MnDOT to remove emerald ash borer infested trees

Published 9:51 am Monday, August 25, 2014

The Minnesota Department of Transportation and Minnesota Department of Agriculture inspected a confirmed emerald ash borer infestation near U.S. Highway 63 and are making plans for the removal and disposal of the trees.

The site south of Rochester is near Interstate 90 and Highway 63 in MnDOT right of way. Samples were taken Thursday that will be processed to help determine the approximate time this infestation occurred. The infested trees are approximately 45 miles west from the nearest borer find in Winona County.

The inspection work with Minnesota Department of Agriculture and MnDOT experts was helpful to MnDOT Maintenance crews from Rochester and Stewartville, who were able to see firsthand the infestation and the telltale signs to look for when assessing an area.

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Because of this find, Olmsted County will join Hennepin, Houston, Ramsey and Winona counties in a state and federal quarantine. The quarantine is in place to help prevent the pest from spreading outside a known infested area into new areas. It is designed to limit the movement of any items that may be infested, including ash trees and ash tree limbs, as well as all hardwood firewood.

The borer is not very active at this time of year, so MnDOT will be organizing work crews to remove and properly dispose of the trees in October. At that time, crews will also do more work to determine the scope of the infestation. Dead trees were evident along the MnDOT right-of-way fence line.

Emerald ash borer larvae kill ash trees by tunneling into the wood and feeding on the tree’s nutrients. Since its accidental introduction into North America, the borer has killed tens of millions of ash trees in 24 states.

The metallic-green adult emerald ash borer beetles are a half-inch long, and are active from May to September. Infestation signs include one-eighth inch, D-shaped exit holes in ash tree bark and winding tunnels under the bark.

The Minnesota Department of Agriculture reports that Minnesota is highly susceptible to the destruction. The state has approximately 1 billion ash trees, the most of any state in the nation. The pest was first discovered in Minnesota in 2009. The last time a county was added to the quarantine was in 2011 when an infestation was discovered in Great River Bluffs State Park in Winona County.

The biggest risk of spreading the borer comes from people unknowingly moving firewood or other ash products harboring larvae. The Minnesota Department of Agriculture says there are three easy steps Minnesotans can take to keep it from spreading and offers good information for Minnesotans to understand the issue:

Don’t transport firewood. Buy firewood locally from approved vendors, and burn it where you buy it;

Be aware of the quarantine restrictions. If you live in a quarantined county, be aware of the restrictions on movement of products such as ash trees, wood chips, and firewood.  Details can be found online at

Watch your ash trees for infestation. If you think your ash tree is infested, go to and use the “Do I Have Emerald Ash Borer?” checklist or contact MDA’s Arrest the Pest Hotline by calling 888-545-6684 or emailing to report concerns.