Solanum mauritianum Scop., Solanaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 24 (Go to the risk assessment).

Other Latin names:  Solanum auriculatum Ait.; Solanum verbascifolium L. var. auriculatum (Ait.) Ktze.

Common name(s): [more details]

English: bugweed, tree tobacco, wild tobacco, woolly nightshade

French: bringelier marron, faux tubac, tabac marron

Hawaiian: pua nānā honua

Maori (Cook Islands): ‘ava‘ava, rau ‘ava‘ava

Tongan: pula, to‘uloku

Habit:  shrub

Description:  "Shrubs or small trees 2-4 m tall, branched above to form a rounded canopy, unarmed, all parts densely pubescent with sessile to long-stalked stellate hairs, loose and floccose on young growth.  Leaves paler on lower surface, simple, alternate, elliptic, up to 30 cm long and 12 cm wide on young vigorous growth, usually ca 18 cm long and ca 7 cm wide, on mature stems margins entire, apex acuminate, base cuneate, often oblique, petioles 3-9 cm long, each with 1-2 smaller auriculate leaves in axils, these sessile, rounded, sometime absent from weak or distal shoots.  Flowers perfect, actinomorphic, numerous in branched corymbs, peduncles up to 15 cm long to first fork, pedicels 2-3 mm long; calyx tube short, 2-3 mm long, the lobes narrowly triangular, 2-3 mm long; corolla lilac blue with a pale star-shaped area at base, stellate, 1.5-2.5 cm in diameter; stamens 5, inserted low on corolla tube; filaments ca 1 mm long; anthers oblong, 2-3.5 mm long, opening by terminal pores; ovary densely pubescent; style pubescent in lower part, 5-7 mm long; stigma green, terminal. Berries dull yellowish, succulent, globose, 1-1.5 cm in diameter, pubescent at least in early stages.  Seeds numerous, flattened, 1.5-2 mm long, testa minutely reticulate.  Self-compatible" (Wagner et al., 1999; pp. 1271, 1273).

Habitat/ecology:  "Grass- and heathland, riparian habitats, wet forests, coastal beaches.  This shade tolerant shrub grows to dense thickets shading out all other vegetation.  It primarily colonizes disturbed sites and its spread is  promoted by fire.  Seed germination is enhanced after fire, and firres often lead to mass germination, resulting in a dense cover of seedlings"  (Weber, 2003; p. 406).

In Hawai‘i, "naturalized on slopes and ridges in disturbed wet forest" (Wagner et al., 1999; pp. 1271, 1273).  In Fiji, "sparingly naturalized near sea level"  (Smith, 1991; p. 9). In Tonga, "in thickets and open second-growth forests and waste areas" (Yuncker, 1959; pp. 238-239). In New Caledonia, "localement abondant, notamment sur pistes forestières abandonnées" (MacKee, 1994; p. 132).

Propagation:  "Seeds are dispersed by birds.  The shrub resprouts prlifically frum the base and trunk if damaged"  (Weber, 2003; p. 406).

Native range:  Uruguay and southeastern Brazil (Smith, 1991; p. 9).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced	Pickard, J. (1984) (p. 208)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 21) "A frequent and serious weed". Vouchers cited: J. Pickard s.n. (NSW), J. Pickard in A.N. Rodd 1401 (NSW), J. Pickard 2948 (NSW)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Ziesing, P. (1997) (pp. 34-35)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 11) "A frequent and serious weed". Vouchers cited: G. Uhe 1107 (K), W.G. Milne 5 (K)
Cook Islands Southern Cook Islands	Aitutaki Atoll	introduced invasive	Space, James C./Flynn, Tim (2002) (p. 77) Voucher: Flynn 7104 (PTBG, BISH, US)
Cook Islands Southern Cook Islands	Aitutaki Atoll		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2002) (voucher ID: PTBG 398) Taxon name on voucher: Solanum mauritianum
Cook Islands Southern Cook Islands	Rarotonga Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 89)
Cook Islands Southern Cook Islands	Rarotonga Island		McCormack, Gerald (2013)
Cook Islands Southern Cook Islands	Rarotonga Island		Bishop Museum (Honolulu) (1929) (voucher ID: BISH 181813) Taxon name on voucher: Solanum mauritianum Scop.
Cook Islands Southern Cook Islands	Rarotonga Island		Bishop Museum (Honolulu) (1929) (voucher ID: BISH 181814) Taxon name on voucher: Solanum mauritianum Scop.
Cook Islands Southern Cook Islands	Rarotonga Island		Bishop Museum (Honolulu) (1977) (voucher ID: BISH 420151) Taxon name on voucher: Solanum mauritianum Scop.
Cook Islands Southern Cook Islands	Rarotonga Island		Bishop Museum (Honolulu) (1991) (voucher ID: BISH 665157) Taxon name on voucher: Solanum mauritianum Scop.
Fiji Fiji Islands	Fiji Islands	introduced invasive	Smith, Albert C. (1991) (p. 9) Voucher cited: DA 13938
French Polynesia French Polynesia Islands	French Polynesia Islands		Waterhouse, D. F. (1997) (p. 65)
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1271, 1273) Voucher cited: Rock 1132 (NSW)
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Meyer, Jean-Yves (2000) (p. 100) "Forestry trails, edges"
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 383) Localement abondante, notamment sur pistes forestières abandonnées.
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	MacKee, H. S. (1994) (p. 132) Vouchers cited: Pancher s.n., Le Rat 414, Däniker 1851, Virot 1085, Sarlin 262, MacKee 20649
New Caledonia New Caledonia Archipelago	Île Grande Terre		Bishop Museum (Honolulu) (1968) (voucher ID: BISH 401971) Taxon name on voucher: Solanum auriculatum
Solomon Islands Solomon Islands	Solomon Islands	introduced invasive	Shine, C./Reaser, J. K./Gutierrez, A. T., eds. (2003) (p. 166) Dominant invader.
Tonga Ha‘apai Group	Nomuka Island	introduced invasive	Yuncker, T. G. (1959) (pp. 238-239) Voucher cited: Yuncker 15818
Tonga Ha‘apai Group	Nomuka Island		Bishop Museum (Honolulu) (1953) (voucher ID: BISH 181875) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tonga Islands	Tonga Islands	introduced invasive	Yuncker, T. G. (1959) (pp. 238-239) "Throughout Tonga".
Tonga Tongatapu Group	‘Eua Island	introduced invasive	Space, James C./Flynn, Tim (2001) (p. 9)
Tonga Tongatapu Group	‘Eua Island		Whistler, W. A. (1992) (p. 74) Voucher cited: Parks 16086
Tonga Tongatapu Group	‘Eua Island	introduced invasive	Yuncker, T. G. (1959) (pp. 238-239) Vouchers cited: Parks 16086, Yuncker 15325
Tonga Tongatapu Group	‘Eua Island		Bishop Museum (Honolulu) (1926) (voucher ID: BISH 181874) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tongatapu Group	‘Eua Island		Bishop Museum (Honolulu) (1953) (voucher ID: BISH 181876) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tongatapu Group	Tongatapu Island	introduced invasive	Space, James C./Flynn, Tim (2001) (p. 9) Voucher: Flynn 6828 (PTBG, MO, US)
Tonga Tongatapu Group	Tongatapu Island		Whistler, W. A. (1992) (p. 74) Vouchers cited: Lawrence 93, Soakai 716
Tonga Tongatapu Group	Tongatapu Island	introduced invasive	Yuncker, T. G. (1959) (pp. 238-239) Voucher cited: Yuncker 15043
Tonga Tongatapu Group	Tongatapu Island		Bishop Museum (Honolulu) (1958) (voucher ID: BISH 41169) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tongatapu Group	Tongatapu Island		Bishop Museum (Honolulu) (1959) (voucher ID: BISH 41371) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tongatapu Group	Tongatapu Island		Bishop Museum (Honolulu) (1953) (voucher ID: BISH 181877) Taxon name on voucher: Solanum mauritianum Scop.
Tonga Tongatapu Group	Tongatapu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2001) (voucher ID: PTBG 255) Taxon name on voucher: Solanum mauritianum
Tonga Vava‘u Group	Vava‘u Island	introduced invasive	Space, James C./Flynn, Tim (2001) (p. 9)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Australia Australia (continental)	Queensland	introduced invasive	Queensland Herbarium (2002) (p. 7)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Owen, S. J. (1997) Naturalized
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 1246) "Around plantations, forest margins, scrub, waste places and similar open situations around settlements".

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Lavergne, Christophe (2006) "Cultivé/très envahissant"
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Kueffer, C./Lavergne, C. (2004) (p. 4)
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Baret, Stephane/Rouget, Mathieu/Richardson, David M./Lavergne, Christophe/Egoh, Benis/Dupont, Joel/Strasberg, Dominique (2006) (p. 758)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1994) (voucher ID: PTBG 16551) Taxon name on voucher: Solanum mauritianum Scop.
French Territory of Mayotte Mayotte Islands	Mayotte Island	introduced invasive	Comité français de l'Union Internationale pour la Conservation de la Nature en France (2013) Envahissant principalement dans les milieux perturbé's.

Comments:  Moderately invasive on Rarotonga, Cook Islands (Meyer, 2000; p. 89). Invasive on Tonga (Space & Flynn, 2001). South African noxious weed (Henderson, 1995; p. 177).

Control: 

Physical:  "Burning is used to kill the plants but may enhance seed germination.  Scattered seedlings can be pulled or dug out.

Chemical:  Larger shrubs and trees can be cut and the cut stumps treated with herbicide.  Follow-up programs are necessary to treat regrowth and seedlings"  (Weber, 2003; p. 406).

"1. Cut and squirt (all year round): make cuts at regular intervals around the trunk, apply undiluted Tordon Brushkiller (1.5ml per cut).
2. Cut and paint stumps (all year round): Tordon Brushkiller or triclopyr 600 EC (100ml/L) or Vigilant gel.
3. Frilling (all year round): Tordon Brushkiller (100ml /L) or triclopyr 600 g/L (100ml/L) or Yates Woody Weedkiller (200ml/L).
4. Injection method: use either 10 mm wide holes drilled at 45 degree angle down into trunk 50 mm deep spaced at 50 mm around trunk, or a series of 80 mm wide blazes cut to a depth of 15-20 mm, spaced at 20-40 mm. Fill each with Vigilant gel.
5. Spray: Tordon Brushkiller (25ml/10L) or triclopyr 600 EC (60ml/10L) or triclopyr 300 EC (12ml/L)"  (Weedbusters New Zealand).