Takao Shimizu

Mulberry pyralid, Glyphodes pyloalis: Habitual host of nonoccluded viruses pathogenic to the silkworm, Bombyx mori

Abstract Larvae of the mulberry pyralid, Glyphodes pyloalis, which infest mulberry plantations, are frequently infected with nonoccluded viruses that are serologically indistinguishable from the densonucleosis viruses (DNV-1, DNV-2) and the infectious flacherie virus (IFV) of the silkworm, Bombyx mori. Histochemical and electron microscopical investigations of presumably normal mulberry pyralid larvae reveal that the viruses multiply only in a very small number of midgut cells and cause a chronic nonlethal infection. When silkworm larvae are fed with a suspension of macerated pyralid larvae infected with viruses, severe typical densonucleoses and infectious flacherie develop at high frequencies. Our results suggest that Bombyx DNV-1, DNV-2, and IFV originated from the Glyphodes nonoccluded viruses, and epizootiologically, the mulberry pyralid is a common habitual host of these nonoccluded viruses.