WSU Extension

Hortsense

Onions, Garlic
 
Disease
Basal rot 
Downy mildew 
Gray mold 
Neck rot 
White rot 
Insect
Onion maggot 
Onion thrips 



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Caption: Sclerotia on surface of white rot-infected bulbs
Photo by: R.S. Byther
  
Onions, Garlic : White rot
(revision date: 6/3/2014)


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


Non-Chemical Management
  • 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.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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