Emerald ash borer (EAB)

EAB Risk Status

Emerald ash borer (EAB) is a nonnative invasive insect that destroys ash trees. Quarantines have been placed in 14 counties to help slow the spread of EAB to other areas. It's against the law to move the following items out of EAB-quarantined counties:

  • Firewood from hardwood trees
  • Entire ash trees
  • Ash limbs and branches
  • Ash logs or untreated ash lumber with bark attached
  • Uncomposted ash chips and uncomposted ash bark chips greater than 1 inch in two dimensions.

Map of MN EAB Activities: Quarantines and Positive Finds external link

Click image to enlarge

View of woodpecher activity on ash tree.

View of woodpecher activity on ash tree.

Late winter is a good time to discover EAB infested ash by looking for woodpecker activity. Here is what to look for:

  • Light-colored patches on the trunk and large branches where woodpeckers have flaked off bark.
  • Holes within the light colored patches where woodpeckers have dug out larvae.

photo: Signs and symptoms of EAB

What you need to know

EAB kills ash trees, and it does so in great numbers. Already it has killed millions of ash trees in North America. EAB will have a huge effect on Minnesota's landscape and the 998 million ash trees that grow in our cities and forests.

  • Recognize the signs of an EAB-infested tree: heavy woodpecker activity on tree, dying branches in the top canopy, sprouts around the tree base, vertical cracks in the bark, S-shaped tunnels under the bark, and 1/8-inch D-shaped exit holes in the bark.
  • If you think your tree is infested refer to the Signs and Symptoms of EAB in Ash Trees slide show for more examples. Also review the reference for recognizing insect galleries external linkin ash trees in Minnesota.
  • If your ash tree is showing other signs, visit the What's wrong with my ash tree? external linkonline diagnostic tool to help identify problems caused by insects, diseases, and nonliving factors.
  • To report a possible EAB infestation, contact the Arrest the Pest Hotline at arrest.the.pest@state.mn.us external linkor 888-545-6684.
  • Consider insecticide treatments only when your property is within 15 miles of an EAB infestation. More information external link
  • Do not transport firewood, even within Minnesota.

Locations of EAB

graphic:EAB icons