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California Red Scale

Aonidiella auranti

California Red Scale, Red Scale, Scale Bug

Aonidiella aurantii

by VictorCegarra. CC BY-SA 4.0

A close up of Aonidiella aurantii Red Scale on a plant
Aonidiella aurantti or Red Scale are an insect pest found commonly on Citrus species. The females are brownish-red in colour and oval in shape. When moulting, they become more kidney-shaped. The males are similar until they get to the second moult. They then become darker than the females and are yellow in colour.
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Suck sap out of plants. Can cause discolouration, leaves to drop and shoots to be distorted.


Discoloured leaves or fruit is a sign that you may have red scale insects. Leaves dropping off and shoots being distorted. Tree bark can also split and the branches can die back which can cause the whole tree to die.












Biological treatment

Cut back branches that have the insects on and destroy them to stop it from spreading any further. Ants can cause an increase of scale insects as they spread them further around, so if you notice ants around your plant it is a good start to try to control ant populations.

Chemical treatment

As they have a hard waxy cover they are difficult to kill with pesticides. They are also becoming resistant to insecticides so it is very difficult to get rid of them through chemical use.


Citrus plants


Citrus spp.

Persian Lime

Citrus × latifolia

Lemon Tree

Citrus x limon

A group of Citrus japonica oranges with green leaves


Citrus japonica

A green Citrus australasica fruit on a tree branch

Australian Finger Lime

Citrus australasica

A close up of a yellow Pomelo fruit hanging from a Citrus maxima branch


Citrus maxima

A close up of some yellow fruits hanging from a branch of a Citrus medica plant


Citrus medica

A close up of some Pinguicula moranensis with a pink flower


Pinguicula moranensis

Sweet Orange

Citrus sinensis 'Washington Navel'

Lemon 'Eureka'

Citrus limon 'Eureka'

Makrut Lime

Citrus hystrix

A Citrus deliciosa tree with green leaves

Willowleaf Mandarin

Citrus deliciosa

Some yellow Citrus junos fruits hanging from a branch


Citrus junos

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