483 



bolls by the boll weevil, Anthonomus grandls Boheman, and the bollworm, Helio- 

 thls :zea (Boddie), cotton quality was not affected. 



954. ; Hart, E. R.; Gannaway, J. R^; and Niles, G. A. 1979. Boll weevil and 

 thrlps resistance in pilose cotton. Southwest. Entomol. 4: 132-140. 



Field and cage studies in Texas showed that the "locked square" character of 

 Pilose cotton reduced % of punctured squares from the boll weevil, Anthonomus 

 grandis Boheman, and this translated into greater bloom production. This 

 cotton also expressed resistance to thoips, Frankliniella spp. 



955. , and Niles, G. A. 1971. Population dynamics of the boll weevil and 

 modified cotton types, implications for pest management. Tex. Agric. 

 Exp. Stn. Bull. B-1109, 14 pp. 



The population dynamics of the boll weevil in cotton was investigated near College 

 Station from 1960 to 1963 and from 1965 to 1968. Findings showed that the time of 

 weevil generations in cotton was predictable. Rates of increase of first genera- 

 tion insects from small numbers of overwintered weevils were as great as thirty- 

 fold. When large populations of the overwintered pests infested cotton, a reduc- 

 tion in reproductive efficiency occurred. Rates of increase of twofold to five- 

 fold were recorded. Economic threshold data showed that overwintered populations 

 must be reduced to about 22 females per acre in order not to experience damage 

 from the first generation. Forty or more overwintered females per acre produced 

 ample first generation weevils to inflict heavy damage. When Lankart Sel. 57 

 cotton was used, it was apparent that the major threat of boll weevil damage would 

 result from the first generation. That is, if cotton escaped damage from this 

 generation, the crop would be too mature to experience damage from the second gen- 

 eration, regardless of the size of the second generation. Concepts gained from 

 this study dramatize the importance of early maturing cottons in escaping boll 

 weevil damage and in reducing winter carryover of diapausing individuals. Certain 



