Mites

• Mites can be difficult to see without a hand lens.
• They have oval-shaped bodies and 8 legs.
• Their colour varies with species.
• Their size varies from less than 0.5mm to about 1.5mm.

Predatory mites (which have teardrop-shaped bodies and tend to move relatively quickly)

• Mites are widespread across Australia and are favoured by hot, dry conditions.
• RLEM is less of a pest in Queensland than in southern states.
• Spider mites tend to become abundant during warm, dry conditions. They may also be an end-of-season pest, flaring when pesticide applications targeting other pests kill off predators that are keeping the mite populations in check.
• Spider mites are the most common pest mite. They all produce silk, though some more than others. High infestations of some species can lead to plants being completely covered in silk.

Most mites will attack a range of host species; some are specific to either grasses or broadleaf hosts. Some species of mites may feed on only 1 or a small number of host plants.

• Adults and nymphs pierce and suck leaf cells, causing mottling and discolouration of leaves.
• Damage to growing tips can lead to deformed growth.
• Heavy infestations can result in leaf drop, yield loss, and even plant death.

• Eggs hatch into 6-legged larvae and usually develop through 3 nymphal stages.
• Development from egg to adult can be very quick (7 days for two-spotted mite), allowing populations to build rapidly.

Mites can be difficult to see without a hand lens.

• For mites that attack seedling crops, check from planting to early vegetative stages.
• For spider mites, check the underside of older leaves using a hand lens. Monitor leaves that have tiny chlorotic spots (stippling), chlorosis or unusual growth.

Predators include small predatory bugs, thrips, lacewings and ladybirds.

Predatory mites are available for inundative release and can be very effective in many situations.

• Monitor crops regularly, more frequently during high-risk periods and for high-risk crops.
• Remember that management in broadacre crops differs from that in vegetables, fruit and other horticultural crops.
• Control alternative host plants (weeds and volunteers) between seasons.
• Many species have developed insecticide resistance, so do not solely rely on pesticides to manage mites. RLEM have developed resistance to synthetic pyrethroids in some regions.
• CSIRO have developed a model (TIMERITE) to predict the best spray date in spring to control RLEM the following autumn.
• Grazing may help reduce pasture mite populations.
• Regular irrigation reduces the risk of peanut mite damage.