Sheath Spot

Aggregate sheath spot lesions first appear on the lower leaf sheaths at the water line during the tillering stage. Lesions are circular to elliptical with gray-green to straw-colored centers surrounded by distinct brown margins. Frequently, additional margins form around the initial lesion, producing a series of concentric bands. A strip of light-colored necrotic cells runs down the lesion center. Later in the season, secondary infections frequently occur well above the water line.