Body - Up to 10mm. Oval. Soft. Under a domed covering.
Wings - 1 Pair in males, none in females. Wing-span 1mm
Mouthparts - Stylet. Sucking. Near rear of head.
Antennae - Very small or absent. 3-10 segments.
Eyes - 2 Compound.
Legs -Very small or absent. Feet (Tarsi) have 4 segments.
Head - fused to thorax.
Thorax - 3 segments.
Abdomen - Eight pairs of spiracles on underside. Segments ill defined
Egg - ovoid.
Habits - Males fly but don't feed. First instar mobile. Female sedentary and protects eggs. Some species may not produce males and females can produce eggs directly.
Usually 5 stages (instars). Look quite different to the adults.
Eggs laid under or stay within the females body then hatch to produce nymphs. First instar nymph is highly mobile. Later instars less so. Mature female sedentary and attaches herself to the plant by her mouthparts (stylet) and forms a waxy, leathery or cottony covering over her soft body. Tend to live in colonies. May be tended by ants who feed on the honey dew and protect them from predation.
Origin and History:
Sooty moulds growing on the honey dew excreted by scales may make fruit unsaleable. This is usually the greatest cause of economic loss. Ceroplastes destructor is a pest of citrus. Ceroplastes rubens, Coccus hesperidum, Parasaissetia nigra and Saissetia coffeae are pest of many fruit species. Pulvinaria elongata and Symonicoccus attack sugar cane and other grasses. Other species damage cut flowers and vegetables. Some have toxic saliva which may kill plant tissue and cause distortions.
Management and Control:
White oil, soap solutions and insecticides are used on heavy infestations.
Aphids, Lerps, various 'bugs' leafhoppers and scales. Cochineal and shellac are made from scale insects.
CSIRO. The Insects of Australia. Melbourne University Press. (1991) p60, 182, 443, 458, 461-464, 769, 967, 968, 987.
Goode, J. Insects of Australia. Angus and Robertson. p61.
Jones, D. & Elliot, R. Pests Diseases and Ailments of Plants. Lothian Publishing Australian Co. p71-73.
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