Treating Powdery Mildew on Crimson King Maple

Identifying and Controlling a Common Fungal Disease

A 4-foot seedling-grown Crimson King Maple shows gray-white powdery coating on leaves—classic powdery mildew. This superficial fungus thrives in cool, damp conditions and can cause leaf curling, yellowing, and premature drop.

Fungicide Treatment Protocol

Begin spraying at first detection. Use a spreader-sticker and cover both leaf surfaces. Repeat on a schedule, more frequently in cool, wet weather. Effective fungicides include:

• Triadimefon (Bayleton, Strike)
• Triforine (Funginex)
• Thiophanate-methyl (Cleary's 3336, Domain)
• Propiconazole (Banner)

While rarely fatal, severe infections weaken the tree and reduce ornamental value.