I am only a new beekeeper since last year for hobby only but willing to learn and experiment. Last April I was lucky and managed to catch a very large swarm in my neighbours garden. Last year I have collected a lot of pro and con information on 4.9 foundation from the BEE-L messages and from personal contact with the Dee Lusby. Now it only takes a crazy Dutchman living in France to order some packages of 4.9 from Dadant in the U.S. and have it shipped to France. The swarm was directly put on 4.9 foundation and a screened bottom during a honey flow. The swarm hive was set away from the other 5.5 hives with screened bottoms and all checked weekly for Varroa, but no mites were found in all of these 5 months. To me this is clear enough prove that the Varroa mites don't like drafts and small larvae, while the other 5.5 hives have plenty of them. It's just too bad that now at the end of the season I cannot shake the other hives in new hives with also 4.9 and find out what will happen. Next year this will be the first point of action with feeding if need be, but we have to beat the mite somehow to prevent great loses and hardship. And these little bees look so beautiful and active, while wash boarding often seems to be their favorite activity at the end of their working day. BEEHAPPY