黄绿绿僵菌对两种稻田蜘蛛捕杀褐飞虱作用的影响

在室内研究了喷施黄绿绿僵菌Metarhizium anisopliae var. acridum Driver et Milner孢子悬液对稻田蜘蛛捕杀褐飞虱作用的影响。结果表明，黄绿绿僵菌不感染拟水狼蛛Pirata subpiraticus Bsenberg et Strand和食虫沟瘤蛛Ummeliata inse cticeps Bsenberg et Strand，只对蜘蛛喷施菌液不影响它们的捕杀褐飞虱的能力。而对褐飞虱喷施黄绿绿僵菌液后，褐飞虱活力明显下降，导致蜘蛛对其捕杀效果显著提高。在喷施黄绿绿僵菌106 、107、108/mL孢子浓度后，拟水狼蛛的平均捕杀量分别为10.5头/d、11.1头/d和11.4头/d，食虫沟瘤蛛的平均捕杀量分别为3.8头/d、4.3头/d和4.7头/d，均显著大于对照组。对蜘蛛和褐飞虱同时喷施黄绿绿僵菌不影响前者的捕杀力。这些结果提示，在稻田施用黄绿绿僵菌防治稻飞虱对蜘蛛天敌没有不良影响。

Effects of the entomopathogenic fungus Metarhizium anisopliae var. acridum on the predation of two paddyfield spiders on the brown planthopper,Nilaparvata lugens Stal (Homoptera: Delphacidae)

Laboratory studies were conducted to determine the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae var. acridum Driver et Milner on paddyfield spiders Pirata subpiraticus Bsenberg et Strand and Ummeliata insecticeps Bsenberg et Strand, to evaluate the effects of the fungus on the predating efficiency of the spiders on the brown planthopper, Nilaparvata lugens Stal. The results indicated that Metarhizium anisopliae var. acridum had no pathogenicity on both Pirata subpiraticus and Ummelita insecticeps. However, the activity of brown planthoppers decreased apparently after being infected with conidia of Metarhizium anisopliae var. acridum, that caused increase of the predating efficiency of the paddyfield spiders. At oncentrations of 10⁶, 10⁷, 10⁸ conidia/mL of Metarhizium anisopliae var. acridum, the mean predating efficiency of Pirata subpiraticus on brown plathoppers were 10.5 heads/d, 11.1 heads/d and 11.4 heads/d respectively; for Ummeliata insecticeps, the mean predating efficiency on plan thoppers were 3.8 heads/d, 4.3 hoppers/d and 4.7 hoppers/d respectively. Statistical analysis indicated that the differences between the treatments and control were significant. The predating efficiency of the spiders on planthopper increased slightly with the increasing of conidia concentrations of Metarhizium aniso pliae var. acridum.