球孢白僵菌对二斑叶螨的致病性和对天敌智利小植绥螨的间接影响

Pathogenicity of Beauveria bassiana to Tetranychus urticae Koch(Acari: Tetranychidae) and Its Indirect Effects on Phytoseiulus persimilis(Acari: Phytoseiidae)

二斑叶螨是世界性害螨,为害多种经济作物和蔬菜。为明确球孢白僵菌和捕食螨联合应用防控二斑叶螨的可行性,本文测定了不同浓度球孢白僵菌GZGY-1-3孢子悬浮液对二斑叶螨的致病力,并用喷施球孢白僵菌16 h、24 h、36 h和48 h后的二斑叶螨分别饲喂智利小植绥螨,测定智利小植绥螨连续两代的致死率、生长发育及繁殖力变化。结果表明:二斑叶螨的校正死亡率随喷施球孢白僵菌孢子浓度的增加而增加,1×10^(8)孢子/mL浓度下球孢白僵菌对二斑叶螨的校正死亡率最高,此浓度下,球孢白僵菌对二斑叶螨的LT_(50)为5.0 d,同时球孢白僵菌对二斑叶螨的LC_(50)为1.37×10^(6)孢子/mL。智利小植绥螨取食被球孢白僵菌侵染的二斑叶螨后,在F_(0)代中,随喷菌时间的延长,智利小植绥螨的第二若螨、产卵前和世代历期均显著延长,雌成螨的单雌产卵量降低;但F_(1)代中,不同处理间,各虫态发育历期及单雌产卵量均无显著差异。本试验证明了对二斑叶螨具有高毒力的球孢白僵菌菌株,在安全期内对智利小植绥螨的亚致死影响较低。研究结果为实际生产中球孢白僵菌与智利小植绥螨联合防治二斑叶螨提供了理论支撑。

The spider mite Tetranychus urticae Koch(Acari:Tetranychidae)is a worldwide pest of economic crops and vegetables.In order to determine the feasibility of combined application of Beauveria bassiana and predatory mites to control T.urticae.The pathogenicity of B.bassiana(GZGY-1-3)conidial suspension with different concentrations to T.urticae was determined;the predatory mite Phytoseiulus persimilis Athias-Henriot(Acari:Phytoseiidae)was fed with T.urticae after spraying B.bassiana for 16 h,24 h,36 h and 48 h,respectively,then the lethal rate,growth and fecundity of P.persimilis were measured.The results indicated that the corrected mortality of T.urticae increased with the increase of conidia concentration of B.bassiana,the corrected mortality of T.urticae was the highest at the concentration of 1×10^(8) conidia/mL of B.bassiana,the LT50 of B.bassiana to T.urticae was 5.0 d under this conidia concentration of B.bassiana,and the LC_(50) of B.bassiana to T.urticae was 1.37×10^(6) conidia/mL.After feeding on T.urticae infected by B.bassiana,with the extension of spraying time,the deutonymph,preoviposition and generation duration of P.persimilis were significantly prolonged,and the oviposition per female decreased in the F0 generation;there was no significant difference in each developmental stage duration and oviposition per female among the treatments in the F_(1) generation.This study proved that B.bassiana GZGY-1-3 is a highly virulent strain to T.urticae,the sublethal effect on P.persimilis was low within the safety period.The results provide a theoretical support for the control of T.urticae by combined application of B.bassiana and P.persimilis.