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Goldspotted Oak Borer

The goldspotted oak borer (GSOB) Agrilus auroguttatus (Coleoptera: Buprestidae), is a wood borer native to southeastern Arizona, southern Mexico, and northern Guatemala.  It is believed to be introduced into California and was first collected in San Diego Co. in 2004.  In 2008, GSOB was linked to continuing oak mortality occurring since 2002 across all land ownerships.  Tree mortality associated with GSOB was estimated at >20,000 covering an area of 4903 km2 (2009).  Extensive larval feeding at the interface of the phloem and xylem leads to tree mortality after several years of injury.  The goldspotted oak borer is currently the most significant insect threat to oaks in California and its known hosts range from southern California up to Oregon.  Oak mortality is impacting aesthetics, property values, increasing health hazards in high-use areas, diminishing wildlife habitat, and changing the fuel structure in areas prone to wildfire. This borer is also attacking and killing oaks in Riverside County in Idyllwild. Multiple infested trees have been detected.

GSOB Information

Current GSOB Activities: Entomology and Pathology

  • Surveying and monitoring for the presence of GSOB in California
  • Developing integrated pest management strategies
  • Enhancing survey and trapping methods
  • Determining the life cycle of GSOB
  • Survey the native regions of GSOB (Arizona and Mexico) for life history information
  • Assessing the impact of GSOB in forest stands
  • Assessing management options for infested wood material
  • Conducting insecticide trials
  • Developing biological control options
  • Assessing pathogens associated with GSOB injury
  • Developing education and outreach materials

Collaborators with FHP on GSOB Studies

  • USDA Forest Service, Pacific Southwest Research Station
  • USDA Forest Service, Southern Research Station
  • USDA Forest Service, Northern Research Station
  • University of Massachusetts, Amherst
  • Animal Plant and Health Inspection Service
  • University of California, Riverside
  • University of California, Davis
  • Forest Health Protection, Region 3
  • Cleveland National Forest
  • Coronado National Forest
  • California Department of Forestry and Fire Protection

FHP GSOB Evaluations







GSOB Publications

Outreach Publications

Contact Information:

Tom Coleman

Forest Entomologist
(909) 382-2871
Southern California Shared Service Area
San Bernardino National Forest
602 S. Tippecanoe Ave.
San Bernardino, CA 92408-3430