- The symptoms of the disease are found on leaves, glumes , coleoptile, leaf sheaths, and panicle branches and rarely on roots of young seedlings and stems.
- Typical spots are small, oval or circular in shape and are dark brown or purplish in colour.
- Fully developed lesions are oval, brown with gray or whitish centre of about 1 cm long.
- Numerous such spots occurring on leaves cause withering. Glumes also show similar dark brown spots.In such grains, the endosperm turn black in colour.
- The infected seed on germination show black spots on the coleoptile and cause death of the seedlings (seedling blight).
Select 100 leaves at random from the field. Group the leaves according to the severity of infection based on visual observation. Work out the percentage of leaf area damaged. Rate the damage as < 10 % mild; 10-25 % moderate and >25 % severe.