The powdery mildews are a group of fungi that coat leaves, young shoots, flowers and fruits with a conspicuous white or pale grey, ash-like film.

It occurs on many plants including vegetables and ornamentals.

Powdery mildew is more prevalent in warm, humid weather and spreads rapidly from plant to plant by wind.

Control:
Grow mildew-resistant varieties where possible.

Remove and destroy affected foliage. Avoid overcrowding and overhead watering. At first sign of infection, spray with an approved chemical at regular intervals.