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Lacebugs are sap

Sap is a fluid that circulates through a plant's vascular system, in a similar way to blood moving through our veins. Phloem sap carries the sugars produced in the leaves by photosynthesis down to roots and other storage organs, as well as carrying minerals and hormones. Xylem sap is watery and transports nutrients absorbed by the roots upwards to the rest of the plant. Some plants leak sap from wounds or pruning cuts, and this is known as bleeding. 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 .

Pieris lacebug is a small (3-4 mm long) insect, its wings are 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 Stephanitisrhododendri, 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, 3 mm 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.

• 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

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.