I've heard the Commercial greenhouses use sulfur vaporizers to deal with that and other mold/fungi and most insect pest(although the research I've done most say it will put a dent in spider mites, but won't run them completely out), but works well for thrips and white flies if you've got problems with them. I was reading one guys post on another forum site(he's from Seattle), and he said with the R/H there he's got to use a vaporizer once a week or he gets all kinds of things.