Neem Tree (Azadirachta indica) is native to India, Pakistan and Bangladesh growing in tropical and semi-tropical regions. Its fruits and seeds are the source of neem oil. Neem is a fast-growing tree that can reach a height of 15–20 metres (49–66 ft) and sometimes more. It is evergreen, but in severe drought it may shed most or nearly all of its leaves. The branches are wide spread. The fairly dense crown is roundish or oval and may reach the diameter of 15–20 metres.
In India, the plant is variously known as "Sacred Tree," "Heal All," "Nature's Drugstore," "Village Pharmacy" and "Panacea for all diseases". Products made from neem trees have been used in India for over two millennia for their medicinal properties: neem products are believed to be anthelmintic, antifungal, antidiabetic, antibacterial, antiviral, contraceptive and sedative. Neem products are also used in selectively controlling pests in plants. It is considered a major component in Ayurvedic and Unani medicine and is particularly prescribed for skin disease. In trials neem oil has suppressed several species of pathogenic bacteria including Staphylococcus & Salmonella spp.
Neem has proved effective against certain fungi that infect the human body. Such fungi are an increasing problems & have been difficult to control by synthetic fungicides.
Neem is a key ingredient in non-pesticidal management (NPM), providing a natural alternative to synthetic pesticides. Neem seeds are ground into a powder that is soaked overnight in water and sprayed onto the crop. To be effective, it is necessary to apply repeatedly, at least every ten days. Neem does not directly kill insects on the crop. It acts as an anti-feedant, repellent, and egg-laying deterrent, protecting the crop from damage. The insects starve and die within a few days. Neem also suppresses the hatching of pest insects from their eggs. Neem cake is often sold as a fertilizer.
Ancient practice & initial testing of neem derivatives against various livestock pests indicated that this is an area of particular promise for the future. Insects of veterinary importance are obvious targets for neem products.
One of the first active ingredients isolated from neem, Azadirachtin has proved to be the trees main agent for battling insects. It appears to cause some 90% of the effect on most pests.
Traditional Ayurvedic uses of neem include the treatment of acne, fever, leprosy, malaria, ophthalmia and tuberculosis. Various folk remedies for neem include use as an anthelmintic, antifeedant, antiseptic, diuretic, emmenagogue, contraceptive, febrifuge, parasiticide, pediculocide and insecticide. It has been used in traditional medicine for the treatment of tetanus, urticaria, eczema, scrofula and erysipelas. Traditional routes of administration of neem extracts included oral, vaginal and topical use. Neem oil has an extensive history of human use in India and surrounding regions for a variety of therapeutic purposes. Puri (1999) has given an account of traditional uses and therapeutic indications and pharmacological studies of this oil, in his book on neem.
Formulations made of neem oil also find wide usage as a biopesticide for organic farming, as it repels a wide variety of pests including the mealy bug, beet armyworm, aphids, the cabbage worm, thrips, whiteflies, mites, fungus gnats, beetles, moth larvae, mushroom flies, leafminers, caterpillars, locust, nematodes and the Japanese beetle. Neem oil is not known to be harmful to mammals, birds, earthworms or some beneficial insects such as butterflies, honeybees and ladybugs if it is not concentrated directly into their area of habitat or on their food source. It can be used as a household pesticide for ant, bedbug, cockroach, housefly, sand fly, snail, termite and mosquitoes both as repellent and larvicide (Puri 1999). Neem oil also controls black spot, powdery mildew, anthracnose and rust (fungus). (Puri, H.S. (1999) Neem: The Divine Tree. Azadirachta indica. Harwood Academic Publications, Amsterdam.)
Source: Wikipedia (All text is available under the terms of the Creative Commons Attribution-ShareAlike License)