Nicotiana glauca (Tree Tobacco)

Scientific name

Nicotiana glaucaGraham

Synonyms

Nicotiana glauca var. angustifolia Comes; Nicotiana glauca var. decurrens Comes; Nicotiana glauca var. grandifloraComes

Common names

Mustard tree, tobacco bush, tobacco plant, tobacco tree, tree tobacco, wild tobacco

Family

Solanaceae

Origin

Native to South America.

Naturalised distribution (global)

Locations within which Nicotiana glauca is naturalised include Australia, warmer parts of Europe, sub-Saharan Africa, temperate Asia, New Zealand, USA, Mexico and Hawaii.

Introduced, naturalised or invasive in East Africa

Nicotiana glauca is present in Kenya, Tanzania and Uganda. It is invasive in parts of Kenya (A.B.R. Witt pers. obs.) and Tanzania (Henderson 2002).

Habitat

Nicotiana glauca grows in a wide variety of open and disturbed habitats including roadsides and lakeshores. It is mainly a problem in relatively dry areas.

Description

Nicotiana glauca is a much branched shrub or small tree that normally grows to a height of more than 2 m. It can reach 7 m in height.

Its leaves are thick and rubbery up to 20 cm long. It has yellow tubular flowers about 5 cm long and 1 cm wide.

Reproduction and dispersal

This plant reproduces by seed.

Economic and other uses

Nicotiana glauca is an ornamental plant. It has insecticidal properties. However, these uses cannot compensate for this plant's overall negative impacts.

Environmental and other impacts

Nicotiana glauca poses a threat to biodiversity by competing with native species for resources and displacing native plants. All parts of the plant are poisonous. N. glauca has been included in the Global Invasive Species Database (GISD 2010). It has been listed as a noxious weed in South Africa (prohibited plants that must be controlled. They serve no economic purpose and possess characteristics that are harmful to humans, animals or the environment).

Management

The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species. Some components of an integrated management approach are introduced below.

The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.

Seedlings and young plants can be pulled or dug out. Larger plants can be cut and the stumps treated with herbicide. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

The beetle Malabris aculeata has been released as a biological control agent for this species and has been successful when used as part of an integrated management programme (Cronk and Fuller, 2001).

Legislation

Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.

References

Cronk,  Q.C.B. and Fuller, J.L. (1995). Plant Invaders. Chapman and Hall, London. 

Henderson, L. (2001).  Alien weeds and invasive plants. A complete guide to declared weeds and invaders in South Africa.  Plant Protection Research Institute Handbook No. 12, 300pp. PPR, ARC South Africa.

Global Invasive Species Database online data sheet. Nicotiana glauca. www.issg.org/database. Accessed March 2011.

Pacific Island Ecosystems at Risk (PIER). Nicotiana glauca R.C.Graham, Solanaceae: plant threats to Pacific ecosystems. www.hear.org/pier/species/nicotiana_glauca.htm. Institute of Pacific Islands Forestry, Hawaii, USA.

Editors

Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.

Acknowledgments

This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke