1950 - Smith, W. R., and S. L. Calhoun. Comparative effectiveness of aldrin applied at 

 different times of the day for boll weevil control. J. Econ. Ent. 43(5):598-60l . 



A large-scale field test was conducted near Stoneville, Miss., in which aldrin 

 was applied 9 times from July 26 to September 3 as an emulsion spray by airplane 

 for control of the boll weevil. Applications were made at 6 and 10 a.m. and at 

 2 and 6 p.m. to determine the influence of climatic factors occurring at different 

 times of the day on toxicity of the insecticide. 



Treatments made at 6 p.m. resulted in significantly better control than those 

 made at 6 a.m. or 2 p.m. but were only slightly better than the one applied at 10 a.m. 

 There was no significant difference in yield between the treated plots. All treat- 

 ments held the infestation sufficiently low to prevent a reduction in yield. The 

 treated plots yielded from 656 to 772 pounds more seed cotton per acre than the 

 untreated check plot. 



Wind movement, temperature, convection currents, and dew were suggested 

 as factors contributing to the differences observed in boll weevil control. 



1950 - Walker, R. L,., Jr., L. C. Fife, and Floyd F. Bondy. Dusting- schedule experi- 

 ments with Toxaphene for boll weevil control. J. Econ. Ent. 43(6):946-947. 



This summary shows good increases in yield from 3 applications of a 20% 

 toxaphene dust, regardless of the schedule used. The gains in pounds of seed 

 cotton per acre per application of insecticide were almost identical for all the 

 schedules when only 3 applications were made. Additional applications always 

 resulted in greater increases in yield per acre, but the increases were not in 

 proportion to those made from the first 3 applications. The data shows an in- 

 crease in yield of approximately 135 pounds of seed cotton per acre for each of 

 the first 3 applications, beginning at time of squaring, 1 week after squaring, or 

 at 10% infestation. For applications in excess of the first 3, the average increase 

 was approximately 50 pounds per acre. 



During the 2 seasons of these tests, boll weevil emergence from hibernation 

 was earlier than normal for this locality. Moreover, weather conditions caused 

 cotton to mature earlier than normal. In years when the weevil emergence is 

 delayed and cotton matures over a longer period, different results might be ex- 

 pected. 



1950 - Young, M. T., and R. C. Gaines. Tests of insecticides to control boll weevil, 

 cotton aphid and two-spotted mite. J. Econ. Ent. 43(5):727-729. 



Experiment 1--A mixture of calcium arsenate plus 2% of nicotine alternated 

 with calcium arsenate alone; a mixture containing sufficient benzene hexachloride 

 to give 3% of the gamma isomer, DDT 5%, and sulfur 40%, when used alone or 

 then alternated with various applications of calcium arsenate; and toxaphene 20% 

 plus sulfur 40% gave good control of the boll weevil. 



Experiment 2--Benzene hexachloride gamma 3% plus sulfur 40% gave good 

 control of the boll weevil. This mixture was much more effective in increasing 

 the yield when 5% of DDT was added. A mixture of calcium arsenate plus 2% of 

 nicotine alternated with calcium arsenate, calcium arsenate alone, and a mixture 

 of benzene hexachloride gamma 3% plus DDT 5% plus sulfur 40%, as needed, 

 against cotton aphids gave good control of the 2 cotton insects and the mite, as 

 well as very satisfactory gains in yield over the check. Chlordane 20% in clay 

 applied at 1 pound per acre per application, and chlordane 10% in pyrophyllite 

 applied at 1.1 pounds were equally effective against boll weevils. However, 

 chlordane was much less effective than most of the other insecticides included 

 in this experiment. 



Experiment 3- -A dust containing 2% of aldrin gave good control of the boll 

 weevil and the cotton aphid, but not of the spider mite. 



Experiment 4--The 2 brands, A and B, of special low-lime calcium arsenate 

 and regular calcium arsenate were equally effective. The special calcium ar- 

 senates plus benzene hexachloride gamma 1% were much more effective in pre- 

 venting an aphid buildup than a similar mixture with regular calcium arsenate. 



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