University of Maryland Extension

White Rot of Alliums

white rot

Back to Common Problems - Vegetables 

The first symptoms of stunting, yellowing, and dieback of foliage of onions (see above photo), garlic, and other family members can be a symptom of a  very destructive fungal disease called white rot.  When bulbs are pulled out of the soil they are either coated with a white to gray colored fuzz or with a crusty covering that is embedded with thousands of tiny black sclerotia (reproductive structures). The sclerotia can live in the soil for years without benefit of host plants.

white rot garlic

white rot garlic tops

White rot symptoms on garlic bulbs

White rot symptoms on garlic tops

Management:

  1. Always buy certified disease-free vegetative planting stock (garlic, onion sets, etc.) and seedlings.
  2. Never plant garlic purchased from a grocery store. It may be a symptomless carrier of the disease.
  3. Remove and dispose of infected plants. Do not attempt to compost these plants.
  4. Work in a lot of compost to infected beds and don't plant allium family members for 4-5 years.
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