Chris said, about sugar dusting and screened bottom boards:

> The hive headed by my queen #54 dropped 2 mites in the 24 hours ending 8.
> Sept.  The same hive dropped 46 mites in the 24 hours ending 4 Nov.  At the
> beginning of the 24 hour period ending 11 Nov I poured powdered sugar
> liberally on each seam of bees.  The drop was 39 mites.

> You can't dump a promising theory on the basis of 1 test on 1 hive, but it
> doesn't inspire confidence.

I think you are on the right track in using a varroa screen as PART of your
varroa-control program.  I can offer three possible reasons why your specific
test results were indifferent, if not disappointing:

1) Given the limited amount of brood rearing one might expect in November
    in Britain (assuming that you are still in Britain), one would expect a very
    small number of reproducing mites.  Mites that are not there will not
    drop.  Some of the mites in any hive will apparently survive anything short
    of a direct hit by a tactical nuclear weapon.  What was the mite drop
    a week AFTER your sugar application?  What about the week after that?
    What was it the year before at the same time?  I think you get my drift...

2)  Multiple sources say that Varroa mite "collapse" tends to happen
     in late summer.  Since your test hive clearly survived into the fall,
     one can conclude that the mite population was limited before you
     applied sugar.  Survival of the colony alone implies that they had
     somehow escaped a significant mite build-up.

3) Also, if you "poured" sugar on the bees, you were not "dusting" the bees
    at all.  You don't want to bury the bees in sugar.  You want to create
    a cloud of the smallest-possible particles of sugar, much like the
    one created when a woman uses a powder-puff, and direct that "cloud"
    at the bees, one frame at a time, both sides.  The only sugar particles
    that "work" are the ones that are on the order of 5 microns in diameter.
    Larger particles do not "gum up" the "suction cup"-like feet of the mites.

I'd like to point you to the work of Dr. Kamran Fahimzadeh, who has
published several of his papers on "sugar-dusting" in the American Bee
Journal,  most recently one in the Nov 2001 issue.  The first was in the
summer of 2000.  He explains his tests clearly enough to allow anyone
to reproduce his results.  The good news is that his results appear to
be reproducible, and the cost of doing so is within the budget of anyone.

In my view, the value of sugar dusting is that it can knock down serious
numbers of mites, and the value of the screened bottom board is that
it can insure that mites knocked down stay down.  Together, they are
a deadly combination for the mites, but zero risk to bees and brood.
The time to use sugar dusting is when you notice a significant increase
in the "natural" mite fall, which will be in the hottest months of summer.

If you try your same approach on a hive that you have monitored and
designated as "clearly having a mite problem", you will see just how
effective the approach can be.  Like much of beekeeping, sugar-dusting
is a technique, and needs practice and fiddling to "perfect".

I am doing just fine with a very low-tech "baby powder" plastic bottle
(with the holes in the top), a window screen insert below the cap, and
a stainless-steel ball bearing in the bottle as a sugar-clump pulverizer,
and a label that says "007", as usage instructions -

1)  The bottle should be "shaken, not stirred"
2)  The bottle has a "license to kill".

(My earlier posting on the subject mentioned pre-sifting the sugar.
Don't bother, you don't really need to.  Just shake the bottle.)

Any study that tests a screened bottom board as a stand-alone
tool is, in my view, pointless.  It should be obvious to even the
casual observer that the mites can "hang on" in sufficient numbers
to thrive, since they come from a part of the world where feral bee
colonies abound, and make their nests "in the open", which would
be the ultimate "screened bottom board".

But, combine a screened bottom board with sugar-dusting, a
sure-fire knock-down technique that can be used at the whim of the
beekeeper, even with "supers on", and you start to get somewhere.

That said, you cannot expect to eliminate varroa with this, or any
approach, but you can "break the build-up cycle", and push the
varroa population back down to "spring" levels in mid or late summer.
(The alternative for traditionalists would be to remove honey supers, and
treat with a miticide above a screened bottom board.)

I've said it before - Dr. Fahimzadeh deserves a sliver-plated hive tool,
his weight in Euros, and a shiny new pickup truck or car in any color
he wants for doing the basic work on powered sugar as an IPM Varroa killer.
Well, maybe he'd rather have two hive tools, and not the Euros.    :)

It will take some time for others to replicate his work and "verify" his
results, so give it a try yourself, and see.  I did.  I'm convinced, and
I'm not at all easy to "convince".

        jim

            farmageddon (where the local children want to put
                                 "Power-Puff Girls"** stickers on my
                                 bottles of "mite killer powdered sugar".)

              ** see http://www.cartoonnetwork.com/POWERPUFF/