Tree girdling and host tree volatiles provides a useful trap for bronze birch borer Agrilus anxius Gory (Coleoptera: Buprestidae)†

The bronze birch borer, Agrilus anxius, is a North American buprestid pest of stressed or weakened birch trees (Betula spp.) and is considered a major threat to European birch species as a potentially adventive insect. Laboratory bioassays and field trapping experiments were conducted to elucidate potential visual and chemical cues used in host location in this species. Birch bark and foliar volatiles (Betula papyrifera Marsh) and a pheromone attractive to the congener, A. planipennis, (3Z)-dodecen-12-olide ((3Z)-lactone), were tested along with a girdled tree treatment, with purple sticky prism traps. Only the girdled tree treatment with purple traps elicited significant attraction by adult A. anxius. Various colours of sticky traps were tested with host volatiles attractive to A. planipennis; results showed that unbaited green sticky traps were more attractive than other colours tested; none of the host volatiles tested increased trap capture with any traps. Examination of foliage and bark of B. papyrifera by GC/EAD, and GC/MS techniques has identified several EAD-active compounds with (3Z)-hexenol and (5 S,7 S)-conophthorin as the most EAD-active molecules. Neither compound, however, alone or combined, elicited significant trap capture on green sticky prism traps; these compounds may find importance as synergists once the pheromone for A. anxius is identified.