In the first of an occasional series I look at pests and diseases which we gardeners battle with on a regular basis.
First Tuesday Terror is Cushion Scale.
Cushion scale is a sap-sucking insect that attacks the foliage of mainly evergreen trees and shrubs, especially camellia, skimmia, rhododendron, trachelospermum, euonymus and holly.
A coating of a black, non parasitic fungus known as sooty mould forms on the upper leaf surface, which develops during the winter and persists into the summer months. Yellow-brown, scale insects up to 3mm (1/8in) long can be seen near the veins on the undersides of the leaves. Later,
rectangular white waxy egg masses, up to 10mm (almost ½in) long and 2-3mm (1/8in) wide, are produced by the adult scales in early summer and the remains of these egg masses remain on the foliage throughout the year.
Sooty mould will slowly flake off the leaves during the summer. On small plants it can be removed by wiping the foliage with a damp cloth.