41 



tural Research Service, U.S. Department of Agriculture. This initiated the 

 1968 High Plains reproductive-diapause boll weevil control program. Ultra- 

 low-volume malathion and azinphosmethyl (Guthion®) insecticide was applied 

 to control fall populations of the boll weevil, Anthonomus grandis Boheman. 

 When the last insecticide application was completed November 5, treated cotton 

 fields being monitored in Kent County (the most heavily weevil-infested county 

 in the control zone) averaged an estimated 2,360 potential overwintering weevils 

 per acre as compared with 4912 potential overwintering weevils per acre in 

 untreated check, cotton fields in Stonewall County. In January 1969, an esti- 

 mated 2,299 weevils per acre were present in hibernation sites near cotton 

 fields treated in the 1968 program in Dickens and Kent Counties as compared 

 to an estimated 11,374 weevils per acre in sites near untreated cotton fields 

 in Stonewall County. 



72. ; Arnold, D. M. ; and Almand, L. K. 1968. Effects of reproductive- 

 diapause boll weevil insecticidal programs on the abundance of bollworm 

 and tobacco budworms in the Rolling Plains of Texas, 1967. Tex. Agric. 

 Exp. Stii. Prog. Rep. PR-2627, 10 pp. 

 Cotton sprayed in the fall with aerial applications of ultra-low-volume (*ULV) 

 malathion and azinphosmethyl (Guthion®) insecticide supported more bollworms, 

 Heliothis zea (Boddie) , and tobacco budworms, H. virescens (f.), than untreated 

 check fields. Larval populations in Kent County fields treated with malathion 

 were considerably greater than in untreated check fields. But in Dickens County, 

 larval populations in fields treated with malathion. were about equal to those in 

 fields treated with azinphosmethyl. In late September and early and mid-October 

 when Heliothis populations were greater, fields treated with azinphosmethyl and 

 malathion in an experiment in Stonewall County averaged 2,200 or more Heliothis 

 larvae per acre on at least one inspection date. This compared to an estimated 



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