Sudden Oak Death (Phytophthora ramorum)

The causal agent of Sudden Oak Death (SOD) disease, the Oomycete pathogen Phytophthora ramorum, is distinct from the other well studied model Phytophthora species, P. infestans (the potato blight pathogen) and P. sojae (soybean pathogen), in that it infects several host species from different genera. The current USDA list of susceptible hosts includes 117 different species. In California P. ramorum is killing the keystone species live oak as well as several other woody species that inhabit the oak ecosystems. P. ramorum causes over $60M per year in damage and Canada is spending about $1M per year to prevent its introduction (close to 200,000 samples processed since 2002). This pathogen has not become established in Canada yet and is a major concern in Ontario and across Canada because of the realisation that the list of species that it can infect continues to grow.