1953 - Lukefahr, M. J., and J. C. Gaines. Control of immature stages of the boll weevil. 

 J. Econ. Ent. 46(3) :430 -433. 



Six chlorinated hydrocarbon insecticides and 4 phosphorus compounds were 

 tested to determine their effect upon the developing weevils within the squares. 

 In the laboratory experiments the insecticides varied in their toxicity to the de- 

 veloping weevils. In general, the chlorinated hydrocarbons produced a higher 

 percentage of mortality than the phosphorus compounds. A higher percentage of 

 weevils within the treated squares either died in the adult stage or were para- 

 lyzed. 



The insecticides in the hanging square tests gave a marked reduction in 

 control, in comparison with the laboratory tests. This was probably because the 

 leaves prevented the spray from adequately covering the squares. 



When the insecticides were used in the field at recommended dosages for the 

 control of adult boll weevils, there was apparently no mortality or paralysis of the 

 developing forms. 



195 3 - McGarr, R. L. Combinations of insecticides for control of the pink bollworm and 

 other cotton insects in the Lower Rio Grande Valley. J. Econ. Ent. 46(6): 1103- 

 1105. 



Treatments of DDT 1 - 1.5 lbs./ac plus methyl parathion 0.2 - 0.375 lbs./ac 

 and DDT 1-1.5 lbs./ac plus metacide 0.2 - 0.375 lbs./ac applied from 3 to 1 1 

 times were effective against the boll weevil up to time of migration. The addition 

 of dieldrin in the final applications gave good control of this insect. Both mixtures 

 gave substantial reductions in the number of bolls infested and in the number of 

 pink bollworm larvae per infested boll. There was practically no difference in the 

 results between the two mixtures. 



Conditions were suitable for recording yields in only 3 of the tests, since 

 rain washed off 1 application in tests Nos. 1 and 5 and 2 in No. 6. In these tests 

 both mixtures increased the yield to almost twice that in the untreated plots. The 

 gains may be attributed about equally to the control of the pink bollworm and the 

 boll weevil. 



Cotton aphids, bollworms, cotton leafworms, and spider mites were also 

 held in check with the combinations of insecticides. Both methyl parathion and 

 metacide are promising materials, but the former would probably be preferable, 

 since it is a little more effective against the boll weevil. 



1953 - Mistric, W. J., Jr., and J. C. Gaines. Effect of wind and other factors on the 

 toxicity of certain insecticides. J. Econ. Ent. 46(2) :341 -346. 



Results of laboratory and field cage tests for boll weevil control indicate 

 that it required from 2 to 3 times more of the various insecticides to kill com- 

 parable percentages of weevils in the field than in the laboratory. Such climatic 

 factors as high temperatures, wider ranges in relative humidity, sunlight, dew, 

 and wind were important in reducing the toxicity of the various insecticides in the 

 field. When exposed to normal climatic conditions, both in the field and outside of 

 the laboratory, dieldrin retained its toxicity. 



It required from 2 to 3 times as much of the various insecticides to kill 

 comparable percentages of boll weevils late in the season, as compared to early 

 in the season. 



There was no appreciable reduction in the toxicity of toxaphene, EPN, methyl 

 parathion, and endrin to boll weevils following 0.5 inch of simulated rain applied 

 to the plants soon after treatment. The toxicity of heptachlor was reduced appre- 

 ciably by the simulated rain. Aldrin and heptachlor showed a greater reduction in 

 toxicity due to the effects of rain than did any of the other insecticides studied for 

 boll weevil control. These sprays were either washed off the plants or the rain 

 caused a breakdown of the chemical. 



Dew, alone, did not greatly reduce the toxicity of the insecticides. 



When used to control the boll weevil, high temperature (ll6°F.) generally 

 reduced the toxicity of toxaphene, EPN, aldrin, dieldrin, and heptachlor more than 

 did low temperature (68°F.). Aldrin and heptachlor showed greater reduction in 

 toxicity. 



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