Cyperus rotundus (purple nutsedge)
- 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
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Economic Impact
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Links to Websites
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Cyperus rotundus L.
Preferred Common Name
- purple nutsedge
Other Scientific Names
- Chlorocyperus rotundus (L.) Palla
- Chorocyperus salaamensis Palla
- Cyperus agresti Willd. ex Spreng. & Link
- Cyperus arabicus Ehrenb. ex Boeck.
- Cyperus bicolor Vahl
- Cyperus bifax C.B.Clarke
- Cyperus bulbosotoloniferus Mig.
- Cyperus comosus Sm.
- Cyperus disruptus C.B.Clarke
- Cyperus herbicavus Melliss
- Cyperus hexastachyos Rottb.
- Cyperus hildra Poir.
- Cyperus hydra Michx.
- Cyperus laevissimus Steud.
- Cyperus leptostachyus Griff.
- Cyperus merkeri C.B.Clarke
- Cyperus micreilema Steud.
- Cyperus nubicus C.B.Clarke
- Cyperus ochreoides Steud.
- Cyperus oliganthus Gand.
- Cyperus olivaris O.Targ.Tozz.
- Cyperus platystachys Cherm.
- Cyperus procerulus Nees
- Cyperus pseudovariegatus Boeck.
- Cyperus purpureovariegatus Boeck.
- Cyperus radicosus Sm.
- Cyperus rudioi Boeckeler
- Cyperus taylorii C.B.Clarke
- Cyperus tetrastachyos Desf.
- Cyperus tuberosus Rottb.
- Cyperus weinlandii Kuk.
- Cyperus yoshinagae Ohwi
- Pycreus rotundus (L.) Hayek
- Schoenus tuberosus Burm.f.
International Common Names
- English: coco grass; java grass; nut sedge; nutgrass; purple nut-grass; purple nut-sedge; red grass; red nut sedge; water grass
- Spanish: castanuela; cebolleta; chufa; chufila; cipero; contra yerba; corocilla; cortadera; jonquillo; juncea; lengua de gallina; negrillo; paraquita; pasto bolita; totorilla
- French: souchet an forme d'olive
- Chinese: xiang fu zi
- Portuguese: alho-bravo; capim-alho; capim-dandá; junca de conta; tiririca; tiririca-vermelha
Local Common Names
- Bangladesh: motha
- Brazil: alho; alho-bravo; capim-alho; capim-dandá; junca; junca-aromática; tiririca; tiririca-comum; tiririca-vermelha; tres-quinas
- Cambodia: smao kravanh chrouk
- Chile: almendra de tierra; chufa; coquillo
- Colombia: cortadera
- Cuba: ajo cimarron; basarillo; caramana; cebolleta; cebolleta de la provincia; cebollin; coquito; corojillo; corojito; juncia redonda; macaguita; yerba del rinon
- Dominican Republic: afio; caramaná; coquillo; junquillo de sabana; ronquillo; saqui-saco
- Egypt: seid
- Fiji: soronakabani; vucesa
- Germany: Apotheker-Cypergras; Asiatisches-Cypergras; Runde-Cypergras; Runde-Zyperwurzel
- Greece: kupere
- India: deela; gantola; korai; nagar motha
- Indonesia: teki
- Iraq: oyarslan
- Italy: cipero orientale; cipero rotondo; stancia rotonda
- Jamaica: nut-grass
- Japan: hamasuge
- Kenya: moikut
- Malaysia: rumput haliya hitan
- Mexico: cebollin; pimientillo
- Myanmar: monhnyin-bin
- Pakistan: notha
- Peru: coco; coquillo; coquito
- Philippines: balisanga; boto-botonis; mala-apulid; mutha; sur-sur
- Puerto Rico: coqui; coquillo
- Samoa: mumuta
- South Africa: rooiuintjie; uintjie
- Sri Lanka: kalanthi
- Suriname: adroe
- Taiwan: hsiang-fu-tzu
- Thailand: haew moo; ya-haeo-mu
- Tonga: pakopako
- Turkey: topalak
- CYPRO (Cyperus rotundus)
Summary of InvasivenessTop of page
C. rotundus has been considered as one of the world’s worst weeds. It has been reported in more than 90 countries where it grows as a weed infesting at least 52 different crops worldwide (Holm et al. 1977). It grows in all types of soils and can also survive high temperatures. C. rotundus can be found in a wide variety of habitats including cultivated fields, waste areas, roadsides, pastures, riverbanks, sandbanks, irrigation channels, river and stream shores and natural areas. It is considered a headache for gardeners and farmers because of its insidious and rapid growth and its herbicide tolerance. C. rotundus produces an extensive system of underground tubers from which they can regenerate and consequently is very difficult to control once it is established (USDA-NRCS, 2014).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Cyperales
- Family: Cyperaceae
- Genus: Cyperus
- Species: Cyperus rotundus
Notes on Taxonomy and NomenclatureTop of page
Cyperus rotundus is the universally accepted name. Several subspecies are described though they are rarely recognized in literature on the weed. Haines and Lye (1983) describe four subspecies from East Africa, rotundus, merkeri, taylorii and tuberosus, but this is not accepted by all authors. Hutchinson et al. (1972), for example, recognize C. tuberosus Rottb. as a species, not as a subspecies of C. rotundus. Variations in C. rotundus have led to descriptions of ecotypes, such as those from India based on glume colour (Ranade and Burns, 1925), morphotypes (Wills, 1998) and chemotypes, such as those from Japan and China based on sesquiterpenes in tubers (Komai and Ueki, 1981).
DescriptionTop of page
C. rotundus is a highly variable perennial sedge. Flowering stems are erect, up to 60 cm tall, 3-sided, smooth with swollen bases (basal bulbs). The leaves have a distinct midrib, are linear, usually shorter than the flowering stem, up to 7 mm wide and emerge from a sheath around the shoot base. The inflorescence is a terminal, open umbel subtended by several leafy bracts. Several unequal rays, 2-6 cm long, support 3-8 reddish-brown to purplish-brown, flattened spikelets, 1-2 cm long and 2 mm wide, each with up to 30 glumes, 3.5-4 mm long. Roots are fibrous. Rhizomes are wiry, dark and persistent, connecting a network of daughter shoots and tubers. The tubers are dark brown to black, irregularly shaped and 1-2 cm long when fully grown. Each tuber has an apical bud and several lateral buds. The fruit (often, but erroneously, known as the seed) is a 3-angled achene, 1.5 mm long, dark brown or black.
Plant TypeTop of page Annual
Grass / sedge
DistributionTop of page
C. rotundus is thought by some authorities to have originated in India but others believe that the origins are more widespread, including northern and eastern Australia (Parsons and Cuthbertson, 1992). At present, the most widely accepted distribution range considers this species as native to the tropical and subtropical Old World, principally Africa and Eurasia (Govaerts, 2014; USDA-ARS, 2014). Holm et al. (1977) have recorded its occurrence in 92 countries but its presence can be assumed in all countries of the tropics and subtropics.
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||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Bangladesh||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Bhutan||Present||Native||Parker, 1992; Govaerts, 2014|
|Brunei Darussalam||Present||Invasive||Moody, 1989; Waterhouse, 1993||Listed as both native and introduced|
|Cambodia||Present||Invasive||Holm et al., 1979; Waterhouse, 1993||Listed as both native and introduced|
|Chagos Archipelago||Present||Introduced||Invasive||Whistler, 1996|
|-Anhui||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Chongqing||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Fujian||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Gansu||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Guangdong||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Guangxi||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Guizhou||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Hainan||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Hebei||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Henan||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Hubei||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Hunan||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Jiangsu||Present||Native||Guang, 1996; Flora of China Editorial Committee, 2014||Weed|
|-Jiangxi||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Liaoning||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Shaanxi||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Shandong||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Shanxi||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Sichuan||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Tibet||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Yunnan||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|-Zhejiang||Present||Native||Flora of China Editorial Committee, 2014||Weed|
|Christmas Island (Indian Ocean)||Present||Introduced||Invasive||Swarbrick, 1997|
|Cocos Islands||Present||Native||Govaerts, 2014|
|India||Present||Holm et al., 1979|
|-Andaman and Nicobar Islands||Present||Native||Govaerts, 2014|
|-Arunachal Pradesh||Present||Native||Govaerts, 2014|
|-Jammu and Kashmir||Present||Introduced||Invasive||Khuroo et al., 2007||Listed as invasive in Kashmir|
|Indonesia||Present||Holm et al., 1979; Waterhouse, 1993|
|-Nusa Tenggara||Present||Native||Govaerts, 2014|
|Iran||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Iraq||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Israel||Present||Native||Holm et al., 1979; Govaerts, 2014|
|-Honshu||Present||Numata et al., 1975|
|-Kyushu||Present||Numata et al., 1975|
|-Ryukyu Archipelago||Present||Numata et al., 1975|
|-Shikoku||Present||Numata et al., 1975|
|Jordan||Present||Holm et al., 1979|
|Korea, DPR||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Korea, Republic of||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Laos||Present||Moody, 1989; Waterhouse, 1993|
|Lebanon||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Malaysia||Present||Holm et al., 1979; Waterhouse, 1993|
|-Peninsular Malaysia||Present||Native||Govaerts, 2014|
|-Sarawak||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Myanmar||Present||Moody, 1989; Waterhouse, 1993; Govaerts, 2014|
|Nepal||Present||Native||Moody, 1989; Govaerts, 2014|
|Pakistan||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Philippines||Present||Holm et al., 1979; Waterhouse, 1993|
|Saudi Arabia||Present||Chaudhary and Akram, 1987; Govaerts, 2014|
|Sri Lanka||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Taiwan||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Thailand||Present||Invasive||Holm et al., 1979; Waterhouse, 1993||Listed as both native and introduced|
|Turkey||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Vietnam||Present||Invasive||Holm et al., 1979; Waterhouse, 1993||Listed as both native and introduced|
|Yemen||Present||Chaudhary and Revri, 1983; Govaerts, 2014|
|Angola||Present||Holm et al., 1979; Govaerts, 2014|
|Burkina Faso||Present||Hutchinson et al., 1972; Govaerts, 2014|
|Cameroon||Present||Holm et al., 1979; Govaerts, 2014|
|Cape Verde||Present||Native||Govaerts, 2014|
|Central African Republic||Present||Native||Govaerts, 2014|
|Chad||Present||Holm et al., 1979; Govaerts, 2014|
|Congo||Present||Holm et al., 1979; Govaerts, 2014|
|Congo Democratic Republic||Present||Native||Govaerts, 2014|
|Côte d'Ivoire||Present||Holm et al., 1979; Govaerts, 2014|
|Egypt||Present||Holm et al., 1979; Govaerts, 2014|
|Equatorial Guinea||Present||Native||Govaerts, 2014|
|Ethiopia||Present||Holm et al., 1979; Govaerts, 2014|
|Gabon||Present||Holm et al., 1979; Govaerts, 2014|
|Ghana||Present||Holm et al., 1979; Govaerts, 2014|
|Guinea||Present||Holm et al., 1979; Govaerts, 2014|
|Kenya||Present||Holm et al., 1979; Govaerts, 2014|
|Madagascar||Present||Holm et al., 1979; Govaerts, 2014|
|Mali||Present||Holm et al., 1979; Govaerts, 2014|
|Mauritania||Present||Holm et al., 1979; Govaerts, 2014|
|Mauritius||Present||Holm et al., 1979; Govaerts, 2014|
|Morocco||Present||Native||Holm et al., 1979; Govaerts, 2014|
|Mozambique||Present||Holm et al., 1979; Govaerts, 2014|
|Niger||Present||Holm et al., 1979; Govaerts, 2014|
|Nigeria||Present||Holm et al., 1979; Govaerts, 2014|
|Rodriguez Island||Present||Native||Govaerts, 2014|
|Saint Helena||Present||Native||Govaerts, 2014|
|Senegal||Present||Holm et al., 1979; Govaerts, 2014|
|Seychelles||Present||Robertson, 1989; Govaerts, 2014|
|Sierra Leone||Present||Hutchinson et al., 1972; Govaerts, 2014|
|South Africa||Present||Holm et al., 1979; Govaerts, 2014|
|-Canary Islands||Present||Govaerts, 2014|
|Sudan||Present||Holm et al., 1979; Govaerts, 2014|
|Swaziland||Present||Holm et al., 1979; Govaerts, 2014|
|Tanzania||Present||Holm et al., 1979; Govaerts, 2014|
|Tunisia||Present||Holm et al., 1979; Govaerts, 2014|
|Uganda||Present||Holm et al., 1979; Govaerts, 2014|
|Western Sahara||Present||Native||Govaerts, 2014|
|Zambia||Present||Holm et al., 1979; Govaerts, 2014|
|Zimbabwe||Present||Holm et al., 1979; Rambakudzibga, 1999; Govaerts, 2014|
|Bermuda||Present||Holm et al., 1979|
|Mexico||Present||Introduced||Invasive||Holm et al., 1979; Vibrans, 2009||Weed|
|-Alabama||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Arizona||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Arkansas||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-California||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-District of Columbia||Present||Introduced||USDA-NRCS, 2014|
|-Florida||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Georgia||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Hawaii||Present||Introduced||Invasive||Wagner et al., 1999|
|-Louisiana||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Mississippi||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-New Jersey||Present||Introduced||USDA-NRCS, 2014|
|-New York||Present||Introduced||USDA-NRCS, 2014|
|-North Carolina||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Oregon||Present||Introduced||Invasive||USDA-NRCS, 2014||Quarantine weed|
|-South Carolina||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Tennessee||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Texas||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
|-Virginia||Present||Lorenzi and Jeffery, 1987; USDA-NRCS, 2014|
Central America and Caribbean
|British Virgin Islands||Present||Introduced||Invasive||Acevedo-Rodriguez and Strong, 2012|
|Cayman Islands||Present||Introduced||Govaerts, 2014||Naturalised|
|Costa Rica||Present||Holm et al., 1979; Gómez-Laurito, 2003|
|Cuba||Present||Holm et al., 1979; Govaerts, 2014|
|Curaçao||Present||Introduced||Acevedo-Rodriguez and Strong, 2012|
|Dominican Republic||Present||Holm et al., 1979; Acevedo-Rodriguez and Strong, 2012|
|El Salvador||Present||Introduced||Govaerts, 2014||Naturalised|
|Guatemala||Present||Holm et al., 1979; Govaerts, 2014|
|Haiti||Present||Introduced||Acevedo-Rodriguez and Strong, 2012|
|Honduras||Present||Holm et al., 1979; Govaerts, 2014|
|Jamaica||Present||Holm et al., 1979; Govaerts, 2014|
|Netherlands Antilles||Present||Introduced||Govaerts, 2014||Naturalised|
|Nicaragua||Present||Holm et al., 1979; Govaerts, 2014|
|Panama||Present||Holm et al., 1979; Govaerts, 2014|
|Puerto Rico||Present||Holm et al., 1979; Acevedo-Rodriguez and Strong, 2012|
|Saint Lucia||Present||Introduced||Govaerts, 2014||Naturalised, very common|
|Trinidad and Tobago||Present||Holm et al., 1979; Govaerts, 2014|
|United States Virgin Islands||Present||Introduced||Invasive||Acevedo-Rodriguez and Strong, 2012|
|Argentina||Present||Holm et al., 1979; Govaerts, 2014|
|Bolivia||Present||Holm et al., 1979; Govaerts, 2014|
|-Espirito Santo||Present||Lorenzi, 1982; I3N-Brasil, 2014|
|-Fernando de Noronha||Present||Lorenzi, 1982|
|-Mato Grosso||Present||Lorenzi, 1982|
|-Mato Grosso do Sul||Present||Lorenzi, 1982|
|-Minas Gerais||Present||Lorenzi, 1982; I3N-Brasil, 2014|
|-Paraiba||Present||Lorenzi, 1982; I3N-Brasil, 2014|
|-Parana||Present||Lorenzi, 1982; I3N-Brasil, 2014|
|-Rio de Janeiro||Present||Lorenzi, 1982|
|-Rio Grande do Norte||Present||Lorenzi, 1982|
|-Rio Grande do Sul||Present||Lorenzi, 1982|
|-Santa Catarina||Present||Lorenzi, 1982|
|-Sao Paulo||Present||Lorenzi, 1982|
|Chile||Present||Holm et al., 1977; Holm et al., 1979|
|Colombia||Present||Holm et al., 1977; Holm et al., 1979|
|-Galapagos Islands||Present||Introduced||Invasive||Govaerts, 2014|
|French Guiana||Present||Introduced||Govaerts, 2014||Naturalised|
|Paraguay||Present||Holm et al., 1977; Holm et al., 1979|
|Peru||Present||Holm et al., 1979; Govaerts, 2014|
|Suriname||Present||Holm et al., 1979; Govaerts, 2014|
|Uruguay||Present||Holm et al., 1977; Holm et al., 1979|
|Venezuela||Present||Holm et al., 1979; Govaerts, 2014|
|Albania||Present||de Filippes, 1980; Govaerts, 2014|
|Bulgaria||Present||de Filippes, 1980; Govaerts, 2014|
|Czech Republic||Present||Introduced||DAISIE, 2014|
|France||Present||Holm et al., 1979; Govaerts, 2014|
|-Corsica||Present||de Filippes, 1980; Govaerts, 2014|
|Greece||Present||Holm et al., 1979; Govaerts, 2014|
|-Crete||Present||de Filippes, 1980|
|Italy||Present||Holm et al., 1979|
|-Sardinia||Present||de Filippes, 1980|
|-Sicily||Present||de Filippes, 1980|
|Portugal||Present||Holm et al., 1979; Govaerts, 2014|
|-Azores||Present||de Filippes, 1980; DAISIE, 2014|
|Russian Federation||Present||Native||Govaerts, 2014|
|Spain||Present||Holm et al., 1979; DAISIE, 2014|
|-Balearic Islands||Present||de Filippes, 1980; Govaerts, 2014|
|Switzerland||Present||de Filippes, 1980; DAISIE, 2014|
|Yugoslavia (former)||Present||Holm et al., 1979; Govaerts, 2014|
|American Samoa||Present||Introduced||Invasive||Space and Flynn, 2000|
|Australia||Present||de Filippes, 1980|
|-Australian Northern Territory||Present||Parsons and Cuthbertson, 1992; USDA-ARS, 2014|
|-New South Wales||Present||Parsons and Cuthbertson, 1992; USDA-ARS, 2014|
|-Queensland||Present||Parsons and Cuthbertson, 1992; USDA-ARS, 2014|
|-South Australia||Present||Parsons and Cuthbertson, 1992; USDA-ARS, 2014|
|-Victoria||Present||Parsons and Cuthbertson, 1992|
|-Western Australia||Present||Parsons and Cuthbertson, 1992; Govaerts, 2014|
|Cook Islands||Present||Introduced||Invasive||Space and Flynn, 2002|
|Fiji||Present||Holm et al., 1979; Smith, 1979|
|French Polynesia||Present||Introduced||Invasive||Florence et al., 2013|
|Kiribati||Present||Introduced||Invasive||Space et al., 2004|
|Marshall Islands||Present||Introduced||Invasive||Fosberg et al., 1987|
|Micronesia, Federated states of||Present||Introduced||Invasive||Herrera et al., 2010|
|Nauru||Present||Introduced||Invasive||Fosberg et al., 1987|
|New Caledonia||Present||Introduced||Invasive||MacKee, 1994; Govaerts, 2014|
|New Zealand||Present||Holm et al., 1979; Govaerts, 2014|
|Norfolk Island||Present||Introduced||Invasive||Orchard, 1994|
|Northern Mariana Islands||Present||Govaerts, 2014|
|Palau||Present||Introduced||Invasive||Space et al., 2003|
|Papua New Guinea||Present||Henty and Pritchard, 1975; Govaerts, 2014|
|Samoa||Present||Sauerborn and Sauerborn, 1984; Space and Flynn, 2002|
|Solomon Islands||Present||Invasive||Shine et al., 2003|
|Tonga||Present||Whistler, 1983; Space and Flynn, 2001|
|US Minor Outlying Islands||Present||Introduced||Invasive||Wagner et al., 1999|
|Vanuatu||Present||Introduced||Invasive||Shine et al., 2003|
|Wake Island||Present||Introduced||Invasive||Fosberg et al., 1987|
|Wallis and Futuna Islands||Present||Introduced||Invasive||Meyer, 2007|
History of Introduction and SpreadTop of page
C. rotundus is thought to have originated in Southeastern Asia and from there it was spread to the rest of the world during the last 2000 years. It has been used by ancient people in Africa (i.e., Nile Valley), China, and eastern Mediterranean as food, perfume, and medicine for centuries. For example, this species first appeared in a Chinese medicine book around 500 AD (Negbi, 1992). The most likely method of introduction of this species into new habitat could be related to human activities. Seeds, tubers, and rhizomes may have been introduced as a contaminant in soil, mud, agricultural machinery, fodder, pastures, and crop seeds (Holm et al., 1977). In the United States, it is considered that it was unintentionally introduced during the 1800s (USDA-NRCS, 2014). Since the 1880s, this species appears in collections made on islands in the West Indies (US National Herbarium).
Risk of IntroductionTop of page
The risk of introduction of C. rotundus is very high. This species is highly mobile and highly adaptable to different environments. It also benefits from human-related activities. Consequently it is considered one of the “world’s worst weeds” with the potential to negatively impact agriculture and natural ecosystems by displacing native plants or by changing the availability of food or shelter for native animals. This rapidly growing plant can quickly form dense colonies due to its ability to produce an extensive system of rhizomes and tubers. Thus, its likelihood of invading new habitats remains high.
HabitatTop of page
C. rotundus is widespread in the tropics and subtropics, growing in almost every soil type, altitude, humidity, soil moisture and pH, but not in soils with a high salt content (Holm et al., 1977). Its range at increasing latitudes and altitudes is limited by cold temperatures. It occurs in cultivated fields, fallow land, neglected areas, road and rail sides, banks of irrigation canals and streams, edges of woods and sand dunes. Generally, it does not tolerate shade.
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Cultivated / agricultural land||Present, no further details||Natural|
|Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Managed forests, plantations and orchards||Present, no further details||Natural|
|Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Managed grasslands (grazing systems)||Present, no further details||Natural|
|Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details||Natural|
|Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Rail / roadsides||Present, no further details||Natural|
|Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Urban / peri-urban areas||Present, no further details||Natural|
|Terrestrial ‑ Natural / Semi-natural||Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|Natural grasslands||Present, no further details||Natural|
|Riverbanks||Present, no further details||Harmful (pest or invasive)|
|Riverbanks||Present, no further details||Natural|
|Wetlands||Present, no further details||Harmful (pest or invasive)|
|Wetlands||Present, no further details||Natural|
|Coastal areas||Present, no further details||Harmful (pest or invasive)|
|Coastal areas||Present, no further details||Natural|
|Irrigation channels||Present, no further details||Harmful (pest or invasive)|
|Irrigation channels||Present, no further details||Natural|
|Rivers / streams||Present, no further details||Harmful (pest or invasive)|
|Rivers / streams||Present, no further details||Natural|
Hosts/Species AffectedTop of page
Holm et al. (1977) state that C. rotundus has been reported as a weed of 52 crops including vegetables and ornamentals. Some examples are cited in the list of hosts but, in reality, this weed can occur in virtually all crops grown within its range.
Host Plants and Other Plants AffectedTop of page
|Agave sisalana (sisal hemp)||Agavaceae||Other|
|Allium cepa (onion)||Liliaceae||Other|
|Arachis hypogaea (groundnut)||Fabaceae||Main|
|Camellia sinensis (tea)||Theaceae||Other|
|Capsicum annuum (bell pepper)||Solanaceae||Other|
|Cocos nucifera (coconut)||Arecaceae||Other|
|Corchorus olitorius (jute)||Tiliaceae||Main|
|Glycine max (soyabean)||Fabaceae||Other|
|Oryza sativa (rice)||Poaceae||Main|
|Saccharum officinarum (sugarcane)||Poaceae||Main|
|Solanum lycopersicum (tomato)||Solanaceae||Other|
|Sorghum bicolor (sorghum)||Poaceae||Other|
|Syzygium aromaticum (clove)||Myrtaceae||Other|
|Triticum aestivum (wheat)||Poaceae||Other|
|Zea mays (maize)||Poaceae||Main|
Biology and EcologyTop of page
Descriptions of the biology and ecology of C. rotundus can be found in Ranade and Burns (1925), Holm et al. (1977), Mercado (1979), Jha and Sen (1985) and Parsons and Cuthbertson (1992).
The typical life cycle of C. rotundus starts with growth of the apical bud of a tuber. As the tuber shoot extends, it swells to form a basal bulb (sometimes called a corm), usually near the soil surface, from which an aerial shoot and roots are produced. Up to three, or slightly more, rhizomes grow out of the basal bulb and produce tubers or new basal bulbs and daughter shoots. Rhizomes from the daughter shoots produce tubers from which new rhizomes and tubers develop. Eventually, branched chains of rhizomes and tubers become an extensive, underground network. Meanwhile, the new shoots grow and produce flowers within 3-8 weeks of emergence if stimulated by short photoperiods of 6-8 hours. Most seeds of C. rotundus are not viable; germination seldom averages more than 1-5 % (Holm et al., 1977) though this may be significant when seed production can exceed 100 million/ha in a single year.
Tuber dormancy is high on undisturbed sites and may last for at least 7 years (Parsons and Cuthbertson, 1992). Fragmentation of the rhizome/tuber network by cultivation breaks the dormancy imposed by a growing tuber on others in the same chain. Hence, cultivation stimulates the growth of C. rotundus. Large populations of shoots and tubers can develop from a single tuber; as many as 600 plants have been produced in a single year. Horowitz (1972) has reported that 2-3 million tubers per hectare per week can be produced during active growing periods, yielding 30-40 million tubers/ha. Forty tonnes of underground organs have been produced on 1 hectare in a year, giving C. rotundus a phenomenal capacity for vegetative reproduction. Most tubers are found in the upper 15 cm of soil but they can grow down to 30 cm or more in favourable conditions. Neeser et al. (1997) found that a tuber population has a half-life of 16 months and a predicted longevity (99% mortality) of 42 months.
C. rotundus has C4 metabolism which supposedly makes it increasingly competitive when temperatures and light intensity rise (Black et al., 1969). It has low tolerance of shade, a property that can be exploited in controlling this weed by crops with dense canopies (Rambakudzibga, 1999). Temperature has a marked effect on the germination of tubers. Sprouting has been reported at temperatures of 13-43°C but the range varies with biotype. Desiccation kills tubers but the duration and temperature of the drying period affects this process. The critical moisture level for tuber germination seems to be in the region of 11.5-15% (Jha and Sen, 1985).
Dispersal of C. rotundus occurs when tubers are moved by tillage equipment or other farm machinery. Flood waters may also carry the tubers. Contaminated soil in nursery stock is an avoidable but common method of dispersal. Under natural conditions, a population of C. rotundus extends its boundary by a few metres in a year. Spread by seed is generally regarded as being unimportant.
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
|Fusarium oxysporum||Pathogen||Uttar Pradesh|
Notes on Natural EnemiesTop of page See section on Biological Control.
Means of Movement and DispersalTop of page
Natural Dispersal (non-biotic)
Tubers of C. rotundus can be moved by water from the banks of drainage and irrigation channels or by the flooding of fields.
Spread of C. rotundus by seed is generally considered to be unimportant.
Dispersal of C. rotundus occurs when tubers are moved by tillage equipment or other farm machinery. Tubers and, indeed, living shoots can be dispersed in soil attached to transplanted material, such as trees taken from a nursery.
Pathway VectorsTop of page
|Soil, sand and gravel||Soil attached to the roots of transplanted material, e.g. tree nursery stock||Yes|
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||roots||Yes||Pest or symptoms usually visible to the naked eye|
Economic ImpactTop of page
In their survey of the world's weeds, Holm et al. (1977) deduced that C. rotundus was the worst, based on its occurrence in 52 crops in 92 countries and its capacity to cause substantial yield losses. In a later publication (Holm et al., 1979) it was listed as a 'serious' or 'principal' weed in no less than 70 countries, substantially more than any other species. Losses are caused largely as a result of competition for nutrients (for example, Rochecouste, 1956; Bhardwaj and Verma, 1968) and the competitive effects can, to some degree, be counteracted by adding extra fertilizer, especially nitrogen (Horowitz, 1973a, b). In other cases, however, additional nitrogen may exaggerate the losses, for example, in upland rice (Okafor and de Datta, 1976), radish (Santos et al., 1998) and pepper (Morales-Payan et al., 1998). It is presumed that in these cases the extra vigour of the weed in a relatively low growing crop causes competition for light. Competition for water can also be important, as shown in Phaseolus bean, when yields were reduced by 80% in a dry season but by only 50% in a wet season (William, 1973). Additionally there is evidence for an allelopathic effect that cannot be reversed even under optimal conditions of nutrient, light and moisture. In this respect, Horowitz (1973a, b) showed that C. rotundus, together with Sorghum halepense had more serious allelopathic effects than Cynodon dactylon on orange, cotton and mustard. Valliappan (1989) and Warner and Fox (1977) showed probable allelopathic effects on rice and banana respectively, while Meissner et al. (1979, 1982) demonstrated almost certain allelopathy against barley, cucumber, tomato and strawberry. Keeley (1987) provides a comprehensive review of the literature on these topics up to 1987.
The levels of loss caused by C. rotundus are not often satisfactorily separated from those caused by other weeds but by varying techniques, estimates have been obtained which occasionally show little or no loss, as in cassava, where populations up to 60 shoots/square m had no effect on root yields (Villamayor, 1983). Sierra and Mercado (1975) also showed no loss in transplanted tomato. More often very substantial losses have been recorded when the weed is allowed to compete for much or all of the growing season. Mangoesoekarjo (1977) compared a range of annual crops for their susceptibility to competition from C. rotundus and ranked them in the order upland rice (most susceptible), groundnut, maize and sorghum. In a similar study, Kondap et al. (1982) showed losses of 6% in maize, 12% in sorghum, 16% in cowpea, 22% in mung bean, 32% in groundnut and 58% in soyabean. Other studies emphasise the susceptibility of upland rice, losses recorded being 51% (de Datta, 1979), 41% (Okafor and de Datta, 1974) and over 40% (Sierra and Mercado, 1975). Particularly severe losses have also been recorded in squash, with over 90% yield reduction from a heavy population of nearly 900 shoots per square m (Ponchio et al., 1984) and in radish, with 100% yield loss from 125 shoots per square m at 100 kg N/ha or from only 75 per square m at 200 kg N/ha (Santos et al., 1998). In pepper, the loss was as high as 73% from 300 shoots per square m at 210 kg N/ha (Morales-Payan et al., 1998), though losses were much lower at lower densities of weed and at lower N levels (Morales-Payan et al., 1997). Other severe examples include 60% loss in onion (Tewari and Shukla, 1991). Cotton may be seriously affected (Sierra and Mercado, 1975). Cruz et al. (1969) recorded 30% loss in this crop and Saeed et al. (1977) a 14% yield loss from a population of about 600 shoots per square m. In the USA, Whitwell and Everest (1984) reviewed the results of a widespread survey in southern USA and concluded that C. rotundus was among the top 10 most troublesome weeds, infesting 460,000 ha of cotton across 15 states, but yield losses after normal weed control practices were probably modest. Losses in potato have been recorded as 25% (Tewari and Shukla, 1991), and in another study as only 3% (Tewari and Singh, 1991). In maize, results have likewise been varied with losses of only 14% (Tewari and Singh, 1991), while a study in Ghana showed that where C. rotundus was well controlled by prior glyphosate treatment, yields were almost doubled, corresponding to a 46% yield loss where it had not been controlled in spite of hand-weeding in the crop (Darkwa et al., 1999). In Brazil, studies in a range of irrigated vegetable crops showed losses from C. rotundus of 35% in cabbage, 39-50% in carrot, 41% in Phaseolus bean, 43% in cucumber, 62% in okra and 89% in garlic (William and Warren, 1975).
Perennial crops can also be seriously affected and in the study by Mangoesoekarjo (1977), cocoa was most susceptible followed by oil palm and rubber. Turner (1985) and Cerrizuela (1965) recorded 83% and 75% reductions in sugarcane yield respectively and Arevalo et al. (1974) also concluded that competition from C. rotundus for more than 30 days must be avoided if yields of sugarcane were not to be seriously affected. He recorded losses of approximately 15, 30 and 45% from infestations allowed to compete for 30, 45 and 90 days, respectively. Perez recorded 20% losses in pineapple (Perez, 1977). Nedunzhiyan (1995) notes that yields of taro can be 'drastically reduced' by C. rotundus. Holm et al. (1977) also refer to reductions in mulberry in Japan, citrus in Israel and coffee in Kenya.
Apart from direct effects on yield, Mangoesoekarjo (1977) notes how the rhizomes and tubers of C. rotundus can interfere with the harvest of groundnuts. Furthermore, Holm et al. (1977) quote estimates of the very substantial quantities of plant nutrients (and water) not only absorbed during the growing season, but locked away in the rhizome and tuber system for prolonged periods. In economic terms it can be conjectured that infestations of C. rotundus significantly raise the cost of manual weeding operations owing to the difficulty of removing the rhizomes and tubers, though quantification of these extra costs has not been seen.
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Is a habitat generalist
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Pioneering in disturbed areas
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Benefits from human association (i.e. it is a human commensal)
- Long lived
- Fast growing
- Has high reproductive potential
- Reproduces asexually
- Altered trophic level
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Infrastructure damage
- Modification of hydrology
- Modification of nutrient regime
- Modification of successional patterns
- Monoculture formation
- Negatively impacts agriculture
- Reduced native biodiversity
- Threat to/ loss of native species
- Damages animal/plant products
- Competition - monopolizing resources
- Competition - smothering
- Pest and disease transmission
- Rapid growth
- Highly likely to be transported internationally accidentally
- Highly likely to be transported internationally deliberately
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
- Difficult/costly to control
UsesTop of page
Parsons and Cuthbertson (1992) claim that C. rotundus is an important medicine in India and China and note its use by pharmaceutical companies to produce diuretics, anthelminthics and treatments for coughs, bronchial asthma and fever. It makes a poor fodder but has value in binding together soil. However, its negative attributes as a weed far outweigh its usefulness.
Uses ListTop of page
Animal feed, fodder, forage
- Fodder/animal feed
- Erosion control or dune stabilization
Human food and beverage
- Essential oils
Similarities to Other Species/ConditionsTop of page
In the vegetative stage, C. rotundus resembles several other sedge weeds but it can be distinguished by its wiry rhizomes (usually three per basal bulb) linking a network of tubers. By contrast, C. esculentus has numerous soft stolons bearing terminal tubers and annual species of Cyperus have no tubers or rhizomes. The purplish-brown inflorescence distinguishes C. rotundus from C. esculentus with its yellow inflorescence.
Prevention and ControlTop of page
Once established, C. rotundus can be such an intractable problem that preventative strategies should be employed to avoid its introduction and spread. Intensive use of the same weed management protocols, such as paraquat in coffee or triazine herbicides in maize, can promote the establishment of high populations of C. rotundus. Integrated control, such as crop rotations (Rambakudzibga, 1999) should be considered as part of the management strategy. Whatever methods are used, modelling the population dynamics of C. rotundus indicates that at least 95% control would be required to eliminate this weed (Neeser et al., 1998).
Successful cultivation depends on destroying the tubers of C. rotundus by exposing them to desiccation or by exhausting the food reserves. It is most effective on dry soils but it must be sustained to avoid re-establishment of the fragmented and dispersed rhizome/tuber network. This could necessitate cultivating every 2-3 weeks until the crop forms a canopy to suppress further growth of the weed. In practice this consumes much time and energy and could be detrimental to soil structure. Mowing 1-3 times a week reduces shoot and tuber populations on recreational turf grass (Summerlin et al., 2000).
Organic mulch made from crop residues, such as coir dust (Van Mele et al., 1996) provides temporary suppression of C. rotundus. A layer of 1000-gauge polyethylene is an effective barrier to growth that can be used in nurseries and high value field crops. Soil solarization by polyethylene cover sheets can control C. rotundus (Ricci et al., 1999). Higher soil temperatures and more effective control are possible with thermal-infrared-retentive (TIR) films than with a low-density polyethylene (LDPE) clear film (Chase et al., 1999). This treatment can have a negative effect on some soil biota.
Travolis et al. (2009) report that soil solarization seems potentially effective on C. rotundus tuber sprouting, as long as it resulted not only in a soil temperature shift, but also to a high diurnal temperature variation. Moreover, the uniform sprouting of about 95% of the tubers in the soil may allow for more complete control by mechanical, biological or chemical methods.
Few herbicides kill C. rotundus but several have been used to suppress growth until after crop establishment, including carbamate compounds such as EPTC, butylate, pebulate and vernolate, and the uracils bromacil and terbacil. Amitrole, 2,4-D, dichlobenil, MSMA, norflurazon and a range of other herbicides have all been used against C. rotundus but one of the most effective products is glyphosate (Terry, 1985). Applied post-emergence at the flowering stage, glyphosate is taken up by actively growing shoots and translocated to the tubers. Activity on the shoots is not observed until 2-4 weeks after treatment. Tuber populations can be reduced by 95% with multiple in-crop applications of glyphosate (Charles, 1997) or by single applications at the beginning of four consecutive seasons within 2 years (Darkwa et al., 1999). Glyphosate is inactivated on contact with the soil and has no effect on tubers that are not connected to emerged shoots.
It is questionable whether a cosmopolitan weed like C. rotundus with a huge regenerative capacity would be a good target for biological control but Evans (1991) claims that several fungi are promising candidates for classical biocontrol, including Puccinia conclusa, P. philippinensis and Phytophthora cyperi. Evans (1991) also notes that several pathogens are damaging to C. rotundus and warrant evaluation as possible mycoherbicides. The fungal pathogen, Dactylaria higginsii, has shown promise as a bioherbicide for the control of C. rotundus; three applications of 10 million conidia/ml gave >90% control (Kadir et al., 2000). Shabana et al. (2010) found that D. higginsii was more effective against C. rotundus than against Cyperus esculentus. The use of D. higginsii is reported by Yandoc et al. (2006) to be compatible with the use of some pesticides, although others reduced or inhibited conidial germination or mycelial growth.
The use of fungi for biological control of C. rotundus and C. esculentus is reviewed by Morales-Payan et al. (2005). The paper examines the biological enemies of nutsedges in nature (including vertebrates and arthropods), and the fungi associated with nutsedges and their potential for biological control (Balansia, Curvularia, Ascochyta, Puccinia, Cercospora and Dactylaria). Priyadharsini et al. (2013) suggest that metabolites produced by a Streptomyces strain inhibited sprouting of C. rotundus rhizomes.
Arthropod predators of C. rotundus that have been investigated as biological control agents include Athesapeuta cyperi, Chaetococcus australis, Bactra minima, B. venosana and B. verutana (Julien, 1992). Bactra spp. have been widely tested but natural enemies have restricted their impact.
ReferencesTop of page
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ContributorsTop of page
22/04/14 Updated by:
Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA
Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA
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