How do I get rid of houseplant pests?
Identifying the four common indoor pests and treating each, plus the isolation that stops them spreading.
- Difficulty
- beginner
- Time
- 45 min
- Read
- 2 min
Short answer
Isolate the affected plant immediately, then identify what you have — fungus gnats, spider mite, mealybug or scale all need different treatment. Wiping leaves and improving conditions handles most infestations without chemicals.
Indoor pests spread quickly because plants sit close together in stable warm conditions with no predators. Isolation is the first action regardless of what the pest turns out to be.
What you'll need
- Cloth or cotton buds
- Insecticidal soap (optional)
- Sticky traps (optional)
- Magnifying glass (optional)
Step by step
- Isolate the plant immediately.Away from every other plant, before identifying anything. Indoor pests spread between touching or adjacent plants within days.
- Identify what you have.Small dark flies around the compost are fungus gnats. Fine webbing and stippled leaves is spider mite. White fluffy spots are mealybug. Brown limpet-like bumps are scale.
- For fungus gnats, let the compost dry out.They breed in wet compost. Letting the top few centimetres dry between waterings breaks the cycle, and yellow sticky traps catch the adults.
- For spider mite, raise the humidity and wash the leaves.They thrive in dry air. Shower the plant, wipe both sides of every leaf, and increase humidity. Persistent infestations need repeated treatment.
- For mealybug, dab each one with alcohol.A cotton bud dipped in rubbing alcohol dissolves their protective coating. Tedious but effective, and it must include leaf joints and undersides.
- For scale, scrape them off physically.Their shell protects them from sprays. Scrape with a fingernail or an old toothbrush, then treat the plant to catch the mobile juveniles.
- Treat repeatedly over several weeks.Eggs hatch after treatment. One application never clears an infestation — repeat weekly for at least a month.
- Improve the conditions.Most indoor pest problems take hold on stressed plants. Correct light, water and humidity make the plant far more resistant.
Tips
- Check new plants carefully before bringing them home, and keep them separate for a couple of weeks. Most infestations arrive on a new purchase.
- Wiping leaves regularly is both good for the plant and the best early detection. You notice problems while they are still small.
- Insecticidal soap or neem oil are effective on most soft-bodied pests. Test on one leaf first, since some plants are sensitive.
Common mistakes
- Not isolating the affected plant — Indoor pests spread between adjacent plants within days. Isolation before diagnosis is the first action.
- Treating once and stopping — Eggs hatch after treatment. Weekly repetition for at least a month is what actually clears an infestation.
- Spraying scale insects — Their hard shell protects them. They must be physically scraped off first, then the plant treated for the juveniles.
Questions people ask
What are the tiny flies around my houseplants?
Fungus gnats, breeding in permanently wet compost. Let the top few centimetres dry out between waterings and use yellow sticky traps for the adults.
How do I get rid of spider mites?
They thrive in dry air. Shower the plant, wipe both sides of every leaf, raise the humidity, and repeat weekly for several weeks since eggs hatch after treatment.