Goldspotted Oak Borer (GSOB) is an invasive pest that is accounting for large numbers of oak tree mortalities throughout San Diego County. GSOB is now spreading to Orange and Riverside counties as well.

GSOB adults feed on oak foliage. Females lay eggs in cracks and crevices of the oak tree’s bark. Once eggs hatch, larvae burrow into the tree where they feed beneath the bark of the trees. Larvae feeding will kill sections of cambium, which eventually results in tree death.

It is highly recommended if you are in a “GSOB Zone of Infestation (ZOI)” to have a management plan in place for GSOB control.

Any Oaks showing decline/ discoloration or symptoms of GSOB prior to treatment may not fully recover.

Any Oaks showing advanced stages of decline (40% +), and rapidly discoloring foliage should be evaluated for removal immediately, in effort to reduce possible spread to nearby oaks.

Along with suggested treatments, reducing plant stress by properly irrigating along the mid to outer drip line with deep and infrequent irrigation Fall – Spring. Also reducing large cuts or pruning during Spring-Fall when pests are most active.

It’s important to note that if your oaks are candidates for insecticide treatment, that a trained, qualified and licensed pest control applicator makes the application. Certain insecticides are restricted and improper applications can have significant negative impacts on natural enemies, bees, wildlife, and water quality.

APC is a GSOB treatment specialist and has all the required licensing, experience and knowledge to help treat your oaks for GSOB control.