104 



bollworm ( Hellothis zea Boddie) ; or tobacco budworm (H. virescens Fab.)* Its 

 superior performance may be due to rapid fruiting and a shorter exposure of 

 tender fruiting parts to insect attacks. The prolific nature of Pee Dee 6520 

 may partially compensate for insect injury to fruiting parts, because they are 

 replaced more rapidly in this line than in other cultivars. Seed (25 g) of this 

 breeding stock may be obtained from AR, SEA, USDA, Pee Dee Experiment Station, 

 Florence, SC 29503. 



19A. Curry, G. L.; Sharpe, P. J. H.; DeMichele, D. W. ; and Gate, J. R. 1980. 



Towards a management model of the cotton-boll weevil ecosystem. J. 



Environ. Manage. 11: 187-223. 

 A model of the boll weevil, Anthonomus grandis Boheman (Goleoptera: Gurculionidae) , 

 cotton, Gossypium hirsutum L. (Malvales: I-lalvaceae) , crop ecosystem is presented. 

 Indications are given of its utility in analyzing various control strategies 

 such as pesticide timing, host plant resistance tactics and natural predation and 

 parasitism. The insect component incorporates temperature-dependent development, 

 reproduction and survival, including their stochastic variabilities. The cotton 

 crop model is based on an average plant model consisting of the number of 

 flower buds and bolls in each age category. Bud initiation rates, aging, 

 and natural and photosynthate determined shedding of both buds and bolls 

 are considered. The initiation rates and plant capacities can be varied 

 to mimic plant genotype responses under a variety of soil and climatic con- 

 ditions. The crop-insect interaction components consist of insect searching 

 behavior and preference for egg deposition sites, shedding of infested fruit 

 (buds and young fruit) and fruit drying as it relates to boll weevil larval 

 mortality. The boll weevil-<_otton crop model predicts the yield of both 

 unattacked and infested crops for comparative purposes. Cost comparisons 

 based on the proportional yields facilitate a quantitative analysis of the 



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