The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), was recorded for the first time in Pakistan in 2019, and now it has spread in several regions, i.e., Punjab and Sindh, affecting maize production. Farmers are using widely synthetic pesticides to control the pest. Further, the resistance development in insects and the non-target effect of chemicals on the environment and humans pose serious threats of using insecticides. The use of entomopathogenic fungi (EPF) is being considered an important tool in integrated pest management program. The main objective of this study was to check the impact of different conidial concentrations of Metarhizium anisopliae fungus on the nutritional physiology of S. frugiperda. The dose-dependent effect of tested EPF was observed, and the highest concentration (1 × 109 conidia/ml) considerably affected nutritional parameters. Reduced relative consumption rate (21.7%), relative growth rate (19.5%), the efficiency of conversion of ingested food (24.2%), and approximate digestibility (16.3%) were observed in treated larvae compared to the untreated by using a higher concentration of EPF. Pupal weight was also found lower (77.9 mg and 84.2 mg, respectively), when larvae were treated by 1 × 109 and 1 × 108 conidia/ml concentrations of EPF. Further, 46.7% of larvae were found dead with this conidial concentration. This study suggests that the application of a higher concentration of M. anisopliae could be an effective option to control S. frugiperda. The EPF can enhance the integrated pest management programs and could be useful in reducing the environmental impact of synthetic insecticides.

中文翻译：

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绿僵菌对秋粘虫、草地贪夜蛾（JE Smith）（鳞翅目：夜蛾科）营养生理的影响

秋粘虫草地贪夜蛾（JE Smith）（鳞翅目：夜蛾科）于2019年首次在巴基斯坦记录，现已在旁遮普省和信德省等多个地区蔓延，影响玉米生产。农民正在广泛使用合成杀虫剂来控制害虫。此外，昆虫的抗药性发展以及化学品对环境和人类的非靶向作用对使用杀虫剂构成严重威胁。昆虫病原真菌 (EPF) 的使用被认为是综合虫害管理计划的重要工具。本研究的主要目的是检查绿僵菌不同分生孢子浓度对草地贪夜蛾营养生理的影响。观察到测试的 EPF 的剂量依赖性效应，最高浓度（1 × 109 分生孢子/ml）显着影响营养参数。与未处理的幼虫相比，使用较高浓度处理的幼虫观察到相对消耗率 (21.7%)、相对生长率 (19.5%)、摄入食物的转化效率 (24.2%) 和近似消化率 (16.3%) 降低公积金局。当幼虫用 1 × 109 和 1 × 108 分生孢子/ml 浓度的 EPF 处理时，蛹的重量也较低（分别为 77.9 毫克和 84.2 毫克）。此外，在这种分生孢子浓度下，发现 46.7% 的幼虫死亡。这项研究表明，应用更高浓度的 M. anisopliae 可能是控制 S. frugiperda 的有效选择。