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The benefit of tracking blight genotypes

Publication Date: 
18 September 2017

Earlier this season AHDB notified growers and agronomists in our blight network about reports of the spread of the blight strain EU_37_A2 in the Netherlands (where it was first found in 2013), Germany, Belgium, and NW France. Isolates of EU_37 have shown a reduced sensitivity to Fluazinam.

Over the summer of 2017, there have been isolated findings of EU_37 that appear to be broadly centred on three areas (see table below). David Cooke of the James Hutton Institute (JHI) has been conducting AHDB funded blight genotyping work for a number of seasons and confirmed the genotype of the findings. This follows two leaf samples and six tuber samples confirmed postharvest in 2016.

Table correct at 5 September 2017 (for the latest findings please click here)

The reports served as a timely reminder for those in our blight network to follow best practice and use a range of blight treatments. This episode shows the benefits of the AHDB funded blight genotyping work and David’s links with EuroBlight.

What is EuroBlight?

EuroBlight is a European network of scientists and other specialists working on potato early and late blight. The group meet every 18 months to present and discuss recent results on integrated control of late blight (Phytophthora infestans) and early blight (Alternaria spp.). The current network evolved from two previous networks originating from European Concerted Actions and has 150 members.

EuroBlight began life in 1997 as an EU funded project. Since then the industry has since recognised the importance of the work the group undertake and sponsor their efforts. AHDB has contributed to the work of the group in various ways, including the supply of British data since 2006.

EuroBlight in Action: Genotype tracking

The group discuss the advancement of many areas pertaining to blight. The subjects discussed and the subgroups that met at the most recent meeting at Aarhus, Denmark in May 2017 included:

  • Control strategies
  • Pathogen characteristics and host resistance
  • Alternaria
  • Epidemiology and modelling
  • Host/pathogen interactions and characteristics
  • Late blight and P. infestans - importance and characteristics

David Cooke, who was chair of the host/pathogen interactions and characteristics subgroup at the above meetings, presented on this element the work of EuroBlight at Potatoes in Practice, the UK’s largest technical potato field event jointly hosted by JHI and AHDB.

Using the example from above, the spread of EU_37, the below provides a good indication of how a new strain of blight can go from a single location to an international issue in a relatively short space of time.

The Fight Against Blight

In the UK, samples that are fed into EuroBlight are collected through AHDB’s Fight Against Blight (FAB) service. The main function of FAB is to distribute geographical alerts of blight to subscribers. The service relies on ‘blight scouts’ sending in samples, which are analysed in a lab so that the confirmed reports can be distributed via email and alerts on the FAB website/app.

During a typical year, work on genotyping is completed at the end of the season. This season genotyping work has been conducted in real time, in order to assist with the identification and management of EU_37.

Knowledge Exchange Manager at AHDB Claire Hodge said: “The results from this year’s genotyping work show the majority of samples have been from genotypes we would expect see. Only 12 samples have tested positive as EU_37, the remaining 107 are more common strains.”

The new website and app did experience some teething problems for new registrants at the beginning of the season. However, the system has been working well for blight scouts and has produced useful information.

Anyone who requires any assistance with logging in should contact Claire Hodge.-

Join the fight

To register for alerts or to sign up as a scout please visit Once you have registered you can also visit the app store to download the app.

Results for all positive samples are available on-line and on the app; the identification details are anonymous and only known to the scout that sent in the sample. By working together we can increase the performance of our blight programmes. Episodes such as the above serve as a reminder of the importance of sharing samples so that we can track insensitivity and resistance across various strains.

Further reading

AHDB website:

The fight against blight website:


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