Powdery Mildew: Identification, Control & Prevention

Powdery mildew coats plants in a white, flour-like dust. Unlike most fungi, it doesn't need free moisture—thriving in warmth and humidity. Spores spread on wind, weakening plants, reducing blooms, and potentially killing severe infections.

Identification

• Circular white powdery spots on leaves, stems, fruit.
• Upper leaf surfaces affected first; older leaves yellow and dry.
• Leaf twisting, breaking, distortion.
• Spreads to cover most foliage; buds and growing tips distort.
• Typically appears late in growing season.

Control

• Rub infected leaves together to partially remove spores.
• Remove and destroy all infected parts—do not compost.
• Spray fungicides: sulfur, lime-sulfur, neem oil, potassium bicarbonate.

Prevention

• Choose resistant/tolerant varieties.
• Reduce humidity: avoid overhead watering; prune for airflow.
• Prophylactic sprays: commercial fungicides or 1 tsp baking soda/quart water (spray thoroughly).