Crown Gall
Agrobacterium tumefaciens (Rhizobium radiobacter)
Overview
A bacterial disease causing tumor-like galls on roots, crowns, and stems of many woody and herbaceous plants. The bacterium transfers DNA into plant cells, reprogramming them to produce gall tissue.
Symptoms
Rough, irregular, tumor-like galls on roots, crown, and lower stems. Galls start soft and light-colored, becoming hard, dark, and woody with age. Girdling of stems reduces vigor. Stunted growth and decline.
Environmental Conditions
Variable
Prevention
Inspect nursery stock carefully before planting. Avoid wounding roots and stems during planting and cultivation. Dip bare-root plants in Agrobacterium radiobacter K84 (biological control) before planting.
Management
No chemical cure. Remove and destroy severely infected plants. Prune galls from valuable plants and treat wounds. Biological control with A. radiobacter K84 is preventive only. Solarize infested soil.