常用杀虫剂对七星瓢虫幼虫的毒力测定

采用点滴法测定了山西晋中地区七星瓢虫幼虫对 7种菊酯类 ,5种有机磷类和其他类型的 3种杀虫剂的敏感性。以LD50 值进行比较 ,七星瓢虫幼虫对菊酯类杀虫剂的敏感性依次为 :高效氯氰菊酯 >氯氟氰菊酯 >溴氰菊酯>甲氰菊酯 >氰戊菊酯 >氯氰菊酯 >氟氯氰菊酯 ,其LD50 值分别为 6 31× 10 -3 、 2 5 7× 10 -2 、 3 10× 10 -2 、 3 77×10 -2 、 1 0 9× 10 -1、 1 32× 10 -1μg/头和 1 71× 10 -1μg/头 ;对有机磷杀虫剂的敏感性依次为 :杀螟松 >氧化乐果 >辛硫磷 >敌敌畏 >马拉松 ,其LD50 值分别为 3 81× 10 -2 、 6 0 6× 10 -2 、 1 5× 10 -1、 2 37× 10 -1和 3 6 8× 10 -1μg/头 ;对其他 3种杀虫剂的LD50 值为 :北农爱福丁 6 70× 10 -3 μg/头 ,吡虫啉 1 2 2× 10 -1μg/头 ,灭多威 1 34× 10 -1μg/头。并与 1991年测定的 4种菊酯类杀虫剂进行了比较 ,其抗性指数分别为 :氯氰菊酯 4 0 9倍 ,溴氰菊酯 3 96倍 ,氰戊菊酯 2倍 ,甲氰菊酯 0 94倍。

The Toxicity of Commonly Used Insecticides to Coccinella septempunctata (Linn) Larva

By topical application method the sensitivities of the field populations of% Coccinella septempunctata%(Linn)larva,collected from Jinzhong region of Shanxi Province,to 7 pyrethroids,5 organophosphates and 3 other insecticides were surveyed. The results showed that compared with LD-{50}values the order of this pest's sensitivity to pyrethroids was beta-cypermethrin>cyhalothrin>deltamethrin>fenpropathrin>fenvalerate>cypermethrin>cyfluthrin,and the LD-{50} values were 6 31×10+{-3},2 57×10+{-2},{3 10×}10+{-2},3 77×10+{-2},1 09×10+{-1},1 32×10+{-1} and 1 71×10+{-1} μg/ larva,respectively. To organophosphates the sensitive order was fenitrothion >omethoate>phoxim>dichlorvos>malathion,and the LD-{50} values were 3 81×10+{-2},6 06×10+{-2},{1 5×}10+{-1},2 37×10+{-1} and 3 68×10+{-1} μg/larva, respectively. The LD-{50} values of the other 3 insecticides abamectin, imidacloprid and methomyl were 6 70×10+{-3},1 34×10+{-1}and 1 22×10+{-1} μg/larva respectively.Taking the results tested in 1991 as relative susceptibility baselines,the resistance retios to cypermethrin, deltamethrin, fenvalerate and fenpropathrin were 4 09, 3 96, 2 and 0 94 fold, respectively.