Black Leaf Spots on Corkscrew Willow: Late-Season Fungal Spots and Prevention

Diagnosis

The black spots are fungal leaf spots appearing late in the season as the tree prepares for dormancy. They rarely threaten overall health.

Management

This Year

• Rake and remove all fallen leaves to reduce spore carryover.
• No need to spray now—fungicides are preventive, not curative.

Next Spring (Preventive Program)

1. Begin spraying as leaves unfurl.
2. Apply copper fungicide (e.g., Hi-Yield Copper Fungicide) or mancozeb (Bonide Mancozeb Flowable) every 2 weeks for 3 applications.
3. Spray to full coverage until leaves are fully expanded.

Long-Term Care

Maintain tree vigor with proper watering and spring fertilization. Healthy trees resist leaf spot severity naturally.