Bondi Junction NSW, Australia
Fact Sheets
Onion black mould (187)
Pacific Pests, Pathogens and Weeds
Pacific Pests, Pathogens and Weeds


  • Worldwide distribution. On seeds, bulbs, tubers, fruits and flowers of coconuts, maize, onion, peanuts, rice, and sorghum, and many other hosts. A cosmetic problem.
  • A fungus, usually on organic matter in soil, attacks stored fruits, seeds, roots/tubers, if they are wounded. On onions, it infects dying leaves in the field after harvest; from there  the bulbs become infected, often along the veins. It also infects onions when “topped” before storage, especially in hot, wet weather.
  • Spread occurs as spores in the wind. The fungus is seed borne.
  • Cultural control: well-drained land; ensure seed is clean, or treat in hot water (60°C for 15 min.); dry bulbs after harvest, before storage; varietal resistance (those with red scale leaves); collect trash and burn after harvest.
  • Chemical control: seed treatment: mancozeb or thiram.

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