RMD-13-04: Consolidated Pest Risk Management Document for pest plants regulated by Canada
Appendix 2A: Pest Risk Assessment Summary for Alopecurus myosuroides (slender foxtail)
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- Identity of Organism
- Organism Status
- Current Regulatory Status
- Probability of Entry
- Probability of Establishment
- Probability of Spread
- Potential Economic Consequences
- Potential Environmental and Social Consequences
- Technical Issues for Consideration
Identity of Organism
Name: Alopecurus myosuroides Huds (family Poaceae, subfamily Pooideae, tribe Poeae) (USDA -ARS 2009)
Synonyms: Alopecurus agrestis L., Alopecurus coerulescens Steud. & Hochst. ex Steud (nom. nud.), Alopecurus purpurascens, Tozzettia agrestis (L.) Bubani (Tropicos 2008)
English common names: Slender foxtail, black grass, black twitch, large foxtail (USDA -ARS 2009)
French common names: Vulpin des champs (USDA-ARS 2009)
Description: Alopecurus myosuroides is an erect, winter annual, tufted grass with reddish-purple panicles, appearing black at a distance. It flowers in early spring (Hubbard 1968; Aldrich-Markham 1992).
Alopecurus myosuroides has been reported to occur in Canada but did not become established, and no evidence was found that it is cultivated in Canada (CFIA 2008; Scoggan 1979). For more information, see under Probability of Entry. Based on this information, it is considered absent from the pest risk assessment area.
Current Regulatory Status
Alopecurus myosuroides is not currently regulated in Canada. Alopecurus myosuroides is not regulated as a federal noxious weed in the U.S. but is regulated by the state of Washington.
Probability of Entry
Alopecurus myosuroides has been accidentally introduced in contaminated grass seed to fields on research stations in Saanichton, BC (1955) and Brandon, MB (1965), but did not become established (Scoggan 1979). The provincial Conservation Data Centers (CDCs) do not consider the species to be established in these two provinces (CFIA 2008).
Alopecurus myosuroides is propagated only by seed. The main pathway for entry into Canada, based on monitoring of seed lots, is as a contaminant in grass seed lots (Table 1).
|Type of pathway||Specific pathways|
Alopecurus myosuroides is an annual that spreads entirely by seed. Wind is the main natural means of dispersal over short distances.
This is an unlikely pathway for entry into Canada, given the current range.
|Intentional introduction||None identified.|
|Unintentional introduction Pathways||
Slender foxtail is an occasional contaminant in lots of grass seed.
This is the most likely pathway for entry into Canada. Based on the CFIA seed laboratory database, Alopecurus myosuroides has been detected in 5 imported grass samples in the past 9 years. As many as 12 seeds were reported from a single sample.
Alopecurus myosuroides could potentially occur as a contaminant in grain lots.
Although the species is a serious weed of winter cereals in Europe, it is very unlikely that Alopecurus myosuroides would occur as a contaminant in processed grains, as it would be readily removed during combining and cleaning. Seeds have not been reported in cereal seed samples in the past 9 years in Canada.
It could also occur in imported hay and straw as contaminant seeds in panicles.
Probability of Establishment
Alopecurus myosuroides is native to northern Africa (n. Algeria, n. Egypt, n. Libya and Tunisia), Asia (Afghanistan, Cyprus, Iran, Iraq, Israel, Jordan, Lebanon, Syria, Turkey, Armenia, Azerbaijan, Georgia, Ciscaucasia, Dagestan, Turkmenistan, Uzbekistan, n. India and Pakistan), and Europe (United Kingdom, Belgium, Germany, Netherlands, Russian Federation, Ukraine, Albania, Bulgaria, Former Yugoslavia, Greece, Italy, Romania, France, Portugal and Spain) (USDA -ARS 2009).
It is widely naturalized in temperate parts of the world, including North America (U.S. and Mexico), South America (Bolivia, Peru, Argentina), China, Australia and New Zealand (Häfliger and Hildemar 1981). It has been widely introduced in the U.S. (see figure 1) as a weed of cultivation (Barkworth 2006).
In Europe, Alopecurus myosuroides grows in moist meadows, deciduous forests, and cultivated or disturbed ground and is a significant weed species in temperate cereal crops (Barkworth 2006). In the U.S., the species is reported mostly from cultivated fields (Barkworth 2006) but it is now commonly found in wetter sites of pasture, and along roadsides in Oregon and Washington (Lass and Prather 2007).
See Appendix 2C for a breakdown of HS codes and values of each commodity originating from countries where Alopecurus myosuroides is present. No data were available on imports of winter cereal varieties, Appendix 2D for Import data for grass seed and Appendix 2E for Import data for hay and straw.
Based on the world range, Alopecurus myosuroides is likely to survive to NAPPFAST hardiness zone 6 (see figure 2). This would include coastal and extreme southern British Columbia, extreme southwestern Ontario and the coasts of Nova Scotia and Newfoundland. As a weed of winter cereals, the most likely area to be affected would be southwestern Ontario, where winter cereals are grown. The winter wheat growing areas of the southern prairies appear to be outside the species' current range of climatic tolerance.
Probability of Spread
The main means of spread of Alopecurus myosuroides is by human activities. Seeds can be spread in contaminated crop seed, straw or manure. In cereal fields, the seeds of slender foxtail are blown out of the combine with the chaff. Cultivation equipment can also spread seeds. Seeds could easily move in soil during cultivation and in soil attached to farm equipment (CAB International 2007). Wind is the main natural means of dispersal, but seems to function only over relatively short distances (Colbach and Sache 2001).
There are several changes in cultivation practices that have favoured the spread of Alopecurus myosuroides in cereal fields in Europe (Aldrich-Markham 1992; CAB International 2007). Some that would also favour spread in Canada include:
- Suppression of many broadleaf weeds with herbicides has reduced competition for grass weeds such as Alopecurus myosuroides.
- Alopecurus myosuroides responds to high nitrogen fertilization by increasing tiller and seed production.
- Modern harvesting machines favour the dispersal of seeds as most of the seeds are shed by the time of harvest, and the rest are spread over the field with the chaff.
- Increase of autumn sown crops, especially cereals.
- Increased use of reduced tillage systems.
- Banning of straw burning.
- The development of herbicide-resistant populations of the weed.
Potential Economic Consequences
Alopecurus myosuroides is considered one of the most damaging weeds of winter cereals in England (Barkworth 2006) and is also now a major problem in Germany, Belgium and France, as well as parts of Italy, Yugoslavia, and Turkey (Aldrich-Markham 1992). Its spread through Europe has been tied to the expansion of winter wheat and barley acreage, under modern, mechanized cultivation (Aldrich-Markham 1992).
Alopecurus myosuroides occurs in a wide range of crops, but is mainly associated with cereal dominated rotations. It is much commoner in autumn-sown cereal crops, such as winter wheat. It is also found on disturbed land in waste places but does not persist in grassland or pasture (CAB International 2007). It infests other winter crops, including grass seed, rapeseed, and forage legumes (Aldrich-Markham 1992) and is difficult to eradicate from cultivated fields that are repeatedly planted in cereals (Hubbard 1968).
In North America, Alopecurus myosuroides has become a major weed problem in western Oregon and eastern Washington, mostly in cereals, but it has also spread into pastures (Lass and Prather 2007).
Potential Environmental and Social Consequences
Alopecurus myosuroides does not seem to be an environmental weed either in its native or introduced range, being confined to disturbed habitats such as waste places and cultivated fields (Hubbard 1968; Barkworth 2006). There are no obvious potential social consequences to be expected from slender foxtail.
No uncertainties potentially affecting the outcome of the risk assessment were identified.
Based on the outcome of this pest risk assessment, Alopecurus myosuroides is likely to become weedy or invasive in parts of southern Canada (Figure 2). It is recommended that the pest risk analysis process continue for this plant with the completion of a Risk Management Document.
Technical Issues for Consideration
Alopecurus species. The plants are also readily identifiable by trained personnel.
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