Ecological Drivers of Fall Armyworm (Spodoptera frugiperda) Outbreak Dynamics in Maize-Growing Communities of Cross River State, South South Nigeria

Fall armyworm outbreaks in Nigerian maize farms have shown marked heterogeneity in frequency and severity across landscapes, suggesting that ecological factors mediate outbreak risk beyond simple host plant availability. Cross River State, with its complex mosaic of rainforest, secondary bush, and cultivated land, offers a diverse ecological context to study drivers of S. frugiperda population dynamics. This study examines ecological drivers of fall armyworm outbreak dynamics in maize-growing communities across Cross River State. Population density and infestation severity will be assessed on 75 maize farms across forest, transition, and open savanna zones at vegetative and tasseling stages over two cropping seasons. Natural enemy abundance will be concurrently sampled using pitfall and sticky traps. Land use composition within 2-km radii of each farm will be quantified from remote sensing data. Bayesian hierarchical modeling will test hypotheses about the relative contributions of natural enemy pressure, landscape diversity, weather variables, and farming system features to outbreak probability. This study is the first to apply landscape ecology methods to fall armyworm outbreak analysis in South South Nigeria, filling an important gap in understanding the spatial ecology of this invasive pest. Keywords: Spodoptera frugiperda, outbreak ecology, landscape drivers, Cross River State, Bayesian modeling