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. This beetles is now found in at least 10 states. All counties in the lower peninsula of Michigan are under some form of quarantine and isolated infestations of EAB have now been found in Ohio, Ontario, Illinois, Virginia, Indiana, West Virginia, Pennsylvania, Missouri and Maryland . This insect was found in Wisconsin in July of 2008 in northwest Washington and northeast Ozaukee county around the village of Newberg. For current national information on Emerald Ash Borer, go to http://www.emeraldashborer.info
Why the Concern?
Emerald Ash Borer (EAB) is an aggressive wood borer that attacks and kills all species of ash. Although stressed trees are always more prone to borer attack, evidence from Michigan suggests healthy well maintained trees are also killed by this beetle.
What is an Ash Tree?
Ash trees are common yard and woodlot trees found throughout Wisconsin. Ash wood is used in making flooring, baseball bats, tool handles, and cabinets. They are very tolerant of urban environments and have in the past had few serious insect and disease problems. There are four native species of ash; green, white, blue and black ash. Leaves are compound and are attached to opposite sides of a twig. It is estimated there are 717 million ash trees in Wisconsin. For help in indentifying species of ash trees go to the Wisconsin State Herbarium site at:
- http://www.botany.wisc.edu/wisflora/scripts/SearchResults.asp?Genus=Fraxinus
- http://www.botany.wisc.edu/wisflora/scripts/familygeneragallery.asp?Name=Fraxinus&Level=Genus&Gallery=Photo
What is 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 come into the in infested nursery stock or in vehicles on infested firewood. The Wisconsin Department of Agriculture, Trade and Consumer Protection will be conducting a statewide survey of nurseries, searching for signs of this insect.
Contact Jane Cummings-Carlson at the pest lab in Fitchburg, Wisconsin, for an update on Wisconsonsin's approach to control Emerald Ash Borer. You can reach her at 608-275-3273.
Aknowledgements: 
UW Extension, The Wisconsin Department of Natural Resources, The Wisconsin Department of Agriculture, Trade and Consumer Protection along with USDA Animal Plant Inspection Service
Picture Credits: Michigan State University, The Bugwood Network, and the UW-Madison Diagnostic Lab
What Should You Look For
 The Emerald Ash Borer adult is a bright metallic green beetle which is just under a half inch (10-12 mm ) LONG. |
 The damaging stage is the larvae that lives under the bark. |
Potential EAB Look-Alikes
 Blister Beetle |
 Dogbane |
 Ground Beetle |
 Linden Borer |
 Japanese Beetle |
 Tiger Beetle |
 Imported Green Weevil |
 Metallic Wood Borer |
Damage Symptoms to Look For
 Declining ash due to Emerald Ash Borer. |
Initial damage appears as thinning and dieback in the upper canopy of the tree as larvae feed under the bark they damage the conductive tissue. |
How to Distinguish Between Emeral Ash Borer and Other Ash Declines
The are a several symptoms seen in trees attacked by the Emerald Ash Borer.
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Trees will often show dead branches in the top portion of the tree. Excessive amounts of green shoots (suckering) may appear on the lower trunk |
Because there are other problems that cause die-back and death on ash trees, you MUST look further to confirm.
 Look for D-shaped exit holes the adults of the Emerald Ash Borer leave behind in the bark in June and July. |
 Peel bark away look for S-shaped tunnels that snake around under the bark in a serpentine manner. |
Other Insect Problems Associated with Ash
There are other insects that can be found under the bark of ash tress. It is important to be able to identify native insects found in dead and dying trees from the Emerald Ash Borer.
Eastern Ash Bark Beetle is found on dead ash trees. It leaves small round exit holes and the larvae leave distinct galleries that run perpendicular to the wood grain.
 Eastern Ash Bark Beetle |
 Eastern Ash Bark Beetle Galleries |
A number of native species of Agrilus beetles in Wisconsin attack birch, honeylocust, oak, and other trees and shrubs.
 Honeylocust Agrilus adult beetle. |
 Two lined Chestnut borer galleries on oak. |
ASH BORER is a native clear wing moth that can kill smaller trees. It is type of clear wing moth that leaves round pencil sized holes in the trunk. Look for pupal case or exit holes on trunk or larvae in the wood.
 Ash borer pupal case |
 Ash borer larvae |
Other Ash Problems
The most common source of ash dieback and death in Wisconsin is a fungus disease called Verticillium . The fungus clogs the vascular system so the trees have scorched leaves and branch dieback. Tree symptoms look very similar to Emerald Ash Borer but there will be no S-shaped galleries under the bark and no D-shaped exit holes on the trunk.
|
 Ash yellows disease |
Ash Yellows is another disease that causes trees to decline and die over time. For more information on Ash Yellows and Verticllium, go to the Wisconsin Garden facts web site at http://www.uwex.edu/ces/wihort/GardenFacts.html.
Alternative Tree Species to Use
The following are courtesy of Dr. Laura G. Jull, Dept. of Horticulture, University of Wisconsin-Madison and University of Wisconsin-Extension.
Alternatives to Ash for Homeowners
Alternatives to Ash for Professionals
Printable Emerald Ash Borer Information Poster
Who Should You Contact If You Observe or Suspect EAB?
- SEND an insect specimen or damaged wood to the UW Insect Diagnostic Lab, 1630 Linden Drive, Madison, WI 53706.
- If you have a tree that has one of the following symptoms:
- Adult beetle--EAB
- D-shaped exit holes
- S-shaped galleries
- Call 1-800-462-2803 to have someone inspect your trees.
Wisconsin's
Approach | What to Look For | Potential EAB Look-Alikes| Distinguish
Between EAB... | ...Who You Should Contact
Department of Entomology | UW-Madison
URL is http://www.entomology.wisc.edu/emeraldashborer/.
Contact the Insect
Diagnostic Lab with questions about this website.
Page last updated January 16, 2007.