New pest
Emerald Ash Borer in Virginia
Va Tech, Department of Entomology

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Introduction: 

The emerald ash borer, Agrilis planipennis, is a destructive pest of ash and has killed millions of trees in Michigan, Ohio, Indiana, Illinois, Pennsylavania, West Virginia, and Maryland.  It is also found in Canada.  Although eradicated in Virginia in 2004, it has been found again in the Commonwealth in 2008.  This borer is from Asia and was found in SE Michigan in 2002 and has spread from the original site near Detroit.  Native ash trees in North America have no apparent resistance to this borer and trees die 3-4 years after initial infestation.

How to determine if you have Emerald Ash Borer:

Make sure that you have an ash tree


Signs of damage


Look for D-shaped exit holes


Look for woodpecker damage


If you can peel off bark, look for S-shaped mines


Appearance


Identification:

Adult beetles are about 1/2 to 3/4 inch long and have a bright green metallic coloration. The larvae are up to 2 inches long and have a pincher-like appendage at the end.  The larvae also have lobes on the side of body.

Life Cycle:

Adult beetles emerge in late May, June, and July and feed on the leaves before laying eggs on the bark in crevices.  Eggs hatch in about a week and the immature stage immediatly borers into the bark and begins feeding in the cambium area just under the bark.  The larvae make long S-shaped tunnels.  They feed until fall and then spend the winter under the bark. They pupate in the spring and the adults emerge from D-shaped exit holes.

Damage:  Tunneling by the larva cause cause girdling and death of branches and the trunk. Dieback starts on the top of the tree and progress down. Often the tree will produce shoots at the base as a responce to the top dying out.

Control:

Note that controls must be applied before the ash tree shows signs of damage.

Homeowner


Professional Landscapers and Arborists


Comments

Although the emerald ash borer is only known from Fairfax County, it is possible for it to show up in other locations in Virginia.  Submit any suspect beetles to your local extension office.

Prepared by Eric Day, 07/10/08