Origin:
Uncertain, but currently it is found worldwide in citrus growing regions. It is a major pest concern in the citrus industry in California, and in other parts of the world has been found infesting almond, pear, plum, and roses.
Biology:
The life cycle differs slightly from typical scales in that the female may give birth to living young, rather than laying eggs beneath her wax shell, or may produce eggs beneath her wax covering. The crawlers emerge from the female and move about on the tree, or may be dispersed to other trees with wind, on birds, or on people working with the trees. After the first molt the second instars become sessile, forming a wax covering over themselves and remaining on that site on the plant. They may feed on stems, leaves, or fruit, and when the dark scales appear on the fruit it reduces the value of that fruit. There may be as many as 4 generations per year.
Identification:
The adult female is a very small and flattened scale, only about 1.8 mm across and beginning as an elongate shape but ending as round or kidney shaped as the adult. The wax shell is very flat and thin, with the actual insect visible beneath it.
Characteristicts Important to Control:
Heavy infestations can cause yellowing of the leaves of the tree, dieback of twigs and branches, and potentially the death of the tree. Death of the tree is more likely during periods when the tree is drought-stressed. Because of the serious economic nature of the pest agricultural agencies often are involved with its control. Many natural parasites and predators are known that help reduce populations. Dormant or summer oils may be effective in killing the scales, as well as contact insecticides applied when the first instar crawlers are present, and an IGR applied when crawlers are present also may be effective.
