SCOTLAND’S TOP world standing for producing clean, disease-free potato seed is being jeopardised by imports of diseased seed.

That was the stark warning issued at Potatoes in Practice by bacteriologist Dr Gerry Saddler of SASA, the Scottish government division responsible for plant health, who urged growers to rely solely on Scottish seed rather than imported seed which carries an increased risk of disease, in particular the new Dickeya Solani pathogen which is causing major disruption in some European countries.

“In the last five years, Dickeya has become the predominant cause of blackleg in some European countries and while it has never been found in Scottish potatoes from Scottish seed, it has been found in four separate locations in Scotland, all of which originated from imported seed,” he said.

“We are the only country in the world doing anything about Dickeya, which, because it’s not a quarantine disease, is widespread in Europe. Scotland has a zero tolerance for Dickeya and it is now illegal to plant potatoes with Dickeya.”

Worse still, he warned that growers found to have Dickeya, Brown Rot, or Ring Rot in their crops could be wiped out of business.

“These crops have to be destroyed, and all linked machinery has to be completely disinfected with the producer having to pay for all costs which could potentially devastate businesses. Fields with Dickeya cannot grow potatoes for the next two years.”

Instead, he advised the industry to take increased measures to improve hygiene levels to ensure the country remains free of disease.

“Brown Rot and Ring Rot have not been eradicated but they are at a manageable level and up to farmers to control. Ring Rot has not be found in the UK for the past five years but it is of major concern to the UK as it can survive on the side of stores for up to 18 years and Dickeya can move via potato boxes moving from north to south for processing.

“There has been three positive findings of Brown Rot in England and Wales in recent years, but all have been linked to Dutch seed. Hygiene is a major issue and not a waste of time,” he stressed.

Adding to the problems, is the fact that while Dickeya spreads via tubers, Dr Saddler pointed out that contamination of irrigation water is also a likely, albeit unproven source.

Disease risks are further increased by the fact that the industry has been rationalised to such an extent, that sub-contractors such as sprayer operators readily move between fields while some growers not only process and grade their own potatoes, they also provide the same service to other producers.

Consequently, Dr Saddler urged producers to stick to the principals of the Potato Council’s Safe Haven Scheme, by relying solely on Scottish seed, while also applying strict separation of seed and ware potatoes. Growers, he said, should not move from ware to seed potatoes, and that they should ensure all machinery is completely disinfected between crops.

Commenting on the use of potato boxes he said: “Wood is almost impossible to disinfect properly therefore my advice would be if boxes have been away from the farm for a period they should not be taken back. I know how much they cost and that it is difficult – non-returnable big bags might be the answer.”