Effect of fungicides on Fusarium head blight, yield and deoxynivalenol accumulation in wheat inoculated under field conditions with Fusarium graminearum and Fusarium culmorum

The effect of different fungicide treatments on Fusarium head blight (FHB) development, grain yields and deoxynivalenol (DON) accumulation in wheat was evaluated after artificial inoculation under field conditions with a mixture of Fusarium graminearum and F culmorum. The trials were carried out using commercially available products on five different cultivars of soft and durum wheat (Serio, Genio, Bracco, Duilio and Orobel) in two separate experimental fields located in the North of Italy. Treatments with Tiptor® S (cyproconazole plus prochloraz) and a mixture of Horizon® 250 EW (tebuconazole) plus Amistar® 250 SC (azoxystrobin) significantly reduced the FHB disease severity (by between 25 and 77%) and DON content (by between 32 and 89%) in the grain as compared with the inoculated control. Yields (tonne ha-1) and thousand grain weight (TGW) were higher in plots subjected to fungicide treatments. Tetraconazole (Eminent® 40 EW) showed a markedly reduced effectiveness compared with the other treatments. Regression analysis showed a strong correlation of disease severity with DON levels (positive correlation) and with yields or TGW (negative correlation) for individual cultivars and locations. Fusarium graminearum, F culmorum and F poae were the species most commonly isolated from all trials, including inoculated and non-inoculated control plots.