Preliminary Identification of Tobacco Viruses in Xianyang and Shangzhou City of Shaanxi Province

101 virus samples were collected in tobacco producing regions in Xianyang City and Shangzhou City of Shaanxi province in 2001. Five viruses were identified by biological determination, serological assay (Double diffusion and Enzymelinked immiunosorbbent assay) and microscopy observation. They were tobacco mosaic virus (TMV), cucumber mosaic virus (CMV), tobacco etch rirus (TEV), patato virus Y (PVY) and tobacco ringspot virus (TRSV). Tobacco mosaic virus (TMV), cucumber mosaic virus (CMV) and tobacco etch rirus (TEV) were the most common viruses and caused serious losses in fields. Simultaneously the complex infection of tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV), patato virus Y (PVY) and tobacco mosaic virus(TMV) are also a crucial problem to be resolved at present.