Petunia Botrytis Blight: Remove Blooms, Improve Airflow, Fungicide

Black fuzzy growth on new petunia blooms is Botrytis blight (gray mold), common in humidity.

Cultural Management

• Remove and discard all faded/blighted flowers and leaves daily.
• Remove debris from soil surface.
• Work during hottest, driest part of day to avoid spreading spores.
• Disinfect pruners between cuts (1:9 bleach:water).
• Avoid overhead watering—water at base only.
• Water mid-morning for rapid foliage drying.
• Thin plants if crowded to improve air circulation.

Fungicides

Apply copper, captan, or chlorothalonil labeled for Botrytis. Spring applications during cool/wet weather are most effective, but treat now if problem persists.

More info: Botrytis Fact Sheet