Most potato late blight outbreaks have occurred in East Anglia this season, according to the AHDB’s Fight Against Blight report, however, there has been a surge in submission of samples from Scotland in the latter half of the season.
Up to August 19, 24 outbreaks had been recorded for East Anglia, with the aggressive EU36-A2 genotype predominating. In Scotland, 13 outbreaks had been recorded to this date. Few outbreaks had been recorded in the Midlands, North East and South West of England, says Dr David Cooke research leader at the James Hutton Institute.
“EU37-A2 [an aggressive strain] is around but at a lower level than in previous years,” says Dr Cooke.
The EU36-A2 and EU37-A2 strains are both present in Scotland now, he says. “This is a concern for Scottish growers. EU36-A2 has only been found in Fife and Angus. But the fact it has been found means it could spread across the potato growing area. EU37 has been found in two outbreaks. With this strain, advisers recommend only using fluazinam if it is mixed with other products [due to resistance].”
For growers considering flailing potatoes as the end of the season approaches, Dr Cooke advises keeping an eye on regrowth, which can become infected with blight.