中文摘要：

朱砂叶螨（Tetranychus cinnabarinus）具有个体小、繁殖快、代数多、适应性强、为害重等特点,是世界公认的最难防治的有害生物群落（Hazan et al.,1974;何林等,2004）,可危害百余种农作物和果树,并对其产量和品质造成严重的影响（Ho et al.,1997）。长期以来,大量重复使用非专一性化学杀螨剂,使许多螨类已产生抗药性（唐除痴等,1998）,并且对杀螨剂出现了交互抗性（王旭等,1997）,与

英文摘要：

Fraction 8 of the extractants from semen pharbitidis was identified and its mechanism of biological activity against Tetranychus cinnabarinus was investigated. The main component of the extractant fraction 8 was detected with nuclear magnetic resonance （NMR）, gas chromatography and mass spectrum （GC-MS）. Influences of the main component on several enzymes activities such as glutathione-S-transferase （GSTs）, acetylcholine esterase （AChE） and mono-amine oxidase （MAO）, in T. cinnabarinus body were detected by using biochemical method. Results showed that the main component of the extractant fraction 8 was methyl linoleate. The methyl linoleate activated glutathione-S-transferase in T. cinnabarinus body, while it inhibited to various degrees acetylcholine esterase and mono-amine oxidase related to nervous system, and hence caused the death of T. cinnabarinus. Therefore the methyl linoleate has a good prospect developing into new pesticide.