Mystery Oak Disease
Deadly spores could ravage country’s trees ; Pathogen that’s killing Calif. trees on the move
By John Ritter, 9 Apr 2002, USA Today
SAN FRANCISCO — On the rolling hills and low mountains of coastal Northern California, green and lush now after winter rains, live oaks, tan oaks, black oaks and madrones have been dying for more than two years. A mysterious microscopic organism that causes Sudden Oak Death has been found on a widening list of trees. Even the stately redwood, a California icon as well as a valuable timber product, may be vulnerable.
But a far more troubling scenario is gaining currency among plant pathologists and federal regulators: that the disease will make its way out of California and infect the forests of the interior USA with potentially disastrous results.
That seemed unlikely until the organism suddenly appeared last fall on a maple tree in the foothills of the Sierra Nevada more than 100 miles away. If confirmed by tests on more samples, that would mean it had somehow moved east from the Pacific Coast across the agricultural Central Valley — signaling a highly aggressive pathogen capable of adapting to new environments and different trees.
Dutch elm disease and chestnut blight, scourges that virtually wiped whole species from the American landscape in the last century, began as localized infestations. “Something like this could be transported on a piece of luggage from one place to the next,” says Jim Skiera, associate executive director of the International Society of Arboriculture in Champaign, Ill. “If it’s as virulent as they say, it could be devastating. It could have a huge economic impact if it hit multiple species.”
Lab tests already have confirmed that the Sudden Oak Death pathogen, Phytophthora ramorum, kills northern red oak, the dominant hardwood in the U.S. timber industry and a preferred species in furniture, flooring, cabinets and architectural interiors.
