Controlling "Fusarium" species and their mycotoxins in cereals

Abstract

Fusarium head blight (FHB) is a severe fungal disease on cereals like wheat, corn and barley. It is caused by a complex of several Fusarium species producing mycotoxins. Besides having a toxigenic effect on humans and animals, mycotoxins have a high impact on grain yield and quality. Securing yield quantity and quality is important for the farmers and the control of FHB remains strategic including appropriate agricultural practices, genetic and biological measures but the predominance of monoculture still requires the application of fungicides to save the harvest. Demethylation inhibitor (DMI) fungicides and quinone inhibitor (Qol) fungicides were reported to decrease FHB. However, decreased fungicide sensitivity or full fungicide resistance has been reported to these two fungicide classes. Therefore, the new class of SDHI (succinate dehydrogenase inhibitors) fungicides has gained attractiveness, particularly those with novel chemical structures like pydiflumetofen. Aim of this study was to investigate the interaction of fungicide action and FHB disease complex in order to provide insights helping the control of the FHB complex and its mycotoxins in wheat and corn. To perform, in-vitro assays were conducted in order to test the sensitivity of more than 500 isolates representing 13 Fusarium species to different fungicide class, DMI fungicides, quinone outside inhibitor fungicides (QoI), benzimidazole fungicides (MBC), SDHIs. SDH subunits of the Fusarium panel were analyzed and greenhouse and field assays were performed to investigate the activity of fungicides in realistic conditions. Results indicate a superior efficacy of pydiflumetofen compared to all tested fungicides. The advantage was shown for all species, all isolates and all mycotoxins.