About open feeding being an invitation to the neighborhood bees, who may come complete with all manner of problems. Let us not forget that one form of open feeding is a nectar flow. I very much doubt that a field of bloom will be monopolized by only one apiary if there are others within flight distance. Personally, I do not do open feeding because of the robbing potential and the difficulty of controlling the feed input to individual colonies. But I wouldn't consider open feeding to be any more of a disease/mite spreading risk than a blooming locust tree. W. G. Miller Gaithersburg, MD