Cyperus iria L. (Rice Flatsedge)

Course name: Weed Science and Biology

Student name: Rivandi Pranandita Putra

University: University of Goettingen, Germany

Date: 05-February-2015

 

1. ABOUT THIS WEED

Cyperus iria is a tufted annual sedge native to Eurasia (Holm et al., 1977), with red fibrous roots and a long lower bract

1.1. Identity Names

Preferred Scientific Name : Cyperus iria L. (1753)

Preferred Common Name: rice flatsedge

Other Scientific Names: Chlorocyperus iria (L.) Rikli (1895)

International Common Names: Grasshopper’s cyperus (English)

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)

1.2. Taxonomy

Domain: Eukaryota

Kingdom: Plantae

Phylum: Spermatophyta

Subphylum: Angiospermae

Class: Monocotyledonae

Order: Cyperales

Family: Cyperaceae

Genus: Cyperus

Species: Cyperus iria

2. MORPHOLOGY

Generally, it is smooth, tufted, annual sedge that grows to 60 cm. Stems: Sharply triangular in crosssection, occurring in bunches.

Leaves: Dark green, shiny, linear in outline but tapering to a point, and three-ranked. Leaves have rough margins toward the leaf tips. Leaves have sheaths enveloping the stem at the base, membranous, with blade linear, lanceolate, shorter than the flowering stem, about 5 mm wide.

Flowers: Terminal seedheads occur at the ends of the triangular stems. Seedheads may reach 20 cm in length, are open, and are composed of several dense spikes. Individual spikes are, in turn, made up of many Yellowish brown spikelets. Seedheads also have 3 to 7 unequal bracts surrounding the inflorescence, the lower one being much longer than the overall inflorescence.

Fruit: a three-angled brown achene. The fruit has a yellowish brown achene, obovate, triangular in cross section, 1 to 1.5 mm long.

Roots: Yellowish red fibrous root system.

The inflorescence is a compound umbel, with primary rays about 10 cm long, secondary rays about 2 cm long, subtended by 3 to 5 (occasionally 7) bracts.

3. HABITAT AND DISTRIBUTION AREAS

Cyperus iria grows well in moist to wet soil in annual and plantation crops. It is one of the most common weed in rice fields and other flooded crops. It is found nearly everywhere in irrigated rice fields. It is mainly a weed of open, wet place (Holm et al., 1977).

Cyperus 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).

Geographical distribution of the weed is in:

• Asia: China (including Taiwan), Japan, and Korea.
• South and Southeast Asia: Bangladesh, Cambodia, India, Indonesia, Lao PDR, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam.
• Rest of the world: Australia, Fiji, Swaziland, West Africa.

4. REPRODUCTION

This weed is propagated by seeds, which may be dormant but can germinate about 75 days after shedding. It is a prolific seed producer and spreads quickly. One weed may produce around 3000 to 5000 seeds. The prodigious rate of multiplication of Cyperus iria is due partly to the profusion of seeds and partly to its short life cycle. The seedlings appear soon after rice is sown, the flowers appear in about one month, shed their seeds, and may establish a second generation in the same season.

5. AGRICULTURAL IMPACT

Cyperus 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 Cyperus iria from those of other components of the weed flora but the weed caused 40% yield reductions in rice (Ampong-Nyarko and DeDatta, 1991)

6. CONTROL MANAGEMENT

Control management of Cyperus iria could be done by some ways, such as:

6.1. Cultural control

Cultural control can done by hand weeding at earlier stage of growth to prevent flowering and seed production; rotary weeding in transplanted rice during the seedling stage. The principles of good weed management in rice, such as those advocated by Ampong-Nyarko and DeDatta (1992), are applicable to Cyperus 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. Cyperus 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 Cyperus 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).

6.2. Biological control

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

6.3. Chemical control

Butachlor or oxadiazon after harrowing and sowing of rice and chlorimuron, propanil, or MCPA after emergence.

6.4. Integrated Weed Management (IWM)

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.

7. RELATIONS BETWEEN THE WEED TO PESTS AND DISEASES

Cyperus iria is sometimes known as 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 Cyperus 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 Cyperus 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 Baliothrips holorphnus (Ananthakrishnan and Kandasamy, 1977).

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

 

References

Galinato MI, Moody K, Piggin CM. 1999. Upland rice weeds of South and Southeast Asia.     Manila (Philippines): International Rice Research Institute. 156 p.

Gokulapalan C, Nair MC. 1983. Collateral hosts of Rhizoctonia solani Kuhn causing   sheath blight of rice. Int. Rice Res. Newsl. 8:10.

Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. 1977. The World’s Worst         Weeds: Distribution and Biology. East-West Center/ University Press of Hawai

Kern JH. 1974. Cyperaceae. Flora Malesiana Ser. 1 7(3): 435-753.

Merrill ED. 1976. A flora of Manila. Manila (Philippines): Department of the Interior,         Bureau of Science. 491 p.

Moody K. 1989. Weeds reported in rice in South and Southeast Asia. Manila  (Philippines): International Rice Research Institute. 442 p.

Pancho JV, Obien SR. 1995. Manual of ricefield weeds in the Philippines. Muñoz, Nueva     Ecija (Philippines): Philippine Rice Research Institute. 543 p.

Venkitesan TS, Satyakumar Charles J. 1979. The rice root nematode in lowland paddies      in Kerala, India. Int. Rice Res. Newsl. 4:21.