Semiochemical‐mediated oviposition behavior by female peachtree borer, Synanthedon exitiosa

Abstract

AbstractThe peachtree borer, Synanthedon exitiosa (Say) (Lepidoptera: Sesiidae), is an important pest of commercial cultivations of peach trees, Prunus persicae (L.) (Rosaceae). Identification of semiochemicals that mediate host selection by adult S. exitiosa may lead to the development of a new earth‐friendly tactic within integrated programs for control of S. exitiosa. Larvae develop in the phloem of peach trees where their feeding stimulates the production of gum frass, a mixture of tree phloem particles, tree sap (gum), and larval feces (frass). We tested the hypothesis that gum‐frass semiochemicals signal a potential host tree, and induce oviposition by female S. exitiosa. In coupled gas chromatographic‐electroantennographic detection analyses of Porapak Q‐collected gum frass volatiles, 21 compounds elicited responses from male or female S. exitiosa antennae. These compounds included four acids, four hydrocarbons, four ketones, three acetates, two aldehydes, γ‐decalactone, conophthorin, 2‐phenylethanol, and 2‐isopropyl‐3‐methoxypyrazine. In dual‐choice laboratory experiments, all groups of compounds, except the acetates, were needed to induce significantly more egg laying by female S. exitiosa on treatment than on unbaited control oviposition sites. By responding to gum frass semiochemicals, female S. exitiosa seem to exploit signals that are complex, detectable, and that reliably indicate a potential host tree for larval development.