Scale insects

Small brown bumps along stems and leaf veins, plus a sticky film, point to scale.

Diagnosis

Scale insects

What's happening

Scale insects are sap-feeders that clamp onto stems and leaf undersides under a hard brown shell, so they look more like bumps than bugs. As they feed they excrete sticky honeydew that coats the leaves and nearby surfaces, and heavy infestations sap the plant's vigor and yellow the leaves.

How to fix it

Isolate the plant so the scale doesn't spread. Scrape or pick off the bumps with a fingernail or a cotton swab dipped in rubbing alcohol, then wipe down every leaf and stem. Follow up by spraying the whole plant — tops and undersides of leaves and along the stems — with neem oil, and repeat every 7–10 days for a few weeks until no new bumps appear.

What fixes it

  • Neem oil for pests — Neem oil smothers scale and disrupts its life cycle; reapply every 7–10 days until they're gone.

If that doesn't fix it

This is general guidance based on common symptoms; individual plants vary.

Reviewed June 2026 · how we check this