Welcome to the UW-Madison Emerald Ash Borer Information Page

The Emerald Ash Borer (Agrilus planipennis) was discovered in Michigan in June 2002. It is a species of metallic wood boring beetle (Buprestidae) that attacks ash (Fraxinus), usually killing trees in one-three years, when beetle populations are high.  When beetle populations are low (i.e., a new infestation) it can take 5 or more years for trees to die.

This beetle has been found in 24 states and two Canadian Provinces (map).  The bulk of the Federal quarantine extends from southern Wisconsin, Iowa and Missouri east to Virginia, Pennsylvania, and New York.  Infestations have been confirmed in Arkansas, Colorado, Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Wisconsin.  This insect was found in southeast Wisconsin in July of 2008, southwest Wisconsin in April of 2009, and was detected in Brown County (Green Bay area) in July 2009.  Since then, infestations have been discovered throughout much of southern Wisconsin.

Currently, 37 Wisconsin counties have been quarantined for EAB: Adams, Brown, Buffalo, Calumet, Columbia, Crawford, Dane, Dodge, Door, Douglas, Fond du Lac, Grant, Green, Iowa, Jefferson, Juneau, Kenosha, Kewaunee, La Crosse, Lafayette, Manitowoc, Milwaukee, Monroe, Oneida, Outagamie, Ozaukee, Racine, Richland, Rock, Sauk, Sheboygan, Trempealeau, Vernon, Walworth, Washington, Waukesha, and Winnebago counties.  A list of municipalities (by county) with known EAB infestations can be found here. The biggest news in 2014 has been the detection of EAB in Adams, Buffalo, Calumet, Columbia, Door, Grant, Monroe, and Oneida Counties.  Due to the proximity to known finds, several other counties in the state have also recently been quarantined, but do not yet have confirmed EAB detections: Green, Iowa, Kewaunee, Lafayette, Manitowoc, Outagamie and Richland counties.  For the most recent information on the current EAB quarantines in Wisconsin, visit the WIsconsin DATCP EAB website.

October 2014 EAB Map

Why the Concern?

Emerald Ash Borer (EAB) is an aggressive wood borer that attacks and kills all species of ash.  Ash wood is used in making flooring, baseball bats, tool handles, and cabinets.  It is estimated that there are well over 700 million ash trees in Wisconsin.  Although stressed trees are always more prone to borer attack, evidence from Michigan suggests that healthy, well maintained trees are also attacked and killed by this beetle.

Wisconsin’s Approach

The main defense in Wisconsin is to identify and destroy infestations before they can become widespread. The most likely source of problems is infested firewood that has been brought into the state from infested areas. For this reason, the Department of Natural Resouces is conducting a statewide survey of state forests and parks, specifically looking for signs of this insect.  The insect can also be transported in infested nursery stock. The Wisconsin Department of Agriculture, Trade and Consumer Protection will be conducting a statewide survey of nurseries, searching for signs of this insect.  The Wisconsin Department of Agriculture, Trade and Consumer Protection also conducts trapping efforts using prism traps.