Powdery mildew

Disease A white powdery coating that appears on leaves and stems in dry, warm weather.

What to look for

White or grey powdery patches on leaves, stems and sometimes fruit. Leaves yellow, curl and drop. Common on courgettes, cucumbers, peas, apples and gooseberries.

When: June to October, worst in hot, dry spells with humid nights.

How to prevent it

• Water regularly at the base, as dry roots make plants more susceptible.
• Space plants for good air circulation and avoid overcrowding.
• Mulch to hold moisture in the soil.
• Choose resistant varieties.

How to deal with it

• Remove affected leaves as soon as you see them and bin them rather than composting.
• Water well in the morning and feed to keep plants vigorous.
• Late-season mildew on courgettes and squash is usually harmless once the crop is nearly done.

Crops it affects

💙 Borage🎃 Butternut squash🌼 Calendula🌼 Chamomile🌿 Chervil🥒 Courgette🥒 Cucumber🌿 French tarragon🥒 Gherkin🟢 Gooseberry🍇 Grape🌻 Jerusalem artichoke🍋 Lemon balm🥒 Marrow🍈 Melon🌿 Mint🎃 Patty pan squash🫛 Pea🎃 Pumpkin🌿 Sage🥔 Swede🌿 Sweet cicely🌸 Viola and pansy

If you choose to use any treatment, use only products approved for UK home gardens, follow the label and avoid spraying open flowers. See all pests and diseases.