Diagnosing Brown Spots on Magnolia Flowers: Botrytis vs. Beetle Damage

Botrytis Blight on Magnolia Blooms

Brown spots on unopened flowers, especially in damp weather, suggest botrytis (gray mold). Spores are airborne.

Cultural Controls: Watering and Sanitation

Water at the base only—never overhead. Remove and destroy (burn) infected flowers. Do not compost.

Japanese Beetle Feeding Signs

Beetles chew leaves and petals. If leaves are also damaged, beetles are likely. Traps help but may attract more.

When to Consult Extension Services

Take a sample to your county extension office (e.g., UVM Extension for Vermont) for definitive diagnosis.