I have also been using Dr. Fakhimzadeh's "sugar dusting" method.

I am encouraged by the much lower mite counts in both periodic
"sugar rolls" of bees and mite counts on sticky boards on hives
where I sugar dust.

I am also encouraged by the impact of sugar dusting in terms of
short-term mite fall after dusting.  I never saw as many mites on the
sticky board after 48 hours of Apistan treatment as I saw the first time
I sugar-dusted a hive.

I keep my sugar dry as follows:  I pre-load small jelly-sized canning jars
with sugar on a dry day, seal them, and connect them to my home-brew
spraying gadget just before use.  My spray gadget uses a canning lid with
a screen insert as the "sugar cartridge" fitting.

Rather than adulterating the sugar, I add a small amount of rice to each jar.
This is an old trick, used in salt shakers to keep the salt from clumping.
The rice absorbs moisture, but is both blocked by the screen mesh
on my blower gizmo.

Clearly, humidity is a potential problem, so I try to pick dryer days to dust
the bees.  I assume that a humid day could cause many of those tiny 5 micron
sugar particles to clump into useless 10-20 micron aggregations.  Not having
a scanning electron microscope handy, I am forced to guess at this.  :)

I don't know why the "sugar roll" has been promoted by so many as a diagnostic
tool, while Dr. Fakhimzadeh's sugar treatment has not.  It would seem obvious to
even the casual observer that any method that works so well as a diagnostic would
also have excellent potential as a treatment.

At EAS 2000, the sugar roll was enthusiastically demonstrated in well-attended
apiary workshop.  When asked about sugar dusting hives, the workshop leader
made an anecdotal and somewhat apocryphal claim that sugar dusting entire hives
caused the bees to rip open sealed brood cells where sugar had lodged.

I have gone so far as to shake all the bees off a frame of brood, and completely coat
the frame with a "snowstorm of sugar".  I've yet to see a single brood cell ripped open
as a result, and I've done this several times with different hives.  (Note - all my bees are
[Weaver] Buckfast, so I don't know what other types of bees would do about sugar
lodged on a sealed brood cell.)

I'm still using varroa strips in the fall, but when supers are on, I'm depending on the
sugar dusting to keep the varroa counts low.  It clearly works.

                 jim
        Farmageddon Apiaries