[ Objective ] The purpose of the research was to lay a foundation for applying Agrinwnia pilosa in controlling agricultural pests. [ Method ] The contact toxicities and antifeedant effects of ethanol and acetone extracted fluid and steam distilled fluid from A. pilosa leaves on Myzus persicae were determined by immersion method and leaf soaking method resp. and the determination results were analyzed by uniform design method. [Result] The toxicirv regression equation of 24 h showed that the ethanol extracted fluid and steam distilled fluid had better contact toxicities on M. perskae and the contact toxicity of ethanol extracted fluid was stronger than that of steam distilled fluid. After 48, only ethanol extracted fluid still had better contact toxicity on M. persicae and when the mass concn. of ethanol extracted fluid was 25. 0 mg/ml,its corrected mortality was up to 94. 3% and its value of LC_(50) was 8. 547 0 mg/ml. The toxicity regression equation of 24 h showed that the antifeedant effects of the 3 herb liquors on M. persicae were as follows: steam distilled fluid > ethanol extracted fluid > acetone extracted fluid. After 48 h,only steam distilled fluid still had significant antifeedant effect on M. persicae and its value of AFC_(50) was 10.212 1 mg/ml. [Conclusion] There was substance with significant bioactivity on M. persicae in A. pilosa and it was mainly shown in its contact toxicity and antifeedant effect on M. persicae.%[目的]为将龙牙草用于农业害虫防治奠定基础.[方法]分别采用浸渍法和浸叶法测定了龙牙草叶的乙醇、丙酮浸提液和水蒸汽蒸馏液对桃蚜的触杀和拒食作用,并应用均匀设计法对测定结果进行了分析.[结果]24 h的毒力回归方程表明,乙醇浸提液和水蒸汽蒸馏液对桃蚜有较好的触杀作用且乙醇浸提液的触杀作用大于水蒸汽蒸馏液.48 h后仅乙醇浸提液对桃蚜仍有较好的触杀作用,当乙醇浸提液的质量浓度为25.0 mg/ml时,其校正死亡率达94.3%,LC50=8.547 0 mg/ml.24 h的毒力回归方程表明,3种药液对桃蚜的拒食作用大小为:水蒸汽蒸馏液＞乙醇浸提液＞丙酮浸提液.48 h后仅水蒸汽蒸馏液对桃蚜仍有显著的拒食作用且其AFC50值为10.212 1 mg/ml.[结论]龙牙草中含有对桃蚜具有显著生物活性的物质,主要表现在对桃蚜的触杀和拒食作用.
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