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.

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
• stunting
• 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.

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.