pests diseases
How to get rid of whitefly on plants — full guide
Whiteflies are tiny white moth-like bugs that fly up in a cloud when you disturb a plant. Kill them with yellow sticky traps, insecticidal soap, and neem over 3-4 weeks.
How to get rid of whitefly on plants — full guide
Whiteflies are easy to miss until you brush a leaf and a flurry of tiny white specks lifts off — by then a colony is usually well established on the undersides of the leaves. They are sap-suckers like aphids and scale insects, and like both they excrete sticky honeydew that feeds black sooty mould. This guide covers identification, the lifecycle that makes them stubborn, the full removal protocol, and how to keep them out.
Confirm before you treat: Photograph the underside of an affected leaf in Growli — I'll tell you whether it's whitefly, mealybugs, or a fungus gnat problem, because each needs a different fix.
What whiteflies are
Whiteflies are not true flies — they are small winged insects more closely related to aphids, mealybugs, and scale (all in the order Hemiptera). Adults are 1-2 mm long with powdery white wings held roof-like over the body. Two species cause most indoor and greenhouse damage:
- Greenhouse whitefly (Trialeurodes vaporariorum) — the most common on houseplants and in greenhouses worldwide.
- Sweetpotato / silverleaf whitefly (Bemisia tabaci) — more common on vegetable crops and in warm climates.
The two are hard to tell apart as adults; the reliable difference is in the pupal (late nymph) stage — the greenhouse whitefly pupa is raised off the leaf with a fringe of fine hairs around its edge, while the Bemisia pupa sits flat against the leaf with no fringe (Source: UC IPM — Whiteflies).
How to identify whitefly
Five tells:
- A cloud of tiny white insects lifts off when you brush or shake the plant, then quickly resettles on the leaf undersides.
- Clusters of white specks on the undersides of leaves — a mix of adults, oval nymphs (which look like tiny translucent scales), and yellow eggs often laid in a circle or arc.
- Sticky honeydew on lower leaves and surfaces below the plant.
- Black sooty mould growing on the honeydew.
- Yellowing, stippling, and wilting leaves, with weak growth in a heavy infestation.
Common indoor and garden hosts: tomatoes, peppers, fuchsia, hibiscus, poinsettia, brassicas, and many soft-leaved houseplants.
The lifecycle (why they're stubborn)
Whiteflies develop from egg to adult in about 21-26 days at 81°F / 27°C, and faster in warm rooms or greenhouses, so populations build quickly when it's warm and natural enemies are absent (Source: UC IPM — Whiteflies). Females lay eggs on leaf undersides; these hatch into mobile "crawlers" that settle, flatten into scale-like nymphs, and feed in place before pupating into new adults.
The practical consequence is the same as with mealybugs and scale: a single spray kills the adults and exposed nymphs but not the eggs, which keep hatching for roughly two weeks. You must repeat treatment every 5-7 days for 3-4 weeks to catch each new wave before it can lay more eggs.
How to get rid of whitefly — 4 steps
- Isolate and knock down the population. Move the plant away from others. Rinse leaf undersides with a firm spray of water, or vacuum the adults early in the morning when they are sluggish, to remove the bulk of the colony before spraying.
- Hang yellow sticky traps. Whiteflies are strongly drawn to yellow. Traps placed just above the foliage catch flying adults, lower the breeding population, and let you monitor whether numbers are falling.
- Spray leaf undersides every 5-7 days. Use insecticidal soap or neem oil, coating the undersides thoroughly where eggs and nymphs live. Neem also disrupts development of the immature stages. Repeat for 3-4 weeks to break the egg-hatch cycle. UC IPM recommends insecticidal soaps and oils and warns against broad-spectrum insecticides that kill the whitefly's natural enemies and make outbreaks worse (Source: UC IPM — Whiteflies).
- Remove what you can't save. Prune and bag heavily infested lower leaves. If a plant is overwhelmed, removing it protects the rest of your collection.
In greenhouses, the parasitic wasp Encarsia formosa is an effective biological control released early in the crop cycle — less practical for a few houseplants, but worth knowing for larger setups.
How to prevent whitefly
- Inspect new plants and quarantine them for 2-3 weeks before adding them to your collection — whitefly usually arrives on a new purchase.
- Check leaf undersides weekly, especially on tomatoes, fuchsia, and other favourites.
- Hang a yellow sticky trap as an early-warning monitor near susceptible plants.
- Avoid over-fertilising — soft, nitrogen-rich new growth attracts sap-suckers.
- Protect natural enemies by not reaching for broad-spectrum insecticides; ladybirds, lacewings, and parasitic wasps all help keep whitefly down.
Common problems
| Symptom | Likely cause | Fix |
|---|---|---|
| White cloud when disturbed | Adult whiteflies | Sticky traps + soap/neem on undersides |
| Sticky leaves + black film | Honeydew + sooty mould | Treat whitefly; wipe mould off with damp cloth |
| Numbers not dropping after one spray | Eggs still hatching | Repeat every 5-7 days for 3-4 weeks |
| Yellowing, weak growth | Heavy sap loss | Knock down population fast; remove worst leaves |
For the rest of the diagnostic library — other sap-suckers, leaf-spot fungi, and the honeydew-fed moulds — see the common houseplant diseases hub.
Related articles
- Aphids on plants — the other common sap-sucking cloud pest
- How to get rid of mealybugs — white cottony sap-suckers, similar repeat-treatment logic
- Scale insects — armored sap-suckers that also produce honeydew
- Fungus gnats — the soil-dwelling flies whiteflies are often confused with
- Common houseplant diseases — the full diagnostic hub
Reviewed and updated by the Growli editorial team. For questions about anything here, open Growli and ask — or email hello@getgrowli.app.
Frequently asked questions
What are whiteflies?
Whiteflies are tiny (1-2 mm) white, moth-like sap-sucking insects in the order Hemiptera — relatives of aphids, mealybugs, and scale, not true flies. The two most common pest species are the greenhouse whitefly (Trialeurodes vaporariorum) and the sweetpotato/silverleaf whitefly (Bemisia tabaci). They cluster on leaf undersides, fly up in a cloud when disturbed, and excrete sticky honeydew that feeds black sooty mould.
How do I get rid of whiteflies on my plants?
Use a 3-4 week combined attack: hang yellow sticky traps to catch adults, rinse or vacuum the bulk of the colony off leaf undersides, then spray insecticidal soap or neem oil on the undersides every 5-7 days. Repeat treatment is essential because eggs keep hatching for about two weeks — one spray never clears them. Remove heavily infested leaves and isolate the plant from your collection.
Why do whiteflies keep coming back?
Because eggs and nymphs survive the first treatment. Whiteflies develop from egg to adult in about 21-26 days, and eggs on leaf undersides keep hatching for roughly two weeks after you spray. If you treat once and stop, the next wave matures and lays more eggs. Spraying every 5-7 days for 3-4 weeks breaks the cycle by killing each new generation before it can reproduce.
What attracts whiteflies to plants?
Warm conditions, soft nitrogen-rich new growth from over-fertilising, and susceptible host plants like tomatoes, fuchsia, hibiscus, poinsettia, and brassicas. They most often arrive on a newly bought plant, which is why quarantining new plants for 2-3 weeks is the single best prevention. Dusty conditions and the absence of natural predators also let populations build.
Are whiteflies harmful to plants?
Yes. Whiteflies pierce leaves and drain sap, which causes yellowing, stippling, weak growth, and wilting in heavy infestations. Their honeydew coats leaves and feeds black sooty mould that further blocks light. Some species also transmit plant viruses. A light infestation is cosmetic and easy to control; a heavy one left untreated can seriously weaken or kill a plant.
Do yellow sticky traps work for whiteflies?
Yes — whiteflies are strongly attracted to yellow, so sticky traps placed just above the foliage catch flying adults, reduce the breeding population, and let you monitor whether numbers are falling. Traps alone won't clear an infestation because they don't kill eggs or nymphs, but combined with insecticidal soap or neem sprays on the leaf undersides they're a valuable part of the control plan.
Are whiteflies the same as fungus gnats?
No. Whiteflies are white, settle on leaf undersides, and fly up in a cloud when the plant is shaken — they feed on leaf sap. Fungus gnats are small dark-grey flies that hover around the soil surface and whose larvae live in damp potting mix feeding on organic matter and roots. Whiteflies are treated on the foliage; fungus gnats are treated by letting the soil dry and targeting the larvae. See our separate fungus gnats guide.