Pieris lacebug originates from Japan, it was first detected in Britain near Windsor in 1998. Since then it has become widespread in England, where it can damage the foliage of Pieris and rhododendrons. It is sometimes called the andromeda lacebug.
Latin name Stephanitis takeyai
Plants affected Pieris and rhododendron
Main symptoms Pale and mottled upper leaf; lower leaf surface has brown excrement with flattened insects and cast skins
Caused by A sap-sucking insect
What is pieris lacebug?
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 opulation has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.
- 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.
Pesticide controlThe RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
- Organic sprays, such as natural pyrethrum (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer), fatty acids (e.g. Doff Greenfly & Blackfly Killer) or plant oils (e.g. Vitax Plant Guard Pest & Disease Control, Bug Clear for Fruit and Veg) can give good control of lacebugs. These pesticides have a very short persistence and so may require reapplication to keep lacebug numbers in check. Plant oil and fatty acid products are less likely to affect larger insects such as ladybird adults
- Plant invigorators combine nutrients to stimulate plant growth with surfactants or fatty acids that have a physical mode of action against aphids (e.g. Ecofective Bug Control, RHS Bug and Mildew Control, SB Plant Invigorator and Westland Resolva Natural Power Bug & Mildew). These products contain some synthetic ingredients and so are not considered organic
- More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
- A systemic containing the active ingredient Flupyradifurone (Provanto Smart Bug Killer) is available for use on ornamentals and selected edibles
- The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) is also available
Plants in flower should not be sprayed due to the danger to bees and other pollinating insects.
Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home gardener.
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.
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