Tricounty News

Emerald Ash Borer is in Minnesota: Now What?

The Emerald Ash Borer (EAB) is in Minnesota! On May 14 the Minnesota Department of Agriculture confirmed the discovery of an emerald ash borer infestation in the St. Paul area. It is estimated that the EAB may have been active in this area four or five years before its discovery. Our efforts now must change from keeping this destructive pest out of Minnesota to keeping it contained in the area where it has been found.

A quarantine has been issued that restricts the movement of firewood, ash nursery stock, ash logs and branches, uncomposted wood chips or any other article that could spread EAB in Ramsey and Hennepin counties. A similar quarantine had been issued in Houston County due to its proximity to the site where the EAB was found in western Wisconsin.

Minnesotans should be greatly concerned about EAB. Minnesota has one of the largest concentrations of ash in the U.S. with about 900 million found in our forests and urban landscapes. This insect attacks all species of ash, regardless of size or state of health. The trees are killed after 3 to 5 years of the larvae tunneling and feeding under the bark.

We must now concentrate on slowing the EAB's spread.  Firewood is the primary method EAB has for being moved long distances. By itself it only flies about 1/2 mile a year, but with people's help it can travel hundreds of miles at a time. Don't transport firewood, even within Minnesota. Don't bring firewood along on a camping trip. Purchase the wood you need from an approved vendor and don't bring extra wood home with you. Likewise, do not purchase fireplace or furnace firewood from a vendor outside your area.

We must be vigilant so we can detect the presence of the EAB before it has had time to become established.  Become aware of the identifying characteristics of emerald ash borer and the symptoms of an EAB-infested ash tree.  An emerald ash borer is a slender, slightly tapered, bright metallic green beetle about 1/2 inch long.  It is active anytime from late May into August. There are other green beetles and other insects in Minnesota so look closely.

University of Minnesota Extension Web site:

Be alert to trees that are suddenly showing signs of thinning foliage and dead limbs. Some ash trees are showing decline because of environmental stress and disease, but canopy dieback is a definite signal to look for additional signs. An emerald ash borer-infested tree will show signs of D-shaped exit holes about 1/8 inch long. If you were able to look under the bark, you would find a series of S-shaped tunnels packed with frass, a mixture of sawdust and excrement. You may also see increased woodpecker activity as they feed on the EAB larvae and pupae.

If you suspect that your ash tree could be infested by EAB, go to, and use the "Do I Have Emerald Ash Borer?" checklist. You can also contact the Minnesota Department of Agriculture on their Arrest the Pest Hotline at (651) 201-6684 or (888) 545-6684.

Information gained from articles by Jeffrey Hahn, University of Minnesota Assistant Entomologist, and Michael Schommer, Minnesota Department of Agriculture Communications, was used in preparing this news release.