DEFRA is investigating the cause of potato brown rot found on a Nottinghamshire farm.
The disease was confirmed on Monday (21 Nov) in the Lady Rosetta variety.
The disease was detected by officials from the Plant Health and Seeds Inspectorate as part of the routine monitoring programme for ring rot and brown rot.
Later tests at the Central Science Laboratory using three separate methods confirmed the disease.
A tomato plant test, as required under EC legislation, has now confirmed the result.
Iain Dykes, seed and export manager at the British Potato Council, highlighted the seriousness of the issue: “We should be concerned.
Any outbreak of a quarantine disease is concerning.”
He is urging growers to think hard before growing potatoes near infected watercourses because of the disease risks.
“DEFRA has been working very hard to clean the river banks of woody nightshade [a host plant of the organism], but it’s very expensive and very hard to keep out,” he added.
“In some areas, DEFRA has resorted to irrigation bans.”
NFU potato spokesman Graham Nichols said it was vital to find out where the disease had come from.
“As far as I’m concerned, establishing where the disease came from is most important at this point.
It’s a fairly easy process and I understand DEFRA is carrying out some tests to identify the source.”
According to Mr Nichols, the farmer concerned was using treated water for his irrigation, but he stressed that other sources should not be ruled out.
“The farmer was treating water from an infected source – which is permissible under DEFRA rules – but we need to know if this process failed,” he added.
A DEFRA spokesperson said infected water was believed to be the probable source because of an infestation of woody nightshade on the banks of the rivers of the Midlands, but other possible causes were not being discounted.
The last outbreak of brown rot was on a farm near Corby, Northants, in December 1999.