Drought is decreasing but not defeating the pathogen that causes sudden oak death, according to a citizen science-assisted survey conducted this spring by a UC Agriculture and Natural Resources forest pathologist.
Results of the 2015 Sudden Oak Death Blitz survey reveal coastal mountain infestations in areas such as Big Sur (19% infection), the Santa Cruz Mountains (13% infection), and western Sonoma County (12% infection) remain high despite an overall decline in infection rates from 4.4% to 3.7% across California's 15 infested counties.
Sudden oak death (SOD) symptoms have been seen in Alameda, Contra Costa, Humboldt, Lake, Marin, Mendocino, Monterey, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano,...
- Author: Pamela Kan-Rice
If you have a real Christmas tree, University of California pest management experts ask that you to recycle the tree to prevent the spread of insects and diseases that may harm our forests and landscape trees.
“Invasive insects, diseases and plant seeds can move on cut Christmas trees and other holiday greenery,” said Janice Alexander, UC Cooperative Extension forest health educator in Marin County. “These pests can escape out into backyards and neighboring forests to begin new populations, upsetting the balance of our native ecosystems. Proper purchasing and disposal of holiday greenery helps reduce that...
- Author: Ann King Filmer
California’s renowned coast redwood trees, previously believed to be fireproof, are now more than four times more susceptible to wildfire injury in coastal forest areas infested with the sudden oak death pathogen. These redwoods are now as susceptible to wildfires as other trees.
Millions of trees, including tanoaks, coast live oak, California bay laurels, and many other forest species have been killed by sudden oak death in coastal areas of central and northern California, and Oregon. The pathogen, Phytophthora ramorum, was first linked to the massive tree death in the mid-1990s.
David Rizzo, professor in the Department of Plant...
- Author: Pamela Kan-Rice
Sudden oak death is a misnomer because it doesn't fell a tree like a lightning strike nor does the disease limit itself to oaks. Nonetheless, the moniker has stuck and UC scientists remain committed to containing the culprit.
UC, federal and state agencies and landowners in Humboldt County recently received national recognition for their collaborative efforts to halt the spread of sudden oak death. Kathleen Merrigan, U.S. Department of Agriculture deputy secretary, praised the partnership during her visit to Davis on May 16.
Yana Valachovic, UC Cooperative Extension advisor in Humboldt County, and
Sudden oak death (SOD) has been spreading among trees throughout coastal California and Oregon for the last 15 years. In that short time, the disease has infested 10 percent of California’s at-risk habitat and killed over a million tanoak and true oak trees, raising major concerns about the potential impacts of further pathogen spread. The disease is caused by the non-native pathogen Phytophthora ramorum.
Research by UC Cooperative Extension staff in Humboldt County shows that infection and oak mortality are only the beginning of the story, as the disease may increase forest fuels and put infested stands at higher risk of severe wildfire.
UC Cooperative Extension forest advisor