Sudden Oak Death: A Devastating Plant Disease to Watch For

Sudden Oak Death (SOD), caused by the fungus Phytophthora ramorum, was first discovered in California, killing large numbers of oaks. It appears to kill an oak in just weeks. In 2001, it was found in southwest Oregon; later in British Columbia, Oregon, and Washington on camellias and rhododendrons in nurseries. Infected nursery stock was destroyed, but vigilance is essential.

Susceptible Plants

Oregon myrtle and rhododendron are carriers. SOD affects 60+ species, including Douglas fir, oaks (except white oaks), witch hazel, yew.

Transmission

Spread by windblown rain and infected nursery stock.

Symptoms

Leaf spotting (camellias), rapid twig/branch dieback (madrones), girdling cankers that quickly kill (oaks, tanbark oak). Avoid buying plants with unhealthy leaves.

Treatment

Prune out and burn branches with leaf spotting or twig dieback. No viable chemical control yet; research ongoing.

Information

Visit www.suddenoakdeath.org or call 888/703-4457, or contact your county cooperative extension office.