The fungus that causes Sudden Oak Death, a virulent disease which has killed tens of thousands of trees in northern California since 1995, was recently discovered on the UC Berkeley campus, school officials reported on Wednesday.
According to Jim Horner, campus landscape architect, the pathogen Phytophthora ramorum was discovered to have infected a bay laurel tree, a buckeye and a rhododendron near the university’s Faculty Glade.
The discovery, made by Dr. Matteo Garbelotto of the College of Natural Resources, is the first time the fungus has been found in the East Bay lowlands. In August, several live oak and bay laurel trees bordering Crow Canyon Boulevard, in the hills outside Castro Valley, were found to be suffering from the disease.
Some experts fear that the discovery could mean the fungus is already widespread in the Berkeley area.
“The fact that they found this on campus means that it’s most likely already in and around Berkeley – probably up in the hills there,” said Bruce Hagen, an urban forester with the California Department of Forestry who has studied Sudden Oak Death extensively.
Garbelotto, one of the leading researchers on the disease, said he expected this to be the case.
“The most likely explanation is that it’s widespread in the county but is not yet killing the oaks,” he said. “The other would be that this pathogen was introduced in particular spots, by birds or some other carrier, and the campus happened to be one of them.”
In addition to oaks, the fungus can live and spread on a number of different species of trees and shrubs, including madrones, manzanitas, huckleberries and certain maples.
Many of these species are not affected as severely as oaks by the disease. The fungus may just infect their leaves and not their trunks, as in the case of oaks. The campus’ infected plants on campus all showed symptoms in their leaves.
Garbelotto said those species may manifest the symptoms of infestation long before it shows up in neighboring oak trees. Non-oaks may show signs of infection just 72 hours after exposure to the fungus, whereas the disease can gestate in oak trees for months or even years before any symptoms appear.
Garbelotto said he expects to begin testing trees around the city very soon.
“I have received some reports of suspicious trees in the Berkeley hills,” he said..
Many experts warned, however, that the disease is nearly impossible to identify on sight. Garbelotto said samples from the trees on campus were tested three times before a diagnosis was confirmed.
“The thing about Sudden Oak Death is that there are many other diseases that look like it,” said Jerry Koch, a forester with the city. “That’s why you have to have a lab test to confirm that a tree has this particular fungus.”
Local agencies involved with the disease have been preparing for an onslaught of Sudden Oak Death around Berkeley, but they have not developed a detailed plan to respond if it does strike.
“We’re in the early stages of the research as to how this spreads and what we can do to slow it down,” said Koch, who had attended a seminar on the disease in September.
Koch said the only immediate action the city could take is to determine if any trees are infected and isolate them. He said if more cases are found, the city would have to make sure that chips from removed or trimmed trees not be moved to a different location.
Ned MacKay, spokesperson for the East Bay Regional Parks District, said coincidentally, a parks district workshop on Sudden Oak Death, which had been planned for many weeks, was held Wednesday at the Oakland Zoo.
According to MacKay, the EBRPD had just issued a new policy to help contain Sudden Oak Death if it is found in the park system. The policy banned the cutting of downed logs into firewood, so that people wouldn’t be tempted to carry it off and unwittingly spread the disease.
Lisa Caronna, director of the city’s Parks and Waterfront department, said her department had no immediate response to the discovery of the disease.
“We’re going to be implementing whatever best practices that are recommended by the experts,” she said.
Garbelotto said he would be hanging informational fliers around the campus, warning students not to take plant material from the campus into their homes.
“Students need to be responsible and not to bring the pathogen into their neighborhood,” he said.
Maggie Kelley, director of monitoring for the California Oak Mortality Task Force, said citizens should be on the watch for the disease in their communities.
“The risk is pretty high,” she said. “Once this gets established in an area, it can spread pretty quickly. In Berkeley, the conditions are right, and the host materials are there.”
“We always encourage people to look out, but we also want them to be educated about the look-alike diseases out there.”
Concerned citizens may learn more about the disease on the Oak Mortality Task Force’s web site, www.suddenoakdeath.org. If you have a tree that you believe may be afflicted, read about the symptoms particular to that tree. If you still believe the tree might carry the disease, contact the Natural Resources Advisor for the UC’s Cooperative Extension program at (408) 299-2635.