江苏省水稻二化螟的抗药性测定及对甲胺磷的抗性机制

采用3龄幼虫点滴法测定了江苏省水稻二化螟对杀虫单和甲胺磷的抗性水平，并就二化螟对甲胺磷产生抗性的机制进行了研究，结果表明，高淳和徐州二化螟种群对杀虫单已达高抗水平，其它地区也表现为中等抗生，在所测定的6个种群中，苏州种群对甲胺磷处于低抗水平，其它种群为中抗种群，澌知体增效作用表明，氧化胡椒基丁醚（PBO）对甲胺磷有明显的增效作用，磷酸三苯酯（TPP）和顺丁烯酸二乙酸（DEM）的增效作用不明显，对离体解毒酶的研究表明，R种群幼虫多功能氧化酶（MFO）的O-脱甲基作用的活力比S幼虫高，R幼虫乙酰胆碱酯酶（AChE)的活力与S幼虫无显著差异。以甲胺磷为抑制剂的R幼虫I50是S幼虫的2.52倍，二化螟对甲胺磷的抗性机理可能与MFO的O-脱甲基作用活力增矿山和AChE的敏感性降低有关。

RESISTANCE MEASUREMENT OF CHILO SUPPRESSAIJS FROM JIANGSU PROVINCE AND ITS RESISTANCE MECHANISM TO METHAMIDOPHOS

The resistance levels of the third instar larvae of Chilo suppressalis colleted from different places of Jiangsu Province, were monitored by means of topical application, and the mechanism of resistance to methamidophos was also investigated. The results showed that Chilo suppressalis from Gaochun and Xuzhou had developed high levels and other populations middle levels of resistance to molosultap. Resistance of six populations to methamidophos, except for Suzhou population, at low level, were all in middle levels. Synergism experiments indicated that PBO had synergism to methamidophos in high-level resistant strain, while, TPP and DEM did not have synergistic effect on the same insecticide. The ratio of 0-demethylation activities of MFO extracts from R strain to that of S strain was found to be 3.70. The activity of AChE in R and S strains was not significantly different , but I50 of methamidophos in R strains is higher than that in S strains. The resistant mechanism of Chilo suppressalis to methamidophos may be associated with the rising of 0-demethylation of MFO and insensitivity of AChE.