Scale Insects on Spider Plant — Bumps Along the Midrib and Stolons
Spider Plant (Chlorophytum comosum)
Symptoms
- brown or tan bumps on leaves and stolons
- sticky leaves
- sooty mold on leaf surfaces
- yellowing near infested areas
- scale deposits on stolons
Causes
Introduction via new plants
Scale insects (various species of Coccidae or Diaspididae) enter indoor collections primarily on newly purchased plants. Crawlers can also travel along stolons from a Spider Plant to neighboring plants, making Spider Plants a potential vector for spreading scale to an entire collection if infested and untreated.
How to Fix It
- 1
Inspect all stolons and leaf midribs carefully — scale on Spider Plants often colonize the undersides of the midrib and the stolon stems rather than the flat leaf blade.
- 2
Scrape scale manually with a soft toothbrush or alcohol-dampened cotton swab, working along each stolon and the underside of each leaf's midrib.
- 3
Apply horticultural oil solution to the entire plant including stolons and spiderettes. Repeat every 10–14 days for 6 weeks.
- 4
Consider removing heavily infested stolons and spiderettes rather than treating them — this reduces the overall pest load faster and prevents crawlers from spreading.
Prevention
- Inspect stolons and the undersides of leaf midribs monthly during maintenance.
- Quarantine new plants for 4 weeks before introducing them near Spider Plants.
- Inspect spiderettes before using them for propagation — scale can be transmitted to new plants.
Quick Summary
| Plant | Spider Plant (Chlorophytum comosum) |
|---|---|
| Category | Pests |
| Likely causes | Introduction via new plants |
| Fix steps | 4 steps — see above |