What are the Polyphagous and Kuroshio Shot Hole Borers?

Infested tree, infested trunk, adult beetles in galleries

The Polyphagous Shot Hole Borer (PSHB) is an invasive wood-boring beetle that attacks dozens of tree species in Southern California, including commercial avocado groves, common landscape trees, and native species in urban and wildland environments.

PSHB spreads a disease called Fusarium Dieback (FD), which is caused by pathogenic fungi. Trees that are FD-susceptible may experience branch dieback, canopy loss, and, in some cases, tree mortality.

Like PSHB, Kuroshio Shot Hole Borer (KSHB) is an exotic Euwallacea species that also vectors Fusarium Dieback. Both beetles are present in Southern California but are concentrated in different regions. See their known distribution here.


  • New Online Training

    Invasive shot hole borers (ISHB) are a pest and disease complex potentially affecting over 200 tree species, but posing a strong risk to box elders, sycamores, and other riparian and urban trees, as well as being a nuisance pest for avocado. The beetles...

    By Sabrina L. Drill
    Author - Natural Resources Advisor
  • 2019 Workshop in San Luis Obispo

    We're moving north, and holding a training workshop with CalFire ongoldspotted oak borer and invasive shot hole borers May 9th, 2019 in San Luis Obispo! This workshop will address biology, identification, surveillance, and management of infested...

    By Sabrina L. Drill
    Author - Natural Resources Advisor
  • PSHB in the News Again

    Invasive shot hole borers are in the news again. Our collaborator, Greg McPherson with the US Forest Service, has just released a new estimate of the potential damage polyphagous and Kuroshio shot hole borers may cause as the spread across the...

    By Sabrina L. Drill
    Author - Natural Resources Advisor

www.pshb.org was made possible by support from the US Forest Service Forest Health Protection Program, UC Riverside, Orange County Parks, the California Avocado Commission, and the work and in-kind support of federal, state, and local partners. 

Latest News

So Many Shot Hole Borers: New research charts four nearly identical species

Entomology Today

Jiri Hulcr & Jackson Landers, 01/07/2019

Reducing the Spread of Invasive Pests in Cut Wood/Managing ISHB in Southern California (2 articles)

UC IPM Green Bulletin

California Firewood Task Force/Beatriz Nobua-Behrmann, Fall 2018

Beetle Mania: The Nasty Insect that is Killing the Trees of Johannesburg

Yale Environment 360

Adam Welz, 10/16/18

Tips from Disney expert: Horticulture Team Battles the Beetle

Orange County Register

John Kabashima, Ph.D. 9/23/18


Tiny Beetle Killing Trees, Ups Fire Risk in San Diego

NBC 7 News

May Tjoa 7/6/18

Final image for sd article 7.11.18


Tree Will Need Replacing with More Resilient Species

NPR - Market Place

Aaron Schrank 6/7/17


Southern California Trees Threatened by Borer Beetles

California Audubon

Sandy DeSimone 6/6/17





Find out more by following this link: 



Get PSHB Updates

Join the ISHB Email List
Online Training

ISHB on-line training!  The course is  served by the eXtension national online learning platform (and users will need to create a free account). 

ISHB Detection & Management Assessment

Before reporting infestations, take this online assessment to see if your tree is suffering from ISHB damage.

Upcoming trainings
Event Name Date