A NEW RACE OF FUSARIUM OXYSPORUM f. PISI

Abstract

Pea varieties resistant to Fusarium wilt and near-wilt developed a wilt disease when grown in a field disease nursery at Ottawa. Two isolates of Fusarium oxysporum f. pisi (Linford) were obtained from infected plants. When tested, one of these was similar to F. oxysporum f. pisi race 2 (near-wilt) in host range and cultural characteristics. The other resembled F. oxysporum f. pisi race 1 (wilt) in morphology and cultural characteristics, but caused severe symptoms on New Era and Wisconsin 183, varieties resistant to races 1 and 2. It was concluded that this latter isolate is a new race; it is proposed that it be designated as F. oxysporum f. pisi race 4.