own fruit he became an easy prey to the miscellaneous assortment of commission men, agents, and speculators who at that time infested the markets and who in many cases, it is said, secured secret rebates from the railroads. In Riverside and in all the older sections, where there was any quantity of fruit to ship, account sales in "red ink" were received without number, and it frequently happened that the larger crop a grower had, the more he was in- debted to his packer at the end of the season. As a result of these failures to successfully market large crops, a few of the growers began to associate themselves together for mutual protection and to provide better packing facilities. Stimulated by the success of some of these associations in 8 Citrus Fruits gainiiifj concessions from the railroads and in many otliet ways securing better returns for their members, a hirge percentage of the growers assembled at the Chamber of Commerce in Los Angeles on April 4th, 1(S93, the declared purpose of the meeting being : "To jjrovide for the mar- keting of all the citrus fruit at the lowest possible cost under uniform methods, and in a manner to secure to each grower the certain marketing of his fruit and the full average price to be obtained in the market for the entire season." At this meeting a cooperative packing and marketing organization w^as formed, which, while not entirely satisfactory, was a great improvement over the old methods and served to prepare the way for the Southern California Fruit Exchange, which was organized October 21, 1895. At first the Plxchange handled about 32 per cent of the total shipments, but the proportion of the crop handled has gradually increased till at the present time the Exchange ships about 62 per cent of the total crop. On ]March 27, 1905, the California Fruit Growers' Exchange was incorporated, and on September 1, follow- ing, succeeded to the business of the Southern California Fruit Exchange, this change in name being deemed advisable in order that the marketing organization itself might in name as well as in fact become general through- out the state rather than remain local to southern Cali- fornia. The Exchange is now an association of three groups or classes of organizations : the one hundred and fifteen local associations ; the seventeen district exchanges ; and the central exchange. For a detailed description of this rather complex organization see pages 345 to 353. History and Development of the Citrus Industry 9 California Citrus Shipments Season Cabloads Season Carloads Season . Carloads 1890-91 4016 1898-99 10875 1906-07 29820 1891-92 4400 1899-00 18400 1907-08 32729 1892-93 5871 1900-01 24900 1908-09 40592 1893-94 5022 1901-02 19180 1909-10 32648 1894-95 7575 1902-03 23871 1910-11 46394 1895-96 6915 1903-04 29399 1911-12 40673 1896-97 7350 1904-05 31422 1912-13 18960 1897-98 15400 1905-06 27610 1913-14 48548 Not the least important factor in building up the citrus industry has been the protective duties imposed upon citrus imports by the Congress of the United States. Such protective duties have prevailed since July 4, 1789, when a general tariflf bill was passed which included a 5 per cent ad valorem duty on all citrus fruits. Since that time the duty has been gradually, though not uniformly, increased by the enactment at different times of nineteen changes in the law. By the Underwood-Simmons tariff act, effective October 4, 1913, the duty is one-half cent per pound on oranges, lemons, pomelos, and limes. Orange peel or lemon peel, preserved, candied, or dried, one cent per pound ; citron or citron peel, preserved, candied, or dried, two cents per pound. Citric acid, five cents per pound. Citrate of lime, one cent per pound. Orange and lemon oil, ten per cent ad valorem. Bergamot, neroli, or orange flower oil, twenty per cent ad valorem. The free list includes fruits in brine ; lemon, lime, and sour orange juice containing not more than two per cent of 10 Citrus Fruits alcohol ; and orange and lemon peel not preserved, can- died, or dried. California citrus culture, among all horticultural in- dustries, is peculiar in that the people who have built it up have been, in many cases, retired business men or professional men from the New England and Central states. Persons who have lost their health in the process of gaining wealth have bought and developed citrus proj^erties, the management of which, by requiring a life in the open sunshine and dry air, has resulted in renewed health and steadied nerves. These people brought to the industry much needed capital, commercial habits, and business ability. Citrus culture appeals to people of intelligence and refinement, and such are being drawn from many occupations. Now since the automobile has come into such general use, the wealthy business man of the city builds a residence in his orange orchard in the suburbs, while along the interurban electric lines may be found the small orchards of the superannuated minister, the retired high school teacher, the lawyer, the doctor, as well as of those drawn from other walks of life. The result of this has been the development of an in- dustry characteristically American in spirit and new in methods. The sons and grandsons of pioneers from the West and middle West have little regard for the precedents and practices of the Old World citrus-producing regions. European methods are practically ignored in systems of cultivation, irrigation, and pruning. In their readiness to organize among themselves along business lines and work together for the better picking, packing, and mar- keting of the fruit, the CaHfornia citrus growers are History and Development of the Citrus Industry 11 probably in advance of any other class of fruit growers on earth. The citrus industry has also been greatly benefited by various government agencies, whose endeavor has been to increase knowledge through scientific investigations and disseminate this new information through free lectures and pamphlets, by experiment farms, and by operating for months at a time free demonstration trains on the railroads. There have been three principal agencies engaged in this work : the University of California Agri- cultural Experiment Station, the United States Depart- ment of Agriculture, and the State Horticultural Com- mission. The university work may be said to have begun with the analyses of oranges and lemons in 1885 and con- tinued to date, covering a multitude of problems affecting the industry. The university conducts a special corre- spondence course on citrus fruits for the benefit of growers everywhere. The agents of the Department of Agricul- ture have rendered valuable service to the industry in many ways. The State Commission of Horticulture has done much good work in preventing the entrance into the state of new pests and checking the spread of pests al- ready introduced. It has distributed many valuable publications, the one prepared by Lelong ^ in 1902 being of special value to the industry. A large number of strong, loyal agricultural and horti- cultural periodicals throughout the state have broad- casted useful information and fanned the flame of popular interest. Still another upbuilding agency has been the Chambers 1 B. M. Lelong, "Culture of the Citrus in California," 1902. 12 Citrus Fruits of Commerce in the various towns and cities. By main- taining interesting and attractive exhibits with free stereop- ticon lectures for visitors and tourists, and by preparing large exhibits for distant expositions, they have done a great deal to advertise the industry. Citrus culture in California will always be a popular occupation be- cause it appeals to a man from so many sides. It appeals to his love of the beautiful ; beck- ons him to health- ful outdoor life ; stimulates that inborn desire in man to make things grow ; sat- isfies his appetite, and last, but by no means least, it tempts him with offers of large financial rewards. Successful citrus culture calls for a combination of the science and the art of horticulture ; requiring both skill and industry, it gives healthful occu- pation to the mind as well as the*body. While a good many seedling orchards still persist in the older sections, they are gradually yielding (Fig. 2) to the activities of the woodchopper. Fig. 2. •The passing of the old seedling orange groves. History and Development of the Citrus Industry 13 HISTORY OF THE WASHINGTON NAVEL OR B.IHIA ORANGE The earliest illustrated description of a Navel orange on record was published in Rome by a monk of the Society of Jesus, John Baptiste Ferrarius, in 1646, in one of four books called "The Hesperides or About the Golden Apples, Their Culture and Use." The picture reproduced on page 52 of Lelong's "Culture of the Citrus in California," from John Johnson's book, will be seen on close comparison to be an artful copy from Ferrarius. This was certainly not the Washington Navel as we have it to-day, but merely one of the many Navel forms which have ap- peared from time to time. It is not unlikely that still other kinds of Navels will appear in the future. Orange trees were taken to Brazil by the Spaniards at a very early day and were more or less widely planted in those parts of the country best suited to their culture. Some time about the year 1820 or possibly earlier there appeared near the village of Bahia a form of Navel orange which was remarkable for its many good qualities. This was what we now know as the Washington Navel. It was hastily propagated and planted to a considerable extent. Specimens were sent to London and the form became known abroad under the name Bahia, after the village where it originated. At Bahia it was called simply " Lavanja de Umbigo.'^ Circumstantial evidence from several directions all points to the probability that from the very beginning one characteristic of this Navel orange was to produce occasional branches which bore fruit differing from that of the rest of the tree. In this wav a modified form came 14 Citrus Fruits into existence, the fruit of which was scant in amount, large in size, with a coarse exterior, and interior full of rag. Unwittingly this form was propagated along with the true Bahia. After years of experience the best Brazil- ian growers became aware of this sporting habit and were careful to select buds for propagation from the best type only. The peasants, however, did not comprehend tjje situation, and as the demand increased, continued to cut bud wood indiscriminately. On account of the pub- licity given the fruit sent to London, a trade in nursery trees sprang up. Agents from Rio de Janeiro went to Bahia and secured what was available, including both the prototype and the false type. Thus it is natural to suppose that the stock on the Rio de Janeiro market must have consisted of some lots of Bahia, some of false Bahia, and some mixed lots. There is a tradition that this Bahia Navel was intro- duced into Florida some time previous to 1835, but that the trees were killed in the freeze of that year. It is said that the Bahia Navel was introduced into Cape Colony, South Africa, by a Mr. Brehm of Uitenhage about 1840. The subsequent record of these trees shows that Brehm 's importation consisted entirely of the false form. On this account the Bahia was held in ill repute in South Africa, until between 1894 and 1900, when a number of importa- tions of the true Bahia were made direct from California. The fruit of these has been found equal in every respect to the best California product, and most of the old orchards have now been budded over. From Brazil the Sweet orange was first introduced into New South Wales, Australia, by Captain Hunter, who ac- History and Development of the Citrus Industry 15 companied Gen. Arthur Phillip at the founding of the colony in 1788. Orange growers in Australia early introduced the Bahia Navel direct from Brazil. One writer in 1858 states that Navel oranges were for sale in Australian markets, and that they brought a much higher price than other varieties. I have been unable to discover the exact date of introduction, but oranges were exported in consideralDle amounts from New South Wales in 1860, and it is perhaps safe to assume that at least a part of these were Bahias, since a writer in the Victorian Farmer's Journal in 1862 states that on account of the high prices received, the "Bahia Navel" was largely grown. From these state- ments it would seem that the date of the introduction of the Navel into Australia should be given as not later than 1850. Australian writers are not unanimous in praise of the Navel and this indicates that both the true and the false form existed there as early as 1860. We may con- clude, therefore, that this orange was grown commercially and was marketed under the name of Bahia or Navel orange as early as 1860. S. B. Parsons, a nurseryman of Flushing, Long Island, owned a small nursery at Blue Spring, Florida. Wishing to secure this Bahia Navel for propagation and sale, he ordered trees in 1868 from Thomas Rivers, a large nurs- eryman of Sawbridgeworth, England, who had received his stock from the Azores, to which place they were said to have been brought from Brazil. (In all probability they were not.) This orange proved not to be the Bahia Navel, and has since been known as the Parsons Navel. Thomas Rivers also sold some of the same lot of trees to 16 Citrus Fruits A. B. Chapman of San Gabriel, California, in 1870 or 1871. Some of these were propagated and sold by Mr. Chapman as the Rivers Navel. Thomas A. Garey, a well-known California nurseryman and author of a book on orange culture,^ established a citrus nursery in Los Angeles in 1865. Some of his asso- ciates now living inform me that he imported citrus seeds and trees from Australia, Mexico, Central America, and southern Europe. He is said to have secured the Navel in 1870, and it is an open question as to where he got it, with the probability strongly in favor of Australia. I have a copy of his catalogue dated 1876, in which he lists it as " Bahia Navel, " but cautions his customers against its shy bearing. Some persons who bought trees from him at that time condemn them as worthless, while others claim that they were identical with the Washington Navel. Garey must certainly have secured at least a preponder- ance of the false type of Navel. In 1873 J. C. Wallace of Los Angeles imported four Navel trees from Australia, all of which proved to be the false form and have been budded over. From this time this false form of Bahia Navel became known in California as the "Australian Navel" to distinguish it from the true Bahia. The Parsons Navel trees distributed by A. B. Chapman under the name of Rivers Navel also came to be known as Australians. In fact, any forms which differed from the true Bahia of the "Tibbet" tree type were very likely to be called Australians, and on account of this name they were supposed by many to have originated in Australia. 1 "Orange Culture in California," by T. A. Garey, San Fran- cisco, 1882. History and Development of the Citrus hidiistry 17 I can find no evidence whatever in support of the state- ment made by Lelong in 1888 that "The Australian Navel was introduced by Louis Wolfskill in 1874." The success- ful importation of the true Bahia took place as follows : In 1870 William Saunders, then in charge of the govern- ment propagating grounds at Washington, D, C, through the assistance of a lady missionary stationed at Bahia, Brazil, had twelve trees of the Bahia Navel orange propa- gated and sent to Washington in tubs. All twelve of these were true Bahia, and after being placed in the greenhouse at Washington were used indiscriminately as a source of buds from which were propagated a number of trees for distribution, many of which were later sent to Florida and California. All twelve of these original trees for some reason passed out of existence. The first lot propagated was distributed to California and Florida, and one tree from this lot was planted in the orange house at Washing- ton, where it still remains. The common idea that this tree in Washington is the original tree imported is wrong. It was propagated from one of the original twelve. The active settlement of Riverside, California, began about 1870, and was extensively advertised in the East by Judge North, the founder of the Colony. Among other settlers attracted were Luther C. Tibbet and wife. Early in 1873 Mrs. Tibbet (Fig.3) was in Washington just previous to starting to her new home at Riverside, California. While visiting the government propagating gardens, Mr. Saunders offered to give her some trees of this Bahia orange and she gladly accepted two trees, which she carried to California, where she and her husband planted them beside their cottage in Riverside on land which they had 18 Citrus Fruits horaesteaded. According to present street nomenclature the spot formerly occupied by the Tibbet cottage is on Central Avenue near Palm Avenue. The fruit from these trees first attracted attention at a private meeting of fruit growers in the winter of 1877-88, at which time the Navel trees sold by Thomas A. Garey had been in bearing several years. In February, 1879, the Southern Cali- fornia Horticultural Society (J. De Barth Shorb, President, and L.M.Holt, Secretary) held a citrus fair at Riverside. At this fair ISIr. T. D. Cover exhibited fruit from the Tibbet trees and was awarded first prize over other Navels exhibited from Orange County, which came from trees imported from Australia by Mr. Garey. The difl'erence between the two forms was recognized by ex- pert fruit grow^ers; the Tibbet oranges being called Washington Navels because Mrs. Tibbet, probably for- getting the name "Bahia," always said in answer to in- FiG. 3. — Mrs. L. C. Tibbet, who first brought the true Navel orange to Cali- fornia. History and Development of the Citrus Industry 19 quiries that the trees came from Washington. All other kinds of Navels were called Australians because it was supposed that they all came from Australia. A. S. White of Riverside writing in the Riverside Press and Ilorticulturist under date of June 26, 1880, says, — " It (Washington Navel) was first exhibited at the River- side Citrus Fair last year (1879), where it attracted great attention, its appearance being so unlike the other Navels on exhibition, which were from the stock imported into California from Australia. The marked points of differ- ence between the two Navel oranges lie in their external appearance. Instead of being like the Australian, ribbed lengthwise, it is smooth and more globular. The skin is of a finer texture, has more of a satin-like appearance, and shows a much higher color, being of a bronzy-gold tint." An editorial (presumably by L. M. Holt) in Riverside Press and Horticulturist, in 1883, says: "We have but two varieties as yet of the so-called Navel orange. The first was introduced into California from Australia. Both varieties, the Washington and Australian Navels, are now being grown quite extensively though the trees are young yet, and I must confess it is at times a puzzle to distinguish one from the other, under test conditions, and I believe I am not alone in this position." After studying a number of the discussions in the early literature, the writer is of the opinion that since both the true and false form of Bahia orange existed in Australia, that T. A. Garey's original importation in 1870 was mixed and that at least some trees sold by him were the true Bahia. How else can we account for the fact that cer- 20 Citrus Fruits tain reputable and apparently experienced men insisted for years that some of the trees sold by Garey bore fruit identical with that of the Tibbet trees at Riverside. If this is true, then the Tibbet trees were not the first genu- ine Bahia Navels to reach California. It is a fact beyond dispute, however, that the Tibbet trees are the ones which attracted attention and were undoubtedly the direct cause of the great boom in the orange growing business which began in the early 80's. Giving IVIrs. Tibbet two trees, Mr. Saunders sent several trees to Florida and some to California. Alexander Craw, then foreman for J. M. Asher, a nurseryman of San Diego, is said to have received two of these trees. It might be argued that jNIr. Garey secured his stock of Bahia from Craw or even from Mr. Saunders at Washington. This is barely possible, but in view of the shortness of time thus allowed to work up the stock, and the letters of his contemporaries stating the contrary, it is hardly probable. For two or three years after the Tibbet trees began to be propagated in Riverside this orange was known as the Washington Navel. In 1883, however, a determined effort by the people of Riverside was made to change the name to Riverside Navel in order (according to L. M. Holt in Ontario Fruit Grower, May 16, 1883) that Riverside, the town where this variety happened to be first tested, might get the benefit of the advertising which would follow the use of this name. O. H. Conger of Pasadena and others vigorously opposed this to such good purpose that the name Riverside Navel became a synonym. Luther C. Tibbet is known to have been rather improvi- History and Development of the Citrus Industry 21 dent. He never owned any orange trees other than the two his wife brought from Washington. He permitted his homestead to pass out of his hands, but he and his wife Fig. 4. — One of the original Washington Na\il to California. were allowed to live in the cottage during the life of Mrs. Tibbet. After her death Tibbet was cared for at the County Hospital until he died July 1, 1902. In 1903 Louis Jacobs was the owner of the Tibbet 22 Citrus Fruits homestead. He gave one of the trees to Frank A. Miller, proprietor of the Glenwood Hotel, who had it removed to its present location in front of the hotel May 7, 1903. President Roosevelt, a guest at the hotel at the time, assisted in transplanting this tree, for the care of which Mt. Miller is now responsible. Citrus Acreage ix Counties in California having more THAN 10,000 Trees in 1910 Los Angeles . . San Bernardino Tulare . . . Riverside . . . Orange . . . Ventura . . . San Diego . . Butte .... Santa Barbara . Fresno .... Kern .... Sacramento . . San Louis Obispo Placer .... Yolo .... Glenn .... Tehama . . . Sonoma Colusa .... Solano . . . All other counties Total for state Number of Trees 3,283,500 3,149,250 2,985,000 1,966,705 1,149,605 503,137 395,974 146,673 144,270 106,928 78,500 55,780 39,000 33,115 18,575 16,540 13,565 11,270 11,000 11,000 56,797 14,176,184 43,780 41,990 39,800 25,222 15,328 6,708 5,279 1,957 1,924 1,746 1,033 744 520 441 247 221 180 150 146 147 754 188,317 History and Development of the Citrus Industry 23 About the same time the other original tree was given to the city by Mr. Jacobs and it was transferred to a small plot of ground at the head of Magnolia Avenue. J. H. Reed, then tree warden of Riverside, placed a substantial ornamental iron fence around it which affords protection from any thoughtless or selfish person. The city of Riverside is responsible for the care of this tree. Both the original trees are at tliis date in a healthy and flourishing condition, and the one on INIagnoha Avenue especially is producing fair crops (Fig. 4). CITRUS GROWING IN ARIZONA AND SONORA The citrus industry of Arizona is hardly more than twenty-five years old, although occasional orange trees may have been planted at a very much earlier date. The first plantings of any importance were along the Arizona Canal west of Scottsdale in the Salt River Valley. The Ingleside orange grove on the foothills of Camel's Back Mountain was the largest of these early plantings, and it was due largely to its success that the acreage was in- creased in this locality. Another important prospective citrus area is on Yuma Heights near Yuma, where an old orchard ten or twelve acres in extent has served for many years to indicate the possibilities of this area. The lack of water develop- ment has been the chief hindrance to the planting of additional acreage. While California received its first orange seed from Sonora, this country has been very backward in its citrus development, chiefly for the reason that it has been ¥ 24^^ i^^ Citrus Fruits 24^ Ajsol^ed from home markets and liandieapped by the /^a^" in reaching American markets. ^7 Xjeograi)hically Sonora })eh)ngs to the Arizona and south- ^ Astern Cahfornia areas as the cHmate and soil con{htions 4X*are very similar. The chief commercial orchards are situated near Hermosillo, in the valley of the Sonora River, and near Guaymas. The production of fruit at Guaymas was greatly reduced in 1905 by a serious in- festation of the red scale. The variety chiefly grown at Hermosillo is the sweet seedling orange. The production gradually increased and in 1908 about 250 cars were sent in bond through the Ignited States to Canada, which they enter duty free. The oranges produced in southern Mexico, especially in the states of Jalisco, Morelos, and San Luis Potosi, where the climate is more tropical, differ in character from those grown in Sonora, being inferior for shipping. Much of southern IVIexico is infested with the Morelos orange maggot, Trypeta ludens, and this interferes with the marketing of the fruit. CHAPTER II CITRUS GEOGRAPHY AND CLIMATOLOGY OF CALIFORNIA Citrus fruits originated in India and the Malay Archi- pelago and are generally regarded as tropical fruits, yet it is a curious fact that the greatest commercial success with them has been obtained in semitropical countries. This statement applies especially to oranges and to a less extent to limes and pomelos. The bulk of the oranges which supply the markets of the world are produced in countries which experience a certain degree of frost, such as California, Spain, Florida, Palestine, Austraha, Japan, and Italy. Oranges grown in moist tropical coun- tries are lacking in tartness, color, shipping and keep- ing quahties. All of these qualities, so desirable in a marketable orange, become more marked as we approach the line where frequency of frosts makes the culture of the trees unprofitable. The citrus producing lands of California are scattered from San Diego to Shasta County, a north and south dis- tance of four hundred and fifty miles. It is a peculiar fact that there are orange orchards in California in the same latitude with New York City and Lincoln, Nebraska. This is made possible by the peculiar topography of the 25 26 Citni.'i Fruits state, whereby the mountain ranges are so situated that the cold winds of the north are shut out from interior valleys, and the full effects of the abundant winter sun- shine allowed to accumulate. Along the southern coast also the mild moisture laden breezes from the Pacific modify the climate of the country between the mountains and the sea without interference from northern blasts, which are diverted eastward by the mountain barrier in northern (\difornia. Yrom the point of view of the fruit grower, longitude is more important than latitude. Fig. 5 shows the distribution of the citrus areas of California. CLASSIFICATION OF CITRUS AREAS The areas where climatic conditions permit the growth of citrus trees may be roughly grouped into three divi- sions and designated as the Southern Coast, Interior Valleys, and Northern Coast Divisions, in the order of their importance as citrus producing areas. The Interior Valleys Division includes the Sacramento, San Joaquin, Upper Santa Ana, Coachella, Imperial, and Colorado Valleys and embraces all the country not imme- diately adjacent to or within the influence of the ocean. The Southern Coast Division includes all the citrus country between the mountains and the sea as far north as Santa Barbara. The Northern Coast Division includes all the country within the influence of the sea from Santa Maria as far north as northern Sonoma County. The amount of rainfall varies much in different parts of the state, but the rainy season is fairly uniform, being from November to March inclusive throughout each of these ^7/ >^'^f^- "^^^ S K, I V U POSSIBLE AREA PLANTED AREA Fig. 5. — Cilifoniia citrus areas. (27) 28 Citrus Fruits areas. Rainfall in the summer is very rare and thunder and lightning exceedingly rare especially near the coast. As the citrus industries of these three divisions differ in many particulars, we will discuss each division sepa- rately. The Southern Coast Division The climate of this section is characterized by an equa- ble temperature with cool summers and warm winters. Fig. 6. — Four-year-old Valencia orange grove in Los Angeles County. The rainfall is about 18 inches in the northern but de- creases in the southern part. The air is quite moist as compared with the interior, and there are frequent fogs and overcast skies. The prevailing breezes are from the Pacific Ocean, which has a surface temperature not far from 60° F. at all seasons of the year. The extent of the ocean influence depends upon local topography, being narrow in Santa Barbara County and widening out toward the south and including the San Gabriel Valley which contains the most highly developed and largest, Citrus Geography and Climatology of California 29 contiguous citrus area in the state. Fig. 6 shows a representative orange plantation in southern California. In general, the soils of this region are deep and very fertile, being heavier near the coast and lighter in charac- ter toward the interior. The two prevailing soil types are the Placentia series, resulting from the weathering of reddish granite, which outcrops at many places, and the Maricopa series, which are alluvial in nature, being an ancient flood plain. These latter soils are darker in color and often contain smooth cobbles and bowdders invariable amounts. Less important soil types are the black adobe sometimes found on the foothills and the light sandy soils of the river bottoms. While the prevailing breezes are westerly, this section of country is occasionally visited by characteristic hot northers which blow with force for several days at a time from the northeast. At such times the air becomes excessively dry and high temperatures prevail. Such desiccating winds are sometimes quite injurious to vege- tation and cause a severe loss of water from plants and soil. It is fortunate that such winds are not of more frequent occurrence. The southern coast is especially adapted to the growing of lemons, which here produce a larger proportion of high- priced summer fruit. Stored lemons also keep better and expensive storehouses are not needed as is the case in interior valleys. The cool summers also make it possible to hold Valencia oranges on the trees until the follow- ing October and November, when very high prices are often realized. This section of country is also well suited to the production of nursery stock, which is grown in very 30 Citrus Fruits large quantities, the San Gabriel Valley being the center of this industry. The Washington Navel orange here produces very heavy crops, but the fruit ripens later and is somewhat inferior to that produced in interior valleys both as re- gards color, texture, flavor, and shipping qualities. The Interior Valley Division The climate of all the interior valleys is characterized by conditions more or less extreme. The air is nearly always dry and this permits rapid radiation, causing a wide range in temperature each day. Rainfall is fairly abundant in winter in the northern valleys and less so tovv'ard the south. The air is free from fogs and dew in summer and constant sunshine is the rule. The days are often very hot, while the nights are always cool. The floors of the valleys are, as a rule, frosty in winter and on this account the principal citrus areas are found along the foothiUs, above the frost line, and where irriga- tion water is available. Such areas are usually at an eleva- tion of from 500 to 1500 feet above the sea, and from 100 to 500 feet above the floor or "draw" of the valley. In such locations a few feet in the perpendicular is of far greater importance to the citrus grower than many miles in the horizontal. That is to say, whether the orchard is planted in a "draw" or on a bluff above it, yet on the same ranch, may mean more for the success or failure of the grove than whether the trees are planted near Holt- ville or at Oroville five hundred and fifty miles distant. Cold air is heavy and on quiet nights flows down and col- Citrus Geography and Climatology of California 31 lects in the lowlands, leaving the foothills above the frost line. In the central valleys oranges ripen very early and as some of these are far to the north of the Coast Coun- try, the unusual procedure of shipping earliest ripening fruits southward to market is accounted for. The largest producing district in this division lies on the eastern foothills of Tulare County, including Woodlake and Porterville, at an elevation of four or five hundred feet above sea-level. One of the typical soils of this district is known as the Porterville clay loam adobe, which is a residual soil characteristic of the higher foothill slopes. Lower down the valley slopes are found soils of the San Joaquin series, which are sometimes characterized by "hog-wallows" and a certain amount of hardpan. The valley floor is composed mostly of alluvial soils of the Hanford series. In the northern Sacramento Valley the soils are very variable, but are mostly of a reddish color. They are in large part sedimentary soils of the San Joaquin, Stockton, Alamo, and other series. While there are many exceptions, it is true that these soils, especially on the east side of the valley, are quite generally underlaid by a stratum of dense, impervious hardpan which occurs at variable depths. Where hardpan is near the surface, the land is not suited to citrus fruits unless it be dynamited and the hardpan thoroughly broken up. The Northern Coast Division In outline this division is very irregular, consisting in places of a narrow strip between the mountains and the 32 Citrus' Fruits sea and extending occasionally into valleys where the hills are low and do not entirely shut ofl" the cool, moist sea- breezes. East of the bay region the coast influences extend far inland, following the Sacramento River and tempering the climatic conditions at the junction of the San Joaquin and Sacramento Valleys to such an extent that the region between the cities of Stockton and Sacra- mento is really intermediate in climatic characteristics. The climate of the Northern Coast forms a strong con- trast with that of the interior valleys. It is comparatively free from extremes of temperature, being warm in winter and cool in summer. The w^inter rainfall is usually heavy and there is much fog in summer. Here green, grass- covered hills are the rule instead of the bare rocky buttes of the interior. There are no large commercial citrus areas within this district, yet oranges and lemons are grown in yards and gardens and the product is used for local consumption throughout the district. The total amount of summer heat is small, and oranges do not yield well as a rule nor is the fruit high in sugar content. The color also is poor on account of the lack of abundant sunshine, and the trees are subject to the ravages of many insect pests and fungous diseases which are not able to survive the hot summers of the interior valleys. The trunks and branches of trees on the coast are apt to become covered with a growth of lichens and alga? which should be removed with alkali sprays. The soils of the coast country are chiefly deep rich residual soils formed by the gradual weathering and breaking down of the local rock masses. Citriis Geography and Clinuitologij of California 33 THE FROST HAZARD It has been asserted that certain districts in Cahfornia are free from frost. This is hardly true, for a certain frost hazard exists in all districts both north and south. Almost all districts on the other hand embrace certain areas which are comparatively frost free. One thing which usually impresses the stranger from the East most forcibly is the sharpness with which the frost lines are drawn. There are many ranches of a hundred acres or less which are divided by these frost lines into citrus lands, walnut lands, and alfalfa lands. It is often very difficult to accurately judge the frost hazard on any given piece of land unless there be an old orchard alongside upon the history of which, together with the local topog- raphy, an estimate may be based. Failures due directly to faulty judgment in regard to the frost hazard are almost without number. In recent years the science of orchard heating as de- scribed in Chapter XIV has enabled growers to insure their crops against occasional frosts, but where orchards must be heated many nights each winter the expense is quite likely to interfere with the profits. We may conclude then that throughout the citrus divi- sions of the Southwest there are specially favored dis- tricts where citrus fruits grow to perfection and are seldom injured by cold. Within each of these districts, however, there are many localities of irregular outline and extent which on account of local topography are quite out of the question as citrus lands. On this point Lelong ^ writes as follows : 1 "Culture of the Citrus in California," 1902. D 34 Citrus Fruits "Wherever cold currents of air from high altitudes flow to the valley without interruption, it will not be safe to attemi)t citrus culture at any elevation within the sweep of these currents. On the other hand, wherever the descending currents are cut off or turned aside by spurs of the mountains, leaving the warm atmosphere of the days undisturbed during the nights, there orange and lemon culture may be engaged in with little danger from frost. In other words, the eddies of air currents must be selected and the main flow of these currents must be avoided. " Everybody who has traveled along the Sierra foothills, parallel with the valleys, particularly in the winter season and at night, will recall his surprise at the sudden changes of the temperature of the atmosphere within short dis- tances. He may also remember to have noticed tender plants and shrubs seared and frost-bitten, while just over a ridge or cone the same plants and shrubs were in full leaf and growing luxuriantly. Want of attention to these facts has caused many a disastrous failure in the culti- vation of citrus fruits in California." ATMOSPHERIC HUMIDITY In the interior valleys which are fanned by dry desert breezes, the amount of atmospheric moisture is very low, and this together with the great heat tends to produce oranges of high sugar content and with very desirable deep red color. Dry air also discourages the growth of certain diseases affecting the tree, as well as certain scale insects, lichens, and algae which cannot endure the Citrus Geography and Climatology of California 35 desert conditions. On the other hand, lemon trees under such climatic conditions tend to bear only one crop a year, and the proper curing and keeping of lemons is made more difficult. The moist and foggy coast country with its cool sea breezes brings about a somewhat different phase of the industry. Here lemons tend to bear a con- ^^^^^^H|^H ^pp-.r H^^UHBBBMMim^P^ ^^ Fig. 7. •Typical scene in Los Angeles C'ouiity. robusta on right. Windbreak of (ii tinuous crop the year round, and the fruit may be easily stored in open sheds and kept in good condition for six or eight months. Oranges near the coast are six or eight weeks later in ripening than those of the interior, and the trees are subject to a larger number of the insect pests and diseases to which the citrus tree is heir. 36 Citni.i Fruits WINDS Stn)iig winds are a serious hindrance to the citrus grower. The young foHage is badly torn or may even be Nfc^u, Fic;. S. — Pinus radiata, ii iiiitivf |)iiu' used ;i.s ;i winclhiciik. blown from the trees ; the fruit is bruised, scarred, and covered with unsightly callous marks ; the trees are pre- vented from forming symmetrical heads ; and in some cases the soil itself is either blown away from the roots Citrus Geography and Cliniatologt/ of California 37 or banked too deep around the trunks of the trees. In some extreme cases, the traveling sand wears away the bark of young trees near the ground. As a rule, windy locations should be avoided in selecting a site for a citrus Fi(i. 9. — Orange tree denuded of foliage on windward -sido by three days of desert wind. orchard. In some cases, however, where all the other conditions are right, the force of the wind may be broken by growing windbreaks of cypress, eucalyptus, or cedar. Care should be exercised that the windbreak is not allowed to grow too thick and become a "wind-stop," 38 Citrii.'i Fruits as this may interfere with atmospheric drainage and make a frost pocket of the grove. A Hve windbreak is ob- jectionable on the ground that the roots approj)riate the plant food and water from one or two rows on either side and seriously interfere with the fruiting of the orchard trees. This trouble may be obviated to some extent by digging a trench ten feet from the windbreak and three feet deep every second year and cutting all the feeding roots. Care should be used in selecting varieties of trees for windbreaks that they may not be host plants for insects which affect citrus trees. The pepper tree, Schijius molle, for example, makes an excellent wind- break and is largely used in interior valleys where the black scale is of less importance. Near the coast such trees may have to be fumigated occasionally at great expense. Figs. 7 and 8 show windbreaks of the silk oak (GreviUea robusta) and Monterey pine {Pinus radiata), which are much used in parts of California. Fig. 9 il- lustrates the damaging effect of the wind. SUNLIGHT While a certain amount of sunlight is absolutely neces- sary for plant growth, there are places in California where citrus plants are over-illuminated. Sunburn of the fruit and tree trunks and even of the leaves often occurs in the dry interior valleys, where the lack of moisture in the air permits the actinic rays of the sun to strike the trees with full force. In such situations, the fruit borne on the outside of the trees and fully exposed to the light is inferior and often ruined, while the fruit which is Citrus (ieography and Climatology of California 39 screened by foliage may be of the very finest quality. It is the custom among nurserymen to shield citrus seedlings from the light by growing them, for the first six or eight months, under lath screens so arranged as to reduce the total light about 75 per cent. Running the lath north and south will provide alternating light and shadow for any given seedhng as the sun moves from east to west. CHAPTER III CITRUS BOTANY, GROSS STRUCTURE, AND HABITS OF GROWTH Citrus fruits differ from olives, figs, dates, and pome- granates in being of comparatively modern origin. They emerged from the wild state in the Malay Archipelago and southern Asia. Certainly citrus fruits were not known by civilized peoples until comparatively recent times. The ancient Egyptians did not know the citrus fruits. The Romans did not know the orange or any other edible form except perhaps the citron at the be- ginning of the Christian Era.^ While the Old Testament makes frequent mention of olives, pomegranates, figs, and other fruits, no mention is made of any citrus fruit unless we except the word "hadar" translated "goodly trees" (Leviticus 23 : 40) as referring to the citron. Risso,^ one of the most able of the early writers on citrus, compared the ancient texts and claims that this word merely refers to any beautiful or fine tree. It is likely that the Hebrews became acquainted with this fruit at the time of the Babylonish captivity. Be this as it may, the Jews believe this word refers to the citron, or etrog as 1 De Candolle, "Origin of Cultivated Plants," p. 181. ^ Risso and Poiteau, "Histoire Naturelle des Grangers." 40 Citrus Botany, Gross Structure, and Habits of (trowth 41 it is called by them, and to this day they present them- selves at the synagogue on the day of the Feast of Tabernacles, as commanded in Leviticus, with a citron in their hands together with an unopened date palm leaf, a three-parted branch of myrtle, and a willow twig. The citron, known by the Romans as Malum persicum, the apple of the Persians, was transplanted to Italy about the third or fourth century. The lemon was not brought to southern Europe until after the tenth century, and the earliest Italian reference to it is dated 1250 a.d. The bitter or sour orange was unknown to the early Greeks and Romans. It probably originated ,in eastern India and spread westward slowdy. When it reached Mesopotamia it received the Sanskrit name nagarunga, which was changed to verunga and arangi. In medieval Latin it became arancium and RnixWy aurantium, the present Latin name from which our English word orange is de- rived. The Crusaders saw the bitter orange in Palestine. It was taken by the Arabs to Sicily in 1002, spread from there to Spain, from whence it was taken to Florida soon after the settlement of that Colony. In Florida the bitter or sour orange ran wild, and dense thickets exist there to-day which yield the greater part of the sour orange seeds planted by California nurserymen. It is most remarkable that so good a fruit as the sweet orange should not have been known to ancient writers, yet they make no mention of it. In fact the sweet orange was not introduced into Europe until the beginning of the fifteenth century, when the Portuguese brought im- proved forms of it from south China. A number of writers 42 Citrus Fruits speak of the sweet orange as cultivated in Spain in the sixteenth century. At a very early date the Portuguese carried the orange to Brazil, where it ran wild as it did in Florida. From Brazil the orange spread southward into Paraguay, part of Uruguay, and northern Argentina where large areas are now covered with a natural growth of wild sweet orange trees. CLASSIFICATION The genus Citrus belongs to the family Rutaceop and rep- resents the highest development within the family. There are no species of citrus native to either North or South America. A relative is the prickly ash or " toothache tree," Xanthoxylum americanum, of the southeastern United States. No two systematic botanists appear to be agreed as to the proper classification of the many different species. This is probably due to the fact that several of the species hybridize readily and it is very difficult to determine which of the forms are of hybrid origin. The writer makes no pretense to having solved this perplexing problem by independent botanical research. He has simply studied the different schemes proposed and from them arranged a practicable, working classification for the use of students, fruit-growers, and others who desire a simple bird's-eye view of the ten species in which they are chiefly interested. Persons particularly interested in citrus botany are referred to Hume, " Citrus Fruits and their Culture " ; to Bonavia, " Oranges and Lemons of India " ; and to Swingle, "Citrus" in "Bailey's Standard Cyclopedia of American Horticulture." Citrus Botany, Gross Structure, and Habits of Growth 43 Citrus (rifoliata bergamia, sinensis, Aurantium, nohilis decumana, japonica, Medica, Limonia, the deciduous orange {Poncirus tri- foliata). Bergamot orange. common sweet orange. sour stock, Seville, or bitter orange. [ the King orange. I Far. deliciosa — the Mandarin or kid- I glove orange. Tangerine. [ Var. unshiu — the Satsuma orange. the pomelo (grapefruit), shaddock. kumquats. citron of commerce. sour lemon, sweet lemon. aurantifolia, sour lime, sweet lime. All of these ten species are now grown, to some extent at least, in California, although some of course are very much more important than others. Citrus trifoliata. — This is the only deciduous orange. The fruit is not edible. It is highly ornamental and very hardy to cold, being used in yard and garden plantings and for hedges as far north as Washington, D. C. It is used to a certain extent in Florida and more generally in Texas as a stock upon which to bud edible oranges. Its use as a stock in California was never widespread, and is now almost obso- lete. Citrus trifoliata has recently been used to a considerable extent in breeding work, the object being to combine the cold resisting qualities of the trifoliata with the good qualities of the more tender species which bear edible fruit. It is native to Japan and China and was introduced into Europe more than one hundred years ago. This species is now by some put in the genus Poncirus, becoming P. trifoliata. Citrus bergamia. — The Bergamot orange from which the oil of bergamot is made is grown commercially in Europe. In California it is grown only as an occasional specimen or as a hedge plant in gardens. 44 Citrus Fruits Citrus sinensis. — The ordinary sweet oranges including such varieties as Washington Navel, Valencia, Mediterra- nean Sweet, Ruby Blood, and a long list of others. Citrus Aurautium. — This is the sour or bitter bigarade orange, the fresh fruit of which is hardly edilile, but which is coming to be used more and more in the flavoring of marma- lades and various other by-products. Seedlings of this orange have almost entirely superseded others as a stock upon which to grow all kinds of citrus fruits in California. The reason for this is its superior resistance to gum-disease and foot-rot. The seed from which this "sour stock" is grown comes chiefly from the wild thickets in Florida. In Europe this form is often called the Se\'ille orange. Citrus nohilis. — The description of this species was l)ased on a form very like the King orange. It includes the var. ddiciosa, the ordinary Mandarin oranges such as the Tan- gerine and the var. unshiu, which is the Satsuma orange. Citrus dccumana. — Here are included the pomelos, often incorrectly called "grapefruit,"^ and the shaddock. They are vigorous grownng trees with very dark green leaves, very prolific in bearing. The pomelo is growing rapidly in public esteem, but the shaddock is inedible. The shaddock is the largest of all the citrus fruits, but has an extremely thick skin and bitter juice. It is the only citrus which has hairs or pubescence on the young twigs and imder sides of the leaves, and is grown only for ornament or curiosity. Citrus japonica (recently referred to the genus Fortunella). — The Kumquats, Kin-Kans, or golden oranges, small bushy plants from Cochin-China. The fruits are small, with mostly acid pulp and sweet aromatic rinds, for preserving and for decorations. ^ The term "grapefruit" has, chiefly through the influence of " the trade," become adopted by common usage, and it is hardly worth while now to insist on th(> xiso of the more correct term. Citrm Botany, Gross Structure, and Habits of Growth 45 Citrus Mcdica. — The citron from wliich the candied citron sold by grocers is made. The form known in CaH- fornia as the Chinese lemon and much used in the early days as a stock is thought to belong here. Citrus Limonin. — The lemons including both the sour lemons and the sweet lemons. Citrus aurantifolia. — The limes including both the sour Mexican and Rangpur limes and the sweet limes which latter are considered to be of hybrid origin. THE CITRUS PLANT The Root Citrus trees differ from many plants in having no root- hairs whatever upon the fibrous, feeding roots. The feeding roots are comparatively large, very abundant, and grow very rapidly. Those sheared off each year by the plow in turning under a cover crop are quickly replaced. In shallow soils, however, where most of the fibrous roots are near the surface, it is unwise to be too reckless with the large turning plow. Under arid conditions the feeding roots are not confined to the surface layer of soil, but where there is no layer of hardpan to interfere they dis- tribute themselves throughout the soil usually between the eighth and thirty-sixth inch levels. In very deep, well aerated soils they may forage much deeper. The large main roots serve in a double capacity; as braces to hold the tree upright against the wind, and as conveyors of water and food between the fibrous feeders and the trunk. Large perpendicular roots known as tap-roots are not essential to the health or w^ell-being of the trees and are invariably cut when the young nursery 46 Citrus Fruits trees are dug for transplanting. Subsequently the sweet orange root will devote itself mainly to sending out laterals, while the sour orange will usually send down two or three strong tap-roots in the place of the one w^hich w^as cut. The pomelo shows much variation in regard to the formation of tap-roots. Wood Structure and Grouih Citrus wood is very closely knit in structure, being hard, strong, and tough. It is light in color, with very fine grain and with no apparent heart wood ; that is, there is no difference in color between heart wood and sap wood. The rings observable in a cross section are close together and are of no value in determining the age of the citrus tree, as they are in the case of pine or oak trees. This is on account of the fact that the citrus tree forms several rings each year according to the number of vegetative growths. The citrus tree does not grow at a uniform rate during the season, but makes three or more growths of new twigs and leaves each year, with corresponding rest periods. The heaviest growth is in the spring just before blooming, the flowers being borne on the new shoots. Another smaller and more irregular growth is made in mid-summer, and a third in the late fall. The number of growths made and the times they occur vary with the local weather con- ditions and the method of irrigation. The main framework branches of old lemon trees often present a curious flattened shape next the trunk. The greatest diameter is perpendicular, but the width of the rings is much thicker on the lower than the upper side, the Citrus Botany, Gross Structure, atid Habits of Growth 47 center of growth being crowded close to the bark on the upper side. This curious condition is entirely normal in the lemon and greatly strengthens the branches, enabling them to carry a much larger load without breaking. There are two sap currents in the trunk and branches, one consisting of dissolved mineral matters taken from the soil water by the roots, which passes up through vessels in the wood to the leaves ; and an- other, consisting of elaborated plant food, and other complex substances, which passes down through the inner bark and nourishes every growing part, even the tips of the longest roots. It should be remembered that the action between root and leaf is reciprocal. The most remote tip of the longest root must await the return of the elaborated sap from the leaves before it is able to grow a fraction of an inch. For sake of emphasis we repeat : the roots of a plant are quite as de- pendent upon the leaves for elaborated food as they are upon the soil for raw food, for roots cannot use raw mineral food. That the downward current of elaborated sap takes place through the bark is proved by the swelling which occurs just above the point of constriction when a label wire is overlooked and allowed to remain, on a young tree. Fig. 10. — Growth rings in a flattened brace limb of lemon. 4,S Citrus Frtiif.'i Advantage is taken of this fact in the l)r()cess known as "ringing" which is chiefly used with grapes and pears. A ring of bark half an inch wide is removed from the small branch which bears a fruit cluster. The fruit and leaves continue to draw food from the roots through the wood, but as the l)ranch is prevented from returning its pro- portionate share of elaborated food to the trunk and roots, it soon accumulates an extra amount which causes the fruit to grow to an unusually large size. By this method aNavelorange Fig. 11. - Result of exix'rinicnt wlii.h .shows ^^^'^f produCcd which that a girdled orange tree may grow new weighed 3 j poUnds bark if treated in time. A, untreated; i iio- i js, treated. and measured 18 inclies in circumference.^ ^Scientific American, Dec. 14, 1912, p. 515. Citrus Botany, Gross Structure, and Habits of Growth 49 The line which separates the two currents of sap is known as the cambium and is roughly represented by the line of cleavage when a strip of bark is pulled away from the trunk. It is on this line that growth takes place, the cells dividing continually, one part going to build wood and the other causing a thickening of the bark. Citrus trees are apt to form large quantities of giun along the line of the cambium, when stimulated by the growth of fungous parasites, or by other causes, the exact nature of which are not clearly understood. Many trees are unable to grow new bark direct from the cambium, but heal over wounds by pushing new tissue out from the sides of the wounds. The citrus tree will often grow new bark direct from cambium laid bare by gophers or gum-disease. Occasionally a tree which has been entirely girdled will grow new bark and recover. The bark of citrus trees is also peculiar in that it retains some green matter or chlorophyll and continues to function as a leaf until the tree reaches a great age. Leaves With the exception of Citrus trifoliata, all citrus trees are evergreen ; that is, the bulk of the leaves do not fall before the new leaves have expanded. A few of the oldest leaves may fall at any time of the year, but the })eriod of heaviest fall is in April and May after the spring growth has taken place. The normal life of an orange leaf depends on the kind of wood upon which it is borne. Leaves on the fine fruiting brush usually remain on the tree for about fifteen months, while leaves on vigorous upright vegeta- 50 Citrus Fruits tive growths will remain green and in flourishing condi- tion for three and even four years. The leaves on the trunks of nursery trees, if protected and not removed, will usually remain for several years. It is customary to re- move these leaves at the time the tree is dug for the purpose of reducing transpiration. In the case of the trifoliate orange the leaves fall in the autumn, the tree remaining bare during winter and until after the blooming period in spring. Citrus leaves vary in shape and size with the different species ; the pomelo and Seville orange having broad wings on the petioles, while the sweet orange has a very narrow wing and the citron none at all. The width of these wings will vary a good deal, being wider on the vigorous shoots and very much smaller on the fruiting brush. The edges of the sweet orange leaf are entire, while with the lemon and lime the edges are indented or crenate. Most, if not all, of the stomata or breathing pores are situated on the under side of the leaves, and this is a distinct advantage when the upper surfaces of the leaves become coated with dust from the roads during the dry season, or with cement dust from near-by cement mills. One striking characteristic of all citrus leaves is the pres- ence of numerous glands, w^hich maybe easily seen with the unaided eye, although they do not project above the sur- face of the leaf. These glands are filled with a fragrant and aromatic oil which is very volatile and gives to the freshly crushed leaves their characteristic odor. This odor varies with the different species. One method of distin- guishing between sweet and sour stock seedlings in the nursery is by recognizing the odor of the crushed leaves. Citrus Botany, Gross Structure, and Habits of Growth 51 Thorns Sharp, slender thorns are characteristic of most kinds of citrus trees. Seedhngs of the sweet orange have per- haps the most formidable thorns and these are a serious hindrance in harvesting the fruit and pruning the trees. The trifoliate orange has short, thick thorns which are very numerous. Certain cultivated varieties are practically free from thorns, and this quality adds much to their popularity. Thorns are borne in the axils of the leaves, and their size, in a given variety, depends largely upon the vigor of the shoot upon which they occur, being long on rapidly growing shoots and short and inconspicuous on the fruiting brush. The Navel orange and Eureka lemon are practically thornless varieties ; yet on water-sprouts long sharp thorns may sometimes appear. Thorns are objectionable not only on account of the difficulty occasioned in picking fruit, but also on account of the injury done to the fruit itself. When the wind tosses the branches about, the fruit is stabbed on many sides by the thorns, giving an excellent opportunity for inoculation and consequent fungous decay. In dry weather when small wounds are quickly dried (and perhaps, to a certain extent, cauterized by the escape of oil from the broken oil- cells) there is less decay of fruit on the trees from this cause. While this is true, the constant rubbing or pricking of a fruit against the point of a thorn will so irritate the rind as to cause a very ugly callous to form on the skin and thus ruin the market value of the fruit. There is a widespread belief among citrus nurserymen and others that thorns may be largely eliminated from any 52 Citrus Fruits variety by careful selection of budwood through several bud generations. We know of no published data of scien- tific experiments to determine this point and doubt very much whether the grounds for this belief are sufficient. It can do no possible harm to select only thornless bud- wood for propagation, and where this happens to result in the separation of pure-line mutants which vary in thorni- ness much good may be done. On the other hand it is difficult to concei\e of how progress can be made by selec- tion within the pure-line. Flowers Citrus flowers are large, showy, and fragrant, and are borne in great profusion. They are mostly waxy white, although in the lemon and citron the backs of the petals are tinged with purple. The flowers are mostly perfect or complete, consisting of a green calyx with three to five lobes, subtending white petals, four to eight in number, which are thick, fleshy, and covered with oil glands. The stamens are numerous, twenty to sixty in number, their filaments (stalks) being more or less united. The style and stigma are large and conspicuous. The exudation of white mucilage by the stigma is quite copious, as is also the watery nectar in the base of the flower cup. The pollen is golden yellow and is produced in abundance except in certain varieties. The orange has flowers borne in cymes on shoots of the current year's growth. In the case of the lemon, kumquat, and others, the new growths are sometimes so short (the leaves appearing as mere bracts), that the flowers have the appearance of being borne on old wood. Fic. 112. — Valencia Drange blossoms. 54 Citrus Fruits The flowers of the orange and pomelo appear during April and early May. Occasionally a bunch here and there or even an entire tree may bloom at some other season, but the fruits from such off-season blooms will usually be ab- normal in shape and inferior in quality. Lemons bloom and set fruit the year round with the period of most abun- dant bloom coinciding with that of the orange. Lemon trees are peculiar in that they bear flowers of several kinds. Those that produce fruit are perfect, con- ^^M Fig. 13. Lemon blossoms showing perfect, partly aborted, and aborted pistils. taining both stamens and pistils. There are other flowers borne by the same tree in which the pistils are reduced to a mere rudiment while the stamens are large and well de- veloped. Li addition to these there are certain abortive buds, observed on the Eureka lemon chiefly, in which the petals do not develop but remain closed, the stigma forcing its way out between them. Only the perfect lemon blos- soms set fruit, although the second kind mentioned may aid in pollination. Lemons require about nine months from blossom to maturity of fruit. A few fruits will come Citrus Botany, Gross Structure, and Habits of Growth 55 up to size in six months, while some will remain undersized for a year and finally turn yellow, at which time they are picked regardless of size. Pollination The larger number of fruits, such as apples, plums, grapes, and strawberries, require pollination in order to set fruit. Some kinds of citrus fruits require pollination in order to set and mature fruit, but a large number do not. Many forms of citrus bear parthenocarpic or seedless fruits, and with these pollination is not only unneces- sary, but is apparently a disadvantage, inasmuch as it results in some cases in the formation of seeds which are objectionable. In Florida a large number of varieties are grown com- mercially, and as most of them contain seeds it is probable that a large proportion at least require pollination for their best development. Florida writers are strangely silent on this point. In the citrus districts of the Southwest it hap- pens that the five varieties chiefly grown — Washington Navel and Valencia oranges. Eureka and Lisbon lemons, and Marsh pomelo — - are more or less parthenocarpic. Those kinds which contain some seeds, as the Lisbon lemon for instance, are able to set and mature fruit without polli- nation, which results merely in the formation of seeds.^ The Washington Navel orange flowers contain no pollen whatever and in the p]ureka lemon viable pollen is rare except at certain seasons, yet these varieties produce quite ^ Unpublished Report on Pollination Experiments by the Writer. 56 Citrus Fruits as well when planted in solid blocks of hundreds of acres far from other varieties, as they do in mixed plantings. T. Ikeda ^ in a series of brilliant experiments has shed much light on this interesting subject. His })rincipal results may be summarized as follows : 1. Certain varieties of oranges reciuire pollination in order to set fruit. 2. Certain varieties of oranges which ordinarily contain seeds will without pollination set and mature a small num- ber of parthenocarpic fruits. 3. Many varieties of oranges are uncongenial, cross- pollination being followed by dropping of flow-ers and young fruit. 4. Cross-pollination between seed bearing and parthe- nocarpic varieties may result in the setting and maturing of fruit containing viable seeds, provided the pollen used is that of a congenial variety. 5. Parthenocarpic varieties do not require the stimulus of. pollination in order to set and mature fruit. 6. The pollen-tube may reach the ovule as soon as 30 hours after pollination. Fusion of male and female cells may begin 48 hours after pollination. Fertilization is completed in from 48 to 72 hours after pollination. 7. In the Washington Navel and Satsuma oranges the embryo-sacs usually disintegrate instead of developing into embryos capable of being fertilized. Occasionally a few normal embryo-sacs are produced in both Washington Navel and Satsuma oranges.^ Thus 1 Tomochika Ikeda, "On the Parthenocarpy of Citrus Fruits," Jour. Sci. Agr. Soc. Tokyo, Vol. 63, 1904. ^ The factors which influence the frequency of occurrence of Citrus Botany, Gross Structure, and Habits of Growth 57 a few seeds may be prochicefl provided the particular fruits having the normal embryo-sacs happen to be pollinated with viable pollen from congenial varieties. It is the remoteness of the chance of this occurring under ordinary field conditions that accounts for the comparative seedless- ness of these fruits. Apparently there is nothing in the Fig. 14 Orange flower X 2 /;, pi'^til , a, stigma ; c, style s, stamen; b, anther; c. filament, d, riectai> ovary; a, sepal; /, petal. structure of the blossoms of either the Washington Xavel or the Satsuma orange which would interfere in any way normal embryo-saes have not been fully worked out. Experi- ments now being carried on by the writer seem to indicate that the climate factor is most important. Normal embryo-sacs of Washington Navels occur much more frequently at Riverside than at Whittier where they are very rare. For this reason plant- breeders wishing to use the Navel as a maternal parent in cross- breeding work may e.xpect greater results from crosses made at Riverside or other interior points. 58 Citrus Fruits with the germination of pollen or normal extension of the pollen tube. The occasional seeds sometimes found in Washington Navel oranges as they occur on the market are undoubt- edly due to cross-pollination with some other variety by insects or other agencies. The question as to what would be the result should these seeds be planted and reared to maturity has already been answered by the experiment of W. H. Backus of Riverside, a part of whose report is here quoted.^ "Some years ago when almost every one was budding over their seedlings to Navels, I thought the result might be too many early oranges. At that time I did not think the Valencia the most desirable late orange, as a Cali- fornia orange should have high color in addition to being late. "To obtain this desirable feature, together with high color quality and medium size, I tried hybridizing the Mediterranean Sweet on the Washington Navel, three successive seasons, cutting all the oranges when ripe for seed. Altogether I secured about fourteen hundred seeds that were well matured. " These were planted in the seed bed, but owing to my lack of experience in nursery work, a large percentage of the little trees, of the first and second plantings, died when about three inches high. One peculiar thing to me was that over 90 per cent of the seeds sprouted from two to six shoots each.^ "The young nursery stock was much neglected for three 1 Riverside Daily Press, March 2, 1909. 2 An interesting record of polyembryony. Citm.s Botany, Gross Structure, ami Habits of Growth 59 or four years, when I took buds from the most thrifty to bud over old trees. Although these buds stand 10 to 18 feet apart in an old grove, still they made a rapid growth, equal to a straight seedling, and are now about 25 feet high. "The disappointment came when they began to bear. Many were of no value at all ; the best w^ere early, some apparently earlier in ripening than the Navel, but generally of good color, sweet and seedless. The trees were exceed- ingly thorny and some much more thrifty than others; many appeared to be good bearers while others were shy or very late in coming into bearing. Consequently al- most all have been rebudded or dug up." Polyemhryony A peculiar thing about citrus seeds is the fact that a variable proportion of them will give rise to from one to ten distinct seedlings each. This is known as polyem- brj'ony and is due to a number of adventitious embryos appearing in the embryo-sac. Some of these bud embryos may develop into seedling plants along with the sexual embryo which requires fertilization in order to develop. This explains why seedlings in the seed bed often appear to grow in bunches even though the seeds were planted sepa- rately. As only one of the seedlings arising from any given seed is the result of pollination and fertilization, it follows that the others must be vegetative seedlings, and, in case the seed is from a known variety, will reproduce the variety true from seed without the necessity of bud- ding. It is impossible, however, to distinguish the sexual 60 Citrus Fruits seedling from the others in the early years of growth, except in the case of crosses between forms which have very differently shaped leaves. It would be imprac- ticable to propagate Navels true from seed on account of the rarity of seeds and the necessity of pollinating the flowers, but it would be a simi)le matter with seed}^ varieties were it not for the difficultv above mentioned. Structure of the Fruit According to Bonavia,^ the citrus fruit consists mor- phologically of two whorls of transformed leaves, one going to make the rind and the other to make the group of carpels or sections of the fruit. Each carpel is supposed to be a leaf folded over in such a way that its two edges meet in the center on the axis of the fruit and along which the seeds are borne. The number of these sections or divisions varies considerably even in the same variety. The little juice sacks or vesicles within each carpel are supposed to be transformed oil glands of the leaves. As ^ E. Bonavia, "Oranges and Lemons of India," Vol. I. Fig. 15. — Polyembryony. Two orange seedlings from one seed. Citnt.'i Botany, (Iro.s.s Structure, and Ilabit.s of (Growth 01 varieties of double flowers are formed by the growth of an additional whorl of petals, so varieties of double fruits may come about l)y the growth of additional whorls of carpels, and this is what has taken place in the case of the Navel orange, as any one may obser\e by making a num- ber of thin transverse sections through the apical end of a Navel orange, and studying these sections. The vesicles in citrus fruits are multicellular and are attached by a stalk in nearly all cases to the outer wall of the carpel, only a very few being attached to the sides. These vesi- cles are fed directly by fibro-vascular bundles branching from the stem and running through the white spongy tissue which composes the inner part of the rind. The seeds vary in number from none as in the Navel to fifty or more in the trifoliata. They are attached to the inner edges of the carpels. Citrus fruits in common with other fruits are not to be considered as so much dead matter after they are plucked from the tree. They live and breathe (transpire) for many months. They also lose water and shrink in size and weight as a result of giving oft' carbon dioxide and water vapor. If protected from infection by decay-producing organisms, oranges or lemons will keep one year or more, when kept moist and cool, but ^^'ill eventually die and collapse from enzymatic fermentation. If they are al- lowed to lose moisture, they will dry up into balls as hard as wood. An understanding of the vital processes going on in citrus fruits is highly important in connection with the curing of lemons and pomelos. (See Chapter XVI.) Chemistry of the Fruit. — Citrus fruits from the same tree may vary much in their composition. Commercial Cali- 62 Citrus FruiU' Analyses of California Oranges and Lemons (From Bull. No. 93, Univ. Cal. Agr. Exp. Station) A. Proximate Analyses Wash. Med. Paper Malta Eureka Name op Variety Navel Sweet Rind Blood Lemon Average weight in grams 300 202 138 177 104 Water, per cent . . . 85.82 85.19 84.76 85.68 83.82 Organic matter, per cent 13.95 14.32 14.77 14.39 15.61 Ash, per cent .... .42 .47 .46 .42 .56 Rind, per cent . . . 28.4 27.0 19.2 31.0 32.0 Pulp less juice, per cent 27.7 24.0 25.9 24.0 24.5 Seeds, per cent . . . 0.8 1.6 0.12 Number of ce. of juice, average 107 86 65.4 71 38 Solid contents of juice by spindle .... 12.80 12.60 12.10 13.55 11.90 Total sugars in juice (by copper inversion), per cent 9.92 9.70 8.71 10.30 2.08 Cane sugar in juice (by polariscope), per cent 4.80 4.35 3.48 5.85 0.57 Citric acid, per cent 1.02 1.38 1.35 1.61 7.66 Nitrogen in fresh fruit, per cent .... 0.211 0.154 0.228 0.168 0.151 Albuminoids in fresh fruit, equivalent to nitrogen, per cent . 1.31 0.96 1.43 1.05 0.94 Analyses of Ash Lemons Potash (K2O), per cent Soda (NaaO) Lime (CaO) Magnesia (MgO) Peroxide of iron (FeoOs and alumina (Al,03) Br. oxide manganese (Mg304) . . . Phosphoric acid (PoOs) Sulphuric acid (SO.s) Silica (SiO.) Chlorine (CI) 48.26 76 29.87 4.40 Citrus Botany, Gross Structure, and Habits of Growth 63 foniia oranges contain about 30 per cent rind and 40 per cent juice when freshly picked from the trees. The percent- age of juice increases as the fruit is cured for the water in the rind is lost first by evaporation and transpiration. California Navel oranges will analyze about 10 per cent total sugars, 4^ per cent of which is cane sugar, the re- mainder being a mixture of other fruit sugars. Navel oranges contain about 1 per cent of citric acid. Lemons contain about 2 per cent total sugars, of which ^- per cent is cane sugar, and 7| per cent of citric acid. Harvest Season In California, oranges and lemons are harvested through- out the year. The orange season begins with Navels about November 15 in central California and moves south- ward. The last Navels are shipped from southern districts about May 1. During May and a part of June miscel- laneous varieties including seedlings and some late Navels are gathered and shipped. The Valencia harvest begins in central California in June and continues southward, the last of the crop going forward from the coast districts in November and thus overlapping the Navel crop of the next season. Lemon trees are picked over once each month or about ten times a year, the trees bearing fruit in all stages of growth from the blossom to the mature fruit at all times. Lemons should not be allowed to ripen on the tree . They should be picked when they have reached a diameter of 2yq inches in summer and 2^^ inches in winter and spring, regardless of color. 64 C'lfrus Fruits I.oiifirrifi/ Citrus trees are naturally lonji; lived. If planted on deep, rich soil and given good care, they should bear profit- ably for fifty years or more. IVIuch has been said in print about a natural limit of profitableness in the case of the Navel orange. This limit is sometimes placed at twenty- five years. The writer believes this to be a mistake. Navel oranges as well as other kinds of citrus will live and produce generous crops to a very great age, provided they are growing on deep, fertile soil and are well cared for. CHAPTER IV VARIETIES As stated in a previous chapter, the first oranges grown in CaHfornia were seedhng sweet oranges. Unhke the apple and peach, the sweet orange will come fairly true from seed, the fruit from practically all seedlings being marketable. Each tree, however, varies from its neigh- bors in many minor characters, such as size, producti\e- ness, season of ripening, seed content, flavor, and shipping qualities. The fruit from an orchard of seedlings lacks uniformity, which is one of the chief requisites of a com- mercial fruit product. Seedling trees grow very large, so large in fact that it is expensive to gather the fruit and often difficult or impracticable to inclose the trees in fumi- gating tents. For these and other reasons the old seedling orchards have been gradually cut down and replaced by budded trees or top-worked to improved varieties, until at the present time comparatively few remain. During the transition from seedling to budded orchards the question as to which of the many varieties available would prove the most i)rofitable was a favorite subject for discussion. By 1885, enterprising nurserymen had introduced most of the important varieties of the world, and these were F 65 66 Citrus Fruits tested alongside many local seedlings of special merit. Probably as many as one hundred diflFerent varieties were given trial. At the early citrus fairs such imported vari- eties as the Du Roi and Pernambuco were to be seen exhib- ited side by side with California productions such as Asher's Best and Bostram's Prize. The elimination of the less profitable varieties took place rather rapidly, and by the year 1900 we find the Washington Navel orange oc- cupying more land than all other varieties of oranges com- bined. At this time the two fittest survivors, the Navel and Valencia, dominated the field. DESCRIPTIONS OF VARIETIES OF ORANGES Washington Navel (Bahia, Riverside Navel). — Form rounded, slightly tapering at apex, somewhat longer than wide ; small umbilicus ; size variable, 2| to .3| inches in di- ameter ; color orange when grown near coast, deep orange when grown in interior valleys ; juice abundant, orange colored ; flavor excellent, acid and sugar well blended ; vesicles large, spindle shaped ; skin | to | inch thick, varying from smooth to pebbly ; size of secondary orange under umbilicus variable, often f inch in diameter. Seeds none, except in very rare cases. Tree semi-dwarf, ^^gorous, very precocious, prolific, thornless or with thorns only on vigorous shoots ; appearance of blossoms normal except for the fact that the anthers are cream colored and contain no pollen whatever. Introduced from Bahia, Brazil, 1870, by the late William Saunders, then in charge of U. S. Government propagating grounds at Washington, D. C. The Washington Navel well deserves the title "King of Oranges." Under the climatic conditions of California and Varieties 67 Arizona this variety approaches very nearly to the ideal orange. The dry air, bright sun, and cool nights, operating in conjunction with the skill of the grower and packer upon the natural qualities and character of this orange, have made it the greatest commercial orange in the world. These Fig. 16. — The earliest known illustration of a Navel orange. From Ferrarius' " Hesperides," 164G. thornless trees combine heavy and regular yields with a high color of the fruit, a silkiness of texture, and a general finish which is almost perfect. It is solid and full of juice of exceptionally high flavor, but it is entirely lacking in seeds. It is a very good keeper and travels well to the most distinct markets. It possesses moreover a natural trade- 68 Citrus Fruits mark, in the shape of a navel-like mark, which is beyond imitation and which is of great market value. More than eight million boxes of Washington Navels are now being grown and shipped out of California annually, and the prices received are encouraging a rapid increase in acreage. In California, the Washington Navel reaches its highest development in quality on the gravelly soils of the foothills in the warmer interior valleys. The yield, however, is not as heavy as it is near the coast, where the fruit tends to ripen later. On the deep heavy soils of the coast country, the skin tends to be somewhat thicker with a rougher surface and paler color. One characteristic of the W^ashington Navel is its tendency to sport or throw out occasional l)ranches bearing fruit of a different type. By far the larger number of these sports are retrogressions, and careless cutting of bud -wood for prop- agating purposes from trees containing such sports has re- sulted in a great lack of uniformity in existing orchards. Occasionally sports are found which possess some character of supposed value, and by the propagation of these new varieties have appeared. Among such offspring we note the following : Thomson, Buckeye, Na^'elencia, Nugget, and Australian. Thomson. — Fruit of medium size; skin thin and very smooth in texture ; ripens early. The quality of the Thom- son is somewhat inferior to the Washington Navel, but it has a superior appearance. For certain markets in some large cities where appearance rather than qiuility determines demand, it commands a premium of from twenty-five to fifty cents a box over the Washington Navel. For this reason, it is being grown on an increasing commercial scale. The Thomson was introduced by A. C.Thomson of Duarte, Los Angeles County, about 1891, and is generally thought Varieties 69 to be a bud sport from the Washington Navel. Consider- ing the story told by Mr. Thomson of his method of pro- ducing this form, it is possible that it may be a perielinal chimera ! Buckeye. — Fruit medium in size with peculiar bands or ridges of deeper orange color ; skin smooth and of fine texture ; ripens early. Introduced by R. M. Teague at San Dimas, California. Navelencia. — Fruit medium to large, smooth and thin- skinned ; season said to be somewhat later than Washington Navel ; more susceptible to frost than Washington Navel. Originated by A. C. Thomson, at Duarte, California. Nugget. — Fruit oblong, medium in size, smooth, solid, and thick skinned, often with an objectionable but characteristic crack or slit in the skin on one side ; young twigs slender and willowy, tree umbrageous with very brittle wood. Originated by J. P. Englehardt at Glendora. Introduced by R. M. Teague at San Dimas, California. Australian. — Fruit very variable, rough, coarse ; navel often closed ; skin thick, especially near stem end. Tree Fiii. 17. — One type of Australian Navel orange. 70 Citrm Fruits large with upright, open growth, sliy hearer. Strictly speaking, there is no such thing as the Australian Navel. The term is a misnomer in the same sense as the term English walnut is when applied to the Persian walnut. Tn common usage, however, the name applies to a certain rough-fruited and shy-l)earing sport of the Bahia Navel, which was un- wittingly introduced into California from Australia in an effort to secure the true Bahia. Some persons go further and call any undesirable sport an Australian, thus using the term as an adjective rather than as a noun. Some other persons apply the term x\ustralian to the rank growing wood resulting from water sprouts in the tops of the trees, which tend to produce coarse, rough fruit. This latter is clearly an improper use of the term. Valencia. — Form oblong, somewhat flattened with de- pressed ring at apex, tapering toward base ; size medium, color pale orange deepening with maturity ; skin smooth or slightly pebbled, thin but tough ; juice plentiful, flavor sub- acid ; seeds variable, sometimes three to six, often none ; season late, from June to November. Tree large, vigorous grower, prolific, thorns few and small. The Valencia hangs on the tree well during the summer but in interior valleys it is apt to turn green again in late summer. When grown in such situations, it should be harvested in May and June. In deep heavy soils near the coast, it can safely lie held till November or December. This famous orange originated in the Azores. Thomas Rivers, the English nurseryman, imported it, with other varieties, from the Azores into English glass-houses and first catalogued it in 1865 under the name "Excelsior." S. B. Parsons, a Long Island nurseryman, bought trees from Rivers and brought them to America about 1870. He kept them in his greenhouse for several years and then moved them to Varieties 71 his nursery near Palatka, Florida. Parsons sold some of these trees to E. H. Hart, of Federal Point, Florida, who gave the variety the name "Hart's Late" or "Hart's Tar- diff." Fruit was first exhibited before the Florida Fruit Growers' Association on April 25th, 1877. A. B. Chapman, of San Gabriel, California, imported a number of varieties of citrus from Thomas Rivers al)out 1870- 72. One variety labeled Navel, turned out not to be a Navel, but of distinct value on account of its ripening very late in the season after other varieties were off the market. Finally, at the suggestion of a Spanish laborer, Mr. Chapman called the orange "Valencia Late" and many trees were propa- gated and sold under this name. California nurserymen early secured stocks of Hart's Tardiff from Florida, and many thousands of trees were planted. When it became evident that these were the same as the Valencia, the latter name was adopted and is now used exclusively in California. This name has become so well fixed in the trade and market reports as well as in the every-day speech of the people that it is idle to attempt to change the name in order to conform to the rules of horticultural nomenclature. The fame and popularity of the Valencia orange has been greatly advanced in California by the wonderful record made by a superb orchard of this variety owned by C. C. Chapman at FuUerton in Orange County. Mediterranean Sweet. — Form round or somewhat flattened ; size medium to small ; color deep orange ; skin of fine texture ; juice abundant, very sweet ; seeds few, small ; season April to May ; tree semi-dwarf with small narrow leaves very thickly set, almost thornless. Introduced and renamed by T. A. Garey of Los Angeles about 1870. Secured from Thomas Rivers of England. 72 Citrus Fruits Paper Rliid (Paper Rind St. Michael). — Form round; size small, solid with high specific gravity; color yellow, or pale orange ; skin very thin and very smooth ; jnice ai)un- dant, colored, with rich vinous flavor; seeds three to six in number, medium sized ; season March to May ; tree semi- dwarf, medium thorny, very productive. Introduced from the island of St. Michael. Rtihif (Blood). — Form round or slightly ol)long, sometimes navel marked ; size medium ; color deep orange or reddish when fully matm-e ; skin smooth ; juice deep orange in color changing to red as fruit matures ; flavor very rich and vinous ; seeds many ; season March and April, tree of medium size, compact growth, almost thornless. Imported from Mediter- ranean districts. Jaffa. — Form round ; size medium ; color deep orange ; skin smooth or slightly pel:)bled ; juice abundant and of excellent quality ; seeds many, large ; season March to May ; tree medium sized, more resistant to cold than most other sweet oranges, almost thornless. Imported from Palestine, where it is largely grown. Joppa. — Form oblong, slightly shouldered ; skin thin, somewhat pebbled ; juice abundant, sweet, and of fine flavor ; seeds few or none ; season March to July ; tree large, thorn- less. Originated in 1877 by A. B. Chapman of San Gabriel, California, from seed secured from Joppa, Palestine. Crafton (Crafton Late). — A late seedling, originated by Myron H. Crafts, several large budded orchards of which are still in bearing in the vicinity of Crafton, California. It is marketed during May and often brings very good prices. LEMONS In the early days of the industry a large number of Euro- pean varieties were tested, but few were found suitable to Varieties 73 the California conditions. Many seedlings were raised also, most of Avhich proved disappointing in some important respect. At present new plantings are limited chiefly to two varieties, the Eureka and the Lisbon. While a few old orchards of VilUifrancas are still maintained, but few are being planted. The Eureka is rapidly gaining in popularity Fig. is. — Eureka lemon, uncured. over the Lisbon and it appears that this will soon be the only variety planted on a large scale. Eureka. — Form oblong, apex nippled, base tapering ; size medium ; rind smooth, glossy, sweet ; juice abundant, clear, strongly acid, flavor good ; seeds few, often none. 74 Citrus Fruits J. H. Needham, in an essay before the Pomological Society at Covina in 1898, says : "The advantages of the Eureka are its comparative freedom from thorns, its tendency to early bearing, and when properly trained to enormous crops when it comes into full bearing, and its continuous blooming and setting of lemons all the year, especially in sections com- paratively free from frost. The objections are its tendency to set its fruit on the tips of the branches, and the inclination to grow long canes with but few laterals and to drop its leaves on the long canes or branches, thus leaving the limbs and fruit too much exposed to the hot rays of the sun in the heated term of summer." The Eureka lemon originated from a seed planted about 1870 by C. R. Workman in Los Angeles. Workman and Pres- ton began to propagate it, but later sold all the stock to Thomas A. Garey, of Los Angeles, who propagated it extensively and sold it under the name Eureka. Lisbon. — Form oblong or obovate, apex oblique, nippled wath a characteristic crease to one side of the nipple, base tapering sharply to calyx, which is large ; rind thin, smooth, sweet ; juice abundant, clear, and strongly flavored ; seeds few, sometimes none ; tree large, a strong, vigorous grower, foliage thickly set, not precocious, very thorny. The Lisbon bears its fruit uniformly throughout the tree. The heavy foliage protects the fruit from sunburn. The tendency is to bear one large crop maturing in winter, with a small amount of summer fruit. Introduced from Europe. Villafranca. — " Form oblong, slightly pointed at the blossom end, rind thin, without any trace of bitterness ; acid strong, juicy ; nearly seedless. Tree almost thornless, branches spreading and somewhat drooping, foliage very abundant, which protects the fruit from sunburn. The Varieties 75 tree is a strong grower and is considered less susceptible to cold than most varieties. Introduced from Europe. "The advantages claimed for the Villafranca are that it makes a more compact tree and bears its fruit, more uni- formly over the entire tree, but it requires at least one year longer to come into bearing, and tlie fruits on young trees are shorter when they have the requisite diameter for picking than either the Eureka or the Lisbon." ^ Other varieties still to be found in old orchards and collec- tions are Bonnie Brae, Genoa, Sicily, Messina, and Milan. POMELOS Marsh. — Form flat or obovate ; size small to medium ; color light yellow ; rind smooth, variable in thickness ; juice ' Lelong, "Culture of the Citrus in California," p. 1G7. 76 Citrus Fniit.t Fig. 20. — Seedless pomelo, flowers and fruit. From Volckamer's " Hesperides," 1708. abundant ; flavor fair ; pith large, open ; seeds none or one to six ; season March to July or later ; hangs on trees well all summer. According to Hume/ this variety was introduced by C. M. 1 " Citrus Fruits and Their Culture," p. 120. Varieties 77 Marsh of Lakeland, Florida, about 1895 or 1896. The original tree was a seedling growing in Lakeland, and was at the time of the freeze fully sixty years old. The Marsh is the chief variety of pomelo grown commer- cially in California and Arizona, although the following may be occasionally met with and are doubtless deserving of a wider planting. While seedlessness is a very desirable character in a fruit, it should not be allowed to outweigh such characters as flavor, juiciness, and quality. California is in need of a variety of pomelo better suited to the conditions than any now available. Nectar {Duarte Seedling). ■ — ^ A seedling tree brought from Florida and fruited at Duarte, California. The fruit is round and solid with smooth skin of pale yellow color. The seeds are few and the flavor excellent. Duncan. — A flat fruit with rather thick skin and flesh of grayish green color, seeds few, season late, quality good. Introduced from Florida. Triumph. — A fine-appearing fruit and full of juice as well as seeds, of which there are many. Somewhat lacking in flavor. Imperial. — Size medium to large, rind very smooth, medium thin, and of fine texture ; little rag ; juice abundant and of fine aromatic flavor. R. M. Teague says of this variety : " It is one of the best keepers and shippers. The tree is a strong upright grower and a heavy cropper." Colton {Colton Terrace). — A seedling grown at Colton, California. Size medium to large, heavy, subacid, and deli- cately l)itter ; seeds many ; skin smooth ; oil cells very small ; light lemon color, turns slightly orange color when mature. Pink-fleshed. — A prolific variety imported from Cuba. Flesh deep pink, coarse, and of poor quality. Seeds many ; tree very large and ornamental. 78 Citrus Fruits MANDARINS The Mandarin oranges grown commercially in California are practically all of one variety, the Dancy, commonly known as the tangerine. On account of the confusion in name, it may be well to emphasize the fact that " tan- gerine" is the trade name for one variety of Mandarin orange, the proper name for which is Dancy. The Satsuma Fig. 21. — Dancy Mandarin orange. is not grown commercially in California and is represented only by occasional specimens in gardens and nursery collec- tions. Such collections often contain specimens of King, Beauty, Mikado, Oneco, and a few others. Dancy. — Form oblate ; size medium ; color very deep orange red ; glossy ; rind smooth, except about stem end, which is nippled, apex depressed ; segments separating readily ; juice abundant, colored ; flavor rich and sprightly ; seeds five to ten or more, small ; season January to February. Tree of upright growth, fruit borne largely on the extremities Varieties 79 of the branches ; somewhat thorny. Parent tree raised from seed by Col. George L. Dancy at Buena Vista, Florida. In- troduced into cultivation about 1872. Sai.suma (Unshiu). — Size small to medium, 2 to 3 inches in diameter ; shape flat, a little pointed next the stem ; color bright orange ; skin rough, wrinkled next the stem, very loose and easily separated from the flesh ; core, almost none, represented by a cavity often three-eighths inch in di- ameter in center ; seeds none ; flesh orange color, darker than the skin, not so juicy as some ; flavor very sweet, rich, very aromatic, peculiar ; quality very good ; season early. This variety is thornless and a dwarf grower. It will endure more cold than any other variety of edible citrus fruit except perhaps some of the hybrids mentioned below. Should be worked on Citrus trifoliata stock or sourstock. Introduced from Japan about 1876. MISCELLANEOUS VARIETIES Swingle-Webber Hybrids. — In 1892, W. T. Swingle and H. J. Webber of the U. S. Department of Agriculture under- took to produce new and improved varieties of citrus fruits by hybridization on an extensive scale. Several new types have been produced, examples of which are Citranges and Tangelos. The citranges are crosses between the common sweet orange and the trifoliate orange. The Rusk, Willits, Norton, Colman, Savage, and Rustic have been described. The fruits of these hybrids are intermediate in character between their parents. They are not nearly so good as sweet oranges, but they may be used for making soft drinks, pies, and marmalades. Their special advantage lies in their re- sistance to cold, which enal)les them to grow a hundred miles or more beyond the northern limit of the sweet oranges. 80 Citrus Fruits In California they are as yet grown only as specimens for exhibition purposes. The Thornton is a loose skinned tangelo which resulted from crossing the pomelo and tangerine. The juice is sweet, lacking the hitter of the pomelo. The Sampson tangelo is the result of crossing the pomelo with pollen of Dancy. The skin is loose like the tangerine, but the flavor includes some of the bitter of the pomelo. The Weshart and Trimble are crosses between the Dancy and Parson Brown. Fig. 22. — Satsunm Mandarin orange. The fruits are larger than the Dancy, which they resemble otherwise. Several thousand hybrid seedlings of several generations are now being grown by the Department of Agriculture and additional varieties of merit may come to light in the future. Citron. — Citron is not grown commercially to any extent in California, although good specimens of the plant may be found in many parts of the state and there is at least one good-sized orchard. The tree is small in stature with a Varieties 81 shrub-like growth. It is more tender to frost than the orange, but less tender than the lime. As early as 1880, experiments showed that California-grown citron, when properly processed or candied, was equal in every respect to the imported article. The consumption of candied citron in the United States is very small compared with that of oranges and lemons, and this probably is the main reason why so little interest has been taken in it. There appears to be no good reason why California should not produce all the candied citron consumed in this country. Most of the varieties of Europe have been introduced for trial. The Corsica appears to be one of the best. Shaddock. — The shaddocks are of no commercial im- portance. Occasional trees may be found in collections and in yards and gardens throughout the citrus belt. They appear to vary in resistance to cold, some being as hardy as the orange. The fruit is very large, round, oblate or pear shaped ; skin very thick, sometimes two inches thick ; seeds many or none ; flesh pale yellow or reddish, juice acid and often very bitter ; in some forms the young growth is pubes- cent. Trees ornamental, but not more so than the pomelo, which is both useful and ornamental. Lime. — Three kinds of limes are grown for home use to a limited extent in California. The Sour or West India lime, together with the Rangpur, are used for cooling drinks while the Sweet lime is eaten out of the hand like the orange. Limes have never been grown commercially in California. All but the Rangpur are very tender to frost, even much more so than the lemon. The Rangpur is said to be fully as hardy as the lemon. In the early days a sour form of Mexican lime was much planted as a hedge plant aroimd orange orchards. They proved too tender for most localities and were difficult to fumigate and keep free from Fig. 23. — Nagami kumquat Varieties 83 scale insects. For these reasons they liave mostly dis- appeared. Kumquat. — In California the kumquats are used chiefly as ornamentals, although a few find their way into the markets and an occasional small shipment is sent out of the state. They are especially suited to pot culture, when budded on Citrus trifoliata root, and are convenient to move about as desired on verandas and in formal gardens. The fruit is small, about one inch in diameter, with sweet aromatic rind. The fruit may be eaten fresh or made into delicious preserves. The Marumi kumquat is most hardy to cold. It has round fruit, borne in great abundance, ripening in October. Twigs somewhat thorny. The Nagami kumqiuit is oblong, slightly pear shaped ; fruit golden yellow ; rind smooth, aromatic, and spicy. Tree thornless, slightly more tender to frost than Marumi. Swcd lemon. — This form of citrus is met with only in collections, as there is no market demand for a sweet lemon. It is a question whether this should be grouped with the lemons or with the oranges. The fruit is like a lemon in shape but the flowers are white like those of the orange. The Trifoliata. — In the early days this species was grown to a considerable extent in California as a hedge plant. These hedges have been largely done away with, and as the plant is not needed as an ornament, it is rapidly becoming rare in the state. CHAPTER V THE CITRUS NURSERY The day of the seedling orange grove is past in Cali- fornia. Now all trees for new plantings are bndded as a matter of course. Many of the large planters prefer, and find it highly profitable to grow their own trees. Yet the business of raising citrus trees for sale has reached large proportions. Citrus nursery stock not only fills the home demand, but is shipped in large quantities to many foreign countries. THE SEED-BED The first step in the production of a citrus tree is the raising of the root or stock upon which the desired variety is to be budded. The comparative value of all the diflferent stocks will be discussed in Chapter X. We will simply say here that at present the demand is about as follows : sour-stock, 85 per cent ; sweet-stock, 9 per cent ; pomelo, 5 per cent ; and all others, 1 per cent. Sour-stock seed comes from the wild thickets of Florida and Cuba, and is sold in California for from $30 to $50 a bushel. Between five and six hundred bushels of sour orange seed was planted in California in the year ending June 30, 1913. M The Citrus Xursrn/ 85 Fig. 24. — Citrus beed-bed uudci- lulli 86 Citrus Fruits This seed may he secured in the fall and kept in a cool, dark cellar. It should not become excessively dry. Sour seed runs about 30, ()()() seeds to the bushel, half of which should come up and produce trees. Sweet orange seed is secured from the various seedling orchards in California. It will not endure drying, but must be handled quickly and kept moist. The seed stores do not keep sweet seed on hand in quantity, but on receipt of an order will send a man with a seed separating machine to a cull heap near some packing-house, secure the amount of seed desired, and forward immediately to the purchaser in a wet condition. Such seed must be planted at once. The price is usually from .^18 to $25 a bushel, which contains about 35,000 seeds. Pomelo seed is secured either locally or from Cuba. It will stand dry- ing to a small extent only. Rough lemon seed may be handled much like sour orange seed. After the freeze of January, 1913, it was found by experi- ment that the seed in oranges which had been frozen was viable, although dark in color. Almost as good germina- tion was secured with seed from frozen as from sound oranges. It is an established custom in California to grow citrus seedlings under a lath shelter, although one large nursery- man near the coast has broken away from this custom and has secured good results by planting entirely in the open. In the hot interior some shelter is necessary, but the trees grow in height faster and are ready for market quicker if grown inider shelter anywhere. The shelters are cov- ered with one-inch laths alternating with one-inch open- ings, supported by uprights set at convenient distances. The Citrus Nursery 87 The lath are usually nailed to cross pieces in sections of suitable size to be handled by two men. The shelter rests about eight feet from the ground and the lath should run north and south. The soil for the seed-bed should be deep, sandy loam, free from stones and well-drained. Virgin soil is best, but if that is not obtainable, good, rich grain land will answer. It should of course be worked up into a fine state of tilth, leveled, and slightly firmed with a light roller. If dry seed is used, it should be soaked for twenty-four hours before planting. If the bed is to be irrigated by running water through furrows, the ground is laid off in rows twelve inches wide with very shallow furrows about eight or ten inches wide. A broad, shallow, slow stream of water is needed to soak through such rows. The seed is planted broadcast on these wide rows, e^Try sixth row being left vacant for a walk. In case the bed is watered from above by automatic sprinklers, as is usually the case, the seed is broadcasted over the entire surface of the ground except for a twelve-inch path every ten feet. In some cases the seed is simply planted about one inch deep in the loose soil and then thoroughly watered. In most cases, however, the seed is gently pressed into the soil with a board and covered from ^ to 1 inch deep with clean coarse river sand especially provided for the purpose. This covering of sand prevents the ground from baking and also keeps the surface dry. The seeds are placed about one inch apart each way and if half of them or even an average of thirty to the square foot grow, the stand is considered satisfactory . One of the greatest dangers to the seed-bed is the pos- 88 Citrus Fruits sibility of infestation by the "damp-off" fungi. This disease works very rapidly, coverina; a large area in a single night and killing the seedlings just after they come up. This trouble may usually be prevented by keeping the surface of the ground as dry as the requirements of the seedlings will permit. The covering of sand allows the water to pass through to the roots while the surface dries again very quickly. The usual time of planting is April, and most of the plants should be large enough to sell one year after planting. After the seedlings are two months old they may be watered more generously every two or three weeks as necessary. All weeds should be kept out of the beds, and a sharp watch must be kept for gophers, moles, and ants. The plants are sold for from $20 to $50 a thousand when they are about a foot high. The beds are usually gone over twice, the smaller plants remaining for two years. It is hardly necessary to point out that the plants first pulled from the bed are much more desirable than those which require two years to reach marketable size. In ordering seed-bed stock "first pull" plants should always be specified. Xo manure or compost of any kind should be used in the seed-beds for fear of encouraging the "damp-off" fungi, which are usually more serious in proportion to the amount of freshly decaying organic matter in the soil. A moderate dressing of commercial fertilizer high in nitrogen will accelerate the growth of the plants. Often no fertilizer is used. After the seedlings have safely passed the stage when they are liable to damp-off, they may become infected The Citrus Nursery 89 with brown-rot guin-disease. In such cases they \\ill exude gum just above the ground and may be girdled and killed. Where there is any large amount of such gumming, a thorough spraying with bordeaux-mixture is recommended. Sour-stock is very resistant to gum- disease in the orchard, but this is not always the case in the seed-bed. WTien seed-bed stock is to be dug, the soil is first thor- FiG. 25. — Citrus seed-bed in the open. oughly wet, the roots slightly loosened with a long tined spading-fork, and the plants drawn by hand. A varying proportion of the plants will have a crooked or Z-shaped tap-root known as " bench-root." When the seed-coat is tough, the root has difficulty in piercing it and often makes several turns before getting out. This may be partly pre- vented by soaking the seed over-night before planting. All such plants are inferior and should be discarded. All 00 Citrus Fruits Fig. 2G. — Bench-rooted orange seedling. plants which have gum-dis- ease should also be thrown away. After grading, the plants are tied in bunches and their tops chopped oft" squarely with a hatchet about eight inchesabove the crowns. They are then packed tightly in boxesorbagswith the tops ex- posed and with moist sphag- num moss about the roots. Citrus seed-beds are likely to become infested with scale- insects or other pests, espe- cially if situated near infested orchards. In many counties, horticultural inspectors have strict regulations in regard to the admission of nursery- stock shipped from other counties. Such local regu- lations are by no means uni- form for the whole state. It is wise to confer with the ap- propriate officer in each case before the plants are dug in order to learn just what kind of treatment will be required. Usually the plants are dipped, all but the roots, in the fol- lowing solution : The Citrus Nursery 91 Resin 20 1b. Caustic Soda 8 lb. Fish Oil 3 pt. Water 100 gal. PLANTING SEED-BED STOCK For the planting of seed-bed stock, a deep rich loam, free from stones, should be selected. It should contain just enough clay to stick together well when the trees are balled. The site for the planting should be as free from frost as possible, as newly set buds are very susceptible to cold. The stock is planted eighteen inches apart in rows three and a half or four feet apart. Especial emphasis is here laid upon the fact that the roots of citrus plants are very susceptible to injury from drying, and if a plant is left in the sun, with its roots exposed, for more than a few moments, it is almost sure to fail to grow. The best plan is to take all the plants into the field in the boxes of sphagnum covered with wet sacks. Only a few should be handled at a time and in such a way as not to expose the roots at all. The plants are usually set with a dibble or spade, great care being taken to get the roots in straight and not to set the plants deeper than they grew in the seed- bed. In planting citrus trees of any size or kind, it is a safe rule not to vary the depth of planting. The soil around the plants should be well firmed to bring the roots in close contact with moist earth. Irrigation water should follow the planters down each row as the work proceeds. After the soil is well irrigated the plantation should be gone over and those plants which on account of their small size did not have a part of the top trimmed off 92 Citrus Fruits at the seed-bed should be cut back about fifty per cent. These small plants which escaped the trimmer's hatchet are almost sure to die unless headed back in the same proportion as the others. Budding stock handled as described, and j^roperly culti- vated and irrigated, should be large enough to bud at the end of one or two years, usuall\' eighteen months. An application of about one-half ton per acre of special nursery stock commercial fertilizer will save time in growing the plants to budding size. Every effort should be made to encourage a vigorous growth. It is false economy to bud seedlings which are too small ; the ideal size being from I to I'g inch in diameter three inches from the ground. PROPAGATION Many writers make the statement that citrus trees are propagated by budding, grafting, cuttage, and layerage. This is somewhat misleading, inasmuch as budding is the universal method employed in America. Lemon cuttings may be made to root, but orange cuttings are so difficult as to be out of the question entirely. The few lemon trees that have been grown from cuttings have been inferior and have mostly passed out of existence. Layering is never used and grafting is very rarely resorted to except in the case of old trees which have been frozen to the ground. INIost old trees which are top-worked are budded. The writer has seen buds successfully placed directly into orange trunks which were a foot and a half in diameter, although such a practice is rare and not to be recom- mended. The Citrus Nursery Cutting Bud-wood The success of the citrus orchard depends to a very large extent upon the care used in cutting the bud-wood. This is due to the fact that a certain propor- tion of the trees in many orchards belong to undesirable types. This particular phase of the subject will be reserved for a more extended discussion in Chapter VII. Suffice it to say here that too much pains can hardly be taken in selecting the mother trees from which the buds are to be cut. Citrus buds should be cut from round, plump wood taken from the fruiting branches. It is usually easy to find plenty of suitable bud-wood on lemon trees, but with oranges, Fig. 27. — Orange bud-wood. 94 Citrus Fnals and especially Navel oranges, this is often difficult for the reason that the best trees are devoting their energies to bearing rather than to growing plump bud-sticks. The small angular fruiting twigs are not large enough to use to advantage. On this account it becomes necessary to give Navel mother trees a preparatory pruning a year before the buds are wanted. The trees are thinned out and cut back uniformly in all parts in order that there may be a more vigorous growth of fruiting wood. This pruning should not be carried too far or water-sprouts may result. Bud- sticks about a foot long and the size of a lead pencil made up of one- and two-year-old wood is best. Current growth is too tender and three-year-old wood contains many blind buds or buds which will be very slow to start. Uniformity in starting the buds is much to be desired, and the more care is used in collecting buds of the same degree of matu- rity, the more uniform the nursery will be. The leaves are cut off, leaving a short stub for a handle. The cutting may be done in mid-winter and the accumulated wood buried in slightly moistened sand for two or three months. The wood will cure and callous on the lower end, and cured wood is supposed to give more uniform results. ]Most budders prefer to keep the bud-wood in boxes of moist sphagnum because the sand will dull the budding knives unless the wood is carefully washed. It is not necessary to cure the buds, but it is often more convenient to cut the buds all at one time and keep them until used. It is best to select bud-wood as free from thorns as possible for the reasons given in Chapter III. A great deal of argument has been indulged in over the question of whether buds from sucker growths or water- The Citrus Nursery 95 sprouts are as desirable as buds from the fruiting brush. It is unwise to use buds from rank growing water-sprouts because an excess of food is one of the chief causes of variation ; and as these buds ha\e a great excess of food, they are somewhat more hkely to grow into sporting trees than are buds from fruit w ood. This does not mean, how- ever, that good trees have not been grown and may not again be grown from sucker buds. We simply take the position that it is an unwise policy for the reason given. Time of Budding Citrus stock may be budded at any time of the year or whenever the bark will slip, but the best time is during the months of October and November, in which case the buds usually remain dormant until spring. Stocks upon w^hich the buds fail, may be rebudded in April or May. It often happens, unfortunately, that a certain proportion of fall set buds start into growth immediately, thus ex- posing a few inches of very tender growth to the dangers of winter. In such a case, the number of orchard heaters set in the nursery should be increased and the fires started at the first indication of frost. Method of Budding In California, the usual method of insertion is the shield or T method. The bud-stick is grasped firmly with the tip toward the operator. With a very sharp budding knife the bud is cut by inserting the blade about one-half inch below and drawing it beneath the bud and out about one-half inch above, thus cutting a bud about one inch 96 Citrus Fruits loiifi;. The bud is held firinl\- ])etween the thumb and the knife l)hide while a slit is eut in the bark of the stock about three inches above the ground and one-half inch long. At the top of this slit, a cross cut is made with the edge of the blade of the knife inclined downward. The bud is then inserted in this slit, being careful to have the leafscar or bottom of the bud down. The back of the point of the knife is then placed on the leafscar and the bud pushed down until the upper end is be- low the cross cut, and in any event un- til the pressure of the bud begins to split the bark beyond the previously made slit. A strip of waxed cloth is then wrapped c[uite firmly around the stock five or six times so as to cover the bud completely. Some budders prefer to leave the eye exposed but this is not necessary. Buds are usually set on any side as re- gards the points of the compass, or in other words, the side most convenient to the budder. The bark usually slips, and the buds take better, directly under a small branch. Some budders prefer to use the inverted T method. The cross cut in the bark of the stock is made lower and Cutting a The Citrus Nursery 97 the bud pushed upward instead of downward into place. The inverted T is somewhat better for fall budding, as the cross cut or obstruction when placed below the bud tends to produce a quiescent state which is desired during winter. The cross cut when placed above the bud tends to produce a strong lateral growth and is therefore best for spring budding. Most seedlings tend to branch close to the ground and as a result buds are often placed quite close to the ground. This is a mistake in most cases, especially when using sour orange as a stock. This stock owes its popularity largely to its resistance to gum- disease, but when buds are placed low this resistance is much reduced. The object should be to keep the wood of the scion as far from the ground as practic- able in order to avoid gum-disease infection, which comes from the soil. If, on the other hand, buds are placed too high, a crooked and ugly trunk will result. While high budded trees are less comely and do not sell as well on account of the crook in the trunk, still they are the more to be desired, especially when intended to be Fig. 29. — Making incision in stock. 98 Citru.s- Fntitf planted on heavy soils or near the eoast, where gnni-dis- ease is prevalent. After about ten days, the buds should be unwrapped and examined. If they have taken, as evidenced by a grayish line of callous tissue forming around the edges, the wrap- pings are loosened, to be removed entirely after about thirty days in the case of the fall buds and twenty days in the case of spring buds, or whenever the bud is w'ell healed. In the case of fall buds which have re- mained dormant, as they should during winter, the tops of the stock are cut back in the spring to within six inches of the buds in order to increase the sap pres- sure and force them into a more uni- form growth. The promptness with which a bud starts depends to some extent on its age and position on the bud-stick. Uni- formity of growth is greatly to be desired in the nursery, and such cutting back tends to force all the buds to start more nearly at the same time. The six inches or more of stock which is left affords a certain pro- tection to the young shoot and reduces the possibility Fig. 30. — Inserting bud. Citrus Nursery 99 of the bud being involved in any dying back which may occur. After the young shoot has grown eight or ten inches the stub of the stock is sawed off smoothly, the edges trimmed with a sharp knife, and the cut surface covered with liquid grafting wax. In the case of spring set buds, the same custom prevails except that some- times the stocks are only partially cut back at first. With late set buds there is sometimes a dan- ger of the superabun- dance of sap during hot weather "drown- ing out" the buds if all the top of the stock is removed too suddenly. Occasion- ally the tops are "lopped" or cut half through and bent down in the middles, in order to gradually change the flow of the sap. are removed entirely after a month or six weeks. Citrus budding is often done l)y expert budders by con- tract at about $10 a thousand, the budder guaranteeing a 95 per cent stand and furnishing his own buds, wrapi)ing cloth, and the like. Eight and a half dollars a thousand is a common price when buds are furnished. This of course applies to regular fall budding. Tj-ing inserted hud. They 100 Citrus Fruits Traiuiug the Young Tree In order to insure a perfectly straight trunk the young trees are trained to stakes. The .stakes may be set soon after the buds have started growth. The stakes used in Cahfornia are ordinary building laths. They are driven into the ground close l>y the stock on the side next the scion. As the young shoot grows it is tied to the stake with soft raffia. A tie is made every three inches, the raffia being drawn up snugly under a leaf. The rough unfinished surface of the lath is an advantage, as it pre- vents the raffia from slipping down. Careful attention to tying is necessary in, order to secure straight trunks. While going over the trees for tying it is also necessary to remove any side branches which may put out, as well as the numerous suckers which arise from below the bud. These sprouts should be rubbed off with the thumb while still very young, and this necessitates going over the trees every three or four weeks during the first summer. Nursery trees should be allowed to grow three feet tall and then headed back to 27 or 30 inches. This will insure the main branches being set upon stronger wood than if the terminal bud was pinched as soon as it reached the desired height. Branches which are to be the framewc^rk of the future tree are encouraged to put out on all sides and distributed over the upper twelve inches. From three to six main branches are sufficient. The old custom was to allow the framework branches to arise from near the same point. Experience has shown that such branches split down badly and require much bolting when the trees grow old. This is being abandoned, especially The Citrjis Nursery 101 with lemon trees, in favor of the less comely but more de- sirable distribution of main branches. Fic. 32. — Orange buds in nursery row tied to lath stakes. Often a tree will make several growths before it reaches the top of the stake. The end of each growth is marked by a ring or node of thickened tissue. There is a wide- 102 . Citrus Fruits spread belief that a tree with several of these nodes on the trunk is to be preferred to one which made one growth to the top of the stake. 'J'he reason assigned is that it indi- cates slow growing and heavy fruiting qualities. It is doubtful whether there is sufficient basis in fact for this belief, although there are some arguments in its favor. It is not unlikely that in the case of the Washington Navel orange there may be some correlation between the num- ber of nodes and fruitfulness, but this is probably not the case with lemons. The citrus nursery should be thoroughly cultivated and irrigated and the trees kept in vigorous growth. Com- mercial fertilizer should be applied liberally, usually a ton to a ton and a half to the acre of a complete fertilizer high in nitrogen. One or two years are required to grow a marketable tree. We find, therefore, that a total of from four to six years is required from planting the seed to set- ting the trees in orchard form. Trees are graded and priced according to caliper measure- ment one inch above the bud. Well-grown one-year trees are often acceptable, but usually two-year trees are much better. Prices in California vary from fifty cents to one dollar and a quarter a tree. PREPARING TREES FOR SHIPMENT Citrus trees may be dug with naked roots, cut back to the trunk, shipped long distances, and planted with perfect success ; but on account of the fact that it is difficult to always see that the tender roots are not exposed, there is much loss from the carelessness of laborers, and the The Citrus Xurscri/ 103 custom of balling trees has become general in California. Balled trees are much less perishable, may be handled with more assurance, do not require all the top to be removed, do not need to be reheaded, and make a somewhat better showing the first year. On the other hand, the cost of 1 1 Fig. 33. — Healing of the bud union. balling is great and the freight on thirty to forty pounds of earth with each tree adds considerably to the cost. It is recommended, therefore, that trees be balled where the distance to be transported is short or when inexperi- enced men are to do the planting. Where the owner is able to look after the planting personally the trees may be dug with naked roots and a considerable saving on freight and expense of balling will result. Where trees are to be moved only a short distance, as from one part of a ranch 104 Citrus Fruits to another, the following method is sometimes used. Short sections of ten-inch pipe are placed over the trees and driven into the ground, thus cutting all roots but the tap-root, which is cut with a spade. The trees are Fig. M. — Hailing orange trees in the nursery. then moved and the core of earth containing the trees is slipped out of the pipe into the hole prepared, the pipes being used again and again. When trees are to be balled, a trench a foot wide and fifteen inches deep is dug alongside of a row of trees and with careful work the tap-root may be cut and the tree The Citrus Nursery 105 lifted with a ball of earth. This is carefully wrapped in old sacking and firmly tied with strong cord. The top is cut back somewhat, the leaves remo\ed from the trunk, and the trees are ready for shipment. A bailer and tyer work together and in good soil shoidd turn out about one hundred and se\enty-five trees a da>'. Counting the men engaged in digging trenches and defoliating, a crew of twenty-five men should dig and ball about fifty trees a day for each man in the crew\ When a few balled trees are shipped, they must be boxed at considerable expense. In the case of carload lots, they are simply stacked closely together in ordinary box cars, the balls resting on a layer of moist straw on the bottom of the car. En route the balls should be kept moist, but not so w^et as to start growth. California now produces upward of a million and a quarter citrus trees a year, many of which are shipped to various foreign countries including South Africa, New Zealand, and India. Foreign shipments always go forward with bare roots firmly packed in sphagnum moss. CHAPTER VI HORTICULTURAL INSPECTION AND QUARANTINE California has had much experience with horticultural statutes. Many dift'erent laws ha^•e been passed and amended from time to time during the last thirty years. During this time there has been hardly a session of the state legislature which has not changed the law in some particulars. The citrus industry is so vitally concerned with the activities of the State Commission of Horticul- ture as to warrant a description of this important agency. In INIarch, 1908, the State Commissioner of Horticulture published a handbook containing all the laws together with the court decisions and legal opinions relating thereto, corrected to that date. More recent laws, together with a number of quarantine orders, may be found in the Com- missioner's "Monthly Bulletin," Vol. II, pp. 337-351, 1913. The ordinances of the different counties relating to the movement of nursery stock from one county to another may be secured from the respective County Horticultural Commissioners. THE STATE COMMISSIONER OF HORTICULTURE This official is appointed by the Governor for a term of four years or until his successor is appointetl. 106 Horticultural Inspection and Quarantine 107 While the state law, approved April 26, 1911, directs the Commissioner to collect books, pamphlets, and periodi- cals and acquire all possil)le information by correspondence for the furtherance of the horticultural industries, still his principal function is that of a police officer. He is by virtue of his position the state horticultural quarantine officer, and as such is responsible for the rigid exclusion from the state of injurious insects and plant diseases, and the prevention of any further dissemination of such pests as are already established m certain localities within the state. In order to enforce the state quarantine law approved January 2, 1912, the Commissioner maintains an office with a force of inspectors at San Francisco, another at Los Angeles, and a third at San Diego. These hispectors go through the cargoes of every ship arriving from any foreign port or from Honolulu, and the baggage of every passenger. If any plants, fruits, or seeds are found to be infested with injurious insects or diseases, they are fumigated at the expense of the owner, or treated in such a way as to kill the pests. If this is impracticable, the plants are destroyed or, at the option of the owner, returned whence they came. In some cases the State Commissioner may, with the written approval of the Governor, issue a quarantine order against certain fruits or plants from certain countries. Such articles are then considered contraband and, if an attempt is made to introduce them, are confiscated and destroyed by the inspectors regardless of whether they are infested or not. The State Commissioner may appoint the County Horti- cultural Commissioners or their agents special quarantine officers for the purpose of inspecting shipments coming 108 Citrus Fruits from the Eastern states or Europe and hilled to interior points in California. The common carriers are by law forbidden to deliver to a consignee within the state any shipment of horticultural goods until such shipment has been inspected, declared free from pests, and formally released in writing by a duly appointed horticultural in- '^ .flUiiMidMl f iiW ^■"^W^»"^*i^"i^*l**4 lllliH ^ ^^^^l^g^^J^ Fig. 35. — A -shipment of defoliated balled orange trees. spector. The inspector may exercise his discretion in re- gard to the disposition of infested shipments. He may rid the plants of pests by fumigation or other means and then release them upon payment of the costs ; or if in his judg- ment the infestation is severe or the pest particularly dan- gerous, he may destroy the goods or cause their reshipment out of the state. As an example of a quarantine order now in force we may Horticnltiiral Inspection and Quarantine 109 cite Order No. 21, which forbids the shipment of any of the forty listed host plants of the citrus white fly, Aleyrodes citri and Aleyrodes nuhifera, from North Carolina, South CaroHna, Georgia, Florida, Alabama, Mississippi, Loui- siana, and Texas into the state of California. This order prevents California growers from securing nursery stock or scions of new varieties in any of the above mentioned states. By special arrangement, hoAvever, the citrus seeds planted by nurserymen which come from Florida and Cuba are admitted, provided they are sent in care of some desig- nated agent of the Commission, who fumigates them be- fore delivery to consignee. Another quarantine order prevents the importation from Hawaii of mangoes, oranges, avocados, and other fruits which are hosts of the Mediterranean. fruit fly, Ceratitis capitata. Still another order forbids the shipment into California from Mexico of oranges, mangoes, or other fruits which are hosts of the Mexican orange maggot, Tripeta ludens. These latter, however, have now been superseded by national quarantine orders. It has long been the custom of the State Commissioner of Horticulture to hold two meetings each year which are known as State Fruit Growers' conventions. One meeting is usually held at some convenient place in the northern part of the state and the other in the southern part. The proceedings of these conventions are brought together, edited, publishetl, and distributed free by the State Com- missioner. The meethig hekl at Davis in June, 1914, was the fort>-fifth such convention. The printed proceed- ings of these conventions represent a very fertile source of information for the student of California citriculture. 110 Citrus Fruits THE COUNTY COMMISSIONERS OF HORTICULTURE The California State law providinjj: for County Horti- cultural Commissioners has been amended many times. The present law, approved March 25, 1911, provides: that whenever a petition, setting]: forth the legitimate need for a Commissioner and signed by twenty-five or more resident freeholders who are possessed of horticultural properties, is presented to the county board of sujjer- visors, said supervisors are requirerl to a])point a County Horticultural Commissioner from the list of eligibles, who must have passed the examinations held by the state board of horticultural examiners. The term of the County Commissioner is four years. Many. of the duties of the County Commissioner are pre- scribed by county ordinances, and these vary in the differ- ent counties. The Commissioner is usually required to keep informed as to the particular localities within the county where pest infestation is serious. He must have the orchards and ornamental plantings inspected, and when in his judgment the scale insects have increased in any orchard until they constitute a public nuisance, he must serve written notice on the owner to abate the nuisance by fumigating, spraying, or otherwise within a certain time limit. If this order is not complied with, the Commis- sioner may enter the premises and abate the nuisance, the cost of such work becoming a lien on the property. If the cost of the work is not paid, enough of the property may be sold at public auction to satisfy the lien. Such ordinances have been tested in the courts and Horticultural Inspection and Quarantine 111 found constitutional, the acts of the County Commissioners being upheld in each instance. County Commissioners may appoint k)cal inspectors in outlying towns and fruit districts within the county. The Commissioner also renders an annual report to the State Commissioner and a monthly report to the board of supervisors of his county. As special state quarantine officers it is the duty of the County Commissioners and their agents to inspect every shipment originating outside of the state, as well as those coming from other parts of the state which arrive in their territory. It is also the duty of the Commissioner to inspect every outgoing shipment of horticultural goods before it is ac- cepted by a common carrier. The law requires common carriers to accept only such packages or lots as bear a statement signed by the Commissioner or his agent certifying that the goods are free from injurious pests. We find, therefore, that every package of horticultural goods is inspected twice, once at the point of shipment and again at the place of delivery. THE NECESSITY FOR INSPECTION The question may arise in the mind of the reader as to whether this complex system of quarantine and inspection is worth while. The answer to this question may be found in the following quotation from California Experiment Station Bulletin No. 214, by H. J. Quayle. " That insect pests are one of the important factors m the citrus fruit industry of California is shown by the fact 112 Citrus Fruits that more than half a million dollars are expended annually hi their control. This amount includes only what is actu- ally ex})ende(l in fumigation and spraying, and does not take into consideration tlie loss of fruit from improperly treated trees or trees not treated at all. The cost of fumi- urangf trues bulled, ready for market. gation in one county alone amounts to -5200,000 annually. P\irthermore each county maintains a horticultural Com- missioner, and many of them a corps of inspectors, pri- marily on account of insect enemies, who are charged with the quarantine and inspection work, the cost of which in some of the counties may run as high as $25,000 annually. All of this vigilance seems to be warranted by thirty Horticultural Inspection and Quarantine 113 years' experience of the most important fruit section of the United States. " It has been estimated that the average cost of fumiga- tion per tree, taking the whole of the citrus belt, amounts to about 30 or 40 cents, which means an expense of approx- imately $30 to $40 per acre, and this is done on an average about every other year. This is intensive insect fighting, but when the improved market value of the fruit is con- sidered, it is money judiciously spent with such a valuable crop as the orange or lemon." In conclusion we may say that the benefits of exemption from scale insects is clearly reflected in the prices asked for land and bearing orchards in scale-free localities. The annual tax of 15 to 20 cents a tree for fumigation is especially unwelcome and growers in scale-free localities do well to exercise every possible precaution to prevent the introduction and establishment of such relentless tax-gatherers as the insect pests and plant diseases have proved themselves to be. CHAPTER VII IMPROVEMENT OF CITRUS TREES BY BREEDING The production of citrus fruits in California and Florida is increasing at a rapid rate. The shipments from these two states for the season 1913-14 reached a total of about sixty thousand cars. Thousands of acres of young orchards are just coming into bearing, and the near future will undoubtedly witness a large increase in produc- tion. The problem of how to make a profit in the business in spite of the heavy production will loom large in the future. Undoubtedly a great deal may be accomplished through the marketing organizations by securing better distribu- tion of the fruit and increased consumption through proper advertising. Yet it is a fact that much loss is at present due to a lack of varieties which are well suited to the cli- matic and soil conditions under which they are grown, to ignorance in regard to adaptation of varieties, and to sports or aberrant forms which occur throughout the citrus growing districts much more commonly than is generally recognizetl. Through carelessness or ignorance in the selection of bud-wood many poor or even worthless types have been 114 Improvement of Citrus Trees by Breeding 115 propagated and widely planted. The poor financial show- ing made by many orchards is due largely to the prepon- derance of trees belonging to aberrant forms. While some progress may be made toward improved varieties through hybridization, the waiter is strongly of the opinion that much better and quicker results are to be secured through the careful selection of desirable bud- sports which occur rather frequently on trees of the old standard varieties. HYBRIDIZATION The object of hybridization is to secure seedlings which combine the desirable characteristics of two or more parent trees. The flowers of the selected parent trees are cross- pollinated by hand, using great care in excluding foreign pollen. Cross-pollination is a very easy operation and may be performed successfully by any one willing to use a little care and perseverance. The structure of the citrus flower is very simple and a knowledge of the functions of the different parts is easily acquired by the study of the diagram at Fig. 14. The essential organs of the flower are the stamens and pistil. The anthers bear the pollen grains, each one of which when placed on the stigma will germinate and send a tube down through the style and into the ovary. The male nucleus from the pollen grain passes down through this tube and conies in contact with the female egg-cell of the ovule with which it fuses, thus bring- ing about fertilization and the combination of the charac- ters of the two parents. A separate pollen grain is needed 116 Citrm Fruits for each seed, and tlie parental characters may be com- bined in a different way in each case. After the ovaries have been fertilized they grow into viable seeds. It is not always necessary for citrus flowers to be pollinated and fertilized in order to produce fruit. The Navel orange for instance rarely contains seeds and on that account is knov,n as a parthenocarpic fruit. When cross-pollination is accurately performed, it is necessary to place paper bags over the blossoms which are to be used as a source of pollen, before the buds open. This is necessary in order to prevent the possibility of the mixing of pollen by insects. The pollen may be gathered and dried on papers and stored in small bottles for use, but it is often convenient to cut the twigs, bag and all, and carry them to the tree which is to be used as a female parent. Large buds just ready to open should be selected and all the smaller buds and open flowers on the twig removed. The petals are pried apart with a small pair of forceps and an anther bearing ripe pollen is taken from a blossom within one of the bags and placed firmly upon the stigma, pressing it down into the drop of white mucilage. If no mucilage appears on the stigma, it is evidence that the bud is immature. The camel's-hair brush commonly used in cross-pollinating fruits is not satisfactory in citrus work on account of the copious excretion of mucilage by the stigma. It is wise to cross- pollinate several buds on each twig, as many are apt to drop off. After the pollen has been placed on the stigma, the small immature anthers must be removed from the flower for fear that the pollen produced later by them may interfere with the results. In the case of the Navel orange Improvement of Citrus Trees by Breeding 117 this is not necessary, as the anthers do not produce pollen. After the operation has been completed a paper bag should be placed over the twig and tied with string. After two or three weeks the paper bags may be replaced by cheesecloth bags, which remain on till the fruit is picked for seed. The value of crosses or hybrids produced in this way cannot be determined for several vears, or until the trees Fig. 37. — Type of standard Washington Navel orange. have been reared to fruiting. By top-working buds taken from the young seedlings into old trees the fruit may be secured earlier. The improvement of citrus fruits by this method is very slow and the results uncertain. Moreover it is doubtful whether an entirely new variety of orange or lemon, how- ever good, could gain much recognition in California in the face of the popularity of the Xavel and ^^alencia oranges and the Eureka lemon. The history of the industry in California has shown a constant elimination of varieties 118 Citrus Fruits rather than the acquisition of new ones. The greatest field for hybridization work lies with the pomelos. There is at present no thoroughly satisfactory variety of ])omelo suited to the climatic and soil conditions of California. The feeling of the growers in regard to better varieties of oranges and lemons was clearly shown some years ago when E. J. Wickson sent out a circular letter to determine the most urgent needs along the line of citrus breeding. The response of the growers was significant. They re- plied that what was needed most was a Washington Navel which would color earlier ; a Navel which would hang on the tree like a Valencia; a Navel that would not split ; a Navel that would not puff ; and a Navel more hardy to frost. Some growers wanted a Valencia that would not turn green a second time, or a Valencia without seeds. The most expeditious way of securing the results desired by the growers is by selecting and propagating those sports from the varieties mentioned which approach most closely the desired types. Such bud variations occur quite fre- quently in citrus trees. They present a vast field for the work of improvement of types. VEGETATIVE MUTATIONS OR BUD-SPORTS Citrus trees, in common with other plants, are observed to vary in several ways. There are fluctuations or un- stable differences which come and go in response to the various complex stimuli produced by changing conditions of soil and climate, or, in other words, changes of food and environment. There are also sudden changes known as Improvement of Citrus Trees by Breeding 119 mutations which result in new forms that are stable and form the starting point of new strains or varieties. Fluctuations are of two kinds, regular and fortuitous. As an example of regular fluctuation we may cite certain influences of climate and soil which produce substantially ^ it.. \^H t^ik^ Fig. 38. — Washington Navel oranges showing fluctuations in the navel; such variations cannot be preserved by budding. the same effect upon every plant of the same variety. Navel oranges grown in the hot Imperial ^'alley are much redder in color than those grown within the influence of ocean fogs near the coast. Oranges grown on light sandy soil are of larger size than those grow^n on stiff' clay soil. Under the head of fortuitous variations mav be included 120 Citrus Fruits many of the common malforms and monstrosities such as double oranges, oranges with protruding navels, fingered lemons, and various other teratological curiosities which may be found in the cull-heaps near the {)acking-houses. IMutations occur as sporting branches which show a different combination of characters from the rest of the tree. The immediate cause of mutations is not at present understood. They originate during the division of some single cell in the vegetative tissue which results in daughter cells containing the same determiners for char- acters but segregated and recombined in such a way as to produce characters visibly different from those of the parent stock. Thus appear new characters which, from the standpoint of the man who is growing the fruit, may be either valuable, neutral, or objectionable. When a shoot arises from tissue which has been formed by mutating cells, the shoot represents a new variety or sport variety which may be propagated by the ordinary method of budding. Sometimes more or less reversion to the old type occurs in the young trees. The cause of this has been observed to be due to the mode of origin of the sporting shoot. If the shoot arises from within the area of mutating cells in such a way that only these cells are used in the forming bud, then the resulting shoot will be com- posed exclusively of new cells and the sport may be prop- agated true without reversion. If on the other hand the shoot arises on the edge of the area of new cells in such a way as to include both kinds of cells in its structure, then there arises a mixed branch or " sectorial chimera " which may be expected to constantly produce branches of various kinds. Some will be like the original plant, some like the Improvement of Citrus Trees by Breeding 121 new form, and some in turn will be mixed depending npon the kind of cells occnrring at the point where each bud has its origin. The " Nomadic Albinism " described by Savastano ' was probably a sectorial chimera. Fig. '■anzo ). — Variegated sporf. Note white areas Volckamer's " Hesperides," 1695. leaves. From Sectorial chimeras are not uncommonly met with in citrus trees. The writer has found excellent specimens in commercial orchards and some have been kept under » An. del. Stazione de Agrum. e. Fruit. Vol. 1, 1911, XXIX. 122 Citrus Fruits constant observation and study for five years. A Valen- cia orange tree in an orchard near Whittier was evidently propagated from a bud with mixed cells, for it still bears year after year on all its branches both typical Valencia oranges and a small, very rough, and worthless mutation. A twig here and there will produce typical Valencias, while Fig. 40. — A variegated sport of Valencia orange. Notice white margin of ' others will produce curious mLxed oranges having certain sectors of the fruits composed of mutant tissue. The owner of this tree endeavored to get rid of the worthless type by pruning it out, but mutant branches continually returned, and it requires frequent pruning to keep them suppressed. In this case the mutant tissue happens to occur irregularly scattered or mixed with the tissue of the Improvement of Citrus Trees by Breeding 123 original form. Such a mixture has been called a " hyper- chimera." ' Mutations often occur in the cells which begin the formation of the minute ovaries in the blossom buds. As the ovary grows in size the mutation appears as a sector of the fruit which differs in color, ripening season, or thick- ness of skin from the rest of the fruit. Such curious fruits have been called "spontaneous chimeras." These striped oranges and lemons are often found by the pickers, who usually incorrectly attribute the phenomena to the in- fluence of cross-pollination. When we consider that these mutations are always formed before pollination takes place, the inadequacy of the theory of pollen influence is evident. When mutation occurs at the base of the ovary it is not possible to continue it by propagation as no buds occur on the fruit. When, on the other hand, mutation occurs on the trunk or branches in a position where an adventi- tious bud may arise, then propagation is easy. As before stated, many mutations showing various types of fruit and different bearing habits have occurred in the orchards, and through ignorant and careless cutting of bud-wood many of the worthless forms have become widely disseminated and now make up a considerable proportion of the trees in our commercial orchards. A vital need at the present time is a careful study of indi- vidual trees by each grower, who should determine which trees, if any, belong to unprofitable types and top-work 1 H. Winkler, "Uber Propfbastarde und Pflanzliche Chi- maren," Ber. Deuts. Bot. Ges., 25: 568-576. E. Baur, "Propf- bastarde, Periklinalchimaren und Hyperchimaren, 'Woe. a7., 27: 603-605. 124 Citrus Fruits them to the most desirable tyi)es. In this way the aver- age cost of production may be greatly reduced. The great need for a stufly of the performance of individual citrus trees was emphasized by the writer in 1910.' Since then many such studies have been made, by far the most comprehensive of which are those of A. D. Shamel.^ Out of a mass of ma- terial the follow- ing condensed quotations have been selected from the studies of J. II. Norton/ formerly Super- intendent of the Citrus Experi- ment Station at Riverside : "The Navel orange grove FiG.41. — Sectorial chimera of Valencia orange. from which the following data are taken is located in West Highlands, San Bernardino County. The trees are the same age and the soil condi- 1 Coit, J. Eliot, "The Relation of Asexual or Bud-Mutation to the Decadence of California Citrus Orchards," Rpt. 37th Cahfornia Fruit Growers' Convention, 1910, p. 32. 2 Shamel, A. D., "A Study of the Improvement of Citrus Fruits through Bud Selection," U. S. Dept. of Agriculture, Bureau Plant Industry, Circular No. 77, 1911. 3 Norton, J. H., "Variations in the Productivity of Citrus Trees," California Cultivator, Vol. XL, No. 10, 1913. Improvement of Citrus Trees by Breeding 125 tions uniform. This grove contains 1525 trees planted 90 to the acre. The trees are about 16 years old and the grove is considered somewhat above the average in pro- ductiveness, yet the trees vary in yield from nothing to 426 pounds of fruit per tree. " The following is the annual expense of this grove per tree : " General care including taxes, water, pruning, and fumigating, $1.14 Interest on Investment, 1.11 Total annual expense per tree, .$2.25 "The fruit from this grove was sold for 1§ cents per pound on the tree. The trees that bore less than 150 pounds of fruit were maintained at a loss, while those yielding more than 150 pounds paid a profit. This is graphically shown in Figure 44. " The curved line represents the yield per tree in pounds arranged in the order of yield. The horizontal line AB is the * dead line,' and any tree the yield of which falls below this line was maintained at a loss. The shaded part of the curved line shows the trees that the owner realized no profits from. The shading above the line AB is due to the loss sustained by the trees recorded below the line. There were 490 trees or 32 per cent that yielded less than 150 pounds of fruit. This loss was made up by the profits from the next 646 trees, that is, the profit from 42 per cent of this grove was required to offset the loss sustained by 32 per cent. Seventy-four per cent of this grove therefore gave neither profit nor loss. This leaves 126 Citrus Fruits the net income to be derived from .389 trees, or 26 per cent of the grove. " The total yield of the gro\c ^vas 280,254,5 pounds of Fig. 42. — Orange showing ■^cttoiKil chimera. From Ferrarius, 1646. oranges which at l| cents a pound, gave a gross in- come of S4203.81. The expense was S3431.25, leaving a net income of $772.56 or an average net profit per tree of Improvevient of Citrus Trees by Breeding 127 51 cents. Could the loss clue to the 490 poor trees have been eliminated without increasing the production per tree, then the net profits from the remaining 1035 trees would have been S1125.96 or SI. 09 per tree as compared with 51 cents profit per tree which was actually the case." The record of this West Highlands orange grove may be considered fairly typical of a large proportion of the Fig. 43. — What is known as the "wrinkled sport" of Eureka lemon compared with normal fruit. Both from same tree. groves in California. The differences of yield noted were due both to fluctuations and mutations, but the extreme differences were undoubtedly due to mutations. The average yield would be greatly increased by top-working those of the 490 poor trees which proved to be mutative to buds carefully selected from the tree which yielded 426 pounds. Many of the most progressive growers now keep accurate performance records and top-work 128 Citrus Fruits the unprofitable trees as soon as they are discovered. In the case of the AustraUan and some other worthless mutations of Navel orange trees performance records are hardly necessary, as any experienced man should be able to recognize such poor types at a glance. For the segre- gation of trees which represent undesirable mutations, whose chief difference is that of yield, the i)erfomiance record is indispensable. There is no scientific evidence to warrant the belief that anything worth while may be gained by the selection and propagation of trees whose high yield is due to fluctua- tion. It is vital that the high yield be due to a true muta- tion in order that the type may be propagated and progress made. As a matter of fact, the standard type of Wash- ington Navel is normally a heavy bearer and the majority of mutations observed are retrogressive. It is chiefly to counteract retrogression that top-working is practiced. Occasionally, however, mutations of peculiar value appear. The Thomson and the Navelencia may be cited as exam- ples. It is not unlikely that a general increase in the amount of individual tree study by many growers may lead to the discovery of new mutations which may be of great value to the industry. For hhn who brings such mutations to light is awaiting both honor and financial reward. THE SELECTION OF BUD-WOOD The foregoing discussion emphasizes the fact that the selection of bud-wood is an exceedingly important matter, for if one does everything else in the most approved way "■■ ^^ ^" ~" 1 -^ 1 > r> -i L\ ^ ^\ "^ < \ \ \ \ \ , \ \ j( i.^ -7 \ \ \ s, consequently hut few growers would have water available at the critical tune. Those who pump their _ water do not as a >AtY- -- - . , . „;■ """v ./^^r— AvJ^fc^ rule h^ve pumps of sufficient ca- pacity to cover their entire acre- age at one time. Certain grow- ers at Riverside once made an ex- periment of heat- ing the irrigation water by passing it through a boiler. This was finally abandoned as too much heat was wasted through the smokestack. 0. By viixiug the air by creating artificial wind. — This has been ac- complished in California in two ways. By drawing a wagon about through the orchard bearing a huge rotary fan driven by a gas engine ; and by building large bonfires at certain points which create a slight draught. Both methods have been abandoned as inade- quate in the event of a sharp frost. Fig. 77. — Eichoff Coal Burner. Frost and Orchard Heating 249 7. By causing frozen, plants to thaw out slowly. — If all frosted fruit could be picked before it had thawed out and placed in storage where it could thaw gradually, a large proportion might be saved. Unfortunately, there is no Fig. 78. — Hamilton Down Draught. time to pick it, and there are no houses big enough to hold it. Some growers build fires of wet straw and manure on the windward side of the orchards and attempt to keep a blanket of smoke over the orchard all of the 250 Citrus Fruits morning succeeding the frost for the purpose of keeping the trees shaded and allowing them to thaw slowly. In some cases this has apparently been quite suc- cessful. 8. By the direct addition of heat to the ylants and the air surrounding them. — This has been accomplished by burn- ing wood fires in the orchards, by burning coal in wire baskets, by burning smudge fuel (shavings and tar), by suspending electric heaters in each tree, and by burning crude oil or low-grade distillate in some form of sheet iron receptacle. Coal is too scarce and expensive at ten dollars a ton when compared with oil at two cents a gallon. Smudge fuel is unsatisfactory on account of the smoke and the scarcity of the material. Electric heaters are clean and efficient but too expensive to install. There is not sufficient electric current available to heat more than an extremely small proportion of the orchards. Several experiments were carried on with small electric heaters hung in the trees of the National Orange Com- pany's Ranch in southern California during the winter of 1912-13. About one horse power of electric energy was used per tree during the cold period. A thermometer, the bulb of which was embedded in an orange on the exterior of a heated tree, showed a temperature T F. higher Fig. 79. — Bolton. Frost and Orchard Heating 251 Fig. 80. — Coe. than a similarly placed instrument on an unheated tree. The fruit on the inside of an unheated tree would prob- ably have shown a much higher temperature. In a letter from II. B. Chase, who conducted the experiments, it is stated that the tem- perature of the air in the orchard showed no appreciable increase, but the trees and fruit came through in much better shape than the trees which were not heated. The only conclusion to be drawn from this is that all of the heat given off by the electric heater is radiant heat which passes through the air without heating it and is absorbed by the limbs, foliage, and fruit. The great advantage of such a heater over the oil or coal heater at once becomes evident. With the electric heater the heat given off practically all gets to the place where it is needed, while with the other forms of heat generators which are placed in the rows be- tween the trees, the heat given off (largely convectional heat) is carried up above the trees to a great extent and therefore lost. Electric heating on a large scale is apparently out of Fig. 81. — Pomona Pipe-Line Heater. 252 Citrm Fruits the question because of tlie lack of sufficient current to serve the orchards as a whole. It would seem a pity, however, if a few conveniently located orchards might not be able to take advantage of idle dynamos during early morning hours when street cars and factories are not running. With the development of enormous quantities of very cheap oil in California, the oil burning orchard heater has })roved itself eminently practicable and is now almost universally used throughout the citrus districts. ORCHARD HEATING WITH OIL In the early nineties, when the oil production of southern California was rapidly increasing, Charles Froude intro- duced the first oil heater. This heater was later im- proved by J. P. Bolton of Fresno, California, formerly U. S. AYeather Bureau Observer at that place. The frosts of December, 1895, in southern California brought about a greatly increased interest in frost prevention devices. In this month the Riverside Horticultural Club in co- operation with the U. S. Weather Bureau, made a num- ber of tests of smudging devices, heaters, and vaporizers, and published the results of the experiments. It was decided then that coal burned in wire baskets, as described by Edward Copley,^ was the most satisfactory method. Since this time, however, on account of the tremendous development of oil wells in and near the citrus districts, oil as a fuel has become cheaper and more popular from year to year. ^ Riverside Press and Horticulturist, April, 189G. Fro.st (i)til Orrlidrd Ilnttiiuj 2oA Requiroiiciits of Orchanl llnitcrs The ideal oil heater should provide ji;o()d conihiistioii and be as nearly smoke free as possible. It should be substantial yet simple in construction and of anijjle capacity. The rate of combustion should be easily controlled and it is an advantage to have the parts nest well for storage. The covers must effectually prevent rainwater from entering. Ease of handling, filling, lighting, extinguishing, and efficiency of radiation are all important. The cost should be low, usually not above $1 each. The combustion should be good, not only to obtain as many heat units as possible from a given quantity of oil, but to lessen the amount of soot given off. The old idea of smudging was to give off as much smoke or smudge as possible in order to reduce loss of heat by radiation from the earth. While this may have been satisfactory to deciduous fruit growers when used at blossoming time, it is a positive detriment to bearing citrus orchards. The soot collects on the mature fruit and necessitates rather expensive special washing. While smoke in an orchard does conserve some heat, citrus growers would be glad to furnish a little more fuel to make up the loss by radiation if they could dispense with the soot-laden smoke. Most manufacturers ad- vertise smokeless heaters, but few of them as yet ap- proach smokelessness, and at the present time none of the cheaper oil burners are entirely satisfactory in this regard, although marked progress has been made toward this end. 254 Citnis Fruits Good combustion is also important when low grade oils carrying a large amount of asphaltum are used. Many heaters will not burn out clean with such oil. A cake of gummy material is left in the bottom of the heater which is very difficult to remove, and soon the capacity of the heater is much reduced. Heaters should be as simple as possible, for all classes of labor- ers will be required to operate them in the cold, dark nights. The less joints, valves, and attachments a heater has the better. Ample capacity is important. One gal- lon heaters have been largely discarded in favor of the three and five gallon sizes. The capacity should be suf- ficient for a heater to burn at least eight hours without refilling. If small heaters are used, a large number will be required, and this increases the labor of handling and operating. It is important that heaters be fitted with some device Fig. 82. — Dunn. Frost and Orchard Ileatim 255 for controlling the rate of combustion. This not only permits conservation of fuel, but adds a great element of safety inasmuch as the oil saved in the early part of the night may be sorely needed at some critical time in the early morning. Some heaters when burning low are apt to accumulate gas and explode, throwing oil over the trees and in- juring them and less- ening the safety of the operators. The heating equip- ment of citrus orchards remains in position all winter, which is the rainy season in Cali- fornia. If not well protected from rain, water will find its way into the oil and sink to the bottom. When the oil is lighted this water turns to steam and causes the heaters to boil over. This results in a temporary bonfire which soon burns out and leaves the trees unprotected. Fig. 83.— Canco. 256 Ciirus Fruits The f^reater the j)r()})()rti()n of radiated, and the less convectional lieat <:;iveii off by any heater the greater its efficiency. Tliis important principle is often JSl li__-jM overlooked whUe con- sidernig ponits appar- ently more practical. The Indians of Peru are said to have used for centuries, in pro- tecting their crops from " gravity " spring frosts, a heavy clay pot in which char- coal is burned. By this means they se- cured radiated heat almost exclusively. From a considera- tion of the above re- quirements it will be seen that the develop- ment of a thoroughly practical and efficient oil heater is not an easy matter. Four or five of the require- FiG. 84. — Rayo. ments may be combined without much difficulty, but some are more or less conflicting. It is especially diffi- cult to combine perfect combustion and control of combustion with simplicity and cheapness. Frost ami Orchard Heating 257 Types of Oil Heaters During the years 1911 to 1914 there was a tremendous amount of experimentation in developing types of heaters to meet the require- ments of citrus growers. Almost every one, from the local blacksmith to the Standard Oil Com- pany, seemed to have a new idea and was sure that he could pro- duce the attachment or device which would put him ahead of everybody else. As a result, a very large number of different heaters were turned out and the patent attorneys had their hands full. Still the improvement in heaters goes merrily on. We cannot under- take a detailed descrip- tion of all these different heaters, as lack of space forbids, and no doubt they will all be changed more or less during the next few years. The ac- companying sketches 8 Fig. 85. 258 Citrus Fruits Fig. 86. — Hamilton Reservoir. grouped into three general classes heaters ; (6) automatic reser- voir heaters; (c) pipe-line heaters. Simple reservoir heat- ers are the kind ordinarily used which burn from a free surface and are adapted to low-grade oil. Automatic reservoir lieat- ers have a patent burner sepa- rate and several feet distant from the tank. The high- grade oil used is fed by a small iron pipe which passes through the almost smokeless flame, the oil being volatilized as it is fed. The burner is inclosed in a sheet iron pipe or drum, which acts as a radi- ator. This type has great pos- sibilities, but is rather expen- sive and cumbersome. Pipe-line heaters are fed through set above the orchard. There are and pictures of heat- ers installed in or- chards will suffice to give a general idea of the leading types at this time. At present these heaters may be : (a) simple reservoir Troutnian. pipes from a large tank several forms, some of Frost and Orchard Heating 259 which burn the oil by dropping it slowly into a super- heated cast iron bowl. Others require the orchard to be piped with compressed air as well as oil, and the oil is finely atomized in the burner and driven with some force into the drum, where it burns. The great objection to these forms is the expense of piping the orchard, yet there is much in their favor. The rate of combustion of all the heaters in the orchard may be controlled by operating one valve at the tank, and much of the annual expense of handling and loss from deterioration of reservoir heaters is eliminated. Installation of Heaters The number of heaters required to the acre varies of course with the size and variety of trees and the degree of cold to be encountered. A fairly common equipment consists of one three gallon heater to a tree, which is usually about ninety to the acre. These should be reenforced by an extra row around the windward side of the orchard. With such an equip- ment it should be possible to raise the temperature from seven to ten degrees for from seven to ten hours, depending on wind and other factors. Some growers use double this number and light only every alternate heater during the early part of the night, 88. — Adamson Torch. 260 Citrm Fruits holding the others as a reserve to be Hghted only in case of emergency. It has been found much better to have many small fires than a few large ones, as large fires tend to create convectional currents which carry much of the heat far above the tops of the trees. There is also danger of in- juring the trees with large fires. As stated above, one heater per tree has been found to be the best plan. The heaters are placed on the ground midway between the trees and in line with the trees in one direction. If placed in the center of the square made by four trees, they will be in the way of the wagons which haul the fruit out and the oil and manure into the orchards. Properties of Fuel Oils Petroleum when first taken from the wells is rich in gases and lighter substances such as benzine, gasoline, and kerosene. Besides these, it also contains such basic sub- stances as asphaltum and paraffine. The crude oils of the Eastern states have chiefly a paraffine base, while nearly all Pacific Coast oils have an asphaltum base. The fuel oils on the market are residuals, the gasoline and other lighter oils for which there is a large demand having been removed in the refining process. What is known as crude oil is not petroleum as it comes from the wells, but a refinery residuum containing some of the heavy oils, a variable amount of asphaltum, together with some sul- fur and a little water. The types of oil commonly used are the so-called crude oil, smudge oil, slop distillate, and stove distillate. A Frost and Orchard Heating 261 particular -line five and one-half miles'lonj;, which serves ten smaller tanks each of 12,000 <]fallons capacity. At intervals through the orchard there are "gooseneck" stand pipes from which the wagons may be filled. The Limoneira orchard at Santa Paula is equipped with two steel tanks holding 210,000 gallons each and two cement cisterns holding 100,000 gallons each. This 5()0-acre orchard has five miles of 3- and 4-inch pipe-line and four miles of telephone line with a dozen or more telephones located in various parts of the orchard. Thirty-five tank wagons and trucks are used to distribute the oil to the heaters. Oil Heating Operations For delivery of oil to the heaters, tank w^agons of four or five hundred gallons capacity should be used. Heavier wagons are difficult to handle in cultivated or freshly irrigated soil. The tank is provided at the rear with a large valve or molasses gate, and men following the wagon fill the heaters by means of five-gallon buckets or ordi- nary oil cans with the tops cut off and provided with handles. Filling heaters by means of a trailing hose was tried, but has now been abandoned. One group of men go ahead of the tank wagon and remove the covers from the heaters, and others follow and replace the covers. Many kinds of lighting devices have been tried, but the Adamson lighter shown in Fig. 78 has come into almost universal use. This is merely an oil can in the spout of which a roll of wire gauze and asbestos wicking Frost and Orchard Heating 265 has been loosely fitted. After lighting the wick and in- verting the can over an open heater a few drops of gasoline or high-grade stove distillate will pass through the flame and fall burning into the heater. By use of this device heaters may be lighted almost instantly. It is a peculiar fact that new heaters are very difficult to light the first time. This difficulty is easily obviated by crowding a Fig. 92. — Placoinent of orchard heaters. Extra fuel undor trees. loose wad of tow or excelsior into the mouth of the down- draught tube or by hanging a small asbestos wick on the side. This precaution will usually not be necessary after a little soot has accumulated in the heater. It is the custom to begin firing lemons when the tem- perature at three feet from the ground reaches 30° F. A safe plan is to watch the young leaves on the lower part of the trees and begin firing as soon as they show transparent spots indicating that they are freezing. 266 Citrus Fruits Oranges may be allowed to go several degrees lower because they do not carry blossoms and tender young fruit in winter as the lemon does. It has been found that it is much easier to hold the tempera- ture at 32° than it is to raise it to 32° again once it has fallen lower. Many growers make a practice of lighting only every alternate pot at first, holding the others in reser\'e to be lighted later if needed. In case heavy firing and refilling becomes necessary it sometimes is confusing for the workmen to tell at a glance w'hich heaters were lighted first. This difficulty may be obviated by painting a ring with white paint on every alternate pot in the rows. It also saves about one-third of the labor of lighting alternate pots to work diagonally through the orchard when the trees are planted in squares. It often happens that the temperature will not go below 32 degrees before four or five o'clock in the morning, and Fig. 93. — The perforated stack gives good combustion but may admit rain- water. Frost and Orchard Heating 267 it will be necessary to fire only a few hours. This usually pays well, however, for the blossoms and young fruit which are on the trees during winter mature in late summer when the prices are highest. As soon as the sun rises or the wind begins to blow the temperature rises and the heaters may be extinguished and the oil conserved for future needs. Heaters may be extinguished by replacing the covers. Occasionally on very cold nights it may be necessary to refill the heater during firing operations. This is accom- plished by placing the cover on for a few moments until the fire is out and then refilling and relighting. During the winter 1912-13 one orchardist fired his lemon orchard on twenty-nine nights and saved enough fruit to pay for his heating equipment and all the expense of firing. Care of Heaters The depreciation of orchard heaters is heavy, especially with the cheaper forms. Being exposed to winter rains, they rust badly unless well cared for. It is usual to charge off from 15 to 25 per cent depreciation for each year of service. In the spring when danger of frost is past the heaters are emptied into the tank w^agons, the oil being returned to the storage tanks. Each heater is then dipped in asphaltum paint made by melting asphal- tum and diluting it with one gallon of stove distillate to ten pounds of asphaltum. Some growers even repaint the heaters in the orchard after a siege of firing has burned the paint off. It is extremely wasteful to store the heaters over summer in a rusty condition. In storing the 268 Citrus Fruits heaters it will be found that those whose parts nest well are much more economical of space. At present some grower^; store the oil-filled pots under the trees in order to save expense of handling. This is satisfactory pro- vided they are well i)ainted. One trouble has been chat careless laborers while hoeing under the trees are apt to strike the pots with hoes and cut small holes through which the oil leaks, soaking the soil and killing the trees. Cost of Oil Heating While the cost of heating varies widely and is in some cases high, there is no doubt in the minds of those who have the most experience that orchard heating pays well, especially for lemons. Two typical actual expense accounts are given below, one for a small grove and one for a large ranch. In both cases the figures are for 1912-13. Richardson Brothers' Lemon Orchard, Duarte, Cali- fornia. ^ Fourteen Acres — ^1000 Trees Equipment .500 Hamilton heaters, 3 gal $200.00 700 Bolton heaters, 2 gal 154.00 Tank wagon, 463 gal. capacity 48.00 Cement cistern, 8500 gal. capacity 125.00 Oil buckets 3, lighters 2 6.25 Four thermometers and automatic alarm .... 40.00 Total for equipment $573.25 Oil and labor Oil for 16 nights, 16,195 gallons $437.26 Labor bill for same 201.50 Total expense for operation $638.76 1 California Cultivator, Feb. 27, 1913, p. 260. Frost and Orchard Heating 2G9 LiMONEiRA Orchard Company, Santa Paula, California. Five Hundred Acres ^ 50,000 oil heaters (including a thousand of last year's pots) $50,000.00 2 steel storage tanks, capacity 210,000 gallons each 4,885.89 2 cement reservoirs, capacity 100,000 gallons each 3,000.00 5 miles of 3-inch and 4-inch pipe-Hne .... 6,375.03 35 tank wagons and trucks 4,315.00 150 spout pails for filling pots 300.00 200 torches 200.00 50 thermometers 150.00 4 miles of telephone system 750.00 350,000 gallons of oil in orchard at 2\ cents . . . 8,750.00 500,000 gallons of oil in storage at 2\ cents . . . 12, .500. 00 Total $91,225.92 Reduced to the basis of one acre, the investment is : 100 heaters $100.00 Storage space for 1,240 gallons of oil 15.77 Pipe-hne 12.75 One tank wagon to 14 acres — per acre .... 8.63 Pails — one to 3^ acres — per acre .60 Torches — one to 2^ acres — per acre .40 Thermometers — one to 10 acres — per acre . . .30 Telephone 1.50 Oil in heaters — 700 gallons at 2^ cents .... 17.50 Oil in storage — 100 gallons at 2^ cents .... 25.00 Total $182.45 Interest, deterioration, and maintenance : 6 per cent interest on total investment — - $10.94 15 per cent deterioration on $100 worth of heaters 15.00 6 per cent deterioration on other equipment . . 2.40 Estimated handling, painting, and filling (no firing) 5.00 Total $33.34 This outlay would seem at first glance to make the expense of growing lemons under such conditions pro- ' The Monthly Bulletin, California State Com. Hort., Vol. 3, No. 1, January, 1914. 270 Citrus Fruits hibitive, and yet J. D. Ciilbertson, the assistant manager of the ranch, states that all of this expense was met by the sale of the lemons saved and " fair interest in dividends was paid to stockliolders out of this year's earnings!" SEPARATION OF FROSTED FRUITS The Board of Food and Drug Inspection of the U. S. Department of Agriculture made the following ruling in regard to frosted citrus fruits on January 24, 1913 : " Citrus fruit is injured in flavor by freezing and soon becomes dry and unfit for food. The damage is evidenced at first by a more or less bitter flavor, followed by a marked decrease in sugar, and especially in acid content. Fruit which has been materially damaged by freezing is inferior and decomposed within the meaning of the Food and Drugs Act. " For the guidance of those engaged in shipping citrus fruit, it is announced that, pending further investigation, the following principles will be observed in enforcing the Food and Drugs Act : "Citrus fruit will be deemed adulterated within the meaning of the Food and Drugs Act if the contents of any package found in interstate commerce contain fifteen per cent or more of citrus fruit which, on a transverse section through the center, shows a marked drying in twenty per cent or more of the exposed pulp." There is much variation in the degree of frozen fruit on the same tree. The oranges on the tops of tall trees are usually less frozen than those near the ground. Fruit on the inside of the tree is less frozen than that on the out- Frost and Orchard Heating 271 side. Thus when the fruit is picked after a damaging freeze the good and bad fruit will be mixed together. If Fig. 94. — One type of water separator for frosted oranges. the grower does not want to sell all his fruit at a great discount as frozen fruit, or run the risk of having trouble 272 Citrus Fruits with Food and Drugs inspectors, lie must separate the frozen from the uninjured fruit. This is not as simple a matter as would at first appear for the reason that the fruit usually presents no outward indication of its interior condition. Usually, after a few weeks, frozen fruit loses a con- siderable proportion of its moisture and grows lighter in weight. Upon this fact are based all methods of separat- ing frozen from sound fruit. Normal oranges have a specific gravity of .82, but a few weeks after being frozen they dry out and become lighter. If oranges are dropped in a liquid the specific gravity of which is slightly lower than that of good fruit, the sound fruit will sink while the frozen fruit will float. The first separations made on this principle were ac- complished by using a mixture of kerosene and distillate oils. This proved very objectionable on account of the odor left on the fruit. D. C. Lefferts of Redlands in- vented a machine consisting of a large trough in which denatured alcohol of the proper specific gravity is placed to a depth of about thirty inches. The fruit is carried by conveyors and floated in the alcohol. A double con- veyor sweeps the surface of the liquid and delivers the frozen fruit to one belt, while the returning conveyor drags on the bottom and delivers the sound fruit at another point. More or less difficulty was encountered by the alcohol increasing in specific gravity by the water absorbed and the inability of redistilling it on account of national laws governing distillation. After the Left'erts machines had been used in many packing-houses for two years, Frank Chase of Riverside Frost and Orchard Heating 273 invented the water separator, which quickly displaced all other methods of separating oranges. This machine con- sists of an oblong tank through which water may be made to circulate at definite speeds by a small propeller. The oranges roll down an incline and drop into the moving water from a height of a foot or more. The light frosted oranges bob up to the surface quickly, while the sound, heavy fruit is slower to rise. IMeanwhile the oranges have been carried along by the current, the sound fruit passing under, and being caught by a horizontal wire screen, while the light fruit is carried along above it. At the farther end of the tank the two grades are lifted by conveyors and delivered to separate bins. By adjusting the position of the screen and the rate of flow of the water any degree of separation desired may be secured. This device enables the grower to save whatever sound fruit may have been left, and he may ship it under his regular brands with some assurance. The frosted fruit, if not seriously injured, may be shipped under a special frost brand or it may be used as a fertilizer, or made into various by-products. The water separator does not work satisfactorily with lemons for the reason that they are not round, and the depth to which they sink in the water will depend, to an extent, on the position in which they happen to strike the surface. For the separation of lemons the denatured alcohol bath is still used. A layer of lemons is placed in a large wire tray and submerged in the alcohol, which has 8 specific gravity of .82. The frosted lemons float and are removed by hand. Frequent tests with the hydrometer are necessary in order to keep the liquid at the proper density. T 274 Citrufi Fruits The question is often raised as to whether fruit whicli is only slightly frozen may not improve and fill up with juice again if left on the trees. The writer has observed this to take place to a limited extent both with lemoiLs and Valencia oranges. It appears that the individual juice vesicles in any particular fruit vary in their resist- ance to freezing. Some reabsorb the water which has been drawn out of the cells in order to crystallize, while others fail to do so and collapse. A juice vesicle once collapsed apparently will not fill up with juice again, although the cells making up the walls may retain life. Those juice vesicles which do regain their turgidity, how- ever, will grow larger than they otherwise would and to an extent will fill up the spaces left by the collapsed cells. When more than one-half the number of vesicles are de- stroyed, the gain in size of the others will hardly be suffi- cient to make the fruit marketable. See Fig. 72. COOPERATION IN FROST FIGHTING The large citrus ranches are in a measure sufficient unto themselves when frost fighting is undertaken. On account of their size and the large number of men employed they are able to organize their forces effectively. The interests of small growers, however, who own three, five, or ten acres each will be best served through cooperation wherever their holdings lie close together. For some years a very successful organization of this kind has operated at Pomona. It is known as the Pomona Valley Orchard Protection Association and is composed of many small growers of the district who own in the aggregate about Frovt and Orchard Hcatittg 275 3000 acres. Supplies are bought by wholesale, and the labor of firing is carried on by a specially organized force which is directed by one manager by telephone from a central station. Thermometer stations are located at convenient points along the roads running through the orchards, and scouts mounted on motor- cycles make the rounds of these sta- tions on nights when danger from frost is imminent. The tem- peratures are reported to the manager at the central office; and when the tempera- tures fall dangerously low in any section, the owners of the orchards in that district are notified by telephone to prepare for lighting their heaters. As these temperature rec- ords are all charted and preserved, they constitute a fund of information in regard to air currents and cold spots which is of very great practical value in all future operations. The example set by this organiza- tion should be followed in other districts where many small orchards lie near together. In concluding this chapter we may say that whatever Fig. 95. — Thermometer station of Pomonn Valley Orchard Protection Association. 276 CltrtLs Fruits may have been the final verdict in regard to deciduous orchard heating in intermountain states, the heating of citrus orchards in Cahfornia has proved a decided success, and new heaters are being installed as fast as the factories can turn them out. It is safe to say that citrus and especially lemon orchard heating in California has come to stay — at least as long as cheap fuel oil is available. Judging from the present increase in oil production in the state there would appear to be no warrant for any un- easiness in regard to the fuel supply for many years to come. CHAPTER XV PICKIXG AND PACKING ORANGES California oranges are harvested throughout the year. Navel oranges are picked from November 1 to May 1. Occasionally Navel picking continues till June. Most seedlings and miscellaneous varieties such as Mediter- ranean Sweet, Paper Rind St. INIichael, Ruby and jNIalta Blood, and Crafton are picked during May and early June. Valencias are harvested from June 1 to November 1 or later, thus o\erlapping the next Navel crop. Oranges are picked with a great deal of care for the reason that carelessness will result in bruises and abrasions of the skin which admit the germs of decay. An orange with a perfectly sound skin is proof against decay and will normally live and respire (breathe) for several months, gradually losing water and carbon dioxide until it finally dries up, turns brown, and becomes as hard as a wooden ball. Oranges will not rot unless they become infected with microscopic plants which grow in the tissue, softening and breaking it down. All such premature decays (and there are many kinds) are preventable. As before stated, the unbroken, healthy skin of the orange is proof against almost all such decays ; but when the skin is abraded in any way, these germs are almost sure to get in, as the air is full of them, and most ordinary 277 278 Citrus Fruits objects, such as gloves, bags, boxes, and the hke, are always coated with them. The reader should remember that these germs or spores are practically ever present, and he has only to blow his breath across a moldy orange or lemon and observe the billions of minute "seeds" or spores floating in a cloud, to realize the enormous number produced. If some of this "mold dust" be examined under a microscope, each particle will be found to be a well-developed spore capable of reproducing the same decay whenever it may fall in a suitable place to grow. Sometimes in dry weather a very slight scratch, which breaks the oil cells only, is cauterized over and healed without infection taking place, but this is not always the case and it rarely happens in damp weather. When the fruit is hanging on the tree the rind is filled with water and the surface cells are turgid. They are very easily broken when in this condition, while after the fruit has been stored in the packing-house a few days and the rind dried out somewhat the fruit will endure a great deal more in the way of rough handling. This is the reason why it is wise to let the fruit cure on the packing-house floor for a few days before running it through the various machines. The following are a few of the ways that abrasions may occur, and each of these should be carefully watched : a. Clipper-cutting ; careless pickers often allow the points of the clippers to extend beyond the stem and cut into or prick the skin. b. Stem punctures ; all stems must be cut oft' short and smooth, else they will be sure to puncture the skins of other oranges during handling. Picking and Packing Oranges 279 c. Fingernail scratches ; all pickers should be required to wear soft cotton gloves which are made especially for the purpose and sold for from 60 to 85 cents a dozen pairs. d. Gravel scratches ; sometimes a careless workman will throw an empty box from the distributing wagon in such a way that sand or gravel will be flirted into it. Before filling a field box it should always be inverted and the bottom tapped to dislodge any grain of sand present. e. Nails in boxes ; in many cases nails have been found protruding on the inside of field boxes, and their points rusted by pricking into perfectly good oranges. /. Thorn scratched and dropt fruit ; often with thorny varieties considerable care is needed to extricate interior fruit from the brush ^^^thout scratching it. No fruit which is dropped should be picked up, as it is almost sure to decav. Fiu. 96. — Tuttle fruit clippers with rounded point The clippers now used are a great improvement over the old styles. They have rounded points, and in certain types, cup-shaped blades. JMost fruit should be double clipped, that is, the fruit is separated from the branch 280 Citrus Fruits with one motion, and then held in a more convenient position while the stem is carefully cut off short and smooth. The green calyx or " button" should always be left on the fruit, for if it is pulled off, an opening is made for the entrance of decay germs. Only cloth picking bags are used, of which there are five or more types. They are car- ried by a broad strap which passes over the shoulder, and the most approved types are adjustable in capacity and open at the bottom, allowing the fruit to be emptied into the lug-boxes gently and without bruising. Many different types of lad- ders are used, the prevailing one having a third leg on hinges which is let down through the branches and rests on the ground near the base of the tree. Simple ladders which rest against the branches are not recommended, as they cause too much injury to the fine fruiting brush. Sometimes it is necessary to climb up into the crotches of the trees to reach inside fruit. This should be avoided as much as possible, as the heavy shoes of the pickers scar the bark and may carry the germs of gum-disease, especially when the surface of the soil is wet. Fig. 97. — Dashboard pick ing bag. Picking and Packing Oranges 281 Some growers designate one man in each picking gang to do what cHmbing is necessary and require that man to wear a grain sack tied about each shoe in order to avoid bruising the bark of the trees. In moving Ladders about great care should be taken to avoid injury to the fine fruiting brush which must be depended upon to bear succeeding crops. The fruit after being picked is transferred to the hig-boxes which are never filled quite full. These lug-boxes are then stacked one on top of the other on the shady side of the trees to await the spring wagon which conveys them to the packing- house. It is often customary to pick the fruit from the lower branches first, leaving the high fruit till later in the season. There are two reasons for this. One is that frost is often more severe near the ground, and low-hanging fruit picked early is out of the way of frosts. Secondly, the brown rot fungus grows in the soil, and during wet spells comes to the surface and fruits. The spores are splashed by the rains up on the low-hanging fruit, causing decay. It should be pointed out that this fungus is different in its action from most other fungi in not needing an abrasion for entrance into a sound fruit. The spores are motile, and when there is a film of rainwater on the surface of the fruit these spores are capable of Fig. 98. — Covina picking bag. 282 Citrus Fruits swimming into the stomates or natural breathing pores and causing decay. This finigus causes most trouble near the coast, and low-hanging fruit need not be picked early in the interior valleys on this account. Occasionally oranges are picked according to size on orders from the packing-house which desires a preponder- ance of large or small sizes as the case may be to meet the requirements of some certain market. Sometimes, also, in the case of a very heavy crop, it is advisable to thin the fruit on the trees rather than to pick it clean the first time. This is done to ease the strain on the branches and permit the props to be removed. It has been customary to pay pickers by the day rather than by the box. Piece work encourages careless handling and an increase in the amount of decay. The process known as " sweating, " by which the color of oranges is changed from green to yellow, is illegitimate when em- ployed for the purpose of deceiving the consumer as to the quality of the orange. Immature fruit may not be colored in the sweat-room and sold before it is fit to eat. There are cases, however, in which sweating is perfectly legitimate. Mature Valencia oranges often develop a green color during their second summer on the trees, and a light sweating to restore the former yellow color deceives no one, and is commonly practiced. -In some locations also the fruit becomes sweet before it is fully yellow. The coloring of such fruit may be finished Picking and Packing Oranges 283 in the sweat-room, providing always that such treatment is restricted to fruit which is otherwise mature and in good condition to eat. Very good prices are usually recei\ed for the earliest Fig. 100. — The Wis.s clipper now Li;iiig .^uperoeJed by the Tuttle shown in Pig. 96. Navel oranges sent to Eastern markets. This has resulted in recent years in considerable competition for the early markets and the shipment of much fruit which is im- mature and not satisfactory. Sometimes oranges are picked as early as the first week in October, while still perfectly green in color, colored by sweating and hurried to market. While some of this fruit brings high prices the result is disastrous for the much better fruit which follows. This unwise shipment of immature fruit re- sulted in so much loss and dissatisfac- tion among the growers of both Cali- fornia and Florida that the legislature of the state of Florida on June 13, 1913, passed an immature fruit law been enforced with some good results, the shipment of green fruit between September 1 and November 5 of each year which shows by test to Fig. 101. — Metal at- tachment for prop- ping limbs. which has since This law forbids 284 Citrus Fruits contain in the juice more than 1.3 per cent of acid. A simple and cheap method of making the acid test was worked out by the state chemist and placed at the disposal of all growers. Between September 1 and November 5 inspectors traveled through the state taking samples and making tests at the various packing-houses. Fig. 102. — Worm brushes used for polishing oranges. The simple field test was used, but in the case of dispute the remainder of the sample was sent to the state chem- ist for more accurate analj^sis. Some time before the Florida law was passed the Federal Board of Food and Drugs Inspection took notice of the artificial coloring of immature oranges by sweating, and made the following ruling : Picking and Packing Oranges FOOD INSPECTION DECISION 133 285 The Coloring of Green Citrus Fruits The attention of the Board of Food and Drug Inspection has been directed to the shipment in interstate commerce of green, immature citrus fruit, particuhirly oranges, which have been artificially colored by holding in a warm, moist atmosphere for a short period of time after removal from the tree. Evitlence is adduced showing that such oranges do not change in sugar or acid con- tent after removal from the tree. Evidence further shows that the same oranges re- maining on the tree increase markedly in sugar content and de- crease in acid content. Further, there is evidence to show that the consumption of such immature oranges, especially by children, is apt to be attended by serious disturbances of the digestive system. Under the Food and Drugs Act of June 30, 1906, an article of food is adulterated "if it be mixed, colored, powdered, coated, or stained in a manner whereby damage or inferi- ority is concealed." It is the opinion of the Board that oranges treated as mentioned above are colored in a manner whereby inferiority is concealed and are, therefore, adulter- ated. Fig. 103. — Rope feed hopper. 286 Citrus Fruits The Board recognizes the fact that certain varieties of oranges attain maturity as to size, sweetness, and acidity before the color changes from green to yellow, and this decision is not intended to interfere with the marketing of such oranges. H. W. Wiley, f. l. dunlap, Geo. p. McCabe, Board of Food and Drug Inspection. Approved : James Wilson, Secretary of Agriculture, Washington, D. C, March 28, 1911. The enforcement of this ruling has done a certain amount of good, but it has not entirely put a stop to the irresponsible shipment of worthless fruit, for the reason Picking and Packing Oranges 287 that it applies only to fruit which has been artificially colored.^ I w 1 4 SB H Fig. 105. — Box press and nailing maohino. ' Where there is li\ang vegetable tissue there is respiration, and carbon dioxide and water are given off. That the respiration of stored oranges takes place at the expense of sugar and acid and results in the gradual reduction in the amounts of these substances has been shown to be true by investigations carried on in the U. S. D. A. Bureau of Chemistry in 1905. " During the storage (of Navel oranges) there was a slight loss in acid and in sugar. This is confirmatory of similar results 288 Citrus Fruits Navel oranges color earlier and become sweet earlier in central than in sonthern or northern California. The apparent advantage in sweetness of early oranges from southern San Joaquin Valley is not due so much to an early increase in total sugars as it is to an early increase in the ratio between sugar and acid. Colby ^ has shown that it is the early decrease in acid, together with the early color- ing, which enables the growers in the San Joaquin \'alley to market their oranges early. Recently C. L. Alsberg, chief of the Bureau of Chemistry, U. S. D. A., suggested that as a result of in- vestigations carried on, the northern district oranges may be considered to be immature when the juice does not contain soluble solids equal to or in excess of eight parts to each part of acid present, acid to be calcu- FiG. 106.— Citrus fruit truck. with apples and peaches, and is probably due to the decomposi- tion of acid and sugar in the respiration of the fruit." . . . "The loss of acid and sugar noted above is to be explained, as in the case of apples, by the consumption of these substances as a result of respiration of the fruit." — W. D. Bigelow and H. C. Gore, "Ripening of Oranges." Read before A. A. A. S. in New Orleans, 1905. Contribution from the Bureau of Chemistry, U. S. Dept. Agr. — Published in Journal American Chemical Society, Vol. 29, No. 5, 1907. ^ G. E. Colby, "Comparative Examination of Shipping Navel Oranges from Northern, Middle, and Southern California," California Agr. Exp. Sta. RpL, 1898-1901, Part II, pp. 243- 251. Picking and Packing Oranges 289 lated as citric without water of crystallization. It was decided to base this figure upon the acid solids ratio in preference to the acid sugar ratio for the reason that the growers and packing-house foremen would be able to make the necessary analyses, which would be impossible in the case of sugars. Since this valuable suggestion was made growers and shippers throughout the early districts have applied the test quite generally and are cooperating in limiting ship- ments to fruit which shows the 8-1 ratio. The effect of this has been very beneficial as shown by market reports. Shippers of oranges will do well not to pick the fruit until it is in condition to be enjoyed on the tables of the growers themselves. If the orange industry in northern Fig- 107. - Packing stand. California is to grow to great proportions, it must do so on a basis of satisfactory fruit. Every orange sent to market should stimulate in the buyer a desire for more of the same kind. The siceat-rooni. — The sweat-room is an air-tight, fire- proof chamber usually built separate from the main part of the packing-house. Beneath a false floor are placed kerosene burning stoves of a type which does not give complete combustion. The hot gases and water vapor pass up through the floor and envelop the fruit. The temperature is controlled by ventilators in the roof and is u 290 Citrus Fruits kept for oranges at 100° F. for from three to five days, or until the oranges are properly colored. During this time the air in the sweat-room should be kept quite moist to prevent wilting and shri\'eling of the fruit. This will require close watching, as the air will dry out with some lots of fruit and tend to remain saturated B with other lots. Pans of water may be M set on the stoves, and occasionally it is « necessary to wet down the fruit and M the sides and floor of the room in addi- ■ tion. The fruit should be graded ac- ■ cording to shade of color, the lightest ■ being placed next the door, so that it M may be removed earlier than the rest if ■ desirable. The air should be a little ■ less than saturated with moisture. ^ I When the coloring of citrus fruit is ^^11^^ forced too rapidly the buttons (stems) ^^P^^B^^ shrink away and drop off. This is very ^^^^^Wj undesirable, as fruit without buttons is " not supposed to keep as well and is dis- FiG. 108. — Box counted in the markets. When used to ?ze^^^^ ^"^'^ excess the same gases which color the fruit throw the buttons. In very few places in California does the fruit come to the packing-house sufficiently clean to pack. In interior valleys it is covered with a layer of dust, and near the coast it is apt to show scale insects or the black smut (Meliola camellia) which is a fungous growth on the honey dew or excretions of scale insects. If fruit is simply dusty, it is run through a series of rapidly revolving dry roller Picking and Packing Oranges 291 brushes. In some cases it may have a spray of water directed upon it while in the brushes or it may pass in water between two series of submerged brushes. In the latter case a tank is necessary, and it is good policy to disinfect the wash water against brown rot infection. Wash water for oranges is usually disinfected by the Fig. 109. — Car squeeze. Large size. addition of one pound of permanganate of potash to 1000 gallons of w^ater in the morning, and at noon 2 pound is added to the same water. The water in the tank is changed each day. After being washed the fruit is conveyed by belts to drying racks in the open or under cover, or is run through an air-blast dryer. The fruit next passes on belts or roller ways before the 292 Citrm Fruits graders who, considering color, shape, smoothness, and blemishes, sort the salable fruit into three grades, stand- ard, choice, and fancy, placing each grade on a separate belt which conveys it to its respective automatic weighing machine where the proper proportion of each grade is credited to the grower. After the oranges pass the weigh- ing machines their identity is merged in the general pool of the house. The fruit next passes through the sizing machines, of which there are a great many different types, and each size is delivered to a separate bin. The bins are carefully padded on bottom and sides with cotton cloth, and have movable sides which provide for adjustment of capacity. Box shooks are usually bought in Oregon or northern California, and the boxes are made in the basement of the packing-house. They are made either by hand or by an automatic box making machine. A standard box of California oranges is 12 by 12 by 26 inches outside measurement. It is divided in the middle by a partition. For purposes of computing freight charges it is estimated to weigh when packed 72 pounds. On the end of each box is pasted a paper label, usually a five-color lithograph, showing some picture appropriate to the brand. Each packing-house or association has a series of brands copyrighted for its own use. In addition to this the finest quality fruit sold through the Cali- fornia Fruit Growers' Exchange bears the additional "Sunkist" label of the Exchange. The variety and size of the fruit and the packer's number is stenciled on the end of each box. Boxes which are liable to be sold in Picking and Packing Oranges 293 New York State are now stenciled with the exact dimen- sions and cubical contents of the box. Box shooks are made of Pacific Coast pine exclusively. The standard 8 slat orange box requires SiVff feet of lumber and costs about ISl cents delivered. The standard lemon box contains j foot more lumber and costs on an average 15| cents. The cheaper grades of tissue wrap- pers come from mills in Oregon and California, while the fine grades come from Hamburg, N. J. The paper is printed in Los Angeles from wide rolls on cylinder presses. The cost printed and delivered to the packing-houses for the 10X10, an average size, is about $17.50 a hundred thousand. A pound contains about 414 sheets. Box labels are procured from lithograph houses and are usually done in five colors. They cost about $3.00 per thousand. Special cement coated nails are used which cost in large lots about three cents a pound. INIetal box strapping comes from New Jersey chiefly in 6500 foot reels and costs about $1.46 a thousand feet. From 18 to 24 inches of strapping is used on each box. Most of the larger packing- houses use beveling machines for the ends and partitions and box making machines for putting the boxes together. Both women and men are employed as packers, women being most largely used. The empty box is placed on a packing stand which rests on rollers and has a revolving top. The hod holding tissue wrapping paper is placed over one end of the box. The packers stand beside the sizing bins, and wrapping each fruit in printed absorbent tissue paper, place it in the box with great dexterity and skill, averaging about sixty boxes a day. The fruit is placed in the box in its respective order of arrangement 294 Citrus Fruits Picking and Packing Oranges 295 according to the size. Each size of fruit has its own order of arrangement and the size is designated in the house and on the market not by the diameter of each orange, but by the number required to fill a box.' Oranges Size Average Diameter in Inches 64 3 = 80 3i 96 3f 112 S\ 126 3i 150 3 176 2| 200 2| 216 2f 250 21 288 2f 324 2\ 360 2i A very high pack is customary, and after the covers are forced on and nailed the boxes are usually delivered by automatic carrier to the car or precooling room. One hundred field boxes will usually pack out about sixty packed boxes. The cars vary in capacity, depending on whether they are provided with collapsible ice bunkers. The standard car of oranges contains 3S-i boxes loaded two tiers on end and six rows wide and including sizes 96, 112, and 250, and not over 20 per cent of the 126 size. The remainder of the car may be divided among the 150, 176, and 216 sizes. Cars other than standard are discounted from 25 to 50 cents a box on the market according to the number of off sizes they contain. ^ For further rules governing packing, see Chapter VIII. 296 Citrii.s Fruits The boxes are set with two inch air spaees running lengthways the ear. Each tier of boxes is braced in position by a narrow strip running across the car and Fig. 111. — Oraiij^c pttekt-rs at work. nailed to each box. As the tiers are set the slack through- out the car is taken up by a device known as a " car squeeze." A copy of the manifest card showing the num- Picking and Packing Oranges 297 ber of different sizes and their location in the car is tacked on the inside wall near the door. The freight is figured on an estimated weight of 72 lb. to the box, and is $1.15 a hundred pounds to points on the Missouri River and eastward. Icing charges are extra. Precooling The term " precooling " properly applied relates to the reduction in the temperature of any given lot of fruit before it is dispatched on its journey to market, in contradistinc- tion to the usual method of reducing the temperature gradually in transit. It has been found by experiment that when warm fruit is loaded into cars with ice and started on its journey across the desert that before the fruit in the center of the boxes is thoroughly chilled, decay has set in. This decay is checked, but on unloading the fruit in the warm, humid climate of the East such decay spreads rapidly. With precooled fruit the decay has not been allowed to become so much advanced, and ears do not require such frequent re-icing. Precooling will not take the place of careful handling. Inasmuch as citrus fruits, when carefully handled, keep excellently for long periods at ordinary temperatures, precooling is not as valuable with them as it is with other more tender and quickly perishable fruits. Several packing associations have adopted the practice of sending their fruit to market " under ventilation " or without ice, but it requires great care in picking, handling, and packing to be able to do this successfully. The large precooling plants which chill a whole train 298 Citrus Fruits load of thirty cars simultaneously by driving or circulating a blast of cold air through the cars, are owned by the rail- road companies who desire that precooling be considered a function of the transportation companies. Some packing associations which had built small precooling plants of their own objected to the above point of view and fought their case in the courts for several years, finally winning their point before the U. S. Supreme Court in January, 1914. The Court ruled that S7.50, for each re- icing, the rate set by the Interstate Commerce Commission, was reasonable and applicable to precooled shipments. The rate previously charged by the railroads for icing cars was $62.50 for the trip, regardless of whether much or little ice was needed. Inasmuch as precooled cars only require a comparatively small amount of ice en route, the saving to the growers by this decision amounts to about $30 a car. About 55 per cent of the oranges shipped East go forward under ice. In very cold weather and especially for cars sent to the extreme North, it is advisable, before loading, to paper the inside of the car with several thicknesses of heavy building paper to prevent the fruit from being frozen en route. The average haul for cars shipped east of the JNIississippi River is 2585 miles and the average time between San Bernardino, where the Santa Fe overland citrus trains are made up, or Colton, where the Southern Pacific trains are made up, and New York is about fourteen days. After many years of effort the citrus growers have gained from the railroads the right of diversion, which means that a car of oranges may be billed to Chicago, for in- stance, and when it arrives should the Chicago market Picking and Packing Oranges 299 be unfavorable it may be diverted to Cleveland or Buffalo or Boston or to any other place toward the East and within that traffic zone without additional char^^^■^^^^^'^■^'.^^■^'.'-■-■-^'^T- ^1 ^ Picking and Parking Oranges 301 to the car. The fire hazard is high and losses are rather frequent. Most of the houses belong to a local mutual insurance association which prorates and assures the losses as they occur. There are at present about 200 packing-houses in active operation in ("alifornia, besides a large number of sheds and old houses which operate only at infrequent intervals. The capacity of the houses varies from one to twenty cars a day. The associations which are affiliated with the Exchange enjoy the privilege of buying ranch and packing-house supplies through the Fruit Growers' Supply Co. This is a non-profit cooperative organization through which the growers pool their orders at low cost. The Sup- ply Company has an authorized capital of one million dollars and in 1914 did a business of $3,319,062.04 at an operating expense to the members of f of one cent on each dollar of business transacted. CHAPTER XVI PICKING AXD PACKING LEMONS The picking and packing of lemons differs radically from that of oranges as described in the previous chapter. Lemons are usu- ally picked from ten to twelve times a year, the heaviest pickings coming in ^Nlarch and April and the lightest in August and Sep- tember. It is a peculiar and un- fortunate fact that the heavy pickings come at a time of year when there is lit- tle demand for lemons and the Hghtest pickings come during the picnic and lemonade season, 302 Picking and Packing Lemons 303 when the demand is greatest. For this reason the proper storage of spring lemons becomes one of the important functions of the lemon packing-house. The following typical example of an actual yield of a 9j acre mature lemon orchard of mixed Eurekas and Lisbons growhig near Covina, Los Angeles County, gives a good comparison of the various pickings : Record of Lemon Pickings. Season 1910-11 Orchard of Mr. N. D. Mussey Pool Date Lug-boxes Pounds 1 Sept. 19 76 3,698 2 Oct. 19 60 2,880 3 Nov. 17 289 13,852 4 Jan. 3 520 24,470 5 Feb. 1 832 39,415 6 Alfir. 18 1,122 50,906 7 May 3 1,120 51,350 8 May 30 196 9,268 9 July 21 298 14,224 10 Aug. 30 52 2,506 Total 4,565 212,569 The method of picking lemons from the trees is much the same as with oranges except that the use of the ring and consequent searching about in the foliage among fruit of all sizes makes picking slower and more expensive. Es- pecial care should be used to prevent dead twigs and other trash from falling into the picking sacks as the weight of 304 Citrufi Fndis the lemons against such objects in handling will cause scratches in the skin. In some sections special picking sacks with closed tops are used to ])revent this. In this type of sack the fruit is introduced at the side near the top. For hauling to the packing-house the growers generally use a factory-made wooden wagon with steel skeins Fig. 115. — Two-story lemon packing house, Glendora, California. on which they place a wide flat rack usually about 8 feet wide and 14 feet long. The racks are made locally and are set on the gears over bolster springs. It is not un- common to see a string of three or more of these wagons hooked together and being drawn by the gas tractor which is used for cultivating the orchards. Lemons differ from oranges also in being valued for their acid rather than for their sugar content. A green Picking and Packing Lemons 305 lemon therefore is better than a yellow " tree ripe " one provided it is fully sized and mature. For these reasons lemons are picked altogether according to size rather than color. The pickers carry wire rings which are slipj)ed over each lemon, and every fruit which fails to pass through the ring is picked. In summer aring2| inches in diameter, inside measurement, is used ; while in winter and spring a ring one-sixteenth of an inch larger is used, inasmuch as the fruit will be held longer and will undergo greater shrinkage. On account of the demands of the markets mentioned above, there is a tendency to pick often in summer, care- fully searching for every lemon which may be up to size. This fruit is quickly colored in the sweat-room and hurried to market while prices are high. SWEATING AUTUMN LEMONS The sweathig of lemons is for the purpose of quickly changing the green color to a whitish yellow. While the practice of sweating oranges is sometimes abused, lemon sweating is always legitimate as it in no way de- ceives the buyer. In fact the mature but green lemon properly colored in the sweat-room antl hurried to market is usually sourer, and therefore better, than the lemon which lias been kept in storage for several months and has consumed a small portion of the acid in the process of respiration. For best results, lemons should be fired intermittently. The air of the sweat-room should be kept saturated with moisture, and beads of water should be in evidence on X 306 Citru.s- Fruits the ceiling at all times. If the air is allowed to become dry, the lemons will quickly shrivel. The temperature should be kept at 90° F. or ten degrees lower than for oranges. So far it has been impossible to fully color green lemons in five days and retain the buttons, as the same quality of the gas mixture which changes the color causes the buttons to drop off. Inasmuch as sweated lem- ons are sold and consumed quickly, the loss of the buttons is not as serious a matter as would otherwise be the case. STORAGE OF WINTER LEMONS In the late winter and spring when it becomes advisable to hold the fruit for summer markets, the problem of the lemon packer is very different from that of early fall. Instead of sweating the fruit and thus accelerating the life processes as much as possible, he now wishes to retard to the greatest possible degree these same life processes. The fruit is therefore picked with very great care in order to prevent abrasions. On arriving at the packing-house the lemons are carefully washed in a brush washer. For disinfection against brown rot, one pound of bluestone is added to each 1000 gallons of wash water in the morning and one-half pound added to the same water at noon, the water being changed each morning. To prevent the bluestone from corroding metal tanks it is well to apply a thick coat of asphaltum paint to the inside of the tank. The lemons are now separated into three grades accord- ing to color alone, known as green, silver, and tree-ripe ; the silver being those fruits which are just beginning to lose the deep green color. Each of these grades is placed Picking and Parking Lemons 307 loosely ill packing boxes and stacked uj), a car in each stack, on the storage floor. Lemons are often kept in this way six or even eight months, but the fruit picked after April 1 is much shorter lived than that picked earlier. Lemons picked green will keep much longer than those allowed to turn yellow on the tree. These tree-ripes are kept separate and shipped first. Lemons will also keep much better near the coast than in the in- terior valleys, where much more expensive storage houses must be provided in order to control the humidity. The great problem is to give plenty of ventilation in damp weather in order to prevent decay and to reduce the Fig. 11 1 washing machine and sort- ing table. 308 Citrm Fruits ventilation, or withhold it entirely in warm dry weather to prevent the fruit from losing moisture and shrivel- ing. The relative humidity of the air in the storage house should be held as near 80 per cent as possible, but this is very difficult to accomplish in interior valleys, where the humidity of the air varies from 90 per cent to as low as 10 per cent. In order to control the temperature and humidity each carload stack of lemons is inclosed in a heavy duck tent. These tents are usually made of 8 oz. special army duck, and are 10' wide, 10' high, and 20' long. This size includes one carload of lemons. This tent is open at the bottom, and is open at the four corners, which are laced so that any part of the fruit may have ventila- tion, without interfering with fruit that it is not necessary to ventilate. These tents are also built in other sizes, which is sometimes necessary to fit the space in a packing- house, but this is the size that is most generally used. The tent is hung from the ceiling on a frame, there being eyelets in the top to fasten to frame. In some of the packing-houses in interior districts the tents have been abandoned and the fruit is stored in large basements, usually built of concrete, with outside shutters which provide for ventilation. Unless the lemons have been very carefully handled from the orchard to the packing-house, a great deal of decay is almost sure to develop in storage. Lemons are always handled more carefully than oranges and the brush washer is about the only piece of machinery they are allowed to pass through. On account of the absence of machinery, a lemon packing house presents a very different aspect from an orange packing house. Picking and Packing Lemons 309 When the fruit is taken from storage it is graded by hand into fancy, choice, and standard, each grade being placed one layer deep in broad flat trays. Stacks of these trays of fruit are weighed and the proportion of the differ- ent grades credited to the grower of the fruit. All through washing, storing, and grading each grower's fruit is accom- panied by a ticket attached to the guide box. When each Fig. 117. — Lemon curing tents in p:u'king-housi of several hundred growers has four or five pickings in greens, silvers, and tree-ripes, all in storage at one time, the task of keeping account of each lot of fruit necessitates a well-organized system. In the packing-house lemon varieties are not kept separate, and the name of the variety is not stenciled on the end of the box as is customary with oranges. Lemon packers use the same packing stand that is 310 Citrus Fruits used for oranges, but instead of packing from bins contain- ing fruit all of one size, they pack from the trays, sizing the fruit by eye and hand, the range of sizes in each grade running from 210 to 540 per box. Lemons sizing 300 to 360 to the box are in greatest demand on the markets, Southern markets preferring the smaller and Northern the larger sizes. In one or two of the newer lemon packing houses, sizing machines built especially for lemons have Fig. 118. — Truck for handling stacks of lemon trays. been installed. These are operated very slowly in order to avoid injury to the fruit. Most packers still regard sizing machines for lemons with suspicion. The standard lemon box has an outside measurement of 11 by 14-2" by 27 inches and is divided in the center by a partition. For the computation of freight charges a box of lemons is estimated to weigh 84 poiuids. The standard car of lemons contains 312 boxes. Picking and Packing Lemons 311 Fig. ll'J. — Flicking lemons from sorting trays. 312 Citrus Fruits Lemons Size Average Diam- eter IN Inches 210 23 240 2| 270 2i 300 2| 360 2i 420 2i 490 2 540 U Lemons were formerly shipped under ventilation from November to March, and under ice the remainder of the year. Some shippers who have learned to handle their fruit with extreme care have abandoned ice altogether to their great profit. In 1912-13 only 14 per cent of the lemons shipped were iced. The average haul to market is 2283 miles, being 304 miles less than the average haul for oranges. This difference is accounted for by the fact that a larger proportion of California lemons are marketed west of the Missouri River, thus avoiding, to a certain extent, the sharp competition with Italian lemons through- out the Atlantic seaboard. The freight rate on lemons from California to New York, Chicago, and intermediate points has been fixed at $1.00 per hundredweight after a long and expensive contest in the courts, the lemon growers finally winning their con- tention. PICKING POMELOS AND TANGERINES Pomelos are picked from the middle of December to the following August and many growers keep some fruit for home use on the trees the year round. The total ship- Picking and Packing Lemons 313 ment of pomelos from California is not large, being ahont 200 cars per year. Ordinarily the fruit is stored in lug- boxes for a few days until the rind becomes soft and pliable. After this the fruit is packed in orange boxes and handled like oranges. Pomelos improve somewhat in flavor with storage and proper curing, and for best results, this fruit should be very carefully picked in February or March and held in storage precisely as are lemons until Mav, June, and July. Pomelos Size Average Diam- eter IN Inches 04 3| 80 3§ 96 3f 126 31 150 3 Large quantities of pomelos are grown in Florida, Cuba, Porto Rico, and the Isle of Pines, and these dominate the markets of the eastern United States. California pomelos are marketed mostly within the state and to some extent in the intermountain country and the Pacific Northwest. Only a few are sold in New York. On account of the state quarantine. Eastern pomelos cannot be brought into California for sale. At present a large portion of the California pomelos found on the markets are poor in quality. This is due to the fact that but little attention has been paid to pomelos and most growers tend to treat them in every respect like oranges. That the climatic and soil conditions in some parts of California are well suited for the production of a first-class pomelo 314 Citrus Fruits is evidenced by the fact that a few skillful growers market their fruit in New York at very remunerative prices in competition with Eastern fruit. Tangerines are the only variety of mandarin orange grown to any extent in California. They are picked, packed, and shipped in much the same fashion as oranges except that, being a fancy fruit and in limited demand, they are not shipped in car lots. It is customary to market tangerines gradually, including a dozen boxes or half-boxes in a car of oranges. ^&-^c/^- 7=2ai-y//vZ7 //o- D- -c Xx>^ ^rt A \ HHHHtHMHHHHHk i 1 i i ^^t:cLvy/y^^ Fig. 120. — Lemon packing house. Compare with Fig. 113. PACKING-HOUSES There are hardly two packing-houses in California which have the same capacity, arrangement, or equipment. In general the orange house is small and is equipped with a Picking and Packing Lemons 315 great deal of machinery, while the lemon honse is large and contains but little machinery. The fruit is received at one end from wagon scales and moves gradually through the house as it is washed, graded, sized, packed, and so on, until the packed boxes are loaded on the cars at the oppo- site end. Various types of mechanical conveyors are em- ployed to save labor in handlingthe fruit and packed boxes. ^^^iwN' ^^' JOiiMSTOlFBOITCO. Fu. IJl — Is, 1. J Cleanliness is very important. No decaying fruit should be allowed in the house, as the spores given off tend to increase the amount of decay. All culls should be conveyed by belt from the grading table to some bin or outhouse entirely separate from the main packing- house and situated to leeward of it. 316 Citrus Fruits The comfort of employees should be provided for by rest rooms and lunch rooms. The main packing floor should be well lighted by glass skylights, for it has been found that the efficiency, comfort, and spirit of the em- ployees are greatly improved by clean, airy, and well lighted work-rooms. Fig. 122. — Combination box label. Some packing associations confine their work to packing and shipping, while others take charge of all picking, pruning, and in some cases fumigating of the groves. In packing lemons, especially, it is a good plan for the packing-house manager to control the picking. The San Dimas Lemon Association, for instance, keeps account of the fruit picked by each crew of pickers, and as this Pick'nuj (iitd Pavkinij Loiwius 317 fruit comes out of storage and is sorted o\er a careful account is kept of the percentage of each kind of decay. In this way a check is kept on the pickers, and if decay due to careless handling occurs it may be traced back and the blame placed where it belongs. Each foreman of a picking crew knowing that he is responsible for any decay which may develop in his lemons takes pains to instruct his men in the best methods of handling the fruit. At the end of each season a substantial prize is awarded the j)icking crew in whose fruit the least amount of decay has developed. Pickers are drawn from many nationalities. Americans receive about $2 a day, while Japanese and Hindus are paid twenty cents an hour. A responsible picking foreman of considerable experience in handling lemons and men may recei\e $75 or more a month aside from a variable bonus at the end of the season. CHAPTER XVII BLEMISHES OF THE FRUIT AND THEIR PREVENTION A LARGE increase in the production of citrus fruits will mean, if it means anything, a keener competition in the markets. In order to meet this increased competi- tion, California growers and packers are being encouraged to adopt higher ideals in grading and packing. With more rigid grading the cull-heaps near many of the packing-houses assume large proportions. A conserva- tive estimate places the direct loss from cull oranges alone, aside from frozen fruit, in excess of a half-million dollars a year. It is well worth while, therefore, to make a study of the cull-heap, classifying and determining the relative im- portance of the various blemishes which cause oranges to be thrown into a lower grade or into the cull-heap. We will also consider how far it is practicable and by what means the proportion of culls to packed fruit may be reduced. The blemishes of citrus fruits may be classified according to their causes. For convenience we may group them under four heads, namely : insect, fungus, mechanical, and physiological blemishes. 318 Blemishes of the Fruit and their Prevention 319 As a result of counts of Navel culls made in twelve packing-houses during January and February, 1910 and 1911, it appears that on the average, the most prolific causes of culls are as follows, according to their impor- tance : splits, bruises, thorn stabs, thrips scars, sunburns, and worm holes. These six kinds of blemishes are re- sponsible for upwards of seventy-five per cent of the culls. These counts, however, did not take into consid- eration the brown spot which usually does not develop until the fruit has left the packing-house. INSECT BLEMISHES Insect pests and their control will be discussed rather fully in Chapter XXII and it is only necessary here to name those blemishes of the fruit which are due to insects. They are : thrips scars ; tortrix worm holes ; scale insects such as red, yellow, purple, and the sooty mold which follows and grows upon the excretions of the black, gray, and brown scales ; mealy bugs ; red spiders ; silver mites ; grasshoppers ; katydids ; and some others. The presence of a few scale insects on fruit intended for some markets in the East need not condemn it, but there are other markets, such as certain ones in British Columbia, where inspectors condemn all scaly fruit even though citrus fruits be not grown in the region. FUNGUS BLEMISHES The fungi which produce injury to the fruit are : brown rot, Pythiacysiis citrophthora; blue mold, Penicillium, 320 Citrus Fruits italicum; green mold, PeniriUinm digitatnm; gray mold, Botrytis cinerea; sooty mold, Meliola cameUicF ; cottony mold, Sclcrotinia libertifuia ; gray scurf, fungus not as yet identified; wither-tip, CoIIctotrichum gloeosporioides; black rot of the Navel, AUernaria citri; and stem-end spot, Cladosporium sj). (secondary). Most of the fungus diseases which cause blemishes on the fruit result in complete loss. The nature of these diseases, together with control measures, will be discussed in detail in Chapter XXI. The fungus causing gray scurf or scab on lemons has not as yet been identified. The fungus apparently acts as a secondary agent; the primary cause is probably the slight bruising of the young tender fruit by the wind. The best remedy for this trouble is the growing of windshields and close planting of the lemon trees. By proper pruning also the branches may be made stiffer and more resistant to the swaying and whipping effect of the wind. The stem-end spot of oranges is a very different thing from stem-end rot, and occurs mostly on Navels and on fruit which has hung late on the trees. It consists of a breaking down, browning, and shrinking of the skin in certain small spots near the stem. Ordinarily this causes little injury, but occasionally during rainy weather a species of Cladosporium grows on the dead tissue of these spots, giving them a black color which detracts very much from the appearance of the fruit. The only remedy at present available for this trouble is to pick the fruit earlv in those orchards where the trouble becomes Blemishes of the Fruit and their Prevention 321 MECHANICAL BLEMISHES Much otherwise good fruit is ruined by carelessly in- juring tlie fruit mechanically. Growers and packing-house men rarely realize how serious are the losses resulting from such causes. Bruises. — Fruit which is bruised by careless handling is almost sure to decay. Careful handling should be the cardinal principle of every picker and packer. When a stack of boxes of fruit is accidentally overturned in the packing-house, the fruit should be set aside for ten days and then sorted over, the decaying fruit being eliminated. Thorn stabs. — ]\Iuch fruit is ruined by thorns. In wet weather such thorn-pricked fruit decays, but in dry weather the broken skin may cauterize and result in a spot. Sometimes a fruit continually swinging against a thorn will develop a thick horny rind at that point, which ruins its appearance. Thornless varieties, careful pruning, and windbreaks are the remedies. Cultivator scars. — Cultivators and other tillage im- plements should be covered by a smooth tin shield which will allow low-hanging fruit to slide over them without injury. ]\Ietal projections on harness are also objection- able. When it is necessary to cultivate close up under the trees a great deal of fruit will be ruined unless pro- tected by some sort of shield attached to the implements. Clipper cuts. — When the use of pointed clippers was in vogue the loss from clipper cuts was very great. Now, however, round pointed clippers are used, and there is no excuse for clipper-cutting the fruit. Stem punctures. — When the stems are not properly 322 Citrus Fruits cut off square and close, they puncture a great deal of fruit in the box,- and as they pass through the packing- house machinery. A close watch kept on the pickers should prevent this. Machine injuries. — Some years ago a certain packing- house foreman complained of excessive decay which could not be explained. Finally one of the employees dis- covered a loose screw in one of the guide bars of the brushing machine hopper. The sharp head projected an eighth of an inch and made a little nick in every orange which rolled by. Passing over the brushes each nick was thoroughly inoculated with decay germs. The guilty screw head was driven home, after which the decay in transit dropped from 35 per cent to 4 per cent. The remedy for this is to keep a close watch for screw heads or splinters on all ma- chinery and for pro- jecting nails in field boxes. Fumigation scars. — Oftentimes fruit is pitted and burned by carelessly overdosing trees with gas during fumigation. Fumiga- tors should be held re- sponsible for such in- jury. Occasionally, however, it happens that a sudden change in the weather or condition of the atmosphere Fig. 123. — Fumigation scars. Blemishes of the Fruit and their Prevention 323 will result in wholesale pitting of fruit even with the same dosage which was harmless a few hours earlier. No remedy has been found for this difficulty, and fumigators are not to blame. Fortunately such occurrences are rare. Shoulder spots. — Where two oranges grow touching each other the point of contact is often shown by a light colored area with a reddish spot in the center. Such spots are not very serious and cannot be remedied unless the fruit be thinned. Thinning citrus fruits has never been practiced in California. Hail scars. — Hail storms are of rare occurrence in the citrus districts. When they do occur they pit the fruit. If the hail is followed by dry weather, most of the pits will dry and little injury will result. In wet weather, however, some fruit will de- cay on the tree with blue or green mold, while in some cases a species of Cladosporium will grow on the pits and turn them black in color. Soil scars. — Where heavy crops of fruit bend the branches down much fruit often rests on the ground. When the wind moves the branches the rubbing of the fruit on the ground causes a gray callous spot which ruins its appearance. Fig. 124. Sear caused by nibbing on the ground. 324 Citrus Fruits JVindf aJ Ls. — OccsisionaWy strong winds will whip a large part of the orange crop from the trees, as was the case in September, 1911. It is rarely safe to send a windfall to the packing-house, as it is very apt to develop decay. Cement dust. — In certain localities the fruit is coated on the upper side with a crust of cement dust which comes from near-by cement mills. This dust collects in the pores of orange skin and sets, being very difficult to remove. It injures the appearance and reduces the grade. PHYSIOLOGICAL BLEMISHES This class of blemishes is not only large and the losses serious but the causes are as a rule not well understood. The total number of troubles of this kind is very large and new ones are continually appearing. Only the most important will be mentioned here. Sunburn. — Both oranges and lemons which hang fully exposed to the sun are often injured. The exposed side becomes dwarfed in growth, resulting in malformation, and the skin of oranges becomes thick and pale colored and adheres tightly to the flesh. In interior valleys where the sun is very hot the skin may die and a hard black spot result. In such situations the trees should be pruned in such a way as to encourage the production of inside fruit, which is always much finer in appearance. Lemons are often noticed in the markets which are lop-sided, the dis- tance from stem to apex being greater on one side than the other. This is caused by shght sunburn and is a sure sign that the lemon grew in an exposed position on the tree. There is a curing house trouble of lemons known as Blemishes of the Fruit and their Prevention 325 red rot, or, more properly, red blotch, which develops as a rusty brown color, gradually drying down into a sunken condition with a dark red or black color. This has been attributed to sunburn, as it is most common in lemons from exposed parts of the trees. Frost. — The losses from frost are of course very large, but many fruits are only slightly frosted, and while they should be packed under a frost label they are good for consumption. Oranges usually exhibit no outward signs of frost unless severely frozen. Occasionally, however, certain oranges, especially those having more or less thick skins and growing low down on the north side of the tree will show a number of characteristic brownish spots on the exposed side even though but slightly frosted. Off-bloom. — Occasionally orange and pomelo trees will blossom out of their regular season. The cause of this is not always apparent, although it is often due to irregu- larities in irrigation. Fruits developing from off -blooms are usually malformed and inferior. Navel off-blooms produce fruits with sunken instead of protruding navels. Pomelo off-blooms produce fruits which are distinctly pear-shaped as compared with the regular crop. Regu- larity and thoroughness of irrigation and cultivation will reduce the amount of off-bloom fruit to a negligible quantity. Mottled-leaf. — This disease is not at present well understood. It results in the production of very small oranges and lemons of a whitish color, often quite unfit for packing. (See Chapter XXI.) E.ranthema. — This trouble appears on the fruit as dark reddish blotches or crusts. In severe cases the fruit is 326 Citrus Fruits dwarfed in growth and cracks open on the trees. (See Chapter XXL) Malformation. — Many kinds of malformations are common. They may be divided into two classes : those due to sporting such as corrugations and color stripes of the rind, bottled-necked fruits, and others, which may be remedied by pruning out all of the sporting branches ; and those due to an excess of food and teratological factors. Many Navel oranges, especially those borne on the top- most branches, exhibit a double or proliferated navel. Often this takes the form of a small secondary orange superimposed upon the navel. These are very common and are always thrown into the cull-heap because the small orange would have to be broken off before packing and this would result in decay. Often twin oranges partly attached are met Avith which are discarded for the same reason. The fruit borne near the large upright central branches often has coarse, grooved skin about the stem. This is caused apparently by the superabundance of food and may be largely prevented by proper pruning. Broum spot. — The brown spot of the Navel orange may be described as occurring irregularly over the surface of the orange. From one to fifty or more spots may develop on a single fruit. The spots vary in size from a mere point to one inch in diameter, averaging about one-fourth inch. This brown spot occurs only on the Navel oranges, and is uniformly worse on fancy, smooth, thin-skinned fruit. The total money loss from this particular spot is very large. For further particulars see Chapter XXI. Cracks and splits. — Cracks differ from splits in being Blemishes of the Fruit and their Prevention 327 transverse rather than longitudinal openings in the rind of the orange. They are of rare occurrence and their cause is unknown. Splits, on the other hand, are very common and cause heavy losses, especially with Navel oranges in interior valleys. Splits are of two kinds : Fig. 125. — Orange splits. Side splits above and navel-end splits below. side splits and navel splits. Side splits are caused by teratological cavities or seams in the skin. Thus weakened the skin is unable to withstand the growth pressure, and a split results. A Navel orange which is split even a fourth of an inch at the navel must not be packed for long distance shipment, for such an opening is almost sure to be inoculated with decay. 328 Citrus Fruits' All such oranges must be graded out but may often be sold to local peddlers for enough to pay for picking and hauling. The most common theory in regard to the cause of splits is that an irregular water supply, causing wide variations in the moisture content of the soil, produces a greater fluctuation in the growth of the interior than in the skin of the orange. Such a theory is quite reasonable, but such a cause should be regarded as contributory only, inasmuch as only a part of the fruit on any given tree will split. If a number of navel-split oranges are cut in longitudinal sec- tions, it will be found, almost without excep- tion, that the thickness of the rind varies, being quite thick and often creased at the stem end, and as thin as paper near the navel. Specimens with uniform thickness of skin very rarely split. Hot, dry spells of weather alternating with damp cloudy weather, together with careless irrigation, cause a high percentage of spHts among this class of oranges. While much may be done toward overcoming this loss by careful irrigation and cultivation, the most important remedy is probably the propagation of trees from carefully selected bud-wood. By this means we may largely eliminate from our future orchards the un- FiG. 126. — Horizontal cracks are very different from splits. Blemishes of the Fruit and their Prerention .329 desirable types which are so prone to split during un- favorable weather. Puffing. — When oranges are left too long on the trees, they will often become puffy. The rind becomes weak, with many cross creases and much unevenness. Finally the whole orange becomes soft and structureless. The walls of the juice vesicles become much thickened and the juice partly disap- pears, leaving the fruit dry, crumbly, and insipid. The remedy for this trouble is to pick the fruit earlier in those localities where putt- ing is serious. Petec a.— This trouble appears in the form of deep sunken pits in the rind of lemons after they have been in the curing house for some time. The tissue at these spots is found to be dried and shrunken prematurely, somewhat after the fashion of the brown spot of the Navel orange. The cause of peteca is not known. Dry center of lemon. — Ps. peculiar trouble which has be- come quite general in recent years. The vesicles collapse 330 Citrus Fruits in groups, turn brown, and dry up. Injury is always greatest near the blossom end and is often accompanied by germination of the seeds while still within the fruit. In advanced cases the interior of the lemon may become filled with a mass of roots from the seeds. While this trouble results in a loss of juice, the housewife who cuts the lemons through the center is not apt to discover their inferiority as there is little surface indication of dry center. In many ways this trouble resembles bitterpit of the apple. At present neither the cause nor a remedy is known. CHAPTER XVIII BY-PRODUCTS Until very recently it has been the custom in Cahfornia to haul the cull fruits from the packing-houses and dump them in waste places. A very few growers returned the culls to the orchards and plowed them into the soil for the sake of their humus value and the small amount of plant-food they contain. But the bulk of the culls have been thrown away, and when we consider the enormous waste resulting from this practice the question arises as to whether a part at least of this large tonnage of fruit may not be profitably converted into valuable by-products. That citrus by-products are in strong demand in the United States is proved by our annual importation of these items from abroad. The imports of the year 1909 are fairly typical of other years and are given on page 332. The values given are the appraised wholesale values at the port of export and would be considerably higher if appraised in this country. At the present time nearly all citrus by-products are produced in Europe, while small amounts come from Paraguay, China, and California. The chief reason why citrus by-products have not been more largely produced in the United States is that the 331 332 Citrus Fruits cost of labor is from three to five times greater tlian in the citrus producing regions of Europe. At })resent, however, there is a widespread interest in this subject in CaHfornia. Several small factories are already in operation, and several more are in process of construction. Importation of Citrus By-products into the United States for the Year ending June 30, 1909 Quantity Value Citric acid — lb Citrate of lime — lb Lemon, lime, and sour orange juice Orange and lemon peel not candied, preserved, or dried Citron or citron peel, candied or dried — lb Citron preserved in brine — lb. . . Orange and lemon peel, preserved, candied, or dried — lb Oil of bergamot — lb Lemon oil — lb Lime oil — lb Oil of neroli or orange flower — lb. Orange oil — lb 243,010 3,917,274 991,341 4,075,835 436,129 89,957 405,695 21,991 23,184 87,591 .S74,209 489,031 81,386 4,833 79,519 100,224 20,692 281,211 358,197 9,973 170,342 151,860 Total .Sl,821,477 In Europe the citrus by-product industry is largely centered on the Island of Sicily and in Calabria. In these districts the two chief products are citric acid and lemon oil. About one-third of the total lemon crop of this region is consumed in the manufacture of citrate of lime, and from the peel of these same lemons comes the By-Products 333 enormous quantity of essential oil, or essence of lemon, which furnishes practically the world's supply. COMMERCIAL BY-PRODUCTS For convenience those by-products at present manu- factured on a commercial scale will be grouped separately from a number of domestic recipes which are included. Several of the products described under domestic recipes may of course be produced on a commercial scale, should the demand warrant. Citric acid. — Citric acid is manufactured from the juice of the lemon chiefly, although lime juice is used to some extent. The peel is first removed and used for the pro- duction of lemon and lime oil which will be described later. The lemons are halved and the pulp scooped out with a sharp spoon. The pulp is then passed through toothed cylinders which shred it, and the juice is extracted from the mass by a high power press. The crude juice con- tains water in abundance, citric acid, malic acid, several kinds of sugar, albuminoids, and mucilage. The crude, juice is filtered, placed in boilers, and heated nearly to the boiling point. Finely powdered chalk, mixed to a cream in water, is slowly added, while the hot liquid is being constantly stirred. The chalk or carbonate of lime unites with the citric acid, forming calcium citrate, which is insoluble and precipitates from the juice as a white powder, which is collected, washed, and dried into cakes. Great care is used to add just enough chalk to take up the citric acid as shown by litmus tests. As citric acid must pay a duty of seven cents a pound on entering the 334 Citrus Fruits United States and citrate of lime is free, most of the Italian product is shipped to this country as citrate of lime, and the final step in the process is completed in this country. This final step consists in treating the citrate with dilute sulphuric acid, which forms svilphate of lime and leaves citric acid in solution. This solution is evaporated in leaden boilers until the pure citric acid crystallizes out, and is washed and dried. Citrate of lime contains about 65 per cent of citric acid. Lemon oil, orange oil, bergamot oil, and lime oil. — The peel of all citrus fruits is thickly dotted with small glands yielding an essential or highly volatile oil. The oils from the different kinds of citrus differ considerably in their characteristics. These oils are in great demand for flavoring extracts and perfumery, and the demand for the different kinds is in the order given. Of these, lemon oil is used in much the largest quantities. Any person may easily demonstrate the presence of this vola- tile oil by squeezing a piece of fresh peel in such a way as to cause the oil to spurt out into the flame of a lighted match. It will burn with a flash, showing its high vola- tihty. The major part of the oils now on the market come from Sicily and Calabria. The contrivances for extracting the oil are very crude, much hand labor being necessary. As before stated, the fact that labor in Italy costs only one-third as much as in California is the chief reason why California has not produced a larger amount of citrus oils. After the pulp has been removed from the halved lemons and pressed for citrate, the peels are soaked in cold water for a few hours to increase the turgidity of the cells. They By-Products 335 are then taken by men who press out the oil entirely by hand. The pressers sit on low stools with a small lipped bowl between their feet. Across the top of the bowl rests a strong notched stick which supports a large sponge. Each half lemon is placed against the sponge and given three or four sharp squeezes, using almost the entire weight of the body. The oil spurting out of the peel is caught by the sponge and drips through it into the bowl below. From time to time the bowl is raised and the oil is blown off by the breath into a graduated glass receptacle, the lip retaining the small amount of water and residue. After the oil is filtered through a paper filter it is ready for market. In (^alabria a crude machine is used in which is a bowl lined with sharp metal points. The fruit is placed whole in this bowl and revolved, the points puncturing the peel, from which the oil drips through an opening in the bottom of the bowl. This device is called an ecuelle, and is used chiefly in the making of bergamot oil, for the reason that bergamot oranges are round in shape and revolve to better advantage in the machine. Some few operators lacerate the rinds of lemons or oranges and distill the oil, but the use of this method results in water white oil of very inferior grade. A large amount of oil of limes is made in the West Indies. The oil is extracted from whole fruit by hand in ecuelle pans, the pulp being later pressed and the juice concentrated by evaporation and sold as lime juice to be used as a drink. Uufermenied orange juice. — " A very palatable and attractive beverage can be made from oranges. The chief difficulty is the mechanical one of rapidly and eco- 336 Citrus Fruits nomically separating the juice from the solid parts of the fruit. The juice can easily be made perfectly and per- manently clear by settling and filtration. Sulfurous acid in very small amounts (4 ounces potassium metabisulfite to 100 gallons of juice, an amount well below the limit allowed by law) is necessary to prevent fermentation and the production of a bitter taste during setthng. The cleared juice keeps perfectly after bottling if pasteurized at 180° F., which does not injure the flavor perceptibly. Good oranges will yield over 1 30 gallons per ton ; frozen oranges a much less amount." ^ Orange oil, for which there is a good demand, may be extracted from the skins of the oranges used in the manu- facture of juice. Orange vinegar. — A good quality of vinegar may be manufactured from the juice of cull oranges w4iich are well matured and have a total sugar content of 10 per cent or more. Cruess ^ has shown that orange juice con- taining 11 per cent will, on fermentation, give about 5.5 per cent of alcohol, and that this on conversion into acetic acid will yield about 5.5 per cent of acid, which is consid- erably over the legal limit of 4 per cent of acetic acid. Inasmuch as many samples of orange juice may be expected to contain 9 per cent or less of total sugars, it is apparent that the resulting vinegar will closely approach or even fall below the legal limit unless considerable care be used in the selection of the raw material as well as in the fermentation process. ^ W. V. Cruess, "Utilization of Waste Oranges," Calif. Exp. Sta., Bull. No. 244, 1914. 2 Ibid., p. 164. Bij-Prodnrts 337 Orange icine. — IMost of the so-called orange wines found on the markets are made from orange juice flavored with orange oil, fortified by the addition of alcohol or brandy, and sweetened by the addition of sugar or sirup. Such liquids, of course, have no right to be called orange wine. An agreeable pure orange wine can be made by the use of proper methods. Such methods consist in " defecating the fresh juice after the addition of moderate amounts of potassium metabisulfite to prevent fermentation for a short time, fermenting the clear juice with pure yeast, and filtering the finished wine to clear it. This cleared wine may be turned into sparkling orange wine by the addition of a small amount of sugar and by subsequent fermentation in bottles." ^ Candied citron. — JNIost of the citron consumed in the United States comes from the Mediterranean region and especially from the Island of Corsica. The chief reason why citron is not more largely produced in California is the difference in the cost of labor. Citron is admitted to the United States from Corsica duty free when it is shipped pickled in brine or ordinary sea water. Practically all imported citron is candied in this country. There is one firm now engaged in the growing and processing of citron near Riverside, California. The fruit as it first begins to assume a bright yellow color is picked and placed in brine for a month or longer, the brine being renewed occasionally. Sometimes tender young leaves of the citron tree are soaked with the fruit to deepen the green color. The fruit is then boiled in fresh water to remove the salt and soften it. It is then 1 Ibid., p. 170. 338 Citrufi Fruits halved, the pulp and seed scooped out, and immersed in cold fresh water to intensify the greenish color. After this it is covered with hot sugar sirup and allow^ed to stand three or four weeks, during which time the strength of the sirup is gradually increased. The fruit is then put into boilers with crystallized sugar sirup and cooked ; then allowed to cool, more sugar is added, and it is cooked again until it will take up no more sugar. It is then dried and packed in wooden boxes, each piece being coated with white sugar crystals and wrapped in tissue paper. Oil of neroli. — This product is made chiefly in the vicin- ity of Grasse in the French Riviera. Neroli is made by distilling the flowers of the bitter or bigarade orange, known in California as sour-stock. Both oil and water pass through the still ; and as they condense the oil col- lects on the surface, is skimmed off, and sells for a very high price (from $20 to $50 a pound). Three hundred pounds of flowers are required to make one pound of neroli. The water which distills over absorbs some perfume from the oil and is sold as eau de fleur d'oranges, bringing about twenty-five cents a gallon. Petit grain oil. — This oil is used in perfumery and is prepared by distilling the young and tender leaves and shoots of both bitter and sweet oranges. It sells for from two to five dollars a pound. A large part of the petit grain oil now comes from Paraguay, where orange trees have run wild and occur in forests over a large area. Tincture of orange flowers. — This is a perfume which is prepared by steeping the fresh flowers in alcohol until all the perfume has been absorbed by the alcohol. Essence of orange flowers. — This perfume is produced Bij-ProHncts 1^39 in large quantities in Europe and imported into this country. Apparently there is no reason, except the high cost of labor, to account for the lack of production in the United States. As orange trees produce many times the number of flowers that are needed for setting a crop, and most of them fall off normally, the preparation of essence need not hinder fruit bearing. The making of the per- fume is a simple matter, and the preparation of a small supply for home use might furnish a pleasing i)astime for young people living among orange groves. In the early morning orange blossoms are collected as soon as the petals begin to fall, by shaking the tree over a sheet spread on the ground. A tree yields from two to ten pounds of flowers. The perfume is generally extracted by enfleurage. Shal- low trays containing layers of fresh blossoms are slipj)ed into the grooved sides of a large air tight box. The box is filled Avith trays, but between each two trays is inserted a sheet of wire gauze or linen holding a thin layer of wax or mixed grease. The odor of the flowers is absorbed by the grease, the flowers being replaced by fresh ones every morning for a month, when the grease, or " pomade " as it is called, is collected and treated with alcohol for a month. The odor leaves the grease and passes to the alcohol, which is then known as essence of orange flowers. Dried and candied peel. — Both orange and lemon peel are in good demand, both candied and dried. When dried, the peel is simply removed from the pulp, cut into thin shreds, and dried in the sun. When candied, the process is very similar to that used for citron, and the orange and lemon peels are not shredded, but left in halves. Lime juice. — Large quantities of limes are grown on the 340 Citrws Fruits- islands of the West Indies. The green Hmes are harvested and shipped to market in barrels, turning yellow on the way. The ripe fruit which falls to the ground is gathered up and converted into several different by-products, such as citric acid, lime oil, and lime juice. In making raw lime juice which is to be used as a beverage, only clean, sound fruit is used. The juice is expressed by passing the fruit be- tween heavy granite rollers. The juice is allowed to stand until the mucilage or albuminous matter is thrown down, after wdiich it is filtered and bottled. If the fruit used is clean and sound, the raw juice should keep without any preservative being added. Lime juice cordial is made by mixing the raw juice with various brandies and other ingredients. Orange paste. — A large amount of orange paste is used by confectioners. It is made by grinding and macerating fresh orange peels, and after the addition of an equal weight of sugar evaporating down into hard cakes which are broken up and packed in wooden buckets. This or- ange paste is one of the few citrus by-products which is already being manufactured in California. Crysiallized baby oranges. — The small green oranges which drop from the trees during June and known as the "June drop " may be gathered and made into a pleasing confection known as crystallized baby oranges. Fruits between one-half and one inch in diameter are best and should be gathered frequently and not allowed to wilt on the ground. The fruits are placed in brine, gradually in- creasing the strength until fermentation is prevented. They may remain in brine indefinitely, provided the brine is changed occasionally. When ready for processing, the By-Produch- 341 fruits are boiled in several chaii<;;es of fr(>sh water until free from salt, and tender, after which a hot weak sugar sirup is poured over them. This solution is replaced by one more dense each day until the fruits will take up no more sugar. They are then dried and dipped in a very thick sugar solution and allowed to cool slowly when the sugar will crystallize out over the surface. The fruit is now ready for packing. Glaced kum.quats. — Chinese and Japanese prepare a quantity of glaced kimiquats, a certain amount of which is shipped into this country. The fruits are jiicked when ripe and several slits made in the sides. Sometimes the seeds are squeezed out through the slits, sometimes not. The fruit is boiled until tender and then carried gradually through a series of sugar solutions of increasing density until they will take up no more. They are then dried and dipped in a very heavy hot sirup and quickly dried. In- stead of crystallizing the sugar will glace over the surface. DOMESTIC RECIPES In addition to the foregoing there are a large number of pleasing preserves, marmalades, and other preparations which may be made to advantage in the home kitchen. Some of these, such as Dundee marmalade, are manu- factured in quantity and shipped to distant markets. While it is deemed inathisable to give a very large num- ber of home receipts, still a few of the more im])()rtant ones may prove of interest and value. Orange or lemon jelly. — Slice fruit thinly, rind and all, place in double boiler with cover, and boil slowly for 20 342 Citrus Fruits minutes without stirring. Press out juice and filter through several thicknesses of muslin. Add a little more than an equal volume of sugar. Boil on slow fire three minutes and pour into jelly glasses while hot. In some cases a small amount of gelatine is added before boiling, but if properly made as above directed this should not be necessary. Orange marmalade. — Large amounts of orange marma- lade are made in Dundee, Scotland, from whence it is shipped to all parts of the world. The oranges used in the manufacture of this marmalade are the bitter oranges grown in the district of Valencia in Spain and shipped to Scotland after being shredded and canned. Most of the marmalade made in California is made from sweet oranges and pomelos. A little of the characteristic flavor of the bitter orange may easily be secured by replacing a few of the sweet oranges with bitter ones. Slice one dozen oranges thin, throwing away ends, and one-half dozen lemons, removing all seeds. Measure the fruit, and add half as much water. Let stand over night. Next morning boil the fruit in the same water until tender. Remove from fire and weigh and to each pound of fruit and licpiid add one pound of sugar. Boil until it jellies, which should require about twenty minutes. Do not have the fruit too ripe ; it should be fresh and firm. Pomelo marmalade. — Slice one pomelo, one orange, and one lemon, rejecting seeds and core. Measure the fruit and add to it twice the quantity of water. Let stand in an earthen dish over night and next day boil slowly until peel is tender. Let stand another night and the second morning measure and add an equal volume of sugar. By-Produds 343 Place in covered double boiler and boil slowly for a half hour or until it jellies. The fruit should not be stirred during boiling. Citrus-rhubarb inarnialade. — Take six pounds of fresh rhubarb, four large oranges, four lemons, and one large cup finely chopped walnuts. Cut the oranges and lemons into thin slices, rejecting ends and seeds. Add to the rhubarb, which has been cut into small pieces. Put four large cups of sugar over this and let stand over night. Next morning add four more cups of sugar and boil down. Just before placing in jars and while still hot stir in the chopped wal- nuts. CHAPTER XIX MARKETING The different methods of selling California citrus fruits may be grouped for convenience under four general heads, which, with the proportion of fruit now (1913-14) sold by each method, are approximately as follows : 13 % ^liscellaneous sales. 5% Sales by independent growers who ship to market. 20 % Independent association sales. 62% Sales through the California Fruit Growers' Ex- change. Under the head of miscellaneous local sales, fruit is dis- posed of in various ways. It may be sold either for a lump sum on the trees to itinerant packers and speculators, or it may be contracted for by hotel syndicates to be delivered as needed. The management of the dining cars and eating houses of a large railroad company, for example, often se- lects certain crops of oranges which are bought for a stated price per pound, to be picked and delivered as needed. Commission men wull sometimes secure a contract for a certain amount of fruit of a certain grade to be delivered in the East or in Australia or Hongkong, and then send an agent around the country buying the fruit wherever it can be secured. Such buyers will usually contract with 344 Marketing 345 some indepeiulent local packing-house tor the packing of the fruit. Under the head of iude})endent grower-shippers are in- cluded certain large growers who have sufficient acreage to warrant a packing-house of their own. In most cases such shippers have old and especially favorable connec- tions in certain markets where their reputation is high and their old customers secure. Independent shippers usually have some special or unique advantage which relieves them, to an extent, from the common vicissitudes of the market. The chief stockholder in a large hotel in Chicago or Boston, for instance, who owns a winter home in an orange grove in California, will naturally ship his fruit to his own hotel for consumption. Independent associations are groups of small growers who have united together in building a cooperative pack- ing-house, yet who for some reason have not afliliated with the Exchange, but sell their fruit through commission men in the various markets. ]\Iany of these associations who think they are doing a little better outside the Exchange would quickly join and support the Exchange should it ever appear in danger of failure through lack of sui)i)ort. They prefer for the present, perhaps, to sail in the calm water close under the lee of the Exchange. THE CALIFORNIA FRUIT GROWERS EXCHANGE This great cooperative organization of growers is the child of necessity. The season of 1892-93 was particu- larly disastrous as far as turning fruit into money was concerned, and the market conditions and arrogance of 346 Citrus Fruits the railroads were intolerable. Accordingly the Southern California Fruit Exchange was organized in Los Angeles on October 2, 1895, in order to provide certain marketing of the fruit by more uniform methods. Ten years later the name of the organization was changed to the present title. The California Fruit Growers' Exchange has its home office in the Consolidated Realty Building in Los Angeles. Its organization is tersely described by G. H. Powell, the General Manager,^ as follows : "The California Fruit Growers' Exchange is an organi- zation which acts as a clearing house in providing the facilities through which 6500 growers distribute and mar- ket their fruit. There are three foundation stones in the exchange system — the local associations of growers, the district exchanges, and the central exchange. The local associations, the district exchanges, and the central or California Fruit Growers' Exchange are organized and managed by the growers on a non-profit cooperative basis, each of them operating at cost, and each distribut- ing the entire net proceeds to the growers after operat- ing expenses are deducted." The local exchange. — "The California Fruit Growers' Exchange comprises 115 local associations, each of which has from 40 to 200 members. The growers usually organ- ize as a corporation without profit, under the laws of Cali- fornia, issuing stock to each member in proportion to his bearing acreage, to the number of boxes he ships, or in equal amounts to each grower. The association assembles the fruit in a packing-house, and there grades, pools, packs, and prepares it for shipment. The associations are man- 1 California Cultivator, March 13, 1913. Marketing 347 aged by a board of directors through a manager and are conducted exclusively for the benefit of the growers. They declare no dividends and accumulate no ])r()fits. The fruit is pooled each month, or for a shorter period, each grower receiving his proportion of the proceeds received for each grade shipped during the pool. ]\Iany of the associations pick the fruit, and some of them j)rune and fumigate the trees for the members. Each association has brands for each grade, and when a carload is ready for shipment it is marketed through the district exchange, of which the association is a member, througli the agents and facilities provided by the California Fruit Growers' Exchange." The district exchange. — "There are seventeen district exchanges. These exchanges are corporations without profit. There may be one or more district exchanges in a community, depending upon the number of local associa- tions and other local conditions. The district exchange acts as a clearing house in marketing the fruit for the asso- ciations through the California Fruit Growers' Exchange and acts as a medium through which most of the business relations between the exchange and the local associations are handled. The district exchange orders cars and sees that they are placed by the railroad at the various associa- tion packing-houses ; keeps record of the cars shipped by each association, with their destinations; informs itself, through the California P^'ruit Growers' Exchange, of all phases of the citrus marketing business ; places the in- formation before the associations ; receives the returns for the fruit through the central exchange, and returns the proceeds to the associations." 348 Citrus Fruits The central c.rrhnugr. - "Tli(> California Fruit Growers' Exchange is a non-j)rofit (•()ri)oration under the laws of California. It is formed hy 17 district exchanges, with a paid-in capital stock of $17(K)-. It is managed by a Board of 17 directors through a general manager, one director representing each, district exchange. The function of the California Fruit Growers' Exchange is to furnish market- ing facilities for the district exchanges at a pro-rata share of the cost. The exchange places bonded agents in the principal markets of the United States and Canada, defines the duties of the agents, and exercises supervision over them. It gathers information through them of conditions in each market, receives telegraphic advices of the sale of each oar, and furnishes the information every day in bulletin form to the local associations. The exchange business is on a cash basis ; it makes prompt accounting of returns to the growers through the district exchanges; takes care of litigation that arises in connection w^ith the marketing of the fruit ; handles all claims ; conducts an extensive advertising campaign to increase the demand for citrus fruit ; develops new markets and performs such other functions as are set forth in the contract between the central exchange and the district exchanges. The central exchange levies an assessment against each district exchange for a pro-rata share of the expense on the basis of the number of boxes shipped. It declares no dividends. It does not buy or sell fruit or any other commodity, and exercises no control either directly or indirectly over sale or purchase. Its function is to provide facilities for the distribution and marketing of the fruit for those shippers who desire such facilities. Under the exchange system Marketing :U9 every shipper reserves the right to regulate and control his own shipments ; to develop his own brands of fruit ; to use his own judgment as to when and in what amount it shall be shipped, and the price he is willing to receive, reserving the right of free competition with all other shippers, including the members of the same organization, uncontrolled by any one. The agent in the market acts directly under the order of the shipper, who determines the prices at which each car shall be sold outside of the auction markets, and all other matters connected with its distribution, the California Fruit Growers' Exchange acting as the medium through which orders pass from the agent to the shipper, but never selling a car or determining the price at which the fruit shall be sold. "The exchange is a democratic organization; the growers exercise control over all matters. JMembership in the exchange is voluntary ; a grower may witliflraw from an association at the end of a year ; an association may withdraw from a district exchange, and a district ex- change may withdraw from the central exchange, — these relations being set forth in the various contracts that hold the members together. There is no attempt on the part of the central exchange to regulate shipments, to eliminate competition, divide the territory or business, or to influ- ence prices. In this connection its functions are to keep the associations informed daily regarding the shipments from the state ; the general movement of exchange cars, the general conditions of the different marketing points ; the prices at which the exchange fruit is sold ; and in furnish- ing such other information as will allow the growers and shippers through their association and district exchanges to 350 Citrus Fruits decide the questions of distribution and marketing for themselves. " One third of the entire shipments are sold at public auction, the remainder through unrestricted private com- petition. There is no uniformity in price in the different brands, because the fruit in each section, on account of the soil and other local conditions, has an individuality, of its own, and every brand sells on its own merits. "The exchange is organized into several divisions; sales, legal, traffic, advertising, insurance, and mutual protection, and a supply department which furnishes the materials used in the packing-houses and on the ranches, at cost to the members. The exchange does not consign fruit. It is shipped on order ; sold f . o. b. ; or sold ' de- livered, subject to usual terms.' The exchange maintains district managers in all of the important cities of the United States and Canada. These employees are exclu- sively salaried agents, engaged only in the sale of fruit, in the development of markets, and in handling the local business problems of the exchange." The money received by the selling agents for fruit is deposited by them in national banks to the credit of the central exchange, which forwards it to the district exchange and is by them distributed to the growers. The exchange has collected more than one hundred and thirty-nine millions of dollars in addition to freight charges for citrus fruits in the last ten years, and the losses from bad debts to date have been less than seven thousand dollars. The exchange returns (f. o. b. California) for fruit shipped in the season 1913-14 were about eighteen million dollars. The exchange carries on two forms of advertising. Marketing 351 Space in daily newspapers in all important cities is bought to the extent of .S2()0,()(M) or more a year. In order to secure the chief benefits of this advertising for the members of the exchange, who pay for it, there has been devised a special quality brand known as " Sunkist " (see Fig. 112), the copyright for which is owned by the exchange. This brand is used by all exchange associations as an addi- tional sticker placed on their best brands only. The tissue paper wrappers used on fruit under this brand bear the "sunkist" emblem and such wrappers are redeemable in part payment for table silverware. This ware is triple plated and of good quality and bears a special orange design. In 1912, 1,750,()()() pieces of silverware were dis- tributed in return for orange and lemon wrappers, and the exchange has become the largest single buyer of this class of silverware in the world. In the Chicago office, forty mailing clerks are required to take care of this business. The expense of maintaining the exchange, including advertising and every other expense, has never been as high as 3 per cent of gross sales, while ordinary commission and brokerage charges of other agencies vary from 5 to 10 per cent for selHng alone. In 1914 the total cost of selling, including advertising and the maintenance of the sub- exchanges, amounted to Of^oV c^^nts a box. It is not a difficult matter to organize an association. The money required for incidental and organization ex- penses will be supplied by the membership fees of five or ten dollars. The money required for buikling the packing- house and beginning work is usually borrowed from the banks on association notes personally indorsed by the directors. When the sale of fruit begins a small amount 352 Citrus Fruits to the box is held back with which to gradually pay off the notes. When real propert>', such as a packing-house and site, is acquired it may be mortgaged for as much as possible in order to relieve the directors of personal liabil- ity on the first notes issued. The membership fee should be kept low in order that new members may join at any time as old members drop out for one reason or another. Most associations desire as large a membership as possible, as it is more economical to pack fruit in large quantities and in a large, well-equipped house. Every association should act squarely and honestly with its customers. Special markets should be developed and fruit of uniformly good grade shipped regularly to those markets regardless of fluctuation in prices. It is usually poor policy to chase high prices by changing quickly from one market to another. It should be the ambition of each as- sociation to develop a high reputation for its brands of fruit on certain markets and then stay by those markets through the season, always striving to give good values and please the okl customers. " The distribution of the oranges and lemons of each grower must be uniform throughout the year on a mer- chandizing basis ; neither the grower nor shipper can af- ford to speculate on the market. The fruit should go forward naturally from each grove during the period when it possesses the best quality for that district. Regular distribution increases consumption ; stabilizes the business of the shipper, the jobber, and the retailer. It furnishes the consumer a supply at the lowest average return be- cause the product is handled by every one at a reasonable distributing profit. The distributing cost of citrus fruit Marketing 353 after it reaches the jobber, like many other food products, represents approximately 45 per cent of the consumer's cost. Erratic, speculative distribution increases the dis- tributing costs ; it results in a lower price to the producer and a higher cost to the consumer." ' Some years ago the citrus growers of Florida sent a committee to California to study the methods of the Cali- fornia Exchange. As a result of this the Florida Citrus Exchange was organized in the fall of 1909, and is now a successful organization. About 22 per cent of the Florida Crop of 1913-14 was handled through the Exchange. Citrus Protective League of California This is a voluntary organization formed in jNIarch, 1906, by representatives of growers, shippers, and shipping or- ganizations in nearly all of the citrus growing localities of the state to handle the public policy questions that affect the industry as a whole. Its purpose is to represent the grower and shipper in handling such questions as : railroad rates and transportation problems ; customs tariffs and other governmental relations ; state and federal legislation that applies directly to the business, and all other questions of a general nature that affect the up- building of the industry, except the marketing of fruit. The League is directed by an Executive Committee of nine and by a secretary and manager, the Executive Com- mittee having been appointed by an Administrative Com- mittee of thirty of the principal growers and' shippers 1 Report of G. H. Powell, General Manager, Calif ornin Fruit Growers' Exchange, 1914. 2a 354 Ciirm Fruits who act as a governing committee, and who were selected from the representative delegates who organized the League in 1906. The League represents about 90 per cent of the growers and shippers of the state, and is supported by funds raised by general assessment based on the num- ber of cars of fruit shipped by each member during the preceding year. In conclusion it may be well to point out that during the last decade the citrus fruit acreage in California has more than doubled. From 1900 to 1914 the size of the crop increased 254 per cent. Li order that consumption may keep pace with this rapid increase in production, it is extremely important that the growers loyally support the organizations which are developing a comprehensive, economical, and efficient system for distributing, selling, and advertising citrus fruits. It is also highly important that a profitable by-product industry be established. A means of disposing of low- grade fruit at home will do more than anything else toward keeping such fruit from glutting the markets and depress- ing the prices of fancy fruit. This is bound to result in an improvement in the grades of fruit shipped to market, with consequent marked increase in consumption. CHAPTER XX PROFIT AND LOSS If the question is asked, " Does citrus culture rccally pay?" we are compelled to answer "Yes and no." It pays handsomely where proper conditions are combined with knowledge, industry, common business sense, and capital. It does not pay in many cases where these things are not combined. Some persons make very large, almost fabulous, profits growing citrus fruits, and these examples are widely quoted by real estate agents and land boomers. Other persons lose money consistently year after year. When we consider the total production of any crop in the United States, such as corn, wheat, or cotton, we find the average yield an acre is surprisingly low. Citrus fruits are no exception to the rule. The Citrus Protective League has collected a great deal of data on the cost of production of citrus fruits, and Victor Xewland, a student at the Uni- versity of California, has worked out the average prices received. Such large collections of figures should not be taken too seriously, yet they possess considerable indica- tive value. It appears that the average l)ox of oranges for the five years preceding 1913 returned a net profit of 15 cents to the grower, while the average box of lemons produced during the same period returned a loss of about 355 356 Citrus Fruits 20 cents. And yet skillful growers have commonly made much higher profits on lemons than on oranges, and a good bearing lemon grove will sell for more money to-day than an orange grove of similar age. This means that there have been a larger proportion of failures with lemons than with oranges. There are, of course, many reasons why some citrus trees fail to pay. Some trees are planted with the object of producing fruit; while others, w^e regret to have to say, have been planted for the purpose of making it easier to sell the land. There is a great deal of land that will grow a beautiful young tree for a few years, but upon which bearing trees will soon fail. A considerable acreage of either very questionable or impossible citrus land has been planted out in large blocks and then divided up and sold to unwary investors, who in most cases are inexperienced persons newly arrived from other parts of the country. Much citrus acreage is sold by mail to absent buyers, a very bad practice. It is strange how many unsophisticated persons there are in Northern cities who will trustingly send their money by mail to some agent with the request that he "Be sure to select a nice orange grove for them." Where there is such an absolute lack of business sense as this, it is not surprising that there are so many failures. Absentee ownership is one of the banes of the citrus business. If a person cannot visit his property at least once a month and look after the various operations in per- son, he should sell out to some one who can. Another trouble is over-capitalization, which is encour- aged by speculation. Many beautiful towns and cities have been built hterally in the orange groves and the in- Profit and Loss 357 crease in value of the land for residence and other pur- poses has increased the cai)ital and taxes to a point where it becomes difficult to make any but the most expertly man- aged citrus orchards pay. INIany orchards are composed largely of degenerate types of trees; many have been ruined by the mottled- leaf disease ; and many are too frequently visited by frost. Let us not dwell too much on the dark side, however, but hasten to give assurance that any one with sufficient capi- tal, a reasonable knowledge of horticultural operations, and ordinarily good business judgment may easily make a good profit raising citrus fruits, ])rovided he or she is careful to see that the following requirements are satisfied : 1. A location in a proved citrus district, reasonably free from frosts and winds and within hauling distance of a packing-house. 2. An easily worked, fertile, well-drained, deep soil, purchased at a reasonable price. 3. An ample supply of good water. 4. Strong, thrifty, clean trees grown from carefully selected buds of standard \'arieties. 5. Proper preparation of ground and planting of trees. 6. Personal care of the trees with conscientious culti- vation, irrigation, fertiUzation, and pruning. 7. The exclusion of scale insects and proi)er treatment for fungus and other diseases. 8. Membership in a local cooperative marketing asso- ciation. These may be called the eight fundamental require- ments for success. Failure in any one of these retiuire- ments may bring about the failure of the grove, although 358 Citrus Fruits failure does not necessarily follow in every case. On the other hand, if each of these requirements is fairly met, success is as sure as almost any horticultural venture can be. In addition to these things it is advisable for the be- ginner to cooperate with the neighbors toward the general good of the district by joining loyally in fumigating and frost fighting campaigns. The College of Agriculture should be freely consulted, and the beginner will usually find it to his advantage to enroll for the free correspond- ence course in citrus fruits conducted by the College. CAPITAL REQUIRED The next question to be considered is, " How much money will be needed to meet the eight requirements for success outlined above ? ' ' This question permits of no defi- nite answer on account of the very wide variations in costs in different localities and under different conditions. In some locaUties good citrus land may still be had at $150 an acre, while in other districts it may be considered cheap at $500 an acre. Water also varies very w^idely in cost. In some locali- ties where there is comparatively little frost, combined with good soil and other natural advantages, the cost of water has soared surprisingly high. After the local supply has all been appropriated, additional water is often brought from great distances. This is usually accomplished by forming a water company which pur- chases sufficient water bearing lands and installs the necessary pumping plants, tunnels, and aqueducts. The necessary amount of water stock in such a company Profit and Loss 359 (which is the water right) sometimes costs as much as $200 an acre and the annual assessments for pumping expense and repairs may be as much as $40 an acre a year. The following estimate gives some general idea of the cost of bringing a young grove into bearing in the San Gabriel ^^alley : Cost of Bringing a Ten Acre Orange Orchard to Bearing 10 acres orange land $1500 Clearing and grading 2000 Water right 1500 Trees, 1000 @ $1 1000 Planting trees at 7^^ each 75 Irrigating system 200 Irrigating and cultivating, 5 years .... 2000 Taxes and incidentals, 5 years 250 Fertilizer, 3 years . . ' 250 Pruning 200 Total expense $8975 Returns from fruit less packing charge, 3 years . . . 1200 Total investment at beginning of 6th year . . . $7775 A well managed orange orchard in full bearing ought to yield 250 packed boxes an acre. Many orchards aver- age much more than this amount. The cultural, packing, and selling costs ought not to exceed $2.00 a box. The average selling price for oranges for the last five years has been about $2.80. At the time the reduction of the tariff on citrus fruits was under discussion in Congress, the Citrus Protective League made an extensive investigation of the cost of producing oranges and lemons. The publications of the League con- tain some very extensive tables showing all items of cost in great detail, from which the following figures are taken : 360 Citrm Fruits Data on 26,000 Acres of Oranges Average cost of materials an acre $83.24 Average cost of labor 52.82 Average cost of crop an acre $136.06 Data on 4,186,983 Boxes of Oranges Cost per Box Picking $.0771 Hauling 0287 Packing 3246 Picking, hauling, and packing $.4304 Cultural cost 8633 Freight 828 Refrigeration 0789 Selling and collecting .07 Total cost laid down in market $2.2706 Data on 1,391,711 Boxes of Lemons Cost per Box Cost of growing $1,000 Cost of picking 253 Cost of hauling 039 Cost of packing 596 Cost of freight 840 Cost of refrigeration 026 Cost of seUing .070 Total cost laid down in market $2,824 In estimating the amount of capital required to conduct a bearing citrus orchard for a year, the following figures, also taken from the League reports, may beiound of value. The cost of superintendence, administration, and depre- ciation are omitted : Profit and Loss 361 Cost of Operating Bearing Grove an Acre a Year of Oranges when Cultivating Pruning Irrigating Fumigating (materials and labor) necessary Spraying (when necessary) Spreading fertilizer Other tree care (propping, caring for sick trees, etc.) Chemical fertilizer Barn^-ard manure (when used) . . . . Water Forage and grain (feed for work stock) . . Taxes Maintenance and repairs Incidentals Frost protection (when used) $18.00 $20.00 S.OO 22.50 7.50 12.00 18.00 20.00 7.50 7.50 2.50 2.50 3.00 5.00 30.00 35.00 30.00 30.00 18.00 20.00 20.00 20.00 12.00 10.00 7.00 7.00 2.50 2.50 30.00 40.00 Tlie above columns of figures are not added for the reason that no orchard requires all of tliese expenditures in any one year. The same orchard would not be fumi- gated and sprayed, and manure would not be applied e\ery year as sufficient supplies are not a\'ailable. These figures are also open to the objection that they represent averages between different districts and hence are not strictly typi- cal of any one district. Inasmuch as they are susceptible to such wide variations, they should be accepted as rough approximations only. See also statement No. 1 on pages 162 and 163. The Citrus Protective League has published the follow- ing figures on average yields including all varieties of or- anges and lemons. 362 Citrus Fruits Year Oranges ave. 26,000 Acres Boxes per Acre Lemons ave. 6137 Acres Boxes per Acre 1906-7 150.1 129.5 167.2 136.7 191.0 157.6 149.1 1907-8 187 1 1908-9 220.9 1909-10 196 1 1910-11 211.2 Average for 5 years 196.2 The average f.o.b. price received for oranges for the last ten years is about $1.50 per box and for lemons $2.00 per box. JUDGING ORCHARDS AND LANDS It is poor policy to examine a piece of prospective land or a bearing orchard without a program. This is espe- cially true when different propositions are to be contrasted with a view to deciding on a purchase. Many inexperi- enced people buy land without digging into it, but this practice cannot be too strongly condemned. In arid countries surface indications are not reliable guides as to what may be expected below the surface. Holes should be dug at least six or seven feet deep in various places and the soil examined for changes in character, hardpan, stone, and so on. It is suggested that the following list of points be used in going over every piece of land. Each point may be weighted after the fashion of a score-card and thus accurate comparisons between different propositions made easier . Profit and Loss 363 Score-card for Citrus Land 1. Freedom from frost. 2. Water; legal right, amount, quality, cost. 3. Kind and quality of soil. Topography. 4. Continuity of tract and freedom from waste land. 5. Freedom from stones and brush. Cost of clearing and grading. 6. Freedom from hardpan. 7. Freedom from alkali. 8. Drainage outlet. 9. Susceptibility to wind. 10. Distance from scale infested orchard. 11. Nearness to town. 12. Nearness to packing-house and railroad siding. 13. Quality of roads. 14. Price per acre. Additional Points for Bearing Groves 15. Uniformity and yield record of trees. 16. Freedom from scale insects. 17. Freedom from mottled-leaf and other diseases. 18. Condition of trees as to pruning and general care. 19. Adaptability of variety to district. CHAPTER XXI DISEASES AND THEIR CONTROL Citrus trees are susceptible to a large number of dis- eases, some of which are due to the attacks of parasites and some to physiological derangements of nutrition. Practically all of the fungus diseases have been investi- gated by scientists and are fairly well understood, while comparatively little progress has been made in the study of physiological diseases. In Florida and some other humid citrus growing regions the fungus troubles are most common, while in California and other places where the climate is more or less arid the fungus troubles are less abundant and derangements of nutrition due to unfavor- able soil conditions, alkali, excessive heat, and perhaps to excessive illumination and transpiration are very fre- quently met with. GUM DISEASES Citrus trees are apt to excrete gum from a number of differ- ent causes, some of which fall in each of the classes mentioned above. Brown Rot Gum-Disease Among citrus growers this trouble is usually known simply as "gum-disease." Until recently it was thought to be due 3G4 Diseases and their Control 305 solely to physiological causes. H. S. Fawcett has now shown that the true cause is none other than that old enemy of the citrus grower, the brown rot fungus Piiihiaciintis citrophthora. Brown rot gumming is most common on lemon trees and is characterized by a copious exudation of gum from the trunk just above the bud union. A certain area of bark surrounding the gum dies, becomes hard and dry with no outer evidence of fun- gus growth, and is often pushed slightly away from the cam- bium by the pressure of the rapidly forming gum. This kind of gum-disease may be largely prevented by avoiding the soil con- ditions most favorable for the growth of this soil-inhabiting fungus. No water should be allowed to stand in contact with the trunk. Heavy or adobe soils should be kept well worked under the trees and prevented from being mounded against the trunks. It will do no harm to draw the surface soil away from the trunks, even exposing the crown roots, provided the irrigation water is prevented from running into the basin thus formed. Fig. 128. — The Fawcett method of treat- ing gum-disease. Note types of scrapers. 366 Citrus Fruits The fungus gains access to the tree either through abrasions of the l:)ark or directly through the lenticels or breathing pores. The bark of the sour orange is very resistant to in- fection and trees budded six or more inches high on sour stock are quite resistant. When a case of Ijrown rot gumming is discovered, the tree trunk shoukl be treated by cutting away every particle of diseased bark and painting the trunk with bordeaux mixture paste, made as follows : one pound of bluestone and two pounds of unslaked lime with water to make a thick whitewash. It is advisable on all heavy, fungus infested soils to apply this paste as a preventive to all healthy trees so situated as to be liable to gum-disease. This treatment shoulil be repeated every second year at least. Botrytis Gumming xA.nother form of gum-disease is caused by the fungus Botrytis vulgaris and is fairly common on old lemon trees growing on low, heavy soils. It occurs on the trunks and is characterized by a much less copious flow of gum but a much more general infection. The outer bark becomes soft and dies gradually from the outside inward, differing radically in this respect from the brown rot gumming. In moist weather the disease is accompanied by cushions of small dark gray fruiting bodies scattered over the surface of the dead bark. The proper treatment is to scrape off the outer dead bark, leaving the inner bark wherever it is alive, and applying the bordeaux paste. Special tools have been developed for scraping and they shoidd be kept in the bucket of paste when not in use. The application of bordeaux paste to healthy tree trunks is suggested as a good preventive for this disease. Diseases and their Control 367 Scah/-bark The sweet orange alone is subject to this form of gumming which occurs in patches quite generally' over the trunk and large limbs to a considerable height. In this case the outer bark l)reaks and comes away in small, dry scales, lea\ing the living bark underneath with a rough and noduled appearance and with a large number of small gum pockets which exude only a small amount of gum. . In severe cases, the infected tree or branch drops its leaves, and after languishing for a year or two, finally dies. In some cases, large vigorous trees may support a few scaly-bark patches for many years without any serious reduction in crop. While this disease has been investigated for a number of years, the cause has not yet been discovered, and no satisfactory treatment is known. Where the disease occurs only on the branches, they should be cut off below the diseased area and burned. Where the disease occurs on the trunk, it is advisable to scrape the bark thoroughly and apply bordeaux paste, inasmuch as in certain instances this has appeared to be of some value. Twig Gumming Young trees and nursery stock are sometimes affected with gumming of the twigs which is apparently caused by copious irrigation when the soil has become too dry. The gum breaks out along the small twigs all over the tree with splitting of the bark, dropping of leaves, and dying back of twigs. Vigorous trees always recover and the trouble may be pre- vented by giving due attention to regular irrigation. Some- times this form of gumming is caused by a period of desic- cating north winfl. Such winds do not affect the mature wood, but often cause the bark to split and drops of gum form on vigorous young shoots. 368 Citrus Fruits Leaf Gamming This is very common, especially on orange trees, in hot localities. Dark reddish colored, slightly raised spots or areas appear on the leaves in places where they have been turned up and the under side exposed to the sun or frost. These spots are formed by the secretion of a gum-like sub- stance in the tissue just under the epidermis and are simply the result of sunburn or frost injury at a time when the leaves are young and tender. The trouble is not serious and need not be feared. Fig. 129. — Reddish gum areas on under side of leaf caused by sunburn. Gumming of Seed Bed Stock (Pijthiacystis citrophthora) It often happens that the brown rottungus, becoming established in the soil used for seed beds, will infect large numbers of sweet orange seedlings, especially where the soil is allowed to become too wet. Many of the seedlings are girdled at the surface of the ground and entirely ruined and have to be discarded when the plants are dug for sale. Sour orange plants are somewhat more resistant, but even they will sometimes show a considerable amount of gumming, as immunity to the brown rot fungus is not fully acquired until after the plants have been transferred to the nursery row. Diseases and their Control 309 In order to prevent this troul)le, the surface soil should he kept as dry as the health of the plants will permit. When the first indication of disease is noticed, the beds should he thoroughly sprayed with bordeaux mixture, applying the liquid in quantities sufficient to drip down and moisten the entire surface of the soil. Exanthema or Die-hack This disease was first described as occurring in Florida in 1875 and has since assumed great economic importance, having appeared in every citrus growing district in that state. The annual losses directly attributable to exanthema are very heavy. In California and Arizona, however, the losses sustained from the eflfects of this disease have been comparatively light. It has been reported from several localities in southern California, but in very few cases has the outbreak been widespread or sufficiently severe to attract very much atten- tion. There is a widespread misunderstanding in regard to the term "die-back." There is of course a dying back of the branches due to any one of a very large number of causes, such for example as mottled-leaf, cottony-mold fungus, frost, and the like. Seemg dead twigs in their trees, many persons are apt to jump to the conclusion that the trouble is die-back, which presents itself to their minds as a vague though no less terrible malady, the symptoms of which they do not clearly understand. The term "exanthema" is a Greek word meaning an eruption or pustule which was given to this particular disease by Swingle and Webber in 1896 and is much to be preferred to "die-back." There is only one exanthema but there may be many kinds of die-back. Exanthema has more symptoms than almost any other 2b 370 Citru.s Fruitfi plant disease, and there is little excuse in failing on a diag- nosis. The first indication of exanthema appears as an ab- normally dark green color of the leaves near the center of the tree. This is followed by a dying back of the young growth with the formation of small swellings or gum pockets at the nodes. These often crack open and tears of gum are exuded from the very young twigs, while the cracks on larger twigs appear filled with a red or brown gummy substance. Often af- fected twigs will attempt a new growth but succeed only in form- ing clusters of sickly, pale colored buds in the axils of the leaves. Water sprouts often arise from healthy wood below the diseased tissue, which in turn may or may not become affected. The fruit on badly affected branches either falls or remains small and pale yellow in color. Usually the fruit which reaches some size exhibits a very char- acteristic dark brownish red stain which appears as irregular patches of gummy material laid over the surface. These red areas are usually slightly elevated, and badly affected fruit often splits open longitudinally while hanging on the tree. Affected fruit is usually abnormally thick skinned, contains numerous Fig. 130. — Exanthema pustules on Valencia orange twigs. Diseases and their Control o71 gum pockets at the center, and in tlie case of oranges has an insipid sweet taste. In many cases exanthema is accom- panied by mottled-leaf, although this is prol)al)ly merely a coincidence, as there is no known connection between the two diseases. Exanthema is most common on the orange al- though it has been found by the writer on both lemon and pomelo. From all its appearances exanthema would naturally be supposed to be a fungus disease, but this appears not to be the case. A great deal of scientific investigation has been ex- pended, but as yet no fungus or other parasite has been found connected with the trouble. Experiments have shown moreover that the disease can be produced in healthy plants without the aid of any parasite whatever. For these reasons it is considered to be a physiological derangement of the vital functions caused by irregular or improper food and moisture supply ; in other words, a form of plant indigestion. Citrus plants appear to be especially susceptible to various forms of malnutrition. In Florida the cause of this condition has been fairly well established. It has been found to be due to an excess of ammonia in the soil resulting from applications of stable manure or other form of organic nitrogen. Florida growers are almost certain to huxe exanthema if they apply large amounts of dried blood or cottonseed meal, or i)lant the trees on land previously occupied by cattle pens or chicken yards. By being scrupulously careful to avoid these things Florida growers have been able to reduce the amount of exanthema to a minimum. In California, however, the conditions are very dift'erent. Here growers apply organic manures in very large amounts with apparent impunity, as far as exanthema is concerned. Why this marked difference should exist is certainly a mys- 372 Citrus Fruits tery, but it exists nevertheless. The chief causes of exan- thema in CaUfornia are improper soil drainage and faulty soil structure ; or as Lipman has recently suggested, the direct cause may be an abnormally slow nitrification in the soil accompanied by abnormally rapid ammonification, thus forc- ing the plants to take up ammonia compounds. Exanthema may be cured entirely by the removal of the conditions causing the trouble. Where ground water is the cause, the land may be drained, but where an open porous subsoil allows the water to pass down, but on account of its open nature does not permit the return of the water by capil- larity, the remedy is very difficult or impossible. Such lands should not be planted to citrus fruits. Mal-di-gomma or Foot-rot In European citrus districts as well as in Florida foot-rot has caused heavy losses. In California, however, it is com- paratively rare. It is thought to be caused by a fungus of some kind which produces rotting of the roots quite distinct from that described above. The decay starts in the bark of the main roots, which becomes soft and slimy, and gradually spreads from the surface of the ground downward. This is accompanied by a yellowing and drop- ping of the leaves in that part of the top directly over the diseased roots. When disturbed, the rotten roots have a peculiar and offensive odor. Lemon roots are quite susceptible, sweet orange somewhat less so, while sour orange is quite resistant. Apparently the only conditions under which the disease can exist are extremely poor drainage and very wet, heavy soil about the roots. Badly diseased trees are difficult to revive but may be replaced provided the soil conditions are improved. Diseases and their Control 373 The use of sour orange stocks together witli good drainage and aeration of the soil are the l)est methods of prevention. Toadstool Root Rot Most mushrooms grow only on dead material hut there are some which are actually parasitic on living plants. The mushroom known as Armillaria mellea has caused heavy losses of fruit trees both in Europe and America. The fungus is native to the roots of oak and some other trees and occurs most commonly on lands previously occupied by oak trees. After the oak trees are cut down, the fungus lives for some years on the dead roots in the soil and should citrus trees be planted on the land at once, their roots are very likely to become infected. The fungus usually kills the tree in from two to four years, although in some instances diseased trees may remain alive, though unprofitable, for an indefinite period. In affected trees, usually only a part of the top dies at first, the dead branches gradually increasing in number. If the roots are examined, certain ones will be found decayed and soft. Just under the bark may be seen fan-shaped pieces of felty white fungus with the not unpleasant odor of fresh mushrooms. Soon after a root is attacked there may be seen along the side, and closely appressed to the bark, the rhizomorphs or long black strands of the fungus which re- semble hay wire, although very crooked. During prolonged periods of rainy weather, the fungus sends up from the diseased roots large clusters of a dozen or more toadstools which are brownish tan in color, six to ten inches high, and each one, where not crowded, three or four inches broad on top. Armillaria lives only on the roots of the trees and can- not remain for any length of time in soil which contains no tree roots. There is no danger (as some think) of in- 374 Citriis Fruits creasing the spread of the fungus from tree to tree by appli- cation of barnyard manure. From the nature of this trou!)le it is apparent that no such remedy as spraying the fohage can have the least effect on the disease. There is at present no satisfactory remedy. It is not known whether sweet, sour, or pomelo root stocks are equally susceptible. It is urgently recommended that four or five years at least be allowed to elapse between the digging out of all oak roots and the planting of citrus trees, in order that the fungus may die out. During this time, the land may be planted to vegetables or alfalfa if water is available. MotfJed-lcaf For the past ten years a very peculiar and baffling disease of citrus trees has been gradually extending through southern California. It is known as mottled-leaf, and up to the present time has been considered to be a derangement of nutrition due to physiological causes. This disease is probably the most serious problem now before the California citrus growers. The injury to some of the finest orchards in the state has amounted to millions of dollars in the aggregate. Mottled-leaf is a kind of chlorosis of which there are several common on citrus trees. Mottled-leaf, however, is the only form which is widespread or very serious. The trouble first appears as light colored areas situated between the veins of the leaves. The contrast between the color of the veins and interspaces is very striking. Mottled leaves are found only towards the ends of the shoots and represent leaves in which the green color has never completely developed, rather than those in which the chlorophyll has once existed and then disappeared. Leaves which are once green never become typically mottled, although they may become lighter Disrascs and their Control 375 Fig. 131. — Mottled-leaf di-scase on Eureka lemon. 376 Ciiru.s Frnih- in color or even brigyit yellow, iis in other forms of chlorosis. As the mottling increases there is a decided shortage in yield of fruit and in ])ad cases the fruit present is very small, and turns pale yellow or white when about an inch in diameter. There is considerable dying back of the branches and many sickly shoots put out along the trunk and large limbs. In a good many symptoms this disease is similar to peach yellows. Mottled-leaf affects all kinds of citrus trees, regardless of the kind of stock they are budded upon. It affects other trees also, including elm, maple, camphor, eucalyptus, and particularly Japanese privet. The disease occurs in many parts of the world, but apparently it has been seriously de- structive only in California. It is quite general in the Riverside-Redlands district, at Corona, Rialto, Bloomington, Pomona, and Covina. In San Diego, Ventura, and Santa Barbara counties it is much less severe. It occurs in parts of Tulare County. In the Sacramento Valley it is as yet ex- ceedingly rare in spite of the fact that many carloads of slightly mottled nursery trees from southern California have been set out. A great deal of scientific investigation and study has been put upon this disease and a great many theories have been advanced as to the cause. Up to the present time the true cause has not been definitely proven nor has a satisfactory remedy been clearly demonstrated. Some years ago the writer, working on the hypothesis that mottled-leaf, like peach yellows, might be transmitted by buds used in propagation, performed the following experi- ment : buds from badly mottled twigs of both oranges and lemons were inserted in healthy sour orange stocks. On ac- count of the weakness of the buds only a few grew, but these finally grew up into as healthy trees as any in the nursery. Diseases and their Control 37' This showed that mot- tled-leaf is not trans- mitted by budding. In 1910 R. R. Snow- den ^ advanced the theory that mottled- leaf was due to an ex- cess of magnesia or an improper ratio be- tween magnesia and lime in the soil. Snowden showed that the soils of some healthy groves aver- aged about 2.5 parts of lime to 1 of mag- nesia, while the soils from sickly groves averaged 1.18 of lime to 1 of magnesia. This theory was much dis- cussed at the time, but subsequent study brought to light so many exceptions to the supposed rule that the theory was greatly weakened. Heavy ap- plications of lime moreover have by no means proved a cure for the disease. Fig. 132. — Advanced stage of luottlccl- leaf disease showing formation of mul- tiple buds. » California Cullivator, Aug. 11, 1910. 378 Citrus Fruits Some prominent citrus growers have held that starvation or a lack of humus in the soil is the cause of the trouble. In answer to this it may be said that some of the worst affected groves in the state are situated on apparently ideal soil and are among those best fertilized and otherwise well cared for. Mottled-leaf is much more prevalent on sandy and gravelly soils than on heavy adobe soils. In orchards where a certain area or streak of mottled-leaf runs through the orchard this usually corresponds to an area where the subsoil differs much from the top soil, usually being more coarse and open. This has led Smith * to conclude that " the most prevalent and typical form of mottled-leaf is due to an irregular supply of moisture and plant food." In 1912 J. R. Hodges, an horticultural inspector at Covina, California, noticed nematode worms in the soil near the roots of trees suffering from mottled-leaf. He advanced the theory ^ that the disease was caused by these nematodes. The matter was further investigated at the University of California Pathological Laboratory at Whittier where it was discovered that the nematodes were actually parasitic on the roots. E. E. Thomas of the laboratory staff published a preliminary report ^ on the distribution of nema- todes in the state and the possible relation between the worms and the disease. The nematode theory was by far the most plausible of any offered up to that time and at once attracted the attention of many scientists to the problem, which was now attacked from an entirely new angle. The name with a description of this nematode worm is given in Chapter XXIV. Several years will be required for the definite working out 1 R. E. Smith, Cat. Sta. Bull. No. 218, p. 1139. 2 Cat. State Com. Hort. Mo. Bull, Vol. II, No. 6, p. 555. 3 University of Col. Agr. Exp. Sta. Cir., No. 85, February, 1913. Diseases and their Control 379 of the relation between nematodes and mottled-leaf. ISIean- wliile a great deal of sur\'ey work is being done. The theory is still held in abeyanee on account of the fact that the worms are not always found on the roots of mottled trees and they are occasionally found in small numbers on the roots of apparently healthy trees. Experiments are now being carried on with potted trees in sterilized soil which has been inocu- lated with the nematodes. In May, 1914, Kellerman and Wright ^ published the theory that mottled-leaf was commonly caused by nitrogen star\a- tion following the plowing under of mature straw rather than a green cover-crop. It was explained that the mature straw contained large amounts of cellulose and that the molds and bacteria which decomposed the cellulose in the soil used up the available nitrate nitrogen present in the soil. They suggested further that in maintaining the humus of citrus soils, green, succulent materials be used rather than mature or dry straws. While this theory appears to be borne out by greenhouse experiments it is considered inadequate to ac- count for any large proportion of the mottled-leaf disease in California. Perhaps the most plausible theory yet offered is that recently published by Chas. B. Lipman.^ It is explained that a poor nitrifying power on the part of the soil, with the ammonifying power remaining normal, may result in the change of practically all the nitrates in the soil to ammonia compounds. It is further shown that while some plants, such as rice for example, prefer their nitrogen in the form of ammonia compounds, that such compounds are actually 1 Joiir. Agr. Research, Vol. II, No. 2, pp. 101-113. 2 "The Poor Nitrifying Power of Soils a Possible Cause of Die-Back in Lemons." Science, n. s., Vol. XXXIX, No. 1011, May 15, 1914. 380 Citru.'i Fruits poisonous to citrus trees, which show a decided preference for nitrates. With the condition in the soil favoring slow nitrification and rapid ammonification the trees are forced to take ammonia compounds or go without nitrogen entirely, as in many California soils the ammonia resulting from the decomposition of organic matter is actually set free in the air and lost entirely. Experiments are now being performed in the hope of finding a practicable method of treating orchard soils which may accelerate nitrification and at the same time retard ammonification. Spot on old lemon loaf due to withcr-tip. Withcr-tlp (CoUdotrichum gloeosporioidcs) This disease is said to be quite common in Florida and especially on limes in Cuba, causing a spotting of the old fruit and leaves, killing back the twigs, and causing the young newly set fruit to drop ofp.^ In California, however, it ap- ' A recent investigation at the University of California has shown that in Cuba and Florida, two distinct diseases have been confused. The killing and deforming of young foliage and fruits of the Hme are due to a fungus which somewhat resembles Colleto- trichum gloeosporioides but is entirely distinct from it. This Disca,sfs and their Control ;i81 pears to be of little practical importance, for although the fungus has long been present in abundance throughout the citrus growing areas, it very rarely attacks healthy trees as an active parasite. On senile leaves or young leaves weakened by fires, frost, fumigation, or otherwise, it causes dead spots, on the surface of which may be seen the minute black fruiting bodies of the fungus. The fungus occurs also on twigs weakened from any of the above mentioned causes. Trees suffering from gum-disease, foot-rot, gopher injury, alkali, or from other troubles, often show an abundant growth of wither-tip. Spraying with bordeaux mixture will reduce the amount of the fungus, but perhaps a more logical procedure would be to remove the causes of weakness and promote a healthy and disease-resistant growth. In certain rare cases, especially in very wet, cold weather and near the coast, it is possible of course that this fungus may occasion- ally act as a true parasite, in which case spraying with bordeaux mixture is a simple remedy. Certain very small red or salmon colored spots which sometimes occur on lemons in Ventura County have ))een found to be due to this fungus. It may be added that chiefly on account of its common name, "wither-tip," orchardists are very apt to refer to a large number of their tree troubles as wither-tip which are in no way attributable to CoUctotrichum glcposporioides. new fungus has been called Gloeosporium limeiticolum. It causes a very injurious disease of limes and may attack lemons under artificial conditions but has not been known to do so under natural field conditions. Oranges and pomelos are not attacked. Extremely warm and humid atmospheric conditions are neces- sary for the development of the fungus, and it is not known to occur in California. See Clausen, K. E., "A New F^'ungus Concerned in Wither-Tip of Varieties of Citrus Medica," Phyto- pathology II, 6, 217, December, 1912. 382 Citrm Fruits When lemons which have l)een grown in the warmer sec- tions are stored for a long time they finally break down with a soft rot at the center known in the packing-houses as " old age decay" or "core rot." The general exterior appearance of the lemons may be normal, but when pressed between the fingers they collapse. This decay is not yet clearly under- stood but is prol)al)ly due primarily to the wither-tip fungus, which usually kills the buttons after they have been weakened by age. Later, as the fruit ages and becomes less resistant to encroaching organisms, a species of Altcrnaria penetrates the fruit by way of the dead button, following and turning brown the central core of pith and also the fibrovascular bundles as they radiate through the spongy tissue of the rind. The juice vesicles seem to be the last to be affected. After the vascular system is broken down the lemons lose their elasticity and appear dead to the touch. Fruit in such a condition should not be shipped, as it has very poor carrying qualities and decays very quickly when exposed for sale in warm weather. The chief remedy for this trouble is to avoid allowing the fruit to ripen on the trees, and to store in houses where the temperature may be accurately controlled. When the buttons succumb to wither- tip the fruit should be closely watched and hurried to market at the first indication that the fungus is entering the fruit. Twig blight (Sclerotinia Ubertiniana) All kinds of citrus trees sometimes exhibit a sudden withering and dying of small twigs and occasional branches up to one inch in diameter. The green leaves suddenly wither and remain attached to the twig, which dies from the point of infection outward, and with its dead leaves shows very prominently in the green foliage of the tree as though it had been broken and remained hanging. At the point Diseases and their Control 383 of infection a few drops of gum usually form. During rainy weather the sclerotia (small black bodies a little larger than a grain of wheat) will often be formed on the outside of the bark near the point of infection. Sclerotia rarely form in hot, dry weather. Apparently, infection can only occur by spores finding lodgment in abrasions of the bark. While the spores of this fungus are very plentiful in southern California, often causing serious losses in the packing-houses, yet for reasons not at present understood, blighting of the twigs is so rare as to cause but little damage. While the casual observer may notice a blighted twig here and there in almost any orchard either of oranges or lemons, it has never been reported as doing sufficient damage to the trees to warrant remedial measures. This trouble is very often mistaken for wither-tip. As a matter of course all blighted branches should be removed when the trees are pruned. This fungus has also been found on the l)ark and roots of old trees. The bark is decayed and, when dried out, comes away in fibrous shreds very characteristic of this fungus. Remedial measures for this form of the disease have not been worked out. Meanwhile the treatment advised is to cut away all diseased tissue and paint the wound thoroughly with bordeaux paste. Cottony mold (Sclrrotinia lihcrtinicma) The same fungus described above develops not only on citrus twigs l)ut upon the vetch used as a cover-crop and on orchard soils. The sclerotia which form on the twigs and on the vetch finally dry and fall to the ground. The following rainy season, after being thoroughly moistened they give rise to small funnel-shaped toadstool-like bodies which produce the spores of the fungus in great quantities. These spores apparently require an abrasion in order to germinate and 884 Citni.i Fruits grow in the fruit. Once the fungus has begun growth in a lemon its progress is rapid. A hirge amount of white Fig. 134. — A " nest " of cottony fungu.s cotton-Uke myeehum is produced in which the characteristic black sclerotia are formed. An important point to l)ear in Diseases and their Control 385 mind is the fact tliat wliile the spores of the fungus require an abrasion for inocuhition, the white mycelium is abun- dantly able to grow into and infect a perfectly sound lemon at any point. The decay is often very serious in stored lemons, the fungus spreading rapidly in all directions from the lemon originally infected. Unless discovered and re- moved in time cottony mold often destroys an entire half- box or even a whole stack of stored lemons. For this reason packing-house men are always on the watch for "nests" of the cottony fungus, carefully removing the source of infection as soon as discovered, and disinfect- ing the contaminated boxes vnth very strong bluestone solution. The disinfecting solution used in the wash-water against brown rot does not kill the thicker walled spores of this fungus; in fact, bluestone solution of sufficient strength to kill the spores would produce serious spotting of the lemons. Preventive measures must therefore be taken in the orchard when the lemons are picked. It is suggested that the lug- boxes be placed on bare grovmd or at least not left standing for days in the vetch where the spores of the fungus are pro- duced. Empty boxes so placed may easily become dusted with spores, and inasmuch as it is the custom in many houses to submerge the full lug-boxes in the wash-water as the lemons are gently emptied, the spores are reaflily transferred to the water. The cut surface of the stem of the lemon where it was severed from the tree affords ample opportunity for spore infection in the washing-tank. Cottony mold is most severe on lemons and occurs sporadi- cally, being worse in certain sections and in certain years. It may be wise to temporarily discontinue the use of vetch as a cover-crop in orchards where cottony mold has become well established. 2c 386 Citrus Fruits Broum rot fruit decay {Pythiacystis citrophthorn) It has been shown that tliis fungus causes gum-disease of the tree. It also causes a serious decay of the fruit. The fungus hves normally in the soil even at considerable depths. It comes to the surface during wet weather in winter and produces spores on the surface of the ground, especially in damp, shady places, such as under citrus trees. The spores are motile and can swim around in a thin film of water. The drip from the tree splashes these spores upon fruit hang- ing within two or three feet of the ground. The spores enter the stomata or breathing pores, germinate, and grow within the fruit, producing a soft, watery decay which has a peculiar brown color and a characteristic odor. All citrus fruits are affected, but lemons are especially susceptible. During wet winters, the losses from this cause are often very great. The decay spreads rapidly in the packing-house as the mycelium is able to infect perfectly sound fruit by con- tact. If not discovered and removed, the decay starting from one lemon may run through an entire box or a stack of boxes in storage, and, in a short time, reduce the whole to a watery mass. Fortunately a simple and very effective remedy is now in use in all packing-houses. The spores of the fungus being very thin walled are extremely susceptible to copper sulfate, and in order to free any packing-house of this pest it is only necessary to add bluestone to the wash-water. The common practice is to add 1| pounds of bluestone to each 1000 gallons of water in the morning and then fortify this with an addi- tional pound at noon after considerable fresh water has entered the tank. As bluestone attacks metal, wooden or cement tanks should be used. Some prefer metal tanks coated with asphaltum. Should the wash-water contain Diseases and their Control 387 alkali the hluestone may be neutralized, and in such cases a chemist should be employed to study the water and advise as to the proper procedure to keep the solution of bluestone as near as possible at a strength of 5^0^ of one per cent. In order to reduce to a minimum the loss of lemons on the trees it is advisable to keep the branches pruned up some- what from the ground, and summer cultivation should extend well under the trees. It has been found well worth while also to spray the ground under the trees each fall before the rains begin with bordeaux mixture, as this largely pre- vents the fungus from fruiting at the surface of the ground. Blue mold (Pcnicillium itaJicum) arid green mold (P. digitatum) Most of the decay of citrus fruit is due to blue and green molds. Being only very slightly parasitic on uninjured fruit, the decay is practically confined, under ordinary conditions, to fruit which has been injured in handling. The spores of these fungi are very common in the air everywhere and are almost sure to get into any slight abrasion of the skin of fruit. They produce a soft rot while the fungi fruit abundantly over the surface, the spores appearing as a blue or a greenish powder according to which species is present. Frequently the two kinds occur together, although the green is the most universal. For all practical purposes these two species of penicillium may be treated as one. About the only difference is the color of the spores and the fact that in pure culture the blue mold shows a wider l)and of white exposed mycelium between the fruiting area and the sound skin. The universal preventive for these decays is careful handling of the fruit in field and packing-house, which, if conscientiously enforced, will reduce the losses to a minimum. 388 Citrus Fruits Gray mold (Botrytis vulgaris) Occasionally lemons while in storage will develop what is known as gray mold. It appears as a dark brown discolora- tion and softening which is followed by the mycelium which appears at the surface and produces gray or mouse- colored spores. The fungus is apparently dependent on abrasions for access to the fruit and would no doubt be much more abundant were it not for the fact that the blue and green molds usually monopolize such opportunities for development. Black rot of Navel orange (Altcrnaria citri) Navel oranges only are subject to black rot which may be recognized by the premature ripening, abnormally large size, and very deep red color. The affected fruits are very conspicuous on the trees liefore the main crop has col- ored up. The spores of the fungus gain entrance at the navel end through slight imperfections of the peel or per- haps through the stigma of the blos- som, and produce a black, decayed area under the skin. This decay does not immediately spread through the entire Fig. 135. — Black rot of Navel. Diseases and their Control 389 fruit, but remains for weeks as a small black mass of fungus. Decayed tissue may occasionally extend to the surface, but more often this is not the case and the fruit finds its way into the hands of the consumer. There is no known remedy for this trouble which occa- sionally affects as much as one per cent of the crop in certain localities. It is suggested, however, that all affected fruits should be gathered up and burned in order to reduce the num- ber of spores in the orchards. Brown spot of Navel orange The brown spot of the Navel orange may be described as occurring irregularly over the surface of the orange. From one to fifty or more spots may develop on a single fruit. The spots vary in size from a mere point to one inch in diameter, averaging about one-fourth inch. In outline they seem to follow no rule and may be quite irregular, although the cir- cular spot is most common. The color of the spot varies in different localities from a pale brown, which attracts little notice, to almost black, in which case the good appearance of the fruit is ruined. The eating qualities of spotted oranges are not injured in the least. The color of the spot seems to be lighter near the coast and darker in the interior valleys. Losses from brown spot have been heaviest from the upper San Gabriel and Santa Ana valleys, because in these regions the spotting is more common and the color changes to a darker brown. On the other hand, the fruit from many of the pack- ing-houses near the coast shows brown spots of such a pale tint as to attract no notice on the market. The spots are darker on early picked fruit, and it seems to be true that if the fruit is left on the trees until very late it will not spot at all. The spots are slightly sunken on account of the fact that the surface cells have collapsed. The dead and col- 390 Citrus Fruits lapsed tissue extends from the surface to about one-fourth the thickness of the rind. No spots are visible while the fruit is on the trees and as a rule the spots are not noticeable till from 15 to 25 days after picking. On this account it is not possible to grade against this spot in the packing-houses, unless storage houses of sufficient capacity are built to hold the pickings of three or four weeks. The brown spot has l)een observed so far chiefly on the Wash- ington Navel orange, and dealers have com- plained of it only on this variety. In 1914 the writer received specimens of Valencia oranges from Highland which had been picked about the first of June which showed almost typical brown spot. The color was lighter and less damaging than usually occurs on the Navel. Spotting is uniformly worse on fancy, smooth, thin-skinned fruit. The fruit which grades highest as it comes from the orchartl always spots much more than the rough fruit, which often remains exempt. Examination of the spots with a hand lens fails to show any abrasion or opening in the epidermis. Orange packers have been complaining of the brown spot for only four or five years, but it is probable that it has existed, though varying in severity, as long as the Navel orange has been cultivated in California. Fig. 136. — Brown spot of Navel orange. Diseases and their Control 391 Up to the present time neither the primary cause nor a remedy has been discovered. After an extended investiga- tion the writer was led to conchide ^ " That the direct cause of brown spot is the oxidation of the protophism by enzymes which occur in the protoplasm itself but which are prevented from acting as long as the orange is joined to the tree and receiving water and certain nutritive substances from the tree. Thus the resistance of the protoplasm to enzyme en- croachments gradually grows less from the time the orange is picked." This conclusion merely takes the real question one step farther back, for the practical citrus men will, of course, wish to know the primary causes which bring about such premature death. This question cannot be answered at the present time. Damping-off (Rhizodonia sp. and Fusarium sp.) Citrus seed-beds are often seriously injured by damp-oflF fungi. The very young plants begin to die in spots which, rapidly extending, involve large areas if not checked. Two forms of the disease are recognizable, one caused by the Rhizoctonia which kills the stem just above the ground, while the other shows itself in dead spots on the stem at any point. These troubles should be prevented by strict attention to proper methods of planting and watering. No manure or freshly decaying organic matter should be applied to the seed-bed, commercial fertilizers being used exclusively. The seed should be covered with a layer of clean, fresh sand which will prevent the surface from becoming too wet. For the inexperienced grower, particularly, it is better to make wide furrows, two inches deep, about a foot apart, planting the seed broadcast on the ridges between. The water may then ' "The Brown Spot of the Navel Orange," Proc. Soc. for Hort. Set., 1900. 392 Citru.s Fruits be run in these furrows and allowed to soak into the ground laterally, thus keeping the surface of the sand dry. ^Yhere the seed is sovm. broadcast over the whole surface of the bed and the water applied by sprinkling, watering should always be done on sunny mornings and no oftener than is absolutely necessary. In most cases a good watering once a week is sufficient to keep the soil under the sand sufficiently moist. Should the seedlings begin to damp off in spite of all precau- tions, it is advisable to allow the bed to go as dry as is reason- ably safe, and then spray the surface of the bed with a rather weak bordeaux mixture, being careful to wet the entire surface of the soil. Citrus Canker Very recently a new disease has appeared in the Gulf States which is described as the most serious which affects the pomelo. Sweet oranges are apparently immune. It exists in Florida and Alabama, the first specimens being collected in 1912. So far it has not been reported from California. H. E. Stevens describes the trouble as follows:^ "The disease appears as small, circular spots, from less than one- sixteenth to one-quarter of an inch across. They may occur singly, or several together may form an irregular area. They are raised above the surrounding tissue, are light brown, and composed of a spongy mass of dead cells covered by a thin (white to grayish) membrane that finally ruptures and turns outward, forming a ragged margin around the spot. The general appearance of the spots is much the same whether they are found on the leaves, fruit, or twigs. The older spots often become overgrown with saprophytic fungi, and may be pink or black on account of secondary infection by species of Fusarium or Cladosporium. 1 "Citrus Canker." H. E. Stevens, Florida Exp. Stn. Bull. No. 122, 1914. Diseases and their Control 393 "The infections on the leaves appear first as small watery bulging (lots, which are usually of a darker green than the surrounding tissue. They may appear on either surface of the leaf, but do not penetrate through the leaf tissue at this stage. The spots gradually increase in size, change to a light brown color, and become visible on both sides of the leaf. The spot may project from the surface on one or both sides of the leaf. Each spot is surrounded by a narrow yel- lowish band or zone. Later the surface of the spot becomes white to grayish, and finally ruptures, exposing a light-brown spongy central mass. "The spots on the fruit are similar to those on the leaves. They project from the surface and retain a circular outline. They do not penetrate far into the rind, and may be scattered singly over the surface, or several may occur together, forming irregular masses. "The spots on the older twigs are more prominent and usually larger and more irregular in shape. They show the same spongy tissue and the same color as those on the leaves. On growth more than a year old, the spots assume a cankerous appearance and the membrane covering the surface disap- pears. The spots do not penetrate to the wood, but are con- fined to the outer tissues of the bark. "The organism causing the disease has not been deter- mined, but it is probably a fungus. Several different fungi have been found associated with the spots, among which a species of Phyllostida^ occurs most frequently. This fungus is suspected of being the cause of the trouble, and experi- ments are now in progress to determine this. "The disease is infectious, as is shown by the results of some experiments in which it was transferred from diseased material to healthy leaves and shoots of grapefruit." ' Later found to be a species of Phoma. See Wolf and Massey, Circular 27, Alabama Experiment Station. 394 Citrm Fruits Control measures have not yet been fully worked out. On account of the presence of this fungus, the state of Florida is now quarantined against the introduction of nursery stock or bud-wood from Alabama. Melanose and Stein End Rot (Phomopsis citri) These diseases, which are both caused by the same fungus, have been prevalent in Florida for many years. The fungus occurs in Australia, Jamaica, Porto Rico, and Algeria, but so far has not been found to exist in California. The disease lives normally and produces spores on dead twigs in citrus trees. The spores are washed by the rains over the surface of the fruit, causing, particularly on pomelos, peculiar brownish streaks known as tear-staining or melanose. These marks are nearly the same on leaves, stems, and fruit, and consist of raised areas of brown gum-filled cells forming dots, lines, rings, or irregular spots which greatly injure the general appearance of the fruit while not injuring the eating quality. Stem-end rot causes the fruit to drop, beginning with im- mature fruit in August and continuing till after the fruit has been sent to market. It even causes decay after the fruit has reached market. The softening begins at the stem end and is especially common on fruits which have scale insects about the stem end. It is more severe during a warm fall and winter, and infection seems to be more common in damp shady situations. Sound picked fruit can be infected by contact with diseased fruit. The fungus inhabits the soil under infected trees and the spores develop in spring and summer on dead twigs, bark, and on mummified fruits. The application of fungicides to the trees or disinfectants to the wash-water does not control the disease. The most successful method of control is to keep the trees carefully Diseases and their Control 395 pruned and free from all dead twigs, stubs, and mummified fruits. The prunings should not be plowed into the soil, but should be removed from the orchard and burned before the fungus has time to grow and produce spores upon this ma- terial. All diseased fruit which falls to the ground should be collected and destroyed. Careful culling at the packing- house and refrigeration in transit are aids to control. Also it is advisable to keep the trees as free as possible from scale insects. Nail-head Rud (Cladosporium herbarum var. ciiricolum) In Florida the nail-head rust is quite common, while it has not as yet been found in California. It is often called scaly- bark in Florida, but it is very distinct from the California scaly-bark, the cause of which has not yet been discovered. The disease appears on the twigs and small branches as slightly raised rusty spots, as implied by the name. The fungus also produces spots on the fruits which are hard, cir- cular, sunken, and more or less corky. Affected fruits color and drop prematurely. The spots due to this fungus are found only on sweet oranges. Various control measures have been suggested, such as top-working the trees to pome- los ; heading back and spraying with bordeaux, followed by an insecticide ; and carefully pruning out all dead wood. Scab or Verrucosis {Cladosporium citri) Citrus scab is another disease which occurs in Florida and other parts of the world but has not so far been found in California. The following description of scab is from the Florida Experiment Station Bulletin No. 108, page 41. " This disease, which is especially common on sour oranges and lemons, makes its appearance on the fruit as irregular 396 Citrus Fruits light brown or corky projections from the surfac(\ It is caused by a fungus which attacks the fruit or lea\'es when quite young. Its attack on sour oranges and lemons (and sometimes on Satsumas and grapefruit) often results in making them misshapen and unsightly. In severe attacks, projections of a dark gray to corky or even tan color will be seen extending out from the surface. The surface of the fruit between the warts is usually of a normal color. Often these irregular corky projections coalesce to form a large raised corky scab. In less severe attacks, especially when scab occurs on grapefruit and on tangerines (or rarely on sweet oranges), the warty irregular projections are wanting, and there will be seen more or less raised platform-like patches variable in shape and extent. The surface of the raised portion is finely scabbed or lightly scurf ed, as is seen in the case of thrips marks or silver scurf. In this milder form it can usually be distinguished from thrips marks or other forms of scurf by its being raised, but can be distin- guished with certainty only by the use of the compound microscope. " The scab can be completely controlled by the use of weak bordeaux mixture (3-3-50). Since (in Florida) the use of bordeaux on orange trees, however, kills the friendly fungi ^ and allows a rapid increase of scale insects or white-fly, this 1 It should be explained for the benefit of those not famiHar with eonditions in Florida that there are a number of Idnds of fungi wliich prey as parasites upon the scale insects and white-fly larvae and are thus of very great benefit to the citrus growers. Some of these friendly fungi occur in India and other places, but so far none have been successfully estabhshed in California, where the air is too dry perhaps for their success. In spraying with bordeaux for fungus diseases in Florida, the killing off of these friendly fungi has to be considered, for an application of bordeaux usually must be followed by an insecticide on account of the great sudden increase of scale insects. Diseases and their Control 397 spray is not recommended except when it is absolutely neces- sary. When it must be resorted to, a good insecticide should be used as soon as the scale insects begin to increase rapidly. Some of the harm from increase of scale insects may be pre- vented by spraying the bordeaux as much as possible only on the fruit, and keeping the spray off of the larger limbs and the inside of the tree where the friendly fungi may be left alive." Diplodin Rot of Oranges (Diplodia natalensis) A form of fruit decay which occurs in Florida and South Africa but has not so far been reported from California. H. S. Fawcett gives the following description of it in Florida Exp. Sta. Bull. 108, p. 46 : " In the early stage this rot shows as a patch about the stem end similar to stem-end rot. The discoloration becomes darker as the decay proceeds, and appears as dark wide bands corresponding to the di\'isions between the segments. The fruit becomes black as the decay advances and very light in weight. The rot often advances quickly through to the 'blossom' end, and a patch of discoloration shows there before all the peel is involved. The Diplodia rot often starts also in thorn punctures or similar injuries. It is usually accompanied by the exudation of a small amount of thin gum, or a considerable amount of amber-colored sticky juice. This amber-colored juice less frequently accompanies the stem-end rot. IVIany of the characteristics of the two rots are so similar that for practical purposes they may be classed together. The citrus fruits are much more resistant to Diplodia rot than to stem-end rot. Diplodia rot appears to be less common on immature fruits on the tree, and the fungus causing it is less parasitic. The same methods of treatment given for stem-end rot hold good for the Diplodia rot." 398 Citrus Fruits Red Blotch of Lemon It is in stored fruit alone that red blotch develops. It is often called "red rot" by packing-house men but as it is apparently not due to any parasitic organism the latter name is misleading. It is characterized by the rind shrinking and turning to a dark color in large spots or blotches. The discoloration is usually limited to one side of the fruit and gradually changes from rusty bronze to dark red and finally to black. On cross section, affected fruit shows the discolora- tion about the seeds, the central core, and along the parti- tions, while the vesicles appear normal. The disease does not spread among the lemons by contact. It is unusual for red blotch to develop in large amount in any one house, although the losses in the aggregate are large. It has been suggested that red blotch may be caused by sunburn or overheating of the lemons on the tree, but so far neither the true cause nor a remedy has been demonstrated. Yellow Spottiufi of Oranges In all the interior valleys of southern and central California and in Arizona it is the usual thing for oranges of all varieties to develop small bright yellow spots before the oranges are mature. Often these spots are very conspicuous on account of the contrast with the green rind. Usually all the oranges on the exterior of the trees and especially those near the ground show the spots. When the fruit colors naturally there is no longer any contrast and the spots are no longer visible to any but an experienced eye. As these spots do not damage the fruit for eating or for sale but little interest has been shown in determining the cause. They are probably due to the bites of some small insect such as a leaf-hopper, many species of which are common in the orchards. At Diseases and their Control 399 one time it was thought that these spots later developed into the brown spot of the Navel orange, but this has been shown not to be the case. Stem End Spot The California stem end spot of oranges is a very different thing from the stem end rot common in Florida aiid pre- viously described. It appears as small dried out and sunken spots immediately adjacent to the stem of the fruit and is most seri- ous on the Navel orange. It occurs only on fruit which is beginning to age. The cause has not been clearly demonstrated. Sometimes during wet weather, saprophytic fungi may grow on these dead spots, in which case the appear- ance of the fruit is injured and it is not safe to ship it to market. The remedy is to pick and ship the fruit earlier. Trunk Rot {Schizopyllum commune) The decay of the trunks of citrus trees due to this fungus is especially common in the moist coast region and in northern California. Where stubs have been left in careless pruning of the large limbs the spores gain entrance, and in time the white bracket-like fruiting bodies appear. The fungus is thought 400 Citrus Fruits not to be strongl}- parasitic on sound healthy tissue, hut once started it may cause dying l)ack of the wooch The disease may easily be prevented by paying proper attention to the •'^Uk.isJ B^ijar^^ ^30) in3 m j^^^ei W' M^j wr '^^J3^ m Fig. 13s. — Pruning stub on orange tree affected with Schizopyllum. disinfection of pruning wounds and by covering all large cuts with a suitable dressing. Inasmuch as the presence of this fungus indicates neglect, it reflects discredit upon the orchardist. There are several other kinds of fungi which have not been identified which, after getting started in sunburn cracks or Diseases and their Control 401 frost injuries, may cause a progressive decay of the wood of citrus trees. All these may be prevented by care and attention to injuries. When once well started it may require rather extensive tree-surgery to entirely rid the tree of the infection. • Galls and Knots Occasionally large galls are found on the branches of citrus trees in California. They are not common or very injurious, and the only remedy suggested is to prune them out. These galls may be due to the crown gall organism which produces similar galls on the roots of peach, almond, and other fruit trees. Crown gall has been produced on citrus trees experi- mentally by C. O. Smith of the University of California. Recently Florence Hedges ^ investigated a rather serious and contagious form of gall on citrus trees from the Island of Jamaica. The cause was discovered to be a fungus, Spha'rop- sis tumefaciens. All the galls so far found in California have been different and the contagious SplioBrojisis gall is not known to occur either in California or Florida, although common in Cuba. Black Pit of Lemon (Bacterium citriputeole) A serious blemish which occurs occasionally on tree-ripe lemons late in the spring. This trouble is apparently con- fined to southern California. It appears as large dark red or black spots, the surface of which is firm and markedly depressed below the general surface of the rind. The spots do not increase in size rapidly or progress into a general decay, but the appearance of the fruit is ruined. The cause ' "A Knot of Citrus Trees Caused by Sphceropsis tumefaciens " by Florence Hedges and L. S. Tenny, U. S. D. A. Bureau Plant Industry, Bull. No. 247, 1912. 2d 402 Citrus Fruits is a bacterium which gains access to the rind through thorn punctures. Apparently an abrasion is necessary before the bacteria can enter. The trouble may be prevented in three ways : pick the fruit before it becomes tree-ripe, grow thornless varieties, or protect the orchard by windbreaks. CHAPTER XXII CITRUS INSECTS AND THEIR CONTROL The number of insects which seriously attacls: citrus fruit trees in California is not large ; their lack in numbers, however, is more than offset by their aggressiveness and their ability to withstand control measures. While it is true that fumigation for scale and spraying for red spider or mites, if properly done, is supposed to kill all the in- dividuals on the trees at the time of treatment, yet in actual practice a few usually survive and later reinfest the trees, so that in the course of time remedial measures must be repeated . The financial loss due to the various citrus pests is large, the cost of control amounting to more than half a million dollars a year in southern California, according to a re- cent estimate. This does not take into account the secondary losses due to weakened trees, dirty fruit, and fruit scarred by thrips or mites. The state as well as the nation is spending large sums annually in studying citrus pests and in devising better methods of control, while in addition to this most counties employ a horticultural com- missioner and a corps of inspectors whose chief duty is to assist in controlling pests already established in the county and to prevent the introduction of foreign species. 403 404 Citrus Fruits The distribution of the various citrus insects in CaUfor- nia is greatly influenced by the dift'erent cHmatic conditions obtaining in the different parts of the state. The purple scale has so far not become established nor is the black scale serious on citrus trees in the hot dry air of the interior valleys. The red and yellow scales are both found in the San Joaquin citrus districts, although not in injurious num- bers, while the yellow scale alone is found in the Sacra- mento districts. Before the introduction of various in- sect pests into California from Florida, the general opinion prevailed that such insects would not thrive when taken from a humid into a comparatively arid climate. The fact that any particular insect has not so far become es- tablished in a given region must not be taken as sufficient evidence that it will not thrive when an opportiuiity to infest trees presents itself. At the present time, it is very encouraging to note the fact that in the better kept citrus orchards of the state it is often difficult to find specimens of certain insects for study. In some localities where red and yellow scale, mealy bug, or silver mite were once very abundant, it may now require a diligent search to locate a single individual, so effective has been the work of the inspectors and the application of remedial measures. A point which should be emphasized is the importance of keeping orchards and fence rows free from weeds which harbor scale. One of the worst offenders among weeds is the common nightshade (Solanum nigrum) which is so abundant throughout most of the state. Even after thorough fumigation of the trees has been accomplished, a few scales living on the nightshade will start a new infes- Citrus Insects and their ContrcA 405 tation, the blame for whicli is often unjustly charged to carelessness of the fumigators. For sake of convenience, insects are usually divided into two general groups, the biting insects and the sucking in- sects. The biting insects are those which bite or tear oflF pieces of the plant tissue and actually consume parts of leaves or the tissues upon which they are feeding. The sucking insect on the other hand pierces the tender plant with a slender proboscis or tube-like mouth-part and proceeds to extract the sap from the cells. All the scale insects, the mealy bugs, the plant lice, and the red spider have sucking mouth-parts, the thrips have mouth-parts fitted for both rasping and sucking, while the rose beetle, the orange tortrix, and the diabrotica are biting insects. A proper understanding of the manner in which an in- sect obtains its food is necessary before remedial measures can be intelligently applied. For biting insects, a stomach poison such as paris green or arsenate of lead should be used, w^hile for sucking insects, a solution or gas which kills by contact, such as lime-sulphur or kerosene emulsion or hydrocyanic acid gas, is necessarj^ A contact insecticide either fills up the breathing pores which are located along the sides of the body of the insect, thus suffocating them, or produces fatal irritation. The sucking insects are by far the most destructive and troublesome in citrus orchards as well as the most difficult to control. Black Scale (Saissrtia olece) The black scale is widely distributed over the earth, since like other scale insects, it is very easily carried from one 406 Citrus Fruits country to another on young nursery trees and ornamental plants. This scale is perhaps the most damaging insect Black scales on orange tw-ig. pest of the citrus districts in the Mediterranean region. The exact date of its introduction into California is not known. Citrus Insects and their Control 407 According to a report published in 1880, it was well es- tablished at that time. It is found in nearly all the counties of the state, although as a citrus pest it is troublesome chiefly in southern California, especially near the coast. In Los Angeles, Santa Barbara, and Orange counties it takes first rank among citrus insects, while in Ventura and San Diego counties it is given second rank. In Western Riverside and San Bernardino counties, it is also a serious pest, as is shown by the fact that 75 per cent of the insect control work in Riverside county in 1910 was directed against the black scale, although such a high percentage is unusual. The black scale injures the tree by sucking the sap. The greatest injury, however, is done indirectly by the sooty mold which accompanies the scale. The insect excretes copious amounts of a substance, known as honey-dew, which falls upon the leaves and fruit below. This furnishes a suitable medium for the growth of the sooty mold fungus (Mcliola caynellioB) which not only clogs up the breathing pores of the leaves and renders them incapable of performing their normal functions, but also forms a black coating over the fruit which necessitates thorough washing before the fruit can be packed for market. This washing is often of neces- sity so severe as to cause abrasions in the skin and a con- siderable increase in the amount of decay during transit to market. The size of the adult scale will average about one-seventh of an inch in length and not quite as broad. It may be dis- tinguished from closely related species by a plainly outlined letter H on the back of the full grown females. The color of the mature female is usually very dark, often jet black. The male scale is minute and is very seldom seen. When mature the male emerges from its pupal case as a winged insect. 408 Citrus Fruits The life history of the hhick scale varies in diflferent sections, but in general it is about as follows : Eggs are produced most abundantly in May, June, and part of July, the average number found under each scale being about eighteen hundred. In about twenty days the eggs hatch. At the end of a day or two the young insects make their way out from under the protecting mother scale, and crawl around for two or three days before settling down, the leaves and tender twigs offering the most suitalile feeding ground. Unlike the armored scales, the black scale is, up to a certain age, able to withdraw its sucking mouth-parts from the tissues and move to more favorable pasturage. This accounts for the fact that only a few mature individuals are seen on the leaves, while such large numbers are found on the branches. The yellowish half grown females are most common from about the middle of September to the middle of December, while during the spring and early summer months the dark adult scales are most abundant. Although there seems to be but one generation of the black scale during the year, it is not uncommon along the coast to find all stages at one time. It is this irregularity in the appearance of the young scales that makes the problem of control so difficult. The insect is naturally most susceptible to any destructive influence during the two or three days when it is crawling around searching for a suitable place to feed. The hot dry air of the interior valleys kills them off in large numbers and they are not able to establish themselves so readily as in the coast sections. The young insects may readily be seen crawling about over the leaves and stems, but a little observation will show that their powers of locomotion are very limited ; they are not able to crawl from one tree to another over the rough ground Citrus Insects and their Control 409 and must depend upon some other agency to carry them any considerable distance. Probably the most common agents for their dispersal are the ladybird beetles. These and other insects are often found with one or more young scales on their backs, and when the beetles fly to other trees, the scales are carried along to start new infestations. Birds are probably responsible for transporting young scale insects long distances, as the latter have ample opportunity to crawl upon the bodies of birds wliich are roosting in the trees or resting between flights. Man, however, has been mostly responsible for the wide distribution of the black and similar scales, especially by the shipment of promiscuous lots of nursery stock from one country, or one section to another. In the orchard the yoimg scale is very liable to be distributed during the ordinary operations of cultivation, prun- ing, picking, and hauling to market. In some packing-houses the precaution is taken of fumigating all lug-boxes as they are emptied. They are loaded directly into the wagons from the fumigating room, to be taken back to the orchard. In this way the danger of introducing scale into a clean or- chard by means of lug-boxes is reduced to a minimum. There are several natural enemies of the black scale in California. Among these, the most important is the parasite, ScufcUista cyanca, which was introduced from South Africa in 1900 and is now found in most of the districts where black scale abounds. The Scutellista is an egg parasite and the larvpe feed only on the eggs which are deposited by the mature black scale. In some cases all the eggs under one scale may be consumed, but in other cases the parasites come to maturity mth a greater or less number of eggs untouched. Even if the eggs are completely destroyed in the parasitized scales, there are usually a sufficient number of female scales which are not parasitized to carry on the Infestation. While 410 Citrus Fruits the Scutellista aids materially in reducing the numbers of the scales, it cannot be depended on alone for the effective control of the pest. Another egg parasite, Tomocera caJifornica, is found in some sections but is not nearly so effective as the preceding. There are at least four ladybird beetles as well as an internal parasite of the male insect which also prey upon the black scale. Where only a few trees around the house are infested or only young trees require treatment, spraying with distillate emulsion or kerosene emulsion is recommended. The emul- sion is made as follows : Kerosene 1 gallon Soap (laundry) h pound Water 15 gallons The soap should first be dissolved in about a gallon of hot water, and while still hot, add the kerosene, away from the fire. The mixture may then be emulsified by churning it back and forth for several minutes until it becomes of the consist- ency of cream, when it is diluted to make the sixteen gallons. The oil should be thoroughly emulsified before being used, as free oil in the mixture is apt to cause serious injury to the bark of young trees. Where the soil is sandy the con- centration of the spray material which runs down the trunks and reaches the soil may cause injury at the collar. In such cases the oil-saturated soil should be removed from about the collar and replaced by a few handfuls of fresh soil. This should be done three or four hours after the spray has been applied. Fumigation is usually more effective, however, in control- ling l)lack scale, as the gas penetrates to all parts of the tree and the fumigation properly done kills both the mature and half grown scales. Citrus Insecfs and their Cuiifrol 411 The Red or Orange Scale {Chrysomphalm aurantii) The red scale is found along with the black scale in the southern coast counties, where it is a serious enemy of citrus Fic. 140. — The red scale on orange. trees. It takes first rank as a pest in San Bernardino and Riverside counties, while in Orange and Los Angeles counties it takes second place. It was found in California in 1878, and the origin of that infestation was traced to Australia, al- 412 Citrus Fruits thou«^ vs -IS 16 --l€ -\-l7 +/7 --/7 Fig. 150. — Method of marking fumigating tent. (After Woglum.) lating the dosage for a tree was mostly guesswork, the operator gauging the size of the tree by eyesight and basing the dosage upon previous experience. Such methods sometimes produced fairly good results but in Insect Control by Fumigation 437 general the work was very irregular and poor. The tents now in use are plainly marked, as shown in the accom- panying diagram, the measurement:? being marked in feet from the center of the tent. When the tent is enfolding a tree, the distance over it can readily be determined by adding the number that touches the ground on one side of the tree to the number that touches the ground on the opposite side. The two auxiliary lines are necessary, as in actual practice the middle line may not fall over the middle of the tree but to one side, and in such a case the line nearest the center is used for measurement. The two side lines may be either three or four feet from the middle line. Equipment of Tents For elevating the tents over the trees, either poles or derricks are used, the latter being necessary only for very tall trees. Fourteen- and sixteen-foot poles are most commonly used. One end is sharpened to prevent its slipping on the ground. To the other end is fastened a rope about three feet longer than the pole. Sometimes rings are attached to the edge of the tent, and these are slipped over the ends of the poles; it is usually more satisfactory, however, to double-lap the edge of the tent over the ends and secure it firmly by a half-hitch of the pulling ropes. Generators Another part of the outfit is the set of earthen jars or containers called generators. These are made especially for the purpose, usually without covers, and of two gallon capacity. The two gallon size is preferred, as it is large 438 Citrm Fruits enough to accommodate 20 ounces of cyanide in medium sized lumps without boihng over. When trees requiring more than this amount are to be fumigated, two or more generators may be used under one tent. Generators with Hds are desirable as the lids not only aid in throwing the gas outward but prevent spattering of the acid on to the tent. Acid holes in tents cause serious leakage, reduce efficiency, and necessitate frequent and expensive patching. So far, however, no lids manufactured have proved entirely satisfactory. The most imi)roved type of generator has the outside of the bottom flat as usual but the inside of the bottom is cup-shaped, with the depres- sion in the center. This is a great advantage when work- ing wdth very small trees as it assures a more thorough decomposition of the small quantity of cyanide used for each charge. Still another part of the fumigating outfit is the supply cart in which are carried the cyanide, sulfuric acid, water, scales for weighing the cyanide, graduated glass for meas- uring the acid and water, rubber gloves, dosage schedules, and lantern. There is on the market an excellent supply cart designed especially for this purpose which is highly desirable where funds will permit, although simpler and less expensive carts answer very well. Cyanide Potassium cyanide was used in all fumigation work until recently. Now, however, sodium cyanide is used exclu- sively for the reason that it is not only cheaper but will supply a larger amount of hydrocyanic acid gas. The Insect Control by Fumigation 439 cyanide should be kept dry in storage and exposed to the air as little as possible, since moisture decomposes it. Acid Sulfuric acid for fumigating should be about 66° Baume, which is approximately ninety-three per cent pure. It is sold either in iron drums containing about 2000 pounds or in glass carboys of about ten gallons capacity. On account of its corrosive action glass or earthenware containers are used for distributing the acid in the field. A replaceable copper or glass pipe fitted into the bottom of the container on the supply cart is con- nected with a rubber tube bearing a large pinch-cock for regulating the flow. Care must be used in handling the acid as it will quickly burn wherever it comes in contact with the skin ; for this reason, rubber gloves are advisable. It has been found that the 1-1 1-2 formula recom- mended by the Bureau of Entomology is most economical and produces a complete reaction. This formula calls for 1 fluid ounce of commercial sulfuric acid, 1^ ounces (avoirdupois) 129 per cent sodium cyanide, and 2 fluid ounces of water. The water is measured and placed in the generator first, then the acid is measured and poured into the water. Lastly, when everything is in readiness, the cyanide is weighed and placed in the solution, the operator quickly retreating and closing the tent. The addition of water to the acid is very important. It dilutes the acid and raises the temperature of the mixture, thus accelerating the evolution of gas. The by- product resulting from the reaction is sodium sulfate, 440 Citrus Fruits a solid. The water dissolves this solid as fast as it is formed and prevents it from forming a coating over the lumps of cyanide and retarding the reaction. If sufficient water is not used, the sulfate will solidify, thus "freez- ing" the residue, as it is called. This necessitates extra labor in emptying the generators. When concentrated acid is diluted with an equal amount or more of water, nearly pure hydrocyanic acid is given off. If the con- centrated acid is used without water another gas known as carbon monoxide is formed. The cyanide should always be used in lumps about the size of a hen's egg. If finely powdered cyanide is used, the reaction is too violent and endangers the operators. If the cyanide should be dissolved in water before the acid is added, the reaction will be so violent as to be classed as an explosion, greatly endangering the operators and injuring tents and trees. Paper bags are no longer used for depositing the cyanide in the generators. Cakes of compressed cyanide weighing one ounce each are now on the market, and have proven very satisfactory and convenient. Under proper conditions the evolution of gas will have been completed in about five minutes. Operation An orchard requiring fumigation should be thoroughly examined regarding the slope of the land, length of tree rows, convenience to water supply, smoothness of the ground over which the supply cart is to be draw'n, and similar factors which influence the ease of operation. A tent and a generator are unloaded at each tree and the Insect Control hy Fumigation 441 tents unfolded on the side away from tlie direction in which they are to be moved, ('oniniciiciiiff at one end of the row, the tent pullers fasten the two poles to the edge of the tent in the maimer previously described, place the shari)ened ends of the poles on the ground at the sides of the tree opposite the trunk, and holding the bottom of the pole to the ground with one foot, pull on the rope. When the poles are so elevated that they no longer slip, each puller moves away from the bottom of the pole and out from the tree so that the continued pulling will bring the edge of the tent over the tree and down on the other side. When thus covered, the edge of the tent should be kicked in so that it hangs evenly all around and does not inclose unnecessary space. After the tree has been fumigated the required length of time, the tent can be pulled over on to the next tree by this same process with- out lowering it entirely to the ground. The next step in the process is the calculation of the approximate space inclosed by the tent and the proper dosage to use. Schedules given on pages 450 to 453 indicate the proper dosages for the principal citrus in- sects which require treatment. Knowing the distance over the tree (found as previously directed) and the cir- cumference of the tent near the base, one will have no difficulty in using the tables. The number found at the in- tersection of the vertical and horizontal rows on the table indicates the number of ounces of cyanide to be used. With the ordinary outfit of five men, the work may be distributed as follows : two men handle the tents, a third takes the measurements and calls them out to the men at the supply cart, who immediately consult the dosage Insect Control hi/ Finmgdtion 443 table, weigh out the eyanide, and measure the sulfuric aeid and water into the generator. While the cyanide man lifts the edge of the tent, the other places the generator underneath. The former then puts in the cyanide and droj)s the tent. While the chemi- cal men are thus applying the proper dosage to one tree, measurements are being made on the next and the process is repeated until the entire row is fumigated. Fumigation gangs are usually equipped to handle about thirty tents at a "throw," as they call it. When kept busy these 30 tents are "thrown" or moved once in every forty-five minutes or once every hour as the variety of scale will determine. Thus, except with very large trees, the number of trees fumigated per night does not vary according to the size of the trees, the difference simply being a difference in the time the men have to rest between throws, as all must be left over the trees a stated period of time. As a rule fumigators, when the nights are favor- able, begin work about 5 p.xM., and if the night is not too cool or a fog arises, will work till G a.m., giving a twelve- hour night if an hour is taken off at midnight for lunch and rest. Thus with twelve-hour nights and throws every hour, a gang operating 30 tents will fumigate about 3^ acres provided the trees are planted regularly twenty feet apart each way. Fumigating in short rows, on contours, or in rough ground is slower, of course. Season of Finnigatioji The time of year at w^hich fumigation is done depends upon two factors, the life-stages of the scale insect and 444 Citrus Fruits i z < Q 2I£J12,2I2I |g,S{lS!glSI iSil^-SlgiS Sg M M 1 £ M 1 M 1 gg M ] M IgllllllllliMl^lMII SIIMIISIMMISIMII glMIIISIIIMIS MM SMMM5MMMS MM fS 1 1 1 1 1 1 ;f^ 1 1 1 1 1 1 ^ M M 1 ^MIMIieMMMieMMI ;:MMM^MMM^MMI r^MMMr^MMM^MMI ^mmmsmmmsmmi i§ 1 1 ! 1 1 1 s g 1 1 1 1 1 i 1- i ^ ai?:; § 1 1 1 1 1 1 s 1 i 1 1 1 1 5 i:£ '- ^ ai?; S MMISMMIIS |S,'^iiiE;lg U M M 1 S M M 1 1 S r^[3ii:l2l2 g|llii|SIIIMIg |:2lEI'^l2t2 s§i 1 1 1 1 iig| 1 1 iiJr;2iiSi::!'^!iii:i2 SI M M M § M i:jI2I i |n;i:2rsil:l2 S M M M S M l^i^l S |2i::i2l2i;^ Si M M M g M 1 l::i2Jl § I2l:i:i:2l2l2 S M 1 1 1 1 S I^PI2l"i2l S 121212:1212 S « I-I-I2- =15 r^l2l2l::!2 S M M ! 1 S r^l^h'-l2 z:| 5 |::!2i2l;^l:: 3 M M M 3 m^'r-iSI 3 | = I£JI£!I2I:2 SMI l'"!'^! 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Most of the fumiga- tion in Cahfornia is carried on between the hitter ])art of August and the middle of January, as during these months the black scale is most successfully reached and the fruit is large enough to escape the injury which sometimes occurs when it is young and tender. As previously men- tioned, fumigation is ordinarily done at night when the air is cool. Occasionally the work may be done on dark cool days, but day work is quite apt to result in burned foliage and fruit. Fumigation is not advisable when the temperature falls below 38° F. or rises above 65° F. as the operator runs some risk of injuring the trees if the work is done much outside these limits of temperature. Another natural factor which operates against successful work is a strong breeze, w^hich may either hasten the escape of the gas from the tent or greatly injure the side of the tree on which the gas becomes densest. Cases of serious injury to trees which were said to have resulted from fumigation when the foliage was wet have been frequently reported. Careful experiments along tbis line, on the other hand, show that the presence of moisture on the trees can be ignored so far as direct action of the gas is con- cerned. Due, however, to the fact that the tents become so heavy and retain so much more of the gas on a wet than on a dry night, it is advisable to stop fumigating after the foliage and tents become thoroughly damp. The insect pests against wdiich fumigation is generally directed are the black, purple, red, yellow^, and citricola scales. The susceptibility of these scales to the gas varies more or less, and accordingly several dosage schedules have been worked out. Experiments by Woglum in finnigating Insect Control by Fumigation 449 for the purple scale demonstrated that the best results were obtained by one and one-half ounces of potassium cyanide to every one hundred cubic feet of air space under the tent, the fumigation continuing for one hour, by the end of which practically all gas had escaped. This is designated as dosage schedule A and upon this the other schedules are based. The three-quarter schedule for 129 per cent sodium cyanide is the one almost univer- sally used at the present time. Dosages For the purple scale, dosage schedule No. f sodium cyanide should be used with an exposure of one hour. P^or red and yellow scales, dosage schedule No. f is recommended with an exposure of forty-five minutes to one hour. For black scale, the dosage varies. When the insects are in the young and tenderer stages, f of schedule A is sufficient, and it is during these stages that fumigation is advisable. Dosage schedules A for sodium cyanide and No. 110 per cent A are reproduced on pages 446, 447 and 444, 445 respectively. They have been tested out experimentally in actual field operations by Woglum. Copies of these schedules printed on cardboard may be secured from the U. S. D. A. Bureau of Entomology, or from dealers in fumigators' supplies. While using the dosage sched- ule in the orchard, it should be framed with a clear celluloid or glass cover, as otherwise it will soon become so worn and dirty as to be illegible. 2g 450 CitriLs Fruits New Woodirorth Dosage Table C. W. Woodworth has recently suggested a new way of calculating dosage which appears to have the advantage of greater simplicity and accuracy. Dosage Table — Sodium Cyanide Relative Size Dose Purple Scale Dose Black Scale 64 ft. 40 oz. 20 oz. 61 ft. 46 oz. 18 oz. 58 ft. 32 oz. 16 oz. 55 ft. 28 oz. 14 oz. 52 ft. 24 oz. 12 oz. 50 ft. 20 oz. 10 oz. 47 ft. 18 oz. 9 oz. ISIiiiinmm Dose 44 ft. 16 oz. 8 oz. 41 ft. 14 oz. 7 oz. Leakage 38 ft. 12 oz. 6 oz. .40% 36 ft. 10 oz. 5 oz. 33 ft. 9 oz. 4|oz. 30 ft. 8 oz. 4 oz. .35% 28 ft. 7 oz. 3i oz. 26 ft. 6 oz. 3 oz. 24 ft. 5 oz. 2ioz. .30% 21ft. 4 oz. 2 oz. 19 ft. 31 oz. If oz. 16 ft. 3 oz. Uoz. .25% 2A oz. li oz. 2 oz. 1 oz. .20% li oz. 1 oz. 1 oz. ioz. .15% |oz. \ oz. .10% (Relative size equals distance over plus 1 for each 5 ft. of difference between measurements.) Lmed Control by Fuiiur/afion 451 In explanation of this new system Prof. Woodworth has submitted the following : " The possibility of adding to the distance over an amount dependent on the difference between the two measurements which will indicate the proportionate size of a tent gives us what we may call the ' relative size ' of the tent. If the proportions of a tent remained constant, the difference over could then be taken as the relative size. Since the distance around always equals or exceeds the distance over, we may select as standard a tent with these two measurements equal. The amount to be added to this to allow for wider and shorter tents is one-fifth of the difference between the two measurements. Thus a tent 20 X 30 would have a relative size of 22, and should have a dose equal to that of a tent 22 X 22. " The ado])tion of this plan of relative sizes makes it possible to present a table of dosage in a very simple form, and to make the adjustments for different degrees of leakage also \'ery easy. " In the foregoing table the first column gives the rela- tive sizes corresponding to the series of doses shown in the second and third columns suitable for tents having the average leakage of 25 per cent. " The adjustment for leakage is equally simple. Oppo- site each per cent given in the table is the minimum dose. Xo matter how small the tree, if a tent leaks 40 per cent, the dose for purple scale should not be less than 12 oz. Indeed, it is unwise to attempt to fumigate with a tent of this degree of leakage except when big enough to hold a sufficient body of gas without its })eing too concentrated at the time of generation for the safety of the tree." 452 Citrufi Fruits Costs Cyanide costs by the ton about 22 cents a pound. Con- tract fumigators usually furnish the cyanide at ;30 cents a pound, including the acid for generation. The sulfuric acid alone costs about 1^ cents a pound. Laborers receive pay by the hour. The rate is usually 35 cents an hour, while the foreman receives 50 cents an hour. Most trees fumigated require between five and eighteen ounces of cyanide. A supply cart completely equipped may be had for about $35. Two gallon generators cost about 45 cents each. Tents cost from $12 to $50 each, according to size. The thirty-six foot tent costs ready-made from $25 to $30 each. The cost of thirty 45-foot tents of special 7-ounce drill, together with the other equipment necessary to complete the outfit, will cost about $1400. Recently a fumigating machine has been invented which quickly generates the gas in a large metal drum by mixing a water solution of cyanide and acid. The gas is discharged directly into the tent through a four-inch hose. The use of this machine makes generators unnecessary and prevents all acid holes in the tents. It is now being wddely experimented with. CHAPTER XXIV VARIOUS ORCHARD PESTS AND THEIR CONTROL There are several pests other than insects with which citrus growers are apt to have to deal. A knowledge of the habits of animals such as gophers and ground squirrels is necessary before intelligent methods of repression can be adopted. Recently the citrus root nematode has at- tracted much attention, and a rather detailed account of its habits and life history will no doubt prove of quite general interest. Citrus Nematode (Tylenchulus semi penetrans) As stated in Chapter XXI this worm has been suggested as the cause or one of the causes of mottled-leaf. On account of the popular interest in the nematode and the great diver- sity of opinions regarding it, space is given to a more or less detailed account. The data here presented has been largely condensed and adapted from Cobb.^ This citrus nematode was first noticed by J. R. Hodges of Covina, California, in 1912, and first mentioned in print by B. R. Jones.- A preliminary report was later published by E. E. Thomas of the University of California. ' N. A. Cobb, "Citrus-root Nematode," Journal of Agri- cuUural Research, Vol. II, No. 3, June, 1914, pp. 217-230. 2 Los Angeles County Hort. Com. Bull. No. 1, 1913, pp. 72- 73. 453 454 Citrus Fruits This species of nematode is found only on the roots of citrus trees although it occurs in all parts of the world where citrus trees have been grown for any length of time. The worms are very minute, being barely visible to the unaided eye. The males are smaller than the females and probably do not attack citrus roots. In fact, it is thought that the males do not take food while in the perfect stage. The eggs are large and thin shelled, and are deposited one at a time in batches of twelve to twenty or more, and are sometimes incased in gmiimy matter. The eggs hatch in a day or two into colorless larvs which make their way to the nearest citrus root to which the females attach themselves in more or less well defined groups. These groups are very quickly scattered along the fine fibrous feeding roots in enormous numbers. The effect is to sap the vitality of the tree and kill the feeding roots. The movements are slow and weak and the worms cannot migrate through the soil to any great distance. The females possess an oral spear with which they force the head end into the tissues of the root. That part of the body within the root enlarges somewhat so that it is impos- sible for them to withdraw. They remain fixed for the rest of their lives, although the exposed part of the body may be moved back and forth. The food consists of sap and pro- toplasmic cell contents. The entire life cycle occupies from six to eight Aveeks. A predaceous nematode of large size (]\IononcJms payil- latus) has been foimd to occur also in the soil about citrus roots. The Mononchus preys regularly upon the males and larvae of Tylenchulus, swallowing them whole. To what extent the Mononchus may be able to control the citrus nematode is not at present known. The citrus nematode affects the different stocks about Variouft Orchard Pests and their Control 455 equally. It has so far been found in abundance on the sour, sweet, and trifoliate oranges and on pomelos. " There can be no doubt that Tylenchulus scini penetrans is an injurious parasite. There is conclusive evidence that it kills the feeding roots of citrus trees. The roots die either as a direct result of the attack of this parasite or of the attack of other organisms following in its wake ; in other words, the nematode is a primary cause of the death of the feeding roots. Many cases have come under observation in which it was apparent that, had it not been for the nematode, the roots would have remained in a healthy condition. The evidence along these lines is of the same character as that which is relied on in demonstrating injuries due to insects and other macroscopic parasites. "The extent of the damage which may properly be charged up against this parasite is a different matter, and it will be necessary to collect evidence along this line for several years before a final statement can be made. Up to the present the data obtained indicate unquestionably that the investi- gations should be continued." The citrus nematode is very readily distriliuted from place to place on the roots of imrsery stock, and this is especially true when the trees are balled for shipment. The question as to just how much importance to place upon inspection and quarantine in connection with this parasite cannot be an- swered at the present time. In order to be on the safe side it is well for buyers to specify that the trees be free from nematodes. Control measures such as injecting carbon bisulfide and lime water into the soil are l)eing widely ex- perimented with, but so far without any very promising re- sults. Vaile^ has shown that nematodes are killed by sub- mersion in hot water at a temperature of 120° F. for ten 1 Annual Rpt. Ventura County Hort. Com. 1913, p. 10. 456 Citrus Fniits minutes. This treatment did not kill the roots entirely, al- though some of the fine feeding roots were injured. This is not considered important because when trees are trans- planted with bare roots they put out new feeding roots anyway. It is possible that some such method of treatment may soon be devised by which infested nursery stock may be freed from the pest. The Pocket Gopher (Gcomys hursnriu.s) Gophers often cause serious damage to citrus trees by girdling young trees at the surface of the ground and by chew- ing the bark from the crown roots of older trees. They are especially troublesome in orchards near alfalfa fields in sec- tions where open ditches are used for irrigation. Gophers will run for considerable distances over the surface of the ground at night, and entering an orchard without warning begin to dig their runways. The runs extend for long dis- tances underground and are vexatious nuisances when irri- gating. Gophers may be controlled both by poisoning and by trapping. In trapping use a small wire spring trap and set it delicately so it will spring easily. Then open the run under a recently made pile of fresh dirt and insert the trap, pushing it well back into the run. If the run goes both ways, put in two traps to make sure. Then close up the holes with grass or sod so that just a little light can enter. The gopher will soon notice the light, and in attempting to close the opening will be caught. It is well to attach a long string to the trap to prevent their being lost if pulled for some distance back into the hole. Any attempt to drown a gopher Viy turning irrigation water into the hole will not succeed unless the entire surface of the ground can be flooded as is possible in alfalfa fields. Strychnine is probably the most effective and safest poison Varions Orchard Pests and their Control 457 for general use. A sirup poisoned with strychnine is very easily prepared and will he found very effective. It is made according to the following formula recommended by the U. S. Bureau of Biological Survey: "Dissolve an ounce of strychnia sulfate in a pint of boiling water. Add a pint of thick sugar sirup and stir thoroughly. The sirup is usually scented by adding a few drops of oil of anise, but this is not es.sential. If preserved in a closed vessel, the sirup will keep indefinitely." This quantity will poison about thirty pounds of shelled corn or grain, preferably corn. The grain should be soaked in water overnight and then soaked for several hours in the poisoned sirup. The dry strychnine may also be used by introducing a very small quantity on the point of a knife into carrots, beets, sweet potatoes, entire raisins, or prunes. Such poisoned bait is then placed carefully in the freshly open holes, or in the runways. There are many prepared gopher poisons on the market which may be pur- chased if one does not care to go to the trouble of mixing the strychnine as directed. The use of carbon })isulfide for killing gophers is recom- mended where the soil is moist and the burrows not too ex- tensive. In dry soil, the gas escapes too rapidly to make its use effective. The bisulfide may be poured over a btuich of cotton waste or other material and this pushed cjuickly into the burrow, which should be closed at once. Since carbon bisulfide is highly inflammable a very common method of ap- plication is to ignite the cotton waste after it is placed in the burrows as deeply as possible ; the gases produced by ignition are poisonous and seem just as effective a killing agent as the liquid bisulfide. On account of the danger of explosion to the operator and the liability of starting grass fires, the use of bisulfide by ignition is not so advisable as by the former method. Special injectors for forcing the l)isulfide 458 Citrus Fruits into the Inirrows are on the niiirket and are more effeetive than the hand method. Reeently a new method of attack has been (Hscovered which is said to work well where only a few gophers have to be dealt with. An automobile is placed over the hole and a short hose attacked to the exhaust, the other end being inserted in the gopher hole and packed with moist soil. After turning an extra amount of luV)ricating oil into the cylinders for the purpose of making a smoky gas, the engine is started. If smoke is emitted from any hole in the vicinity it is promptly plugged. A few minutes of this treatment naturally pro- duces a condition fatal to the gopher. Ground Squirrrlfi (CiteUus hrrchryi) These animals overrun California, occurring by millions in the interior valleys, where they destroy large quantities of grain, almonds, and dried fruit. They may do great dam- age to citrus orchards and nurseries but, unlike the gopher, their depredations are largely confined to orchards situated near grain fields or brush land. Railroad embankments, canal banks, and roadsides are favorite places for squirrel burrows. The animals live mostly on grain, nuts, acorns, and weed seeds, but during the rainless summer and fall, when the green herbage dries up, they are apt to visit citrus trees and gnaw the bark. A few squirrels may quickly ruin a large number of trees when the young trees have just been planted out. Ground squirrels may be poisoned in the same way as gophers, poisoned barley or wheat being most commonly used for this purpose. Whole barley threshed but still retaining its rough outer husk will not be eaten by birds, so it should always be used in this form. The following formula and di- rections for preparing poisoned barley are suggested : Various Orchard Pests and their Control 459 Whole barloy 20 pounds Vinegar I5 pints Strychnia sulfate 1 ounce Honey 1 pint Cyanide of potassium I5 ounces Eggs 1 dozen Pulverize the strychnine in the vinegar and see that it all dissolves. Dissolve the cyanide in a little water. Beat the eggs thoroughly. Mix all the ingredients together and stir well before adding to the barley. Stir at intervals during the next few hours and dry before using as it will mold if put away wet. Grain coated with poison is more effective than grain soaked in poison for the reason that much of the grain being gathered, carried into the burrows and stored for winter use is not immediately effective. When the grains are coated with poison, enough will be absorbed by the cheek pouches during transit to produce death. Another very effective poison during the dry season is halved ripe cull oranges, upon the cut surfaces of which strychnine has been smeared. CHAPTER XXV BIBLIOGRAPHY OTHER BIBLIOGRAPHIES Waters, Cakkik S. "Citrus Fruits and Their Culture," a Bibliog- raphy classified according to subjects. Published 1913 by San Bernardino Free Public Library. Ferrari, E. Extensive Bibliography of the Lemon. Bol. Abor. Ital. 5 (1909), pp. 145-80. Savastano, L., and Pahrozzani, A. List of about Fifty Articles on Citrus in European Literature. Annals Royal Italian Ex- periment Station for Agr. and Fruit Culture, Vol. 1, 1911. Cook, A. J. "Bibliography of Citrus." In " California Citrus Cul- ture," Calif. State Com. Hort., 1913. Hume, H. H. "American Citrus Literature." In Chapter XIV, "Citrus Fruits and Their Culture," 1907. REFERENCES TO LITERATURE DEALING WITH PAR- TICULAR FRUITS Orange Growing in United States Craw, A. "Working Over Old Orange Trees." Pacific Rural Press, May 9, 1885. Garey, T. A. "Orange Culture in California." San Francisco, 1882. Jackson, J. R. "Notes on Oranges." Garden. Copied in U. S. D. A. Yearbook, 1887, p. 56. LuMMis, C. F. "Oranges 250 Years Ago." The Land of Sunshine, Vol. XVI, Feb., March, and April, 1902. 461 462 Bibliography Spalding, VV. A. "The Orange, Its Culture in California." River- side, 1880. Skinner, L. B. "Orange Culture in Florida." Proc. Am. Pom. Soc. 1911, pp. 70-6. Whitney, J. P. "Educational Orange Growing." Sunset Maga- zine, Vol. 70, pp. 161-70, Aug. 1906. Wallace, T. C. "The Cultivation of Oranges." Pacific Rural Press, Oct. 24, 1908. Saunders, Wm. "Notes on Orange Culture." Rpt. of U. S. Dept. of Agr. 1886, p. 687. Hart, E. H. "The Orange." The American Fruit Culturist, 1908, p. 621. Onderdonk, Gilbert. "The Orange in Texas." Texas State Dept. Agr. Bui. 9, p. 7. Manville, a. H. "Practical Orange Culture." Jacksonville, Ashmead Bros., 1883. Powell, E. P. "The Orange, Another of our P"'irst Families." Independent, Vol. 60, p. 1089, May, 1906. Meyers, W. A. "How to Grow and Cultivate an Orange Grove in Louisiana." La. State Hort. Soc. Proc. 1906, p. 71. Brown, E. "Oranges in Northern California." Scientific Ameri- can, Vol. 88, pp. 138-9, Feb. 1903. [Carnes, E. K.] "Development of the Orange Industry in Cali- fornia." Natomas News, Vol. 3, No. 1, March, 1913. Horgan, H. V. "Growing Oranges under Tents." Country Californian, Vol. 1, pp. 717-19, 7.50, Dec. 1905. WiCKSON, E. J. "The Orange in Northern and Central California." San Francisco Chronicle, Jan. 1, 1903. Reprinted by State Board of Trade. Williamson, Robert. "Orange Growing in Central and Northern California." Pacific Rural Press, Vol. 39, p. 2, Jan. 4, 1890. Kinney, A. "The Orange, History, Analyses, Varieties." Pacific Rural Press, March 21, 1885, p. 282. GuiNN, J. M. "From Cattle Range to Orange Grove." Pacific Monthly, Oct. 1910. Bibliography 463 MoREMEN, M. S. "Present Condition and Treatment of Orange Groves." Florida Agr. Exp. Sta. Bui. 33, 1896. Bennett, J. E. "Roofing Over Orange Orchards." Current Literature, Vol. 27, pp. 146-7, Feb. 1900. Orange Growing in Foreign Countries Ferrarius, J. B. "The Hesperides or About the Golden Apples. Their Culture and Use. In Four Books." Rome, 1646. Pye, Thomas. "History and Culture of the Orange." Dept. Agr., New South Wales, Bui. 1, 1890. Alderton, G. E. "Treatise and Handbook of Orange Culture in Auckland, New Zealand." Wellington, 1884. Moody, J. F. "The Cultivation of the Orange." Dept. of Agr., West Australia, Bui. 34, 1912. Trabut, L. V. "L'Oranger en Algerie." Direction de I'agriculture gouv. gen. Algerie, Bui. 44, 1908. Freeman, L. R. "The Orange in the West Indies." Pacific Rural Press, June 21, 28, and July 5, 1913. Bell, H. H. "Cultivation of Oranges in Dominica." Imp. Dept. of Agr., Barbados, Bui. 37, 1905. Abella, a. "Orange Culture in Montevideo." Min. Indus. (Uruguay) Insp. Nac. Gan. y Agr., Bol. 7 (1913), p. 48. [Anonymous.] "Orange Growing in Lower California." Pacific Rural Press, Nov. 22, 1884. Amoore, H. E. "Japanese Orange Growing." Pacific Rural Press, No. 19, 1887, p. 411. Orchard, P. W. "A Study of the Orange Districts of Spain." The Florida Grower, Oct. 11, 18, 25, 1913. Newcomer, E. J. "Oranges at Seville." Pacific Rural Press, June 7, 1913. Shamel, a. D. "Orange Growing in Brazil." Pacific Rural Press, Jan. 10, 1914, p. 41. Bertoni, G. T. "The Oranges of Paraguay." An. Rpt. Estacion Agron. de Puerto Bertoni Para 1911 y 1912, p. 195. 464 Bibliography Shepstonp:, H. J. "Jaffa Orange Ciilturo." World's Work (London), Vol. 17, pp. iyy-2():3, Jan. 1011. EiSEN, G. "The Jaffa Orange in Egypt." Calif. Cultivator, Jan. 23, 1913, p. 100. [Anon.] "The Orange Imlustry of Palestine." Hacherouth, No. 20, 1913. Aaronsohn, a., and Soskin, S. "The Orange Groves of Jaffa." Tropenpflanzer, Vol. 6. Aaronsohn, A. "Jaffa Oranges in Palestine." U. S. D. A. Bureau Plant Industry, Bui. 180, 1910, p. 2o. [Anon.] "An Orange Farm." South African Agr. Journ., Feb. 1913, p. 176. McIlwaine, R. "The Possibilities of Rhodesia as a Citrus Growing Country." Dept. Agr. Rhodesia, Bui. 2, Feb. 1908. Farmer, C. E. "Citrus Fruit Trees from Seed to Grove." Dept. Agr. Rhodesia, Bui. 153, Aug. 1913. "Citrus Fruits in Rhodesia." Dept. Agr. Rhodesia, Bui. 164, Dec. 1913. "Rhodesian Citrus Fruit." Dept. Agr. Rhodesia, Bui. 166, Dec. 1913. McIlwaine, R. "Some Citrus Growing Experiences in Rhodesia." Dept. Agr. Rhodesia, Bui. 182, June, 1914. Varieties Chapman, C. C. "Orange Varieties and Their Respective Merits." Rpt. 28th Calif. Fruit Growers Convention, 1903, p. 163. Saunders, Wm. "Washington Navel Orange, Its History and Pollen Production." U. S. D. A. Yearbook, 1887, p. 640. Van Deman, H. E. "History of the Washington Navel Orange." American Garden, June, 1888, p. 231. Hart, E. H. "History of the Various Navel Oranges under Culti- vation." Semi-Tropical Planter (San Diego), May, 1887. Van Deman, H. E. "The Navel Orange, Another Chapter in Its History." Senii-Tropical Planter, June, 1887. Bibliography 465 "Bahia or Washington Navel Orange." Rpt. U. S. Dept. Agr., 1886, p. 267. "History of the Washington Navel Orange." U. wS. D. A. Year- hook, 1887, p. 640. "History of the Introduction of the Washington Navel." Rural New Yorker, June, 1899. CoiT, J. Eliot. "The History of the Washington Navel or Bahia Orange." Calif. Cultivator, April 18, 1912. Chap.man, C. C. "Introduction of the Australian Navel." History of Orange County, 1911, p. 74. Reasoneu, p. W. "The Navel Oranges in Florida." American Garden, April, 1888, p. 135. Mills, J. W. "Origin of the Golden Nugget Navel Orange." Calif. State Bd. Hort. Rpt. 1902, p. 256. Taylok, W. a., and Gould, H. P. "The Thomson Orange." U. S. D. A. Yearhook, 1911, p. 436. Hume, H. H. "The Surprise Navel Orange." Proc. 29th Am. Pom. Soc. 1905, p. 169. Earle, S. F. "The Navel Orange in Cuba." Calif. Cultivator, Jan. 1, 1914. Saunders, W.m. "History of Hart's Late or Hart's Tardiff Orange." U. S. D. A. Yearbook, 1887, p. 640. [Anon.] "Origin of the Valencia Late Orange." Pacific Rural Press, Sept. 18, 1909, p. 180. Williams, P. F. "The Satsuma Orange." Alabama Exp. Sta. Bui. 157, 1911. Taber, G. L. "The Satsuma Orange." American Garden, 1890, p. 590. Saunders, W.\i. "The Satsuma Orange." U. S. D. A. 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"V^ariation in the Branches of the Navel Orange." Calif. Cultivator, July 6, 1911, p. 4. [Anon.] "Do Different Buds on the Same Orange Tree Produce Like Fruit? " Calif. Cultivator, March 13, 1913. Belling, J. " Polyembryony of the Orange." Florida Sta. Rpt. 1908, p. cix. Mills, J. W. "Improvement of the Orange." Rpt. Calif. State Bd. Hort. 1902, p. 255. Insects Affecting Oranges Hubbard, H. G. "Insects Affecting the Orange." U. S. D. A. Div. of Entomology, 1885. AsHMEAD, W. H. "Orange Insects." Jacksonville, Fla., 1880. Sasscer, E. R. "The Cork-colored Orange Tortricid." Journal Econ. Ent., June, 1911, p. 297. Gandara, Guillermo. "Enfermedades y Plagas Del Naranjo." Mexico. Sec. deFomento. Callejon de Bettemitas, No. 8, 1910. Jones, P. R., and Horton, J. R. "The Orange Thrips." U. S. D. A. Bureau of Entomology, Bui. 99, part 1, 1911. QuAYLE, H. J. "The Orange Tortrix." Journal Econ. Ent., Oct. 1910, p. 401. Hekrera, a. L. "The Morelos Orange Worm." Journal Econ. Ent. 1908, No. 3, pp. 169-74. [Anon.] "Trypeta Ludens in Mexico." Calif. State Hort. Com. 1905. MouLTON, Dudley. "The Orange Thrips." U. S. D. A. Bureau of Ent. Tech. Series, No. 12, part VII, 1909. 468 Bihl log ra pill/ CoMSTOtK, J. H. "The Angular-Winged Katydid On Orange." U. S. D. A. Rpt. Sec. of Agr. 1880, p. 249. Dew, J. A., and Wolp% F. A. "The Satsuma Orange, Its Insect Pests and Diseases." Bui. 1, Insecticide Dept. Van Antwerp's Seed Store, Mobile, Ala. Orange Diseases Reed, -J. H. "Black Rot of the Navel Orange." Calif. Cultivator, Vol. XVII, No. 11, p. 160, 1901. Pierce, N. B. "Black Rot of Navel Orange." Calif. Cultivator, Vol. XVII, No. 12, p. 181, 1901. "Black Rot or Navel Rot of Orange." Bot. Gaz. Vol. 33 (1902), No. 3, pp. 234-5. Fawcett, H. S. "Black Rot of the Navel in Florida." Florida Exp. Sta. Rpt. 1911, p. Ix. Amundsen, E. O. "Black Rot of the Navel Orange." Calif. State Com. Hort. Monthly Bui., Vol. 2, No. 5, May, 1913. Fawcett, H. S. "Stem End Rot of the Oranges." Florida Exp. Sta. Rpt. 1911, 1912. "Diplodia Rot of Oranges." Florida Exp. Sta. Rpt. 1911. "Three Fungus Enemies of Orange Trees." Proc. Am. Pom. Soc. 1911, p. 190. "The Scaly Bark Disease of the Orange." Florida Exp. Sta. Rpt. 1907, p. xliii. "Orange Scab or Verrucosis." Florida Exp. Sta. Rpt. 1911. CuRTiss, A. H. "The Prevention of Orange Rust." Florida Exp. Sta. Bui. 2, 1888. Webber, H. J. "Sooty Mold of the Orange and Its Treatment." U. S. D. A. Div. Veg. Phys. & Path. Bui. 13, 1897. Powell, G. H. "The Decay of Oranges While in Transit from Cali- fornia." U. S. D. A. Plant Ind. Bui. 123, 1908. Smith, R. E. "The Soft Spot of Oranges." Bot. (iaz. Vol. 24 (1897), No. 2, pp. 103-4. Messenger, C. B. "Orange Dropping and Its Causes." Calif. Fruit Grower (1896), No. 19, pp. 450-1. Bibliography 460 Webber, H. J. "Melanose of the Orange." Florida Farmer and Fruit Grower, 7 (1896), p. 419. Underwood, L. M. "Diseases of the Orange in Florida." Journal of Mycology, Vol. \U, No. 1, Sept. 10, 1891, p. 63. Scribner, F. L. "Orange Leaf Scab." U. S. D. A. Rpt. 1886, p. 120. Smith, R. E. "Brown Spot of the Orange." Calif. Exp. Sta. Rul. 203, 1909, p. 47. CoiT, J. Eliot. "The Brown Spot of the Navel Orange." Proc. Soc. Hort. Sci. 1910, p. 62. Galloway, B. T. "Gum Disease or Foot-Rot of the Orange." U. S. D. A. Div. Bot. Bui. VIII, 1889, pp. 51-4. Smith, R. E., and Smith, E. H. "Orange Diseases." In Calif. Sta. Bui. 218, 1911. The Lemon Holt, L. M. "Lemon Culture for Profit." Proc. Pom. Soc. of Southern Calif. 1892, p. 30. Powell, G. H. "The American Lemon Industry." U. S. D. A. Yearbook, 1907. Powell, G. H., and Chase, E. M. "Italian Lemons and Their By-Products." U. S. D. A. Plant Industry, Bui. 160, 1909. [Anon.] "History of the Lemon Rate Case." Calif. Cultivator, Aug. 29, 1912. Powell, G. H., and Wallschlaegek, F. O. "The California Lemon Industry." Citrus Protective League, Bui. 9, Jan. 1913. Powell, G. H. "The Italian Lemon Industry." Citrus Protective League Circular 10, Jan. 1913. [Anon.] "Cost of Producing Lemons in California." Citrus Protec- tive League, Brief of Facts Presenteil to Ways and Means Com- mittee of Congress. Jan. 20, 1913. Cheney, A. S. "The Lemon Industry in Sicily." U. S. Consular Rpt. 1908. Works, J. D. "The Tariff on Lemons." Speech in U. S. Senate, Julv 24, 1913. 470 Bibliography Garcelon, G. W. "Fifteen Years with the Lemon." Calif. State Board of Hort. Pamphlet, 18<)1. Newcomer, E. J. "Italian Lemon Culture." Calif. Cultivator, May 29, 1913. Kimball, F. A. "Lemon Culture and Lemon Curing." Rpt. Calif. State Bd. Hort. 1888. Conger, O. H. "Lemon Culture." Rpt. Calif. State Bd. Hort. 1889. Tenney, W. a. "Ventura Lemon Culture." Overland Monthly, Vol. 60, pp. 150-7, 1905. Ferrari, E. "Extensive Bibliography of the Lemon." Bol. Abor. Ital. 5 (1909), pp. 145-80. Lelong, B. M. "Varieties of the Lemon." Calif. State Bd. Hort. Rpt. 1888, p. 39. Kimball, F. A. "Lemon Culture." Proc. Am. Pom. Soc. 1897, pp. 95-9. Blanchard, N. W. "The Lemon and Its Treatment." Pacific Rural Press, \'ol. 39, p. 378, 1890. Teague, C. C. "Curing and Shipping Lemons." Calif. Fruit Grower, July 11, 1903. Allen, W. J. "Curing the Lemon." Dept. Agr. New South Wales, Farmers' Bui. 47, 1912. Harwood, N. S. "Growing American Lemons." World's Work, Vol. 5, pp. 3315-22, April, 1903. Tylor, a. R. "Gray Mold of Lemons." Calif. Cultivator, Feb. 1, 1912. Smith, R. E., and Smith, E. H. "Brown Rot of the Lemon." Bot. Gaz. Vol. 42, pp. 215-21, Sept. 1906. Smith, R. E. "Brown Rot of the Lemon." Calif. Exp. Sta. Bui. 190, 1907. Fawcett, H. S. "Tear Staining of Lemons." Calif. Com. Hort. Monthly Bui., June, 1913, p. 560. "Two Fungi as Causal Agents in Gummosis of Lemon Trees in California." Calif. Com. Hort. Monthly Bui., Aug. 1913. Bibliography 471 "Treatment for Gummosis of Lemon Trees." Calif. Cultivator, July 24, 1913. Smith, C. O. "Black Pit of Lemon." Phytopathology, Vol. Ill, No. 6, Dec. 1913. Rolfs, P. H. "Lemon Scab." Florida Grower, June 6, 1914. The Lime Watts, Francis. "Lime Cultivation in the West Indies." Imp. Dept. Agr. for West Indies, Pamphlet No. 72, pp. 136, 1913. NiCHOLLS, H. A. A. "The Lime." In Chapter VI, "Text-Book of Tropical Agriculture." [Anon.] "The Lime Tree and Its Products." Nature, Vol. 79, p. 22, 1908. TiMEHRi. "The Lime Industry of Dominica." 18S3. Tempany, H. a., and Jackson, T. "Lime Industry of Antigua." West Indian Bulletin, Vol. 12. [Anon.] "Feeding and Manurial Value of Lime Skins." Agricul- tural News, Vol. 11, p. 288. Ballou, H. a. "Notes on Lime Cultivation." West India Bui., Vol. 11, p. 93. Brooks, A. J. "Development of the West Indian Lime Fruit." West Indian Bui., Vol. 12, p. 506. Sands, W. N. "British West Indian Limes in New York." West Indian Bui., Vol. 11, p. 153. Jones, G. A. "The Keeping Qualities of Lime Juice." Agricul- tural News, Vol. 11, p. 180. Watts, F., and Jones, J. "Citrate of Lime and Concentrated Lime Juice." West Indian Bui., Vol. 9, p. 159. Mandarin Oranges Hume, H. H. "The Mandarin Orange Group." Florida Exp. Sta. Bui. 66, 1903. Shinn, C. H. "The Japanese Oranges." The American Garden, Vol. ll,pp. 333-6, June, 1890. 472 Bihlio(jrai)hji Wester, P. J. "Mandarin Oran Lelong, B. M. "The Pomelo in California." Calif. State Bfl. Hort. Rpt. 1894, p. 63. Baker, C. F. "The Grapefruit in Southern California." Rpt. Proc. 39th Calif. Fruit Grow. Convention, 1911, p. 81. Hume, H. H. "Pomelos." Florida Exp. Sta. Bui. 58, 1901. Boyle, H. H. "Notes on Siamese Pomelos." Phil. Agr. Rev., Vol. VII, No. 2, Feb. 1914. Baker, C. F. "Siamese Seedless Pomelos." Am. Breeders Mag., Vol. IV, No. 4, Dec. 1913. [Anon.] "Siamese Seedless Grapefruit." U. S. Daily Consular and Trade Rpt., Aug. 28, 1911, p. 925. Harriss, H. "Grapefruit." Bui. Dept. Agr., Jamaica, n. s.. Vol. 2, No. 6, Jan. 1913, p. 166. Boyle, H. H. "The World's Best Pomelo." Phil. Agr. Rev., Vol. 5, No. 11, Nov. 1912, p. 614. Ward, C. W. "The Grapefruit Game and How to Play It." Out- door World and Recreation, Vol. 48, No. 3, Feb. 1913. MoTT, J. "The Pomelo, Shaddock, or Grapefruit." American Garden, Vol. 11, p. 715, Dec. 1890. Morris, D. "Grapefruit and Shaddocks." Garden and Forest, Vol. 9, 1896, p. 163. Hume, H. H. "Anthracnose of the Pomelo." Florida Exp. Sta. Bui. 74, 1904. The Kximquat Hume, H. H. "The Kumquats." Florida Exp. Sta. Bui. 65, 1902. [Anon.] "Citrus Japonica." Pacific Rural Press, March 5, 1887, p. 205. Chapin, L. p. "Kumquats." Good Housekeeping, Vol. 52, pp. 479-81, April, 1911. Bibliography 473 The Citron Ferrari, E. "History and Relationships of the Citron." Atti. R. 1st Incoragg. Napoli, 6. ser. 7 (1909), p. 21. Contains a good bibliography of Citron. Richardson. "A Chapter on Citron." Pacific Rural Press, March 31,1883, p. 284. Calhoun, J. J. "California Should Crow Citron." Orchard and P^arm (San Francisco), April, VM'A. [Anon.] "The Home of the Citron." Rural Califoniian. March 1905, p. 91. [Anon.] "Citrous in Mogador." Gardeners' Chronicle, 1884, 2 p. 601. [Anon.] "Citron of Commerce." Pacific Rural Press, Vol. 39 p. 244, March 8, 1890. (Fruiting at Riverside.) [Anon.] "Citron." Pacific Rural Press, Vol. 40, p. 3')2, Oct. 25 1890. Sturtevant, E. L. "Citron." Mem. Tor. Rot. Club, \'ol. 1, No 4, p. 158, 1890. [Anon.] "The Troon or Tabernacle Citron." Gardeners' Chronicle Nov. 8, 1885, p. 601. WiCKSON, E. J. "Candied Citron." Pacific Rural Press, Nov. 2 1907, p. 275. REFERENCES TO LITERATURE DEALINCi WITH THE CITRUS FRUITS IN GENERAL Miscellaneous References Ferrarius, J. B. "The Hesperides." 1646. Macfayden. "Citrus of Jamaica." In Hooker's Bot. Misc., Vol. 1, p. 295, 1830. Targioni, D. a. "Citrus Fruits." Journal Hort. Soc, London, Vol. 9, p. 171, 1855. 474 Bibliography Gallesio. "History of the Citrus." English translation in appen- dix to "Orange Culture," by T. W. Moore. De Candolle, a. 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Bureau Plant Ind. Cir. 46, Dec. 1909. BoNNS, W. W. "Results of Experiments with Citrus Root-stocks." Calif. Cultivator, Dec. 25, 1913. Taber, G. L. "Citrus Trifoliata verstis Sour Orange as a Stock." Exp. Sta. Record, Vol. XIV, p. 441, 1902. Cutter, J. E. "Citrus Stocks — Sour versus Sweet." Proc. Pom. Soc. South. Calif. 1892, p. 13. Van Demax, H. E. "Relative Merit of the Various Stocks for the Orange." U. S. D. A. Div. Pom. Bui. 4, 1891, p. 21. [Anon.] "Influence of Lemon Stock on Quality of Oranges." Calif. Cultivator, Feb. 23, 1911 and continued in subsequent numbers. Bernard, A. "Citrus Triptera as a Grafting Stock." Revue Horticole, Vol. SO, p. 140, 1908. Swingle, W. T. "Citrus Trifoliata in Relation to Citrus Culture." Proc. Am. Pom. Soc. 1911, p. 218. Wolf, F. A. "A Field Method for Distinguishing between Certain Orange Stocks." Alabama Exp. Sta. Circular 17, July, 1912. WiCKSON, E. J. "Citrus Trifoliata in California." Pacific Rural Press, June 20, 1907. Citrus Breeding Webber, H. J. "Complications in Citrus Hybridization caused by Polyembryony." Bot. Gaz. Vol. 29, 1900, p. 141. "New Citrus Fruit Creations of the Department of Agriculture." U.'S. D. A. Yearbook, 1904, p. 221. "New Citrus and Pineapple Productions." U. S. D. A. Yearbook, 1906, p. 329. "Present Status of Citrus Breeding." Proc. Am. Pom. Soc. 1907, p. 5. Swingle, W. T. "Some New Citrus Fruits." Am. Breeders' Mag. Vol. IV, No. 2, 1913. 480 Bihllodrapli!/ Swingle, W. T. "Citrus Breeding Experiments." In article on Crop Improvement. U. S. 1). A. Plant Ind. Circular 116, 1913. "Variation in First Generation Hybrids (Imperfect Dominance) : Its Possible Explanation through Zygotaxis." IV Confer- ence Internat. de Genetique, Paris, 1911, pp. 381-394. White, O. E. "Swingle on Variation in F 1 Citrus Hybrids and the Theory of Zygotaxis." Am. Nat., Vol. 48, No. 567, 1914. Shamel, a. D. "A Study of the Improvement of Citrus Fruits through Bud Selection." U. S. D. A. Plant Ind. Circular 77, 1911. "A Study of Bud Selection in Citrus Fruits." Proc. 39th. Calif. State Fruit Growers' Convention, 1911, p. 89. "Breeding Citrus Fruits." Calif. State Com. Hort. Monthly Bui. Vol. 1, No. 9, p. 441,1912. "Good and Bad Oranges and Orange Trees." Pacific Rural Press, June 13 and 20, 1914. "Bud Selection in Citrus Fruits." Pacific Rural Press, Jan. 31, 1914. Vaile, R. S., and Reed, F. "Citrus Breeding Discussions." CaHf. State Hort. Com. Monthly Bui. Vol. 1, No. 9, p. 479, 1912. Norton, J. H. "Variations in the Productivity of Citrus Trees." Calif. Cultivator, March 6, 1913. WiCKSON, E. J. "Improvement of Citrus Fruit Varieties." Am. Breeders' Assoc. Rpt. 1907, Vol. 3, p. 271. Babcock, E. B. "The Improvement of Citrus Fruits." University of Calif. Journal of Agr. Vol. 1, No. 7, Feb. 1914. Vaile, R. S. "Improvement of Citrus Stock through Bud Selec- tion." Pomona Calif. Journ. Econ. Bot. Vol. 1, Sept. 1911. Kraus, E. J. "Bud Variation in Relation to Fruit Markings." Oregon Crop Pest and Hort. Rpt. 1913, p. 71. CoiT, J. E. "The Relation of Asexual or Bud Mutation to the Decadence of California Citrus Orchards." Proc. 37th Calif. State Fruit Growers' Convention, 1910, p. 32. CoiT, J. E. "Budding Wood." Calif. Cultivator, Apr. 25, 1912. Bibliography 481 Hahtin, E. H. "The Ultimate Orange." Pacific Rural Press, Vol. 40, Aug. 16, 1S90, p. 140. Barrett, O. W. "Natural Citrus Hybrids." Phil. Agr. Rev. Vol. 5, No. 6, p. 334, 1912. Emerson, R. A. "The Possible Origin of Mutations in Somatic Cells." Am. Nat. Vol. 47, p. 375, 1913. Savastano and Parrozzani. "Some Natural Hybrids of Citrus Fruits." Annals Royal Italian Station of Agr. and Fruit Culture, Vol. 1, 1911. Also contains a bibliography of European citrus literature. Savastano, L. "Nomadic Albinism in some Orange Trees." Annals Royal Italian Station Agr. and Fruit Culture, Vol. 1, 1911. Kerner and Oliver. "Citrus Bizzaria a Graft Hybrid." In " Nat. Hist, of Plants," Vol. 2, p. 569. Trabut, Dr. "L'Hybridation des Citrus: Une Nouvelle Tangerine 'La Clementine.'" Revue Horticole, 1902, p. 232. Andre, Ed. "Oranger Hybride de Montanbau." Revue Hor- ticole, 1905, p. 243. Citrus Soils and Root Si/stems Reed, J. H. "Penetration of Orange Tree Roots." Calif. Culti- vator, 14 (1900), No. 21, pp. 321-3. "Root Systems in the Orange Orchard as Affected by Irrigation, Cultivation, and Fertilization." Pacific Rural Press, 61 (1901), No. 1, pp. 4-5. Lipman, C. B. "Humus Discussion, Cover Crops." Calif. Culti- vator, Dec. 4, 1913. "Essentials in the Management of California Soils." Calif. Com. Hort. Monthly Bui. Vol. 3, No. 1, Jan. 1914. "The Use of Lime and (Jypsum on California Soils." Calif. Exp. Sta. Circular 111, 1913. Call, A. F. "How to Handle Citrus Soils." Calif. Cidtivator, Feb. 5, 1914. HiLGARD, E. W. "Acidity of the Root Sap of Citrus Trees." Calif. Exp. Sta. Rpt. 1895-97, pp. 181-3. 2i 482 Bibliography HiLGARD, E. W. "Marly Subsoils and the Chlorosis or Yellowing of Citrus Trees." Calif. Exp. Sta. Circular 27, 1900. "Hardpan and Cultivation." Calif. Exp. Sta. Report, ISOS- 1901, p. 149. ClL\SE, E. "Investigation of Citrus Subsoils." Pror. oTth Calif. State Fruit Growers' Convention, 1910, p. 61. LouGHRiDGE, R. H. "Alkali Tolerated by Oranges." Calif. Exp. Sta. Bui. 133, 1901, p. 17. Paine, C. R. "Soil Treatment in Citrus Orchards." Calif. Culti- vator, March 6, 1913. Bristol, W. M. "Sand on Heavy Citrus Soils." Calif. Culti- vator, March 6, 1913. Mills, J. W. "The Use of Dynamite in Orchard Planting." Calif. Cultivator, Nov. 20, 1913, p. 500. Irrigation LouGHRiDGE, R. H. "Distribution of Water in the Soil in Furrow Irrigation." U. S. D. A. Office Exp. Sta. Bui. 203, 190S. Etchevery, B. a. "The Selection and Cost of a Small Pumping Plant." Calif. Exp. Sta. Circular 117, 1914. "Irrigation and Cultivation of Orchards." Dept. Agr. British Columbia, Victoria, Bui. 44, 1912. WiCKSON, E. J. "The Water Needs of Citrus Trees." U. S. D. A. Farmers' Bui. 116, 1900. Tait, C. E. "Cost of Irrigating Citrus Fruits." Pacific Rural Press, June 3, 1911. "Irrigation of Citrus Orchards." U. S. D. A. Office Expt. Sta. Bui. 236, 1911. Kritzer, W. H. "Definitions and Equivalents for Irrigation and Hy- draulic Computations." Pacific Rural Press, July 27, 1912, p. 28. Adams, F. "Irrigation Resources of California and their Utiliza- tion." U. S. D. A. Office Exp. Sta. Bui. 254, 1913. Whitney, D. J. "Overhead Irrigation in the Citrus Grove." Pacific Rural Press, July 13, 1912. Blhli()(jr(i})li!/ 483 WoEHLKE, W. V. "The Water Savers." The Outlook (New York), March 25, 1910, Vol. 94, p. 659. Wallace, T. C. "Irrigating Oranges." Pacific Rural Press, Oct. 31, 1908, p. 276. Forbes, R. H. "Irrigating Citrus Trees in Alkali Soil." Arizona Exp. Sta. Bui. 44, 1902, p. 171. Koethen, E. L. "Irrigation, the Citrus (Growers' Catechism." Pacific Fruit World, May 20, 1911, p. 4. Stanley, F. M. "Irrigation of Citrus Groves." Florida Grower, May 17, 1913. Fertilization HiLGARD, E. W. "FertiHzers for California Orange Trees." Pacific Rural Press, Nov. 7, 1908, p. 294. W'EBBER, H. J. "Fertilization of the Soil as Affecting the Orange in Health and Disease." U. S. D. A. Yearbook, 1894, pp. 193-202. Colby, G. E. "Ingredients withdrawn from the Soil by Citrus Fruits." Exp. Sta. Record, Vol. 5, pp. 5-89. "Effect of Fertilizers on Fruit of Navel Oranges." Calif. Exp. Sta. Rpt. 1895, pp. 172-7. Floyd, B. F. "Problems in Citrus Nutrition." Fh)rida Exp. Sta. Rpt. 1911. Wright, George. "Fertilizing Citrus Fruits." Calif. Cultivator, Oct. 30, 1913. Webber, H.J. "Fertilizer Experiments with Citrus Fruits." Calif. Cultivator, Dec. 11, 1913. Call, A. F. "Fertihzing California Citrus Orchards." Calif. Cultivator, Feb. 19, 1914, p. 228. Painter, E.O. "Fertilizers for Citrus Fruits." Proc. 32d Session Am. Pom. Soc. 1911, pp. 54-9. Murtado, D. J. "Fertilizing Oranges in Spain." Calif. Culti- vator, Dec. 4, 1913. Chapman, A. C. "Fertilization of Orange Orchards." Calif. State Bd. Hort. Rpt. 1888, p. 150. 484 Bibliography Wallace, T. C. "Fertilizing Orange Orchards." Pacific Rural Press, Nov. 7, 1908. Blair, A. W. "Experiments on Citrus Fertilization." Florida Exp. Sta. Rpt. 1911. WiCKSON, E. J. "Oranges and Potash." Pacific Rural Press, Nov. 20, 1909, p. 323. Hilgard, E. W. "Effect of Citrus Culls on Soil." Calif. Culti- vator, June 6, 1912. Robertson, G. R. "Citrus Culls as a Fertilizer." Calif. Culti- vator, June 15, 1911, p. 208. Cover-Crops and Green Manuring GoEZE, E. "Early Green Manuring of Oranges." Gardeners' Chronicle, July 27, 1867, p. 785. Davy, J. B. "Lupines for Green Manuring in California." Calif. Agr. Exp. Sta. Rpt. 1897-98, p. 203. McKee, R. "Orchard Green Manure Crops in California." U. S. D. A. Plant Ind. Bui. 190, 1910. Messenger, C. B. "Buckwheat for Humus." Calif. Cultivator, June 4, 1914, p. 680. Call, A. F. "Green Crops in the Citrus Orchard." Calif. Culti- vator, Feb. 12, 1914, p. 196. Waterbury, G. W. "Cover-Crops in Citrus Orchards." Calif. Cultivator, Jan. 15, 1914. Mertz, W. M. "Citrus Cover-Crops." Calif. Cultivator, Jan. 8, 1914, p. 36. Geraldson, G. "Green Manuring." Calif. Cultivator, Oct. 5, 1911, p. 314. LiPMAN, C. B. "Green Manuring in California." Calif. E.xp. Sta. Circular 110, 1913. "The Function of Cover-Crops." Orchard and Farm (San Fran- cisco), Jan. 1914, p. 201. Adamson, J. E. " Cover-Crops for Citrus Fruit." Pacific Rural Press, Sept. 20, 1913. Bibliography 485 Norton, J. H. "Citnis Cover-Crops." Calif. Cultivator, Jan. 27, 1910. KoETHEN, E. L. "The Best Citnis Cover-Crop." Pacific Fruit World, June 17, 1911. Whitney, D. J. "Advantages of Alfalfa in Orchards." Pacific Rural Press, Dec. 13, 1913. LiPMAN, C. B. "Citrus Cover-Crops." Proc. 39th Calif. State Fruit Growers' Convention, 1911, p. 124. Piper, C. V., and McKee, R. "Vetches." U. S. D. A. Farmers' Bui. olo, 1912. Varieties — Botany Swingle, W. T. " Eremocitrus, a New Genus of Hardy Drouth-Re- sistant Citrous Fruits from Australia." Journ. Agr. Research, Vol. 2, No. 2, May, 1914. Swingle, W. T., and Kellerman, Maude. "Citropsis, a New Tropical African Genus Allied to Citrus." Journ. Agr. Re- search, Vol. l,No. 5, 1914. "Citrus Ichangensis, A Promising, Hardy New Species from Southwestern China and Assam." Journ. Agr. Research, Vol. 1, No. l,Oct. 10,1913. Parish, S. B. "Botanic View of the Orange." Proc. 37th Calif. Fruit Growers' Convention, 1910, p. 21. Andre, Ed. "Oranges Monstrueuses." Revue Horticole, 1900, p. 423. [Anon.] "Ringing Oranges." Scientific American, Dec. 14, 1912, p. 515. Cutter, J. E. "Varieties of Citrus Fruits." Calif. State Bd. Hort. Rpt. 1894, p. 250. Lelong, B. M. "New Varieties of Citrus Fruits." Calif. State Bd. Hort. 1891. [Anon.] "New Citrus Varieties." Pacific Rural Press, Vol. 41, p. 21, Jan. 10, 1891. 486 Bibliography Chemistry — Judging Colby, G. E. "Analyses of California Oranges." Calif. Exp. Sta. Bui. 93, p. 6, 1891. "Analyses of California Oranges and Lemons." Calif. Exp. Sta. Rpt. 1893-94, pp. 240-56. "Comparison of Shipping Navel Oranges from Northern, Southern, and Middle California." Calif. Exp. Sta. Rpt. 1898-1901, p. 244. "Composition of Citrus Culls." Calif. Exp. Sta. Rpt. 1898, p. 259. PiCKELL, J. M., and Earle, J. J. "Analyses of Oranges." Florida Exp. Sta. Bui. 17, 1892. Collision, S. E. "Sugar and Acid in Oranges and Grapefruit." Florida Exp. Sta. Bui. 115, 1913. Henry, A. M. "The Chemical Composition of Florida Oranges." Florida Dept. Agr. Quar. Bui. Vol. 23, No. 2, April, 1913. Rose, R. E. "Immature Citrus Fruit." An. Rpt. Florida State Chemist, Dec. 31, 1913. "Report of Commission Appointed to prepare Immature Citrus Fruit Standard." Florida Dept. Agr. Quar. Bui. Vol. 22, No. 4, Oct. 1, 1912. "Analyses of 280 Samples of Oranges." Florida State Chemist, Aug. 15, 1912. "Immature Citrus Fruit : Laws, Rules, and Regulations." Pub- lished by state printer, Florida. Not dated. "When is an Orange Mature and Wholesome?" Address before Assoc. Am. Food, Drug and Dairy Officials, Portland, Maine, July 16, 1914. "Details of the Acid Test Law in Florida." Florida Grower, Sept. 13, 1913. "Florida Green Fruit Law in Detail." Florida Grower, Aug. 23, 1913. Bahadur, Rana. "Composition of Fibrous Part of Japanese Orange." Univ. Tokyo, Col. Agr. Bui. Vol. VII, No. 1, 1906. SouTHERST, W. F. "Sugar Content of Oranges." Calif. Culti- vator, May 18, 1911, p. 612. Bibliography 487 Bancroft, A. L. "Where is the Orange the Sweetest?" Pacific Rural Press, July 8, 1911, p. 25. Van Deman, H. E. "Judging Citrus Fruits." Proc. Am. Pom. Soc. 1889, p. 145. Hume, H. H. "Judging Citrus Fruits." Citrus Fruits and their Culture, p. 155, 1903. "Judging Citrus Fruits." Proc. 23d Session Am. Pom. Soc. 1891, pp. 152-6. Cutter, J. E. "Scale for Judging Citrus Fruits." Calif. State Com. Hort. Rpt. 1889, p. 365. [Anon.] "Judging Citrus Fruit." Rural Californian, Dec. 1910, p. 364. Shamel, a. D. "Rules for Judging Citrus Fruits." Calif. Culti- vator, May 15, 1913. (See also June 5, 1913, p. 694 for judging trees in the orchard.) [Anon.] "Citrus Standard Score Card." Pacific Rural Press, Jan. 10, 1914, p. 42. Pruning CoiT, J. E. "The Pruning of Citrus Trees." Calif. Cultivator, Oct. 21, 1913. Englehardt, J. p. "The Pruning of the Washington Navel Tree." Proc. 37th Calif. State Fruit Growers' Convention, 1910, p. 97. Paine, C. R. "-Pruning to Improve the Orange." Proc. 28th Calif. State Fruit Growers' Convention, 1903, p. 169. "Orange Pruning." Calif. Cultivator, Jan. 22, 1904, p. 75. "Renovation of the Orange Tree by Systematic Pruning." Proc. 37th Calif. State Fruit Growers' Convention, 1910, p. 28. "Pruning out the Australian Type." Calif. Cultivator, May 16, 1912. "Systematic Pruning of the Orange Tree." Calif. Cultivator, May 16, 1912. Whitney, D. J. "A Change in Orange Pruning." Pacific Rural Press, Aug. 3, 1912. "Pruning Navels — Wild Wood." Pacific Rural Press, Jan. 17, 1914. 488 Bibliography Whitney, D. J. "Right Pruning and Novel Quality." Orchard and Farm (San Francisco), May, 1914, p. 2. Call, A. F. "Pruning Citrus Trees." Calif. Cultivator, Feb. 12, 1914, p. 197. Salle, J. W. "Pruning Citrus Trees." Calif. State Bd. Hort. Rpt. 1888, p. 211. Little, F. A., and Rumsey, C. E. "Pruning Citrus Trees." Rural Californian, March, 1909, p. 84. Williams, E. A. "The Pruning of Citrus Trees." Rural Cali- fornian, March, 1910, p. 89. TowT, C. W. "Citrus Tree Surgery." Univ. Calif. Journ. Agric. Oct. 1913. Bristol, W. M. "Pruning the Orange." Pacific Rural Press, May 29, 1909. Wallace, T. C. "Pruning Orange Trees." Pacific Rural Press, Nov. 14, 1908. KoETHEN, E. L. " Propping Citrus Trees." Pacific Rural Press, Oct. 26, 1907. Stiles, H. C. "Lemon Pruning in California." American Garden, Jan. 1891, p. 47. Williams, E. A. "Hints on Pruning Orange Trees." Pacific Rural Press, March 12, 1910. Leffingwell, C. W., Jr. "Pruning the Lemon Tree." Calif. Cultivator, No. 13, 1900, pp. 193, 199, and 200. Allen, R. C. "Pruning the Lemon Tree." Pacific Rural Press, Vol. 60 (1900), No. 13, p. 197. Lewis, E. S. "Shaping Lemon Trees." Calif. Cultivator, Aug. 28, 1913, p. 198. CoiT, J. E. "Dressings for Wounds of Citrus Trees." Calif. Culti- vator, Feb. 13, 1913. "Pruning Frosted Citrus Trees." (^alif. Exp. Sta. Cir. 100, June, 1913. Hodges, R. E. "Delayed Pruning Saved Frosted Citrus Trees." Pacific Rural Press, July 11, 1914. Bibliography 489 Curing — Storing — Sweating — Packing Teague, C. C. "Curing and Marketing Lemons." Proc. 28th Calif. State Fruit Growers' Convention, 1903, p. 63. SiEVEus, A. F. and True, R. C. "Keeping Quality of Lemons." Pacific Rural Press, June 19, 1909. "Some Factors Affecting the Keeping Qualities of American Lemons." U. S. D. A. Plant Ind. Cir. 26, 1909. "A Preliminary Study of the Forced Curing of Lemons as Practiced in California." U. S. D. A. Plant Ind. Bui. 232, 1912. Hart, J. H. "Precooling of Perishable Freight." Engineering Mag., Vol. 36, pp. 288-9, 1908. Stubenrauch, a. V. "The Relation of Handling to Decay in Calif. Navel Oranges in 1910-11." U. S. D. A. Plant Ind. July 13, 1911. Call, A. F. "Sweating Citrus Fruit." Calif. Cultivator, March 5, 1914, p. 292. Williams, L. B. "The Coloring of Oranges and Lemons by the Sweating Process." Proc. 37th Calif. State Fruit Growers' Convention, 1910, p. 104. Bigelow and Gore. "The Ripening of Oranges." Journ. Am. Chem. Soc. Vol. XXIX, No. 5, May, 1907. "Coloring Green Oranges." Ruling No. 133 U. S. Board of Food and Drug Inspection. CoNGAR, et al. "Lemons, Picking and Curing." Pacific Rural Press, Jan. 2, 1886. [Anon.] "Packing Citrus Fruits." Pacific Rural Press, Jan. 21, 1888, p. 43. [Anon.] "Rules for Grading California Oranges." Am. Pom. Soc. Proc. 1907, p. 109. Allison, L. R. W. "The Precooling Plant of the Santa Fe Rail- way." The Railway and Eng. News, May 11, 1912. Call, A. F. "Time to Pick Citrus Fruits." Calif. Cultivator, Feb. 19, 1914, p. 229. 490 Bihliography Temple, W. C. "Preparing Citrus Fruits for Market." Proc. 32d Session Am. Pom. Soc. 1911, pp. 77-83. Haizup, W. T. "Forms for Packing-House Bookkeeping." Florida Grower, Oct. 18, l'.)i:]. Newcomer, E. J. "Methods of Handling Citrus Fruits in Seville." Calif. Cultivator, Nov. 6, 1913. Newlin, J. A. "Tests of Packing Boxes of Various Forms." U. S. D. A. Forest Service, Cir. 214, 1913. HosFORD, G. W. "Cooperation in the Handling of Lemons in California." Cornell Countryman, Vol. 11, No. 7, 1913, p. 209. Hume, H. H. "Packing Citrus Fruits." Florida Exp. Sta. Bui. 63, 1902. Lelong, B. M. "Packing Oranges." Ilpt. Calif. State Bd. Hort. 1889, p. 141. 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"Preliminary Test of Cloth Covers for Reducing Radiation." Calif. Cultivator, May 9, 1912. BuTTERWiCK, O. C. "Root Pruning as Frost Protection." Florida Agriculturist, No. 18, p. 280, 1899. Onderdonk, G. "Dormant Orange Trees and Winter Injury." Texas State Dept. Agr. Bui. 18, 1911. Bibliography 495 WooDBRiDGE, T. R. "Orchard Heating Costs." Pacific Rural Press, May 24, 1913, p. 588. Whitney, D. J. "Frost and Northern Cahfornia Oranges." Pacific Rural Press, Nov. 29, 1913. [Anon.] "Electric Orchard Heaters." Pacific Fruit World, Vol. 37, No. 17, Dec. 1912. Mead, T. L. "A Frost Proof Orange Orchard." Country Life in America 7 (1905), No. 4, p. 367. Richardson Bros. "Cost and Result of Orchard Firing." Calif. Cultivator, Feb. 27, 1913, p. 260. Merrill, G. E. "The Freeze and Frost Fighting." Pacific Rural Press, Feb. 22, 1913. Whitney, D. J. "Overhead Irrigation and Frost." Pacific Rural Press, Jan. 25, 1913. McAdie, a. D. "Frost Fighting Methods, History and Progress." Pacific Rural Press, May 4, 1912. Webber, H. J. "Advice to Citrus Growers after 1913 Freeze." Pacific Fruit World, Feb. 1, 1913. Smith, F. J. "Cooperation in Frost Prevention." Calif. Culti- vator, May 9, 1912, p. 584. Call, A. F. "The Relation of Frost Protection to the Citrus Industry." Calif. Cultivator, May 9, 1912, p. 588. Lei FERTs, D. C. "Alcohol for Separation of Frosted Fruit." Calif. Cultivator, May 9, 1912, p. 583. Adamson, J. E. "EHmination of Frosted Fruit." Pacific Rural Press, May 10, 1913, p. 541. "Government Definition of Frozen Oranges." Pacific Rural Press, Feb. 1, 1913, also Decision No. 150, U. S. Board Food and Drug Inspection. Mann, C. W. "Keeping Quality of Citrus Fruit Treated to Elimi- nate Frosted Fruit." Calif. Cultivator, May 9, 1912, p. 582. BioLETTi, F. T. "Experiment to Determine the Condition of Cell Walls of Frozen Oranges." Calif. Exp. Sta. Rpt. 1897-98, p. 184. 496 B ibliog rap hy " Insect Pests GossARD, H. A. "The Cottony Cushion Scale." Florida Exp. Sta. Bui. 56, 1901. Kellom, J. H. "Resin Spray and Its Effects on Citrus Trees." Rpt. Calif. State Bd. Hort. 1889, p. 420. QuAYLE, H. J. "Citrus Fruit Insects." Calif. Exp. Sta. Bui. 214, 1911. "The Purple Scale." Calif. Exp. Sta. Bui. 226, 1912. "The Black Scale." Calif. Exp. Sta. Bui. 223, 1911. "The Red or Orange Scale." Calif. Exp. Sta. Bui. 222, 1911. "Red Spiders and Mites of Citrus Trees." Calif. Exp. Sta. Bui. 234, Nov. 1912. "Locomotion of Certain Young Scale Insects." Journ. Econ. Ent. June, 1911, p. 301. Wood WORTH, C. W. "The Red Spider of Citrus Trees." Calif. Exp. Sta. Bui. 145, 1902. GossARD, H. A. "The White Fly." Florida Exp. Sta. Bui. No. 67, 1903. WooDWORTH, C. W. "The White Fly in California." Calif. Exp. Sta. Circular 30, 1907. "White Fly Eradication." Calif. Exp. Sta. Circular 32, 1907. Carnes, E. K. "Practical Work in Combating' the Citrus White Fly." Proc. 23d Calif. Fruit Growers' Convention, 1907, p. 133. Berger, E. W. "White Fly Conditions in 1906; the Use of the Fungi." Florida Exp. Sta. Bui. 88, 1907. YoTHERS, W. W. "Spraying for White Flies in Florida." U. S. D. A. Bureau Ent. Circular 168, 1913. Berger, E. W. "White Fly Studies in 190S." Florida Exp. Sta. Bui. 97, 1909. "Investigations of the White Fly." Florida Exp. Sta. Rpt. 1908. Morrill, A. W. "The White Fly Enemies of Citrus." Arizona Hort. Com. Circular 13, Jan. 18, 1910. Day, C. A., Wood, Wm., et al. "Citrus Scales and Their Treat- 'Bibliography 497 ment." Proc. 23cl Calif. Fruit Growers' Convention, 1907, p. 163. Neuls, J. D. "The Use of Flour Paste in Lime-Sulfur Solutions in the Control of Citrus Red Spiders." Monthly Bui. Calif. State Com. Hort. June, 1913, p. 557. Vaile, R. S. "Citrus Mealy Bugs." Calif. Cultivator, Feb. 27, 1913. Marlatt, C. L. "Scale Insects and Mite Enemies of Citrus Trees." Scientific American Sup. Vol. 52, pp. 21494-7. Severin, H. p. "The Introduction, Methods of Control, Spread and Migration of the Mediterranean Fruit Fly in the Hawaiian Islands." Monthly Bui. Calif. State Hort. Com. Vol. 1, No. 9, p. 558, 1912. EssiG, E. 0. "Plant Lice Affecting Citrus Trees." Monthly Bui. Calif. State Hort. Com. Vol. 1, No. 7, 1912, p. 282. Fawcett, H. S., and Burger, O. F. "Spraying and the Citrus Purple Scale." Florida Exp. Sta. Press Bui. 183, Feb. 3, 1912. Marlatt, C. L. "Scale Insects and Mites of Citrus Trees." U. S. D. A. Farmers' Bui. 172, 1903. Tower, W. V. "Insects Injurious to Citrus Fruits and Methods for Combating Them." Porto Rico, Exp. Sta. Bui. 10, 1911. Severin, H. P. "Life History of the Mediterranean Fruit Fly in Hawaii." Journ. Econ. Ent. Vol. 6, Oct. 1913. Mills, J. W. "Poisoning Grasshoppers on Orange Trees." Calif. Cultivator, May U, 1914, p. 606. Fumigation Morse, F. W. "The Use of Gases Against Scale Insects." Calif. Exp. Sta. Bui. 71, June 12, 1887. "The Use of Hydrocyanic Acid Against Scale Insects." Calif. Exp. Sta. Bui. 73, Aug. 27, 1887. CoQUiLLETT, D. W. "Report on Gas Treatment for Scale Insects." U. S. D. A. Report 1887, pp. 123-142. Morse, F. W. "Experiments on the Cause and Avoidance of In- 498 Bibliography jury to Foliage in the Hydrocyanic Gas Treatment of Trees." Caiif. Exp. Sta. Bui. 79. May 5, ISSS. CoQUiLLETT, D. W. "Supplementary Report on the Gas Treat- ment for Scale Insects." Insect Life, Vol. 1, pp. 41-42. "Report on Various Methods for Destroying Scale Insects." U. S. D. A. Report 1888, pp. 123-133. "Hydrocyanic Acid Treatment for Scale Insects." Insect Life. Vol. 1, p. 286. "The Use of Hydrocyanic Gas for the Destruction of the Red Scale." Insect Life, Vol. II, pp. 202-207. Lelong, B. M. "Improved Fumigating Apparatus." Rpt. Calif. State Bd. Hort. 1890, pp. 469-472. Craw, Alex. "Gas Treatment for Destroying Scale Insects upon Citrus Trees." Rpt. Calif. State Bd. Hort. 1893-94, pp. 105-109. WooDWORTH, C. W. "Orchard Fumigation." Calif. Exp. Sta. Bui. 122, Jan. 1899. "Fumigation Dosage." Calif. Exp. Sta. Bui. 152, 1903. "Fumigation Scheduling." Calif. Exp. Sta. Circular 50, 1910. "Dosage Tables." Calif. Exp. Sta. Bui. 220, 1911. "A New Leakage Gauge." Calif. Exp. Sta. Circular 75, 1912. Morrill, A. W. "Fumigation for Citrus White Fly." U. S. D. A. Bureau of Ent. Bui. 76, 1908. Morrill, A. W. and Yothers, W. W. "Preparations for Winter Fumigation for the Citrus White Fly." U. S. D. A. Bureau of Ent. Circular 111, 1909. WoGLU.M, R. S. "Investigation of the Use of Hydrocyanic Acid Gas in Fumigating Citrus Trees." Proc. 34th Calif. State Fruit Growers' Convention, May 1, 1908, p. 103. "Fumigation of Citrus Trees." U. S. D. A. Bureau of Ent. Bui. 90, part 1, 1911. "The \'alue of Sodiiun Cyanide for Fumigation Purposes." U. S. D. A. Bureau of Ent. Bui. 90, part 2, 1911. "An Improved Fumigation Generator." Calif. Cultivator, Aug. 7, 1913, p. 126. Bibliography 499 "The Fumigation of Citrus Trees." Calif. Cultivator, Sept. 11, 1913. McDonnell, C. C. "Chemistry of Fumigation with Hydrocyanic Acid Gas." U. S. D. A. Bureau of Ent. Bui. 90, part 3, 1911. ScHOENE, W. J. "The Influence of Temperature and Moisture on Fumigation." New York (Geneva) Exp. wSta. Tech. Bui. 30, 1913. Bache, R. "Fumigation of Citrus Fruit Orchards." Technical World, Vol. 16, p. 209, Oct. 1911. Diseases Smith, R. E., and Smith, E. H. "Citrus Diseases." In Calif. Expt. wSta. Bui. 218, June, 1911. Swingle, W. T., and Webber, H. J. "Diseases of Citrus Fruits in Florida." U. S. D. A. Vegetable Phys. and Path. Bui. 8, 1896. Hume, H. H. "Some Citrus Troubles." Florida Exp. Sta. Bui. 53, 1900. McAlpine, D. "Fungus Diseases of Citrus Trees in Australia." Melbourne, Nov. 1899. Fawcett, H. S. "Citrus Diseases." Fla. Exp. Sta. Rpt. 1908. "Scaly Bark of Citrus." Fla. Exp. Sta. Bui. 98, 1909. "Citrus Scab." Fla. Exp. Sta. Rpt. 1909. "Bucksin of Citrus Fruits." Fla. Exp. Sta. Rpt. 1909. "Relation of Wither-tip to Scaly-Bark." Fla. Exp. Sta. Rpt. 1909. "Webber's 'Brown Fungus' of the Citrus Whitefly." Science, N. S. Vol. 31, No. 806, p. 912, 1910. "Silver Scurf of the Orange." Fla. Exp. Sta. Rpt. 1910. "Citrus Scab or Verrucosis." Fla. Exp. Sta. Rpt. 1910. "Stem End Rot of Oranges and Pomelos." Fla. Exj). Sta. Rpt. 1910. "Scaly Bark or Nail Head Rust." Fla. E.xp. Sta. Rpt. 1910. 500 B ih I log ra p h y Fawcett, H. S. "Scaly Bark or Nail Head Rust of Citrus." Florida Exp. Sta. Bui. 106, 1911. "Stem End Rot and Gummosis." Fla. State Hort. Soc. Proc. 1911, p. 41. "Stem End Rot of Citrus Fruits." Fla. Exp. Sta. Bui. 107, 1911. and Burger, O. F. "A Gum Inducing Diplodia of Peach and Orange." Mycologia, Vol. Ill, No. 3, May, 1911. "A Variety of Cladosporium Herbarum on Citrus Aurantium in Florida." Phytopathology, Vol. 1, No. 5, 1911. "The Cause of Stem End Rot of Citrus Fruits." Phytopathology, Vol. 2, No. 3, June, 1912. "Citrus Gumming in Florida." Fla. Exp. Sta. Rpt. 1912. "Citrus Galls." Monthly Bui. Calif. State Com. Hort. Vol. 1, No. 13, Dec. 1912, p. 937. "Citrus Scab." Monthly Bui. Calif. State Com. Hort. Vol. 1, No. 11, Oct. 1912, p. 833. "Two Fungi as Causal Agents in Gummosis of Lemon Trees in California." Monthly Bui. Calif. State Hort. Com. Vol. 2, No. 8, Aug. 1913. Smith, R. E. "Mottled-Leaf of Citrus Trees." Calif. Cultivator, May 25, 1911. Thomas, E. E. "A PreUminary Report of a Nematode Observed on Citrus Roots and Its Possible Relation with the Mottled Appearance of Citrus Trees." Calif. Exp. Sta. Circular 85, Feb. 1913. Vaile, R. S. "Citrus Nematode." Annual Rpt. Ventura County Hort. Com. 1913. Cobb, N. A. "Citrus Root Nematode." Jour. Agr. Research, Vol. II, No. 3, June, 1914. Thomas, E. E. "The Nematode Worm on the Roots of Citrus Trees." Calif. Cultivator, July 9, 1914, p. 28. Kellerman, K. F., and Wright, R. C. "Relation of Bacterial Transformations of Soil Nitrogen to Nutrition of Citrus Plants." Journ. Agr. Research, Vol. 2, No. 2, May, 1914. Bibliography 501 GiLE, P. L. "Relation of Calcareous Soils to Pineapple Chlorosis." Porto Rico Exp. Sta. Bui. 11, 1911. Floyd, B. F. "Frenching, Yellow Spotting, Die-Back, and Melanose of Citrus." Fla. Exp. Sta. Rpt. 1910. "Yellow Spotting of Citrus Groves." Fla. Exp. Sta. Rpt. 1909. HiLGARD, E. W. "Marley Subsoils and the Chlorosis or Yellowing of Citrus Trees." Calif. Exp. Sta. Circular 27, 1906. CoiT, J. E. "Mottled-Leaf of Citrus not vSpread by Budding." Calif. Cultivator, Jan. 18, 1912, p. 68. Snowtden, R. R. "Magnesia-Lime Chlorosis of Citrus Trees." Calif. Cultivator, Aug. 11, 1910. LiPMAN, C. B. "Chlorosis of Citrus Trees and the Physical Condi- tion of the Soil." Calif. Cultivator, June 1, 1911. "Poor Nitrifying Power of Soils a Possible Cause of Mottled- Leaf and Die-Back of Lemons." Science, N. S. Vol. 39, No. 1011, pp. 728-730, May 15, 1914. CoiT, J. E. "E.xanthema or Die-Back of Citrus Trees." Calif. Cultivator, March, 12, 1914. EssiG, O. E. "Exanthema or Die-Back of Citrus Trees." Pomona College Journal of Econ. Bot. Vol. 1, No. 2, May, 1911. Brittlebank, C. C. "Exanthema of Orange Trees in Australia." Journ. Agr. Victoria, July, 1912, p. 401. Tenny, L. S. and Hosford, G. W. "The Decay of Florida Oranges while in Transit and on the Market." U. S. D. A. Plant In- dustry Circular 19, 1908. Stevens, H. E. "Melanose and Stem End Rot." Florida Grower, Nov. 1, 1913. " Citrus Melanose." Fla. Exp. Sta. Rpt. 1912. Floyd, B. F. "Experiments with Citrus Die-Back." Fla. Exp. Sta. Rpt. 1912. "Melanose of Citrus." Fla. Exp. Sta. Rpt. 1911. Cobb, N. A. "Alternarias of Citrus." Dept. Agr. New South Wales, Misc. Pub. 666, 1904. 502 Biblwgraphii Floyd, B. F., and Stevens, H. E. "Melanose and Stem End Hot." Florida Exp. Sta. Bui. Ill, 1912. Savastano, L. "Leforne teratoligiche del fiore e frutto degli Agruini." Agricoltura Portici, Vol. IV, 18S4. Grossenbacher, J. G. "Experiments on the Decay of Florida Oranges." U. S. D. A. Plant Ind. Circular 124, 1913. Hedges, F., and Tenney, L. S. "A Knot of Citrus Trees Caused by Sphaeropsis tumefaciens." U. S. D. A. Bureau Plant Ind. Bui. 247, 1912. Stevens, H. E. "Citrus Canker." Fla. Exp. Sta. Bui. 122, March, 1914. Rolfs, Fawcett, and Floy'd. "Diseases of Citrus Fruits." Florida Exp. Sta. Bui. 108, 1911. Clausen, R. E. "A New Fungus Concerned with Wither-tip of Varieties of Citrus Medica." Phytopathology, Vol. 2, No. 6, Dec. 1912. Rolfs, P. H. "Wither-tip and other Diseases of Citrus Trees and Fruits." U. S. D. A. Plant Ind. Bui. 52, 1904. Cook, M. T., and Horne, W. T. "Wither-tip." Cuba (Santiago de Los Vegas) Bui. 9, 1908. Smith, R. E. "Wither-tip." Calif. Cultivator, July 27, 1911. EssiG, E. O. "Wither-tip and Its Treatment." Calif. Cultivator, May 25, 1911. "Wither-tip of Citrus Trees." Pom. Col. Journ. Econ. Bot. Feb. 1911. Rolfs, P. H. "Fall Dropping of Citrus Fruits." Fla. Exp. Sta. Press, Bui. 60, Oct. 15, 1906. "Citrus Bloom Dropping." Fla. Exp. Sta. Press, Bui. 84, March 9, 1908. Floyd, B. F. "Experiments on Die-liack of Citrus." Fla. Exp. Sta. Rpt. 1909. Home, W. T. "Root Rot of Citrus Trees." Proc. 37th Calif. Fruit Growers' Convention, 1910, p. 93. Rolfs, P. H., and Fawcett, H. S. " Fungus Diseases of Scale Bibliography 503 Insects and White Fly." Florida Exp. Sta. Bui. 94, 1908. CoiT, J. E. "Blemishes of Citrus Fruits." Proc. :39th Calif. State Fruit Growers' Convention, 1911, p. 22. Butler, O. " A Study on Gummosis of Citrus and Prunus, with Observations on Squamosis and Exanthema of Citrus." Annals of Botany, Vol. 25, No. 97, Jan. 1911, p. 107. Cook, M. T. "Diseases of Citrus Fruits." In "Diseases of Tropical Plants," pp. 116-30, 19i:i. INDEX PPOPERTT imAST N. C. State College Abrasions, how caused, 278. Absentee ownership, 356. Acid, .contained in fruit, 63 ; sul- furic for fumigation, 439 ; loss of in respiration, 287. Acreage, citrus, in California by counties, 22 ; in California in- creasing, 354. Advertising, division of Exchange, 350, 351. Agents, bonded salesmen of Ex- change, 348. Air, importance of in soil, 165. Alfalfa, as interculture crop, 159 ; as a mulch, 173 ; as cover-crop, 182. Alignment, of fruit in box, 138. Alternaria, affecting stored lemons, 382. Alternaria citri, causing fruit decay, 388. Ammonia compounds, prejudicial to citrus trees, 372 ; as a cause of mottled-leaf, 379. Analyses of soils, 175. Antiquity of citrus fruits, use in Hebrew ceremonies, 40. Aphids, 427. Aphis gossypii, 427. Aramigus fuUeri, 429. Arizona, citrus production in, 23. Armillaria mellea, 145, 373. Artesian wells, for irrigating, 192. Artificial coloring, by sweating, 284 ; federal legislation regard- ing. 285. Asher, J. M., 20. Asphaltum, paint for wounds, 227 ; in fuel oil, 260 ; for wash tanks, 386. Aspidiotus hederae, 420. Aspidiotus rapax, 420. Assessments, for expenses of Ex- change, 348. Associations, 345 ; affiliated with Exchange, 301 ; first organized, 8; organization of, 351. Atmometer, records at Whittier and Riverside, 189. Atmospheric humidity, effect on citrus trees and fruit, 34. Aurantium, derivation of word, 41. Australia, frost in, 25 ; introduc- tion of Navel orange, 15 ; ship- ping oranges to, 344 ; source of cottony cushion scale, 6. Australian Navel orange, introduc- tion of, 16. Australian type, 128. Automatic weighing, of individual grades, 292. Automobile, used in killing gophers, 458. Azores, 15, 70. Backus, W. H., 58. Bacteria, in soil, 165. Bacterium citriputcale, 401. Bags, for picking, 280. Bahia, Brazil, birthplace of Navel orange, 13. Balling, nursery stock, 104. 505 506 Index Bare rooted, trees for planting, 157. Bark, effect of Botrytis vulgaris on, 366 ; gnawed by squirrels, 458 ; new growth of, chlorophyll in, 49 ; of sour orange resistant to gum-disease, 366. Barnyard manure, cost of, 361. Barometer, indicating frost, 237. Baronio system of pruning, 214. Bench-roots, 89. Bergamot oil, imported, 332 ; tariff on, 9. Beveling machines, 293. Bibliography, general, 461. Bigelow, W. D., 288. Bioletti, F. T., quoted, 240. Bisulfide of carbon, for killing gophers, 457. Biting insects, 405. Bitter orange, origin of, introduc- tion into Florida, 41. Black leaf extract, as a spray for thrips, 427. Black pit of lemon, 401. Black rot of Navel, 388. Black scale, general discussion of, 405. Black smut, 290. Blasting, to facilitate irrigation, 203, hard soil, 156; to ame- liorate soil, 146. Blemishes, importance in judging, 134; of fruit, 318. Blizzards, 237. Blue mold, 387. Bluestone, as a disinfectant, 385. Bolting split limbs, 229. Bolton, J. P., 252. Bonavia, E., 60. Boosting plants, 193. Bordeaux mixture, for seed-bed gumming, 89, 369 ; for wither- tip, 381 ; for damp-off, 392. Bordeaux paste, for gum-disease, 366 ; for pruning wounds, 228. Botany of citrus, bibliography, 485. Botrytis vulgaris, causing gum- disease, 366 ; causing fruit decay, 388. Box, dimensions of lemon box, 310 ; material, kind of, 293 ; cost of, 293 ; shooks, 292. Boxes, machines for making, 293 ; materials for, 292 ; size, 293. Breeding, references to literature, 479 ; for frost resistance, 244. Brehm, 14. Brokerage charges, compared with Exchange costs, 351. Brown rot fruit decay, 386. Brown rot fungus, transmission by rain, 281 ; regions most seriously affected, 282. Brown rot gum-disease, 364. Brown spot, of Navel orange, 326 ; description of, 389. Bruises, 321. Brushing, removal of dust by dry brushing, with water, 291. Buckwheat, as cover-crop, 182. Budding, time of, 95 ; nursery stock, 92; method of, 95; high bud- ding on sour-stock, 97 ; dormant buds, 98 ; cost, 99. Bud-sports, 120; how pruned, 211. Bud variation, 118. Bud-wood, selection of, 93, 128. Burr clover, as cover-crop, 182. By-product industry, needed in California, 354. By-products, references to litera- ture, 492 ; importation of, 331. California Fruit Growers' Exchange, history and organization of, 345. California Navel Orange, chemical analysis of, 62. California pruning saw, 225. Canada field peas, as cover-crop, 182. Canker, description of, 392. Capital, estimating amount needed, 360 ; of Exchange, 348. Index 507 Capital required, 358. Capitalization, 356. Carbon bisulfide, for killing gophers, 457. Carbon dioxide, loss of from fruit, 61. Car-load, number of boxes con- tained, 310. Cars, standard, 295; other than standard, 275 ; air spaces in, 296 ; bracing of boxes in, 296 ; freisht on, 297; icing charges, 297. "Car Squeeze," 296. Cement dust, on fruit, 324. Central exchange, 348. Ceratitis capitata, 109. Chambers of Commerce, influence of, 11. Chapman, A. B., 16. Chapman, C. C, 71. Characters, segregation of, 120. Chemical Analyses of California Oranges and Lemons, 62. Chemical fertilizer, cost of, 361. Chemistry, references to literature, 486. Chemistry of citrus fruits, 61. Chenopodium, as a cover-crop, 183. Chimeras, 120. Chinese lemon, as a root-stock, 154. Choice, grade, 292. Chrysomphahis aurantii, 411; var. citrinus, 414. Citellus beecheyi, 458. Citranges, 79. Citrate of lime, imported, 332; tariff on, 9. Citric acid, imported, 332 ; manu- facture of, 333 ; tariff on, 9. Citricola scale, discussion of, 419. Citron, preparation of, 337 ; bibliog- raphy, 473 ; grown in California, susceptibility to frost, variety Cor- sica, 80 ; imported, 332 ; introduc- tion into Italy, 41 ; susceptibility to frost, 242 ; tariff on, 9. Citrus areas of California, southern coast, interior valleys, northern coast, 26. Citrus aurantifolia, 43, 45. Citrus aurantium, 43. Citrus bergamia, 43. Citrus bibliography, 473. Citrus canker, description of, 392. Citrus decumana, 43, 44. Citrus japonica, 43, 44. Citrus Imionia, 43, 45. Citrus mealy bug, 421. Citrus medica, 43, 45. Citrus nobilis, 43. Citrus Protective League, 353. Citrus sinensis, 43. Citrus species in North and South America, 42. Citrus trifoliata, 43. Cladosporium citri, 395 ; herbarum var. citricolum, 395. Classification, 42. Clausen, R. E., cited, 381. Clearing land, cost of, 359. Cleats, proper position of, 138. Climate, interior valleys, 30 ; north- ern coast, 31 ; southern coast division, 28. Clipper cuts, 321. Clippers, abrasions caused by, 278. Clouds, as affecting frost, 235. Cobb, N. A., cited, 449. Coccus hesperidum, 418. Colby, G. E., 288. Cold periods, historical, 230. College of Agriculture, service of, 358. Colletotrichum gloeosporioides, 380. Collins, J. F., cited, 228. Color, importance in judging, 136. Coloring process, results of too rapid forcing, 290. Combustion, in orchard heaters, 253. Conmiission men, 344. Concrete irrigating pipe, 194. 508 Index Conduction, 233. Consumption, increase of, 354. Contour, planting, 150. Convection, 233. Cooperation, first tried, 8 ; in frost fighting, 274. Cooperative packing-houses, 345. Copley, Edward, 252. Coquillett, D. W., 431. Core rot, of stored lemons, 382. Correspondence course, in citrus fruits, 358, 11. Cost of production, 355. Costs, of bringing orchard into bear- ing, 359. Cotton Exposition, held in New Orleans, 6. Cottony cushion scale, discussion of, 417 ; fumigation for, 431 ; in- troduced, 6. Cottony mold, 383. Cottony-mold fungus, on vetch cover-crop, 182. County Commissioners of Horti- culture, 110. Cover-crop, advantages of, 181 ; disadvantages of, 182 ; kinds, 182 ; references to literature, 484 ; harbors cottony mold, 383 ; plowed under, 166 ; relation to mottled-leaf, 379. Cover, T. D., first exhibited Navel orange, 18. Cowpeas, as cover-crop, 182. Cracks, in oranges, 326. Craw, Alexander, 20. Creosote, 227. Cross-furrowing, for irrigation, 201. Cross-pollination, 123, 115, 116. Crown gall, occurs on citrus, 401. Cucumber beetle, 430. Culls, removal of, 315. Cultivation, 165 ; depth of, fre- quency of, 168. Cultivator scars, on fruit, 321. Curing, advantages of, 278 ; refer- ences to literature, 489. Cuttings, propagation by, 92. Cyanide, 438. Damp-off fungus, in seed-bed, 88. Damping off, of seed-bed stock, 391. De Candolle, 40. Decay, in pruning wounds, 226 ; in transit, effect of icing on, 297 ; in oranges, causes of, 277 ; in dropped fruit, 279 ; in stored lemons, 308 ; splits a cause of, 327. Defoliation, by frost, 242. Degenerate types of trees, 357. Degeneration of trees, due to suckers, 209. Demonstration trains, influence of, 11. Desiccating winds, cause of twig gumming, 367. Dew, as affecting frosts, 235. Dew point, raising of, 246. Diabrotica soror, 430. Die-back, see exanthema, 369. Digging holes, for trees, 155. Dimorphic branches, of orange trees, 208. Diplodia rot, due to Diplodia natalensis, 397. Discount, in cars other than stand- ard, 295. Diseases, prevention important, 357 ; bibliography, 499 ; control, 364. Disinfection, of wash water, 385. Distance apart, of trees, 149. Distillate oil, as a spray for scale, 432. Distributing costs, 352. Distribution, of fruit by Exchange, 348. District exchange, 347. Diversion of cars, right of, 298. Domestic recipes, 341. Index 509 Dosage for fumigation, calculating, 441,444; schedules, 444-447. Double clipping, 279. Dressings for wounds, 227. Dropped fruit, decay of, 279. Dry center, of lemons, 329. Drying, of fruit, 291. Dynamite, 146. Early ripening, of oranges in Northern California, 288. Early shipments, losses in, 283. Electric orchard heaters, 250. Electric railways, influence of, 10. Elevation, effect of in Interior VaUey, 30. Elm, affected by mottled-leaf, 376. Employees, provision for, 316. Englehardt, J. P., 69. Enzymatic fermentation, of fruit, 61. Eriophyes oleivorus, 424. Erodium, as cover-crop, 183. Essence of orange flowers, 338. Essential oils, manufacture of, 334. Etrog, 40. Eucalyptus, affected by mottled- leaf, 376. Eureka lemon, pollination of, 55 ; chemical analysis of, 62 ; how pruned, 214. Euthrips citri, 425. Evaporation, as affecting tempera- ture, 233 ; from porous cup atmometers, 189 ; from soil, 165. Ever-sporting trees, 211. Exanthema, causing blemishes on fruit, 325 ; description of, 369. Exchange, relation to other selling agencies, 345 ; cost of operating, 351 ; Southern California Fruit Exchange first organized, 8. Exhibitions, judging fruit at, 132 ; influence of, 12. Explosions, in orchard heaters, 255. Fairs, first citrus fairs, 5. Fancy, grade, 292. Fawcett, H. S., cited, 397. Feature exhibits, judging, 138. Federal Board of Food and Drugs Inspection, ruling regarding col- oring of green citrus fruits, 285 ; effect of ruling regarding artificial coloring, 285. Fenugreek, as cover-crop, 182. Ferrarius, John Baptiste, 13. Fertilization, of seed-bed, 88; bib- liography, 483 ; of nursery stock, 92; of orchards, 175; a type of, 178. Fertilizer, in planting holes, 157 ; cost of, 359. Field box, ratio of to packed box, 295. Filaree, as cover-crop, 182. Fingered lemons, 120. Flavor, importance in judging, 136. Florida Citrus Exchange, organiza- tion of, 353. Flowers of citrus, description, season, 52 ; of lemon, different kinds of, 54. Fluctuations, 118, 128. Foot-rot, 372. Form, importance in judging, 133. Fortunella, 43. Freezing in transit, prevention of, 298. Freight, cost of, 360. Freight rate, on lemons, 312. Freight rates, 297. Friendly fungi, 396. Frost, effect on fruit on lower branches, 281 ; in countries pro- ducing citrus fruits, 25; hazard, 33 ; air currents, 34 ; effect on value of land, 140; where to be expected, 140; of January, 1913, 231 ; losses from, 232; factors influencing, 234 ; local conditions affecting, 236 ; relative resist- 510 Index ance to, 242 ; causing bleiiiishes on fruit, 325 ; a frequent cause of failure, 357. Frost fighting, bibliography, 494. Frost hazard, judgment of, 141. Frost-injured fruit, references to literature, 494. Frost injury, to vegetable tissues, 239 ; on leaves, 368 ; prevention of, 243. Frost protection, average cost of, 361. Frosted fruit, separation of, 270. Frosted trees, how pruned, 217. Frosts, as affected by winds, 233 ; in Florida, 230 ; in California, 231 ; season of in California, 232 ; forecasting, 233. Froude, Charles, 252. Frozen fruit, changes in, 241 ; edible, 241 ; loss of juice, 241. Fruit Growers' Supply Co., organi- zation, 301 ; purpose, 301 ; ac- complishments, 301. Fuel oils, properties of, 260 ; stor- age of, 262. Fuller's rose beetle, 429. Fumigating, machine, 452 ; cost of materials, 452 ; cost of, 361 ; done by associations, 347 ; large seedlings difficult to cover with tents, 65. Fumigation, 431 ; season of, 443 ; operation, 440 ; cost of, 448 ; efficiency of, 403 ; bibliography, 497 ; scars, 322. Fumigator's supply carts, 438. Furrows, for irrigation, 201. Fusarium, causing damp-off, 391. Galloway, B. T., quoted, 239. Galls, on citrus trees, 401. Garey, T. A., 4, 71, 74; introduc- tion of varieties, 16. Generators, fumigation, 437. Geomys bursarius, 456. Germ-plasm, 211. Glaced kumquats, 341. Gloeosporium limetticolum, 381. Gopher, 456. Gore, H. C, 288. Grades, of fruit, 292. Grading, fruit, 292 ; land, cost of, 359. Grafting, nursery stock, 92. Grape fruit, see pomelo, 75. Gravity frost, 237. Gray mold, of fruit, 388. Gray scale, 419. Greedy scale, 420. Green manure crops, 181. Green manuring, references to litera- ture, 484. Green mold, 387. Ground squirrels, 458. Growth rings, in wood of lemon, 47. Guaymas, citrus industry at, 24. Gum-disease, of seed-bed stock, 89, 368 ; in pruning wounds, 229 ; caused by tillage implements, 172 ; carried by shoes of pickers, 280. Gum-diseases, 364. Gum, formation along cambium, 49. Gumming, resistance of sour stock to, 152. Hail scars, 323. Hairy vetch, as cover-crop, 182. Hammon, W. H., cited, 235. Hardpan, 143 ; presence of, in In- terior Valley, 31 ; as affecting irrigation, 203. Harrowing, 168. Hart, E. H., 71. Harvest season, of oranges, of lemons, 63. Hauling fruit, average cost of, 360. Heading back, nursery trees, 100. Heading trees, 205. Heat, loss of, 233. Index 511 Hedges, Florence, cited, 401. Hemispherical scale, 420. Hermosillo, citrus planting at, 24. Hesperides, The, 13. Hesperidin, 241. Hexagonal planting, 14 of, 156. Planting plans, 147. Planting seed, 87. Plant lice, 427. Plowing, 165 ; depth of, 166 ; time of, 166. Plows, kinds of, 166, 170. Plow-sole, 166 ; as affecting irriga- tion, 203. Pocket gopher, 456. Poison, for gophers, 457 ; for ground squirrels, 459. Poiteau, 40. Pollination, 123 ; in citrus fruits of Florida, 55; in citrus fruits of Southwest, 45. Polyembryony, in hybrids, in citrus seeds, causes of, sig- nificance of, 59. Pomelo, subject to canker, 392 ; susceptibility to frost, 242 ; as a rootstock, 152 ; improvement by hybridization, 118; bibliography, 472 ; picking, 312 ; tariff on, 9 ; standards for judging, 136. Pomelos, varieties, description of Marsh, 75 ; Nectar, 77 ; Duarte Seedling, 77 ; Duncan, 77 ; Triumph, 77 ; Imperial, 77 ; Colton, 77 ; Pixik-fleshed, 77. Potash, as a crop limiter, 177. Potassium cyanide, for fumigation, 449. Powell, G. H., quoted, 353, 346. Precooling, value to citrus fruits, 298 ; definition of, 297 ; com- parison with icing, 297 ; amounts of ice required, 298. Precooling plants, 297. Prickly ash, 42. Privet, Japanese, affected by mottled-leaf, 376. Production, 114, 25; in California, 9. Profit and loss, 355. Propagation, 92 ; references to literature, 478. Propping trees, cost of, 361. Protective duties, tariff, 9. Protective League, 353. Pruning, as a prevention of brown- rot, 387 ; orange trees, 207 ; cost of, 359 ; done by associations, 347 ; frosted trees, 217 ; time of, 216; maxims of, 215; lemons, 213 ; training nursery trees, 205 ; general considerations, objects of, 204 ; bibliography, 487. Prunings, disposition of, 217. Pruning tools, 225. Pruning wounds, 226. Pseudococcus citri, 421. Puddling roots, 155. Puffing, 329. Punctures, caused by stems, 278 ; box-nails, 279 ; thorns, 279. Purple scale, 414. Pythiacystis citrophthora, 365 ; causing fruit decay, 386. Quality, in tropical grown citrus fruits, 25. Quarantine, horticultural, 6. Quincunx planting, 148. Radiation, 234 ; checking of, 244 ; of electric orchard heaters, 251. Rag, importance in judging, 134. Railroads, early shipments by rail, 5. 516 Index Rainfall, 26 ; as affecting irrigation, 188. Recipes, 341. Red blotch of lemon, described, 398. Red rot, see red blotch. Red scale, discussion of, 411 ; dis- tribution of, 404. Red spiders, discussion of, 423. Reed, J. H., 23. Refrigeration, cost of, 360. Reheading, mature trees, 220 ; young trees, 218. Re-icing, cost of, rate case con- cerning, 298. Relative humidity of air, as affect- ing irrigation, 188. Relative size in fumigation dosage, 451. Respiration, of oranges, 277. Reversion, 120. Rhizoctonia, 391. Right of diversion, 298. Rind, importance in judging, 133 ; variation in thickness of, 328. Ringing, 48. Rings of growth, 47. Ripening season. Northern Valley, 31. Risso, 40. Rivers, Thomas, 70, 15. River's Navel orange, 16. Riverside, first settled, 3 ; citrus fairs, 19, 5. Riverside Press and Horticulturist, quoted, 19. Roosevelt, President, 22. Root-rot, due to sclerotinia, 383 ; due to toadstools, 373. Roots, distribution in soil, effect of shearing, 45 ; effect of hardpan on, 143 ; injured by exposure to air, 91 ; cut by plow, 156 ; of lemon, susceptible to foot-rot, 372 ; affected by nematodes, 454. Root-stock, 151 ; trifoliata suitable for kumquats, 83 ; trifoliata best for Unshiu, 79 ; cold resisting, 155 ; proportion of different kinds planted, 84; Chinese lemon, 6. Root systems, references to litera- ture, 481. Rose beetle, 429. RutaceiE, 42. Saissetia hemisphEerica, 420. Saissetia olese, 405. Sales, classification of, 344 ; divi- sion of E.xchange, 350. Salesmen, of Exchange, 348. Salt River Valley, 23. San Gabriel Mission, site of first orchard, 2. Santa Fe Railway, 5. Sap Currents, nature of, 47 ; rela- tion to tree parts, 47. Satsuma orange, production of seeds in, 56 ; susceptibility to frost, 242. Saunders, William, 17. Savastano, 121. Saws, for pruning, 225. Scab, description of, 395. Scale insects, effect of climate on, 404 ; exclusion of, 357 ; ridding seed-bed stock of, 90; red, 411 ; yellow, 414; black, 405 ; purple, 414; brown, 418; gray, 410; cottony cushion, 417 ; greedj', 420 ; citricola, 419 ; hemispheri- cal, 420 ; oleander, 420. Scales, for judging, 132. Scaly-bark, 367 ; Florida t>ije, 395. Scars, on fruit, 321. Schedules, fumigation dosage, 444- 447. Schizophyllum commune, 399. Scientific American, 48. Scions, references to literature, 478. Sclerotinia libertiniana, causing fruit decay, 382. Score-card, for citrus land, 139; for bearing groves, 363 ; for Index 517 oranges, 133 ; for lemons, 134 ; for pomelos, 136 ; for packed boxes, 137 ; for feature exhibits, 138. Scratches, caused by shoes of pickers, 280 ; caused by finger- naUs, 279 ; gravel, 279 ; thorns, 279. Scutellista cyanea, 409. Season, of picking, 63. Seed-bed, planting, 84. Seed-bed stock, price, method of pulling, 88 ; trimming back when transplanting, 92. Seed, citrus, description of different kinds, 84; cost, 84; method of keeping, 86 ; number per bushel, 86. Seedlessness, importance of in pomelos, 77. Seedling trees, compared with budded trees, 65 ; 84. Seeds, presence of, in judging, 134, 136 ; time of planting, 88 ; effect of freezing on germination, 86 ; first planted in (California, 1. Seeds of citrus fruits, number of, 61. Selected buds, importance of, 357. Selection of bud-wood, effect of poor bud-wood, 1 14. Selling, average cost of, 360. Separators, for frosted fruit, 272. Setting of fruit, as affected by plow- ing, 166. Seville orange, susceptibility to frost, 242. Shaddock, description of, 81. Shading, of nursery plants, 38. Shamel, A. D., 124. Shears, for pruning, 225. Shields, for tillage implements, 170. Shipments, annual, in carloads, 9. Shipping, lemons, 312 ; first car shipped east, 3 ; nursery stock, 103. Shorb, J. de Barth, 18. Shoulder spots, 323. Silver mite, discussion of, 424. Silverware, as premiums, 351. Site, for planting, 139. Six-spotted mite, 423. Size, importance in judging, 135. Sizing, lemons, 310; machines, 292. Slitting bark, of young trees, 206. Slope, of land for irrigation, 201 ; best for planting, 150. Smith, C. O., cited, 401. Smith, R. E., quoted, 378. Smoke, from orchard heaters, 253. Smudge fuel, 250. Snowden, R. R., cited, 377. Sodium cyanide, for fumigation, 449. Sodium sulfate, a waste product of fumigation, 439. Soft brown scale, discussion of, 418. Soil, nitrification and ammonifica- tion, 379 ; heavy soil may en- courage gum-disease, 365 ; most desirable, 357 ; samples, 196 inoculation, 183; tillage of, 165 alkali, 144 ; ideal for citrus, 144 for seed-bed, 87. Soil acidity, 144. Soil adaptations, 142. Soil analysis, 144. Soils, relation to mottled-leaf, 378 ; kinds as affecting method of irri- gation, 200 ; kinds not benefited by cover-crop, 183 ; humus con- tent, 179 ; analyses of, 175 ; cul- tivation and management, 170 ; for seed-bed stock, 91 ; northern coast division, 32 ; Interior Valley division, 31 ; Southern Coast division, 29 ; references to literature, 481. Soil scars, on fruit, 323. Soil types, 142. Solauum nigrum, 404. 518 Index Sonora, citrus production in, 23. Sour clover, as cover-crop, 182. Sour-stock, as a root, 152. South Africa, 14 ; frost in, 25. Southern Pacific Railway, 5. Spain, frost in, 25. Special equipment, for packing- houses, 299. Speculation, encouraged by over- capitalization, 356. Speculators, 344. Sphceropsis tumefaciens, 401. Sphagnum, for packing bud-wood, 94 ; for packing seed-bed stock, 90. Splits, as blemishes, 326. Splitting of bark, effect of frost on, 219. Spores, of fungi in wash water, 385. Spotting, of Navel oranges in tran- sit, 389. Spraying, cost of, 361. Spraying under trees, as prevention for brown-rot, 387. Square planting, 148. Squirrels, as pests, 458. Staking young trees, in orchard, 218. Standard car, number of boxes in, 295; arrangement of boxes in, 295 ; air spaces in, 296. Standard grade, 292. Standpipes, for irrigation, 194. State Commission of Horticulture, influence on industry, 11 ; descrip- tion of, 106. State Fruit Growers' Convention, 109. Statute inch, 192. Stem, importance in judging, 133. Stem end rot, 394. Stem end spot, in California, 399 ; of oranges, 320. Stem punctures, 321, 278. Stenciling, of boxes, 293 ; impor- tance in judging, 137. Stevens, H. E., cited, 392. Stock, see Root-stock, 152. Stocks, references to literature, 478. Storage, 306. Storing, references to literature, 489. Strap, proper position of, 138. Straw, plowed under, a cause of mottled-leaf, 379. Structure of the fruit, morphologi- cal, 60. Strychnine, as poison for gophers, 457. Subsoiling, 166. Subsoils, 143. Sucker growths, 208. Sucker-nests, 226. Suckers, effect of presence of, 209 ; not desirable for bud-wood, 95. Sucking insects, 405. Sugar, reduction of, during respira- tion, 287. Sugars, in citrus fruit, 63. Sulfur, remedy for red spider, 424. Sulfuric acid, for fumigation, 439. Sunburn, of bark, encourages schizo- phyllum, 400. Sunburn, of leaves, 368 ; of fruit, 324. Sunburning, bark of pruned trees, 219. "Sunkist" label, 292, 351. Sunlight, effect of over-illumina- tion, 38 ; as affecting irrigation, 188. Sun protectors, 157. Supply cart, for fumigators, 438. Supply Department, of Exchange, 350. Sweating, lemons, 305 ; oranges, 282; of Valencia oranges, 282; references to literature, 489. Sweat room, description of, 289, 305 ; construction of, 289 ; tem- perature of, 290 ; heating of, 290 ; arrangement of fruit in, 290, Index 519 Sweet orange, antiquity, introduc- tion into Europe, introduction into Brazil, 41. Swingle, W. T., 79. Swingle-Webber hybrids, varieties, Rusk, 79; Willits, 79; Norton, 79; Colman, 79; Savage, 79; Rustic, 79 ; Thornton, 80 ; Samp- son, 80 ; Weshart, 80 ; Trimble, 80. Taber, G. L., cited, 155. Tait, C. E., quoted, 170. Tangelo, 79. Tangerines, picking, 312. Tanking newly planted trees, 158. Tannin, treatment for fumigating tents, 435. Tar, for pruning wounds, 228. Tariff, references to literature, 490 ; protective duties, 9. Taxes, 357 ; and incidentals, cost of, 359. Teague, R. M., 77, 69. Temperature, effect on fumigation, 448 ; of air, as affecting irriga- tion, 188. Tent fumigation, of citrus trees, 435. Tents, for storing lemons, 308 ; cost of, 452 ; acid holes in, 438 ; equipment of, 437 ; methods of marking, 436 ; fumigation, 435. Teratological forms, 326, 120. Terraced planting, 150. Tetranychus mytilaspidis, 423. Tetranychus sexmaculatus, 423. Texture, importance in judging, 136. Thawing, of frozen fruit, 249. Thermal l^elts, 236. Thinning, of fruit, 323 ; advis- ability of, 282. Thomas, E. E., cited, 378, 449. Thomson, A. C, 68. Thorns, 51. Thorn-stabs, 321. Thrips, discussion of, 425. Tibbet, Luther C, and wife, 17, 18. Tillage, 165. Tincture of orange flowers, 338. Toadstool root-rot, 373. Tomocera californica, 410. Tools, for pruning, 225. Topography, as affecting frosts, 238. Top-working, 223, 92. Tortrix citrana, description of, 428. Tractors, for plowing, 168. Traffic, division of Exchange, 350. Training young trees, 100. Transit, time required for, dis- tance covered, 298. Transpiration, in fruit, 61. Trapping gophers, 456. Tree protectors, 157. Tree-ripes, 305 ; lemons, suscep- tible to black pit, 401. Trees, cost of, 359 ; number of, to the acre, 149. Triangular planting, 147. Trifoliata, susceptibility to frost, 242 ; as a root-stock, 153. Trifoliate orange, rare in California, 83. Tripeta ludens, 24 ; quarantine against, 109. Trunk rot, 399. Turgidity of rind, dangers from, 278. Twelve-spotted beetle, 430. Twig blight, 382. Twig-gumming, 367. Tylenchulus semipenetrans, 449. Types, of fruit, 123. Underwood-Simmons tariff, 9. University of California, 11. U. S. Department of Agriculture, citrus hybrids distributed by, 79 ; influence on industry, 11. U. S. Supreme Court, decision in pre-cooling case, 298. 520 Index Vaile, R. S., 455. Valencia orange, how pruned, 212; sweating of, 282 ; origin of and conditions best suited for, 70 ; pollination of, 55. Varieties, descriptions of, 65 ; bib- liography, 485. Vegetables, grown between trees, 159. Ventilation, for stored lemons, 308. Verrucosis, 395. Vesicles, as affected by frost, 274 ; arrangement of, 60. Vetch, as host for cottony mold, 383 ; common, as cover-crop, 182 ; hairy, as cover-crop, 182. Vicia sativa, as cover-crop, 182. Vinegar, from oranges, 336. Wages, of lemon pickers, 317. Wagons, 304. Wallace, J. C, 16. Washington Navel orange, descrip- tion of, climatic and soil condi- tions best suited to, sporting habits, sub-varieties, 66 ; com- position of, 62 ; seedlings of, 59 ; production of seeds in, occur- rence of normal embryo sacs in, 56-57 ; pollination of, 55 ; his- tory of introduction, first ex- hibited in California, 19 ; present location of two trees first brought to California, 23 ; sports of, 128 ; how pruned, 207. Wash water, disinfection of, 291. Water, amount necessary for irri- gation, 188 ; application to young trees, 158 ; disposition of waste, 150, 144 ; loss of, from fruit, 61 ; average cost of, 361 ; methods of application, 198 ; time of application, 195 ; temperature of, 196 ; methods of distribution, 193; lifting, for irrigation, 193; underground, laws in regard to, 192 ; cost of, 193 ; sources of, 192; measurement, 191. Watering seed-beds, 391. Water right, 142 ; cost of, 359. Water supply, importance of, 357 ; for irrigation, 141. Webber, H. J., 79. Weeds, as hosts for scale insects, 404. White, A. S., 19. White fly, quarantine against, 109. Whitewash, for pruning wounds, 228 ; prevents sunburn of bark, 219. Wind, as affecting frost, 233, 235 ; as affecting irrigation, 188; arti- ficial, as frost protection, 248 ; causing blemishes of fruit, 320; effect on fumigation, 448. Windbreaks, 37, 38. Windfalls, 324. Winds, effect on trees, 36. Wire baskets, 250. Wither-tip, description of, 380. Woglum, R. S., 433. Wolf & Massey, 393. Wolfskin, Louis, 17. Wolfskin, William, first commer- cial orchard, 2. Wood, structure, 46. Woodworth, C. W., 446; dosage table, 450. Workman, C. R., 74. Works, J. D., cited, 161. Wounds, dressings for, 226 ; heal- ing of, 49. Wrappers, redeemable for pre- miums, 351. Wrapping, value in judging, 138. Xanthoxylum americanum, 42. Yellow scale, discussion of, 414. Yellow spotting of oranges, 398. Yields, 127, 129, 359; lemon and orange compared, 191 ; average obtained, 362. Yuma, citrus planting at, 23. Printed in the United States of America. North Carolina State University Libraries CITRUS FRUITS AN ACCOUNT OF THE CITRUS FRUIT " nil S02787813 L