COMMON NAME

Silverleaf whitefly

Order

Suborder

Family

Genus

Species

Alias

Hemiptera

Sternorrhyncha

Aleyrodidae

Bemisia tabaci

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Description

Whiteflies are tiny, white, moth-like insects which are related to aphids. Their bodies and wings are covered in a white powdery wax. The silverleaf whitefly is virtually identical to the greenhouse whitefly, but is slightly smaller and the wings of the silverleaf whitefly do not quite meet over the body whereas the greenhouse whitefly overlaps its wings slightly. The small eggs are laid randomly under the leaves, and are pale yellow turning a light brown when nearing hatching. The nymphs look like scale, white or with a green tinge in colour. When the silver whitefly moults the skins are silvery, perhaps giving it its name.

Adult size: 1 mm

Out and about

They breed very quickly during spring and summer. They like tropical, subtropical climates but will survive in temperate regions. Widespread in Queensland and Western Australia.

Reproduction and Life cycle

Each female can lay up to 200 eggs, which hatch in 1 week. Their life cycle ranges from 4-8 weeks depending on weather conditions, being shorter in warmer weather. They can produce many generations through the year.

To deter

To control

- They are attracted to yellow, so can be trapped by smearing a yellow surface with Vaseline or other sticky spread - Citronella spray will deter adults from landing on plant - White oil sprayed regularly, on the nymphs and the flies if possible, will smother them - Spray with neem oil - Spray with pyrethrum

Plants to repel

Artimisias / Basil / Thyme Calendula, marigolds, nasturtiums (yellow) and mint can be grown as trap crops (attract whitefly away from food crops)

Plants to attract

Predators

Lady beetles / Lacewing / Encarsia wasp / Predatory mite / Hover fly / Damsel bug

Why they are a Pest

The silver whitefly is more of a pest than other whitefly species because it has a quicker reproductive rate, is more resistant to insecticides, and has a larger range of host plants. Both adults and larvae are sap suckers of leaves, causing leaf loss, wilting and stunted growth. Their larvae also excrete honey dew which attracts ants and causes sooty mould. Like aphids and scale they can spread viruses. They are usually present in great numbers and when disturbed they will fly up in a cloud. They attack a wide range of plants particularly liking hibiscus, herbs and vegetable seedlings. Other signs of whitefly attack are silvering and yellowing of the leaves, uneven ripening of fruit and the presence of sooty mould.

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