I think we would all be very happy if a relatively cheap household item like icing sugar turned out to be the silver bullet we had been looking for all along but sadly it isn't.
As Adam mentions it was widely touted probably 15 or more years ago as a "natural" treatment although nobody explained how often powdered cane sugar with accompanying anti-caking agents and maize starch cropped up in wild bee nests. As with most beekeeping wheezes, I had a go. As I recall many of the trials at the time shook off all the bees from the frames into a box and then dusted them en masse and dropped them back onto the frames. It was was apparently reasonably effective at dislodging so called phoretic mites, but seemed incredibly disruptive to the bees. To do this repeatedly seemed to be the very opposite of natural.
The hobby version of leaving the frames in situ and simply nudging piles of icing sugar off the top bars into the spaces used surprising quantities of powder and meant the bees at the top were temporarily literally buried in it plus loads ended up in open brood cells etc which again was not very natural. Bees breathe through pairs of spiracles along their body and what might be the consequence of finely ground sugar dust on those I also didn't know .
I found it so invasive and uncertain as to the effectiveness I didn't continue it and don't know anybody who regularly uses it. So approved miticides for bees it is unfortunately. I am not a fan of using insecticides of any kind inside bee nests but I just don't think non-treatment for varroa is an option in my area, I wish it was otherwise.
As Adam mentions it was widely touted probably 15 or more years ago as a "natural" treatment although nobody explained how often powdered cane sugar with accompanying anti-caking agents and maize starch cropped up in wild bee nests. As with most beekeeping wheezes, I had a go. As I recall many of the trials at the time shook off all the bees from the frames into a box and then dusted them en masse and dropped them back onto the frames. It was was apparently reasonably effective at dislodging so called phoretic mites, but seemed incredibly disruptive to the bees. To do this repeatedly seemed to be the very opposite of natural.
The hobby version of leaving the frames in situ and simply nudging piles of icing sugar off the top bars into the spaces used surprising quantities of powder and meant the bees at the top were temporarily literally buried in it plus loads ended up in open brood cells etc which again was not very natural. Bees breathe through pairs of spiracles along their body and what might be the consequence of finely ground sugar dust on those I also didn't know .
I found it so invasive and uncertain as to the effectiveness I didn't continue it and don't know anybody who regularly uses it. So approved miticides for bees it is unfortunately. I am not a fan of using insecticides of any kind inside bee nests but I just don't think non-treatment for varroa is an option in my area, I wish it was otherwise.
