EPPO Global Database

EPPO Reporting Service no. 11 - 2003 Num. article: 2003/159

First report of Clavibacter michiganensis subsp. sepedonicus in United Kingdom

In November 2003, the presence of Clavibacter michiganensis subsp. sepedonicus (potato ring rot – EPPO A2 list) was reported for the first time in United Kingdom. During the regular official survey, the bacterium was discovered in a sample of seed potatoes (Solanum tuberosum cv. Provento) grown in one farm, in Wales. These potatoes had originally been produced from imported Dutch seed potatoes. On the farm concerned, all potato stocks grown in 2003 have been tested and two stocks associated with cv. Provento were found infected. Studies have been  done to trace all movements of related potato stocks. No other stocks on the farm tested positive. It has been found that 2 consignments of seed potatoes were exported to Islas Canarias before the infection was found. As a consequence, the Spanish authorities were informed of the possible risk of infection immediately after the results of the initial tests were known. Three farms in England had bought potatoes of a different variety from the Welsh farm, their potato stocks were tested and no other positive findings were made. Five other farms in England grew crops in 2003 with a varietal link to the infected stocks.  These stocks were also tested and no positive findings were made. It is now planned to test all stocks deriving from seed potatoes grown in 2002 on the Welsh farm. Contact has been  made with the Dutch authorities to find whether other seed potatoes of cv. Provento or produced by the same grower may have gone to United Kingdom. Eradication and containment measures are being applied against potato ring rot.
The situation of Clavibacter michiganensis subsp. sepedonicus in United Kingdom can be described as follows: Present, first found in 2003 in one seed potato farm in Wales, under eradication.


DEFRA Web site.
First finding of potato ring rot in the United Kingdom (2003-11-12).
Further precautionary action against potato ring rot (2003-11-19).
Progress made on containing potato ring rot (2003-12-09).
Finding of potato ring rot in Wales – Key points and facts