Update on the situation of potato bacteria in United Kingdom
The NPPO of United Kingdom has informed the EPPO Secretariat about recent phytosanitary incidents concerning potato bacteria.
Clavibacter michiganensis subsp. sepedonicus (EPPO A2 list)
As reported in EPPO RS 2003/159, the presence of potato ring rot was discovered in November 2003 in a sample of seed potatoes (Solanum tuberosum cv. Provento) grown in one farm in Wales. In 2004, tracing and testing studies confirmed that the outbreak has been contained and that no other farms have grown or received infected stocks. In total, more than 165,000 potato tubers have been tested. On the outbreak farm, one stock of cv. Provento and one stock of a Provento/Almera admixture were found to be infected. Apart from these two stocks, all tests were negative, including for the remaining twenty other seed potato stocks on the outbreak farm. The testing programme included: all potato stocks on the outbreak farm; other stocks of cvs. Provento and Almera from the UK 2003 harvest; seed potatoes from the UK 2003 harvest grown from 2002 stock from the outbreak farm; seed potatoes from stocks with a clonal link to stocks grown on the outbreak farm in previous years; seed potatoes on farms with a machinery link to the outbreak farm. A substantial testing programme was also carried out in the Netherlands, where the Provento seed potatoes grown on the outbreak farm originated. The NPPO of UK considers that the outbreak has now been contained. However, some restrictions will remain in place (e.g. disposal of infected or possibly infected stocks, cropping restrictions on the land where the infected potatoes where grown).
The situation of C. michiganensis subsp. sepedonicus in United Kingdom can be described as follows: Transient, one isolated outbreak was detected in 2003 in one farm but was contained in 2004, still under official control.
Ralstonia solanacearum (EPPO A2 list)
In 2004, during routine annual survey, a consignment of seed potatoes was found to be infected with brown rot (caused by R. solanacearum). These potatoes (cv. Premiere) were located at one farm in Lancashire (northwest England) and were due to be planted for ware potato production. They had been imported from the Netherlands in 2003. Tracing studies showed that 3 other consignments of cv. Premiere had been delivered to 3 farms in England and Wales, as well as consignments of cv. Wilja originating from the same Dutch supplier. However, all potatoes cv. Wilja tested negative. Phytosanitary measures are being taken on the farms concerned (for cv. Premiere which is considered as contaminated and also on cv. Wilja
as a precautionary measure). These measures include: holding and disposal of seed potatoes in a manner to eliminate any risk of spread, disinfection of premises and equipment. In UK, surveys on solanaceous crops and weeds, and on watercourses are continuing.
The situation of R. solanacearum in United Kingdom can be described as follows: Present, the bacterium has been eradicated from solanaceous crops, but can still be detected in a few watercourses.
Sources
NPPO of United Kingdom, 2004-03.