Pest of the month: scale insects

Over the last two years I have been taking photos of scale insects parasitising my bonsai. Only this month, I became more certain about their identities. Unlike the Brown Soft Scale I talked about last month (see http://lomov.blogspot.com.au/2013/04/pest-of-month-brown-soft-scale.html) these species secrete wax, which formes a protective shell over their body.  All four species shown below are invasive pests introduced to Australia from various parts of the world. All four have a wide range of host plants. The size of these insects changes as they grow, but the bits of plants shown in the photos should provide you with a rough size scale. Anyway, here they are.

A – The Pink Wax Scale (Ceroplastes rubens) on Japanese Flowering Quince;
B – The Nigra Scale (Parasaissetia nigra) on Japanese Black Pine;
C – The Fly Speck Scale (Gymnaspis aechmeae) on Port Jackson Fig;
D – The Hemispherical Scale (Saissetia coffeae) on Japanese Box.