Irregular spots or lesions can be seen, with dark reddish brown margins and gray center and discoloration in the sheath.
Serious infection can be found on the leaves, lesions enlarge and often coalesce and may cover the entire leaf sheath. Severe infection causes entire or parts of young panicles to remain within the sheath. Emerging panicles rot and florets turn red-brown, subsequently changing to dark brown. At humid and warm weather conditions, whitish powdery growth from under the may be observed inside the affected sheaths and young panicles. Infected panicles are sterile, or with grains only partially filled.
Cultural control: Choose resistant varieties. Remove infected straws, stubbles, wild rice plants and weeds in time. Choose clear and higher located fields for nursery. Reduce amount of nitrogen and apply it in several lots. Avoid very high humidity in the crop, e.g. by larger plant spacing.
Chemical control: a fungicide according to recommendations provided in the Green & Yellow List may be sprayed when infected areas are identified in the fields.