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Red spider mite

Posted: Thursday 24 July 2014
by Pippa Greenwood

They say that size isn’t everything, and that's certainly true of the glasshouse red spider mite. It's extremely small and phenomenally damaging.


Red spider mite

They say that size isn’t everything, and that's certainly true of the glasshouse red spider mite. It's extremely small and phenomenally damaging.

It has a habit of sneaking up on you and catching you unawares. Well armed with piercing mouthparts, the red spider mite feeds voraciously, causing numerous tiny ‘bleached’ spots on the leaves. As the situation worsens, the points of damage become so numerous that the leaves appear pale and may brown and start to die. Meanwhile the dear little pests, sensing that their food supply is has virtually died, spin lots of tiny silken threads and form miniature ‘silken ropes’ down which they climb and so escape to pastures new – the next plant in the row.

Red spider mite is more correctly known as the two-spotted mite, but somehow this more logical name has never caught on. It's a more logical name because the red spider mite is only likely to be this colour towards the end of the year when preparing to hibernate. The rest of the time it is yellowy khaki, with two distinct dark spots on its back.

RSM, as I like to refer to them, are having a ball right now as they adore hot, dry weather. So do take the time to check plants, especially those growing in greenhouses, frames, porches, polytunnels and as houseplants for signs of attack before the problem gets too bad. Grab a magnifying glass to study the undersides of the leaves and look for the mites. They hate getting wet feet, so regular misting with water will help to deter them.

It's also a good idea to introduce some predatory mites (Phytoseiulus persimilis). They'll charge about all over the plants in search of their food – adult and young red spider mites and their eggs. You have to buy them mail order as life on a garden centre shelf would be likely to prove fatal. But if you do this as soon as you spot the early signs of an RSM infestation, and providing the environment has not already been polluted with chemicals, they'll do a great (and silent) job of sorting out the problem.





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ladyroseella 31/08/2014 at 19:25

i dont no if its the same but i have some poted lillys thy only about 5ft but thy lovely to look at and this year we have had some red like spidder things on them one iof the plants was in a right state with them we did try things like washing up stuf and bycarbinat soda it seamed do the trick and we saw one or to on them hope we dont get them next year eny iders please christina

philippa smith2 31/08/2014 at 19:36

Ladyrosella...........it is perhaps the Lilly Beetle you have rather than Red Spider Mite.

If you want to avoid a chemical solution, you could pick off the beetles as soon as you see them.

Mike Allen 31/08/2014 at 21:28

Quick check. Red Spider mites usually appear in very close groups, usually kind of huddled together. They are a waxy red colour and are about 1mm long with four pairs of legs. The Lily beetle is much larger and is a bright shiny red, with black underside. Only three pairs of legs and total length of 6-7mm. There are chemicals available to treat both. Mites can easily be rubbed out via finger and thumb. Lily beetles can be picked of easily. Mind you. They do tend to drop to the ground at the slightest threat. They are very difficult to spot when belly-up

Cangrandmafixiit 04/09/2014 at 01:11

Red spider usually a pest of dry weather and plants that have got too dry or are stressed .spray well with water it will help