Plant disease threatens traditions of California tribes

From 2009:
Mary Larson Bishop gazes at the folds and peaks of the Santa Lucia Range with longing. "I used to go deep into the woods looking for herbs," says the Salinan tribal elder, who is known for her knowledge of medicinal plants such as yerba santa, traditionally used to heal skin inflammation. Now, she no longer roams the Central California coastal hills. "I'm afraid of bringing anything out of the woods that might spread to other trees," says Bishop. "I don't want to track that crud out of the hills."

The "crud" is Phytophthora ramorum, a minuscule waterborne mold that weakens and kills many species of native trees and plants. The pathogen, which causes both Sudden Oak Death and Ramorum blight, was first discovered in the mid-1990s. Since then, it has spread to 14 California counties along the Pacific Coast, and even to Washington and Oregon. It travels by clinging to boots, hands, pant legs and tires.

http://www.hcn.org/issues/41.12/cultural-blight