Evaluation of Native Entomopathogenic Fungi for the Control of Fall Armyworm (Spodoptera frugiperda) in Thailand: A Sustainable Way for Eco-Friendly Agriculture.

Julius Rajula,Jaturong Kumla,Aneta A Ptaszynska,Nakarin Suwannarach,Patcharin Krutmuang,Supamit Mekchay,Malee Thungrabeab,Sarayut Pittarate

doi:10.3390/jof7121073

Abstract

Fall armyworm, Spodoptera frugiperda, entered Thailand in late 2018 and has now spread in several regions, with devastating effects in maize and rice production, which are some of the most important cereals in the world. Since then, farmers have utilized the available chemical insecticides to try to control it, but their efforts have been futile. Instead, they have ended up using extraordinary dosages, hence threatening non-target species and other fauna and flora, as well as being costly. In this regard, research has been ongoing, aiming to come up with eco-friendly solutions for this insect. We surveyed and collected various isolates of native entomopathogenic fungi intending to test their efficacy against fall armyworm. Six isolates of entomopathogenic fungi were obtained and identified to Beauveria bassiana based on morphological characteristics and multi-gene phylogenetic analyses. Thereafter, the six isolates of B. bassiana were used to perform efficacy experiments against fall armyworm. Additionally, the glycosyl transferase-like protein 1 (GAS1) gene was analyzed. Consequently, all the isolates showed efficacy against S. frugiperda, with isolate BCMU6 causing up to 91.67% mortality. Further, molecular analysis revealed that all the isolates possess the GAS1 gene, which contributed to their virulence against the insect. This is the first report of utilizing native entomopathogenic B. bassiana to manage S. frugiperda in Thailand, with the revelation of GAS1 as a factor in inducing virulence and cuticle penetration. This study has provided valuable information on the potential development of Beauveria bassiana as an eco-friendly bioinsecticide for the management of fall armyworm in Thailand.

Highlights

IntroductionMaize ranks among the topmost commercially produced and utilized cereals globally
Maize ranks among the topmost commercially produced and utilized cereals globally.Firstly, it is used as human and animal feed
We confirmed that our indigenous fungal isolates are B. bassiana through morphological observations as well as multi-gene molecular analyses

Summary

Introduction

Maize ranks among the topmost commercially produced and utilized cereals globally. It is used as human and animal feed. Maize production has not met the needs of Thailand, causing more to be imported [3]. Rice is a staple food in many countries in the world, including Thailand. Due to pests and diseases, global warming, and increased drought, maize and rice production are threatened [1]. In late 2018, some of the fields of maize and rice in several provinces of Thailand and Myanmar were already invaded by the fall armyworm, and since losses have been incurred [6,7]

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