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35 



Anthonomus grand Is Boheman, includes the release of sexually sterile weevils 

 into -.otton fields when population densitities of the pest are low. Therefore, 

 sterilization of this insect is of considerable practical importance and numerous 

 techniques for achieving the goal were explored. One of the oldest and still 

 most promising techniques is chemosterilization and thousands of canaidate com- 

 pounds were evaluated as potential chemosterilants. The principal requirement 

 for a suitable sterilant is a high organ specificity that would cause permanent 

 sterility in both sexes of the weevil and minimal damage to the vigor and longe- 

 vity of the male. At present only certain alkylating agents are known to have 

 such effects and new methods of applying them to laboratory-reared weevils are 

 being developed. The mechanism of action of alkylating sterllants involves 

 direct Interaction between the compound and the reproductive organs or the 

 gametes. However, other types of sterllants that interfere with various re- 

 gulatory processes can also be utilized particularly in combination with 

 alkylating agents. 



61. , and McHaffey, D. G. 1977. Chemosterilization of the boll weevil by 



fumigation. J. Econ. Entomol. 70: 424-426. 

 Fumigation of adult Anthonomu s grand is Boheman at atmospheric pressure with 

 alkylating aziridinyl phosphine sulfides and oxides or with nonalkylating 

 dimethylamino phosphorus amides induces sterility in both sexes. Lowest 

 mortality and complete sterility of both sexes were obtained when the fumi- 

 gant was a mixture of P,P-bis(l-aziridinyl)-N-methylphosphinothioic amide and 

 hempa. The fumigation was performed at SCil^C in a 4-liter stainless steel 

 vessel furnished with a fan driven by an external motor. At an exposure 

 period of 2.5 h, the sterility of males and females was 100 and 99.9%, respectively; 

 mortality of treated weevils was ca. 40% at 8 days posttreatment. The procedure 

 is simple and applicable to mass treatment. 



