Plant care guide
Croton Pests: Spider Mites, Mealybugs, Scale and Thrips
Updated
What pests attack a Croton?
Spider mites are the pest most likely to trouble an indoor croton, especially in dry air. Mealybugs, scale insects and thrips are the other common ones. Each leaves a different sign, so identify the pest before you treat.
What to do first
Isolate the plant and check leaf undersides and leaf joints with a hand lens. Rinse off mites, wipe off mealybugs with alcohol on a swab, scrape off scale, then follow up with insecticidal soap and repeat.
Crotons (Codiaeum variegatum) are grown for their bold, multicoloured leaves, so pest damage shows quickly. University of Wisconsin–Madison Extension says croton has few pest problems beyond the usual houseplant insects: mealybug, spider mite and scale. UF/IFAS adds thrips to the list. Spider mites are the one to watch most closely. NC State Extension notes that spider mite susceptibility sometimes limits how long crotons are used in indoor plantings.
Treatment depends on the pest. Start with identification.
Identify the pest
| What you see | Likely pest | Where to look |
|---|---|---|
| Fine pale speckling, faded or bronzed leaves, fine webbing | Spider mites | Leaf undersides, with a hand lens |
| White, cottony clusters; sticky leaves | Mealybugs | Leaf undersides, leaf joints, stem crotches |
| Small, flat or domed bumps that don’t move; sticky leaves | Scale insects | Stems and leaf undersides |
| Silvery or speckled leaves, tiny slender insects | Thrips | Leaf surfaces; tap leaves over white paper |
Spider mites
Clemson Cooperative Extension’s houseplant pests factsheet says damage is often the first sign. Look for light speckling on the upper leaf surface and an overall faded look. Heavier infestations leave silky webbing. UC IPM’s spider mite pest note adds that leaves may bronze, then yellow and drop. To confirm, shake a leaf over white paper and watch for tiny moving dots.
Mealybugs
Clemson describes mealybugs as small, pale insects covered in white, waxy material that makes them look cottony. They gather on lower leaf surfaces and in leaf axils. UC IPM’s mealybug pest note says they excrete sticky honeydew, which can grow black sooty mould.
Scale insects
Clemson says scales look like small, immobile bumps without visible legs, sometimes like fish scales stuck to the plant. They sit on stems and leaf undersides. Soft scales also produce honeydew.
Thrips
Clemson says thrips feeding gives leaves a silvery or speckled look, similar to mite damage. Blowing gently on leaves makes thrips move, so they are easier to see.
Treat the infestation
Before you start: croton sap irritates skin and eyes, and NC State warns it stains fabric permanently. The RHS advises wearing gloves when handling or pruning crotons.
- Isolate the plant. Clemson advises keeping an infested plant away from other houseplants until the pest is controlled. That may take several weeks.
- Remove the worst growth. Cut off heavily infested shoots or leaves and bag them.
- Treat by pest:
- Spider mites: spray sturdy plants forcefully with water, including leaf undersides, to dislodge mites and break up webbing. Clemson says repeated sprays help. UF/IFAS suggests taking indoor crotons outdoors into shade to wash them, which also helps manage spider mites.
- Mealybugs: wipe them off with a cotton swab dipped in rubbing alcohol. UC IPM says to use a solution of 70% or weaker isopropyl alcohol. Test it on a small area first.
- Scale: scrape early infestations off with a fingernail, Clemson advises. Adults are protected by their waxy cover, but the mobile young (crawlers) are vulnerable to sprays.
- Thrips: rinse the leaves with water.
- Follow up with insecticidal soap. Clemson says it works best on soft-bodied pests: mealybugs, young scales, thrips and spider mites. Soap only kills on contact, so cover leaf undersides. Repeat, because eggs and hidden pests survive one round. UC IPM advises against using soaps or oils on water-stressed plants or above 32 °C (90 °F). Test on a few leaves first.
- Check weekly. Clemson suggests a 10× hand lens on leaf undersides. Keep going until no live pests remain.
UC IPM warns that some broad-spectrum insecticides can make spider mite problems worse. That’s another reason to start with water, soap or oil.
Make your croton less inviting
Raise humidity and water steadily. The RHS croton guide says crotons need high air humidity and recommends a tray of damp pebbles under the pot. NC State also suggests a bed of wet pebbles indoors. UC IPM notes that water-stressed plants are especially susceptible to mite damage.
Keep leaves clean. The RHS suggests wiping croton leaves occasionally with a damp cloth. Clemson notes that regular washing discourages pests.
Avoid overfeeding. UC IPM says excess nitrogen fertilizer stimulates soft new growth that mealybugs prefer.
Inspect new plants. Clemson advises checking new plants before buying. Keep new arrivals apart from your other plants for six weeks.
Give steady conditions. Wisconsin recommends bright, indirect light, 16–29 °C (60–85 °F), and protection from drafts. A plant that isn’t stressed copes better with a small infestation.
For confirming and breaking a mite cycle on any houseplant, see spider mites on houseplants. For croton light needs, read croton light requirements.
Related guides
Other croton problems we cover: leaf drop, overwatering, brown tips.
References
- NC State Extension Gardener Plant Toolbox: Codiaeum variegatum
- University of Wisconsin–Madison Extension: Croton, Codiaeum variegatum
- UF/IFAS Gardening Solutions: Crotons
- Clemson Cooperative Extension: Common Houseplant Insects & Related Pests
- UC IPM Pest Notes: Spider Mites
- UC IPM Pest Notes: Mealybugs
- Royal Horticultural Society: Codiaeum (croton) growing guide
How this guide was put together: NC State Extension, University of Wisconsin–Madison Extension, UF/IFAS Extension, Clemson Cooperative Extension, UC IPM and Royal Horticultural Society guidance.