Over the years, agriculture across the world has been compromised by a succession of devastating epidemics caused by evolving viruses that spilled over from reservoir species or by new variants of classic viruses that acquired new virulence factors or changed their epidemiological patterns. Population genetics can be used as a powerful tool for identification of disease dynamics over population across large-scale geographic regions. Knowledge of life-history and origin of pathogen can greatly benefit from emergence and expansion of spatial genetics. This branch of genetics uses information of pathogen divergence at the spatial level to gain insights into a pathogen niche and evolution and to characterize pathogen dispersal within and between host populations. The assessment of pathogen transmission across different geographical region, and specifically the evaluation at long-distance dispersal events, has major significance for disease management strategies. | The evolution and emergence of plant viruses past present and future