Study on the Efficacy of Azadirachtin EC and Bt Emulsion against Chilo suppressalis in Organic Rice

[Objective] The aim was to explore the biological control technology for Chilo suppressalis in organic rice.[Method] With hybrid rice combination 88S/0293 as tested variety,the control effect of 0.3% Azadirachtin EC and Bt emulsion at different dosages against C.suppressalis in organic rice and the safety were studied.[Result] The application of 0.3% Azadirachtin EC at 2 250 ml/hm2 had more ideal control effect against C.suppressalis in organic rice at the peak of 1st larvae age and its insecticidal effect and seedling protection effect reached 91.6% and 80.0%,resp.The application of 0.3% Azadirachtin EC at 1 500 ml/hm2 also had better control effect and its insecticidal effect and seedling protection effect reached 84.0% and 72.7%,resp.The application of Bt emulsion diluted 500 times also had certain control effect and its insecticidal effect and seedling protection effect were 77.9 and 68.1%,resp.The application of Azadirachtin EC and Bt emulsion not only had no phytotoxicity on rice but also had obvious yield increasing effect,which could be as ideal insecticides for controlling C.suppressalis in the process of organic rice production at present.[Conclusion] The research laid the foundation for the biological control of C.suppressalis in organic rice.