In addition to Gordon
 
\    1) Drone Trapping.
\
\    Divide a frame into three sections, fit  a  starter  strip  of
\    foundation  and place this near the outside of the brood nest.
\    The bees will (probably :-) draw drone comb on this (which  is
\    what  we  want).  Varroa prefer to lay in drone comb so we can
\    cut these sections out in rotation (one per  week)  whilst  we
\    find  a  significant  infestation.  Makes a significant energy
\    loss for the colony as they put a lot of work into the  drones
\    we kill.
 
Mite trapping in brood cells will be most effective when all the mites are on
the bees. During a broodless period in your swarm prevention method, you can
trap the mites from the bees in a drone trapping comb with larvae from the
same or another colony. Many variants can be figured out. Important is that
in a otherwise broodless colony only 500 drone cells per kg bees (ca. 10.000
bees) will trap over 95% of the mites!
 
\    2) Trapped Queen.
\
\    Trap the queen onto a (preferably unused) frame using a  frame
\    sized  cage  of QX material to trap her on that frame.  A week
\    later transfer her onto another similar frame and do it again.
\    A  week  later  do it again, then remove and destroy the first
\    comb which by now will be sealed.  A week  later  release  the
\    queen  and  destroy  comb  two, in the final week destroy comb
\    three.  A powerful method because the mites have no choice but
\    to  lay  in  the trapped frames.  Knocks the colony back a bit
\    though.
 
Worker brood can be treated with formic acid outside the colony. 30 ml 85%
formic acid on beer spils together with worker brood combs in one brood
chamber sized extrudated polystyreen box (easy to make yourself, use
polyurethane glue) sealed airtight for one and half hour will kill the mites
and leave the brood undamaged. (The brood has to be at least 9 days old and
preferably not older than 18 days). The more worker brood you will treat in
this way, the more mites you will kill. Therefore, other age-structuring hive
management methods, like queen-arresting in bodies simply with queen
excluders can very well be used. Always treat at least three batches of
capped brood!
 
Good luck!
 
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