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Emerald Ash Borer
Emerald Ash Borer (Agrilus planipennis) is an exotic wood boring beetle that only feeds on ash trees.  The metallic green beetle is native to Asia and was first discovered near Detroit, Michigan in 2002.  Since then the beetle has been identified in Windsor, Ontario,Canada; Indiana, Ohio, Illinois, Pennsylvania, West Virginia, Maryland, Virginia, most recently in Missouri and now, Wisconsin.

NEW! EAB found in southeast Wisconsin, August 2008

NEW! EAB Detected in Washington County; Quarantine Now in Effect

EAB is not a threat to human health but it does threaten our tree population both in our forests and in our urban areas.

What is the concern?
EAB is 100 percent fatal to ash trees of any size, any age, healthy or unhealthy. The adult beetles nibble on the foliage of ash trees but cause little damage.

The larvae (the immature stage of EAB) cause the most harm by feeding on the inner bark of ash trees.  This disrupts the trees’ ability to transport water and nutrients, causing the tree to starve and eventually die.

A tree that has been attacked by EAB can die within 2-4 years.  It is estimated that more than 15 million ash trees are dead or dying in the Midwest because of this insect.

Wisconsin forests contain more than 737 million ash trees, nearly 7 percent of the tree population. In urban areas, we estimate that ash make up 20 percent of the urban street trees.

After the larvae grow into adult beetles, they burrow through the tree bark to the outside, leaving behind tiny D-shaped exit holes. 

Emerald Ash Borer Life Cycle

• May to August: Eggs hatch into larvae and tunnel into ash trees
• August to October: Larvae feed under tree bark, creating S-shaped galleries
• October to May: Larvae over winter under tree bark
• May to June: Adults emerge leaving D-shaped exit holes; some adults have been seen into August; adults live about three weeks
• Mid-May to Mid-August: adults mate then lay eggs in ash bark

For more information, contact 1-800-462-2803 or send an email.