>If a colony has foulbrood and the bees visit the open feeder the spores could infest the water and be transported to other hives. I doubt foulbrood spore concentration on bee bodies is high enough to transfer into the feed for other bees to carry back to their hives in sufficient concentration to cause an outbreak of foulbrood. There should be no spores in the feed unless you mix in honey from foulbrood colonies. What could potentially happen though is this: after the open feed is exhausted, greedy bees scatter looking for weak colonies to rob. If such colonies are weak due to a loss of brood to foulbrood, their contaminated honey will end up in the robbers' hives. Foulbrood spores are very numerous in the honey and wax of colonies with clinical symptoms of foulbrood. Some say though that you can take the bees [alone] from an infected colony, hold them in a box for 3 days [so they digest the honey with spores in their stomachs], shake them into new equipment and not get foulbrood symptoms. Winston published that bee stomachs filter out most spores [, pollens and other particles] in the honey in about an hour. I don't recommend this approach since the official NY state policy is to burn colonies with clinical symptoms. A lot of beekeepers inappropriately try to contain foulbrood with terramycin only to preserve and spread foulbrood. No, I don't believe opening feeding spreads disease but I know it results in a disproportionate distribution of the feed. Just like with nectar gathering, the strongest colonies will gather the lion share of the open feed. If the strong colonies have ample stores to start, they will plug up the entire nest as well. The needy colonies are not helped by this unless you later redistribute frames with stores. In-hive feeding, and only as needed, is the way to go. Waldemar Long Island, NY -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---