- Author: Chris M. Webb
Over the last 10 years, the Goldspotted Oak Borer (GSOB) has killed approximately 80,000 oak trees in San Diego County – including many large trees that were hundreds of years old.
To date GSOB has caused significant economic, ecological, cultural, and aesthetic losses in San Diego County. The costs of dead tree and infested wood alone is staggering.
GSOB (Agrilus Auroguttatus) is an invasive insect in California. Because it is a non-native pest there are not natural defense mechanisms to keep this insect in check. There is concern among experts that GSOB will continue to move north through California. Susceptible oak species are: coast live oak, California black oak, and canyon live oak.
It is highly suspected that GSOB entered California in firewood. GSOB larvae can live under the bark of dead oaks for over a year before exiting as adults. It is likely GSOB has spread so quickly in San Diego County via firewood movement. Because of this, it is extremely important to be mindful of where your firewood comes from. The movement of infested firewood could easily establish this destructive pest throughout the state.
To learn more about GSOB, or to get involved in preventing its spread, please see the gsob.org website.
And remember, to protect California’s Forest – Buy and Burn Local Firewood! Don’t move it around!
- Author: Chris M. Webb
UC Davis Arboretum All-Stars are plants tested by University of California horticultural staff. These plants are tough, reliable, easy to grow, don’t need a lot of water, have few problems with pest or diseases and have outstanding qualities in the garden. Many support native birds and plants.
Karrie Reid, UCCE Environmental Horticulture Advisor for San Joaquin County, performed trials on potential UC Davis Arboretum All-Stars as part of her Master’s Thesis work. She is an enthusiastic proponent of beautiful plants that require little water and even fewer chemical inputs.
Karrie will be at Thousand Oaks Goebel Center on Saturday, November 12 from 9:45 to 11:30 am. To find out more about this fabulous, free educational opportunity, or to register please see our Master Gardener website.
- Author: Chris M. Webb
Channel Island National Park Visitor Center is located in the Ventura Harbor. The center allows visitors to view displays, exhibits, and watch a movie that capture the life and character of each island.
On weekends and holidays National Park Rangers offer a variety of free programs to share additional information about the islands with the public.
UC Cooperative Extension Master Gardeners are part of this fun and educational center. They are busy in the Native Plant Garden, which is located at the front of the visitor center. Pulling weeds and pruning are weekly tasks. Design, site preparation, planting, and irrigation installation and repairs are some other regular activities in the garden.
Master Gardener volunteers also identify and research various native plants. The garden is extra special as it showcases plants endemic to the Channel Islands in addition to plants native to mainland Southern California. The endemic island plants are propagated from seeds collected on the islands and grown in the garden greenhouse.
Next time you are at the Ventura Harbor, be sure to stop by the Visitor Center and see this beautiful and unique garden!
- Author: Chris M. Webb
The California Oak Mortality Task Force (COMTF) works to manage Sudden Oak Death (SOD) in California. Those working with the task force include: research and educational institutions; public agencies; non-profit organizations; and private interests.
SOD is caused by the pathogen Phytophthora ramorum. It affects oaks and other host plants and trees. This pathogen thrives in cool, wet climates. “In California, coastal evergreen forests and tanoak/redwood forests within the fog belt are the primary habitat…Nurseries outside of these cool, moist areas often create microclimates which mimic the preferred environment of P. ramorum and allow it to grow and spread far from the coast.” While there is no cure, there are preventative measures that may protect plants.
The goals of COMTF are to:
- Minimize the impact and spread of Phytophthora ramorum on natural, agricultural, and human communities
- Coordinate an integrated response by all interested parties to address Phytophthora ramorum
- Serve as liaison to local, state, national, and international groups
Their website is easy to navigate and is well written. In addition to the text there are plenty of photos, maps, and videos to further educate site visitors about this disease.
To date there has been no confirmed SOD in Ventura County; however, there is much interest in this subject locally. Please visit the COMTF site to learn more.
- Author: Chris M. Webb
Poison oak is the most hazardous plant in California. It gained this distinction due to the annual number of working hours lost from allergic contact dermatitis caused by poison oak. The allergic reaction occurs in 80-85% of the population. It can cause skin irritation, itching and blisters.
Transmission of the allergen can occur by direct contact with the plant at any time of year; by touching contaminated clothing, tools, or animals; or by breathing the smoke caused by burning poison oak. The smoke is extremely hazardous. Inhaling this smoke can cause severe respiratory irritation. Never purposely burn poison oak.
A native of Western North America, poison oak (Toxicodendron diversilobum) can thrive in a variety of settings. It can grow as a shrub or as a climbing vine. Leaves normally consist of three leaflets, but not always. Leaves can be glossy or dull. In the spring these plants produce flowers and in the summer berries. In fall foliage turns from green to orange and red.
To find out more about this plant including: impact on livestock, treating allergic contact dermatitis, biology, and management, please see UC ANR’s Poison Oak Pest Note.
