Impact and management of the goldspotted oak borer, Agrilus coxalis, an invasive beetle in southern California oak woodlands

The goldspotted oak borer (GSOB), Agrilus coxalis, (Coleoptera: Buprestidae) is a new threat to oaks in southern California. The phloem borer was first collected in San Diego Co., California in 2004, but has been killing three species of oaks since 2002. We hypothesize that GSOB was most likely introduced on firewood from its native distribution in Arizona or Mexico. Over the past seven years, aerial surveys have detected an estimated 17,000 dead oaks across a 1200 km2 area. Long-term survey plots have been established in and around the zone of infestation to assess forest stand conditions, GSOB-caused mortality, and current infestation rates. As a primary management tool to slow the spread of GSOB in California, we are evaluating solarization treatments of GSOB-infested firewood such as 1) Direct sun exposure; 2) Tarping with clear plastic; 3) Caging of firewood to monitor normal woodborer emergence (control treatment).