Management of Fall Armyworm (Spodoptera frugiperda) Through Combined Plant Extracts and Microbial Biocontrol Agents

The fall armyworm (FAW), <i>Spodoptera frugiperda</i>, poses a major threat to global maize production. Reliance on synthetic pesticides has contributed to pest resistance and environmental degradation, underscoring the need for sustainable alternatives. In this study, ethanolic extracts of neem (<i>Azadirachta indica</i>) and moringa (<i>Moringa oleifera</i>), together with maize-associated bacterial isolates, were evaluated for their biocontrol potential against fall armyworm. Gas chromatography-mass spectrometry (GC-MS) analysis for bioextract identification revealed tissue-specific chemical diversity, identifying eight key phytochemicals, including <i>octadecanoic acid</i>, <i>trimethyl fluorosilane</i>, and <i>hexadecanoic acid</i> in neem, and <i>trimethyl fluorosilane</i>, <i>ethyl oleate</i>, <i>ethyl (9Z</i>,<i>12Z)</i>, <i>octadecanoic acid</i>, and <i>benzenedicarboxylic acid</i> in moringa extracts. Eighty-nine bacterial isolates were screened for extracellular enzyme activities (cellulase, chitinase, glucanase, and protease) and siderophore production, among which four strains, DR-55 (<i>Bacillus subtilis</i>), HL-7 (<i>Bacillus cereus</i>), HL-37 (<i>Bacillus cereus</i>), and DR-63 (<i>Enterobacter</i> sp.), exhibited >50% biocontrol efficacy under greenhouse conditions. A strong correlation (r = 0.88) was observed between in vitro antagonistic activity and greenhouse performance, validating the screening approach. Fall armyworm mortality was the highest in larvae (up to 80%), moderate in pupae (15-17%), and the lowest in adults (6-7%), respectively. Overall, plant bio-extracts and maize-associated microbial isolates represent a promising, non-hazardous strategy for sustainable fall armyworm management while preserving maize plant health.