Check plants for:

• Small white-winged insects, about 1mm long, living on the underside of younger leaves in mid-summer
• In winter, the insect is present as the overwintering scale (nymph) stage. These are black, oval, scale-like objects that are 1mm long and encrusted with a white waxy powder
• Usually host plant health is unaffected. Occasionally large populations develop which can lead to sooty mould on the upper leaf surface where the insect’s sugary honeydew excrement has accumulated

This insect can usually be accepted as part of the biodiversity that viburnum and Arbustus support, it rarely affects the health of its hosts.  

Check Viburnum tinus and Arbutus frequently from early summer onwards so if necessary action can be taken before a damaging infestation has developed. 

• This whitefly rarely affects the growth or vigour of host plants and so it can be accepted as part of the biodiversity these plants support
• Encourage predators and other natural enemies of whitefly, in the garden, such as birds, ladybirds, wasps and ground beetles

Viburnum whitefly has one generation a year.

The adults emerge in mid-summer, when they deposit eggs on the underside of leaves near the shoot tips. These hatch into flat, oval whitish-green nymphs (sometimes called larvae) that suck sap from the lower leaf surface.

By autumn, the nymphs have reached the pupal stage, which is black and encrusted with a white waxy powder. Both adults and nymphs produce a sugary excrement, called honeydew, which makes the foliage sticky and can allow the growth of sooty moulds.