California Prionus Beetle (Prionus californicus) on Jul 29, 2025
Originally reported as Ponderous Borer (Trichocnemis spiculatus)
Submitter has sample
Description of specimen
Large brown beetle
Commentary
Thank you for your report! This is actually California prionus rather than Ponderous borer, but they are closely related and have similar lifestyles: they are not pests and you can let it go. These beetles are natives that breed in decaying conifer stumps and logs. They rarely attack the roots of living trees.
Tom Valente
July 30, 2025, 4:54 a.m.
Location
We have a horse boarding facility in West Linn. I found this beetle stuck in a plastic container outside. Should I just let her go, or would someone want her?
Tom Valente
July 30, 2025, 4:54 a.m.