Crown gall infection is spread by movement of infested soil, by infected plant material, and via budding and grafting tools.

How do you prevent crown gall spread?

Limit wounding of plant material. Avoid planting too deep. Avoid mounding soil up on newly planted trees. Keep crown of tree as dry as possible; Agrobacterium is favored by wet environments.

How do crown gall infections first appear?

The disease first appears as small overgrowths or galls on the roots, crown, trunk, or canes. Galls usually develop on the crown or trunk of the plant near the soil line or underground on the roots. Above ground or aerial galls may form on canes of brambles and highly susceptible cultivars of grape.