Tiny whiteflies are sap-sucking insects that can become abundant in vegetable and ornamental plantings, especially during warm weather. Despite their name, whiteflies are not true flies but are in the order Hemiptera, related to aphids, scales, and mealybugs. They derive their name from the mealy white wax covering the adult’s wings and body. Adults are tiny insects with yellowish bodies and four whitish wings. Although adults of some species have distinctive wing markings, many species are most readily distinguished in the last nymphal (immature) stage, which is wingless and lacks visible legs. Whiteflies develop rapidly in warm weather, and populations can build up quickly in situations where natural enemies are ineffective and when weather and host plants favor outbreaks. Large colonies often develop on the undersides of leaves.

There are many species of whiteflies, including the greenhouse whitefly, bandedwinged whitefly, giant whitefly, silverleaf whitefly, and cabbage whitefly, among others. Whiteflies normally lay their tiny oblong eggs on the undersides of leaves, and the eggs hatch into young whiteflies. If infestations of whiteflies are caught early, they can be controlled by washing them off with a sharp spray of water. Make sure to get the undersides of the leaves, as this is where eggs and nymphs hang out. Natural enemies such as lacewings or parasitic wasps can be effective in controlling whiteflies. Castile soap is also an effective treatment for whiteflies.