Be aware of emerald ash borer

ST. PAUL, Minn. (5/15/2007) - The week of May 20-26, 2007, has been designated Emerald Ash Borer Awareness Week in Minnesota, another reminder that we should keep an eye out for this very destructive pest which can kill ash trees within three years.

No ash is safe from this insect. All species are attacked, including green, black and white ash. Emerald ash borer attacks all sizes of trees from one-inch diameter to large, mature ash.

Experts estimate that this destructive beetle has already killed more than 20 million ash trees, most of them in southeast Michigan. This exotic borer, native to northern China and Korea, was first found in North America in southeast Michigan in June 2002. It has since spread to Ontario, Ohio, Indiana, Maryland, and as of last summer, Illinois.

On its own, emerald ash borer will only move about one-half mile a year from infested sites. But with help from people, it can travel hundreds of miles when carried in firewood and other wood products or nursery stock. It's because of humankind's activities that emerald ash borer could have been inadvertently brought into Minnesota last month.

In late April, inspectors discovered that firewood distributed by Taylors Wood Products had been brought inappropriately from Illinois into Minnesota and sold at various Menards stores. Ash wood can't be moved from quarantine areas unless it has been treated or the bark has been removed (emerald ash borer lives under the bark until it turns into an adult beetle). However, this firewood was brought into Minnesota with the bark intact, and some was sold before this was discovered. People who purchased Taylors wood were asked to burn it by May 4. Unsold firewood has since been removed and returned to Taylors Wood Products.

Nobody knows whether any emerald ash borers were actually brought into the state in this wood. However, Minnesota risks a lot when this insect gets here. There are about 870 million ash trees in Minnesota, one of the largest concentrations of ash in any state in the country. Not only is this type of tree abundant in our forests, but it is also an important component of our urban landscapes. This insect will get here eventually, but the longer we can forestall its entry to Minnesota the better chance we will have of adequately dealing with it when it does arrive.

What can people do to help? First, don't transport firewood when you go camping, even if it's within Minnesota. Just buy the wood you need at a local site at the campgrounds.

Also, be alert to what an emerald ash borer looks like. It's about one-third to one-half inch long, somewhat bullet-shaped and iridescent green. Keep in mind that there are some common insects that look similar, such as sixspotted tiger beetles and Polydrusus weevils.

Also be aware of the symptoms of an emerald ash borer infested tree. Noticeable damage starts with thinning foliage and dieback in the crown. Epicormic sprouts, or sprouts that emerge from dormant buds, may also form on the trunk and some major branches. You may see vertical splits in the bark, due to callus tissue forming over old galleries. If you remove bark on the trunk, you may find larval galleries, a series of criscrossing tunnels.

If you see an insect in Minnesota that you think may be an emerald ash borer, or you find an ash tree that has suddenly started to decline and die and you suspect borers, contact the Minnesota Department of Agriculture on their Arrest the Pests Hotline at (651) 201-MOTH (6684) or 1-888-545-MOTH (6684).

For more information about emerald ash borer, visit the MDA website, http://www.mda.state.mn.us/plants/pestmanagement/eab.htm.

Media Contact: Julie Christensen, U of M Extension, (612) 626-4077, reuve007@umn.edu

NOTE: News releases were current as of the date of issue. If you have a question on older releases, use the news release search (upper left-hand column of the News main page) or the main Extension search (upper right of this page) to locate more recent information.

URL: http:// www.extension.umn.edu/extensionnews/2005/emeraldashborer07.html  This page was updated May 15, 2007 .
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