Dealing with the mites that target tomatoes

Minute arachnids or mites start off in patches on a tomato crop and spread rapidly. Generally found on the undersides of leaves, they cause damage by puncturing the plant cells to feed. Bill Kerr looks at three mite species.

- Bill Kerr

Mite species likely to invade your tomato lands are more prevalent in hot, dry conditions. Two common spider mites are the tomato red mite (Tetranychus evansi) and two-spotted mite (T. urticae). The former appears in various shades of red, while the latter has a large spot on each side of the abdomen when seen from above.

Spider mites generally start off in a few patches on the land and then spread rapidly. They are carried on the wind in the same way that newly hatched spiders are: with the help of a silk thread.

They are also easily spread by workers brushing against infected plants; the mites ‘catch a ride’ on clothing.

LIFE CYCLE

The life cycle is rapid: at 25°C, it is completed in just two weeks. The female lays between 50 and 250 eggs during her lifespan; the hotter the conditions, the higher the number of eggs laid.