微生物杀虫剂联合施用对草地贪夜蛾幼虫的防治效果

为提高微生物杀虫剂对草地贪夜蛾Spodoptera frugiperda的防治效果，利用球孢白僵菌Beauveria bassiana IPPB343、IPPB1237与金龟子绿僵菌Metarhizium anisopliae IPPM330189三种昆虫病原真菌，斜纹夜蛾核型多角体病毒（Spodoptera litura nuclear polyhedrosis viruses，SLNPV）、甘蓝夜蛾核型多角体病毒（Mamestra brassicae nuclear polyhedrosis viruses，MBNPV）2种昆虫病毒和短稳杆菌Empedobacter brevis昆虫病原细菌，设置9种联合施用药剂组合，评价6种微生物杀虫剂单独使用以及不同药剂联合施用组合对草地贪夜蛾幼虫的毒力以及田间防治效果。结果表明，与6种微生物杀虫剂单独使用相比，9种联合施用组合均能提升微生物杀虫剂对草地贪夜蛾的毒力水平与田间防治效果。施药后7 d时，金龟子绿僵菌IPPM330189+MBNPV药剂组合的防治效果最好且增效最明显，对草地贪夜蛾的田间防治效果达到88.75%，协同毒力指数为23.78。此外，金龟子绿僵菌IPPM330189+短稳杆菌悬浮剂药剂组合施药后7 d对草地贪夜蛾的田间防治效果达到87.45%，协同毒力指数也可达到21.72。表明微生物杀虫剂联合施用可显著提升其对草地贪夜蛾的防治效果。

Control effect of insect pathogenic fungi combined with biogenic insecticides on the larvae of fall armyworm Spodoptera frugiperda

To improve the control effect of microbial insecticides against fall armyworm Spodoptera frugiperda, three types of insect pathogenic fungi, including Beauveria bassiana strains IPPB343, IPPB1237, and Metarhizium anisopliae strain IPPM330189, in addition to two kinds of insect viruses, S. litura nuclear polyhedrosis virus (SLNPV) and Mamestra brassicae nuclear polyhedrosis viruses (MBNPV), along with one species of insect bacteria Empedobacter brevis were utilized. Nine pesticide combinations, including fungi+bacteria and fungi+viruses, were established. The toxicity and field control effects of six microbial insecticides used individually and in different combinations of pesticides against S. frugiperda larvae were evaluated. The results showed that compared to the use of six microbial insecticides alone, all nine mixed combinations exhibited enhanced toxicity level and field control effectiveness against S. frugiperda. Seven days post-application, the combination of M. anisopliae IPPM330189 and MBNPV displayed the best control effect, achieving an 88.75% field control rate with a synergistic toxicity index of 23.78. Furthermore, the combination of M. anisopliae IPPM330189 and E. brevis suspension achieved an 87.45% control rate with a synergistic toxicity index of 21.72. These results indicated that the mixed use of microbial insecticides significantly enhances control efficacy against S. frugiperda in the field.