Bacillus thuriengiensis (Bt), Beauveria bassiana (Bb) and Heliothis armigera nuclear polyhedrosis viruses (HaNPV) are typical microbial pesticides of bacterium, fungus and virus. In order to identify the toxicity of microbial pesticides to silkworm, this study measured the toxicity of these three typical microbial pesticides to silkworm, Bom-byx mori L.. The results showed that LC50 of the Bt technical and Bb technical to 2nd instar larvae of silkworm are 1.33×105 CFU·mL-1, 1.14×106 CFU·mL-1, respectively;LC50of HaNPV technical concentrates to 2nd instar larvae of silkworm is higher than 1.00×108 PIB·mL-1. At the same time, some key indicators, such as cocooning rate, the rate of dead worm cocoon, cocoon weight, cocoon shell weight, are detected through further experiment. The result showed that except HaNPV technical concentrates,both high concentration of Bt technical and Bb technical have sig-nificant influence on cocooning rate and the rate of dead worm cocoon of silkworm. However, the three typical mi-crobial pesticides have no significant influence on cocoon weight, cocoon shell weight and pupal weight.%苏云金芽孢杆菌、球孢白僵菌以及棉铃虫核型多角体病毒是细菌类、真菌类和病毒类微生物农药的典型代表.为了明确微生物农药对家蚕的毒性影响,选取以上3种典型微生物农药,分别探究其对家蚕的毒性.结果显示:苏云金杆菌原药对家蚕LC50值为1.33×105CFU·mL-1;球孢白僵菌原药对家蚕LC50值为1.14×106 CFU·mL-1;棉铃虫核型多角体病毒母药对家蚕LC50值大于1.00×108 PIB·mL-1.与此同时,通过进一步试验,明确了以上3种微生物农药对家蚕结茧率、死笼率、全茧量、茧层量等关键指标的影响.结果显示:除了棉铃虫核型多角体病毒母药,高浓度苏云金杆菌原药、球孢白僵菌原药对家蚕的结茧率和死笼率均具有显著影响;3种微生物农药对家蚕产茧能力指标全茧量、茧层量以及蛹重均无显著性影响.
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