Potato wart in PEI

Potato wart is a soil-borne fungus that can remain dormant in a field for more than 40 years.

Although potato wart poses no threat to human health or food safety, it has an impact on the economic return for potato growers by reducing yield and making potatoes unmarketable.

In Canada and many other countries, potato wart is a quarantine pest. The CFIA is therefore required to put controls in place that reduce the risks of spreading potato wart both domestically and internationally.

Potato wart is regulated under the Plant Protection Act, which means that its detection may trigger land-use restrictions, movement controls, requirements for cleaning and disinfection of equipment, soil sampling and testing. The fungus is extremely persistent and the only efficient way to control the disease is to prevent the spread into new locations.

Potato wart in PEI - recent events

On October 1, 2021, the CFIA Charlottetown Laboratory confirmed the detection of potato wart following the submission of a suspect potato by a producer.

On October 14, 2021, a subsequent detection at a second farm – also from a potato submitted by a producer – was confirmed.

On November 2, 2021, the movement of seed potatoes from PEI to the United States (US) was suspended by the CFIA, as a result of these two detections and the scope of the investigations.

After assessing the impacts from these most recent detections, it was determined that additional measures were necessary to prevent the spread of potato wart to the rest of Canada and abroad. As of November 21, 2021, a Ministerial Order was put in place to address these risks. The Order restricts the movement of seed potatoes from PEI, both internationally and domestically, and introduces new risk mitigation measures for PEI table stock and processing potatoes.

Potato wart in PEI - over time

The first potato wart detection in PEI in 2000 resulted in the closure of the US–Canada border for all fresh PEI potatoes – including seed and tablestock – for six months.

Since that detection, the CFIA has surveyed for potato wart annually in PEI. During the first three years following the initial potato wart detection, the CFIA surveyed all fields used to produce potatoes in the province. These surveys indicated that the pest was not widespread at that time.

The Potato Wart Domestic Long Term Management Plan, put in place following the detection in 2000, outlines the mandatory minimum survey, testing, and surveillance activities required, with the objective to mitigate the risk of spread of potato wart outside of the restricted areas in PEI. If potato wart is detected, land restriction controls are put in place on individual fields to restrict the movement of potatoes, plants, soil, and other articles that could result in the spread of potato wart outside of the regulated fields. The CFIA monitors approximately 1,000 fields a year for potato wart.

The CFIA laboratory in Charlottetown is responsible for confirming potato wart in samples submitted by CFIA staff. This facility is designed to prevent the spread of potato wart.

In 2003, the Potato Wart Compensation Regulations were enacted to provide compensation for specific, confirmed losses due to treatment, prohibition, restriction or disposition related to potato wart. The regulations do not compensate for potential revenue loss that has not yet occurred.

In 2015, the US put in place a Federal Order that outlines specific mitigation measures required for the movement of table stock, bulk, unwashed and seed potatoes from PEI to the US. Since then, import requirements for seed potatoes include mandatory soil testing within one year of harvest. The mitigation measures for table stock potatoes grown from a field where potato wart is not known to occur include brushing and washing to remove any soil, packing in containers of 50 lbs or less, and phytosanitary inspection and certification.

In 2021, the CFIA enhanced its National surveillance program with additional soil samples taken in every seed potato-producing region of Canada.

The science-based mitigation measures undertaken by the CFIA along with the Potato Wart Management Plan, designed to remove the risk pathways for potato wart to spread, have allowed PEI to move hundreds of millions of dollars worth of potatoes off the island.

Prince Edward Island is an important supplier of fresh potatoes to the domestic market with the bulk of the shipments going to Ontario, New Brunswick, Quebec, and Nova Scotia.