Papaya mealybug
Papaya mealybug (Paracoccus marginatus) is an invasive insect pest that spreads rapidly.
It forms large infestation on leaves, fruit and stems of host plants such as papaya, frangipani and hibiscus.
It is a threat to commercial papaya production, as well as backyard trees.
There is no threat to humans posed by this pest.
Location
Papaya mealybug was first reported in July 2023 and has widely spread through Darwin, Palmerston and Howard Springs.
Appearance
Papaya mealybug can be easily mistaken for other species of insects.
Key characteristics of the papaya mealybug include:
- 2mm to 3.5mm long
- yellow body covered in white wax with a fringe of short filaments
- round yellow eggs laid inside an egg sac
- very sticky wax with lots of honeydew
- presence of sooty mould on the infested plant.
Spread
Papaya mealybug crawlers have a limited range of natural spread to neighbouring plants.
Strong winds may increase this range, as well as movement of infected plants, soils and fruits.
To prevent further spread, you should not transport infected plants unless disposing of. Follow the control measures below.
Symptoms
Heavy infestations of papaya mealybug cause a range of symptoms including:
- leaf chlorosis, deformation or crinkling
- premature aging of leaves
- flowers and fruit may be underdeveloped or may drop under sever infestation
- sooty mould formation around mealybug honeydew secretions
- thick white, sticky waxy coating on leaves, stems and fruit.
Control measures
If you suspect papaya mealybug, you don't need to remove the tree. It can be controlled by its natural enemies or supressed by pesticides.
However, if you prefer to dispose of the tree, you should:
- remove the infected parts
- place the infected parts in a sealed garbage bag
- place it in the bin for general waste disposal.
Natural enemies
Natural enemies of the papaya mealybug are the best type of control, as seen in several countries.
Its natural enemies that are present in the NT include:
- ladybird beetles and larvae
- lacewing larvae
- hover fly larvae
- specific parasitic wasps.
Pesticides
A white oil or soap pesticide can also be applied to suppress infestation without harming good bugs. They will not kill all the mealybugs and will require follow up sprays.
Even when dead, mealybugs will remain on the plant. You should scrape back some of the mealybug to see if it's still alive.
When using a pesticide, always wear protective clothing and follow the instructions on the product label. Make sure you check dosage, timing of application and pre-harvest interval.
Submit a sample
As papaya mealybug is now widely spread, reporting is no longer required.
If you wish, you can still submit a sample in a sealed bag to be tested at:
DITT Entomology
Berrimah Agricultural Laboratories
Berrimah Farm, Darwin NT
Phone: 08 8999 2258
You can also email photos to insectinfo@nt.gov.au.
More information
Read the papaya mealybug fact sheet PDF (5.8 MB).
For biosecurity alerts and updates, go to the Biosecurity NT Facebook page.
Give feedback about this page.
Share this page:
URL copied!