RMD-13-04: Consolidated Pest Risk Management Document for pest plants regulated by Canada
Appendix 3B: Risk Management Considerations for Centaurea iberica (Iberian starthistle)
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- 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
Livestock Industry
Centaurea iberica could establish in pastures and fodder crops, and diminish the quality of forage. It is difficult to evaluate the value of forage because the harvest is usually intended to feed livestock on the farm where it is produced. Feed is the largest single cost of a beef operation, accounting for 60% of expenditures (Potter 2004). The increase in cost of production or a decrease in forage quality could directly impact dairy, cattle and sheep farm incomes.
Almost 250,000 ha of pasture and fodder crops are at risk in Canada. This area, mostly located in Southern Ontario, currently feeds around 261,500 cattle (dairy and beef production) and 36'000 sheep and lambs (see Table 2). In 2007, farm cash receipts were worth $410 million for dairy production and $160 million for the beef industry in Southern Ontario (OMAFRA 2006).
Seed Trade
The presence of Centaurea iberica in forage crops in Canada could affect trade of forage seed with the states of Arizona, California, Nevada and Oregon where Centaurea iberica is prohibited. The value of Canadian forage seed exported to these states fluctuates between $14.9 and $28.5 million/year (see figure 3).
Canadian Provinces Table Note a | Hay and fodder crops Table Note b (ha) | Natural and tame pastures Table Note b (ha) | Cattle and calves Table Note b (nb) | Sheep and lambs Table Note b (nb) |
---|---|---|---|---|
Ontario | 157,000 | 52,000 | 220,000 | 34,000 |
Nova Scotia | 4,500 | 4,000 | 7,000 | 2,000 |
British Columbia | 4,500 | 42,000 | 34,500 | 0 |
Total: | 166,000 | 98,000 | 261,500 | 36,000 |
Table Notes
- Table note 2
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Areas located in hardiness zone 6 and higher (Agriculture and Agri-Food Canada 2009).
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Statistics Canada 2001.
Potential Mitigation Measures for Natural Means of Dispersal
Allison (2009) has not identified any risk associated with natural means of dispersal.
Potential Mitigation Measures for Intentional Introduction Pathways
According to Allison (2009), Centaurea iberica is not a cultivated plant. It is not available in Canada as an ornamental (CNLA 2009).
Potential Mitigation Measures for Non-intentional Introduction Pathways
Seed of Clover
Previous imports
For the past ten years, the value of clover seed imported from areas where Centaurea iberica is present fluctuated between $0.8 and $2 million (see Figure 4 and Appendix 3C) (Industry Canada 2009).
Potential risk mitigation measures
Regulate Centaurea iberica as a prohibited noxious weed (Class 1) under the Weed Seeds Order of the Seeds Act Footnote 1.
- This species meets the definitions for Class 1 Footnote 2 species under the Weed Seeds Order
- All imported and domestic seed lots must be free of prohibited noxious weed seeds. Imported seed lots would require a certificate of analysis stating Centaurea iberica is absent from the seed lot before it can be imported.
Regulate Centaurea iberica as a quarantine pest under the Plant Protection Act and add this species to the List of Pests Regulated by Canada (CFIA 2009):
- This could prevent the importation, movement, and cultivation of this species in Canada.
- Exporters of clover seed could be required to obtain a phytosanitary certificate stating freedom from Centaurea iberica.
- The only exceptions would be for the importation of preserved specimens for scientific research purposes by recognized herbaria and research facilities and the importation of seed for research in containment facilities.
- Phytosanitary agreements could be negotiated to certify imports from pest free areas and/or recognize noxious weed certification in countries or states of origin.
Trade implications
- Exporters in other countries will need to devote resources towards inspection of seed lots and issuance of phytosanitary certificates. Laboratories in exporting countries will need to be able to identify seeds of Centaurea iberica within a seed sample. Exporters need to ensure freedom of Centaurea iberica in seed lots, otherwise CFIA can refuse import.
- This measure will facilitate seed trade with the American states of Arizona, California, Nevada and Oregon, where Centaurea iberica is prohibited.
Cost-effectiveness and feasibility
- The CFIA Seed Program is already in place to prevent the entry of prohibited noxious weeds. The CFIA monitors compliance with the Canadian standards through the Marketplace Monitoring Program Footnote 3
- The seeds of Centaurea iberica are easily identified
- Centaurea iberica seeds can be readily screened out of clover seed due to the relatively large size of the seeds (3 to 4 mm long).
Livestock
Previous imports
Since 2004, around 8000 live animals intended for reproduction have been imported into Canada from areas where Centaurea iberica is present (see Figure 5). This represents around 2% of total imports of live animals for reproduction (CFIA internal data).
Potential risk mitigation measures
No mitigation measures needed. The level of risk associated with this pathway is relatively low due to the small number of livestock imported into Canada.
This sampling program helps to ensure that seeds sold in, imported into and exported from Canada meet established standards for quality, including varietal purity and germination, and are labelled so that they are properly represented in the marketplace, and in the case of most agricultural crop varieties, are registered prior to sale in Canada.
Raw Wool and Raw Hides
Previous imports
The total value of raw wool imports was around $3.1 million in 2008; less than 0.1% of that value came from countries and American states where Centaurea iberica is present (Industry Canada 2009).
Potential risk mitigation measures
- No measures are required. Imports at risk are not significant.
- Raw wool and raw hides imported into Canada from all countries require CFIA inspection. It must be free from feces, blood, ectoparasites and dirt (plant and plant parts are considered to be dirt) or it will be refused of entry (Health of Animals Act, Directive AHPD-DSAE-2001-1-1 (CFIA 1990)).
- The vegetative matter is removed from commercial wool by carbonization Footnote 4.
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