江西省二化螟抗药性及其防治对策

本试验从1985～1989年,在江西省13个县市、进行了常用药剂对二化螟的毒力测定。结果表明:南昌、新余的二化螟对甲基1605已产生中等程度的抗药性;对甲胺磷产生中等程度抗药的地区是新余。还有八个地区的二化螟对甲基1605,五个地区对杀虫双,二个地区对甲胺磷产生了低度抗药性。此外,南昌地区的二化螟对马拉硫磷与乙酰甲胺磷产生了交互抗药性。但对乐果仍较为敏感。从抗性机制方面的研究表明,抗药性是由二个以上等位基因所控制,酯酶活性增高及乙酰胆碱酯酶抑制率降低是二个较主要的原因。解决和延缓抗药性发展的对策是禁用或限制使用已产生抗药性的药剂。通过复配农药的室内及田间筛选试验,得出甲氯菊酯或嘧啶氧磷加杀虫双是具有延缓抗药性和增效作用的复配杀虫剂。

Studies on Insecticide Resistance of Rice Stem Borer (Chilo Suppressalis Walker) in Jiangxi and Tactics for Control

1. During 1985-1989, insecticide resistance of rice stem borer (Chilo suppressalis walker) to six kinds of insecticides in Jiangxi Province were survied and studied, Methyl -parathion, dimehypo and methamidophos were common insecticides for controlling the borer in the Province, and acephate, malathion and dimethoate were more rarely used. Larvae were collected from thirteen regions of Jiangxi Province and reared in the laboratory, The 5th instar larvae were used as tested insects by the topical application method recommended by FAO(1980). The results showed that: the borers of some regions had developed obvious resistance to some insecticides. The regions where larvae had developed middle resistance to methyl-parathion were Nanchang City and Xinyu City and to methamidophos was Xinyu. The borers of 8 regions to methyl-paratnion and 5 regions to dimehypo and two regions to methamidophos had developed only lower resistant levels, Besides, The borers existed cross - resistance to malathion and acephate in Nanchang City,but they were still sensitive to dimethoate. 2. The results of toxicity tests of fifteen different concentrations of malathion to F2 3 generation of the borers indicated that the development of insecticide resistance was governed by more two sets of alleles. The average activities of mid-gut esterase was 5. 77X 10-5mM/mg Pr. /min. In resistant borer from Nanchang City and 7. 61 X 10-6mm/mg Pr. /min. In the sensitive from Yongxiu County. Acetyl cholinesterase inhibition-ratio of methyl-parathion was 37. 48, for resistant borers but was 84%for sensitive borers. 3. Two synergist insecticide mixtures, methyl-parathion+alphamethrin and dimehypo +oxy - pyrimithate were screened in laboratory and field trials.