Abstract: The resistance ratios (RR) of Plutella xylostella in Wuhan were 197.47-and 100.29-folds to fenvalerate and phosemet compared with a susceptible ( S) strain. The RR declined when the Wuhan field strain ( WH) was reared on fresh cabbage leaves in the laboratory.There was no resistance in WH strain after 20 generation because of complete resistance reversion.The susceptibility of both WH and S strain to methomyl was low and the resistance reversion was also slow. The application of this study in insecticide re...

摘要： 武汉地区小菜蛾田间自然抗性种群（ＷＨ）与室内美国敏感品系（ＡＳ）相比，对氰戊菊酯、亚胺硫磷的抗性倍数分别是１９７．４７倍和１００．２９倍，属高抗水平。将ＷＨ种群在室内无毒条件下饲养测定，其抗性水平逐代下降，至２０代后，抗药性基本消失，敏感性得到恢复，且表现稳定。ＷＨ种群与ＡＳ品系对灭多威的敏感性不高，但其抗药性消失较为缓慢。本研究为害虫抗性治理对策中暂停使用某些药剂的技术措施提供了科学依据。

关键词: 小菜蛾, 抗药性, 消失动态