Onions, Garlic: White rot

categories: Onions, Garlic Onions, Garlic Diseases Vegetables

revision date: 2022-12-07 12:00

Sclerotia on surface of white rot-infected bulbs.
Sclerotia on surface of white rot-infected bulbs
Photo by: R.S. Byther

Biology

White rot is a fungal disease which affects onions and related species. Cool, wet conditions may be followed by wilting and yellowing of leaves beginning at the base of the plant. Affected plants eventually die. Roots are destroyed and a white, fluffy mass of fungus may cover the bulbs. Small, black fungal structures may be present in the white fungal growth. These structures (sclerotia) are smaller and rounder than those of Botrytis neck rot. They are often found near the base of the bulb. Infected bulbs will continue to decay in storage, turning soft and watery. The fungus can persist in the soil for long periods. This disease is a serious problem of onions and related crops.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Rotate crops. Do not plant onions or related species into infested soils more often than every 8-10 years.
  • Plant disease-free sets.
  • Plant in well-drained soils.
  • Do not move infested soil into non-infested areas.
  • Remove all infected plants and the adjacent healthy plants. Remove soil around infected plants when practical. Destroy or discard (do not compost) diseased materials.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • None recommended.

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