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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

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).

Table 2: Agricultural lands and production of ruminant animals at risk to be impacted by the spread of Centaurea iberica (Iberian star-thistle)
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)
Ontario157,00052,000220,00034,000
Nova Scotia4,5004,0007,0002,000
British Columbia4,50042,00034,5000
Total:166,00098,000261,50036,000

Table Notes

Table note 2

Areas located in hardiness zone 6 and higher (Agriculture and Agri-Food Canada 2009).

Return to first table note a referrer

Statistics Canada 2001.

Return to first table note b referrer

Figure 3: Canadian total exports of forage seed to Arizona, California, Nevada and Oregon.

Figure 3. Description follows.
Description for Figure 3

This figure shows the total Canadian exports of forage seed (in $'000) to Arizona, California, Nevada and Oregon for the years of 2004 through 2008. This line graph relies that California, Nevada and Arizona have a forage seed export value of less than 5,000 while Oregon and the overall total increase steadily surpassing 15,000 for the four years with a notable increase in 2007 when it topped 25,000. Seed of clover, alfalfa, fescue, ray-grass (Lolium multiflorum and Lolium perenne) and other forage, except beet and Kentucky grass (Poa pratensis).

Source: Statistics Canada in Industry Canada 2009

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).

Figure 4: Imports of clover seed from countries and areas where Centaurea iberica (Iberian star-thistle) is present.

Figure 4. Description follows.
Description for Figure 4:

This figure shows the imports of clover seeds from countries and areas where Centaurea iberica is present for the years of 2006, 2007 and 2008. This bar graph relies the import values for China (light green), U.S. California (black), U.S. Washington (red and white strips), and U.S. Oregon (turquoise). This graph shows that the predominant import values (over 800,000) comes from U.S. Oregon; moreover, the import values have been rising steadily and the remaining of the actors accounts for less than 10% of the imports for those years.

Source: Statistics Canada in 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.

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):

Trade implications

Cost-effectiveness and feasibility

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.

Figure 5: Number of live animals intended for reproduction imported from countries where Centaurea iberica (Iberian star-thistle) is present

Figure 5. Description follows.
Description for Figure 5:

This figure displays, through the use of a bar graph, the number of live animals intended for reproduction that were imported from countries where Centaurea iberica is present. The United States's value is indicated using light blue and other countries using black. Cattle, in the U.S., has approximately 500 and is nonexistent in other counties. While goats, sheep and hog have hardly any visible presence in both the U.S. and in other countries on the table. Horses, on the other hand, surpass 5,000 in other countries while surpassing 1,000 in the U.S.

Source: CFIA internal data

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

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