Cirsium arvense (creeping thistle)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Biology and Ecology
- Air Temperature
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Threatened Species
- Social Impact
- Risk and Impact Factors
- Uses List
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Cirsium arvense (L.) Scop. (1772)
Preferred Common Name
- creeping thistle
Other Scientific Names
- Cirsium incanum Bieb.
- Cirsium lanatum Spreng.
- Cirsium setosum (Willd.) Bieb.
- Cnicus arvensis Hoffm.
International Common Names
- English: California thistle; Canada thistle; field thistle
- Spanish: cardo
- French: chardon des champs; cirse des champs; sarrette des champs
- Portuguese: cardo-das-vinhas
Local Common Names
- Denmark: ager-tidsel; mark-tidsel
- Finland: pelto-ohdake
- Germany: Ackerdistel; Acker-Kratzdistel; Feldkratzdistel
- Italy: scardaccione; stoppione
- Japan: ezonokitsuneazami
- Netherlands: akkervederdistel
- South Africa: Kanadese dissel
- Sweden: akertistel
- Yugoslavia (Serbia and Montenegro): palamida
- CIRAR (Cirsium arvense)
Summary of InvasivenessTop of page Invasive characteristics include the ability of C. arvense to produce large numbers seeds, (up to 5,300 per plant: Hay, 1937), spread through clonal propagation, and to produce allelopathic effects, all of which promote a wide distribution in agricultural landscapes (Kazinczi et al., 2001; Eber and Brandl, 2003). Crawley et al. (1999) listed C. arvense as among the seven most invasive of weeds in grasslands in the UK. Reproduction by seed chiefly contributes to dispersal, not persistent seed banks (Hill et al. 1989; Heimann and Cussans, 1996; Bond and Turner, 2003). C. arvense thrives in disturbed habitats, and is spread by ploughing and superficial cultivation. Root fragments spread by these means may produce new plants with fragments as small as 3 mm (Drlik et al., 2000; Stolcova, 2002). Larger fragments (21 cm) produced more vigorous shoots than smaller ones (5 cm) (Gustavsson, 1997). Roots readily withstand freezing, thawing and drying, and seeds may remain viable for up to 20 years of storage in the soil (Holm et al., 1991). In North America, C. arvense is on 33 of 38 possible noxious weed lists (Skinner et al., 2000).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Asterales
- Family: Asteraceae
- Genus: Cirsium
- Species: Cirsium arvense
Notes on Taxonomy and NomenclatureTop of page The taxonomy and plant description of C. arvense (L.) Scop. have been reported in several sources (Moore and Frankton, 1974; Moore, 1975; Holm et al., 1977; Donald, 1990), which include keys for the subspecies (varieties) (Moore and Frankton, 1974; Moore, 1975; Donald, 1990). C. arvense has the following varieties or subspecies: vestitum; integrifolium; arvense (syn. mite); horridum (all Wimm. & Grab. 1829). Variability in growth characteristics of different ecotypes has also been reviewed (Donald, 1990).
DescriptionTop of page (After Moore, 1975: pp 1033-1034.)
Perennial herb spreading rapidly by horizontal roots which give rise to aerial shoots. Stems 30-150 cm tall, slender, green, freely branched. Leaves alternate, the base sessile and clasping or shortly decurrent; leaves generally oblong in outline, margin variable from entire to deeply pinnately segmented, spiny. Variation in leaf characters (texture, vestiture, segmentation, spinyness) is the basis for the varieties.
Plants dioecious, all heads of a plant either male or female. Flower heads numerous, 1-5 per branch, 15-25 mm high and 1/3 to 1/4 as wide; male heads globular, somewhat smaller than the flask-shaped female heads. Involucre 10-20 mm high, outer phyllaries ovate, tough-textured, subulate-tipped (0.5 to 0.75-mm stout spine), surface and margins glabrous or lightly arachnoid and with a narrow glandular mid-line; inner phyllaries progressively longer, the innermost unarmed, apex flat, chartaceous, often purplish and erose. Florets all tubular, rose-purple to pinkish, less commonly white. Florets of female heads 23-26 mm long; tube 20-23 mm, lobes about 2 mm; the pistil well-developed but anthers vestigial or absent; florets of male heads 12-14 mm long, tube 7-8.5 mm, lobes 3-4 mm, pistil absent or present and superficially normal but with vestigial ovary; anther 4 mm long, pollen 42-44 µm diameter, tricolporate, exine spiny.
Pappus copious, white, feathery, 20-30 mm long on mature achenes; achenes 2.5-4 x 1 mm, straight or slightly curved, straw or light-brown.
The chromosome number 2n=34 has been reported for all the varieties, in both Europe and Canada.
Plant TypeTop of page Broadleaved
DistributionTop of page The introduction, spread, and distribution of C. arvense have been reviewed, including information gleaned from herbarium samples, perceptual surveys by experts, and scientific surveys in fields (Moore, 1975; Holm et al., 1977; Donald, 1990; Van Acker et al., 2000).
Although the centre of origin of C. arvense is unknown, it probably was originally native to south-eastern Europe and the eastern Mediterranean area (Moore, 1975). However, it has been resident throughout Europe, western Asia, and northern Africa for some time (Moore, 1975; Holm et al., 1977; Holm et al., 1979). More recently C. arvense has spread throughout the temperate zones of South America, Africa, New Zealand, and Australia in the Southern Hemisphere (Holm et al., 1977), and has been found in North America since the 17th century (Moore, 1975). Its historical spread into New Zealand and Australia has been reviewed (Meadly, 1957), as has its distribution in Australia in the 1970s (Amor and Harris, 1974).
The range of C. arvense covers an estimated 9 770 000 km² in North America, extending 2090 km north to south and 4700 km east to west (Moore, 1975). The northern extent of C. arvense is 59°N in Canada and its southern limit is 40°N in the United States (Erickson, 1983). The most severe infestations in the United States occur in the northern half of the country (Hodgson, 1971).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Afghanistan||Restricted distribution||Native||Holm et al., 1979; USDA-ARS, 2004; EPPO, 2014|
|Armenia||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|China||Restricted distribution||Introduced||Holm et al., 1979; Wan et al., 1996; EPPO, 2014|
|Georgia (Republic of)||Present||Native||USDA-ARS, 2004|
|India||Present||Introduced||Holm et al., 1979; Balyan et al., 2000|
|Iran||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Japan||Restricted distribution||Introduced||Holm et al., 1979; EPPO, 2014|
|Korea, DPR||Present||Introduced||Holm et al., 1979|
|Korea, Republic of||Present||Introduced||Holm et al., 1979; Kang et al., 1996|
|Lebanon||Restricted distribution||Holm et al., 1979; EPPO, 2014|
|Pakistan||Present||Introduced||Holm et al., 1979|
|Turkey||Present||Native||Invasive||Holm et al., 1979; Kaya and Zengin, 2000; USDA-ARS, 2004|
|Angola||Present||Introduced||Holm et al., 1979|
|South Africa||Present||Introduced||Moore, 1975; Holm et al., 1979|
|Sudan||Present||Native||Holm et al., 1979|
|Swaziland||Present||Introduced||Holm et al., 1979|
|Tunisia||Present||Native||Holm et al., 1979|
|Zimbabwe||Restricted distribution||EPPO, 2014|
|Canada||Restricted distribution||Introduced||Invasive||Darbyshire, 2003; EPPO, 2014|
|-Alberta||Present||Introduced||Invasive||Moore, 1975; Darbyshire, 2003|
|-British Columbia||Present||Introduced||Invasive||Moore, 1975; Queen's Printer, 2001; Darbyshire, 2003|
|-Manitoba||Present||Introduced||Invasive||Moore, 1975; Darbyshire, 2003|
|-New Brunswick||Present||Introduced||Moore, 1975; Darbyshire, 2003|
|-Newfoundland and Labrador||Present||Introduced||Moore, 1975; Darbyshire, 2003|
|-Northwest Territories||Present||Introduced||Darbyshire, 2003|
|-Nova Scotia||Present||Introduced||Invasive||Moore, 1975; Darbyshire, 2003|
|-Ontario||Present||Introduced||Invasive||Moore, 1975; Cowbrough, 2003; Darbyshire, 2003|
|-Prince Edward Island||Present||Introduced||Moore, 1975; Darbyshire, 2003|
|-Quebec||Present||Introduced||Invasive||Moore, 1975; Darbyshire, 2003|
|-Saskatchewan||Present||Introduced||Invasive||Moore, 1975; Queen's Printer, 1999; Darbyshire, 2003|
|-Yukon Territory||Present||Introduced||Darbyshire, 2003|
|Mexico||Present||Introduced||Holm et al., 1979|
|-California||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Colorado||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Connecticut||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Idaho||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Iowa||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Kentucky||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Maine||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Massachusetts||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Michigan||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Minnesota||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Missouri||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Montana||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Nebraska||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Nevada||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-New Hampshire||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-New Jersey||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-New Mexico||Present||Introduced||Invasive||USDA-NRCS, 2004|
|-New York||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-North Carolina||Present||Introduced||Invasive||USDA-NRCS, 2004|
|-North Dakota||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Ohio||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Oregon||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Pennsylvania||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Rhode Island||Present||Introduced||USDA-NRCS, 2004|
|-South Dakota||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Utah||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Vermont||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Washington||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-West Virginia||Present||Introduced||Hodgson, 1971; USDA-NRCS, 2004|
|-Wisconsin||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|-Wyoming||Present||Introduced||Invasive||Hodgson, 1971; USDA-NRCS, 2004|
|Chile||Restricted distribution||Introduced||Holm et al., 1979; EPPO, 2014|
|Belgium||Restricted distribution||Native||Holm et al., 1979; USDA-ARS, 2004; EPPO, 2014|
|Bulgaria||Widespread||Native||****||Holm et al., 1979; EPPO, 2014|
|Croatia||Present||Native||Stefanic et al., 1999|
|Czech Republic||Widespread||Native||Holm et al., 1979; Burysková, 1997; EPPO, 2014|
|Czechoslovakia (former)||Widespread||Native||****||Holm et al., 1979; USDA-ARS, 2004; EPPO, 2014|
|Denmark||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Estonia||Present||Native||Invasive||Kuill et al., 1999|
|Finland||Restricted distribution||Native||Holm et al., 1979; Jutila, 1996; EPPO, 2014|
|France||Restricted distribution||Native||Holm et al., 1979; Barralis et al., 1996; USDA-ARS, 2004; EPPO, 2014|
|Germany||Present||Native||Invasive||Holm et al., 1979; USDA-ARS, 2004|
|Greece||Present||Native||Holm et al., 1979|
|Hungary||Present||Native||Radványi and József, 2000; USDA-ARS, 2004|
|Iceland||Present||Native||Holm et al., 1979|
|Italy||Present||Native||Holm et al., 1979; Rapparini, 1999; USDA-ARS, 2004|
|Latvia||Present||Native||Invasive||Lapinsh et al., 2000; USDA-ARS, 2004|
|Lithuania||Present||Native||Ciuberkis and Petraitis, 1998; USDA-ARS, 2004|
|Netherlands||Present||Holm et al., 1979|
|Norway||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Poland||Present||Native||Holm et al., 1979; Skrzyczynska, 1999|
|Portugal||Restricted distribution||Native||Holm et al., 1979; USDA-ARS, 2004; EPPO, 2014|
|Romania||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Russian Federation||Present||Native||Holm et al., 1979; Bystraya et al., 2000; USDA-ARS, 2004|
|Slovakia||Present||Native||Holm et al., 1979; Danadová, 2000|
|Slovenia||Present||Native||Holm et al., 1979|
|Spain||Present||Native||Holm et al., 1979; Lete et al., 1997; USDA-ARS, 2004|
|Sweden||Present||Native||Invasive||Holm et al., 1979; Gustavsson, 1994; USDA-ARS, 2004|
|Switzerland||Present||Native||Invasive||Bacher et al., 1997; USDA-ARS, 2004|
|UK||Present||Native||Invasive||Holm et al., 1979; Edwards et al., 2000; USDA-ARS, 2004|
|Ukraine||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Yugoslavia (former)||Present||Native||Holm et al., 1979; USDA-ARS, 2004|
|Yugoslavia (Serbia and Montenegro)||Present||Native||Holm et al., 1979; Stefanovic et al., 1998; USDA-ARS, 2004|
|Australia||Restricted distribution||Introduced||Holm et al., 1979; Australian Weeds Committee, 2004; EPPO, 2014|
|New Zealand||Present||Introduced||Invasive||Holm et al., 1979; Jessep, 1997|
History of Introduction and SpreadTop of page C. arvense was recognized as a troublesome weed in its native region of southeastern Europe by the 16th century, and by the mid-18th century was common throughout Europe (Moore, 1975). C. arvense is thought to have been introduced to North America sometime in the 17th century (Nuzzo, 2000; Moore, 1975). It was brought over from Europe accidentally as a contaminant of farm seed in both New France and New England (Moore, 1975; Whitson et al., 2001). It quickly spread in these spread regions becoming a troublesome agricultural weed. Legislation was enacted as early as 1795 in Vermont and 1831 in New York to control C. arvense (Moore, 1975; Nuzzo, 2000). Presently, C. arvense is widespread throughout the temperate regions of North America between 37° to 59° N (Nuzzo, 2000; Moore, 1975).
Risk of IntroductionTop of page C. arvense has the potential to spread to new areas via contaminated crop seed, irrigation channels, or living organisms. There is very little chance that C. arvense will be spread deliberately as it is widely regarded as a pest in most temperate regions and has no value as an ornamental plant.
HabitatTop of page C. arvense can infest many temperate agricultural crops (Moore, 1975; Donald, 1990; Donald and Nalewaja, 1990; Fay, 1990; Hunter et al., 1990). It is found in both disturbed (tilled) and no-tillage agricultural fields used for producing most annual, winter annual, and perennial agronomic and horticultural crops, as well as adjacent sites, including non-cropped undisturbed roadsides.
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details|
|Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|Riverbanks||Present, no further details|
Hosts/Species AffectedTop of page C. arvense is perennial and often considered 'noxious' (apearing on 33 noxious lists in North America) (Skinner et al., 2000), it has thus been of concern to farmers who grow cereals, oilseeds and forage products. It has been recorded infesting more than 27 crops in 37 countries (Moore, 1975; Holm et al., 1977).
C. arvense can infest many temperate agricultural crops (Moore, 1975; Donald, 1990; Donald and Nalewaja, 1990; Fay, 1990; Hunter et al., 1990). It is found in both disturbed (tilled) and no-tillage agricultural fields used for producing most annual, winter annual, and perennial agronomic and horticultural crops, as well as adjacent sites, including non-cropped undisturbed roadsides, riverbanks, forest edges and open meadows. C. arvense may also be a problem for the propagation of trees (Clay and Dixon, 1997; Siipilehto, 2001).
Host Plants and Other Plants AffectedTop of page
|Aeschynomene falcata (joint vetch)||Fabaceae||Main|
|Allium cepa (onion)||Liliaceae||Other|
|Allium porrum (leek)||Liliaceae||Other|
|Allium sativum (garlic)||Liliaceae||Other|
|Apium graveolens (celery)||Apiaceae||Other|
|Arachis hypogaea (groundnut)||Fabaceae||Other|
|Asparagus officinalis (asparagus)||Liliaceae||Other|
|Avena sativa (oats)||Poaceae||Main|
|Beta vulgaris var. saccharifera (sugarbeet)||Chenopodiaceae||Other|
|Brassica juncea var. juncea (Indian mustard)||Brassicaceae||Other|
|Brassica napus var. napus (rape)||Brassicaceae||Main|
|Brassica nigra (black mustard)||Brassicaceae||Other|
|Brassica oleracea (cabbages, cauliflowers)||Brassicaceae||Other|
|Brassica oleracea var. botrytis (cauliflower)||Brassicaceae||Other|
|Brassica oleracea var. italica (broccoli)||Brassicaceae||Other|
|Brassica oleracea var. viridis (collards)||Brassicaceae||Other|
|Brassica rapa subsp. rapa (turnip)||Brassicaceae||Other|
|Capsicum annuum (bell pepper)||Solanaceae||Other|
|Carthamus tinctorius (safflower)||Asteraceae||Main|
|Chamomilla recutita (common chamomile)||Asteraceae||Other|
|Cicer arietinum (chickpea)||Fabaceae||Other|
|Citrullus lanatus (watermelon)||Cucurbitaceae||Other|
|Cucumis melo (melon)||Cucurbitaceae||Other|
|Cucumis sativus (cucumber)||Cucurbitaceae||Other|
|Cucurbita maxima (giant pumpkin)||Cucurbitaceae||Other|
|Cucurbita pepo (marrow)||Cucurbitaceae||Other|
|Dactylis glomerata (cocksfoot)||Poaceae||Main|
|Daucus carota (carrot)||Apiaceae||Other|
|Fagopyrum esculentum (buckwheat)||Main|
|Fragaria ananassa (strawberry)||Rosaceae||Other|
|Glycine max (soyabean)||Fabaceae||Main|
|Helianthus annuus (sunflower)||Asteraceae||Main|
|Hordeum vulgare (barley)||Poaceae||Main|
|Lactuca sativa (lettuce)||Asteraceae||Other|
|Lagenaria siceraria (bottle gourd)||Cucurbitaceae||Other|
|Linum usitatissimum (flax)||Main|
|Lotus corniculatus (bird's-foot trefoil)||Fabaceae||Main|
|Malus domestica (apple)||Rosaceae||Other|
|Medicago sativa (lucerne)||Fabaceae||Main|
|Nicotiana tabacum (tobacco)||Solanaceae||Other|
|Onobrychis viciifolia (sainfoin)||Fabaceae||Main|
|Panicum miliaceum (millet)||Poaceae||Main|
|Petroselinum crispum (parsley)||Apiaceae||Other|
|Phaseolus lunatus (lima bean)||Fabaceae||Other|
|Piper nigrum (black pepper)||Piperaceae||Other|
|Pisum sativum (pea)||Fabaceae||Main|
|Poa (meadow grass)||Poaceae||Main|
|Prunus avium (sweet cherry)||Rosaceae||Other|
|Prunus domestica (plum)||Rosaceae||Other|
|Pyrus communis (European pear)||Rosaceae||Other|
|Raphanus sativus (radish)||Brassicaceae||Other|
|Rubus fruticosus (blackberry)||Rosaceae||Other|
|Rubus idaeus (raspberry)||Rosaceae||Other|
|Secale cereale (rye)||Poaceae||Main|
|Securigera varia (crown vetch)||Fabaceae||Main|
|Solanum lycopersicum (tomato)||Solanaceae||Other|
|Solanum melongena (aubergine)||Solanaceae||Other|
|Solanum tuberosum (potato)||Solanaceae||Other|
|Sorghum bicolor (sorghum)||Poaceae||Main|
|Spinacia oleracea (spinach)||Chenopodiaceae||Other|
|Triticum aestivum (wheat)||Poaceae||Main|
|Vicia faba (faba bean)||Fabaceae||Other|
|Vigna angularis (adzuki bean)||Fabaceae||Other|
|Vitis vinifera (grapevine)||Vitaceae||Other|
|Zea mays (maize)||Poaceae||Main|
Biology and EcologyTop of page C. arvense is a perennial broadleaved weed with an extensive, spreading perennial root system (Rogers, 1928; Hayden, 1934; Hodgson, 1971; Amor and Harris, 1974; Amor and Harris, 1975; Kigel and Koller, 1985). Adventitious root buds arise from its perennial roots to form new adventitious shoots (Hayden, 1934; Hamdoun, 1970a, 1970b, 1972). This is the major method of vegetative propagation of C. arvense after seedling establishment. Sexual reproduction is by seed (achenes).
C. arvense is adapted to temperate regions, those with moderate summer temperatures and moderate rainfall (450-900 mm/year) (Hodgson, 1968; Holm et al., 1977). The chief factors that limit its spread across continents have not yet been determined unambiguously. However, high summer temperatures may limit its southern spread in North America (Hoefer, 1981).
C. arvense grows on a broad range of soils, including acidic soils with pH levels between 3 and 4 (Dunsford et al., 1998) and soils with a variety of textures. C. arvense produced deeper perennial roots in clay or muck soils (3.8 mm deep) compared to sand, gravel (1 m deep), or limestone (1.8 m deep) soils (Detmers, 1927). Also, C. arvense must have some, as yet unquantified, tolerance to soil salinity, because it was found in 40% of non-marsh, dryland saline sites surveyed in Alberta, Canada (Braidek et al., 1984).
C. arvense seedlings have a juvenile vegetative period before established plants can flower in response to photoperiod (Bakker, 1960), but C. arvense can flower in the same growing season that seedlings emerge. The sexual reproductive system of C. arvense was reviewed by Kay (1985).
Moore (1975) stated that C. arvense was classified by plant taxonomists as dioecious [with male and female flowers on separate plants]. However, Hodgson (1968) observed that male plants of C. arvense occasionally produce achenes (termed 'seed' here), making the species 'imperfectly dioecious'. Lloyd and Mayall (1976) and Delannay (1977, 1979) verified Hodgson's (1968) observations. Seed produced by male plants were smaller and percentage germination was less than for seed formed by female plants.
The viability of C. arvense seed harvested at various times during seed formation and maturation was measured by Gill (1938). Seed germinated 0, 0, and 38% when seedheads were cut when flowering, in flower bud, and when fully mature, respectively (Kinch and Termunde, 1957; Derscheid and Schultz, 1960).
C. arvense seed can be dispersed by transport in contaminated crop seed, feed, packing straw (Cox, 1913; Tonkin and Phillipson, 1973; Holm et al., 1977; Ball et al., 1982), and manure, as well as by irrigation water (Bruns and Rasmussen, 1953, 1957; Moore, 1975) and wind (McKay et al., 1959). Human-assisted dispersal has been more important for the worldwide spread of C. arvense than biological dispersal.
Seed Bank Levels and Seed Persistence
Early field research indicated that C. arvense seed could be quite persistent in soil. For example, some C. arvense seed germinated 22 years after burial 20 cm deep in the field (Madsen, 1962). Seed germinated 45-55% when unearthed after burial 25 cm deep for 5 years in the field (Kjaer, 1948) and 52% after burial 20 cm deep for 3 years (Dorph-Petersen, 1924). Thus, if C. arvense seed were buried > 20 cm deep by moldboard ploughing, a small proportion of seed would persist to re-infest soil if seed were subsequently unearthed by later tillage. However, these early seed persistence studies can be criticized because C. arvense seed were buried well below the depth of normal emergence.
Subsequent research on seed persistence, which simulated more realistic field conditions, showed that C. arvense seed were quite short-lived in the soil. These studies used shallow burial (2.5-7.5 cm deep) and periodic soil disturbance (Roberts and Chancellor, 1979), which are more typical of agricultural fields. Less than 1% of the total number sown remained after 2.5 years in Denmark (Bakker, 1960) and 5 years in England (Roberts and Chancellor, 1979). Most seed were lost from the soil seed bank by germination during the first year after burial at 7.5 cm (48-58%) or 2.5 cm (60%). Soil disturbance is known to speed the rate of loss of other weed seed from the soil seed bank (Roberts, 1964, 1981). When seed persistence of undisturbed seed was assessed in Canada (by emergence alone), no seedlings emerged 3 years after burial (Chepil, 1946). Likewise Hill et al. (1989) reported it was absent from the seed bank among different cropping systems. However, Eber and Brandl (2003) attributed regional persistence of C. arvense partially to the possession of persistent seed banks and Hakansson (2003) warned that C arvense occurring in agricultural headlands may re-infest fields.
Seedling Germination, Emergence, and Phenology in the Field
Almost all C. arvense seed can germinate at maturity and soon after dispersal (Moore, 1975). Fresh mature seed germinated well within 2 to 4 days after being excised from the pericarp (i.e. seed coverings) (Kay, 1985), suggesting that the pericarp restricted germination of freshly shed seed. Environmental effects on germination have been reviewed (Donald, 1994).
Some C. arvense seed can germinate on the soil surface, making the species 'pre-adapted' to reduced or zero tillage (Wilson, 1979). However, no C. arvense seedlings became established from seed spread on the soil surface of a mixed pasture in Australia (Amor and Harris, 1974). When seed were buried 0.5 to 1.0 cm deep, however, 6.8 to 12.6% of seed emerged (Amor and Harris, 1975).
With repeated monthly soil disturbance, C. arvense seedlings emerged from 68% of shallowly buried (2.5 cm deep) seed over 3 years (Roberts and Chancellor, 1979). As planting depth increased, seedling emergence decreased and seedlings from deeper-planted seed emerged later than more shallowly buried seed (Zilke and Derscheid, 1957). In contrast, Derscheid et al. (1956) reported that seed planted deeper than 1.3 cm failed to germinate, while soil type did not greatly influence emergence down to 2 cm (Bakker, 1960). When seed were buried at various depths as low as 6 cm in two sandy loam soils, emergence was greatest from 0.5 to 1.5 cm (Wilson, 1979).
In fields in England, few seedlings emerged in the first autumn after seed were sown in September (Roberts and Chancellor, 1979). Only 3 to 6 months were required for seed to become fully capable of germinating in the field. Winter environments usually prevent C. arvense seed germination. After seed maturation, primary dormancy was short-lived but was followed by longer-term, environmentally enforced (secondary) dormancy. Environmentally enforced dormancy develops if seed experience environmental conditions that prevent germination (Bakker, 1960).
Most seedlings emerged in April and May following burial in the previous autumn, but a small number persisted longer (Bakker, 1960). In Denmark, C. arvense seed were able to germinate 88% in the spring after autumn burial (Dorph-Petersen, 1924). In England, 60% of seed planted 2.5 cm deep and 48-58% of seed planted 7.3 cm deep emerged in the spring after autumn planting (Roberts and Chancellor, 1979).
C. arvense seedlings grow slowly at first and are poor competitors with low shade tolerance (Holm et al., 1977). Shading at 60-70% of full sunlight severely restricted shoot growth, and seedlings died at 80% shade (Bakker, 1960). Plants growing in forests were tall, spindly, and flowered less than plants growing in the open (Detmers, 1927). Clearly, C. arvense grows best under unshaded conditions.
Vegetative Growth of Established Shoots
Emergence phenology of adventitious shoots
Seasonal environment may restrict adventitious root bud elongation of C. arvense, rather than endogenous physiological dormancy (Grondal et al., 2003). In Nebraska (USA), when roots were periodically unearthed, brought indoors, and grown in a high-humidity incubator at 15°C for 2 weeks, there were no seasonal cycles of adventitious root bud activity (McAllister and Haderlie, 1985).
Hodgson (1968) observed that rosettes of C. arvense enlarged for 3 weeks before shoots began to grow vertically. Later-emerging shoots may elongate without rosette formation. Seasonal emergence of adventitious shoots in England (Lawson et al., 1974) and North America (Moore, 1975) has been summarized (Donald, 1994). A study of root longevity in sheep pastures in New Zealand concluded that very little of the overwintering biomass stored in C. arvense (6-10%) persisted into the next growing season (Bourdot et al., 2000).
C. arvense shoots can be propagated from lateral buds at internodes on stem segments (Magnusson et al., 1987) and from adventitious root buds arising on root segments (Moore, 1975). The relative importance of shoots arising from buried vertical stems versus adventitious root buds has not been determined in the field, although it is probably minor.
Adventitious shoot density
C. arvense often forms distinct circular or semicircular patches in fields. C. arvense shoots arising from adventitious root buds often exclude other species in the centre of patches (Bendall, 1975; Stachon and Zimdahl, 1980; Wilson, 1981b).
Typical C. arvense shoot densities in surveys of cereal fields have been summarized (Donald, 1994). Densities declined in the centres of 4- to 5-m-wide patches in Nebraska. In Australia, plant density and height were also reduced near the centre of a 28-m-wide patch from the patch borders, suggesting senescence (Amor and Harris, 1975). Earlier, Pavlychenko (1943) had observed that during a prolonged drought, dense patches of C. arvense became ring-like. Perhaps environmental stress rather than autotoxicity may limit the emergence of C. arvense in well-established patches, especially when patches are stressed by drought.
Under favourable conditions, a C. arvense patch can spread rapidly by vegetative means. One 7.5-cm-long cutting formed a solid patch 7.2 m wide after 3 years of uninterrupted growth (Pavlychenko et al., 1940). Patches spread laterally 0.8-1.6 m per year in Australian pastures, depending upon site and year (Amor and Harris, 1975), 6 m per year in the USA (Hayden, 1934), and 0.8-1.3 m per year in Europe (Bakker, 1960), depending upon site and year. Large patches tend to increase less rapidly than small ones, although established C. arvense clones tend to spread more rapidly (up to 12m per year: Chancellor, 1970) than recently formed clones (Amor and Harris, 1975; Eber and Brandl, 2003). Patches have been observed to degenerate behind an advancing front of C. arvense, likely due to autotoxicity (Amor and Harris, 1975; Bendall, 1975). The allelopathic effect of C. arvense on other plants also aids in formation of dense patches (Stachon and Zimdahl, 1980; Kazinczi et al., 2001) and was found to inhibit other weed species in a cropping situation (Hari et al., 2002).
Crop and land management can reduce the rate of C. arvense patch growth (Donald, 1990). For example, C. arvense did not spread as rapidly in grazed as in ungrazed pastures in Australia (Amor and Harris, 1975).
After shallowly buried seed germinated, seedling roots penetrated 5 to 10 cm before shoots emerged (Bakker, 1960). Horizontal roots developed and adventitious shoots emerged within 6 to 8 weeks after establishment. In Canada, the first lateral roots were initiated at the two-leaf stage when seedings were 4 to 5 weeks old (Friesen, 1968). Adventitious root buds formed on the tap root (Sagar and Rawson, 1964; Friesen, 1968), but the depth of adventitious root bud formation varied. After new C. arvense seedlings became established, their ability to survive clipping by sending up adventitious shoots increased as plants aged (Wilson, 1979).
The depth distribution of C. arvense roots in the soil profile is controversial. In Montana, USA, most roots of 2-year-old plants were found 7.5-30 cm deep (Hodgson, 1968): 54, 30, and 16% of the roots extracted were found in 7.5-22.5, 22.5-37.5, and 37.5-52.5 cm depths, respectively.
Estimates of the maximum depths to which roots extend also vary. Arny (1932) observed that most roots grew no deeper than 40 cm, whereas most horizontal roots were found 20-30 cm deep. Vertical roots grew 1.8-3 m deep in Minnesota, USA (Arny, 1932) and 1.5-1.8 m deep in Iowa (Hayden, 1934). Soil type influenced rooting depth. Maximum depths of 1, 1.8, 3.8, and 4.5 m were observed in sand or gravel, limestone, muck soil, and clay soils, respectively (Detmers, 1927). Maximum depths of 2.4-2.7 m were reported elsewhere (Kiltz, 1930). A 10-year-old undisturbed stand in Canada had roots extending down to 2 m, but most roots were in the top 20 cm (Nadeau and VandenBorn, 1989). Restrictive soil conditions, such as hard pans, gravel or sand layers, alkaline or high calcium soil horizons, and high water tables, may restrict the maximum depth of root penetration (Rogers, 1928). Roots can grow along ped faces in the subsoil (W Donald, University of Missouri, USA, personal communication, 1995).
The maximum depth of emergence of adventitious shoots from adventitious root buds was reported as 0.9 m in Canada (Friesen, 1968).
When left undisturbed, a single C. arvense plant produced 26 emerged adventitious shoots, 154 underground adventitious root buds, and 111 m of roots (> 0.5 mm diameter) after 18 weeks of growth outdoors in boxes (Nadeau and VandenBorn, 1989). Year-to-year variation in root growth was observed (Nadeau and VandenBorn, 1990). Roots sampled down to 1.8 m produced an equivalent number of adventitious shoots compared to shallower sampling depths from a 10-year-old undisturbed stand.
Although the perennial root system of C. arvense probably allows it to survive drought years better than annuals, biomass of perennial roots and numbers of adventitious root buds decrease after several years of drought (Donald, 1992). Drought can suppress subsequent shoot growth for 12 months (Amor and Harris, 1977). The density of C. arvense shoots and adventitious root buds growing in continuous spring wheat decreased in the year following drought years (Donald and Prato, 1992a, 1992b).
Response to Flooding
C. arvense can survive flooding, but this stress resulted in loss of leaves and reduced shoot and root growth (Rogers, 1928; Bakker, 1960; Lenssen et al., 1998).
C. arvense is associated with various animals that create soil disturbances (e.g. rabbits, moles), as well as grazing animals that reduce competing vegetation (Edwards et al., 2000). In northern Germany, an invasion of rats in permanent pastures aided the spread of C. arvense by housing the vegetative portions of the weed in their tunnels (Holm et al., 1991). Pemberton and Irving (1990) found that C. arvense seeds possess elaiosomes, suggesting a possible role for ants in seed dispersal. This mechanism (myrmechochory) may help C. arvense escape predation, avoid competition, or promote germination and establishment in favorable substrates (Pemberton and Irving, 1990). C. arvense populations are also associated with numerous insects, many of which feed on various parts of the plant (Moore, 1975; Eber and Brandl, 2003). Kruess (2003) observed increased insect abundance and diversity was associated with increased abundance of C. arvense on fields in Germany during fallow periods.
C. arvense has been found in almost every plant community in the temperature regions of the world. In a study in Colorado, the following species were associated with dense Canada thistle stands: American bullrush (Scirpus americanus), creeping bentgrass (Agrostis palustris), longstem spikerush (Eleocharis macrostachys), and saltgrass (Distichlis stricta) (Donald, 1994). In moderately dense Canada thistle stands the following species were associated with C. arvense: giant ragweed (Ambrosia trifida), horseweed (Conyza canadensis), common lambsquarters (Chenopodium album), redroot pigweed (Amaranthus retroflexus), prairie sunflower (Helianthus petiolaris), smooth dock (Rumex altissimus), and foxtail barley (Hordeum jubatum) (Donald, 1994). In agricultural fields, C. arvense tends to be associated with other similar and persistent perennial weeds.
C. arvense is an early successional plant, and is typically found in disturbed areas as a part of the initial postdisturbance community. Once established, a single seedling can form a large patch of stems through vegetative propagation of the root system (Moore, 1975). C. arvense is commonly phased out of natural areas once competing plants create a canopy that inhibits the growth and spread of the weed (Hallgren, 1976; Edwards et al., 2000; Vulink et al., 2000; Stolcova, 2002). Rejmanek and Leps (1996) demonstrated that during a six-year period, the competitive relationship between C. arvense and the shrub Arctostaphylos patula shifted as the shrub gained in stature. A five-year study in an agricultural area in Bavaria recorded that 30% of patches became extinct each year, with most of these consisting of small patches subject to human management or intrinsic factors such as lack of suitability of the site for long-term establishment of C. arvense (Eber and Brandl, 2003). In contrast, mountain grazing lands in Poland experienced a marked increase in C. arvense populations four years after grazing had ceased (Kasperczyk and Szewczyk, 1999).
C. arvense is capable of clonal reproduction from buds on horizontal roots (Lalonde and Roitberg, 1994; Whitson et al., 2001). Although clumps of C. arvense may appear uniform, DNA testing has demonstrated that several phenotypes may be present in a single clump (Heimann and Harding, 1996). Sexual reproduction by C. arvense was reviewed by Heimann and Cussans (1996). In terms of reproduction from seed, C. arvense is an obligate outcrosser, thus producing genetically diverse progeny (Lalonde and Roitberg, 1994; Pollak and Bailey, 2001). However, seed set may often be limited by availability of pollen in clonal populations of this normally dioecious plant, which frequently exhibits female-biased offspring sex ratios (Lalonde and Roitberg, 1994). Hermaphrodite flowers are occasionally produced (Heimann and Cussans, 1996). The chromosome number for all C. arvense varieties is 2n=34 (Nuzzo, 2000).
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Absolute minimum temperature (ºC)||-35|
|Mean annual temperature (ºC)||1||20|
|Mean maximum temperature of hottest month (ºC)||22||32|
|Mean minimum temperature of coldest month (ºC)||-14|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Mean annual rainfall||450||900||mm; lower/upper limits|
Soil TolerancesTop of page
Special soil tolerances
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
|Aphis fabae cirsiiacanthoidis||Herbivore|
|Cassida rubiginosa||Herbivore||Leaves/Roots/Stems||Maryland; Virginia|
|Ceutorhynchus litura||Herbivore||Stems||Montana; Saskatchewan; New Zealand|
|Erysiphe mayorii var. mayorii||Pathogen|
|Pseudomonas syringae pv. tagetis||Pathogen|
|Urophora cardui||Herbivore||Stems||New Zealand; Ontario; Saskatchewan|
Notes on Natural EnemiesTop of page Zwolfer (1965) studied the natural enemies of C. arvense in its native range in Europe. Moore (1975) listed arthropods that were observed to feed on C. arvense in North America, where it is an introduced weed. Relatively recently, Perju et al. (1995) collected 61 insect species on C. arvense in Romania, 25 of which were clearly attacking parts of the plant; further work is needed to better characterize this list, but the study indicates potential for the identification of new agents. Wherever C. arvense has been introduced, native organisms have colonized it but do not control it. A biological control programme has been under development in New Zealand for sometime (Cameron et al., 1989; Julien, 1992). By 1997, candidate species were narrowed to four: Lema cyanella, Altica carduorum, Ceutorhynchus litura and Urophora cardui (Jessep, 1997). Similar work has been undertaken in other parts of the world (e.g. North America and China).
There are limitations to the adoption of some of the natural enemies listed as biological control agents against C. arvense. For example, Altica carduorum, a chrysomelid beetle that defoliates and feeds on floral buds in Europe, failed to overwinter in northern USA and Canada (Peschken, 1981; Trumble and Kok, 1982). A population of A. carduorum was recently characterized from a similar climatic region in China, and a phenological model indicated that this strain of A. carduorum had the potential to overlap the range of C. arvense on the Canadian prairies (Lactin et al., 1997). However, its ability to develop on other North American species of Cirsium apparently precludes its use in North America (Wan and Harris, 1997). Cassida rubiginosa defoliated young plants by more than 50%, but did not damage old plants. It is naturalized in eastern Canada, but was slow to establish in Montana (Watson and Keogh, 1980; Peschken, 1981; Forsyth and Watson, 1985; Monnig, 1987), may suffer high winter mortality (Spring and Kok, 1999) and is most damaging at higher temperatures (Bacher and Schwab, 2000).
Ceuthorhynchus litura is a stem-boring weevil that mines leaf veins and root crowns. It may also transmit Puccinia punctiformis, a fungus that causes rust on C. arvense. C. litura was introduced into Canada and the USA from Europe for biological control; however, it has a limited dispersal ability (Peschken and Beecher, 1973; Trumble and Kok, 1982; Rees, 1990). Another European weevil, Cleonis pigra, also feeds at the root crown: feeding leads to gall formation. However, C. pigra does not control C. arvense because the death of infected shoots is limited (Watson and Keogh, 1980; Forsyth and Watson, 1985).
The aphid Brachycaudus cardui, which feeds on floral buds in the USA, is not thought to be a good biological control agent (Detmers, 1927).
Urophora cardui, a European tephritid which forms stem galls, was released in Canada and the USA but only had a slight impact on C. arvense (reduced shoot height) (Watson and Keogh, 1980; Peschken et al., 1982). Another tephritid, Terellia ruficauda, had little effect on established stands in pastures in Canada (Southey and Staniland, 1950; Watson and Keogh, 1980).
A mite, Aceria anthocoptes, specific to C. arvense, was discovered occurring on C. arvense throughout the mid-eastern USA (Ochoa et al., 2001). A. anthocoptes and A. leonthodontis occur in Europe (Petanovic et al., 1997).
Means of Movement and DispersalTop of page Natural dispersal
It is thought that the primary means of long distance travel for C. arvense seeds are dispersal by wind and water, transporting the plumed seeds to new locales (Holm et al., 1991). However, studies have shown that many of the plumes break off and drift away while the seeds remain in the head (Holm et al., 1991).
Viable seeds of C. arvense have been recovered from irrigation water after prolonged submersion (Donald, 1994; Bond and Turner, 2003). After 2 and 22 months of submersion in irrigation water, seeds germinated at a rate of 54 to 92% and 19%, respectively (Donald, 1994). Seeds have also been observed in surface water drainage areas (Drlik et al., 2000).
Seeds can be carried to new locations by sticking to the clothes and shoes of humans, and to the fur and feet of animals (Holm, 1991). Birds that feed on the seeds of C. arvense may carry the plant to new locations. Holmes and Froud-Williams (2001) found that some of the C. arvense seeds ingested by chaffinches were still able to germinate. Rodents that collect and store the vegetative portions of C. arvense have resulted in the appearance of C. arvense in areas that previously did not have the weed (Bond and Turner, 2003). C. arvense may use ants as a means of seed dispersal. Seeds of C. arvense provide a fat- and protein-rich elaiosomes for the ant, and in return the ant carries the seeds away from the parent plants and into or near the ant nest (Pemberton and Irving, 1990). Invasion also occurs via roadways (e.g. Sudbrink et al., 2001).
The movement of C. arvense seeds via agricultural practices is primarily responsible for spreading C. arvense between different regions (Donald, 1994). Seeds of C. arvense have been a contaminant of various crops seeds, resulting in the unintentional spread of the weed to new locations that were previously not effected (Bond and Turner, 2003). As well, the seeds have been found in packing hay and feed for livestock (Holm et al., 1991; Donald, 1994). The animals can then carry the seeds externally or internally, as viable seeds have been found in the manure of heifer and dairy herds (Mt Pleasant and Schlather, 1994).
The spread of C. arvense via vegetative propagation after initial establishment is more important for local spread (Donald, 1994). Common agricultural practices such as ploughing and cultivation distribute fragments of stems and roots allowing the plant to become further spread (Holm et al., 1991; Stolcova, 2002). Root fragments have the ability to survive adversity and regenerate from small pieces. Root fragments as small as 3 - 6 mm are able to produce shoots, and shoot fragments as small as 6 cm were able to produce new shoots (Hayden, 1934). C. arvense also benefits from fields that are left fallow following cultivation or grazing (Kruess, 2001; Kasperczyk and Szewczyk, 1999). Although seeds from C. arvense plants in field margins may result in re-invasion of fields (Hakansson, 2003), the risk appears relatively low (Blumenthal and Jordan, 2001). Another potential source of invasion is the use of agricultural practices that allow survival of large populations of C. arvense, such as in the case in areas with "low levels of agricultural technology" (Reintam and Kuht, 1999).
Movement in Trade
C. arvense seed has been introduced to new locations as an impurity in seed stocks of small grains, as well as in packing straw (Holm et al., 1991).
Pathway VectorsTop of page
Plant TradeTop of page
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Growing medium accompanying plants|
|Stems (above ground)/Shoots/Trunks/Branches|
|True seeds (inc. grain)|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page C. arvense is a major pest and is considered one of the world's worst weeds, ranked as the third most important weed in Europe (Friedli and Bacher, 2001). Yield losses due to C. arvense occur in horticultural crops, field crops, pastures, rangelands, lawns, vineyards and orchards (Hodgson, 1964; 1968; Moore, 1975; Holm et al., 1977; Varadi et al., 1987). It is primarily a weed in perennial forage crops and pastures in North America and Europe and is considered a weed of 27 crops in 37 countries (Holm et al., 1991). C. arvense causes greater crop losses than any other broadleaf weed in its growth range, which includes 10 million km2 in Canada and the northern United States (Drlik et al., 2000). The agricultural crops it affects worldwide include barley, flax, millet, oats, rye, sorghum, wheat and other cereals, rape, canola, corn, beans, peas and other vegetables, vineyards, and orchards (Holm et al., 1991; Van Acker et al., 2000). In the Canadian prairies, a survey of 452 fields (212 wheat, 71 barley, 28 oat, 108 canola, 33 flax) found that C. arvense was the fourth most abundant weed with an average of 1.3 plants/m2. It was fifth most abundant in 1978-1981 and eighth most abundant in 1986 (Van Acker et al., 2000). It has been estimated that C. arvense causes annual losses in Canada of $3.6 million CAD in wheat alone (Peschken et al., 1980b).
C. arvense tends to form relatively isolated patches when it occurs in crops, except in reduced tillage or no-tillage farming systems. The increase in land under reduced tillage systems since the 1980s has lead to increased densities of C. arvense in a variety of cropping systems (Mayor and Maillard, 1995; Mills et al., 1997; Torresen et al., 2003). Although it does not 'take over' entire fields, it may require costly treatment to limit its spread. Donald and Khan (1996) found that among all yield components, the greatest reduction in spring wheat yield due to C. arvense was through early competition that reduced crop density. C. arvense is among the ten most frequently listed noxious weeds in North America (Skinner et al., 2000) and has thus been an important concern to farmers who grow cereals, oilseeds and forage products. Donald (1990) reviewed the economic impact of C. arvense on crop production and the yield loss.
The relative extent to which increasing densities of C. arvense reduce yield has been determined in tilled cropping systems for: winter and spring wheat (45 to 55% maximum yield loss) (Hodgson, 1955; Hodgson, 1968; Peschken et al., 1980b); barley (73% maximum yield loss) (Hodgson, 1955; O'Sullivan et al., 1982); oats (45% maximum yield loss) (Hodgson, 1955); Brassica napus (60% maximum yield loss) (O'Sullivan et al., 1985), alfalfa (Schreiber, 1967) and faba bean (8-12% maximum yield loss) (Kalburtji and Mamolos, 2001). Established natural infestations of C. arvense were used in the above studies (Hodgson, 1968; O'Sullivan et al., 1982, 1985), except for alfalfa (Schreiber, 1967) in which spaced transplants were used.
In pastures, C. arvense reduces forage consumption and cattle will not graze near the plants because of the sharp spines on its leaves (Holm et al., 1991; Drlik et al., 2000). Thus, it restricts the area available for livestock grazing (Donald, 1990; Edwards et al., 2000). A study found that 47% of New Zealand dairy farmers listed C. arvense as being a problem in their pastures (Bourdot et al., 1994). C. arvense can also have a detrimental effect on the health of livestock, as a study found that 16 of 150 weaned calves developed signs of polioencephalomalacia (Loneragan et al., 1998). There were signs of high H2S concentrations found in these calves rumen contents, which was a result of high C. arvense content in hay (Loneragan et al., 1998). C. arvense was recorded as an alternate host of Alfalfa mosaic virus in New Zealand (Fletcher, 2001) and Beet Necrotic Yellow Vein Virus (BNYVV) in Russia (Kutluk et al., 2000).
C. arvense has been investigated for use as an allelopathic agent, against either weeds or soil pathogens (Forleo, 2002; Hari et al., 2002). Extracts were also highly effective against the bacteria Xanthomonas campestris pv. oryzae [X. oryzae pv. oryzae] and Erwinia chrysanthemi pv. zeae (Kaushal-Gautam et al., 2001).
Environmental ImpactTop of page The natural communities where C. arvense has an impact include various non-forested plant communites such as prairies, barrens, savannas, glades, sand dunes, fields and open meadows that have been impacted by disturbance (White et al., 1993; Moore, 1975). It negatively impacts natural environments by crowding out and replacing native grasses and forbs, changing the structure and species composition of natural plant communities and reduces species diversity (White et al., 1993). Although primarily seen as a weed of field and horticultural crops or of natural areas, other environments are also affected such as turf, landscape and nurseries (Gao et al., 1999). As various countries put in place ecological compensation areas or set aside land formerly in agriculture, these lands become vulnerable to invading C. arvense which is often listed as the most common weed in these areas (Davies et al., 1994; Gustavsson, 1994; Barralis et al., 1995; Jewett et al., 1996; Bacher et al., 1997; Bacher and Schwab, 2000; Allen et al., 2001; Nemeth, 2001).
C. arvense produces allelochemicals that are released into the soil that can be toxic to surrounding vegetation, and the phytotoxicity of soil incorporated plant parts can persist for up to 9 weeks (Kazinczi et al., 2001). Kazinczy et al. (2001) found that root and foliage extracts reduced the radicle growth of barley, cucumber, green foxtail and redroot pigweed, and the germination of turnip, soybean, wheat, flax, barley, corn, alfalfa and sunflower. Annual weeds were reduced within stands of C. arvense, although some perennial grasses (Agrostis palustris, Distichlis stricta) and shrubs (Scirpus americanus and Eleocharis macrostachys) persisted (Stachon and Zimdahl, 1980). Species diversity decreased markedly from the periphery to the centre of C. arvense patches (Stachon and Zimdahl, 1980). Water extracts of roots or shoots or soil amended with dried C. arvense roots or shoots reduced the seed germination, establishment, and seedling growth of C. arvense (Donald, 1994).
C. arvense may act as a bioindicator of contamination and used to remediate soil subject to heavy metal pollution, and has been observed to accumulate lead, zinc and chromium (Samkaeva et al., 2001).
Impact: BiodiversityTop of page The impact C. arvense has on natural areas is a relatively new area of study and very little is known on how the plant impacts such ecosystems and the biodiversity. Levine (2000) found in a California study that the most diverse plant communities were the most susceptible to invasive plants, including C. arvense. Negative impacts of C. arvense invasions on biodiversity include crowding out and replacing native grasses and forbs, decreasing the species diversity of an area, and altering ecosystem structure and composition (White et al., 1993). Enhancement of waterfowl populations may require control of C. arvense, to maintain plant community diversity (Krueger-Mangold et al., 2002). C. arvense is seen as a major threat to the Colorado butterfly plant (Gaura neomexicana subsp. coloradensis), listed by the US Fish and Wildlife Service as a threatened species (Munk et al., 2002). In Wyoming, C. arvense infestations have contributed to the elimination of the endangered Colorado butterfly plant (Cheater, 1992). In some contexts, C. arvense may also be beneficial to native organisms. In Washington, C. arvense provided cover for the endangered Columbian white-tailed deer in the summer, allowing deer to utilize previously unused areas (Suring and Vohs, 1979).
Nine hybrids between C. arvense and other Cirsium species were recorded in Europe (Hegi, 1929). Only one of the hybridizing species (C. palustre) has been introduced to North America (Moore, 1975). A possible hybrid between C. arvense and C. hookerianum (a Cirsium species native to North America) was described by Moore and Frankton (1965) as occurring in British Columbia, but did not appear to have significant impacts (Moore, 1975).
C. arvense has invaded several national parks and protected areas. It is one of the most prominent non-native plant species infesting four Great Lakes National Parks (Apostle Islands, Indiana Dunes, Pictured Rocks, and Sleeping Bear Dunes) (Bennett, 2001). In Yellowstone National Park in the USA, C. arvense invaded several burned areas from 1972 to 1988 and now occurs along horse trails, foot trails, and roadways (Turner et al., 1997). A study to determine the frequency of exotic plant species in Yellowstone National Park campgrounds found that C. arvense was the most frequent of the exotic plant species, being found in 6 of 11 campsites (Allen and Hansen, 1999). Following a fire in 1988, several burned sites in Yellowstone National Park have been invaded by C. arvense (Turner et al., 1997). Turner et al. (1997) reported that C. arvense was the most abundant exotic perennial at a burn site near Yellowstone Lake where the plant reached densities of approximately 1100 stems per hectare. The abundance of C. arvense increased with time in all burn severities and the density increased with fire severity (Turner et al., 1997; Crawford et al., 2001). In Mesa Verde National Park in Colorado, C. arvense aggressively invaded bare mineral soils following two major fires occurring in 1989 and 1996 (Floyd et al., 2001). Aerial seeding and herbicide treatments were utilized in an attempt to curtail the invasion of C. arvense, with the latter being the more successful (Floyd et al., 2001). Many exotic plants, including C. arvense, have invaded the National Elk Refuge in Wyoming (Matson, 2000). The primary focus of the refuge was protecting elk, which resulted in overabundance of the ungulates, rendering areas with reduced tree and shrub cover prone to exotic plant invasion (Matson, 2000).
Threatened SpeciesTop of page
|Threatened Species||Conservation Status||Where Threatened||Mechanism||References||Notes|
|Astragalus schmolliae (Schmoll's milkvetch)||CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); NatureServe NatureServe; USA ESA candidate species USA ESA candidate species||Colorado||Ecosystem change / habitat alteration||US Fish and Wildlife Service, 2015a|
|Centrocercus minimus (Gunnison sage-grouse)||USA ESA listing as threatened species USA ESA listing as threatened species||Colorado; Utah||Ecosystem change / habitat alteration||US Fish and Wildlife Service, 2013|
|Cirsium wrightii (Wright's marsh thistle)||NatureServe NatureServe; USA ESA candidate species USA ESA candidate species||Arizona; New Mexico||Competition (unspecified); Ecosystem change / habitat alteration||US Fish and Wildlife Service, 2015b|
|Gaura neomexicana subsp. coloradensis (Colorado butterfly plant)||NatureServe NatureServe; USA ESA listing as threatened species USA ESA listing as threatened species||Colorado; Nebraska; Wyoming||Competition - monopolizing resources||US Fish and Wildlife Service, 2012a|
|Sidalcea nelsoniana||USA ESA listing as threatened species USA ESA listing as threatened species||Oregon; Washington||Competition - monopolizing resources||US Fish and Wildlife Service, 2012b|
|Silene spaldingii (Spalding's catchfly)||USA ESA listing as threatened species USA ESA listing as threatened species||Idaho; Montana; Oregon; Washington||Competition - monopolizing resources; Competition - smothering||US Fish and Wildlife Service, 2007|
Social ImpactTop of page C. arvense affects aesthetic and recreational values in landscape areas and backyards (Donald, 1990; Randall and Marinelli, 1996; Gao et al., 1999). It has been observed along foot trails in national parks, and in the Peace-Athabasca delta (northern Canada) the presence of C. arvense has been reported as an annoyance to hikers (Turner et al., 1997; Wein et al., 1992).
In the past, C. arvense has been used beneficially as a medicinal and edible herb (Rogers, 1928).
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Highly adaptable to different environments
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Highly mobile locally
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Negatively impacts agriculture
- Negatively impacts animal health
- Negatively impacts tourism
- Reduced amenity values
- Reduced native biodiversity
- Competition - monopolizing resources
- Pest and disease transmission
- Produces spines, thorns or burrs
- Highly likely to be transported internationally accidentally
- Difficult/costly to control
Uses ListTop of page
- Miscellaneous materials
- Poisonous to mammals
Prevention and ControlTop of page Introduction
Donald (1990) summarized the management of C. arvense using non-chemical methods and herbicides in various crops. Edwards et al. (2000) provides more recent insights to promote interspecific competition to manage C. arvense through timing of crop sowing, grazing regimes, and nitrogen fertilization. Another useful review proposing integrated strategies for control of C. arvense in crops involving tillage, herbicide use and cultural control is provided by Pollack and Bailey (2001).
C. arvense has been named on most state and federal seed and weed noxious weed laws in the USA. Canadian legislation is similar (Moore, 1975). It appeared on more noxious weeds lists (33) than any other weed in North America (Skinner et al., 2000). C. arvense was introduced into French Canada from Europe (Anon., 1918) before being spread into Vermont and New York in the USA (Stevens, 1846). Detmers (1927) concluded that it must have been introduced before 1795 because a Vermont law was enacted that year to halt its spread. By 1844, Ohio law limited sale of seed contaminated with C. arvense and required landowners to mow infested land and adjacent roadsides (Detmers, 1927). Judging by its current distribution in North America, state and federal legislation has been somewhat ineffective in limiting the spread of the weed (Wilson, 1981a; Skinner et al., 2000). It is also regulated in the UK under the 1959 Weeds Act (Bond and Turner, 2003).
Cultural Control and Sanitary Methods
Combining herbicides with cultivation, mowing or grazing, and competitive crops is more effective for controlling C. arvense than herbicides alone. Various combinations have been tested and reviewed for selective control of C. arvense in the major field crops (Donald, 1990; Edwards et al., 2000). Cultural practices used alone are frequently ineffective. Even when combinations of control practices are used, repeated control measures over several years are required to reduce the severity of the problem (Donald, 1990, 1992, 1994; Donald and Prato, 1992a, 1992b). However, more recent work has identified more specific approaches that may provide effective control. Cover crops show some potential (Moyer et al., 2000). Mowing or grazing needs to be adjusted to levels appropriate for a given system (Wilson and Kachman, 1999; Eerens et al., 2002). Edwards et al. (2000) recommended sowing crops of competing species as soon as possible after cultivation. Populations of C. arvense in field margins were also reduced by sowing other species (West et al., 1997; Denys and Tschamtke, 2002). For example, Ominski et al. (1999) found that Medicago sativa effectively suppressed C. arvense, resulting in more patchy populations. Fertilization, particularly with N may also reduce C. arvense populations, particularly in the absence of grazing (Edwards et al., 2000). Repeated mowing in combination with sowing of perennial grasses has been shown to virtually eliminate C. arvense (Wilson and Kachman, 1999). Cormack (2002) achieved 75% reduction in shoots following mowing in a legume crop. In New Zealand pastures, mowing later in the season resulted in greater reduction in autumnal root biomass (Bourdot et al., 1998). Mitchell et al. (2002) observed that grazing by sheep 3-4 times approximately 3 weeks between grazing depleted root reserves of C. arvense sufficiently to prevent survival. Van Toor and Popay (1995) found that wounding C. arvense plants in advance of grazing increased grazing pressure by sheep by improving palatability. Recent advances in knowledge of the biology of C. arvense, such as the development of shoot emergence models (Donald, 2000; Jensen et al., 2002) should aid in devising management strategies.
Maw (1976) and Moore (1975) summarized information on insects found on shoots and roots of C. arvense. For additional information on insects and nematodes found on C. arvense, see Natural Enemies.
Survey work has identified numerous potential native biological control agents for C. arvense (Watson and Keogh, 1980; Perju et al., 1995). Biological agents for controlling C. arvense have been reviewed (Andres, 1980; Peschken et al., 1980; Trumble and Kok, 1982; Monnig, 1987). Widespread adoption of foreign biological control agents is unlikely because of public concern for native thistles (Peschken and Beecher, 1973) and the general lack of effectiveness of currently available biological control agents. Unfortunately, many of the insects and nematodes listed (see Natural Enemies) are often widespread, persistent pests of important crop species, limiting their use on commercial farms.
The weevil Ceutorhynchus litura severely reduced overwintering survival of below-ground adventitious shoots of C. arvense to as little as 3% of that of uninfested shoots in Canada (Peschken and Beecher, 1973). In a 3-year study in Montana, 8 to 12% of weevil-infested shoots survived from one year to the next compared with 94 to 99% of uninfested shoots (Rees, 1990). This stem feeder was not nearly as devastating in spring as in autumn. Weevil damage also promoted the invasion of damaged shoots by other arthropods (mites, spiders, springtails), nematodes, and fungi, although the role of these organisms in plant death was not determined. The insect may have assisted in spreading the rust fungus, Puccinia punctiformis (Peschken and Beecher, 1973), although this assertion was not substantiated later (Peschken and Wilkinson, 1981). C. litura was released 18 times in the USA in California, Colorado, Idaho, Montana, New Jersey, South Dakota, and Washington between 1971 and 1975. In Montana, C. litura spread 9 km in 10 years and the proportion of infested plants increased from 11 to 29% in 1977 to over 80% after 10 years. In Canada, this insect did not greatly or consistently increase mortality of C. arvense shoots (Peschken and Wilkinson, 1981). A weevil, Larinus planus, that feeds on seed heads of C. arvense was accidently introduced into the USA, and may be useful for controlling seed production to prevent large areas of infestation from expanding (Drlik et al., 2000). However, it has been shown to attack a native thistle, Cirsium undulatum var. tracyi in Colorado (Louda and O'Brien, 2002). Rhiocyllus conicus, a weevil that plays a similar role is no longer favoured for biological control because it also attacks native thistles (Drlik et al., 2000). Predispersal seed predation by Dasyneura gibsoni and Orellia ruficanda can significantly reduce seed output (Forsyth and Watson, 1985; Heimann and Cussans, 1996). Cassida rubiginosa is a fairly effective control agent, and may work well in combination with the effects of competition on C. arvense using plants such as Festuca arundinacea and Coronilla varia (Ang et al., 1995).
Fungi and higher plant parasites found on C. arvense have been reviewed (Moore, 1975; see also Natural Enemies). Most pathogenic viruses or bacteria reported on C. arvense are diseases of crops, such as the tobacco rattle tobravirus (Cooper and Harrison, 1973), limiting their potential for biological control of C. arvense. C. arvense is an alternative host for diseases and nematodes of crops. Drlik et al. (2000) list Pseudomonas syringae pv. tagetis, Puccinia punctiformis, and Sclerotinia scloerotiorum as the three main pathogens under investigation for use against C. arvense in North America. None of these were yet available commercially. Pseudomonas syringae pv. tagetis showed limited ability to affect Canada thistle survival in one USA study (Gronwald et al., 2002), but in Minnesota it reduced C. arvense biomass significantly in conservation tillage systems (Hoeft et al., 2001). Work in Germany has suggested that control with P. punctiformis could prevent flowering and hinder several years' growth (Kluth et al., 2003), and shows some potential for development into a mycoherbicide (Bond and Turner, 2003). The fungus Sclerotinia sclerotiorum applied to C. arvense patches as a biological control agent killed 20 to 80% of shoots in Montana (Brosten and Sands, 1986). Shoot emergence was also severely reduced in the growing season following treatment. Defoliation of shoots has a debilitating effect on the root systems as well (Bourdot and Harvey, 1994). S. sclerotiorum is an aggressive, persistent pathogen on many broadleaved crop species, limiting its use on commercial farms. A study in the Netherlands showed that the risks associated with S. sclerotinium may be manageable, however (Bourdot et al., 2001). Harvey et al. (1998) investigated using auxotrophic strains of S. sclerotinium to decrease the risk of pathogenic effects on crops, but these strains were less effective against C. arvense. Infestation of C. arvense by the bacterium P. syringae tagetis results in stunted plants that are unable to flower and are less able to overwinter (Drlik et al., 2000). Three insects that feed on C. arvense, (Aphis fabae spp. Cirsiiacanthoidis, Uroleucon cirsii and the beetle Cassida rubiginosa) were found to transmit the fungal pathogen P. punctiformis (Kluth et al., 2002), indicating the possibility of using synergism in biological control efforts. Furthermore, Bacher et al. (2002) showed that development of the beetle Apion onopordi was improved in plants infested with P. punctiformis, which is in turn is promoted by A. onopordi (Friedli and Bacher, 2001). However, Kruess (2002) found that the combination of Cassida rubiginosa and the pathogen Phoma destructive provided less efficient control of C. arvense. Green et al. (2001) observed high disease ratings for infection by Alternaria cirsinoxia in Saskatchewan, Canada.
Chemical control of C. arvense has been reviewed (Moore, 1975; Donald, 1990). Different growth stages differ greatly in susceptibility to herbicides. Plants in the rosette stage are more susceptible than plants that have already bolted (Hunter, 1996; Miller and Lym, 1998); seedlings are more susceptible and sensitive to a greater variety of herbicides than mature plants (Vangessel, 1999). With the advent of herbicide-resistant crops, new possibilities for control of C. arvense within crops have appeared, including use of glyphosate, which does provide effective control in these systems (May, 2000; Sarpe et al., 2001).
Herbicides that have been used in different systems:
Bromoxynil, chlorsulfuron, clopyralid, 2,4-D, dicamba, MCPA, metsulfuron, flurasolum, Iodosulfuron-methyl-sodium
Maize and/or sorghum
Atrazine, bentazone, bromoxynil, clopyralid, 2,4-D, dicamba.
Bromoxynil, chlorsulfuron, 2,4-D, dicamba, metsulfuron, picloram, hexazinone.
Atrazine, chlorsulfuron, 2,4-D, dicamba, glyphosate, metsulfuron, picloram.
Amitrole, atrazine, bromoxynil, chlorsulfuron, 2,4-D, dicamba, dichlobenil, glyphosate, hexazinone, imazapyr, metsulfuron, picloram, sulfometuron, tebuthiuron.
ReferencesTop of page
Allen AW, Cade BS, Vandever MW, 2001. Effects of emergency haying on vegetative characteristics within selected conservation reserve program fields in the northern Great Plains. Journal of Soil and Water Conservation (Ankeny), 56(2):120-125; Many ref.
Andres LA, 1980. The biological control of Canada thistle (Cirsium arvense (L.) Scop.) in the United States. Canada Thistle Symposium. Agric. Canada, Regina Research Station, 112-127.
Ang BN, Kok LT, Holtzman GI, Wolf DD, 1995. Canada thistle (Cirsium arvense (L.) Scop.) response to density of Cassida rubiginosa Mnller (Coleoptera: Chrysomelidae) and plant competition. Biological Control, 5(1):31-38; 19 ref.
Anon, 1918. Canada thistle and methods of eradication. USDA Farmers' Bulletin, 1002.
Arnold WE, 1980. Biology and physiology of Canada thistle (Cirsium arvense). Canada Thistle Symposium. Agric. Canada, Regina Research Station.
Arny AC, 1932. Variation in the organic reserves in underground parts of five perennial weeds from late April to November. Minnesota Agricultural Experiment Station Bulletin, 84.
Australian Weeds Committee, 2004. Noxious weed list for Australian states and territories (01/07/2004). National Weeds Strategy: Weeds Australia. World Wide Web page at http://www.weeds.org.au/docs/weednet6.pdf.
Bacher S, Schwab F, 2000. Effect of herbivore density, timing of attack and plant community on performance of creeping thistle Cirsium arvense (L.) Scop. (Asteraceae). Biocontrol Science and Technology, 10(3):343-352; 18 ref.
Bahraini NB, Khajehpour MR, 1999. Chemical control of weeds in winter wheat with postemergence herbicides. Journal of Science and Technology of Agriculture and Natural Resources, 3(3):75-91.
Bakker D, 1960. A comparative life-history study of Cirsium arvense (L.) Scop. and Tussilago farfara L., the most troublesome weeds in the newly reclaimed polders of the former Zuiderzee. Pages 205-222. In: Harper, JL, ed. The Biology of Weeds. Oxford, United Kingdom: Blackwell Scientific Publishers, Ltd.
Ball WS, Mann A, Anderson V, 1982. North Dakota drill box seed survey 1980 and 1981. N. D. State Univ. Coop. Ext. Serv.
Balyan RS, Samunder S, Malik RK, Dhankar RS, Singh S, 2000. Rate and time of application of chlorosulfuron for broadleaf control in wheat. Indian Journal of Weed Science, 32(3-4):173-176.
Barralis G, Dessaint F, Chadoeuf R, 1996. Effects of annual set-aside on subsequent weed invasion in crops. Seizie^grave~me confe^acute~rence du COLUMA. Journe^acute~es internationales sur la lutte contre les mauvaises herbes, Reims, France, 6-8 de^acute~cembre 1995. Tome 2., 703-710; 3 ref.
Bergmann E, Bender J, Weigel HJ, 1999. Ozone threshold doses and exposure-response relationships for the development of ozone injury symptoms in wild plant species. New Phytologist, 144(3):423-435; 44 ref.
Beuerman DSN, Hensley DL, Carpenter PL, 1984. Translocation of glyphosate in Cirsium arvense. HortScience, 19:296-298.
Bond W, Turner RJ, 2003. The biology and non-chemical control of creeping thistle (Cirsium arvense), spear thistle (Cirsium vulgare) and perennial sowthistle (Sonchus arvensis). HDRA Organic Weed Management, Conventry, UK. World Wide Web page at http://www.hdra.org.uk/organicweeds/downloads/thistle_review.pdf.
Bourd(t GW, Harvey IC, 1994. A review of recent research on the microbial control of Californian thistle and other pasture weeds using the fungus Sclerotinia sclerotiorum as a biological herbicide. Proceedings of the New Zealand Grassland Association, 56:43-48; 25 ref.
Bourd(t GW, Leathwick DM, Hurrell GA, 2000. Longevity of Californian thistle roots. New Zealand Plant Protection Volume 53, 2000. Proceedings of a conference, Commodore Hotel, Christchurch, New Zealand, 8-10 August 2000, 258-261; 11 ref.
Bourd(t GW, Leathwick DM, Hurrell GA, Saville DJ, 1998. Relationship between aerial shoot and root biomass in Californian thistle. Proceedings of the Fifty First New Zealand Plant Protection Conference, Quality Hotel, Hamilton, New Zealand, 11-13 August, 1998, 28-32; 9 ref.
Bourdot GW, Hurrell GA, Saville DJ, de Jong MD, 2001. Risk analysis of Sclerotinia sclerotiorum for biological control of Cirsium arvense in pasture: ascospore dispersal. Biocontrol Science and Technology, 11:119-139.
Braidek JT, Fedec P, Jones D, 1984. Field survey of halophytic plants of disturbed sites on the Canadian prairies. Canadian Journal of Plant Science, 64:745-751.
Bruns VF, Rasmussen LF, 1957. The effect of fresh water storage on the germination of certain weed seeds. II. White top, Russian knapweed, Canada thistle, morningglory, and poverty weed. Weeds, 5:20-24.
Bruns VF, Rasmussen LW, 1953. The effect of fresh water storage on the germination of certain weed seeds. I. White top, Russian knapweeds, Canada thistle, morningglory, and poverty weed. Weeds, 2:138-147.
Cameron PJ, Hill RL, Bain J, Thomas WP, 1989. A review of biological control of invertebrate pests and weeds in New Zealand 1874 to 1987. CAB Institute of Biological Control, Technical Communication No. 10. Wallingford, UK: CAB International.
Chancellor RJ, 1970. Biological background to the control of three perennial broad-leaved weeds. Proceedings 10th British Weed Control Conference, 1114-1120.
Cheater M, 1992. Alien invasion. Nature Conservancy, 42(5):24-29.
Cormack WF, 2002. Effect of mowing a legume fertility-building crop on shoot numbers of creeping thistle (Cirsium arvense (L.) Scop.). Proceedings of the UK Organic Research 2002 Conference, Aberystwyth, 225-226.
Cowbrough M, 2003. Noxious weeds (01/09/2003). Ontario Ministry of Agriculture and Food. World Wide Web page at http://www.gov.on.ca/OMAFRA/english/crops/facts/noxious_weeds.htm.
Cox HR, 1913. Controlling Canada thistles. USDA Farmers' Bulletin, 545.
Crawford JA, Wahren C-HA, Kyle S, Moir WH, 2001. Responses of exotic plant species to fires in Pinus ponderosa forests in northern Arizona. Journal of Vegetation Science, 12:261-268.
Darbyshire SJ, 2003. Inventory of Canadian agricultural weeds. Ottawa, Canada: Agriculture and Agri-Food Canada.
Davies DHK, Carnegie HM, 1994. Vegetation patterns and changes in field boundaries and conservation headlands in Scottish arable fields. Field margins: integrating agriculture and conservation. Proceedings of a symposium held at Coventry, UK, 18-20 April 1994 [edited by Boatman, N.] Farnham, UK; British Crop Protection Council (BCPC), 173-178
Delannay X, 1977. Cytological study of dioecy in Cirsium arvense. Phytomorphology, 27(4):419-425
Delannay X, 1979. Evolution of male sterility mechanisms in gynodioecious and dioecious species of Cirsium (Cynareae, Compositae). Plant Systematics and Evolution, 132:327-332.
Derscheid LA, Schultz RE, 1960. Achene development of Canada thistle and perennial sowthistle. Weeds, 8:55-62.
Derscheid LA, Zilke S, Schultz R, 1956. Preliminary studies on pollination and seed germination and maturation of thistles. Proceedings North Central Weed Control Conference, 13:10-11.
Detmers F, 1927. Canada thistle, Cirsium arvense Tourn. Field thistle, creeping thistle. Ohio Agriculture Experiment Station Bulletin, 414.
Dewey HL, 1901. Canada thistle. USDA Bureau Botanical Circular, 27.
Donald WW, 1990. Management and control of Canada thistle (Cirsium arvense). Reviews of Weed Science, 5:193-250.
Donald WW, 1994. The biology of Canada thistle (Cirsium arvense). Reviews of Weed Science, 6:77-101.
Donald WW, Khan, M, 1996. Canada thistle (Cirsium arvense) effects on yield components of spring wheat (Triticum aestivum). Weed Science, 44:114-121.
Donald WW, Nalewaja JD, 1990. Northern Great Plains. Pages 90-126. In: Donald WW, ed. Systems of Weed Management in Wheat in North America. Champaign, IL, USA: Weed Science Society of America.
Donald WW, Prato T, 1992. Effectiveness and economics of repeated sequences of herbicides for Canada thistle (Cirsium arvense) control in reduced-till spring wheat (Triticum aestivum). Canadian Journal of Plant Science, 72(2):599-618
Dorph-Petersen K, 1924. Examinations of the occurrence and vitality of various weed seed species under different conditions, made at the Danish State Seed Testing Station during the years 1896-1923. Report of the 4th International Seed Testing Congress, 124-138.
Eber S, Brandl R, 2003. Regional patch dynamics of Cirsium arvense and possible implications for plant-animal interactions. Journal of Vegetation Science, 14:259-266.
Eerens JPJ, Seefeldt SS, Garry G, Armstrong ML, 2002. Controlling Californian thistle (Cirsium arvense) through pasture management. New Zealand Plant Protection Volume 55, 2002. Proceedings of a conference, Centra Hotel, Rotorua, New Zealand, 13-15 August 2002, 111-115; 7 ref.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Erickson LC, 1983. A review of early introductions of field (Canada) thistle (Cirsium arvense (L.) Scop.) to North America and its present distribution. Proceedings of the Western Society of Weed Science., Vol.36:200-204
Fay PK, 1990. A brief overview of the biology and distribution of weeds of wheat. Pages 33-50. in W. W. Donald, ed. Systems of Weed Management in Wheat in North America. Champaign, IL, USA: Weed Science Society of America.
Fletcher JD, 2001. New hosts of alfalfa mosaic virus, cucumber mosaic virus, potato virus Y, soybean dwarf virus, and tomato spotted wilt virus in New Zealand. New Zealand Journal of Crop and Horticultural Science, 29(3):213-217.
Floyd ML, Hanna DD, Salamach G, 2001. Post-fire treatment of noxious weeds in Mesa Verde National Park, Colorado. Proceedings of the 5th Biennial Conference of Research on the Colorado Plateau, US Geological Survey/FRESC Report Series, 147-157.
Forsberg DE, 1967. Another look at the Canada thistle root system. Proc. Can. Soc. Agron. 8:94-97.
Friedli J, Bacher S, 2001. Direct and indirect effects of a shoot-base boring weevil and plant competition on the performance of creeping thistle, Cirsium arvense. Biological Control, 22(3):219-226; 38 ref.
Friesen HA, 1968. Trends in Canadian research to control Canada thistle. Proceedings Northeastern Weed Control Conference, 22:27-36.
Gao GY, Boggs JF, Bennett PJ, Martin JC, Chatfield JA, Rose MA, Rimelspach JW, Zondag RH, Street JR, Pound WE, 1999. Weed problems in Ohio turf, landscapes, and nurseries: 1998. Special Circular - Ohio Agricultural Research and Development Center, No. 165:55-58; 4 ref.
Gaskin TA, 1958. Weed hosts of Meloidogyne incognita in Indiana. Plant Disease Reporter, 42:802-803.
Gill NT, 1938. The viability of weed seeds at various stages of maturity. Annals of Applied Biology, 25:447-456.
Government of Alberta, Sustainable Resource Development, 2003. Provincial legislation: the weed control act (02/11/2003). Government of Alberta, Sustainable Resource Development, Edmonton, Alberta, Canada. World Wide Web page at http://www3.gov.ab.ca/srd/forests/health/w_legislation.html.
Hamdoun AM, 1970a. The effects of different levels of nitrogen upon Cirsium arvense (L.) Scop. plants grown from seeds and root fragments. Weed Research, 10:121-125.
Hamdoun AM, 1970b. The anatomy of subterranean structures of Cirsium arvense (L.) Scop. Weed Research, 10:284-287.
Harvey IC, Bourd(t GW, Saville DJ, Sands DC, 1998. A comparison of auxotrophic and wild strains of Sclerotinia sclerotiorum used as a mycoherbicide against Californian thistle (Cirsium arvense). Biocontrol Science and Technology, 8(1):73-81; 25 ref.
Hay WD, 1937. Canada thistle seed production and its occurrence in Montana seeds. Seed World, 41:6-7.
Hayden A, 1934. Distribution and reproduction of Canada thistle in Iowa. American Journal of Botany, 21:355-373.
Hegi G, 1929. Illustrierte Flora von Mittel-Europa. VI/2. Munich, Germany: J.F. Lehmanns Verlag.
Heimann B, Cussans GW, 1996. Using RAPD markers to assess genetic variation in an arable weed population of Cirsium arvense L. (Scop.). Xe Colloque International sur la Biologie des Mauvaise Herbes, Dijon, France, 57-63.
Hill NM, Patriquin DG, Kloet SP van der, 1989. Weed seed bank and vegetation at the beginning and end of the first cycle of a 4-course crop rotation with minimal weed control. Journal of Applied Ecology, 26(1):233-246
Hintzshe E, Pallutt B, 1995. Increasing occurrence of creeping thistle. PSP Pflanzenshutz Praxis, 3:23-25.
Hodgson JM, 1955. Canada thistle control with cropping, and with cultural and chemical treatments. Res. Progr. Rep. West. Weed Control Conference, 5-6.
Hodgson JM, 1964. Variations in ecotypes of Canada thistle. Weeds 12, 167-171.
Hodgson JM, 1968. The nature, ecology, and control of Canada thistle. USDA Technical Bulletin, 1386.
Hodgson JM, 1970. The response of Canada thistle ecotypes to 2,4-D, amitrole, and intensive cultivation. Weed Science, 18:253-255.
Hodgson JM, 1971. Canada thistle and its control. USDA Leaflet 52.
Hoefer RH, 1981. Growth and development of Canada thistle. Proceedings North Central Weed Control Conference, 36:153-157.
Holm LG, Plucknett DC, Pancho JV, Herberger JP, 1991. The world’s worst weeds: distribution and biology. Florida, USA: Krieger Publishing Company, USA.
Holmes RJ, Froud-Williams RJ, 2001. The predation and dispersal of weed seeds by birds. The BCPC Conference: Weeds, 2001, Volume 1 and Volume 2. Proceedings of an international conference held at the Brighton Hilton Metropole Hotel, Brighton, UK, 12-15 November 2001, 333-336; 8 ref.
Hope A, 1927. The dissemination of weed seed by irrigation water in Alberta. Sci. Agric., 7:268-276.
Hunter JH, Morrison IN, Rourke DRA, 1990. The Canadian prairie provinces. Pages 51-89. In: Donald WW, ed. Systems of Weed Management in Wheat in North America. Champaign, IL, USA: Weed Science Society of America.
Jewett JG, Sheaffer CC, Moon RD, Martin NP, Barnes DK, Breitbach DD, Jordan NR, 1996. A survey of CRP land in Minnesota: II. Weeds on CRP land. Journal of Production Agriculture, 9(4):535-542; 16 ref.
Kaiser T, 1995. Floristic investigations in an extensive fen pasture with a strongly marked relief. Zeitschrift fur Kulturtechnik und Landentwicklung, 36(3):175-177.
Kang BH, Kwon YW, Lee HK, 1996. Current status and problem of exotic weeds in Korea. Import and export of agricultural products and plant quarantine. '96 International Symposium, Seoul, Korea Republic, 19 May 1996., 101-128; 30 ref.
Kaushal-Gautam, Rao PB, Chauhan SVS, Gautam K, 2001. Antibacterial properties of some weeds of family Asteraceae against Xanthomonas campestris pv. oryzae and Erwinia chrysanthemi pv. zeae. Indian Journal of Weed Science, 33:231-233.
Kigel J, Koller D, 1985. Asexual reproduction of weeds. In Duke SO, ed. Weed Physiology. Vol. 1. Reproduction and Ecophysiology. Boca Raton, FL, USA: CRC Press, 65-100.
Kiltz BF, 1930. Perennial weeds which spread vegetatively. Journal of the American Society of Agronomy, 22:216-234.
Kinch RC, Termunde D, 1957. Germination of perennial sow thistle and Canada thistle at various stages of maturity. Proc. Assoc. Off. Seed Anal., 47:165-166.
Kjaer A, 1948. Germination of buried and dry stored seeds. I. 1934-1939. Proceedings of the International Seed Testing Association, 12:l67-l90.
Kluth S, Kruess A, Tscharntke T, 2003. Influence of mechanical cutting and pathogen application on the performance and nutrient storage of Cirsium arvense. Journal of Applied Ecology, 40(2):334-343; many ref.
Krueger-Mangold J, Sheley RL, Roos BD, 2002. Maintaining plant community diversity in a waterfowl production area by controlling Canada thistle (Cirsium arvense) using glyphosate. Weed Technology, 16(2):457-463; 21 ref.
Kruess A, 2001. Effects of landscape structure on Canada thistle (Cirsium arvense) and its colonization by thistle herbivores and their parasitoids. Mitteilungen der Deutschen Gesellschaft fu^umlaut~r allgemeine und angewandte Entomologie, 13(1-6):29-32; 11 ref.
Kruess A, 2003. Effects of landscape structure and habitat type on a plant-herbivore-parasitoid community. Ecography 26:283-290.
Lactin DJ, Harris P, Johnson DL, Wan F-H, Thomas AG, 1997. Modelling and mapping geographic ranges to evaluate weed biocontrol agents: a case study using Altica carduorum (Coleoptera:Chrysomelidae) and Cirsium arvense (Asteraceae). Biocontrol Science and Technology, 7:657-670.
Lapinsh D, Korolova J, Berzinsh A, 2000. The weediness of spring barley and wheat sowings in the districts of western Latvia. Transactions of the Estonian Agricultural University, Agronomy, No. 209:94-96; 3 ref.
Lawrence GHM, 1955. An Introduction to Plant Taxonomy. New York, USA: The MacMillan Co.
Lawson HM, Waister PD, Stephens RJ, 1974. Patterns of emergence of several important arable weed species. Weed Control in the Northern Environment; Proceedings of a Symposium held 1974, Edinburgh., British Crop Protection Monograph No. 9:121-135
Lete MJ, Aibar J, Zaragoza C, 1997. Weed flora of vineyards of the "Campo de Borja" (Arag=n). Proceedings of the 1997 congress of the Spanish Weed Science Society, Valencia, Spain, 24-26 November 1997., 299-305; 9 ref.
Loneragan GH, Gould DH, Callan RJ, Sigurdson CJ, Hamar DW, 1998. Association of excess sulfur intake and an increase in hydrogen sulfide concentrations in the ruminal gas cap of recently weaned beef calves with polioencephalomalacia. Journal of the American Veterinary Medical Association, 213(11):1599-1604; 39 ref.
Louda SM, O'Brien CW, 2002. Unexpected ecological effects of distributing the exotic weevil, Larinus planus (F.), for the biological control of Canada thistle. Conservation Biology, 16(3):717-727; many ref.
Madsen SB, 1962. Germination of buried and dry stored seeds III, 1934-1960. Proceedings of the International Seed Testing Association, 27:920-928.
Manitoba Agriculture, Food and Rural Initiatives, 2001. Pest management – weeds – declaration of noxious weeds in Manitoba (03/2001). Manitoba Agriculture, Food and Rural Initiatives: Weeds, Insects & Diseases, Regina, Manitoba. World Wide Web page at http://www.gov.mb.ca/agriculture/crops/weeds/fab64s00.html.
May MJ, 2000. Efficiency and selectivity of RR and LL weed control techniques compared to classical weed control systems. 63e Congre^grave~s Institut International de Recherches Betteravie^grave~res, Interlaken, Switzerland, 9-10 fe^grave~vrier 2000., 163-170; 7 ref.
Mayor JP, Mallaird A, 1995. Results from an over-20-years-old ploughless tillage experiment at Changins. IV. Seed bank and weed control. Revue Suisse d’Agriculture, 27:229-236.
McKay HC, Ames G, Hodgson JM, Erickson LC, 1959. Control Canada thistle for greater profits. Idaho Agric. Exp. Bull, 321.
Meadly GRW, 1957. Canada thistle [Cirsium arvense (L.) Scop.]. Journal of Agriculture of Western Australia, 6:697-700.
Mitchell RB, Keoghan JM, Rahman, A, 2002. Pasture and stock management of Californian thistle. Proceedings of the New Zealand Grassland Association Sixty-fourth Conference, West Coast, New Zealand, 64:55-59.
Moore RJ, Frankton C, 1966. Cytotaxonomy of Cirsium hookerianum and related species. Canadian Journal of Botany, 43:597-613.
Munk LM, Hild AL, Whitson TD, 2002. Rosette recruitment of a rare endemic forb (Gaura neomexicana subsp. coloradensis) with canopy removal of associated species. Restoration Ecology, 10(1):122-128; 21 ref.
Nadeau LB, Vanden Born WH, 1989. The root system of Canada thistle. Canadian Journal of Plant Science, 69:1199-1206.
Nadeau LB, Vanden Born WH, 1990. The effects of supplemental nitrogen on shoot production and root bud dormancy of Canada thistle (Cirsium arvense) under field conditions. Weed Science, 38(4-5):379-384
Nova Scotia Department of Agriculture and Fisheries, 2001. Nova Scotia noxious weeds. Nova Scotia Department of Agriculture and Fisheries, Halifax, Nova Scotia. World Wide Web page at http://www.gov.ns.ca/nsaf/elibrary/archive/ipm/weeds.
Nuzzo V, 2000. Element stewardship abstract for Cirsium arvense. The Nature Conservancy, Arlington, Virgina. World Wide Web page at http://www.conserveonline.org/2000/12/b/en/cirsarv.PDF.
Ochoa R, Erbe EF, Wergin WP, Frye C, Lydon J, 2001. The presence of Aceria anthocoptes (Nalepa) (Acari: Eriophyidae) on Cirsium species in the United States. International Journal of Acarology, 27(3):179-187; 42 ref.
Padenov KP, Shcherbakov VA, 2002. Control of the amount of a weed component in agrocoenosis of crops. Vestsi^macron~ Akade^dot over~mi^macron~i^macron~ Agrarnykh Navuk Re^dot over~spubli^macron~ki^macron~ Belarus', No.1:52-54; 6 ref.
Parker C, 1966. Some experience of testing new herbicides on perennial weeds in pots. Proceedings of the 8th British Weed Control Conference, 2:546-552.
Pavlychenko TK, Kirk LE, Kossar W, 1940. Eradication of perennial weeds by the shallow cultivation method. Univ. Sask. Coll. Agric., Agric. Ext. Bull. 100.
Perju T, Teodor LA, Berchez O, Oltean I, 1995. Entomofauna of Cirsium spp. and possibilities of biological control of these weeds with insects. Buletinul Universita^breve~t^tail~ii de S^tail~tiint^tail~e Cluj-Napoca. Seria Agricultura s^tail~i Horticultura^breve~, 49(2):137-143; 10 ref.
Peschken D, Wilkinson F, Finnamore D, 1980. Biological control of Canada thistle in Canada. Canada Thistle Symposium, Agric. Canada Regina Research Station, 140-166.
Peschken DP, 1981. Biological control of Canada thistle. Proceedings North Central Weed Control Conference, 36:169-173.
Peschken DP, Beecher RW, 1973. Ceutorhynchus litura (Coleoptera: Curculionidae): biology and first releases for biological control of the weed Canada thistle (Cirsium arvense) in Ontario, Canada. Canadian Entomologist, 105(12):1489-1494
Peschken DP, Finnamore DB, Watson AK, 1982. Biocontrol of the weed Canada thistle (Cirsium arvense): releases and development of the gall fly Urophora cardui (Diptera: Tephritidae) in Canada. Canadian Entomologist, 114(4):349-357
Peschken DP, Hunter JH, Thomas AG, 1980. Damage in dollars caused by Canada thistle in wheat in Saskatchewan. In: Canada Thistle Symposium. Agric. Canada Regina Research Station, 37-43.
Peschken DP, Wilkinson ATS, 1981. Biocontrol of Canada thistle (Cirsium arvense) : releases and effectiveness of Ceutorhynchus litura (Coleoptera: Curculionidae) in Canada. Canadian Entomologist, 113(9):777-785
Pollak R, Bailey AD, 2001. Grasping the thistle - an integrated strategy for control of Cirsium arvense. The BCPC Conference: Weeds, 2001, Volume 1 and Volume 2. Proceedings of an international conference held at the Brighton Hilton Metropole Hotel, Brighton, UK, 12-15 November 2001, 231-236; 17 ref.
Quebec Ministere de l’Agriculture, des Pecheries et de l’Alimentation, 2002. Fiches descriptives des mauvaises herbes due Quebec (04/24/2002). Quebec Ministere de l’Agriculture, des Pecheries et de l’Alimentation, Centre ARICO. World Wide Web page at http://www.agr.gouv.qc.ca/dgpar/arico/index2.htm.
Queen’s Printer, 1999. The noxious weeds designation regulations being Chapter N-9.1 Reg 2 (effective April 28, 1987) as amended by Saskatchewan Regulations 14/1999. Queen’s Printer, Regina, Saskatchewan, Canada. World Wide Web page at http://www.qp.gov.sk.ca/documents/English/Regulations/Regulations/N9-1R2.pdf.
Queen’s Printer, 2001. Weed control act: weed control regulation [includes amendments up to B.C. Reg. 189/2001]. Queen’s Printer, Victoria, British Columbia, Canada. World Wide Web page at http://www.qp.gov.bc.ca/statreg/reg/W/66_85.htm.
Randall, JM, Marinelli J, 1996. Invasive Plants: Weeds of the Global Garden. Brooklyn, New York, USA: Brooklyn Botanic Garden Publications.
Roberts HA, 1964. Emergence and longevity in cultivated soil of seeds of some annual weeds. Weed Research, 4:296-307.
Rogers CF, 1928. Canada thistle and Russian knapweed and their control. Co. Agric. Exp. Stn. Bull. 348.
Sagar GR, Rawson HM, 1964. The biology of Cirsium arvense (L.) Scop. Proceedings of the 7th British Weed Control Conference, 553-562.
Sarpe J, Mihacea G, 1999. Studies on weed control with different herbicides in maize crops in the conditions of the Danube meadow. Proceedings, 51st International Symposium on Crop Protection, Gent, Belgium, 4 May 1999. Part II. Mededelingen Gaculteit Landbouwkundige en Toegepaste Biologische Wetenschappen, Universiteit Gent, 64(3b):745-753.
Sarpe N, Roibu C, Negrila E, Bodescu F, Fuia S, Popa C, Beraru C, 2001. Chemical control of perennial and annual weeds in herbicide resistant soybean crops. Mededelingen - Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen, Universiteit Gent, 66(2b):743-746; 4 ref.
Schreiber MM, 1967. Effect of density and control of Canada thistle on production and utilization of alfalfa pasture. Weed Science, 15:138-142.
Sheldon JC, Burrows FM, 1973. The dispersal effectiveness of the achene-pappus unit of selected compositae in steady winds with convection. New Phytologist, 72:665-675.
Siipilehto J, 2001. Effect of weed control with fibre mulches and herbicides on the initial development of spruce, birch and aspen seedlings on abandoned farmland. Silva Fennica, 35(4):403-414; 40 ref.
Skrzyczynska J, 1999. Weed infestation of the cultivated fields of Siedlecka Upland against a background of soil conditions: Part I. Weed infestation of grain and root crops. Roczniki Nauk Rolniczych. Seria A, Produkcja Ros^acute~linna, 114(1/2):137-151; 21 ref.
Southey JF, Staniland LN, 1950. Observations and experiments on stem eelworm Ditylenchus dipsaci (Kuhn 1857) Filipjev 1936, with special reference to weed hosts. Journal of Helminthology, 24:145-154.
Stefanic E, Stefanic I, Murdoch AJ, 1999. The influence of different periods of weediness on yield and quality of field beans in Eastern Croatia. 1999 Brighton crop protection conference: weeds. Proceedings of an international conference, Brighton, UK, 15-18 November 1999., Volume 1:331-336; 10 ref.
Stefanovic L, Stanojevic M, Videnovic Z, 1998. Importance of soil tillage in maize perennial weeds control. Comptes-rendus 6e^grave~me symposium Me^acute~diterrane^acute~en EWRS, Montpellier, France, 13-15 Mai, 1998., 341-342.
Stevens A, 1846. Extirpation of Canada thistles. N. Y. Agric. Soc. Trans., 406-428.
Suring LH, Vohs PA, 1979. Habitat use by Columbian white-tailed deer. Journal of Wildlife Management, 43(3):610-619.
Sutton RF, Tinus RW, 1983. Root and Root System Terminology. Forest Science 29 Suppl. Monograph 24. Society of American Foresters.
Thunhorst G, Swearingen JM, 2001. Canada thistle (Cirsium arvense (L.) Scop.). Plant Conservation Alliance, Alien Plant Working Group, Washington, DC. World Wide Web page at http://www.nps.gov/plants/alien/fact/ciar1.htm.
Tonkin JHB, Phillipson A, 1973. The presence of weed seeds in cereal seed drills in England and Wales during spring 1970. J. Natn. Inst. Agric. Bot., 13:1-8.
Toole EH, Brown E, 1946. Final results of the Duval buried seed experiment. Journal of Agricultural Research, 72:201-210.
TOrresen KS, Skuterud R, Tandsµther HJ, Hagemo MB, 2003. Long-term experiments with reduced tillage in spring cereals. I. Effects on weed flora, weed seedbank and grain yield. Crop Protection, 22(1):185-200; 30 ref.
Townsend JL, Davidson TR, 1960. Some weed hosts of Pratylenchus penetrans in Premier strawberry plantations. Canadian Journal of Botany, 38:267-273.
US Fish and Wildlife Service, 2012. In: Gaura neomexicana subsp. coloradensis (Colorado butterfly plant). 5-Year Review: Summary and Evaluation. US Fish and Wildlife Service, 59 pp.. http://ecos.fws.gov/docs/five_year_review/doc4128.pdf
US Fish and Wildlife Service, 2012. In: Nelson's Checker-mallow( Sidalcea nelsoniana). 5-Year Review: Summary and Evaluation. US Fish and Wildlife Service, 44 pp.. http://ecos.fws.gov/docs/five_year_review/doc4004.pdf
US Fish and Wildlife Service, 2013. In: Endangered and Threatened Wildlife and Plants; Endangered Status for Gunnison Sage-Grouse; Proposed Rule. 78(8) US Fish and Wildlife Service, 2486-2538. https://www.gpo.gov/fdsys/pkg/FR-2013-01-11/pdf/2012-31667.pdf
US Fish and Wildlife Service, 2015. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus schmolliae. US Fish and Wildlife Service, 29 pp.. http://ecos.fws.gov/docs/candidate/assessments/2015/r6/Q07C_P01.pdf
US Fish and Wildlife Service, 2015. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Cirsium wrightii. US Fish and Wildlife Service, 37 pp.. http://ecos.fws.gov/docs/candidate/assessments/2015/r2/Q3N3_P01.pdf
USDA-ARS, 2004. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx
USDA-NRCS, 2004. The PLANTS Database, Version 3.5. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov.
van Acker RC, Thomas AG, Leeson JY, Knezevic SZ, Frick BL, 2000. Comparison of weed communities in Manitoba ecoregions and crops. Canadian Journal of Plant Science, 80(4):963-972.
Van Toor RF, 1995. Effect of wounding followed by intensive grazing on Californian thistle control. Proceedings of the forty eighth New Zealand plant protection conference, Angus Inn, Hastings, New Zealand, August 8-10, 1995., 250-251; 5 ref.
Vangessel MJ, 1999. Control of perennial weed species as seedlings with soil-applied herbicides. Weed Technology, 13(2):425-428.
Varadi Gy, Mikulas J, Polos E, 1987. Allelopathy of weeds in vineyards. In Proceedings 1987 British Crop Protection Conference, Weeds Vol 2:671-678.
Vrbanicanin S, Janjic V, 2003. Influence of abiotic factors on the composition of weed vegetation in small grain crops. Proceedings of the 2nd Weed Conference, Sarajevo, Bosnia and Herzogovina, 6-7 June 2003, Herbologia, 4(1):27-37.
Vulink JT, Drost HJ, Jans L, 2000. The influence of different grazing regimes on Phragmites- and shrub vegetation in the well-drained zone of a eutrophic wetland. Applied Vegetation Science, 3(1):73-80; 54 ref.
Wan FangHao, Harris P, Cai LeiMing, Zhang MaoXin, 1996. Biology and ecology of Altica carduorum (Chrysomelidae: Coleoptera) from North-western China: a potential biocontrol agent for Cirsium arvense (Asteraceae) in Canada. Biocontrol Science and Technology, 6(4):509-519; 21 ref.
Wan FH, Harris P, 1997. Use of risk analysis for screening weed biocontrol agents: Altica carduorum Guer. (Coleoptera: Chrysomelidae) from China as a biocontrol agent of Cirsium arvense (L.) Scop. in North America. Biocontrol Science and Technology, 7:299-308.
Watson AK, Keogh WJ, 1980. Mortality of Canada thistle due to Puccinia punctiformis. Proceedings V International Symposium on Biological Control of Weeds, Brisbane, Australia. 325-332.
West TM, Marshall EJP, Arnold GM, 1997. Can sown field boundary strips reduce the ingress of aggressive field margin weeds?. 1997 Brighton crop protection conference: weeds. Proceedings of an international conference, Brighton, UK, 17-20 November 1997., Volume 3:985-990; 4 ref.
White DJ, Haber E, Keddy C, 1993. Invasive Plants of Natural Habitats in Canada: An Integrated Review of Wetland and Upland Species and Legislation Governing their Control. Ottawa, Canada: Canadian Wildlife Service, Environment Canada.
Whitson TD, Burrill LC, Dewey SA, Cudney DW, Nelson BE, Lee RD, Parker R, eds. , 2001. Weeds of the West, edition 9. Newark, CA: Western Society of Weed Science and the Western United States Land Grant Universities Cooperative Extension Services, 92.
Wilson RG Jr, 1979. Germination and seedling development of Canada thistle (Cirsium arvense). Weed Science, 27:146-151.
Wilson RG Jr, 1980. Dissemination of weed seeds by surface irrigation water in western Nebraska. Weed Science, 28:87-92.
Wilson RG Jr, 1981a. Canada thistle - the problem, distribution and economics. Proceedings North Central Weed Control Conference, 36:152-153.
Wilson RG Jr, 1981b. Effect of Canada thistle (Cirsium arvense) residue on growth of some crops. Weed Science, 29:159-164.
Wilson RG, Kachman, SD, 1999. Effect of perennial grasses on Canada thistle, Cirsium arvense, control. Weed Technology, 13:83-87.
Zilke S, Derscheid LA, 1957. Factors affecting germination of Canada thistle and perennial sowthistle seeds. Proceedings North Central Weed Control Conference, 14:42-43.
Ziska LH, 2002. Influence of rising atmospheric CO since 1900 on early growth and photosynthetic response of a noxious invasive weed, Canada thistle (Cirsium arvense). Functional Plant Biology, 29(12):1387-1392; 27 ref.
Zwolfer H, 1965. Preliminary list of phytophagous insects attacking wild Cynarae (Compositae) in Europe. Commonwealth Institute of Biological Control Technical Bulletin, 6:81-154
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