RMD-13-04: Consolidated Pest Risk Management Document for pest plants regulated by Canada
Appendix 14B: Risk Management Considerations for Solanum elaeagnifolium (silverleaf nightshade)

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Values at Risk

Several crops are affected by Solanum elaeagnifolium worldwide, the most important being cereals (wheat, sorghum and maize), alfalfa (lucerne) and cotton. In Australia and the U.S., wheat production losses have been as high as 50%. A 2007 survey of farmers in Australia showed that Solanum elaeagnifolium has spread across the wheat belt of Victoria, New South Wales and South Australia. On average, the total farm cost for the weed was $1,730 (AUD) per year for control and $7,786 (AUD) per year in production losses (Kidston et al. 2006). Sorghum losses have ranged from 4-10% under optimal moisture conditions (CAB International, 2007; Sforza and Jones 2007).

The amount of land in each province in hardiness zones 5-9 that are planted with the species most affected by Solanum elaeagnifolium. The Province of Ontario has the greatest amount of crop area that could be impacted. In 2008, Ontario counties in hardiness zones 5 and 6 produced approximately 12 million bushels of wheat (OMAFRA, 2009) Maize production was approximately 48 million bushels in 2008 in Ontario counties (OMAFRA, 2009). Sorghum production in the respective provinces is considered marginal. A total of 22 hectares of organic sorghum was produced in Canada in 2005, with 15 hectares originating from provinces where Solanum elaeagnifolium could establish (Macey 2006).

Table 2: Pathways for Solanum elaeagnifolium
Type of Commodity
(Pathways)
Introduction Previous Imports Potential Risk Mitigation Measures Trade Implications Cost Effectiveness & Feasibility
Seed Intentional No data available
  • Regulate under the WSO
  • Regulate under the PPA
Market loss for exploring countries would be minimal Seed Program already in place
SeedUnintentional
(as a contaminant)
This species has not previously been recorded in imported and Canadian seeds samples
Level of risk is high since maize and forage plants originate primarily from areas where this species is present
  • Regulate under the WSO
  • Regulate under the PPA
  • Will facilitate seed trade with the 19 states where this species is regulated
  • Potential reduction or loss of some import markets for Canada
  • Seed Program already in place
  • Easily identified by trained analysts
Field crops not intended for propagation Unintentional 300,000 tonnes of wheat, sorghum, maize and soybeans from countires with Solanum eleagnifolium were import in 2008 Regulate under the PPAPotential for reduction or loss of some import markets for Canada if physanitary requimrents can not be met. Resources will be needed for marketplace monitoring
Hay and Straw Unintentional Hay and straw imports were around $13 million in 2008 (harvested frequently and before weeds produce fruit) Regulate under the PPARegulation of this species will safeguard trade of hay and straw with US, Potential reduction of import markets in Canada Resources will be needed for CFIA marketplace monitoring
Vehicles and Used Farm Machinery Unintentional Considerable volume of vehicles cross US and Canadian border
Information not available on imports of used farm machinery
Enforcement of Directive 95-96: Phytosanitary requirements for soil and related matter, alone or in association with plants   
Nursery Stock with soil Unintentional In 2008, 73% of all nursery stock imports came from countries where this species is present Regulate under the PPAPotential reduction in import market for Canada if exporting countries cannot meet requirements Phytosanitary certificate are currently issued by exporting countries for nursery stock.
Manure Unintentional Data is unavailable Bagged, composted manure regulated by Health of Animals Regulations. There are currently no standards for fresh manure. No trade implications If heating process makes weed seeds inviable, the n this would be a cost effective measure.
Livestock Unintentional Risk associated with livestock pathway is relatively low It is not feasible to implement mitigation measures for this pathway at this time.   

Potential Mitigation Measures for Natural Means of Dispersal

Natural dispersal of Solanum elaeagnifolium seeds by birds, animals or water could cover great distances and this represents a possible pathway of entry into Canada. Currently, populations of the plant in Washington are in counties at the southern margins of the state (USDA-NRCS, 2009). Washington State carries out eradication of Class A weeds as required by law (NWCB, 2009). Oregon and Idaho also have programs to eradicate noxious weeds (ODA, 2009; ISDA, 2005). If these programs are effective, the risk of natural dispersal as a pathway into Canada will decrease.

Since Solanum elaeagnifolium is currently at the southern margins of bordering states, an early detection and rapid response (EDRR) program should be employed such as the framework established in British Columbia. The Invasive Plant Council of BC has approved an EDRR framework that describes the process, steps and stakeholders involved in carrying out an EDRR system in the province (IPCBC, 2007). Early detection can be made possible with the use of atlases already available such as E-flora BC (Klinkenberg 2008) that inventory native, non-native and invasive species.

Potential Mitigation Measures for Intentional Introduction Pathways

Although sources indicate Solanum elaeagnifolium is not currently being sold as an ornamental plant in Canada (CNLA, 2009), further research found two Internet sites with seeds of Solanum elaeagnifolium for sale. While these companies indicate that they will ship to Canada, it is unknown how often, if any, seeds have been brought into Canada through this pathway. The potential for intentional introduction of Solanum elaeagnifolium into Canada is low.

Seed

Previous imports

None known. There is no data available specific to imports of Solanum elaeagnifolium.

Potential risk mitigation measures

Regulate Solanum elaeagnifolium as a prohibited noxious weed (Class 1) under the Weed Seeds Order of the Seeds Act Footnote 1.

Regulate 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:

Regulatory actions under the Plant Protection Act could include the following:

Sufficient information about the use of Solanum elaeagnifolium as a potential crop does not exist. If the proponent, located in Canada, needs to collect more information about the plant (e.g. to generate data for a determination of environmental safety), then confined research field trials under Part V of the Seeds Regulations could be authorized by the Plant Biosafety Office.

Trade Implications

Cost-effectiveness and Feasibility

Potential Mitigation Measures for Non-Intentional Introduction Pathways

Field Crops Not Intended for Propagation

Previous imports

The total volume of wheat, sorghum, maize and soybeans Footnote 6 imported in 2008 from countries where Solanum elaeagnifolium is present was approximately 300,000 metric tonnes (Appendix 14C; Statistics Canada, 2009). The majority of these imports (99.5%) came from infested U.S. states (Industry Canada, 2009).

Potential risk mitigation measures

Regulate Solanum elaeagnifolium as a quarantine pest under the Plant Protection Act and add this species to the List of Pests Regulated by Canada in order to:

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

End uses have an impact on risk and may, therefore, affect 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 Solanum elaeagnifolium has been reduced to an acceptable level.

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

Trade implications

Cost-effectiveness and Feasibility

Seed

Previous imports

Potential risk mitigation measures

Regulate Solanum elaeagnifolium as a prohibited noxious weed (Class 1) under the Weed Seeds Order of the Seeds Act.

Regulate Solanum elaeagnifolium as a quarantine pest under the Plant Protection Act and add this species to the List of Pests Regulated by Canada in order to:

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

Trade implications

Cost-effectiveness and Feasibility

Hay and Straw

Previous imports

Potential risk mitigation measures

Regulate Solanum elaeagnifolium under the Plant Protection Act as a quarantine pest by placing it on the List of Pests Regulated by Canada in order to:

Regulatory actions could include one or more of the following:

Trade implications

Cost-effectiveness and Feasibility

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

Vehicles and Used Farm Machinery

Previous imports

Potential Risk mitigation measures

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

Nursery Stock with Soil

All parts of the root of Solanum elaeagnifolium are capable of forming shoot buds; root fragments only 1 cm long retain the ability to sprout. In addition, sections of taproot can remain viable for up to 15 months (Boyd et al., 1984; Parsons and Cuthbertson, 2001). Root fragments of Solanum elaeagnifolium can contaminate soil in imported nursery stock and establish if planted in suitable growing conditions.

Previous imports

Potential Risk mitigation measures

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

Regulatory actions could include one or more of the following:

Trade implications

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 pest-free areas of production.

Manure

Previous imports

Data is unavailable to determine the total values of manure imports.

Potential risk mitigation measures

Trade implications

No trade implications are expected since regulations are already in place for manure.

Cost-effectiveness and Feasibility

If the heating process does make weed seeds inviable, this provides a cost-effective measure for the manure pathway.

Livestock

Previous imports

Potential risk mitigation measures

It is not feasible to implement mitigation measures for this pathway at this time.

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