Rice Grassy Stunt Virus Strain Causing Tungrolike Symptoms in the Philippines. Hiroyuki Hibino, Plant Pathologist, International Rice Research Institute, Los Baņos, Laguna, Philippines. Pepito Q. Cabauatan, Senior Research Assistant, International Rice Research Institute, Los Baņos, Laguna, Philippines; and Toshihiro Omura and Tsuneo Tsuchizaki, Plant Pathologists, Agricultural Research Center, Tsukuba, Ibaraki 305, Japan. Plant Dis. 69:538-541. Accepted for publication 19 November 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-538.

A virus disease of rice causing tungrolike symptoms (yellowing and stunting) was observed in the Philippines. The virus is transmitted by the brown plant hopper (Nilaparvata lugens) in a persistent manner and has an incubation period in the insect ranging from 5 to 21 days. Based on symptomatology, virus-vector interaction, serological reaction, and particle morphology, the causal virus was identified as a strain of rice grassy stunt virus. The new strain was designated rice grassy stunt virus 2 (RGSV-2), and the type strain was designated rice grassy stunt virus 1 (RGSV-1). Aside from causing tungrolike symptoms in the field, RGSV-2 differs from RGSV-1 in pathogenicity to rice varieties. In inoculation tests, rice varieties resistant to RGSV-1 were susceptible to RGSV-2.