08/25/2026
Emerald Ash Borer Has Arrived in Washington
A major new threat to Washington’s ash trees has been confirmed.
The Emerald Ash Borer (EAB) has been found near Vancouver, Washington, marking the first confirmed detection of this destructive invasive insect in our state. State officials confirmed the finding on August 19, 2026.
EAB is a small, metallic-green beetle that attacks ash trees (Fraxinus). Its larvae feed beneath the bark, disrupting the tree’s ability to transport water and nutrients. Once established, EAB can kill even healthy ash trees.
What does this mean for us here in the Tri-Cities?
The beetle has been moving westward for several years. It was detected in Oregon in 2022 and in Vancouver, British Columbia in 2023/2024. Now that it has reached Washington, ash tree owners throughout the state need to become familiar with the threat.
Watch your ash trees for:
• Thinning or dying branches, especially in the upper canopy
• New shoots growing from the trunk or base
• Vertical cracks in the bark
• Woodpecker activity
• S-shaped galleries beneath the bark
• Small, D-shaped exit holes made by adult beetles
One of the challenges with EAB is that an infestation can be present for several years before obvious symptoms appear. By the time a tree is showing significant decline, the infestation may already be well established.
What should ash tree owners do?
Don't panic — but don't ignore it.
If you have a valuable or mature ash tree on your property, now is a good time to have it evaluated. Depending on the tree's condition and circumstances, options may include monitoring, preventive treatment, or eventual removal and replacement.
And please remember: don't move firewood or ash wood unnecessarily. Moving infested wood is one of the ways this insect can spread to new areas.
At Artistic Treeworks, our work is evaluated and directed by ISA Certified Arborist Howard Madsen, who has more than 40 years of experience in arboriculture. If you have an ash tree and aren't sure what you should do, we're happy to help you understand your options.
Call Artistic Treeworks at (509) 943-4604 for an evaluation.
We'll be watching this developing situation closely and we will share additional information as it becomes available.
Know your ash trees. Know the signs. Don't wait until the tree is in decline.
📢 : Emerald ash borer has been detected in Washington State near Vancouver. This highly invasive and destructive pest kills up to 99% of ash trees. So far, this pest has not been eradicated in any area where it has been discovered.
Washington has prepared for the arrival of this pest by creating resources for government organizations and individuals. Check out our press release to learn more about this pest and get resources on what you can do now to prepare. https://agr.wa.gov/about-wsda/news-and-media-relations/news-releases?article=47256