From the Walnut Council Maryland Chapter Newsletter

From the Walnut Council Maryland Chapter Newsletter, Fall 2003, Volume 10, Issue 2

Emerald Ash Borer Comes to Maryland

Emerald Ash Borer is a newly introduced invasive exotic (Asian) pest that is wreaking havoc in southeast Michigan, where it was first found two years ago. It reportedly attacks and kills all ash trees regardless of species or size in the infested area. While this insect does not threaten walnut trees, ash trees are commonly found or planted along with walnut trees, and are an economically and ecologically important part of our forests and landscapes. The following information is from a fact sheet produced by the Maryland Department of Agriculture on September 2nd, 2003.

Emerald Ash Borer Discovered in Maryland:

On Thursday, August 28, a Maryland Department of Agriculture (MDA) nursery inspector found emerald ash borer-infested trees at a single Prince George's County nursery.
On Friday, August 29, the U.S. Department of Agriculture (USDA) Systematic Entomology Laboratory in Beltsville, MD confirmed the identification of the emerald ash borer.
Emerald ash borer (EAB) is a serious pest of quarantine significance. To date, the emerald ash borer has only been detected in the U.S. in 13 counties in Michigan (2002) and one county in Ohio (February 2003). Maryland is now the third state with a detection.
Nursery records and regulatory investigation by MDA and USDA indicate that the nursery received 121 ash trees in two shipments (57 ash trees on April 2 and 64 ash trees on April 3).
This is an isolated incident. There are no other ash tree shipments into Maryland that are suspect for emerald ash borer.
All of the 121 trees are accounted for (93 have already been destroyed and the MDA has one in its laboratory). MDA is inspecting sites where the remaining 27 trees were planted.
MDA will perform a delimiting survey with 1/2 mile radius from each of the known sites where infested ash trees are located to define the possible spread of the insect, if any, to other ash trees.
MDA will likely issue a state quarantine to restrict movement of ash trees from affected areas, once the affected areas are determined.
It appears that this past spring, there was adult emergence of the emerald ash borer from the ash trees shipped into Maryland. The adult females laid eggs, and the signs of the larval feeding are appearing now. They will stay in the larval stage through winter, will transform into adults next spring, then emerge from the tree, fly and mate. There will likely be only one generation per year.

How Can I Identify the Emerald Ash Borer?

The emerald ash borer is an exotic wood boring beetle discovered and identified in southeast Michigan in the summer of 2002, and then in Ohio in February 2003. It is originally from Asia.
Adults are dark metallic green in color, 1/2 inch in length, and 1/16 inch wide, and are present only from mid-May until early August. Larvae are creamy white in color and are found under the bark.
Affected trees show symptoms of infestation including: die-back on the upper third of the tree, D-shaped exit holes in the bark where adults emerge, vertical splits in the bark, and distinct serpentine-shaped tunnels beneath the bark in the cambium, where larvae effectively stop food and water movement in the tree, starving it to death. It takes 1-3 years for the infested tree to die.

How Will This Impact Maryland?

If not eradicated, the emerald ash borer could have a very serious negative economic and environmental impact.
The greenhouse and nursery industry is the second largest agricultural industry in Maryland. It accounts for $303.8 million in cash receipts. (Maryland Agricultural Statistics Service, Farm Receipts in 2002)
Ash trees are one of the most common landscaping trees used in the U.S. and are common in western Maryland forests.
Ash wood is used for all traditional applications of hardwood, from flooring and cabinets to baseball bats.