Out of the comments about the DDT post

Came the discussion on Neem oil and its ability to be an insecticide to replace DDT. I have never heard of the Neem tree or its oil.

Wikipedia's entry:

Neem oil is not used for cooking purposes but, in India and Bangladesh, it is used for preparing cosmetics (soap, hair products, body hygiene creams, hand creams) and in Ayurvedic, Unani and folklore traditional medicine, in the treatment of a wide range of afflictions. The most frequently reported indications in ancient Ayurvedic writings are skin diseases, inflammations and fevers, and more recently rheumatic disorders, insect repellent and insecticide effects.

Traditional Ayurvedic uses of neem include the treatment of 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 bio-pesticide for organic farming, as it repels a wide variety of pests including the mealy bug, beet armyworm, aphids, the cabbage worm, nematodes and the Japanese beetle. Neem Oil is not known to be harmful to mammals and birds as well as many beneficial insects such as honeybees and ladybugs. 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).

For use as a bio-pesticide, pure Neem oil should be diluted at the rate of 1 teaspoon per quart or 4 teaspoons per gallon of water. Adding a surfactant greatly enhances its effectiveness. It can also be used as a cure for Static Lice in Cavies (Guinea Pigs).

The Neem tree (Wikipedia again):

Usage

In India, the tree is variously known as "Divine Tree", "Heal All", "Nature's Drugstore", "Village Pharmacy" and "Panacea for all diseases". Products made from neem have proven medicinal properties, being antihelmintic, antifungal, antidiabetic, antibacterial, antiviral and anti-infertility. It is particularly prescribed for skin disease (Puri, 1999).

• Neem twigs are used for brushing teeth in India, Bangladesh and Pakistan. This practice is perhaps one of the earliest and most effective forms of dental care.

• All parts of the tree (seeds, leaves, flowers and bark) are used for preparing many different medical preparation.

• Neem Oil is used for preparing cosmetics (soap, shampoo, balms and creams).

• Besides its use in traditional Indian medicine the neem tree is of great importance for its anti-desertification properties and possibly as a good carbon dioxide sink.

• Neem oil is useful for skin care such as acne, and keeping skin elasticity.

• Practictioners of traditional Indian medicine recommend that patients suffering from Chicken Pox sleep on neem leaves.

• Neem Gum is used as a bulking agent and for the preparation of special purpose food (those for diabetics).

[edit] Horticultural usages

Neem is a source of environment-friendly biopesticides. Among the isolated neem constituents, limonoids (such as Azadirachtin) are effective in insect growth-regulating activity. The unique feature of neem products is that they do not directly kill the pests, but alter the life-processing behavior in such a manner that the insect can no longer feed, breed or undergo metamorphosis.[3] However, this does not mean that the plant extracts are harmful to all insects. Since, to be effective, the product has to be ingested, only the insects that feed on plant tissues succumb. Those that feed on nectar or other insects (such as spiders, butterflies, bees, and ladybugs) hardly accumulate significant concentrations of neem products.

[edit] Uses in pest and disease control

Neem is deemed very effective in the treatment of scabies although only preliminary scientific proof exists which still has to be corroborated, and is recommended for those who are sensitive to permethrin, a known insecticide which might be an irritant. Also, the scabies mite has yet to become resistant to neem, so in persistent cases neem has been shown to be very effective. There is also anecdotal evidence of its effectiveness in treating infestations of head lice in humans. It is also very good[citation needed] for treating worms (soak the branches and leaves in lukewarm water and then drink it).

[edit] Culinary use

The tender shoots and flowers of the neem tree are eaten as a vegetable in India. Neem flowers are very popular for their use in Ugadi Pachadi (soup-like pickle)recipe which is made on Ugadi day in South India.

Neem is also used in parts of mainland Southeast Asia, particularly in Cambodia (where it is known as sadao or sdao), Laos (where it is called kadao) and Vietnam (where it is called sầu đâu).recipe. Even lightly cooked, the flavour is quite bitter and thus the food is not enjoyed by all inhabitants of these nations, though it is believed to be good for one's health.

The Neem tree is hardy and drought resistant although it cannot handle cold temperatures very well. (Beware the look-alike Chinaberry tree which is completely poisonous.)

If the synthetic Neem Oil has taken 22 years to develop as Bug_Girl says, and Neem plantations are not viewed as profitable, could there be a drive to plant more trees about the southwest? The oil comes from seeds, how many trees are needed to make it worth while?

And, while we are talking about plants with beneficial properties, whig of Cannablog often reminds me that hemp was an excellent plant to use for oil, rope, cloth and much more (and no, not pot).