327 



tion the least, the constant pattern increased average boll weight the least, 

 and the fluctuating pattern increased the percentage of bolls set the least. 

 Effects of the different patterns of square removal on yield were not signi- 

 ficant, but effects on early date of production and harvest were significant 

 and of practical importance. The fluctuating pattern of square removal delayed 

 total production 10 days and total harvest 15 days. Both production and harvest 

 were delayed an additional 2 weeks by the constant pattern of square removal and 

 3 weeks by the increasing pattern. The fluctuating pattern of square removal 

 more nearly approximates weevil infestations in North Carolina, and it is 

 potentially less detrimental to cotton production than the constant and in- 

 creasing patterns. The effect of boll weevil square infestation on the yield 

 of treated cotton was similar to the effect of square removal on the yield of 

 protected cotton, that is, up to 45% (8-week average) square infestation or 

 removal had no significant effect on yield. At about this level of square in- 

 festation, the yield of untreated cotton was reduced 50-60%, principally 

 because of boll damage and boll abscission caused by weevil attack. Thus, 

 within this level of square infestation, protection of the yield was mostly a 

 matter of protecting bolls. Three treatments schedules are described which - 

 protected the yeild at square-infestation levels, ranging from ^out 10 to 45%. 



633. , and Covington, B. M. 1968. A preventive boll weevil control program 

 applied to a ten-squire-mile area within an untreated county. J. Econ. 

 Entomol. 61: 186-190. 

 A preventive control program against the boll weevil, Anthonmus grandis Boheman, 

 was applied to a 10-square-mile area within untreated Roberson County, North 

 Carolina, in 1960. The treatment schedule consisted of 4 early-season insecticide 

 applications beginning at the 8-leaf stage of cotton growth plus late-season appli- 

 cations beginning the last week of July and continuing to the end of squaring. 



