Abstract
Rice dwarf virus has been transmitted mechanically from viruliferous insects and from diseased leaves of rice plants to its insect vector, Nephotettix cincticeps Uhl. by injection using glass capillaries.
It appears that the concentration of virus in viruliferous insects is somewhat higher than that in the diseased leaves. The concentration of virus in eggs laid by viruliferous female leafhoppers, seems to be nearly same as that is viruliferous leafhoppers. When the extracted juices of viruliferous leafhoppers were stored at 0°∼4°C., the virus survived for 48 hours. When viruliferous insect and affected rice leaves were frozen and stored at -30∼-35°C., the infectivity was maintained up to one year. By heating small glass tubes containing the extract of viruliferous leafhoppers in hot water for 10min., the thermal inactivation point of this virus was shown to lie between 40°and 45°C.
