Since its discovery in the mid 1990s, the pathogen that causes Sudden Oak Death (SOD) has been the focus of an intensive research effort designed to understand its biology and to develop management strategies that prevent or reduce the spread of this disease.

Described as Phytophthora ramorum in 2000, this emerging and probably exotic pathogen causes a lethal canker disease in several oak (Quercus) species and tanoak (Lithocarpus densiflorus). The disease has reached epidemic levels in many coastal forests of California and southwestern Oregon. In addition to causing mortality in oak and tanoak species, P. ramorum causes non-lethal leaf and twig infections on over 25 plant species, and these taxa are thought to play important roles in the spread and persistence of the disease (especially bay laurel, Umbellularia californica).

Other Sudden Oak Death Research Projects::

Learn what you can do to prevent the spread of Sudden Oak Death.

To learn more about SOD visit California Oak Mortality Task Force.