I used a plastic queen excluder in 2 hives last year, and the bees refused to go up into my honey supers. After 2 months I figured I'd better take it off, and a month later the supers were full. I have since learned not to bother with it if there is a layer of honey on top of the brood seperating the nest and the honey supers. Maybe the plastic is "scratchy"? I wonder if wooden ones are better, or even necessary? - Cynthia in Houston, TX