Mycosis on the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), infecting maize was observed in research farm of Regional Agricultural Research Station, Anakapalli from October 2019 to February 2020. High relative humidity (94.87%), low temperature (24.11 °C), and high rainfall (376.1 mm) received during the month of September 2019 predisposed the larval instars for fungal infection and subsequent high relative humidity and low temperatures sustained the infection till February 2020. An entomopathogenic fungus (EPF) was isolated from the infected larval instars as per standard protocol on Sabouraud’s maltose yeast extract agar and characterized based on morphological and molecular analysis. The fungus was identified as Metarhizium (Nomuraea) rileyi based on ITS sequence homology and the strain was designated as AKP-Nr-1. The pathogenicity of M. rileyi AKP-Nr-1 on S. frugiperda was visualized, using a light and electron microscopy at the host-pathogen interface. Microscopic studies revealed that all the body parts of larval instars were completely overgrown by white mycelial threads of M. rileyi, except the head capsule, thoracic shield, setae, and crotchets. The cadavers of larval instars of S. frugiperda turned green on sporulation and mummified with progress in infection. In vitro pathogenicity tests revealed the potential of AKP-Nr-1 strain of M. rileyi in management of S. frugiperda. The results indicated the potential of M. rileyi AKP-Nr-1 as biocontrol agent for management of the fall armyworm. This AKP-Nr-1 strain of M. rileyi needs further evaluation under field conditions to evaluate its efficacy against S. frugiperda and its effects on other hosts.

中文翻译：

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研究霉菌病金龟子绿僵菌（野村）rileyi在草地夜蛾在印度安得拉邦为害玉米

从2019年10月至2020年2月在安纳卡帕利地区农业研究站的研究农场观察到秋季粘虫，夜蛾夜蛾（JE Smith）（鳞翅目：Noctuidae）的真菌感染玉米。相对湿度高（94.87％），低温（ 24.11°C），2019年9月收到的高降雨（376.1 mm）导致幼虫幼虫真菌感染，随后较高的相对湿度和低温持续感染直至2020年2月。从中分离出一种昆虫病原性真菌（EPF）按照Sabouraud的麦芽糖酵母提取琼脂上的标准规程感染受感染的幼虫，并根据形态学和分子分析对其进行鉴定。基于ITS序列同源性，将该真菌鉴定为利氏根霉（Metrahizium rileyi），并将该菌株命名为AKP-Nr-1。使用光-电子显微镜在宿主-病原体界面处观察到黎氏支原体AKP-Nr-1对弗氏链球菌的致病性。显微镜研究表明，幼虫龄期的所有身体部位都被里氏木霉的白色菌丝丝完全长满，除了头部的囊，胸盾，刚毛和小钩。Srug frugiperda幼虫的尸体在孢子形成时变成绿色，并随着感染的进展而木乃伊化。体外致病性测试表明，利氏甲烷八叠球菌AKP-Nr-1菌株在治疗Srug frugiperda中具有潜力。结果表明M. rileyi AKP-Nr-1作为生防剂管理秋季粘虫的潜力。需要进一步在田间条件下评估此rileyi菌株的AKP-Nr-1菌株，以评估其对Srug frugiperda的功效及其对其他宿主的影响。