Evolving pathogen populations of Phytophthora infestans, the cause of potato late blight, continue to challenge integrated management practices.
Emergence of strains with increased aggressiveness or reduced fungicide sensitivity, have been observed, according to EuroBlight.
The EuroBlight network continuously examines the ongoing evolution of the European population of the potato late blight pathogen and reported on around 1500 samples collected by more than 20 partners across 16 European countries in 2017.
As in previous years, the AHDB Potatoes ‘Fight Against Blight’ campaign data from crops in Great Britain (GB) is included as well as data from partners in the IPMBlight2.0 project, which is also generating pathogen phenotype data to support IPM strategies. The combined data from 2013-2017 now comprise over 6,347 samples from 34 countries.
Over the last five years, 60-79 per cent of the population comprised known clonal lineages that recur each season. The remaining samples were novel, genetically diverse genotypes mostly found at a single location in one season and grouped in a category termed ‘Other’.
But three emerging clones - EU_37_A2, EU_36_A2 and EU_41 increased their combined frequency from 10 per cent in 2016 to 28 per cent of the population in 2017.
Over the same period, genotype 13_A2 decreased from over 30 per cent to less than 20 per cent of the population.