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BULLETIN 1374, U. S. DEPARTMENT OE AGEICULTUEE 



of June, a few days before blooming started. Treatment of the 

 plats in the second group (plats 4, 8, 12, and 16) began in the latter 

 part of July. At that time the first bolls were about three-fourths 

 grown. In the third group (plat 18) poisoning began near the end of 

 August, when the infestation averaged 2.96 worms per boll. Appli- 

 cations were continued on all plats until nearly all bolls were open. 



In the beginning, records of infestation were obtained by examining 

 blooms. But after bolls developed this record was replaced by boll 

 examinations, which were made weekly. Figure 14 shows the devel- 

 opment of the infestation in blooms in the plats of group 1 and the 

 corresponding check plats. According to this record the treatment 

 caused a very noticeable check in the infestation. 



The progress of boll infestation, by groups of plats, is shown graphi- 

 cally in Figure 15. 



A general summary of the experiments is given in Table 48. These 

 records show definitely that the infestation was reduced by poisoning. 

 The earlier the treatment was commenced the greater the reduction 

 obtained. Treatment begun very late had practically no eifect, 

 as shown in Group 3, plats 17 and 18. The sudden rise in numbers, 

 of worms per boll in the plats of Group 2 (fig. 15) at the last examina- 

 tion was due to scarcity of bolls. Very few bolls were left on the 

 plats at this time. This, however, was an abnormal record, not 

 comparing with the previous showing of the plats. In the table, 

 therefore, the next to the last instead of the last examination is given 

 for plats 13, 14, 15, and 16, to show the maximum reduction in 

 infestation due to the treatment. 



Table 48. — Summary of poisoning tests, 1921 





Treatment 



Acres 



Date of application 



Num- 

 ber of 

 ap- 

 phear 

 tions 



Pounds 

 applied 



Infestation 



last 

 examination 



Per- 

 cent- 

 age 

 non- 

 pick- 

 able 

 cot- 

 ton 



Classification 



of lint 



samples 



Plat 

 No. 



First 



Last 



Total 



Per 

 acre 



Worms 

 per 

 boll 



Per- 

 cent- 

 age 

 differ- 

 ence 



1 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Calcium ar- 

 senate. 



Check 



Arsenite of 

 zinc. 



Check 



Arsenite of 

 zinc. 



1 

 1 



1.11 

 1.11 



1 

 1 



1.11 

 1.11 



1.07 

 1.07 



1.07 

 1.07 



2.16 

 2.16 



0.66 

 0.66 



0.66 

 0.66 













3.46 

 1.92 



3.82 



2.88 



3.22 

 2.44 



4.04 

 3.72 



14.16 

 11.66 



13.68 

 1 1.52 



6.98 

 6.8 



4.8 

 2.38 



4.18 



""44.'5 

 "24.1 

 "'212 

 ""7.'9 

 "60.1 

 "58."7 



'"¥.1 

 "W.l 



"24.'9 



9.3 

 3.3 



6.9 

 5.3 



8.0 

 6.0 



7.7 

 7.5 



11.0 

 6.8 



9.0 



4.5 



14.8 

 10.8 



6.7 



4.4 



7.0 

 5.5 



Middling. 



2 



June 15 



Aug. 23 



16 



152.5 



9.5 



Strict middling. 

 Do. 



4 

 



July 20 



Aug. 23 



8 



84.75 



9.5 



Good middling. 

 Do. 



10 

 11 



June 15 



Aug. 23 



16 



124. 25 



7.8 



Do. 



Strict middling. 



12 

 IS 



July 20 



Aug. 23 



8 



84.75 



9.5 



Do. 

 Do. 



14 



June 25 



Sept. 14 



19 



181. 25 



8.9 



Good middling 

 Strict middling. 



16 

 17 



July 24 



Sept. 14 



12 



112.0 



8.7 



Good middling. 



18 



Aug. 26 



Sept. 30 



9 



229.0 



11.8 



Strict middling. 



6 



7 



June 15 



Aug. 23 



16 



134.0 



12.7 



Good middling. 

 Strict middling. 



8 



July 19 



Aug. 23 8 



■■ ! 



60.0 



11.4 



3.14 



Good middling. 



1 These were the next to last examination. 



