What Is Wrong With My Plum Trees?

Identification

• Plum trees are susceptible to cytospora canker, a fungal disease caused by Cytospora spp. The fungus commonly enters the trees during dormancy periods through broken bark, tree wounds or pest damaged sites on the tree.

Damage

• The disease is characterized by the appearance of brown, irregular, sunken patches on the bark of the tree, on branches and on twigs. There is a secretion of sticky gum from the edges of the cankers. In severe infections, cankers encircle or girdle branches and kill them entirely. Foliage of infected trees shrivels and dies.

Management

• Prune and remove all affected tree areas during summer, cutting a few inches below the canker. Avoid excessive fertilizer use and overhead irrigation. Do not plant in shallow ground. Whitewash trees to seal wounds. This also protects trees from sunburn damage.