"7^ rr 
 
 Ci»cui*a No. 03. Rcvimt* Coition, »• 1 
 
 lev ti» CoiJ 
 
 United Sum iimp., 
 
 \U OK ICNTOMO 
 
 THE MOST IMPORTANT STEP IN THE CONTROL OF THE 
 
 BOLL Uli: ML. 
 
 W. D. II 
 
 the boll 
 
 i't in il ii third of the total i 
 
 3 thia ii b< en coi y less than normal. 
 
 ■ prinri] onal climatic con- 
 
 numbei rite 
 
 ■ conditions did nol 
 e crop I 
 inii.i. 
 
 nter the weevil 
 
 m will b . j n ,),,. 
 
 uring tl • i :ir points ■ 
 
 i .ii. 
 It ted out in pu the Department 
 
 lure that thi importai oiling the boll 
 
 ■ the plants from the fiel i ble 
 
 in neof th< • | 
 
 . lv 
 Much subsequent work I 
 •t ion. I 
 ■ 
 
 largely ■ mt of the practical dif- 
 
 .ii.l the scarcity of labor which 
 
 d with picking oul the crop. 
 
 " " f thi ty for pr • arly crop in i rder to 
 
 boll weevil an 
 
 Iture thai 
 
 of 
 
 ni ' ; p is 
 
 bu1 | 
 
 traction in the fall tt ,. r j 
 
 of fall 
 
 i uction. 
 
 In the fall of ' pri( ,_ 
 
 in the 
 '• An - found in Texas wh< 
 
 •n were grown. ■ , n crown 
 
in any direction nearer than 15 miles. Through an agent of the Bureau, 
 Mr. J. D. Mitchell, to whom great credit is due for the direct manage- 
 ment of the matter, arrangements were made by contract with the 
 farmers concerned, under which all the cotton plants were uprooted and 
 burned during the first ten days in October. Provision was also made 
 to prevent the growing of volunteer or sprout cotton. In this way an 
 opportunity was obtained for an ideal experiment to show what can 
 be accomplished by the procedure that is now recommended by the 
 Department. About 15 miles from the locality in which the experi- 
 ment was performed a considerable quantity (295 acres) of cotton was 
 grown. In this region the stalks were not destroyed in the fall, and 
 observations made here have been used as a check upon the experi- 
 mental area. The class of farmers is about the same in the two local- 
 ities. The experiment was performed at Olivia, in Calhoun County, 
 Tex., and the cotton utilized as a check was located at Six Mile, a set- 
 tlement across Lavaca Ba}', in the same count}'. 
 
 Mr. Mitchell visited the Olivia and Six Mile localities early in May. 
 1907. At that time, in the former area, extensive search revealed but a 
 single weevil. In the Six Mile localit}', however, the weevils were so 
 numerous that practically all the squares had become infested. Other 
 examinations were made, all of which showed the same advantage in 
 regard to freedom from the weevil of the area in which the stalks were 
 destroyed. On August 20 Mr. Mitchell found an average of over 10 
 bolls per plant at Olivia and only 3 bolls per plant in the check area. 
 
 The conspicuous results of the experiment, however, are revealed bj r 
 the increased yield shown after the cotton was picked. The average in 
 all fields at Olivia was 0.41 bale as against 0.15 at Six Mile. This 
 increase of slightly over a quarter of a bale per acre (to be exact, 0.26 
 bale) was due to the destruction of the stalks. In order to determine 
 the exact financial advantage to the farmers at the Olivia locality, a 
 calculation has been made on the basis of the separate sale of lint and 
 seed. At Olivia the crop following the destruction of the plants aver- 
 aged 615 pounds of seed cotton per acre, that is, 205 pounds of lint 
 and 410 pounds of seed. At the Six Mile settlement the average yield 
 of seed cotton per acre was 225 pounds, that is, 75 pounds of lint and 
 150 pounds of seed. It is evident that the work done in the destruc- 
 tion of th,e plants at Olivia resulted in the gain of 130 pounds of lint 
 and 260 pounds of cotton seed per acre. On the basis of a value of 10 
 cents per pound for the lint and of $12 per ton lor the seed, the increase 
 amounted to $14.56 per acre. This is about 29 times the cost of uproot- 
 ing and burning the plants the preceding fall, as shown by the actual 
 amount the Department paid for the work. 
 
 The full importance of the results just mentioned can not be realized 
 until it is understood that the. soil at Olivia is much less fertile than 
 that at Six Mile. Mr. Mitchell, who is thoroughly familiar with the 
 productiveness of lands in that part of the State, estimated that the Six 
 Mile land is at least a third more fertile than that at Olivia. This esti- 
 mate was more than borne out bj r the amount of seed produced at 
 the two places during the season of 1907. At Six Mile the average 
 height of the plants, determined by measuring, was 4 feet, while at 
 Olivia the average was 2.2 feet. The estimate recorded of the advan- 
 tage resulting from the work at Olivia is made without reference to this 
 difference in fertility. 
 
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Tin 1 praotii .il experiment, a* ha stated, return tially 
 
 _"' times the cosl of the n outlay. Under other conditions this 
 
 advantage would necessarily be smaller. The experiment was carried 
 on purposely to show the great advantage of fall destruction where 
 there are no other factors to interfere with the results. Where cotton 
 is less isolated than that at Olivia then- will be less effective results, of 
 course, on account of the influx of weevils from fields thai may not 
 have been properly treated, Nevertheless, such conditions could not 
 My obliterate all effectiveness, tn fact, only the most extreme 
 and exceptional conditions could possibly result in reducing the advan- 
 obtained in the exp< riment by more than 60 per cent. That means 
 that any cotton planter, by the process of fall destruction, can insure 
 himself an increased yield to the value ol -'10 per acre by a 
 
 Small amount of work at the proper time in the fall. 
 
 REA8JI >fi THE DESTRU< THE PLANT8 IN THK PALL. 
 
 There are four principal reasons why the process of fall destruction 
 
 recommended in this circular should be practiced universally by plant- 
 in infested regioi 
 
 First. — Fall destruction prevents absolutely the development of a 
 multitude of weevils which would otherwise become adult within a few 
 weeks of the time of hibernation. The destruction of the immature 
 9 of weevils in infested squares and bolls is accomplished, while 
 the further growth of squares, which may become infested later, i- 
 pre Vented. This stops materially the development of weevils which 
 would normally hibernal -study, and by thus decreasing the 
 
 number of weevils which will emerge in the spring the chances for a 
 successful crop the follow; n are very greatly increase d. 
 
 "itil. — A proper manipulation of the stalks will bring about the 
 destruction of a great majority of the weevils which are already adult. 
 This will be accomplished partly by causing the starvation of many 
 weevils before the natural time for hibernation, and partly by exposure 
 to severe cold during the fall and winter. 
 
 Third. — It has been shown conclusively that the bulk of the weevils 
 which survive the winter are those which reach maturity late in the 
 in. It is evident that the weevils that pass the winter and attack 
 the crop of the following season are among thos ( . developed latest in 
 the fall and which, in consequence of that fact, have not exha 
 their vitality by depositii for any considerable length of time. 
 
 Fall destruction of the plants, increasing the length of the hibernating 
 period, reduces many fold the number of weevils in the fields that 
 would Otherwise emerge in the spring to damage the cotton. 
 
 Fourth. — Clearing of the held in the fall makes it possible to prac- 
 tice fall plowing, which is not only the proper procedure in any Bystem 
 of cotton raising, but also greatly facilitates the early planting of the 
 crop the following spring. The groin i by this practice, 
 
 so that but. few placet are left to the weevils, and various 
 
 climatic conditions still further reduce the number of the survivo 
 
 DATA UPON W'FIK'n THE FOREGOING RT JED. 
 
 The reasons for fall tion given above are based upon a very 
 
 large amount of data from actual experiments and the work of various 
 planters. The information at hand was greatly amplified in a series of 
 
 A6— 
 
large-scale experiments carried on during the winter of 1906-7. Three 
 large cages (50 by '20 feet) were built over growing cotton at Dallas, 
 it, and Victoria, in Texas. In different compartments of - 
 nearly 70,000 weevils were placed; several thousand in 
 compartment. After the weevils were piaced inside, the plants were 
 removed from the first section about the middle of October. At regular 
 subsequent dates other sections were treated in exactly the same man- 
 ner. Consequently the results for each locality show exactly what a 
 farmer could have accomplished by the destruction of the plants at dif- 
 ferent times. The full results will be published in Bulletin 77, of this 
 Bureau, by Dr. W. E. Hinds and Mr. W. W. Yothers, who have had direct 
 charge of the work. In this connection it is necessary to call attention 
 to only a few features. 
 
 In practically all cases the smallest survival of weevils was found in 
 those cages from which the plants were removed at the earliest dates, and 
 the number of survivors increased regularly as the dates of destruction 
 became later. For instance, at Dallas out of between two thousand and 
 three thousand weevils in each cage, only 2.5 per cent survived when 
 the plants were removed on October 13; 4 per cent survived destru 
 of the food supply on October 10; G.2 per cent survived destruction on 
 October 19; 12.2 per cent survived destruction on November 6, and 
 14.7 per cent survived destruction on November 12. These figures indi- 
 cate that practical I if seven times as many weevils survived after destruc- 
 tion of plants on November 12 as survived after a similar destruction 
 on October 13. This is a most striking illustration of the effect of 
 early destruction. 
 
 In the cages at Dallas, Calvert, and Victoria, from which the plants 
 were removed in November, 14.26 per cent survived, while 4.41 per cent 
 survived removal of the plants in October — that is, the cutting off of 
 the food supply in November resulted in the survival of three times as 
 many weevils as survived when the work was done in October. These 
 figures are based upon averages of eight large cages at the three locali- 
 ties in which October destruction took place, as compared with seven 
 similar cages in which the plants were removed in November. 
 
 TIME FOR DESTRUCTION OF THE PLANTS. 
 
 It is naturally impossible to fix anj- date for the destruction of the 
 stalks which would apply to all localities and under all conditions. 
 The condition of the soil must be considered as well as the maturity of 
 the crop. While the condition of the soil can not be controlled, the 
 time of the maturity of the crop, except in extremely unfavoraM 
 sons, is largely within the power of the planter, since by early planting 
 of early maturing varieties the entire crop may he matured 'before the 
 usual time of picking of the first cotton from native seed. Neverth 
 whatever modifications are necessary in different localities and during 
 different seasons, they do not decrease the general strength of the 
 recommendations. 
 
 The proper time for the destruction of the plants in the fall is when- 
 ever the weevils have become so numerous that there is no pros 
 that any more cotton will lie made. It will be an easy matter for any 
 planter to determine this point by an examination of a few plants in 
 his field. Whenever it is found that all, or nearly all, of the squares 
 and some of the bolls are being punctured, there is no hope for 
 
 A6 — 22 
 
■.: am n ton. The farmer should tl^u wail until the bolla 
 
 . tlio plant opened, and destruction Bhould then 
 
 I 
 
 Tbi u nily lit- thai tli »uld be destroyed 
 
 in the fall u ! ng damaged, 
 
 in September mber. In the 
 
 j and in Louisiana the month of October would 
 be the proper time, tnmanj struction could and ehould 
 
 ould nol be thought that fall destruc- 
 tion will ■ aed. Even until much later 
 - in tht> remains of bol ng t<> the plants may In 
 i, but tl^ a value the longer i; rred. Bj 
 all mean ould take place before 
 struction al 
 
 loold ;il t id u Inn it has not been 
 
 mt< previously. 
 
 HE PLANTS. 
 
 common p cotton stalk- from the Gelds 
 
 byth . cutter (a wheeled cylinder provided with knives) 
 
 the fall destruction that Bhould be practiced to avoid 
 by the boll weevils. I'll" stalks ren aini ig in that case dur- 
 ing i. 3, which furnish an abundan 
 
 ild otherwise starve. Mi , the fact thai 
 
 this macl Iks into shorl pieces makes the necessary col- 
 
 ilt. 
 
 moving the plants from the 
 ground. tethod to be prefern 1. is to cut the roots 
 
 by the use of an ordinary plow. The 
 other is to pull o r provided with a 
 
 lOtch W h i the plant. The latter pi 
 
 the plants hav< en k i 1 1« ■■ 1 by frost. 
 When they are still green, or the ground is dry, it is frequently a ditli- 
 cult them wi vera. The Department's 
 
 ion, then plants should be plowed 
 
 out. lould be collected by 
 
 hand hi together in large hea] 
 
 w indrows. i lection Bhould t 
 
 befon Iry and have dropped off. Winn the 
 
 plant uprooting, all of the leaf- 
 
 h will dl B, remains to facilitate the burnil 
 
 If 
 
 • ut two weeks. If rains 
 
 iriod, it would undoubtedly be worth the 
 
 Tide oil sufficient to bring about the 
 
 I 
 It i- any trap row- to attracl such 
 
 i the burning. The weevil - have 
 
 but 1: • -! ruc- 
 
 tion of the main cr >p tb ' would probably he in all directions 
 
 and the numbers colled be trap mid consequently be 
 
 The time and i of propi o the 
 
6 
 
 hand picking of the weevils and infested fruit on trap rows would be a 
 considerable handicap to the method on many plantations. Neverthe- 
 less, on small places where suitable labor is abundant, traps could con- 
 veniently be left. In such cases they (should be situated on those sides 
 of the fields which are generally leeward. They should be examined 
 daily for weevils and infested squares and bolls, which should be 
 immersed in crude oil. After such collection for ten days, the trap 
 plants should be uprooted and burned immediately with the aid of 
 crude oil. 
 
 The suggestion has been made at various times that grazing the cot- 
 ton fields with cattle is in some cases equivalent to destruction in the 
 way that has been suggested. However, in many parts of the infested 
 area there are not sufficient cattle to accomplish the work, and, more- 
 over, in very many fields the cattle, by disseminating Johnson grass 
 and other plant pests, would undoubtedly do more harm than good. 
 At the same time the most thorough grazing always leaves a few green 
 sprouts or leaves upon which weevils may feed, and of course leaves 
 the stalks standing, so that the process of leafing, for the benefit of the 
 weevils, may continue indefinitely. Where the condition of the fields 
 permits and the supply of cattle is sufficient, grazing the fields should 
 be practiced, but this can not generally be the case in the infested area. 
 
 DIFFICULTIES. 
 
 The Department of Agriculture understands that there are some diffi- 
 culties in the way of a universal following of the recommendations 
 given in this circular. The principal ones are the almost universal hope 
 for a top crop and in the labor conditions consequent from the more or 
 less universal tenant system of producing the staple. These difficulties 
 are increased by the general scarcity of labor in the South, which is 
 becoming more and more a serious problem in raising cotton. 
 
 Planters in infested localities must understand that with the presence 
 of the weevil there is no longer an}' hope of a top crop. It is true that 
 after considerable cotton has matured, and after the plants have applied 
 their energy to the formation of seeds and lint, fall rains often stimulate 
 the production of a great number of squares. Many planters are misled 
 by this into the hope of gathering a large top crop. The joints of the 
 plant are short and the squares are formed rapidly and close together. 
 Though weevils may have been exceedingly numerous in the fields, the 
 presence of this abundance of food causes them to scatter, and they are 
 consequently temporarily somewhat less in evidence. In many cases 
 blooms appear and the hope for a top crop increases. Nevertheless, 
 this production of squares also contributes to the production of a large 
 number of weevils late in the season and just at the time for their suc- 
 cessful hibernation. As a result of this fact great injury is done to the 
 crop of the following season, with no gain whatever, or a very small 
 one, in the yield of the current season. From these considerations it 
 seems plain that within the weevil territory all hope of a top crop must 
 be given up and the destruction of the plants be practiced as early in 
 the fall as possible. 
 
 Another important difficulty lies in the tenant S3'stem. It is usually 
 the practice to terminate the work of the tenant with the picking of the 
 cotton, leaving the clearing of the field for the next cropper. At present, 
 after the cotton is picked the tenants frequently move to other planta- 
 
 A6 2? 
 
ti.ms or to other parts of the same plantation. It should noi be a dif- 
 ficult matter "Tor planters to induce their tenants to practice th< 
 
 action of the plants as the last step in the production of a crop. 
 
 In any case the plants ha\e t'> he removed before the ground can be 
 prepared for planting the following season; and the present recom- 
 mendation merely involves applying, at a time some months earlier, 
 the same amount of labor as is necessary in the spring. The best solu- 
 tion of the difficulty arising from the tenant system would be in the 
 inclusion, in the agreement between the landlord and the tenant, of a 
 provision which would bind the latter to dean the land thoroughly 
 before leaving it. 
 
 In a comparatively small area in BOUthwesten it might he 
 
 considered that there would he a further objection in the practice which 
 some farmers have of encouraging the growth of volunteer or seppa 
 cotton in the hope of procuring an early and inexpensive crop. As bas 
 been repeatedly pointed out by the Department of Agriculture, this is 
 beyond question the worst possible practice in weevil-infested regions. 
 The disastrous experii several counties in the southern portion of 
 
 the State during several seasons has abundantly demonstrated the force 
 of the warnings that have been issued from time to time. The staple 
 produced by volunteer plants is short, kinky, and undesirable. Before 
 the advent of the weevil the only reason for encouraging such growth 
 was to procure the first hale. Now. on account of its vi ry detrimental 
 bearing on the weevil problem, any attempt to raise cotton from volun- 
 teer cotton should by all means he discouraged. 
 
 The point may he raised that the burning of the plants in the fall 
 removes valuable fertilizing constituents and that the continuance of 
 the practice would seriously reduce the fertility of the soil. In refer- 
 ence to this matter, however, it must he stated that the present general 
 practice is to clear the fields hy burning the plants in the Bpring. 
 Therefore, practically the only additional draft upon the soil hy the 
 method recommended is in the burning of many of the leaves and a 
 portion of the roots. However, destruction of the plants can only take 
 place after many of the leaves have fallen, and. in other cases, when 
 the plants have become completely defoliated by the cotton caterpillar. 
 The fertilizing constituents in various parte of the cotton plant have 
 been carefully determined. 1 An estimate of the value of all the con- 
 stituents which could possibly be removed hy fall destruction, I 
 upon the schedule of trade values adopted by experiment station 
 
 . shows that the loss per acre would he very small. It is plain 
 that the planter could not only regain this small loss but actually 
 greatly increase the fertility of the land by the use of commercial fer- 
 tilizers, which would cost an inconsiderable amount in comparison with 
 the gain in the following crop, as a result of lessened damage hy the 
 boll weevil. In some Cases, of course, the removal of humus furnished 
 by the stalks may he more important than the removal of the fertilizing 
 elements. It is urged, however, that the cheapest and : ctive 
 
 way to add humus to the soil is by green manuring, whicl iving 
 
 more and more attention throughout the cotton belt. 
 
 As a matter of fact, the preceding objections are not necessarily 
 serious. They deal with general changes in cotton culture made o< 
 
 Bulletin 33 of tin i>:!j,- of Kxperiment Stations of this Department, pp. 
 SI to 141?. 
 
 A« 23 
 
UNIVERSITY OF FLORIDA 
 
 1262 09216 4929 
 
 Sary by the ravages of the boll weevil. As is beginning to be well 
 known to planters, it will not be possible for tenants to'work as much 
 land as formerly. More cotton will be produced by decreasi 
 and increasing the attention given to what remains. If I 
 the objections mentioned will largely disappear. 
 
 CONCLUSION. 
 
 Having studied and tested the methods of weevil control which hi 
 been hitherto recommended, the writer firmly believes that the 
 tion of the stalks in the early fall is the most effective method known 
 of actually reducing the numbers of the pest. This destruction will 
 cost but a small fraction of the expense necessary in the frequent pick- 
 ing up in the spring of the squares infested by the hibernated v 
 and is far more thorough as a means of reducing the num 
 weevil than is the practice of picking hibernated weevils from I 
 young plants. Early destruction of the stalks is essential to the great- 
 est success of any system of controlling the pest. All other p 
 recommended, though very valuable in securing a crop, are of tl 
 est value as they are followed in connection with this one prin itial. 
 
 Since the earliest investigations of the boll weevil made by this Depart- 
 ment, it has been recognized and pointed out by D». L. O. Howard that 
 this practice is of the first importance, and the experience of recent 
 years lias added but certainty to this conviction. A number of planters 
 have adopted it, and their work and the large-scale work by the Bureau 
 of Entomology have abundantly demonstrated its effectiveness. 
 must not be thought that the procuring of the immediate the 
 
 only thing to be desired. Early and complete destruction of Hip sta 
 is undoubtedly the most important single element insuring 
 the subsequent year. 
 
 Concerted action in fall destruction is, of course, desirable. The 
 greatest benefit will result only when whole communities adopt I 
 method. But no planter should hesitate on account of the indiffi 
 of his neighbors. The fact that weevils move about but little until the 
 time when the bulk of the crop is safe will assist materially in saving 
 one field though near-by ones have not been properly treated, ai 
 under such circumstances the success of the method in one field will 
 a powerful stimulus toward its general adoption the following season. 
 
 It is true that the recommendations contained in this circular involve 
 considerable change in the culture of cotton. Nevertheless the impor- 
 tant changes that have been brought about, up to this time, in the i. 
 of improved seed and fertilizers have also been revolutionary in tl ■ 
 character. It is hoped by the Department that the agencies assist 
 in this matter — namely, organizations of business men— will everywhere 
 devote the same energy toward encouraging the practice of what is, after 
 all, the most important step in maintaining the supremacy of the cott. 
 crop in the weevil territory. 
 
 Approved : 
 
 James Wilson, 
 
 JSecretary of Agriculture. 
 
 Washington, D. C, Septembers, 1908. 
 
 O 
 
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