Posts Tagged: polyphagous
Invasive Spotlight: Shot Hole Borers
Small beetles are causing big problems in Southern California. Two closely related species, the...
Watch Out For Invasive Shot Hole Borers on Your Landscape Trees
Watch out for these insects! Invasive shot hole borers (ISHB) represent two related species of beetles (polyphagous and Kuroshio) in the genus Euwallacea. Both spread fusarium dieback, a disease that restricts the flow of water and nutrients in the tree, resulting in dead branches, dropped limbs, and even death. Over 60 species of native and non-native ornamental trees and avocados in Southern California are susceptible the ISHB/fusarium dieback complex.Examples of known hosts of the ISHB/fusarium dieback complex include: Box Elder (Acer negundo), Avocado (Persea americana), English Oak (Quercus robur), Valley Oak (Quercus lobata), California coast live oak (Quercus agrifolia), Big leaf maple (Acer macrophyhllum) silk tree (Albizia julibrissin) Liquidambar (Liquidambar styraciflua), Coral tree (Erythrina coralladendron), California sycamore (Platanus racemose), Blue Palo Verde (Cercidium floridum), Purple orchid tree (Bauhinia variegate), Kurrajong (Brachychiton populneus); and many species of Acacia.
The beetles are native to Southeast Asia and were likely introduced into California in shipped goods, wood products, or packaging. While tiny (about the size of a sesame seed), they are prolific, tunneling into host trees and living and reproducing in galleries while feasting on the disease-causing fungus they spread from tree to tree. Females are black and much more common than the small wingless brown males, which are rarely found.
While the initial infestation occurred in Los Angeles County in 2003, beetles travel about 12 miles a year and have now spread fusarium dieback into Orange, San Diego, Riverside, San Bernardino, Ventura, and Santa Barbara Counties. Orange County alone has spent millions of dollars removing infested trees and managing the spread of the ISHB/fusarium dieback complex.
Identifying ISHB in a timely way is essential to reduce damage and slow its spread. Look for round borer entry holes about the size of the tip of a medium ballpoint pen. Staining, gumming, discoloration of wood beneath the bark, and/or frass (sawdust-like material) are other common signs and symptoms. There may also be white powdery exudate around beetle entry holes. Keep in mind that there are many other disorders that have similar symptoms. For example, other fungal diseases produce exudate and staining and other types of borers leave entry holes of various shapes and sizes.
To date, no effective control measures have been found once trees are infested, although entomologists and plant pathologists from the University of California, The USDA Forest Service and other agencies continue to research viable integrated pest management options including biological control.
To prevent and/or reduce spread of ISHB/fusarium dieback:
- Bring only ISHB-free greenwaste (used for mulch and soil amendments) and firewood onsite. Both products can harbor ISHB which can persist for months.
- Treat infected wood onsite whenever possible. Wrap or completely cover wood that cannot be immediately treated and wood that is moved offsite for treatment elsewhere.
- Chipping infested wood to 1 inch or less can kill 95% of the beetles, while solarizing it using a clear tarp eliminates both ISHB and spores produced by the fungus. Logs can also be solarized. Composting is another option that, when done correctly, can kill both beetles and fungal spores.
- Untreated logs, branches, or woodchips infested with ISHB should not be used for firewood or mulch.
- Remove stumps as well as dead trees.
- Follow International Society of Arboriculture pruning standards and never top or flush cut trees which leave open wounds.
- Spray a 70% ethanol solution on equipment and tools since fusarium fungi can adhere to both.
- Keep trees healthy (water mature trees deeply and infrequently, avoid over or under-fertilization, etc.).
- Monitor susceptible tree species often to identify damage as early as possible. Useful detection and reporting tools and more detailed information on the ISHB/fusarium dieback complex can be found here: ucanr.edu/sites/pshb
For more detailed information on the ISHB/fusarium dieback complex, please visit these websites: https://ucanr.edu/sites/pshb/ https://www2.ipm.ucanr.edu/agriculture/avocado/polyphagous-shot-hole-borer-and-kuroshio-shot-hole-borer/ https://cisr.ucr.edu/invasive-species/polyphagous-shot-hole-borer https://californiareleaf.org/pests/
Shot Hole Borer Training
Come Learn About Field Identification of Invasive Shot Hole Borers
We're holding two early December trainings on invasive polyphagous and Kuroshio shot hole borer biology, identification, surveillance, and management of infested trees and downed wood. We'll cover these topics in the classroom, then head outside to see infested trees and learn how to identify signs of shot hole borer damage, set up a monitoring program, and sample trees.
$30.00 Registration fee includes lunch, a ISHB Field Guide, and ISHB Demonstration Kit
Continuing Education Units from DPR have been requested, check back for updates.
Speakers include Sabrina Drill, UCCE Natural Resources Advisor; Bea Nobua-Behrmann, UCCE Research Scientist; Kim Corella, Forest Pest Specialist, CalFire; and Paul Rugman-Jones, Research Entomologist, UC Riverside.
Ventura County - Ojai - Dec.6
Meiners Oaks (Ojai) Class & Field Training at Saint Thomas Aquinas Church
Thursday December 6, 2018, 10am – 2:30pm
Los Angeles County - Gardena - Dec. 7th
Gardena Class & Field Training at Gardena Moneta Mason Lodge & Gardena Willows Wetland Preserve
Friday December 7, 2018, 10am – 3:00pm
field id
Managing Invasive Shot Hole Borers in Southern California
[Originally published in the Fall 2018 issue of the Green Bulletin. Modified slightly from...
What's Happening With Shot Hole Borer?
This is the most recent activity summary of a group of organizations working on the Invasive Shot Hole Borers and their associated fungal symbionts. This pest/disease complex affects avocado along with a large number of native and landscape plants in California, as well as in other parts of the world (http://ucanr.edu/sites/pshb/; http://ucanr.edu/sites/pshb/files/238251.pdf):
Invasive Shot Hole Borers
Quarterly Situation Report
January through March 2018
Executive Summary
Overview
Education, outreach, and monitoring activities were robust during the cool damp winter months of 2018. Infestations continued to dominate Orange, San Diego, and Los Angeles counties, with lesser activity in Ventura and Santa Barbara counties. The need for funding of research, education, outreach, and waste management associated with ISHB was brought to the attention of state governance. Preventative efforts to increase awareness of ISHB in unaffected counties continued. Collaborative efforts of numerous agencies, educational institutions, and non-profit groups resulted in the successful efforts listed below.
Statewide
The two-day Invasive Species Summit was held in the State Capitol for legislators and their staff to learn about environmental pressures and costs created by these species statewide. Three pieces of proposed legislation were written either specific to or with components addressing ISHB. They are: AB 2054 (Gonzlez Fletcher), AB 2166 – California Farm Bill, AB 2470 (Grayson) – Invasive Species Council.
The Statewide SHB Network convened telephonically to discuss ISHB, spread, threat, and help educate those in unaffected counties. An ISHB presentation was given at a statewide horticultural convention in northern California.
The triennial California Native Plant Society Conservation Conference was held near Los Angeles International Airport. ISHB was addressed at a pre-conference invasive species workshop, throughout the conference by tabling and poster session, and during the Invasive Species Session.
Regional
UCCE San Diego helmed a two-part GSOB/ISHB-FD webinar, along with other UCCE and CALFIRE collaborators. The first installment streamed in March.
UCCE San Diego began work on an online ISHB survey assessment tool that will be accessible when completed on PSHB.org. This feature will help the public determine if tree symptoms may be due to an ISHB infestation. An added component will allow UCCE to monitor reporting. The decision tree that is part of the assessment takes the reporter to part of the site whereby photos can be submitted if the tool determines a probability of ISHB infestation. This tool will be completed, tested, reviewed, and posted to the website by summer 2018.
San Diego County
- Two ISHB public educational events were presented
- Buy It Where You Burn It campaign distributed literature countywide
Orange County
- Four ISHB public educational events were presented
- Numerous trap and monitoring sites are established throughout the county primarily in wildlands and parks
- Orange County Waste and Recycling learned 28% of all trees at Prima Deshecha Landfill in San Juan Capistrano are infested with ISHB/FD or Botryospaeria. Most of the vegetation at this site is comprised of native species
- A post-incident GSOB/ISHB reconnaissance was conducted in Weir Canyon, where the Canyon II Fire burned in autumn 2017
- Orange County Parks continued to track tree losses and costs associated with ISHB infestations on its properties. An economic report was publicly released
Los Angeles County
- Three ISHB public educational events were presented
- A funding request was submitted to County governance to continue the ISHB trapping program coordinated by the Resource Conservation District of the Santa Monica Mountains
- The Huntington continued monitoring and green waste processing at the 207-acre facility. An ISHB trapping trial by principal investigator at UC Riverside was initiated that utilizes castor wood as the attractant
Ventura County
- Twenty-six traps are established and monitored in the Santa Clara River watershed extending from the estuary to Piru
- Fifteen traps are established and monitored in the Ventura River watershed. This number is down by two after being lost during the Thomas Fire
- A new infestation was identified in the City of Santa Paula proximal to a known infestation in the Santa Clara River
- One ISHB educational event was presented to Master Gardeners
Santa Barbara County
- Seven traps are being monitored in Montecito and the City of Santa Barbara
- Three traps in Montecito were lost from the January debris flow disaster
- One ISHB educational event was presented to Master Gardeners
San Luis Obispo County
- One ISHB educational event was presented to Master Gardeners
Articles:
A. Raver. The tiny menace. Landscape Architecture Magazine. March 2018.
https://landscapearchitecturemagazine.org/2018/03/13/the-tiny-menace/
Images:
Shot Hole Borer galleries, cottonwood
Shot Hole Borer entry point, sycamore. Curtis Ewing, CAL FIRE
shot hole borer galleries
shot hole borer sycamore