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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 ash trees showing signs of Emerald ash borer damage
Trees infested with emerald ash borer
Sections

As of March 2, 2023 EAB has not been found in North Dakota, though it was found in Moorhead, Minnesota, in February 2023. The Minnesota Department of Agriculture has established a quarantine around the western half of Clay County, MN, and will complete a delimiting survey in April 2023 to determine the extent of the infestation.

News Release from the ND Dept. of Agriculture - March 2, 2023

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.

Remote video URL

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.

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: