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

Weeds & Pests

Polyphagous Shot Hole Borer

Polyphagous shot hole borer
The Polyphagous Shot Hole Borer (PSHB) is a new pest in Southern California. This boring beetle, from the group of beetles known as ambrosia beetles, drills into trees and brings with it a fungus (Fusarium sp.). It is tiny, about 0.1 inch in length.

The beetle attacks a wide range of native, ornamental, and horticultural trees. The fungus destroys the food and water conducting systems of the tree, eventually causing stress and dieback.


Both the fungus and the beetle were found on several backyard avocado (cv. Hass, Bacon, Fuerte, Nabal) trees in residential neighborhoods and commercial avocado groves in South Gate, Downey and Hacienda Heights, and several public arboretums in Los Angeles and Orange Counties.

Read more about this new pest at the following sites:

Pests and Diseases of Southern California Oaks

Center for Invasive Species Research (good photographs of the pest and tree damage)


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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