新疆棉铃虫自然敏感种群对常用杀虫剂浸叶法的毒力基线

选用阿拉尔棉铃虫自然敏感种群(AL-S),在详细观察2龄中期幼虫的形态、行为特征及比较其生理学特性对药剂敏感性影响的基础上,用生理特性一致的2龄中期幼虫,测定了10种常用杀虫剂浸叶法的毒力基线。结果表明:①2龄中期幼虫的形态和行为特征为头宽≤体宽,体色不透明肉色,体节明显且行动较敏捷。此时2龄幼虫的时龄约为10～22h,体重1.33±0.27mg;②试虫生理特性差异影响对药剂的敏感性。2龄幼虫不同发育历期的敏感性,以前期最敏感,中、后期较接近;雌蛾不同蛾龄的卵发育的2龄幼虫敏感性,以4日龄蛾卵的幼虫敏感性最低,7日龄蛾卵最敏感,5、6日龄蛾的敏感性相近,且介于上述二者之间。故在测定毒力基线时,为保持试虫生理同质性,宜选用5、6日龄雌蛾卵的2龄中期幼虫为佳。③用2龄中期幼虫,获得10种药剂浸叶法的毒力基线,杀虫剂致死中浓度(LC_(50))按以下次序增大:功夫菊酯、溴氰菊酯、氰戊菊酯、硫丹、甲基E605、辛硫磷、毒死蜱、丙溴磷、久效磷、灭多威。

THE INSECTICIDE TOXICTTY BASELINE DATA BY FOLIAR RESIDUE BIOASSAY METHOD ON A XINJIANG SUSCEPTIBLE POPULATION OF HELICOVERPA ARMIGERA HÜBNER

Experiment has been carried out to enhance the accuracy and feasibility of the foliar residue bioassay method recommended by International Pest Resistance Action Committee. The results showed that the age of both the test larvae and their mother moths influenced obviously on bioassay. As the mother moths aged, the descendant larvae became less and less in tolerance. Based on careful observation and comparison, the 2nd instar larvae hatched from the eggs laid by 5-and 6-day-old moths, aged 10-22 hours and weighted 1.33×0.27 mg were selected and used as test insect. The susceptible baseline data of 10 conventional insecticides were constructed by the method. The LC₅₀ of the insecticides tested was arranged in increasing order as cyhalothrin, deltamethrin, fenvalerate, endosulfan, methyl parathion, phoxim, chlorpyrifos, profenofos, monocrotophos, methomyl. The toxicities were also compared with those tested by topical application method.