Effect of transgenic Bt cotton GK22 on the population dynamics of the insect pests and weeds in Jiangsu cotton region

The effect of transgenic Bt cotton GK22 on the population dynamic of the insect pests and weeds were studied in Nanjing and Yancheng in 2001. Transgenic cotton demonstrated the excellent control of the main insect pests , such as Helicoverpa armigera?Pectinophora gossypiella?Ostrinia nubilalis?Earias cupreoviridis?Anomis flava?Adoxophyes orana, with the decreased number of these pests remarkably .Compare with the non transgenic cotton, the injured squares and bolls by cotton bollworm for GK22 contton were obviously decreased by 87.50%, 90.70%, in Nanjing and by 74.11%, 55.8% in Yancheng, respectively. Whereas, the number of the Adelphocoris suturalis?Aphis gossyppii and Tetranychus cinnabarinus had litter change, and they have becamed the main pests. At the same time, the variety and the number of the weeds in transgenic Bt cotton fields were similar to that in non transgenic Bt cotton fields.