06 September 2022
Fight Against Blight team update.
DOCTOR David Cooke and the Fight Against Blight (FAB) team at the James Hutton Institute in the UK recently gave an update on their work to date, and thanked all the scouts who had found and submitted samples of late blight during the exceptionally warm, dry 2022 season.
The FAB mapping site is now available and shows the 37 outbreaks reported to date from across Britain (www.blight.hutton.ac.uk/BlightReport).
David said the first outbreak was reported from Cornwall in mid-March, with four more in May from Cornwall, Kent and north and south Wales. Slightly more favourable conditions for blight occurred locally in June and 13 outbreaks were reported from across England and Wales.
Despite the very dry conditions in July, another 13 outbreaks were reported and a further seven to date in August. Seven outbreaks remain unconfirmed or negative owing to either very dry lesions or sample degradation in the post. Late blight was formally confirmed in Scotland for the first time in August as prior samples were dried up.
“Genotyping of 127 samples of Phytophthora infestans from 26 outbreaks indicates over 50% are of genotype 6_A1 with almost 30% of 36_A2, 6% of 37_A2 and 9% being ‘Other’ genotypes,” said David. “The higher prevalence of 6_A1 than in 2021 (24%) is down to a higher frequency of sampled outbreaks in western than eastern potato growing regions. Genotype 36_A2 has been sampled in Kent, Cheshire, Merseyside, Norfolk, Shropshire and north Wales. The presence of 37_A2 in two outbreaks in Cheshire is a reminder of the need to follow current best practice in use of fluazinam.”
He encouraged scouts to continue to submit samples from crops and volunteer potatoes to get a full indication of the 2022 pathogen population, and to include lesions pressed onto the FTA cards to ensure genotypes can be recovered from pathogen DNA. Those who had not received a sample pack, or in need of new packs should contact [email protected].
At the time of going to press, the team at Hutton was looking at screening a selection of contemporary isolates against key fungicide active ingredients.