Other reports of Ralstonia solanacearum on Pelargonium
Following the previous report of Ralstonia solanacearum race 3 biovar 2 on Pelargonium zonale imported into Germany from Kenya (see EPPO RS 2001/106), the EPPO Secretariat looked for more information and found some other incidents.
In the Netherlands, the PD Newsletter of January 2001 mentioned the occurrence of brown rot on Pelargonium. All infected plants were destroyed.
In Belgium, two firms producing Pelargonium were found infected by Ralstonia solanacarum in 2000. They had imported cuttings from the Netherlands. All suspect plants were destroyed (Annual report of the Ministry of Agriculture for 2000 on Internet).
Interestingly, there is also a report from Wisconsin (US) which mentions the identification of R. solanacearum race 3 biovar 2 on two varieties of Pelargonium in 1999. A similar bacterial isolate has also been found in South Dakota. When inoculated, the isolates from Wisconsin and South Dakota produced typical wilt symptoms to both geranium and potato plants. It is noted that previously, R. solanacearum race 1 biovar 1 was the predominant race/biovar reported on glasshouse-grown ornamentals in the USA (Williamson et al., 2001).
In 1999, losses in Pelargonium crops due to R. solanacearum were reported for the first time from Pennsylvania (US), but not data is given on the race/biovar found (NAPIS web site).
Note: It seems that the risk of moving R. solanacearum race 3 biovar 2 on host plants other than Solanaceae, and in particular on pelargonium, may need to be re-assessed.
Belgian Ministry of Agriculture Web site.
DG4 – Rapport d’activités. La Qualité des Matières premières et du Secteur Végétal. 2000.
NAPIS Web site.
Pennsylvania Plant Pest Report of 1999-05-14. Alert-Southern bacterial wilt on geraniums.
Dutch Ministry of Agriculture Web site.
Nieuwsbrief PD, no. 1, January 2001. Onderzoek naar bruinrot in Pelargonium.
Williamson, L.; Nakaho, K.; Allen, C.; Hudelson, B.; (2001) Ralstonia solanacearum race 3, biovar 2 isolated from geranium in Wisconsin.
Phytopathology, 91(6), S95.