取食不同寄主植物的甜菜夜蛾对药剂敏感性的变化

初步探讨了取食不同寄主植物的甜菜夜蛾对药剂敏感性及其体内酶活性的变化。结果表明：取食不同寄主植物的甜菜夜蛾对灭多威、溴氰菊酯的敏感性变化较大，最大LD50之比分别达17．3和44．9倍，而对辛硫磷的敏感性变化不大，最大LD50之比为1．9倍；取食不同寄主植物的甜菜夜蛾体内谷胱甘肽-S-转移酶的活性差异不显著，而羧酸酯酶活性、多功能氧化酶脱甲基作用差异显著，其中羧酸酯酶的活性变化与对灭多威敏感性的变化相一致。因此，羧酸酯酶可能是寄主植物影响甜菜夜蛾对灭多威敏感性变化的因素之一。

Stuties on insecticide susceptibility of the beet armyworm fed on different host plants

Different host plants were fed to the beet armyworm,Spodotera exigua (Hübner).Susceptibility to insecticides and activities of detoxifying enzymes were measured.Results showed that the maximal susceptibility differences of the beet armyworm reared on host plants to methomyl and deltemathrin were 17.3 and 44.9 times respectively,but to phoxim was only 1.9 times.Studies on activities of detoxifying enzymes indicated that activities of carboxylesterase (CarE),microsomal oxi-dases (O-demethylase) were significantly different between strains fed on different host plants,but glutathione-s-transferases activities were not much different.Activity variations of CarE were in consistent with susceptibility to methomyl.