Handbook Bulletin 861 Chapter 4 Grapes Crown Gall Crown gall is a bacterial disease caused by Agrobacterium tumefaciens that infects more than 2,000 species of plants. Crown gall of grape is a major problem in cold climate regions. Wounds are necessary for infection to occur. Observations suggest that freeze injury wounds are highly conducive to infection. The disease is particularly severe following winters that result in freeze injury on cold-sensitive cultivars, such as those of Vitis vinifera .
Crown gall is characterized by galls or overgrowths that usually form at the base of the trunk.
Galls generally do not form on roots. The disease affects all grape cultivars. Vines with galls at their crowns or on their major roots grow poorly and have reduced yields. Severe economic losses result in vineyards where a high percentage of vines become galled within a few years of planting. The disease first appears as small overgrowth or galls on the trunk, particularly near the soil line.