| Abstract |
This experiment was undertaken to examine the injurious environment conditions for occuring of the virus disease, grasserie and cytoplasmic polyhedrosis in rearing of silk worms, to observe of cytoplsamic polyhedrosis diseased silkworms with histological preparation and to define the virus origin on the gattine and the disease of shrinked form after moulting (Okichijimi). The results obtained are as follows. 1) The grasserie in spring season rearing was remarkably infected in highly percent with 20.1 % in high temperature condition during 3rd to 4th instar, the high temperature during 1st to 2nd instar and 5th instar in 16.5% and 16.3%, respectively. In the fall season rearing, the disease was infected by the feeding of soft leaves plot in 5.3% and 4.8%, respectively with significant difference in 5% level, accordingly, it was thought to the nutritional condition is a factor in occuring of the disease. 2) In spring season rearing, the number of infected silk worms of cytoplasmic polyhedrosis was increased in the high temperature and high humidity conditions, and in fall season rearing, order of the low temperature and high humidity plot, first feeding plot and feeded with hard leaves plot were found insome high infected ratio of the disease than control plot. 3) The occuring of cytoplasmic polyhedrosis was observed even in control rearing plot with the examining of anatomical and histological preparation in spring and fall. 4) It was found that the high diseased ratio of the gattine and disease of shrinked form after moulting in 21.8% of control and 93.2% in feeded with inocylated plot in the biosassay of inoculum. It was defined as a virus flacherie acoording to the Danaka and Shimizu's examine method. |
