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Red Maple Dual Issue: Phyllosticta Leaf Spot and Harmless Lichens

North Carolina red maples with branch dieback, dark rough coating (lichens), and leaf spots—two separate issues: fungal leaf spot (Phyllosticta) and benign lichens on declining branches.

Issue 1: Phyllosticta Leaf Spot

Circular tan spots with purple-red borders
Black fruiting bodies in rings late season
Affects Amur, Japanese, red, silver maples
Late-season = minimal damage, early leaf drop only
Control: mancozeb or chlorothalonil in SPRING (preventive)
Large trees: rarely worth spraying

Issue 2: Lichens on Branches

Symbiotic algae+fungi — NOT parasitic
Crustose (flat), foliose (leafy), fruticose (shrubby) forms
Indicate THIN CANOPY (more light), not cause of decline
Control: improve tree vigor → denser shade → lichens decline

Japanese Maple Green Growth

Green growth on Japanese maples = likely algae/moss, same principle. Improve vigor.

Integrated Approach

Soil test → targeted fertilization
Mulch, water, protect trunks
Spring preventive fungicide IF high-value specimens
Accept late-season leaf spots as cosmetic

Lichens are nature's canopy density meter. Thicken the canopy; lichens fade.

Plant Diseases: Maple Anthracnose: Brown Veinal Discoloration—Cultural and Chemical Control; Red Maple Bark Splitting: Frost Cracks, Lichens, and Decline Risk; Phyllosticta Leaf Spot on Japanese Maple: Cosmetic Late-Season Fungus; Red Leaf Maple Dieback: Winter Desiccation and Canopy Restructuring; Japanese Maple Branch Dieback and Green Insects: Systemic Atomic Grow Rescue; Bark Peeling on Mature Japanese Maple: Sunscald or Something Else?; Red Maple Leaf Galls: Harmless Insect-Induced Growths; Japanese Maple Leaf Spots: Phyllosticta (Purple Eye); Red Maple Leaf Scorch in Extreme Heat: Recovery Watering; Red Maple Leaf Spots vs. Galls: Identify Before Treating

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