Plant Volatiles Enhance Behavioral Responses of Grapevine Moth Males, <i>Lobesia botrana</i> to Sex Pheromone

Plant volatiles play an important role in the lives of phytophagous insects, by guiding them to oviposition, feeding and mating sites. We tested the effects of different host-plant volatiles on attraction of <i>Lobesia botrana</i> males to the female-produced sex pheromone, in a wind tunnel. Addition of volatile emissions from grapevines or individual plant volatiles to pheromone increased the behavioural responses of <i>L. botrana</i> males over those to pheromone alone. At a low release rate (under-dosed) of pheromone, addition of (<i>E</i>)-β-caryophyllene, (<i>Z</i>)-3-hexenyl acetate, 1-hexanol, or 1-octen-3-ol increased all behavioral responses, from activation to pheromone source contact, while addition of (<i>E</i>)-4,8-dimethyl-1,3,7-nonatriene, (<i>E</i>)-β-farnesene, (<i>Z</i>)-3-hexenol, or methyl salicylate affected only the initial behavioural responses. Dose–response experiments suggested an optimal release ratio of 1:1000 (sex pheromone: host plant volatile). Our results highlight the role of plant volatiles in the sensory ecology of <i>L. botrana</i>.