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Woodboring Pests

Benton County is home to a diverse range of ecosystems and important species that depend on them. A few notable examples of these ecosystems include oak woodlands and savannas, wet prairies, and riparian zones bordering the Willamette River and all of its tributaries. Two widely known keystone tree species you find in these habitats respectively are Oregon white oak (Quercus garryana) and Oregon ash (Fraxinus latifolia). 

A large tree with green leaves under a clear blue sky, next to a grassy field.
Oregon white oak tree. Photo by Cierra Dawson.
Green oak leaves on a branch with lichen, surrounded by grass.
Oregon white oak leaves. Photo by Cierra Dawson.
A dirt path through a grassy field, flanked by large green trees under a partly cloudy sky.
Oregon ash tree. Photo by user born1945 on Wikimedia Commons.
Green leafy plant with clusters of pale seed pods hanging from its branches.
Oregon ash tree leaves. Photo by user born1945 on Wikimedia Commons.
A large tree with green leaves under a clear blue sky, next to a grassy field.
Green oak leaves on a branch with lichen, surrounded by grass.
A dirt path through a grassy field, flanked by large green trees under a partly cloudy sky.
Green leafy plant with clusters of pale seed pods hanging from its branches.

Both of these critical tree species are under threat because of woodboring pests in the state of Oregon. In 2018, a single adult Mediterranean Oak Borer (Xyleborus monographus MOB) beetle was detected in Multnomah County and the population has since expanded from there. Then, in 2022, a destructive woodboring pest called Emerald Ash Borer (Agrilus planipennis EAB) was detected in Washington County for the first time—marking the first confirmed detection of this pest on the west coast of the United States.

A vibrant, metallic green and pink beetle on a leaf.
Emerald ash borer. Photo by Oregon Department of Forestry.
A metallic green beetle on a leaf.
Emerald ash borer. Photo by Oregon Department of Forestry.
Close-up of a small brown beetle on a wooden surface.
Mediterranean oak borer. Photo by Oregon Department of Forestry.
Close-up of a spiny brown beetle with fine hairs on its back.
Male Mediterranean oak borer with horn-like structure. Photo by Oregon Department of Forestry.
A vibrant, metallic green and pink beetle on a leaf.
A metallic green beetle on a leaf.
Close-up of a small brown beetle on a wooden surface.
Close-up of a spiny brown beetle with fine hairs on its back.

 Protecting our important Benton County trees starts with all of us. If you see something, say something. 

If you suspect that you have seen either of these destructive woodboring pests, report it now online to the Oregon Invasives Hotline or call 1-866-INVADER.

Learn more about Emerald Ash Borer 
Learn more about Mediterranean Oak Borer