Anthemis cotula (dog fennel)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Biology and Ecology
- Rainfall Regime
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Anthemis cotula L.
Preferred Common Name
- dog fennel
Other Scientific Names
- Anthemis foetida Lam.
- Maruta cotula DC
- Maruta foetida Cassini
International Common Names
- English: mayweed chamomile; stinking chamomile; stinking mayweed
- Spanish: camomilla pudenta; manzanilla hedionda; manzanillon
- French: anthemis fetide; camomille des chiens; camomille maroute; camomille puante; maroute puante
- Portuguese: macela-fetida
Local Common Names
- Germany: Stinkende Hundskamille
- Italy: camomilla cotula; camomilla mezzana
- Japan: kamitsuremodoki
- Netherlands: stinkende kamille
- Sweden: kamomillkulla; surkulla
- ANTCO (Anthemis cotula)
Summary of InvasivenessTop of page
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Asterales
- Family: Asteraceae
- Genus: Anthemis
- Species: Anthemis cotula
Notes on Taxonomy and NomenclatureTop of page
Anthemis is considered to be derived from the Greek word anthemon, 'flower', in reference to its profuse blooming. Cotula is from the Greek word kotule meaning 'a small cup' and referring to a hollow at the base of the amplexicaule leaves.
DescriptionTop of page
A. cotula is very phenotypically plastic, with plants of a wide range of size and habit being observed in any large population within a varied environment, such as a farm field (Kay, 1971). Non-adaptive morphological variation within populations is also common. Example of these variations includes shape and size of ray-florets, morphology of involucral bracts, and the distribution and width of the receptacular bracts. A. cotula is largely self-infertile, which is thought to result in much genetic diversity between and within populations. However, little work has been done on the genetics of Anthemis species to date.
Plant TypeTop of page
DistributionTop of page
A. cotula has been reported to occur from sea-level (Kay, 1971) to altitudes as high as 1640 m (Willkomm and Lange, 1870). Climate and soil type is more important than altitude in determining its occurrence.
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.Last updated: 10 Feb 2022
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Federal Republic of Yugoslavia||Present||Native|
|-Newfoundland and Labrador||Present||Introduced|
|-Prince Edward Island||Present||Introduced|
History of Introduction and SpreadTop of page
There are indications that populations of A. cotula are in decline in Denmark (Erneberg, 1999), Ireland and parts of Scotland, although initial introduction and establishment occurred nearly 500 years ago. It is thought that improvements in seed cleaning technology and herbivory from insects are the reasons for the decline. The environments of these regions are characterized as having moist cool summers with low evapotranspiration demands, and A. cotula populations were perpetuated only by repeated introduction via poorly cleaned seed. Improvements in seed cleaning technology have eliminated this avenue of re-introduction. Recent reports indicate that the species has become rare in Ireland, and in all parts of Scotland, with the exception of a single valley (of the River Tweed) with an environment characterized as having high evapotranspiration demands in summer (Kay, 1971).
In the Pacific Northwest Region of the USA, A. cotula is reported as being more common in arable lands under no-tillage production (Ogg et al., 1993). Soil moisture is generally greater in no-tillage production systems, particularly in spring, and a fair amount of soil disturbance occurs in these systems through fertilizer applications, planting, and other field operations. The result of increased no-tillage production in this region is an increase in the number of fields infested with A. cotula, greater areas of infestations in fields where it is present, and greater population densities in infested areas (Gealy et al., 1994).
HabitatTop of page
The climatic range of A. cotula is limited by a combination of decreasing summer temperature and increasing rainfall (Kay, 1971). It is most abundant in areas with relatively warm summers (mean temperature of 15°C or greater) with rainfall less than 880 mm. In the Pacific Northwest region of the USA, it is known to infest arable lands in areas with annual rainfall as low as 450 mm. A. cotula has difficulty sustaining populations in areas with greater than 880 mm annual rainfall, but has been reported to be locally common in areas with greater than 10,000 mm rainfall with high summer evapotranspiration. Evapotranspiration rates, particularly during summer, appear to define the climatic range of A. cotula.
Soil type and fertility appears to be the most important factor in predicting where A. cotula occurs within its climatic range. It occurs most frequently on fertile clay and clay-loam soils (Clapham et al., 1962). Ellenberg (1950) describes favourable soil conditions as rather wet, weakly acidic to alkaline with high nitrogen content. It may also occur on medium-textured soils, particularly if sites are poorly drained, but is usually rare or absent on light soils (Kay, 1971).
A. cotula is commonly found along roadsides and in poorly managed pastures in the USA (Smith, 1987), and is becoming increasingly problematic as a weed in cropping systems in the Pacific Northwest Region of the USA (Gealy et al., 1994). In this region, mayweed infestations were previously restricted to low, wet areas, but recently the species has become increasingly established in other areas as well. This may be due to conservation tillage practices in which soil moisture remains high for extended periods of time and weed seeds remain at or near the soil surface (Gealy et al., 1985).
Habitat ListTop of page
|Terrestrial||Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Protected agriculture (e.g. glasshouse production)||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Rail / roadsides||Present, no further details|
|Terrestrial||Managed||Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Natural forests||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Riverbanks||Present, no further details|
|Terrestrial||Natural / Semi-natural||Wetlands||Present, no further details||Harmful (pest or invasive)|
|Littoral||Coastal areas||Present, no further details||Harmful (pest or invasive)|
Hosts/Species AffectedTop of page
Although A. cotula is not thought to grow in undisturbed sites, it is been noted as a problem in legume or mixed grass/legume pastures, particularly during establishment (Smith, 1987). Damage due to A. cotula in pastures include toxic properties (Kingsbury, 1964) or poor palatability influencing forage preference by animals, and potential allelopathic influence on interseeded species (Smith, 1987).
A. cotula has been found to have allelopathic effects (Smith, 1987, 1990). Results of laboratory bioassays and growth chamber experiments indicated that water extracts of A. cotula are potentially allelopathic to alfalfa (Medicago sativa) and Italian ryegrass (Lolium multiflorum) seedlings. A. cotula leaf tissue mixed in potting soil significantly reduced the growth of these species. The extract and tissue concentrations used in this research were estimated to be similar to concentrations expected to occur within pastures (Smith, 1987). Leaf tissue extracts had a stronger effect than did those from stems and roots, and the effect was more pronounced for seedling growth than for germination (Smith, 1990).
Recently, A. cotula has been described as a problem in native plant communities, particularly during re-establishment of desired vegetation. As with pastures, the main concern in native environments is reduced forage quality and potential allelopathic influences.
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page
Biology and EcologyTop of page
Chromosome number of A. cotula has consistently been reported as n = 9 (Mulligan, 1957; Kay, 1971).
Hybrids between A. cotula and A. tinctoria, A. arvensis, Tripleurospermum inodorum [T. maritimum], and Matricaria recutita (Rohlena, 1930) have been recorded, but reports lack details of achene morphology, pollen fertility, chromosome number, and meiotic behavior necessary to confirm hybridization (Kay, 1971). Experimental reciprocal crosses without emasculation yielded a single hybrid between A. cotula and A. arvensis and many hybrids between A. cotula and T. inodorum, but no hybrids between A. cotula and M. recutita. Apparent A. cotula x T. inodorum hybrids have been found in large mixed populations in the field on two occasions in England (Kay, 1971).
Physiology and Phenology
A. cotula achene germination will occur all year, but peak germination occurs in spring or autumn. Internode elongation on flowering stems begins in May. Flower bloom begins in mid-June and may continue through November with peak bloom occurring in mid-July. Spring-emerging plants begin flowering in July and continue through August. Often, a second peak of flowering will occur in September and October following cereal grain harvest (Kay, 1971).
In a study of factors influencing germination of A. cotula seeds, Gealy et al. (1985) found that maximum percentage germination for seeds and achenes occurred at 20°C, and that achene germination was lower than seed germination under all conditions tested. Both acid scarification for 15 minutes and soaking in a 14 mM gibberellic acid solution more than doubled achene germination. Pericarp leachate inhibited achene and seed germination at high concentrations, indicating that pericarp leachate is not the primary cause of reduced achene germination. Optimum germination occurred at a pH of 4.5, while the range was from pH 3 to pH 6. Achene germination was inhibited by moisture stress to a greater degree than was seed germination. A soil moisture potential of -10,000 kPa reduced germination and total plant weight by as much as 95% and 80%, respectively (Gealy et al., 1994).
Ray flowers of A. cotula are normally male, but are sometimes infertile female florets. Disc florets are complete, but self-pollination is less than 10%, so the species is considered strongly self-incompatible. However, self-compatibility has been observed in isolated plants in specialized habitats (Kay, 1971).
Pollination is largely via insect vectors, with several Syrphidae and Tachinidae species observed visiting flowers. Insect visits to flowers decline during periods of poor weather and later in the season. Scarcity of insect pollinators may account for poor seed set following periods of poor weather and in the late season (Kay, 1971).
Each capitulum produces many achenes which are circular in cross-section and contain a single smooth seed. The outer surface of the pericarp wall, which encloses the seed, has ten roughened longitudinal ribs. Achenes are 1.3 to 1.8 mm long and 0.7 to 1.9 mm wide (Gealy et al., 1985).
Achene production per plant varies widely. The number of capitula per plant ranges from one to a few hundred depending on the environment. The number of fertile flowers per capitulum varies with environmental conditions, the season, and the position of the capitulum on the plant. Large capitula have been observed to produce up to 120 seeds, but average achene number per capitulum is 50-75. However, achene production per plant varies greatly with environment and was reported to range from 550 to 1,375, 2,800 to 4,200, and 7,500 to 12,000 for average-sized plants at three locations in the UK. The largest plants in that survey had approximately 27,000 achenes (Kay, 1971).
A varying proportion of A. cotula achenes is infertile as a result of failure of fertilization or abortion of the embryo. The proportion of infertile achenes is commonly 10 to 25% and may range to 50% or greater under unfavourable conditions (Kay, 1971).
Germination and emergence are normally very low in the autumn of the year in which the achenes are produced, much higher the following year, and slightly higher in the third year (Roberts and Neilsen, 1981).
Achenes of A. cotula buried in damp sand remained viable for 25 years but not for 30 years at Lansing, Michigan, USA (Darlington, 1931). Salzmann (1954) obtained 63% germination after 1 year of burial, 68% after 3 years, and 6% after 11 years.
Alternating temperatures strongly promote achene germination (Cerna, 1957). Most effective temperature regimes under laboratory conditions were 16 h at 20 or 30°C alternating with 8 h at 0°C, which resulted in 100% germination over 20 d. Constant temperatures of 20 and 30°C resulted in 16 and 13% germination, respectively, over 60 d. Ilnicki and Johnson (1959) found combinations of light and alternating temperatures between 20 and 30°C gave the greatest germination, although total germination was low.
A. cotula may have detrimental effects on neighbouring plants both via competition and allelopathic effects. Competition experiments showed that A. cotula is a weak competitor against peas (Pisum sativum), but because it continues to grow after peas senesce it interferes with crop harvest, and dense stands reduce pea growth (Ogg et al., 1993). Greenhouse experiments showed that the interference between A. cotula and peas occurs mainly underground, and that soil moisture is more important than nitrogen in controlling the outcome of this interaction. Decreasing soil moisture increased the aggressiveness of A. cotula relative to pea. Nitrogen added at 20 mg per week had no effect on peas, but more than doubled the size of A. cotula, though the aggressivness of the latter was not increased (Ogg et al., 1994).
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Mean annual rainfall||0||0||mm; lower/upper limits|
Rainfall RegimeTop of page
Soil TolerancesTop of page
- seasonally waterlogged
- very acid
Natural enemiesTop of page
Notes on Natural EnemiesTop of page
Botrytis cinerea may damage A. cotula plants quite severely, especially in a wet climate or environment (Kay, 1971).
Means of Movement and DispersalTop of page
Movement of A. cotula may occur via water, but non-biotic natural dispersal is not a significant problem.
Vector Transmission (Biotic)
A. cotula achenes do not have structures that allow for easy biotic transmission. Achenes may occur in mud or soil caked onto animal hooves or hide, in the cuffs of trousers, or in animal faeces (Kay, 1971). However, these are not common means of dispersal.
A. cotula achenes are most commonly spread by agricultural practices. Early infestations in cereal grains were thought to be largely via contaminated seed. Populations decreased with even the earliest improvements in seed cleaning methods and equipment (Kay, 1971).
Achenes may also move from field to field via contaminated tillage and harvest equipment. Introductions have also been documented through the movement of hay, bedding, manure, and animals containing achenes in their stomachs that are later excreted (Kay, 1971).
Initial introductions via ship ballast have been reported. A. cotula may also have been confused with Matricaria recutita, or spread as a seed contaminant of this species or other related plants.
A. cotula has been introduced for potential medicinal or other human uses in limited areas, mainly eastern Asia and South America.
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Growing medium accompanying plants||weeds/seeds|
|True seeds (inc. grain)||weeds/seeds|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Stems (above ground)/Shoots/Trunks/Branches|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page
Environmental ImpactTop of page
Impact: BiodiversityTop of page
Risk and Impact FactorsTop of page
- 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
- Negatively impacts agriculture
- Negatively impacts human health
- Negatively impacts animal health
- Reduced native biodiversity
- Competition - monopolizing resources
- Highly likely to be transported internationally accidentally
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
- Difficult/costly to control
UsesTop of page
Uses ListTop of page
- Poisonous to mammals
Similarities to Other Species/ConditionsTop of page
A. cotula is also often confused with Chamaemelum nobile, Matricaria perforata [Tripleurospermum maritimum], Matricaria recutita, and Matricaria discoidea [Matricaria matricarioides]. However, its offensive odour, finely dissected leaves, and fine-haired stems below the capitula distinguish A. cotula.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.Cultural Control
Cultural control of A. cotula is achieved by methods including improved drainage, crop rotation, using competitive varieties, and delayed spring planting. Improved seed cleaning techniques have lessened the abundance of A. cotula, particularly in cereal grain rotations (Kay, 1971).
As an annual weed, A. cotula is easily controlled by tillage, particularly in early growth stages. Mechanical control may be applied preplant, pre-emergence, or in-row for effective control. Hand-weeding is also quite effective, but can be extremely laborious with heavy infestations, and the plant may cause irritation.
Sulfonylurea herbicides effectively control A. cotula. However, biotypes have been identified that are resistant to this group of herbicides. Clopyralid, picloram, and triclopyr provide good control of A. cotula, particularly when applied with growth-regulating herbicides such as dicamba, 2,4-D, or MCPA. Control is only fair with applications of dicamba, 2,4-D, or MCPA alone. Control is fair to good with metribuzin and diuron.
Control of A. cotula in forage crops using herbicides was investigated by Smith (1987). Glyphosate and paraquat applied during mid-March after germination of A. cotula and before initiation of growth by forage species provided good weed control with minimal crop damage.
Although certain insects and pathogens are known to attack A. cotula, no biological control programmes have been developed.
Problems caused by A. cotula in crop production are limited to cereal rotations. Crop rotations utilizing varying planting dates and herbicide are effective for control. In pastures and forage production, improving plant competition via interseeding or fertilizer application can be effective in control. Eliminating seed introduction via contaminated seed, hay, bedding, or manure is most effective in preventing new or re-infestations of A. cotula.
ReferencesTop of page
Cerna J, 1957. The biology of weeds of the family compositae. Thesis. Charles University, Prague, Czechoslovakia.
Clapham AR; Tutin TG; Warburg EF, 1962. Flora of the British Isles. Second edition. Cambridge, UK: Cambridge University Press.
Ellenberg H, 1950. Landwirtschaftliche Pflanzensoziologie. Stuttgart, Germany: Ulmer.
Hitchcock CL; Cronquist A, 1973. Flora of the Pacific Northwest. Seattle, USA: University of Washington Press.
Holm L; Pancho JV; Herberger JP; Plucknett DL, 1979. A Geographical Atlas of World Weeds. Toronto, Canada: John Wiley and Sons Inc.
Ilnicki RD; Johnson MW, 1959. Temperature, light, and seed size and their effects on germination of dog fennel. Proceedings of the 13th NE Weed Control Conference. 13:440.
Kay QON, 1971. Biological flora of the British Isles. Anthemis cotula L. Journal of Ecology, 59:623-636.
Kingsbury JM, 1964. Poisonous plants of the United States and Canada. Englewood Cliffs, New Jersey, USA: Prentice-Hall Inc.
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Ogg AG Jr; Stephens RH; Gealy DR, 1994. Interference between mayweed chamomile (Anthemis cotula) and pea (Pisum sativum) is affected by form of interference and soil water regime. Weed Science, 42(4):579-585
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Smith AE, 1987. Increasing importance and control of mayweed chamomile in forage crops. Agronomy Journal, 79:657-660.
Smith AE, 1990. Potential allelopathic influence of certain pasture weeds. Crop Protection, 9:410-414.
Stokoe WJ; Stovin GHT, 1948. The Caterpillars of British Moths including the Eggs, chrysalids and Food-plants. Series II. Warne, Wayside & Woodland series, UK: Warne.
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