The emerald ash borer is an invasive beetle that kills North American ash trees, including Oregon ash. According to Metro, the first was found in Oregon in Forest Grove in 2022. It has now been confirmed in five Oregon counties—Clackamas, Marion, Multnomah, Washington and Yamhill. There has even been a sighting at Metro’s own Killin Wetlands Nature Park.
While there is currently no way to stop the spread of the emerald ash borer, Metro offers suggestions on things that can be done to slow its spread. First, burn firewood where you buy it. One of the most common ways for the beetle to travel to new areas is by hitching a ride inside firewood that humans move. In general, burn firewood no more than 10 miles from where it was gathered.
Second, learn to identify ash trees and the signs and symptoms of infestation. More information on identification can be found at bit.ly/4mUpMF6.
When planting new trees, don’t plant ash trees. Until an effective treatment or strategy is available to combat the emerald ash borer, planting Oregon ash is likely to just give the invasive pest more food and more ways to spread. Instead, plant a diversity of trees and plants that are appropriate for the conditions of the site.
Finally, report sightings of the emerald ash borer. The adult beetles can be tough to find, as they spend much of their life cycle in the treetops. Still, look for them to emerge and begin flying in late May or early June. Reports can be made to the Oregon Invasive Species Online Hotline at oregoninvasiveshotline.org/reports/create.
Photo by David Cappaert Michigan State University, Bugwood.org; CC BY-NC 3.0.
