Sheath Rot

Symptom

Sheath rot appears on the uppermost leaf sheaths enclosing the young panicles. The lesions start as oblong or somewhat irregular spots with brown margins and grey centres, or they may be greyish-brown throughout. They enlarge and often coalesce and may cover most of the leaf sheath. The young panicles remain within the sheath, do not develop further and rot, only partial panicle emergence may be observed. Young lesions show whitish, powdery growth both outside and inside affected sheaths. Old lesions have less or no powdery growth of the fungus and appear as dry, brownish lesions with the enclosed panicle rotted. Most grains are sterile, shriveled, partially or unfilled, and discolored.