## 1 Introduction  
Worldwide, about an 18-26% reduction in crop production is due to insect pests, which mostly occurs in the fields before harvest [1]. The Fall armyworm _Spodoptera frugiperda_ ([PERSON]) (Lepidoptera: Nocutiidae), from the tropical and subtropical zones of America [2], is a catastrophic insect pest of economic importance [3]. This voracious insect has a polyphagous feeding nature in more than 80 host species, including many commercial crops such as maize, cotton, rice, soybean, bean, and other crops from the Gramineae family [4, 5, 3]. Until 2015, damage due to _S. frugiperda_ was reported only in America [6], but in the last few years, attacks have been reported in other parts of the world [5]. In late 2016 they were reported in Southern, Eastern, and Northern parts of Africa [6], which briskly expanded across the continent and, by late 2018 they were confirmed in almost 44 African countries [3]. By 2018, the presence of this insect pest was confirmed in Yemen and India,and by 2019, devastation due to this pest was confirmed in five more Asian countries, including China [7]. The destruction generated by _S. frugiperda_ relies on the geographic region, seed variety, planting time, and fundamental cultural habits in and around the field, although abiotic factors have an effect on egg and initial larval stage mortality during a rainy season, and with various predators during a dry season [4]. _S. frugiperda_ is treated as a crucial insect pest of maize, which is the third most essential cereal crop worldwide with the highest economic value in terms of production and nutrition [6]. It causes extensive damage to maize plants by feeding on young leaf whorls, corn cobs, and tassels [3]. Younger larvae prefer epidermal leaf tissue and produce holes in them, which is the typical damage sign by these insect pests. Deadheart is caused by feeding on young plants through the whorls. Older larvae in the whorls of grown-up plants feed on cobs or kernels, which reduces yield quality and quantity [2]. The presence of various generations, their migration, and the potential to feed on a vast range of host plants make this insect one of the most difficult pests to control [2]. Synthetic/chemical insecticides or genetically modified crops have been used to control insect pests [2]. Although these control measures are very efficient, their extensive usage has caused ecological issues, environmental contamination, development of resistance, and detrimental effects on human health [8]. Since the insects have gained resistance to various chemical insecticides, farmers are compelled to use recurrent application of large amounts of insecticides, which will lead to the accumulation of chemicals in agricultural fields [2]. Taken together, scientists in different parts of the world are forced to develop more environmentally safe, cost-effective, and reliable strategies to control insect pests [1]. The Integrated Pest Management (IPM) global program for agriculture is a holistic concept for approaching the crop production system as a whole process, rather than focusing only on pest elimination. This approach combines various techniques, including the use of resistant varieties, cultural manipulation, trap cropping, and biological control [1]. The latter is one of the techniques to control insect pests with the slightest environmental impact [9]. Cost-effectiveness, high yield, not being harmful to beneficial insects, and the release of fewer chemical residues into agricultural fields make entomopathogenic microorganisms excellent alternatives to chemical pesticides [1]. At present, different bacteria (_Bacillus_ spp., _Enterobacter_ spp., _Pseudomonas_ spp. _Paenibacillus_ spp., etc.) and fungi (_Beauveria_ sp., _Metrahizium_ sp., _Paecilomyces_ sp., _Isaria_ sp., _Lecanicillium_ sp., _Hirstella_ sp., etc.) are being applied as biocontrol agents [1,9].