An investigation on silkworms presumed to have acariasis in silkworm farms

• Published in: The Journal of Sericultural Science of Japan Vol. 38; no. 2; pp. 168 - 175
• Main Authors: KURIBAYASHI, Shigeharu, HIGUCHI, Tetsumi
• Format: Journal Article
• Language: English
• Published: The Japanese Society of Sericultural Science 1969
• ISSN: 0037-2455; 1884-796X
• DOI: 10.11416/kontyushigen1930.38.168

1. The authors investigated silkworms presumed to have acariasis in 62 farms in the district of Maebashi and its sorroundings of Gumma prefecture. 2. Of a total of 62 cases investigated, 14 were established as damage caused by agricultural chemicals or flacherie or Aspergillus diseases while in the other 48 cases the cause of damage was not determined. 3. Although the symptoms of the affected silkworms closely resembled acariasis reported by AMARI (1917) and others to be caused by P. ventricosus, we did not find P. ventricosus or and other mites injurious to the silkworm either on the body of the silkworms or in their rearing site. 4. On silkworm larvae that were discarded to a compost heap, we found two mite species Macrocheles muscaidomesticae and Uropoda nipponica, previously unknown to be injurious to silkworms. It is of interest to note that both species were located only between the maxilla and the first thoracic legs of the silkworm larvae. 5. During this investigation, 7 kinds of mite species were found in the silkworm rearing site. Subsequent laboratory studies proved these to be harmless to the silkworm. 6. In no case did we find P. ventricosus, generally regarded as the most injurious parasite of all the known infecting mites. 7. These results indicate that most of the damage generally regarded in recent years as acariasis were caused by some unknown origin other than mite, and certainly not by P. ventricosus.