Help Stop the Beetle Killing Southern California’s Oak Trees

Claifornia residents can join a volunteer “blitz” this June to help detect and map infestations of an invasive beetle that is killing thousands of oak trees across Southern California.

1 minute read

May 27, 2025, 8:00 AM PDT

By Clement Lau


Close-up of black and yellow oak borer beetle.

Mike Lewis, CC BY 3.0, via Wikimedia Commons / Wikimedia Commons

The goldspotted oak borer (GSOB), a small but destructive beetle, is killing tens of thousands of oak trees across Southern California by burrowing under their bark and disrupting their ability to transport water and nutrients. This invasive pest poses a serious threat to native oak woodlands, which serve as crucial habitat for wildlife and are vital to the region’s ecological health.

To combat this growing threat, the University of California Cooperative Extension (UCCE) is launching a region-wide “GSOB Blitz” from June 1 to June 15. The initiative will mobilize volunteers across six counties — Los Angeles, Ventura, San Diego, Orange, Riverside, and San Bernardino — to detect and map GSOB infestations. UCCE is partnering with CALFIRE, the U.S. Forest Service, Irvine Ranch Conservancy, and other community organizations to train and lead volunteer groups.

No prior experience is needed to participate. Volunteers will receive training through an online course and a live webinar on May 27, along with field supplies and instructions on the day of their local blitz. By joining this community science effort, volunteers will play a critical role in protecting Southern California’s iconic oaks from further devastation. More information and registration details can be found at ucanr.edu/gsob-blitz.

Thursday, May 15, 2025 in University of California Agriculture and Natural Resources

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I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

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