Influences of Bacillus thuringiensis Berliner cotton planting on population dynamics of the cotton aphid, Aphis gossypii Glover, in northern China

The influence of Bacillus, thuringiensis Berliner (Bt) cotton on population dynamics of cotton aphid. Aphis Glover. was investigated 1999 21(0) ill northern China. The field experiments were conducted in plot,, of fit cotton and conventional cotton that received no insecticide applications, and in plot, of conventional cotton ill which pyrethroid and organophosphate insecticides were used regularly for control of Helicocerpa armigera The results indicate that resistance of cotton aphids, to majority of insecticides used for control of H armigera. and lower densities of predators ill late June and early July caused by insecticide use causes population densities of cotton aphids to become significantly higher ill plots of insecticide-treated conventional cotton than in Bt cotton plots, These results suggest that Bt cotton planting not only played an important role in the control of H. armigera, but also efficiently prevented cotton aphid resurgence ill response to insecticide use.