The frequency and relative density of occurrence of Fusarium spp. was evaluated on 112 wheat grain samples from different agro-ecological localities in Slovakia. The samples were collected in 2006, 2007 and 2008 from the same farmers and from the same localities every year immediately after harvest. In 2006, contamination was 95.2%, in 2007 it was 64.3%, and 71.4% in 2008. The highest average frequency of occurrence was found in Fusarium graminearum in 2006 - 65%. The prevalence of Fusarium poae was ascertained in 2007 and 2008. The highest frequency of Fusarium spp. occurrence was revealed in locality Turčiansky Ďur in 2008 - 53.9%. The highest identified amount of Fusarium species (12) was from the area of Turčiansky Ďur in 2007. Fusarium graminearum, Fusarium sporotrichioides, Fusarium poae and Fusarium oxysporum were the most frequent in 2006, while Fusarium poae, Fusarium sporotrichioides, Fusarium graminearum and Fusarium semitectum dominated in 2007. Fusarium poae dominated in 2008, then followed Fusarium sporotrichioides, Fusarium graminearum, Fusarium oxysporum and Fusarium avenaceum. Other identified species, such as Fusarium equiseti, Fusarium tricinctum and Microdochium nivale, were in population structure in a relatively low density. Grains contaminated with Fusarium spp. are unsuitable for both human and animal consumption because of the adverse health effects of fusariotoxins.
