Several years ago, Eric Mussen was a speaker at an Ontario beekeeping shortcourse. The question about dusting fumagillin came up. Dr. Mussen stated that this method is ineffective.
Bailey in Honey Bee Pathology p.94-95 states "Applying the antibiotic as a dust or in solid sugar candy is ineffective (Furgala and Gochnauer, 1969b) [ Am. Bee J. 109, 218-219]
Perhaps, there is newer research with another answer?
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