Pesticidi i Fitomedicina (Jan 2007)
Identification of Potato Virus Y Strains in Tobacco Crops
Abstract
Five viruses: Potato Virus Y (PVY), Tomato Spotted Wilt Virus, Cucumber Mosaic Virus, Tobacco Mosaic Virus and Alfalfa Mosaic Virus, of which PVY was predominant, were detected by serological testing of tobacco samples collected from many localities in Vojvodina in 2006. Viruses are the most important pathogens in tobacco and PVY causes considerable economic damages all over the world. A PVY population comprises several different strain groups, strain subgroups and recombinant strains. Among these, PVYN (necrotic strain) and PVYO (ordinary strain) cause the greatest yield and quality losses in tobacco. Identification of a prevalent strain in a PVY population is the basis of proper tobacco genotype selection for resistance against this significant virus. Typical symptoms caused by PVY were observed by monitoring tobacco crops in our country in 2006. The symptoms occurred as changes in the general plant appearance, as well as necrotic areas on leaves, petiols, stems and flowers. The initial symptoms of veinal necrosis were expanded throughout the leaf, causing reddish-brown (copper) plant color and premature death of lower leaves. Plants with these symptoms occurred in all monitoredlocalities and their frequency was high.In order to understand various epidemiological aspects of the diseases caused by PVY and to prevent its occurrence and spreading in tobacco crops, it is necessary to properly identify this virus in time. Biological, serological and molecular identification of the virus and its prevalent strain was carried out in order to determine tobacco disease ethiology. The results obtained suggest that this prevalent strain of PVY has been spreading progressively in our country in recent years. Although PVYN is widely spread in tobacco crops in Europe, its destructiveness, disease intensity and wide distribution in Serbia were established only in the last two years.PVY necrotic strain was detected mainly in single infections, although it was also present in mixed infections with other tobacco viruses.
