摘要 : A new disease was recorded to occurring naturally in field grown bulb and seed crop of onion cv. Hisar-2 in northern India. Symptoms of the disease comprised hay coloured and water soaked spots of irregular shapes and sizes on lea... 展开 A new disease was recorded to occurring naturally in field grown bulb and seed crop of onion cv. Hisar-2 in northern India. Symptoms of the disease comprised hay coloured and water soaked spots of irregular shapes and sizes on leaves of bulb and seed crops. These spots were also observed on the scapes of seed crop which caused drying and lodging of crop. The transmission of disease by mechanical inoculation and Thrips tabaci was found to be 62.50 and 54.17%, respectively. Many plant species showed chlorotic local lesions, whereas some showed curling and twisting of uninoculated leaves. Asphodelus tenuifolius, Chenopodium murale, Physalis floridana, Nicotiana tabacum cv. White Burley and Zinnia elegans were reported as new hosts for the first time. Double antibody sandwitch enzyme-linked immunosorbent assay (DAS-ELISA) studies demonstrated that the OD ranged from 1.02 to 1.31 after the first hour and increased further between 1.23 to 1.96 after 2 h at 405 nm. This virus was identified as iris yellow spot virus (IYSV) on the basis of symptomatology, transmission, host range and serological studies. This is the first report of IYSV on onion from northern India. 收起