Here's a take from another expert, the maker of Bee-Quick:
02-22-2007, 08:30 AM
> Can you use powdered sugar from the grocery store?
> I heard there were anti caking agents in the
> sugar so you shouldn't use it.
Nope, that was and still is bogus info.
Plain old Domino's 10x works great.
The small amount of starch won't hurt anything.
The scare stories about the sugar killing open
brood were bogus, as people were remembering
(or running across old comments) about that
problem from the days when antibiotics were
mixed with powdered sugar (TerramycinÂ®, which
is oxy-tetracycline), and "dusted" on the hive.
Tetracycline can and will kill open brood.
Sugar won't kill anything.
Doesn't even kill the mites, it just makes them
loose their grip, and fall, which is why you
need a Vaseline-coated sticky board to trap
the little beasties, or they will crawl back
up into the hive after they clean off their