Family: Meliaceae
Genus: Melia
Species: azadirachta
(i) General background on the plant
The Neem tree is a deep-rooted, broad-leaved, evergreen tree which can grow to a height of about 30 metres and 2.5m girth. The trunk is usually short and straight with fairly thick, strongly furrowed bark. The spreading branches can form a rounded crown of up to 10m across. Flowers are white and bisexual and are borne in axillary clusters with a honey-like scent that attracts bees. The fruit is almost 2cm long, smooth and ellipsoidal. Ripe fruits are yellow-green and contain a sweet pulp enclosing a seed. The seed is a shell and a kernel.
Neem grows on well-drained soils in hot, dry conditions and can be found growing wild in the dry forest of Deccan and in the open dry scrub of the dry zones of Burma, but is now cultivated all over India and Burma. NAS (1980) describes it as a native to dry forests of India, Pakistan, Sri Lanka, Malaya, Indonesia, Thailand, and Burma. It has grown well in plantations in the Sudan and Sahelian zones of Africa as well as in Sierra Leone, Malawi, Zimbabwe, Tanzania, Zanzibar and the non-Sahelian areas of Nigeria, and Ghana.
(ii) Details of quality characters
Seeds of the Neem tree contain approximately 20 to 45% oil with the following fatty acid composition:
53% Oleic
18% Stearic
14% Palmitic
Small amounts of linoleic and arachidic acid can also be found (Duke and duCellier, 1993)
The gum exuding from the bark contains 13-15% water, 3% ash, 12% galactans, 25% pentosans, with some albumins and oxidase.
Fruits contain the toxic alkaloid azaridin. According to USDA reports low doses (0.1 ppm) of a Neem extract called azadirachtin protected plant leaves from Coleopteras, while control leaves were completely destroyed by beetles. Wheat, barley, rice, sugar cane, tomatoes, cotton and chrysanthemums were protected from insect damage for 10 weeks after 1% Neem dust was applied to the soil in which the plants were growing. The systemic protection persisted despite heavy rains.
(iii) Current production and yields
A single tree can yield up to 50 kg fruit (National Academy of Sciences 1992) and may live two centuries. Duke (1993) estimates annual productivity of 2-21 tonnes/ha.
(iv) Constraints on production
The climatic requirements of the Neem tree make it unsuitable for commercial production in Europe.
(v) Markets and Market potential
The first step towards the commercial development and marketing of Neem formulations for controlling agricultural pests in the USA is being made by a private concern which is to be granted registration by the Environmental Protection Agency (EPA) for use on non-food crops.
Oil from the seed, which though malodorous, could be used for lubrication or energy.
(vi) Other Information
See the following pages in the NF-2000 Database
(vii) Contacts
(viii) References
Duke, J A and duCellier, J L (1993) CRL Handbook of Alternative Cash Crops. CRE press London.
NAS (1980) Firewood crops. Shrub and Tree species for Energy production, National Academy of Sciences, Washington DC 1980.
National Academy of Sciences (1992) NEEM: A tree for solving Global problems, National Academy of Sciences, Washington DC.