A J.R. Simplot Co. spokesman said a national quarantine of seed potatoes from eastern Canada could cost Idaho's potato industry $50 million.

The company, which bought 200,000 sacks of the seed, is trying to get the quarantine lifted."We're anxious to see that situation resolved," company spokesman Fred Zerza said. "We doubt that this seed is contaminated."

But if the seed is contaminated and is allowed to be planted in Idaho, the state's most famous crop could lose popularity.

"Other states might be a lot more reluctant to let Idaho potatoes come in," said Roger Pollard, officer in charge at the U.S. Department of Agriculture's Twin Falls office.

Zerza said Simplot had purchased the Shepody variety of seed potatoes from Prince Edward Island and New Brunswick for distribution to Idaho farmers this spring.

When the quarantine was announced last week, the USDA said that the necrotic strain of potato virus Y had been found in potatoes grown in those provinces.

Greg Nelson, director of the Idaho Agriculture Department, told the Senate Agricultural Affairs Committee last week that several sacks of the seed spuds are already in Idaho. The virus can infect most potato varieties, but it does little damage to potatoes.

But spuds carried to other states could infect other crops in the potato family such as tomatoes, peppers and tobacco.

California and other states that grow those crops might not want contaminated Idaho spuds to cross their borders, Pollard said.

Zerza said the seed potatoes were quarantined because the USDA did not approve of Canada's disease testing methods.

"If further investigation shows the seed to be contaminated, Simplot would not want the seed," he said.

Shepody potatoes mature earlier than other varieties. They are used primarily for processing into french fries, not for fresh sales to grocers and restaurants. Zerza said the Shepody seed is important to Simplot's operations because the early maturing variety would allow the company to begin processing earlier than usual this year.

Record amounts of potatoes remain in storage this year after processors and potato growers failed to agree last summer on a contract price.

Those potatoes would be less desirable for processing next August than new-crop Shepody potatoes would be, Zerza said.

He said the company might not have known that such a glut of potatoes would remain when it ordered the Shepody seed. And he said despite advances in potato storage technology, potatoes lose quality after being stored for nearly a year.

Universal Frozen Foods does not buy seed potatoes for its growers and does not use large amounts of Shepody potatoes, field manager John Milton said. Spokesmen for Lamb-Weston and Ore-Ida Foods could not be reached for comment.