取食不同寄主植物的小菜蛾对定虫隆敏感性的变化

取食不同寄主植物的小菜蛾３龄幼虫对定虫隆的敏感性发生了显著的变化。其中，以取食萝卜的小菜蛾３龄幼虫最为敏感，其次是甘蓝、菜心、西洋菜和白菜，取食花椰菜的最不敏感。但用不同寄主植物饲养小菜蛾一个完整的世代，再统一用菜心饲养至３龄，用定虫隆生测的结果是，其敏感性差异不明显。本文还对因不同寄主植物诱导的小菜蛾药剂敏感性变化的实质进行了讨论。

Effect of Food Plants on the Susceptibility of the Diamondback Moth(Lepidoptera: Plutellidae) to Chlorfuazuron

The Larvae of diamondback moth, Plutella xylostella L. , were fed pad-choi Brassica campestris L. ssp. chinensis(L. )Makino var. communis Tsen et Le , flowering Chinese cabbage (B. campestris L. ssp. Chinensis var. utilis Tsen et Lee), cabbage (B. oleracea L. var. capitata L. ), cauliflower (B. oleracea L. var. botrytis L. ), radish (Raphanus sativus L. ), and watercress (Nasturtium officinale R. Br) untill they were sprayed with chlorfluazuron in the third instar. The observed mortalities were analysed by linear correlation regression models, and the LC_(50) calculated. The result of bioassays showed that the larvae of diamondback moth bred from different host plants had remarkable difference in susceptibility to chlorfluazuron. The order of susceptibility to chlorfluazuron was radish>cabbage>flowering Chinese cabbage>watercress>pak-choi>cauliflower. The quality of the variation ininsecticide susceptibility induced by different host plants was also discussed in the paper.