Hmmm. You can dust with powdered sugar whenever you feel it is appropriate. The bees are unlikely to consider dry powdered sugar as food, and the amount of sugar used in a dusting isn't really that much in terms of feeding sugar anyway.
Note that dusting with sugar is a mechanical mite control - interfering with the mite's ability to grip the host bee, and will only affect mites on emerged bees. Dusting doesn't kill those mites. Sugar dust won't do anything for any mites that are in capped brood cells. You may need to dust on multiple occasions to have a real impact on mites.
Note that dusting with sugar is a mechanical mite control - interfering with the mite's ability to grip the host bee, and will only affect mites on emerged bees. Dusting doesn't kill those mites. Sugar dust won't do anything for any mites that are in capped brood cells. You may need to dust on multiple occasions to have a real impact on mites.
