Utah State University Extension
Sudden oak death (SOD) and ramorum blight are caused by Phytophthora ramorum, a non-native water mold (oomycete) that originates from parts of Asia. Sudden oak death was given its name due to the appearance that entire trees were dying in just 2 to 4 weeks. In reality, the disease progresses over an extended period, estimated at more than 2 years after initial infection. Ramorum blight is nonlethal, typically causing foliar browning and wilting. This fact sheet discusses impact, damage and symptoms, plant hosts, disease cycle, and management.
Murray, M. & Mull, A. (2023). Sudden oak death and ramorum blight [Fact sheet]. Utah State University Extension.