Datasheet

Enhanced

13 September 2024

Cuscuta europaea (European dodder)

Author: Miguel GarcíaAuthors Info & Affiliations

Publication: CABI Compendium

17113

https://doi.org/10.1079/cabicompendium.17113

Datasheet Types: Pest, Natural Enemy, Invasive Species

PDF/EPUB

Abstract

This datasheet on Cuscuta europaea covers Impact, Identity, Overview, Associated Diseases, Pests or Pathogens, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control and Further Information.

Identity

Preferred Scientific Name: Cuscuta europaea L.
Preferred Common Name: European dodder
Other Scientific Names: Cuscuta brachystyla K. Koch; Cuscuta epicnidea Bernh.; Cuscuta europaea f. someseana Buia; Cuscuta europaea f. valachica Buia; Cuscuta europaea subsp. indica Engelm.; Cuscuta europaea subsp. nefrens (Fr.) O. Schwarz; Cuscuta europaea var. conocarpa Engelm.; Cuscuta europaea var. epilobii F. Aresch.; Cuscuta europaea var. epilotum F. Aresch.; Cuscuta europaea var. halophyta (Fr.) Hartm.; Cuscuta europaea var. indica Engelm.; Cuscuta europaea var. nefrens Fr.; Cuscuta europaea var. nepalensis Yunck.; Cuscuta europaea var. podolica Tacik; Cuscuta europaea var. schkuhriana (Pfeiff.) Nyman; Cuscuta europaea var. segetum (Rota) Nyman; Cuscuta europaea var. vacua Gren.; Cuscuta europaea var. viciae Engelm.; Cuscuta halophyta Fr.; Cuscuta halophyta var. ligustri (F. Aresch.) Nyman; Cuscuta laxiflora Aznav., non Benth.; Cuscuta ligustri F. Aresch.; Cuscuta major DC.; Cuscuta major var. ambigens Rouy; Cuscuta major var. nefrens (Fr.) Celak.; Cuscuta major var. vacua (Gren.) Rouy; Cuscuta major var. viciae (Engelm.) Rouy; Cuscuta sarothamni Brügg.; Cuscuta schkuhriana Pfeiff.; Cuscuta segetum Rota; Cuscuta solani Holuby; Cuscuta tubulosa J. Presl & C. Presl
International Common Names: English
greater dodder; French
cuscute d'Europe
Local Common Names: China
ou zhou to si zi; Czech Republic
kokotice evropska; Germany
Europäische Seide; Italy
cuscuta; Japan
kushironenashikazura; Netherlands
groot warkruid; Spain
cabellos de venus; Sweden
naesselsnaerja
EPPO code: CVCEU (Cuscuta europaea)

Pictures

Growing plant of Cuscuta europaea (European dodder) on Tanacetum vulgare. Utterslev Mose, Copenhagen, Denmark. July 2015. — Habit
Cuscuta europaea (European dodder); Growing on Tanacetum vulgare. Utterslev Mose, Copenhagen, Denmark. July 2015.
©Donald Hobern/via Flickr - CC BY 2.0

Growing plant of Cuscuta europaea (European dodder) on Urtica dioica. Spain. September 2014. — Habit
Cuscuta europaea (European dodder); Growing on Urtica dioica. Spain. September 2014.
©Joan Simon/via Flickr - CC BY-SA 2.0

Growing plant of Cuscuta europaea (European dodder) on Urtica dioica. Baierhansenwiesen, Dreieich, Germany. July 2022. — Inflorescence
Cuscuta europaea (European dodder); Growing on Urtica dioica. Baierhansenwiesen, Dreieich, Germany. July 2022.
©Robert Flogaus-Faust/via Wikimedia Commons - CC BY-SA 4.0

Inflorescence of Cuscuta europaea (European dodder). East of Altenmarkt im Thale, Lower Austria. November 2018. — Inflorescence
Cuscuta europaea (European dodder); Inflorescence. East of Altenmarkt im Thale, Lower Austria. November 2018.
©Stefan Lefnaer/via Wikimedia Commons - CC BY-SA 4.0

Flowers of Cuscuta europaea (European dodder). Visp, Wallis, Switzerland. July 2008. — Flowers
Cuscuta europaea (European dodder); Flowers. Visp, Wallis, Switzerland. July 2008.
©Hans Hillewaert/via Wikimedia Commons - CC BY-SA 3.0

Flowers of Cuscuta europaea (European dodder). Harmannstein, Lower Austria. August 2017. — Flowers
Cuscuta europaea (European dodder); Flowers. Harmannstein, Lower Austria. August 2017.
©Stefan Lefnaer/via Wikimedia Commons - CC BY-SA 4.0

Flower of Cuscuta europaea (European dodder). Harmannstein, Lower Austria. August 2017. — Flower
Cuscuta europaea (European dodder); Flower. Harmannstein, Lower Austria. August 2017.
©Stefan Lefnaer/via Wikimedia Commons - CC BY-SA 4.0

Seeds of Cuscuta europaea (European dodder). Harmannstein, Lower Austria. August 2017. — Seeds
Cuscuta europaea (European dodder); Seeds. Harmannstein, Lower Austria. August 2017.
©Stefan Lefnaer/via Wikimedia Commons - CC BY-SA 4.0

Seeds of Cuscuta europaea (European dodder). Ukraine. November 2017. — Seeds
Cuscuta europaea (European dodder); Seeds. Ukraine. November 2017.
©Yuliya Krasylenko/via Wikimedia Commons - CC BY-SA 4.0

Diseases Table

Summary of Invasiveness

Cuscuta europaea is an annual parasitic plant that connects with its host through stem haustoria. It is profusely branched covering the host with its thread-like twining stems and spreading to nearby plants. Its original range of distribution is Asia and Europe with very localized populations in N Algeria and Libya. It was introduced to Maine and New York at the end of the 19th century but was not naturalized. It is not listed as a threatened species in any part of its native range.

Cuscuta europaea has not proved to be a highly invasive species and does not naturalize outside its native distribution range. Compared to other species of the genus there is not a significant risk of accidental introduction because it normally grows on native plants, not crops. Nevertheless, it is frequently listed as quarantine pest together with other species of the genus.

Taxonomic Tree

Notes on Taxonomy and Nomenclature

Cuscuta europaea was described by Linnaeus (1753) including two varieties, var. europaea and var. epithymum L., the latter combined to the species rank in 1759 (García and Cafferty, 2005). Yuncker (1932) lists many synonyms, recognizing two varieties previously described by Engelmann (1859), var. indica Engelm. and var. conocarpa Engelm. Feinbrun (1972) concludes that although the species shows some variation, mostly on fruit shape, development of infrastaminal scales and apex of calyx and corolla lobes, it is not sufficiently consistent to allow delineation of subspecies or varieties. Yuncker (1957) described var. nepalensis Yunck. from Jumla, Nepal, characterized by the stout styles and stigmas shorter than the ovary but otherwise not different from the type of variety.

Cuscuta europaea belongs to subgenus Cuscuta, one of the four subgenera accepted by Costea et al. (2015), characterized by having two styles and elongated stigmas. García and Martín (2007) resolved all the accessions of C. europaea sister to a clade including the SW Asian C. balansae Boiss. & Reut. and C. approximata Bab.

Morphologically similar, C. kurdica Engelm. might be confused with individuals of C. europaea with few flowered glomerules. Cuscuta kurdica has acute calyx and corolla lobes and flowers are smaller (Plitmann, 1978). Although most characters overlap, García and Martín (2007) did not resolve one clear accession of C. kurdica in the clade of C. europaea and might be different species.

Common names: European dodder, greater dodder.

Plant Type

Annual

Seed / spore propagated

Vegetatively propagated

Herbaceous

Parasitic

Vine / climber

Description

Annual parasitic herb with stems up to 1.6 mm in diameter, reddish to whitish, few to much branched. Inflorescence in dense glomerules, up to 22 mm in diameter, with (2-)5-20 flowers. Flowers tetramerous o pentamerous, up to 4 mm long sessile or more frequently on a subcylindric or obconic pedicel. Calyx campanulate, generally as long as the corolla tube but also shorter or longer; calyx lobes 1.1-2.2 x 0.8-1.8 mm, ovate or ovate-elliptic, generally with blunt apex or rarely acute, with entire margin, free or somewhat imbricate at the base; calyx tube 0.3-1.1 mm, shorter than the lobes. Corolla tubular in anthesis to urceolate in fruit, smooth, whitish; corolla lobes 0.8-1.4 x 0.8-1.5 mm, ovate, blunt or subacute, free or slightly imbricate at the base, erect or erect-spreading; corolla tube 0.7-1.7 mm, shorter to longer than the tube. Infrastaminal scales 0.5-1.3 x 0.3-1.1 mm, obovate or oblong-truncate, frequently bifid or toothed, shorter than the corolla tube, thin and adpressed to the tube. Stamens 0.4-1.0 mm, shorter than the corolla lobes; anthers 0.3-0.5 x 0.3-0.5 mm, ovoid, oblong o subglobose, yellowish or reddish, frequently with thickened connective at the apex; filaments 0.1-0.5 mm, terete or subconic, shorter to longer than the anthers. Styles 0.2-0.4 mm, terete or somewhat flattened; stigmas 0.2-0.8 mm, terete, reddish or yellowish, generally longer than the styles; stigmas and styles together shorter or as long as the ovary. Fruit 1.4-3.0 x 2.0-3.1 mm, a subglobose or pyriform and regularly dehiscent at the base capsule, with the apex frequently thickened and sometimes covering the styles, with 2-4 ovoid or subglobose seeds, 0.9-1.5 x 0.7-1.2 mm, sometimes joined in pairs.

Detailed descriptions are available in Feinbrun (1972) for Europe, Costea and Nesom (2024) for N America and Rhui-cheng et al. (1995) for China. General description in Yuncker (1932). Fritsche et al. (1958) provide detailed descriptions of the anatomy and morphology of C. europaea.

Seeds are similar to other species of Cuscuta subgen. cuscuta as described by Olszewski et al. (2020). The stem tip grows with a convoluted movement in search of a host. When it makes contact with a compatible host, it develops the first haustorium in which the hifae-like cells of Cuscuta contact the xylem and phloem of the host. Once the haustorium completes its development, the Cuscuta stem grows and branches very quickly producing new haustoria and eventually covering nearby hosts. A David Attenborough's video of the establishment of C. europaea on Urtica showing the different stages from seedling to flowering is available in https://www.youtube.com/watch?v=e54UKuGEP1E.

During the stages from seedling to vegetative growth, it is impossible to distinguish the species simply with morphological features. Flowering is frequently in synchrony with the host or once it starts producing fruits. C. europaea produces globose and compact inflorescences with one bract at the base. It is differentiated from closely related species by the thick obconic pedicel frequently about as long as the calyx, free or scarcely overlapping ovate to elliptic calyx lobes and truncate or bifid corolla scales, thin and adpressed to the tube.

The type variety of C. europaea was lectotypified by Rajput and Tahir (1988) on Herb. Linn. No. 170.1 (LINN). According to García and Cafferty (2005), it has the annotation ‘C. europaea’ handwritten by Linnaeus and is an uncontroversial lectotype. The other Linnean variety of C. europaea is universally accepted at the species level as C. epithymum.

Species Vectored

Distribution

Cuscuta europaea is the most widespread species of Cuscuta subgenus Cuscuta. It is common in C and N Europe from sea level, whereas in S Europe, it is restricted to mountainous areas. Towards the east, it is apparently a common plant throughout Siberia with the easternmost populations near the Pacific coasts. Populations occur on the Japanese island of Hokkaido. It avoids the Central Asian deserts and appears in the Altai and Mongolia, Tian Shan, Pamir and the Himalayas towards SE Tibet and NE India. In SW Asia, it is common in Georgia, Armenia and Azerbaijan extending to Anatolia, Lebanese mountains, N Iran, NE Afghanistan and Pakistan. In Africa, it is very localized in northern Algeria and Libya.

Distribution Map

Distribution Table

History of Introduction and Spread

Cuscuta europaea is mostly limited to its native area of distribution and there are only few collections from N America (Maine and New York). The reports of the species in other states and countries are probably misidentifications.

Introductions

Introduced to	Introduced from	Year	Reason	Introduced by	Established in wild through natural reproduction	Established in wild through continuous restocking	References	Notes
New York			Crop production (pathway cause)		Yes		Costea and Nesom (2024)	Unknown origin and date of introduction. Date corresponds with the first herbarium collection. Originally from Europe or Asia
Maine		1897	Crop production (pathway cause)		Yes		Costea and Nesom (2024)	Unknown origin and date of introduction. Date corresponds with the first herbarium collection. Originally from Europe or Asia

Risk of Introduction

Cuscuta europaea grows on native wild plants, rarely on crops and therefore the likelihood of deliberate or accidental introduction is low. In spite of the improbable introduction and naturalization of C. europaea, all the species of the genus are frequently listed as prohibited, quarantine organisms. Holm et al. (1997) indicate that 25 countries have declared Cuscuta spp. as noxious, and that the movement of Cuscuta-infested material is prohibited in every state of the USA.

Means of Movement and Dispersal

Cuscuta europaea has dehiscent fruits and seeds lack any morphological dispersal syndrome, being assumed that they are dispersed to nearby areas by wind and water. The relationship of fruit dehiscence with dispersal capacity of Cuscuta is discussed in Ho and Costea (2018). Costea et al. (2016) showed that seeds of C. campestris can be dispersed to long distances by waterfowl endozoochory suggesting that other species of the genus can be spread this way. The wide natural distribution of C. europaea also suggests this possibility.

Human-assisted dispersal is possible with seeds transported by agricultural machinery used in the management of crop fields. Intentional introduction is relatively unlikely, though any Cuscuta species could occasionally be regarded as a botanical curiosity and introduced for this reason.

Pathway Causes

Pathway cause	Notes	Long distance	Local	References
Seed trade	Contaminated crop seeds. Very unlikely for C. europaea	Yes	Yes

Pathway Vectors

Pathway vector	Long distance	Local
Germplasm	Yes	Yes
Machinery and equipment	Yes	Yes
Water	No	Yes
Soil, sand and gravel	Yes	Yes
Plants or parts of plants	Yes	Yes

Plant Trade

Plant parts liable to carry the pest in trade/transport	Pest stages	Borne internally	Borne externally	Visibility of pest or symptoms
Flowers/Inflorescences/Cones/Calyx	weeds/seeds weeds/whole plants weeds/stems
Fruits (inc. pods)	weeds/seeds
Growing medium accompanying plants	weeds/seeds
True seeds (inc. grain)	weeds/seeds

Plant parts not known to carry the pest in trade/transport
Bark
Bulbs/Tubers/Corms/Rhizomes
Leaves
Roots
Seedlings/Micropropagated plants
Wood

Hosts/Species Affected

In Europe, the species has preference for Urtica dioica and Humulus lupulus but can be found growing on a great variety of other hosts. In Lithuania, it has been reported on 34 plant species, the most intensive growth being observed on U. dioica, Aegopodium podagraria, Fraxinus excelsior, Lamium album, Solidago canadensis and raspberry. Almost three times as many, and also larger, inflorescences were observed on U. dioica than on raspberry and A. podagraria (Gal'vidis, 1993). The host diversity is higher in Asia and, in some areas of the Himalayas, can parasitize medicinal and endangered species (Joshi and Gairola, 2003).

Although C. europaea is indiscriminately recorded as a serious weed in several countries (Holm et al., 1979), the range of crops affected is not well documented and probably not important. Rapparini and Campagna (1998) indicate sugarbeet as a major host in Italy but this and reports provided in other publications need to be considered carefully because misidentification with other weedy species such as C. campestris is probable.

Host Plants and Other Plants Affected

Host	Family	Host status	References
Achillea sp.		Wild host	Herbarium collections
Aegopodium podagraria (ground elder (UK))	Apiaceae	Wild host	Herbarium collections
Alhagi sp.		Wild host	Herbarium collections
Allium cepa (onion)	Liliaceae	Wild host	Herbarium collections
Alnus (alders)	Betulaceae	Wild host	Herbarium collections
Alyssum sp.		Wild host	Herbarium collections
Anaphalis sp.		Wild host	Herbarium collections
Anemone sp.		Wild host	Herbarium collections
Anemone spp.		Wild host	Herbarium collections
Anthyllis sp.		Wild host	Herbarium collections
Apium sp.		Wild host	Herbarium collections
Arabis sp.		Wild host	Herbarium collections
Artemisia vulgaris (mugwort)	Asteraceae	Wild host	Herbarium collections
Aster sp.		Wild host	Herbarium collections
Astragalus sp.		Wild host	Herbarium collections
Astragalus stipulatus	Fabaceae	Wild host	Herbarium collections
Atractylis sp.		Wild host	Herbarium collections
Berberis sp.		Wild host	Herbarium collections
Beta vulgaris (beetroot)	Chenopodiaceae	Wild host	Herbarium collections
Bistorta spp.		Wild host	Herbarium collections
Calystegia sp.		Wild host	Herbarium collections
Campanula sp.		Wild host	Herbarium collections
Centaurea sp.		Wild host	Herbarium collections
Chaerophyllum sp.		Wild host	Herbarium collections
Chenopodium sp.		Wild host	Herbarium collections
Cirsium sp.		Wild host	Herbarium collections
Clematis sp.		Wild host	Herbarium collections
Consenia sp.		Wild host	Herbarium collections
Convolvulus sp.		Wild host	Herbarium collections
Corydalis sp.		Wild host	Herbarium collections
Crataegus monogyna (hawthorn)	Rosaceae	Wild host	Herbarium collections
Cremanthodium spp.		Wild host	Herbarium collections
Crucianella sp.		Wild host	Herbarium collections
Dactylorhiza spp.		Wild host	Herbarium collections
Danthonia spp.		Wild host	Herbarium collections
Daphne sp.		Wild host	Herbarium collections
Daucus sp.		Wild host	Herbarium collections
Dipsacus sp.		Wild host	Herbarium collections
Epilobium sp.		Wild host	Herbarium collections
Eryngium sp.		Wild host	Herbarium collections
Eupatorium sp.		Wild host	Herbarium collections
Euphorbia sp.		Wild host	Herbarium collections
Euphrasia sp.		Wild host	Herbarium collections
Filipendula sp.		Wild host	Herbarium collections
Fraxinus spp.		Wild host	Herbarium collections
Galeopsis sp.		Wild host	Herbarium collections
Galium sp.		Wild host	Herbarium collections
Genista sp.		Wild host	Herbarium collections
Gentianella spp.		Wild host	Herbarium collections
Geranium sp.		Wild host	Herbarium collections
Heracleum sp.		Wild host	Herbarium collections
Heracleum spp.		Wild host	Herbarium collections
Humulus lupulus (hop)	Cannabaceae	Main	Herbarium collections
Hypericum sp.		Wild host	Herbarium collections
Indigofera sp.		Wild host	Herbarium collections
Lamium sp.		Wild host	Herbarium collections
Lamium spp.		Wild host	Herbarium collections
Lathyrus sp.		Wild host	Herbarium collections
Ligustrum sp.		Wild host	Herbarium collections
Linaria sp.		Wild host	Herbarium collections
Lolium sp.		Wild host	Herbarium collections
Lotus sp.		Wild host	Herbarium collections
Lupinus sp.		Wild host	Herbarium collections
Lysimachia sp.		Wild host	Herbarium collections
Medicago sp.		Wild host	Herbarium collections
Melampyrum sp.		Wild host	Herbarium collections
Melilotus sp.		Wild host	Herbarium collections
Mentha (mints)	Lamiaceae	Wild host	Herbarium collections
Myosotis sp.		Wild host	Herbarium collections
Nepeta sp.		Wild host	Herbarium collections
Nepeta sp.		Wild host	Herbarium collections
Pedicularis sp.		Wild host	Herbarium collections
Physalis sp.		Wild host	Herbarium collections
Picrorhiza spp.		Wild host	Herbarium collections
Pimpinella sp.		Wild host	Herbarium collections
Plantago sp.		Wild host	Herbarium collections
Plectranthus sp.		Wild host	Herbarium collections
Polygonum sp.		Wild host	Herbarium collections
Populus sp.	Salicaceae	Wild host	Herbarium collections
Potentilla sp.		Wild host	Herbarium collections
Prunus sp.		Wild host	Herbarium collections
Rhinanthus sp.		Wild host	Herbarium collections
Rhododendron sp.		Wild host	Herbarium collections
Ribes sp.		Wild host	Herbarium collections
Rosa sp.		Wild host	Herbarium collections
Rubus idaeus (raspberry)	Rosaceae	Wild host	Herbarium collections
Rubus spp.		Wild host	Herbarium collections
Rumex sp.		Wild host	Herbarium collections
Salix	Salicaceae	Wild host	Herbarium collections
Salvia sp.		Wild host	Herbarium collections
Sambucus sp.		Wild host	Herbarium collections
Scabiosa sp.		Wild host	Herbarium collections
Scrophularia sp.		Wild host	Herbarium collections
Selinum spp.		Wild host	Herbarium collections
Selinum spp.		Wild host	Herbarium collections
Sibbaldia sp.		Wild host	Herbarium collections
Silene sp.		Wild host	Herbarium collections
Solanum sp.		Wild host	Herbarium collections
Solidago spp.		Wild host	Herbarium collections
Sonchus sp.		Wild host	Herbarium collections
Stachys sp.		Wild host	Herbarium collections
Swertia sp.		Wild host	Herbarium collections
Swertia spp.		Wild host	Herbarium collections
Tanacetum sp.		Wild host	Herbarium collections
Thalictrum sp.		Wild host	Herbarium collections
Thermopsis sp.		Wild host	Herbarium collections
Tragopogon sp.		Wild host	Herbarium collections
Trifolium sp.		Wild host	Herbarium collections
Urtica dioica	Urticaceae	Main	Herbarium collections
Veronica sp.		Wild host	Herbarium collections
Vicia faba	Fabaceae	Wild host	Herbarium collections
Vicia sativa	Fabaceae	Wild host	Herbarium collections
Vincetoxicum sp.		Wild host	Herbarium collections

Growth Stages

Fruiting stage

Flowering stage

Vegetative growing stage

Diagnosis

Molecular identification with Sanger DNA sequencing can be used to identify seeds or sterile specimens. The DNA sequence data of the chloroplast rbcL and nuclear ribosomal 26S genes obtained by García et al. (2014) are reliable and can be used combined as barcode for identifying C. europaea. Reference sequences in GenBank include accession numbers KJ436644 (rbcL) and KJ400083 (26S).

The nuclear ITS region can also be used as a barcode for identifying C. europaea. García and Martín (2007) published a phylogeny of Cuscuta subgen. Cuscuta and these are reliable reference ITS sequences from this work in GenBank: DQ924602 (voucher from India), DQ924603 (voucher from Spain) and DQ924604 (voucher from Germany).

Similarities to Other Species/Conditions

Cuscuta europaea might be confused with other species that live in similar habitats. In Europe, the introduced C. gronovii (swamp dodder) also grows near river shores, wetland margins or alluvial forests. This species is native to N America but can be misidentified as C. europaea. In flower, both are easily distinguished from each other by numerous morphological features but the most evident are the elongated stigmas in C. europaea vs. capitate in C. gronovii. Sterile specimens can be separated by the marked protuberances on the stems just opposite to the haustoria in C. gronovii, typical of species of subgenus Grammica.

Some species of Cuscuta with elongated stigmas can be confused with C. europaea. In Europe, the most probable confusion is with C. epithymum but this species has acute calyx and corolla lobes, developed infrastaminal scales and styles and stigmas that together are longer than the ovary. Species of subgenus Monogynella such as C. lupuliformis, C. lehmanniana or C. monogyna have one style vs. two in C. europaea.

Habitat

Cuscuta europaea has a wide area of distribution, occupying diverse habitats. It has preference for non-saline and humid areas, near streams, rivers and nitrophilous grasslands. In the Mediterranean countries, with dry summers, it is found at higher altitudes but in areas with wet summer appears at lower altitudes frequently in altered and open areas. In Central Asian mountains, it is found in alpine meadows.

Habitat List

Category	Sub-Category	Habitat	Presence	Status
Terrestrial	Terrestrial - Managed	Cultivated / agricultural land	Present, no further details	Natural
Terrestrial	Terrestrial - Managed	Disturbed areas	Present, no further details	Natural
Terrestrial	Terrestrial - Managed	Rail / roadsides	Present, no further details	Natural
Terrestrial	Terrestrial - Managed	Urban / peri-urban areas	Present, no further details	Natural
Terrestrial	Terrestrial - Natural / Semi-natural	Riverbanks	Present, no further details	Natural
Terrestrial	Terrestrial - Natural / Semi-natural	Wetlands	Present, no further details	Natural

Biology and Ecology

Genetics

Cuscuta europaea is a diploid with chromosome number 2n=14 (García and Castroviejo, 2003; Guerra and García, 2004). Chromosomes are holocentric, lacking localized centromeres as all the other species of subgenus Cuscuta (Ibiapino et al., 2022). Oliveira et al. (2020) showed that the spindle attachment sites are not correlated with the discrete distribution of the histone variant CENH3 along the chromosomes suggesting a CENH3-free mechanism of kinetochore positioning.

Cuscuta europaea has satellite-rich heterochromatic genome regions resulting in heterochromatic bands along the chromosomes. Vondrak et al. (2021) used ultra-long read sequencing techniques to investigate the complex internal structure of these regions.

The chloroplast genome of C. europaea is much reduced (approximately 98,000 base pairs) compared to green relatives and lacking one of the inverted repeats (Pan et al., 2023).

García and Martín (2007) found almost identical ITS sequences from individuals of India and Europe suggesting a low genetic diversity in the species range and supported by the low morphological variation.

The species has not been reported as a parental for species of hybrid origin in the genus.

Reproductive Biology

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. europaea.

Wright et al. (2012) surveyed the diversity of pollen and ovule production in 128 species of Cuscuta and found a relation Pollen/Ovule of 232.6 for a specimen of C. europaea from Finland. It was assigned to category 3 of Cruden's (1977) mating system, suggesting that the species has facultative autogamous flowers. Low P/O ratios are characteristic of species of disturbed habitats in agreement with the ecology of C. europaea. Plitmann (1991) found a P/O of 409.1 for individuals from Lebanon and Turkey indicating that pollen production is a variable feature in C. europaea.

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. In eastern Lithuania, germination of C. europaea was shown to be abundant after rain at the end of May and beginning of June (Gal'vidis, 1993). 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 are reviewed by Parker and Riches, 1993). Connections are then formed by a bridge of tracheids with the host xylem, while connection with the phloem via plasmodesmata between searching hyphae and host parenchyma cells has also been confirmed by Dörr (1987). Once the haustorial connection is complete, new flower and shoot buds develop close by. Fritsche et al. (1958) provide detailed observations on the growth and flowering of C. europaea.

Environmental Requirements

Cuscuta europaea grows better under sunny and warm conditions tolerating climates with wet summers contrary to other species that prefer dry summers. It is found on hosts growing mostly on wet and nitrophilous soils requiring moist soil to germinate. The mainly temperate distribution of C. europaea suggests that this species is dependent on a cool or cold winter period for 'stratification' and breakage of seed dormancy. Summer temperature is important in the distribution of the species in N Europe (Verdcourt, 1947).

Climate

Climate type	Status	Description
Cfb - Maritime temperate climate	Preferred	Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year, warmest month average temp. < 22°C
Cwb - Maritime temperate climate	Preferred	Maritime temperate climate (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters, warmest month average temp. < 22°C)
Dfb - Warm summer continental or hemiboreal climate	Preferred	Warm summer continental or hemiboreal climate (Warm average temp. > 10°C, coldest month < 0°C, wet all year, warmest month average temp. < 22°C)
H - Highland climate	Tolerated	Highland climate (Average temp. of warmest month < 10°C due to altitude > 1500m)

Latitude/Altitude Ranges

Latitude North (°N)	Latitude South (°S)	Altitude lower (m)	Altitude upper (m)
65.8	25.95	0	5000

Air Temperature

Parameter	Lower limit (°C)	Upper limit (°C)
Mean annual temperature (°C)	8	22
Mean maximum temperature of hottest month (°C)	17	39
Mean minimum temperature of coldest month (°C)	-10	9

Rainfall

Parameter	Lower limit	Upper limit	Description
Dry season duration	0	9	number of consecutive months with <40 mm rainfall
Mean annual rainfall	250	1200	mm; lower/upper limits

Rainfall Regime

Summer

Uniform

Notes on Natural Enemies

A number of insects are known to attack Cuscuta species. Shinkarenko (1982) studied the natural enemies of five species of Cuscuta in the Axy-Dzhabalginsk Reserve, Kazakhstan, and found nine species of insects feeding on them. Some of them were not specific, as the larvae of the Lepidoptera genera Psorosa, Lycaena, Celastrina, Chlorissa and Eublemma. Baloch et al. (1967) found that the fly Melanagromyza cuscutae is specific to the genus Cuscuta and attempts to use this species as a means of biological control of C. europaea by augmentative release have been made in Kazakhstan (Julien and Griffiths, 1998). This fly is present in Asia and Europe (Tóth et al., 2004). CAB International (1987) provides information on insects and plant pathogens of Cuscuta and in addition to Melanagromyza cuscutae includes several species of curculionid genus Smicronyx and the moth Herpystis cuscutae although the latter apparently feeding only on C. reflexa in Pakistan (Baloch et al., 1969). Anderson (1974) first described some of the Smicronyx species listed on Cuscuta.

Aceria cuscutae [Eriophyes cuscutae], a mite feeding on Cuscuta epithymum in Europe (Molliard, 1909) might also be found on C. europaea. Several polyphagous species of the genus Aphis feed on Cuscuta, one of them A. cuscutae on dodders in N America (Blackman and Eastop, 2006). Other aphids found on Cuscuta include Brachyunguis cuscutae in Uzbekistan.

Fungal pathogens include Alternaria cuscutacidae (CAB International, 1987). Other Ascomycota isolated from Cuscuta are species of the genus Colletotrichum such as C. destructivum or C. gloeosporioides [Glomerella cingulata].

Natural enemies

Natural enemy	Type	Life stages	Specificity	References
Aceria cuscutae	Herbivore	Plants\|Whole plant	to genus	Molliard (1909)
Alternaria cuscutacidae	Parasite	Plants\|Whole plant	to genus	Rudakov (1961)
Aphis cuscutae	Herbivore	Plants\|Whole plant	to genus	Blackman and Eastop (2006)
Aphis fabae	Herbivore	Plants\|Whole plant	not specific	https://bladmineerders.nl
Brachyunguis cuscutae	Herbivore	Plants\|Whole plant	to genus	Blackman and Eastop (2006)
Celastrina argiolus	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Chlorissa pretiosaria	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Chlorissa viridata	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Eublemma polygramma	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Herpystis cuscutae	Herbivore	Plants\|Whole plant	to genus	Baloch et al. (1969)
Lycaena sp.	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Melanagromyza cuscutae	Parasite	Plants\|Whole plant	to genus	Baloch et al. (1967), Piwowarczyk et al. (2020)
Psorosa sp.	Herbivore	Plants\|Whole plant	not specific	Shinkarenko (1982)
Smicronyx albosquamosus	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx brevicornis	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx coecus	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx jungermanniae	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx nebulosus	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx pauperculus	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx smreczynskii	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl
Smicronyx syriacus	Parasite	Plants\|Stems	to genus	https://bladmineerders.nl

Impact Summary

Category	Impact
Animal/plant collections	None
Animal/plant products	None
Biodiversity (generally)	None
Crop production	Negative
Environment (generally)	None
Fisheries / aquaculture	None
Forestry production	None
Human health	None
Livestock production	None
Native fauna	None
Native flora	None
Rare/protected species	None
Tourism	None
Trade/international relations	None
Transport/travel	None

Impact

Holm et al. (1979) list C. europaea as a 'serious' weed in Afghanistan and Poland, and a 'principal' weed in Czechoslovakia and the former USSR. It is rarely a major weed over large areas, perhaps because of the lack of attack on Gramineae [Poaceae], and the cleaning effect of cereal crops in rotation. But once contact is established with the host phloem, Cuscuta becomes a powerful sink for metabolites, causing a severe drain on host resources and often completely preventing normal fruit development, as shown by Wolswinkel (1979) for C. europaea on faba bean (Vicia faba). Owing to this powerful metabolic sink effect, studied and described in detail by Wolswinkel and Ammerlaan (1983), the damage to infected hosts can be severe, to the extent of total crop loss. Less dry matter and ash were found in the leaves of parasitized Urtica dioica and Aegopodium podagraria than in those of healthy plants. Leaves of parasitized U. dioica plants contained 8.5% less chlorophyll than uninfested ones (Gal'vidis, 1993). Perhaps the crop most seriously affected is sugarbeet in Italy, the former Yugoslavia and eastern Europe. There is also further economic loss when crop produce, such as clover or lucerne seed, intended for export, is rejected or has to be expensively cleaned. There are occasional reports of toxicity to livestock from Cuscuta species, including toxicity to horses from C. europaea (Pergat and Stolyarova, 1961).

Economic Impact

The economic impact of C. europaea has not been evaluated but since the species is rarely found on crops it is probably low. Holm et al. (1979) list C. europaea as a 'serious' weed in Afghanistan and Poland, and a 'principal' weed in Czechoslovakia and the former USSR. However, it is not clear whether the species referred to is C. europaea or some other weedy species of the genus. Wolswinkel (1979) showed that once contact is established with the host phloem, C. europaea becomes a powerful sink for metabolites, causing a severe drain on host resources and often completely preventing normal fruit development on faba bean (Vicia faba). Therefore, this species might have local economic impact on faba bean or other crops but there is not a quantitative evaluation, probably because it is uncommon. There are occasional reports of toxicity to livestock from Cuscuta species, including toxicity to horses (Pergat and Stolyarova, 1961).

Impact: Environmental

With a few exceptions, C. europaea is not known to have caused any significant impact on habitats or biodiversity. Joshi and Gairola (2003) report C. europaea growing on endangered and medicinal species in the Valley of Flowers (Uttarakhand, India), but since it is native in the area might not suppose a real threat and actually have ecological significance.

Impact: Social

Cuscuta europaea is not known to have caused any significant social impact.

Risk and Impact Factors

Invasiveness

Has a broad native range

Abundant in its native range

Fast growing

Has high reproductive potential

Has propagules that can remain viable for more than one year

Reproduces asexually

Impact outcomes

Host damage

Negatively impacts agriculture

Impact mechanisms

Competition - monopolizing resources

Pest and disease transmission

Parasitism (incl. parasitoid)

Rapid growth

Likelihood of entry/control

Difficult to identify/detect as a commodity contaminant

Difficult/costly to control

Uses

Cuscuta species are frequently used as a research tool, to create a bridge between different plants for transmission of viruses and mycoplasma-like organisms from one host to another (see Dawson et al., 1994). Eppler (1992) reports on the use of C. europaea to obtain transmission of a virus in hops (Humulus lupulus). Cuscuta europaea has been reported to be a source of an immuno-stimulant compound of pharmacological interest (Stanilova et al., 2001).

Detection and Inspection

The presence of invasive Cuscuta in crop fields is evident for its distinct thread-like and profusely branched stems. However, an accurate identification of the species in the field is possible only in flower. A reference key for the identification of C. europaea in N America is in Costea and Nesom (2024). In its native area of distribution, Feinbrun (1972) for Europe, Butkov (1974) for the territory of the former USSR, Plitmann (1978) for Turkey and SW Asia, and Yuncker (1932) for the world.

Prevention and Control

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.

Cuscuta europaea is rarely found on crops. The following prevention and control measures are general for species of Cuscuta.

Cultural Control

Use of clean crop seed is very important. 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 (see Parker and Riches, 1993). Deep shade suppresses the coiling and attachment of Cuscuta but in the case of C. europaea, this measure could not be so effective because this species is more adapted to shade than other species.

Mechanical Control

The young seedlings of Cuscuta 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. Cuscuta 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.

Chemical Control

There is relatively little information on the use of herbicides against C. europaea, but good results have been reported for ethofumesate in sugar beet; propyzamide in sugar beet and onions; and a mixture of chlorthal-dimethyl with chlorpropham in onions and carrots (Foschi and Rapparini, 1977; Rapparini and Campagna, 1998). 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, pendimethalin, fluchloralin, butralin, etc., in lucerne and some other legumes. These might be expected to be equally effective against C. europaea.

Biological Control

Biological control of C. europaea has been attempted in Kazakhstan, by augmentative release of Melanagromyza cuscutae but the outcome is not certain (Julien and Griffiths, 1998). This insect has also failed to give convincing results on other species. The biology and host range of M. cuscutae were studied by Baloch et al. (1967) and reviewed by Spencer (1973). Other attempts at biological control of Cuscuta spp. by insects have mainly involved the gall-forming weevils Smicronyx spp.; S. tartaricus has given encouraging results for control of C. europaea in Kazakhstan when introduced from one region to another (Shinkarenko, 1982). Among pathogens Rudakov (1961) proposed of Alternaria cuscutacidae to control Cuscuta on crop fields and a US patent proposed a mycoherbicidal inoculum with spores of Fusarium tricinctum and Alternaria sp. for controlling the growth of Cuscuta (US4915726A; Bewick et al., 1990). Prospects for biological control of C. europaea and other species have been reviewed by Girling et al. (1979).

Integrated Control

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.

Links to Websites

Website	URL	Comment
Flora of North America	http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=108730	Keys and descriptions of Cuscuta species in N America, including C. approximata where it is introduced.
Plant Parasites of Europe. Leafminers, galls and fungi	https://bladmineerders.nl/	Searchable database on plant leafminers, causers of plant galls and parasitic microfungi. Natural enemies of Cuscuta and references are included.

References

Anderson, D.M., 1974. Some species of Smicronyx (Coleoptera:Curculionidae) associated with Cuscuta species (Convolvulaceae) in Pakistan.Proceedings of the Entomological Society of Washington, 76(4):359-374.

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