Pluriannual experience in controlling fusarium head blight and the content of DON in infected kernels with de methylation inhibitors (DMI) fungicides.

Fusarium head blight (FHB) is the main worldwide wheat disease. In Emilia-Romagna region (Northern Italy), the most frequent species responsible of FHB on durum wheat were Fusarium graminearum and F. culmorum since 1995. FHB can cause losses in production (0.6-2.7 t/Ha) and seed quality, due to kernel infection and micotoxin accumulation. From 2000 to 2006, some DMI commercial fungicides were evaluated for their efficacy in controlling FHB incidence and severity, percentage of infected kernels and deoxynivalenol (DON) content in kernels. DMI were applied at anthesis stage (GS 60-61), in several cultivars of durum wheat, inoculated artificially with a mixture of F. graminearum and F. culmorum toxigenic isolates. Trials, on fourteen cultivars with bromuconazole, prochloraz and tebuconazole were performed from 2000 to 2002 and on four cultivars with epoxiconazole + prochloraz, cyproconazole + prochloraz, metconazole (not yet registered in Italy) from 2005 to 2006. These fungicides significantly reduced incidence and severity of FHB compared with the untreated control. The results showed an average efficacy in reducing the tested parameters of 53% and 68% respectively in the first experiment, 64% and 59% in the second. From 2000 to 2002 on six durum wheat cultivars, bromuconazole, prochloraz and tebuconazole significantly reduced the percentage of F. graminearum and F. culmorum infected kernels by averagely 63% and DON content of 66%, when compared with the untreated control. The knowledge of DMI efficacy in reducing FHB incidence and severity, infected kernels and DON content is very important for setting up disease control strategies.