Insects and Spiders - native

Ponderous Borer (Trichocnemis spiculatus) on Aug 2, 2026

Originally reported as Prionus species

Description of specimen

Submitter does not have a specimen

I found this huge 3" beetle on my front porch this morning 9am. I googled it and thought it might be a: Prionus californicus longhorn beetle. My house is within the city of Estacada, OR.

Commentary

Avatar of commenter Thank you for your report! No, this isn't a pest. This is the "Ponderous borer", Oregon's largest beetle. They are not tree killers. Their grubs live in dead conifer stumps and logs.

Tom Valente
Aug. 5, 2026, 8:18 a.m.

Location

My front porch 421 SE Cedar Creek Ln Estacada OR 97023

Expert Reviewer

Avatar of Reviewer

Tom Valente
Oregon Department of Agriculture

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