ISSUE 13   August 13, 2009


There is much concern about the movements of emerald ash borer (EAB) as it gets closer to North Dakota, and citizens want to protect their ash trees from this devastating insect pest. As a result, NDSU Extension Service, North Dakota Department of Agriculture (NDDA), and North Dakota Forest Service (NDFS) have established the following position statement on the practice of insecticide treatments for control of EAB.

The nearest known infestation of EAB is St. Paul, MN. There are no known populations of EAB in North Dakota or any points west of St. Paul.

Once EAB is detected in North Dakota, ash trees within 15 miles of an infestation may be at risk and treatment of high value ash trees along streets or in yard settings may be warranted. Controlling insects that feed under the bark has always been difficult so homeowners must make sure to weigh the costs of annual treatment with the value of their ash tree. It is not practical to treat ash trees in woodlots, shelterbelts , or other large tree plantings.

Each year EAB is found in new locations, sometimes far from previously known infested areas, so it is important to be aware of the current known distribution. Current maps of known EAB populations can be found at:

Insecticides treatments for EAB continue to be a work in progress. Success rates have been variable in university tests conducted in EAB-infested states. Reference materials for EAB insecticide trials can be found at www.emerald In time, insecticides may prove to be more effective to protect individual high value ash trees. Research is needed to determine which products and which methods of application will work best for ash growing in the North Dakota environment once EAB arrives.

The NDDA, NDFS, and NDSU Extension Service emphasize the need to increase tree species diversity, removing unhealthy, low-value ash from the landscape, and taking actions to delay the introduction of EAB into North Dakota as long as possible.

The NDFS in conjunction with the NDDA continues to focus on outreach efforts regarding the dangers of firewood transport and surveying high risk sites for EAB. The public can play an important role by becoming familiar with the signs and symptoms of EAB and reporting suspicious situations.

Janet Knodel
Extension Entomologist

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