1. Queen excluders allow workers to pass through, but not queens or drones. They're most commonly used to keep the queen confined into a lower brood area, and let workers store honey above. We can't extract honey from frames that have brood in them, because it contaminates the honey. 2. I would use OA vapor on an overwintered colony in late April just to assess the mite load. If the drop is low, I'd treat again during a summer brood break. If not, I'd treat every 7 days for 4 weeks.
And What do we do if we have a lot of drone comb? We have a lot of frames with only drone comb. From my understanding they will not lay workers bees in drone comb? So how do I make the frames available for worker comb?
I can't tell what "a lot of drone comb" means. I recommend you take pictures of the frames and post them on the Midnight Sun FB page. That way I can tell if you have a normal ration of drone to worker comb, or if a previous laying worker colony ruined a lot of worker comb by laying it up with drones.
I'm a member of several FB groups. In Alaska, I recommend Midnight Sun Bee Club. I'm also a member of SBGMI (Sustainable Beekeeping Guild of Michigan), which has really good northern beekeeping content.
