瓢虫对杀虫剂的敏感性研究

STUDIES ON INSECTICIDE SUSCEPTIBILITY OF LADY BIRDS

用4种不同类别杀虫剂对3种不同用药水平地区的七星瓢虫CoccinellaseptempunctataLinnaeus、龟纹瓢虫Propyleajaponica（Thunberg）的毒力进行了测定，同一种用药水平地区的瓢虫对不同药剂的敏感性差异均极显著，三氟氯氰菊酯＞灭多威＞甲胺磷＞硫丹；三氟氯氰菊酯对用药水平较高地区的七星瓢虫幼虫、成虫的毒力分别为硫丹的8547和617倍。同种药剂对不同用药水平地区的七星瓢虫的毒力差异不显著，而用药水平较高地区的龟纹瓢虫较用药水平较低地区的龟纹瓢虫对三氟氯氰菊酯产生了30．6倍的抗药性，这与核酸酯酶活性提高有关。不同种类杀虫剂对七星瓢虫和抗性棉蚜AphisgossypiiGlover的选择指数差异极为显著，硫丹＞灭多威＞甲胺磷＞三氟氯氰菊酯，如硫丹为4．9，而三氟氯氰菊酯却仅为7．3×10－6。硫丹是防治抗性棉蚜值得重视的一种杀虫剂。

Susceptibility to four kinds of insecticides of Coccinella septempunctata Linnaeus and Propylea japonica (Thunberg) collected from regions where insecticides application levels were different was assayed. Differences of susceptibility of lady birds collected from the same region to different insecticides were remarkable. The order of toxicities was: cyhalothrin > methomyl > methamidophos > endosulfan. Toxicity of cyhalothrin to larvae of C. septempunctata was 8560 times higher than that of endosulfan and to adult was 617 times higher. Differences of susceptibility of C. septempunctata to the same insecticide among populations from different regions were not obvious. But P.japonica collected from Xiajin county where application level of insecticides was high showed 30. 6 times more resistant to cyhalothrin when compared with the population from Laiwu where the application level of insecticides was low. The selective toxicity of different insecticides to C. septempunctata and resistant Aphis gossypii differed greatly.The order of selective toxicities was: endosulfan > methomyl > methamidophos > cyhalothrin. The selective toxicity index of endosulfan was 4. 9 where as the selective toxicity index of cyhalothrin was only 7. 3 ×10-6. Endosulfan is recommended to control the resistant A. gossypii.