三种化学杀虫剂对病原线虫侵染暗黑鳃金龟能力的影响

Evaluation of the Impacts on Infection Ability of Entomopathogens Nematodes to Grub, Holotrichia parallela for Three Chemical Pesticides

昆虫病原线虫作为生物杀虫剂已被广泛应用。为了提高其对蛴螬的防治效果,筛选与昆虫病原线虫适宜混用的化学杀虫剂是一项重要的应用研究。本研究测试了70%吡虫啉水分散粒剂、40%毒死蜱乳油和2.5%高效氯氰菊酯乳油对病原线虫Heterorhabditis bacteriophora Cangzhou strain、Steinernema longicaudumX-7和Heterorhabditis indica LN2存活以及侵染率的影响;筛选出杀虫剂与病原线虫混合对暗黑鳃金龟Holotrichia parallela 2龄幼虫致死效果的最佳配比。结果显示:3种杀虫剂对3种线虫的存活均无亚致死作用;吡虫啉对3种线虫的致死率无明显影响,其中LN2在1/50 RC(含量为9.33μg mL 1)和1/100 RC(4.67μg mL 1)低浓度处理的死亡率显著低于对照;推荐浓度的高效氯氰菊酯(16.67μg mL 1)对3种线虫的致死率均显著高于对照;不同浓度的毒死蜱对3种线虫的致死率存在显著差异。70%吡虫啉1/10推荐浓度(有效成分为46.67μg mL 1)与线虫Hb混用暗黑鳃金龟2龄幼虫死亡率提高了87.51%,与X-7和LN2混用后,致死率分别提高了39.99%和47.37%。其中1/10推荐浓度吡虫啉与线虫Hb混用对暗黑鳃金龟2龄幼虫表现出增效作用,其它浓度的吡虫啉和另外两种药剂与3种线虫混用的各处理均表现为相加作用。

Entomopathogenic nematodes have been applied as a kind of biological pesticides in pest control.To escalate their control effect on Grubs,screening pesticides as synergists for entomopathogenic nematodes is an important application research.In this paper,we tested the infectivity and the survival rates of three entomopathogenic nematodes（Heterorhabditis bacteriophora Cangzhou strain,Steinernema longicaudum X-7 and Heterorhabditis indica LN2） after dipping in three kinds of commonly used pesticides（70% imidacloprid wettable granule agent,40% chlorpyrifos emulsifying concentrate and 2.5% beta-cypermethrin emulsifying concentrate）.The mortality of the 2nd-instar larvae of Holotrichia parallela treated with different combinations of the nematodes and chemical pesticides were determined,and the best combination was screened out.Results showed that each of the three kinds of pesticides had no sub-lethal reaction to any of entomopathogenic nematodes and imidacloprid had no significant effect to the three nematodes.Lethality of imidacloprid to LN2 at low concentration treatments of 1/50 RC（9.33 μg mL 1） and 1/100 RC（4.67 μg mL 1） was significantly lower than that of the control.Lethality of beta-cypermethrin emulsifying with recommended concentrate to three nematodes at the recommended concentration（16.67 μg mL 1） was significantly higher than that of the control,and the mortality of three nematodes treated with different concentrations of chlorpyrifos emulsifying concentrate were significantly different.70% imidacloprid（46.67 μg mL 1effective components） with Hb improved the lethality to the 2nd-instar larvae of H.parallela by 87.51%;when combined with X-7 and LN2,the lethality could be improved by 39.99% and 47.37%,respectively.Synergistic interaction was observed on the lethality to the 2nd-instar larvae of H.parallela by the combination of imidacloprid at 1/10 recommended concentration and Hb.Other combinations only resulted in additive mortality.