New guidance on how the potato industry should respond to low fungicide sensitivity in late blight populations has been revealed.
Research was prompted by the prevalence of a strain of potato blight pathogen called genotype EU_37, which has proven less sensitive to the common fungicide fluazinam than other established strains in the UK.
In July last year, AHDB notified its blight network about reports of the spread of EU_37, a strain of blight first discovered in the Netherlands in 2013.
In response, Scotland’s Rural College (SRUC) worked alongside ADAS in an AHDB-funded project to develop guidance on the management of blight.
Claire Hodge, knowledge exchange manager for AHDB, said: “The dominance of the EU_37 genotype increased substantially between 2016 and 2017.
“In that time, the percentage of EU_37 samples collected by Blight Scouts who volunteer as part of our Fight Against Blight programme rose from three per cent to 24 per cent.
“If the frequency of EU_37 continues to increase, the efficacy of fluazinam is likely to be affected further.”
Evidence suggests that EU_37 has decreased sensitivity to fluazinam and comparable aggressiveness to another dominant genotype in Britain, 6_A1.
Currently there are blight fungicide active ingredients with 13 different modes of action available in the UK, therefore resistance to fluazinam should not be a major issue for potato production, provided there is sufficient diversity in the use of active ingredients.
As part of AHDB’s continued research in to blight populations, the Fight Against Blight campaign has been supplying a sampling service, which notifies the industry of outbreaks and risk.
In the 2017 season, 275 registered volunteers captured 158 confirmed samples through the service.
