A potyvirus known to be an important agent involved in causing a disease of trailing petunias, was identified as being a member of the necrotic strain of potato virus Y (PVY) using a number of monoclonal antibodies. The sequence of the coat protein gene for the PVY isolate was determined and when compared with sequences for other PVY strains it was shown to cluster closely with isolates of PVYNTN and to have a recombination point present within the coat protein common with other isolates of PVYNTN. When inoculated onto potato tuber necrotic ringspot disease (PTNRD) susceptible potato cultivars the petunia isolate was found to be capable of causing necrotic tuber symptoms, consistent with those caused by other isolates of PVYNTN. Due to the number of similarities it is thought the petunia isolate belongs to the PVYNTN group of isolates. Out of 24 species of bedding and pot plant crops tested, 19 were shown by mechanical inoculation to be susceptible to PVY, highlighting not only a clear risk to a number of commercially important plant species from PVYNTN infected trailing petunias, but also other susceptible crops grown in these areas.