Ring rot discovery poses threat to potato industry

A potentially catastrophic potato disease has been discovered in the United Kingdom for the first time.

A potentially catastrophic potato disease has been discovered in the United Kingdom for the first time.

Ring rot, which can cut potato harvests by half, was detected at a Welsh farm that supplies seed potatoes to many other farms in Britain and abroad.

The disease, a virulent bacterial infection that rots potatoes from within, is found in the United States, the former Soviet Union and parts of Eastern Europe. It has become established recently in a number of European Union member states, including France, Germany, the Netherlands, Denmark, Greece, Spain and Finland.

The disease was discovered during a routine check at Middlewood farm near Bwlch in Powys. The afflicted potatoes had been grown from seed potatoes imported from the Netherlands.

Scientists and officials from the Department for Environment, Food and Rural Affairs (Defra) have activated an emergency plan to trace all movements of the infected stock.

Last night Malcolm Thomas, director of NFU Cymru, the Welsh affiliate of the National Farmers' Union, speaking from the farm, said there had been only two shipments of the potatoes, both to the Canary Islands in the past two weeks, and both had been traced.

Government sources said privately that a repeat of an epidemic on the scale of the disastrous foot-and-mouth outbreak in 2001 was thought unlikely, and it was hoped that the ring rot outbreak had been caught before it could spread.

"It's a serious infectious disease, but at the moment we are concentrating on the one farm, and we think it has not got beyond that farm," said Dr Stephen Hunter, Defra's head of plant health.

"If we had a widespread outbreak it would impact on the industry very seriously. The way things are looking at the moment, it will be a few days before we can be sure that we are clear, but we are increasingly optimistic."

The British potato industry produces nearly 6 million tons of potatoes annually, worth £3.6bn. About 4,300 medium and large-size farming businesses are involved, as are about 1,000 dealers and wholesalers. Helen Priestley, chief executive of the British Potato Council, the industry umbrella body, said there would be no threat to potato supplies, and stressed that ring rot posed no threat whatsoever to human health, a fact that was also confirmed by Defra.

The only victim so far is John Morgan, the owner of Middlewood farm, who will be forced to destroy his potato stock, worth several hundred thousand pounds, with little prospect of compensation, because no compensation scheme for ring rot exists.

Mr Morgan was a responsible and widely respected grower who was feeling "absolutely devastated", Mr Thomas said.

"He faces losing everything, and we will be talking to the Government about possible compensation as a matter of urgency."

Ring rot, caused by the bacterium Clavibacter michiganensis, is one of two serious bacterial diseases of potato not yet established in Britain, the other being brown rot.

The main yield loss caused by both is through rotting of tubers. In the United States, annual losses from ring rot have been as high as 50 per cent, while brown rot is the main limiting factor in potato production in many parts of the world.

If either were to become established in Britain, not only would the nation's potato industry suffer direct yield losses but the knock-on effect on the seed potato industry could be substantial, especially for exports, which stand at 46,000 tons per year.

Once the potato diseases are established, the cost of controlling them can be extremely high.

Defra warns: "Control of these diseases requires vigilance from all sectors of the industry, from growers through to merchants, packers and retailers."