Solanum mauritianum Scop.

Mayotte: Solanum mauritianum flowers and fruits all year round.
New Caledonia: Solanum mauritianum is flowering and fruiting early in the rainy season.
 

Table of distintive characters of some Solanum species
 

Comoros: Solanum mauritianum is a species that has invaded the three islands. This is a common ruderal species in the wasteland and abandoned and degraded environments. It is present from low altitudes up to 1800 m.
Madagascar: weed and ruderal species very common in the East and in the highlands and in the wetlands of northern Madagascar. In the eastern regions, it infests rainfed crops on slash and burn ("tavy") and secondary areas ("savoka") to the edge of the rainforest. In the highlands, it is found around houses, on the edge of paths, roads and cultivated fields, located down slope or down slope of embankments, often fairly on fertile soil.
Mauritius: Common species in thickets and secondary vegetation in the upper parts of the island.
Mayotte: Solanum mauritianum is an exotic species very commonly naturalized in degraded, agricultural, grazed or urbanized areas. It is also sometimes found in natural vegetation in hygrophilic and mesophilic regions.
New Caledonia: Solanum mauritianum colonises firstly disturbed places. It is indifferent to altitude and tolerant to shade.
Reunion: very common invasive species in all vegetation in degraded situations up to 2000 m altitude. It is a pioneer species of sunny environments whose dissemination is largely ensured by fruit-eating birds. It colonizes the gullies, fallows with Acacia mearnsii and clear undergrowth and also edges of crops and badly maintained grasslands.
Seychelles: Absent.

Pest host: Solanum americanum is a host for the solanaceae fruit fly Neoceratitis cyanescens (Bezzi). Berries host fruit flies known to be important crop pests such as Ceratitis rosa Karsch and Ceratitis capitata (Wiedemann).
In South Africa, Solanum mauritianum is host to the KwaZulu-Natal fruit fly, an economic pest.

Toxicity

In Solanum mauritianum, the plant and especially the seeds contain nitrates and solanines, which could be responsible for neuromuscular disorders. Berries are toxic for human.

Global harmfulness
 
Solanum mauritianum is a weed of crops and badly maintained grasslands and invasive plant of gullies and degraded environments. This species is not consumed by livestock. It is one of the major invasive species in South Africa and Hawaii. Solanum mauritianum is among the 300 invasive plants in the Pacific-Indian Ocean region.

S. mauritianum is an aggressive invasive plant in the area of introduction which often takes the place of native species in secondary environments in the process of regeneration; it thus participates locally in the impoverishment of biodiversity. This pioneer species also colonises untended agricultural or forest areas, thus contributing to the closure of environments.
 
Local harmfulness
 
Australia: This shrub has recently become invasive in wet northern Queensland.Comoros: Solanum mauritianum is a pest for banana, cassava and vanilla cultivations.
Comoros: Solanum mauritianum is a harmful species for banana, cassava and vanilla plantations.
Fiji: Colonisation is more diffuse and mainly in coastal areas.
Hawaii: S. mauritianum is naturalized on slopes and edges of secondary rainforests.
Madagascar: It's a weed common and abundant in often poorly maintained slash and burn areas.
Mauritius: A weed of low to medium harmfulness in the sugar cane fields. This species is found in secondary vegetation, in pastures, in forest margins and in peri-urban areas. It is widely present but infestations are more important on the higher parts of the island.
New Caledonia: Reported for the first time in 1870, it is currently considered invasive in New Caledonia. Infestations are dense and localised in secondary forests; the spread in these environments is mainly along forest tracks which, when not maintained, end up being totally colonised by this species. It first colonizes disturbed sites. Its spread is favored by fires that cause mass germination and formation of dense groves covering the lower strata of vegetation. It is therefore present on the whole territory and can be very abundant in some pastures on forest tracks or on newly cleared land. It is relatively indifferent to the altitude and shade tolerant.
New Zealand: It is invasive in various regions, colonizing pastures, roadsides and semi-shaded areas.
Reunion: A common weed of crops. It is present in 25% of sugarcane plots but with a very low coverage, while in altitude meadow it is present in 55% of the plots with a covering rate up to 70%.  The species is found in secondary vegetation, in pastures, on forest edges and in peri-urban areas. 
Seychelles: Absent.
South Africa: Distributed to the Eastern part of South Africa including far southern part of South Africa. Declared as category 1, prohibited weed. It is an invasive weed. It is problematic in plantation, sugarcane fields and on wetlands. Invasions are most pronounced in the east of the country where rainfall is highest. The environments colonised are riverbanks, forest plantations, natural forests, agricultural land and all open and disturbed environments even in urban areas.
Tonga: Infestations are dense and occur in secondary forests and rubbish tips.

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