This disease is not common in Canada, but it does occur on oats in north-central and western Alberta. It infects all parts of the plant. Spores of this fungus overwinter on the seed and crop residue. Initial infections usually result from soil-borne inoculum. Upper plant parts are usually infected later in the season from spores spread by splashing rain or wind.
Spore production is favoured by poor soils, high pH and wet weather.
Crops that are nutritionally stressed are especially susceptible. Damage Description Brown lens-shaped spots appear on the leaves of oats. Crown and lower stem areas become bleached and then turn brown. Small black dots, which are sexual fruiting bodies, are produced on dead tissue. Crown infections reduce plant vigor and cause premature ripening.