"Entomopathogenic microbial potential in the management of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Maize Production

Abstract

This manuscript investigates the potential of entomopathogenic microbial inoculants for the sustainable management of the fall armyworm, Spodoptera frugiperda (J.E. Smith), a major pest threatening maize (Zea mays L.) production in sub-Saharan Africa. The study evaluated biochar-based microbial formulations containing Bacillus thuringiensis, Pseudomonas putida, Klebsiella variicola, Trichoderma spp., and arbuscular mycorrhiza for their effectiveness in pest suppression and enhancement of maize growth. Molecular characterization confirmed the identity of the bacterial isolates, while laboratory bioassays demonstrated strong insecticidal activity, particularly from Bacillus thuringiensis, which produced the highest larval mortality against S. frugiperda. Greenhouse experiments further showed that biochar-based microbial treatments significantly reduced larval survival and leaf damage compared with untreated controls. Field trials conducted under natural infestation conditions revealed that integrated treatments combining moderate NPK fertilization, mycorrhiza, biochar, and B. thuringiensis significantly improved maize growth, chlorophyll content, and grain yield. The results demonstrate that biochar-based microbial consortia can simultaneously enhance soil fertility, plant vigor, and pest suppression. These findings highlight the potential of integrating entomopathogenic microbes with soil amendments as an environmentally sustainable alternative to chemical insecticides within integrated pest management (IPM) systems for maize production.