Empirical Evaluation of the Effectiveness of Push-Pull Technology for Fall Armyworm Management in Maize in the South West Zone

Fall armyworm (Spodoptera frugiperda) has devastated maize production across sub-Saharan Africa since its arrival in 2016, and push-pull technology, using Napier grass as a border trap crop and Desmodium spp. as intercrop, offers a chemical-free management approach whose effectiveness under South West Nigerian conditions requires empirical validation. This study empirically evaluated push-pull technology for fall armyworm management in maize in Oyo and Osun States, South West Nigeria. A randomised block design experiment with four treatments (maize sole crop, push-pull with silverleaf Desmodium, push-pull with green leaf Desmodium, and calendar insecticide spray) was conducted over two growing seasons (2022 and 2023) at six on-farm sites per treatment. Fall armyworm leaf damage ratings (Davis scale), larval counts per plant, maize grain yield, and economic analysis were the primary outcome measures. Results showed that both push-pull treatments reduced mean fall armyworm leaf damage scores by 47 to 54 percent compared to unprotected sole maize. Grain yield in push-pull plots was 31 to 38 percent higher than sole crop plots. Push-pull with silverleaf Desmodium performed comparably to the insecticide spray treatment for larval density control (0.8 versus 0.6 larvae per plant respectively). The economic advantage of push-pull over chemical spray was 34,800 naira per hectare in year two. The study fills a geographical validation gap and recommends push-pull technology for fall armyworm management in the South West zone maize belt.

Keywords: push-pull technology, fall armyworm, Spodoptera frugiperda, maize, South West Nigeria