Host preference of Agrilus planipennis (Coleoptera: Buprestidae) in Southeast Michigan: Fraxinus quadrangulata - Hope for a genus in North America

Emerald ash borer (Agrilus planipennis, Coleoptera: Buprestidae) was first identified near Detroit, Michigan in 2002. In its native range, EAB is considered a secondary pest, typically attacking only declining or stressed Fraxinus trees. In North America, EAB host preference or the ability of trees to resist EAB varies among ash species. Fraxinus pennsylvanica is usually colonized at higher densities than F. americana when they co-occur while larval density is often higher on F. americana than on F. quadrangulata. Fraxinus quadrangulata appears to be the least susceptible N. American ash species, but it too comes under attack when other nearby ash hosts have been depleted. In field observations, EAB preferentially colonize ash in the following order: F. nigra, F. pennsylvanica, F. americana, and F. quadrangulata, but the reasons governing preference need further investigation. The purpose of this study is to examine wooded sites in Southeast Michigan to determine EAB host preference between F. americana and F. quadrangulata.