辛氰和乐氰混剂对甘蓝桃蚜抗性演化的影响

THE EFFECTS OF MIXTURES OF PHOXIM (OR DIMETHOATE) AND FENVALERATE ON RESISTANT EVOLUTION IN GREEN PEACH APHIDS

用辛硫磷与氰戊菊酯、乐果与氰戊菊酯的最佳配比及其相应单剂对甘蓝桃蚜进行抗性选育,汰选20代时桃蚜对两种混剂的抗性,分别为4.20和2.68倍,比相应单剂的抗性发展速度慢,尤其比氰戊菊酯单剂(289倍)更慢,表明上述两种混剂都可延缓桃蚜的抗性发展。用酶抑制剂进行增效作用测定结果表明:K_1和TPP对辛硫磷和乐果都有增效作用,尤以K_1的增效作用更显著,其增效比分别为1053和38,说明桃蚜对辛硫磷和乐果的抗性与羧酸酯酶有关,尤以敖酸酯酶在辛硫磷的解毒代谢中作用更强。PB对氰戊菊酯和辛硫磷都有增效作用,SV_1对氰戊菊酯增效也较明显,表明桃蚜对氰戊菊酯和辛硫磷的抗性与MFO酶系和酯酶都有关,但对氰戊菊酯的抗性以MFO酶系更重要。

The green peach aphids (Myzus persicae Sul. ) were selected in the green house with phoxim, dimethoate fenvalerate alone and mixtures of the later with each of the former. After twenty times selection,the resistant levels of green peach aphids of the above two mixture (4- 20- and 2- 68-fold) were lower than their individual components, especially fenvalerate (289-fold). The result clearly showed that the above two mixtures of phoxim (or dimethoate) and fenvalerate would delay the resistant development of green peach aphids than each components of mixture. Co-application of the detoxication enzyme inhibitors, such as K1,TPP,PB and SV1 with each of the above three insecticides to its selected colonies in the laboratory. The results showed that phoxim and dimethoate were significantly synergisted by KI and TPP, especially K1. The synergistic ratios were 1058- and 38-fold respectively. It showed that the resistant mechanism of green peach aphids against phoxim and dimethoate was in relative to increase the carboxylesterase activity, especially phoxim, PB and SV1 also could synergisted fenvalerate. It showed that the resistance of green peach aphids to fenvalerate were correlated with the mixed function oxidase (MFO) and esterase, especially MFO.