The easiest way to control spider mites is to use a natural enemy to eat them, I just order predatory mites from Biotactics www.benemite.com
Get their phone number from website and ask for Barbara, she really knows her stuff and will tell you what you need. The only thing I have found to be...
I just order 10,000 predatory mites from Biotactics www.benemite.com they eat up all the eggs and spider mites, best to apply before you get infested..