PEI potato wart mitigation efforts present a growing concern to US
The Canadian Food Inspection Agency’s recently announced risk management plans do not contain the urgency necessary to ensure that Prince Edward Island potato wart stays out of the U.S., a leading industry advocacy group said.
In December 2023, the CFIA announced plans to review and replace its current long-term risk management plan for potato wart as part of negotiations with USDA’s Animal and Plant Health Inspection Service (APHIS), which prohibits the import of field-grown seed potatoes from PEI into the U.S.
The timetable to complete that process doesn’t satisfy Kam Quarles, CEO of the National Potato Council.
“The latest chapter in this crisis happened in November of ’21, so we’re over two years since that happened,” Quarles told Spudman. “We’re over a year and a half of having product moving into the U.S. That big clock is ticking, and we want to understand: When does it actually get to the point where something changes?”
The U.S. border reopened to fresh potatoes in April 2022 after detection of PEI potato wart in 2021 completely closed the passage in November of that year. The closing led to the destruction of hundreds of millions of pounds of seed and table potatoes in the Canadian province and sparked fear of the stubborn pathogen crossing into the U.S.
CFIA completed an investigation into PEI potato wart in August 2023. An analysis of nearly 50,000 soil samples from fields associated with the 2021 detections found potato wart in four additional fields — a result “expected in investigations of this scale,” according to a statement on the CFIA website.
The agency imposes controls on fields where potato wart is detected as part of the risk mitigation plan currently being evaluated. An online public comment period seeking feedback on elements of the plan, including seed potato production in fields associated with potato wart, closed Jan. 31.
An October 2022 risk assessment by APHIS stated that PEI’s potato wart infestation is likely larger than reported and that the virus is “almost certain to be introduced” to the U.S. without additional mitigation measures.
“Right now, we’re looking at all of these public comment periods and notices and how they build on each other. What it tells us is January of ’25 at the earliest (before the plan is finalized), and that’s a lot of risk to ask the U.S. industry to hold,” Quarles said. “All it takes is one unfortunate circumstance, and the results are going to be really ugly for the U.S.”
JUSTIFIABLE CONCERNS?
Given the challenges potato wart presents, such worries are valid, said Amanda Gevens, chair of Plant Pathology at the University of Wisconsin (UW) Madison.
“There’s a lot of angst about this disease in the United States, given the proximity of these reports on Prince Edward Island,” Gevens said. “It’s very close to us in terms of geography but also very close to us in terms of the exchange of potatoes through the market space.”
Potato wart — first and last detected in the U.S. in Pennsylvania home gardens in 1918 — is not easily managed and difficult to eradicate, she said.
“The perspective on this, as a research scientist in potato pathology, is that we want to be extremely proactive and protective of our U.S. production systems, particularly our seed growers and seed production regions, because once the pathogen is introduced, it shuts down production fields,” Gevens said.
Gevens said she is not allowed to have potato wart in her lab, or to test a questionable sample.
“It has that level of alarm,” she said. “We don’t consider it something that we can tolerate at a low level. It’s something that we don’t accept at all.”
James Woodhall, an assistant professor and Extension specialist — plant pathologist at the University of Idaho, said there are two main ways to control potato wart.
“Don’t plant into infected fields and don’t move contaminated seed,” he said. “It does pop up. I think one of the issues with Prince Edward Island is they have such intensive potato production. They’ve got very tight rotations.”
PEI also has a favorable climate for the pathogen, which likes moderate rainfall, warm summers and temperatures around 64° F. The province’s warm season lasts from June 7-Sept. 19 with an average daily high above 66° F, according to weatherspark.com.
ECONOMIC STAKES
In May 2022, the U.S. shipped its first fresh potatoes into Mexico, capping a 25- year fight to fully open that market. The USDA continues to push for full market access to Japan, where restrictions on imports including table stock remain in place.
Mexico is the top destination for U.S. potato exports, with shipments growing 43% year-over-year to $111 million in 2022-23. Quarles estimates that full access to the Japanese market could be worth another $150 million to $200 million.
Such figures underscore the importance of keeping potato wart out of the U.S.
“There are certain markets that we want to sell into where the government and the industry really do want to protect their industry and keep us out,” Quarles said. “If wart legitimately showed up in a production area, it would be a matter of hours before they threw us out of their market.
“We’ve had to elbow our way in, and they would be very happy to escort us right on out if they had justification.”
The effects of potato wart would be felt within the U.S. as well, Quarles said. “You would have states prohibiting the movement, or even counties prohibiting the movement, of potatoes from one area to another,” he said. “You’ve got to consider the job loss, all the economic activity and then the cost to USDA and the individual states in terms of disaster relief and all of the various social benefits that they would need to implement.
“It’s just a staggering amount of money, certainly in the billions of dollars.”
While acknowledging a zero risk of disease transmission is not attainable, Quarles said additional risk management measures can be taken, including quarantining fields where potato wart has been detected.
“Since potatoes are the host material for potato wart, it’s pretty simple: If you don’t grow host material, you’re not going to have the ability to perpetuate wart,” he said. “Clearly, there’s got to be a heck of a lot more testing that goes on to make sure the disease isn’t moving around these adjacent fields — or they call them associated fields. You have layers of mitigation that would deal with those unimpacted fields and let business go on.”
There are layers of politics involved as well. U.S. Ambassador to Canada David Cohen visited PEI in October 2023, and Canadian Prime Minister Justin Trudeau said during a November 2023 meeting with President Joe Biden that “there’s no scientific basis for the ban of table potatoes,” according to CBC News.
“Whatever agreement was struck between the two leaders, that clearly has had an influence on what’s happening here,” Quarles said. “But just simply looking the other way and allowing product to move, when APHIS has very clearly laid out that these are real concerns — it’s just not acceptable for this industry. The amount of negative impact would be gigantic. So absolutely, we’re frustrated. We think that reasonable measures can be put in place that will both allow PEI to have a thriving business but will also protect the U.S.
“Just act. It’s not that hard.”
