Biological control of the fall armyworm Spodoptera frugiperda (J. E. Smith), (Lepidoptera: Noctuidae) globally: systematic review and meta-analysis

Abstract Background Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) popularly known as the fall armyworm, is a highly polyphagous invasive insect pest that has caused substantial yield losses since its spread outside the Americas. The growing development of resistance to insecticides, coupled with environmental concerns, has increased interest in biological control agents, including parasitoids and entomopathogens such as: bacteria, fungi, virus and nematodes, as sustainable components of integrated pest management. Results A systematic search (2016–October 2025) returned 327 unique records; after screening and full-text assessment, 31 studies comprising 63 trials met the eligibility criteria and were synthesized qualitatively and quantitatively. Fungi and nematodes comprised 12 and 8 of the reviewed studies, respectively, while entomopathogenic fungi (EPF) isolates were largely represented by Beauveria bassiana (12 trials) and Metarhizium anisopliae (7 trials). Meta-analysis revealed significant overall pooled effects for EPFs as a whole (pooled effect ≈ 27.14; 95% CI: 17.08–37.21), as well as for bacterial pathogens ( Bacillus spp., pooled effect = 25.23; 95% CI: 12.97–37.50), although heterogeneity across studies was very high for many subgroups (e.g., I² > 95% for EPF). Entomopathogenic nematodes (EPNs) elicited sizeable mean effect magnitudes on average across the studies that reported pooled effect sizes. However, species-level variability was great, and extreme heterogeneity between studies was commonplace. Parasitoids, in particular Trichogramma spp., Telenomus remus and Chelonus spp., also demonstrated promise for yield increases, largely in laboratory or small-scale field conditions, though evidence for consistent benefit remains limited. Conclusion The evidence supports the potential of EPFs, EPNs, Bacillus spp., and selected parasitoids as components of sustainable FAW management. However, high heterogeneity, variable field translation, formulation challenges, and geographic bias resultant from a concentration of studies in Egypt, Asia, and parts of Africa reduce certainty. Standardized bioassays, expanded field validation, and coordinated international research are needed to optimize agent selection, formulation, and IPM integration.