Isolation and characterization of fungi associated with wheat heads and leaf blotch symptoms in Sweden

Abstract There are 32 diseases of agronomical importance in wheat, which makes disease management in this crop of worldwide importance extremely challenging. Wheat diseases affecting the leaves and the ears are major drivers of chemical fungicides use in Sweden and worldwide. Swedish fields are regularly infested with head blight diseases caused by a complex of Fusarium and non-fusarium taxa, head molds caused by weakly pathogenic or saprophytic fungi such as Alternaria species, and leaf blotches caused by Zymoseptoria tritici , Pyrenophora tritici-repentis , and Parastagonospora nodorum . In this work, we isolated and characterized fungal taxa associated with wheat ears and leaf blotches in nation-wide survey in collaboration with the Plant Protection Extensions of the Swedish Board of Agriculture. The overall aim was to increase our understanding of the wheat disease landscape in Sweden, and create a useful collection of field isolates. Here, we analyze nearly a thousand isolates collected from wheat fields across eight counties and report the identification of pathogenic and non-pathogenic taxa associated with wheat ears and leaf blotch symptoms. We propose that such surveys are necessary and useful for supporting disease diagnostics and guiding pathogen population monitoring in Sweden.