The dusts were applied at about 11 pounds per acre-application, and the 

 sprays, at approximately 9 gallons. 



The dusts and sprays were applied with 4-row horse-drawn equipment 

 powered by 1 .5-horsepower motors mounted on a platform about 42 inches above 

 the ground. Approximately the same amount of active ingredients was applied 

 per acre in both the dust and spray for each formulation tested. 



Both the dusts and sprays of all formulations gave good boll weevil control 

 and good increases in yield of seed cotton. Dieldrin, in both the dust and spray, 

 was the most outstanding material tested. 



Based on an average of 3 large field tests, the plots sprayed with chlordane 

 plus DDT, toxaphene plus DDT, and toxaphene produced slightly higher yields than 

 the dusted plots. With benzene hexachloride plus DDT, however, the dusted plots 

 outyielded the sprayed plots. 



For boll weevil control there was no advantage in adding DDT to toxaphene, 

 either as a dust or as a spray. 



None of the various dust or spray formulations used in these experiments 

 caused any commercial injury to the cotton plant. 



From the standpoint of boll weevil control, cost of materials and equipment, 

 and the possibility of making spray applications in conjunction with tractor cul- 

 tivation, low-gallonage spraying shows excellent promise. 



1952 - Gaines, J. C, and W. J. Mistric, Jr. Effect of environmental factors on the 

 toxicity of certain insecticides. J. Econ. Ent. 45(3):409-4l6. 



Results of field cage tests indicated that overwintered weevils were more 

 susceptible to toxaphene spray than weevils reared from squares during the 

 early fruiting season. Apparently the depletion of food in the overwintered weevil 

 affected their susceptibility to toxaphene. 



Also, about 4 times as much toxaphene was required to kill weevils reared 

 from bolls as from squares. These data indicated that the type of food upon which 

 the weevils develop affects their susceptibility to toxaphene. 



The results of all the weevil tests indicate that it required 4 or more times 

 as much toxicant of the various materials to effect comparable kill in the field as 

 in the laboratory. Such factors as high temperatures, sunshine, wide ranges in 

 relative humidity, dew, or a combination of these factors greatly reduced the 

 toxicity of the insecticides tested. Toxaphene, TM-1, dieldrin and EPN retained 

 their toxicity for weevils under these environmental conditions better than the 

 other materials tested. The toxicity of parathion, TM-4049, TM-711, BHC-DDT, 

 TM-269, and aldrin was greatly reduced by the environmental factors listed 

 above. 



It was found that it required higher dosages of the insecticides to effect 

 control of weevils late in the season than early in the season. Factors other than 

 environmental effected the toxicity of organic insecticides to boll weevils. Here 

 again, the food upon which the weevils develop may be partially responsible for 

 this resistance to insecticides late in the season. 



Toxaphene and TM-1, a chlorinated terpene, were equally effective against 

 the boll weevil and leafworm. 



1952 - Hanna, R. L., and J. C. Gaines. Evaluation of dusting schedules for control of 

 cotton insects. J. Econ. Ent. 45(3):549. 



There was no significant difference in the total yield between any two treat- 

 ments or treatment combinations. This was probably due to extremely dry, hot 

 weather and light weevil and bollworm damage. However, a significantly higher 

 percentage of the total yield was harvested during the first picking from those 

 plots which received early treatment. 



1952 - Lincoln, C, and F. Williams. Control of cotton bollworms and boll weevil in 

 1951. Ark. Agr. Expt. Sta. Rpt. Ser. 33, 25 p. Apr. 



Gamma BHC (0.3 lbs./ac), Calcium arsenate (7-10 lbs./ac), toxaphene (2.0 

 lbs./ac), dieldrin (0.15 lbs./ac), aldrin (0.25 lbs./ac), and heptachlor, all were 

 effectively used in boll weevil control. Heptachlor, 0.25 to 0.35 lbs./ac was 

 effective. Spraying was satisfactory. 



58 



