Powdery mildew (as pest pressure)

What you see

White talcum-powder patches on the UPPER leaf surface that rub off with a finger.

Damage

White dusty patches spreading across leaves, later yellowing and browning. Reduced yield and flavour.

Lifecycle on this coast

Thrives in warm days with cool humid nights - it does NOT need wet leaves, unlike most fungi. Spreads on air currents.

When to act

Act at the first patch, before it covers a third of the leaf.

Months: June, July, August, September

Plants it bothers

Courgette, Pumpkin, Cucumber, Grape, Rose, Melon, Strawberry, Apple

Natural enemies

Not recorded — the field is blank rather than guessed.

Remedies

Potassium bicarbonate spray, Milk spray, Wettable sulphur, Neem oil spray

The thing people get wrong

It is the one common fungus that does NOT need wet leaves - so overhead watering is not the cause, and keeping the leaves dry will not save you. Spacing, airflow and a bicarbonate spray at the first patch are what work.