Associations between Fusarium species and mycotoxins in oats and spring wheat from farmers fields in Norway over a six-year period

During the last ten years, Norwegian cereal grain industry has experienced large challenges due to Fusarium spp.and Fusarium mycotoxin contamination of small-grained cereals. To prevent severely contaminated grain lotsfrom entering the grain supply chain, it is important to establish surveys for the most prevalent Fusarium spp. andmycotoxins. The objective of our study was to quantify and calculate the associations between Fusarium spp. andmycotoxins prevalent in oats and spring wheat. In a 6-year period from 2004-2009, 178 grain samples of springwheat and 289 samples of oats were collected from farmers fields in South East Norway. The grains were analysedfor 18 different Fusarium-mycotoxins by liquid chromatography mass spectrometry. Generally, the medianmycotoxin levels were higher than reported in Norwegian studies covering previous years. The DNA content ofFusarium graminearum, Fusarium culmorum, Fusarium langsethiae, Fusarium poae and Fusarium avenaceumwere determined by quantitative PCR. We identified F. graminearum as the main deoxynivalenol (DON) producerin oats and spring wheat, and F. langsethiae as the main HT-2 and T-2-toxins producer in oats. No association wasobserved between quantity of F. graminearum DNA and quantity of F. langsethiae DNA nor for their respectivemycotoxins, in oats. F. avenaceum was one of the most prevalent Fusarium species in both oats and spring wheat.The following ranking of Fusarium species was made based on the DNA concentrations of the Fusarium spp.analysed in this survey (from high to low): F. graminearum = F. langsethiae = F. avenaceum > F. poae > F. culmorum(oats); F. graminearum = F. avenaceum > F. culmorum > F. poae = F. langsethiae (spring wheat). Our results are inagreement with recently published data indicating a shift in the relative prevalence of Fusarium species towardsmore F. graminearum versus F. culmorum in Norwegian oats and spring wheat.