PEST
 
   NAME
     White Louse Scale
     Unaspis citri
 
   ORDER
     Hemiptera
 
   FAMILY
     Diaspididae

Description of the Pest
Males are white, 1mm long; females are brown, to 2mm. They are initially inconspicuous, becoming more readily apparent as the infestation increases. They appear on the trunks and main limbs of citrus, gradually spreading to the twigs, foliage and fruit. The scale appears as a white, powdery surface on the plant. Nymphs or “crawlers” are red and inconspicuous.

Appearance and Distribution of the Pest
The scale is distributed world-wide.

Life Cycle
This insect has a Hemimetabolous life cycle, ie. When the immature nymphs resemble the adults.
Females produce up to 80 eggs throughout the year. 

Period of Activity
Most active from late spring through late Autumn, especially during dry, humid periods.

Damage Caused
Louse scale infestations will weaken the plant, making it susceptible to dieback and infestation by other pests. Leaves may yellow and fall prematurely.

Susceptible Plants
Citrus species and cultivars.

Cultural Control
No effective cultural controls are known.

Biological Control
Natural predators, including parasites and fungi. The presence of a predatory caterpillar is indicated by a fine, white webbing covering the surface of infested areas.

Chemical Control
Lime sulphur may be applied during winter, in alternate years.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.