Whiteflies on houseplants
Indoors, whiteflies usually arrive on a new plant and build up unseen on the leaf undersides. On a windowsill it is often quicker to prune out the worst leaves, rinse the plant and spray soap or oil on the leaf undersides, repeating as needed. Encarsia suits a conservatory, sunroom or plant room kept above about 65 °F (18 °C), where the wasps can fly, and it has to go in before the plants are heavily infested.
At a glance
- Damage
- Clouds of white adults, sticky leaves, sooty mould
- Type
- Sap feeding
- Settings
- Under glass, Garden, Indoors
- Threshold
- No numeric threshold; act when honeydew builds up
- Release
- Encarsia formosa
- Rate
- 1–10 /m² per release, repeated until control (Koppert)
How to confirm it
Tap the plant: white adults lift off in a cloud and resettle, wings held flat. Flat, pale oval scales sit under the lower leaves; the oldest are raised and fringed with long wax filaments.
Identification, lifecycle, degree days and every control option are on the full Greenhouse whitefly profile. Not sure it is this pest? Answer four questions about the damage.
Work it out
How many do I need?
Carries Encarsia formosa and houseplants through so nothing is re-entered. Open the calculator →