Onions, Garlic: Basal rot

Biology

Basal rots of onion, garlic, and related species are caused by fungi. Affected plants are yellowed, wilted, and grow poorly. Reddish discoloration may be present on affected garlic, while onions may show a red-brown rot beginning where roots are attached to the bulb at the basal plate. Initial infection typically occurs on the roots or the basal plate. The rot progresses upward through the bulb and can also occur in stored infected bulbs when sufficient moisture is present. Plants attacked by onion maggots or other insects are more likely to be infected.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

• Plant tolerant onion cultivars such as ‘Bronze Reserve’, ‘Cashe’, ‘Cima’, ‘Golden Cascade’, ‘North Star’, ‘Oro Grande’, ‘Sassy Brassy’, ‘Sentinel’, and ‘Valient’.
• Control insects and prevent root damage such as that caused by overfertilization.
• Rotate crops. Do not plant onions or related crops in the same locations each year.
• Plant in well-drained soils.
• Dry bulbs before storing. Store bulbs in cool, dry, well-ventilated locations.

Chemical Management

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

• None recommended.

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