I have a unused pole shed that was once my horse stalls. It has 2 dutch stall doors that are open at the tops, extra open 'windows' and the rafters are open. This is Fla and it is very open (airy). I can place a cardboard box inside about 10 feet up (out of the weather) with lemongrass oil in it. I assume that swarming bees would find it attractive. Do you have any reason to believe that they would not go inside a mostly open pole shed ?
Thanks
Mike