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Sudden Oak Death

Less than ten years ago, on the west coast from central California to southern Oregon oak trees were taking a hit from what is now called "sudden oak death". Literally tens of thousands of trees were affected as these seemingly healthy trees died. California black oaks, live oaks, shreve oaks and tanoaks have been affected.

The organism responsible for the sudden oak death is a new fungus - like species called phytophthora ramorum.

The interesting part is this organism phytophthora is a member of the destructive genus known as the water molds. The most familiar being the famous for the great Irish potato famine.

Sadly, trees may show no sign for three years, when they will start showing cankers that are on the trunks.

The disease then will invade and kill the cambium layer of the tree. This will prohibit water and nutrients for growth and the tree dies.

Still other trees do show some leaf spot and twig die back hosting the pathogen - P. ramorum. This is happening on about 24 west coast natives plants. Among them are bay laurel, big leaf maple, redwood, manzanita, madrone , and the douglas fir. In Europe, they too have the pathogen on vibrunums camellias, and rhododendrons.

How is this being controlled? There may be some solutions with fungicide phosphanate. This is already being used for other plants affected by phytophthora.

Although basically a west coast problem, steps have been taken by federal, state, and international quarantines to at least prevent people from spreading the disease with individual plant travel and purchase.

2006 The New Review Online (Salem, OR)

         University of California: Sudden Oak Death Facts

2006: For more information and updates: www.suddenoakdeath.org

US Forest Service: http://www.na.fs.fed.us/sod/ 

US Invasive Species website: http://www.invasivespecies.gov/profiles/sod.shtml