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.

Description

Adult female citrus mealybugs are about 3 mm long and like other female mealybugs, are covered in a white mealy wax. They have 18 pairs of short waxy filaments around their bodies which are shorter at the head end and longer towards the rear. If squashed, their body contents are a yellow colour.

Male citrus mealybugs are short-lived insects with one pair of fragile wings and non-functional mouthparts. Mealybug nymphs look similar to adult females.

Citrus mealybug crawlers settle under the fruit calyx in late spring before moving to depressions in the fruit or between fruit where they damage the fruit surface while feeding. The symptoms of feeding damage include leaf distortion and weak, stunted plants. Honeydew produced by mealybugs can cause a heavy black soot to form on fruit, resulting in end rot and fruit drop.

Control

Citrus mealybugs can be managed by maintaining beneficial insect populations, including predatory beetles, ladybird beetles, lacewing larvae and parasitoid wasps, which when strategically released can provide reliable control. Reducing ant populations, which are attracted to the honeydew and in turn protect the mealybugs, can also help reduce citrus mealybug populations.

A timely application of spray oil targeting immature stages of the pest can provide effective control. Reliance on chemicals alone can be challenging as insecticides harm many of the beneficial insects. Citrus mealybugs are quick to develop resistance to synthetic pesticides, therefore the number of sprays should be limited.

Movento® is soft on many beneficial insects and is registered for the suppression of citrus mealybugs in citrus, mangoes and passionfruit.

Confidor® 200 SC is registered for the control of citrus mealybugs in ornamental plants.

Related Pests

Mealybug

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.

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.

References

Broughton, S (2015), ‘Mealybugs in citrus’, DPIRD https://www.agric.wa.gov.au/citrus/mealybugs-citrus

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

Bugs for Bugs (Viewed Oct 19), ‘Mealybugs’, https://bugsforbugs.com.au/whats-your-pest/mealybugs/