for control of cotton insects have been available to farmers for about one year. At 

 the present time the cost of spraying, as compared with dusting, is about the same. 

 Spraying should be done from about 9 a.m. to 7 p.m., when the wind velocity is not 

 more than 10 to 15 miles per hour. 



Dusting should be done at night between 7 p.m. and 8 a.m. Usually the wind 

 currents are too strong during the day to permit effective control for dusting. 



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

 new organic insecticides. S.C. Agr. Expt. Sta. Rpt. 62:71. Dec. Clemson. 

 Three new insecticides were tested during 1949: aldrin, dieldrin, and 

 heptachlor. All these poisons gave good boll weevil control when used as dusts 

 at 10 pounds per acre, with application at the following strengths: aldrin, 2.5 

 percent; dieldrin, 1.5 percent; and heptachlor, 5 percent. 



1950 - Bondy, Floyd F., L. C. Fife, R. L. Walker, Jr., and C. E. Jernigan. Best time to 

 poison. S.C. Agr. Expt. Sta. Rpt. 62:71-72. Dec. Clemson. 



Where only 3 poison applications were made, best results were obtained if 

 dusting was begun at squaring time or 7 days after squaring and continued at 7- 

 day intervals until completed. When 5 or more applications were made, best 

 results were obtained by making 3 applications at 7-day intervals beginning at 

 squaring and continuing with additional applications at 5 -day intervals when the 

 infestation reached 10% and for as long as it remained above 10% or until the 

 crop was mature. 



Three earlier applications beginning at squaring or 7 days after squaring 

 gave higher increases in yield per application than 5 to 7 applications throughout 

 the season. However, 5 or more applications for the entire season produced the 

 highest yields and the most profitable gains. 



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

 of poison applications. S.C. Agr. Expt. Sta. Rpt. 62:72. Dec. Clemson. 



To determine how often poison should be applied, 3 tests were conducted 

 over a 2-year period. For midseason or late season poisoning these tests showed 

 that after 5 -day intervals of application, the average yield was 145 pounds of 

 seed cotton per acre more than after 7-day intervals, regardless of the type of 

 poison used. 



If dusts are applied after blooming begins, they should be applied at 5 -day 

 intervals so long as the square infestation remains above 10% or until the crop 

 is mature. However, if rain falls within 24 hours after dusting, the application 

 should be repeated within 48 hours. 



1950 - Calhoun, S. L., and W. R. Smith. Control of boll weevil, bollworm, and cotton 

 aphid with organic insecticides applied as concentrated sprays. J. Econ. Ent. 

 43(5):606-6l0. 



Several of the organic insecticides (chlorinated camphene, chlordane, DDT, 

 BHC, and tetraethyl pyrophosphate), applied by airplane as concentrated sprays, 

 at the same rate of toxicant per acre as recommended in dust form for boll 

 weevil, bollworm, or cotton aphid control, gave moderate to excellent control of 

 these insects in preliminary late season, large-scale tests at Belzoni and Rolling 

 Fork, Miss. 



The organic insecticides applied as sprays with ground equipment at Stone - 

 ville, Miss., failed to give any appreciable boll weevil control. Dilution of the 

 insecticides, rain, extended intervals of application, and small plot size may have 

 been factors contributing to the failure. 



1950 - Dean, H. A., and J. C. Gaines. Comparison of dusts and sprays for cotton insect 

 control. J. Econ. Ent. 43(2):225-226. 



Under conditions of heavy boll weevil migration and moderate bollworm in- 

 festation, 3% gamma benzene hexachloride-5% DDT spray produced much poorer 

 control of these insects and a significantly lower yield than toxaphene dust. The 

 yield with toxaphene -DDT spray was significantly higher than toxaphene spray 

 but equal to that of 20% toxaphene dust. All 3 sprays failed to control the boll 

 weevil as well as did 20% toxaphene dust under this heavy weevil migration. 



49 



