Scale insects are sedentary sap sucking insects. Eggs are produced and incubated under the cover of the waxy scale or layers of shed skin from previous life stages. Nymphs can crawl a short distance before attaching themselves to the plant to start the feeding process. Most scale insects are very small (1-4.5 mm) and colours range from white to reddish or dark brown.
Scale insects are important pests of ornamental, citrus and fruit trees, roses, aloes and other shrubs. Some species excrete honeydew causing sooty moulds to cover the plant surfaces. These insects can reduce the vigour of plants and major damage is caused due to downgrading of citrus fruit as result of the cosmetic injury.