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AHDB revitalises blight tool kit

Publication Date: 
23 May 2017

Late blight, caused by the pathogen Phytophthora infestans, remains the single most important disease for the British potato trade. Spreading quickly in the foliage, a typical blight pressure season can cost the industry approximately £55 million a year in a business as usual scenario.

Understanding UK outbreaks

With such a significant impact on the industry, it’s important to respond quickly and raise awareness of the risk associated with its changing strains. As a part of its research into blight populations, AHDB Potatoes’ highly successful Fight Against Blight campaign has been redeveloped and modernised to capture more UK blight outbreaks than ever before.

Fight Against Blight, which started in 2006, is a sampling service which notifies the industry of outbreaks and risk throughout Great Britain.

Anonymous samples are collected from around the country by a team of volunteer Blight Scouts and sent to FERA (Food and Environment Research Agency) for initial tests. All positive results are then sent to the James Hutton Institute for detailed analysis.

Claire Hodge, Knowledge Exchange Manager for AHDB Potatoes, said: “The campaign has been highly successful in monitoring the pathogen population and how we compare in terms of strains to other parts of Europe.

“However, blight as a disease changes from season to season and it’s up to us to keep researching in order to combat those changes.

“Advances in technology help us to do that, and the introduction of our new website will make it easier than ever to report outbreaks and stamp out blight at the earliest opportunity.”

She added: “Growers should check whether their agronomist or key staff are part of the Blight Scout network and that their crops are being effectively scouted.”

Graeme Skinner, Agronomist at Provenance Potatoes, is a volunteer Blight Scout for the Kent region. Graeme said  “I have been a Blight Scout since the FAB campaign began, more for the greater good than anything else. If I’m capturing outbreaks in my area through sampling, this in turn will create a greater understanding of the pathogen.”

“With blight control you are making decisions before things happen, so it’s always good to stay ahead of the game. You make decisions based on many factors including the area, the weather and obviously your own experience etc, and the range of tools available helps you come to a more informed decision.”

Graeme continued, “The process of submitting samples is very easy. I just keep the packs at hand, so when I find a sample I can log it and send it off, it literally takes five or ten minutes.”

Anyone who would like to volunteer as an AHDB Blight Scout can do so by visiting the new website and registering their details.

The Hutton Criteria - AHDB Blightwatch update

Another area of significant change is the introduction of the Hutton Criteria, which is Identified by weather in order to forecast periods where crops will be more susceptible to blight, A Hutton Criteria occurs when two consecutive days with a minimum temperature of 10°C, and at least six hours of relative humidity (90%).

Arising from research funded by AHDB Potatoes and undertaken by the James Hutton Institute, the Hutton Criteria is a significant advancement on the 60-year old Smith eriod that used wider ranges of temperature and longer periods of humidity

The new criteria has been built in to will improve the reliability and reach of blight risk reporting in time for the 2017 blight pressure season. The new systems will now work with the new criteria in order to help to support decisions, refine action plans and re-empower growers against blight.

In order to allow agronomist and growers to manage risk in crops and reduce the spread of blight, AHDB’s Blightwatch service will send weather-based alerts and forecasting, based on Hutton criteria, which you can sign up to by visiting

Claire Hodge, said: “The Smith Period has been immensely valuable in assessing blight risk to date But the introduction of these new criteria, along with our own advances in technology, means we are looking to once again improve on previous results.”

Visit or follow @AHDB_Potatoes for the latest updates.

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