Further details on Ralstonia solanacearum biovar 2 race 3 on Pelargonium in the United States
EPPO RS 2001/124 and 2002/115 reported on findings of Ralstonia solanacearum biovar 2 race 3 (EPPO A2 quarantine pest) in the US in 1999, in Pennsylvania, Wisconsin and South Dakota. Further data is now available. In Wisconsin, R. solanacearum was isolated in spring 1999 on Pelargonium plants imported from Guatemala and grown in glasshouses. Tests were later carried out on several strains of Ralstonia solanacearum (including Pelargonium strains from Wisconsin, South Dakota and New Jersey) to determine biovar and race. Results showed that these three isolates belonged to biovar 2, race 3. Furthermore, pathogenicity tests were carried out and demonstrated that these Pelargonium strains were also highly pathogenic to potato and tomato. The authors also mention that Solanum dulcamara (weed host of R. solanacearum) occurs in north-eastern United States. They express concern about the possible movement of R. solanacearum from glasshouse-grown Pelargonium to field potatoes.
Note: the record of R. solanacearum biovar 2 race 3 in New Jersey is new for the EPPO Secretariat.
Williamson, L.; Nakaho, K.; Hudelson, B.; Allen C. (2002) Ralstonia solanacearum Race 3, Biovar 2 strains isolated from geranium are pathogenic to potato. Plant Disease, 86(9) 987, 991.