Covered smut
(Ustilago hordei)

Overview

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Covered smut is a disease caused by the plant pathogen Ustilago hordei, and commonly infects barley and oat crops in Canada. This disease is most characteristically recognized for its semi-persistent membrane that covers the smutted-spiklets. Covered smut is carried over from spores on the seed surface. Infection occurs when seedlings emerge from the sprouting seed and is favoured by conditions of cool soil. The fungus enters the young seedling and grows systemically.

Main description

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Key defining feature of the disease covered smut is the replacement of the head with dark brown spores. Floral bracts and awns partially develop and spores are contained in a membrane until plant maturity, when they are dislodged by threshing and infect the resulting new seed.

Scouting

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When scouting, search near heading for stunted crops. Look for abnormal head emergence through the sheath below the boot leaf. After heading, look for unusual tightly-compacted heads and deformed awns.