茶皂素对菜青虫作用方式的初步研究

Preliminary studies on mechanism of action of tea saponin on Pieris rapae (Linnaeus)

为探讨茶皂素对菜青虫的作用方式，测定了茶皂素对菜青虫Pierisrapae（Lin-naeus）5龄幼虫的拒食作用，以及对4龄幼虫的触杀和胃毒作用。结果表明，拒食是茶皂素对菜青虫的主要作用方式，当浓度高于800mg／L时，茶皂素对菜青虫5龄幼虫具有很强的拒食活性。此外，在高浓度（＞20000mg／L）下对4龄幼虫具有触杀作用。

In order to study the mechanism of action of tea saponin on Pieris raPae,antifeedingeffect of tea saponin on P. rapae 5-instar larva was examined,and contact poison and stomach poi-son actions of tea saponin on P. rapae 4-instar larva were also examined. Results showed that an-tifeedant effect was major action of tea saponin on P. rapae. And it also had some contact poisonwhen tea saponin was at high concentrations (> 2OOOOmh/L. ). The antifeeding action of teasaponin on P. rapae 5-instar larva was strengthened when its concentrations were above 8OOmg/L.