Three Symptomatologic Types of Rice Virus Diseases Related to Grassy Stunt in Taiwan. Ching- Chung Chen, Senior Specialist, Taichung District Agricultural Improvement Station, Taichung, Taiwan 400. Ren-Jong Chiu, Senior Specialist, Council for Agricultural Planning and Development, Taipei 107. Plant Dis. 66:15-18. Accepted for publication 4 April 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-15.

Three rice diseases with viruslike symptoms were collected from central Taiwan. The diseases were designated as wilted stunt, grassy stunt B, and grassy stunt Y. Their causal agents were all transmitted by the rice brown planthopper Nilaparvata lugens in a persistent manner, with incubation periods in the vector ranging from 3 to 23 days. Symptomatologically, wilted stunt was distinct in that it caused extreme plant stunting and was often lethal to rice plants, especially in the winter months. Both grassy stunt B and grassy stunt Y also caused stunting, but they were not lethal to test plants. All three disease types stimulated tillering in some rice cultivars in summer; only grassy stunt B had this effect in winter. On the basis of vector-relationships and enhancement of host tillering, these three diseases were tentatively identified as virus diseases related to rice grassy stunt.

Keyword(s): planthopper transmission, Oryza sativa, virus isolates.