Whitefly set up home and live out their lives on the underside of leaves. As adults they are about 2mm long with white wings, which give them their name. The adults lay eggs which hatch into yellowy green scale-like nymphs which become pupae before reaching adulthood. Three generations living under the same leaf and all of them feeding on the sap of the plant.
In the garden, Whitefly are fond of Azaleas, Rhododendron, Honeysuckle - not forgetting Cabbages. Indoors, in the conservatory or in the greenhouse they’re less picky and will feed on many houseplants, ornamentals and vegetables. There’s usually little visible damage to the plants themselves, but brush past an infested plant or close the greenhouse door sharply and you’ll see a ‘white cloud’ rise from the underneath the leaves. If the infestation is left untreated things change.
They feed on sap and they excrete a sticky honeydew which drops on to lower foliage. A black sooty mould develops. Very unsightly. Whitefly can also spread viruses.
Treatment and control
Spray fruit and vegetables with a natural insecticide: Pyrethrin based insecticides will control Whitefly and other plant pests. An example is BugClear Gun! for Fruit & Veg. For best results spray thoroughly as Pyrethrins kill on contact.
Spray ornamentals with a systemic insecticide: For treatment of ornamental plants and certain listed fruit and vegetable crops (see the list on the product label), spray with a systemic insecticide. Examples are BugClear Ultra and Bugclear Ultra Gun!.
Greenhouses and conservatories: In greenhouses and conservatories ‘sticky’ traps can help control.