茶皂素对菜青虫的拒食作用方式及机制

采用注射、熏蒸、点滴、饲喂、内吸等方法测定了茶皂素对菜粉蝶Ｐｉｅｒｉｓ　ｒａｐａｅ　Ｌ．５龄幼虫的拒食活性。结果表明，茶皂素对５龄菜青虫具有很强的饲喂拒食活性，２４小时选择性拒食中浓度ＡＦＣ_(５０)为４０．８８ｍｇ／Ｌ，非选择性拒食中浓度为３２１．９２ｍｇ／Ｌ；并具有一定的内吸拒食作用，尤其是根部施药法内吸拒食活性较明显。茶皂素对菜青虫无显著的注射、熏蒸、点滴拒食作用。

Studies on modes and mechanisms of antifeeding action of tea saponin against imported cabbage worm Pieris rapae L.

The antifeeding activity of tea saponin against the 5th instar larvae of Pieris rapae were determined by the methods of injection, topical application, fumigation, systemic action and feeding, etc. Tea saponin showed strong antifeed- ing activity when imported cabbage worms were fed on leaves treated with tea saponin. The choice and no-choice media antifeeding concentrations in the 24 hours after treatment were 40. 88mg/L and 321. 92mg/L, respectively. Tea saponin al- so showed some systemic antifeeding action to imported cabbage worm, espcially with the method of giving drug to the ro- ot of young chinese kale. But tea saponin had no obvious antifeedant effects when the methods of injechon, fumigation and topical application were adorted.