Southern red mite

Alert

Have you seen Southern red mite?

Be on the lookout and report signs to Biosecurity Queensland on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

Early detection and reporting are key elements in controlling Southern red mite.

The tiny southern red mite is a pest of broad leaved woody plants overseas. While it can feed on a wide range of plants, it can have a more serious impact on azaleas and camellias. Heavy, unmanaged populations of the mites can cause poor plant growth and eventually kill plants.

Cause

Southern red mite (Oligonychus ilicis) is a spider mite. They are tiny arthropods or spider-like creatures.

Other names

  • Coffee red mite
  • Plane tree spider mite

Description

Adult

  • Spider-like.
  • About 0.7mm in length, barely visible with the naked eye.
  • Roundish body with 4 pairs of legs.
  • Deep purplish red to reddish brown in colour with a pale patch in the centre of the back and lighter coloured legs.
  • More translucent near the head.
  • Males are generally smaller than the females.

Larvae

  • Tiny, orange coloured.
  • Resemble the adults but have 3 pairs of legs.

Nymphs

  • 2 nymphal stages.
  • Very similar looking to adults with 4 pairs of legs.

Egg

  • Round, deep red and less than 0.5mm in diameter.

Plant stage and plant parts affected

Any plant growth stage can be affected, with leaves most impacted.

Plant damage

The mites usually feed on lower leaf surfaces causing stippling (pale dots) and bronzing of leaves from the damage as they suck the contents from plant cells. Leaf curling and distortion, and leaf fall can result from severe mite infestations, which lead to poor plant growth and eventually may kill plants.

May be confused with

Southern red mite can be easy to confuse with many other species of spider mites that have an orange to red colouration, including two spotted mite when it is red in appearance. However, many spider mites have a white, opaque or translucent spherical egg. Southern red mite eggs are reddish-brown.

Distribution

Found in Brazil, Italy, Japan, the Netherlands, Paraguay,  South Korea and the United States. It was found in Sydney in the late 1990s and eradicated. Southern red mite does not occur in Australia.

Hosts

Azalea, camellia (including tea) and holly are the most common hosts. Southern red mite has also been reported on a wide range of other plants including boxwood, camphor laurel, coffee, cotoneaster, eucalyptus, guava, hibiscus, loquat, oak, pear, pecan, quince, rhododendron, rose apple, silky oak, and walnut.

Life cycle

  • There are 4 life stages.
  • The mite over-winters as eggs which are attached to the lower surface of the leaves.
  • Larvae hatch from the eggs in spring.
  • After the larval stage there are 2 nymph stages during which the mites feed, grow and moult.
  • During moult, the mites shed their exoskeleton, which is whitish in colour.
  • After the final moult, the adult emerges.
  • Most active during spring and autumn.

Impacts

Australia's valuable nursery industry is highly diverse, propagating plants for ornamental retail, landscape, forestry, revegetation and commercial fruit and vegetable production. The annual production value combined is over $15 billion (Source: Plant Health Australia).

Southern red mite can damage leaves. Leaf distortion and leaf fall can result from severe mite infestations, which leads to poor plant growth and eventually kill plants.

Backyard gardeners would also be affected.

How it is spread

There are no specific reports on how southern red mites are dispersed. However, long distance spread is likely by people moving infested plant material. The mites are also likely to be hitchhikers and could be carried on infested equipment and clothing, or may be carried in the wind.

Monitoring and action

Check plants, particularly those with poor growth and leaf fall, for pale dots (stippling), bronzing and curled or deformed leaves.

Look at affected leaves closely for the white exoskeletons of mites or tiny red spider-like mites (a 10x hand lens can be useful).

If you suspect southern red spider mite, report it to Biosecurity Queensland on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

Control

Call 13 25 23 if you find a plant you suspect may be Southern red mite to seek advice on control options.

Legal requirements

There are no specific legal requirements for southern red mite.

Southern red mite is a significant pest threat for the nursery industry.

If you suspect the presence of southern red mite, report it to Biosecurity Queensland immediately on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

If you think you have found southern red mite, you must take all reasonable and practical steps under your control to minimise any associated risks. This is called a general biosecurity obligation (GBO).

Further information