Spider Mite

Latin name: Tetranychus urticae (Two-spotted spider mite) and other Tetranychidae species

Spider mites are tiny sap-sucking arachnids that attack a wide range of ornamental plants, vegetables, fruit trees, indoor plants and nursery stock throughout Australia. They thrive in hot, dry conditions and are most active during spring and summer. Spider mites feed by piercing plant cells and extracting their contents, causing leaves to become speckled, discoloured and weakened. Heavy infestations produce fine webbing that can cover leaves, stems and growing tips.

Because of their rapid reproduction, spider mite populations can increase dramatically during warm weather if left untreated.

Lifecycle

Spider mites undergo several developmental stages.

Females lay eggs on the undersides of leaves.
Eggs hatch into six-legged larvae.
Larvae develop through two nymph stages before becoming adults.
Adults reproduce rapidly, with a complete lifecycle taking as little as one to two weeks in hot weather.

Multiple overlapping generations occur throughout the growing season.

Identification

Adults measure less than 0.5 mm long.
Pale green, yellow, orange or red depending on species and season.
Two-spotted spider mites have two distinctive dark spots on their backs.
Fine webbing present on leaves and stems during heavy infestations.
Usually found on the undersides of leaves.
Tiny moving dots visible with a hand lens.

Damage

Fine yellow or white stippling on leaves.
Bronzing or silvery discolouration of foliage.
Premature leaf drop.
Reduced plant vigour and growth.
Fine webbing covering leaves and shoots.
Severe infestations can kill young or stressed plants.

SOLUTIONS

At the first signs of stippling or fine webbing: Apply AzaMax Organic Insecticide thoroughly, ensuring complete coverage of the undersides of leaves where spider mites feed.

On ornamentals, vegetables and nursery plants with active infestations: Apply Apparent Cocky to provide systemic protection against feeding mites where appropriate according to the product label.

In hot, dry conditions favouring spider mites: Monitor susceptible plants regularly, increase humidity where practical, and treat infestations early before populations expand.

Where infestations are persistent: Remove heavily infested foliage, avoid unnecessary broad-spectrum insecticide use that may harm beneficial predators, and rotate suitable control products as part of an integrated pest management program.