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.

Description

Female SBS are oval and flat, 3-4 mm in length and yellow-green with dark brown speckles which darken with age. Males are not present and as a result SBS reproduce without mating. Eggs are laid under the scale and emerge as crawlers usually in early spring. The crawlers move to find food and once they begin feeding they become sedentary. The crawlers undergo several moults before becoming adults.

SBS are most likely to be observed in late summer and autumn as numbers build where they inhabit twigs and leaves. Feeding and the honeydew excreted by SBS acts as a substrate for black sooty mould which blemishes the leaves and fruit and reduces photosynthesis. Ants are attracted to the honeydew, which in return protect the scale by feeding on natural enemies of SBS.

Control

The presence of honeydew or black sooty mould is often the first sign of an SBS infestation. An application with spraying oil when crawlers are abundant can help control SBS. Foliar insecticide applications should be made prior to significant build-up of sooty mould as this will impact their efficacy so apply early in the spring for best results. Beneficial insects, including parasitoid wasps, ladybird beetles (larvae and adults), lacewing larvae, mites and some caterpillars can also help control SBS. Some fungi can also attack SBS. Ants which feed on the beneficial insects should be controlled.

Movento® 240 SC Insecticide is compatible with an integrated pest management (IPM) system. Movento is considered soft on many beneficial species, including parasitic wasps when used as directed, and is registered for foliar application for the control of SBS in citrus.

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.

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.

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.

San Jose Scale

Soft brown scale

Coccus hesperidum

References

Department of Agriculture and Fisheries (2017), ‘Soft Brown Scale’, https://www.daf.qld.gov.au/business-priorities/agriculture/plants/fruit-vegetable/insect-pests/soft-brown-scale

Department of Primary Industries NSW (Viewed Oct 2019), ‘Growing lemons in Australia – a production manual’, Soft Scales pg 5-7, https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/137723/11-lemon-pests.pdf

Koppert Biological Systems (Viewed Oct 2019), ‘Brown soft scale’, https://www.koppert.co.uk/challenges/mealybugs-and-scales/brown-soft-scale/

Moore, S (2012), ‘Soft Scales’, Citrus Research International, Production Guidelines Vol III Chapter 3: Specific Pests, Part 11.5 pg 1 – 3, https://www.citrusres.com/system/files/documents/production-guidelines/Ch%203-11-5%20Soft%20scales%20-%20Feb%202012.pdf

Soft brown scale

Description

Control

Related Product

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)

Grapevine scale

Parthenolecanium persicae

Pink wax scale

Ceroplastes rubens

Red scale

Aonidiella aurantii

San Jose Scale

Soft brown scale

Coccus hesperidum

References

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