FREDERICTON -- The group representing potato farmers on Prince Edward Island says its members need answers quickly from Ottawa on the decision to suspend all shipments of fresh potatoes from the Island to the United States or the industry will face huge financial losses.

Prince Edward Island Potato Board general manager Greg Donald says farmers were shocked to learn Monday that Agriculture Minister Marie-Claude Bibeau had ordered the trade restriction after the recent discovery of potato wart in two P.E.I. fields.

"This isn't a new issue for us," he said in an interview Tuesday. "It's something we've been managing for 20 years. The plan we have is one that has been formally accepted by the U.S."

The fungal parasite spreads through the movement of infected potatoes, soil and farm equipment. It poses no threat to human health but can greatly decrease the yield of potato crops and can leave potatoes disfigured.

Donald said rules created by the federal government have prevented any spread from the province to the U.S.

"The two detections this year were in fields already under the Canadian Food Inspection Agency's watch because of their association with past detections," he said. Donald said when the fungus is found, inspectors go back 10 years to identify neighbouring fields or those that have shared equipment.

"The potatoes weren't even going to leave the Island. When it was found, they were quarantined. We were concerned, but given the plan, we didn't think there would be any issues," he said.

Bibeau told reporters Monday the United States hadn't left Canada with much choice. "They made it clear that the U.S. would have imposed a federal order banning import of all fresh P.E.I. potatoes if Canada did not act first to suspend trade," the minister said. She said if the United States had acted first, it would have been "much more difficult to reverse."

Donald said he wants to know what changed to lead to the pressure from the Americans. He said he believes it is solely a politically based trade disruption. "The minister says she has full confidence in the science. If she says that, and we certainly believe that, then what else can it be?"

He notes that the same controls on P.E.I. potatoes going to the United States apply to Idaho potatoes shipped into Canada. "If those provisions are being questioned for fresh potatoes going to the U.S., why are they adequate for those potatoes coming to Canada from Idaho?" he asked.

In Ottawa, Opposition Conservatives say the Liberal government should be providing more information to P.E.I. potato farmers. In a statement Tuesday, they called on the federal government to release a plan to support the affected farmers and provide a date for when the ban will be lifted.

The Greater Charlottetown Area Chamber of Commerce is also criticizing the federal move. "The government of Canada must stand up for science-based decision making on this issue and ensure the border is reopened without delay," Chamber CEO Robert Godfrey wrote in a statement.

Donald said P.E.I. normally ships about $2 million worth of potatoes to the U.S. each week, adding that unless a resolution can be found quickly, losses will rise and good potatoes will be destroyed.