The Crown Gall disease is so cosmopolitan in its host - range that the cherry could not be expected to escape in all cases. It is the younger trees that suffer, particularly if the knots, or galls, surround the crowns. In the North, at least, it has been observed that little injury is done to mature trees. Sometimes trees planted with galls may outgrow the disease in a year or so. It is not safe, however, to assume that this will always occur; affected trees should not be used in plantings. (See fuller discussion under Apple, page 108.)
Among the stone fruit-trees affected by this root disease the cherry stands out as one of the most resistant. In the Pacific Northwest, however, a few cases of Root Rot caused by Armillaria mellea have come to the attention of growers and plant pathologists. Special discussion is not necessary here; see Apple, page 96.