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云杉卷叶蛾(Choristoneura fumiferana(Clemens))是北美地区严重的森林食叶害虫之一。本试验室采用浸叶法测定植物源杀虫剂除虫菊酯对云杉卷叶蛾4龄幼虫的致死剂量,分析幼虫死亡率与致死时间致死浓度之间的相互关系。结果表明,在浓度为12.5、25、50、100和200 μg·L-1时,幼虫LT50(50%害虫死亡的时间)分别为94.78、45.54、20.36、14.39和11.37h,在120 h累积死亡率依次达到50%、67%、93%、100%和100%。4龄幼虫的LC50(50%害虫死亡的浓度)为16.1μg·L-1。因此,除虫菊酯对云杉卷叶蛾幼虫的致死率随着浓度增加而增加,而致死时间随着浓度增加而降低。本实验为除虫菊酯为效防治云杉卷叶蛾提供参考依据。
Choristoneura fumiferana (Clemens) is one of the most serious forest leaf-eating pests in North America. In this laboratory, the lethal dose of botanical insecticides pyrethrins to 4th-instar larvae of Spruce-Turner was determined by dipping leaf method. The correlation between larval mortality and lethal lethal concentration was analyzed. The results showed that at the concentrations of 12.5, 25, 50, 100 and 200 μg · L-1, the larvae LT50 (50% pest death time) were 94.78, 45.54, 20.36, 14.39 and 11.37 h, respectively, The rates reached 50%, 67%, 93%, 100% and 100% sequentially. The LC50 (concentration of 50% pest death) of the 4th instar larvae was 16.1 μg · L -1. As a result, the lethality of pyrethrins to the larvae of Spodoptera frugiperda increased with increasing concentrations and the lethal time decreased with increasing concentrations. The experiment for pyrethrins to provide reference for the prevention and control of Spruce Leafworm.