

372 



729. Parker, R. D.; Walker, J. K.; Niles, G. A.; and Mulkey, J. R. 1978. The 

 Short-season effect in cotton and escape from the boll weevil. Tex. 

 Agric. Exp. Stn. Bull. B-1315, A5 pp. 



Experiments were conducted in Texas from 1975 through 1976 to investigate the 

 place and value of rapid-fruiting cottons in production schemes directed at 

 minimizing damage from the boll weevil, Anthonomus grandis Boheman. Narrow-row 

 planting and the selection of certain genotypes produced more cotton bolls 

 earlier in the season and increased yields. The benefits of genotype selec- 

 tion depended on the length of time during the bloom and boll set period that 

 injurious numbers of weevils were delayed. Short-season types were more pro- 

 ductive than their long-season counterparts in cases where the weevil-free 

 period was shorter; however, where weevils were delayed the slower-fruiting 

 cottons produced equally well. Susceptibility to boll-lock injury increased 

 daily as bolls developed from later flowers following initiation of blooming. 

 Seventy percent or more of the lint harvested (500-750 pounds of lint per acre) 

 was produced from flowers of the first 3 weeks of blooming. It is during this 

 critical time period that significant boll weevil damage to squares must be 

 prevented if a satisfactory yield (500-^50 pounds of lint per acre) is to be 

 *"*'^obrained without initiation of costly late-season insecticide applications. 



730. Parrott, W. L.; Jenkins, J. N.; and Buford, W. T. 1970. Instars and 

 duration of stadia of boll weevil larvae. Ann. Entomol. Soc . Am. 

 63: 1265-1267. 



Measurement of the head capsules of larval Anthonomus grandis Boheman (Coleop- 

 tera: Curculionidae) demonstrated that the insect has 3 well-defined instars. 

 The mean widths of the head capsule for thelst, 2nd, and 3rd instars were O.Al, 

 0.62, and 0.99 mm, respectively. When eggs were candled, placed in larval diet, 

 and held in an incubator at 29.4°C and 50% RH, 95% of the eggs hatched within 6 



