Fusarium oxysporum f.sp. medicaginis (Fusarium wilt of alfalfa).

Abstract Fusarium oxysporum is a common soil inhabitant around the world. It is regarded as a species complex that includes non-pathogenic, plant pathogenic, and human pathogenic strains. The plant pathogens cause wilt diseases on most crop plants. F. oxysporum f.sp. medicaginis causes a fatal wilt disease on Medicago sativa, M. truncatula, and Vicia sativa. It is found throughout the USA and in Alberta, Canada. The limited reports of Fusarium wilt of alfalfa outside of these areas suggests that the pathogen is native to North America. The pathogen is potentially invasive through movement of infested soil; it is not seedborne. Infected alfalfa plants usually die several months after infection and can lead to significant stand and yield losses. Nearly all modern commercial cultivars are highly resistant or resistant to Fusarium wilt. F. oxysporum f.sp. medicaginis is not on an alert list nor is it a regulated pathogen.