Synergistic Effects of Maize Volatiles on Pheromone Trap Captures of the Fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae).

Fall armyworm (Spodoptera frugiperda) has emerged as a major pest of maize across the Americas, Africa and Asia. Current management relies heavily on synthetic insecticides, which are environmentally unsustainable. However, pheromone-based monitoring, a sustainable and highly promising alternative, often shows variable field efficacy, highlighting the need to identify host plant volatiles that can enhance pheromone-mediated attraction. In this study, we demonstrate that specific maize-derived volatiles play a key role in influencing male behavioral responses. Among the identified compounds, benzaldehyde, myrcene, (Z)-3-hexenyl acetate, nonanal, and ocimene elicited male antennal responses. In laboratory bio-assays, benzaldehyde, (Z)-3-hexenyl acetate, and nonanal induced significantly higher male preference. Field application of ternary pheromone blend consisting of (Z)-9-tetradecenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-11-hexadecenyl acetate at (0.88, 0.01, and 0.11 mg, respectively), supplemented with benzaldehyde and nonanal (0.1 and 0.2 mg, respectively), or nonanal alone at 0.2 mg, significantly enhanced trap captures. In contrast, (Z)-3-hexenyl acetate did not alter trap efficacy, whereas higher doses of either volatile reduced trap captures. These findings provide evidence that host plant volatiles particularly nonanal, and benzaldehyde can synergize with sex pheromone compounds of S. frugiperda, offering a promising strategy to improve semiochemical-based monitoring and integrated pest management.