2013 Highlights: UC IPM Annual Report

Guidance for handling a new oak pest

Adult goldspotted oak borers. Larval to adult stages of the goldspotted oak borer.

Top, adult goldspotted oak borers; bottom, larva to adult stages. (Photos by M. I. Jones.)

Since its arrival in California in the late 1990s, the goldspotted oak borer (GSOB) has killed over 22,000 native California oak trees in San Diego County. The pest also recently invaded oak forests in areas of Riverside County. GSOB prefers the largest, most mature trees and threatens oaks in both forested wildlands and landscapes. Researchers believe it has the ability to spread throughout California wherever oaks are grown.

The new Pest Note Goldspotted Oak Borer from UC IPM provides land managers, landscape professionals, and homeowners with information for managing this devastating pest and distinguishing it from other common oak borers.

Unfortunately, there are currently no effective methods for controlling the pest in moderately to severely infested trees, so the focus of a management program must be protection of healthy trees. Authors Mary Louise Flint, Mike Jones, Tom Coleman, and Steve Seybold detail options for planting nonsusceptible tree species, treatment of wood from infested trees, and biological and chemical control. The most important way to keep the pest from spreading to new areas is to prevent movement in firewood or other infested wood products.


Statewide IPM Program, Agriculture and Natural Resources, University of California
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