Semiochemical attractants for the beech leaf‐mining weevil,Orchestes fagi

Abstract

AbstractThe beech leaf‐mining weevil,Orchestes fagiL. (Curculionidae:Curculioninae:Rhamphini), a pest of European beech,Fagus sylvaticaL. (Fagaceae), was recently discovered infesting American beech,Fagus grandifoliaEhrh., in Nova Scotia, Canada. AdultO. fagifeed on both young and mature leaves of beech as well as on other species (e.g., raspberry,Rubusspp.), but oviposition and larval feeding are restricted to beech. Females oviposit in young developing beech leaves at the time of bud burst. We characterized volatiles emitted from buds, leaves, and sapwood of American beech and examined their potential as attractants alone or when combined with other weevil pheromones forO. fagi. We predicted that adults would be attracted to volatiles emitted from beech leaves, especially those emitted from bursting beech buds. Gas chromatography/mass spectrometry (GC/MS) analyses of volatiles collected from buds at pre‐ and post‐budburst identified two diterpene hydrocarbons, 9‐geranyl‐p‐cymene (1) and 9‐geranyl‐α‐terpinene (2a), that were emitted in large amounts at the time of bud burst. Compound1significantly increased mean catch of males and totalO. fagi(but not females) on sticky traps compared with unbaited controls. Y‐tube bioassays confirmed attraction of maleO. fagito bursting beech buds and compound1. Attraction of maleO. fagito1, emitted in large quantities from American beech, is likely adaptive because both oviposition and mating ofO. fagicoincide with budburst. Our data suggest that traps baited with1may be useful for monitoring the spread ofO. fagiin North America.