Whitefly control

If you’ve ever brushed past a bunch of plants in your patch and noticed a cloud of tiny white insects appear out of the blue, it’s likely you have a growing population of whitefly. You don’t normally notice them because they are mostly hidden under the leaves, where they feed and breed at their leisure.

Whiteflies are not actually flies; they’re more closely related to aphids and scale. Just like their cousins, these pests are sap-sucking insects that cause a lot of damage to their hosts. When plants are under attack, they look limp or stunted as they struggle to maintain optimum health and vitality. You may detect other telltale signs on affected plants, such as leaf mottling or sooty mould, which grows on the honeydew that the pests produce.

There are many types of whitefly, but the one you will most commonly see in the patch is the greenhouse whitefly (Trialeurodes vaporariorum). It can affect a range of edible plants, including potato, tomato, eggplant, capsicum, cucumber, zucchini, cabbage, lettuce and beans.

Check under leaves to detect and control the pest before a major outbreak occurs. Adults look like tiny white moths and are covered in a powdery wax. Look for their nymphs, too – pale green or translucent scale-like insects, which crawl in their early stage before settling in to fatten up and evolve into a fully fledged flying adult.

For simple and gentle control, apply a horticultural soap spray, which coats and suffocates the insects. You could also use horticultural oil or pyrethrum spray. Take care to cover all parts of the leaves, particularly the undersides, and apply in the cool of the day. You may also need to apply a follow-up spray after a few days to take care of any pests you missed.

Whitefly has some naturally occurring enemies, too, including a predatory mite called Typhlodromips montdorensis that feeds on eggs and nymphs, and the parasitic wasp Encarsia formosa, which lays its eggs in the nymphs. These can be purchased from online suppliers and then introduced into your garden.

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