What is Emerald Ash Borer?

Emerald Ash Borer (EAB) is an invasive insect that kills ash trees by tunneling under the bark and feeding on the tree. It has killed millions of trees throughout the United States. EAB kills both weak and healthy ash trees. The state of Minnesota is home to nearly a billion ash trees, making the impacts of Emerald Ash Borer significant. Emerald Ash Borer was detected in St. Michael by the Minnesota Department of Agriculture in early February 2023.  

How do I know if I have ash trees or if they are infected? 

Click here to find out or watch the video below:








What can I do if I have ash trees in my yard?

Ash trees can be treated with an insecticide to prevent emerald borer infestation but must be repeated every two to three years for the life of the tree. If you do not wish to treat your trees, consider having them removed now. If your ash trees become heavily infested or dead, it will be more expensive to cut down and remove later because the trees become dangerous to cut down.


Although residents can contact any tree company, the City has secured an agreement with Rainbow Treecare at a negotiated price for residents that wish to treat their ash trees. The negotiated rate is $7.25/per diameter breast heigh inch. Treatment cost depends on the tree size but is typically between $75-$200 per tree. For more information and to contact Rainbow Treecare, visit www.rainbowtreecare.com/st-michael.

Need help deciding what you should do? This guide is helpful to decide what the right choice is for you on managing your ash trees. 


EAB larva in gallery. Photo by Minnesota Dept. of AgricultureEAB gallery and exit hole. Photo by Minnesota Dept. of AgricultureEAB exit holes. Photo by Minnesota Dept. of Agriculture.EAB emerging through its D-shaped exit hole.Bark of ash tree with woodpecker flecking. Photo by Minnesota Dept. of AgricultureAsh tree showing classic woodpecker flecking. Photo by Minnesota Dept. of Agriculture

How can I help the spread?

Emerald ash borer moves quickly when people move infested ash firewood. A quarantine has been placed in a growing number of counties to help prevent its spread. Firewood and other ash products are regulated by the Minnesota Department of Agriculture.