Small white winged sap-sucking flies that are not true flies. They resemble tiny white moths with a wingspan of 3mm. Whiteflies have become very prevalent in recent years and there are several different types which are major pests for home gardeners.
The Silverleaf Whitefly (Bemisia tabaci) and the Greenhouse Whitefly (Trialeurodes vaporariorium). If the plant is disturbed, a cloud of tiny insects fly out but they soon settle back onto the same plant. Both the adult and juvenile (nymph) whiteflies suck the juices from the plant.
Favoured plants are hibiscus, poinsettia, gerberas, herbs such as sage and mint, vegetable seedlings such as squash, melon, eggplant, cabbage and bean, tomato and broccoli.
Wilting and stunting of new shoots. Can cause silvering and yellowing of leaves (eg. squash) and uneven ripening of tomatoes and sometimes plant death. Sooty mould often accompanies large numbers of whiteflies as they excrete honeydew when feeding on plant tissue.
White fly are best controlled using alternating sprays, as the insects can build up chemical resistance very quickly. Alternating insecticides help to prevent this from happening. Spraying is best done in the early morning or late afternoon when the insects are more restful.