© J. Wessels, Queensland Government
© P. Grundy, Queensland Government
Australia has a large number of native mealybug species, including members of the genera Paracoccus, Ferrisia and Pseudococcus. Pest species in field crops include peanut mealybug and solenopsis mealybug.
- Female adults are about 3mm long.
- Female adults and nymphs are oval and covered in a white waxy coating giving them a mealy appearance.
- Males are small aphid-like winged insects.
- Peanut mealybug colonies form on shoots, stems, leaves and peanut kernels, and develop into white masses.
- Ants can nurture mealybug colonies, collecting honeydew while keeping predators away.
Distribution and habitat
Widespread; generally prefer warmer conditions.
In field crops, hosts are primarily peanut, cotton, mungbean and sunflower. Mealybugs are also found in a wide range of horticultural crops, garden plants and weed species.
Mealybugs pierce and suck on plant tissue. Damage is often worse in stressed plants. Symptoms include:
- reduced plant vigour and shortened season
- distorted shoots/leaves
- reduction in flowers/seeds/fruit
- honeydew contamination and sooty mould
- peanut kernels of infested plants may collapse and turn black
- 'hot spots' of dead plants.
- Females lay egg sacs containing hundreds of eggs.
- Young nymphs (called 'crawlers') are highly mobile.
- Only males have a pupal stage.
- Many generations can occur within a year.
- Can hibernate over winter on host plants or in soil.
Monitoring and thresholds
Can affect any plant stage but is often difficult to detect until colonies are well advanced. Often:
- infestations are close to paddock edges or in poorly drained areas
- in peanuts, colonies are found at the base of plants on the taproot and pods.
- in cotton, early infestations of solenopsis mealybug cause 'hotspots' of dead plants.
Mealybug ladybird, other ladybirds and predatory beetles, lacewing larvae, parasitoid wasps.
Practice good farm management and hygiene by:
- preventing mealybugs moving into farms and fields that are currently mealybug-free
- restricting movement of people and machinery in infested areas
- regularly washing clothing and equipment that may transmit crawlers
- keeping fields and non-crop areas free of alternative host plants.
Mealybugs are very difficult to control with chemicals as:
- their waxy coverings repel sprays
- they hide in sheltered areas of the plant
- they quickly develop resistance to pesticides groups
- most pesticides that are toxic enough to affect mealybugs will impact on beneficial populations.
- Solenopsis mealybug—The Beatsheet
- Mealybugs—Bugs for bugs
- Registered chemicals database—Australian Pesticides and Veterinary Medicines Authority (APVMA)
- Green lacewing larva eating mealybug (video)—The Beatsheet
- Solenopsis mealybug in cotton (video)—CottonInfo
- What to do if you find a mealybug hotspot (video)—CottonInfo
- Last reviewed: 19 Dec 2018
- Last updated: 19 Dec 2018