One of our club members suggested that when mite levels are higher we should treat even though the supers are still on. In my case they will be on a another 3-4 weeks given a slow season. I will not be treating withy supers on even though the treatment is supposedly from an organic source. Does anyone treat with supers on? I assume commercial beeks do as they have another situation to deal with.
Yes; It is easy to pry up front or rear of the stack of supers and insert a piece of sheet metal, corrugated plastic, etc., which is a bit more than half a hive in area, then lift the other side enough to insert another sheet big enough to cover the remaining area at the other end. The sheets overlap slightly. Much easier than trying to insert full sheet at one go.
Do your vaporization below and no OA gets into the honey in the supers. Reverse procedure after the dust has settled. You do not have to pile off the supers individually and deal with robbing. Functionally you have removed the honey supers during treatment of the brood boxes below.