Warning that American agriculture faces a potentially catastrophic economic threat, the National Potato Council is urging the immediate reinstatement of a federal ban on Canadian fresh potato imports from Prince Edward Island following a newly confirmed detection of potato wart — a highly destructive fungal disease — in a previously unregulated field.
On May 18, NPC and 13 U.S. state potato organizations, sent a letter to USDA Undersecretary for Marketing and Regulatory Services Dudley Hoskins, stressing that this new detection exposes severe vulnerabilities in current border protections and proves that the disease spreads beyond known containment zones.
“The threat is to the entirety of the industry, and we are desperately trying to avoid potato wart,” Kam Quarles, CEO of NPC told The Packer. “It is an incredibly insidious disease. It will exist in a dormant fashion in the soil for decades, and the moment it comes in contact with host material, it’s off and running again. So, the solution to potato wart is, don’t get it. That is your first and best line of defense.”
The USDA Animal and Plant Health Inspection Service currently classifies potato wart as a select agent — one of only seven high-consequence plant pathogens listed as severe threats to domestic agriculture. According to data from the Canadian Food Inspection Agency, the fungus can survive in soil for more than 40 years, and no chemical treatments exist to control or eradicate it.
NPC insists the introduction of potato wart in the U.S. would have devastating economic consequences for domestic family farms, as the U.S. potato industry generates more than $100 billion in annual economic activity and supports over 714,000 jobs. A domestic outbreak would prompt an immediate loss of access to all international fresh potato markets, costing American growers over $225 million in direct annual export losses and billions more in indirect economic damage.
“If — and this is a doomsday scenario — if potato wart got into a production area in the U.S., we are going to lose on an immediate basis, and it doesn’t matter where it is in our country, we will immediately lose our export markets overnight,” Quarles says. “The impact of that, both the direct and indirect impact, could be catastrophic for our industry. So, we are approaching this with a huge amount of sensitivity and an abundance of caution. We do not want this disease in the United States.”
Potato Wart Politicized
Quarles says while NPC “sympathizes greatly with Prince Edward Island,” there’s been a history of permissive policy around potato wart.
When a major potato wart outbreak hit the island in 2021, the U.S. government immediately halted all fresh potato imports from the Canadian province to prevent the disease from spreading. But due to the economic toll on the region, NPC says the decision triggered significant political pushback from PEI leaders, prompting the Biden administration to treat the trade dispute as a political irritant rather than a biological threat. The U.S. reopened the border to EI fresh potato imports in May 2022.
“We have, from the beginning, treated this as a phytosanitary matter,” says Quarles. “The disease does not care about political leaders. It doesn’t care about your talking points. The disease wants to get out. It wants to move, and if you’re not taking concrete steps to keep that disease under control — and the most important one is — if you are not surveying your fields comprehensively and constantly, you have a big problem, because you don’t know where this thing is.”
Despite an October 2022 APHIS pathway analysis warning that “the full extent of the potato wart infestation in PEI is still unknown but is likely to be larger than currently reported,” subsequent mitigation protocols remained largely unchanged, says NPC.
NPC previously expressed concerns over the effectiveness of Canada’s 2024 National Potato Wart Survey. The industry noted that it evaluated a very small sample size of only 2,200 fields and entirely skipped testing in fields with previous detections.
“It’s sort of surprising that a national survey picked it up, because it’s really like a 30,000-foot look at potato production across all of Canada, but it found it in an entirely new field outside of all of their regulated areas, which is where they thought the disease was confined to,” says Quarles. “But it jumped it. It’s out. It’s kind of like a fire jumping a fire break and now that’s triggered 1,000 new acres — but the field itself and then surrounding fields go under regulation to try to keep it from moving.”
Demanding Decisive Action
Potato wart can spread by infected tubers, infested soil attached to potato tubers, machinery, implements used in infested potato fields, footwear, and manure from animals that have fed on infested tubers. Symptoms above ground are rare but plants may show reduced vigor and leaf and shoot malformations. The disease is usually detected during harvest, when the infected potatoes exhibit abnormal wart-like growths.
For years, NPC and the U.S. potato industry urged APHIS to use its authority to implement common-sense risk-mitigation measures, says NPC.
The industry previously recommended:
- · Restricting bulk potato shipments into the U.S.
- · Limiting large retail shipments and mandating strict traceback labeling on consumer packages.
- · Imposing stringent controls on agricultural waste generated by processing and bulk handling facilities.
Federal authorities have not yet acted on any of these recommendations, says NPC. The group points out that if the roles were reversed, Canada would never tolerate such a permissive standard from the U.S. regarding a threat of this magnitude.
“Given the disease progression on PEI, coupled with the lack of enhanced phytosanitary actions to date, we strongly urge you to suspend PEI’s ability to ship fresh potatoes into the United States,” the letter concludes.
State signatories:
Colorado Potato Administrative Committee
Idaho Grower Shippers Association
Idaho Potato Commission
Maine Potato Board
Minnesota Area II Potato Growers
Montana Potato Improvement Association
North Carolina Potato Association
Pennsylvania Cooperative Potato Growers
Potato Growers of Michigan
Northland Potato Growers Association
Oregon Potato Commission
Washington State Potato Commission
Wisconsin Potato & Vegetable Growers Association
Quarles highlights a disparity between the rigorous protocols historically imposed on the U.S. and Canada’s current management of the potato wart outbreak on Prince Edward Island. When Idaho faced a nematode outbreak, Canada mandated an aggressive, long-term testing regimen that continues to this day — far surpassing the level of scrutiny and testing currently implemented by PEI for potato wart, he says.
“We have had to be very vocal with the Canadian government and with the public about the deficiencies in terms of their visibility on where this disease is,” says Quarles. “We have asked the Canadians to be really aggressive in terms of testing and their mitigation strategies.
“There hasn’t been really any movement on the on the USDA side,” he continues. “The only thing that’s blocked is seed potatoes coming in, so Canada has updated their mitigation strategies for how they deal with wart in terms of what their process will be going forward. And the challenge with that is they had a new plan in place, it’s been implemented and the disease is still moving around.
“From the start, we’ve been saying this is a disease issue. Deal with the disease,” he says. “There’s been a lot of politics at play here, but the time for that is just flat out over.”
