Scale insects

There are many different species of scale insects that attack cultivated plants. These sap-sucking insect pests can weaken the growth of a wide range of plants. Many species excrete a sticky, sugary substance, called honeydew, on the leaves and stems on which they are feeding. Some species also produce white, waxy egg masses on stems and the undersides of leaves.

A wide range of ornamental plants, fruit trees and bushes grown out of doors can be attacked. Several species of scale insects are confined to houseplants or those growing in greenhouses or other sheltered places.

Symptoms
Scales or shell-like bumps on plant stems and the underside of leaves. These are the outer coverings of scale insect
Heavy infestations may result in poor growth
Some species of scale insect excrete honeydew, which accumulates on the upper leaf surfaces. Under damp conditions this can be colonised by a black non-parasitic fungus known as sooty mould
Some scale insects deposit their eggs under a covering of white waxy fibres in early summer