Aphids are among the easier houseplant pests to beat. They sit out in the open on soft new growth, and water alone removes many of them. The catch is speed: indoors they breed all year, so a few aphids on Monday can be a colony by the next week.

This page covers identification, the life cycle, damage, and control from least toxic up. For a side-by-side view of all the common pests, see our houseplant pest overview.

How to identify aphids

UC IPM describes aphids as small, soft-bodied insects with pear-shaped bodies and long legs and antennae. Colour depends on species and host: green, yellow, brown, red or black. A few species look woolly because they coat themselves in white or grey wax.

Clemson puts most houseplant aphids at about 1.5–3 mm (1/16–1/8 in) long. Adults may or may not have wings. UC IPM says winged forms appear mostly when colonies get crowded, which is how they spread to the next plant.

Three checks confirm aphids:

  1. Cornicles. UC IPM says most species have a pair of tube-like structures pointing backward from the rear of the body. Their presence separates aphids from all other insects. A 10× hand lens helps.
  2. White cast skins. Aphids shed their skin as they grow. UC IPM and the RHS both point to these pale, empty husks on leaves below a colony.
  3. Behaviour. UC IPM notes most aphids do not move quickly when disturbed, unlike leafhoppers and other look-alikes.

Look-alikes

What you seeMore likelyHow to tellSource
Tiny white insects that fly up when the plant is touchedWhitefliesAdults are winged and flutter; the young are flat and immobileClemson, UC IPM
White, cottony clusters in leaf jointsMealybugsWax-covered, segmented, slow; UC IPM says woolly aphids are a common mix-upUC IPM
Brown or tan bumps that never moveScale insectsNo visible legs; flake off with a fingernailUC IPM, Clemson
Crusty, golden-brown, swollen aphidsParasitised aphids (“mummies”)Not a new pest; a sign of natural controlUC IPM

If you see flying white insects, read our hoya whitefly guide instead.

Life cycle: why numbers jump so fast

UC IPM explains that most aphids in mild conditions reproduce without mating. Adult females give birth to live young, often as many as 12 a day. Young aphids (nymphs) moult about four times and there is no pupal stage.

In warm weather, many species go from newborn to reproducing adult in seven to eight days. Colorado State says aphids common on houseplants can complete a generation in two to three weeks. The RHS notes that some aphids stay active all year on indoor plants rather than overwintering as eggs.

Generations overlap. A single spray rarely finishes the job.

Which houseplants get aphids

The RHS says almost any plant can host aphids, houseplants included. Extension sources name some regular targets:

  • Hibiscus, chrysanthemums, ornamental peppers and herbs (Colorado State)
  • Ivy, herbs and hibiscus, with distorted new growth (Penn State)
  • Gardenia, shown with green peach aphids in UC IPM’s houseplant pest note

Colorado State lists green peach aphid, potato aphid, cotton/melon aphid and chrysanthemum aphid as common on houseplants. Plants that spent summer outdoors are a frequent source.

Damage signs

Check new shoots, flower buds and leaf undersides first. Clemson says aphids usually feed there, and some species feed on roots.

  • Curled, puckered or distorted new leaves. UC IPM says some species inject a toxin that makes leaves curl.
  • Yellowing and stunting. Clemson lists yellow, misshapen leaves, stunted growth and deformed buds.
  • Honeydew. Leaves turn shiny and sticky, and so can the table underneath. Penn State notes you may see honeydew before you see the insects.
  • Sooty mould. A black, powdery film that grows on the honeydew. Penn State says it shades the leaf and inhibits photosynthesis.
  • Ants. UC IPM says ants feed on honeydew and protect aphids from their natural enemies.

Sticky leaves on a citrus? Aphids are one of four likely culprits. See our indoor citrus honeydew guide.

Control, least toxic first

Start by moving the plant away from your others. UC IPM says to isolate an infested plant immediately and wash your hands after handling it.

1. Rinse them off

Colorado State calls a vigorous jet of water particularly effective for aphids, because they are easily dislodged. UC IPM says most dislodged aphids cannot get back onto the plant, and the honeydew washes off too. For a sturdy plant, use the shower or sink and cover the leaf undersides.

Iowa State recommends combining rinsing with insecticidal soap and selective pruning rather than relying on one method.

2. Prune and squash

Where aphids sit on a few curled leaves or shoot tips, UC IPM says pruning them out may be the best control. Bag the clippings. The RHS says you can squash small colonies between finger and thumb.

3. Spot-treat with a swab

For a minor infestation, Clemson suggests wiping aphids off with a cotton swab dipped in rubbing alcohol. Keep the alcohol on the insects, not the leaf.

4. Insecticidal soap or horticultural oil

UC IPM calls soaps and oils the best choices for most aphid problems. Oils include petroleum-based horticultural oil and plant oils such as neem. Follow the label for your plant and pest.

  • Coverage is everything. These products work by smothering, so wet the tops and undersides of infested leaves (UC IPM).
  • Repeat. UC IPM says they kill only aphids present on the day you spray. Clemson says treatment usually has to be repeated several times.
  • Prune curled leaves first. Aphids inside them escape contact sprays (UC IPM).
  • Avoid stress and heat. UC IPM says not to use soaps or oils on water-stressed plants or above 32 °C (90 °F). Test a small area several days ahead.
  • Check sensitive plants. Clemson lists jade plant, begonia, dieffenbachia, schefflera, maidenhair fern and some palms among houseplants sensitive to insecticidal soap.

Our neem oil guide and neem oil vs insecticidal soap comparison cover choosing between them.

5. Systemic products, last resort

UC IPM’s houseplant pest note lists a soil-applied systemic or a labeled foliar insecticide only as a last resort. Clemson says imidacloprid granules on the soil control aphids. Colorado State calls imidacloprid particularly effective and notes green peach aphid is often resistant to other insecticides.

Use only a product labeled for indoor use on your plant species. UC IPM warns imidacloprid can harm pollinators and natural enemies, and says not to apply systemics to plants in bloom or about to bloom. In California, UC IPM notes that as of January 2025 systemic aphid insecticides are sold only to licensed professionals. Check what is legal where you live.

When to discard the plant

Aphids rarely justify it. UC IPM says aphids seldom kill a mature plant. Consider discarding only when the plant is badly damaged and keeps getting reinfested. Colorado State notes that seriously infested plants can infest others.

Prevention and quarantine

  • Inspect before you buy. UC IPM says to check leaf surfaces, leaf bases and flower stalks, and reject infested plants.
  • Quarantine new arrivals. Colorado State suggests a separate area for at least three weeks; Clemson suggests six weeks with weekly checks.
  • Check plants that summered outdoors before bringing them in (UC IPM).
  • Wash smooth-leaved plants every two to three weeks, as Clemson recommends.
  • Go easy on nitrogen. UC IPM says high nitrogen favours aphid reproduction.
  • Use yellow sticky cards to catch winged aphids. Colorado State says trapping alone will not end an infestation.

Once honeydew stops appearing, wipe remaining sooty mould off with a damp cloth (RHS). For other pests, see spider mites on houseplants.

References