Dealing with red spider mite

Posted: Wednesday 8 August 2012
by Pippa Greenwood

Red spider mite loves warm, dry environments, so is often to be found decimating greenhouse and house plants.

Red spider mites, and silk webbing on plant foliage

When I’m keeping garden notes I always use the acronym RSM, which stands not for Regimental Sergeant Major, but Red Spider Mite. Like its military namesake, it's quite a force to be reckoned with. The faint flecking it causes on infested plant foliage soon turns to larger scale browning and drying - sometimes even death.

Red spider mite loves warm, dry environments, so is often to be found decimating greenhouse and house plants. I check for it regularly, as once established it’s well nigh impossible to eradicate.

The tiny mites are so small that a magnifying glass will come in very handy for spotting them. Look out for yellowy green mites with two dark blotches on their backs, four pairs of legs. You’ll usually see them on lower leaf surfaces, often with telltale silken webbing.

When doing battle with red spider mites, it'sorth remembering that they really don’t like damp or wet feet. I find that regular wetting of the plants, or misting of houseplants is an effective, easy way to deter them or limit population levels.

When numbers are higher, I definitely want a better level of control, so I resort to another, predatory mite called Phytoseiulus persimilis. This races around plants, seeking out and eating any red spider mites – eggs, young and adults. It works really well, and because these beneficial mites have a built-in seek-and-find mechanism, they work far better than a mere human armed with a spray.

Even if you’re happy to use pesticides, Phytoseiulus persimilis is especially good for plants you’re likely to eat, or those in a conservatory, where you might like to sit and relax without being surrounded by chemicals. It’s definitely worth a try!

Discuss this blog post

Talkback: Dealing with red spider mite
Your comment will appear after a quick registration step

Jackers 19/08/2012 at 13:16

The cucumber plants in my greenhouse were growing well but started to develop "powdery mildew" which I was told was due to the atmosphere being too moist.I tried to increase ventilation and water carefully.I now have mildew and red spider mite which I know like it hot and dry - you see my dilemma, where is the flaw in the argument? Is there a "dry loving" form of mildew ?

kaycurtis 24/08/2012 at 21:39

I only had one plant in the greenhouse and that was a small peach, unable to put the peach out because in the rain it gets peach leaf curl, anway there it was infested in no time with red spider mite, you can't win can you, it's either one thing or another. Not giving up though

Organic Mechanic 30/09/2012 at 04:37

We have found a natural spray which is NOT chemical based. Safe for use with your plants and does not interfere with your standard growing routine and operation.

Armada is specifically formulated for Spidermite and Powdery Mildew Problem
Armada is made from 100% Organic Ingredients
Prevents: Bugs, Molds and Mildews
Kills: Spidermites, Powdery Mildew, Aphids, Whiteflys, Gnats, Black Mold, and many other Bugs/Molds
Active Ingredients: Cinnamon, Clove, Thyme, and Peppermint Organic Essential Oils