【目的】为了明确海南地区小菜蛾Plutella xylostella(L.)对氯虫苯甲酰胺和乙基多杀菌素的抗性现状和抗性发展趋势,为制定有效的化学防治措施及抗性治理策略提供参考。【方法】本文采用叶片浸渍法,测定了海南海口、三亚两个地区小菜蛾田间种群2011—2014年度对2种药剂的抗药性水平。【结果】结果表明:自2011年以来,海口地区小菜蛾种群对氯虫苯甲酰胺的抗性倍数从2011年的0.95倍,突然发展为2012年的303.18倍,2013年下降为61.37倍,2014年又上升为92.41倍,年度间波动较大;三亚地区的抗性倍数由2011年的1.16倍,逐年上升为2012年的44.00倍,2013年的51.22倍和2014年度的120.62倍,年度间抗性持续上升,达到高抗性水平。海口地区小菜蛾对乙基多杀菌素的抗性倍数从2012年的1.19倍,发展为2013年的29.35倍和2014年的30.25倍,达到中等抗性水平;三亚地区的抗性倍数由2012年的4.43倍,逐年上升为2013年的30.48倍和2014年度的54.96倍,年度间抗性持续上升。【结论】海南地区小菜蛾对乙基多杀菌素和氯虫苯甲酰胺均已产生中等水平或高水平的抗药性,抗药性呈现持续上升的趋势。这可能与两个地区的用药环境和用药习惯有关。田间防治时,应减少两种药剂的使用次数,注意轮换其它药剂。
[Objectives] To investigate levels of insecticide resistance in different Plutella xylostella(L.) populations in Hainan Province, and thereby improve both the chemical control of this pest and management of insecticide resistance. [Methods] Samples of P. xylostella populations from the Haikou and Sanya area were collected between 2011 and 2014 and their resistance to chlorantraniliprole and spinetoram assayed using the leaf-dip bioassay method. [Results] The results show that the resistance level of the Haikou population to chlorantraniliprole increased from 0.95 to 303.18 fold during 2011-2012, then fell to 61.37 fold in 2013 and to 92.41 fold in 2014. Resistance levels in the Sanya population tended to increase yearly, with the resistance index increasing from 1.16 in 2011 to 44.00 in 2012, to 51.22 in 2013, and to 120.62 in 2014. The resistance levels of Hainan populations of P. xylostella to spinetoram were moderate, the resistance index of the Haikou population increasing from 1.19 in 2012 to 29.35 in 2013, and to 30.25 in 2014, and that of the Sanya population increasing from 4.43 in 2012, to 30.48 in 2013, then to 54.96 in 2014. [Conclusion] Resistance levels of Hainan populations of P. xylostella to spinetoram and chlorantraniliprole generally tended to increase over time, eventually becoming moderate, or high. Differences in resistance levels between P. xylostella populations in Hainan may be attributed to differences in the environment and local methods of insecticide use. The application of both insecticides should be reduced and more emphasis should be placed on using them in rotation with other insecticides.