Urena lobata L.

Mayotte : Urena lobata flowers from April to September and fruits from May to October.
New Caledonia: The growth cycle of Urena lobata is fast, the seeds germinate when it starts raining. The plant flowers as soon as the rainy season ends, to produce mature fruit in the cool season. The plant can reach 2 m before the end of the first year, the aerial part dies but new shoots grow from the root system.

Comoros: Urena lobata is a ruderal species, common on the three islands, especially at low and medium altitudes.
Madagascar: weed and ruderal plant, widespread throughout the island, up to 1200 m altitude. It infests rainfed crops, pastures, field edges and paths, on the highlands with ferrallitic soil slightly degraded, on tanety and baiboho (upland soils), especially in the Middle East. Its abundance is often indicative of compacted soils.
Mauritius: Native species, not very common.
Mayotte : Urena lobata is an exotic species very common in secondarized environments of mesophilic and hygrophilic regions. It develops in cultures, wastelands, pastures, villages, roadsides and sometimes even in natural forest.
New Caledonia: Urena lobata is said to be indigenous to New Caledonia, where it invades disturbed, eroded areas and some poorly managed or abandoned pastures. It has a great ecological plasticity and supports the altitude.
Reunion: Species infrequent, present along riverside.
Seychelles: Species present in clearings and abandoned plots.

Overall harmfulness
 
Urena lobata is considered invasive in some Pacific islands (Hawaii, Cook Islands, Samoa, Fiji, the Marquesas Islands, Guam, etc.) and Reunion.
It is considered a plague of crop and pasture due to its aggressiveness and the nuisance caused by its very adhesive fruits.
 
Local harmfulness
 
Burkina Faso: Rare and scarce.
Comoros: Species present in the abandoned wasteland. It may be found in all cultures.
Ivory Coast: Frequent and scarce.
Ghana: Rare and scarce.
Madagascar: important weed, common and abundant in the Middle West, the West and the Northwest, in rainfed rice crops, maize and cassava.
Mali: Rare and scarce.
Mauritius: This species is not present in crops.
Mayotte: Urena lobata is an uncommon weed, present in 7% of cultivated plots. It grows especially in pineapple plantations, but also in fruit, vegetable and food crops. It is present mainly in the south of the island.
New Caledonia: Urena lobata is native to New Caledonia where it invades disturbed eroded areas, and some poorly managed or abandoned pastures.
Uganda: Frequent and usually abundant.
Reunion: Species infrequent, not identified as a weed of crops or as an invasive species of natural environments.
Senegal: Frequent and scarce.
Seychelles: Not harmful.

Global control

Urena lobata is sensitive to oxadiazon applied at a dose of 750 to 1000 g/ ha in post-sowing/ pre-emergence rice. MCPA 400 g/ ha or 2,4-D applied for 25 or 30 days after sowing also gives good results.
 
For weeding Advice broadleaf perennial weeds in irrigated rice and lowland Africa visit: http://portal.wiktrop.org/document/show/25

Local control
 
Madagascar: manual control of Urena lobata can be done by weeding of the young plants or stripping of older plants. Chemically, it is controlled by 2, 4-D.
New Caledonia: Urena lobata is considered a secondary weed of Caledonian pastures due to limited presence, however, its aggressive nature makes it a potential plague of pasture to monitor. Maintaining a good cover of grass is enough to compete. It is essential to get rid of the stands that are installed and are likely to spread. Control methods are identical to those recommended for AIDS. Should avoid to graze cattle in infested areas during the period of fruiting. Herds coming from all of these plots should stay 4-5 days in quarantine plot.
Chemical control: Invaded areas can be rehabilitated by spraying of herbicide (2, 4-D) on regrowth of 2 weeks after slashing with rotary cutters at the beginning of the rainy season.

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