Red Scale

Common name

California red scale

Scientific name

Aonidiella aurantia

Nature of damage

Red scale will go unnoticed at low infestation levels. At high infestation levels red scale will cause speckling of fruit, discoloration, leaf drop, deformed shoots and severe damage to fruit bearing shoots. In severe instances fruit might be damaged to the point where it is not marketable. Red scale has been recorded attacking more than 200 plant species some of which are citrus, bananas, papayas, guavas, olives, potato tubers, ornamental plants and cycads.

Identification

Red scale, a Hemipteran sap sucking insect, gets its name from the reddish-brown scale cover it produces for protection. The scale increases in size as the insect grows and reaches a maximum size of approximately 1.8mm in diameter for a full-grown female. Males and females are visually dimorphic during development; females have a round scale covering them and males have an elongated scale under which they grow.

Biology

Male red scale will emerge from their scale as winged adults once they have completed their nymphal stages. The males will then mate and die within a few hours after emerging from their scales. Females will live longer and give live birth to around 100 crawlers. The crawlers are then dispersed by wind, birds, mammals or farm workers picking fruit. The crawlers will find a suitable spot and settle there, inserting its mouth part into the plant and starting to feed. A female red scale will take anything from 55 to 138 days to complete its life cycle, depending on environmental factors, while males will only take between 26 and 79 days to complete their life cycle.