Rottboellia cochinchinensis (Lour.) Clayton

North Cameroon: Rottboellia cochinchinensis germination period begins in April with the first rains and lasts until late May. Any cultural operation (plowing, weeding, hilling) is followed by another period of germination. These new emergence can occur until September. Flowering begins in August but may be delayed until October in late emerged plants. Fruiting and dissemination take place from September to November until drying of the plant. In areas without a pronounced dry season, the species can develop at any time of year.

Rottboellia cochinchinensis is an annual species. It multiplies only by seeds that can remain viable in the soil for 2 to 3 years. The dissemination is done by water, agricultural tools, seeds of cultivated plants and animals. An individual can produce more than 3000 seeds.

Northern Cameroon: Rottboellia cochinchinensis is a nitrophilous species characteristic of silty clay and humid soil. It grows especially on alluvial soils along rivers, vertisols, the planosols in the shallows and on well-structured ferruginous soils.
French Guiana: Ruderal species which appreciates heavy and humid clay soils.
Comoros: species of medium to high altitude, as from 400 m. It is common in shaded to semi exposed areas.
Madagascar: Species widespread in all sub-humid and semi-arid low or medium altitude area of the Island (North West, West, Midwest and Southwest). It infests recent fallow and rainfed crops in the alluvial plains, depressions and lowlands where soils (vertisols, alluvial soils, ferruginous hydromorphic soils) are relatively rich.
Mauritius: Species present especially in the lower part of the island, it grows in abandoned fields and sugarcane fields.
Mayotte: Rottboellia cochinchinensis is an exotic species which grows during the rainy season on heavy and wet soils. It is particularly present in the center of the island.
Reunion: This plant is common in humid, sub-humid and warm. It appreciates the deep silty clay soil and very wet. It has now invaded all island areas below 1000 m, excluding the drylands.
Seychelles: Absent.
West Indies: Rottboellia cochinchinensis is an exotic species. It grows easily in untended areas and is particularly fond of clay soils in subhumid and humid areas.

Local harmfulness

Benin: Rottboellia cochinchinensis is rare, but abundant when present in paddy fields.
Burkina Faso: rare and scarce species in paddy fields.
Northern Cameroon: This species causes extensive damage to corn crops, especially cotton and upland rice. Its rapid growth allows it to seriously compete with crops early in the crop cycle. It is slightly sensitive to commonly used pre-emergence herbicides for weed control in cotton. The manual or mechanical weeding should be done early because when the stilt roots develop, the extraction becomes very difficult, especially as the stiff hairs of the base are wounding. This species can invade a plot in 2-5 years if its development is not adequately controlled by a specific herbicide and by early and repeated weeding. However, a good control of this species in 2 or 3 years provides an almost perfect eradication because the viability of seeds in the soil is low.
Chad: Rare and scarce in paddy fields.
Comoros: major weed of banana crops and fallow.
Ivory Coast: Frequent and usually abundant in paddy fields.
Ghana: Frequent and scarce in paddy fields.
French Guiana: An infrequent species and never abundant in orchards.
Kenya: Rare but abundant when present in paddy fields.
Madagascar: common species (43% of the plots in the Midwest and 60% in the South West) fast growing often forming a dense stand, it is especially harmful in growing cotton, maize and upland rice or peanut. Weeding is extremely difficult in rainy season or after a few days of delay because of its stiff wounding hairs and of its strong rootedness. It can quickly stifle crops thereby causing partial or total abandonment of heavily infested plots after delayed intervention.
Mali: Frequent and scarce in paddy fields.
Mauritius: A weed of low to medium harmfulness, hard to master.
Mayotte: Rottboellia cochinchinensis is an infrequent weed, present in 4% of cultivated plots. It is mainly present in fruit crops. It can be found in food crops.
Reunion: This species is present in 25% of the cultivated plots of the island. It is currently in the process of multiplying to the extent of forming real populations in sugarcane cultivation with high coverage of 30%. It also causes extensive damage to corn crops.
Senegal: Frequent and scarce in paddy fields.
Seychelles: Absent.
Tanzania: Frequent and usually abundant in paddy fields.
Uganda: Frequent and usually abundant in paddy fields.
West Indies: Rottboellia cochinchinensis is a very damaging weed present in all crops. If it is not controlled, it forms very damaging stands, particularly in sugarcane and young fruit crops. Under these conditions, each weeding operation can be followed by a germination.

Global control

For annual grass weed control tips FOR irrigated rice and lowland in Africa, visit: http://portal.wiktrop.org/document/show/32 

Local control

Madagascar: Tillage triggers germination of Rottboellia cochinchinensis. Pulling or weeding should be done very early, before the development of the root system makes them difficult.
Pre-clearance, pendimethalin (or oxadiazon) are very interesting in infested plots. In post-emergence, the young roettboellia is susceptible to fluazifop-p-butyl. Glyphosate alone destroys the old seedlings.
Able to grow through mulching. A very thick blanket of stylosanthes however enables its control and elimination over few years.

 La Réunion : see the site of  CaroCanne (online magasine for the experts in sugarcane in Reunionn) ; cahier technique n°34

(Doses are expressed in commercial products) - 2014

Data acquired in Reunion on the effectiveness of herbicides in the context of the sugarcane herbicide network 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, on the finance issued from the tax for the pollution diffused, attributed to the finance of the Ecophyto plan.

West Indies: Good control of Rottboellia cochinchinensis requires the use of a pre- or post-emergence herbicide when it has 4 to 5 leaves.

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