>>> ...you suggested that I could not prove I killed them and they
>>> the mites I thought I killed might have died anyhow.

> My point is that I feel that it is shortsighted to focus upon how
> many mites were killed. To my way of thinking, the only meaningful
> way to test the efficacy of any treatment would be to compare the
> normalized trends of mite infestation rate (not total mite numbers,
> which are relative to colony size) over time comparing a number of
> control colonies to an equal number of treated colonies.

This makes a lot of sense. The questions are 1.) how to do it and 2.)
whether anyone has been doing anything like this.

Can we compare the efficacy numbers we have been given by various observers?

This discussion began back when I was trying to evaluate OA evaporation
and came up again when Medhat reported an efficacy number for Hopguard.

FWIW, I declared my fall and winter OA treatments last year to be a
failure regardless of the number dropped, after finding higher than
expected varroa at the end of August this past summer.  I threw in the
towel and used Apivar last fall.

One of the questions about efficacy measurements that were implied
above, perhaps intentionally, is that a highly efficacious treatment
might actually cause a rebound afterwards and perhaps a higher load than
would have otherwise have been the case.

One could speculate that the treatment could eliminate the weaker mites
and leave only the fittest to reproduce.  Using such treatments, if this
be the case, could mean that the problem gets worse over time, rather
than better in spite of short-term apparent success.

This may be why some who go treatment free are able to continue if they
are fortunate enough to have all the necessary factors in place to have
an equilibrium between mites and associated maladies and the bees.
Treating could tip the balance, as it intended to do, but also set up
the operation to need future treatment.

(Mechanical treatment methods like drone brood removal would seem to me
to have the advantage of not bolstering mite population fitness in the
way that chemical methods could).

Such an equilibrium tends to be quite tenuous.  While it may be possible
in a small, non-critical operation, is not sufficiently reliable for
migratory of large commercial operation at this point in time.  That
said, the migratory experiments and documentation by Bob Danka and his
group indicate IMO that the day is approaching where relatively varroa
treatment-free commercial migratory operation may be more feasible.  (In
these tests, I understand that the observed colonies were always
relatively new and not more than two or at most three years old).

The fact that finding that equilibrium was impossible at all when varroa
first hit and is being seen with increasing frequency indicates to me
that we can expect varroa to be much less of a problem in the
foreseeable future.

In the meantime, we are faced with the question of how to calculate
efficacy for treatments.  Given the variety of solutions and the varying
timeframes I am not certain that any one method can be used.  We need to
measure 1.) immediate effect and 2.) observations at a later date, both
compared to controls.

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