Bio-efficacy of seed and leaf extracts of Azadirachta indica (neem) and Jatropha curcas (physic nut) against Spodoptera frugiperda (Fall armyworm) infestation in maize fields

Abstract Background The Fall armyworm, originally indigenous to the tropical and subtropical regions of the Americas, causing significant reductions in maize productivity. This study evaluated the bio-efficacy of seed and leaf extracts of Azadirachta indica (neem) and Jatropha curcas (physic nut) against Fall armyworm infestation under field conditions. The experiment was arranged in a randomized complete block design with five treatments. A. indica seed extract (SEAI), A. indica leaf extract (LEAI), J. curcas seed extract (SEJC), J. curcas leaf extract (LEJC) and an untreated control. The treatments were applied at a concentration of 150 g/L and replicated three times. Data were collected on larval populations, percentage infestation, leaf damage and grain yield. Results Results showed that, SEAI significantly reduced FAW larval population to 0.67 larvae per 10 maize plants after the third spray and recorded the lowest maize damage (10.0%,), in comparison, with untreated control plots (66.7%). The maize plots treated with seed extract of A. indica exhibited the lowest leaf damage score of 1.33. Grain yield was significantly enhanced by botanical treatments with SEAI producing the highest yield (2781.73 kg/ha), followed by SEJC (2581.73kg/ha), LEAI (2541.67 kg/ha), and LEJC (2180.20 kg/ha) while untreated control yielded 1666.10 kg/ha. Conclusion This suggests that A. indica and J. curcas extracts may serve as alternatives for synthetic insecticides for the management of Fall armyworm to enhance maize yields.