Ramorum Blight or Sudden Oak Death

Nate's interest in fungi and their close relatives such as Ramorum Blight (also known as Sudden Oak Death) will be beneficial to tree ecology; he cares about the plants and trees and is always learning to help stop the spread of this pathogen.  Check out the field guide below and then scroll to the bottom of the page to learn how you can help!

Printable Field Guide: PDF

  • Species of blueberry showing leaf discoloration (brown) caused by ramorum blight. Blueberry is one of many plant types that can carry ramorum blight without being killed!  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Leaves of tanoak, Lithocarpus densiflorus. Ramorum blight is usually fatal to tanoak.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Species of azalea showing leaf discoloration (brown) caused by ramorum blight. Azaleas are one of many plant types that can carry ramorum blight without being killed.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Leaves from California laurel showing leaf discoloration caused by ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Leaves of a redwood tree showing leaf discoloration (brown) caused by ramorum blight. Redwoods are one of many plant types that can carry ramorum blight without being killed.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Leaves of a camelia showing leaf discoloration (brown) caused by ramorum blight. Camelias are one of many plant types that can carry ramorum blight without being killed.  Photo Credit: Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org

  • Tip dieback on tanoak, Lithocarpus densiflorus, one of the more susceptible species to ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Wood staining caused by ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Bleeding ooze from a tree infected with ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Fruiting bodies of a sapwood decay fungus, Hypoxylon thouarsianum, that are frequently found on trees in advanced stages of ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Trunk showing cracks and bleeding discoloration caused by a ramorum blight infection.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Bark discoloration and cankers on a coast live oak, Quercus agrifolia, infected by ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Hillside showing significant loss of tanoaks from ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Hillside showing significant loss of tanoaks from ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Hillside showing significant loss of tanoaks from ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • Gray tree tops of oaks killed by ramorum blight.  Photo Credit: Bruce Moltzan, Missouri Department of Conservation, Bugwood.org

  • Inspecting a plant nursery for ramorum blight.  Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • A growing area being treated for ramorum blight. All plant material had to be burned and buried.  Photo Credit: Chris Evans, River to River CWMA, Bugwood.org

  • A technician disinfecting the inside of a truck that was used to move plants infected with ramorum blight.  Photo Credit: Chris Evans, River to River CWMA, Bugwood.org

  • A nusery being treated for ramorum blight. All pots and contaniers had to be washed, disinfected, and bagged before being buried in a landfill.  Photo Credit: Chris Evans, River to River CWMA, Bugwood.org

Scientific Name: Phytophthora ramorum

Description: The disease is a fungus-like microoorganism, so it is small, but it can be spotted by observing trees for signs of reddish cankers and black mold.

Range: Western United States and Europe

 

Map courtesy of USDA's Hungry Pests  - Pest Tracker

Host Trees: Coast live oak and tanoaks are the most frequently killed by Ramorum blight. However, there are a number of alternate hosts such as camellia and rhododendron that can have (and spread) the disease but only show minor symptoms.