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.

Description

Grapevine scale can be difficult to distinguish from the other common scale of vineyards, frosted scale. While both types of scale are dark brown, grapevine scale are often slightly larger and oblong in shape while frosted scale is more rounded and has a powdery wax appearance.

Scale infestations are often patchy across a vineyard and as they are found on the stems and underside of leaves, sprayers should be set up to ensure good coverage.

Control

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

While vines should be monitored for scale throughout the growing season, monitoring underneath the bark on spurs, canes and cordons whilst vines are dormant can be an indicator of population density. If scale is detected, these areas should be tagged for further monitoring and possible treatment. A number of beneficial insects will prey on grapevines scale including parasitic wasps which can attack mature scale.

Movento® is soft on many beneficial insects, including parasitic wasps, pirate bugs, hoverflies and lacewings. It is registered for the suppression of grapevine scale in grapes.

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.

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

Buchan, G (2008), ‘AgNote: Soft Scales (Coccidae) on Grapevines in Australia’, Department of Environment and Primary Industries, http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/grapevines/soft-scales-coccidae-on-grapevines-in-australia

The Australian Wine Research Institute (2018), ‘Fact Sheet Viticulture: Scale – insect pests of vineyards’, https://www.awri.com.au/wp-content/uploads/2018/06/scale-insect-pests-of-vineyards-fact-sheet.pdf

Wine Australia (2019), ‘Grapevine scale and sooty mould’, https://www.wineaustralia.com/growing-making/pest-and-disease-management/grapevine-scale-and-sooty-mould