Houseplant Pests
Spider mites, mealybugs, scale, aphids, thrips and bugs in the soil: how to identify them and what actually works.
Houseplant pests are best handled in this order: identify the pest from the signs it leaves, isolate the plant, remove as many insects as you can by rinsing or wiping, then treat with insecticidal soap or horticultural oil labeled for the plant, repeating every 5 to 10 days for 3 to 4 weeks because sprays do not kill eggs. Quarantining new plants for a few weeks prevents most infestations in the first place.
In this section
2 articles
Mealybugs on houseplants: how to identify and get rid of them
Mealybugs look like white cotton in leaf axils. How to confirm them, kill them with alcohol swabs, soap and oil, check for root mealybugs, and stop them coming back.
Spider mites on houseplants: how to spot them and get rid of them
Spider mites show up as pale stippling and fine webbing under leaves. The white-paper test, life cycle by temperature, a day-by-day treatment plan and what fails.
Most pests arrive on a new plant or on plants brought in from a summer outdoors. Once inside, warm rooms and no natural enemies let them breed year round. The good news: the common ones are well studied, and the same few methods work for most of them. UC IPM's Houseplant Problems Pest Notes and Iowa State University Extension are the backbone of this section.
Identify the pest by its signs
| What you see | Pest | What works | Treatments |
|---|---|---|---|
| Fine webbing, tiny pale speckles, dull or bronzed leaves | Spider mites | Strong rinse, raise humidity, insecticidal soap or horticultural oil on leaf undersides | Every 5 to 7 days for 3 to 4 weeks |
| White cottony clumps in leaf joints, sticky leaves | Mealybugs | Alcohol on a cotton swab, then soap or oil; systemic for heavy cases | Weekly for 4+ weeks |
| Brown or tan bumps along stems and veins, sticky leaves | Scale | Scrape or wipe off, then horticultural oil | Every 10 to 14 days, several rounds |
| Clusters of small green, black or pink insects on new growth | Aphids | Rinse off, insecticidal soap | Weekly, 2 to 3 rounds |
| Silvery streaks, black specks, distorted new leaves | Thrips | Rinse, insecticidal soap, blue or yellow sticky traps | Every 5 to 7 days for 3 to 4 weeks |
| Tiny white moths flying up from leaf undersides | Whiteflies | Yellow sticky traps, soap or oil on undersides | Every 5 to 7 days |
| Small dark flies around the pot, larvae in wet soil | Fungus gnats | Drier soil, sticky traps, larval treatment | See PestFact |
| Small bugs crawling in the soil | Bugs in soil | Depends on the bug; many are harmless | Identify first |
Fungus gnats: see PestFact
Fungus gnats are the most common houseplant "bug" of all, but they are a household pest topic, and our sister site PestFact covers them in depth: fungus gnats explained, including how to break the larval cycle in the soil. The short version for plant owners: they breed in soil that stays wet, so letting the top inch or two dry between waterings is the most important step.
A protocol that works for most pests
- Isolate the plant as soon as you see pests and inspect every plant that stood near it.
- Remove what you can: prune the worst leaves, rinse the plant in the shower or sink, and wipe mealybugs and scale off with a cotton swab dipped in rubbing alcohol.
- Spray insecticidal soap or horticultural oil (including neem oil) labeled for houseplants, covering leaf undersides, stems and leaf joints until wet.
- Repeat on the interval in the table for 3 to 4 weeks. Sprays do not kill eggs, and a single treatment just resets the clock.
- Keep checking weekly for a month after the last pest is gone before returning the plant to its spot.
UC IPM recommends trying soap or horticultural oil before other insecticides, avoiding broad-spectrum, long-lasting products indoors, and spraying outdoors when possible so the residue stays out of the house. For stubborn mealybugs and scale, a soil-applied systemic insecticide is an option, but Iowa State cautions that granules may be a poor choice where pets or children dig in pots. See systemic insecticides and neem oil for details.
Safety indoors
- The label is the law: use only products that list houseplants or your plant, and follow the rates.
- Test any spray on one leaf and wait 24 hours. Ferns, some succulents and fuzzy-leaved plants are easily damaged by soaps and oils.
- Spray in a ventilated room or outside, wear gloves and keep pets and children away until leaves are dry.
Prevention
Inspect plants before you buy, including leaf undersides and the root ball. Keep new plants apart from your collection for two to three weeks, check plants coming back indoors in fall, and rinse foliage occasionally; UC IPM notes regular washing prevents many infestations. A strong plant in the right light recovers much faster, so fix care problems too: see houseplant problems and care basics.
Frequently asked questions
What are the tiny white bugs on my houseplant?
Why are my plant's leaves sticky?
Does neem oil work on houseplant pests?
Can I use rubbing alcohol on mealybugs?
How do I get rid of fungus gnats?
Should I throw away an infested plant?
Sources
Facts on this page were checked against these publications. Links open in a new tab.
- Iowa State University Extension yardandgarden.extension.iastate.edu
- pestfact.com pestfact.com
- UC Statewide IPM Program ipm.ucanr.edu