The grains may be infected by various organisms before or after harvesting causing discolouration.

The disease development is more under high humid conditions leading to discolouration of 30 to 40 per cent grains. Dark brown or black spots appear on the grains.

Around 6-8 kinds of fungal pathogens causes the disease.

This disease is responsible for quantitative and qualitative losses of grains.

Indiscriminate use of nitrogen leads to more grain discoloration.