Tree affected by Emerld Ash Borer Tree affected by Emerld Ash Borer Tree affected by Emerld Ash Borer

Research on Emerald Ash Borer


The emerald ash borer (Agrilus planipennis, EAB) is a tree boring beetle native to Asia which was inadvertently introduced to the United States during the 1990’s and has been implicated in the widespread decline of ash trees across the Midwestern US. Ash trees are widely dispersed across the US and represent the only known host in the introduced range. Lacking a full suite of natural enemies in its introduced range, EAB has spread from its introduction epicenter near Detroit, MI to 18 states in just over a decade. EAB larvae damage the cambial tissue of ash trees resulting in rapid tree mortality. The widespread distribution of ash trees in the US paired with the rapid and extensive tree mortality induced by this disturbance represents a major threat to forest ecosystems with potentially cascading effects on other ecosystem processes.

Research Objectives

My EAB research occurs at multiple scales from the tree-level to the ecosystem. In an effort to understand how EAB impact ash trees, we utilized a previously developed visually classification scheme and destructively harvested ash trees to develop a relationship between canopy decline symptoms, EAB (larval gallery cover and adult/larval density), and foliar δ13C (a proxy for leaf level water stress) (see Flower et al. 2013 FEM). Furthermore, we have paired canopy decline symptoms with physiological measurements to understand how EAB alters tree water use and tree carbon allocation (submitted). We have also initiated a forest level experiment to investigate ecosystem responses to EAB. In this experiment we have three treatments, a control treatment where ash trees are allowed to naturally senesce, a girdling treatment in which we mechanically remove phloem tissue, and an insecticide treatment in which we inject the ash trees with a chemical to inhibit EAB larval feeding. Finally, in conjunction with the USDA Forest Service, we have been monitoring permanent and experimental research plots across Ohio to assess the impacts of EAB on forests (see Flower et al. 2013 Biological Invasions). Interested in collaborating, feel free to contact me at cflowe3 (at)