Pathogen is a 'water mold' fungus requiring saturated soil conditions for infection to occur. Diseased plants are most often noticed along or in standing water. Infected seedlings appear stunted, chlorotic, tiller profusely and have thickened, leathery leaves. Severely infected plants usually die before jointing. Infected survivors exhibit twisted heads and leaves. Contrary to the name, 'downy' fungal growth is seldom visible on wheat. Barley, corn, sorghum, oats and 100+ species of perennial and annual grasses serve as alternate hosts.