the cotton aphid and will prevent the buildup of a light boll weevil infesta- 

 tion if applied in time and at frequent intervals. For a heavy boll weevil 

 infestation it might be necessary to apply benzene hexachloride with a 

 higher gamma isomer content, 

 (e) It has been definitely demonstrated that the planting of cotton late in the 

 season in the Laguna District of Mexico is unprofitable for the farmer. 

 Although insect pests can be controlled, the high populations at the time 

 make it necessary to apply insecticides twice as many times as in a 

 normally planted cotton field, thus increasing the cost. Besides, early 

 frosts will always constitute a menace to the late planted cotton fields 

 and might reduce the yields to such an extent that the final crop will not 

 pay for the cost of insecticides nor even for the high costs of cotton cul- 

 tivation in the Laguna District. 



1949 - Roussel, J. S., and J. C. Gaines. Comparison of calcium arsenates alone and 



mixed with organic insecticides for cotton insect control. J. Econ. Ent. 42(3):551- 

 552. 



In cage tests, commercial calcium arsenate and a special calcium arsenate 

 were equally effective in their toxicity to the boll weevil. 



1949 - Walker, R. L., Jr., E. C. Fife, and Floyd F. Bondy. Comparative effectiveness 



of chlorinated hydrocarbons against the boll weevil. J. Econ. Ent. 42(4) :685 -686. 



The results of these experiments show that 50 percent or more of the knock- 

 down and kill by each of the insecticides was effected within the first 24 hours. 

 At the end of 2 and 6 hours, the benzene hexachloride mixture had caused a sig- 

 nificantly greater knockdown and kill of weevils than had any of the other insec- 

 ticides. After 144 and 1 68 hours, toxaphene had killed or paralyzed more weevils 

 than the benzene hexachloride mixture, the difference closely approaching sig- 

 nificance. There was no major difference between these two insecticides at any of 

 the other counts. Both knocked down more weevils than any of the other materials 

 tested, except at the 2 -hour count. 



Methoxychlor killed or paralyzed fewer weevils at each interval of the entire 

 7 -day period than did any of the other treatments. No mortality occurred in the 

 untreated check plots. 



No rain fell during either of the tests. The mean temperature was 77°F. for 

 the period of the first test and 79°F. for the period of the second test. 



1950 - Bondy, Floyd F., E. C. Fife, R. L. Walker, Jr., and C. E. Jernigan. Profit in boll 



weevil control. S.C. Agr. Expt. Sta. Rpt. 2:68-70. Clemson. 



To determine the net profit from poisoning for boll weevil control, records 

 were made in 15 poisoned fields and 15 untreated fields in 1949. Five to 8 appli- 

 cations were made. Either a dust containing sufficient benzene hexachloride to 

 give 4% of the gamma isomer plus 5% of DDT, or a 20% toxaphene dust, was used. 

 The yield in the treated fields averaged 1,385 pounds of seed cotton per acre, as 

 compared with 493 pounds in the untreated fields, or a gain of 892 pounds. 



There was a net profit of $44.25 per acre due to poisoning for boll weevil 

 control. The weevil-punctured squares in the poisoned fields averaged 18%, as 

 compared with 73% in the nonpoisoned fields. Thirty-one more bolls were re- 

 quired to make a pound of seed cotton from the nonpoisoned fields than from 

 poisoned fields. Two hundred open bolls from the poisoned fields weighed 2.55 

 pounds, as compared with 1.88 pounds for the same number of bolls from the 

 nonpoisoned fields. 



1950 - Bondy, Floyd F., L. C. Fife, R. L. Walker, Jr., and C. E. Jernigan. Spray or 

 dust. S.C. Agr. Expt. Sta. Rpt. 2:70-71. Dec. Clemson, 



During the past year many farmers, ginners, and manufacturers have asked 

 for a comparison of sprays and dusts for boll weevil control. Sprayed and dusted 

 plots were adjacent to each other in about 1-acre test areas in several fields at 

 the Pee Dee station during 1949. Spraying gave control of boll weevils equal to or 

 better than dusting; yields were about the same by both methods. Spray materials 



48 





