Red scale (California red scale)

Aonidiella aurantii

The female scale insect has a circular, brownish-red cover about 1.8 millimetres in diameter. It is firmly attached to the surface when the female is moulting or reproducing. The insect itself is visible through the cover and has an oval body which becomes kidney-shaped at the last instar stage.
The male scale insect develops similarly until after the second moult when it becomes oval and darker than the female, measuring about one millimetre in diameter with an excentric cover. The adult male is a small, yellowish two-winged insect that emerges from under its elongated cover after four moults. It lives for about 6 hours and its sole purpose is to mate. It locates unmated females by detecting the pheromones they release.
Damage: Heavy infestations may cause discolouration, shoot distortion and leaf drop. The fruit may become pitted and unmarketable. The tree's bark may split and the twigs and branches may die back and this sometimes results in the death of the tree. Chemical control is difficult because the insects are protected by their hard waxy covers. They are also becoming resistant to many insecticides and indiscriminate use of pesticides has adverse effects on their natural predators.