Volunteers needed for “blitz” to stop oak-killing beetle

Submitted by pkanrice on May 14th, 2025

Pamela S Kan-Rice

San Diego

Ventura

Los Angeles

Orange

Riverside

San Bernardino

Natural Areas and Natural Environment

Pest Management & Plant Health

A dead oak tree among healthier oaks — Goldspotted oak borer, or GSOB, has killed tens of thousands of mature oaks across Southern California.

SoCal community invited to help map goldspotted oak borer infestations in June

A tiny beetle is causing big problems for Southern California’s oak trees. Goldspotted oak borer larvae tunnel beneath the bark and feed on the tissues that transport the tree’s water and nutrients, slowly starving the tree from the inside out. After several years of repeated infestations, the tree dies.

Goldspotted oak borer, or GSOB, has already killed tens of thousands of mature oaks across the region – threatening oak woodlands that provide vital habitat for wildlife.

Two beetles side by side fill about 1/3 of a copper penny — Adult GSOB are tiny, a fraction of a penny, but can kill large trees.

To save oak trees, University of California Cooperative Extension is organizing a GSOB Blitz, a community-powered effort to detect and map goldspotted oak borer infestations. Between June 1 and June 15, local survey events will take place across San Diego, Orange, Riverside, San Bernardino, Los Angeles and Ventura counties.

UCCE is collaborating with well-established agency and community partners to help lead volunteer groups in each of the six counties.

“Since 2009, the GSOB education and outreach program has been developed as a collaborating, coordinating workgroup effort,” said Jan Gonzales, UCCE community education supervisor and project coordinator in San Diego County. “We are pleased that this GSOB Blitz includes many of our community partners such as CALFIRE, U.S. Forest Service, Irvine Ranch Conservancy, a couple of Natural Resource Conservation Districts, Fire Safe Councils and representatives with various county departments.”

Volunteers don’t need experience, UCCE and collaborators will provide training in how to spot signs of GSOB.

Beetle on a green leaf — Volunteers will receive training to spot GSOB and signs it leaves on trees.

How to Participate

Complete the self-paced, online GSOB course. A link to the course will be sent to people who register.
Attend the GSOB Blitz Training Webinar on May 27, at 1-3 p.m. It will be recorded and posted for people who miss the live webinar.
On the day of your local blitz, meet your group at the designated time and place.
Receive your GSOB Blitz Bag with supplies and instructions.
Head out with your team to survey oak trees and collect data.

To volunteer or for more information, please visit https://ucanr.edu/site/goldspotted-oak-borer/gsob-blitz.