According to a report by The Scottish Farmer, discovery of a late blight strain less sensitive to a key fungicide in Scotland requires potato growers to apply strict resistance management principles when planning fungicide programmes this season.
Two blight strains, 37_A2 and 36_A2, are of concern to the UK potato industry and up until last year, positive samples of either genotype have been confined to England.
Last year, however, there was an unexpected discovery of 37_A2 in SRUC potato trials at the Auchincruive Estate, near Ayr, run by researcher and blight expert, Ruairidh Bain.
He told The Scottish Farmer that the trials were intensively inoculated with 13_A2, which took hold in plots almost immediately and expressed symptoms on a range of varieties.
However, at the end of season, genotype testing of leaf blight samples by David Cooke, at James Hutton Institute (JHI), revealed that 19 of 24 samples were 6_A1, two were 13_A2 and most importantly, three were 37_A2 – a strain less sensitive to fungicide active, fluazinam.