Abstract
Since its accidental introduction to the United States in 2002, the Emerald Ash Borer (Agrilus planipennis, EAB), has spread across the country and devastated American ash tree (Fraxinus spp.) populations. The ash trees remaining in invaded forests now generally fall into two categories, lingering ash, the ash trees that have survived EAB infestation, and dead or dying ash. One potential mechanism for resistance to EAB is the production of foliar phytochemicals, such as phenol compounds. To determine if lingering and susceptible ash trees differ in foliar phytochemical production, I sampled 60 ash trees from three different sites in Michigan and measured the concentration of total phenolics in their leaf tissue. While total phenolic concentration in susceptible ash trees was slightly higher, this difference was not significant. There was, however, a difference in mean phenol concentration between two of the sites, suggesting that site conditions may affect production of phenolic compounds. The trend of slightly higher concentrations of phenols in susceptible trees suggests that if phenolics are used for defense, it may be an inducible defense.