Spider mites

Spider mites overview

Spider mites are a group of over 1,000 species of plant feeding mites belonging to the family Tetranychidae. Adult mites are less than 1mm in size and vary in colour depending on the species and their food source. They have very small spherical eggs and they produce silk webbing that may help to protect the colony from predators or can be used to enable wind dispersal.

Spider mites are major pests in a wide range of indoor and outdoor fruit, vegetable and ornamental crops worldwide. Significant pest species include:

  • Two-spotted spider mite Tetranychus urticae
  • Bean red spider mite Tetranychus ludeni
  • Carmine mite Tetranychus cinnabarinus

Spider mites colonise the underside of leaves, where they puncture plant cells to feed on the contents. Feeding damage first appears as white or yellow speckles (stippling) visible on the upper surface of the leaf. Extreme feeding damage causes leaves to lose all their colour and dry up. Heavily infested plants can become completely covered with the fine silken webbing produced by the mites.

Spider mites thrive under hot and dry conditions and populations can increase very rapidly in the absence of suitable biological, cultural and or chemical controls. Their short life cycle and high reproductive rate have enabled them to rapidly develop resistance to miticide products.

Biological control of spider mites

Spider mites have several biological control agents including lacewings, tiny mite feeding ladybirds (Stethorus spp.), predatory gall-midges (Feltiella spp.) and a variety of predatory mites (including Phytoseiulus persimilis and Neoseiulus californicus).

It is possible to achieve excellent results using predators to control spider mites. Sustainable control is best achieved using a combination of biological and cultural controls. Cultural practices such as increasing humidity in the crop microclimate during extremely hot or dry periods can favour predators and disadvantage the pest.

Spider mite chemical control considerations

If chemical support is necessary, choose selective products that will cause minimal disruption to predatory mites and other biocontrol agents. Use the Biobest Side Effects App to access information about the effects of pesticides on biocontrol agents.

Solutions

Bright red spider mite on green leaf, close-up image.
Red mite on green leaf with two small spherical eggs visible.

Persimilis

Persimilis are predatory mites that feeds on all stages of two spotted mite and other spider mites. They provide excellent control of these pests in a wide range of field and protected crops and are among the most widely used biocontrol agents globally.  Persimilis are highly specialised and efficient predators – they consume more spider mites per day than other predatory mite species, but they cannot survive on pollen or other prey.

Adult californicus (centre) with two-spotted spider mite.
(Photo: Andrew Manners, QDAFF)

Californicus

Californicus is an aggressive and robust spider mite predator. It is tolerant of a wide range of temperature and humidity conditions and is used widely in Australia and overseas as a powerful biological control agent. Californicus is able to survive well even at low prey densities due to their ability to use alternative prey and pollen as a food source.

Slow-release sachets

Californicus slow-release sachets are a great tool to combat spider mites in protected cropping. These sachets provide an in-crop breeding system for continuous release of predatory mites over a period of several weeks. This innovative release technology reduces the need for multiple applications and helps achieve even distribution and sustained activity of predatory mites.

Disclaimer:

While we make every effort to supply you with beneficial insects and mites to help improve your pest management, and to reduce the need for pesticides, we cannot guarantee the outcome in every situation.  Our biocontrol agents do feed readily on the species that we have specified in our tech sheets and on our website.  However, there are many variables including accurate pest identification, plant species, pest density, numbers of beneficials released, environmental conditions and history of pesticide usage that influence the outcomes.  We will always do our best to help you achieve a positive outcome but we simply cannot guarantee that your problem will be solved to your satisfaction.  Because every situation is unique we are constantly learning about how best to use our good bugs.  We appreciate any feedback from your experience.

The entomology team, Bugs for Bugs.