Earlier this spring AHDB in the UK produced comprehensive new guidance on controlling late blight in light of the increase in the aggressive blight strain 37_A2. CPM takes a closer look. There’s been much talk about blight programmes since the 37_A2 late blight genotype emerged in the UK. It’s of particular significance because the new strain appears to be aggressive, highlighted by its relatively rapid increase in the blight population last season (from 3 to 24% of samples tested). As well as its ability to compete with rival blight strains, 37_A2 has a reduced sensitivity to fluazinam, which played a part in some of the problems experienced with tuber blight.
It’s impossible to predict the likely prevalence of 37_A2 this season, but it’s a widely held belief that it’s likely to increase. ADHB has responded to the challenges presented by 37_A2 by producing extensive guidance to the industry, co-written by SRUC’s Dr Ruairidh Bain and ADAS’ Dr Neil Paveley and Dr Faye Ritchie. One of the key recommendations is to focus on resistance management rather than just the efficacy of blight products alone, explains Ruairidh. Read more