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tality was 2-4 times greater than the control after 15-24 hr of anesthetization; 

 30-48 hrs without oxygen killed 3-5 times the number held in the control. Boll 

 weevils anesthized with nitrogen and held at 10°C for 24 hr did not die at any 

 higher rate than the control for che first week posttreatment. 



355. ; Dawson, J. R. ; and Borkovec, A. B. 1976. Effects of chemosterilant 

 fumigation on the mortality and sterility of boll weevils. U.S. Agric. 

 Res. Serv. [Rep.], ARS-S-132, 6 pp. 

 Laboratory experiments, using a simpL- closed-flask method and some highly 

 active chemoster Hants, were conducted to determine the effectiveness of fumi- 

 gation as a method of sterilizing the boll weevil, Anthonomus grandis Boheman. 

 After fumigation, males and females were separated, mated with normal, un- 

 treated boll weevils, and fed fresh diet pellets. A maximum 50 eggs were 

 collected each week for 3 weeks after treatment. Half the eggs were checked 

 daily for hatch, and half were implanted and observed 21 days for adult emer- 

 gence. Funigation was generally an effective sterilizing technique. The 

 alkylating fumigants tepa, thiotepa, metepa, and P,P-bis (l-aziridinyl)-N- 

 methylphosphionothioic amide (ENT-61585) were effective in sterilizing 92 to 

 100 percent of treated males for 3 weeks, and fecundity of treated females 

 was reduced to 88 to 100 percent. Tepa, thiotepa, and ENT-61585 were the most 

 active compounds tested at 30** C and required only half the time of metepa or 

 P,P-bis (l-aziridinyl)-N-methylphosphinic amide (ENT-51254) to sterilize boll 

 weevils. The non-alkylating fumigants henipa and hexamethylphosphorothioic 

 triamide (ENT-50918) were effective in reducing egg hatch, but recovery of 

 fertility occurred 3 weeks after hempa treatment. None of the mixtures of 

 the fumigant compounds was more effective as a sterilant than the individual 

 compounds. 



