Tomato red spider mite

Tetranychus evansi

The tomato red spider mite feeds on a wide range of plants. In large groups, they can mummify plants, wrapping them up in silk webbing and feeding until the plant dies.

About the tomato red spider mite

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

Known hosts include:

  • crops (like tomatoes, potatoes, eggplants, 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.

Global distribution of tomato red spider mite

World distribution of tomato red spider mite

Why this is a problem for New Zealand

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).

This mite also makes large amounts of silk webbing that can mummify the plant. The webbing and constant feeding can kill plants.

There are native plants in the same families as the known hosts for the mite. We don't know the harm the mite could do to these species because it isn't here. And we don't want to find out.

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

Map of New Zealand showing where this pest could establish

How it could get here

The mite is most likely to arrive on whole plants and fresh produce. MPI has strict measures in place to limit the chances of pests like this making it through the border.

But we need you to be vigilant too. Whenever travelling to New Zealand, always declare any food or plant material in your luggage. If you fail to do so, you could face a $400 fine.

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. 

light brown mite with striking white broken bands running across its body
Tomato red spider mite
Image: Creative Commons Wikimedia

If you think you've found this mite


Note: This information is a summary of this pest's global distribution and potential impacts to New Zealand.

 

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