1951 - Beckham, C. M., and M. Dupree. Progress report-- summary of cotton insect 

 control experiments during 1951. Ga. Expt. Sta. Mimeo. Series 38. Dec. 



Includes a report on 3 experiments--(l ) a comparison of the effectiveness of 

 several commonly used insecticides applied as emulsifiable concentrates 

 (toxaphene-DDT), (aldrin-DDT), and (dieldrin-DDT); (2) effectiveness of dust 

 formulation (BHC-DDT), (aldrin-DDT), (heptachlor-DDT), (toxaphene), (dieldrin- 

 DDT), and (calcium arsenate); (3) dust formulation comparisons. No conclusions 

 were drawn by the author. 



1951 - Gaines, J. C, H. A. Dean, and Read Wipprecht. Tests of insecticides for control 

 of cotton insects during 1950. J. Econ. Ent. 44(3):367-372. 



In a split-plot, randomized, block experiment, toxaphene, toxaphene-DDT, 

 and gamma benzene hexachloride-DDT dusts proved equally effective for boll 

 weevil and bollworm control. The spray formulation of toxaphene-DDT was 

 as effective as the dusts. Toxaphene and gamma benzene hexachloride-DDT 

 sprays were not so effective as the toxaphene-DDT spray nor the toxaphene dust. 

 In laboratory tests, toxaphene-DDT spray proved more effective than toxaphene 

 spray for control of the boll weevil, particularly at the high levels of kill. The 

 mixing of toxaphene and DDT did not increase the toxicity of the mixture for 

 control of the weevil over comparable dosages of toxaphene and DDT applied 

 separately. 



In large plots, results were obtained comparable to those of the small 

 replicated plots. Results from the 4 tests with plots ranging in size from 1 to 40 

 acres indicate that sprays applied either with a tractor or an airplane were 

 effective for boll weevil and bollworm control. In the tests, 6 to 12 applications 

 were required, and average net gains in yields over the check plots ranged from 

 672 to 1,223 pounds of seed cotton per acre, a net profit ranging from $75 to 

 $133 per acre. 



1951 - Gaines, J. C, E. E. Ivy, and C. E. King. Toxicity of certain phosphorus com- 

 pounds to cotton insects. J. Econ. Ent. 44(5):750-753. 



The new phosphorus compounds TM-4049, S-( 1 ,2-dicarbethoxyethyl) 

 0,0-dimethyl dithiophosphate; TM-4018, S-(l ,2-dicarbomethoxethyl) 0,0-diethyl 

 dithiophosphate; TM-4124, 0,0-dimethyl 0-2-chlor-4-nitrophenyl thio-phosphate 

 proved less toxic than either tetraethyl pyrophosphate or parathion for spider 

 mite control. TM-4124 was more toxic to mites at the 50% mortality level than 

 either TM-4018 or TM-4049, while the compounds had about the same degree of 

 effectiveness at the high levels of mortality. 



In laboratory tests TM-4124 proved highly toxic to aphids, and in a field 

 test compounds TM-4124 and TM-4049 applied at 0.3 and 0.4 pounds per acre, 

 respectively, gave excellent control. 



Neither of the phosphorus compounds tested proved so toxic to the bollworm 

 as toxaphene. TM-4124 was effective against the boll weevil. A mixture contain- 

 ing 3% of TM-4124 and 15% of toxaphene proved effective against both boll weevils 

 and boll worms. 



1951 - Gaines, J. C., and W. J. Mistric, Jr. Effect of rainfall and other factors on the 

 toxicity of certain insecticides. J. Econ. Ent. 44(4):580-585. 



In laboratory and greenhouse tests, spray formulations of toxaphene, aldrin, 

 and dieldrin proved to be more effective for boll weevil control than did the dust 

 formulations. Considerably higher dosages of these insecticides applied as spray 

 emulsions were necessary to give a kill in the field comparable to that in either 

 the laboratory or greenhouse. Since the temperatures did not vary much in either 

 location, it is assumed that the wider range in percentage relative humidity, sun- 

 shine, dew, and wind or a combination of these factors, brought about a decided 

 reduction in the toxicity of toxaphene, dieldrin, and aldrin. These factors reduced 

 the toxicity of aldrin more than either toxaphene or dieldrin. 



The application of 0.5 inch of simulated rain did not affect the toxicity of 

 toxaphene or dieldrin sprays when used to boll weevil control in the laboratory. 

 The toxicity of aldrin spray was, however, greatly reduced by the simulated rain. 



55 



