BOISE - A group of 10 eastern Idaho potato growers and a shipper have filed a lawsuit seeking to end a quarantine and field testing imposed by state and federal authorities after the discovery of a microscopic pest that led some countries to ban Idaho spuds.

The group in the lawsuit filed in U.S. District Court in Idaho last week cites the 10th Amendment concerning state's rights in arguing that the federal government is illegally imposing regulations in Idaho through the U.S. Department of Agriculture. The group also said authorities failed to follow federal environmental laws in imposing actions without proper study, such as an Environmental Impact Statement.

The lawsuit names the Idaho State Department of Agriculture as a defendant as well, contending the agency didn't comply with Idaho law in making decisions the group calls capricious.

The discovery of the pale cyst nematode in Bingham and Bonneville counties in 2006 was the first detection of the pest in the United States, and authorities have been trying to eradicate it ever since. The plan includes quarantine and treatment of infected fields as well as special regulations for some associated fields.

The U.S. Department of Agriculture said the pale cyst nematode has infested 2,897 acres in 26 fields in northern Bingham and southern Bonneville County. Another 7,423 acres are being regulated because they might also be infested.

That's a tiny fraction of the land producing potatoes in Idaho - about 320,000 acres annually. In 2013, Idaho led the nation by producing 13.6 billion pounds of potatoes valued at more than $900 million, according to the USDA's National Agricultural Statistics Service. That's about a third of the nation's potato crop.

But fields infected with the pale cyst nematode are out of the potato growing business.

"Many farmers and ranchers have worked for generations to build and develop their family farms, only to find that with the discovery of a single PCN, their entire operation is thrown into turmoil and the value of their property significantly reduced," the group said in a statement.

It's not clear how the pest arrived in Idaho. After its discovery, some countries initially closed their markets to Idaho potatoes before reopening them. Japan still refuses to import Idaho potatoes.

The worms feed at the roots of potato plants and can reduce crop production by 80 percent. Officials said the pest is not harmful to humans.

Named in the lawsuit is the U.S. Department of Agriculture's Animal and Plant Health Inspection Service.

"APHIS's ad hoc and ever-changing protocols have put, and will continue to put fields owned or farmed by Plaintiffs into a circuitous and undefined state of regulation for an undefined period of time," the lawsuit states.

The U.S. Department of Agriculture did not respond to an email from The Associated Press on Friday. The Idaho State Department of Agriculture declined to comment on Friday.

The nematode in its hardened-egg form is difficult for chemicals to penetrate, and can survive for years in the soil before the nematodes emerge when conditions are rights. So methods to kill the nematodes involve waiting for them to emerge. But farmers in the lawsuit say one chemical that's been used, Methyl Bromide, is harming livestock.

The application "has made farm crops toxic and unsellable and has caused disease and death to livestock owned by multiple Plaintiffs," the lawsuit says.

Scientists said chemicals effective on the nematodes also tend to kill everything in the soil, including organisms that are beneficial to have in the soil. So researchers have been working on an array of other methods. Those include tricking the nematode eggs into hatching when there's no food available, creating sterile forms of weeds that kill the nematodes, using a nematode eating fungi, and even creating a genetically modified potato that can itself fight off the nematode.