1947 - Becnel, I, J., H. S. Mayeux, and J. S. Roussel. Insecticide tests for the control 

 of cotton boll weevil and cotton aphids in 1946. J. Econ. Ent. 40(4):508-5 13. 



The results of one experiment indicated that 2.88% gamma benzene hexa- 

 chloride controlled the boll weevil as effectively as did calcium arsenate or cal- 

 cium arsenate- 1% nicotine. However, results of another experiment indicated that 

 to compare favorably with calcium arsenate for boll weevil control, it was neces- 

 sary to use 5.17% gamma benzene hexachloride. Applications of mixtures con- 

 taining calcium arsenate and benzene hexachloride resulted in large increases of 

 aphids. The compatibility of these two materials was questioned. 



Bollworms and red spiders increased following applications of benzene hexa- 

 chloride, particularly following applications of 5.17% gamma isomer benzene 

 hexachloride. The use of conditioned dusting sulfur as a diluent for benzene 

 hexachloride prevented increased red spider infestations. 



Calcium arsenate plus 1% nicotine produced higher yields of seed cotton 

 than benzene hexachloride containing gamma isomer ranging from 1.44% to 

 2.88%. It was necessary to apply DDT to control bollworm in BHC -treated 

 plots. 



1947 - Brett, Charles H., and W. C. Rhoades. Boll weevil control with chlordane, ben- 

 zene hexachloride, and calcium arsenate dusts. J. Econ. Ent. 40(4):572-574. 



Field tests at Eufaula, Okla., during the season of 1946 showed talc dust 

 containing 10%, by weight, chlordane applied at the rate of 10 lbs. per acre to be 

 about as effective as calcium arsenate applied at the rate of 6 lbs. per acre in 

 controlling the boll weevil. Benzene hexachloride dust containing 5%, by weight, 

 gamma isomer applied at the rate of 10 lbs. per acre was somewhat more effec- 

 tive than the chlordane or calcium arsenate dusts. 



Effectiveness of the control with insecticides decreased as an overlapping of 

 weevil generations resulted in a daily reestablishment or increase of the popula- 

 tion. Final yields showed about the same gain in a field where calcium arsenate 

 was applied 1 week after appearance of the first squares and each week there- 

 after for a total of 3 applications as in a field where 5 dustings were made 

 throughout the season with each application delayed until after 25% or more of 

 the squares had become infested, despite the fact that the latter field had the 

 lowest infestations. 



Laboratory experiments demonstrated that susceptibility of the boll weevil 

 to benzene hexachloride increased as temperature was increased. This was true 

 to a lesser extent for chlordane. Dust containing 4% gamma isomer was more 

 toxic than dust containing 4% chlordane concentrate. 



1947 - Ewing, K. P., C. R. Parencia, Jr., and E. E. Ivy. Cotton-insect control with 

 benzene hexachloride, alone or in mixture with DDT. J. Econ. Ent. 40(3):374- 

 381. 



In field-plot experiments at Waco, Tex., during 1946 benzene hexachloride 

 dust containing at least 5% of the gamma isomer satisfactorily controlled the boll 

 weevil, Anthonomus grandis Boh., the cotton aphid, Aphis gossypii Glov. , and the 

 cotton leafworm, Alabama argillacea (Hbn.), but produced no control of the boll- 

 worm, Heliothis armigera (Hbn.). Mixtures of 5% DDT and benzene hexachloride 

 containing from 2.88 to 4.31% of the gamma isomer were effective in controlling 

 the boll weevil. These mixtures in several late -season experiments adequately 

 controlled heavy infestations of the boll weevil. 



In one small-plot experiment a mixture of 5% DDT and benzene hexachloride, 

 containing 4.31% of the gamma isomer, produced 1284 lbs. of seed cotton per 

 acre, as compared with 678 lbs. from 5% DDT alone and 144 lbs. from the un- 

 treated check. In a large-scale experiment, begun when the bollworm infestation 

 first developed, a plot treated with a mixture of 5% DDT and benzene hexachloride 

 containing 2.88% of the gamma isomer produced a gain, over the check, of 1114 

 lbs. The gain from the mixture was almost twice as much as from calcium ar- 

 senate at approximately 16 lbs. per acre, and calcium arsenate at 16 lbs. pro- 

 duced a gain of more than twice as much as calcium arsenate at 8 lbs. 



40 



