Fusarium species infecting winter wheat heads in Piedmont, and the role of some agro-techniques on grain mycotoxin contamination

The contamination of winter wheat grains by Fusarium mycotoxins is threatening the quality of the wheat yielded in north-west of Italy, mainly in the years with rainy spring. In 2007-2008 in a typical cereal area of Piedmont, we investigated both on the Fusarium species involved in the disease and the effects of different crop managing on Fusarium head blight (FHB) and mycotoxin contamination of grains. Fusarium species were isolated by plating 100 disinfected wheat grains per treatment on Komada’s Fusarium selective medium, and classified both by their morphological traits and PCR analysis. Deoxynivalenol (DON) was determined by the ELISA method. Fusarium grain infections ranged 0-3.8% in 2007 and 32-92% in 2008 depending on wheat cultivar, soil cultivation and fungicide treatments, and were caused mainly by F. graminearum (97.05%), F. avenaceum (1.55%), F. poae (0.54%). DON contamination ranged 75-140 ppb in 2007 and 8,560-17,429 ppb in 2008. Direct sowing significantly promoted the disease in comparison with soil ploughing (76,7 and 52.2 % of infected grains respectively) and significant positive interactions were observed on yield weight, test weight, and reduction of DON contamination, between soil ploughing, reaction of wheat cultivar to Fusarium infections, and fungicide treatments. Among the tested fungicides, Metconazole was the most effective in reducing FHB and DON, by about 51%. DON contamination was directly correlated with the percentage of infected grains (R2= 0.7845).