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Invasive Shot Hole Borer

What Is ISHB? ¿Qué es ISHB?

  • Invasive shot hole borers (ISHB) (Euwallacea spp.) are two species of genetically distinct, but physically identical, non-native beetles: Polyphagous shothole borer (PSHB) and Kuroshio shothole borer (KSHB).
  • These small beetles bore into trees and spread a disease called Fusarium dieback (FD). 
  • The ISHB-FD pest-disease complex is responsible for the death of thousands of trees in Southern California and poses an imminent threat to the integrity of our urban and natural forests.
  • Invasive shot hole borers attack a wide variety of tree species including avocados,  common landscape selections, and California native species in urban and wildland environments.

Stop the Spread of ISHB-FD

    1. Don't move firewood!
      Many wood-boring pests, including ISHB, are spread by the transport of infested wood. Buy firewood where you intend to burn it. Visit dontmovefirewood.org and www.firewood.ca.gov for additional resources and information that you can share with others.

                dontmovefirewood   buyitwhereyouburnit

    2. Properly dispose of infested material
      Do not use untreated ISHB-infested logs or chips for firewood or mulch. Options for treating infested material include solarization, composting, kiln-drying, and biogeneration. Learn more about these options here.

    3. Disinfect pruning tools
      Poor pruning practices can facilitate the spread of plant disease. Any pruning, sampling, or other tools that come into contact with infected wood should be sanitized before being used on uninfected trees. This includes chainsaws and wood chipping equipment. If several infested and uninfested trees need to be maintained on a property, we recommend managing the trees in batches. First take care of all of the uninfested trees, then move to the infested trees so that your tools won't need to be cleaned until the end of the day. 

For pruning and tool sterilization tips, see UC Riverside's "Best Management Practices for Disease in Oak Woodlands" .

Video Resources

Learn more by watching videos:

ISHB Look-Alikes

Other pests cause similar symptoms in these trees:

For more information, see UCANR publication 240640 (on Invasive Shot Hole Borer)

ISHB - What to Look For_source-ANR pub 240640
ISHB - What to Look For_source-ANR pub 240640