Japanese Maple Decline: Canker Diseases and Water Management

13-year-old Japanese red maple in Maine has dead top/middle branches, trunk deformation, peeling bark, and new branch dieback. Expert lists four fungal diseases: Anthracnose (reddish-purple leaf spots, wet conditions), Botrytis (gray mold on dead tissue), Fusarium (stem lesions), Verticillium (brown/black streaks in cambium, fatal, no chemical control). Prune with sterilized tools, burn debris. Improve air flow, avoid wet foliage. Atomic Grow recommended. Check watering—remove mulch to dry soil if too wet.

Key Actions

• Identify which fungus via leaf symptoms.
• Prune dead wood with sterilized tools.
• Improve drainage and air circulation.
• Consider Atomic Grow for systemic health.

Verticillium is the most serious; manage others culturally.