Aphids (Greenfly and Blackfly)
Pest · Commonly affects: Roses, Broad beans, Runner beans, Kale, Sweet peas, Apple trees, Courgettes
Aphids, commonly called greenfly and blackfly, are sap-feeding insects found on ornamentals, fruit and vegetables throughout the UK. They multiply quickly in spring and summer, particularly on soft new growth. Small colonies can become extensive, weakening plants and spreading sticky honeydew across leaves, stems and nearby surfaces.
How to identify it
Look for clusters of soft-bodied, pear-shaped insects, usually 1 to 4 mm long, on shoot tips, flower buds and the undersides of leaves. They may be green, black, grey, yellow or pink, and some adults have wings. Curled or puckered young leaves, shiny honeydew and black sooty mould are useful clues. Ants travelling repeatedly over a plant often indicate aphids, as they collect the honeydew.
Damage
Aphids drain sap from tender growth, causing leaves to curl, distort or turn yellow. Heavy infestations can check growth, spoil flowers and reduce yields on vegetables and fruit. Honeydew makes foliage sticky and allows sooty mould to develop, reducing light reaching leaves. Some aphids can also pass plant viruses between susceptible crops.
Prevention
Check new growth regularly from early spring, especially plants fed heavily with nitrogen-rich fertiliser. Encourage ladybirds, hoverfly larvae and lacewing larvae by growing nectar-rich flowers nearby and avoiding unnecessary disturbance of sheltering areas. Keep plants well watered but not overfed, and remove badly infested shoot tips promptly. Use fine mesh on vulnerable vegetable crops where practical, and deal with ants around pots or beds so predators can reach colonies.
How to manage it
Rub or pinch out small colonies before they spread, then inspect plants every few days. A firm jet of water can dislodge aphids from sturdy plants; repeat if needed and support the plant afterwards. Remove heavily distorted leaves or shoots and put them in household waste. Leave beneficial insects in place, as ladybirds, hoverfly larvae and lacewing larvae often bring numbers down naturally. Wash honeydew from leaves where it is easily reached.
Aphids (Greenfly and Blackfly): frequently asked questions
How do I identify aphids (greenfly and blackfly)?
Look for clusters of soft-bodied, pear-shaped insects, usually 1 to 4 mm long, on shoot tips, flower buds and the undersides of leaves.
How do I prevent aphids (greenfly and blackfly)?
Check new growth regularly from early spring, especially plants fed heavily with nitrogen-rich fertiliser.
How do I get rid of aphids (greenfly and blackfly)?
Rub or pinch out small colonies before they spread, then inspect plants every few days.
General guidance for UK home gardens and allotments, focused on prevention and non-chemical control. For a confirmed diagnosis, the RHS or a local garden centre can help. Page updated 19 Sep 2026.