Scale insects
Brown, waxy bumps that scrape off and leave a sticky film are scale insects, not edema.
Diagnosis
Scale insects
What's happening
Scale are small sap-sucking insects that hide under a hard brown or tan shell, clustering along stems and leaf veins where they look almost like part of the plant. As they feed they weaken growth and excrete sticky honeydew, which leaves a shiny film on the leaves below and can attract sooty mold. Unlike edema, the bumps lift off when you scrape them.
How to fix it
Isolate the plant from your others right away. Scrape off the visible scale with a fingernail or a cotton swab dipped in rubbing alcohol, then treat the whole plant — stems, leaf undersides, and crevices — with horticultural neem oil, repeating every 7–10 days for several weeks to catch newly hatched crawlers. Wipe away any sticky honeydew as you go and keep checking new growth until it stays clean.
What fixes it
- Neem oil for pests — Neem oil smothers scale and the crawlers that hatch after; 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.
Read the full Baby Rubber Plant care guide →
Reviewed June 2026 · how we check this