Crown Rust of Oat in Manitoba and Ontario in 2020

Thirty six fields infested with wild oats and 51 fields of common oats were monitored for incidence and severity of crown rust of oats in 2020 in Manitoba. Crown rust was observed in 92% of fields infested with wild oats, and 86% of common oat fields, with an average of 37% and 15% of plants infected, respectively. Single crown rust isolates from each field were inoculated on to 24 oat lines which differ in single genes for resistance to oat crown rust. None of the resistance genes were found to be effective against all of the crown rust isolates from Manitoba. Four isolates were obtained from Ontario, and 11 of the resistance genes were found to be effective against the Ontario crown rust isolates in 2020.