Disease Gallery

Name: Crown Gall

Latin Name: Agrobacterium tumefaciens

Description: A bacterial disease that girdles trees. Introduced through wounds and manifested by winter injury. Large tumor-like growths occur near base of trunk, but can also be seen on other areas.

Disease Life Cycle: Bacteria live in the soil on infected tissues. Enters plant through pruning and grafting wounds, as well as other damage like winter injury, hail damage, insect entry points, and mechanical damage. Galls usually form annually in late spring or early summer, and reduce tree vigor by restricting the flow of water and nutrients. The bacterium can be spread from infected trees to other areas by transfer of the soil on equipment (mowing and tilling).

Disease Symptons: Initially appear as fleshy, cream colored galls and later turn brown and woody. Affected trees are weak and may die. Infected trees can be more susceptible to cold damage. Young trees may be girdled in one season and die.