银杏外种皮中银杏酚酸对小菜蛾幼虫的拒食及毒杀作用

小菜蛾(Plutella zylostella L.)是一种全球性的重要害虫，其抗药性引起国际学术界的广泛关注，而开发高效、低毒、低残留、无污染的生物农药成为了国内外农药开发的主流．报道了从废弃的银杏(Ginkgo biloba L.)外种皮中分离到的银杏酚酸对小菜蛾的拒食和毒杀作用．实验采用皂化和酯化反应及柱层析方法从银杏外种皮中分离获得银杏酚酸，并对1～3龄小菜蛾幼虫进行生物测定．生测结果表明银杏酚酸对小菜蛾有较好的拒食和毒杀作用．当处理的质量浓度为6．25mg／L时3龄幼虫的非选择性拒食率在24，48h后分别达到77．8％，94．7％以上．处理时间达到48h时，1～2龄幼虫的LC50为1.31mg／L，3龄幼虫的LC50为6．07mg／L．这表明了银杏外种皮有很好的开发前景，将为今后新型植物农药的开发和银杏废弃物的综合利用提供依据．

Ginkgolic Acids from Ginkgo Exocarp and Their Toxicity to the Diamondback Moth, Plutella xylostella

Diamondback moth( Plutella xylostella ) is an important vegetable pest, whose insecticide resistance attracts much attention of scientists. For this reason, more and more attempts are made to develop biopesticides targeting at the pest. The toxic effects of ginkgolic acids extracted from ginkgo exocarp on P.xylostella were examined. The results show that ginkgolic acids had strong toxicity to 1st-3rd larvae of the diamondback moth. When 6.25 mg/L of acid was applied, non-selective antifeedant of the 3rd instar larvae was 77.8% after 24 h, and 94.7% after 48 h. At 48 h, LC (50) for of 1st and 2nd instar larvae was 1.31 mg/L, and that for the 3rd instar larvae was 6.07 mg/L.On the basis of the above results, it is concluded that the ginkgo exocarps can be used for extracting ginkgolic acids that can be potentially used to develop new biopesticides.