印楝素乳油对小菜蛾种群的控制作用

通过室内外系统试验探讨了印楝素乳油对小菜蛾Plutella xylostella种群的控制作用。结果表明，其控制作用主要表现在对成虫产卵的显忌避作用。对幼虫的拒食作用以及对生长发育的影响和减少幼虫危害为等方面，印楝素乳油0.005mL/59.0%，使小菜蛾种群趋势指数（I值）降为2.4干扰作用控制指数（IIPC）为0.1079，采用状态空间分析法就印楝素乳油施用后小菜蛾种群数量动态的模拟分析亦表明，其显的控制作用表现在种群发展初期对成虫的忌避作用。

Effects of azadirachtin against the diamondback moth, Plutella xylostella

Effects of azadirachtin dosages on population dynamics of the diamondback moth (DBM), Plutella xylostella, were investigated in both laboratory and field. The results showed that azadirachtin strongly deterred the adult from laying eggs and significantly inhibited larval feeding on the plant with it. When 0.005 mL/L of azadirachtin was applied, 78.3% of the adults of DBM was kept away from the host plant and larval antifeedant ranged from 62.9% to 71.8%. Total food intake by DBM larva decreased to 59.0% of that in the control. The index of population trend of DBM decreased to 2.4 from 22.0 in the control. The interference index of population control was 0.1079. Based on the space-state equation of cybernetics, models of DBM population dynamics were set up, which indicated the deterrent activity of azadirachtin to the adult egg-laying played a key role in population control.