Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Cyperus iria
(rice flatsedge)

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Datasheet

Cyperus iria (rice flatsedge)

Summary

  • Last modified
  • 15 July 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Cyperus iria
  • Preferred Common Name
  • rice flatsedge
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae

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Pictures

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PictureTitleCaptionCopyright
Inflorescence simple or compound, usually open, 1-20 cm long and 1-20 cm wide, with groups of spikes either sessile or on 0.5-15.0-cm-long peduncles (rays).
TitleInflorescence of Cyperus iria
CaptionInflorescence simple or compound, usually open, 1-20 cm long and 1-20 cm wide, with groups of spikes either sessile or on 0.5-15.0-cm-long peduncles (rays).
CopyrightNOVARTIS
Inflorescence simple or compound, usually open, 1-20 cm long and 1-20 cm wide, with groups of spikes either sessile or on 0.5-15.0-cm-long peduncles (rays).
Inflorescence of Cyperus iriaInflorescence simple or compound, usually open, 1-20 cm long and 1-20 cm wide, with groups of spikes either sessile or on 0.5-15.0-cm-long peduncles (rays).NOVARTIS
Cyperus iria.
TitleCyperys iria
CaptionCyperus iria.
CopyrightR.K. Malik
Cyperus iria.
Cyperys iriaCyperus iria.R.K. Malik

Identity

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Preferred Scientific Name

  • Cyperus iria L. (1753)

Preferred Common Name

  • rice flatsedge

Other Scientific Names

  • Chlorocyperus iria (L.) Rikli (1895)

International Common Names

  • English: grasshopper's cyperus

Local Common Names

  • Bangladesh: barachucha
  • Brazil: tiririca-do-brejo
  • Cambodia: kak kangkep
  • India: morphula
  • Indonesia: dekeng wangin; djekeng; nyur-nyuran; rumput jekeng kunyit; umbung
  • Japan: kogomegeyatsuri
  • Korea, DPR: chambang-donsani
  • Malaysia: rumput menderong
  • Nepal: chow; guchen; mothey; ochumani
  • Pakistan: khana
  • Philippines: alinang; ballayang; payong-payong; sirau-sirau; sudsud; taga-taga
  • Thailand: kok huadaeng; yaa rangkaa khaao
  • USA: rice flatsedge

EPPO code

  • CYPIR (Cyperus iria)

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Cyperaceae
  •                             Genus: Cyperus
  •                                 Species: Cyperus iria

Notes on Taxonomy and Nomenclature

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C. iria was first described by Linnaeus (1753). It originated in the Old World tropics and subtropics and is one of approximately 650 species in the genus Cyperus (Haines and Lye, 1983). Courtoisia, Kyllinga, Mariscus and Pycreus are included in the genus Cyperus (Haines and Lye, 1983) though they are often cited as genera in their own right. Under the classification of Lye (1981), C. iria is in the subgenus Cyperus which contains about 300 species, including the common and important sedge weeds C. rotundus and C. esculentus.

Description

Top of page The height of C. iria plants varies from 8 to 60 cm. The roots are numerous, short and yellowish-red. The culms are tufted, triangular, glabrous, green and 0.6-3.0 mm thick. The leaves are linear-lanceolate, usually all shorter than the culm, 1-8 mm wide, flat, and scabrid on the margin and major ribs; leaf sheaths are green to reddish-brown, membraneous and envelope the culm at the base.

The inflorescence is simple or compound, usually open, 1-20 cm long and 1-20 cm wide, with groups of spikes which are either sessile or on 0.5-15.0 cm long peduncles (rays). Inflorescence bracts (involucre) are leafy, three to five (occasionally seven), the lower one longer than the inflorescence, 5-30 cm long, 1-6 mm wide. The spikes are sessile or almost so, elongate, and rather dense. Spikelets are erect-spreading, crowded, 6-24-flowered, 2-13 mm long, 1.5-2.0 mm wide, golden to yellowish-green.

Glumes are broad-ovate, 1.0-1.6 mm long, golden-brown. There are two or three stamens. The style is 3-branched. The fruit is a small achene (nutlet), 1.0-1.5 mm long, 0.6-0.7 mm wide, obovate, triangular in cross section, dark-brown to almost black; the surface is almost smooth. These descriptions are based on Haines and Lye (1983) and Holm et al. (1977).

Distribution

Top of page C. iria is most often found as a weed in Japan, the Pacific Islands and Australia to the south, and through India to the west. Outside Asia, it has been reported in southern and western Africa and in the USA (Holm et al., 1977). It has also been recorded in Kenya (Napper, 1966), Uganda (Haines and Lye, 1983; Napper, 1966) and Brazil (Lorenzi, 1982).

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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AfghanistanPresentHolm et al., 1979
BangladeshPresentMoody, 1989
BhutanPresentParker, 1992
Brunei DarussalamPresentWaterhouse, 1993
CambodiaPresentMoody, 1989
ChinaPresentWang, 1990
-GuangdongPresentWang, 1990
-HebeiPresentWang, 1990
-Hong KongPresentYip, 1976
-JiangsuPresentJiang et al., 1989
-ShaanxiPresentWang, 1990
-XinjiangPresentWang, 1990
-YunnanPresentWang, 1990
IndiaPresentPresent based on regional distribution.
-Andaman and Nicobar IslandsPresentSingh and Gangwar, 1986
-AssamPresentKurmi and Das, 1993
-HaryanaPresentMalik et al., 1981
-Himachal PradeshPresentBansal and Singh, 1986
-Indian PunjabPresentSidhu et al., 1982
-Jammu and KashmirPresentKaul, 1986
-KarnatakaWidespreadSastry et al., 1980
-KeralaPresentGeorge et al., 1990
-Madhya PradeshPresentSharma and Thakur, 1993
-ManipurPresentSingh and Singh, 1988
-MeghalayaPresentNeogi and Rao, 1982
-OdishaPresentJena and Patro, 1990
-Tamil NaduPresentKandasamy and Palaniappan, 1990
-Uttar PradeshPresentSingh and Singh, 1985
-West BengalPresentMukhopadhyay, 1982
IndonesiaPresentKostermans et al., 1987
JapanWidespreadNumata et al., 1975
-HonshuPresentNumata et al., 1975
-KyushuPresentNumata et al., 1975
-Ryukyu ArchipelagoPresentNumata et al., 1975
-ShikokuPresentNumata et al., 1975
Korea, Republic ofPresentPark and Kim, 1971
LaosPresentMoody, 1989
MalaysiaPresentBarnes and Chan, 1990
MyanmarPresentMoody, 1989
NepalPresentRanjit and Bhattarai, 1988
PakistanPresentMoody, 1989
PhilippinesWidespreadMoody et al., 1984
SingaporePresentWaterhouse, 1993
Sri LankaPresentWeerakoon and Gunewardena, 1983
TaiwanPresentAnon, 1968
ThailandPresentNoda et al., 1985
VietnamPresentMinh, 1969

Africa

Burkina FasoPresentClayton, 1972
GambiaPresentTerry, 1981
GhanaPresentClayton, 1972
KenyaPresentHaines and Lye, 1983
MaliPresentClayton, 1972
NigeriaPresentClayton, 1972
SenegalPresentClayton, 1972
SwazilandPresentHolm et al., 1979
TanzaniaPresentHaines and Lye, 1983
UgandaPresentHaines and Lye, 1983

North America

USAPresentHolm et al., 1979
-LouisianaPresentBaker and Shrefler, 1983
-MississippiPresentRiley et al., 1986

Central America and Caribbean

CubaPresentWazniak, 1976
Dominican RepublicPresentHolm et al., 1979
Puerto RicoPresentLiu and Lozano, 1987
Trinidad and TobagoPresentHolm et al., 1979

South America

BrazilPresentLorenzi, 1982
-AmazonasPresentLorenzi, 1982
-BahiaPresentLorenzi, 1982
-Espirito SantoPresentLorenzi, 1982
-GoiasPresentLorenzi, 1982
-MaranhaoPresentLorenzi, 1982
-Mato Grosso do SulPresentLorenzi, 1982
-Minas GeraisPresentLorenzi, 1982
-ParaPresentLorenzi, 1982
-ParanaPresentLorenzi, 1982
-PiauiPresentLorenzi, 1982
-Rio de JaneiroPresentLorenzi, 1982
-RondoniaPresentLorenzi, 1982
-Santa CatarinaPresentLorenzi, 1982
-Sao PauloPresentLorenzi, 1982
ColombiaPresentHäfliger et al., 1982
EcuadorPresentLopez et al., 1974
VenezuelaPresentHäfliger et al., 1982

Oceania

AustraliaPresentGroves, 1991
-QueenslandPresentGroves, 1991
FijiPresentHolm et al., 1979

Risk of Introduction

Top of page None known.

Habitat

Top of page C. iria is found in moist-to-wet soils, including river banks and ditches. It is an important weed of lowland and irrigated ricefields but is less important in the upland crop.

Hosts/Species Affected

Top of page C. iria is principally a weed of rice around the world but Holm et al. (1977) also noted its occurrence in bananas, cassava, groundnuts, maize, pastures, pineapples, sweet potatoes, tea and vegetables.

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Oryza sativa (rice)PoaceaeMain

Growth Stages

Top of page Vegetative growing stage

Biology and Ecology

Top of page C. iria is an annual sedge, sometimes behaving as a perennial. It propagates from seed (achenes or nutlets); a large plant can produce up to 5000 progeny (Holm et al., 1977). Forty percent of fresh seeds can germinate immediately and most dormant seeds can germinate only following a short period of after-ripening (Chozin and Nakagawa, 1988). Storage in darkness at low temperature, or in submerged soil, causes seeds to enter secondary dormancy. Light is required for optimum germination but germination in darkness, in upland soil, can be stimulated by alternating temperatures (20/35°C). Seeds of C. iria germinate at 15-40°C but an alternating temperature regime of 20/30°C is optimum. Seeds germinate well on the soil surface but few emerge from depths below 1 cm (Chozin and Nakagawa, 1988). C. iria is somewhat less able to germinate under water than C. difformis. Civico and Moody (1979) show that it may germinate under 1 cm of water but early development is suppressed at depths of 2.5 cm or more.

Chromosome numbers vary in C. iria (n=56, 64) and intraspecific variation in genotype and phenotype occurs (Bir et al., 1992). Natural hybridization can occur between C. iria and C. microiria (Chozin and Yasuda, 1991) to produce progeny of new-type plants of similar dormancy to the parents, showing clear segregation in spikelet characteristics and floret morphology. C. iria has Kranz-type leaf anatomy and, like C. rotundus, has two layers of bundle sheath cells (Lin et al., 1982). This is indicative of C4 photosynthesis which is generally not a characteristic of weeds growing in wet habitats.

Notes on Natural Enemies

Top of page Phoma cyperi sp. nov. is described from C. iria in India where it shows specificity towards nut sedges and produces at least one phytotoxin (Upadhyay et al., 1990). Cuscuta chinensis uses C. iria for mechanical support but, although haustoria are produced on the leaf lamina, there is no vascular contact between host and parasite (Mohanty and Rath, 1987). For pests and diseases of rice which also occur on C. iria, see Economic Impact.

Impact

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C. iria is rated by Holm et al. (1977) as one of the three most important weeds of rice in Sri Lanka, India and the Philippines. It is a principal weed in Indonesia and Japan and a common weed in Fiji, Thailand and the USA. It is principally a weed of rice around the world but Holm et al. (1977) also noted its occurrence in bananas, cassava, groundnuts, maize, pastures, pineapples, sweet potatoes, tea and vegetables. It is difficult to separate the competitive effects of C. iria from those of other components of the weed flora but the weed caused 40% yield reductions in rice (Ampong-Nyarko and DeDatta, 1991).

The costs of controlling C. iria, whether manual, mechanical or chemical, are significant. C. iria is a host for several pests of rice. In Cuba, it is a host of the rice nematodes Pratylenchus zeae and Hirschmanniella spinicaudata (Fernandez and Ortega, 1982). Criconemella onoensis is a rice nematode which uses C. iria as a host in the southern USA. Complete control of the weed is necessary before nematicides (e.g. fensulfothion) can be effective in increasing rice yields (Hollis, 1972).

Arthropod rice pests which use C. iria as a host plant include Scotinophara latiuscula (Barrion and Litsinger, 1987), Nisia atrovenosa (Cruz and Dela-Cruz, 1986), Lissorhoptrus brevirostris (Meneses-Carbonell and Carbonell, 1985), Nymphula depunctalis (Pillai and Nair, 1979), Baliothrips biformis and B. holorphnus (Ananthakrishnan and Kandasamy, 1977).

Pathogens of rice that have been reported on C. iria include Pyricularia oryzae [Magnaporthe grisea] (Singh and Singh, 1988), Rhizoctonia solani (Gokulapalan and Nair, 1983) and Acrocylindrium oryzae [Sarocladium oryzae] (Balakrishnan and Nair, 1981). Also the nematode Pratylenchus zeae (Waterhouse, 1994).

Uses List

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Medicinal, pharmaceutical

  • Traditional/folklore

Detection and Inspection

Top of page The experienced eye can detect seeds of C. iria as a contaminant of crop seed.

Similarities to Other Species/Conditions

Top of page C. iria is distinguished by its yellowish-red, fibrous roots; yellowish, usually open inflorescence; and by the lowest bract of the flower always being longer than the inflorescence (Holm et al., 1977). However, as a seedling or non-flowering plant, it closely resembles many immature, annual Cyperus spp. In a key to seedling Cyperaceae, Kostermans et al. (1987) use the coleoptile, seed, first leaf blade and first leaf sheath as diagnostic characters. It is sometimes possible to distinguish seedlings of C. iria from those of C. difformis by the mild aroma released when C. iria is crushed.

A very experienced eye is required to distinguish the seeds of C. iria from those of other Cyperus species.

Prevention and Control

Top of page Cultural Control

The principles of good weed management in rice, such as those advocated by Ampong-Nyarko and DeDatta (1992), are applicable to C. iria in rice and other crops. These include the need to prepare clean seedbeds, prevent seed production, establish a healthy and vigorous crop and avoid contamination of crop seed at harvest. C. iria is susceptible to many of the usual methods of weed control in rice and other crops. These include hand-pulling, manual and mechanical tillage and trampling in puddled fields. Flooding has a major suppressive effect during the early growth stages of C. iria (Civico and Moody, 1979) but established plants are difficult to control in this way and can tolerate 90 cm of floodwater for four days (Singh et al., 1983).

Biological Control

At present there are no biological control agents for C. iria but Phoma cyperi sp. nov., a pathogen of C. iria, may have some potential.

Chemical Control

A number of herbicides are approved for use in rice but their use is dictated by the conditions used to grow the crop, e.g. whether the crop is irrigated, rainfed lowland, upland and deepwater. C. iria is susceptible to the herbicides commonly used in rice: bensulfuron, bentazone, bifenox + 2,4-D, butachlor, butralin, 2,4-D, MCPA, molinate, oxadiazon, pendimethalin, piperophos + dimethametryn, pretilachlor + antidote (e.g. fenclorim), propanil, thiobencarb, thiobencarb + 2,4-D. Cinmethylin and fluorodifen were also active against C. iria (Ampong-Nyarko and DeDatta, 1991). Paraquat and glyphosate can both be used as non-selective, post-emergence herbicides against C. iria, for example in land preparation using zero-tillage.

Integrated Weed Management

Integrated weed management is recommended for cost-effective weed control; combinations of treatments such as: planting clean seed into a weed-free seedbed; sowing crop at optimum spacing; good water control; applying appropriate herbicides or cultivations; and harvesting crop grain which is not contaminated by weeds may be combined for an effective integrated control strategy.

References

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Ampong-Nyarko K; DeDatta SK, 1991. A Handbook for Weed Control in Rice. Manila, Philippines: International Rice Research Institute.

Ananthakrishnan TN; Kandasamy C, 1977. On the trends of infestation of two species of Baliothrips Uzel on paddy, maize and their weed hosts. Current Science, 46(10):344-345

Anon, 1968. Weeds found in Cultivated land in Taiwan, Volumes 1 & 2. Taipei, Taiwan: College of Agriculture, National Taiwan University.

Baker JB; Shrefler JW, unda. Rice weed control studies. 75th annual progress report, Rice Research Station, Crowley, Louisiana, 1983, 193-201

Balakrishnan B; Nair MC, 1981. Weed hosts of Acrocylindrium oryzae Saw., a sheath rot pathogen of rice. International Rice Research Newsletter, 6(6):13

Bansal GL; Singh CM, 1986. Germination, growth and development of some grass weeds under mid-hill conditions of Himachal Pradesh. Indian Journal of Weed Science, 17(3):53-55

Barnes DE; Chan LG, 1990. Common Weeds of Malaysia and their Control. Kuala Lumpur, Malaysia: Ancom Berhad Persiaran Selangor.

Barrion AT; Litsinger JA, 1987. The bionomics, karyology and chemical control of the node-feeding black bug, Scotinophara latiuscula Breddin (Hemiptera: Pentatomidae) in the Philippines. Journal of Plant Protection in the Tropics, 4(1):37-54

Bir SS; Chatha GS; Sidhu M, 1992. Intraspecific variation in Cyperaceae from Punjab Plain, India. Willdenowia, 22(1-2):133-142

Chozin MA; Nakagawa K, 1988. Autecological studies on Cyperus iria L. and C. microiria Steud., annual cyperaceous weeds. I. Seed dormancy, germination, and seedling emergence. Weed Research, Japan, 33(1):23-30

Chozin MA; Yasuda S, 1991. Possibility of natural hybridization between Cyperus iria L. and Cyperus microiria Steud. Weed Research (Tokyo), 36(3):282-289

Civico RSA; Moody K, 1979. The effect of the time and depth of submergence on growth and development of some weed species. Philippine Journal of Weed Science, 6:41-49

Clayton WD, 1972. Gramineae. In: Hutchinson J, Dalziel JM, Hepper FN, 1972. Flora of West Tropical Africa. Vol 3. Part 2. London, UK: Crown Agents, 349-512.

Cruz CG; Dela-Cruz CG, 1986. Host plant range of the planthopper Nisia atrovenosa. International Rice Research Newsletter, 11(2):26-27.

Fernandez M; Ortega J, 1982. Weeds as hosts of rice nematodes. Ciencias de la Agricultura, No.12:114-116

George S; Hameed SMS; Tajuddin E, 1990. Effect of resource constraints on weed growth in wetland rice. International Rice Research Newsletter, 15(1):36

Gokulapalan C; Nair MC, 1983. Collateral hosts of Rhizoctonia solani Kuhn causing sheath blight of rice. International Rice Research Newsletter, 8(6):10

Groves RH, 1991. Weeds of tropical Australia. Tropical grassy weeds., 189-196; 9 ref.

Haines RW; Lye KA, 1983. The Sedges and Rushes of East Africa. Nairobi, Kenya: East African Natural History Society.

Hollis JP, 1972. Nematicide-weed interaction in rice fields. Plant Disease Reporter, 56(5):420-424.

Holm LG; Pancho JV; Herberger JP; Plucknett DL, 1979. A geographical atlas of world weeds. New York, USA: John Wiley and Sons, 391 pp.

Holm LG; Plucknett DL; Pancho JV; Herberger JP, 1977. The World's Worst Weeds. Distribution and Biology. Honolulu, Hawaii, USA: University Press of Hawaii.

HSfliger E; Kühn U; HSmet-Ahti L; Cook CDK; Faden R; Speta F, 1982. Monocot Weeds 3. Basle, Switzerland: Documenta Ciba-Geigy.

Jena SN; Patro GK, 1990. Weed composition in dry seeded wetland rice. International Rice Research Newsletter, 15(3):34

Jiang RC; Xue G; Lou YL; Du JR, 1989. Field trials of oxyfluorfen, a herbicide used for control of weeds in rice field in Jiangsu Province. Jiangsu Agricultural Sciences, No. 5:22-24

Kandasamy OS; Palaniappan SP, 1990. Weeds in direct seeded ricefields of Thanjavur District, Tamil Nadu. International Rice Research Newsletter, 15(1):35

Kaul MK, 1986. Weed Flora of Kashmir Valley. Jodhpur, India: Scientific Publishers, 422 pp.

Kurmi K; Das GR, 1993. Effect of herbicides on weed control in transplanted rice. Integrated weed management for sustainable agriculture. Proceedings of an Indian Society of Weed Science International Symposium, Hisar, India, 18-20 November 1993 Hisar, Haryana, India; Indian Society of Weed Science, 3:27-29

Lin C-H; Hsue J-C; Tsay J-S, 1982. The anatomy of the noxious weeds on cultivated land of Taiwan. Proceedings of the National Science Council, Republic of China, B, 6(4):452-460

Linnaeus C, 1753. Species plantarum vol. I. Holmiae.

Liu LC; Lozano JJM, 1987. Bentazon mixtures to control weeds in rice. Journal of Agriculture of the University of Puerto Rico, 71(2):217-223

Lopez A; Salazar E; Veloz A, 1974. Behaviour of various herbicides for weed control in rice sown broadcast with pre-germinated seed. Asociacion Latinoamericana de Malezas "ALAM" [y] Sociedad Colombiana de Control de Malezas y Fisiologia Vegetal "COMALFI". Resumenes de los Trabajos en el II Congreso ALAM y VI Seminario, COMALFI, Cali, 1974., 50-51

Lorenzi H, 1982. Weeds of Brazil, terrestrial and aquatic, parasitic, poisonous and medicinal. (Plantas daninhas de Brasil, terrestres, aquaticas, parasitas, toxicas e medicinais.) Nova Odessa, Brazil: H. Lorenzi, 425 pp.

Lye KA, 1981. Studies in African Cyperaceae 18. Two new subgenera of Cyperus. Nordic Journal of Botany, 1:57-61.

Malik RK; Bhan VM; Katyal SK; Balyan RS; Singh BV, Weed management problems in rice-wheat cropping system adoption of weed control technology in north western India. Abstracts of papers, annual conference of Indian Society of Weed Science, 1981., 33

Meneses-Carbonell R; Carbonell RM, 1985. Rice water weevil host plants in Cuba. International Rice Research Newsletter, 10(1):21-22.

Minh Si H, 1969. Weeds in South Vietnam. Saigon, Vietnam: Agricultural Research Institute, Ministry of Land Reform and Development of Agriculture and Fisheries.

Mohanty SS; Rath GC, 1987. Infection of leaf lamina by Custuta chinensis Lamk. Indian Journal of Plant Pathology, 5(1):109-110

Moody K, 1989. Weeds reported in Rice in South and Southeast Asia. Manila, Philippines: International Rice Research Institute.

Moody K; Munroe CE; Lubigan RT; Paller EC Jr, 1984. Major Weeds of the Philippines. Los Baños, Philippines: Weed Science Society of the Philippines, University of the Philippines at Los Baños.

Mukhopadhyay SK, 1982. Noxious aquatic vegetation of West Bengal. Abstracts of papers, Annual Conference of Indian Society of Weed Science, December 27-30, 1982. Haryana, India: Indian Society of Weed Science.

Napper DM, 1966. Cyperaceae of East Africa - IV. Cyperus L. Journal of the East African Natural History Society, 26(1):1-24.

Neogi B; Rao RR, 1982. Weed flora of various hill agro-ecosystems in Meghalaya, north-eastern India. Australian Weeds, 2(1):9-15

Noda K; Teerawatsakul M; Prakongvongs C; Chaiwiratnukul L, 1985. Major Weeds in Thailand. Bangkok, Thailand: Department of Agriculture.

Numata M; Yoshizawa N, 1975. Weed flora of Japan. Japan Association for the Advancement of Phyto-Regulators. Tokyo, Japan: Zenkoku Noson Kyoiku Kyokai.

Park JK; Kim DS, 1971. Distribution of weeds and their competition with rice in Korea. Proceedings of the Asian-Pacific Weed Science Society Conference, 3.

Parker C, 1992. Weeds of Bhutan. Weeds of Bhutan., vi + 236 pp.

Pillai KS; Nair MRGK, 1979. Biology and habits of the rice case worm Nymphula depunctalis Guen. in Kerala. Entomon, 4(1):13-16

Ranjit JD; Bhattarai AN, 1988. Crop Weeds and their Control in Nepal. Kathmandu, Nepal: Winrock International/USAID.

Riley DG; Coats GE; Anderson DH, 1986. Evaluation of imazaquin and AC 263,499 for wild garlic control in turf. Proceedings, Southern Weed Science Society, 39th annual meeting, 112

Sastry KSK; Boraiah G; Govindu HC; Khaleel TF, 1980. Weeds of Karnataka. Weeds of Karnataka. University of Agricultural Sciences Bangalore India, 360pp.

Sharma RS; Thakur CL, 1993. Integrated and economically viable weed management in soybean (Glycine max)-wheat (Triticum aestivum) crop sequence. Indian Journal of Agricultural Sciences, 63(9):556-560

Sidhu M; Gogia BK; Kumar A, unda. Changes in weed flora of paddy fields of Patiala District (Punjab) during eleven years. Abstracts of papers, annual conference of Indian Society of Weed Science, 1982., 1

Singh G; Gangwar B, 1986. Weed management in dry season crops of Andamans. Seeds & Farms, 12(5):41-43

Singh NI; Singh KU, 1988. Unrecorded weed hosts for rice blast (BI) pathogen Pyricularia oryzae Cav. in India. International Rice Research Newsletter, 13(5):35

Singh RD; Sarkar PA; Ghosh AK, 1983. Tolerance of rice weeds for natural floodwater submergence. International Rice Research Newsletter, 8(5):19-20

Singh RK; Singh RP, 1985. Effect of water management practices on relative composition of weed flora in rice. Abstracts of papers, Annual Conference of Indian Society of Weed Science.

Soerjani M; Kostermans AJGH; Tjitrosoepomo G, 1987. Weeds of Indonesia. Jakarta, Indonesia: Balai Pustaka, 716 pp.

Terry PJ, 1981. Weeds and their control in the Gambia. Tropical Pest Management, 27(1):44-52.

Upadhyay RK; Strobel GA; Hess WM, 1990. Phoma cyperi sp.nov., a new pathogen of Cyperus iria, its vegetative and reproductive structures and production of phytotoxins. Canadian Journal of Botany, 68(10):2059-2064

Wang Z; Xin M; Ma D, 1990. Farmland Weeds in China. Agricultural Publishing House, 506 pp.

Waterhouse DF, 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR Monograph No. 21. Canberra, Australia: Australian Centre for International Agricultural Research, 141 pp.

Waterhouse DF, 1994. Biological Control of Weeds: Southeast Asian Prospects. Canberra, Australia: ACIAR Monograph No 26.

Weerakoon WL; Gunewardena SDIE, 1983. Rice field weed flora of Sri Lanka. Tropical Agriculturist, 139:1-14; 26 ref.

Wozniak H, 1976. Studies on the weed flora in important rice growing areas of the Republic of Cuba. Part I. The weed flora on the rice fields. Beitrage zur Tropischen Landwirtschaft und Veterinarmedizin, 14(4):349-359

Yip SM, 1976. A survey of the common weed species found in vegetable fields and weed control methods adopted by farmers in Hong Kong. Agriculture Hong Kong, 1(5):434-445

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