Emerald Ash Borer

The Emerald ash borer (Agrilus planipennis), an invasive, wood-boring beetle that attacks ash trees, was positively identified for the first time in Wisconsin in August 2008. The beetle and beetle larvae were found at a private home in Ozaukee County, Wisconsin.

This exotic insect is native to Asia and is currently killing ash trees (Fraxinus spp.) in the Great Lakes region at an alarming rate. Since its initial discovery in southeastern Michigan in 2002, the emerald ash borer has spread throughout Michigan's entire Lower Peninsula and into the easternmost areas of the Upper Peninsula as well as into nearby Ohio, Indiana and Ontario, Canada. Infestations have also been confirmed in numerous suburban Chicago locations in Illinois, as well as isolated infestations in Pennsylvania, West Virginia, Maryland, and now, Wisconsin. An estimated 25 million ash trees have been killed by emerald ash borer in these infested areas.

Emerald Ash Borer is Spreading

This is a slow moving insect, except when it gets help from us. The insect's natural dispersal rate is just one-half to two miles annually; however, its transmission has accelerated due to the inadvertent transportation of emerald ash borer larvae in infested materials by people. Scientists at Michigan State University have concluded through increment core analysis that the emerald ash borer was present in southeastern Michigan as far back as the early 1990’s, at least 10 years prior to its discovery in the area. Therefore, there is a strong possibility that the emerald ash borer has been residing in Wisconsin for some time, despite the fact that it was not found until recently.

Emerald Ash Borer's Effects

The emerald ash borer belongs to a group of insects known as metallic wood-boring beetles (Buprestidae). The beetle's immature or larval form spends its life feeding beneath the bark of ash trees. As a result, the ash tree host suffers extensive damage to its vascular system, depriving the tree's crown of water and nutrients. Research conducted by Michigan State University and the USDA Forest Service has shown the emerald ash borer attacks both stressed and healthy ash trees, typically killing its host in three to five years. All ash species in Wisconsin are attacked, including white, green black and blue ash. Mountain ash (Sorbus spp.), not a true ash, is unaffected.

We Need Your Help

Forest inventory and analysis data shows that Wisconsin's forests include approximately 727 million ash trees. As a component of our northern hardwood, oak-hickory and bottomland hardwood forests, ash trees are a valuable Wisconsin resource. In addition, an estimated 5.2 million ash trees are planted throughout the urban landscape. The potential destruction that emerald ash borer could bring to Wisconsin is unfathomable. As of August 2008, the emerald ash borer has only been found in one location in our state, but it may be present elsewhere. Early detection and isolation of infestations are our best defenses against the ecological and economic damage caused by emerald ash borer. The development of the Wisconsin Emerald Ash Borer Response Plan [PDF, 350KB] has recently been completed and the development of the more comprehensive strategic plan for emerald ash borer program activities is currently underway by the State of Wisconsin emerald ash borer Advisory Group. The Advisory Group is a collaborative effort between the Wisconsin Department of Natural Resources (WI DNR), Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), University of Wisconsin, UW-Extension, USDA-APHIS and USDA-Forest Service. Despite this large interagency effort fronting the fight against emerald ash borer, we still need your help looking for emerald ash borer due to the elusive behavior of this pest!

Please review the information on EAB signs and symptoms, other pests and diseases and EAB look-alikes on this website. After that, if you still suspect an emerald ash borer, please report it immediately by calling the emerald ash borer hotline at 1-800-462-2803.