Dave Green wrote:
...
>     Any mites that drop off this colony, would have to move to the building,
> up about 6 feet, then back out along the bottom of the air conditioner. I
> would think few of them would ever be able to get back to the colony.

The thing to remember here is that we're talking about mites.  Mites are not
hunter/gatherers, they're opportunistic blood sucking predators!  The reason
open bottoms (or in this case, no bottoms) are effective is that mites that
fall off do not go searching for a new host, they lie in wait for a new host to
come walking by.  If a new host walks by, the nites hop on.  If no host comes
walking by the mites wait until they die (usually via dessiccation) or they are
predatored by hunter/gatherer insects (perhaps ants) or hell freezes over.

> ... How about a mesh floor with room for a tray underneath?
> Periodically, slide in a tray with soapy water, and smoke the bees with
> tobacco smoke, which is known to make varroa fall off. I believe the soapy
> water would effectively kill any mites that dropped, removing any chance of
> climbing back up.  It would, of course require a specially built bottom board.
>  Any thoughts?

Sounds like an effective plan if you've got the time and inclination.  Actually
it's the same strategy as sticky boards except you've substituted the soapy
water for the sticky board.

Aaron Morris - thinking there's more than one way to skin a mite!