Progress of the studies on the pink bollworm,Pectinophora gossypiella (Saunders), resistance to Bt transgenic cotton EVALUATION OF THE EFFICACY OF PYRETHROIDS RESISTANCE MANAGEMENT IN COTTON BOLLWORM IN HEBEI PROVINCE Advance on the study of pest resistance to chloronicotinyl insecticides Cross-resistance of Cry1Ac-selected Asian corn borer to other Bt toxins The mechanism of insect resistance to Bt toxin and the resistance management tactics