Aphids (greenfly and blackfly)

Pest Small sap-sucking insects that cluster on soft shoot tips and leaf undersides.

What to look for

Clusters of tiny green, black or grey insects on shoot tips, flower buds and the undersides of leaves. Leaves curl, growth is stunted, and the plant may be sticky with honeydew, which turns black with sooty mould. Ants running up a plant often mean aphids.

When: April to September, peaking in warm, dry spells.

How to prevent it

• Encourage ladybirds, lacewings and hoverflies with open flowers such as calendula and borage, and leave some wild corners.
• Avoid heavy nitrogen feeding, which produces the soft growth aphids love.
• Check plants weekly from April, as early colonies are easy to deal with.
• Grow a sacrificial plant such as nasturtium to draw blackfly away from beans.

How to deal with it

• Squash small colonies with your fingers or wipe them off with a damp cloth.
• Blast plants with a jet of water, which knocks aphids off and they rarely return.
• Pinch out the infested tips of broad beans and cut off badly hit shoots.
• Spray with a soft soap or fatty-acid solution in the evening, away from open flowers, to protect bees.

Crops it affects

🌿 Angelica🍎 Apple🍆 Aubergine🌿 Basil🫐 Blackcurrant💙 Borage🫘 Borlotti bean🫘 Broad bean🌿 Bronze fennel🥬 Brussels sprouts🎃 Butternut squash🌼 Calendula🥕 Carrot🥦 Cauliflower🌼 Chamomile🍒 Cherry🌿 Chervil🥬 Chicory🌶️ Chilli pepper🌱 Chives🌿 Coriander🥒 Cucumber🌿 Dill🫛 Edamame🫐 Elder🥬 Endive🌿 Florence fennel🫛 French bean🥒 Gherkin🌿 Globe artichoke🟢 Gooseberry💙 Hyssop🥬 Kale🥬 Komatsuna🥗 Lamb’s lettuce🌾 Lemongrass🥬 Lettuce🌿 Lovage🍈 Melon🌿 Mint🥗 Mizuna🌼 Nasturtium🍃 Orache🌿 Oregano🌿 Parsley🍑 Peach🟠 Physalis (Cape gooseberry)🟣 Plum🟣 Radicchio🍒 Redcurrant🥗 Rocket🥦 Romanesco🫘 Runner bean🥕 Salsify🌿 Savory🥕 Scorzonera🥦 Sprouting broccoli🍓 Strawberry🌿 Sweet marjoram🫑 Sweet pepper🥬 Tatsoi🌿 Thyme🟢 Tomatillo🍅 Tomato🟣 Turnip🌸 Viola and pansy🌿 Watercress⚪ Whitecurrant🍃 Winter purslane

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.