March 31, 2021

The Minnesota Department of Agriculture (MDA) has confirmed emerald ash borer (EAB) in Blue Earth County. There are now 27 counties in the state with EAB.

A resident in the city of St. Clair was cutting down an ash tree and noticed insect galleries in the wood. The homeowner contacted a local Department of Natural Resources forester who notified the MDA. MDA staff were able to find live EAB larvae and collect samples for federal identification.

Emerald ash borer larvae kill ash trees by tunneling under the bark and feeding on the part of the tree that moves nutrients up and down the trunk. Often, the trees show several signs of infestation because of this. Woodpeckers like to feed on EAB larvae and woodpecker holes may indicate the presence of emerald ash borer. Also, the EAB tunneling can cause the bark to split open, revealing characteristic S-shaped galleries underneath.

Because this is the first time EAB has been identified in Blue Earth County, the Minnesota Department of Agriculture is enacting an emergency quarantine to limit the movement of firewood and ash material out of the county. The MDA issues quarantines for all counties known to have EAB to reduce the risk of further spreading the tree-killing insect.

Two virtual open houses for residents and tree care professionals in the county will be held on Wednesday, April 21. Experts from the MDA will give a brief presentation followed by a question-and-answer session.

Emerald Ash Borer Virtual Informational Meetings
Wednesday, April 21
10-11 a.m. or 6:30-7:30 p.m.
Register at

The public will also have an opportunity to provide input on the proposal to add Blue Earth County to the state formal quarantine. The MDA is taking comments on the proposed formal quarantine now through May 17 and recommends adopting the quarantine on May 21. The quarantine limits the movement of ash trees and limbs and hardwood firewood out of the county. The proposed quarantine language can be found at

Comments can be made during the virtual meeting or by contacting:

Kimberly Thielen Cremers
Minnesota Department of Agriculture
625 Robert Street North
St. Paul, MN 55155
Fax: 651-201-6108

EAB was first discovered in Minnesota in 2009.

There is more EAB information on the MDA website at


Media Contact
Allen Sommerfeld, MDA Communications