Olfactory Response of Plutella xylostella Adults to Volatile Compounds of Brassica Hosts Under Laboratory Conditions

Abstract

Olfactory-mediated host selection behavior of Plutella xylostella adults was evaluated under laboratory conditions to determine their responses to volatile organic compounds emitted by different Brassica host plants. Adult moths were exposed to plant-derived volatiles using a dual-choice olfactometer assay, and behavioral attraction or repellence was recorded under controlled environmental parameters. Volatile profiles of selected Brassica species were analyzed to identify key chemical cues influencing insect orientation. Results demonstrated significant variation in adult attraction among different host volatiles, indicating selective olfactory sensitivity to specific glucosinolate-derived and green leaf volatile compounds. Brassica oleracea cultivars exhibited stronger attractiveness compared to other tested hosts, likely due to higher emission of isothiocyanates and aldehydes known to mediate host recognition. Behavioral assays confirmed that female moths showed higher responsiveness than males, suggesting reproductive host-seeking behavior linked to oviposition site selection. The study also revealed that synthetic blends mimicking host volatile signatures successfully replicated attraction responses, reinforcing the role of specific chemical compounds in host-finding mechanisms. These findings highlight the importance of semiochemical cues in regulating P. xylostella host location behavior and provide insights into plant–insect chemical interactions. Understanding olfactory response patterns can support the development of pheromone- and kairomone-based pest management strategies, including trap-based monitoring and behavioral disruption techniques for sustainable control of diamondback moth populations in Brassica cultivation systems.