几丁质合成抑制剂对小菜蛾的生物活性

几丁质合成抑制剂对小菜蛾户Plutella xylostella L.4龄幼虫毒力测定的结果显示， XRD-473 农梦特、卡死克、抑太保、灭幼脲1号、灭幼脲；号的毒力值(LC₅₀)分别为0.4768、0.8669、1.0754、1.2389、27.0680和36.8591ppm。 国外生产的几丁质合成抑制剂毒力显著高于国产的品种，这类药剂的毒力又明显高于常规药剂敌敌畏、氯氰菊酯、杀虫双等，它们的毒力值(LC₅₀)分别为818.0315、6419.9842、55，.4925ppm。抑太保对小菜蛾幼虫作用方式的研究结果表明，该药剂以胃毒为主，兼有触杀作用。以抑太保、卡死克50ppn的药液饲喂的小菜蛾雌、雄成蛾寿命比单用5%。蜜糖水饲喂的个体缩短1天和4天左右，产卵量减少2/3，卵孵化率显著降低。用抑太保、卡死克50ppm的药液浸渍的小菜蛾卵孵化串分别为5.35%和0。温度对抑太保的毒力有较大影响，在试验温度范围内(10-30℃)，抑太保10ppm处理的小菜蛾种群50%或，75o、95%群体致死时间随着温度上升而缩短。

INSECTICIDAL ACTIVITY OF CHITIN SYNTHESIS INHIBITORSAGAINST DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA

ests of the toxicity of several chitin synthesis inhibitors to the fourth instarlarvae of diamondback moth, Plutella xylostella, were carried out in the laboratory.The results indicated that toxicities of XRD-473, CME-134, Cascade and IKI-7899were markedly higher than those of Dimilin and Alsystin, and toxicities of all thesechitin synthesis inhibitors were significantly higher than those of the conventionalinsecticides DDVP, Cypermethrin and Dimehypo. Stomach poisoning was found to bethe main mode of action, and contact poisoning was also important for IKI-7899 tothe larvae. When adults were fed with the solutions of IKI-7899 or Cascade at 50ppm, life spans of the female and male moths were shortened by 1 and 4 days respectively, number of eggs laid was only about 1/3 that of the untreated moth and therates of egg hatching were reduced to 5.35% and 0, respectively. Temperature showed significant effect on the action of IKI--7899 in the speed of causing larval mortality, and the higher the temperature, the higher the mortality rate within the sameperiod.