Polyphagous Shot Hole Borer (PSHB) at UC Irvine

Tuesday, November 1, 2016– The Polyphagous Shot Hole Borer (PSHB) and plant disease known as Fusarium dieback persist within UCI’s urban forest and natural areas and continue to spread across the region. A recent survey at UCI identified 1,500 trees with PSHB and Fusarium dieback within the campus core and student housing areas. Approximately 1,000 trees have also been identified with the beetle-disease complex in University Hills. Shot Hole Borers (including the closely related Kuroshio Shot Hole Borer) have now spread throughout Orange, San Diego, Los Angeles, Riverside, San Bernardino, and Ventura counties and their occurrence has been recently confirmed in Santa Barbara County. The beetle-disease complex has caused severe damage to a wide variety of trees within both urban forests and natural areas. 

UCI continues to manage the PSHB beetle-fungus complex on campus through implementation of Best Management Practices (BMPs) developed collaboratively among UCI, the University of California’s Division of Agriculture and Natural Resources (ANR), and UC Riverside scientists. As findings from research on our campus and regionally have become available, UCI is updating its BMPs for surveying, assessment, treatment, and removal of infected trees. 

Approximately 500 trees on campus that were severely damaged by PSHB were removed last year, and 150 additional trees have been identified for removal based on recent campuswide surveys and assessment. Tree removals will move forward this month, and campus staff will continue to work with stakeholders in impacted campus areas where a significant number of trees or extremely large trees require removal. 

The campus is continuing its reforestation efforts with the goal of replacing the tree canopy lost to the beetle-fungus complex with a diverse range of species selected based on potential resistance to PSHB. The first phase of reforestation occurred last spring and replaced the tree canopy lost in the most heavily impacted areas of campus. The second phase of reforestation will be implemented this winter and will replace approximately 150 trees lost in the central academic core. 

Information regarding the status of the regional PSHB infestation, including the current geographic range of the infestation and steps to take when reporting PSHB infected trees, is available at http://ucanr.edu/sites/socaloakpests/Polyphagous_Shot_Hole_Borer/ and http://eskalenlab.ucr.edu/links.html.

University Hills residents who have questions regarding trees in common areas or private property in University Hills should contact Andrew Herndon at Andrew.Herndon@icha.uci.edu.

Regional beetle infestation prompts removal of UCI trees – UCI News April 17, 2015
Scientists fight to save iconic UC Irvine trees from invasive beetle – 89.3 KPCC July 21, 2015

Read more about the September 9 Polyphagous Shot Hole Borer (PSHB) Workshop:

Thank you for your participation in the September 9 Polyphagous Shot Hole Borer (PSHB) Workshop. More than 160 attendees from diverse backgrounds participated. The workshop provided an opportunity to better understand the regional impact of PSHB and its potential management.  A white paper with recommendations for a regional response will be prepared as a result of the workshop.

 Presentation Slides

Akif Eskalen – Current Studies on PSHB and Fusarium Dieback

Timothy Paine  – PSHB: What do we know about it?

Richard Demerjian – PSHB on the UCI Campus

Monica Dimson – PSHB in Orange County Open Spaces

John Kabashima – The Regional Impact of PSHB and Emerging Tree Pests

Dele Ogunseitan – PSHB: Public Health Considerations

UCI and the University of California’s Division of Agriculture and Natural Resources are co-hosting a regional workshop on the Polyphagous Shot Hole Borer (PSHB), a tiny non-native beetle that has invaded Southern California and is currently threatening tens of thousands of trees throughout the region. This invasive species is quickly reaching epidemic proportions and has widespread environmental, economic, and esthetic implications.

The workshop will feature speakers involved at the forefront of researching the PSHB, potential responses, and urban forest management. It will provide an opportunity for scientists, land managers, public agencies, and practitioners to better understand the regional impact of PSHB and its potential management.

tree trunks eaten by bugsUCI News

Regional beetle infestation prompts removal of UCI trees: Pests have been gaining ground in Southern California for as many as three years – Read More

University of California, Division of Agriculture and Natural Resources

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 pathogenic fungus (Fusarium euwallacea), as well as other fungal species that may to help establish the colonies. The PSHB attacks many species of trees, but some trees are resistant to the fungus it carries. – Read More

University of California, Riverside – Eskalen Lab

Research applied and focused on the identification and epidemiology of branch, trunk, and root pathogens of subtropical plants: avocado, citrus and landscape trees. – Read More

8:30 - 9:00 a.m.Registration and NetworkingUCI staff
9:00 - 9:15 a.m.Introduction and WelcomeTravis Huxman
Professor, Ecology & Evolutionary Biology
Director, UCI Center for Environmental Biology
UC Irvine
9:15 - 9:40 a.m.Current Studies on Polyphagous Shot Hole Borer/ Fusarium DiebackAkif Eskalen
UC Cooperative Extension Specialist and Plant Pathologist
Department of Plant Pathology and Microbiology
UC Riverside
9:40 - 10:05 a.m.PSHB: What do we know about it?Timothy D. Paine
Professor and Entomologist
UC Riverside
10:05 - 10:20 a.m. 


10:20 - 10:55 a.m.UCI Status Report and Management PlanRichard Demerjian
Director, Environmental Planning and Sustainability
UC Irvine
10:55 – 11:10 a.m. 


11:10 – 11:35 a.m.PSHB in Orange County Open SpacesMonica Dimson
Staff Research Associate
UC Cooperative Extension
11:35 a.m. – noonThe Regional ImpactJohn N. Kabashima
Environmental Horticulture Advisor, Emeritus
UC Cooperative Extension
Noon – 1:00 p.m. 


1:00 – 1:45 p.m.Public Health ConsiderationsOladele Ogunseitan
Professor and Chair, Department of Population Health & Disease Prevention
Program in Public Health
UC Irvine
1:45 – 2:00 p.m. 


2:00 – 2:30 p.m.Local PartnershipsTodd Spitzer
Third District Supervisor
Orange County Board of Supervisors
2:30 – 3:00 p.m.Next Steps and Wrap-UpTravis Huxman

Please register online at:



The $25 per person workshop fee includes lunch, refreshments and reserved parking.

Important Deadline

Please register no later than Thursday, September 3, to ensure your choice of lunch and arranged parking.

The Student Center Parking Structure is located on the corner of West Peltason Drive and Pereira Drive.

Enter the Student Center from Pereira Drive opposite the parking structure. Take the stairs directly ahead to reach level 2. The Crystal Cove Auditorium is on the left.


Parking costs are included in the registration fee. Present your name to the booth attendant at the kiosk to receive your pass.

UCI Student Center & Event Services
A311 Student Center, Irvine, CA 92697-2050

Workshop Contact:
Katie Babcock
(949) 824-6316

Media Contact:
Brian Bell
(949) 824-8249