Allen Dick just reminded the list of the devastating effect of Tracheal
Mites, and outlined the preferred treatments.  As we have all come to expect
from Allen, his advice is sound and well reasoned.  However, I would like to
add another approach, more or less completely contrary to Allen's.

My suggestion is to not treat for Tracheal Mites and to instead "take your
losses", and make your small contribution to developing wide-spread
resistance.

In general, I think we all agree that it would be best if we did not have to
treat bees for any disease.  Despite that general feeling, we either have to
treat for Varroa or lose our colonies (assuming we have more than 50 or so
colonies so that it is impractical to rely on freezing drone brood several
times a year).  American Foulbrood is next on everyone's list...but many or
most hobbyists do not have to treat and should try to keep it that way.  The
single best preventative is to NEVER accept brood combs or honey frames from
someone unless you feel positive they would tell you if they had any history
of AFB.

Breeders have done a good job at selecting for stock that is resistant to
Tracheal Mites.  If you buy queens you can get that stock by buying New
World Carnolians (NWC's), or from any of the cooperators in the Ontario
Queen Project.  NWC mother stock comes solely from Sue Cobey at Ohio State,
and has been tested for many years as having Varroa infestations of less
than 2%.  One California breeder who buys her stock (at $500 each, and up)
and uses that to produce queens that are open-mated and sold to you and I,
has had progeny from his open-mated queens tested and found that "only" 30%
were infested with Varroa.  Given the open mating, that is remarkably low.
I understand that the infestation rates for members in the Ontario project
are much lower...less than 10%, in general.  However, I am personally leery
of this claim because the colonies are treated with formic acid.  (The NWC
colonies receive no treatment for Tracheal Mites.)

And there are many others producing resistant queens...Kirk Webster, those
producing the lines of Russian queens, etc.

My own 100+ colonies have not been treated for Tracheal Mites in many years.
Every year I know I lose some to the effects of Tracheal infestation, but I
consider that a price paid along the way to wide-spread resistance.  I mourn
the losses, but at fewer than 20% of my hives, they are certainly at an
acceptable level and are quickly replaced by splits.

So, make your choice as you will but please at least consider not treating
at all.

Lloyd
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Lloyd Spear Owner, Ross Rounds, Inc.  The finest in comb honey production.
Visit our web site at http://www.rossrounds.com.