Lacebugs are sap sucking true bugs in the family Tingidae. About 20 species occur in Britain. They are named after the lace like appearance of the wings. Find out more about British species from British bugs. 

Pieris lacebug is a small (3-4mm long) with wings marked with a black and white lace-like pattern. It can be responsible for causing pale mottling most notably on the leaves of Pieris and Rhododendron. Rhododendron can also be host to the Rhododendron lacebug Stephanitis rhododendri, however since its arrival in Britain pieris lacebug has become the most frequently found. 

Look out for the following symptoms of pieris lacebug on Pieris and Rhododendron;

• The foliage develops a coarse pale mottling on the upper surface and by late summer the leaves can have a bleached whitish yellow appearance
• Heavy feeding damage may cause leaf drop on Pieris
• The underside of affected leaves is discoloured with brown excrement spots
• Adults, nymphs and cast skins may be seen on the lower leaf surface
• The adults are black insects, 3mm long, with wings that are held flat over the insect’s body. The wings are transparent with a broad black X-shaped marking
• The nymphs are wingless and have spiny blackish brown bodies

Note that rhododendrons can also be damaged by the rhododendron lacebug, Stephanitis rhododendri. This causes similar damage but is much less common than pieris lacebug and is not found on Pieris. Rhododendron lacebug has wings that are only faintly marked with a darker line across the wings near the base.

Check Pieris and rhododendrons frequently from spring onwards so action can be taken before a damaging population has developed. When choosing control options you can minimise harm to non-target animals by using the methods in the non-pesticide section below. Pesticide treatments are likely to kill natural enemies and are only likely to be successful if the entire plant can be reached. 

Non-pesticide 

• Where possible tolerate populations of pieris lacebug
• Encourage predators and other natural enemies of suckers, in the garden, such as birds, ladybirds, wasps and ground beetles

Pesticides

• Organic sprays, such as natural pyrethrum (e.g. Bug Clear Ultra 2, Neudorff Bug Free Bug and Larvae Killer) or plant oils (e.g. Vitax Plant Guard Pest & Disease Control, Bug Clear Fruit & Veg, Vitax Rose Guard) have a largely physical mode of action. These are broad spectrum so will kill a wide range of insects. Several applications of these short persistence products may be necessary to give good control. Plant oil and fatty acid products are less likely to affect larger insects
• Plant invigorators combine nutrients to stimulate plant growth with surfactants or fatty acids that have a physical mode of action against lacebugs (e.g. Ecofective Bug Control, Growing Success Bug Stop, SB Plant Invigorator and RoseClear 3 in 1 Action). These products contain some synthetic ingredients and so are not considered organic
• Further information about the use of pesticides available for management of pieris lacebug is available on the pesticides for gardeners leaflet

Download

Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Pieris lacebug overwinters as eggs that are inserted into the leaf veins but adult insects can persist on the foliage until mid-winter.

The eggs hatch in May and the nymphs initially cluster together on the underside of leaves. They later disperse and reach the adult stage by mid to late summer.

Rhododendron lacebug has a similar lifecycle.