Hansen Agricultural Research and Extension Center
University of California
Hansen Agricultural Research and Extension Center

Essential Read:

Invasive shot hole borers (ISHB) are tiny beetles that are posing a significant threat in Ventura County and beyond. 

There's new information provided in this blog post by Wayne Farnsworth of BrightView Tree Care Services and Randall Oliver, UC ANR Integrated Pest Management Program. It appeared on the Channel Islands Chapter of the Community Association Institute website.

These pests are becoming established in parts of Ventura County. Farnsworth and Oliver note that "Unlike many insect pests, invasive shot hole borers infest a wide variety of tree species, including many common ornamentals, avocados and California natives. Sycamores and box elders are among their favorites, and they also attack live oaks, valley oaks and alders, all of which are abundant in our area."

Per UC ANR, invasive shot hole borers are

"two closely related species of small, non-native, beetles that bore into trees. ISHB introduce fungi that cause a tree 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." 


You can learn more about ISHB at the UC ANR Integrated Pest Management website.

As Julie Di Blasio reported last year, "...invasive shot hole borer (ISHB) infestations have been identified in Ventura County since 2015 but have not significantly spread. Discovery of the pest/disease complex was found in late 2018 in the urban forest of Meiners Oaks. Citizens Journal recently published an article about the removal of a tree that was at risk for amplifying the local infestation and causing potential other community harm."

UCCE Ventura has been collaborating to address ISHB with UC insect, disease, education specialists, Ventura County Agricultural Commissioner, CAL FIRE, US Forest Service, several other agencies and non-government organizations. We are locally active in monitoring and outreach. Ventura County Master Gardeners Invasive Pests Outreach Group augments our work through their efforts to educate the public, firewood users and vendors."


Image credit: Akif Eskalen, UC Davis/UC ANR



Invasive shot hole borer on coin - Akif Eskalen
Invasive shot hole borer on coin - Akif Eskalen

Photo of tiny beetle on a quarter coin to show relative size.

Posted on Saturday, January 30, 2021 at 3:03 PM
Focus Area Tags: Agriculture, Environment

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