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316 



periods of light and darkness on diapause were also determined. 



614. Matin, A. S. M. A.; Wright, J. E.; and Davich, T. B. 1980. Effect of 

 low levels of gamma irradiation on longevity and sterility of the boll 

 weevil. Southwest. Entomol. 5: 112-117. 



Dose-effect studies with a laboratory strain of Anthonomus grandis Boheman were 

 conducted with gamma radiation from 2 sources delivered at 2 dose rates. The 

 6-day-old weevils were less sensitive than the 2- or 3-day-old weevils to the 

 effects of radiation on oviposition. The 2 dose rates of 356 rad/min and 120 

 rad/min from Co and Cs, respectively, were equal in biological effects. 



615. Mauldin, J. K. ; Hamner, A. L.; and Brazzel, J. R. 1966. The effect of 

 insecticides on egg production of the boll weevil, Anthonomus grandis 

 Boh. J. Ga. Entomol. Soc. 1: 15-19. 



Periodic treatment of five generations of boll weevils with a toxaphene-DDT 

 mixture caused a decrease in susceptibility for three generations and a sub- 

 sequent leveling off. Egg production decreased gradually through the five 

 generations of selection. Similar treatment with methyl parathion also caused 

 a decrease in egg production, but susceptibility decreased very little through 

 tw*5^ene fat ions oi selection. Along with reducing egg production the toxaphene- 

 DDT mixture appeared to eliminate those insects with a high reproductive poten- 

 tial. It would appear that the insecticides used in boll weevil control act 

 not only as lethal agents, but also as reproduction inhibitors. 



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