Identification Of Tobacco Viruses In Shanxi Province & Distribution Of Virus Community

The disease of tobacco virus occurs widely, and it is gradually serious. This affects tobacco quality and yield, and has become an urgent problem to resolve immediately. We start to investigate and identify the pathogen of tobacco virus from 2001. It has directed the function of preventing and controlling the virus disease, and is the basis of integrated management.In 2001 year, 165 typical samples were collected in tobacco producing regions in Shaanxi province. Five viruses were identified by biological determination, serological assay(Double diffusion and Enzyme-linked immiuno-sorbbent assay) and electron microscopy observation. The most predominate virus was TMV, and the next ones were TEV, CMV, PVY and TRSV. The rates of their occurrence were 20.61%, 19.39%, 18.79%, 9.7% and 2.4%, respectively. Simultaneously the complex infection of TMV and CMV is also a crucial problem to be paid attention to. Compared with that of 1989-1991 and 1998-1999 years, TMV and PVY have been increased obviously, but CMV, TEV and TRSV have been descended.Additionally, we proceed to investigate the occurrence of tobacco virus in different regions to establish preventative strategy. The result showed that TMV and CMV were epidemic species in Ankang and Xianyang, and the rate of complex infection of TMV and CMV in Xianyang was higher than that of in Ankang; TEV and CMV were predominant ones in Tongchuan and Yan'an., and the rates of TMV were 4.55% and 12%, which lower than that of other regions. The predominant viruses were TMV and PVY in Shangzhou. The disease of tobacco virus, which were transmitted by aphids in Yan'an and Tongchuan, occurred more seriously than in other regions if in dry weather, bad irrigation condition and unreasonable methods of dealing with tobacco stems, and it maybe cause TMV's occurence widely by soil transmission.Detection of tobacco seeds was conducted by the methods of host inoculation and ELISA. The results showed that no virus could be found in the seeds and the seedling was healthy, too.