D- 95-18: Seed Potato Certification Program - Investigation Procedure after Clavibacter michiganensis Subsp. sepedonicus Has Been Detected on a Seed Potato Farming Unit

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Effective Date: June 15, 2011
(4th Revision)

Subject

This directive contains the guidelines for the investigative procedure that must be followed upon the detection of Clavibacter michiganensis subsp. sepedonicus (Spieckermann & Kothoff 1914) Davis, Gillaspies, Vidaver & Harris 1984 (C. m. sepedonicus), on a seed potato farm unit.

This directive has been revised to update the review date, as well as minor administrative changes. The content of this directive has not changed.

Table of Contents

Review

This directive will be reviewed every three years. For further information or clarification, please contact the Canadian Food Inspection Agency (CFIA).

Endorsement

Approved by: Chief, Plant Health Officer

Amendment Record

Amendments to this directive will be dated and distributed as outlined in the distribution below.

Distribution

  1. Directive mail list (Regions, PHRA, USDA)
  2. Provincial Government, Industry (determined by Author)
  3. National Industry Organizations (determined by Author)
  4. Internet

Introduction

This directive deals exclusively with the identification of potato lots or crops, sampling, testing and notification requirements, and documentation needed when the presence of C. m. sepedonicus has been confirmed on a seed potato farm unit or when notification of an interception from foreign plant protection officials has been received. The investigation is limited to all lots and crops, including the ones not entered for, or rejected from, certification, produced on seed potato farm units. Investigative actions beyond seed producing farm units do not fall under the CFIA legislated mandate and may be carried out by provincial or growers' association's representatives depending on their respective mandate. Additionally, this directive provides guidance on the sharing of sensitive information needed by provincial government and growers' association's representatives to deliver their mandates.

The pathogen C. m. sepedonicus is the causal agent of Bacterial Ring Rot disease. It is a serious pest that can infect potatoes and cause extensive damage to a potato crop. Under the Seeds Act and Regulations there is a zero tolerance for C. m. sepedonicus and a mandatory laboratory testing program is in place to maintain the health status of Canadian seed potato stocks. Details of the routine domestic testing program are covered in Directive D-97-12.

For disease control and possible eradication of C. m. sepedonicus, follow up actions are needed once the pathogen and/or the disease has been detected in seed or ware potatoes (means potatoes not certified as seed, (e.g. table stock and processing potatoes)) produced on a seed potato farm unit. Each individual case must be followed up to contain the infected stocks and determine, whenever possible, the source of infection. Additionally, necessary precautions must be taken to prevent any further spread. It is therefore important to work closely with provincial and growers' association representatives in order for them to take proper precautions to prevent any further spread and oversee the disposal of infected stocks.

Scope

This directive is intended for the use of the CFIA inspection staff and growers outlining the sampling and testing requirements, notification and documentation needed when the presence of C. m. sepedonicus has been confirmed on a seed potato farm unit.

This directive supersedes D-95-18 (3rd Revision).

Definitions, Abbreviations and Acronyms

Definitions for terms used in the present document can be found in the Plant Health Glossary of Terms.

1.0 General Requirements

1.1 Legislative Authority

Seeds Act R.S., c. S.-8 and amendments 1976-77, c. 28 and 1985, c. 47

Seeds Regulations and their amendments, SOR/91-526, SOR/93-331, SOR/95-179, SOR/95-215, SOR/97-118, SOR/2000-184 and SOR/2002-198

1.2 Regulated Pest

Clavibacter michiganensis subsp. sepedonicus is the pathogen causing bacterial ring rot seed potatoes.

1.3 Regulated Commodity

Potatoes (Solanum tuberosum)

2.0 Specific Requirements

2.1 Regulatory Requirements

A minimum of two seed lots per farm unit and all seed lots sold as Elite II, Elite III, Elite IV and Foundation class must be sampled and tested, annually, for C. m. sepedonicus as described in Directive D-97-12. Additionally, the presence of C. m. sepedonicus can be detected while performing inspection or analysis required to meet domestic and export requirements for certified and non-certified potatoes produced on a seed potato farm unit or during importing countries monitoring activities. Following confirmation by the Charlottetown Laboratory that a crop or a lot produced on a seed farm unit is infected with C. m. sepedonicus follow up actions are required to comply with section 50 (3) (b), 50 (4) (d), 52 (3) and 52 (6) of the Seeds Regulations.

2.2 Grower Notification

When the presence of C. m. sepedonicus has been confirmed by the Charlottetown Laboratory, in potatoes grown on a seed potato farm unit, the grower must be notified by the Regional Program Officer. A laboratory report and a Revocation of Certification (CFIA/ACIA 2546) must accompany the notification. In cases where a Crop Certificate has not yet been issued, the reason for rejection must be specified on the Report of Field Inspection (CFIA/ACIA 1284). All crops or lots that have come in contact with (see section 2.3.2) or were produced on the affected farm unit will lose their seed potato status, cannot be planted on a seed potato farm unit (Federal legislation) and in most Canadian provinces (Provincial legislation). The land used to produce the infected crop(s) or lot(s) must remain free of potatoes for at least two years prior to eligibility for re-entry into the seed potato certification program. Also, cleanup and disinfection of equipment, storage(s), etc. must be done to the satisfaction of CFIA inspectors before consideration for the production of seed potatoes will be given to the owner of the farm unit.

If seed potatoes of the same crop year and originating from the infected farm unit were shipped within Canada, prior to the detection of C. m. sepedonicus, notification must be prepared by the Regional Program Officer at origin to the Area Seed Potato Specialist at destination providing details on decertification of the lot under section 52(6) of the Seeds Regulations. The Area Seed Potato Specialist is responsible for arranging notification of the receiver of the potatoes from the infected farm unit. If any portion of the infected seed lot was shipped as seed outside of Canada, the National Manager, Potato Section will notify the National Plant Protection Organization of the importing country.

2.3 Follow up actions

2.3.1 Notification of an interception by a foreign country plant protection officials

Upon receipt of a notification of an interception of C. m. sepedonicus by a plant protection official of a foreign country, the identified seed lot must be sampled at a rate of at least 2000 tubers, labelled and shipped as specified in section 2.4. Any samples retained in storage from the lot and shipment in question must be totally included in the sample submitted for analysis. In the eventuality tubers from the identified seed lot are no longer available, the National Manager of the potato section will explore the possibility of having intact bags re-exported to Canada and shipped to the address specified under 2.4.4 for testing.

In the eventuality the presence of C. m. sepedonicus is confirmed, the investigation will proceed as specified in the following sections. However, if the results are negative for the presence of C. m. sepedonicus the certification status of the seed lot produced on the farm unit will be maintained.

2.3.2 Determination of potential sources of infection and contamination

The objective of the investigation is to determine the origin of the infection and prevent introduction or further spread into certified seed potatoes. To assist in identification of the source of infection and determine other potentially affected farm units, local inspection personnel must, in discussion with the grower, review the disinfection practices and disinfectant used, planting sequences and assess if any potato handling equipment was shared with other farm units. This information is essential to help determine the source of infection and potential spread and must be forwarded to the Regional Program Officer. It will be analysed and used to determine which investigative actions are required.

Collaboration between Regional Program Officer, Area Seed Potato Specialist, a representative from the Charlottetown Laboratory and a representative from the Potato Section in Headquarters is important in each case. A thorough review of the information gathered during the investigation, along with testing results obtained from seed and ware potatoes (means potatoes not certified as seed, (e.g. table stock and processing potatoes)) grown on the infected farm unit, the sister and contact lots or crops, provides the basis to determine which further actions are required. Appendix 1 provides a flow chart of the testing requirements that must be met once C. m. sepedonicus has been found in potatoes grown on a seed farm unit.

  • When all sister lots or crops are found to be negative it is considered that the seed source was not the cause of the infection. In that case, the investigation should focus on the infected farm unit.
  • When testing results do reveal the presence of C. m. sepedonicus in at least one sister seed lot or crop grown on a different farm unit, the investigation should focus on the farm unit where the seed source was produced.

The investigation should be done on the basis of farm unit(s). Growers managing their seed potato crops as separate farm units, e.g., Nuclear Stock managed separately from other seed potato crops, should have submitted separate Applications for Seed Potato Crop Inspection prior to the specified deadlines, for each farm unit. When separate applications have been submitted by a grower and management practices are in place to prevent contact between farm units, they can be considered separate farm units and investigation should proceed accordingly.

Shipments of seed potatoes from a farm unit under investigation must be suspended until all testing of the lots under investigation is completed and the presence of C. m. sepedonicus is not detected. Preventing any shipments of seed from a farm unit implicated in an investigation is necessary to limit the spread of C. m. sepedonicus in the eventuality that it is present on the farm unit.

Follow-up actions must be carried out in a professional and expedient manner to prevent any spread of the pathogen. Therefore, it is recommended to have all samples from the identified farm units collected and tested within a 2 - 4 week period.

2.3.3 Notification of provincial government and potato growers' association representatives

Provincial government and, as appropriate, potato growers' association representatives, must be informed when C. m. sepedonicus is detected in a seed potato farm unit and kept informed of any developments during the investigation process. The information is provided to the province, and/or potato growers' association and, if appropriate, they may have to investigate commercial farms, outside the CFIA mandate, and apply provincial regulations. Additionally, provincial and potato growers' association representatives are usually involved in the proper disposal of C. m. sepedonicus infected potato stocks and in the clean up and disinfection process.

The notification of provincial government authorities and potato growers' association representatives of the province, in which C. m. sepedonicus was detected, should be done by the Regional Program Officer as soon as possible after the presence of C. m. sepedonicus has been confirmed on a farm unit. The information communicated to the respective organisations will be limited to what is necessary to carry out their respective mandate. Persons receiving the information will be asked to maintain confidentiality within their respective organization and to use it strictly to carry out their respective mandate.

2.3.4 Testing requirements for the infected farm unit, contact farm unit and sister lots or crops

The investigation should initially concentrate on the infected farm unit, the sister seed lots or crops, and any seed lots or crops which may have come in contact with equipment used on the infected farm unit.

A tuber or stem sample from each one of the following potato lots or crops identified for testing must be submitted for analysis:

  • The infected lot or crop will not be re-sampled and tested again.
  • Lots or crops planted from the same seed source as the infected lot or crop (i.e., sister lots) must be traced back. Each sister lot or crop produced on a seed potato farm unit, entered for certification or not, must be sampled at 2000 tubers or stems and submitted for testing.
  • l000 tubers or stems must be tested from all other seed and non-seed lots or crops produced on the infected farm unit.
  • Lots or crops from other farm units that may have come in contact with equipment used on the infected farm unit prior to proper cleanup and disinfection, i.e., custom spray equipment which provides services to several farm units, must be tested at 1000 tubers or stems.

2.3.5 Additional testing which may be required

Seed can be the source of infection. Test results from sister lots or crops are very valuable to establish whether further testing is required to rule out possible contamination of other seed lots or crops.

There is no need to initiate testing on the farm unit which supplied the seed (see section 2.3.2) or the farm units which received seed from the infected unit, if none of the sister seed lots or crops were determined to be infected, unless there is no sister seed lot available for sampling and testing.

2.3.5.1 Seed source from another farm unit

The following testing must be done at the specified rate only when the infected seed lot or crop was planted with seed received from another farm unit and:

  • there is no sister seed lot or crop available; or
  • at least one sister seed lot or crop was determined to be infected with C. m. sepedonicus
    • 1000 tubers or stems from all lots or crops, produced or planted, with seed potatoes originating from the farm unit which supplied the seed source for the production of the positive lot or crop.
2.3.5.2 Seed source from the infected farm unit

If the infected lot or crop was planted with the grower's own seed, the following testing on seed farm unit is required when there is no sister seed lot or crop, or at least one sister seed lot or crop was determined to be infected with C. m. sepedonicus:

  • 1000 tubers or stems from each lot or crop produced from seed potatoes supplied by the infected farm unit. It only applies to lots or crops that are the direct progeny and grown or produced on a seed farm unit, not the ones that have been produced for more than one generation.

2.4 Sample Collection and Submission

All samples collected to comply with this directive are considered investigative samples and must be collected by or under the supervision of a CFIA inspector and shipped as specified in section 2.4.4. Samples collected for the routine domestic testing program and tested in CFIA accredited laboratories are not to be considered as investigative samples.

2.4.1 Stem sampling

Stem sampling must be done as prescribed in section 3.3 of Directive D-97-12. Plants expressing Bacterial Ring Rot disease symptoms should be collected and packaged separately.

2.4.2 Tuber sampling

Tubers should be collected randomly to represent the entire seed lot. Any tubers showing Bacterial Ring Rot disease symptoms should be collected and packaged separately.

Although it is preferable to send whole tuber samples for testing, in certain circumstances, tuber cores may be considered to be quite valuable to the grower. Therefore, it is possible to core the tubers on the farm unit in accordance with the instructions in section 3.4 of Directive D-97-12. Necessary precautions must be taken to avoid any potential cross-contamination of the tubers and samples during the coring process.

2.4.3 Identification

Samples from different potato lots or crops must be submitted in separate bags to maintain sample integrity. When a sample from a lot or crop is submitted in more than one bag the number of bags must be indicated. When a sample is collected over more than one field, it is advisable to submit each portion of the sample in separate bags and identify them accordingly. A Pest Identification Report (CFIA/ACIA 1303) must be completed and sent along with each sample for continuity.

The following information is required on the label affixed to each bag, otherwise the sample will not be tested until correct identification is received:

  • Grower's or corporation name
  • Variety name
  • Certification number or seed source number
  • Class assigned (if applicable)
  • Number of field sample units (i.e. Number of stems or tubers)
  • Date planted (required for stem samples only)
  • Date collected
  • Grower's or representative's signature (not mandatory)
  • Inspector's signature
  • Test for which sample is submitted.

2.4.4 Packaging and shipping

Refer to Directive D-97-12 section 3.5 for instructions on how to package and ship the samples. All the samples collected for investigation purposes must be forwarded to:

Charlottetown Laboratory
93 Mount Edward Road
Charlottetown, PEI
C1A 5T1

2.5 Laboratory Testing and Results

The Regional Program Officer where the sample originated is the contact person for the Charlottetown Laboratory. It is the responsibility of the Regional Program Officer to inform the Charlottetown Laboratory with respect to the expected volume of testing and the time frame for the delivery of the samples.

All investigative samples testing for C. m. sepedonicus are performed by the Charlottetown Laboratory. Results are forwarded to the Regional Program Officer for further distribution and follow up action.

2.6 Final Report

The Regional Program Officer must provide the Area Seed Potato Specialist, the Charlottetown Laboratory and the National Manager, Potato Section with the following documentation within 30 days of the detection of Clavibacter Michiganensis Subsp. Sepedonicus;

  • copy of notification to grower with completed Pest Identification Report (CFIA/ACIA 1303)
  • Revocation of Certification (CFIA/ACIA 2546) or Report of Field Inspection (CFIA/ACIA l284)
  • application for Seed Potato Crop Inspection - Growers Declaration (CFIA/ACIA 1317)
  • a copy of all laboratory reports
  • officer's report, which should cover the following items:
    • background information on the farm unit(s) (previous cases, and seed vs commercial production)
    • management practices (disinfection, planting sequence, sharing of equipment, crop rotation and land rental)
    • investigation results
    • conclusion (difficulties experienced, lots no longer available, possible source of infection, etc.)

3.0 Grower Eligibility

3.1 Provisions

Following an outbreak of Bacterial Ring Rot, C. m. sepedonicus, a grower must:

  • submit in writing, their intention to re-enter the seed potato certification program, to a local office of the CFIA
  • under the supervision of a CFIA inspector, follow the criteria as outlined in the Seed Potato Regulations and Manual, for all appropriate clean-up and disinfection procedures prior to receiving seed potatoes for planting
  • ensure that the land to be planted with seed potatoes was not used to produce Bacterial Ring Rot infected potatoes in the previous two years
  • plant all potato crops on the farm unit with Foundation class seed or better
  • make application for inspection as prescribed under the Seed Potato Regulations, Part II of the Seeds Act. Comply with all elements of the act and regulations as prescribed
  • have a random sample of 1000 tubers or stems taken by a CFIA inspector, for each seed lot produced on the farm unit, in the subsequent three years of seed production
  • submit for testing against C. m. sepedonicus each sample, collected under the supervision of a CFIA inspector, to an accredited laboratory and the Charlottetown Laboratory as prescribed in Directive D-97-12

4.0 Appendices

Appendix 1: Flow Chart for C. m. sepedonicus testing once it has been detected on a seed potato farm unit

Click on image for larger view
Flow Chart: Clavibacter michiganensis sepedonicus testing once it has been detected on a seed potato farm unit. Description follows.

Description of flow chart for Clavibacter michiganensis sepedonicus testing once it has been detected on a seed potato farm unit

The flow chart describes testing for Clavibacter michiganensis sepedonicus once it has been detected on a seed potato farm unit.

The flow chart starts with the box titled Clavibacter michiganensis subspecies Sepedonicus Positive Seed Lot or Crop. From this box, three options are available which are represented by three individual boxes. One or more options may be chosen.

The first option from the initial box of the flow chart is "Test all other potato lots or crops on the affected and contact farm units (1000 tubers or stems each)". If the results are positive, proceed to the beginning of the flow chart and start again. If the results are negative, proceed to the box titled "All lots or crops on affected and contact farm units and sister lots found negative, stop testing". There are no further steps in this branch of the flow chart.

The second option from the initial box of the flow chart is "Test all sister lots (2000 tubers or stems each)". If the results are negative, proceed to the box titled "All lots or crops on affected and contact farm units and sister lots found negative, stop testing". If the results are positive, proceed to the beginning of the flow chart and start again. Then, proceed to one of the following two options:

  1. Seed was provided by another farm unit. All lots or crops produced or planted with seed potatoes originating from the farm unit which supplied the seed source for the production of the positive lot or crop (1000 tubers or stems each) or
  2. Seed was produced on the affected farm unit. Test all lots or crops produced from the seed supplied by the affected farm unit (1000 tubers or stems each).

In both cases, if the results are positive, proceed to the beginning of the flow chart and start again. If the results are negative, proceed to the box titled "All results negative, stop testing". There are no further steps in this branch of the flow chart.

The third option from the initial box of the flow chart is "No sister lots available". Proceed to one of the following two options:

  1. Seed was provided by another farm unit. All lots or crops produced or planted with seed potatoes originating from the farm unit which supplied the seed source for the production of the positive lot or crop (1000 tubers or stems each). or
  2. Seed was produced on the affected farm unit. Test all lots or crops produced from the seed supplied by the affected farm unit (1000 tubers or stems each).

In both cases, if the results are positive, proceed to the beginning of the flow chart and start again. If the results are negative, proceed to the box titled "All results negative, stop testing. There are no further steps in this branch of the flow chart or any other branch of the flow chart.

Note: Provincial government and potato growers' association representatives must be kept informed and may conduct further investigation on commercial units.

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