Sudden Oak Death (Ramorum Blight)

Sudden Oak Death (Ramorum Blight)
Phytophthora ramorum
Phytophthora ramorum, a fungus-like pathogen, can infect the leaves of many different plants, but rarely kills them.
On oak trees, however, it often infects branches and trunks with deadly results.

Species of blueberry showing leaf discoloration (brown) caused by ramorum blight. Blueberry will carry ramorum blight but it won’t kill the shrub!

Leaves of tanoak (Notholithocarpus densiflorus). Ramorum blight usually kills tanoaks, and many other oaks.

Leaves of a Douglas fir showing wilting and brown needles caused by ramorum blight. Douglas firs are one of many types of plants that can carry ramorum blight without being killed.



Camelias are one of many types of plants that can carry ramorum blight without being killed. These are leaves of a camelia damaged by ramorum blight.

Species of azalea showing brown leaf spots caused by ramorum blight. Azaleas carry ramorum blight without being killed.

Leaves from a California laurel showing leaf discoloration caused by ramorum blight.



Hillsides showing significant loss of tanoaks from ramorum blight.


Gray tree tops of oaks affected by ramorum blight.


Plants in this nursery are being inspected for ramorum blight to make sure that customers who buy them don’t accidentally spread the disease to their own yard!


A nursery being treated for ramorum blight. All pots and containers with infected plants had to be washed, disinfected, and bagged before being buried in a landfill.


Technician disinfecting the inside of a truck used to move plants infected with ramorum blight.


Plants in this area were infected with ramorum blight and had to be burned and buried to destroy the disease.


Are you still curious about
sudden oak death?
Click the button below to find more information and connect with the experts.
California laurel leaf: Joseph O'Brien, USDA Forest Service, Bugwood.org; infected Rhododendron leaves: Joseph O'Brien, USDA Forest Service, Bugwood.org; Twig dieback, wood staining, sap bleeding, discoloration, and cracks: Joseph O'Brien, USDA Forest Service, Bugwood.org; Cankers and bark discoloration: Bruce Moltzan, USDA Forest Service, Bugwood.org; Hypoxylon thouarsianum / sapwood decay fungus: Joseph O'Brien, USDA Forest Service, Bugwood.org; Blueberry, tanoak, Douglas fir, gray tree tops: Joseph O'Brien, USDA Forest Service, Bugwood.org; Camellia leaves: Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org; Gray tree tops: Bruce Moltzan, Bugwood.org; Nursery: Joseph O'Brien, Bugwood.org; Contaminated material in bags, truck disinfection, burning of plants: Chris Evans, University of Illinois, Bugwood.org;