Scale insects: how to spot and manage them

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Scale are sap-suckers that look like little bumps or shells stuck to stems and leaves — many people mistake them for part of the plant. Like mealybugs, they drip honeydew and bring on sooty mould.

Also known as: scale.

How do I spot them?

1. Raised brown, black or white bumps along stems and leaf veins that don't move.
2. Sticky honeydew and black sooty mould, often with ants about.
3. Yellowing leaves and dieback of affected branches.

Which plants do they target?

Growing any of these? See our guides to tomatoes.

Citrus is the classic host, along with many veg, herbs and ornamentals.

How do I manage them safely?

1. Rub or scrub small numbers off with a soft brush or your thumbnail.
2. Horticultural oil smothers them — thorough coverage is the trick; insecticidal soap and neem oil help too.
3. Prune out badly affected wood, encourage ladybirds, and discourage the ants.

For the bigger picture, see our guide to managing pests and problems safely.

Plan your patch: our free garden calendar shows what to plant now where you live. Ready to grow? Browse our raised garden beds or build your own with the garden bed builder.

Image: Neb, CC BY-SA 4.0, via Wikimedia Commons.