Onion smut
Onion Smut
Onions infected with smut
Scientific Classification
Kingdom: Fungi
Phylum: Basidiomycota
Subphylum: Ustilaginomycotina
Class: Ustilaginomycetes
Subclass: Ustilaginomycetidae
Order: Urocystales
Family: Urocystaceae
Genus: Urocystis
Species: Urocystis magica

Uburcinia cepulae Liro (1922)
Urocystis cepulae Frost (1877)
Urocystis colchici var. cepulae Cooke (1877)

Urocystis magica Pass. (1875)

Onion smut (Urocystis magica) is a tough disease of the onion because it can last for years in the soil as spores. When the onion crop is planted the spores germinate and enter the fresh seeds.[1]


When the plant grows lesions form on the leaf and any bulbs that form will be covered in black spots. Most of the time infected seeds will die within 3–5 weeks of planting.[1]


None. Lift and burn diseased plants.[2]


Leeks and onions should not be grown in the same site for 8 years.[2]


  1. a b ["Crop Profile for Onions in New York". USDA. May 1999.
  2. a b Hessayon, D.G. (2009). The Vegetable & Herb Expert. Transworld Publishers, London. p. 75. ISBN 9780903505468

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