After a detection of potato wart, the Canadian Food Inspection Agency (CFIA) immediately places phytosanitary measures on the field and initiates an investigation to identify the possible sources of the pathogen. Risk relationships are assessed between associated fields based on location (adjacent fields), as well as past and present activities that could have caused the spread of the spores (primary and secondary contact fields).
On this page
Overview
The National Potato Wart Response Plan (2025) outlines restrictions and activities that must be followed when a potato wart detection is confirmed. The response plan replaced the Potato Wart Domestic Long-Term Management Plan (2009). It sets out improved processes to help contain, control and prevent the spread of potato wart.
What has changed: New requirements
- Developing and implementing a farm-based preventive control plan that describes how they identify and control risks associated with the potential introduction and spread of potato wart
- Removing all loose soil from machinery, equipment and more, before exiting a field or farm as set out in the farm's preventive control plan
- No certification of seed potatoes on potato wart restricted fields and ongoing restrictions on index and adjacent fields
- Additional soil sampling and analysis to be completed prior to lifting of restrictions
- Additional requirements for in-province movement of potatoes and root crops produced in potato wart restricted fields
- Some fields classified as "secondary" or "D" fields under the previous plan are now primary contact fields under the response plan
- A new field of concern classification where just one potato wart spore has been detected with specified follow-up activities
- A new index – viability not confirmed classification for index fields without a link to a tuber(s) with potato wart symptoms
Print products
Summary of restrictions by field
The purpose of establishing phytosanitary measures on an index field and all associated fields is to help contain and control potato wart and prevent further spread of the pest to other fields. This information is also available in a table format in the Overview print friendly version (PDF).
Index fields
A field where a symptomatic tuber or 2 or more spores of potato wart have been detected and confirmed to be present by the CFIA.
Preventive control plan
- Develop a preventive control plan
What you can plant
- Resistant varieties of potatoes (indefinitely), or
- Above-ground crops (for example: corn, wheat, hay) for at least 20 years after a detection
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
- Freedom from soil: remove all loose soil from potatoes, equipment, machinery and more before exiting the field or farm
Where can the potatoes or root crops be moved
- Exclusively to facilities with compliance agreements
Seed potato certification
- Seed potato certification is banned indefinitely for index fields.
Release from phytosanitary measures
- Minimum of 3 resistant potato crops and 40 years before table stock potatoes can be produced
- Minimum of 5 soil sampling and analysis events after the initial investigation
Banned indefinitely
- Seed potato certification
- Planting susceptible varieties of potatoes
- Exporting potatoes grown on this field
Adjacent fields
A field directly bordering an index field and not separated from the index field by a physical barrier of more than 15 metres in width, such as a tree line, fence line, permanent waterway, ditch, or road. As well, during investigation soil sample analysis, an adjacent field has no potato wart spores detected.
Preventive control plan
- Develop a preventive control plan
What you can plant
- Potato or other root crops for processing or direct consumption, or
- Above-ground crops (for example: corn, wheat, hay)
Planting a susceptible variety is required on the last crop before soil sampling.
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
Freedom from soil is required until a "not detected" result is obtained from soil analysis after the 1st crop.
- If freedom from soil is required, remove all loose soil from potatoes, equipment, machinery and more before exiting the field or farm.
- If freedom from soil is no longer required, all machinery, equipment and conveyances must meet the equipment cleanliness definition for soil described in your preventive control plan prior to exiting the field.
Where can the potatoes or root crops be moved
- If freedom from soil is required, move potatoes and root crops exclusively to facilities with compliance agreements
- If freedom from soil is no longer required, potatoes and root crops must be dry-brushed on-farm and moved:
- only within the province of origin, or
- to a facility with a compliance agreement
Seed potato certification
- Seed potato certification is banned indefinitely.
Release from phytosanitary measures
- Minimum of 4 potato crops
- On the final crop before soil sampling, planting a susceptible variety is required
- Minimum of 2 soil sampling and analysis events after the initial investigation (after the 1st and 4th crop)
Primary contact fields
A field where common equipment or seed potatoes was moved directly after contact with an index field and where, during investigation soil sample analysis, no potato wart spores were detected.
Preventive control plan
- Develop a preventive control plan
What you can plant
- Potato or other root crops for processing or direct consumption, or
- Above-ground crops (for example: corn, wheat, hay)
Planting a susceptible variety is required on the last crop before soil sampling.
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
Freedom from soil is required until a "not detected" result is obtained from soil analysis after the 1st crop.
- If freedom from soil is required, remove all loose soil from potatoes, equipment, machinery and more before exiting the field or farm.
- If freedom from soil is no longer required, all machinery, equipment and conveyances must meet the equipment cleanliness definition for soil described in your preventive control plan prior to exiting the field.
Where can the potatoes or root crops be moved
- If freedom from soil is required, move potatoes and root crops exclusively to facilities with compliance agreements while freedom of soil is in place
- If freedom from soil is no longer required, potatoes and root crops must be dry-brushed on-farm and moved:
- only within the province of origin, or
- to a facility with a compliance agreement
Seed potato certification
- Once phytosanitary measures are released, seed potato certification is possible
Release from phytosanitary measures
- Minimum of 4 potato crops (final crop must be a susceptible variety)
- On the final crop before soil sampling, planting a susceptible variety is required
- Minimum of 2 soil sampling and analysis events after the initial investigation (after the 1st and 4th crop)
Primary contact fields that were previously secondary contact fields
Preventive control plan
- Develop a preventive control plan
What you can plant
- Potato or other root crops for processing or direct consumption, or
- Above-ground crops (for example: corn, wheat, hay)
Planting a susceptible variety is required on the last crop before soil sampling.
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
- All machinery, equipment and conveyances must meet the equipment cleanliness definition for soil described in your preventive control plan prior to exiting the field.
Where can the potatoes or root crops be moved
- Must be dry-brushed on-farm and moved:
- only within the province of origin, or
- to a facility with a compliance agreement
Seed potato certification
- Once phytosanitary measures are released, seed potato certification is possible
Release from phytosanitary measures
- Minimum of 4 potato crops
- On the final crop before soil sampling, planting a susceptible variety is required
- Minimum of 2 soil sampling and analysis events after the initial investigation (after the 1st and 4th crop)
Secondary contact fields
A field where common equipment was used after being in a primary contact field and where, during investigation soil sample analysis, no potato wart spores were detected.
Preventive control plan
- Develop a preventive control plan
What you can plant
- Potato or other root crops for processing or direct consumption
- Any variety of potato (no restrictions)
- Above-ground crops (for example: corn, wheat, hay)
Planting a susceptible variety is required on the last crop before soil sampling.
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
- All machinery, equipment and conveyances must meet the equipment cleanliness definition for soil described in your preventive control plan prior to exiting the field.
Where can the potatoes or root crops be moved
- Potatoes and root crops must be dry-brushed on-farm and moved:
- only within the province of origin, or
- to a facility with a compliance agreement
Seed potato certification
- Once phytosanitary measures are released, seed potato certification is possible
Release from phytosanitary measures
- Minimum of 2 potato crops
- On the last crop before soil sampling, planting a susceptible variety is required
- Minimum of 1 soil sampling and analysis events after the initial investigation (after the 2nd crop)
Field of concern
A field where one potato wart spore has been detected and confirmed by 2 methods of analysis (morphological and molecular).
Preventive control plan
- Develop a preventive control plan
What you can plant
- No root crops or potato production are permitted until the field is reclassified.
What written authorizations do you need
- Soil and waste disposal
- The movement of tubers and other regulated things
Equipment cleanliness
- Freedom from soil is required until a follow-up soil sampling and analysis is completed, and the field is reclassified as index or primary contact.
- Until it's been reclassified, remove all loose soil from potatoes, equipment, machinery and more before exiting the field or farm.
Where can the potatoes or root crops be moved
- Exclusively to facilities with compliance agreements
Seed potato certification
- Once the field is reclassified as index or primary, seed potato certification is possible.
Release from phytosanitary measures
- Not applicable. After a follow-up soil sampling and analysis is completed, the field will be reclassified as index or primary contact.
Definitions and terminology
- Potato wart
-
- A soil-borne fungus (Synchytrium endobioticum) that can remain dormant in a field for more than 40 years
- Poses no threat to human health, animal health or food safety
- Reduces crop yield and makes potatoes unmarketable
- Can spread through many pathways, including the movement of potatoes and soil
- Detection
-
An official CFIA confirmation of a symptomatic tuber or spores of S. endobioticum as determined by morphological identification followed by a molecular method confirmation.
- Equipment cleanliness
-
The removal of all loose adhering soil from all machinery, equipment, and conveyances before exiting the field / farm unit as per the requirements of the farm unit's preventive control plan.
- Field
-
A distinct plot of land distinguished from neighbouring plots of land by physical boundaries including a:
- tree line
- berm
- fence line
- permanent irrigation track
- permanent waterway
- transition to non-agricultural area (fallow, lawn, wetland)
- ditch
- road or permanent lane
- Freedom from soil
-
The cleanliness standard for regulated things such as equipment and machinery. Consult PI-016: Procedure for inspecting regulated articles for freedom from soil, plants, plant parts and related matter for more information.
- Laboratory bioassay
-
Growing a potato variety that is susceptible to potato wart in favourable conditions (usually in a greenhouse) in soil collected from a field to see if symptoms of potato wart develop.
- Phytosanitary measures
-
Any legislation, regulation or official procedure having the purpose to prevent the introduction and/or spread of quarantine pests, or to limit the economic impact of regulated non-quarantine pests. Consult International Standards for Phytosanitary Measures No. 5 (PDF) for more information.
- Preventive control plan
-
A written document that describes how risks to plant health are identified and controlled. It includes a combination of control measures that, when taken as a whole, provide for a science-based approach to managing risks posed by hazards, such as plant diseases, and contributes to achieving compliance with phytosanitary measures and regulatory requirements. A preventative control plan can be based on existing farm plans including on-farm biosecurity plans and may also be referred to as a 'systems approach' to mitigate pest risk(s).
- Regulated "things"
-
- S. endobioticum, in all its life stages
- potato plants (Solanum tuberosum), including tubers or parts thereof
- soil
- plants or parts thereof including root crops, nursery stock, greenhouse plants, bedding plants, vegetable transplants and sod
- machinery, implements and conveyances
- manure
- Restricted field
-
Field in which potato wart has been detected as well as land that by reason of its agricultural history, or its location, is associated with land in which potato wart has been detected. Restricted fields are classified as index, adjacent, primary contact, secondary contact or field of concern.
- Tare soil
-
Soil that falls from tubers as they move into storage or during storage and subsequent handling processes. It can accumulate beneath handling equipment at potato storages, processing facilities or other locations where the potatoes are being stored or handled.
More information
National Potato Wart Response Plan
Outlines phytosanitary measures to improve the processes used to help contain, control, and prevent the spread of potato wart in Canada (excluding Newfoundland and Labrador).
Find out if a property is affected by potato wart restrictions
Movement of potatoes and regulated things may be permitted if certain conditions are met, and will depend on the category for a field.
The requirements set out in the Potato Wart Order remain in place and are in addition to measures outlined in the response plan.
Monitors potato fields across Canada for the presence of potato wart and provides valuable data to verify the effectiveness of control measures in place.