Abstract: The fluorescent dye Calcofluor White M2R was applied to stain and identify Nosema bombycis spores. The results showed that the spores were stained in green-blue fluorescence. With this method it is easy to distinguish microsporidian spores from virus, bacteria and fungus spores.

Key words: Nosema bombycis, Calcofluor White M2R, fluorescent staining, diagnosis