From this article
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7405.html which has some good recommendations on controls, both biological and chemical:
"Spider mites frequently become a problem after applying insecticides. Such outbreaks are commonly a result of the insecticide killing off the mites’ natural enemies but also occur when certain insecticides stimulate mite reproduction. For example, spider mites exposed to carbaryl (Sevin) in the laboratory have been shown to reproduce faster than untreated populations. Carbaryl, some organophosphates, and some pyrethroids apparently also favor spider mites by increasing the level of nitrogen in leaves. Insecticides applied during hot weather usually appear to have the greatest effect, causing dramatic spider mite outbreaks within a few days."
I have had fair luck with Neem oil, however it is always the spider mites that determine when my tomato season ends. If I wanted a longer season I would try other oils or the IGR's.
Steve