金龟子绿僵菌对华北大黑鳃金龟幼虫的杀虫活性研究

虫生真菌是害虫的重要天敌之一。本文从华北大黑鳃金龟幼虫Holotrichia oblita (Fald.)分离出一株，并采用浸渍法初步研究了对华北大黑鳃金龟幼虫的杀虫活性。结果表明，分离出的虫生真菌为金龟子绿僵菌(Metarhizium anisopliae)菌株；随金龟子绿僵菌孢子浓度的升高, 华北大黑鳃金龟幼虫的感病死亡率增加,在浓度为2.1×104、1.9×105、2.2×106、2.0×107、1.8×108个孢子/ml时,幼虫的累计死亡率分别为20 %、65 %、90 %、100 %和100 %。用时间-剂量-死亡率模型(time-dose-mortality model ,TDM) 对幼虫的致病力数据进行模拟,所建模型均顺利通过Hosmer-Lemeshow拟合异质性检验,表明模型拟合良好,并由模型估计出了该菌株对华北大黑鳃金龟幼虫的致死剂量与致死时间。结果说明该菌株对防治华北大黑鳃金龟幼虫具有较强的应用潜力。

The pathogenicity of an isolate of the fungus Metarhizium anisopliae against the larvae of Holotrichia oblita (Fald.)

Entomogenous fungi is one of the important resources of natural enemies of the insects. The pathogenicity of an isolate of the fungus Metarhizium anisopliae ,originally derived from Holotrichia oblita (Fald.) , against the larvae of them , was studied in the laboratory by immersing larvae into serial concentrations of the fungus. The results showed that the mortality of the larvae caused by infection of Metarhizium anisopliae increased with the concentration of conidial suspension and the time after treatment.The concentration treatment of 2.1×104、1.9×105、2.2×106、2.0×107、1.8×108 conidias / mL caused 20 %,65 %,90 %,100 % and 100 % mortality respectively. A time-dose-mortality model was used to analyze the bioassay data and the model fitted the data well , resulting in parameters for estimating the time and dose effects. The results explained the potential of the isolate of Metarhizium anisopliae for use in microbial control of the larvae of Holotrichia oblita (Fald.).