The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is a devastating pest of maize, difficult to manage using a single pest management tactic. The entomopathogenic fungus (EPF), Metarhizium anisopliae being an eco-friendly component, could be an effective tool for managing this notorious pest owing to its preferred habitat, principally the whorl region. Metarhizium anisopliae (TNAU-MA-GDU) isolated from FAW was evaluated against 2nd instar larvae of S. frugiperda reared under laboratory conditions. The pathogenicity and infection process were also studied through scanning electron microscope (SEM). The LC50 value for M. anisopliae isolate TNAU-MA-GDU was recorded as 5.8 × 104 spores ml−1 against the second instar larvae of S. frugiperda. SEM observations on the infection process revealed the adherence of the conidia on the head, cuticular ornamentations of the thorax, sensory seta, and legs at 24 h post-infection (hpi). Formation of germ tube and appressoria was observed from 48 hpi with subsequent hyphal development at 72 hpi. Complete networking of mycelium and conidiogenesis observed after 168 hpi. An understanding of fungal–host interactions at the ultramicroscopic levels could reform present tactics for developing hyper-virulent EPF strains.

中文翻译：

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绿毒菌、绿僵菌 (Metschnikoff) Sorokin (Ascomycota: Hypocreales) 对玉米秋粘虫、草地贪夜蛾 (JE Smith) (鳞翅目: 夜蛾科) 的致病性、超微结构生长和发育

秋粘虫 (FAW)、草地贪夜蛾 (JE Smith) (鳞翅目：夜蛾科) 是一种破坏性的玉米害虫，很难使用单一的害虫管理策略进行管理。昆虫病原真菌 (EPF)，绿僵菌是一种生态友好型成分，由于其首选栖息地，主要是轮生区，因此可以成为管理这种臭名昭著的害虫的有效工具。对从 FAW 中分离出的绿僵菌 (TNAU-MA-GDU) 与在实验室条件下饲养的 S. frugiperda 的第 2 龄幼虫进行了评估。还通过扫描电子显微镜（SEM）研究了致病性和感染过程。M. anisopliae 分离株 TNAU-MA-GDU 的 LC50 值记录为 5.8 × 104 孢子 ml-1 对 S. frugiperda 的第二龄幼虫。对感染过程的 SEM 观察显示，在感染后 24 小时 (hpi)，分生孢子附着在头部、胸部、感觉刚毛和腿部的表皮装饰。从 48 hpi 开始观察到胚管和附着胞的形成，随后在 72 hpi 时菌丝发育。168 hpi 后观察到菌丝体和分生孢子形成的完整网络。在超微观水平上了解真菌-宿主相互作用可以改变目前开发高毒力 EPF 菌株的策略。