Using genetic analysis techniques similar to those employed in forensic science, plant scientists from the EuroBlight consortium, working with industry and research partners, have collated information from 795 samples collected from 25 European countries last year.
The results can now be seen on the interactive EuroBlight website.
JHI researcher Dr David Cooke said: "Although we are now better equipped to control late blight than in the past, an evolving pathogen population continues to challenge our management practices.
"Constant monitoring of populations and characterisation of invasive genotypes is essential for the deployment of integrated pest management strategies as required by EU regulations."
In a separate development, an international consortium of which JHI is also part has used cutting-edge techniques to track down the origins of P. infestans to a highland valley in central Mexico.
Cooke said: "The study has significant implications as we try to understand how hosts co-evolve with pathogens, and how to harness plant disease resistance to manage late blight."
The pathogen had previously been assumed to have arisen in the Andes mountains of South America.
The findings are published in the Proceedings of the National Academy of Sciences.