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Emerald Ash Borer

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Emerald Ash Borer (EAB) is an invasive, destructive insect that kills ash trees – those in the genus Fraxinus – throughout North America. It was first discovered in the U.S. in 2002 near Detroit, Michigan, where it had been for 5-10 years before it was finally discovered.

A street with dead ash trees from Emerald ash borer damage
Trees killed by emerald ash borer
Sections

EAB was found in North Dakota in August 2024, at a rest stop in a rural area eight miles north of Edgeley (LaMoure County). It has been slowly spreading across nearby shelterbelts since the initial find. The insect was next found in Fargo in January 2026. While the initial infestation in Fargo was confined to a few blocks in downtown, it will likely spread quickly as insect populations slowly build. Both LaMoure and Cass Counties are currently under quarantine from the ND Department of Agriculture - see map. Moving firewood and other ash products from these counties is prohibited.Transporting infested firewood spreads the insect much farther than it would fly on its own, and is the number one way that new areas get infested. More information about EAB and the regulations regarding this pest are found on the ND Department of Agriculture’s EAB website.

Latest Maps showing EAB infestations

Identification

Identifying EAB-infested ash trees is difficult. The first step is determining if the suspect tree is actually an ash. See NDSU Extension's publication Ash Tree Identification or the video below.

It’s difficult to identify infested trees based only on external symptoms. The symptoms that EAB causes can be attributed to a number of other insects or diseases that affect ash trees in our area. More information about identifying EAB itself can be found in these NDSU Extension publications:

If you believe that you have a tree that is infested with EAB, contact the ND Department of Agriculture through their web form or email.

A tree trunk showing signs of damage from Emerald ash borer
Emerald ash borer galleries.

Options for dealing with a confirmed EAB infestation

Treatments

There are several insecticide treatments that are available for EAB. However, treatments are effective only for individual trees, not for entire forests. Additionally, treatments can be expensive and must be continued throughout the life of the tree, or as long as a local infestation persists – 10 to 20 years. Tree owners must balance the costs of treatments, the long-term benefits of those individual trees, with the costs of removal and replacement trees, and the benefits that the new trees will provide.

We don’t recommend treating trees unless EAB has been found within 15 miles of your location. On its own, EAB spreads about a half-mile per year, with a maximum of 10 miles. More information about insecticide treatments is available in the NDSU Extension publication Emerald Ash Borer: Biology and Integrated Pest Management in North Dakota.

Many effective products are available to homeowners, though the most effective products are those that injected into the stems of the trees, often with specialized equipment used by professionals. Costs are highly variable.

Insecticide injection system next to a tree
Tree injection system.

Tree Removals

If you decide to remove one tree, or many, we recommend that you check the credentials of prospective tree-care companies, ensuring that they have a North Dakota Contractor’s License and maintain appropriate insurance. The International Society of Arboriculture (ISA) maintains a list of individuals who have earned their Certified Arborist credential.

There is no single list of tree-care companies in North Dakota. In Minnesota, you can search the Tree Care Registry.

Replacements

Green ash (scientific name Fraxinus pennsylvanica) is the most common tree species in North Dakota. In some communities, green ash makes up more than half of the tree canopy. Diversification of the urban forest, as well as shelterbelts and other conservation plantings is critical.

See the ND Tree Selector to learn more about potential tree species that can be used to replace green ash. A specific focus on elm trees can be found in the NDSU publication Elms for North Dakota.

Landscape with a mix of different kinds of trees
Diverse tree planting.

Community-wide management

Management options at the community level are the same as those for individual trees. Communities will use some combination of insecticide treatments and tree removals/replacements. The main difference is simply coordinating management of the large number of publicly owned trees found in our urban areas. Additionally, determining which trees are public responsibility versus private property varies from one community to the next, and is sometimes unclear. For more information, see Emerald Ash Borer: What's the plan for your community?

Contacts

If you suspect that your ash tree might have EAB, please contact your local county Extension agent. You can also contact the ND Department of Agriculture through their web form or email.

Additional cooperators include: