Mealybug
Pseudococcus spp.; Planococcus citri
Soft-bodied sap-suckers covered in white waxy fluff. Usually hide in leaf axils, under leaf sheaths and at the crown.
Background
Several mealybug species attack vegetables, herbs and fruit trees in Australian gardens. They feed by piercing tissue and sucking sap, producing large amounts of sticky honeydew. The honeydew supports black sooty mould, which itself reduces photosynthesis. Their waxy coating makes them highly resistant to many contact sprays.
How to identify
- Adult females: oval, 2-5mm, coated in white mealy wax, often with fine waxy threads at the tail
- Eggs: laid in white woolly egg sacs
- Damage: clustered colonies at leaf axils and crowns, honeydew, sooty mould, stunted growth
Life cycle
Females produce 100-500 eggs in a woolly ovisac. Crawlers hatch and disperse to new sites. 2-6 generations per year depending on climate.
Weather triggers
- Temperature: 18-32°C
- Warm conditions favour build-up. Frequent heavy rain physically knocks off crawlers.
Peak season (southern hemisphere)
Red = active season · Dark red outlined = this month
Affected vegetables & crops
Click any crop to see current prices and growing info.
Climate zones at risk
Organic & low-impact control
- Dab individual colonies with a cotton bud soaked in methylated spirits
- Horticultural oil sprays — must thoroughly coat the colony to breach the waxy coating
- Release of the mealybug destroyer (Cryptolaemus montrouzieri) ladybird
- Remove heavily infested parts
Chemical control
- Systemic options exist but are generally not needed in home vegetable gardens
- Oil sprays at correct concentration are the main tool
Always read product labels — registrations change.
Prevention
- Inspect nursery stock before planting
- Prune to maintain airflow
- Keep ants in check — they farm mealybugs for honeydew and drive off predators
Companion planting
Plants that attract lacewings and ladybirds (alyssum, cosmos, yarrow) help to suppress mealybug populations.
Biosecurity
Widespread, no quarantine issue for home gardens.
Sources
- Agriculture Victoria — Mealybugs
- NSW DPI — Mealybug management
- Sustainable Gardening Australia — Mealybug
Accuracy confidence: high. We update this library as new extension guidance is published.