By Bill Woods and David Yeates, Entomologists, Entomology Branch, South Perth Pink wax scale, white wax scale and Chinese wax scale are pests of citrus. They are called wax scales because they exude a waxy covering which protects them from desiccation and from predators. Both pink and white wax scales have been in Western Australia for many years, whilst Chinese wax scale is a recent introduction and so far has only been found at Harvey. Pink wax scale on ivy leaf.
Scale insects Scale insects are sap suckers like aphids.
They insert a needlelike sucking tube into the plant and draw out the sap. After the sap has been used by the insect, it is excreted as honeydew. A black fungus known as sooty mould often develops on this honeydew. This reduces photosynthesis and discolours the fruit. The life cycle of these three scale insects is similar.