ALIEN INVASIVE PLANT OF THE MONTH

Scientific Name: Solanum mauritianum

Common Name: Bugweed, Wild Tobacco Zulu Name: uBhongabhonga Invasive Status: CATEGORY 1 Countries of Origin: South America (NE Argentina, S Brazil, Paraguay & Uraguay) Toxicity Status: POISONOUS TO HUMANS Flowers: Purple, in compact terminal clusters on densely felty stalks up to 100 mm long, all year Fruits: Globose berries 10 mm across, green turning yellow, in compact terminal clusters

Solanum mauritianum/Bugweed, Wild Tobacco, was introduced accidentally and also deliberately for ornamental purposes. It is an aggressive fast growing invader of disturbed areas, as well as indigenous forests, commercial plantations, open grasslands, roadsides, under power lines, watercourses and urban open space, particularly in the Eastern higher rainfall regions of the country.

It is very fast growing and seedlings that become established in Summer can flower by Autumn. They will grow to a height of several metres within 2-3 years and have a life of up to 30 years, during which time the plant can attain a height of up to 10 metres. Its large oval leaves are grey-green in colour and covered with felt-like hairs and when crushed have a strong smell of diesel fuel. The flower is purple with a yellow center. The plant can flower year round but fruiting occurs from late Spring to early Summer. There are between 20-80 berries borne on each inflorescence, which on average contain between 150 to 200 seeds per berry. Fruit eating birds, particularly the African Olive-Pigeon (Rameron Pigeon) as well as Trumpeter Hornbills, Bulbuls, Barbets and many others, favour bugweed fruits and can be responsible for dispersal of seed over long-distances. The fruit is poisonous to many other organisms, including humans, but does not affect the fruit eating birds that are responsible for the distribution of seed. Seedlings are often found growing under trees, where roosting birds drop the seed. Seed is also spread by animals, such as fruit bats, as well as by the dumping contaminated garden waste. Germination of soil stored seed is stimulated by fire. It is tolerant of many soil types and quickly becomes established around plantations, forest margins, scrub and open land.

The main toxic compound in Solanum mauritianum is the steroid alkaloid solasodine and all parts of the plant are poisonous to humans, especially the fruit berries. Cattle, sheep and pigs are also affected, but toxicity to goats is considered to be of relatively low risk. It has hairy stems and leaves and the handling of any parts of the plants can cause skin irritation and nausea. The dust from the Solanum mauritianum plant can cause respiratory tract problems if exposure is prolonged. Apart from being poisonous, the fruit acts as a host and food source for the over-Wintering Mediterranean and Natal fruit fly, which is a serious pest in fruit orchards.

Because Solanum mauritianum is a fast growing aggressive invader plant and has the ability to affect human health, it has been classified as a Category 1 invader and is therefore illegal to sell, propagate, or distribute any part of this plant.

For further information and reading on the matter, you are invited to refer to the following: Alien Weeds and Invasive Plants by Lesley Henderson. A Field Guide to WILD FLOWERS KWA-ZULU NATAL and the Eastern Region by Elsa Pooley. Problem Plants and Alien Weeds of South Africa by Clive Bromilow.

Also a few websites of interest:

http://www.arc.agric.za/home.asp?pid=1031 http://www.sanparks.org/parks/kruger/conservation/scientific/ff/alien_biot a/layout.pdf http://en.wikipedia.org/wiki/Solanum_mauritianum http://www.hear.org/pier/species/solanum_mauritianum.htm http://www.issg.org/database/species/ecology.asp?fr=1&si=209 http://www.weeds.mangrovemountain.net/data/Solanum%20mauritianum %20-%20Wild%20tobacco%20tree.pdf http://www.nzpps.org/journal/57/nzpp_570980.pdf http://www.ebooks.cambridge.org/chapter.jsf?bid=CBO9780511576348&c id=CBO9780511576348A028

Should you reside in Mtunzini or surrounds and would like to contact someone from the Mtunzini Conservancy for further advice, or assistance in dealing with Alien Invasive Plants, or assistance in identifying which are Alien Invasive Plants, or which plants are soon to be promulgated as Alien Invasive Plants, please contact anyone of the following persons, who will gladly assist you:

Mike Butler – 083 654 3010 Doggy Kewley - 083 630 1839 Jim Chedzey - 083 326 0698 For advice on alternative indigenous plants which are best suited to be planted in the space that has been cleared of Aliens, ask any of the persons above, or:

Bruce Hopwood - 083 301 2958 Jonathan Cromhout - 083 630 6466

The Mtunzini Conservancy is a non-profit Section 21 Company that is continually striving for the betterment of our environment.

PS – Should you either reside in, or are due to visit Mtunzini, please take the time to visit & view the Mtunzini Conservancy’s Alien Invasive Plant of the Month display stand located on the pavement outside the entrance to MTUNZINI SPAR, to view a growing specimen of the Solanum mauritianum/Bugweed, Wild Tobacco plant.