Smut of oats

Description:
Dark brown to blackish mass of powdery spores replaces the Oat grain. The spore mass is covered by a thin, white or grey membrane which usually breaks soon after the head emerges releasing spores to infect flowering Oats. By harvest only the bare stem of the Oat head with some husks may remain. Infected plants may be stunted and are often difficult to see by harvest.

Infection is favoured by moist conditions during flowering with temperatures from 15-250C.
Early seeding with into warm soils is often associated with outbreaks.

Life Cycle:
Spores released from infected heads are blown to flowering neighbours where they lodge and remain dormant until planting or germinate and grow into the seed coat then remain dormant until planting. After planting the fungus grows within the plant and proceeds to the florets, destroying developing flowers and replacing grain with the spore mass.