The emerald ash borer, a highly destructive forest pest, has been confirmed in several new locations across northwest Oregon, including Beaverton, Salem, and the Rockcreek area. The Oregon Department of Forestry announced the findings after traps set earlier this spring were checked in July.

Impact on Local Trees

The emerald ash borer infests and kills ash, olive, and white fringetrees, and its larvae kill trees by feeding on living tissue located under the bark. All American and European ash species, including native Oregon ash, are susceptible to the beetle.

New detections were confirmed at Bethany Lake Park in the Rockcreek area and at the Oregon Garden in Silverton. The beetle was also found along the Banks-Vernonia State Trail, marking the first time the pest has appeared in an Oregon state park.

City Preparations

The City of Salem has spent several years preparing for the infestation by inventorying nearly 4,000 ash trees along streets and in natural areas. The city halted the planting of new ash trees and began pre-emptive removals of trees in poor health. In 2025, officials began injecting insecticide into 600 trees in the northern part of the city to protect them from the beetle.

Beaverton officials began mitigation efforts after receiving a one-year grant from the Tualatin Soil and Water Conservation District in October 2024. The city used the funds to treat 600 of its 2,000 inventoried ash street trees. Jered Lane, Beaverton city arborist and public works supervisor, said the city has also planted 60 new street trees with the help of volunteers.

Kat Bethea, an emerald ash borer specialist with the Oregon Department of Forestry, said the adult beetles are only active from June through September. Signs of an infested tree include thinning or yellowing leaves, bark splitting, D-shaped holes in the bark, and shoots growing from the trunk or branches.

Original reporting: KTVZ (Central Oregon) — read the source article.