Sudden Oak Death is a tree disease caused by the fungus-like plant pathogen Phytophthora ramorum. First recognized in the mid 1990s, the disease kills some oak species (primarily coast live oak, Quercus agrifolia, and an oak relative, tanoak, Notholithocarpus densiflorus) and has had devastating effects on coastal forests in California and Oregon. The pathogen also infects rhododendrons, camellias, and other common horticultural plants, causing ramorum blight. In the UK and Ireland, the pathogen is causing extensive damage on Japanese larch (Larix kaempferi) in plantations.
Phytophthora ramorum was inadvertently introduced to California forests on nursery stock and, as an invasive species, is quarantined in over 60 countries with restrictions enforced on shipments of nursery stock and other host plant materials. For an introduction and background on Sudden Oak Death/P. ramorum read more here.
Relatives of P. ramorum, other Phytophthora species are damaging native and ornamental vegetation throughout California. Unintentional pathogen introductions are an acute concern for restoration of sensitive habitat where restoration nursery stock may serve as a pathway for pathogen introduction into rare, threatened or endangered species habitat. Read more about other Phytophthora species found in native habitats, native plant nurseries, and restoration sites here.
The USDA Forest Service, Pacific Southwest Region, State and Private Forestry, Forest Health Protection Program has submitted a Request for Pre-Proposals for 2023-24, due January 13, 2023. More information HERE.
P. ramorum (EU1 lineage) provisionally confirmed at new locations in Lincoln City, OR. Read more…
Polystichum munitum (common names western swordfern or sword fern) confirmed as a new P. ramorum host. Read more…
USDA APHIS updates Lists of Proven Hosts of and Plants Associated with Phytophthora ramorum with 81 more plant species. Read more…
SOD Blitz detections are at their lowest level in more than 15 years. Read more…
Recordings of the 2022 California Oak Mortality Task Force meeting held November 8-10th, are now available. Read more…
Help stop the spread of forest pests – including Sudden Oak Death – on firewood! Check out the website of the California Firewood Task Force.
See more information on increased mortality of Bay Area trees on our new web page, www.bayareatreemortality.org.
Calendar of Events
Recordings of the 2022 COMTF Virtual Annual Meeting: See AGENDA for full details and recordings from each day below.
Recordings of the 2021 COMTF Virtual Annual Meeting:
- Day 1 (9/21/21): short presentations on sudden oak death, Bay Area tree decline, and a review of other plant health concerns (1.5 hrs)
- Day 2 (9/22/21): COMTF Executive Committee reports (1.5 hrs)
- Day 3 (9/23/21): CalPhytos meeting with presentations concerning Phytophthoras in restoration and natural areas (2 hrs)
View more details on upcoming events in the latest newsletter…
The California Oak Mortality Task Force is a task force under the California Forest Pest Council.