OLYMPIA – The Washington State Department of Agriculture (WSDA) and the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) confirmed a report of emerald ash borer in Vancouver.

Emerald ash borer (Agrilus planipennis) 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 (EAB) has wiped out more than 100 million ash trees throughout the country.

All true ash species (Fraxinus), 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.

There are no reliable methods to stop the spread or contain an outbreak of EAB other than limiting the transportation of firewood, removing affected ash trees, and replacing them with non-ash species that are not susceptible to EAB or other common pests. A firewood quarantine adopted by WSDA to prevent the introduction and spread of invasive insects and diseases took effect on August 18.

There has never been a successful effort to eradicate EAB. Land managers and homeowners should immediately cease planting new ash trees.

“We anticipated it would only be a matter of time before emerald ash borer arrived in our state,” WSDA Pest Program Manager Sven Spichiger said. “This is yet another example of how alert, observant members of the public help us detect new, invasive pests.”

Two vigilant citizens spotted the insect on their windshield on Monday, August 3. After learning it was invasive and should be reported, they collected the specimen and submitted a report to the Washington State Invasive Species Council (WISC), which alerted WSDA. The pair later turned the specimen over to a Washington State Parks employee, who gave the specimen to WSDA on August 5. WSDA submitted the specimen to USDA on August 6 and USDA confirmed the specimen as EAB on August 19. 

Their report contained not only several high-quality images, which aided identification, but they captured and submitted the beetle, which saved responding agencies from needing to expend resources surveying for an official specimen. 

The discovery follows the insect’s continued westward spread. EAB has been active on the West Coast since its detection in Forest Grove, Oregon in June 2022. Scientists discovered EAB activity a year later in Vancouver, British Columbia. Native to eastern Asia, the metallic green insect measures about one-half inch in length and is often identified by the D-shaped exit holes it leaves in affected trees.

“This is deeply unfortunate, but we knew the emerald ash borer would arrive here, and we’ve been preparing for it,” Commissioner of Public Lands Dave Upthegrove said. “Please use our shared resources to educate yourselves and heed the recommendations to slow the spread of this destructive pest.”

Collaborative planning efforts, monitoring for continued spread, and community preparedness initiatives will be essential for mitigating and managing the spread of emerald ash borer in Washington state.

The DNR Urban and Community Forestry Program, WSDA, WISC, and Washington State University Extension (WSU) have led a collaborative effort in recent years to publish the State of Washington Urban Forest Pest Readiness Playbook and the Washington State Emerald Ash Borer Resource and Management Guide.

Both documents include detailed recommended actions for local governments to draw from as they plan their own EAB responses. These and related resources may be found at treehealth.wsu.edu/eab.

Financial and technical assistance for municipal urban forestry activities will continue to be provided by the DNR Community Forestry Assistance Grant Program as long as funding remains available. Technical assistance from DNR is available to local governments, special use districts, tribes, schools, and 501c3 non-profit organizations, and may be requested using a new online portal.

“With emerald ash borer now a confirmed presence in Washington, these programs, guides, and resources have never been more relevant than they are now,” said WISC Executive Coordinator Jan Fore. “Landowners, educators, resource managers and the public can use these tools to limit the spread and impact of the emerald ash borer around the state.”

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.

State agencies will continue working closely with partner organizations to provide updates about EAB spread as they are warranted.