Cyperus rotundus L.

Code

CYPRO

Growth form

sedge

Biological cycle

vivacious

Habitat

terrestrial

Northern Cameroon: Cyperus rotundus grows all year if the soil is moist. In non-irrigated land, the emergence of young feet starts at the beginning of the rainy season and dramatically after each cultural operation (plowing, weeding). Flowering occurs 6-8 weeks after emergence.
Mayotte: Cyperus rotundus flowers and fruits all year round.

Cyperus rotundus likes sunny places and cannot stand shading and competition from species with high cover. It grows well in light soils and easy to penetrate. It is prevalent in damp areas but well drained.
 
Northern Cameroon: Cyperus rotundus grows in soils with pH between 5 and 7, with the exception of heavy clay soils. Its growth and rhizome network will be more important that the soil is light and easy to penetrate. This species requires moist soil but tolerates badly excess moisture. It is abundant in irrigated plots and frequent in patches, in the soil plots on ferruginous low area, provided that no water remains on the surface. It is also common in plots of sandy loam alluvial soils along river.
Comoros: This species grows in very well-lit open spaces especially in combination with Poaceae. It prefers damp, light soils. It is found in all parts of Grande Comore up to 600 m, up to 400 m in Anjouan and Moheli at low altitude.
French Guiana: It prefers sunny and humid areas. It forms chains of small spindle-shaped tubers at its rhizomes. Any type of tillage will lead to the multiplication of this species.
Mauritius: Species widespread throughout the island.
Mayotte: C. rotundus is quite rare in coastal areas, but is very common in sub-humid and secondarized environments, especially in crops, pastures, urban areas, gardens, where it can be very invasive.
New Caledonia: The species has been reported since 1850 and is the main weed in vegetable cultivations. It has remarkable plasticity. However environmental factors affect its development and the humidity is therefore essential for reproduction as well as for growth. Under certain conditions, it can therefore also become an invasive species of forage crops at planting or degraded. But she does not tolerate competition for light from other plants and tends to disappear when the vegetation grows. The tubers remain dormant in the soil until the next tillage.
Reunion: Extremely common species, it is present in the island on any type of soil and at any altitude.
Seychelles: Common species in all regions on almost all soil types, at all altitudes, but does not support shading.
West Indies: Cyperus rotundus grows rapidly on bare, light, regularly tilled soils. Poorly tolerant of interspecific competition, its abundance decreases on soils with a high floristic diversity.

Global harmfulness
 
Cyperus rotundus has the reputation of being the 'world's worst weed' and is the commonest and most troublesome Cyperus in most parts of East Africa. It occurs in all type of crop up to 2000 m (Ivens, 1989). It was also reported that C. rotundus is a persistent weed of cultivated fields and bush regrowths regarded as one of the world's most troublesome in West Africa (Akobundu et al., 1998). ). It is the most significant weed of 18 most malicious weed plant species of subtropical and tropical farming in both hemispheres and a weed of irrigated agriculture (cotton, maize, vegetable cultures, rice, sugar-cane, rarely lucerne and grain cultures), of gardens, kitchen-gardens, plantations of subtropical cultures.
Cyperus rotundus has spread throughout the warm, moist areas of the globe where it represents one of the 18 most harmful weeds of cropa.
 
Local harmfulness

Benin: frequent and generally abundant.
Burkina Faso: frequent and scarce.
Chad: rare and scarce.
Comoros: C. rotundus is a common weed of young crops of corn and rice. Its network of tubers makes it very difficult weeding.
Ivory Coast: common and generally abundant.
Ghana: frequent and generally abundant.
French Guiana: Very common in the non-flooded areas of the Mana rice polder. It is generally infrequent in the vegetable and fruit plots of French Guiana, but it can be occasionally very abundant in plots where tillage has favoured its multiplication.
Kenya: frequent and generally abundant.
Madagascar: locally very abundant species, which poses serious weed problems.
Mali:  rare but abundant when present.
Mauritius: very important weed of crops, which can have a very high harmfulness.
Mayotte: C. rotundus is a weed present in 4% of cultivated plots but can be locally abundant especially in plots of fruit trees, ylang-ylang.
Nigeria: frequent and generally abundant.
Uganda: common and generally abundant.
Reunion: C. rotundus is particularly well suited to the fields of young cane, maize and vegetable crops. This species is present in 50% of cultivated plots and appears as a bad major grass agriculture Reunion with a recovery rate regularly reaching 70-85%.
Senegal: frequent and generally abundant.
Seychelles: C. rotundus is considered a major weed in all crops, including cover crops, affecting the majority of vegetable and ornamental crops. It is very persistent when installed and difficult to control.
Tanzania: frequent and generally abundant.
West Indies: Cyperus rotundus is a species that is essentially frequent in sugar cane cultivation and in market garden and food crops, which it sometimes colonises in abundance. It is almost absent from banana plantations and fruit tree orchards because these crops offer unfavourable conditions (shade and floristic diversity).

Global control

Chemical control: As Cyperus esculentus, C. rotundus has the reputation of being the 'world's worst weed' and is the commonest and most troublesome Cyperus in most parts of East Africa. It occurs in all type of crop up to 2000 m (Ivens, 1989). It was also reported that C. rotundus is a persistent weed of cultivated fields and bush regrowths regarded as one of the world's most troublesome in West Africa (Akobundu et al., 1998). ). It is the most significant weed of 18 most malicious weed plant species of subtropical and tropical farming in both hemispheres and a weed of irrigated agriculture (cotton, maize, vegetable cultures, rice, sugar-cane, rarely lucerne and grain cultures), of gardens, kitchen-gardens, plantations of subtropical cultures. esculentus, C. rotundus is relatively sensitive to 2,4-D or MCPA at high doses. The tops of young plants are destroyed and regrowth may be delayed but the tubers themselves are unaffected. In young sugarcane, this level of control may retard weed growth long enough that culture can settle and make enough shade on later emergence. In most cultures, these effects are not durable enough. Among other chemicals of foliar absorption, high dose of glyphosate (preferably in a double application, first to 2000 g / ha and 1000 g / ha regrowth) is effective and can be used either before planting or as a directed spray. When its use was allowed, paraquat destroys the top of the plant, but it had to be applied several times to 4 weeks apart to achieve a lasting effect.
Biological control: In traditional rice-growing areas in India C. rotundus is controlled using pigs. Usually, the pigs are fed with vegetable waste and they look for tubers in wastelands. The pigs love these delicious and sweet potatoes. They can easily extract the tubers even if the soil is hard. Usually the field is watered and then the pigs are introduced on the plot. An animal may recover 2-4 kg of tubers per day and sixty animals can clean the tubers from 1 ha in one day.
Agronomic struggle cf. Document Mastering Cyperus rotundus by direct sowing in cotton cultivation in Brazil (click here)
Tips for weeding of perennial cyperaceae irrigated rice and lowland in Africa, visit: http://portal.wiktrop.org/document/show/30
 
 
Local control
 
Northern Cameroon: A 70% shading can reduce the production of C. rotundus tubers by 10-50%. It does not tolerate competition from other species such as Cynodon dactylon. In fallows, it disappears quickly, but the tubers can remain viable and latent in the soil for many years. Once the soil is plowed again and exposed, C. rotundus reappears. This species is not sensitive to pre-emergence herbicides. Adult plants are sensitive to systemic post-emergence herbicides but if they do not penetrate to the dormant tubers, they develop as soon as the plants affected by herbicide die.
 
New Caledonia: The best prevention in wetland pastures is to maintain a herbaceous cover, sufficient to hinder the germination and development of this heliophile. Once installed, C. rotundus is difficult to master. Tillage should avoid stimulating vegetative propagation. Plowing by rotary harrow, done in hot and dry weather, at the depth of the position of the bulbs would bring the dormant bulbs on the surface, leading to the depletion of underground reserves. This operation must be repeated every 6 weeks. Gyrobroyage is another common technique of maintenance provided that they can achieve sufficiently low cut. It is necessary to make several interventions for  defoliation to exhaust the plant. The use of an herbicide treatment is also possible (in total glyphosate and halosulfuron-methyl in Selective).
 
Madagascar: Tillage or pulling (very laborious) of fragment tuber chains, releasing progeny plant from the dominance of the mother plant, thus contributing to their rapid multiplication. Tolerant to most pre-emergence herbicides. Sensitive to 2,4-D and glyphosate, but in difficult application conditions on crops. It is best to control these weeds (glyphosate at 2160 g / ha) at the end of growing season to prepare for the following year. However, these cyperaceae does not support shade well. A good ground cover that delays (but does not stop) their emergence and a dense planting of a crop that quickly covers the ground allow to properly control them.
 
Mauritius: see recommendation sheets
 
MSIRI Sheet Recommendation No. 96 - Chemical Control of nut grass (click here)
MSIRI Sheet Recommendation No. 144 - Chemical Control of Weeds Tough  (click here)
 
Reunion:
Reunion: see the website of CaroCanne (The online magazine of sugar cane workers in Réunion);
Technical specifications No. 35

 

 Data acquired in Reunion on the effectiveness of herbicides in the sugarcane herbicide by eRcane Network with funding from the ODEADOM and ONEMA.

Action led by the French Ministry of Agriculture food and forest, with financial support from the National Agency for Water and Aquatic Environments, appropriations from the fee awarded to diffuse pollution Ecophyto finance the plan.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Cyperus%2520rotundus