Emerald Ash Borer Appears To Be Spreading In Washington

A destructive invasive insect appears to be spreading across Washington. The state Department of Ag has confirmed emerald ash borer in Walla Walla County. The pest was only recently discovered in Washington, found in the SW corner of the state in August.

Investigators say a College Place area arborist noticed and reported potential EAB damage. Upon receiving the report, WSDA responded to the location and discovered multiple larvae as well as D-shaped holes — typical of emerald ash borer infestations — in multiple ash trees. WSDA collected specimens and sent them to USDA, which confirmed the specimens as emerald ash borer on October 14th.

Photo: Deborah Miller, USDA Forest Service

Lethal For Ash

Emerald ash borer is an invasive insect that has proven to be one of the most destructive forest pests in North America. Since its initial detection in the United States two decades ago in Michigan, emerald ash borer has wiped out more than 100 million ash trees throughout the country.

All true ash species, including Oregon ash, the Pacific Northwest’s only native ash, have proven vulnerable to EAB. A Washington State Department of Natural Resources (DNR) analysis found that without taking action to manage an outbreak, a municipality should expect to lose 90 – 100% of its ash tree inventory within 10 – 12 years of an initial EAB infestation.

See Something, Say Something

Washington residents are urged to be vigilant and report suspected sightings to WISC by using one of the following options:

Online at invasivespeciaswa.gov
The Washington Invasives app available for free on Google Play and the Apple App Store.
Email screenshots, links and as much additional information as possible about reports made on social media or other platforms such as iNaturalist or Nextdoor to invasivespeciesinfo@rco.wa.gov.
Preserve physical specimens as you are able by placing the insect in a plastic bag and freezing it. You may also place it in a vial with ethanol or isopropyl alcohol. Please write your name, the date and where the insect was sighted (GPS coordinates preferred) on the container.