SEROLOGICAL MONITORING OF RICE TUNGRO DISEASE DEVELOPMENT IN THE FIELD - ITS IMPLICATION IN DISEASE MANAGEMENT

Rice tungro bacilliform virus (RTBV) and rice tungro spherical virus ( RTSV) were monitored in transplanted rice (Oryza sativa) by latex test or by enzyme-linked immunosorbent assay (ELISA). RTSV was detected 1 wk after transplanting, and the incidence increased rapidly within 2-3 wk. Dual infection by RTBV and RTSV was detected 2 wk after transplan ting. The infectivity of leafhoppers collected in the field correspond ed with the disease development. However, the development of the tungr o disease differed in cultivars with vector resistance and in differen t planting seasons. The main tungro infection occurred after transplan ting, based on the results of covering plants with mesh screens, setti ng up an unprotected nursery in a tungro-affected field, and treating with insecticide at different growth stages of rice.