Epizootiological studies on the occurrence of densonucleosis in the silkworm bombyx mori reared at sericultural farms
Watnabe, H.; Shimizu, T.
Journal of Sericultural Science of Japan 49(6): 485-492
Epizootiological investigations were made on the occurrence of densonucleosis at sericultural farms in Saitama and Nagano Prefectures [Japan], indicating an enzootic of densonucleosis in both sericultural areas; occurrence of the disease was only noted at a few farms in Nagano Prefecture. Densonucleosis virus was detected in the dust from nearly every farm in Nagano Prefecture, even farms where nonsusceptible silkworm strains were reared and no occurrence of densonucleosis was seen. The virus detected in the dust was derived from contaminated mulberry leaves with a densonucleosis virus which multiplied in the mulberry pyralid, Glyphodes pyloalis, infesting the mulberry plantation. Rearing of the nonsusceptible silkworm strain was one of the best ways to protect the farm from densonucleosis. In Saitama Prefecture, the densonucleosis virus was not detected in the dust from any farm, nor was densonucleosis infection in the mulberry pyralid recognized.