Red Spider Mites are an arachnid, having 4 pairs of legs, no antennae and have a single oval body. They live on the underside of leaves and since they are about the size of the period at the end of this sentence they somewhat hard to identify. Adult spider mites will pierce the plant cell and suck the fluid, leaving tiny specks that are visible to the naked eye.
Spider mites do best in hot, dry conditions. When conditions are ideal eggs can hatch in as little as 3 days and mature in 5 days. Females lay 20 eggs per day for 2 to 4 weeks. 1 female can spawn a population of over 1 million mites in one month. With that information in mind you can see why early detection is so important. It is easier to prevent a spider mite problem than to cure one.
Make a habit of regularly checking your plants. Because spider mite are so tiny use a hand magnifying glass and check the underside of the leaves, looking for adults, eggs or damage. There will also be signs of webbing or a dusty appearance on the leaves. If you suspect you are starting to get a problem put a white sheet of paper under the leaves and gently flick the plant, if you see little dots that move it is most likely a spider mite. It is also a good idea to take your magnifying glass with you when buying new plants so as not to import a problem.
Depending on how closely your plants are spider mite can easily move from one plant to the next. If practical quarantine infested plants. A strong blast from the garden hose will knock the adults off your plant, if your doing this with a potted plant be careful that your not washing the mites off to other plants. Misting the plants also helps as the spider mites prefer low humidity.
Biological control is the next step. General predators, such as ladybugs and green lacewing attack spider mites as well as aphids, scale, whitefly and mealybugs. They attack both the adults and their eggs. Also available are Spider Mite Predators, spices specific beneficial insects that only feed only on spider mites and the eggs. These include
P. persimilis, M. longipes and N. californicus. Depending on how bad the infestation is more than one release may be needed.
The other option is chemical control. Soft Chemicals like insecticidal oils and soaps will work on the adults and will need to be reapplied every few days until no sign of the adults are present. Spider mites are not effected by regular insecticides, when shopping for a chemical spray check the label to see if miticides are included. Unfortunately miticides do not effect the spider mite eggs so re application is necessary. Because the spider mite experience accelerated reproduction they can develop resistance to chemicals. You you notice that happening switch to another spray.
The one thing to remember with spider mites is that they are easier to prevent than to cure.