为了研究无公害生物农药对小菜蛾的防治效果,采用固-液连续萃取法提取印楝(Azadirachta india A.Juss)种仁的活性物质,减压浓缩后得到粗提物,得率13.8％;应用高效液相色谱测得浸膏中楝素的含量为17 mg/g.室内毒力测定结果表明该提取物对小菜蛾(Plutella xylostella L.)幼虫具有较强的毒杀作用;用不同稀释倍数的种仁甲醇粗提物对小菜蛾幼虫进行了拒食作用的测定,试虫的拒食率分别达到37.5％、47.6％和61.9％.结果表明印楝提取物对小菜蛾幼虫具有较好的防治效果.%The toxieity of the extract from neem tree (Azadiachta Mica 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.
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