EuroBlight issues report with details on the 2019 late blight monitoring results

EuroBlight is a European network of scientists and other specialists working on potato early and late blight and meet every 18 months. The network has 150 members. EuroBlight Coordinators are Alison Lees, The James Hutton Institute (UK), Jens G. Hansen, Aarhus University (DK), and Huub Schepers, Wageningen University (NL).

EuroBlight is continuously examining the ongoing evolution of the European population of the potato late blight pathogen and now reports on the 2019 results. Approximately 1800 samples from 27 countries were genotyped.

In general, blight pressure is said to have been low which reduced sample numbers in many regions. However, episodes of high disease pressure resulted in serious outbreaks in other areas such as northern Britain and Denmark.

With contributions from 17 groups, 1816 samples were genotyped from 27 countries. Around 75% of the samples belonged to defined clonal lineages observed in previous seasons. Some clones are widespread and have been present in Europe for more than a decade, but three more recent clones (37_A2, 36_A2 and 41_A2) increased their combined frequency from 10% in 2016 to 40% of the population in 2019.

These more recent clones are displacing the established 13_A2, 6_A1 and 1_A1 clones which reduced from 60 to 30% of the samples over the same period. A quarter of the population comprised ephemeral, genetically diverse isolates consistent with oospore-borne inoculum.

A regional pattern in the dominance of clones versus sexual recombinants was observed across Europe. Some implications of these displacements and ongoing changes are discussed in the Euroblight report.

EuroBlight reports that for the first time since 2013, the clonal lineage EU_13_A2 (blue-13) was not the most frequently sampled and dropped to 9.3% of the samples. Although in decline, this widespread, metalaxyl-resistant clone continues to affect management efficacy in Europe, parts of Asia and North Africa, reinforcing the need for pathogen data to support IPM best practices.

The frequency of EU_6_A1 rose to 20.4% due to severe outbreaks in parts of Britain where it remains dominant. The frequency of EU_1_A1 further decreased from 1.6 to 0.4% of the population. A progressive displacement of these three lineages is occurring.

The Genotype Map below can be viewed as a live map here.
The EuroBligtht report can be accessed here as a pdf file. Information is also available here.
EuroBlight maintains a website here.


Author: Lukie Pieterse