[Fusarium species - causes of the dry rot of potato in Slovenia [area, stored products, Yugoslavia]]

This paper gives some results of investigating and identifying species of the pathogenic fungus Fusarium spp. of potato, spread at the territory of SR Slovenia (SFRY) and susceptibility or resistance of some potato varieties. The fungi were isolated by standard laboratory methods from 25 naturally infected potato samples taken from several parts of SR Slovenia. The potato dextrose agar was used as a nutrient. The following potato varieties were used for the experiment:Desiree', Saskia, Resy, Bintje, Jaerla and Sirtema. The following species of the Fusarium genus were isolated:F. solani, F. sombucinum, F. avenaceum, F. graminearum and F. lateritium. Under laboratory conditions, the most pathogenic species in potato varieties Jaerla and Sirtema was F. avenaceum, and in Bintje, F. graminearum shows the highest pathogenicity index. Bintje was the most susceptible variety. Under normal storing conditions the most pathogenous species in all 3 varieties was F. avenaceum, followed by F. graminearum, F. sombucinum and F. solani. Pathogenicity of the F. lateritium species is higher than that of F. sombucinum in all varieties except Bintje, in which the average index was higher for F. sombucinum species. The 5 investigated varieties were physiologically resistant to F. sombucinum species and only Bintje was more resistant to F. lateritium. Physiologically the most susceptible potato variety was Bintje, then Resy, Jaerla, Desiree', Sirtema, while Saskia was the most resistant. The most resistant species was F. avenaceum and the least resistant F. solani. The most frequently found was F. sombucinum (41.7%). It is concluded that the dry rot of potato is becoming a more and more important disease in SR Slovenia with the expansion of mechanized production, storing and finishing in warehouses and with the import of seed potato (pathogenic fungus with the seed too).