小菜蛾 (PlutellaxylostellaL .)是十字花科蔬菜上的重要害虫 ,在我国各地都有分布 ,以长江中下游各省受害最重。由于小菜蛾幼虫比较活泼 ,年发生数代 ,特别是该虫对生物杀虫剂Bt和菊酯类农药容易产生抗性等原因 ,导致该虫的防治比较困难。因此筛选防治小菜蛾的药剂是蔬菜生产 Plutella xylostella L., an important pest on cruciferous vegetables, is distributed throughout our country and most affected by the provinces in the middle and lower reaches of the Yangtze River. As the diamondback moth larvae lively, several generations occur, especially the insects Bt insecticide and pyrethroid pesticides prone to resistance and other reasons, leading to more difficult to control the insects. Therefore, screening for the prevention and treatment of diamondback moth medicine is vegetable production