Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Onion smudge (186)

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  • Worldwide distribution. On onion, leek, Welsh onion (Japanese bunching onion), Chinese chive, shallot. A cosmetic disease.
  • On the lower parts of the outer leaves and neck, in patches or rings.
  • Spore masses with long stiff hairs. Spots on leaves turn to blights under wet warm conditions.
  • More serious rots occur if onions harvested wet and stored moist >20°C.
  • Causes a seedling damping-off.
  • Spread occurs in wind-driven rain.
  • Cultural control: well-drained soil; clean seed and healthy transplants; avoid harvesting in wet weather; cure bulbs quickly and store cool and dry; plant those with coloured outer scales; 2-3-year crop rotations.
  • Chemical control: possibly, mancozeb, or chlorthalonil.
Common Name

Smudge of onion bulbs, anthracnose of onions

Scientific Name

Colletotrichum circinans

AUTHOR Grahame Jackson
Information from Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, et al. CSIRO Publishing; and CABI (2021) Onion Smudge (Colletotrichum circinans) Plantwise Knowledge Bank. (; and from Rollins J (2014) Colletotrichum circinans. BugwoodWiki. ( Photo 1 Gerald Holmes, California Polytechnic State University at San Luis Obispo, Photo 2 Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, et al. CSIRO Publishing. Photo 3 Cesar Calderon, USDA APHIS PPQ,

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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