Bombyx mori densovirus (BmDNV), a virus that impacts the sericultural industry by destructive damage throughout the rearing of larvae in many farms, has long been seen as a serious problem. The midgut columnar cells infected by this virus contain hypertrophied nuclei where the virus multiplies. Consequently, the nucleoplasm of infected cells is densely stained with DNA-chromophilic methyl green or Feulgen reagent (Watanabe et al. 1976). The infected susceptible larvae become accid and develop diarrhea as midgut tissue is destroyed, a condition known as acherie, and nally die.