Rhynchosporium is a genus of fungi that causes leaf scald disease on several graminaceous hosts. It includes five currently accepted species: R. secalis from rye and triticale, from Dactylis glomerata, from Lolium multiflorum and , from Agropyron, and from Hordeum spp., Lolium multiflorum and Bromus diandrus. R. commune is one of the most destructive pathogens of barley worldwide, causing yield decreases of up to 40% and reduced grain quality.