Insects and Spiders - native

unknown on Aug 22, 2023

Originally reported as Emerald Ash Borer (Agrilus planipennis)

Submitter does not have a specimen

Description of specimen

I google lensed the insect and it identified. It was shiny emerald and fit the exact description of the emerald ash borer. This is very concerning since I know they are only known to infect ash trees!


Thank you for your report! There are a number of iridescent green look-alike beetles in Oregon that are not pests. I am attaching a link to the ODA EAB webpage with some photos of Oregon insects that could be mistaken for EAB

Tom Valente
Aug. 22, 2023, 1:43 a.m.

If the insect was found under the bark of pine tree, then it is definitely not EAB. EAB only attacks and breeds in a few species in the olive family, including ash. It does not feed on pine or other conifers.

Wyatt Williams
Aug. 22, 2023, 7:53 a.m.

The pine trees in your pictures appear to be dying from what looks like Mountain pine beetle. Recommend to cut and remove the dead trees, and thin (remove) some of the smaller, weaker, smaller pines in that row, or any damaged pines or pines with multiple tops. That will give the remaining pines more resources (water, light and nutrients) to fight off beetles. If possible, slow, deep watering of individual trees about once per month, June-August, will help give the remaining trees resources to fight off attacks.

Here is the ODF fact sheet on Mountain pine beetle:

Wyatt Williams
Aug. 23, 2023, 3:14 a.m.

For dying western red cedar (which was not visible in your photos so I am taking a guess here), we have been observing widespread mortality for the last 4-5 years. After large field study with cooperators, it has been determined that western red cedar mortality is primarily due to drought. So the recommendation above for watering pine trees would also apply to western red cedar.

Here is the ODF fact sheet on western red cedar mortality:

Wyatt Williams
Aug. 23, 2023, 3:18 a.m.

Given that you have western red cedar dying, I am going to take a guess and say that the green irridescent beetle that you observed is the western cedar borer, Trachykele blondeli. It is really common in dying western red cedar, but it is not a tree-killer. It comes in after the tree is already well on its way out (which is a slow death, 1-2 years).

Western cedar borer is #4 in the EAB lookalike guide that Tom posted above:

Wyatt Williams
Aug. 23, 2023, 3:23 a.m.