粘虫颗粒体病毒与苏云金杆菌联合作用对甜菜夜蛾的影响

以甜菜夜蛾为试虫，测定了粘虫颗粒体病毒（PuGV-Ps）对苏云金杆菌（Bt）毒力的增效作用。结果表明PuGV对甜菜夜蛾没有致毒作用，但Bt中加入PuGV后可以提高Bt对甜菜夜蛾的毒力，甜菜夜蛾致死中量LC50由Bt单剂的1．094mg／mL下降到0．862mg／mL，共毒系数达127。亚致死剂量Bt处理甜菜夜蛾影响了幼虫的生长发育，表现为幼虫生长量相对减少、蛹重下降、化蛹率降低和化蛹历期延长，添加了PuGV-Ps后进一步增强了Bt对甜菜夜蛾的生长发育的抑制作用。甜菜夜蛾中肠蛋白酶活性测定结果表明，PuGV-Ps对甜菜夜蛾中肠酶活性具有抑制作用；昆虫同时取食PuGV-Ps和Bt后，中肠酶液总蛋白酶活力都有所下降，在中肠酶液最适pH范围内蛋白酶活力抑制作用最明显。

Impact of Bacillus thuringiensis and Pseudaletia unipuncta Granulovirus-Ps on Spodoptera exigua

Enhancement of toxicity of Bacillus thuringiensis （Bt） with Pseudaletia unipuncta Granulovirus-Ps （PuGV-Ps） was dem- onstrated by bio-assays employing larvae of S. exigua. Combinations of Bt and PuGV-Ps were synergistic and enhanced toxicity of Bt while PuGV-Ps represented no effect to the larve. The co-toxicity coefficients （CTC） of Bt combined with PuGV-Ps was 127. Sub - deadly dosage of Bt influenced the larval growth of S. exigua, with less weight of larvae and pupae, delay of pupating and lower ratio of pupation. PuGV-Ps also enhanced the effect of Bt on the development of larvae. The proteolytic activity of midgut juice from Spodotera exigua was influenced by PuGV-Ps. When larvae of S. exigua swallowed the feed contain some Bt and PuGV-Ps, the total proteolysis was reduced for some degree by PuGV-Ps under the suited pH value of midgut juice.