Ethanol-injection induces attacks by ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) on a variety of tree species

Exotic ambrosia beetles have become serious pests in ornamental tree nurseries. However, research on their biology, ecology and behaviour to develop management tactics is hampered by the lack of reliable attacks on experimental trees. Injecting Magnolia virginiana L. with ethanol consistently induced attacks by exotic ambrosia beetles to facilitate research on their biology and management. The ability to attract ambrosia beetles to trap trees may be useful for developing nonchemical strategies and techniques for managing them in nurseries. However, to be useful in management techniques, ethanol-injection has to reliably induce attacks on a vlariety of tree species. Experiments were conducted in Ohio, Tennessee and Virginia, where ethanol-injection was tested on 16 species of deciduous trees from 11 families. Ethanol-injection reliably induced attacks by exotic ambrosia beetles on all tree species tested. There were differences in the numbers of attacks by ambrosia beetles among species of trees in most experiments, although no species was identified consistently as the most or least attacked in repeated experiments. The positive association of attacks with ethanol concentrations in bark tissue indicate that the attack rates were most likely related to the uptake and emission of ethanol. The results of the present study indicate that ethanol-injection reliably induces ambrosia beetle attacks on a wide range of deciduous tree species, which should further facilitate research on ambrosia beetles in nurseries and the development of behaviour-based management tactics that divert ambrosia beetles away from ornamental trees.