> I was referring to the penetration of cappings in order to kill mites
> ...if amitraz doesn't get into the sealed brood, it can only kill
> phoretic mites ...what is its advantage over formic, thymol or
> oxalic?

Well, formic and the other volatiles work as vapours.  Amitraz works by
contact.  I have not researched its volatility, but I assume it is very
low.  The others are quite volatile and dissipate over time.

> The reported disadvantages of the latter three (occasional queen
> loss, temporary brood setback, etc) are not as bad as the potential
> problem with wax residuals of DPMF, from what I have read, and at
> least the acids don't leave residues.

Correct, but in many situations fume treatments simply do not work
reliably enough, especially as varroa economic thresholds are lowered,
then lowered again.

This deficiency may be due to treatment windows, scale of operation,
location, climate, hive geometry, flow timing, varroa strains of
differing potency ( one explanation for IMO for conflicting reports of
efficacy), operator competency, labour costs, strains of bees...

On this list, we have a wide scattering of situations and intents.  Any
attempt to identify or dictate one best solution for any particular
problem soon reveals that it is not realistic or economic for many.

We try to discuss all alternatives with an open mind and understanding
that our best solution may not be the best answer for someone else.

A single hive top-bar beekeeper in Wales will not see things the same
way as an operation in Alberta with 10,000 hives or a migratory American
beekeeper with 50,000, or a beekeeper in Thailand either for that matter.

An academic with an experimental yard will not see things the same as a
truck driver with a few hives.

> I suppose if the combs are rotated out regularly, then the risk of
> DPMF buildup is minimized.

This has not seemed to be a problem in  practice, although in theory it
is.  Coumaphos definitely was a bad one that way, though, and resulted
in a lot of comb being culled.

> And since the DPMF is the toxic metabolite that builds up in wax,
> that is a good enough reason to rotate out combs all by itself if
> using amitraz, even without considering all the other junk that
> builds up in the brood comb.

I don't know of any commercial beekeepers who currently cull comb
strictly for reason of build-up alone (Horace Bell did at one time, but
that was for different chemicals).

Commercial beekeeping is hard enough on equipment that normal turnover
and replacement is sufficient.  That is not to say that in future we
won't see a problem.  Medhat indicated he is trying to get some metrics
on this.

> It seems to me that for small-scale beekeepers the organic acids and
> thymol are better options, especially where treatment is not well
> standardized (i.e. people don't follow instructions).

That definitely is one way to go, but the reason we are even discussing
Apivar here as much as we are is that many are not getting satisfactory
results with just those options.

Apivar is the"nuclear" option right now.  In Alberta, Apivar is used
in conjunction with the others, (but oddly enough, an Alberta commercial
beekeeper got a big fine for using one of the commercially prepared
thymol products).

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html