Sclerotinia squamosa

Onion showing symptoms of leaf and neck rot. Image: Lindsey du Toit, Washington State University,

  • Also called onion leaf blight.
  • Leaf rot and neck rot affect onions, Japanese bunching onions, Welsh onions, leeks and garlic.
  • Damages leaves, seeds.
  • The first symptoms appear as small white wounds on the leaf surrounded by a greenish halo. This early symptom can easily be confused with insect or mechanical damage, or herbicide injury. In later stages, however, the wounds expand and many new wounds appear that cause premature die-back of leaves.
  • Severely affected onion fields develop a withered appearance and small onion bulbs.
  • Spread by infested soil, plant material, wind, and rain.

High priority pest of: Onions

Scientific name: Botrytis squamosa syn. Sclerotinia squamosa
EPPRD Category:
Life Form: Fungus

Pest Documents

FS: fact sheet

CP: contingency plan

DP: diagnostic protocol