What Is Wrong With My Maple Tree?

Identification

• Maple trees are susceptible to bacterial leaf blight or bacterial leaf spot caused by Pseudomonas syringae. The bacteria thrive during extended wet weather. Damage is more pronounced in wet and humid areas.

Damage

• The disease is characterized by the appearance of small to large, irregular brown spots on foliage. As disease progresses, the spots spread to the flowers, stems and fruit. Cankers appear on branches and streaks on wood. Severely infected tissues also start to secrete gum.

Management

• Prune and remove all infected tree areas. Plant trees in well-ventilated areas to minimize humidity levels. Avoid overhead irrigation as this creates prolonged moisture on foliage. The appearance of cankers on a tree indicates a chronic stage of disease. Remove chronically infected trees entirely.