Surveys on potato ring rot and brown rot in Finland
In Finland, systematic surveys for Clavibacter michiganensis subsp. sepedonicus (potato ring rot - EPPO A2 quarantine pest) started in the 1980s. At the beginning, only visual inspections were done, but since 1994 most inspected samples are also tested in the laboratory for latent infections. In addition, surveys are now also done for Ralstonia solanacearum (potato brown rot - EPPO A2 quarantine pest) every year on seed and ware potatoes. These surveys are carried out in the most important potato-growing areas in Finland. Results for the Finnish potato production, as well as for potato imports in 1997 and spring 1998, are the following.
- Clavibacter michiganensis subsp. sepedonicus
Sampling and laboratory testing followed the EU Directive 93/85.
Ware potato production (including industrial potatoes): In total, 1905 samples were collected, inspected and tested. After biological tests (on aubergine), C. michiganensis subsp. sepedonicus was found in 68 samples (from 42 different farms, i.e. 12 % infested farms which is similar to previous years). However, it is noted that the most important potato-growing area which is located in Northern Ostrobothnia (Pohjois-Pohjanmaa, on the west coast) is practically free from the disease. In addition, ring rot has not been found for many years in the 'high grade area', and its incidence is very low in the food industry potato production.
Seed potato production: In total, 1443 samples were tested (including pre-basic material: 78 samples), and 1081 samples were also visually inspected in seed potato farms. No ring rot was found.
Imported potatoes: during summer 1997 and spring 1998, 262 samples of ware and seed potatoes imported from EU countries were inspected and tested. C. michiganensis subsp. sepedonicus was found in 2 samples of industrial potatoes from Sweden.
- Ralstonia solanacearum
Finnish potato production: 139 ware potato samples (from 134 farms) and 60 seed potato samples (from 58 farms) were tested in the laboratory and no Ralstonia solanacearum was found.
Imported potatoes: 262 samples of imported potatoes were tested and no R. solanacearum was found.
Sources
NPPO of Finland, 1999-04.