OCCURRENCE OF CLUBROOT AND PLASMODIOPHORA-BRASSICAE WOR RACES IN FINLAND

Examination of clubroot in cruciferous vegetables in Finland in 1974-1 978 revealed the disease in 81 % of the 101 communes inspected. The di sease was most common in southern and central Finland, but was also di scovered in the northern parts of the region in which cruciferous crop s were cultivated (66-67-degrees-N. lat.). Clubroot was found in 65 % of the 375 plant samples collected. It occurred in 68 % of the samples of the most commonly cultivated vegetable, cabbage (56 % of the mater ial), in 63 % of the cauliflower samples (22 % of the material), in 56 % of the samples of other cole species (13 % of the material) and in 64 % of the samples of cruciferous root crops (10 % of the material). P. brassicae race determinations were performed on 90 samples. The cla ssification system of WILLIAMS (1966) was applied. The races that were isolated were 1, 2, 3, 4, 6 and 7. Race 2 was by far the most common, being found in 32 communes; races 3, 4, 6 and 7 were each found in 9- 12 communes; race 1 only in one commune. No clear differences in the o ccurrence of the races in the various parts of the country could be ob served. A comparison is made between Williams' and the ECD (BUCZACKI e t al. 1975) classification systems. In addition, the pathotypes in clu broot material from Norway and Iceland were determined.