Do not drop off diseased plant material or insects at South Coast Research and Extension Center. The Orange County Extension Office does not take samples for identification.
The Orange County Agricultural Commissioner can help with identifying plant diseases and plant pests. Their website has instructions for preparing a specimen.
Agricultural Commissioner's Office
The Agricultural Commissioner's office no longer has a resident entomologist. Pest samples submitted to this office are now being sent up to Sacramento for identification, so the response time may increase significantly. Once the disease or pest is identified, you will receive a letter in the U.S. mail from Sacramento. The local office is no longer able to answer phone questions about the status of a pest submittal.
Orange County Mosquito and Vector Control can identify insects samples (no live specimens).
Their website has instructions for insect identification.