Electroantennographic and field responses of <i>Hyphantria cunea</i> (Drury) to synthetic sex pheromone components

The <i>Hyphantria cunea</i> (Drury) is a highly polyphagous invasive pest that has become widespread and destructive in China. Although sex pheromone components of <i>H. cunea</i> have been identified, the weak field attraction of synthetic sex pheromone has hindered the application of sex pheromone-based lures in efficient monitoring and management of this pest. In this study, the electroantennographic (EAG) and field responses of <i>H. cunea</i> male adults to three synthetic sex pheromone components, including Z9, Z12, Z15-18Ald (C18:Ald), Z3, Z6-9S,10 R-epoxy-21Hy (C21-2Epo), and 1, Z3, Z6-9S,10 R-epoxy-21Hy (C21-3Epo), were evaluated. Male antennae exhibited significant dose-dependent response to three individual components and a ternary mixtures. The younger and virgin male moths showed stronger electrophysiological activity to synthetic compounds, whereas sensitivity decreased significantly after mating. Among the three components, C21-3Epo elicited the strongest antennal responses. Field trapping revealed that neither single compounds nor binary blends attracted males, whereas only the ternary blend of C18:3Ald, C21-2Epo, and C21-3Epo (ratio 8:1:1; 10 mg total load) effectively captured large numbers of males. In addition, the field trapping indicated that the green rubber septum functioned as a practical dispenser for synthetic pheromones. The Unitraps baited with the green rubber septum showed significantly higher trapping efficiency than cotton wicks, highlighting the septum as a promising dispenser for field deployment of synthetic sex pheromones. Finally, the green rubber septum baited with a ternary blend monitored the dynamics of <i>H. cunea</i> occurrence and detected that the emergence period overlapped with the commercially available synthetic lure. In general, the bioactivity of the synthetic sex pheromone of <i>H. cunea</i> was validated. It could effectively capture <i>H. cunea</i> male adults, be used to monitor and control <i>H. cunea</i>, and further be incorporated into the integrated pest management programme.