(Note on correction: The original article incorrectly said PCN had been detected in Canada.)

The U.S. Department of Agriculture will conduct a 5-year review of its program to eradicate potato cyst nematode from Idaho potato fields.

USDA’s Plant Protection and Quarantine division will do the review later this winter, according to an agency news release.

First discovered in Idaho in 2006, potato cyst nematodes pose no danger to humans but can dramatically reduce yields if left untreated. They can, however, take up to 20 years to cause significant damage.

Twelve Idaho fields have tested positive for the pests, the most recent being Sept. 6 in Bonneville County. All 12 fields are within a 3.5-mile radius in northern Bingham and southern Bonneville counties.

More than 335,400 soil samples have been taken in Idaho to check for the nematodes. The Plant Protection and Quarantine division has used methyl bromide and chloropicrin to treat fields infected with the pests. Two infested fields were found to be free of the nematodes on follow-up tests.

Potatoes cannot ship from infested fields. Potato cyst nematodes are common in the Netherlands but they have not been found in any other U.S. state.

The 5-year program review will include a listening session with growers, a technical working group review of eradication efforts and a meeting between USDA, Idaho and Idaho Potato Commission officials.