Every winter I have had an infestion of spider mites. This year NONE. This you would not want to take place in your home and you will have to be very careful if this happens in your greenhouse but a bunch of wasp moved into my greenhouse in the fall. You can see them clinging to the tops of many of my plants at any time. I am careful when I am in there but it has been wonderful not to loose my plants. They have not been aggressive to me at all but just seem to be interested in eating. I do not heat the greenhouse so at times it was in the upper 30s in the winter.

Patsy

Here's the official Master Gardener scoop on Spider Mites:

They thrive where it is DRY and HOT. If you hit the plant hard with a stiff spritz from a hose (especially under the leaves, where they live), you will knock them off, and they can't climb back up. You have to keep spritzing every few days to wash off the newly hatched mites.

Spider Mites thrive on houseplants in particular, because it's dry as well as warm. If you hose off your plants regularly, or put houseplants in the shower, it creates an inhospitable climate for them and they'll leave or stay away.

Trying to kill them with insecticide involves spraying the underside of every leaf, and is ineffective. I live in the desert, and regularly hose down all my plants (and my clients'). This also cleans off dust and pollution, which interferes with photosynthesis.

Hope this helps.

Keep those plants wet!

I get spider mites regularly, as it is so dang dry here. If I forget to water a plant once; BANG! Mites. I also regularly scare the buggers off. I back up Pansy Soup from a high desert perspective. One thing I will add, however, to the washing and keeping moist: If one can afford to put the plant in a bigger pot. (Without discouraging flowers or aesthetics.) It will not dry out as fast as a small pot. It helped me with those forgotten Passiflora waterings.

(A note on the wasps: They may be attracted to the nectaries on Pass, a bribe for the wasps to protect the vine.

James

I have the same problem with my tree for 3 years in the row! First year, I tried to use the spay, but in the following year toward the Fall, same thing: all tree is covered with spider mites. Tree is too big now, where it is impossible to just spray it. Is there any known medicine for plants to water with may be???

I've had fairly good luck with predatory mites- Got 'em from Natures Control- http://naturescontrol.com/

How big is this tree? I've got a lil star-fruit tree that pretty much gets its ass handed to it if the mites get on there.. Plus various passis are *really* susceptible. I put 'em all in the 'sick room' & get the humidifier going.. Then dose everyone with the predators. 'Course up here I've got everything in pots so I can bring them in for the winter. (snow)

had a problem with white flies over the winter as well.. Sucked.

Anyway- Yeah. Call that nature's Control place. I think the guy's name is Nathan- He hooked me up, surely will have some suggestions for you.

Spider mites are not insects, and some insecticides will actually stimulate them to reproduce faster. You need a miticide, and Floramite is one that has worked really well for me. It is expensive, but you can find it in small quantities on ebay, 1 oz. $23, which will last years, as a little goes a long way.

If mechanical methods aren't effective Neem oil is the best and will not kill beneficial insects or yourself. It is also a foliar fertilizer, fungicide, and biodegradable.

I use a systemic. Mites only seem to really attack Incense for me, so that one passie gets a bit right after coming into the house. I've not had problems on others (except for Vitifolia, but I lost that one last spring and haven't replaced it...well I did replace it with Lady Margaret).

Lavender Lady, Capsularis and others I bring in are largely unaffected.

~Chills

I had a mite problem on my mollissima. I have no luck with Neem on anything and don't like to use man made chemicals but I really had no choice. It was either my plants or the mites. I have used two miticides, Forbid and Floramite. Both work wonders and are mite specific. Floramite is even specific enough that it spares many beneficial mites. The only drawback to the miticides is the cost. They are both pretty expensive.
Karyn

Try two to three drops of castile soap for every quart of water. Spray on plant, on top and under leaves.

I just read about liquid seaweed on another forum. Anyone have any experience with this???
Roxanne

Roxanne I use seaweed (kelp extract) as a nutrient, not a miticide. I have heard of using fish emulsion as an insecticide but tried it and wasn't impressed.

Krstofer, if the Bayer systemic you've tried is Imidacloprid, it should do a good job on spider mites. You might also try Spinosad. It's a fairly new product and I only have limited experience with it. but it seems to work very well. Spinosad has also been approved by the National Organic Standards Board (see http://www.nysaes.cornell.edu/pp/resourceguide/mfs/13spinosad.php)

Here is a link that might be useful: Spinosad info

We have spider mites now (May) attacking our tomatoes that we kept alive alive all winter in our greenhouse. We have been getting ripe tomatoes for 4 weeks, and now these spider mites are killing our plants. Very discouraging! Does anyone know if spider mites cause the lower leaves and stems to yellow and gradually die? And our tomatoes now have a yellowish orangish speckled skin on the fruit instead of a even red color. Is this also from the mites?

I can assure you that a dry atmosphere is not the only thing to encourage spider mites.. high natural humidity and rain do also. Let me explain.
I live in the Dominican Republic and in our winters its around 75f with 100% humidity most of the time because of all the rain, constantly. Even so, in all my life I have never seen spider mite run so rife on almost any plant life it feels like.

I am going to take the advice of those that have offered it and try a few things out that ive not yet tried. However, why I am writing is to say.. it is not a dry atmosphere that encourages them.. as explained.. it happens also in months of high humidity.

Miticides like Forbid and Fluromite work extremely well and contain an ovacide so repeat applications are not necessary but I don't know if they are safe to use on edible crops. You can look them up online.

I use Quantum Apocalypse Neem soap concentrate. Way less toxic and environmentaly friendly. kills both the mites and the eggs. within 10 days you can be completly spider mite free using this organic product.

I have a large area of azaleas and other shrubs infected with spider mites. Not sure how to attack so many bushes. It's not like I have one plant that needs help. Any ideas for massive control? Without it costing a small fortune?