Relationship between <i>Fusarium</i> spp. diversity and mycotoxin contents of mature grains in southern Belgium

Over a 4-year period (2010–13), a survey aiming at determining the occurrence of <i>Fusarium</i> spp. and their relations to mycotoxins in mature grains took place in southern Belgium. The most prevalent species were <i>F. graminearum</i>, <i>F. avenaceum, F. poae</i> and <i>F. culmorum</i>, with large variations between years and locations. An even proportion of mating type found for <i>F. avenaceum</i>, <i>F. culmorum</i>, <i>F. cerealis</i> and <i>F. tricinctum</i> is usually a sign of ongoing sexual recombination. In contrast, an unbalanced proportion of mating type was found for <i>F. poae</i> and no <i>MAT1-2</i> allele was present in the <i>F. langsethiae</i> population. Genetic chemotyping indicates a majority of deoxynivalenol (DON)-producing strains in <i>F. culmorum</i> (78%, all 3-ADON producers) and <i>F. graminearum</i> (95%, mostly 15-ADON producers), while all <i>F. cerealis</i> strains belong to the nivalenol (NIV) chemotype. Between 2011 and 2013, DON, NIV, enniatins (ENNs) and moniliformin (MON) were found in each field in various concentrations. By comparison, beauvericin (BEA) was scarcely detected and T-2 toxin, zearalenone and α- and β-zearalenols were never detected. Principal component analysis revealed correlations of DON with <i>F. graminearum</i>, ENNs and MON with <i>F. avenaceum</i> and NIV with <i>F. culmorum</i>, <i>F. cerealis</i> and <i>F. poae</i>. BEA was associated with the presence of <i>F. tricinctum</i> and, to a lesser extent, with the presence of <i>F. poae</i>. The use of genetic chemotype data revealed that DON concentrations were mostly influenced by DON-producing strains of <i>F. graminearum</i> and <i>F. culmorum</i>, whereas the concentrations of NIV were influenced by the number of NIV-producing strains of both species added to the number of <i>F. cerealis</i> and <i>F. poae</i> strains. This study emphasises the need to pay attention to less-studied <i>Fusarium</i> spp. for future <i>Fusarium</i> head blight management strategies, as they commonly co-occur in the field and are associated with a broad spectrum of mycotoxins.