Mealybugs

Pseudococcus virburni (Tuber mealybug), Pseudococcus longispinus (Longtailed mealybug), Planococcus citri (Citrus mealybug), Phenacoccus solenopsis (Cotton/Solenopsis mealybug), Maconellicoccus hirsutus (Pink, grape or hibiscus mealybug)

While there are native mealybugs, the above are considered sap sucking pests on a range of hosts including grapes, citrus, cotton, peanuts, mangoes, passionfruit, apples, pears and stone fruit.

Like aphids, mealy bugs can cause distorted leaves and weakened plants that are covered with shiny honeydew and often, sooty mould.

While mealy bugs can cause significant loss through sap sucking, the most significant damage relates to the secretion of honey dew which encourages the growth of sooty mould and other fungi. It is also visually undesirable, makes the fruit sticky and in some fruits, prevents the drying of fruit for dried fruit production. In grapes, mealybugs are also vectors for diseases such as leaf roll virus.

Refer to the links below for more detailed information on different mealybug species.

Description

Female mealybugs are soft bodied, segmented insects that are covered in a white powdery wax. They are 3-5 mm long, have filaments around their oval, flattened bodies and live in colonies where they feed on the sap of plants. In contrast, males are tiny winged insects with waxy tail filaments.

Mealybug nymphs look similar to adult females but are smaller and darker in colour.

The egg sacks of mealybugs, eggs, nymphs and adult mealybugs are often found under leaves and at the base of shoots. Honeydew deposits and sooty mould are often seen on the leaves, stems and fruit.

Control

Mealybugs can be controlled by encouraging mealybug predators such as ladybird beetles, predatory beetles, lacewing larvae and parasitoid wasps and by the considered use of insecticides, targeted at the juvenile life stages. However, focusing control on chemicals can be problematic for a number of reasons as their waxy coating repels sprays, spray contact can be difficult, they quickly develop resistance to pesticide groups and many pesticides affect both mealybugs and beneficial species.

Reducing ant populations, which are attracted to the honeydew and in turn protect the mealybugs, can also help reduce citrus mealybug populations.

Movento® is soft on many beneficial insects, including parasitic wasps, pirate bugs, hoverflies and lacewings. It is registered for the suppression of citrus mealybug in citrus, passionfruit, mangoes, and the control of longtailed mealybug and tuber mealybug in grapes, pome and stone fruit. It is also registered for cotton mealybug control in cotton. Movento should be applied at the onset of crawler emergence.

Confidor® 200 SC is registered for the control of citrus mealybug and longtailed mealybug in ornamental plants.

Related Pests

Tuber Mealybug

Pseudococcus viburni

Tuber mealybugs, also known as obscure mealybugs, are often confused with the more prevalent longtailed mealybugs. Tuber mealybugs are a pest in some grape growing regions of eastern Australia and parts of south west Western Australia. Found in all States and Territories, they are a significant pest of pome and stone fruit orchards and inland citrus crops.

Refer to the links below on different mealybug species.

Longtailed mealybug

Pseudococcus longispinus

Being present in many Australian grape growing regions, longtailed mealybugs are generally not a major issue, but in certain circumstances can become a significant problem for vignerons. Like scale pests, mealybug feed on the plant’s sap, excreting honeydew as a waste product. The honeydew provides a food source for ants, but also a medium for sooty mould to grow on. This sooty mould can be a contaminant in the wine production process or affect the appearance of table grapes, leading to the downgrading of fruit. Mealybugs, including longtailed mealybugs, are also found in other crops including citrus, apples, pears, peaches, nectarines, plums and apricots, where contamination and appearance issues from sooty mould can impact fruit quality.

Refer to the links below on different mealybug species.

Citrus mealybug

Planococcus citri

Citrus mealybugs are the most common and widespread of the mealybug species and as their name suggests, their main host is citrus, while other hosts include mangoes and passionfruit. Although significant economic damage is rare, they still have the potential to damage fruit.

Refer to the links below on different mealybug species.

References

Atlas of Living Australia (Viewed Oct 2019), ‘Maconellicoccus hirsutus: Grape Mealybug’, https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:37fdfac1-d197-4b5f-9ea2-cad2bef2975f

Australian Wine Research Institute (2011), ‘Viti-Notes: Pests and Diseases: Mealybugs’, https://www.awri.com.au/wp-content/uploads/mealybug.pdf

DPIRD (2018), ‘Aphids, mealybugs and scales’, https://www.agric.wa.gov.au/control-methods/aphids-mealybugs-and-scales?page=0%2C1

DPIRD (2018), ‘Mealybugs in grapevines and deciduous fruit tree crops’, https://www.agric.wa.gov.au/minor-fruits/mealybugs-grapevines-and-deciduous-fruit-tree-crops

Queensland Government (2018), ‘Mealybug’, Business Queensland, https://www.daf.qld.gov.au/business-priorities/agriculture/plants/fruit-vegetable/insect-pests/citrus-mealybug

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

Queensland Government (2013), ‘Solenopsis mealybug in Australia – an overview’, Department of Agriculture, Fisheries & Forestry, https://www.daf.qld.gov.au/__data/assets/pdf_file/0010/135397/SolenopsisOverview.pdf

SARDI (2016), ‘Fact Sheet: Identifying Mealybugs on Inland Australian Citrus’, https://www.pir.sa.gov.au/__data/assets/pdf_file/0007/285532/Identifying_Mealybugs_on_Inland_Australian_Citrus_Fact_Sheet.pdf