Spot Blotch (fungus - Bipolaris sorokiniana): Spot blotch infection starts as dark brown-to-black spots on sheaths that cover the young shoots. The infection progresses inward and sometimes kills the seedlings below the surface of the ground, but more often it kills the seedlings after emergence. Diseased seedlings are dwarfed and tiller excessively. The leaf spot has round to oblong dark brown lesions. Spots may coalesce to form blotches. As crown rot, the disease develops at or near the soil line. Crown roots may be rotted and tillers killed. The pathogen can be soil- or seed-borne, and may be carried on crop residue. Seed treatment with a fungicide (Table 2) reduces losses from seedling infection. Clean plowing of crop residue and crop rotation will aid in control.
