2207 Resistance of Transgenic Bt plus CpTI Cotton to Helicoverpa armigera Hubner and its Effect on other Insects in China

China is the largest cotton-producer in the World with about 4.5 million tons of lint produced annually, which accounts for over 20% of the World’s total production (Xia et al. 2001). Damage from pests is one of the major limiting factors for cotton production in China, among which cotton bollworm (Helicoverpa armigera Hübner) is a key one (Fang et al. 1992). In the early 1990s, due to the dramatic changes in cotton cropping systems, favorable weather condition and rapid development of insecticide resistance, there had been a serious bollworm outbreak in China, resulting in losses of 15-30% cotton lint (Xia, 1993, 1994, 1997). Cultivation of insect-resistant cultivars proves an economical and feasible way for bollworm control.