抄録
Stunted rice plants were observed in rice growing areas of West Kyushu in 1971. Since then, the affected acreage has increased year by year, accompanying severe yield losses. Field observations and experiments were conducted to ascertain a causal organism in 1973. Plant- and leafhopper adults were fed on the healthy rice plants for a 3-day inoculation access feeding period following a 3-day acquisition access feeding period on naturally-infected rice plants. Of the four species tested, Nephotettix cincticeps was found to be capable of transmitting the disease. N. cincticeps was also able to transmit the causal agent to healthy rice seedlings from the experimentally-infected plants after a 2-day acquisition and a 1-day inoculation access feeding period. When the rice seedlings of 1- to 2-leaf stage were infected, symptoms were clear and distinguishable. In addition. infective specimens were detected among the field populations of N. cincticeps by the transmission tests. The mode of transmission was likely to be of semi- or nonpersistent type. There is strong evidence at present that the causal agent is a virus, which would be new one at least in Japan.
