True loose smut


Names

True Loose Smutzoom...

Scientific Name

Ustilago nuda

Biology

Description

Masses of spores emerge in place of normal heads. Plants show no symptoms. The entire head, except for the rachis, is replaced with dusty, dark brown spores covered with a thin membrane. Spore masses may be easily mistaken for false loose smut but are not quite as dark. Spores are released by wind and rain and don’t cause reduction in grain quality for feed but do affect quality of grain grown for seed. Disease development requires sufficient humidity and temperatures between 16° and 22° C. As the seed germinates, embedded smut mycelium starts to grow and penetrates plant tissues near growing point. The fungus grows inside young plants without causing symptoms. Infected seed does not differ visually from healthy seed – only laboratory analysis can detect infection.


Scouting

Check crops shortly after head emergence before the thin membrane that surrounds the masses of smut spores breaks and the spores are blown away. Within a couple of days, only the bare rachis remains. At harvest, check for bare heads with only the rachis remaining.


Control

Resistant cultivars have been developed. Use smut-free seed.

Occurence

Crops

  • Barley

Control

Chemical Control

Products that control

  • Raxil

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