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White Spots on Red Maple: Superficial Fungus/Algae, Not Harmful

Mature Maple Has White Patches on Lower Branches in Winter

Chicago area. White, paint-like spots 1–5 inches on lower branches only. No texture like lichen. Pure white.

Expert Identification

Superficial fungus or algae (cosmopolitan) on dead outer bark. Not a concern. Water appropriately in summer. Avoid trunk/root wounds—they let in decay organisms.

Personal Note

Steve plans first Chicago trip next month, looking forward to aquarium.

Plant Diseases: Multiple Tree Decline: Red Maple, Rhododendron, Magnolia, Japanese Maples; Maple Leaf Underside White Spots: Galls or Aphids; White Spots on Maple Leaves: Cottony Cushion Scale; White Powdery Spots on Maple Leaf Undersides: Likely Insects; Phyllosticta Leaf Spot on Japanese Maple: Cosmetic Late-Season Fungus; Maple Trunk White Spots: Harmless Lichens; Red Maple Borer Infestation: Sap Flow and Bud Failure; Red Balls on Maple Leaves: Eriophyid Mite Galls, Not Disease; White Spots on 'King Crimson' Maple: Common Leaf Fungus, Easy Management; Minor Leaf Spots on Young Japanese Maple

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