The goals of our research are to examine the role that naturally-occurring predators play in controlling spider mites and determine if predatory mite releases can improve spider mite control. During 1996 & 1997, we performed large-scale releases of the western predatory mite using low release rates and found that releases did not increase predatory mite numbers and did not improve spider mite control. Thus,we have attempted to identify factors that could be limiting predatory mites in hope that we can improve spider mite biological control. During 1998 & 1999, we completed four experiments…