"The furtive, runaway disease earned its name by killing oaks from the inside. After about a year, infected oaks succumb to the disease. Sudden oak disease has killed thousands of trees — most vulnerable is the coast live oak — in 14 counties from Monterey to Humboldt.
the leaves of the bay tree have become a host for Phytophthora ramorum, the microbe that causes sudden oak death syndrome. Scientists believe Phytophthora ramorum was introduced to California several years ago from foreign rhododendrons grown or sold in local nurseries.
Once the microbe finds a home on a bay tree leaf, usually during spring, it will swim downstream on rainwater to the tip of the longish leaf. Once there, it "burns" the leaf's tip, giving it the look of burned toast and an odd-looking yellow halo. When these leaves rub up against an oak, they can pass on the microbe, which then burrows into the oak's trunk and begins its dirty work. The bay trees, however, go on living unharmed."
