Common name : Bermuda grass, couch grass, kwwek
Common name in Bengali : Doorba, dubla, durba, durbaghas
Common name in Hindi : Dub, hariyali
Common name in Urdu : Khabbal, talla ghas
Bangla English Hindi Urdu
Diagnostic characters
Biology
Ecology and distribution
Nuisance
Weed control
Botany
Uses/Remark
References
Cynodon dactylon is a prostrate mat-forming grass and my be the most serious weed of the grass family.The stems is very ramified, spreading at the soil surface by long rhizomes and stolons.The leaves are narrow and with flat arrangement. The nodes and leaf sheaths are glabrous.The erect inflorescence has 3 to 7 spikes in a single terminal whorl, arranged like the fingers in a hand.
Couch grass is a perennial herb. It produces few seeds and they can survive submerged up to 50 days; seeds can germinate throughout the year if moisture supply is adecuate. It propagates rarely by seeds, but mostly by cutting, by sprouts and by stolons and rhizomes growing deeply in the soil.
This weed is native of tropical Africa or the Indo-Malaysian area and India. Now grows widely throughout tropical, subtropical and temperate areas of the world. It may grow in different biotopes. Common in upland rice, moist but not flooded soils, particularly in areas regularly disturbed. This species is adapted to a wide range of soils with a preference for the sandy, muddy and well drained ones.
C. dactylon is a troublesome weed of agriculture worldwide, reported to occur in more than 80 countries and in some 40 different crops such as rice, sugarcane, maize, vineyards and plantation crops. The rhizomes can be shallow or as deep as 1 m or more. This makes it successful and persistent weed under a wide range of conditions. A single bud of a rhizome or rhizome piece can develop into a shoot. In Bangladesh it can reduce rice yield by 50%.
- Cultural
Seedlings can be destroyed by cultivation but perennating organs are difficult to eradicate. The plants with creeping stolons on the soil surface can be controlled by frequent shallow cultivation and removing the weed to prevent re-rooting. Rhizomatous ones are more difficult to control. Several dry-season cultivations can be effective if the rhizomes are brought to the surface, where they are killed by desiccation. This usually requires tractor-drawn implements, especially where deep rhizomes are present.
- Chemical
Use of glyphosate application under non cropped area effectively controls C. dactylon in upland rice.
Habit
Perennial herb that spread by strong, flat stolons and scaly rhizomes to form a dense turf on the surface of the soil but also a strong ramified system underground.
Roots
Fasciculated growing from nodes in the rhizomes and stolons. Stem
The culm is erect or trailing on the ground, cylindrical, hollow, green to reddish and glabrous, 1 to 3mm large and 10 to 60cm tall, rarely more than 1 m. Numerous fertile culms; nodes dark and glabrous.
Leaves
Leaf blades with a distichously disposition; linear, smooth and glabrous, apex abruptly rounded, margin scabrous to the apex; 2 to 6mm large, 1 to 20cm long. Leaf sheaths up to 15mm long, shorter than internodes, smooth; carina rounded pubescent to glabrous. Ligule membranous hairy, a conspicuous ring of white short and long hairs.
Inflorescence
Three to seven spikes, sometimes purplish, in one whorl, in a fingerlike arrangement (digitately), 3 to 10cm long. Spikelets 2 to 3mm long, sessile, with a single floret, alternate, laterally flat, in two rows tightly appressed to one side of the rachis. Glumes purplish. Lemma boat-shaped, acute with fringe of hairs on the keel, longuer than the glume, with pubescent margin to the apex.
Fruit
Caryopsis ellipsoid, laterally compressed, 1.5mm long, oval, straw-colored to orange-red, free within the lemma and palea.
Seedling
The seedling at the second leaf stage, present a short ligule membranous-hairy and some hairs on the lamina. The lamina is linear with a margin lightly scabrous.
The distinguishing characteristics of this species are the ligule, which is a conspicuous ring of white hairs; the lemma, which has a fringe of hairs on its keel; and the often gray-green color of the foliage.
- Le Bourgeois T., Jeuffrault E., Grard P., Carrara A. 2001. AdvenRun V.1.0. Les principales mauvaises herbes de La Réunion. CD-ROM. Cirad, SPV. France.
- Galinato M., Moody K., Piggin C. M. 1999. Upland rice weeds of South and Southeast Asia. IRRI. Philippines.
- Holm L. G., Plucknett D. L., Pancho J. V., Herberger J. P. 1991. The world’s worst weeds. Distribution and Biology. East-West Center by the University Press. Hawaii.
- Merlier H., Montégut J. 1982. Adventices Tropicales. Flore aux stades plantule et adulte de 123 espèces africaines ou pantropicales. Orstom, Cirad-Gerdat, Ensh. Montpellier, France.
-Bari, M. N. 1997. Major rice weeds in Bangladesh. Department of Agronomy. BSMR Agricultural University, Gazipur, Bangladesh.
Top of the page