Pink wax scale

Ceroplastes rubens

A type of soft scale, pink wax scale is commonly found on the upper surface of leaves along the midrib in crops including citrus, mangos, avocados and custard apples. While frequently found in orchards, pink wax scale generally causes minor damage.

Refer to links below for more information on different scale species.

Description

After hatching, crawlers spread to different parts of the plant where they settle, insert their proboscis into the plant and begin feeding on sap. The young scale develop a white waxy appearance which transitions into a hard pink to red wax cover as the scale matures. Adults are about 3-4 mm long with a smooth globular shaped body with flattened edges with two lobes on each side and a depression at the top. They are sedentary, laying eggs under their body, which then hatch to start the cycle again.

Whilst feeding on the plant’s sap, scales excrete honeydew which provides a medium for the growth of sooty mould. The sooty mould reduces the leaf photosynthetic area and reduces the visual appeal and marketability of fruit.

Control

Scale can be difficult to detect at low densities, however the presence of ants and sooty mould are good indicators they are present.

For best control, apply insecticides when all of the crawlers have hatched, ensuring good application coverage.

Pink wax scale has a number of natural predators including parasitic wasps, ladybird beetles and lace wings. Movento is soft on many beneficial insects, including parasitic wasps, pirate bugs, hoverflies and lacewings. It is registered for the control of pink wax scale in citrus and mangos. Confidor 200 is registered for the control of soft scales in ornamental plants.

Related Pests

Scale

Parthenolecanium persicae (Grapevine scale), Lepiddosaphes beckii - (Mussel scale), Ceroplastes rubens (Pink wax scale), Aonidiella aurantia - (Red scale), Quadraspidiotus perniciosus - (San Jose scale), Coccus hesperidum - (Soft brown scale)

There are more than 20 families of scale including hard (armoured) scale, soft scale, mealybugs and felt scales. Whilst all scale insects are sap sucking, a large amount of diversity exists between species. Soft scales do not have a separate protective cover, in contrast the protective cover in hard scales is not attached to the soft insect body. They infest a large group of host plants including citrus, mangoes, passionfruit, pome fruit, stone fruit, ornamentals and grapes. The term scale refers to the coating over the back of the insect.

Refer to links below for more information on different scale species.

Grapevine scale

Parthenolecanium persicae

Grapevine scale is an increasing problem for Australian grape producers where, in high numbers, they can reduce the vigour of grapevines. These soft scale feed on sap secreting honeydew which in addition to attracting ants, commonly leads to the development of sooty mould. This mould can form on all parts of the vine, including the fruit, and can lead to the grapes being downgraded or rejected by the market.

Refer to links below for more information on different scale species.

Red scale

Aonidiella aurantii

Belonging to the armoured scale group, red scale, also known as citrus red scale or Californian scale, is the most common and damaging scale affecting citrus in Australia. It occurs on a wide range of hosts including citrus, passionfruit, carob, roses, papaya and olives.

Refer to links below for more information on different scale species.

Soft brown scale

Coccus hesperidum

Soft brown scale (SBS), also commonly known as brown soft scale, is common in tropical and sub-tropical citrus growing areas of Australia. It infests many hosts including citrus, papaya and ornamental plants. SBS belong to the soft scale group, unlike hard scale species, they do not have a separate scale cover. SBS are known for producing large amounts of honeydew and subsequently are commonly accompanied by sooty mould and ants.

Refer to links below for more information on different scale species.

References

Broughton, S (2007), ‘Farmnote: Scale in citrus’, Department of Agriculture and Food (DPIRD), https://citrusaustralia.com.au/wp-content/uploads/fn2007_citrusscale_sbroughton.pdf

Department of Agriculture and Fisheries (2017), ‘Pink wax scale’, Queensland Government, https://www.daf.qld.gov.au/business-priorities/agriculture/plants/fruit-vegetable/insect-pests/pink-wax-scale

Hardy, S (2004), ‘Growing Lemons in Australia – a production manual’, Citrus Australia, https://citrusaustralia.com.au/wp-content/uploads/lemon_growing_manual_11_Pests.pdf

Manners, A (2016), ‘Scale insects: A difficult problem that can be managed’, Agriscience Queensland, Department of Agriculture and Fisheries, https://www.horticulture.com.au/globalassets/hort-innovation/resource-assets/ny15002-scale-insects-pest-mgmt-plan.pdf