杀虫真菌与苏云金芽胞杆菌对草地贪夜蛾的联合室内杀虫活性研究

草地贪夜蛾Spodoptera frugiperda（J.E.Smith）是一种迁飞性重大害虫。为了弄清不同微生物联合使用对草地贪夜蛾的生防潜力，在室内条件下采用直接喷雾方法，测定了金龟子绿僵菌Metarhizium anisopliae CQMa421、球孢白僵菌Beauveria bassiana ZJU435和苏云金芽胞杆菌（Baci1lus thuringiensis，Bt）G033A两两之间对草地贪夜蛾幼虫的室内联合杀虫活性。结果表明：金龟子绿僵菌CQMa421与球孢白僵菌ZJU435悬浮液联合接种10 d后，1～3龄草地贪夜蛾幼虫校正死亡率分别为65.6%、58.8%和35.4%，都显著高于CQMa421和ZJU435单剂处理组。CQMa421与Bt联合接种5 d后，2龄草地贪夜蛾幼虫校正死亡率为82.6%，显著高于CQMa421（21.1%）和Bt（65.5%）单剂处理；ZJU435与Bt联合接种5 d后，2龄和4龄草地贪夜蛾幼虫校正死亡率为80.4%和68.6%，显著高于Bt和ZJU435单剂处理组。上述试验结果表明：不同杀虫真菌联合使用、杀虫真菌与Bt联合使用能有效提高对草地贪夜蛾幼虫的杀虫活性，为田间利用不同微生物农药有效防控草地贪夜蛾提供了依据。

Synergistic Effects of Fungal Insecticides and Baci1lus thuringiensis against Spodoptera frugiperda in Laboratory

Spodoptera frugiperda (J. E. Smith) is a global migratory pest. To evaluate the potential of combined microbial insecticides for control of S. frugiperda, the combinations of two microbial pesticides among Metarhizium anisopliae CQMa421, Beauveria bassiana ZJU435 and Baci1lus thuringiensis (Bt) G033A were investigated under laboratory conditions. The results showed that the combination of CQMa421-ZJU435 achieved the corrected mortality of 65.6%, 58.8% and 35.4% against the 1^st, 2^nd and 3^rd instar larvae, respectively, significantly higher than that in the treatments with CQMa421 or ZJU435 alone at 10 days post inoculation. Five days post inoculation of CQMa421-Bt, the corrected mortality of the 4^th instar larvae was 82.6%, significantly higher than that in the treatment with CQMa421 (21.1%) or G033A (65.5%) alone. Five days post inoculation of ZJU435-Bt, the corrected mortality of the 2^nd and 4^th instar larvae were 80.4% and 68.6%%, significantly higher than that in the treatment with ZJU435 or G033A alone. This indicates that combination of different fungal insecticides with Bt could effectively improve the insecticidal activity against S. frugiperdaa larvae. These results have paved the way for mixed application microbial pesticides for control of S. frugiperda in field.