When I started this hobby a month ago, my local adviser told the class to spray sugar water on the bees in an open hive. He said this keeps them busy cleaning each other. He also said to keep feeding them 1:1 sugar/water until late fall, then increase it to 2:1.
Other people posting here, seem to recommend not using sugar, or spraying. Some seem to think it is a cause of nosema.
Could some knowledgeable people post their thoughts here on the topic? Some explanations of why they think sugar is bad would be helpful. Just saying "Don't do it." teaches nothing.