Crown gall is caused by a soilborne bacterium. The bacteria infect through wounds on the crown and roots. Young galls are fleshy, white, enlarged masses on the roots or stems. Older galls are hardened and turn dark brown and woody or corky in appearance. They range in size from less than an inch to several inches across. The bacteria may be transmitted on infected nursery stock. Water movement can spread the bacteria from infected to clean soil. Damage varies with location and size of galls. Small galls are essentially harmless. Large galls on the crown may weaken or girdle trees. The growths can also be an aesthetic concern.

Management Options

Non-Chemical Management

Plant disease-free materials.
Remove and destroy declining trees with large crown galls. Also remove roots and surrounding soil where possible.
Prune out galls when practical. Sterilize pruning tools between cuts to avoid spreading bacteria to healthy tissue.
Avoid injuries to the bark, roots, and crown when planting.
Do not replant susceptible species in infected soil.

Select non-chemical management options as your first choice!

Chemical Management

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

None recommended

Images

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Caption: Crown gall Photo by: R.S. Byther

WSU Extension

Hortsense