Potato Review

26 POTATO REVIEW MARCH/APRIL 2023 BLIGHT R EPORTS of a single strain blight pathogen in Denmark, where some samples were shown to be resistant to the highly important CAA group of blight fungicides, has reinforced advice for growers and agronomists to prevent it occurring in the UK. e strain, EU_43_A1, had been identi ed in Denmark for the past four seasons, but never identi ed among the multitude of blight clones that make up the population in the UK. Research has shown that not all EU_43_A1 are resistant to the CAA fungicide group, however ve outlier isolates inDenmark had been identi ed as resistant last season. Sensitivitymonitoring programmes of the anti-resistance action group (FRAC) in 2022 showed ‘generally a full sensitive picture for CAAs over Europe, with a few suspicious isolates under further investigation’. European research has shown that the gene mutation associated with CAA resistance is only observed in homozygous strains of pathogens, and is therefore a recessive trait in any sexual reproduction creation of new blight clones – which signi cantly reduces the risk of further resistant strains developing. In previous reports, the James Hutton Institute has highlighted how di cult it is for blight pathogens to make the transition to the UK against prevailing winds. Resistant strain in Denmark sparks warning for UK. Protect blight fungicide e cacy Eric Anderson, Senior Agronomist, Scottish Agronomy. Andy Cunningham, Technical Manager, Syngenta. Revus gives season long protection of clean potato leaves.