PEST
 
   NAME
     Red Scale (California red scale)
     Aonidiella aurantii
 
   ORDER
     Hemiptera
 
   FAMILY
     Diapididea

Description of the Pest
Red scale is a hard or armoured scale, with piercing and sucking mouth parts. The adult female has a circular, red to orange/pink conical scale appearance, approximately 2mm in diameter. The male is narrower, grey and relatively inconspicuous. On maturity, it emerges winged from beneath the scale covering. Red scale does not produce the honeydew. 

Appearance of the Pest
All parts of the plant above the soil may be attacked. Red scale tends to favour well-lit positions in the canopy of trees. Saplings in open positions may be heavily infested.

Period of Activity
The nymphs are active for most of the year, in warm climates.

Susceptible Plants
Susceptible plants include citrus, wattles, willows, holly, and many ornamentals, such as roses and camellias. Small trees and saplings that are heavily infested may be seriously damaged or die.

Aucuba species are attacked by the Yellow Scale (Aonidiella aurantii) a yellow form of Red Scale. It damages the leaves and allows fungal leaf spots to infect the plant.

Damage Caused
Leaves become yellow and are shed prematurely. Bark on infested stems may crack and exude gum; there may be twig or stem die-back. When the infestation occurs on fruit, the fruit is small and its skin becomes pitted and cracked.

Control
Spray the entire plant with dilute white oil solution; a follow-up spray may be required after four weeks, for heavy infestations. Dead or damaged parts of the plant should be removed and destroyed. Natural predators such as parasitic wasps may reduce numbers of active nymphs; parasitic wasps are bred commercially in some areas for this purpose. It should be noted, however, that wasps will avoid dusty conditions.

Some chemical controls, such as methidathion, are available - please seek advice from your local nursery as to the suitable product for your area.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.