Fusaria and mycotoxins in wheat – monitoring of harvest samples from growers`field

In a 2-year investigation, harvest samples from Swiss growers’ wheat fields were examined for Fusarium species incidence and data on cultivation techniques were collected. In addition, the content of the mycotoxin deoxynivalenol (DON) was analysed in three quarters of the samples. From a total of 248 samples originating from 16 cantons, three Fusarium species were dominant: F. graminearum, followed by F. poae and F. avenaceum. The average DON content, produced mainly by F. graminearum, was 1.0 ppm and thus barely below the maximum limit for unprocessed cereals (1.25 ppm). However, with the pre-crop maize and reduced or zero tillage, the average DON content was 3.2 ppm. The Fusarium incidence and the DON content differed between the two years, which could be explained by the prevailing weather conditions during and after wheat anthesis. The incidence of F. poae and F. avenaceum suggests that some wheat batches could contain the toxins nivalenol or moniliformin. By collecting data on cultivation techniques on a long-term basis, we aim to elucidate factors that influence infection by the most prevalent Fusarium species on wheat. This should allow us to develop means to reduce the risk of mycotoxin contamination.