Identification

• Maple trees are susceptible to bacterial blight caused by Pseudomonas syringae. The disease symptoms are more pronounced in areas with wet weather. The bacterial growth is also supported by extended spring rains.
  
  

Symptoms

• Bacterial blight is initially characterized by the appearance of very small, water-soaked spots on the foliage ranging in size from pinpoint to 1/4-inch circles. This is accompanied by the blackening of veins and tip dieback. The spots have a yellow border in early stages of growth. As the disease progresses, the spots grow larger and merge, causing foliage to wilt and die.
  
  

Management

• Prune and remove all affected plant areas. Plant trees in areas with good ventilation and use resistant varieties. Remove trees entirely if cankers appear on the trunk. Trees with only the foliage affected are likely to recover. There are no bactericides for control of the disease.