On mite killing.. A quick note on this.. the other day I saw some bottom screens
in use which had a metal pan beneath coated with Pam cooking spray which killed
the mites when they fell off the bees.  This was designed to sit on a regular
bottom board.  THe screen was obviously small enough to prevent bees from
contacting the oil.  This, I thought, was a novel idea.  I'm not sure how
effective it is though.
Erick Platt