PI-005: Chapter 5 - Seed Potato Crop Inspection
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Table of Contents
- Amendment Record
- 1.0 Scope
- 2.0 References
- 3.0 Definitions, Abbreviations and Acronyms
- 3.1 Training for Crop Inspection
- 4.0 Application for Seed Potato Crop Inspection
- 5.0 Crop Inspection - Administrative Procedures
6.0 Growing Crop Certificate- Seed potato (CFIA/ACIA 1318)
- 6.1 Conditions when a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318) is not issued for a Particular Crop
- 6.2 Conditions when a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318) is not issued for any Crop on the Farm Unit
- 6.3 Revocation of a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318)
- 6.4 Combination of Multiple Crops/Lots into One Lot
- 7.0 Guidelines for Crop Assessment
- Appendix 1: Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317)
- Appendix 2: Payment Documentation for Seed Potato Crop Inspection (CFIA/ACIA 5440)
- Appendix 3: Disinfection Report (CFIA/ACIA 2415)
- Appendix 4: Inspector's Field Notes (CFIA/ACIA 1298; book order form)
- Appendix 5: Report of Field Inspection (CFIA/ACIA 1284; book order form)
- Appendix 6: Growing Crop Certificate (CFIA/ACIA 1318)
- Appendix 7: Revocation of Certification (CFIA/ACIA 2546)
- Appendix 8: Regulatory Tolerances for Field Grown Seed Potatoes
- Appendix 9: Photo Credits
The Contact for the review of this document is the National Manager of the Potato Section, Horticulture Division, Programs and Policy Branch, Canadian Food Inspection Agency (CFIA).
This directive will be updated as required. For further information or clarification, please contact the CFIA.
Content Committee representative (date)
Director, Horticulture Division (date)
Amendments to this document will be given consecutive numbers. Amendments to this document will be posted on the CFIA Intranet. With hardcopy documents, insert all amendments, remove obsolete pages and ensure the record below is completed.
|Number of amendment:||Amended by:||Date of submission for approval of amendment:||Summary of amendment and number of amended page(s):|
The Canadian seed potato certification program is based on a flush through system whereby laboratory tested disease free Nuclear Stock class material provides the basis for successive field generations of seed potatoes. After a maximum of 7 field generations, crops are no longer eligible for sale as seed. Seed potatoes under certification must meet the requirements of the Seeds Regulations Part II Seed Potatoes. Seed potato crop eligibility, in the Canadian certification program is primarily based on regulatory tolerances for visual disease readings and varietal mixtures in the crop, land use history, as well as seed source planted, laboratory testing and supporting documentation.
These procedures are intended to assist CFIA inspectors in the inspection of the growing crops of seed potatoes to determine whether they meet the standards outlined in the Seeds Regulations Part II and in Appendix 8. The main objectives of conducting crop inspections are to:
- Determine the farm unit production eligibility for crop inspection through review of the Application for Seed Potato Crop Inspection Growers' Declaration (CFIA/ACIA 1317) and confirmation of the grower's declaration.
- Assess and record the disease level, varietal purity, crop rotation, cultivation, separation and overall health of a seed potato crop.
- Determine seed status eligibility of the inspected crop and if appropriate, assign a seed class and a crop unique certification number.
Eugenia Banks (editor), 2004, Potato Field Guide, Insects, Diseases and Defects, Publication 823, Ministry of Agriculture and Food, Queens Printer for Ontario, Toronto, Ontario.
Walter R. Stevenson, Rosemary Loria, Gary D. Franc, and D. P. Weingartner (editors). 2001, Compendium of Potato Diseases. Second Edition, APS Press. American Society of Phytopathology.
Seeds Regulations Part II - Seed Potatoes, C.R.C., c.1400.
CFIA Fees Notice.
- D-97-12: Bacterial Ring Rot Testing Program for Field Grown Seed Potatoes
- D-97-08: Production, Maintenance, Multiplication and Certification of Nuclear Stock Class Seed Potatoes
- D-98-01: Import Requirements for Seed Potatoes and Other Propagative Material
- D-95-13: Submission of Fees for Field Inspection
- D-97-11: Seed Potato Certification Program – Requirements for the production of Pre-Elite seed potatoes from sources other than Nuclear Stock
- D-95-18: Seed Potato Certification Program – Investigation Procedure after Clavibacter Michiganensis Subsp. Sepedonicus Has Been Detected on a Seed Potato Farming Unit
3.0 Definitions, Abbreviations and Acronyms
Definitions for terms used in the present document can be found in the Plant Health Glossary of Terms
Note: Best Management Practices (BMP): Some of the information throughout this document will be referred to as Best Management Practices (BMP). BMPs are presented to the reader as a suggested practice to follow but not as a CFIA program requirement based on Seeds Regulations. The BMPs may not be directly linked to a program requirement but, CFIA may recommend the application of those practices where appropriate to mitigate phytosanitary risk.
BMP - Throughout the document BMPs will appear in text boxes like this one
In the case of a BMP, an inspector may provide the information to the facility if appropriate, but the facility should not consider these BMPs as a mandatory requirement.
3.1 Training for Crop Inspection
In order to qualify to perform seed potato crop inspection, the inspector must have completed the appropriate training which includes but is not limited to the following:
- Become familiar with the Seeds Regulations Part II - Seed Potatoes, C.R.C., c.1400 and directives related to the seed potato program, including the PI-005: Seed Potato Manual.
- Have participated in the national seed potato training session e.g.: Ridgetown.
- For new inspectors, participation at the Ridgetown training is mandatory (preferably within their first two years of working in the program).
- For experienced inspectors (more than three years of experience), participation every 5 years for a refresher is recommended. Also, participation as a leader is recommended as a developmental opportunity for inspectors with extensive experience.
- The two first years of crop inspection must be done in collaboration with a senior/mentor inspector. (mentoring/shadowing process).
- The first year of potato crop inspection must be done accompanied by an experienced inspector.
- During the second year of potato field inspection, the inspector should be under periodic surveillance and mentoring by an experienced inspector.
- When scheduled, participate in training session planned by the Operations Branch and the Policy and Program Branch before the crop inspection season starts.
- Prior to doing seed potato crop inspections on their own, newly trained inspectors should undergo a regional evaluation to ensure they are qualified to conduct the inspection by themselves.
4.0 Application for Seed Potato Crop Inspection
Except for the production of Nuclear Stock class seed potatoes, the form Application for Seed Potato Crop Inspection - Grower's Declaration (CFIA/ACIA 1317) (Appendix 1) must be completed and submitted to a CFIA office by the grower along with all supporting documents on, or before June 30.
An application for seed potato crop inspection may be made after June 30 only if the CFIA inspector, in consultation with the Supervisor and/or the Regional Program Officer (RPO), determines that there is still time to carry out inspection in accordance with the Seeds Regulations Part II and the grower shows that the delay in submitting the application was beyond her/his control.
For the production of Nuclear Stock class seed potatoes refer to Chapter 6 of PI-005, and D-97-08: Production, Maintenance, Multiplication and Certification of Nuclear Stock Seed Potatoes.
For every potato crop being grown on the farm unit, including all potato crops not entered for certification, the following information must be provided on the application:
- Field number (may be assigned by CFIA Inspectors);
- Fields entered for certification must be indicated by an "X";
- Variety planted;
- Number of hectares planted;
- Class planted;
- Certification number of lots planted (source of seed);
- Quantity of seed planted;
- Date of planting;
- Crop history for the previous 2 years (field history);
- Location of field (legal land description of the field location planted when available and/or a map of the area indicating where the crop was planted);
- Grower's signature and date of application.
The grower, by signing the application, declares that:
- All potato crops grown on the farm unit are listed on the application;
- All the potato crops listed are planted from Foundation or higher class seed;
- At least two of the previous year's lots from the farm unit (when applicable, see D-97-12 for further details) have been subjected to laboratory tests and not found positive for the presence of the Bacterial Ring Rot (BRR) pathogen (Clavibacter michiganensis subsp. sepedonicus). In the case that only one seed potato lot was produced and stored, it is acceptable to have results for only one lot. A farm unit application may also be considered for acceptance if the farm unit did not sell or plant any of their own seed lots i.e the lots were marketed for alternate end uses such as table or processing or if the applicant is a new seed potato grower.
- All required inspection fees defined on CFIA/ACIA 5440 (Appendix 2) in accordance with section 62 of the Seeds Regulations Part II and the CFIA fees notice have been paid in full as per D-95-13;
- Any portion of harvested potato crop sold as seed will be graded to the required tuber standards in accordance with Section 48.1 of the Seeds Regulations Part II.
The following documentation, where applicable, must be provided by the grower to support the application:
- Seed source(s) (appropriate proof of purchase or acquisition); or
- The appropriate CFIA forms or equivalent: Nuclear Stock Certificate (CFIA/ACIA 4351), Seed Tags, Record of Bulk Movement (CFIA/ACIA 2343), Certificate of Authorization (CFIA/ACIA 4378), Special Permission for Sale of Seed Potatoes Not Eligible for Official Tags (CFIA/ACIA 1278), Payment Documentation for Seed Potato Crop Inspection (CFIA/ACIA 5440);
- Results of laboratory testing from a CFIA lab or CFIA approved lab or a lab considered as equivalent i.e; USDA approved labs, where required;
- Field locations identified, preferably on a hard copy of a map (if one is not provided request one from the grower).
The inspector must review the application, clarify and address missing or erroneous information, and then either approve or decline the application before initiating and crop inspection.
In some cases, if additional documentation or information is required to support the application, the inspector may request and review them on the grower's premises prior to conducting the initial inspection. Any changes made on the application form must be noted, dated and initialled by both the grower and the inspector before the crop inspection process is initiated.
Any discrepancy questioned by an inspector over acceptance of an application, should be referred to a CFIA inspection supervisor and/or the Regional Program Officer (RPO). Once an application for crop inspection is finalized by an inspector, the application should be reviewed and approved by a CFIA supervisor and/or Regional Program Officer. A copy of the application must then be provided to the inspector assigned to that particular farm unit. The inspector or office staff will then proceed with the entry of the information contained on the application into the seed potato portion of the Multi Commodity Activity Program (MCAP) database.
A hardcopy file should be created (if not already in place) for each and every grower applying for seed potato crop inspection. All related documents should be kept in these files for further review if and when necessary. Documents should include;
- A copy of the Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317),
- Proofs of seed purchased,
- Inspector's Field Notes (CFIA/ACIA 1298),
- Copy of Reports of Field Inspection (CFIA/ACIA 1284),
- Copy ofGrowing Crop Certificate (CFIA/ACIA 1318),
- Copy ofRevocation of Certification (CFIA/ACIA 2546) if used,
- Any other relevant information such as clean up records, field map, etc.
The minimum retention period for seed potato documents is 10 years.
4.1 Certification Number
For a new grower, once the application is approved, a farm unit identification number (also referred to as a grower number) is issued by a CFIA representative. Existing seed growers maintain their identification numbers from year to year. Each field entered for certification is given a unique identification number which is used for tracking purposes throughout the certification process.
A certification number is made up of 14 digits representing specific crop year, province, district, farm unit and field. The number is assigned to a seed lot which, at the completion of the crop inspection process has been determined to meet all regulatory requirements.
For example, if a certification number was 2011-3041187-001, it would represent the following information:
- Crop year - 2011
- Province - 3 (NB)
- District - 04
- Farm unit - 1187
- Field – 001
In this case, 3041187 is the grower (farm unit) number for this farm unit.
Note: Provinces are designated as follows; 0 - Newfoundland and Labrador, 1- Prince Edward Island, 2 - Nova Scotia, 3 - New Brunswick, 4 - Quebec, 5 – Ontario, 6 – Manitoba, 7 – Saskatchewan, 8 – Alberta, 9 – British Columbia.
4.2 Existing Seed Growers
It is important to know the history of a farm unit. The status of the farm unit is established by reviewing the application, (CFIA/ACIA 1317). A grower who submitted an application and was approved for crop inspection in the previous year can be considered an existing seed grower as long as:
- All fees have been paid in accordance with the provision described in D-95-13;
- The application for inspection has been completed in accordance with section 49 of the Seeds Regulations Part II;
- the inspector was able to review the grower's declaration on the application prior to first inspection and confirm its accuracy; and
- BRR was not detected on the farm unit within the past year. If the unit was tested positive for BRR, please refer to section 4.5 for more details.
Additionally the following criteria apply:
- If the presence of the pathogen causing BRR was detected on the farm unit within the past 6 years, inspectors should refer to D-95-18: Seed Potato Certification Program - Investigation Procedures after Discoveries of Bacterial Ring Rot, Clavibacter michiganensis subsp. sepedonicus for more information and additional requirements.
4.3 New Seed Potato Growers
A new seed potato grower is:
- one that has never been a seed potato grower; or
- a grower who did not submit; or
- someone who has the CFIA approve his/her Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317) in the previous year(s).
Note: May not constitute a new grower:
- An immediate family member taking over their family's seed potato farm, or
- An individual coming from another farm unit that has had potatoes entered in the certification system in the previous two years and purchased an existing seed potato farm.
Each situation should be reviewed with the Regional Program Officer and Area Potato Specialist (APO).
BMP - The year or years prior to being part of the seed potato certification program, a new grower should implement good management practices including disease prevention. Inspectors should be able to guide the new grower to put in place such measures. This should include rigorous and complete cleaning and disinfection of all equipment and facilities. It is also recommended that they implement a procedure for visual inspection for disease and pests and sampling programs for BRR, viruses, etc.
For new seed potato growers:
- A new seed potato grower must send a request to enter the seed potato certification program to a CFIA inspector before the receipt of any seed potatoes intended for planting on their farm.
- The CFIA inspector must ensure that a new grower is aware of the Seeds Regulations Part II and relevant directives (see the reference section) regarding certification requirements and should provide copies to the prospective seed grower prior to the completion of the Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317).
- The inspector should review the application with the grower, clarify all entries and answer any questions.
- All potato handling equipment, storage facilities, tote boxes, and other equipment associated with the production of potatoes on the farm unit must be cleaned and disinfected with a registered disinfectant prior to taking possession of any seed potatoes. Cleaning and disinfection must be supervised by a CFIA inspector and documented on a Disinfection Report (CFIA/ACIA 2415) (Appendix 3) before the arrival of seed potatoes on the farm unit. Cleaning and disinfection conducted and/or verified and documented by recognized authorities, e.g. provincial government, potato growers association are acceptable to support that the cleaning and disinfection was done properly.
- All fields used by a new grower to produce seed potatoes that have been entered for certification must have been free of potatoes, including volunteers, during the previous two years. Fields that have not been entered for inspection, the inspector must be able to verify that they have been free of potatoes for at least the previous year, or they were not planted with non-certified potatoes. Proof and plan of the fields must be given to the inspector to confirm the field history.
- The application for inspection has been completed in accordance with section 49 of the Seeds Regulations Part II.
- All required inspection fees were paid as specified in D-95-13 and a CFIA/ACIA 5440 form was duly completed.
Below is a comparative table for the requirements for new and existing growers.
The following table compares requirements such as previous crop requirements, disinfection requirements, and Bacterial Ring Rot (BRR) survey requirements for existing grower and new growers.
|Requirements||Existing Growers||New Growers|
Fields to be inspected:
Same requirements as for existing growers with these additional requirements:
Fields not submitted for certification:
|BRR Survey (see directive D-97-12 section 3.2.2)||
Sample collection is done by the grower and constant supervision by CFIA inspectors is not required.
The sample regime is the same as the existing growers, but the sample collection must be done by CFIA inspectors or under their direct supervision.
A full cleaning followed by disinfection is an efficient way to prevent the spread of various pathogens. A registered disinfectant by the Pest Management Regulatory Agencies (PMRA) or Health Canada for BRR must be used for disinfection.
At all times, machinery, equipment and boxes to be transported from a commercial unit to a seed farm unit, or coming from outside the seed farm unit (contract, purchase, loan), have to be disinfected. A cleaning and disinfection log should be completed when a mandatory disinfection is done. When the inspector doubts the completion and quality of the cleaning and disinfection, or in a unique situation, the inspector could ask to be notified before each cleaning/disinfection.
- If the grower decides to have two farm units, it would be preferable for him/her to have in place a quality manual describing cleaning and disinfection procedures used between the two units. Supervision by a CFIA inspector of the disinfections between the two units is not mandatory. However, it might be necessary to verify occasionally how it is done by the grower, when time of operational staff permits it.
- It is highly recommended that all disinfection activities are recorded in a log. Please note that the log could be audited by the inspection staff.
The following table summarizes disinfection requirements such as mandatory disinfections, verification by the CFIA, and disinfection logs.
|Requirements||Mandatory disinfection?||Verification by the CFIA?||Disinfection log?|
Grower's farm units affected by BRR in the previous year
Machinery or equipment moving between:Fields to be inspected and not to be inspected from a same seed farm unit
Machinery or equipment moving between:Seed farm units from the same grower
|Highly Recommended||No||Highly Recommended|
Machinery or equipment moving between:A seed farm unit and a commercial farm unit
Loaning or renting potato storages outside the seed farm unit
Purchasing, loaning, or renting used machinery outside the seed farm unit
4.5 Seed Grower's Farm Unit(s) Affected by BRR in the Previous Year
For a seed potato farm unit identified to have grown a crop or produce potatoes affected with the pathogen causing BRR in the previous year, additional requirements apply prior to being considered eligible to produce certified seed potatoes.
- Prior to receiving new potato seed for planting, a farm unit with a confirmed presence of the pathogen causing BRR must have undergone a thorough clean up and disinfection of potato handling equipment and storages under the supervision of a CFIA inspector or recognized provincial government or potato grower association representative. (for more details, please consult D-95-18: Investigation Procedure after Clavibacter michiganensis subsp. sepedonicusem Has has Been been Detected on a Seed Potato Farming Unit).
- Fields which have produced a crop infested with the pathogen causing BRR must be inspected by a CFIA, provincial government or potato growers association inspector, and determined to have been free of potato plants (including volunteers) for two years before they can be used for potato production on a seed farm unit. The results of these inspections should be recorded and kept on file for future reference as proof of follow up. Written follow up with the grower should take place to advise him/her of your findings.
- Fields declared suspect are the areas (fields) on a farm unit, which very likely produced BRR infected potatoes and for which it was not possible to obtain a sample to conduct the investigation on the crop as specified in D-95-18: Seed Potato Certification Program - Investigation Procedures after Discoveries of Bacterial Ring Rot, Clavibacter michiganensis subsp. sepedonicus. Suspect fields are subject to the requirement for freedom from all potatoes for 2 years as above. Fields found not positive or suspect for BRR are eligible for the production of seed potatoes.
BMP - When possible, it is recommended to plant seed potatoes in fields that have been out of potato production for at least 2 years.
4.6 Breeder's Selection Seed Potatoes
In order for a grower to obtain the certification of Breeder's Selection seed potatoes, in addition to meeting the requirement for the Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317), the following conditions must be met.
- The parental material has to have been laboratory tested and not found positive for PSTVd;
- A sample of the lot or growing crop must have been laboratory tested and not found positive for the presence of the pathogen Clavibacter michiganensis subsp. sepedonicus;
- All Breeder's Selection crops must not have been planted within 10 metres of any other class of seed potatoes;
- All crops identified for certification as Breeder's Selection seed potatoes must be inspected at least twice during the growing season, and be within the tolerances specified for Foundation class seed potatoes.
Note: It is mandatory to declare Breeder's Selection crops on the same application as other potatoes on the farm unit. Breeder's Selection seed potatoes, for which a crop certificate has been issued, may be shipped between farm units within Canada only if a Certificate of Authorization is issued by a CFIA inspector and a copy accompanies the shipment. The class issued for Breeder's Selection seed, when determined to be in accordance with the tolerances specified for Foundation class seed potatoes, shall be Breeder's Selection.
4.7 Imported Seed Potatoes
Prior authorization must be obtained to import seed potatoes from the United States (continental US), whether or not they are to be entered into the Canadian Seed Potato Certification Program. Inspectors should refer to the CFIA's D-98-01: Import Requirements for Seed Potatoes and Other Propagative Material for information.
In addition to the regular information required the following information must be noted on the application (CFIA/ACIA 1317):
- Approval of required test results as per D-98-01;
- The Canadian equivalent seed class assigned to the lot as per D-98-01. Class equivalence will be assigned based on the information provided on the North American Certified Seed Potato Health Certificate (NACSPHC) supplied by the state authority upon request of the purchaser or the CFIA.
Following reception of all documents mentioned above, everything will be forwarded by the inspector to the regional program officer (RPO) for verification.
The CFIA is charging fees in accordance with the Canadian Food Inspection Agency Fees Notice and D-95-13: Seed Potato Certification Program- Submission/Refund of Fees for Field Inspection.
Anyone requiring other information regarding fees may contact any local CFIA office or visit our Fees Notice website and review the D-95-13.
The Canadian Food Inspection Agency Fees Notice is the legislation which establishes the fees the CFIA may charge in the delivery of programs.
- Part 15 of the Canadian Food Inspection Agency Fees Notice stipulates a $50.00 application fee and an inspection fee of $20.00 per hectare, with a minimum fee of $20.00. A partial hectare is not assessed an additional fee. The fees and applicable taxes must be payable to the Receiver General for Canada.
- Additional fees for phytosanitary certification and laboratory testing activities are covered separately. For more information on these fees consult the Canadian Food Inspection Agency Fees Notice.
- All application fees must be paid in full at the time the application (CFIA/ACIA 1317) is submitted to the CFIA. Inspection activities should not commence until all information and supporting documentation is submitted and verified, and all fees are paid in full by cheque, credit card, or cash.
- Once an inspector has begun an inspection of any crop, no fees or portion of that fee is refundable (see D-95-13 for more details).
- For more information on fees or refunds for fields withdrawn from certification, refer to D-95-13.
5.0 Crop Inspection - Administrative Procedures
As an inspector, it is important to build and maintain a strong working relationship with industry and be considerate of private property. Examples of good public relations for CFIA inspectors conducting crop inspections include:
- Always make a point of asking the grower or their representative to accompany you to the field for the crop inspection;
- Close all farm gates when entering and leaving fields unless otherwise agreed upon;
- Never discuss or compare one grower's crop inspection readings with another grower;
- Avoid unnecessary damage to crops while driving between fields or while conducting crop inspections;
- Take appropriate biosecurity measures, e.g. clean boots, change clothing if necessary, clean vehicle, use disinfectant as appropriate, etc.
It is the grower's responsibility to ensure that the crops entered for certification are ready for inspection. This can be done by, the grower visually checking each crop status or by hiring crop specialist to scout and rogueFootnote 1 the crops on a scheduled basis.
Proper roguing removes diseased and foreign plants and tubers from the field prior to inspections. It is not adequate to leave plants in the furrows, head lands or next to the field as these plants can still be a source of inoculum for non-infected plants.
5.1 Scheduling Inspection
Once a CFIA inspector has received an Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317) which has been reviewed and approved, the following items should be considered when planning inspection activities.
- Knowledge of the farm unit location, including the number and size of fields, will help determine how long the inspection(s) will take;
- Understanding the physical characteristics, disease reactions, growth habit, and time to crop maturity for varieties listed on the application is necessary to conduct a crop inspection appropriately
- Proper Timing of crop inspections is very important:
- First inspection should be 40-60 days after planting (plant height at least 25-35 cm);
- Subsequent inspections (not final), if necessary, should be timed at 7-14 day intervals after the first inspection;
- Final inspection should be conducted approximately 60-90 days after planting (approximately 20-30 days after the first inspection) depending on crop maturity and variety.
- It is important for the inspector to communicate with the grower to ensure the final inspection occurs before vine killing takes place, making the timing of this inspection crucial for early maturing cultivars.
After ensuring the inspector has a good understanding of the points above, the grower must be contacted to schedule an inspection. Consideration must be given to the following:
- The stage of plant growth, in order to determine the most appropriate timing for crop inspection;
- Status of roguing activities, since growers will likely want to rogue the crop prior to inspection in order to bring the crop within the regulatory standards for the applicable class; It is also relevant to mention to the grower that, because of the serious complexities of certain diseases, it is most often necessary to maintain a constant effort for the tracking, roguing and application of any phytosanitary measures throughout the growing season;
- Growers have to rogue early to not hinder the proper timing of CFIA inspections.
- Safe field re-entry times after pesticide application, for reasons of occupational health and safety;
- Preferred dates to conduct inspection activities;
- Environmental conditions, e.g. drought, environmental stress.
5.2 Final Review Prior to Field Entry
Once at the farm unit, the inspector should (if not known) introduce themselves and take the time to discuss the inspection process with the growers or representatives. The following is a list of items for the inspector to address prior to field entry:
- Update the grower or representatives on any policy changes or new regulations which may impact their operation;
- Verify that the information on theapplication (CFIA/ACIA 1317) remains accurate. Any amendments must be initialled and dated by both the inspector and the grower or representatives; the inspector must identify and gather any additional supporting documents if required;
- Identify withdrawals and/or additions, as appropriate, from the certification process and proceed with refunds or payments as per D-95-13;
- Confirm that non-certified potatoes or Certified class seed potatoes were not planted on the farm unit;
- Non-compliance with this requirement will result in the application being rejected and the farm unit will be treated as a new one and be required to meet the relevant conditions as a new seed potato grower should they wish to apply for crop inspection in future years, see section 4.3.
- Review field location and class of seed planted in each field; if a map was not supplied with the application, determine whether a map of the field can be made available to the CFIA for future reference;
- When the crop has been planted with multiple seed sources, request how the different sources were positioned in the field.
- All new lots (rented or traded fields) from outside the seed farm unit of an existing grower that have been used to produce seed potatoes must be exempt from potatoes, including volunteer plant, in the last two previous years
- This requirement does not apply if the grower can provide proof to the inspector that the rented or loaned field was used to produce potato seed in the previous two years.
- Verify the safety for field entry following any chemical applications;
- Request that any unused Seed Potato Certification Tags or Records of Bulk Movement Certificates issued for the previous year's crops be returned;
- Any issues that may affect inspections; such as disease (e.g. late blight).
An inspector should possess the following materials when conducting a crop inspection:
- A signed grower's Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317)
- Map of the fields (if supplied by the grower)
- Inspector's Field Notes(CFIA/ACIA 1298) (Appendix 4) filled with grower, variety, field number, class, seed source, hectares, and proper minimum counts of each field
- Seed Potato Crop Inspection Manual and applicable directives, variety descriptions
- Seeds Regulations Part II
- Inspector's designation card and badge
- Approved disinfectant (mixed to label rates), sprayer and brush or bucket
- Hand lens
- Handheld counter
- Plastic bags for plant samples
- Appropriate footwear, sun screen, insect repellent and protective clothing (e.g., rain gear, hat, chaps and gaiters)
5.3 Crop Inspection
When a CFIA inspector is ready to start inspection, he/she should ask the grower or grower's representative to accompany him/her to the field. The first inspection is the initial opportunity for the inspector to observe the growing crop. At this time, the plants should normally show all of the characteristics of the variety and most disease symptoms should be identifiable.
In terms of procedure and preparation, subsequent (if applicable) and final inspections are to be conducted in the same manner as the first inspection. The only notable difference is that the field entry point should never be the same as the one used in previous inspections to avoid following the identical route as the one followed during first inspection. This procedure gives the inspector more confidence in stating that the crop inspection report is an accurate reflection of the crop at that time of inspection.
General elements to observe and note on the Inspector's field notes (CFIA/ACIA 1298) (appendix 4) or on the Report of Field Inspection (CFIA/ACIA 1284) (Appendix 5) while performing a crop inspection include, but are not limited to; variety integrity, virus content, insects present, possible varietal mixture, overall crop condition (stand, vigour, and cultivation), bacterial and fungal diseases such as late blight, BRR, blackleg, wilts, abnormal plant symptoms, environmental factors, etc.
The inspector should also consider the field size to ensure it corresponds to what is declared on the grower's application. If the field size is obviously in question it should be verified for accuracy.
When entering a field it is important to verify that the variety you are about to inspect is the variety specified on the grower's application. Certification of a crop should not proceed when the variety integrity is in question.
During crop inspection, in certain situations the inspector may need to take a sample. For more information on sampling, please refer to section 5.7 of this manual.
Biosecurity processes are a set of practices used by CFIA inspectors during visits to farms or to farm establishments and facilities. They are also intended to minimize the introduction, transmission and spread of pathogens and pests in plant populations.
The CFIA believes it is important for its employees to put into practice biosecurity processes during their inspections. In so doing, the CFIA addresses industry concerns that its inspection staff may be spreading pests to plants.
When conducting inspections concerning seed potato crop inspection, CFIA staff must:
- understand and apply the appropriate level of biosecurity to prevent the transmission and spread of pathogens and potato pests;
- promote on farm biosecurity best practices; and
- encourage adherence to and implementation of biosecurity best practices within inspected farms.
Prior to complete the seed potato crop inspection, CFIA staff must be familiar with the biosecurity programs of the inspected farms and be fully prepared to enter and leave an establishment without posing a risk to biosecurity.
*Important: CFIA staff must implement a biosecurity level that is appropriate to the company being visited. However, certain establishments may have stricter biosecurity protocols. Should the biosecurity protocol of a facility differ from that of the CFIA, inspection staff must comply with the strictest standard, regardless of whether it is an industry or a CFIA protocol.
For more information related to biosecurity, please refer to the National Farm-Level Biosecurity Planning Guide - Proactive Management of Plants Resources
5.3.2 Prior to Field Entry
- Prior to arriving on the production unit, ensure that your vehicle has been cleaned and relatively free of soil. Pressure washing of the vehicle is recommended, prior to arriving at a farm unit, to remove any soil and plant debris that may be on or under the vehicle.
- If possible, park your vehicle in a location such as the side of the road or driveway, as to avoid direct entry into the field.
- Carefully clean and disinfect footwear and equipment (should be performed when arriving and leaving a farm unit).
- Begin with the highest class to be inspected that day on the farm unit and end with the lowest class. This is a good practice to reduce the probability of spreading/vectoring mechanically transmissible pest i.e; bacteria, fungus and viruses. If it is not possible to start the inspection with the higher class, boots and protective clothing disinfection must be done prior to proceed to another class inspection.
- Schedule inspections of crops, determined to be infested with late blight outbreaks at the end of the day.
5.3.3 During the Inspection
During the crop inspection, the inspector should take notes of all observations on diseases, virus, varietal mixtures, or any other aspects i.e isolation conditions or late blight. In this case, please do not forget that the inspector's duty is a visual inspection and it is important to note all observations.
The inspection should be done according to the patterns presented in section 7.1.4.
At the time of inspection, consideration should be given on the pattern choice and on the evaluation of disease level/virus content/varietal mixture, if the crop was planted with different seed sources. This information is very important as if the crop does not meet the standards, the inspector may choose to proceed with separating the field in order to allow certification for a portion of the field and reject the crop planted with a higher virus level seed source.
220.127.116.11 Suspension of Crop Inspection During the Inspection
At the first inspection, the inspector can suspend the inspection if, after a minimum number of counts (i.e 2 to 5 counts) on a portion of the field, he/she determines there is a problem that can be corrected by the grower. In a situation when a grower used more than one seed source in his/her field, the area to be inspected before any termination of the crop inspection could vary.
Following any suspension of a crop inspection, the inspector must inform the grower for which reason he/she has temporarily suspended crop inspection. The objective of the suspension is to give to the grower the opportunity to apply corrective measures (refer to section 5.4.1). The inspector needs to make sure that the grower understands the situation, and if, plants have to be rogued out because of excessive levels of diseases, viruses or mixture, and the grower is capable to do so. The inspector may choose to review the problematic areas in the field with the grower and allow them time to correct the problem prior to continuing inspections.
Once the inspector has discussed his observations with the grower, he may inform the grower that corrective measures are needed for the crop to maintain the class standards. Please refer to section 5.4 actions to be taken when crops do not meet standards.
Note: It is important to understand that if at the first field visit, the inspector decides to suspend its inspection prior to its completion; this portion of activity does not constitute the first inspection. Because the inspector stopped its activity while he was doing it and that the crop has not been totally inspected, we can't qualify it as an inspection. By definition, the first inspection is the complete first inspection of the crop.
18.104.22.168 Termination of Crop Inspection During the Inspection
During the inspection process, or upon arrival at the farm unit, conditions can be encountered which will warrant immediate termination of inspection of a specific crop, or termination of all crop inspections on the farm unit. For example, the inspection of a single crop may be terminated immediately under any of the following conditions:
- Inspection counts show excessive levels of disease or varietal mixture whereby the crop is clearly ineligible for Certified class, as noted in section 5.4.
- No blank row (2 metres minimum) separating two crops of different varieties (a grower may be given an opportunity, time line of one week from initial finding, to remove a row between the two varieties).
- There is no clear marking or separation (10 metres of blank row at both ends of the field) separating the specific crop from different classes of the same variety, and it is not possible to assign a lower class as noted in section 5.4. This may be the case if the lower class crop is rejected.
- The inspector becomes aware that the crop has been treated with a sprout inhibitor or has been exposed to a sprout inhibitor.
- As a result of late planting, lack of cultivation, excessive presence of weeds, leaf injury, pesticide or fertilizer injury, it is not possible to determine by visual inspection the variety purity or disease incidence.
- Equipment used in relation to planting, cultivating, or spraying of the crop has been exposed to contamination by regulated pathogens for e.g.: PSTVd, that are detrimental to the crop, unless the equipment, each time before entering a crop of a farm unit, has been thoroughly cleaned and disinfected in such a way as to destroy the regulated pathogens and the grower demonstrates to the inspector that the clean-up and disinfection have been completed.
- The pathogen PSTVd is known to have been detected in the crop, or the seed source used to plant the crop.
Plus, all crop inspections on a farm unit shall be terminated under any of the following conditions:
- The pathogen causing BRR or a disease of quarantine significance has been detected.
- Non-certified or Certified class seed potatoes were planted on the farm unit.
- In the case of a new grower or existing grower, the crop is growing in a field where Certified class or non-certified seed potatoes were planted in the previous two years.
- The inspector has substantive knowledge that equipment used to plant or cultivate the crop was used in a BRR infected field or a non-certified potato planted field and may be contaminated by a pathogen such as, but not limited to, BRR.
- A crop is being grown in a field where there has been the occurrence of BRR within the previous two years and the field had not been verified free of potatoes including volunteers during that period.
5.3.4 Upon Completion of Inspection
- Advise growers or their representative of the inspection results, i.e virus content, blackleg, varietal mixtures, inappropriate separation, insects, blight, etc.; and inform them of any action required prior to the next inspection in order to meet the applicable class requirements. This includes roguing, separation for varietal purity, notification prior to vine (top) killing etc.
- If the grower or their representative is not available upon completion of inspection, contact the grower as early as possible by telephone, fax or email to provide results.
- Upon completion of daily crop inspection, on a farm unit, and at the end of each day, clean and disinfect footwear and equipment prior to leaving the premise.
- When possible clothing should be changed between each farm unit. If wearing disposable gear, discard and replace with new gear, (i.e. Tyvek pants). Footwear and other non-disposable equipment and protective clothing, required to conduct crop inspection, should be cleaned and disinfected.
- Washing and cleaning the vehicle between farm units is recommended if dirty (soiled tires, wheel wells, etc.).
- Arrangements for the next inspection should be made before leaving the farm unit.
Growers planning on testing for BRR using stem samples should discuss this with the CFIA inspector at this time. It is the responsibility of the CFIA inspector to determine the earliest date a crop would be eligible for stem sampling. For further information on stem sampling for BRR inspection staff should refer to the Directive D-97-12.
While on the Farm Unit, record all crop inspection results directly on the Inspector's Field Notes (CFIA/ACIA 1298) and upon completion of inspection, determine if the observations recorded are consistent with the class intended. Changes to information on the report must be initialled and dated, and the format for recording information (blanks, dashes, lines, checkmarks, etc.) must be consistent throughout. Comments or any actions or samples taken should be recorded and dated. Any plant samples sent for lab testing must be recorded in the remarks section of the Inspector's Field Notes (CFIA/ACIA 1298). The grower is to be advised that samples are being sent to the laboratory.
5.3.5 Subsequent Inspection
A subsequent inspection is not a first or a final inspection. A subsequent inspection is used or may be necessary to review a prior assessment of a crop, if the inspector feels that he was not in a position to accurately determine disease expression or varietal mixtures at the time of their first inspection. Subsequent inspections are not to be used to allow the grower time to rogue to attain the desired class if the crop does not meet inspection standards on first crop inspection.
5.3.6 Notes on Final Inspection
One of the main focal points of the final crop inspection is the detection of varietal mixtures, possible evidence of current season virus infections, wilts and BRR. The BRR pathogen can show symptoms after approximately 70 - 90 days after planting. Final crop inspection is generally done at or close to full flowering time so it is especially important to pay attention to the floral characteristics and foliage heights of the variety being inspected. This is an opportunity to identify foreign varieties which may have delayed or different maturity, and to ensure the crop meets the disease tolerances for the required class.
As the growing season progresses, exposure to pathogens increases and the inspector should be aware of environmental conditions, such as temperature and moisture, which may influence disease levels. In addition, disease inoculum levels increase over time and potential for viral spread from virus transmitting aphids is enhanced. Virus concentration levels within plants will increase over the growing season and plants which were symptomless could now show symptoms as virus replication occurs. Inspectors should remain aware of current season virus infection which may appear as circular pockets of symptomatic plants when infested aphids move into a field and spread virus in a circular manner from the point of introduction. In addition, late blight, blackleg and early blight can develop rapidly at this time as heavy dews at night create an environment favourable for their development and spread.
5.4 Crops Not Meeting Standards
A crop may fail first or subsequent inspections and is subject to rejection or downgrading to applicable class for a variety of reasons. When a crop is downgraded or rejected, the inspector must indicate their readings and observations on the Inspector's Field Notes (CFIA/ACIA 1298) and identifies the reason(s) for rejection.
When a crop does not meet the standards applied for, the inspector must inform the grower of the inspection results. Any action required prior to the next inspection in order to meet applicable class requirements is the responsibility of the grower. A corrective action should happen prior to the next inspection and includes rouging, separation for varietal purity, etc. Recommendation of any corrective measures is at the CFIA discretion and allows the grower to take actions for this crop to maintain or meet the standards. However, it is important to note that following a crop evaluation, the CFIA may decide, at the time of inspection, to reject or downgrade the crop, without previous recommendation of corrective action.
5.4.1 Recommending Corrective Actions
Based on regulation requirements and field observations, the inspector must determine the status of the crop inspected. To assist the inspector to make such a decision, the following is a non-exhaustive list of criteria that could be used in order to assist in determining if corrective action (roguing or other) should be administered or not to determine the crop status.
Criteria that could justify the recommendation of the issuance of a corrective action:
- Observations during the first crop inspection are higher than the results expected for the applied class standard but within the following tolerances:
- Class: Certified
- Varietal Mixture: 1%
- Virus: 3%
- Black leg + virus: 3%
- Crop inspection results after the first inspection are equivalent or slightly higher than the minimal class standard applied for. As the virus content is likely to be higher at the second inspection, it is better to recommend a corrective action (i.e roguing).
- When the total areas for roguing or any other corrective actions are necessary and within reason, it is realistic that the corrective actions will be taken, i.e determine the area to be rogued.
- Following observations, the inspector is confident that with subsequent inspections, they will still be able to determine the criteria for the crop status.
- The inspector shows the grower affected plants with virus or any other problems and he is able to recognize the symptoms easily. At this time, the inspector is confident that the grower will be able to remove enough problematic plants by roguing.
- The variety, crop condition and maturity (plant size, senescence, etc.) are at optimal conditions.
- The farm history has showed its capacity and efficacy to rogue fields with success.
- Corrective actions are put in place immediately or within a given period of time by the inspector.
- Any other possible reason.
A recommendation for a corrective measure should not be issued for the same problem twice. Failing to correct the situation, the crop concerned will be downgraded or rejected from the Canadian Certification Program.
BMP - Based on the information received from the inspector, the grower could submit to the CFIA an action plan, verbal or written, presenting the corrective measures which will be deployed in the fields concerned in order to correct the situation.
When possible, the producer should initiate the implementation of the corrective actions while the inspector is on the farm unit in order to be able to refer to him, if needed. Once the corrective actions requested are completed, the producer must contact the inspector to conduct the first complete inspection, a subsequent inspection or the final inspection.
5.4.2 Crop Down Classed or Decertified
A crop not meeting the standards for the class applied for will be downgraded to the class for which the standards are met. Crops that are downgraded will continue to be inspected, but will be required to meet the standards for an appropriate class. Reasons for downgrading a crop may include:
- Inspection counts show disease or varietal mixture in excess of standards.
- In case of no clear marking or separation, an indentation of a minimum of 10 metres of blank row at both ends of the field for crops of the same variety and different classes, or a separation (i.e; blank row), between the two crops of the same variety, the two crops will be downgraded to the lower of the 2 classes. If they are different varieties refer to section 5.4.1 of this manual.
If the crop does not meet the standards for Certified class seed potatoes on the first or during subsequent or final inspection, the crop must be rejected as seed. The inspector must indicate the reason for the rejection on the Report of Field Inspection (CFIA/ACIA 1284) (Appendix 5). Rejected crops require no further inspection in regards to seed potato certification. However, they must be recorded in MCAP.
5.5 Conditions Warranting Rescheduling of Crop Inspection
A crop inspection may be rescheduled if:
- The plant growth or environmental conditions are not favourable for a good inspection (e.g. strong winds, excessive presence of weeds, wilted plants due to drought, recently cultivated, insufficient plant growth, etc.).
- Excessive foliar damage is present (e.g. damage from frost, hail, insect damage, fungus, etc.).
- The environmental conditions are not safe. Most pesticides have safe field re-entry times listed on the label (e.g. 24- 72 hours). Encourage growers to post signs at the edge of the field which indicate any chemicals applied and date of safe re-entry. Consulting the appropriate guides is recommended to determine a specific chemical safe re-entry time.
5.6 Official Reporting of all Crop Inspection Results
Once the inspector has returned to the office (after final crop inspection), the Report of Field Inspection (CFIA/ACIA 1284) is produced from the Inspector's Field Notes (CFIA/ACIA 1298) and is entered into the MCAP system and becomes the finished copy of the crop inspection. All information contained within the Inspector's Field Notes is transcribed except any personal notes not pertinent to the final classification and designation of that crop (e.g., lot history, etc.). All corrections to the pre-printed information on the report must be initialled and dated by the inspector. All areas on thereport requiring an inspector's name and date must be filled in.
Upon completion of all crop inspections on a farm unit for the season, the original copy of the Report of Field Inspection (CFIA/ACIA 1284 ) are to be filed in the local CFIA office. A copy of each Report of Field Inspection must be provided to the grower along with the Growing Crop Certificate (CFIA/ACIA 1318) (Section 6 and Appendix 6) as soon as they are ready.
Note: All field reports and growing crop certificates should be checked for accuracy and proper completion, ideally by another inspector, prior to sending them to the grower.
5.7 Sample Collection and Submission
Sampling is a routine function of an inspector's duties.
Sample collection and laboratory diagnosis may be required under various circumstances. It is essential that inspectors understand that an inspection, to assess various factors in a crop i.e; common virus present, blackleg, etc. to the regulatory tolerances established in the Seeds Regulations Part II, is based on a visual observations. A laboratory test can help to distinguish a disease versus a physiological condition, or to confirm field observations. The inspector, who wants to get confirmation of his /her diagnosis, in particular cases, may consult his supervisor or RPO for help or complementary information. If decided that a sample is taken, inform the RPO and/or APS.
There are other circumstances which could warrant sampling for laboratory analysis including, but not limited to, importing countries phytosanitary certification requirements for Canadian seed potatoes, suspecting the presence of a new pest or disease, investigative testing, surveys, or where there is suspicion of a zero tolerance regulated pest such as PSTVd, BRR, or a quarantine pest, for example potato cyst nematode.
The supervisor, the RPO and/or APS should be informed immediately when a sample is taken. The grower should also be advised of all samples taken from the farm unit for further analysis.
Samples should be taken according to relevant protocols and detailed instructions from Program Branch and/or the appropriate labs. Depending on various testing purposes, different parts of an individual plant such as leaves, stems, roots or tubers showing symptoms (or not, as appropriate) may need to be collected. Samples taken should be noted in the remarks section of the Inspector's Field Notes (CFIA/ACIA 1298) and include the date of sampling and the reason for taking the sample. The Plant Health Potato web form in the Laboratory Sample Tracking System (LSTS) must be completed for each submission and submitted online and by e-mail to the appropriate laboratory prior to shipping the samples. The submission form must contain the following information:
- Grower's name, farm unit;
- Crop year;
- Grower number;
- Identifier number (may use certificate number of the field);
- Sample type and size;
- Plant genus: Solanum and species: tuberosum;
- Reason for submission (specific suspect diseases or virus strains);
- Date collected;
- Local sample ID;
- Individual collecting the sample;
- Inspector submitting the sample.
Samples must be labelled, packaged and shipped to the appropriate labs depending what analysis should be conducted on the sample. Consult with the lab and the RPO or APO to confirm appropriate shipping methods and the destination.
Note: It is recommended to not ship any samples if they will arrive at the lab on weekends and official holidays unless prior arrangements have been made. CFIA staff is usually not available to receive samples on weekends and holidays and it may result in deteriorated samples being no longer acceptable for analysis.
Results will be released to the inspector who has submitted the sample and any other identified supervisor or program officer. In some cases, such as a Clavibacter michiganensis subsp. sepedonicus positive or a detection of a quarantine pest, only to the Area Potato Specialist and the National Manager of the Potato Section will be initially notified. Additionally, results can be distributed as needed upon request if there are special requirements. Laboratory analysts will not give out verbal results. All results must be approved and released in accordance with standard operating procedures in place in the appropriate CFIA labs. Results will be only distributed internally within the CFIA.
6.0 Growing Crop Certificate- Seed potato (CFIA/ACIA 1318)
Where an inspector has inspected crops in a farm unit and determined that they meet all the standards as set out in the Seeds Regulations Part II for the applicable class of seed potatoes, the Growing Crop Certificate (CFIA/ACIA 1318) shall be issued by a CFIA inspector or the Regional Program Officer. In addition to the grower and farm unit information, for each crop the certificate must specify:
- The class and variety of each crop of seed potatoes
- For Breeder's Selection seed potatoes, the variety, clone identification, provided on the application (CFIA/ACIA 1317)
- The number of hectares that passed inspection
- The certification number
When changes are made to the Growing Crop Certificate, such as the combining of lots after harvest, the original certificate should be revoked by issuing a Revocation of Certification (CFIA/ACIA 2546) (Appendix 7) and a new Growing Crop Certificate may be issued provided that all stated crops/lots continue to meet regulatory requirements.
6.1 Conditions when a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318) is not issued for a Particular Crop
The Growing Crop Certificate shall not be issued with respect to an individual crop, if the inspector becomes aware of certain circumstances after the final inspection. Some of these following circumstances may have become apparent after or during final inspection, in which it may terminate the inspection (Section 22.214.171.124):
- The crop was not top-killed as directed by an inspector when necessary, or
- The crop was top-killed or not suitable to conduct a minimum of two crop inspections, or
- The crop has been treated with a sprout inhibitor or has been exposed to a sprout inhibitor, as in the case of drifting from another field, or
- If the inspector determines that the crop has been infected with PSTVd or seedinfected with that pathogen was used to plant the crop.
6.2 Conditions when a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318) is not issued for any Crop on the Farm Unit
The Growing Crop Certificate shall not be issued with respect to any of the crops produced on a Farm Unit, under any of the following circumstances:
- Any common or custom equipment was used in cutting tubers infested with BRR, or in planting, spraying or cultivating a crop infested with BRR unless the equipment, each time prior to entering a field of the farm unit, has been thoroughly cleaned and disinfected in such a way as to destroy the contamination, prevent the infection of the crop and the grower demonstrates to the inspector's satisfaction that the clean-up and disinfection have been completed;
- It is evident through crop inspection or testing in a laboratory that the crop has been contaminated with Clavibacter michiganensis subsp. sepedonicus or a pest of quarantine significance.
6.3 Revocation of a Growing Crop Certificate - Seed Potato (CFIA/ACIA 1318)
There are circumstances when a Growing Crop Certificate has been issued, but information may become available after the issuance, deeming it necessary to revoke the certificate.
With respect to an individual crop the Growing Crop Certificate may be revoked at any time if the inspector determines that the crop was subject to any of the following circumstances:
- Has been exposed to sprout inhibitors or other harmful chemicals;
- Has lost its identity;
- Has lost its ability to propagate;
- Is infected with PSTVd or was produced from seed potatoes infected with PSTVd.
With respect to all of the crops produced on a Farm Unit a Growing Crop Certificate(s) may be revoked at any time under any of the following circumstances:
- The inspector determines that any one of the lots is infected with Clavibacter michiganensis subsp. sepedonicus.
- Any one of the lots has come in contact with a Clavibacter michiganensis subsp. sepedonicus or any common or custom equipment used on a potato operation which was infested with Clavibacter michiganensis subsp. sepedonicus, unless an inspector has verified that a clean-up and disinfection of the equipment had been completed before use of the equipment on the farm unit.
- The inspector determines that non-certified potatoes from another farm unit are stored with the certified seed potatoes.
- The certified seed potatoes are stored, graded or handled with common equipment that has not been satisfactorily cleaned and disinfected after being used to handle non-certified potatoes.
If a Growing Crop Certificate (CFIA/ACIA 1318) is to be revoked, the Revocation of Certification form (CFIA/ACIA 2546) should be used and a copy kept on file.
6.4 Combination of Multiple Crops/Lots into One Lot
In response to a grower's request, an inspector may combine multiple crops of the same variety that have been determined to meet the applicable class, into one lot.
- If multiple lots of different classes of a single variety are stored in the same bin without proper separation, to prevent the mixing of classes, the CFIA inspector must than adjust and retain only the certificate number of the lot with the lowest class.
- If multiple lots of the same class of a single variety are stored in the same bin without separation, then the seed potatoes will be given the certificate number of the lot with the highest disease percentage.
In both circumstances, the chosen certificate number will be put on the Report of Field Inspection (CFIA/ACIA 1284) for all the relevant crops, while their field numbers and inspection recordings remain same. The combined lot will represent all the relevant crops on the Growing Crop Certificate (CFIA/ACIA 1318).
In the event that the crops/lots were combined after the certificate was issued, the original Growing Crop Certificate must be revoked, corrected and reissued. The inspector should refer to the MCAP manual for detailed instructions on combining multiple fields, crops and lots in MCAP.
Note: Some export markets do not allow for the combination of fields (i.e Mexico, Uruguay etc.), therefore inspectors should checked with their respective Regional Program Officer for specific market information before getting agreement from the grower to proceed with combining fields, crops or lots.
7.0 Guidelines for Crop Assessment
Once a seed potato crop has been determined to be eligible for crop inspection, it will be inspected to confirm variety identity and determine compliance with the regulatory standards for the various classes of seed potatoes under the Seeds Regulations Part II, as well as to assess the overall health status of the crop. Appendix 8 lists tolerances for defects, diseases and varietal mixtures upon first, subsequent, and final crop inspection for all classes of seed potatoes, with the exception of Nuclear Stock class. Diseases scored under the tolerances for field grown seed potatoes, seed potato crop entered for certification, may consist of bacteria, fungi, viruses, or other biological entities affecting seed potato quality. The damage that they cause varies from year to year depending on a number of biotic and abiotic factors.
During crop inspection the inspector attempts to confirm variety identity and accurately describe the status of a crop at the time of inspection based on random visual examinations of growing plants performed by walking through the fields. Any abnormal and/or unusual cultural conditions observed in the field are also recorded. To perform crop inspection an inspector must be familiar with symptom recognition as well as some of the terminology used to describe disease symptoms or physiological disorders.
This section is intended to be used as general guide in assisting inspection staff in assessing potato plants and in completing the Inspector's Field Notes (CFIA/ACIA 1298). Inspectors should refer to the variety descriptions and other relevant documentation to confirm variety integrity.
The following seven images are some of the most common terms used in describing symptoms on potato plants:
Chlorosis - Abnormal light green or yellow coloration of leaves due to insufficient production of chlorophyll, which may be caused by lack of light, mineral deficiency, infection (particular with viruses), or genetic factors.
a and b: Lesion - A distinct area of diseased plant tissue. A canker on the stem (a) or a confined area of necrosis on the leaf (b).
Mottling - A variegated pattern marked with yellowish spots or patches of many colours or shades.
Necrosis - Death of plant cells or plant tissues, usually accompanied by darkening or discoloration, occurring as a disease symptom.
Rotting - Disintegration and decomposition of plant tissue, and may be of two general types, dry rot or soft rot. A dry rot is a firm dry decay; and a soft rot is soft, usually watery, and often odoriferous.
Rugose Mosaic - Severe mosaic accompanied by deformation such as crinkling, curling or ruffling of the leaf surface, usually caused by a combination of multiple viruses.
Variegation - Uneven green colour patches, spots, or streaks on plant leaves with sharply defined borders of colour changes. This feature differs from the viral infection complex called mosaic. Mosaic is not as pronounced, and the light and dark areas have more diffuse boundaries (mottling).
7.1 Assessing and Scoring Diseases Requiring Counts
Plant counts are used to determine disease infection and varietal mixtures levels in the field. They are taken at regular intervals in a randomized pattern throughout the crop/field to ensure the inspection results are representative of disease levels and varietal mixtures in the field. One count consists of 100 consecutive plants in a row. They can be counted individually or by a calculated field pace as indicated below.
The actual number of diseased plants or varietal mixtures per count is recorded and used to determine the percentage within the following categories in the Inspector's Field Notes (CFIA/ACIA 1298). Additionally, any plant parts including tubers not properly rogued should be included in the above inspection count.
- Number of plants showing mosaic
- Number of plants showing Potato Leafroll Virus (PLRV)
- Number of plants showing blackleg
- Number of plants showing wilts
- Number of foreign plants (plant of different variety)
- % misses
Here are some basic calculations that inspection staff should be aware of:
- There are 43,560 sq ft per acre.
- There are 2.471 acres/hectare (ac/ha) or .405 hectares/ac.
- E.g. at 12 in. (30 cm) plant spacing within row and a 36 in. (90 cm) row spacing, there is 1 plant per 3 sq ft (0.27 m2.).
With a fixed row distance of 36 in., Plant density can be estimated for any particular field based on the various plant spacing within row assumptions below:
- 8 in (20cm) spacing = 21,780 plants/ac or 53,800 plants/ha
- 10 in (25cm) spacing = 17,424 plants/ac or 43,037 plants/ha
- 12 in (30cm) spacing = 14,520 plants/ac or 35,880 plants/ha
- 16 in (40cm) spacing = 10,890 plants/ac or 26,900 plants/ha
7.1.1. Determining the field pace
It is important to precisely establish how many paces constitute a single count of 100 plants. A field pace can be established as follows:
- Mark a row in the field (at least 10 m away from the edge of the field);
- Manually count out 100 plants, and then mark the end of the count;
- The number of paces on average to go from start to finish will constitute the pace/count ratio.
- Inspectors should pace the 100 plant count using the same pace as when they conduct field inspections. Small variations in this crucial step can make a significant difference on pest incidence calculations once the inspection is completed.
Generally, the number of paces per count of 100 plants will range from 30 - 40 paces, depending on the size of pace, plant spacing, and number of plant misses in the field. As planting densities can vary according to planting date, variety, soil type etc., the process of field pace determination should be repeated every time a new field is inspected.
Note: Consider, as the day goes by, your individual paces may be reduced in length, owing to fatigue. You may need to re-evaluate your number of paces to adjust your plant count.
7.1.2. Establishing the Minimum Number of Counts
It is essential to establish and inspect each crop using a minimum number of counts depending on the class planted and field size as outlined in Table 7-1.
Note: Infected plants which are observed but not part of a count should be noted in the comment section of the Inspector's Field Notes (CFIA/ACIA 1298).
The following table is a guide intended to assist in determining the number of inspection counts based on the class planted, and the field size in hectares.
|Class Planted||Field Size (Ha)||Min. # of Counts|
|Pre-Elite||N.A.||Min of 10% of plants or 10 counts if feasible|
|E-1 to Foundation||< 1.0||Min of 10% of plants or 10 counts if feasible|
|E-1 to Foundation||1.0 - 1.5||10|
|E-1 to Foundation||> 1.5 - 5.0||15|
|E-1 to Foundation||> 5.0 - 10.0||20|
|E-1 to Foundation||>10.0 - 15.0||25|
|E-1 to Foundation||>15.0 - 20.0||30|
|E-1 to Foundation||>20.0 - 25.0||35|
|E-1 to Foundation||>25.0 - 30.0||40|
|E-1 to Foundation||>30.0 - 35.0||45|
|E-1 to Foundation||>35.0||50|
In the case of a Pre-Elite class planted crop, inspect at least 10% of plants or 10 counts. This can be determined as follows:
- Estimated plant density (based on plant spacing) × # of hectares = total plants
- Total plants × 10% = Number of plants to examine
- Number of plants to examine / 100 = Number of counts
- Inspect a minimum of 10 counts if feasible
Additionally, there are times when inspectors may encounter situations where standard calculations will not give an accurate representation of disease count percentages. For example, an inspector may take 10 counts and find no diseased plants in those counts but the inspector may have seen a number of diseased plants in the field, outside the counted area. The count thus shows zero percentage but it is quite apparent that the field is not totally free from disease or varietal mixture. In such a situation, the inspector should take a few additional counts to enhance their field coverage and inspection results precision. If counts are still clear, the inspector should note the disease or foreign plants in the remarks section of their field report, and bring it to the grower's attention since these finds, if not removed, it could especially affect the class to be assigned in high generation planted crops.
In calculating misses, inspectors must also take random counts, concentrating on the number of plants missing within the count. These random counts are then used to calculate the average percentage of missing plants.
Example – Calculation of misses, foreign plants and disease percentages:
Consider a crop inspection of a field where 50 counts (100 plants per count) are taken; Out of the 50 counts, 7 plants with leafroll and 13 plants with mosaic are found in total.
Disease infection level for leafroll and mosaic would be calculated as follows;
Number of leafroll plants divided by the total number of plant counted, multiplied by 100% (7/5000) × 100% = 0.14%. Same for procedure for calculating percentage of Mosaic: (13/5000) × 100% = 0.26%
The total virus incidence = 20/5000 × 100% = 0.4%. If this total virus incidence was obtained on final inspection, the eligible class to be assigned would be Foundation if Elite 4 or a higher class were planted.
7.1.3. Field Plots Planted in Tuber Units
a) Where tuber units are identifiable, count 100 units. This is considered as one count, e.g., if tubers were cut in 4 pieces and planted consecutively, count 400 plants and diseased plants are counted by unit (one unit = 4 infected plants in sequence). Growers may choose to use tuber uniting as good crop management practice although it is no longer a regulated procedure.
Note: Tuber unit sizes may vary, as a tuber can be cut in several pieces, (2, 4, 6, etc.). As long as the tuber seed pieces are planted consecutively and can be identified as one unit, they would be considered as units. Also, the planting of whole seed can be considered as tuber united.
b) Where the grower has indicated tuber unit planting on the application and the inspector is unable to accurately identify the units, consultation with the grower must take place to verify the method of tuber uniting. If difficulty persists and units are still not identifiable, treat the field as scatter/mass planted where a count is 100 plants and each infected plant is counted as one plant.
7.1.4 Patterns for Walking the Field to Ensure Random Sampling
The inspector shall walk the field and make a random examination of the plants including/covering both sides of the field either following a figure "X" pattern or an inverted "V" pattern, except when inspecting 100% of the plants. These two patterns generally give the inspector the highest degree of randomness and allow the greatest surface area of the field and the highest number of plants to be covered while reducing the chances of omitting a pocket of infestation. If the field configuration does not allow for this type of pattern it is up to the discretion of the inspector to use the most random method possible to ensure the field is properly covered.
For fields using centre pivot irrigation, a "V" or triangular pattern to the center of the pivot should be followed for each inspection. This should be followed by two additional and shorter modified "V" patterns to complete the inspection. Sample patterns for inspecting circles and irregular shaped fields are given below (Figure 7-1). The pattern in the field and entry point (as noted in section 4.3) should be predetermined and varied between inspections. These two patterns, as illustrated below, will give the highest degree of randomness and allow the greatest surface area of the field and highest number of plants to be covered while reducing the chances of omitting a pocket of infestation.
The following images are sample patterns for inspecting circular and irregularly shaped fields.
The following image is an example of a zigzag method for taking counts through the field.
7.1.5 Assessing Symptoms of Mosaic
Leaf symptoms which are referred to as mosaic are a result of potato plants being infected with certain potato viruses. The symptoms may range in severity from slight mottling to severe crinkling of leaves and stunting of plants. Some of the potato viruses are often referred to as latent viruses because they can be carried in plants or tubers without causing any visible symptoms. Depending on the variety and/or the weather conditions it may also affect symptom expression. Cool, cloudy weather may make the symptoms more pronounced. The presence of more than one virus in the plant may affect the types of symptoms and increase the severity. As well, it is important to note symptoms of the same virus are often expressed very differently depending on the variety.
In general, leaves of virus affected plants are mottled often with some areas of light green to yellow and some darker green than normal. Mottled areas may vary in size and occur both on and between the leaf veins. Leaf margins may be wavy, and the leaves may appear slightly rugose where the veins and interveinal areas are raised. Symptoms caused by different viruses shown below can vary; but they are all scored under the tolerance for mosaic.
The following six images are examples of symptoms of Mosaic on the plants Chieftain, Atlantic, Goldrush, Superior, Red Pontiac and Shepody.
A) Potato Virus Y (PVY)
PVY has a worldwide distribution and is one of the most important viruses affecting potato production. There is little to no evidence of PVY being effectively mechanically spread between plants by foliar contact, and by tuber-to-tuber transmission under general production practices. However, transmission in a non-persistent manner by aphid vectors is considered to be the most important method of natural spread in the field.
There are several strains of PVY which have been identified in North American potato production. While all are scored as Mosaic,the inspector should be familiar with the following three strains.
- PVYo: Ordinary Strain
Symptoms can range from very mild mosaic to severe foliar necrosis, sometimes leading to plant death. Symptoms can be on a single branch (leaf) only, which can make field identification difficult. In secondary infections, symptoms can include dwarfing, severe mottle which is variable in size and not necessarily bordered by leaf veins. Leaflets are usually malformed. In some cases, necrotic streaks can develop around veins (vein banding) and stems (stipple-streak). At low and high temperatures, symptoms can be masked. PVYo has been known to cause severe yield loss. Infected leaves frequently develop necrotic spots. Plants are stunted, lower petioles and leaves turn yellow, and dead leaves cling to the stem. Leaves crinkle and curl.
This is often referred to as the tobacco veinal necrosis strain, which causes very mild or mottling or no visible symptoms in potato plants.
Symptoms of this strain include interveinal chlorosis and leaf crinkle. Secondary infection symptoms: distinct mosaic, severe necrosis on stems, leaves and leaf drop; they become more visible under higher temperatures. Secondary infections will exhibit a distinct mosaic, severe necrosis on stems, leaves, and eventually leaf drop. Necrotic ring spots may occur in the tubers of certain varieties, including Yukon Gold.
B) Potato Virus A (PVA)
PVA is transmitted by at least seven different aphid species including the green peach aphid and the potato aphid. It is a non-persistent type virus. Leaves may show mild, crinkle and veinal mosaic, stems tend to bend slightly outward. Rugose symptoms can also be caused if combined with certain strains of PVA and PVY. Similar to other viruses, PVA is transmitted from one generation to the next by planting infected tubers.
C) Potato Virus S (PVS)
PVS is typically symptomless, though some varieties show slight deepening of leaf veins, rugosity of leaves, possible stunting, mottling or bronzing. Combined with PVX, PVS leads to more yield reduction than if either virus is present alone. It is believed that mature plants are resistant to PVS. It can be transmitted by seed, aphids (non-persistent), seed cutting, and injury during field operations, leaf-to-leaf contact and sprout contact before planting.
D) Potato Virus X (PVX)
PVX is the most widespread of the potato viruses. Sometimes it is referred to as potato mottle virus and latent mosaic because it is often symptomless. Some strains do not produce visible symptoms, while others will slightly reduce total yield and/or cause a mild crinkle particularly in mixed infections. PVX is carried in tubers, transmitted mechanically and by plant-to-plant contact in the field and sprout contact before planting. There are no known aphid vectors.
E) Tobacco Rattle Virus (TRV)
Tobacco Rattle Virus (TRV) is also known as corky ring spot, stem mottle and spraing. This virus is soil-borne, transmitted by stubby nematodes of the genus Trichodorus, and occurs mainly in lighter soils. Its host range includes plant species from over 50 families. Only certain potato varieties develop spraing symptoms; while others remain symptomless. Appearance and severity of symptoms vary considerably with varieties, but they are manifested in the form of alternating green/pale green to bright yellow patches. Patches are coarser, more yellow, and more irregular than mosaic.
F) Alfalfa Mosaic Virus (AMV, Calico)
Alfalfa Mosaic Virus (AMV, Calico) is transmitted by at least 16 species of aphids with pea aphid as the most common vector. Infection often occurs on edges of fields located near alfalfa. Little or no secondary spread occurs within the potato field. AMV can also be transmitted to the next generation through the progeny. Symptoms appear as pale to bright yellow mottling or blotching of leaves. Some strains cause severe stunting and necrosis of stems and tubers. AMV produces distinct calico mosaic symptoms on potato and other solanaceous crops.
7.1.6 Assessing Symptoms of Potato Leafroll Virus (PLRV)
Symptoms scored as Leafroll are caused by the Potato Leafroll Virus (PLRV). Other hosts of this virus include solanaceous crops and weeds, such as, but not limited to, tomato, pepper, eggplant, tobacco, and jimsonweed.
Chronic or seed borne infection occurs when plants are grown from tubers infected with PLRV. Symptoms of chronic infections generally develop on the lower leaves, which will roll upward, become stiff, dry, and leathery, turn light in color, and make a crisp, papery sound when touched or shaken. Plants may be stunted or rigid with light leaf yellowing in the crown and older leaves may become discoloured, turn brown and die.
Current season PLRV infection occurs when plants are infected later in the season when aphids are present, most notably the green peach aphid. If infection occurs early in the growing season, symptoms may appear mainly in the young leaves, often near the top of the plant, which usually stand upright, roll and will become slightly pale. Young leaves may turn pink to reddish in color beginning at the margins on red-skinned varieties; the leaves of white-skinned or russet varieties often turn yellow. Late season infections often do not exhibit symptoms. Current season spread of PLRV can cause tuber necrosis in certain varieties.
The following four images are examples of Potato Leaf Roll Virus in the plants Kennebec, Superior, Red Pontiac, and Goldrush.
7.1.7 Assessing Symptoms of Blackleg (Pectobacterium atrosepticum)
When the plant is infected from diseased seed potatoes, the stems will show an inky black decay, extending up the stem from the seed piece. If the plant becomes infected through wounds on the plant, the rot will extend up and down the stem from the point of infection. Infected plants are often stunted and have a stiff, erect growth, and turn pale green or yellow.
Blackleg is carried in or on tubers and can be transmitted to healthy tubers during handling and planting operations. Wind-blown rain and irrigation water may also be sources of inoculum. Additionally when seed harvesting is done in wet conditions in the fall, the Blackleg pathogen may spread during storage. Cool temperatures (10-15°C) and wet soils in the spring followed by warmer temperatures (above 20°C) following plant emergence stimulate development of Blackleg. In cool springs, infected seed pieces may rot before emerging, resulting in uneven stands.
Field symptoms may be expressed at any time during the growing season. Loss of vigour and black, slimy lesions extending from the infected seed piece will occur in warm and wet springs. Plants appear stunted, stiff and erect. Leaves appear chlorotic, and leaflets may roll upwards and cup at the margins. Small water soaked lesions may appear at the base of the stem. Lesions can rapidly become extensive and progress to the upper canopy. Stem piths will usually be decayed well beyond visible lesions. Affected aerial tissue appears soft in humid conditions, and becomes shrivelled in dry environments. Around flowering, some stems may suddenly wilt. Infected tissue is often invaded by secondary bacteria, which produces a fishy odour.
Aerial stem rot can affect all visible plant parts; it does not originate from infected seed pieces. Symptoms appear as a water-soaked green decay that turns light brown or black. On older plants, interveinal yellowing and browning and the upward cupping of leaves are characteristic symptoms.
The following four images are examples of blackleg infection.
7.1.8 Assessing Symptoms of Wilts
Symptoms develop under conditions of warm temperatures, low soil moisture and low fertility. At first the lower leaves wilt, yellow and later turn brown. As time progresses, these symptoms move upwards on the plant. At first only a single stem may show symptoms. The vascular bundles in the lower part of the stem show a brown discoloration that can best be seen if the stems are cut near ground level. Named for the casual pathogen, the two most common wilts are Fusarium wilt and Verticillium wilt, which are both scored under the tolerance for wilts on the form CFIA/ACIA 1298.
A) Fusarium Wilt (Fusarium spp.)
Fusarium overwinters in the soil and on seed potatoes tubers in storage, providing the inoculum that infects developing tubers through root wounds in the spring when temperatures exceed 20°C. The fungus attacks the vascular tissue in plants, causing wilt. Initial symptoms include stunting and sporadic chlorosis. Tips or margins of lower leaves turn yellow, then tan before drying up and hanging on the plant. Over time, the disease will move up the plant. Infected plants will appear to recover during the night, but show very visible wilt symptoms under high daytime temperatures.
B) Verticillium Wilt (Verticillium dahliae)
This disease is also commonly referred to as Early Dying Syndrome. The causal pathogen is a soil borne fungus called Verticillium dahliae. Inoculum usually originates in the soil as mycelium or resting structures which can be transmitted by water, wind and mechanical movement of soil. The pathogen can also be introduced on contaminated or infected seed tubers. When soil temperatures get warmer in the spring, dormant spores can enter the plant's vascular system through rootlet infection. Development of the fungus is optimal when soil temperatures are high (22°C to 27°C). Initial symptoms tend to first appear in lower leaves usually in mid to late summer. Interveinal tissue in apical leaflets first turns pale green then yellow. Necrosis is then followed by flagging and death of affected stems. Verticillium has also been known to interact with some Erwinia species.
The following two images are examples of Verticillium Wilt.
7.1.9 Assessing Foreign Varietal Mixtures
Foreign are any potato plant, of any variety, that is not same as the variety for which crop inspection is being conducted on a particular field. The inspector must record total number and percentage of foreign plants but it is not necessary to identify the varieties of these foreign plants.
7.2 Assessing Other Diseases and Insect Damage
During the inspection of a field, the level of severity for Early Blight, Late Blight, Rhizoctonia, Tip Burn, Aphids, and Colorado Potato Beetles, must be recorded on the Inspector's Field Notes (CFIA/ACIA 1298). Section 7.2 serves as a guide in assessing these diseases and insect damage.
Between counts, the inspector must stop periodically to:
- look for insect and disease damage;
- inspect individual plants for aphid infestations by turning over leaf trifoliate;
- inspect fields for insect damage predominantly close to the edge of the field. This is especially important for determining flea beetle and aphid activity; and
- examine leaves and stems for symptoms of fungal infestation.
Determining the Level of Disease and Insect Incidence
Levels of disease and insect incidence are rated and recorded as trace, light, moderate, and severe on the field inspection form as specified on the Table 7-2. Figure 7-2 displays leaf samples with 1%, 10%, 25%, and 50% of area damage, respectively. Determine both the incidence and frequency of the pest in order to determine the overall rating. The incidence is determined by either counting the number of pests or determining the percentage of leaf area affected. The frequency is the percentage of plants affected in the field. The final rating is based on the lowest rating level between the incidence and the frequency.
For example, it is possible to encounter severe incidence on a few plants (>25% leaf area affected) however only 2% of the plants are affected (i.e only a trace frequency). In this case the overriding factor would be the percentage of plants affected (i.e frequency), which would result in reporting the above example as trace.
The following table provides different rating levels for disease and insect incidence.
% of plants affected
5% to 10%
# beetles per plant
2 to 3
4 to 5
# aphids per triplet
2 to 3
4 to 5
% leaf area affected
1% to 5%
6% to 25%
The following image is an example of a key for assessing different severities of leaf damage.
7.2.1 Early Blight (Alternaria solani)
Early Blight is found in most potato growing regions of the world. After over-wintering in the soil on decaying plant matter, Early Blight can usually be found each year in varying degrees of severity. Fungal spores are mostly spread to healthy plants by wind and rain. Very wet and humid growing conditions will favour the development of early blight.
Normally, lower leaves are infected first, becoming more severe when stresses such as other diseases, insect damage or nutrient deficiency affect the crop. When the infestation is severe, both stems and tubers may be affected. The disease usually first appears as small, brown, pinhead-like dots on older leaves. These lesions are circular, 3-10 mm across and consist of concentric rings of dead tissue. Lesions become angular in shape when their expansion becomes limited by large leaf veins. Leaf loss in heavily infected crops, particularly during prolonged wet conditions, may cause sufficient loss of leaf area and subsequently reduce crop yields. As the disease spreads, lesions appear on the upper leaves and on the stems, however infected leaves usually remain attached to the plant.
The following four images are examples of Early Blight.
7.2.2 Late Blight (Phytophthora infestans)
Late Blight (Phytophthora infestans) over winters on seed potato tubers in storage and plant debris left in the field. It begins to spread once temperatures are sufficiently warm to allow for production of spores. Initial symptoms usually appear shortly after flowering, following warm and wet or humid weather. Ideal conditions for late blight development include; high humidity, warm nights (10-15°C) and cool daytime temperatures (10-21°C). Once late blight begins to spread, it can be extremely destructive, destroying entire fields if left unchecked. Inspectors should note that late blight spreads through mechanical means as well as through rain and wind. Efforts should be made to avoid spreading the disease while conducting inspections.
Symptoms usually develop 6 to 8 weeks after planting depending on initial inoculum amount and environmental conditions. Dark green, water-soaked leaf tips will become dark brown and brittle within 2 days. Especially on dewy mornings, lesion edges found on the underside of infected leaves will show a fluffy white mycelium. Late Blight infected areas of leaves will cross major veins, whereas Early Blight will not. If infected seed is planted, symptoms can appear on stems and young tissues. When infections occur at the base of the plant, the presence of mycelial growth may help in distinguishing late blight from blackleg.
The following four images are examples of Late Blight.
7.2.3 Rhizoctonia (Rhizoctonia solani)
Rhizoctonia solaniis a very common fungus to most potato growing regions of the world. It over winters primarily as sclerotia, which are structures that protect dormant spores, and can be found on the surface of harvested tubers as well as on decaying plant matter in soil. Rhizoctonia development is particularly favourable in cool, wet spring conditions. When infected seed is planted, lesions ranging from reddish to dark brown may develop on sprouts and young stems, and as the disease progresses, sprouts and stems may be pinched off by the infection, resulting in uneven stands following emergence.
Mid and late season infections may result in dark brown cankers on stems which may affect the vascular system leading to the production of aerial tubers in the leaf axils. Other common above ground symptoms may occur, including stunting, swollen stems, chlorosis, rolling of leaflet tips and purple pigmentation of leaves. Late in the season, the fungus produces a white mycelium on the stems just above the soil line.
The following five images are examples of Rhizoctonia.
7.2.4 Tip Burn
Tip burn is a non-pathological condition of the leaves which occurs in many parts of the country and may be confused with early blight. The tips and edges of the leaves turn brown and areas soon become hard and brittle. Tip burning may occur at any time during the crop season and is generally caused by unfavourable conditions surrounding the plant. Stretches of cloudy and damp weather followed by several hot and bright days may result in the burning of the foliage. This is particularly pronounced on soils which hold a low percentage of moisture. When the weather is cloudy and damp the tissues of the potato become engorged with water and weakened. If followed by hot, dry sunny periods, there is a rapid transpiration of the moisture out of the leaf tissues which may occur faster than the water from the roots can reach the leaf. If this continues for any length of time the weaker tissue can collapse, die and dry up. Tip burn may also occur as a result of long periods of dry weather.
The following image is an up-close example of a leaf with tip burn; the point of the leaf has become brown and brittle with the rest remaining green.
The main concern associated with the presence of aphids is their capacity to transmit viral diseases from one plant to the other, notably PVY, PLRV, PVA and PVS. There is tremendous diversity in aphid species as well as aphid host species. Potato crops usually host potato, buckthorn, foxglove and green peach aphids. These soft-bodied insects tend to use plant leaves as feeding sites to access plant sap.
Aphids occur in both wingless and winged forms, and over winter as eggs. In the spring, eggs hatch and wingless aphids start immediately feeding and reproducing without mating; they spawn live wingless individuals. Dense colonies consist of thousands of individuals who collectively weaken plants. In some cases a sticky film of honeydew will cover leaves, and circular patterns of dead plants may be observed in the field. When populations become too dense, winged aphids are produced which migrate to nearby host plants where new colonies are established. As the host crop matures and days become shorter, sexual reproduction produces eggs for the next growing season.
The bottom third of potato plants is their preferred location, the exception being the potato aphids which are often found on the top half of the plant where they prefer feeding on the underside of leaves.
The following three images are examples of Wingless Aphids and a cluster of aphids.
7.2.6 Colorado Potato Beetle (Leptinotarsa decemlineata)
The Colorado Potato Beetle (CPB) is a common insect pest found in many potato producing areas including Canada, with the exception of Newfoundland and Labrador. When spring temperatures rise, adults emerge over a period of 4 to 6 weeks from fields previously planted with potatoes. Immediately after emergence, first generation beetles walk towards the nearest emerging potato crop and start eating. Mating and egg laying occur shortly thereafter.
Females may lay up to 400 eggs over a 4-5 week period. Eggs are yellow/orange, shaped like a tiny grain of rice and are deposited in masses of 25-40 eggs mostly on the underside of leaves. They will turn to a darker colour as they mature and hatch within 4-9 days. Larval development occurs over a period of 10 to 20 days, depending on temperatures and rainfall. Once the 4th instar (final larval development stage) reaches maturity, larvae will drop to the ground, burrow 5-10 cm deep, pupate and emerge as adults 5-9 days later. Summers in many areas of Canada are warm enough to allow for two generations of CPB. Cooler regions will have one to two generations depending on temperature during the growing season.
Typical feeding damage observed will primarily be defoliated plants, which can be severe if populations of CPB are high, notably on field edges. CPB is not known to be a vector of potato plant pathogens, although it appears likely that mechanical transmission of propagative material such as spores could occur.
The following four images are examples of the Colorado Potato Beetle as an adult, as larvae, as egg masses and hatched 1st instar larvae, and in an example of defoliation.
7.3 Assessing Stand, Vigour and Cultivation
During the course of the inspection, the stand, the vigour and the cultivation of the crop will need to be rated. Stand, vigour, and cultivation are rated as: A= Excellent, B= Good, C= Fair and D= Poor. These are subjective ratings and a field will not fail as a result of these ratings. These categories are valuable for inspectors, producers, and buyers to determine if crop characteristics are due to seed quality problems, a result of natural conditions or crop management. For example, if one individual lot is planted in several fields in different areas and has reduced vigour in all of these fields it may indicate another underlying problem, leading to further investigation.
Stand refers to overall uniformity of the plants in the field (e.g. in colour, height, etc.) combined with the percentage of plant emergence. An excellent stand would show a very even and complete emergence with very few misses in a row.
Vigour is measured by observing the intensity of plant growth in the field. An excellent field should show lush new growth with even colour. In cases where the crop is performing poorly, possibly attributed to drought, variable fertility, herbicide injury or poor quality seed (physiologically aged, chilled, bruised, small seed pieces), the crop will be given a lower vigour rating.
Cultivation is the condition of the field in relation to tillage and weed control. An excellent seed field should be free of weeds and the plants are well hilled with loose friable soil.
Any disease or anomaly, other than those mentioned above that is encountered during the inspection process should also be noted in each of remarks sections in the Inspector's Field Notes (CFIA/ACIA 1298) and the Report of Field Inspection (CFIA/ACIA 1284).
7.4 Field Inspection Tips
The following are a few inspection techniques or tips which may assist an inspector in increasing her/his accuracy in the assessment of a seed potato crop.
- An inspector should have filled out grower name, field number, variety, hectares, seed source, minimum counts for each field on Inspector's Field Notes (CFIA/ACIA 1298) prior to walking any field.
- An inspector should try to avoid inspecting rows which are directly at their feet, but rather should view the rows which are one to two rows over from the row next to which they are standing, maintaining the line of sight which allows the inspector to view approximately one to two metres ahead from their pace.
- An inspector should try to ensure that the plants being inspected are completely visible from top to bottom. This is especially important upon first inspection; however this will become difficult as plants mature. Inspectors should pay close attention for symptoms of Potato Leafroll Virus (PLRV) as the expression may be first seen on the bottom of the leaves when infected seed is planted.
- An inspector should attempt to maintain the sun at their back to reduce glare and strain on the eyes. This also helps significantly in being able to see symptoms of disease.
- The inspector should shade suspect plants with either, their body, field book, or hat to more readily view characteristic disease symptoms such as mosaic, interveinal necrosis and mild mottling.
- The inspector may need to physically handle plants to determine the presence and type of disease/stress related problem. For example, PLRV infected plants show lower leaf curling, that is a lighter colour, but the leaves are generally firm and rattle when shaken. Whereas blackleg infected plants may show leaf curling that is a lighter colour but leaves remain soft. This may require the pulling of a few plants to observe other symptoms and determine the cause.
- The inspector should examine suspect plants for the presence of insects, and physiological problems which may be attributed to other related factors. For example, nutrient deficient plants could display symptoms similar to mosaic in contrast to healthy plants. Examine the underside of the lower leaves of plants near edges and throughout the field to determine presence of aphids.
- The inspector should become familiar with the characteristics of the variety being inspected, as some pathogens are capable of expressing themselves very differently on various varieties. For example, mosaic in Hilite Russet, Shepody or Russet Norkotah can be difficult to see, while mosaic found in a variety such as Red Pontiac, Atlantic or Century Russet can express severe symptoms and can lead to plant death.
- Inspectors should remember that varieties can display symptoms of primary and secondary infection during different periods of the growing season. For example, the Goldrush variety may appear disease free early in the season, but symptoms of mosaic may become evident around 80 - 100 days after planting
- Inspectors should take note of areas of potential environmental factors which could lead to disease development (e.g. along hedgerows, and other shaded areas, where moisture lingers on the plants, Late Blight symptoms may be more prevalent).
- Inspectors should determine where the planting was initiated in the field. Varietal mixture and disease spread may be most apparent in this area because planting equipment may not have been properly cleaned. Special attention should be given to these areas.
- Inspectors should stop periodically, look around and validate the variety of the crop, observe the general health and status of the crop and investigate any areas which give indications of pest or disease problems. Unless part of count, the disease levels noted in these areas are not to be incorporated into the count, but should be noted in the remarks section of the Inspector's Field Notes(CFIA/ACIA 1298)and the Report of Field Inspection (CFIA/ACIA 1284).
Appendix 1: Application for Seed Potato Crop Inspection Grower's Declaration (CFIA/ACIA 1317)
Appendix 2: Payment Documentation for Seed Potato Crop Inspection (CFIA/ACIA 5440)
Appendix 3: Disinfection Report (CFIA/ACIA 2415)
Appendix 4: Inspector's Field Notes (CFIA/ACIA 1298; book order form)
Appendix 5: Report of Field Inspection (CFIA/ACIA 1284; book order form)
Appendix 6: Growing Crop Certificate (CFIA/ACIA 1318)
Appendix 7: Revocation of Certification (CFIA/ACIA 2546)
Appendix 8: Regulatory Tolerances for Field Grown Seed Potatoes
|Class||Disease or Varietal Mixture||% on First or any Subsequent Inspection||% on Final Inspection|
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Total all viruses
Total blackleg and wilts
Appendix 9: Photo Credits
Canadian Food Inspection Agency 8,9,10,11,12,13,14,15,16,17,18,19
Ontario Ministry of Agriculture, Food and Rural Affairs
© Queen's Printer for Ontario, 2004. Reproduced with permission.
Publication 823. Potato Field Guide - Insects, Diseases and Defects. (Eugenia Banks) 1, 2a, 2b, 3, 4, 5, 6, 7, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47
North Dakota State University
Gary Secor 24
University of Kentucky
Ric Bessin 44
- Date modified: