Scale Insects on Houseplants: Identification and Treatment
Priya Hollis · Oct 24, 2026 · 5 min read
Quick answer
Small brown bumps on stems that do not wipe off easily are often scale. Persistence is the key to beating them.
Scale insects attach themselves to stems and the undersides of leaves, protected by a waxy or shell-like cover. They are easy to mistake for part of the plant.
Like mealybugs, they suck sap and leave sticky honeydew behind.
1 How to recognise scale
- ✓Raised brown, tan, or grey bumps along stems and leaf veins
- ✓Sticky leaves or surfaces under the plant
- ✓Black sooty mould growing on the honeydew
- ✓Yellowing leaves and weak growth
2 Removing them
Isolate the plant. Scrape scale off gently with a fingernail or soft toothbrush, or wipe with a cotton pad dipped in rubbing alcohol. Then spray with insecticidal soap or horticultural oil, which smothers young crawlers that have not yet formed a shell.
3 Keep checking
Scale has several life stages, so repeat treatment weekly for at least six weeks. Check plants carefully under leaves and in crevices. Badly infested plants may be easier to replace, or cut back hard, than to rescue.
4 Plants most at risk
Ficus, citrus, palms, ferns, orchids, and succulents are frequent targets. Check new plants carefully before bringing them home.
This is general gardening information. Results depend on your climate, soil, and conditions. Follow label directions for any fertiliser or treatment, and check whether plants are toxic to pets or children before bringing them home.