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COCCOIDAE Soft Scale Insects

Image: Typical Cryptes baccatus colony

Scale
Photo: Robert Whyte

Cryptes baccatus is a light bluish grey scale insect when young, turns brown with age. Forms colonies of 30-40 on some Acacias including A. melanoxylon. Tended by ants, who take away the sugary exudate.

The insects live within these convex, protective "shells".

Scale insects constitute a very large group of unusual plant feeding insects. This group is commonly divided into soft scales and armored scales.

(Wingless and legless) adult scales spend their lives under protective shells. Soft scale insects have a waxy film secreted over their body wall. Armored scales are protected beneath a separate cover secreted over their bodies.

Image: Closeup of Cryptes baccatus and tending ants


Scale
Photo: Robert Whyte

Some caterpillars ( e.g. Stathmopoda melanochroa) feed on various species of Scale Insect (COCCIDAE).

Female scale insects lay their eggs under their bodies or scale covers. When they first hatch, young scales have legs and are quite active. At this stage, they are called crawlers. Crawlers disperse, locate new feeding sites, and then transform into immobile adults.

Image: Older Cryptes baccatus, turning brown


Scale
Photo: Robert Whyte

Of the scale insects considered to be pests, Citrus Red Scale is probably the most economically important. Large infestations of Citrus Red Scale can result in weakening of citrus trees, with resulting loss in yield. In particularly bad cases, the trees can die.

Image: Leaf of host plant with Cryptes baccatus


Scale
Photo: Robert Whyte

Scale insects vary dramatically in their appearance. Some are very small organisms (1-2mm) occuring under wax covers, others are shiny pearl-like objects (about 5mm). They spend most or all of their lives feeding on plants and are primarily known as plant pests in greenhouses, backyards and on fruit trees.

Ceroplastes rubens Pink Wax Scale


Ink wax scale
Photo: Robert Whyte

These little insects common in Brisbane live under a pink, waxy secretion on broadleaved plants, from which they suck juices. They secrete sugars, attracting ants which tend them. Some ladybirds are predators of their young.

Also known as Chinese Wax Scale, Hard Wax Scale

Ceroplastes rubens Pink Wax Scale


Scale
Photo: Robert Whyte

The waxy cover of the adult female is pinkish to red, convex, longer than wide and with two conspicuous pairs of white bands. Size: 3.5 to 4.5 mm. Nymphs are pinkish in color.

Ceroplastes rubens Pink Wax Scale


Scale
Photo: Robert Whyte

The scale has two generations a year in Queensland, crawlers of the first generation emerge from mid-September until early December, but mostly from mid-October to mid-November. Crawlers of the second generation emerge in February to late April.