Scale Insects
Pest · Commonly affects: Camellia, Euonymus, Bay, Citrus, Oleander, Orchid, Fuchsia, Houseplants
Scale insects are sap-feeding pests that sit almost motionless on stems and leaves, often blending in so well that they are mistaken for part of the plant. They affect both garden shrubs and house or greenhouse plants across the UK. Heavy infestations weaken growth and leave sticky honeydew that attracts sooty mould, making early inspection important.
How to identify it
Look for fixed, limpet-like brown, tan or waxy white bumps, usually 2-6 mm across, on stems, leaf undersides and along veins. They do not move when touched, unlike many greenfly and blackfly. Some species produce sticky honeydew, followed by a black, soot-like mould on leaves and nearby surfaces. Freshly hatched young scales may be tiny, pale moving specks, but established bumps are the usual clue.
Damage
Scale insects withdraw sap from shoots and leaves, leading to poor growth, yellowing and dieback when numbers are high. Honeydew makes foliage sticky and supports sooty mould, which shades leaves and spoils ornamental plants. Infested houseplants and greenhouse plants may decline steadily because the pest can breed in sheltered conditions throughout much of the year.
Prevention
Examine stems, leaf undersides and crowded growth whenever buying or bringing in plants, then keep newcomers separate for a short period. Give plants suitable light, watering and ventilation so they are not stressed. Prune congested branches to improve access and airflow, and clean old leaf litter from pots and greenhouse benches. Encourage ladybirds, hoverflies and lacewings outdoors by growing pollen and nectar-rich flowers.
How to manage it
Wipe small colonies from sturdy leaves and stems with a damp cloth, or gently scrape individual scales away with a fingernail. Prune out heavily infested shoots where this will not disfigure the plant, and dispose of them in household waste. Repeat checks every week because newly hatched young can be missed. Wash honeydew from foliage and improve spacing and airflow around affected plants.
Scale Insects: frequently asked questions
How do I identify scale insects?
Look for fixed, limpet-like brown, tan or waxy white bumps, usually 2-6 mm across, on stems, leaf undersides and along veins.
How do I prevent scale insects?
Examine stems, leaf undersides and crowded growth whenever buying or bringing in plants, then keep newcomers separate for a short period.
How do I get rid of scale insects?
Wipe small colonies from sturdy leaves and stems with a damp cloth, or gently scrape individual scales away with a fingernail.
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.