Control of Fusarium head blight of wheat with fungicides

The control of Fusarium head blight (FHB) of wheat using fungicides was investigated in two field trials. The first trial examined the effects of tebuconazole applied at a range of crop growth stages around flowering, whereas the second trial compared nil fungicide, tebuconazole, carbendazim, and azoxystrobin, applied at full ear emergence or mid anthesis. Moderate FHB levels were recorded in untreated plots in both trials. In the first trial, FHB incidence was reduced by up to 90% and yield increased by 14% following two applications of tebuconazole. Levels of Fusarium in harvested grain were not affected but mycotoxin levels were reduced by some treatments. In the second trial FHB incidence was decreased and grain weight increased with all fungicides at one or both application stages. High levels of Fusarium were recorded in harvested grain in the nil fungicide treatment. Levels of both Fusarium and resulting mycotoxins were substantially reduced following treatment with tebuconazole or carbendazim but were not affected by treatment with azoxystrobin. Fusarium graminearum Schwabe predominated in both trials, although eight species of Fusarium were identified in each trial. Although reductions in FHB and mycotoxin levels can be achieved with some fungicides, combining them with cultivar resistance is likely to provide improved control.