Southern Californians Survey Trees for Destructive Oak Pest

The Goldspotted Oak Borer (GSOB), an invasive beetle responsible for widespread oak tree mortality in Southern California, was the focus of the region's first-ever “GSOB Blitz.” Organized by UC Agriculture and Natural Resources with support from CALFIRE and other partners, the event mobilized about 200 volunteers across five counties to search for signs of infestation, such as D-shaped exit holes in tree bark. Participants included representatives from various public agencies, students, arborists, retirees, and amateur entomologists who gathered valuable field data using a specialized app, contributing to updated beetle range maps and guiding future management efforts.

Training and hands-on fieldwork were key elements of the blitz. Volunteers were taught how to recognize signs of infestation and practiced data collection techniques in natural areas such as San Dimas Canyon Park. While some groups confirmed infestations—providing crucial data and awareness—others, like the Los Angeles County team, found no verified GSOB evidence. Nonetheless, all participants left empowered to monitor oaks in their own neighborhoods and advocate against firewood transport, a major vector for beetle spread.

The blitz sparked enthusiasm among both organizers and community members, demonstrating strong public interest in protecting native oak woodlands. Organizers plan to hold future blitzes due to high demand and encouraging results. Volunteers like Ismael Cervantes and Nathaniel Carbajal expressed deep personal motivation—ranging from love of bugs to aspirations in urban forestry—highlighting how accessible community science can foster environmental stewardship and fill critical monitoring gaps that professionals alone cannot meet.