Twig Blight Disease

Identification

• Twig blight disease affects most species of plants, trees and shrubs and is caused by a multitude of fungal pathogens that are specific to the specimen in question. It belongs to the anthracnose group of diseases that produce dark sunken lesions on twigs, stems, flowers and fruit. The fungi do not multiply in dry weather and demand warm, wet conditions in order to spread throughout a tree or plant and to adjacent specimens.

Effects

• Twig blight disease is characterized by the formation of cankers -- open wounds -- that appear on the twig, trunk and branches as dark, depressed areas surrounded by a circle of callused tissue. The area typically oozes a diseased resin of varying colors, depending on the species of fungi and the plant. The canker may girdle -- strangle -- the affected area, denying it water and nutrition and thus contributing to the death of the tissue.

Symptoms

• The fungi of the disease overwinters on the plant or amid litter that has fallen to the ground, coming to life in the spring with the occurrence of warm, wet weather. Before cankers appear on the twigs, the first symptoms of twig blight normally display on the foliage as tan or dark brown spots appear on the leaves. In advanced stages of the disease, leaves will fall prematurely from the plant and the entire specimen may defoliate.

Management

• Twig blight disease is primarily an aesthetic problem if it occurs only on scattered occasions. But, if the problem is rampant every growing season, the plant may die as it is continually weakened. The removal and destruction of infested litter each fall is paramount in controlling the disease, while infected twigs should also be pruned and burned. Providing adequate spacing for plants in order to improve air circulation and keep the specimen dry is of extreme help in managing twig blight disease.