Crown gall of grape is an important disease in all areas where grapes are grown worldwide, but is particularly severe in regions with cold climates. Formerly designated as Agrobacterium tumefaciens biovar 3, A. vitis, the bacterium that causes of the disease, only occurs on grape. A. vitis survives systemically in grapevines, and initiates infections at wound sites, such as those caused by freeze injuries. As a result, vineyards in climates with cold winters are prone to suffer extensive damage from crown gall. In addition to freeze-induced wounds, graft unions are also common sites for infection.