Entomopathogenic Fungi as Orchestrators of Plant Defense, Growth, and Stress Tolerance—A Comprehensive Review

Entomopathogenic fungi (EPF), including Beauveria spp., Metarhizium spp., Lecanicillium spp., and Isaria spp., help manage pest populations through direct infestation and insecticidal toxin production. Beyond pest control, they enhance plant growth and overall health, which makes them essential components of sustainable agriculture. EPF orchestrates systemic acquired resistance (SAR) and induced systemic resistance (ISR) via salicylic acid (SA) and jasmonic acid (JA) signalling pathways, respectively. Through these mechanisms, EPF promotes plant resilience against both biotic (pathogens and pests) and abiotic stresses (drought, nutrients, heat, and salinity), while improving nutrient uptake, hormone production, and soil quality. In addition, the secondary metabolites produced by EPF strengthen plant defense and stress tolerance. Their ability to persist as endophytes ensures long-term crop protection and growth stimulation. Incorporating EPF into Integrated pest management as a biocontrol agent reduces the reliance on chemical pesticides, enhances plant resistance, and supports environmental sustainability. This review examines the multifaceted contributions of EPF as a bioinoculant that promotes crop health and tolerance to biotic and abiotic stresses, and discusses the prospects for large-scale commercial applications.