Click on images to enlarge
flower (Photo: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org)
plants in field (Photo: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org)
flower (Photo: Steve Dewey, Utah State University, Bugwood.org)
plant including roots (Photo: Steve Dewey, Utah State University, Bugwood.org)
Cynodon dactylon (L.) Pers.
Capriola dactylon (L.) Kuntze; C. aristiglumis Caro & Sanchez
Cynodon dactylon is very widely distributed throughout the world and its exact origin is unknown. However, it most probably originated in sub-Saharan Africa and/or on islands in the western parts of the Indian Ocean.
Cynodon dactylon is invasive in parts of Kenya and Tanzania and Uganda (Lyons and Miller 1999).
Most gardeners, if not most people, will know what Cynodon dactylon looks like, with its strong rhizomes and stolons and its flowering culms (flowering stems) which end in a whorl of 3-7 branches. C. dactylon occurs on almost all soil types especially in fertile soil, e.g. loamy soil. It is common in disturbed areas such as gardens, roadsides, overgrazed, trampled areas, uncultivated lands, localities with high levels of nitrogen, and is often found in moist sites along rivers. It is suitable for cultivation under dry land conditions.
Cynodon dactylon is a long-lived (perennial) grass, forming thick mats by means of stolons and rhizomes (horizontal, root-like stem usually found underground) (Gibbs Russell et al. 1991). The culms take root at the lower nodes. The leaf blade is flattened with a sharp tip, and is hairy or glabrous (hairless). The leaf sheath is round and glabrous; the ligule (membranous small structure at the junction of the leaf sheath and leaf blade) has ring of hairs or a short membrane. The inflorescence consists of 3-7 slender spikes up to 60 mm long, arranged terminally on the axis. The spikelets are sessile (stalkless) and without an awn (slender bristle-like structure). Flowering time is from March to September.
This species reproduces mainly by seed, which are known to germinate prolifically after fire. After fire, new shoots and leaves sprout quickly as they are nourished by ample underground reserves. It also sprouts profusely from root suckers, particularly when the roots are damaged. It is a very fast growing species. Animals such as white rhino, reedbuck, impala and many other wild animals graze it. As a result, these animals aid in the dispersal of this grass.
In eastern Africa there can be frequent confusion between Cynodon dactylon and Cynodon nlemfuensis. This species is similar to C. dactylon in almost all respects but it does not have below-ground rhizomes.
Cynodon dactylon can be used for erosion control. It is very easy to plant it in the garden as a lawn grass and even for farm pastures. While it does not produce much bulk, its feeding value is high and it grows fast. In traditional medicine it is used for indigestion and the treatment of wounds. However, it not recommended for planting as it is so difficult to eradicate. Its uses cannot compensate for this plant's overall negative impacts.
Holm et al. (1977) have categorised Cynodon dactylon as the second most important weed in the world (after nut-grass - Cyperus rotundus). C. dactylon can rapidly invade cultivated land, cause serious yield losses and it is extremely difficult to eradicate (Bogdan 1977). It can be toxic to livestock and is a host of pathogens and pests.
Cynodon dactylon has been included in the Global Invasive Species Database (GISD 2010).
The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species. Some components of an integrated management approach are introduced below.
The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.
Cover crops such as legumes are sometimes used to smother Cynodon dactylon as it does not tolerate deep shade. Traditional mechanical methods of control such as shallow hoeing are ineffective. But deep double ploughing to 60 cm can be effective. The effectiveness of chemical control seems to vary according to the clone (biotype). Possibilities for biological control using fungal pathogens are being investigated.
In Kenya Cynodon dactylon is declared a noxious weed of Agriculture under the Noxious Weeds Act CAP 325, in Kenya. Accordingly the Minister of Agriculture can compel land owners who have such declared noxious weeds growing on their land to eradicate or have it otherwise removed. However, it is not declared in Uganda and Tanzania.
Holm, L.G., Plucknett, D.L., Pancho, J.V. and Herberger, J.P. (1977). The World's Worst Weeds. Distribution and Biology. Honolulu, Hawaii, USA: University Press of Hawaii.
Lyons, E.E. and Miller, S.E. (eds) (1999). Invasive Species in Eastern Africa: Proceedings of a Workshop held at ICIPE, July 5-6, 1999.
Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.
This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).
BioNET-EAFRINET Regional Coordinator: [email protected]