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Emerald Ash Borer

Adult beetles with varying colors

Adult beetle size
Facts & History of Emerald Ash Borer (EAB):

EAB is an exotic, destructive, phloem feeding beetle from Asia, specifically eastern Russia, northern China, Japan and Korea. It was first discovered in southeastern Michigan and adjacent areas in Windsor, Ontario, Canada in 2002. It is thought to been introduced to North America in the 1990's on solid wood packing material originating in Asia. By June 2006, EAB had been found in Michigan, Indiana, Ohio, Illinois (50 miles from WI border), and Ontario, Canada.

EAB has been found in 37 counties in Wisconsin, cities include; Lacrosse, Green Bay, Milwaukee, Lake Geneva, Superior and several other Wisconsin communities including the Upper Peninsula of Michigan. Infestations were found in Madison in November 2013.

As of April 2015, EAB can also be found in 25 other states including; Michigan, Indiana, Ohio, Illinois, Iowa, Minnesota, Kansas, Kentucky, Maryland, Massachusetts, Missouri, New York, Pennsylvania, Tennessee, Virginia, West Virginia, Colorado, Connecticut, Georgia, New Hampshire, North Carolina, Arkansas, Louisiana, New, Jersey.


References & more Information


Healthy white-ash tree
What trees are susceptible to the EAB?

Infested trees in a park in Michigan

All sizes and even very healthy ash trees can be killed by the Emerald Ash Borer. Ash species attacked by emerald ash borer include green (Fraxinus pennsylvanica), white (F. americana), black (F. nigra), and blue (F. quadrangulata), as well as horticultural cultivars of these species. Green and white ash are the most commonly found ash species in the Midwest with blue ash being rare.

While other woody plants, such as mountain ash and prickly ash, have "ash" in their name, they are not true ash, or Fraxinus species. Only true ash are susceptible to attack by emerald ash borer.

How does EAB harm trees?

EAB damage

Life cycle

Layers of a tree

EAB larva

The larva (the immature stage of EAB) spends its life inside ash trees, feeding on the spongy layer of tissue just beneath the bark. This feeding destroys that tissue and stops the trees' ability to move water and nutrients back and forth from the roots to the rest of the tree. The tree starves and eventually dies.

References & more Information

Infested firewood
(note larvae tunnels)
How does EAB spread?

EAB moves short distances (½ mile annually) by flying and can survive longer distances in transit on ash nursery stock, ash logs, branches and firewood. Everyone, whether a Wisconsin Resident or non-Resident, is being asked to buy firewood inside or near the property where you plan to camp, burn all of the wood you purchase or leave it behind for another camper, and do not move firewood around with you on your camping trip.

References & more Information

How important are ash trees to Madison and Wisconsin?

There are approximately 770 million ash trees in Wisconsin's forests. About 30% of Wisconsin's and approximately 24% of Madison's street trees are ash. Madison's Street Tree Map of about 95,000 street trees contains around 21,700 ash trees. Many thousands of ash trees also live in parks, greenways, and on private property.

The ash species was heavily planted in Madison after Dutch Elm Disease swept through the city in the 1960's and 70's. Ash was popular within urban areas because they could withstand all urban types of conditions such as clay soils, road salt accumulation, and air pollution. Many varieties of ash such as 'Marshall Seedless' green ash and 'Autumn Purple' ash originated at the UW Madison. The loss of these trees would be devastating to many communities and prohibitively expensive to remove and replace. Ash serves as an important species in Wisconsin's northern and southern forests and is a key component of forests growing in wet areas including swamps and along river ways.

City Pre-Qualified Tree Contractors Any services on any city tree requires a permit issued by Forestry: City Pre-Qualified Contractors.
Wisconsin Department of Natural Resources, Michigan State University Extension, Ohio Department of Agriculture, U.S. Forest Service, Illinois Department of Agriculture.

Photo Credits Lexa Panessidi, State of Michigan, Minnesota Department of Natural Resources Archives, David Cappaert, Paul Wray, Iowa State University, Troy Kimoto, Canadian Food Inspection Agency