Situation of Clavibacter michiganensis subsp. sepedonicus in Norway
In Norway, potato ring rot (Clavibacter michiganensis subsp. sepedonicus – EPPO A2 List) was first detected in 1964, and in the following years it became evident that the disease was causing rotting of tubers and yield reduction in several Norwegian counties. Since 1965 national legislation has been implemented to control the disease and has evolved over time to become more similar to the EU Commission Directive 2006/56/EC. In 1999, the NPPO initiated an eradication programme against C. michiganensis subsp. sepedonicus in order to export potatoes to other European countries. From 1999 to 2002, a survey was conducted in commercial potato production in all counties. Potato production of all growers (with a production area ; 2 ha) was sampled and tested (IFAS, fatty acid analysis, PCR). When the bacterium was detected in a potato lot, the grower was required to implement strict eradication measures including the following: removal of infected potatoes, prohibition to use any potatoes from the infected farm as seed potatoes, disinfection of all potentially contaminated tools (handling, storage, machinery), prohibition to grow potatoes on infected land during the 2 following years, destruction of all volunteer potato plants during this 2-year quarantine period. After this initial survey, two follow-up studies were conducted (2003-2004 and 2005-2008) to monitor the effectiveness of the eradication measures. From 1999 to 2008, approximately 10;700 samples were tested from 4;433 growers across Norway. As a result, 328 cases of potato ring rot were found, mainly in the counties of Hedmark, Nordland, Troms and Trøndelag. It was also observed that the overall disease situation had improved considerably during the studied period (1999-2008), and more particularly during the period of the follow-up studies (2003-2008). The eradication programme has been re-initiated in 2011, focussing on the areas where the disease has already been detected; in addition, the quarantine period has been extended from 2 to 3 years.
Perminow JIS, Akselsen ILW, Borowksi E, Ruden Ø, Grønås W (2012) Potato ring rot in Norway: occurrence and control. Potato Research 55(3-4), 241-247.