The Emerald Ash Borer (EAB), Agrilus planipennis Fairmaire, has been detected, collected, and blamed for killing thousands of ash trees (Fraxinus pennsylvanica, F. americana, and F. nigra) in the Southeastern region of Michigan. This is the first report of EAB in North America. Surveys have found EAB in five Michigan counties (a 70 X 70 mile radius). Michigan Dept. of Agriculture has placed a quarantine on movement of ash trees and lumber for this area. EAB is believed to have been established in Michigan for the past four years. Shortly after the Michigan detections in July of this year, the EAB was also detected in Essex County Ontario.
In Michigan the borer has only been associated with ash trees. It typically attacks dead or dying trees but can attack healthy tree specimens. Based on its native Asian habitat the EAB prefers typical temperate to warm temperate climate zones. The likely modes of EAB introduction are unseasoned sawn timber, dunnage, and wooden crates with bark.
Damage to ash trees is extensive and lethal. Dieback of the uppermost tree portions is usually followed by decline of the entire tree in the following year. Diagnostic symptoms and insect descriptions are available at http://www.msue.msu.edu/reg_se/roberts/ash/index.html.