RMD-13-04: Consolidated Pest Risk Management Document for pest plants regulated by Canada
Appendix 4B: Risk Management Considerations for Centaurea solstitialis (yellowstar-thistle)

• Values at Risk
• Potential Mitigation Measures for Natural Means of Dispersal
• Potential Mitigation Measures for Intentional Introduction Pathways
• Potential Mitigation Measures for Non-intentional Introduction Pathways

Values at Risk

Rangelands: Rangelands are important ecosystems that provide an abundance and variety of products, such as browse and forage for both wild and domesticated animals and wood fibre. Rangelands also provide drinking water, habitat for wildlife, biodiversity, nutrient cycling and recreational opportunities (Horton 1996). Centaurea solstitialis has the ability to invade rangelands, reducing their native biodiversity, wildlife habitat and forage and affecting the natural water cycle. One of the most common and profitable uses of rangeland is livestock grazing. Table 11 shows the number of cattle and calves, sheep and lambs and horses and ponies in areas of B.C. in hardiness zones five to nine. Of concern is that Centaurea solstitialis is toxic to horses if consumed in large amounts and can interfere with livestock grazing and is recognized as one of the "worst weeds in the West" by the Centre for Invasive Plant Management (CIPM 2009).

Potential Mitigation Measures for Natural Means of Dispersal

Natural dispersal is a possible pathway of entry of Centaurea solstitialis into Canada, particularly into British Columbia. Currently, there are four bordering counties in Washington, one bordering county in Idaho and one bordering county in Montana (adjacent to B.C.) that are infested with the weed (USDA-NRCS 2009). It is listed as a Class B Noxious Weed in the State of Washington (NWCB 2009), a noxious weed in Idaho on the Statewide Containment List (ISDA 2009) and a Category 3 noxious weed in Montana (MDA 2009). In Washington and Idaho, the goal is to prevent the spread of existing populations and the establishment of new populations, but not necessarily eradication. In Montana, a management criterion of Category 3 noxious weeds includes awareness and education, early detection and immediate action to eradicate infestations. Depending on how close existing populations are to the border, these programs could reduce the risk of Centaurea solstitialis naturally dispersing into Canada. It is also regulated as a noxious weed under the B.C. Weed Control Act, which requires all land occupiers to control designated noxious plants if found on their property (BCMAL 2002).

As there are populations of Centaurea solstitialis in U.S. counties adjacent to B.C., it is recommended that an early detection and rapid response (EDRR) program should be employed by the province.

Source: Statistics Canada, 2007

Note: data is based on Census Agricultural Regions and Census Divisions, some of which extend beyond hardiness zone 5.

Potential Mitigation Measures for Intentional Introduction Pathways

No intentional introduction pathways for Centaurea solstitialis were identified. Although no mitigation measures are currently required, this pathway will still be regulated under the Plant Protection Act if this species is placed on the List of Pests Regulated by Canada (CFIA 2009).

Potential Mitigation Measures for Non-intentional Introduction Pathways

Field Crops Not Intended for Propagation

Previous imports

It is unknown which grain commodities could be potentially contaminated with seed of Centaurea solstitialis, but the weed has been noted to affect cereal production.

Potential risk mitigation measures

Regulate Centaurea solstitialis as a quarantine pest under the Plant Protection Act and add this species to the List of Pests Regulated by Canada (CFIA 2009) in order to:

• Prevent the importation, movement, and cultivation of this species in Canada.
• Enable inspectors to take appropriate action for the purposes of eradicating the pest or preventing its spread ^{Footnote 1}.
• Regulatory actions under the Plant Protection Act could include one or more of the following:
  • Exporters could be required to provide a Phytosanitary Certificate with or without an Additional Declaration stating freedom from Centaurea solstitialis.
  • Recognition of Pest Free Areas – if Centaurea solstitialis can be shown to be absent in the area from which the field crop product was propagated, then risk is negligible and additional phytosanitary requirements may be waived.
  • An import permit indicating specific import requirements and conditions for the pest status, handling and use of the commodity could be required. It is the importer's responsibility to apply for and obtain the permit.
  • Provisions for importation of grain contaminated with Centaurea solstitialis for research, processing, industrial or educational uses under a section 43 Permit to Import on a case-by-case basis.
  • End uses impact risk and may therefore impact required risk mitigation measures. Phytosanitary measures may be waived for those commodities that have been treated or processed such that the risk of introduction of Centaurea solstitialis has been reduced to an acceptable level.

All risk mitigation measures for field crop commodities containing Centaurea solstitialis must be taken with consideration for requirements/measures for pests other than plants (e.g. pathogens and insects).

Trade implications

• Exporting countries may have to devote resources towards inspection and issuance of Phytosanitary Certificates. Laboratories in foreign countries will need to be able to identify seeds of Centaurea solstitialis. Exporters will need to ensure freedom of Centaurea solstitialis in field crop shipments; otherwise the CFIA can refuse entry.
• Potential for reduction and/or loss of some import markets for Canada should exporting countries be unable to meet proposed phytosanitary requirements.
• Not controlling import and spread of the species may result in infestations of field crops for export; if the importing country prohibits that species, market access for Canadian commodities could be compromised.
• Canadian regulation will facilitate trade with those countries and states which have established regulatory control of Centaurea solstitialis.

Cost-effectiveness and Feasibility

• Resources will be needed by the CFIA for marketplace monitoring and sampling, inspector training, and communication material development.
• Seeds could be screened out of grain lots, depending on the size of the contaminated grain. The seeds are on average 2.5 mm long, 1-1.2 mm wide and 0.5 mm thick. It may be more difficult to clean small-seeded crop kinds. Grain can be cleaned prior to export to remove contaminant seeds.
• Field inspections or laboratory testing in the exporting country could be used to ensure freedom from Centaurea solstitialis.
• A determination of which grains are more prone to contamination of Centaurea solstitialis would be useful to have a more targeted approach for this pathway.

Seed

Two specimens of Centaurea solstitialis were collected in a hay field in Campbellford, Ontario in 1971, prior to the listing of this species on the Weed Seeds Order in 1986.

• The Seed Science and Technology Section of the CFIA Saskatoon laboratory maintains a record of contaminants found through marketplace monitoring of domestic and imported seed and Centaurea solstitialis has not previously been recorded as a seed contaminant.
• From 2006 to 2008, an average of approximately $4.2 million per year or 852,000 kilograms of alfalfa seed was imported from countries where Centaurea solstitialis is present (Statistics Canada 2009). The majority of these imports (approximately 90%) were from infested states in the U.S. (Appendix 4D), with the highest volume arriving from Idaho. An average of approximately $3.1 million worth (574,000 kilograms) of alfalfa seed was imported from Idaho from 2006 to 2008 (Statistics Canada 2009).
• The level of risk associated with imports of alfalfa seed into Canada is relatively low since Centaurea solstitialis has been listed on the Weed Seeds Order since 1986. Although 84% of alfalfa seed imports originate from countries where the weed is present (Industry Canada 2009), exporting countries are required to screen seed shipments to ensure freedom from Centaurea solstitialis.

Previous imports

It is unknown which grain commodities could be potentially contaminated with seed of Centaurea solstitialis, but the weed has been noted to affect cereal production.

Potential risk mitigation measures

• Continue to regulate Centaurea solstitialis as a prohibited noxious weed (Class 1 ^{Footnote 2} ) under the Weed Seeds Order of the Seeds Act ^{Footnote 3}.
• All imported and domestic seed lots must be free of prohibited noxious weed seeds. Imported seed lots require a certificate of analysis stating Centaurea solstitialis is absent from the seed lot before being imported.
• Regulate Centaurea solstitialis as a quarantine pest under the Plant Protection Act.
• Add this species to the List of Pests Regulated by Canada (CFIA 2009) in order to prevent the importation, movement, and cultivation of this species in Canada.
• Enable inspectors to take appropriate action for the purposes of eradicating the pest or preventing its spread.

Regulatory actions under the Plant Protection Act could include one or more of the following:

• Exporters could be required to provide a Phytosanitary Certificate with or without an Additional Declaration stating freedom from Centaurea solstitialis.
• Requirement for a Permit to Import indicating specific import requirements and conditions, handling and use of the commodity.
• Exceptions may be made for the importation of devitalized seed, preserved specimens for scientific research purposes by recognized herbaria and research facilities and the importation of seed for research in containment facilities.
• Recognition of Pest Free Areas – if Centaurea solstitialis can be shown to be absent from the area from which the seed was harvested, then risk is negligible and additional phytosanitary requirements may be waived.
• Recognition of foreign government phytosanitary noxious weed certification in countries or states of origin. This may allow for additional phytosanitary requirements to be waived.

Trade implications

• Exporting countries currently devote resources towards inspection of seed lots and issuance of Phytosanitary Certificates. Laboratories in foreign countries need to be able to identify seeds of Centaurea solstitialis within a seed sample. Exporters currently need to ensure freedom of Centaurea solstitialis in seed lots, otherwise the CFIA can refuse entry.
• Since Centaurea solstitialis is already listed as a prohibited noxious weed, no further trade implications are expected.
• Lack of Canadian regulation could compromise market access for Canadian commodities to those countries that regulate Centaurea solstitialis, should this species become established in Canada.
• Canadian regulation facilitates trade with states in the U.S. that regulate C. solstitialis (see Appendix 4A section III - Current Regulatory Status). Canada exported approximately $28 million worth (65% of the total value exported) of alfalfa seed to these states in 2008 (Industry Canada, 2009).

Cost-effectiveness and Feasibility

• The CFIA Seed Program is already in place to prevent the entry of prohibited noxious weeds, including Centaurea solstitialis. The CFIA monitors compliance with the Canadian standards through the Marketplace Monitoring Program ^{Footnote 4}.
• Seed can be easily identified by trained seed analysts.
• Prior to export, seed is typically cleaned to remove contaminant seeds.
• Seeds of Centaurea solstitialis can be readily screened out of seed lots. This should be done in the exporting country.

Hay and Straw

Previous imports

• From 2006 to 2008, an average value of approximately $12.2 million per year of hay and straw was imported from countries and U.S. states where this weed is present. This represents 97% of the total value of hay and straw coming into Canada (Industry Canada 2009).
• The majority of hay and straw is exported from the State of Washington. In 2008, $10.5 million worth of hay and straw was imported into Canada from this state (Industry Canada 2009).
• Due to the high percentage of hay and straw coming from places infested with Centaurea solstitialis, the risk associated with this pathway is relatively high.

Potential risk mitigation measures

Regulate Centaurea solstitialis under the Plant Protection Act as a quarantine pest by placing it on the List of Pests Regulated by Canada (CFIA 2009) in order to:

• Prevent the importation, movement, and cultivation of this species in Canada.
• Enable inspectors to take appropriate action for the purposes of eradicating the pest or preventing its spread ^{Footnote 5}.
• Regulatory actions under the Plant Protection Act could include one or more of the following:
  • Exporters could be required to obtain a Phytosanitary Certificate with or without an Additional Declaration stating freedom from Centaurea solstitialis.
  • Requirement for a Permit to Import indicating specific import requirements and conditions for the pest status, handling and use of the commodity. It is the importer's responsibility to apply for and obtain the permit.
  • Recognition of Pest Free Areas – if it can be shown to be absent from the area from which the hay or straw was harvested, then risk is negligible and additional phytosanitary requirements may be waived.
  • Requirement for heat treatment or pelletization for hay or straw intended for use as a biofuel stock.

Trade implications

• Exporting countries will need to devote resources towards inspection of hay and straw commodities and issuance of Phytosanitary Certificates. Inspectors in foreign countries need to be able to identify seeds that could become associated with hay and straw. Pre-harvest field inspections may be the most feasible option to ensure pest freedom. Exporters need to ensure freedom of Centaurea solstitialis in hay and straw, otherwise the CFIA can refuse entry.
• Since 97% of hay and straw imports come from U.S. (mostly Washington) where Centaurea solstitialis is invasive, there could be significant market losses of this commodity if it is found to be contaminated.
• Regulation under the Plant Protection Act will secure the export of hay and straw (value of approximately $5.5 million in 2008; Industry Canada 2009) to states where it is regulated.

Cost-effectiveness and Feasibility

• Resources will be needed by the CFIA for marketplace monitoring and sampling, inspector training, and communication material development.

Livestock

Previous imports

• Between 2004 and 2008, approximately 22,000 live horses, assess, bovine animals, swine, sheep and goats for reproduction were imported into Canada.
• Just over half of the imported livestock came from the eastern U.S., where populations of Centaurea solstitialis have not been able to establish.
• The risk associated with the livestock pathway is relatively low due to the small number of animals for reproduction being imported into Canada from places where Centaurea solstitialis is established.

Potential risk mitigation measures

• All regulated animals (including livestock) receive inspection upon their arrival in Canada either by the Canada Border Services Agency (CBSA) or the CFIA according to the Animal Health Directive APHD-DSAE-IE-2004-6-2 (CFIA 2008). This inspection could include a visual check (e.g. for ectoparasites) of the animals. A visual check for plant material could be conducted at this time. Inspection for plant material could be targeted at those animals originating from places infested with Centaurea solstitialis.
• An awareness campaign targeted toward livestock exporters on the CFIA website could be put in place. It would encourage people bringing livestock into the country to ensure their animals are cleaned and free from plant material, particularly seeds.

Trade implications

Exporters are already required to undergo inspection of livestock at the border.

Cost-effectiveness and Feasibility

• CBSA officials, veterinarians or animal health inspectors already perform inspection of livestock entering Canada. Integration of plant material inspection into routine veterinarian checks could be done in order to reduce time and costs.
• Seeds have pappus bristles that are barbed that enable them to adhere to livestock. It may be difficult to detect small seeds, especially on animals with long hair. The time and cost commitment may be too great to control this pathway in this manner.
• Resources will be needed by the CFIA for the development of communication material should a public awareness campaign be put in place.

Vehicles and Used Farm Machinery

Previous imports

• A considerable number of vehicles cross the Canada-U.S. border every year.
• Information is not available on the number of imported used farm machinery or harvesting equipment used in custom combining operations.

Potential Risk mitigation measures

Enforcement of the Directive 95-26: "Phytosanitary requirements of soil and related matter and for items contaminated with soil and related matter" (CFIA 2008).

In 2003, CBSA assumed responsibility for the initial import inspection services in respect to the Acts and Regulations administered by the CFIA to the extent that they are applicable at Canadian border points. The inspection of goods that may be contaminated with soil are among the responsibilities that were transferred to the CBSA in 2003. The Food, Plant and Animals Programs Section of the CBSA is currently finalizing its Standard Operating Procedures (SOP) concerning the "Inspection of Imported Goods Potentially Contaminated with Soil." This SOP provides the CBSA's Border Services Officers with formal procedures for the inspection and disposition of goods that may be contaminated with soil, including used agricultural machinery and vehicles.

Nursery Stock with Soil

There are two documented references of Centaurea solstitialis being found in gardens or landscaped areas. The references indicate that the pest plant may be introduced as an ornamental plant or as a root ball of shrubs or trees.

Previous imports

• The total value of imports of nursery stock was approximately $173 million in 2008 ^{Footnote 6}. Approximately 78% of this value came from states in the U.S. where Centaurea solstitialis is present (Industry Canada 2009).
• While soil from the non-continental U.S. is prohibited as per Directive D-95-26: Phytosanitary requirements of soil and related matter and for items contaminated with soil and related matter, soil associated with nursery stock from the continental U.S is permitted in most cases. It is not possible to determine the amount of nursery stock from the continental U.S. arriving with soil.

Potential Risk mitigation measures

Regulate Centaurea solstitialis under the Plant Protection Act as a quarantine pest and add it to the List of Pests Regulated by Canada in order to:

• Prevent the importation, movement, and cultivation of this species in Canada
• Enable inspectors to take appropriate action for the purposes of eradicating the pest or preventing its spread.

Regulatory actions could include one or more of the following:

• Requirement for exporters to obtain a Phytosanitary Certificate with or without an Additional Declaration stating freedom from Centaurea solstitialis. Centaurea solstitialis could be added to Appendix 6 of D-08-04: Conditions for importation from the continental United States of plant material (other than potatoes) in association with soil and related matter. All soil and related matter in association with plants requires a Phytosanitary Certificate stating freedom from pests named in this appendix.
• Requirement for nursery stock imported from areas infested with Centaurea solstitialis to enter Canada only after the importer obtains a CFIA issued Permit to Import indicating specific import requirements and conditions for pest status, handling and use of the commodity. Prior to the issuance of a Permit to Import, a facility inspection by the CFIA and verification of the importer's ability to meet permit requirements may be required. It is the importer's responsibility to apply for and obtain a Permit to Import.
• Recognition of Pest Free Areas; if the exporting country shows Centaurea solstitialis to be absent from the area from which the nursery stock is produced, then additional phytosanitary requirements may be waived.
• Recognition of nursery certification programs.

Trade implications

• Potential for reduction and/or loss of some import markets for Canada should exporting countries be unable to meet proposed phytosanitary requirements. Since 78% of nursery stock imports originate from infested areas of the U.S., there could be significant market losses of this commodity if Canadian import requirements cannot be met.
• The exporting country may have to devote resources to establish pest-free areas of production and the issuance of Phytosanitary Certificates.

Cost-effectiveness and Feasibility

Phytosanitary Certificates are currently issued by exporting countries for nursery stock and exporting countries currently comply with the phytosanitary requirements set out in D-95-26, including the pest-free area.

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