... jpms@ira.cinvestav.mx* Corresponding author AbstractAs part of a routine screening for the possible presence of the necrotic strains of potato virus Y affecting potatoes in Mexico, five PVY isolates were submitted ... geographicdistribution of serotypes of Potato Virus Y. Plant Dis 1997,81:481-484.3. Chrzanowska M: New isolates of the necrotic strain of potato virus Y (PVYN) found recently in Poland. Potato Res 1991,34:179-182.4. ... Ronhanyi J, Forster H: Studies on the etiol-ogy of tuber necrotic ringspot diseases in potato. Potato Res1984, 27:339-352.5. McDonald JG, Kristjansson GT: Properties of strains of potato virus YN...