南京郊区小菜蛾抗性测定和几种杀虫剂触杀毒力的比较

Resistance level of diamondback moth from Nanjing and contact toxicity of newly introduced insecticides

研究了南京郊区小菜蛾对拟除虫菊酯类杀虫剂 (溴氰菊酯和氯氰菊酯 )和有机磷杀虫剂 (敌敌畏 )的抗性水平及对有机磷 (甲基毒死蜱 )、沙蚕毒素类 (杀虫单、巴丹 )、氯化烟碱类 (吡虫清 )、苯并吡唑类 (氟虫清 )和阿维菌素(avermectin)等 6种杀虫剂的敏感性水平。抗性测定结果表明 ,与敏感品系相比 ,南京郊区小菜蛾对氯氰菊酯和溴氰菊酯产生了极高的抗性 ,抗性指数分别为 81 41倍和大于 134 15倍 ,对敌敌畏则产生了中等的抗性 ,抗性指数为 10 0 6倍。活体增效试验显示 ,酯酶抑制剂TPP对氯氰菊酯和溴氰菊酯的增效作用分别为 1 46和 1,多功能氧化酶抑制剂PB对氯氰菊酯和溴氰菊酯的增效作用分别为 3 0 2和 1,表明神经敏感性下降可能是小菜蛾对拟除虫菊酯类杀虫剂产生高抗性的主要机制。点滴法测定结果表明阿维菌素、氟虫清、巴丹和杀虫单对抗性小菜蛾的触杀毒力较高 ,LD50 分别为 0 0 0 3,0 0 0 5 ,0 12 2和 0 190 μg/头。这 4种杀虫剂可作为今后防治抗性小菜蛾的替换药剂。

The resistance level of the diamondback moth(DBM), Plutella xylostella (L.),from Nanjing to deltamethrin,cypermethrin and dichlorvos,and the sensitivity to five groups of insecticides were investigated.The bioassay with topical applications showed that the Nanjing strain had developed high resistance to deltamethrin(>134 15 fold)and cypermethrin(81 41 fold),and moderate resistance to dichlorvos(10 06 fold).By means of special synergist tests,it was founded that both TPP,an inhibitor of esterases,and PB,a MFO inhibitor,exhibited little synergism to deltamethrin and cypermethrin,so nerve insensitivity might be the principal mechanism of pyrethroid resistance in DBM. The contact toxicity test indicated that four insecticides,avermectin,fipronil,cartap and monosul,were highly toxic to this strain,with their LD 50 values being 0 003,0 005,0 122 and 0 190 μg/larva,respectively.Furthermore,resistance management strategies for synthetic pyrethroid resistant DBM are also discussed.