Toward Sustainable Management of Spodoptera frugiperda (Lepidoptera: Noctuidae): A Review on the Role of Endophytic Fungi in Crop Protection

The fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous pest that has rapidly expanded across Africa, Asia, and Oceania, threatening food security and agricultural productivity. Reliance on synthetic insecticides for FAW management is increasingly challenged by insecticide resistance, environmental contamination, and adverse effects on non-target organisms and human health. This review synthesizes current knowledge on the potential of endophytic fungi as a sustainable strategy for FAW management. Following a systematic literature search, 59 original research articles published over the past 41 years were evaluated. These studies investigated 44 fungal species across 37 host crops, with Zea mays representing the most extensively studied system. The fungal species most frequently assessed were Beauveria bassiana, Metarhizium anisopliae sensu lato (s.l.), and Epichloe coenophialum. Overall, several fungal species successfully colonized plant tissues and reduced FAW performance through increased larval mortality, delayed development, and reduced feeding. These effects were associated with the production of bioactive secondary metabolites, induction of plant defense responses, and alteration of volatile organic compound emissions. Despite these promising findings, important knowledge gaps remain. Studies assessing effects on non-target organisms and natural enemies are scarce, and field validation remains limited. Research efforts are also geographically biased, with relatively few studies conducted in Africa despite the continent experiencing some of the highest FAW-related losses. Future research should prioritize field evaluations, multitrophic interaction studies, investigations in underrepresented regions, and socio-economic analyses to support farmer adoption. Addressing these gaps will be critical for determining the practical role of endophytic fungi in sustainable FAW management.