There are many species of spider mites. Many are specific to a particular plant or family of plants, others can feed on a wide range of plant hosts.
Most spider mites feed on the under side of leaves, sucking the juices out of individual cells, leaving an appearance of tiny dots, call stippling. There are some mites like the southern red spider mite that will feed on the surface of the leaf.
The most common spider mite may be the two spotted spider mite. They feed on a very wide range of plants including many flowers and vegetables. Most spider mites like hot weather and their life cycles will increase from weeks to days in hot, dry conditions. Most mites winter over as adults, emerging and laying eggs. The larvae hatches out and feeds, it only has 6 legs. Then they go through 2 nymph stages before becoming an adult with 8 legs.
Before I talk about controls, many products list spider mites on their label, and some do not. Many of these are broad spectrum, killing more of the natural predators of the mites, than mites themselves.
Carbaryl, Malathion & Pyrethroids all fall into these categories. Some actually increase the reproduction of the spider mites. Alsoremember most systemic insecticides DO NOT control spider mites.
The absolute Best product for spider mites is the ferti-lome Horticultural Oil. This is not a dormant oil or like other Hort Oils on the market. There is NO Temperature Restrictions on this product. In the four years this has been out, I have not had any cases of this burning a plant, so do not hesitate
recommending this in hot weather.
Methods of Control
Horticultural Oil has NO effect on the waxy coating on needles so it is your best choice here as well.
Ferti-Lome Triple Action with Neem Oil Insecticide
Another choice is Triple Action, this contains Neem Oil and is a very good natural choice. Although be very careful of temperatures over 90 degrees because it will burn.
HY Dormant Spray
During dormancy, HY Dormant Spray is slightly more effective on over wintering adults and eggs.