Identification of Tobacco Virus Diseases Pathogen and Distribution of Virus Community in Shaanxi Province

From 165 tobacco leaf samples collected in the tobacco growing areas of Shaanxi Province in 2001, five viruses, tobacco mosaic virus (TMV), tobacco etch virus (TEV), cucumber mosaic virus (CMV), potato virus Y (PVY)and tobacco ringspot virus (TRSV), were identified through biological determination, serological reaction (agar double diffusion and enzyme-linked immuno-sorbent methods)and electron microscopy observation, and their rates of occurrence were 20.61%, 19.39%, 18.79%, 9.7% and 2.4%, respectively.The complex infection rates of TMV and CMV, TMV and TEV, TMV and PVY were 21.21%, 1.2% and 6.67%, respectively.The infection of TEV and PVY increased obviously in some regions.