Aphids on Houseplants
Aphids are small pear-shaped soft-bodied insects that cluster on new growth and the undersides of leaves, sucking sap and excreting honeydew. They reproduce rapidly indoors and can transmit plant viruses, but are also the easiest of the common pests to knock back.
How to identify aphids
Small (1–3 mm), pear-shaped, soft-bodied, usually green but can be black, yellow, pink, or grey. Often found in dense clusters on new growth, flower buds, and leaf undersides.
Damage to look for
Distorted or curled new growth, sticky honeydew on lower leaves and surfaces, sooty mold growing on the honeydew, yellowing on infested tissue.
Life cycle (why they spread so fast)
Indoors, aphids reproduce parthenogenetically (no males needed) — a single female can produce 50–80 offspring in her ~30-day life. Populations explode without intervention.
How to get rid of aphids
- Rinse the plant with a strong stream of water to dislodge most of the colony.
- Spray remaining aphids with insecticidal soap, repeat every 5–7 days for 2–3 cycles.
- For heavy infestations, neem oil or horticultural oil (1%) works well — spray all surfaces, including new growth.
- Severe cases on tough-leaved plants can be wiped down with a soft cloth dipped in alcohol-water solution.
How to prevent aphids
- Inspect new growth weekly — aphids prefer young soft tissue.
- Avoid heavy nitrogen fertilizer — lush growth attracts aphids.
- Quarantine new plants for 2–3 weeks.
Per-species treatment guides
Treatment varies slightly by plant. Find your species below for a dedicated guide.
Source: UC IPM — Aphids