Hello,
I thought I would share my experience with a "varroa blaster". Inspired by a
post from another Bee-l member, I constructed a varroa blaster using a stout
plastic bottle(an old Salsa bottle). Small diameter holes were drilled in
the cap. The bottle was filled about half full with powdered sugar and a
piece of nylon stocking was stretched across the mouth of the bottle. The
cap was screwed on the bottle over the nylon.

Several frames were removed from each super and the remaining frames were
seperated giving each frame face two strong blasts of powdered sugar by
squeezing the bottle.

A tray was placed below the supers being treated to observe mite fall. The
vast majority of mites would fall off the bees within the first minute of
treatment. Approximately 80% of the mites on the bees were dislodged during
the first treatment. Another treatment 24 hours later dislodged almost all
the remaining mites.

Mites on the tray which caught a light dusting of powdered sugar from the
treatment were all dead 24 hours later. Previous tests indicated mites could
live about 5 days on the trays with hive debris. The tracks they left in the
powdered sugar dust were interesting. Some traveled a great distance in a
small area usually less than an inch in diameter before perishing. Most
perished without traveling at all.

No noticable damage occurred to either the larva or the bees although some
newly hatched bees dislodged from the frames during the treatment had
trouble locating the hive entrance. Older bees would fly back to the hive.
Fallen mites on the mite tray were unable to attach or not attracted to bees
walking across the mite tray.

Best Wishes
Dennis Murrell