Spider Mites on String of Pearls — Fine Webbing in the Bead Clusters
String of Pearls (Curio rowleyanus (formerly Senecio rowleyanus))
Symptoms
- fine webbing visible between beads or spanning between adjacent strands
- tiny moving specks on bead surfaces (0.5mm or less; use a magnifying glass)
- beads developing pale stippling — tiny white or pale dots from cell-feeding damage
- overall dull or slightly bronzed appearance on affected strands
Causes
Dry, warm conditions that suit both the plant and the mites
String of Pearls requires low humidity and warm temperatures — exactly the conditions that allow spider mites (Tetranychus urticae) to reproduce rapidly. Mite populations double every week in ideal conditions of 70°F+ and below 40% humidity. The smooth, waxy bead surface does not impede mites the way textured surfaces can; mites establish easily and the early webbing may be mistaken for dust or mineral deposits.
How to Fix It
- 1
Spray the entire plant with a strong stream of lukewarm water, rotating the hanging basket to reach all strand angles. This physically removes a large proportion of the mite population.
- 2
Mix a teaspoon of castile soap into a quart of water and coat every strand, working the spray around each individual bead rather than just the top surface, since a mite tucked against the underside of a bead survives a spray that only hits the exposed side. Three rounds, 5 days apart, catches what the first pass misses.
- 3
A neem oil solution — around 2 teaspoons to the quart with dish soap worked in as an emulsifier — coated over every strand closes out the treatment; the spherical beads' waxy surface actually holds the oil film better and longer than a flat leaf would, so one thorough coating goes further here than on most houseplants.
Prevention
- Wipe strands with a damp cloth monthly — physical removal before populations establish
- Inspect under magnification monthly, especially in winter when heating reduces humidity
- Maintain adequate air circulation; mites establish faster in stagnant air
Quick Summary
| Plant | String of Pearls (Curio rowleyanus (formerly Senecio rowleyanus)) |
|---|---|
| Category | Pests |
| Likely causes | Dry, warm conditions that suit both the plant and the mites |
| Fix steps | 3 steps — see above |