Unusual and severe epidemics of yellow rust were observed on several continents in 2017. In a number of cases, epidemic sites at different continents were inter-related by prevalence of genetically identical yellow rust genotypes and races. Key highlights South America: Three distinct genotypes were detected in severe yellow rust epidemics in Argentina in 2017. These genotypes have been associated with recent rust epidemics in Europe/northern Africa. Central Asia/East Africa: Region specific genotypes were prevalent in Central Asia. One of these (PstS11) was also detected in East Africa in 2016, prevalent in severe yellow rust epidemics in Ethiopia. The spread of PstS11 was