(Oct. 15) While Canada continues to check whether U.S. states it accused of having mop top-infected potatoes actually have them, the U.S. is taking matters into its own hands.

On Oct. 9, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service announced plans to conduct its own nationwide survey of mop top, to be completed by the end of the year.

“We will now be able to determine the prevalence of mop top in the United States,” said Hollee Stubblebine, a spokeswoman for the National Potato Council, Washington, D.C., which has worked closely with APHIS ever since mop top was found on a Maine farm in August.

Under the terms of the survey, each of the 17 U.S. states that produce certified seed potatoes will test about 3,000 tubers for mop top. Stubblebine said the work could be conducted by seed certification offices in the affected states, though procedural details are still being ironed out. The tests will be paid for through an NPC grant and APHIS funds, and Stubblebine expressed hope that growers and local officials performing the tests would be compensated.

While Stubblebine said the survey was not created because of doubts over the Canadian results, the U.S. study, depending on its results, could be used as trade leverage with Canada and other countries. The U.S. also is encouraging Canada to conduct its own national survey to determine the presence of mop top in Canadian potatoes.

Initially, Canada banned potato exports from 11 U.S. states, including Idaho and Washington. But in late September, three states — California, Delaware and New Jersey — were dropped from the list, following a Canadian traceback program aimed at verifying Canada’s initial findings. Alain Boucher, a spokesman for the Canadian Food Inspection Agency, said potatoes thought to have been grown in those three states may instead only have been packed in them.

As a result of the ban on U.S. potatoes, Canada restricted seed imports and mandated that potatoes for consumption be treated with a sprout inhibitor and meet other requirements. Mop top causes discoloration in potatoes. It is not harmful to humans but makes potatoes inedible.