Surveys on Ralstonia solanacearum in Slovenia
Since 1996, systematic surveys for Ralstonia solanacearum (EPPO A2 quarantine pest) have been carried out in Slovenia on both imported and domestic potatoes (seed and ware potatoes). From 1996 to 1999, 858 samples were tested and R. solanacearum was detected only in 4 consignments of imported early ware potatoes. In 2000, 647 samples were tested (277 samples of imported potatoes and 190 samples of domestic seed and ware potatoes). As a result, in December 2000, 1 sample of domestic ware potatoes was confirmed as being latently infected by R. solanacearum (tested tubers showed no symptoms). This sample had been collected in the northern part of Slovenia from stored ware potatoes originating from imported basic seed potatoes. Investigations were carried out to locate growers who had used potatoes from the same lot of imported seed potatoes. Some of the growers who had planted these seed potatoes for ware potato production were located. Investigations also showed that there was only one producer who had planted the potatoes concerned for of seed potato production, and that this has led to the production of 6 tons of certified seed potatoes in 2000. Additional tests were carried out to determine the extent of the disease and the results were all negative. However, according to the Slovenian legislation which is harmonized with the EU Directive 98/57/EC, eradication measures were taken. The 6 tons of seed potatoes multiplied from the imported lot concerned and 106 tons of other cultivars which were stored in the same storehouse as ware potatoes were destroyed. Storehouses, machinery and packaging material were disinfected. In fields where the imported seed lot was planted, production of potato, tomato, Brassica and other host plants of R. solanacearum was prohibited for the next 4 years, and elimination of volunteer plants and weed hosts was ordered. In 4 years time, for the first officially authorized potato-growing season, only ware production will be permitted using certified seed potatoes. In 2001, the survey will continue with special emphasis on fields which had been planted with the imported lot concerned and their surroundings.
NPPO of Slovenia, 2001-05