Emerald ash borer was found Sept. 4 in North Dakota for the first time. EAB is an invasive, destructive insect that eats the phloem layer of the tree, just under the bark.

Native to Asia, the pest was first discovered in the United States in 2002 in southeast Michigan. It can now be found in the Dakotas, Nebraska and Colorado. The U.S. Forest Service considers it one of the most invasive destructive species in North America.

All North American ash species can become hosts of the EAB, according to North Dakota State University. This includes green, black, Manchurian and white ash.

Control methods

Using an Integrated Pest Management system is the best approach to stave off this pest through monitoring and multiple control strategies.

Stopping the movement of firewood is one of the top cultural control strategies to employ to prevent the spread of EAB. Burn any logs where you purchase them, as larvae can hide under the bark. NDSU states that the spread of EAB in Michigan was due largely to firewood.

Removing infected or diseased trees to prevent larvae from spreading is another cultural control. Parasitoids are an option to treat pests, as the EAB has no natural predators aside from woodpeckers. Research is being conducted to discover any naturally occurring predators. A native wasp has been found in Michigan, and its habits are being researched.

Insecticide treatment of trees is available, but only individual trees can be treated rather than a forest. However, these treatments can be expensive and must be continued throughout the tree’s life, so owners must consider if treatment or removal is best.

The most effective product for homeowners is one that is injected into the trunk of the tree. This is often done by professionals, and the cost can vary widely.

Before treating any ash trees, homeowners should consider if their trees are in danger of being infected. NDSU does not recommend treating trees unless EAB has been found within 15 miles, as the pest only spreads about a half-mile annually on its own.

External signs of EAB can often look like other ash diseases, so official confirmation of their presence should be confirmed with officials. The North Dakota Forest Service, North Dakota Department of Agriculture or NDSU Extension should be contacted if you suspect EAB has moved into your land.

Find more information on EAB from NDSU Extension.