Whiteflies

Whiteflies are tiny pests that can fly and spread quickly between plants. They are sap-sucking insects that can feed on feed on a variety of plants, and are most often found on the underside of leaves in clusters.

Whiteflies will lay eggs on the same plant that they feeding on, and these eggs will quickly hatch into larvae that closely resemble soft scale insects.

Whiteflies will have a dark black pupa fringed with white, resembling an eye. Both the larvae and the adult generally feed in the same area, but the adults will take flight if their leaf is bumped or disturbed.

Like aphids and mealy bugs, whilteflies produce honeydew, a sweet waste fluid, which encourages the growth of sooty mold. Unlike aphids and mealy bugs, ants do not seem to farm whiteflies.

As with most pests, whiteflies generally attack plants that are already unhealthy. Check your plant for additional problems such as root rot from waterlogging, etiolation, or overcrowding. Cultural control methods should be implemented to prevent your plants from becoming unhealthy in the first place.

Symptoms

Leaves appear sticky, and can become covered in sooty mould.

Small flies are seen with white, scale-like masses on th the underside of leaves. The scale-like masses often have a dark center fringed with white, resembling an eye.

Leaves turn yellow, and begin to dry out and wilt.

Preventive and control measures:

Always isolate and inspect newly bought plants for pests before introducing them to your plant collection. Isolate affected plants immediately if pests are found.

Heavily infested plant parts should be pruned as soon as possible. Severe infestations may need the entire plant to be removed. Bag up the infested plant or plant parts securely for proper disposal to prevent further spread. Do not use the removed plant waste for composting or for consumption.

Chrysanthemum spray, horticultural oils and sulphur soap sprays can kill pests on contact. Use chemical controls like these sparingly as they tend to also affect other types of biodiversity.

Encourage predators to establish in your garden by keeping it pesticide-free. Ladybirds feed on the larvae of whiteflies, and can keep their population under control.