Causal agent of “waika” disease of rice plants in Japan

Abstract

The “waika” disease of rice plants has occurred since 1971 in Kyushu, Japan. The characteristic symptoms on diseased rice plants are stunting, discoloration and drooping of leaves. The causal agent which was transmitted by Nephotettix cincticeps Uhler and N. virescens Distant, seemed to be non-persistent in the vectors, and was found to be spherical virus approximately 30nm in diameter.