Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Oryza punctata
(wild rice)



Oryza punctata (wild rice)


  • Last modified
  • 19 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Oryza punctata
  • Preferred Common Name
  • wild rice
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • O. punctata is locally quite important in some African countries but probably has a limited capacity to become invasive. It is listed as a noxious weed in the USA (

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Oryza punctata (wild or red rice); spikelets 5-6.2mm in length and 1.9-2.6 mm in width. USA.
CaptionOryza punctata (wild or red rice); spikelets 5-6.2mm in length and 1.9-2.6 mm in width. USA.
Oryza punctata (wild or red rice); spikelets 5-6.2mm in length and 1.9-2.6 mm in width. USA.
SpikeletsOryza punctata (wild or red rice); spikelets 5-6.2mm in length and 1.9-2.6 mm in width. USA.©USDA APHIS PPQ/USDA APHIS PPQ/ - CC BY 3.0 US
Rice and wild rice (O. punctata), Swaziland.
TitleOryza punctata (wild or red rice); habit.
CaptionRice and wild rice (O. punctata), Swaziland.
Copyright©Chris Parker/Bristol, UK
Rice and wild rice (O. punctata), Swaziland.
Oryza punctata (wild or red rice); habit.Rice and wild rice (O. punctata), Swaziland.©Chris Parker/Bristol, UK
Oryza punctata (wild or red rice); Keith Armstrong holding wild rice (O. punctata), Swaziland.
CaptionOryza punctata (wild or red rice); Keith Armstrong holding wild rice (O. punctata), Swaziland.
Copyright©Chris Parker/Bristol, UK
Oryza punctata (wild or red rice); Keith Armstrong holding wild rice (O. punctata), Swaziland.
HabitOryza punctata (wild or red rice); Keith Armstrong holding wild rice (O. punctata), Swaziland.©Chris Parker/Bristol, UK
Oryza punctata (wild or red rice); rice sample continaing grains of O. punctata and red rice.
TitleMixed rice grains
CaptionOryza punctata (wild or red rice); rice sample continaing grains of O. punctata and red rice.
Copyright©Chris Parker/Bristol, UK
Oryza punctata (wild or red rice); rice sample continaing grains of O. punctata and red rice.
Mixed rice grainsOryza punctata (wild or red rice); rice sample continaing grains of O. punctata and red rice.©Chris Parker/Bristol, UK


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Preferred Scientific Name

  • Oryza punctata Kotschy ex Steud.

Preferred Common Name

  • wild rice

Other Scientific Names

  • Oryza eichingeri var. longearistata Peter
  • Oryza sativa var. punctata (Kotschy ex Steud.) Kotschy & Schweinf.
  • Oryza sativa var. punctata (Kotschy ex. Steud.) Schweinf.
  • Oryza schweinfurthiana Prodehl

International Common Names

  • English: red rice
  • French: riz sauvage

Local Common Names

  • Germany: Reis, Wilder
  • Sudan: ruz el wadi

EPPO code

  • ORYPU (Oryza punctata)

Summary of Invasiveness

Top of page O. punctata is locally quite important in some African countries but probably has a limited capacity to become invasive. It is listed as a noxious weed in the USA (USDA-ARS, 2003).

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Poaceae
  •                             Genus: Oryza
  •                                 Species: Oryza punctata

Notes on Taxonomy and Nomenclature

Top of page Katayama (1995b) indicates high variablity in O. punctata from collections of 44 strains from Africa.


Top of page O. punctata is an erect or spreading, robust annual grass. Tufted, rarely stoloniferous. Rarely geniculate. Glabrous, smooth culms are up to 250 cm tall, usually over 4 mm, exceptionally up to 2.5 cm, in diameter at the base and have up to ten nodes. Leaf sheaths are pale-green to brownish, glabrous, nearly as long as internodes, with 15-mm-long auricles at the junction with the blade. The triangular, membranous ligule is less than 10 mm long. Bright to dark-green leaf blades are 10-75 cm long, 10-30 mm wide (20 times as long as wide), are broadest below the middle, triangulate, rough along the margins, otherwise smooth, glabrous with an indistinct mid-rib. Inflorescence a loose panicle 16-40 cm long which is composed of a few spreading branches, themselves up to 20 cm long. Panicle erect or slightly dropping with a tuft of hairs at the base of branches. Narrowly oblong, one-flowered spikelets up to 6.2 mm long, laterally compressed, always hairy and always pedicelled. Spikelets disarticulated above the glumes. Pedicels 7-15 mm long, scabrid to hispid and shed when mature. Glumes are only rudimentary. Sterile lemmas are 2-3.8 mm long, glabrous and smooth. Fertile lemmas are slightly shorter than the spikelet, stiffly hispid, with six stamens, a blackish stigma and a 2.6- to 7.5-cm-long awn, usually pink or purplish when fresh. The seeds are small, less than 5 mm long.

Plant Type

Top of page Annual
Grass / sedge
Seed propagated
Vegetatively propagated


Top of page O. punctata is mainly an African species (Ivens, 1989) distributed across southern, eastern, central and western Africa (Häfliger and Scholz, 1981).

Distribution Table

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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.


Top of page The Oryza genus is found in tropical and warm temperate regions, mainly in swamps (Heywood, 1978). O. punctata is chiefly a species of aquatic habitats (Häfliger and Scholz, 1981).

Habitat List

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Terrestrial – ManagedCultivated / agricultural land Present, no further details Harmful (pest or invasive)
Terrestrial ‑ Natural / Semi-naturalNatural forests Present, no further details
Natural grasslands Present, no further details
Riverbanks Present, no further details
Wetlands Present, no further details
Coastal areas Present, no further details

Hosts/Species Affected

Top of page O. punctata is a common weed of cultivated rice and has been recognized as a weed of cultivated dryland rice by Wirjahardja et al. (1983).

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Oryza sativa (rice)PoaceaeUnknown

Growth Stages

Top of page Seedling stage, Vegetative growing stage

Biology and Ecology

Top of page Genetics

There are two common genotypes of O. punctata, diploid 2n=24 and tetraploid 2n=48 (Watanabe et al., 1993). Lu et al. (1997) record the chromosome number in the tetraploid O. punctata as 2n=4x=48. Analysis of the distribution pattern of ploidy levels in Africa indicates that the diploid is widespread, the ranges of the diploids and tetraploids overlap (possibly with some degree of sympatry), and that tetraploids have spread beyond the range of diploids. Faluyi and Nwokeocha (1993) concluded from these data that the tetraploid is a young polyploid complex. Sano (1980) examined 22 characters in nine diploid (2n=24) and eight tetraploid (2n=48) strains of O. punctata. Among the 14 strains that were from known habitats, the diploids were from open grassland and the tetraploids from forests. Character differences were strongly correlated with ploidy. Compared with the tetraploids, the diploids showed high reproductive effort (seed weight as a percentage of total weight), well developed awns, low regenerating capacity of excised stem segments, short anthers and a high degree of dormancy.

Borromeo and Ramirez (1989) crossed an O. punctata accession to seven O. sativa lines and varieties. The F1 hybrids were all sterile due to abnormalities in chromosome number and behaviour. Hybrids, however, were better than either parent for height, flag leaf length and width, anther length, panicle length, spikelets/panicle and productive tillers/plant.

There has been much work concerning the hybridization of O. punctata, mainly with the aim of improving cultivated rice varieties.

Intergeneric hybrids resulting from the crosses O. punctata x Leersia tisserantii and O. punctata x L. perrieri were produced at frequencies ranging from 0.11 to 0.25% of the pollinated spikelets. The morphology of the hybrid plants strongly resembled the tetraploid Oryza species (Katayama, 1995a).

Reproductive Biology

Reproduction is by seeds; O. punctata rarely produces stolons. It is reported to remain dormant for up to 5 years (Armstrong, 1968).

Environmental Requirements

O. punctata grows in wet ground alongside streams and ponds from sea level to 1200 m (Ivens, 1989). At least some populations show some salt tolerance (Farooq et al., 1996), although Farooq et al. (1992) indicate much variability for salt tolerance in wild rice.

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
0 0 0 0


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ParameterLower limitUpper limitDescription
Mean annual rainfall00mm; lower/upper limits

Soil Tolerances

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Soil drainage

  • seasonally waterlogged

Special soil tolerances

  • saline

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Flowers/Inflorescences/Cones/Calyx seeds
Fruits (inc. pods) seeds
Growing medium accompanying plants seeds
Roots roots
Seedlings/Micropropagated plants whole plants
True seeds (inc. grain) seeds
Plant parts not known to carry the pest in trade/transport
Stems (above ground)/Shoots/Trunks/Branches

Impact Summary

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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


Top of page Both O. barthii and O. punctata are listed as economically important species which are a potential problem to US agriculture and which should therefore be kept out of the country by plant quarantine procedures (Reed, 1977; USDA-ARS, 2003).

O. punctata is a common weed of rice crops in East Africa (Terry, 1984). It has been noted as an important weed of rice paddies in southern Tanzania where populations can build up to problem levels after three years of cropping.

Risk and Impact Factors

Top of page Impact outcomes
  • Negatively impacts agriculture
Impact mechanisms
  • Competition - monopolizing resources
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally


Top of page O. punctata is used as food in times of famine in western Sudan (Salih and Nour, 1992).

Wild relatives of cultivated rice may be a useful source of genes for broadening the gene pool of cultivated rice, enhancing resistance to insect and pathogen attack (Khan et al., 1989).

Kaushal and Sidhu (1998) report that O. punctata is one of several species carrying resistant genes against the four most prevalent pathotypes of bacterial leaf blight (Xanthomonas oryzae pv. oryzae) under conditions in the Indian Punjab. Hybrids of O. punctata with O. sativa cultivars showed resistance to this bacterium, indicating that O. punctata is likely to carry the dominant gene for resistance (Kaushal, 1998). Zhang et al. (1994) reports that O. punctata showed resistance to bacterial leaf blight in trials carried out in China.

O. punctata collected from Nigeria showed 0% infection by Rice grassy stunt virus (RGSV-2) (Coloquio et al., 1998). Abo et al. (1998) indicate that O. punctata is also tolerant of Rice yellow mottle virus which threatens rice production in Africa. Kobayashi et al. (1991) reported high levels of resistance to Rice tungro spherical virus infection.

Velusamy (1988) reported resistance of wild Oryza species to the brown planthopper Nilaparvata lugens. In a free-choice seedbox screening test, Velusamy et al. (1995) found that wild rice species maintained their high resistance to N. lugens compared with cultivated varieties. O. punctata also showed high levels of antibiosis to the green leafhopper Nephotettix virescens (Kobayashi et al., 1991). Velusamy (1989) also reports resistance of wild rices, including O. punctata, to the whitebacked planthopper Sogatella furcifera. From greenhouse studies, Heinrichs et al. (1985) report resistance to Hydrellia philippina in O. punctata for which there is a lack of resistance in cultivated rice varieties (O. sativa).

Similarities to Other Species/Conditions

Top of page Aggarwal et al. (1999) indicate that there are 22 wild species of Oryza.

O. punctata is distinguished from O. longistaminata, the commonest of the weedy rices in Africa, by the absence of rhizomes.

The annual O. punctata is distinguished from O. barthii, a serious weed of rice in West Africa (Terry, 1983), by its small seeds (less than 5 mm long). The spikelets of O. punctata are up to 6.2 mm long and the length is approximately 2.5 times the width. In O. barthii the spikelets are somewhat larger, 7-11 mm long. The seeds of both these wild rices shed at maturity unlike those of the cultivated forms O. glaberrima and O. sativa.

Weedy shattering forms of O. sativa with a red pericarp or occasionally with black seeds have on rare occasions been introduced with planting seed into Africa, as occurred in Swaziland (Parker and Dean, 1976). These are sometimes referred to as O. rufipogon, although this is strictly a perennial species.

The "red rices" cause serious weed problems in the Americas (Holm et al., 1979). They lack rhizomes but, in common with O. longistaminata, have very long ligules (15-45 mm) on the lower leaves. Those of O. barthii and O. punctata are less than 10 mm long.

Prevention and Control

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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

Control of O. punctata in rice is facilitated by rotating the rice with broad-leaved crops in which control of grass weeds is easier. For example, in soyabeans, chemicals such as metolachlor can be used effectively as pre-emergence treatments (Ivens, 1989).

Parker and Dean (1976) state that annual wild rice problems are increased by dry sowing followed by flooding. For cultural control, soil puddling and direct sowing into water are recommended.

The more detailed suggestions for cultural control of O. rufipogon could well be applicable to this species.

Mechanical Control

Ghosh (1978) indicates that the highest yield of rice was obtained by hand-weeding three times in comparison to using selected herbicides for O. punctata control. The more detailed suggestions for mechanical control of O. rufipogon could well be applicable also to this species.

Chemical Control

1,8-Naphthalic anhydride, used as a seed dressing, has made it possible to control O. punctata in rice (Blair et al., 1976). Parker and Dean (1976) found that in a series of pot experiments with O. punctata and rice, 18 herbicides were at least partially selective and the selectivity could be greatly increased when the crop seed was dressed with 1,8-naphthalic anhydride. However, it is unlikely that 1,8-naphthalic anhydride is currently available or being used. While there is a lack of evidence for the use of newer herbicides on this species, it is probable that the treatments suggested for control of O. rufipogon could usefully be applied.


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Links to Websites

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GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.

Distribution Maps

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