Cynodon dactylon (L.) Pers. - POACEAE - Monocotyledon

Basionym : Panicum dactylon L.

Synonym : Cynodon arcuatus C. Presl, C.parviglumis Ohwi

Common name : Bermuda grass, couch grass.

English Français Khmer Lao

Botany Biology Phenology Ecology Distribution Agricultural importance Cultural control Chemical control

Botany :

Description :

Terrestrial, annual or perennial, tufted herb, not rooting at nodes. Roots fibrous, white or brown. Stems rounded, hollow or solid, glabrous. Nodes glabrous. Stipules absent. Leaves simple, alternate distichous, sessile, linear, more than 2 cm long/wide, margin entire, apex acute, base clasping, parallel-veined. Leaf sheath present. Ligule membranous hairy, a conspicuous ring of white short and long hairs. Flowers bisexual, grouped together in a terminal, digitate raceme, sessile, green, petals not visible. Fruit a nut.

Couch grass is a perennial herb that reproduces mainly vegetatively, eventually by seeds. It produces few seeds and they can survive submerged up to 50 days; seeds can germinate throughout the year if moisture supply is adequate. It propagates rarely by seeds, but mostly by cutting, by sprouts and by stolons and rhizomes growing deeply in the soil.

Phenology :

Flowering and fruiting throughout the year.

Ecology :

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.

Distribution :

Pan- tropical and subtropical, and some temperate areas.

Agricultural importance :

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 control :

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 control :

Use of glyphosate application under non cropped area effectively controls C. dactylon in upland rice.

Remarks :
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.

References :
-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