UCCE Orange County Master Gardeners
University of California
UCCE Orange County Master Gardeners

Weeds & Pests


How to have a pest or plant disease identified

There are two organizations in Orange County to which you can submit specimens for identification: Orange County Vector Control and Orange County Agricultural Commissioner. These services are free of charge.

OC Vector Control District is located at:
13001 Garden Grove Blvd
Garden Grove, CA 92843
Main line: (714) 971-2421 or (949) 654-2421
Fax (714) 971-3940
Click here for information about services offered by OCVCD

Insect specimens may be delivered in person to the above office with a filled-out form which can be printed from the website.

OC Agricultural Commissioner is located at:
Agricultural Commissioner's Office
Orange County
222 E. Bristol Lane
Orange, CA 92865-2714
Telephone (714) 955-0100
Fax (714) 921-2713

Specimens of insects, mites, snails, and slugs can be submitted for identification. Click here for an explanation of identification services.  You can download the necessary form to fill out and then submit the sample and the form in person or by mail to the above address.

If you capture any suspect insects, place them into a zip-lock baggie and place into the freezer.  Once frozen, send it to the OC Agricultural Commissioner's office for positive identification. You can also deliver live insects (properly packaged) in person. Below is the information on how to package and send a specimen.

Procedure for submitting insect, mite and mollusk specimens:
Specimens of insects, mites, snails and slugs will be identified if specimens are isolated in clean, clearly marked containers or adhering to fresh plant material. Specimens received in rotted condition or specimens requiring extensive processing to find suspected organisms will not be processed.
Dead, dry insects should be protected from mail handling by placing them in small boxes or dry vials (empty film canisters or pill bottles work well for this purpose).

Insects or mites attached or restricted to plant material are best submitted on a small portion of the affected plant placed in newspaper and placed in an open ended plastic bag before packaging for mailing.

Plant-associated mites should be placed in a vial in a small amount of isopropyl alcohol (rubbing alcohol) and submitted in person to the Agricultural Commissioner Office.  Live mollusks are best submitted in person to the Agricultural Commissioner’s Office in small boxes or ventilated glass jars.

Procedure for submitting plant disease or plant specimens for identification:
The sample should be as fresh and complete as possible with examples of roots, stems, flowers, fruits, and/or leaves depending on the perceived symptoms. These should not be placed in plastic since this runs the risk of becoming cooked or decomposed beyond recognition. If specimens are not possible, as with trees or a lawn, a picture can be helpful. 

The sample should be representative of the symptoms, in the diseased or dying stage but not completely dead. Once a plant is dead, microorganisms that decay organic matter start to grow, making it difficult to diagnose what originally caused the plant to die.  When a sample consists of only a few leaves, grass clippings, or pieces of bark, it is difficult to make a proper diagnosis.

If you can’t find the answer on the site, don’t despair! We also have the capacity to personally assist you through our hotline.  Just contact us by email or by phone (voicemail) at 949 809-9760 and we will respond to your inquiry.
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