TEXAS AGRICULTURAL EXPERIMENT STATION C. H. McDOWELL, Acting Director College Station, Texas BULLETIN NO. 682 AUGUST, 1946 MHUUNHMYflmDE$ASAB&fiHmRTHE ESTIMATION OF HAIL LOSSES LESLIE R. HAWTHORN Formerly Horticulturist Substation N0. 19, Winter Haven, Texas Ll l‘? A Y L ,5." & EVL. QQLLLQUQ; i}? IEXAJ: AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS GIBB GILCHRIST, President VB1-946-4M-L180 [Blank Page in Original Bulletin] Hail causes some loss to onions every year in Texas both by injury to the foliage and t0 the bulbs in a crop near harvest. Foliage injury may vary from slight to the entire loss of foliage. The final crop damage has been diflicult to estimate by growers and hail insurance adjusters. To determine the efiect of foliage loss on yield, definite amounts of foliage were removed at evenly spaced intervals before harvest in 1943 and 1944. Results were remarkably similar in both years and with two varieties, Yellow Bermuda and Babosa, used in 1944. Hence, it is believed that the results presented in this bulletin will enable the onion grower and the hail insurance adjuster to estimate more reliably the actual loss incurred from hail injury than has been possible in the past. The most critical period for loss of foliage to occur is the week in which bulbing is beginning. In 1944, a total loss of foliage in that week caused a 100 percent loss in the valuable U. S. No. 1, jumbo and medium sized bulbs of Yellow Bermuda, and a 95 per- cent loss in the Babosa variety. The earlier in the life of the plant prior to bulbing that injury to foliage occurred, the less serious was the loss in yield. Likewise, the longer after bulbing started foliage was removed, the less the yield loss attributable to foliage injury. Obviously, after bulbs are forming, losses in yield can occur from direct injury to the bulbs themselves, and so the total loss due to both foliage and bulb injury in the week before harvest could be very great. The percentage loss in yield due to complete removal of the foliage was, with but few exceptions in both years, and with both Yellow Bermuda and Babosa alike, always significantly greater than the percentage loss in yield due to the loss of only half of the foliage. a CONTENTS Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Review of Other Work . . . . . . . . . . . . . . . . . . . . . . . . . . - - . . . . . . . . . . . . . . 5 Method of Procedure . . . . . .L . . . . . . . . . . . . . . . . . . . . . .; . . . . . . . . . . . . . .. 6 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Effect of the Removal of Foliage on Yield . . . . . . . . . . . . . . . . . . . . . . .. 9 Effect of the Removal of Foliage on Percentage Losses . . . . . . . . . . .. 9 Effect of the Removal of Foliage on Grade . . . . . . . . . . . . . Q . . . . . .. 14 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..' . . . . . . . . . 17 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 BULLETIN NO. 682 AUGUST, 1946 DEFOLIATION STUDIES AS A BASIS FOR THE ESTIMATION OF HAIL LOSSES IN ONIONS by Leslie R. Hawthorn, Formerly Horticulturist Substation N0. 19, Winter Haven, Texas From 1931 to 1940, Texas had an average of 61,470 acres in onions annually (10). This was nearly one-half of the average total of 129,870 acres for the entire United States during the same period. In terms of dollars, Texas onions had a value of $3,789,800, or more than one-fifth of the average annual total of $18,038,600 for all the onions in the whole country. Not only do onions represent a large total investment in Texas, but they are among those crops in which the investment per acre is also high. Such a situation increases the grower’s risk from weather hazards. One of the most disastrous climatic occurrences which can turn within a few minutes a potentially profitable field of onions into a serious loss is a hailstorm, which is most likely to occur during the season when the onions are maturing. This means that the grower has already made most of his production investment. Even though hail occurs nearly every spring in some onion growing locality, the acreage actually affected is usually small. Because the potential loss to an individual is high, it is natural for growers to take out hail insurance and thus reduce their risk. This type of insurance is increasing in volume each year. On the part of bothgrower and insurance adjuster, however, there is often a lack of information on which to determine how great a loss has actually occurred. Their problem has not been easy. For example, suppose that an early hailstorm entirely removes the foliage of a crop of onions which should within a week or two begin to bulb. What is the loss? Is it total? Given reasonable freedom from thrips, pink root and other troubles, can such a crop come back and give the grower a Worthwhile harvest? The studies reported here were conducted with the view of answering such questions. Review of Previous Work Although some study has been made on some grain crops of the effect of hail injury, both natural and simulated, practically no published in- formation seems to be available for onions. A preliminary report of the work herein described was published in 1943 ('7). The Illinois Agricultural Experiment Station studied the effect of hail injury on the corn plant in the 1920’s (1, 2, 3). In the years which immediately followed, similar experiments with flax were reported from the South Dakota Agricultural 6 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION Experiment Station (8). Considerable work with corn and small grains, involving a number of diverse treatments was also carried out in Iowa during the same general period (4, 5), and in 1941, a report came from Canada on simulated hail experiments with grain crops (9). None, if any, of these reports has any direct bearing on onions, but it is interesting to note that essentially all the methods employed consisted of the removal of parts of the plant or making them non-functional, and that yields were usually reduced as a result. Method of Procedure To simulate a complete loss of foliage due to hail, the entire foliage of onion plants growing on the Winter Garden Station (Substation No. 19) was cut ofl’ at the neck, just below the base of the lowest blade (Figure 1). In another treatment, the foliage was removed at a point approximately one-third of the way up the plant from the base of the lowest leaf; in this treatment, half of the foliage was considered lost. Since each leaf is larger at the base than near the tip, it is apparent that there is more leaf surface per linear inch of leaf towards the base than there is towards the tip, hence the removal of the foliage at the point indicated is believed to approximate fairly closely a 50 percent loss of foliage. The cutting was done with grass shears. These treatments were purposely simple and of a type which could be repeated with reasonable accuracy. They were based on the easily observable fact that hail either actually removes foliage or, by injuring it, makes it non-functional. In 1943, these treatments were carried out on the same day of each week beginning on February 26, six weeks before harvest. The removal of foliage in 1944 was begun on February 4, eleven weeks before harvest. Because the differences between the results of the treatments made during the early weeks of the experiment in 1943 had been slight com- pared to the differences between those made in the later weeks preceding harvest, the treatments in 1944 were spaced two weeks apart until three weeks before harvest, after which they were made weekly. Thus, the treatments were made six times in 1943 and seven times in 1944. It perhaps should be pointed out that it was practically impossible to estab- . I lish a final arrangement of plots before starting the experiment each year, as at that early date it was not possible to predict how many treat- ments there would be. Weather conditions can cause such variations in the time of maturity from year to year that weekly treatments such as this experiment involved might easily have to be continued several weeks more or less than were originally anticipated. Since twelve plots were used each week, the possible total number of plots needed might vary greatly. Thus it seemed better to select a uniform patch of onions and gradually move across it with the weekly or fortnightly treatments. A plot consisted of a single row of 100 onion plants, and each treatment was carried out in four separate places at each time. Adjacent to each of the two differently treated rows, an uninjured row was always left as a check. Thus, by harvest time in 1943, there were 72 plots in all, Lflln4.n1- . . . DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 7 Figure 1. Amount of foliage removed in simulating hail injury to onion plants. Left, entire loss of foliage; center, half of foliage lost; right, uninjured check. .8 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION and in 1944, a total of 84 plots. In both years, the onions were harvested in April at a time when approximately 50 percent of the tops in the check plots had fallen over or had softened at the neck. The harvest date in 1943 was April 10, and in 1944 was April 21. » In 1943, the experiment was conducted in a good uniform field of Yellow _ Bermuda onions. In 1944, two replications were placed in a patch of Yellow f‘. Bermuda onions and twoin an adjacent planting of Babosa. Babosa was originally introduced as Early Grano. Unfortunately, in the second year, certain conditions due to the war made it impossible to have four replica- tions all in Yellow Bermuda, or all in Babosa, or what would have been very desirable, four replications in each of both varieties. In both years, the Yellow Bermuda variety came from a fairly good strain of commercial seed, although as the data in some of the tables show, the strain grown in 1944 did not have such a high proportion of U. S. No. 1 onions in the uninjured check plots as did the strain grown in 1943. The Babosa variety was grown from a strain especially selected in 1942 by the Winter Garden Station for earliness and uniformity. Table 1. Yield of onions from which all or half of the foliage was removed at intervals. 50-pound bushels per acre. W k Foliage uninjured Half of foliage removed All of foliage removed hellfire? U. S. N0. 1 U. S. N0. 1 U. S. No. 1 harvest treatment Jumbos Culls Total Jumbos Culls Total Jumbos Culls made and Boil- and Boil- and Boil- mediums ers V mediums ers mediums ers 1943 Yellow Bermuda 6 505 23 12 540 309 46 23 378 112 87 31 5 606 14 14 634 310 35 18 363 99 82 35 4 491 17 16 524 289 40 27 356 133 49 24 3 441 21 23 485 231 52 34 317 1 37 50 46 2 506 22 19 547 293 50 18 361 241 56 24 1 437 29 29 495 422 25 42 489 349 36 28 1944 Babosa and Yellow Bermuda 11 426 22 22 470 343 25 15 383 193 50 11 9 423 16 36 475 346 27 11 384 112 67 10 7 457 22 25 504 287 40 20 347 61 66 23 5 364 35 22 421 175 49 30 254 10 40 39 3 404 18 17 439 212 50 20 282 52 52 21 2 400 22 13 435 265 45 12 322 142 49 22 1 369 35 7 411 262 44 18 324 237 42 20 1944 Yellow Bermuda 11 375 34 36 445 308 34 23 365 144 74 13 9 353 26 65 444 285 45 17 347 60 88 9 7 384 35 30 449 228 67 16 311 17 97 26 5 320 44 19 383 123 77 31 231 0 46 38 3 366 28 19 413 180 73 26 279 26 68 13 2 291 38 8 337 193 69 l0 272 112 70 17 1 238 55 4 297 185 68 l0 263 150 68 18 1944 Babosa 11 476 10 8 494 378 16 7 401 242 27 9 494 7 508 408 10 6 424 163 46 11 7 628 10 19 557 346 13 23 382 105 35 20 5 409 26 25 460 228 20 29 277 19 34 39 3 441 9 15 465 245 27 13 285 78 36 28 2 507 7 8 533 337 21 15 373 172 27 27 1 502 15 10 527 338 20 27 385 324 17 22 ' DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 9 EXPERIMENTAL RESULTS Effect of the Removal 0f Foliage on Yields i Yields in bushels per acre as calculated from the averages of the actual plot yields obtained in the various treatments are presented in Table 1. f Yields obtained in the check plots where the foliage was uninjured show ¥>in both years that the experiment was conducted with onions having good productivity. The Yellow Bermuda yields for 1943 and the combined Yellow Bermuda yields for 1944 were based, of course, on four replica- tions, but as explained in the section on Method of Procedure, the yields inf each variety separately in 1944 were necessarily based on only two 1 " replications. _ ~_ ‘In all the tables and graphs, as well as in the discussion of the various results throughout this publication, considerable attention is given to .. the sizes and grades into which the harvested onions were classified. s This is because in commercial practice the type of onion produced has 1 considerable bearing on a grower’s returns. In a year when production greatly exceeds demand, a grower often finds that the only grades he can sell easily are the U. S. N0. 1 onions of jumbo and medium size, but a in a year when the demand exceeds the supply, even the culls may be sold. Thus, in any situation involving an estimation of the yield losses ‘_ due to hail injury, pertinent facts as to the probable effect on yields of ’ the different grades and sizes of onions might be most important. _ The yields given in Table 1 lead to the obvious conclusion that in both l‘ years the removal of either half of the foliage, or all of the foliage, nearly _ always resulted in a decided loss of the U. S. No. 1 yield of jumbo and if medium size, as well as similar loss in total yield. Also, the results indicate jlrather plainly that a total loss of foliage was always more serious than i the loss of only half of the foliage. Figure 2 illustrates the type of i“ material harvested from some of the treatments. Elfect of the Removal of Foliage on Percentage Loss A Although the figures in Table 1 tell an interesting story in themselves, l they are not‘ wholly satisfactory for this study because insurance ad- justments are based on percentage loss. What percent of an expected crop did a grower lose? Tables 2, 3, and 4, therefore, give the percentage losses for the different grades or groups of grades of onions in both -» 1943 and 1944. With but few exceptions in both years and with both u varieties alike, the percentage loss in yield due to complete removal of foliage was always significantly greater than that due to a loss of just half the foliage. Another fact nearly as obvious, but probably far more important, v is that the loss of foliage in the fifth week before harvest was the most serious in both years (Tables 2, 3, and 4). The fifth week before harvest in these experiments corresponded in both {years to the time when bulbing " began in the bulk of the crop. 10 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION Figure 2. Babosa onions taken without selection from plots harvested the same day and after having received simulated hail injury at various earlier dates in 1944. Amount of foliage removed and the number of weeks before harvest that injury oc- curred: A—half, 11; B—all, 11; C——half, 3; D—all, 3; E—half, 1; F—all, 1; G and H-—uninjured checks. Note the variation in the amount of foliage as Well as the variation in size of bulb due to treatment. DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 11 The percentage losses in yield of ‘the combined jumbo and medium sizes of U. S. No. l onions by the removal of all or half of the foliage at intervals. v Half of foliage removed All of foliage removed 1944 1944 1943 1943 Yellow Varieties Yellow Yellow Varieties Yellow Bermuda combined Bermuda Babosa Bermuda combined Bermuda Babosa . . . . . . . . .. 195 178 20.6 54.7 616 492 . . . . . . . . .. 182 193 17.4 73.5 830 670 . . . . . . . . .. 372 406 34.5 86.7 956 801 38.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48.9 51 9 61.6 44 3 83.7 97 3 100.0 95 4 41.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.6 47 5 50.8 44 4 68.9 87 1 92.9 82.3 42.1 33 6 33.7 33 5 52.4 61.5 66.1 3.4 29 0 22.3 32 7 20.1 35 8 37.0 35 5 10.0 15.0 24.9 20.3 10.0 15.0 24.9 20.3 ' figures can also be used as a basis in this and the following tables for testing the differences be- iitagles in corresponding coluines. For example, one can compare fi res for Yellow Bermuda i here alf the foliage was lost, with those for Yellow Bermuds for 194 where all the foliage was ‘Table 2 brings together the percentage losses occurring in the most i, uable commercial grades, the combined jumbo and medium sizes of_ ons classifying as U. S. No. 1. With the exception of the treatment week before harvest, when most of the bulbs were practically ma- i , the differences in percentage loss sustained between onions losing :1 half and those losing all their foliage were always considerably re than the least amount required for significance. The highest loss 31943, 83.7 percent, was that suffered by the Yellow Bermuda onions 'ch had all of their foliage removed five weeks before harvest, just - n most of them were beginning to bulb. In 1944, when two varieties " e observed, the most serious loss occurred to both in the treatment i I e when bulbing began as in 1943, the only difference being that losses j 1944 were greater. Yellow Bermuda suffered a loss of 100 percent 211944, and Babosa was very close behind with a 95.4 percent loss. ere all of the foliage was removed eleven weeks before harvest in y‘ Babosa sustained a 49.2 percent lo-ss in its U. S. No. 1 yield of 1| and medium sized onions combined, and Yellow Bermuda as much ; 61.6 percent. Injury to foliage just one week before harvest was the ‘ st serious, 20.1 percent of the combined jumbo and medium yield of 110w Bermuda in 1943, and 35.8 percent forthe two varieties combined 1944. {Where only one-half the foliage was. cut off, the worst losses were still ;-- in those onions receiving treatment when bulbing was first beginning e weeks before harvest. In 1944, the smallest losses in" this treatment i’ urred when the onions were injured eleven 'weeks before harvest. bosa, with one-half of its foliage cut off at that time, ended the sea- with a 20.6 percent loss in the important combined jumbo and medium 12 yield, while Yellow Bermuda lost 17.8 percent. A removal of only h p, the foliage just one week before harvest in 1944 caused a loss not s’ nificantly less than where "all the foliage was removed. In 1943, remov j; of one-half of the foliage one week before harvest caused a negligible l i Table 3. The percentage losses in yield of the combined jumbo, medium and boilers of U. S. No. ~_ caused by the removal of all or half of the foliage at intervals. ff BULLETIN NO. 68,2, TEXAS AGRICULTURAL EXPERIMENT STATION 0s l Half of foliage removed All of foliage removed Weeks before 1944 1944 harvests 1943 1943 treatment Yellow Varieties Yellow Yellow Varieties Yellow made Bermuda combined Bermuda Babosa Bermuda combined Bermuda 11 . . . . . . . . .. 17.9 16.4 18.9 . . . . . . . . .. 45.8 46.7 9 . . . . . . . . .. 15.0 12.9 16.6 . . . . . . . . .. 59.2 60.9 7» . . . _ . . . . .. 31.7 29.6 33.3 \ . . . . . . . .. 73.5 72.8 6 32.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.3 . . . . . . . . . . . . . . . . . . . . 5 44.2 43.0 45.1 43.0 70.8 87.5 87.4 4 35.2 . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . 64.2 . . . . . . . . . . . . . . . . . . . . . . . . -. 3 38.7 37.9 35.8 39.6 59.5 75.4 76.1 2 35.0 26.6 20.4 30.4 43.8 54.7 44.7 1 4.1 24.3 13.7 30.8 17.8 30.9 25.6 Difference necessary for significance at5% level.. 9.7 13.6 24.7 18.9 _9.7 13.6 24.7 In most years, the U. S. No. 1 onions of all three sizes, jumbo, mediumr. and boiler, are readily marketable. Table 3 shows the percentage losses in these combined grades when the growing crop has suffered the injuries-E already indicated. The results, as given in Table 2- for jumbo and medium _ sizes, have the same trend, but are lower in almost every instance. When: total yield i_s considered, Table 4, the percentage loss is still lower, but Table 4. The percentage losses in total yield, including culls, of onions caused by the removal of all of the foliage at intervals. Half of foliage removed All of foliage removed . Weeks ' before . 1944 1944 < harvest 1943 _ _ 1943 _ Yellow Varieties Yellow Yellow Varieties Yellow ‘ . Bermuda combined Bermuda Babosa Bermuda combined Bermuda B , 11 . . . . . . . . .. 18.5 18.0 18.8 . . . . . . . . .. 46.0 48.1 9 . . . . . . . . .. 19.2 21.8 14.7 . . . . . . . . .. 60.2 64.6 ~T 7 . . . . . . . . .. 31.2 30.7 31.4 . . . . . . . . .. 70.2 68.8 7' 6 30.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 .9 . . . . . . . . . . . . . . . . . . . . . . . . . 5 42.7 39.7 39.7 39.8 66.2 78.9 78.1 :1. 4 32. 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60. 7 . . . . . . . . . . . . . . . . . . . . . . . . ’ 3 34.6 35.8 32.4 38.7 52.0 71.5 74.1 . _ 2 34.0 26.0 19.3 30.0 41.3 51.0 40.9 5 1 1.2 21.2 11.4 26.9 16.6 27.3 20.5 Difference " necessary for v significance ~ at5% level.. 8.9 11.7 19.6 16.5" 8.9 11.7 19.6 w. 13 DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION 0F HAIL LOSSES- Tw *2 5am 5o: g wk: :5 v2 w» wk: flow v2 ......:o>o: Q5 Hm vacuuming ‘. .5: wkwmmooon oocokowmfl m? 9% W3 $3.3“ Q5 m...» Q8 mfiw mbm 18 haw m? H 2K mam >3 5.? m?“ 9E. m? 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I mmonmm xvi-Com vwcfiiou muss-Sm mwonmm avsniwm: wwfinfioo wwsfihwm wmonwm mwucium ugEEoo wwsniom 30:9: mflfiifiw 30:0,? 32E? $$wim> 30:»? 30:9: wofioimkw 30:0? “Rain: n33 m2: mi: v.83: 3A3 3A3 3A3 3.53 nut/ens: @933: 3:4 ufi/ofioh wwfifio: mo :3: ©3233: Qmqfioh éwaioefi 3* audio: uo 133:0.- o-S u: :23.- a mu mofim EEwoE ca: .553. .3 mowuhw ~ 62 .m .D tout-Eco E 3:1». 23:5 u: E3.» :33 o5 we mount-venom .m 03am. f five weeks before harvest produced no jumbos or medium sized onions 14 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION the trend is still essentially the same. The reduction in percentage losses from Table 2 through Table 4 is due to the fact that the removal of foliage which caused loss of yield in U. S. No. 1 jumbo and medium sized onions usually caused an actual increase in yields of boilers and culls, Table 1. This leads to a consideration of the effect that the treatments had on the distribution of the onions in the various recognized grades. . ..._. _....__ m. -._.m..-.I._i\ mlmaazmam _ m. ._.._I_. LM-A _ m _ . Effect of the Removal of Foliage on Grade As shown in Table 5, a complete loss of foliage at any time and with y both varieties, reduced the percentage of onions falling in the U. S. N0. 1 grade of jumbo and medium sizes. The reduction in the proportion of these sizes was. greatest both years in those onions injured five weeks pre- ceding harvest. The Yellow Bermuda onions which lost all their foliage of the U. S. No. 1 standard at all in 1944. Only 20.7 percent of the total ' yield of Babosa onions receiving this treatment were placed in the jumbo and medium grades. The losses sustained in 1943 were not so serious in. this respect, but even then only 45.9 percent were classified in the com- ‘f bined jumbo and medium sized grade of U. S. No. 1 onions, as compared . with 95.6 percent when the onions remained uninjured, Table 5. A re- moval of only half the foliage did not reduce the percentage of U. S. a No. 1 jumbo and medium sized onions nearly as seriously, although even that treatment when carried out at the initiation of bulbing, caused suf- ficient reduction to mean financial loss to a commercial grower. The j removal of only half the foliage of either variety nine to eleven weeks before harvest in 1944, and as late as only one week before harvest in either year, did not reduce the proportion of these more highly marketable grades to any appreciable extent. In the former instance, the plants ap- parently had time to recover in the fairly long period before harvest; in_ 1 the latter instance, the crop was probably so nearly made that the final stages of bulbing and maturing could be carried out satisfactorily with ‘ the remaining half of the foliage. it In contrast, the percentages of the total yield falling in the boiler grades * almost invariably increase as a result of foliage removal, and where 5 all the foliage is removed, the percentage of boilers is even more noticeably increased than where only one-half of it is lost, Table 6. In the treatment f‘ producing the most effect, one finds 9.6 percent of the onions in 1943 f classified as boilers where one-half of the foliage Was removed, and 38.0 percent where all of it was taken, as compared with only 2.2 percent p’ in the uninjured plots. With Yellow Bermuda in 1944, although the uninjured plots had a larger percentage of boilers than in 1943, the percentages in "the two injured treatments were correspondingly greater. The general effect for both years was the same. Babosa also showed-i very much the same trend in 1944. I The effect of the various treatments on the cull grade was similar top but not so striking as that described above for the boiler grade, Table 7. 3033 30.33 . $335 3033 3.033 303w 303w 303w 3513mm» 40333». 401033.20 403308 4230i 43.3.3333. 4.33391 £03543 43.3333 40:32.3 $034553» 0033033300 $034330» wmvomm Wand-am» 003333333 @3333» 333.8» M03353» 00303350 005E.» wmvow» 33 3.3 90 M.0 .. 0.w 0.w 3.0 .. 30.3 wM.0 0.3 0 . . . . . w.3 w.0 3.3 . . . . . . . .. 90 3w.0 M.3 . . . . . .. ww.3 00.3 M0.0 .3 . . . . . . . .. 3.3 9w 3.w . . . . . . . .. 33w M3.w w_3 . . . . . . . .. 33.0 00w 3M.w 0 3.w . . . . . . . . . . . . . . . . . . . . . . . . . .. 3M.M . . . . . . . .. . . . . . . .. w9w . . . . . . . .. . . . . . .. w MM ww 33.w w_3 0.0 30.w wmnw 9M ww.0 33.0 03.0 w90 W3 w.M . . . . . . . . . . . . . . . . . . . . . . . . . .. 33.M . . . . . . . . . . . . . . . . . . . . . . . . . .. 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Q 238.60 m» w 03033031.... ww 30w w.0 0.0 w.w 30.0 w.0 0.0 ww 30w w.0 0.0 .3503» 3. 363625.32... 3. 338 33:3 333.3 3. 3333i 3: 335 33: 5.33m 3. 3333i an w 25:33 3 335 3.3.55: c3. 30:33am u» 3:33.535. 3333mm.“ 333030223 3.3»: o3. 3o33mma 36504323 >333. 3350a 3.335423 Q3236 3033 3033 3033 3533.... 303w . 303w 303w 3333.436» 423333 43303335 £03302 £033.23 40103323 4.3333: 4.03308 133333393 0363302 @0355» 00533350 02893» 3x53.» 303.3333» 0033033323 30038.5» 305a...» @3533» 0233.32.33 W333i» 3035c...» 33 . .. 3.3 w_3 3a . ... w.0 Ga .3 3.w ma w.» 0 .. . . 90 33.0 3.3 .. . 1 M.0 3.0 3.3 . w.w w.3 w.0 .3 . . . . . .. w.0 0.3 w.3. . . . . . . .. w.0 w.3 0.0 3w.w 30.0 3M.w 0 M.M . .. . . . . . . . . . . . . . .. 0.3 . . . . . . . . . . . . . . . 3w.w w M.M w.M w.0 w_3 w.0 33w 3w.3 30w 30M 3w.w 3w.M 3M.w 3 w_3 . . . . . . . . . . . . . . . . . 90 . . . . . . . . . . . . . . . . . .. 33.3 . . . . . . . . . . . . . . w 3.3 w.0 3.0 w.M 30.3 3.3 0.w 3.0 30.3 30.0 3M3 30.3 M w.w w.0 M.3 w.0 w.0 w..3. w.3 3.0 9w 30.w w.0 33.0 3 w.0 3.3 3.w 3.0 w.0. w.0 ww 90 0.0 0.3 3.0 0.3 30333023323 swnmmwuww 33. m3 30.50am n3 w Q 30/533... 0.0 w.0 0.3 0.3 0.0 w.0 0.3 0.3 0.0 w.0 0.3 0.3 91 SEISSOT 'IIVH JO NOIILVWILSEI H01 SISVH V SV SEIICIIILS NOLLVITOJEIG \ 16 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION Again, the treatment made when bulbing was beginning had the most market effect-at least in 1944. There were about 5 percent of culls for the uninjured onions of both varieties, from 10.5 to 13.4 percent in the cor- responding onions from which half the foliage had been removed, and from 42.5 to 45.2 percent where all the foliage had been cut off, Table 7. The last mentioned percentages were higher by a significant margin than any others in either foliage removal treatment of any other Week. ..............5!3‘-Y' l g. mam‘ mms a. mamas aoimms raptor Balances g sums swarms. norms _nexu»svo»ss-eieq¢ ._ _ g mew. rm.» xrotamzm sums a t 1w 1 ‘i 1 a z l I a E i 5 a 1 4w Figure 3. Percentage losses in yields of Yellow Bermuda and Babosa onions as a result of foliage removal at varying periods before harvest in 1944. DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 17 DISCUSSION The results of these experiments were not only clear-cut but, in spite of the change in the timing of the treatments and the use of an ad- ditional variety of onion in the second year, exhibited the same definite trend each year. Analyses of variance simply confirmed statistically what was already apparent. The F value for the treatments in all of the r v o r ¢ s a 0 a a o a v o n __ ~ 1 ~ W a a s a $ s s g Figure 4. Percentage losses in yields of Yellow Bermuda onions as a result of foliage removal at varying periods before harvest in 1943 and 1944. 18 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION many analyses of variance which were made, was always far in excess A of what was necessary for significance at the 1 percent level. As might ; be expected, this does not mean that the difference between every pair of means was always large enough to be significant. The unavoidable i, situation of having only two replications for each variety in 1944 was c unfortunate, and contributed to the greater values needed for significant . differences in many instances when the varieties are considered singly; The period when bulbing began was definitely established, at least in I 1943 and 1944, as the most critical time at which removal of the foliage . could occur. Figures 3 and 4 bring out this particular fact more clearly than the Tables already presented. In both figures it will be noticed that ,1 the peak losses with either Yellow Bermuda or Babosayor in any com- _, bination of grades, always occurred in the fifth week before harvest—l the week in which bulbing began. Both figures emphasize the similarity of pattern in all the curves. Figure 3 particularly, indicates the similarity in the performance of Yellow Bermuda and Babosa in 1944. It also shows, clearly the large difference in percentage losses resulting from the entire 1' removal of foliage as compared to the removal of only half, especially? in periods of three to eleven weeks before harvest. Figure 4 emphasizesi the similarity of performance of Yellow Bermuda in 1943 and 1944. Some bulbs of Yellow Bermuda are illustrated in Figure 5 just after they were pulled and without selection from the “five weeks before harvest” treat-ii ment in 1943. One does not have to consult the graphs to see that thei losses in yield from this treatment were great. In 1944, the losses were; even greater. It is necessary to point out that unpublished data of the Texas Ag ' cultural Experiment Station show that bulbing does not always begin exactly five weeks before harvest, even at one location or with one vai riety, but will usually vary from year to year, even within a variety l’ well as between varieties. At Winter Haven, such varieties as Yello Bermuda, Crystal Wax, Early Grano or Babosa, usually begin bulbi between March 1 and 25, and the first two varieties are ordinarily ha _ vested between April 10 and 30. In general, an early beginning of bu F; formation is followed by an early harvest, but in some years adver Weather conditions, such as low temperatures and cloudy days followi the beginning of bulb formation, may retard the development norma__ expected. At the other extreme, maturity may be hastened by unusuall favorable weather following conditions which have delayed the beginn". of bulbing. With Babosa, the time of maturity may vary greatly, ev though bulbing began in various fields at about the same time, beca at present the various strains of this variety differ widely in their de _ of adaptability to growing conditions in Texas. Some strains are ' ,_ capable of maturity before some time in May, irrespective of how ear bulbing began. This study does not prove conclusively that the date W11: bulbing begins is the most critical date every year, as other stages ' bulb development were not encountered. Apart from time to bulbin‘ it does seem logical, in view of the evidence collected, to believe t A. DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 19 Figure 5. Yellow Bermuda Onions harvested the same day in 1943 after receiving simulated hail injury at the time they were beginning to bulb five weeks before. Top, those which lost half of their foliage; center, those which lost all their foliage; bottom, uninjured onions. 20 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION ' the removal of foliage at the beginning of bulb formation is more serious than at any other time before or after that period. The earlier foliage,’ is removed before that stage, the more opportunity there is for thei plant to develop new leaves and to manufacture the materials from‘ which the bulbs are to be made. The later foliage is removed after: bulb formation has begun, the less growth needed for maturity afteri the foliage has been cut off. » ‘i A comparison of data in Tables 5, 6, and 7 reveals that although the; losses in the percentages of onions falling in the U. S. N0. 1 jumboi and medium sized grades were balanced by increases in both the boiler 3 and cull grades, the boiler grade usually accounted for the larger share. In 1943, in the uninjured check plots, an average of 9.1 percent of the, total yield classified as jumbos (over_ 3% inches diameter for a Bermuda onion) while the number of jumbos in any of the treated plots was neg-e ligible. In 1944, Yellow Bermuda had an average of only 0.9 percent jumbos in the uninjured plots, but none at all in the injured ones, while r Babosa had 8.1 percent jumbos (over 3 inches diameter for this type of onion) where there was no injury, and none to very low percentages where l foliage removal occurred. These facts concerning ‘jumbos and boilers? indicate that the chief general effect of foliage removal was a decrease in i the size of bulb, rather than an increase in the proportion of typical i“ culls. The cull pile did increase, and some cases rather noticeably, but these increases were due to improperly matured onions, often called “bottlenecks,” rather than to the more common culls, such as doubles, or seedstems. There were no increases in the latter types of culls in either year. The criticism might be offered that, had the treated plots been allowed to continue growing until fully mature, such severe losses as reported herein would not have occurred. This is probably true. Such a procedure, g however, would have defeated the purpose of this experiment, which was to determine the percentage of yield loss as based on a normal crop harvested at the normal time for any one year. Since the price of onions may be reduced later in the season such a delay might result in financial loss to the grower. One further point should be kept in mind, and that is the foliage losses g described in these experiments were not actually caused by hail, nor by 5i such imitative methods as breaking _and tearing the foliage with a whip, or by blasting it with marbles or some similar object. Actual hail, as well as - the artificial methods just mentioned, pound and mutilate the foliage more than the simple cutting by shears. It is also practically impossible to duplicate time after time any exact severity of treatment with the methods just mentioned. The danger of complications from decay are greater with hail, especially if the storm is followed by several days of a rainy weather. However, observations made in onion fields injured by ‘ hail would indicate that fair weather and dry conditions greatly reduce the danger from decay. DEFOLIATION STUDIES AS A BASIS FOR ESTIMATION OF HAIL LOSSES 21 It was already known before this particular study was started, that the removal of part of the onion foliage at transplanting time, as much as four to five months previous to harvest, would reduce the yield (6). In view of this, it was felt that the results would be subject to more accurate interpretation if they were caused by the consistent removal of the same amounts of foliage on each date of treatment. The rather definite pattern of results actually obtained indicate that this assumption was probably correct. However, irrespective of the ultimate merits of this or any other method of procedure, it is believed that one could, with the help of the data presented in this bulletin, arrive at a truer estimate of the percentage loss in the final yield of an onion field injured by hail than could be obtained by any other method known at this time. Foliage losses, of course, would have to be estimated by some system of leaf counting in a number of places throughout the field. Having determined the amount of foliage in- jury, then the approximate bulb losses attributable to that foliage injury or removal could be calculated. When a hail storm occurs only one to two weeks before the harvest, the developing bulbs as well as the foliage are likely to be injured. Losses due to such combined causes could be very great. In cases of this type, a separate estimate needs to be made of the losses suffered directly by the bulbs themselves due to cuts, bruises and decay, and this loss can be combined with any attributed to foliage injuries. It is believed that the grower and insurance adjuster now have a sounder basis than here- tofore on which to estimate this last mentioned loss. ACKNOWLEDGMENT The writer wishes to acknowledge the help and financial assistance of Craven, Dargan and Company of Houston. The author particularly wants to thank Hugh Harleston, their chief adjuster, who in both years gave unstintingly of- his time at harvest to supervise the many helpers, and to record the numerous data being collected. Without his untiring aid completion of the work might have been impossible. SUMMARY , .._~’._.,w.,.._ .___..-. . .. These experiments with simulated hail injury to onions of the Yellow .~ Bermuda and Babosa varieties were conducted in an attempt to obtain ‘which follow. In one treatment, one-half the foliage, and in a second treat- ment all of the foliage was removed at intervals varying from one to " eleven weeks before harvest in 1943 and 1944. From the various data i collected, the following conclusions have been drawn: 1. The percentage loss in yield due to complete removal of foliage was, i with but few exceptions in both years and with both varieties alike, always [ significantly greater than that due to the loss of one-half of the foliage. E 2. The most serious loss in yield in both yearsand with both varieties a a better understanding of the effect which loss of foliage has on the yields 22 BULLETIN NO. 682, TEXAS AGRICULTURAL EXPERIMENT STATION occurred with the onions which suffered foliage injury in the week in which they were beginning t0 bulb. Such losses amounted to 100 percent for Yellow Bermuda, and 95.4 percent for Babosa in 1944 in the valuablei U. S. No. 1 grade of jumbo and medium sizes, Where all of the foliage had been removed. The corresponding loss with Yellow Bermuda alone in 1943 was lower, but still serious, 83.7 percent. ' 3. The greatest reduction in the percentage of onions falling in the- class of U. S. No. 1 jumbo and medium occurred with the onions which suffered foliage injury in the week in which bulb formation was beginning. For example, in 1944 Babosa had only 20.7 percent of its bulbs by weight‘ classifying as U. S. No. 1 jumbo and medium grades in the plots in which all the foliage was removed during that critical week, as compared with 88.9 percent of the same grades of onions in the corresponding un- injured plots. 4. Although, as might be expected with plant material grown out-of- doors under partially controlled conditions, comparable data for the two, years were not identical, the general trends of the results for the two years A were remarkably alike, and also were similar for the two varieties, Yellow Bermuda and Babosa. LITERATURE CITED 1. Dungan, George H., 1928. Efiect of hail injury on the development of the corn plant. Jour. Amer. Soc. Agron. 20:51-54. 2. Dungan, George H., 1929. Artificial hailing shows damage to corn by storms. Ill. Agr. Exp. Sta. Ann. Rpt. 42:49-50. 1 3. Dungan, George H., 1931. Hail damages corn worst when plants are tasseling. Ill. Agr. Exp. Sta. Ann. Rpt. 44:57-59. . 4. Eldredge, John C., 1935. The effect of injury in imitation of hail damage on the dew velopment of the corn plant. Ia. Agr. Exp. Sta. Res. Bul. 185. 5. Eldredge, John; C., 1937. The eifect of injury in imitation of hail damage on the de- velopment of small grain. Ia. Agr. Exp. Sta. Res. Bul. 219. 6. Hawthorn, Leslie R., 1939. Cultural experiments with Yellow Bermuda onions under irrigation. Tex. Agr. Exp. Sta. Bul. 561. 7. Hawthorn, Leslie R., 1943. Stimulated hail injury on Yellow Bermuda onions. Amer. Soc. l Hort. Sci. 43:265-271. , _ a 8. Klages, K. H. W., 1933. The eifects of simulated hail injuries on flax. Jour. Amer. Soc. Agron. 25:534-540. 9. Knowles, Douglas B., 1941. The elfect of hail injury on wheat and other grain crops. University of Saskatchewan Agr. Res. Bul. 102. 10. U. S. Department of Agriculture, 1943. Statistics.