Cuscuta epithymum (alfalfa dodder)
- 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
- Growth Stages
- Biology and Ecology
- Latitude/Altitude Ranges
- Air Temperature
- Rainfall Regime
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Plant Trade
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Social Impact
- 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
- Cuscuta epithymum (L.) L. 1774
Preferred Common Name
- alfalfa dodder
Other Scientific Names
- Cuscuta alba C. Presl
- Cuscuta barbuvea Samp.
- Cuscuta epithymum subsp. trifolii (Bab.) Hegi
- Cuscuta prodanii Buia
- Cuscuta stenoloba Bornm. & O. Schwarz
- Cuscuta trifolii Bab. (1843)
International Common Names
- English: clover dodder; common dodder
- Spanish: cuscuta del trebol; epitimo
- French: cuscute du thym; cuscute du thyme; cuscute du trefle
- Portuguese: cabelos
Local Common Names
- Belgium: klaverwarkruid
- Denmark: klover-silke
- Finland: apilanvieras
- Germany: Klee- Seide; Ouendel-Seide; Thymian-Seide
- Italy: cuscuta del trifoglio; cuscuta piccola
- Netherlands: duivelsnaaigaren; klein Warkruid
- New Zealand: devil's gut
- South Africa: klein dodder; lesser dodder
- Sweden: kloeversnaerja
- CVCEY (Cuscuta epithymum)
Summary of InvasivenessTop of page
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Solanales
- Family: Cuscutaceae
- Genus: Cuscuta
- Species: Cuscuta epithymum
Notes on Taxonomy and NomenclatureTop of page
Two subspecies are generally recognized in C. epithymum, ssp epithymum (= ssp. trifolii) and ssp. kotschyi (e.g. Valentine, 1972). Feinbrun (1970) also recognizes the varieties epithymum, angustissima and alba within ssp. epithymum. Yuncker (1932) distinguishes the varieties macranthera, angustissima, alba, rubella, kotschyi, sagittanthera and scabrella.
DescriptionTop of page
Plant TypeTop of page
Vine / climber
DistributionTop of page
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 Jan 2020
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Federal Republic of Yugoslavia||Present||Native|
|Hungary||Present, Few occurrences||Native|
|Russia||Present||Present based on regional distribution.|
|United States||Present||Present based on regional distribution.|
|Australia||Present||Present based on regional distribution.|
|-New South Wales||Present||Introduced|
|New Zealand||Present, Widespread||Introduced|
History of Introduction and SpreadTop of page
Risk of IntroductionTop of page
Dry heat at 100°C for 15 minutes has been shown to selectively kill seeds of Cuscuta spp. in nigerseed (Guizotia abyssinica) (Strasser, 1988), providing a means of de-contaminating contaminated imports, but it is not certain that this is being used in practice.
HabitatTop of page
Habitat ListTop of page
|Terrestrial||Managed||Cultivated / agricultural land||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||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|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
Host Plants and Other Plants AffectedTop of page
|Achillea millefolium (yarrow)||Asteraceae||Wild host|
|Asperula cynanchica (squinancywort)||Rubiaceae||Wild host|
|Calluna vulgaris (heather)||Ericaceae||Wild host|
|Daucus carota (carrot)||Apiaceae||Main|
|Hormathophylla spinosa||Brassicaceae||Wild host|
|Lotus corniculatus (bird's-foot trefoil)||Fabaceae||Wild host|
|Medicago sativa (lucerne)||Fabaceae||Main|
|Pteridium esculentum||Dennstaedtiaceae||Wild host|
|Thymus praecox||Lamiaceae||Wild host|
|Trifolium pratense (red clover)||Fabaceae||Main|
|Ulex europaeus (gorse)||Fabaceae||Wild host|
|Ziziphus lotus (wild jujube)||Rhamnaceae||Wild host|
Growth StagesTop of page
Biology and EcologyTop of page
Chromosome number 2n = 14
Physiology and Phenology
Cuscuta species are obligate parasites with negligible chlorophyll, totally dependent on attachment to a host plant within a few days after germination. Germination does not depend on the presence of host plants, but occurs over a prolonged period, as there is a proportion of hard-coated seeds which gradually become permeable and allow absorption of water. This ensures that not too many seeds germinate at one time in the possible absence of a potential host plant. In many species, there is also an innate dormancy which is broken by chilling over the winter. Seed germination is very high in C. epithymum, the optimal temperature being 15-20°C. On germination, a very short root is formed which provides anchorage only, while the plumule elongates rapidly and, in the light, circumnutates widely anticlockwise until contact is made with a stem or other solid object. The length of the seedling rarely exceeds 10 cm and if a host is not located, the seedling dies within a few days. Once contact with a stem or other object is made, the shoot will twine around it, whether living or inanimate and the root and shoot base below this point will soon die. The coiling action requires blue or far-red light and is suppressed under red light or darkness. If a suitable host stem is found, several coils will develop, with pre-haustorial swellings on the inner face of the coiled stem, from which full haustoria develop in the presence of cytokinins, which derive partly from the parasite and partly from the host. Intrusive organs develop from the haustorium and searching hyphae penetrate the host tissues by a combination of separation and penetration of cells (these processes, for Cuscuta species generally, are reviewed by Parker and Riches, 1993). Connections are then formed by a bridge of tracheids with the host xylem; whereas connection with the phloem via plasmodesmata between searching hyphae and host parenchyma cells has also been confirmed by Dorr (1987). Once the haustorial connection is complete, new shoot buds develop close by. Some Cuscuta species, notably C. reflexa, have measurable levels of chlorophyll and photosynthesis, but C. epithymum does not.
Vegetative growth may continue for some time before any flowers are formed, or flowering may occur very rapidly. Flowering is thought by some authors to be linked to the flowering of the host plant but this is not apparently consistent. Although normally annual in behaviour, C. epithymum stems may survive over winter on the crowns of red clover (Trifolium pratense) and lucerne or on weeds (Stojanovic and Mijatovic, 1973).
Cuscuta species are propagated mainly by seed, though individual plants may spread vegetatively over many separate host plants. Stem fragments may also be able to establish new plants, though it is not known whether this can occur with C. epithymum. Cross-pollination by insects is believed to occur, as to be expected from the notable fragrance of the flowers which can be quite striking from a sizeable population, but C. epithymum may be self-pollinated when insects are not present (Gaertner, 1950). Seed production from a single plant can reach 16,000 (Holm et al., 1997).
There are no specialized dispersal methods for Cuscuta species and without the assistance of man or animals, it is presumed to depend on soil or water movement (Dawson et al., 1994).
C. epithymum behaves mainly as an annual species but haustorial tissue may perennate within the crowns of legumes or weeds (Ashton and Santana, 1976).
The mainly temperate distribution of C. epithymum suggests that this species is dependent on a cool or cold winter period for 'stratification' and breakage of seed dormancy. There is no evidence of association with particular soil types, or level of soil fertility, nor any requirement for especially moist or dry conditions.
On limestone pavement in Ireland, C. epithymum was found in Asperulo-Seslerietum vegetation, an association assigned to the chalk grassland class Festuco-Brometea. The vegetation of the limestone pavement habitat was compared with mature dune grassland at Fanore, also in the Burren region of Ireland, where extensive populations of C. epithymum occur in vegetation assigned to the Camptothecio-Asperuletum, another association belonging to the Festuco-Brometea class (Doyle, 1993).
Latitude/Altitude RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Mean annual temperature (ºC)||12||20|
|Mean maximum temperature of hottest month (ºC)||30|
|Mean minimum temperature of coldest month (ºC)||-14|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Dry season duration||0||7||number of consecutive months with <40 mm rainfall|
|Mean annual rainfall||155||1100||mm; lower/upper limits|
Rainfall RegimeTop of page
Soil TolerancesTop of page
Special soil tolerances
Natural enemiesTop of page
Notes on Natural EnemiesTop of page
Horvath (1983) notes that S. jungermanniae is widespread in Hungary where it has 2-3 generations a year and is oligotrophic on dodders, including Cuscuta campestris and C. epithymum ssp. epithymum (C. trifolii). It has been used in the USSR for the biological control of Cuscuta spp. It prevents flowering and fruiting on about 30-40% of the parasite plants.
Means of Movement and DispersalTop of page
Natural, non-biotic, dispersal of Cuscuta seed is very limited and must occur mainly by water.
Vector Transmission (Biotic)
Animals may help spread of Cuscuta on an occasional basis following ingestion, or by transfer of soil containing the seeds.
Man is by far the most important dispersal agent, thanks to the harvesting and transport of crop material contaminated with vines and seeds of Cuscuta, and by movement of soil on farm machinery.
Accidental introduction across national boundaries can quite readily occur when Cuscuta seed is a contaminant of crop seed, as it may well be in seed of clovers or lucerne.
Intentional introduction is relatively unlikely, though any Cuscuta species could occasionally be regarded as a botanical curiosity and introduced for this reason.
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|
|Fruits (inc. pods)||seeds|
|Growing medium accompanying plants||seeds|
|Stems (above ground)/Shoots/Trunks/Branches||stems|
|True seeds (inc. grain)||seeds|
|Plant parts not known to carry the pest in trade/transport|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page
Holm et al. (1979) record C. epithymum as a 'serious' weed in Afghanistan, Hungary, Poland and Turkey, a 'principal' weed in Italy, Portugal and the former USSR, and 'common' in Canada, Iran, South Africa, Spain and Venezuela. The crops affected are presumed to be mainly clovers, lucerne and carrot. In Holm et al. (1997) C. epithymum is described as being a weed of 25 crops in 13 countries.
Infestations of C. epithymum on Hormathophylla spinosa (Cruciferae) in Spain did not significantly affect the fruit or seed production of its host plant, either during the study years or the years following strong infestation (Gomez, 1994) but in this case the dodder caused little harm mainly because it was scarce.
Environmental ImpactTop of page
Impact: BiodiversityTop of page
Social ImpactTop of page
Risk and Impact FactorsTop of page
- Invasive in its native range
- Proved invasive outside its native range
- Highly adaptable to different environments
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Negatively impacts agriculture
- Competition - monopolizing resources
- Highly likely to be transported internationally accidentally
- Difficult/costly to control
UsesTop of page
Uses ListTop of page
Similarities to Other Species/ConditionsTop of page
Severova (1991) describes a range of characters useful for distinguishing different Cuscuta spp., including C. epithymum. The most comprehensive key is provided by Yuncker (1932). Keys to the European species are provided in Flora Europaea (Valentine, 1972) and by Feinbrun (1970) while Parker and Riches (1993) include most of those of agricultural significance.
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
Use of clean crop seed is vital. Seed crops which might have been infested should be inspected and cleaned if necessary, or seed should be obtained from a source known to be reliable. Separation of Cuscuta seeds from lucerne is quite successfully achieved by equipment comprising felt- or velvet-covered rollers to which the rough seeds of Cuscuta stick while the smoother crop seeds pass over (see Dawson et al., 1994).
Rotation with non-susceptible crops can be helpful. Cereals are virtually immune, but some broad-leaved crops may also be sufficiently resistant, including soyabean, kidney bean (Phaseolus vulgaris), squash (Cucurbita sp.), cucumber and cotton (see Parker and Riches, 1993).
Deep shade suppresses the coiling and attachment of Cuscuta; hence, encouraging a dense crop canopy is a valuable component of any integrated control programme.
The young seedlings of Cuscuta, with rudimentary roots, are readily destroyed by shallow tillage before or after crop establishment. Hand-pulling is suitable only for scattered infestations as the infested crop plants have to be removed with the parasite. Scattered infestations of C. campestris have also been controlled by heat, using a hand-held flame gun. More extensive infestations of that species in lucerne are also sometimes treated with overall flaming, as the crop is able to recover. Close mowing is an alternative means of control in lucerne and clovers.
There is relatively little information on the use of herbicides against C. epithymum but propyzamide has been used for its control in lucerne in the former Czechoslovakia (Froliseck, 1986) and chlorpropham for its control on Calluna vulgaris (Belgium, 1962).
Other herbicides of value in the control of other Cuscuta species, especially C. campestris, include metham-sodium and dazomet as pre-planting fumigants, trifluralin and related compounds, chlorthal-dimethyl, chlorpropham, pendimethalin, fluchloralin, butralin, etc. in lucerne and some other legumes. These might be expected to be equally effective against C. epithymum.
Biological control of C. epithymum has been considered in Yugoslavia, by augmentative release of the gall-forming weevil Smicronyx jungermanniae, but results were not encouraging (Parker and Riches, 1993). Attempts at biological control of other Cuscuta species have involved other Smicronyx species and the fly Melanagromyza cuscutae but with generally uncertain results according to Julien and Griffiths (1998). Among pathogens, a selected strain of Colletotrichum destructivum was shown to affect C. epithymum selectively in lucerne (Parker and Riches, 1993), and Alternaria cuscutacidae and a form of Colletotrichum gloeosporioides [Glomerella cingulata] have given helpful results against C. chinensis and C. australis (Parker and Riches, 1993; Julien and Griffiths, 1998).
The prospects for biological control of C. epithymum and other Cuscuta spp. have been reviewed by Girling et al. (1979).
Integrated methods for control of Cuscuta species generally involve the all-important use of clean seed; good field hygiene to eradicate scattered infestations before they get out of control; good control of other weeds which might act as reservoirs of infestation; timing of tillage and planting to maximize destruction of parasite seedlings before sowing; and optimum planting arrangement and growing conditions for a good crop canopy to suppress development of the weed.
ReferencesTop of page
Ashton FM; Santana D, 1976. Cuscuta spp. (dodder): a literature review of its biology and control. University of California, Division of Agricultural Sciences Bulletin 1880.
Belgium, 1962. [Survey of the practical results obtained in 1962.] (in Flemish) Publication of the Rijkslandbouhogeschool, Centrum Onkruiddonderz., Gent. 11 pp.
Cagán L; Komáromyová E; Barta M; Tóth P, 2001. Cuscuta lupuliformis Krocker (Cuscutaceae) - a new host for bean aphid, Aphis fabae Scopoli (Homoptera, Aphididae). Acta Fytotechnica et Zootechnica, 4(3):84.
Dawson JH; Mussleman LJ; Wolswinkel P; Dorr I, 1994. Biology and control of Cuscuta. Reviews of Weed Science, 6:265-317.
Doyle GJ, 1993. Cuscuta epithymum (L.) L. (Convolvulaceae), its hosts and associated vegetation in a limestone pavement habitat in the Burren Lowlands in County Clare (H9), western Ireland. Biology and Environment. Proceedings of the Royal Irish Academy, Section B, 93B:61-67
Feinbrun N, 1970. A taxonomic review of European Cuscutae. Israel Journal of Botany, 19:16-29.
Gaertner EE, 1950. Studies of seed germination, seed identification and host relationships in dodders, Cuscuta spp. Cornell Agricultural Experiment Station Memoirs 294. 56 pp.
Holm LG; Doll J; Holm E; Pancho JV; Herberger JP, 1997. World Weeds: Natural Histories and Distribution. New York, USA: John Wiley & Sons Inc.
Julien MH; Griffiths MW, 1998. Biological control of weeds: a world catalogue of agents and their target weeds. Biological control of weeds: a world catalogue of agents and their target weeds., Ed. 4:x + 223 pp.
Marwat KB; Marwat GR; Sarim FM, 1993. A checklist and key to parasitic weeds of Pakistan. Pakistan Journal of Weed Science Research, 6(1-2):1-15.
Parasitic Plant Connection, 2003. http://www.science.siu.edu/parasitic-plants/index.html.
Severova E, 1991. New taxonomic characters in the genus Cuscuta (Cuscutaceae). Proceedings of the 5th international symposium of parasitic weeds, Nairobi, Kenya, 24-30 June 1991 [edited by Ransom, J.K.; Musselman, L.J.; Worsham, A.D.] Nairobi, Kenya; CIMMYT (International Maize and Wheat Improvement Center), 514-518
Stefanovic S; Krueger L; Olmstead RG, 2002. Monophily of the Convolvulaceae and circumscription of their major lineages based on DNA sequences of multiple chloroplast loci. American Journal of Botany, 89:1510-1522.
Stojanovic D; Mijatovic K, 1973. Distribution, biology and control of Cuscuta spp. in Yugoslavia. Symposium on Parasitic Weeds, Malta, 1973, 269-279.
USDA, 2003. USDA, ARS, Germplasm Resources Information Network Online Database at: http://www.ars-grin.gov/cgi-bin/npgs/html.
Valentine DH, ed. , 1972. CXLVI Convolvulaceae. In: Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA, eds. Flora Europaea Volume 3. Diapensiaceae to Myoporaceae. Cambridge, UK: Cambridge University Press, 74-83.
Veljkovic B; Vrbnicanin S; Bozic D; Radanovic Z, 2007. Cuscuta campestris (Ynck) and Cuscuta epithymum (Murr.): serious problems in alfalfa in Serbia. In: European Weed Research Society, 14th EWRS Symposium, Hamar, Norway, 17-21 June 2007 [ed. by Fløistad, E.]. Doorwerth, Netherlands: European Weed Research Society, 74. http://www.ewrs-symposium2007.com
Webb CJ; Sykes WR; Garnock-Jones PJ, 1988. Flora of New Zealand Volume IV. Naturalised Pteridophytes, Gymnosperms and Dicotyledons. Christchurch, New Zealand: DSIR Botany Division, 1365 pp. http://floraseries.landcareresearch.co.nz/pages/Book.aspx?fileName=Flora%204.xml
Wolswinkel P, 1979. Transport of assimilates and mineral elements at the site of attachment of Cuscuta. The role of phloem unloading in the parasitic relationship. Proceedings, Second International Symposium on Parasitic Weeds, North Carolina, 1979., 156-164
Wolswinkel P; Ammerlaan A, 1983. Sucrose and hexose release by excised stem segments of Vicia faba L. The sucrose-specific stimulating influence of Cuscuta on sugar release and the activity of acid invertase. Journal of Experimental Botany, 34(148):1516-1527
Yuncker TG, 1932. The genus Cuscuta. Memoirs of the Torrey Botanical Club, 18:113-331.
CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Cagáň L, Komáromyová E, Barta M, Tóth P, 2001. Cuscuta lupuliformis Krocker (Cuscutaceae) - a new host for bean aphid, Aphis fabae Scopoli (Homoptera, Aphididae). Acta Fytotechnica et Zootechnica. 4 (3), 84.
USDA, 2003. USDA, ARS, Germplasm Resources Information Network Online Database., http://www.ars-grin.gov/cgi-bin/npgs/html
Valentine DH, 1972. CXLVI Convolvulaceae. In: Flora Europaea Volume 3. Diapensiaceae to Myoporaceae, [ed. by Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA]. Cambridge, UK: Cambridge University Press. 74-83.
Veljkovic B, Vrbnicanin S, Bozic D, Radanovic Z, 2007. Cuscuta campestris (Ynck) and Cuscuta epithymum (Murr.): serious problems in alfalfa in Serbia. In: European Weed Research Society, 14th EWRS Symposium, Hamar, Norway, 17-21 June 2007 [European Weed Research Society, 14th EWRS Symposium, Hamar, Norway, 17-21 June 2007.], [ed. by Fløistad E]. Doorwerth, Netherlands: European Weed Research Society. 74. http://www.ewrs-symposium2007.com
Webb CJ, Sykes WR, Garnock-Jones PJ, 1988. Flora of New Zealand. Naturalised Pteridophytes, Gymnosperms and Dicotyledons., IV Christchurch, New Zealand: DSIR Botany Division. 1365 pp. http://floraseries.landcareresearch.co.nz/pages/Book.aspx?fileName=Flora%204.xml
Distribution MapsTop of page
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