Patogenicity of entomopathogenic fungi to Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)

This study aimed to evaluate the pathogenicity, under laboratory conditions, of 49 isolates of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against Spodoptera frugiperda larvae. Insects (3rd instar caterpillars) were immersed in 1 × 109 conidia/mL suspensions of each of the isolates for 10 seconds. After that, caterpillars were individually placed in Petri dishes with artificial diet and incubated at 26 ± 1°C and 12 hours of photophase, and they were evaluated daily for ten days. The B. bassiana isolates were more efficient, mainly Unioeste 26 strain, which reached 44.5% mortality and generated the greatest number of conidia in production testing of the fungus. Despite the low mortality percentage, these studies showed the potential of entomopathogenic fungi as promising agents for the control of S. frugiperda.本研究旨在于实验室条件下，评估49株昆虫病原真菌（entomopathogenic fungi）——球孢白僵菌（Beauveria bassiana）与金龟子绿僵菌（Metarhizium anisopliae）对草地贪夜蛾（Spodoptera frugiperda）幼虫的致病力。供试3龄幼虫被置于浓度为1×10⁹ 分生孢子（conidia）/mL的各菌株悬浮液中浸泡10秒。随后将幼虫单独转移至铺有人工饲料（artificial diet）的培养皿（Petri dishes）中，于26±1℃、每日光照12小时的光照期（photophase）条件下培养，并连续10天每日开展观察评估。结果表明，球孢白僵菌菌株整体防治效果更优，其中尤以Unioeste 26菌株表现突出，其致病死亡率可达44.5%，且在真菌产孢试验中产生的分生孢子数量最多。尽管整体死亡率偏低，但本研究证实了昆虫病原真菌作为草地贪夜蛾生物防治潜力菌株的应用前景。