Potential of Entomopathogenic Nematode HbSD as a Candidate Biocontrol Agent against Spodoptera frugiperda

Abstract

Spodoptera frugiperda is a highly destructive and polyphagous pest that causes severe damage to various crops, especially maize. The wide use of chemical insecticides to control S. frugiperda results in resistance against commonly used chemicals and resistant mutations will expand in populations accompanied by a spread to vulnerable areas. Consequently, more effective and friendly strategies must be explored to minimize losses caused by S. frugiperda. Entomopathogenic nematodes (EPN) are good candidates for the biological control of different species of insect pests, including S. frugiperda. In the current study, the infective capabilities of the EPN species HbSD, belonging to Hetrerorhabditis bacteriophora, were evaluated against S. frugiperda under laboratory, greenhouse and field conditions. In laboratory assays, HbSD was highly virulent against 3rd/5th instar larvae, which was related to HbSD concentration and exposure durations. In greenhouse assays, spraying aqueous HbSD also showed good performance in killing larvae on maize leaves. However, the virulence of HbSD decreased in field trials where many adverse factors affecting survival and efficacy were encountered by HbSD. Overall, our study provides an alternative EPN for the biological control of S. frugiperda with the potential to be developed as a sustainable option for efficient pest management.

Gene Cloning, Heterologous Expression, and In Silico Analysis of Chitinase B from Serratia marcescens for Biocontrol of Spodoptera frugiperda Larvae Infesting Maize Crops

“…The fall armyworm (FAW), Spodoptera frugiperda, is a widely adaptable pest that poses a significant threat to maize and various cereals in tropical and subtropical areas across the globe [1]. Originating from the Americas, recent incursion of the FAW into Africa, Asia, and Oceania has resulted in substantial reductions in yields of multiple food crops [2].…”

“…A prudent approach involves isolating entomopathogenic bacteria from infected insects and cultivating them to evaluate their insecticidal impact, either through cell cultures or the examination of potential secondary metabolites, such as toxins or enzymes. An example of employing bacterial cells against S. frugipedra is seen in a recent investigation conducted by Chen et al [1], who isolated entomopathogenic nematodes, specifically Heterorhabditis bacteriophora, demonstrating their effectiveness across laboratory, greenhouse, and field settings. Another example of utilizing secondary metabolites as insecticides is presented by Sun et al [2], where a fungal-derived Cyclosporin A demonstrated notable insecticidal efficacy (LC50 = 9.69 µg/g) against FAWs by effectively inhibiting calcineurin (CaN) activity, resulting in significant suppression of the pests.…”