Besides the already known pathogen of the sugar beet damping-off, Alternaria tenuis Nees, four other species of the genus Alternaria are involved in this disease: Alternaria tenuissima (Kunze ex Pers.) Wiltshire, Alternaria dendritica (de S. da Cam.) Joly, Alternaria harzii Joly, and Alternaria chartarum Preuss. Sugar beet seeds were colonized only by A. tenuissima and A. tenuis. In the rhizosphere soil of sugar beet, A. tenuissima and A. tenuis were predominant. The species A. dendritica, A. harzii and A. chartarum were represented to a lesser extent than the two previous species. In open soil, only A. tenuis and A. tenuissima were found. In contrast to the rhizosphere soil, only a small number of colonies could be obtained from the open soil. From plants affected by damping-off, the species A. tenuissima, A. tenuis, A. dendritica and A. harzii were isolated. Pathogenicity tests have shown that these species are only weakly pathogenic to germinating sugar beet.
Veselý D. (1977): Pilze der Gattung Alternaria Nees ex Wallr., die am Wurzelbrand der Zuckerruben beteiligt sind. – Česká Mykologie 31(2): 100–107.
