What causes sudden oak death?
It’s caused by a fungus-like brown alga called Phytophthora ramorum (phy-TOFF-thoruh ruh-MOR-um), which was identified in 2000 by University of California researchers at the Berkeley and Davis campuses. P. ramorum is related to the organism that caused the Irish potato famine. It may have entered the United States on imported nursery plants. Does this organism affect other trees and plants? Yes, in addition to coast redwood and Douglas fir, the current host list includes: California black oak, coast live oak, Shreve oak, tanoak, rhododendron, California bay laurel, big leaf maple, madrone, manzanita, huckleberry, California honeysuckle, toyon, California buckeye, and California coffeeberry, among many others. P. ramorum also has been found on common nursery plants in Europe and Canada. What are the symptoms of sudden oak death and related diseases? In oaks, the first symptom is typically a bleeding or oozing of thick, dark reddish-brown sap from the trunk. With tanoaks, the first sympt
