IPM strategy in the Chinese Bt cotton-planting region

Bacillus thuringiensis (Bt) transgenic crops engineered to express special insecticidal toxin proteins for control of the target pest insects, have been commercialized worldwide. China began to plant Bt cotton in 1997, and extended to 3.8 million hectares in 2009, which was equivalent to 68% of the national cotton crop of 5.7 million hectares. Field evaluations and practices indicate that Bt cotton resistance efficiency appears promising to several lepidopteran species. Also, the planting Bt cotton efficiently prevents a resurgence of cotton aphids caused by insecticide use for control of cotton bollworm. However, the mixed populations of mirids increase drastically in due to a reduction in the number of foliar insecticide applications for control of the bollworms in Bt cotton fields, and get into a key problem in cotton production. In consideration of the pest status evolution in Bt cotton, a control strategy of the pests including in chemical control, trap crop, culture control etc, has been developed in China.