Phytophthora ramorum is a plant pathogen that was accidentally introduced to the United States. This invasive microorganism has killed over a million trees in California and Oregon, and continues to spread to new areas. Diseased areas have been nationally quarantined to prevent further spread and more than ninety countries include...
Sudden Oak Death is the common name for a disease caused by Phytophthora ramorum, a previously unknown and recently introduced non-native pathogen.
• Phytophthora ramorum has killed hundreds of thousands of oak and tanoak trees in 14 coastal counties in California and hundreds of tanoak trees in Curry County, Oregon....
Alerts people who visit, live, or work in certain areas of Oregon and California about a serious plant disease called Sudden Oak Death, and asks them to take steps to prevent spreading the disease. Gives action steps, shows disease symptoms on various host plants, and gives numerous sources for more...
Alerts people who visit, live, or work in certain areas of California and Oregon about a serious plant disease called Sudden Oak Death, and asks them to take steps to prevent spreading the disease. Gives action steps, shows disease symptoms on various host plants, and gives numerous sources for more...
Published November 2009. A more recent revision exists. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Sudden Oak Death (SOD) is a plant disease caused by the water
mold Phytophthora ramorum. This organism causes disease in
more than 100 species of trees, shrubs, herbs, and ferns.
The phytopathogen Phytophthora ramorum (Werres, DeCock & Man in't Veld), causal agent of Sudden Oak Death (SOD) of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), is established in coastal forests of the western United States. Since the discovery of SOD in the Douglas-fir / tanoak forests of...
Humboldt Redwoods State Park in southern Humboldt County, California is a coastal redwood forest, a highly unique and valued ecosystem. It has many social, cultural, ecological, and economic values, including recreational benefits, heritage and aesthetic values, high biodiversity, nutrient cycling, and climate regulation. However, Humboldt County is at risk of...
Colonization of N. densiflorus tissues by P. ramorum is not well understood. The pathogen is able to colonize nearly all tissues of this host but it is unclear how a tree is ultimately killed. Because this is such a destructive invasive pathogen, it is important to investigate its pathogenic strategy....
Tanoak (Lithocarpus densiflorus), along with some other members of Fagaceae, are susceptible to sudden oak death caused by the oomycete Phytophthora ramorum. Symptoms of the disease include dying crowns, bleeding cankers, and eventually death of infected trees. The cause of mortality is not well understood, but recent research indicates that...