亚致死剂量杀虫剂对异色瓢虫繁殖力的影响

为协调害虫的化学防治与生物防治，测定了吡虫啉、鱼藤酮、氰戊菊酯、阿维菌素、抗蚜威和印楝素6种杀虫剂亚致死剂量对异色瓢虫成虫繁殖力的影响．结果表明，各处理异色瓢虫每雌每日产卵量为40～55粒，吡虫啉接触法和饲喂法预处理及鱼藤酮和印楝素饲喂预处理后，均显著低于对照．所有处理间每雌累积产卵量差异不显著．6种药剂2种方式处理异色瓢虫后，其所产卵的孵化率均低于对照，从卵发育至蛹期的累积存活率均显著降低．吡虫啉两种方式处理和氰戊菊酯接触处理，从卵至蛹期的总发育历期显著延长，鱼藤酮两种方式处理和氰戊菊酯、阿维菌素、抗蚜威、印楝素饲喂法处理的总发育历期明显比对照缩短，而鱼藤酮和阿维菌素接触处理的与对照差异不显著．药剂直接浸渍处理异色瓢虫卵后，各处理卵的孵化率均较对照降低．氰戊菊酯处理的l龄幼虫存活率也明显较对照低，2龄至蛹期的存活率也有所下降．鱼藤酮和氰戊菊酯处理的总发育历期显著延长．这些研究结果显示，低剂量的杀虫剂对异色瓢虫繁殖力的影响很复杂，药剂的类型、作用方式、毒性高低以及给药途径等均影响到试验结果．

Sublethal effects of insecticides on fecundity of multicolored Asian ladybird Harmonia axyridis

The effects of sublethal doses of 6 insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on the fecundity of multicolored Asian ladybird Harmonia axyridis were determined respectively. The results showed that in all treatments, the daily average number of eggs per female ladybird was about 40-55. Ladybirds pretreated with imidacloprid by contact and feeding methods, and with rotenone by feeding method produced significantly fewer eggs, compared with control. But the accumulative oviposition of ladybirds pretreated with 6 insecticides at sublethal level was no significant differences, compared with untreated ladybirds. The hatching rates of the eggs laid by ladybirds pretreated with 6 insecticides by two methods were all lower than that of control. The accumulative survivals from egg to pupal stage of all treatments decreased significantly. The developmental duration from egg to pupa of those treated with imidacloprid by two methods and with fenvalerate by contact method prolonged significantly, while that of those treated with rotenone by two methods and with fenvalerate, abamectin, pirimicarb, and azadirachtin by feeding method shortened obviously, but that of those treated with rotenone and abamectin by contact method had no differences with control. After the eggs were immersed with sublethal concentrations of imidacloprid, rotenone, fenvalerate and abamectin, the successful hatching rates were all lower than that of control, and the development periods prolonged clearly. The 1st instar larval survival rates of those treated with fenvalerate decreased significantly, and the survivals from 2nd instar larval to pupal stage also reduced to some extent. The total developmental duration of those treated with rotenone and fenvalerate prolonged significantly. These findings suggested that the effects of insecticides at low doses on the fecundity of ladybird were very complicated. The class, action mode, toxicity and exposure route of insecticides could affect the results of experiments.