Cabbage whitefly

Cabbage Whitefly (Aleyrodes proletella) typically feed on brassicas (mainly Brussels sprouts and kale).

Identifying Features
White-winged insects, 1.5mm long, fly up in clouds from the underside of brassica leaves when disturbed. Flat, oval, whitish-green scale-like nymphs are attached to the lower leaf surface. Black or greenish-grey sooty moulds can develop on the upper leaf surface on the sticky honeydew excreted by this pest.

Treatment
It is difficult to treat most brassica as their leaves are waxy and sprays do not stick. However; Whitefly do not do any real damage to the plants with the exception of young kale. Edible parts of cabbage, Brussels sprouts and cauliflower are not seriously affected. If whitefly is a problem, use deltamethrin or lambda cyhalothrin.

Prevention
Netting your brassica with a fine mesh will stop these pests gaining access to your plants and is advisable to stop more destructive pests such as Cabbage White butterflies.