Relationship between Fusarium graminearum and Alternaria alternata contamination and deoxynivalenol occurrence on Argentinian durum wheat

A mycological survey was carried out on durum wheat (Triticum durum ) sampl es from the main production area of Argentina. The isolation frequency and relative density of species of dematiaceous fungi, and genus Fusarium were calculated. Alternaria alternata and Fusarium graminearum were the predomin ant fungal species. An analysis of deoxynivalenol (DON) natural contaminati on was also performed on a limited number of samples (60). DON contaminatio n levels in positive samples ranged from 26 to 6400 mu g/kg. The non-parame tric techniques applied showed that there is a positive relationship betwee n DON contamination and F. graminearum relative densities and a negative re lationship between DON contamination and A. alternata relative densities.