Studies on Application of the Extract from Azadirachta indica A. Juss for Control of Plutella xylostella L. Larvae

The toxieity of the extract from neem tree(Azadirachta indica A.Juss) to the diamondback moth(Plutella xylostella L.) was evaluated in laboratory to study the application of the pollution-free biological pesticides.The extracting rate of the methanol extract from neem kernel was 13.8 %,and the azadiraehtin obtained was 17 mg/g by HPLC.In a laboratory study,the methanol extract was effective against the diamondback moth larvae.The antifeedant effect of the diamondback moth larvae on the extract from neem tree was determined.The antifeedant rate of the different concentrations against the diamondback moth larvae were 37.5 %,46.7 % and 61.9 %,respectively,24 h after treated by feeding method.The results showed that the extract from the neem had strong control of the diamondback moth.