Maple: Bacterial leaf spot and dieback

Biology

Bacterial leaf spot and dieback is caused by the same bacterium which causes bacterial blight of lilacs and many other woody ornamentals. Symptoms include leaf spots, blackening of leaf veins, and tip dieback. Leaf spots are initially small and appear water-soaked. The spots often have a yellowish halo and can expand in size, killing leaves and young seedlings. One-year-old twigs may die back during the winter, or shoots may die back in the spring. The disease is most common on Japanese, Norway, and red maples.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Avoid wounding plants.
• Try to limit pruning to periods of dry weather to reduce infection risks.
• Remove and destroy dead twigs and infected and fallen leaves.
• Space plants properly and prune to provide good air circulation.
• Maintain proper plant nutrition. Healthy plants resist infection.
• Avoid overhead watering.
• Plant resistant cultivars. Some Japanese maples show no symptoms of bacterial blight.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended.

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