The Canadian Food Inspection Agency's (CFIA) national potato wart survey is an important element of the Government of Canada's efforts to help contain, control, and prevent the spread of potato wart. It also supports ongoing market access for all of Canada's potatoes to countries including the United States (US).
On this page
- Purpose and sampling methodology
- Selection process for field sampling
- What happens if potato wart is detected
- More information
Purpose and sampling methodology
The objective of the survey is to monitor seed potato fields for the presence of potato wart. The data from the survey is used to verify and improve the effectiveness of control measures in place. Soil samples from seed potato fields across the country are collected and analyzed. This survey builds on previous survey data collected since 2021, as well as specific and general visual surveillance that has been ongoing in PEI since 2000. The sampling rate is approximately one soil sample per acre.
In line with recommendations of the International Advisory Panel on Potato Wart Disease Management, the survey incorporates the tare soil sampling method, along with grid soil sampling.
When does the survey take place each year
Growers are notified that their fields have been selected for the survey as soon as field selection is complete. Sampling is completed annually in the fall and analysis of the samples is typically completed the following spring. Results of the survey are announced soon after.
Tare soil testing
Tare soil is the soil found on potatoes after harvest. The soil falls off during handling and storage. This sampling method collects soil falling from potato tubers while they are being handled, where each truckload represents a portion of a field. Laboratory analysis for tare soil samples follows the same strict methodology used for grid field-collected samples.
Tare soil sampling was recommended by the International Advisory Panel as an effective means to collect soil. Grid sampling is another option and is used during potato wart investigations and in the national survey, but tare soil sampling can be more efficient as a single inspector can complete the activity as the potatoes move into storage.
Learn more about how we test for potato wart in Canada.
How the 2024 survey differs from the 2023 survey
In 2024, only fields entered for seed potato certification were eligible for sampling as part of the survey. This differs slightly from the 2023 survey where non-seed potato fields in PEI were also included. As seed potatoes are the highest risk pathway for spread and establishment of potato wart, the survey in PEI once again focuses on seed potato producing fields with no known association with a potato wart detection. This change was communicated to growers in December 2023.
Newfoundland and Labrador is not included in this survey. Sampling and analysis are completed in Newfoundland and Labrador as part of the potato seed certification program.
How this survey is different from other surveillance activities
The national survey focuses on seed potato production fields that have no known association with potato wart detections. Soil samples are collected in all major potato-growing regions of Canada (except Newfoundland and Labrador where the movement of potatoes is regulated under the Plant Protection Regulations). Historical investigations into potato wart in PEI and associated ongoing surveillance activities focus on restricted fields only.
Selection process for field sampling
The criteria for field selection differs slightly between PEI and the other potato producing provinces. In PEI, the survey predominately uses tare soil collected from fields across PEI that have no known association with a potato wart detection and were entered for seed potato crop inspection for the 2024 crop year. Only one field per seed potato farm unit is selected for the Survey.
Outside of PEI, fields were selected using the same criteria that was established in 2021. Considerations include seed potato farm units that historically sell seed potatoes to the United States and fields producing varieties that are either susceptible to potato wart or not known to be resistant to potato wart.
Each year, growers are asked to submit their applications for seed potato crop inspection by June 30 as all applications must be submitted before the selection of fields for the potato survey can be completed.
How farmers are informed if their fields have been selected
Both growers and landowners (if different from the grower) are notified that their field has been selected for the survey. CFIA inspectors engage directly with individual growers who have a field(s) selected for inclusion in the survey. Growers and landowners with questions about the field selection process should contact their local CFIA office.
Why growers can't opt out
The survey is completed under the authority of federal legislation and does not allow the option to opt out when a field has been selected for the survey. Activities such as this survey are important to maintain the confidence of domestic and international trading partners in Canadian potatoes. They also help improve the effectiveness of the risk mitigation efforts being used to help prevent the further spread and establishment of the disease.
Effective management of potato wart requires a concerted effort by everyone involved. The CFIA is grateful for the cooperation of the Canadian potato sector in the implementation of the survey. This survey is an important tool for supporting continued market access and the economic prosperity of the Canadian potato industry.
Service fees
There are no services fees for soil sampling and testing as part of the national potato wart survey.
What happens if potato wart is detected
When potato wart is detected and the regulations are triggered, the CFIA takes immediate action to put restrictions on the field where the detection was made (referred to as an index field). This helps prevent the potential spread of the fungus through movement of potatoes and soil. Fields associated with the index field, identified through tracing activities, are also placed under restrictions based on the nature of their linkage to the new index field.
Compensation may be available to affected parties under the Potato Wart Compensation Regulations, 2003, for specific losses due to treatment, prohibition, restriction, or disposition related to the pest.
More information
The Plant Protection Act requires anyone who thinks they have found potato tubers with signs of potato wart to report it to the CFIA immediately.