Tomato red spider mite

Tetranychus evansi

Two small populations of the tomato red spider mite were found in Auckland in May 2020. Find out about the mite and what's being done.

About tomato red spider mites

The tomato red spider mite feeds on a wide range of plants in the Solanaceae family. In large groups, they can mummify plants, wrapping them up in silk webbing. They will feed on the plant until it dies.

This mite got its name because it eats tomato plants and is red. It makes silk webbing to protect itself and its eggs like some spiders do. But the mite doesn't just feed on tomatoes.

Find out what else the mites eat

The mite multiplies quickly and can be difficult to control. Many mite species can quickly become resistant to pesticides, which poses challenges for controlling this pest.

The detection of the mites in Auckland

In late May 2020, a small population of tomato red spider mites was found through routine surveillance at a location near Auckland International Airport. Subsequently, a further population was found in Pakuranga in South Auckland. The 2 locations are about 20 kilometres apart.

Risk of the mites to New Zealand

Biosecurity New Zealand is working with the horticulture industry on assessing the risk this discovery poses. We're also working on potential next steps.

MPI’s trade and market access specialists have assessed the discovery as unlikely to have any significant impact on trade in horticultural products. The mite is a quarantine pest for Korea, Thailand, and Ecuador. New Zealand does not export substantial host plant products to these countries.

However, we do export some host commodities to Thailand, including tomatoes and strawberries.

How did the mites get to Auckland?

It is not known how long this pest has been here, or how it arrived. It may have been carried by wind or arrived on a visitor’s clothing or bags. Or it may have hitchhiked on imported products.

Other plants the mites eat

The tomato red spider mite doesn't just feed on tomatoes.

Other known hosts include:

  • potatoes, kumara, eggplants, and beans
  • ornamental plants (roses and orchids)
  • weeds (shepherd's purse, cleavers, and fat hen).

When they start running out of food, the mites gather at the top of a plant and make small balls of silk, containing many mites and eggs. These balls can drift some distance on light winds. The balls can also stick to animals and people.

How the mite feeds

The mite has sharp mouth-parts that pierce the plant's tissues, letting the mite suck out the cell contents. It's thought to inject toxins that affect plant growth. The damage done by the mite weakens the plant, causing it to lose its leaves and dry out (desiccate).

How to identify the tomato red spider mite

There are a few red mite species in New Zealand already. Identification requires an expert (acarologist). Lots of webbing is the most obvious sign that the tomato red spider mite is present.

Pictures of the mite, its webbing, and the damage they cause

 

On the left is a red tomato spider mite web and on the right, a dessicated tomato plant.

 

A tomato turned brown by the tomato red spider mites feeding on it. A closeup of several tomato red spider mites.
Image source: Alain Migeon and Franck Dorkeld (2019) Spider Mites Web: a comprehensive database for the Tetranychidae. Available from http://www.montpellier.inra.fr/CBGP/spmweb (Accessed 05/07/2019)

Find out more

Tomato red spider mite fact sheet – Primary Industries and Regions South Australia  [PDF, 397KB]

Tomato red spider mite – New South Wales Department of Primary Industries

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