Hi: Well, I can assure you all that 3000+ feet has no discernible effect on supressing varroa mites. In Montana, most of us live at that elevation or higher. For example, Bozeman and Butte are above 5000 ft. We all get varroa mite and it kills our bees. Last two years, our hobbiests have all got it and their colonies are dropping left and right, unless they treated. Jerry Bromenshenk The University of Montana Missoula, MT [log in to unmask]