Shifting von Fusarienarten und ihren Toxinen in österreichischem Getreide

Abstract

Based on representative analyses of Austrian cereals, a distinct shift in the spectrum of Fusarium toxins and Fusarium species has been observed since the middle of the eighties.

Although in the case of maizeF subglutinans — apart fromF graminearum — proved to be the most frequent and constant contaminant over the entire range of test series, there has been a shift in the spectrum of species which is not to be explained simply by seasonal variations or by the varying degree of occurrence of the European corn borer, which in Austria is considered to be the main vector for infections involving fusaria of the Liseola section. Compared to the results from earlier vegetation periods, the nineties brought a significant increase in the number of infections withF proliferatum, a fumonisin-producer. In all likelihood, this shift in the spectrum of species is due to the changed climatic conditions now prevailing in Austria — milder and more humid winters vs. drier and warmer summers — which favour the progress ofF proliferatum.

The principal toxin-forming fungus on cereals in Austria isF graminearum. On maize, its respective populations are exclusively those which produce 15-acetyl-DON as a precursor to DON (deoxynivalenol). Whilst in the 1980s,F graminearum isolates from wheat yielded both 15-acetyl-DON and 3-acetyl-DON types, only 15-acetyl-DON populations could be detected in the last few years. One possible explanation for this phenomenon is the continual intensification of maize-wheat crop rotations. In the light of the above observations, the frequently used argument whereby EuropeanF graminearum isolates produce mainly 3-acetyl-DON and American strains prevalently 15-acetyl-DON will have to be reviewed.