The influence of pesticide applications on Helicoverpa armigera Hübner and sucking pests in transgenic Bt cotton and non-transgenic cotton in China

In 1999 and 2000, bollworm populations on non-transgenic cotton were larger than those on transgenic Bt-cotton. In Bt-cotton fields, the numbers of fourth-generation bollworms were greater than those of in the second and the third generations over all 3 years of study. Leafhopper populations on Bt-cotton were consistently larger than those on non-transgenic cotton during the 3 years of study. Although the use of transgenic Bt-cotton decreased the need for insecticide applications against cotton bollworm, this relaxation from pesticide applications could cause increased populations of sucking insects, which could require additional insecticide applications.