St. Paul, MN (July 11, 2002)—In the few years since it was first discovered in 1995, Sudden Oak Death has had a devastating impact on the west coast, sending plant health scientists scrambling to find a way to control it. The disease has already killed tens of thousands of oaks along the coast of California (10,000 in Marin County alone and virtually all the tanoaks in Big Sur), infected a growing number of other plant species, and, according to the U.S. Forest Service, has altered California’s forest ecosystem for years to come. Meeting July 31 in Milwaukee, Wisconsin, plant scientists will present new research into the nature of how the disease appears to be spreading. Scientists from the U.S. Forest Service, the USDA, and the American Nursery and Landscape Association will discuss current efforts to contain it.
“This is an organism that has the potential to impact entire plant communities,” says Matteo Garbelotto, a plant pathologist at the University of California, Berkeley and a key researcher on Sudden Oak Death. While oak trees are the disease’s most obvious victims, scientists have discovered that the disease is infecting a growing list of other plant species as well. Unlike the oaks however, these plants do not die as a result of their exposure, but become hosts, helping the disease to spread. As a result, many of these host plants become substantially weakened, making them more susceptible to other diseases and upsetting the natural balance of the ecosystems in which they live.
Even more disturbing is the discovery that the biology of this disease is unusual, making it seemingly more virulent. Says Garbelotto, “The way this pathogen appears to be spreading is quite atypical for an organism belonging to the genus Phytophthora: this microbe has an aerial component and uses a range of alternate hosts to infest forest stands.” And this, say scientists, is cause for concern since standard types of disease control may not work well with this particular disease. Although they acknowledge that weather conditions unique to California’s coast have probably played a significant role in the disease’s ability to gain such a strong foothold in the region, no one is willing to say that Sudden Oak Death won’t spread to other parts of the U.S. with the same results. Preliminary results show that susceptible plant species are present throughout the continent.
The fact that Sudden Oak Death was recently discovered in Oregon has created an even greater sense of urgency and there is now a federal quarantine restricting the trade of known carriers and requiring strict inspection and monitoring of plant shipments from infected areas. The U.S. Forest Service plans to launch a pilot survey this year to look for signs of the disease in the Northwest and along the East coast. Says Borys Tkacz, national program leader with the US Forest Service’s Washington D.C. office, “It seems the more we look, the more we find. But it’s hard to know whether it’s really spreading that quickly, or that we’re now just finding it because we know what to look for.”
The special session on Sudden Oak Death will be held from 8:00 a.m. to 12:00 p.m., Wednesday, July 31, as part of the APS Annual Meeting in Milwaukee, WI, July 27-31. Complimentary registration is available for reporters and science writers. The American Phytopathological Society (APS) is a nonprofit, professional scientific organization dedicated to the study and control of plant diseases, with 5,000 members worldwide.