Economic performance of Parasitoid-Based Biological Control for Fall Armyworm (Spodoptera frugiperda) in Smallholder Maize Systems in Kenya

Nine years after its invasion, fall armyworm ( Spodoptera frugiperda , FAW) still remains a major constraint to maize production and food security in sub-Saharan Africa. While augmentative biological control has been promoted in national and regional FAW management strategies, evidence of its farm-level economic performance is limited. This study evaluated the agronomic and economic outcomes of using egg parasitoids ( Telenomus remus and Trichogramma chilonis ) in smallholder maize systems in Kenya. We surveyed 403 households across five agro-ecological zones, comparing parasitoid-based control against chemical pesticides and no active control using ex-post cost-benefit analysis and multivariate regression models. Results indicate that in agro-ecological Zones I-III, parasitoid-based FAW management led to significantly higher maize yields, total revenue, and net farm benefits compared with both pesticides use and no control. These economic gains were driven by improved yields and lower pest management costs, as farmers reduced pesticide and spraying labor expenses. In contrast, no significant differences in yield or economic outcomes were detected in Zones IV and V, where low seed rates constrained a yield potential. Overall, the findings demonstrate that parasitoid-based biological control is a profitable, sustainable component of integrated pest management in maize-based smallholder systems. By improving net returns while reducing reliance on synthetic pesticides, this approach offers a viable pathway for strengthening farm profitability and food security for smallholders.