Sida acuta Burm.f.

Code

Growth form

Biological cycle

Habitat

Mayotte : Sida acuta flowers and fruits all year round.
New Caledonia: The stem and leaves of Sida acuta may die in the dry season but its root remain alive (rooting depth is 0.6 to 1 m) to produce new stems in the rainy season. The seeds, extremely numerous (more than 3 million / ha), is dormant for 1-3 years and germinate rather early in the rainy season. The plant quickly established in the absence of competition and blooms during the rainy season. The fruits mature during the dry season. Seeds remain viable after ingestion and excretion.

Sida acuta prefers dry and sandy conditions, in upland crop areas, roadsides, waste places, and pastures. It can be found at higher elevation and grows well in many soils, including some heavy clay.

Comoros: Sida acuta is a ruderal species of low and medium altitude, between 0 and 800 m, present in fallow, rubble and on roadsides.
French Guiana: Erect or spreading sub-shrub, frequently found in ruderal areas and in orchards with permanent vegetation cover.
Madagascar: ruderal grass species and weed that grows in fallow or in rainfed cultures located around the villages especially at medium altitude (Middle East).
Mauritius: Uncommon Species on the island, it is an occasional weed of crop.
Mayotte: Sida acuta is an exotic species widely naturalized in secondarized environments of mesophilic and hygrophilic regions. It is found in crops, wastelands, pastures and in villages.
New Caledonia: Sida acuta is reported in New Caledonia since the 18th century (used to sweep the deck of ships, it has settled around the landing stages from the early days of colonization). It is widely spread on the territory at the edge roads, crops, overexploited pastures and degraded dry forests. A plant of light, from low to medium altitude (0 to 800 m), it prefers light to medium-heavy soils in humid to subhumid zones.
Reunion: This plant is found at low and medium altitudes between 0 and 1000 m, in abandoned places like ruins and roadsides and in cultivated land, mostly on the west coast of the island.
Seychelles: Common species.
 

Global harmfulness
 
Sida acuta is one of 300 major invasive species in tropical Australia, the Indian Ocean and Oceania including New Caledonia. This species is very woody and is very little consumed by livestock and deer
 
Local harmfulness
 
Benin: Rare but abundant when present.
Burkina Faso: Rare and scarce.
Comoros: Sida acuta is a weed present in cassava and banana plantations, very difficult to weed, it poses a lot of problems for farmers when clearing or preparation of the plots.
Ivory Coast: Frequent and scarce.
French Guiana: This species is infrequent and not very abundant in orchards in French Guiana, except when they are under permanent plant cover.
Madagascar: Species of medium frequency and generally scarce in crops. In some situations (case of the Middle West) it can be harmful to food crops that follows fallow or those located around the villages (maize, upland rice, cassava, groundnuts). In the Middle East, its frequency is high (57% of rainfed plots).
Mali: Frequent and scarce.
Mauritius: A weed with very low harmfulness, is rarely seen in cultures.
Mayotte: Sida acuta is a very infrequent weed (1% of cultivated plots), essentially found in food crops in the north of the island.
Nigeria: Rare and scarce.
New Caledonia: Reported since the 18th century (used to sweep the decks of ships, it has been grown around the docks in the early days of colonization). It is widespread in the territory along roadside, in crops, overexploit pastures and degraded dry forests. Plant of sunlight, low to medium altitude (0-800 m), it prefers light to moderately heavy soils in wetlands in sub-humid areas.
Reunion: uncommon weed in sugar cane and vegetable crops, never abundant.
Senegal: Rare and scarce.
Seychelles: A weed frequent but rarely abundant.
Tanzania: Rare and scarce.

Global control

Cultural control: Single plants or small patches of Sida acuta can be grubbed before flowering, taking care to cut the root well below the crown to minimize regrowth. In larger areas, satisfactory control is obtained by cultivation and sowing improved pastures.
Chemical control: 2,4-D at 0.5 to 0.8 kg ha-1 or MCPA at 0.4 kg ha-1 applied 20-30 days after emergence provides efficient control.
Biological control: Biological control for this species has been investigated in Australia. A leaf feeding chrysomelid beetle, Callingrapha pantherina, from Mexico was released in 1989.

Management recommandations for perennial broadleaf plants in rice fields: http://portal.wiktrop.org/document/show/26

Local control
 
Australia: Biological control of Sida acuta exists in Queensland with the use of an insect herbivore, introduced in Mexico in 1989, specific to the plant, the beetle Calligrapha pantherina which was also successfully introduced in Papua New Guinea.
Madagascar: Sida acuta is not harmful in general. Manual weeding is very difficult because of very powerful root system. Chemically, Sidas are controlled by atrazine, diuron or oxadiazon preemergence, and 2,4-D or glyphosate on young plants. Adult plants are relatively tolerant to these herbicides.
New Caledonia: Slashing with rotary cutters of overgrown areas just before flowering limits the spread of the seeds but do not destroy the stands. Avoid graze cattle in infested plots during the period of fruiting. Herds from these plots still have to stay in quarantine plot for 4-5 days. Chemical control: We can rehabilitate areas invaded by spraying herbide (2,4-D) on regrowth 2 weeks after gyrobroyage beginning of the rainy season. New sprouts must be eliminated by herbicide treatments directed, localized.
 
 

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