Reduced Fall Armyworm (Spodoptera frugiperda J.E. Smith) Infestation and Leaf Damage in Maize Fields Adjacent to Forested Margins in Two Districts of Malawi

Gift Thole, Trust Donga, Joyce Njoloma, Betserai Nyoka, Simon Mng’omba, Joseph Chimungu, Edward Missanjo, Samson Katengeza and Rhett Harrison

Background and Objective: Fall armyworm poses a major threat to maize production in Malawi. Forested field margins may influence pest incidence and crop damage, offering potential for sustainable pest management strategies. A study was conducted to assess the impact of forested field margins on fall armyworm incidence and leaf damage in maize in Lilongwe and Salima Districts in Malawi. Materials and Methods: A randomized block design involving maize fields adjacent to forested and non-forested margins was used. Nine plots per field were established for fall armyworm assessment, while vegetation diversity was evaluated using stratified plots for herbs, shrubs and trees. Data obtained was subjected to Analysis of Variance (ANOVA) at 5% significance level in GenStat, Odds ratio test in Statistical Package for Social Sciences (SPSS) and Renyi diversity profile in Biodiversity R. Results: The results revealed significantly fewer fall armyworms, infected plants and leaf damage in maize fields near forested margins compared to those farther away (p<0.001). Strong associations were observed between fall armyworm presence and plant infection/damage, with higher odds ratios in fields away from forests. Greater tree species richness (89 vs. 8 species) in forested margins likely contributed to reduced pest incidence and plant damage. Conclusions: The study demonstrated that proximity to diverse tree species significantly lowers pest infestations. This suggests that integrating forested field margins into agricultural landscapes can serve as a natural pest management strategy, reducing reliance on chemical pesticides and promoting sustainable farming.

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