Sunnhemp as an alternative to silverleaf desmodium in push-pull systems for fall armyworm management in sweet maize

AbstractThis study evaluated the effectiveness of two companion cropping systems maize + silverleaf desmodium (Desmodium uncinatum) and maize + sunnhemp (Crotalaria juncea) against fall armyworm in sweet maize, compared to a biopesticide treatment (maize + Bacillus thuringiensis) and conventional maize monoculture. Both intercrops significantly reduced larval abundance, plant infestation, leaf damage, and egg mass numbers compared to the monoculture. The silverleaf desmodium intercrop showed the lowest infestation (6.8 ± 0.9%), while sunnhemp performed comparably, indicating strong “push” effects against ovipositing moths. Egg mass counts were highest in the monoculture, suggesting altered oviposition behavior in the intercrops. Yield and ear quality greatly improved in the intercropped systems, with maize + silverleaf desmodium (5.02 t ha-1) and maize + sunnhemp (4.9 t ha-1) outperforming the monoculture by 9.7 and 7.3%, respectively. Principal component analysis confirmed clear separation among systems, linking reduced pest pressure to higher yield. These findings demonstrate that leguminous companion cropping systems offer sustainable, ecologically-based alternatives to insecticide-dependent fall armyworm management while improving crop performance in sweet maize production systems.