September Pest of the Month - Flat Mites

25 September 2023

Flat mites, also known as false spider mites, can cause significant damage to plants.

Flat mites are closely related to spider mites and feed in a similar way. Flat mite damage can vary substantially between species and plant parts.

Flat mites can:

• feed on leaves causing:
  • chlorotic stippling (similar to spider mite damage)
  • brownish discolouration or russeting on the undersides of leaves that is often along the midrib
  • leaf cupping
  • reduced leaf size
  • leaf death
• cause damage similar to broad mites and thrips, including:
  • slight to severe leaf deformation
  • twisted new growth
  • corky lesions on stems, leaves, flowers and fruit.

Some species of flat mites inject saliva into the plant which may increase the amount of damage to the host beyond the removal of cell contents. Flat mites may also be present under the leaf sheathes of grasses and grass-like plants, causing necrotic lesions along leaves, which may reduce growth and increase the likelihood of secondary infection.

Most species cannot be seen without a hand lens and very small species may require a microscope. Most pest species found in Australian production nurseries come from the genus Brevipalpus and tend to be flat and red.

A small number of species are known to transmit viruses, e.g. Orchid fleck virus and Citrus leprosis virus (the latter is not in Australia). Some species in this group are a significant biosecurity threat, e.g. red palm mite.

For more information on flat mite biology and management, download our factsheet.