Three miticides (Trilogy, Koromite, Lorsban + Dimethaote) were evaluated under commercial production field conditions for their efficacy and effects on mite infested alfalfa in spring 2003. Mite numbers were collected weekly. Alfalfa yields and quality data were collected at harvest. Data indicated that Koromite provided quickest reduction of spider mite numbers, as well as highest alfalfa yields (+0.18 tons hay more than untreated check). Trilogy treatments resulted in increased internode lengths and finer stem diameters of lower parts of alfalfa than other miticide treatments. This result is thought to be an effect of Trilogy, rather than due to mite control alone.