Neem: Classification, Origin, Distribution, Characteristics, and Application
A tropical evergreen tree endemic to the Indian subcontinent, the Neem tree (Azadirachta indica A.Juss.) is also deciduous in drier regions. Due to its therapeutic qualities, it has been utilized in Ayurvedic medicine for over 4,000 years. The Sanskrit word for Neem, “arista,” means “perfect, entire, and imperishable” and is used to describe it. Most plant components, including fruits, seeds, leaves, bark, and roots, contain chemicals with antiseptic, antiviral, antipyretic, anti-inflammatory, anti-ulcer, and antifungal properties. Nimbati swasthyamdadati, which means “to offer good health,” is the root of the Sanskrit name “Nimba.” The ancient texts “Charak-Samhita” and “Susruta-Samhita,” which serve as the cornerstone of the Indian system of natural medicine known as Ayurveda, list neem’s health advantages. It belongs to the Meliaceae family and is sometimes known as “Indian lilac” or “Margosa.” The name “Azad- Darakth- E- Hind” in Persian for neem translates to “Free tree of India.” The Neem tree has received the most research worldwide and is seen to hold the most promise for the 21st century. In the areas of medicine, environmental protection, and pest control, it has a lot of potential. Insecticides, pesticides, and agrochemicals can all be found naturally in neem.
Species: A. indica
Vernacular Names: Nim, Nimgachh, Limbra, Nimb, Indian Lilac, Margosa tree, Neem tree,
Origin and Distribution
Azadirachta has been classified into two species: Azadirachta excelsa Kack, which is only found in the Philippines and Indonesia, and Azadirachta indica A. Juss, which is indigenous to the Indian subcontinent. In India, Bangladesh, Burma, Pakistan, Sri Lanka, Malaysia, Thailand, and Indonesia, the former grows as a wild tree. Neem trees are currently observed flourishing in about 72 nations across Asia, Africa, Australia, North, Central, and South America.
An estimated 25 million trees are flourishing throughout the country, with Karnataka accounting for 5.5 percent of them. Tamilnadu (17.8 percent) and Uttar Pradesh (55.7 percent) take the first and second spots, respectively. Along with Andaman and Nicobar Islands, a Union territory, the other Indian states where neem trees may be seen growing are Andhra Pradesh, Assam, Bihar, Delhi, Gujarat, and Haryana, Himachal Pradesh, Kerala, etc. India leads the world in the production of neem seeds, with an annual production of 4,42,300 tonnes of seeds that result in 88,400 tonnes of neem oil and 3,53,800 tonnes of neem cake.
1. The Neem tree, Azadirachta indica A., is a tropical evergreen that is a member of the Meliaceae family.
2. Neem is a sizable tree that reaches a height of about 25 m, with a semi-straight to straight trunk, a girth of 3 m, and spreading branches that form a broad crown.
3. It is a tree that is at least 40–50 feet tall with a straight trunk, long spreading branches, and a large, spherical crown. Its rough, dark brown bark has wide longitudinal cracks that are divided by flat ridges.
4. After 3-5 years, A Neem tree often begins to bear fruit. It reaches full productivity in around ten years. It can start producing up to 50 Kg of fruits every year in the tenth year.
5. It is said that the plant can live for up to two centuries.
6. The tree can adapt to a variety of climatic, topographic, and edaphic variables. It grows well in shallow soils that are dry, stony, and even have hard calcareous or clay pan. The neem tree needs lots of sunlight and minimal water.
7. The leaves have five to fifteen leaflets per compound, imparipinnate leaf. In turn, the complex leaves alternate with one another.
8. Most often in the leaf axils, it bears several flowering panicles.
9. The selel have ovate petals that are white and oblanciolate, and they are around one cm long.
10. It produces ellipsoid, yellow drupes 12–20 mm long and glabrous.
11. Fruits start green and turn yellow as they ripen. They have a garlic-like scent. In March and April, new leaves and flowers arrive. Fruits can reach maturity anywhere from April to August, depending on location.
12. The pH range for neem tree growth is between 4 and
13. It can grow on practically any sort of soil, including clayey, saline, and alkaline soil, but it thrives in deep, well-drained soil with good subsoil water and black cotton soil.
14. Neem trees have a special ability to mine calcium, which allows them to neutralize acidic soils.
Neem oil is made from the neem tree’s seeds, and because of its insecticidal and therapeutic qualities, it has been used to manage pests in rice farming. When used as a soil amendment or applied to the soil, neem seed cake (the leftover from neem seeds after the oil has been extracted) not only enriches the soil with organic matter but also reduces nitrogen losses by preventing nitrification. It is also effective as a nematicide. Neem leaves are used to make litter compost as well as green leaf manure. Neem leaves are additionally utilized for grain storage. Neem twigs are often integrated into rice production areas as green manure after decomposing. Insecticidal qualities of neem (leaf and seed) extracts have been discovered. It is applied as a foliar spray to treat rice seedlings. Both the bark and the roots of the neem are therapeutic. Fleas and sucking pests are also managed in rice farming using powdered bark and roots. Neem’s anti-bacterial, anti-fungal, and anti-nematicidal qualities have a favorable impact on preventing several diseases in rice production, and there are still many of its active ingredients that can be used.
Neem as Fertilizer
The residue that remains after the oil is extracted from seeds is commonly referred to as seed cake. It serves as a biofertilizer and aids in giving plants the nutrients they need. It is frequently employed to guarantee good crop production. For both food and cash crops, neem is utilized as a fertilizer, particularly for rice and sugarcane.
Benefits: Neem seed cake serves as both a fertilizer and a pesticide, enriches the soil, inhibits the growth of soil insects and bacteria, supplies macronutrients necessary for all plant growth, and contributes to long-term increases in plant yield. It is also biodegradable, environmentally friendly, and a great soil conditioner.
Neem as Manure
Manure is any animal or plant substance used as a fertilizer, particularly animal excrement, to increase the soil’s fertility and so encourage the development of plants. Because of its environmental friendliness and the compounds, it contains, neem manure is becoming more and more popular. These compounds also help to raise the soil’s levels of nitrogen and phosphorus. It contains a lot of nitrogen, potassium, calcium, and other nutrients. High-quality organic or natural manure is produced using neem cake, which has no negative effects on plants, soil, or other living things. High-tech extraction techniques like cold pressing or other solvent extraction can be used to acquire it. For optimal results, it can be mixed with the soil directly or combined with urea and other organic manures like farmyard manure and seaweed.
Benefits include being biodegradable and environmentally friendly, nourishing soil and plants by providing all macro and micronutrients, aiding in the removal of bacteria that cause denitrification of the soil, being ideal for food and cash crops, increasing crop yield, aiding in the reduction of fertilizer usage, which lowers the cost of growing plants, and having antifeedant properties that inhibit the development of insects and pests.
Neem as urea coating agent
To increase and preserve the soil’s fertility, neem and its parts are employed in the production of a urea coating agent. The amount of Nitrogen, Potassium, and Phosphorous in the soil can be used to determine how fertile it is; denitrifying microorganisms can also be discovered in soil. The activity and proliferation of the microorganisms responsible for denitrification are slowed down by the use of a neem urea coating agent. It stops the soil’s urea from evaporating. It can also be used to get rid of a lot of pests like mites, beetles, leafhoppers, borers, and caterpillars. Both liquid and powdered urea coating are typically available. Neem Urea Coating has antifeedant, antifertility, and pest growth regulator properties.
Benefits: Neem Urea Coatings are superior soil conditioners, organic or natural pesticides, environmentally safe, non-toxic, reduce urea usage, convenient, and simple to use. They also boost crop production and have high soil fertility.
Neem as Soil Conditioner
The soil conditioner is made using granulated or powdered neem seed. It can either be sprayed on top of the soil or scraped in during plant sowing. To ensure that the substance reaches the roots, appropriate irrigation should be done after the sprinkler operation. It is a natural soil conditioner that aids in boosting the soil’s quality, which in turn serves to promote the growth of plants and fruits. The use of organic soil conditioners is growing in the agricultural sector, not just in Asian nations like India but also in its western equivalents like the United States, the United Kingdom, and Australia.
Benefits: Neem is a natural soil conditioner that contributes to raising soil quality and promoting plant and fruit growth. It not only promotes plant growth but also guards against certain insects and pests from destroying the plants. In the agriculture sector, organic soil conditioner is becoming more and more popular. They are less expensive than conventional soil conditioners and have no negative side effects because they are organic. Additionally versatile and found in subtropical areas, this natural soil conditioner. The application of neem soil conditioner in plantation crops is well known as a soil enhancer that helps to raise the fertility of the soil.
Neem as pesticide
The use of neem insecticides in agriculture is very common since they are essential for pest management. In general, people are becoming more aware of the negative effects that synthetic pesticides have on living things, including plants, soil, and other living things. As a result, there has been a noticeable shift away from synthetic pesticides to non-synthetic ones around the world. The increased demand for natural or herbal pesticides presents a huge opportunity for makers of neem insecticides to profit. Since the extensive study has been done to determine the neem’s safety and effectiveness for use as a pesticide, neem insecticides are produced and exported to numerous nations. The primary component utilized to make biopesticides is azadirachtin. The germicidal and antibacterial capabilities of neem oil and seed extracts are well recognized and can be used to shield plants from various pests. The fact that neem-based herbicides and insecticides leave no trace on the plants is one of their main benefits. Neem pest management is particularly advantageous for effective crop and pest management.
It is non-toxic, environmentally friendly, and aids in nourishing and conditioning the soil. For increased effectiveness, it can be used in conjunction with other pesticides and oils. It alters the pests’ life cycle rather than eliminating them. The plants are protected by the antifeedant qualities of neem chemicals. Neem-based pesticides often do not cause pests to become resistant. Neem insecticides typically dissolve in water and aid in plant growth. It reduces pest reproduction and serves as a pest deterrent. The agricultural business has likewise made the switch from using synthetic to natural materials. Several issues, including pesticide resistance, harm to other natural enemies of insects, toxic effects on plants and soil, etc., have arisen as a result of the excessive use of synthetic insecticides. Neem is utilized in the production of so-called natural or bioinsecticides, which are safe for the environment and do not harm plants or soil. Both food and economic crops like rice, lentils, cotton, oilseeds, etc. are protected by neem pesticides. Excellent for use on all domestic and commercially grown crops, trees, plants, flowers, fruits, and vegetables. The neem tree’s active component, azadirachtin, works as an insect deterrent and an inhibitor of insect feeding, safeguarding the plants. Tetranortriterpenoids are a class of chemical molecules that this component belongs to. It shares structural similarities with “ecdysones,” which regulate the process of metamorphosis as insects transition from the larval to the pupal to the adult stage. Neem modifies an insect’s life cycle rather than killing it, which is an interesting observation. the primary components/extracts of neem seed used in neem pesticide production. Neem seed extracts include azadirachtin, which prevents the growth of young insects, according to new studies on neem components. Azadirachtin inhibits the development of immature insects. Neem oil, often known as neem seed oil, is frequently used to make pesticides for use on various crops. Neem oil enters the pests’ systems and prevents them from functioning properly. Because insects do not consume food, reproduce, or lay eggs, their life cycle is broken. Neem oil pesticides have the intriguing property of not harming beneficial insects. Only chewing and sucking insects are the focus of neem oil pesticides.
Mode of Action
Neem functions as a biopesticide in a variety of ways and at distinct levels. Because azadirachtin, Salanin, and Melandriol are present in neem products when an insect larva wants to feed on a leaf because it is hungry, but the leaf has been treated with neem products, there is an antiperistaltic wave in the alimentary canal and this causes the insect to feel somewhat like it is vomiting. The insect cannot feed on the neem-treated surface as a result of this sensation, and its ability to swallow is also inhibited. Second, it functions as an oviposition deterrent, preventing the female from depositing eggs, which is especially useful when the stored seeds are coated with neem oil or kernel powder. Additionally, it controls insect growth. The ability of neem products to function on juvenile hormones is a very intriguing quality and rare in nature.
Azadirachtin, Meliacin, Gedunin, Nimbidin, Nimbolides, Salanin, Nimbin, Valassin, and Meliacin form the bitter components of neem oil. The seed also contains tignic acid, which is responsible for the neem oil’s distinct odour. These biologically active components have been isolated from various parts of the plant. Neem kernels have between 30 and 50 percent oil, which is mostly employed in the soap, insecticide, and pharmaceutical sectors. They also have a variety of active chemicals known together as triterpene or limnoids. Azadirachtin, Salannin, Meliantriol, and Nimbin are the four most effective limnoids compounds. The insecticidal and pesticide properties of limonoids are present.