Maple Leaf Spots: Phyllosticta and Tar Spot

Your golden maple's spreading brown spots with premature leaf drop suggest one of two common fungal leaf spots:

1. Phyllosticta Leaf Spot (Purple Eye)

• Caused by Phyllosticta minima.
• Spots: pale yellow centers with purple-brown borders, ~1/4 inch.
• Black fruiting bodies in rings within spots.
• Can cause partial defoliation.

2. Tar Spot

• Caused by Rhytisma acerinum.
• Starts as light green/yellow spots in early summer.
• Develops raised, shiny black "tar" dots by late summer.
• Mostly cosmetic—rarely threatens tree health.

Management for Both

1. Rake and destroy all fallen leaves (primary overwintering site).
2. Fungicide protection (if warranted):
   • Copper fungicide (Hi-Yield, Ferti-lome)
   • Mancozeb (Bonide, Southern Ag, Dragon)
   • Apply 3 times at 2-week intervals starting at bud break.
3. Improve air flow via pruning.
4. Resistant red maples: 'Autumn Flame', 'Tilford', 'Gerling'.

Key Point

Fungicides are preventive only—apply before symptoms appear. Once spots are visible in summer, treatment protects only new growth. Focus on sanitation and spring protection next year.