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By Laxmikant Padole, Coordinator, NRTDC, Neem Foundation,
And
Mrs. Pramila Thakkar, Managing Trustee, Neem Foundation, Mumbai
________________________________________ Introduction India is a largely agrarian society with more than hundred million families dependant on farming for a living. The liberalized Indian economy still depends on the success of agricultural production and 35 – 40% of India’s National Income comes from agricultural sources. India will require 250 million tones of food by 2010 AD. At the present rate of food production, which is 200 million tones annually, it will not be possible to meet the food needs of the burgeoning population. Agriculture in India has been practiced for more than 5000 years. Till around 1950, the land was nurtured with care using natural resources and organic materials. Chemical fertilizers and pesticides were unheard of and cattle were a major component of the agriculture. The eminent agricultural scientist, Albert Howard, wrote early in this century that Indian farmers used compost and organic manures, which ensured that they could continue farming on the same land for more than 2000 years without a drop in yields. He added that the crops were remarkably free from pests and that they were nearly as permanent as the primeval forest. Pest control, as practiced today in most developing countries relies mainly on the use of imported pesticides. This dependence has to be reduced. Although pesticides are generally profitable on direct crop returns basis, their use often leads to the contamination of terrestrial and aquatic environments, damage to beneficial insects and wild biota, accidental poisoning of humans and livestock, and the twin problems of pest resistance and resurgence. Scenario of Crop Pest in India (Source O.P. Dubey, Assistant Director General (PP), ICAR, New Delhi)
| Crop | 1920-40 | At Present | | | Total Insect Pest | Serious Pest | Total Insect Pest | Serious Pest | | Rice | 35 | 10 | 240 | 17 | | Wheat | 20 | 2 | 100 | 19 | | Sugarcane | 28 | 2 | 240 | 43 | | Groundnut | 10 | 4 | 100 | 12 | | Mustard | 10 | 4 | 38 | 12 | | Pulses | 35 | 6 | 250 | 34 | | Cotton | 34 | 9 | 162 | 15 | More than 500 arthropods pest species have become resistant to one or more insecticides. Resistance of the cotton bollworm, Helicoverpa armigera, in India and Pakistan, and of the Colorado potato beetle, Leptinotarsa decemlineata, in the USA to all available insecticides, and resistance of the diamondback moth, Plutella xylostella, to all classes of insecticides, including Bacillus thuringiensis, in Hawaii, Malaysia, the Philippines, Taiwan, and Thailand, illustrate the complexity of the problem. Shifts in pest status-from minor to major, and resurgence of pests, such as white flies, caused by direct or indirect destruction of pest’s natural enemies are other unwelcome developments associated with pesticide use. A World Health Organization and United Nations Environmental Programme report (WHO/UNEP 1989) estimated there are 1 million human pesticide-poisoning cases each year in the world, with about 20,000 deaths, mostly in developing countries. The problem is rendered even more difficult because few, if any, new compounds are coming to replace old insecticides. The cost of developing and registering new pesticides is staggering almost US$ 60 million, and pesticide manufacturers are unwilling to risk investments on products whose market life could be shortened by development of pest resistance. For ecologically sound, equitable, and ethical pest management, there is a need for control agents that are pest-specific, nontoxic to humans and other biota, biodegradable, less prone to pest resistance and resurgence, and relatively less expensive. Among various options, neem has been identified a source of environmentally "soft" natural pesticides. In the traditional Indian farming system nutrient supply and pest management were integrated not only into the cropping system as a whole but also into their way of life. Locally available plant derived substances like Neem, Karanj, Tulsi; Vidang etc. protected the crops and nourished the soils. It is evident that the traditional Indian practices, in the pre-green revolution era were very sound, causing no major plant protection problems and these need to be refined by incorporating latest scientific and technical developments to arrive at crop practices that are best suited to the present agricultural situation. Neem has much to offer in solving global agricultural, environmental and public health problems. It has been recognized as a valuable instrument for sustainable development. Products derived from the seeds of the Neem tree act as powerful Insect Growth Regulators (IGR). They also help in controlling several nematodes and fungi. Neem products are very effective in the control of larval (instars), through pupal stages. They reduce insect populations. Neem products are extensive grower tested and university proven effective against aphids, thrips, whiteflies, leaf miners, mealy bugs and a host of other key insect pests. Neem products also act as natural insect repellants. Azadirachtin and other bitter compounds in Neem make insects stay away from treated plants. Many insects prefer to starve rather than feed on neem treated plants. This helps minimize overall damage to plants, especially from adults. Neem can help reduce usage of chemical insecticides and more importantly can reduce overall insecticide usage, as Neem actually affects insects’ tolerance to other insecticides and can make them more vulnerable at lower rates. The currently preferred active ingredient of Neem – Azadirachtin has shown no evidence of insect resistance. Growers can use it with absolutely no fear of resistance when used either continuously or in combination with other insecticides. Neem products are safe for the workers. They are no handling risks and no minimum re-entry time interval is allowable. Neem is non-phytotoxic and has no adverse effect on beneficial insects. Neem is ideal for both conventional and IPM programmes and can be used throughout the entire crop production cycle. It can be dipped, drenched, mixed with liquid fertilizers in drip systems and applied with all spray equipment including thermal fog and ultra low volume systems. The oral LD – 50 of Azadirachtin is greater than 5000 mg / kg in rats. Neem is thus less acutely toxic (according to LD – 50 in mg / kg in rats), than Table salt (3750), Aspirin (1200), Caffeine (250), Nicotine (50), While Pyrethrum (900 – 1500) and Rotenone (150 1500) are relatively safe and have been used over a period of time, Neem products are among the safest. Extensive toxicological studies have been carried out on Neem products in the US and have been finally cleared for use in horticulture by the EPA. Neem and Neem Extracts and other natural products like Equisetum, Reynoutria, Pyrethrum, Rotenone, Quassia, Ryania, Sabadilla are permitted to be used in organics in the US and are classified as biorationals. India will have to take lead and provide leadership as Azadirachta indica is a tree of Indian origin and more than 60% of its germplasm is to be found in India. India also has a vast repository of Neem knowledge. The increasing awareness about the potential of Neem and its importance need to be translated into actual economic and environmental benefits for the country. In India nearly 100 Oil Mills and 40 Biopesticide Units have a requirement of more than 5 lakh tones of seed annually. However, collection and transport of Neem seed continued to be disorganized resulting in poor quality raw material. The current production of 1500 kilolitres of Neem Pesticide is valued at Rs. 15 cores. It is estimated that high quality, standardized Neem Pesticides will have a market of 100 cores in the next couple of years. The value of these formulations in the international market amounts to approx. US$ 100 million. Neem Based Pesticides are expected to achieve more than 10% share of the 6 billion dollars world pesticide market, which equals to 600 million dollars. India has an immense advantage in utilizing this opportunity of production and export of Neem based products. However, the Neem Industry is faced with hurdles every step of the way and predictably is yet to find a firm footing both nationally and internationally. HISTORY OF NEEM: The commercial use of neem was known from the Vedic period in India over 4000 years B.C. and the domestic uses have been mentioned by Kautilya in his Arthashastra (4th Century B.C.). The varied uses of Neem as a medicine have been documented in the Atharva Veda, the Grihathyasutras and also in the Sutragranthas. The Puranas cite it as a cure for Kushtaroga (leprosy). In fact, the Sanskrit name, Nimba is a derivative of the term Nimbati svasthyamdadati (to give good health). Its medicinal properties are described in the ‘Puranas’ and neem is commonly used in ‘Ayurvedic’ and ‘Unani’ medicine. The tree has relieved so many different pains, fevers, infections and other complaints that it is often referred to as the Village Pharmacy.
TRADITIONAL USES: The Upavanavinod is an ancient Sanskrit treatise dealing with forestry, horticulture and agriculture; the neem finds prominence here as cure for ailing soils, for ailing plants and for ailing livestock. Varahamihira’s Brihat Samhita has a chapter of verses on Plant medicine containing a description of the trees that should be planted near one’s house. The Neem is highly recommended.
In Ayurvedic medicine system Neem is used to treat malarial fevers. Recent experiments have shown that one of Neem’s components, gedunin (a liminoid), is as effective as quinine against malaria. Malaria affects millions of people and is responsible for about 2 million deaths every year in India and several other countries.
Neem has also been traditionally used against various livestock insects such as maggots, horn flies, blowflies and biting flies. Neem is also useful for controlling some bacteria of veterinary importance and against intestinal worms in animals. Patnaik (1993) highlights the friendly medicinal role of Neem in the following “the tree (Neem) is revered by Indian herdsmen as a gentle but effective veterinary poultice, a virtue confirmed by the 16th Century Portuguese botanist and traveler, Garciada Orta in his “Coloquios”.
THE NEEM | Botanical Name | : | Azadirachta indica | | Family | : | Meliaceae | | Subfamily | : | Melioideae | | Tribe | : | Melieae | | Common Name | : | Nim, Neem, Limba, and Nimba etc. | In India neem occurs in tropical dry deciduous and thorn forests (Champion and Seth, 1968) and in the drier parts up to 1500m. This amazing tree lives for over 200 years and can thrive well under semi-arid and sub-humid conditions up to 700 meters above sea level. It is tolerant to soil and even drought. It is favored for afforestation of dry areas for checking soil erosion and as windbreak. Neem is a moderate to large tree with a stout and rather short stem, generally branching early and forming a large, fairly dense and rounded crown of bright green foliage. Normally, it attains a height of 12-15m, rarely unto 25m, and a girth of 1.8-2.5m. Neem grows on most types of soils. It can grow on compact clay or laterite crusts, however black cotton soils are preferred. It comes up well in moderately saline and alkali soils with high levels of sodium carbonate and bicarbonates. It is a popular shade and avenue tree. The Neem has been extensively planted through the centuries all over the Indian countryside. It thrives better than most other species on dry, stony shallow soils where vegetation is scarce. Neem does best where drainage is good and the subsoil water level is fairly high, but it can persist even under very adverse soil conditions. If soil conditions are adverse, soil management and irrigation management can improve its establishment and growth. Neem is a light demander; it has a great capacity for pushing its way through thorny shrub in the seedling stage. It is drought-hardy and can withstand drought better than excessive rainfall, as its root travel long distances in search of water from the sub-soil. It can grow in temperatures from 0º C to 50ºC. It can withstand rainfall of 450 to 1150 mm per year although neem grows on sites with as little as 250 mm rainfalls. Neem seeds are collected from June-August in rainy season. There are normally 3500 to 5000 seeds per kilogram. The tree in wind-firm, the branches are seldom broken even in storms. | Neem part and products | Aza content (%) | | Neem oil | 0.01-0.1 | | Az-enriched oil | 0.1-1.0 | | Seed Cake | 0.005-1.2 | | Seed Kernels | 0.35-0.89 | | Aqueous extract | 0.001-0.02 | NEEM IN PEST MANAGEMENT Unlike chemical insecticides, neem compounds work on the insect’s hormonal system, not on the digestive or nervous system and therefore doe not lead to development of resistance in future generations. These compounds belong to a general class of natural products called ‘limonoids’. The liminoids present in neem make it a harmless and effective insecticides, pesticide, nematicide, fungicide etc. The most significant liminoids found in neem with proven ability to block insect growth are: azadirachtin, salanin, meliantriol and nimbin. Azadirachtin is currently considered as neem’s main agent for controlling insects. ‘It appears to cause 90% of the effect on most pests. It does not kill insects – at least not immediately – instead it both repels and disrupts their growth and reproduction. Research over the past years has shown that it is the most potent growth regulator and feeding deterrent ever assayed. It will repel or reduce the feeding of many species of pest insects as well as some nematodes. In fact, it is so potent that a mere trace of its presence prevents some insects from even touching plants.’
On an average 18 % of the crop yield is lost due to Pest with annual monetary loss 60,000 cores.
The pest control potential of neem in developing countries, however, remained largely untapped due to the advent of DDT and other and other broad-spectrum synthetic insecticides. Also, wide publicity given to slogans such as "the only good bug is a dead bug" and identifying traditional uses of neem as backward, gradually influenced people away from using neem. It is only in the past decade, that the pest control potential of neem, which does not kill pests but affects their behavior and physiology, has been recognized. Though subtle, neem's effects such as repellence, feeding and oviposition deterrence, growth inhibition, mating disruption, chemo-sterilization etc. are now considered far more desirable than a quick knock-down in integrated pest management programs as they reduce the risk of exposing pests natural enemies to poisoned food or starvation.
ACTION OF NEEM ON INSECT PEST Certain hormones are necessary for growth and development of insects. These hormones control the process of metamorphosis as the insects pass from larva to pupa to adult. Azadirachtin blocks those parts of the insect’s brain that produce these vital hormones. As a result, insects are unable to molt. It is through these subtle hormonal effects that this important compound of neem breaks the life cycle of insects. The insect populations decline drastically as they become unable to reproduce. Meliantriol and salannin act as powerful antifeedants. Nimbin as well as nimbidin (another neem component) have antiviral property. The neem products especially azadirachtin enter into the body of larvae the activity of ecdysone enzyme is suppressed and the larva fails to molt, remains in larval stage and ultimately dies. If larva manages to enter the pupal stage due to low aza concentration it dies and still at low concentration of aza the adult emerging from the pupa is 100 % malformed, absolutely sterile without any capacity for reproduction.
But, for all the uncertainty over details, various neem extracts are known to act on various insects by
- Disrupting or inhibiting the development of eggs, larvae or pupae.
- Blocking the molting of larvae or nymphs
- Disrupting mating and sexual communication
- Repelling larvae and adults
- Deterring females from laying eggs
- Sterilizing adults
- Poisoning larvae and adults
- Deterring feeding
- Blocking the ability to “swallow” (that is, reducing the motility of the gut)
- Sending metamorphosis awry at various stages
- Inhibiting the formation of chitin.
All these effects listed above are not equally strong or certain. Blocking the larvae from molting is considered to be neem’s most important quality, which can be used to eliminate many pest species. Neem products are harmless to most insect eaters, humans and other mammals, except certain marine life like crabs, lobsters, fishes and tadpoles. In spite of high selectivity, neem derivatives affect ca. 400 to 500 species of insects belonging to Blattodea, Caelifers, Dermaptera, Diptera, Ensifera, Hetroptera, Hymenoptera, Isoptera, Lepidoptera, Phasmida, Phthiraptera, Siphonoptera and Thysanoptera, one species of ostracad, several species of mites, and nematodes and even noxious snails and fungi, including aflatoxin-producing Aspergillus flavus. Results of field trials in some major food crops in tropical countries will illustrate the value of neem based pest management for enhancing agricultural productivity in Asia and Africa. | Order | Insect | Action | Critical Stages of Insect | | Orthoptera | Grasshoppers, crickets, Katydids | Antifeedent, | Adult | | Homoptera | Cicadas, Aphids, Scale insects, leaf hoppers | Antifeedent, Growth Regulators | Larvae and Adults | | Thysonoptera | Thrips | Growth Regulators | Larvae in soil, adults | | Coleoptera | Beetles, Weevils | Antifeedent, Growth Retardant | Larvae | | Lepidoptera | Moths, Skippers, Millers, Butterflies | Growth deterrent, antifeedent | Larvae | | Diptera | Flies | Repellent | Adult | | Hymenoptera | Bees, Wasps, Saw flies, ants | Antifeedent, Growth regulators | Larvae | | Heteroptera | Bugs | Antifeedent, Growth deterrent | Adults | NEEM ON THE MAJOR PESTS | Pest | Mode of Action | | Desert Locust | Neem oil causes solitarization of gregarious nymphs at 2.5 l/ha. They became solitary, lethargic, almost motionless and highly susceptible to predators like birds | | Cockroach | Neem seed extracts kills young cockroaches. Adults inhibited from laying eggs | | Green Leaf Hoppers | Inhibits feeding | | Brown Plant Hoppers | Reduction in survival, affect the development of nymphs to adults stage, oviposition deterrent, sterility, repellent, mating failure | | Mosquito | Throwing crush neem seed in ponds prevent breeding, affect larvae | | Mexican Bean Beetle | Retard growth, inhibit feeding, disrupt molting | | Khapra Beetle | Inhibits feeding, disrupt molting, toxic to larvae | | Bean Aphid | Reduces fecundity, disrupt molting | | Diamond Back Moth | Strongly suppresses larvae and pupae, retard growth, Inhibit feeding | | Pink Boll Worm | Retard growth, Inhibit feeding | | Army Worm | Retard growth, Repel adult, Inhibit feeding, Disrupt molting, Toxic to larvae | | Mealy Bugs | Repelles, Inhibit feeding | | Rice, Cowpea and Boll Weevils | Inhibit feeding, Disrupt growth, toxic | | Cabbage loopers | Inhibit feeding | | Rice gall midge | Toxic | | Gypsy Moth | Retard growth, Inhibit feeding, Disrupt molting | | Leaf Minor | Larvae unable to molt, Retard Growth,Inhibit Feeding, Toxic | | Fire ant | Inhibit feeding, Disrupt growth | | Fruit flies | Repellent, (100 % control by neem spay under tree) | | Nematode | Inhibit hatching, prevent second stage juvenile(neem cake) | | White fly | Repellent, growth retardent, feeding inhibitor | | Sorghum shoot fly | Feeding inhibitor | | Spotted cucumber beetle | Growth retardent, feeding inhibitor | | Snails | Kills snails | Also, as early as 1930, neem cake was applied to rice and sugarcane fields against stem borers and white ants. Some innovative farmers in Karnataka and Tamil Nadu states in India even today "puddle" green twigs and leaves in rice nursery beds to produce robust seedling and simultaneously ward-off attack by early pests-leafhoppers, plant hoppers, and whorl maggots. Neem is quite effective against armyworm, one of the most devastating pests of food crops in the western hemisphere. Azadirachtin in extremely low concentrations – a mere 10 mg per hectare – inhibits the pests. Neem extract is useful against leaf miner, a serious pest in parts of North America. Neem seed extract works as well as available commercial synthetic pesticides. It has been approved by the US Environmental Protection Agency for use on leaf miners. Neem in extremely useful as an anti-feedent and ovipositional repellent for protection of crops like tobacco, groundnut, cotton and sweet potato from the damages caused by tobacco caterpillar or tobacco cutworm, a serious polyphagous pest of several crops in India. Neem products are quite effective against the larvae of a number of mosquito species which stop feeding and die after treatment. At present developing countries use expensive imported pesticides to control mosquito population. These countries can save a lot of money by using locally available simple neem products which are equally effective. Experiments have shown that neem is also effective against fruit flies. Med fly, one of the most damaging horticulture pests, can be controlled by spraying neem solution under fruit trees. Neem has an advantage over the currently used pesticides. Whereas the conventional pesticides kill fruit flies as well as their internal parasites, neem products on the other hand, leave the biological-control organisms unaffected; they only kill fruit flies. This reduces, in fact, eliminates adverse, unintended effects. Neem is useful against gypsy moth, a pest which is causing severe damage to forests in parts of North America. Laboratory tests have shown that a very low concentration application of neem seed extract formulation, approved by the US Environmental Protection Agency, can kill gypsy moths. As mentioned above, neem products can influence about 400-500 insect species. So far we have concentrated on the effects of neem products on some of the important insects, which cause severe damage to crops and animals. As can be seen from the discussion above, it is now established that neem and its products are highly effective against many pestiferous insects. METHODS OF PREPARATION OF NEEM EXTRACTS Neem is attracting world wide attention in recent decades mainly due to its bioactive ingredients that find increasing use in modern crop and grain protection. Described here are some easy methods by which the Neem extracts can be prepared by the farmer himself:
The whole neem tree contains bitters in varied extent, but higher concentration of it is found in the neem kernel. Neem kernel is a valuable sousce of major limnoids responsible for pest contol. Hence good qulity of neem fruit is essential for production of high quality neem extract. It is therefore essential to understand the scientific method of fruit colletion and depulping.
NEEM FRUIT COLLECTION AND DEPULPING
Neem Fruit Collection
The neem yields fruits during May to August every year. The ripend fruits to be collected for the processing. Cover the ground below neem tree with cotton or jute cloth, or shade net to avoid contact of neem fuits with soil. It will also facilitate the collection of the furits. Being rich in carbohydreates neem fruits gets attacked by fungi when came in contact with soil. Such fruits may get infected with toxin developing fungus and may damage the qulity of the final products prepared from these fuits. Hence it is strongly recommended to avoid contact of neem fruits with soil. As the fruit ripes during rainy season they must depulped as early as possible. Avoid storage of fresh, wet fuits in the plastic bags. Use bamboo baskets or jute bags for storage.
Depulping of Neem Fruits
Depulping is a process to remove seed coat and pulp form the neem seed. It is done by hand and using mechanical depulper. Rub the ripe neem fruits between palms in the bucket of water and wash the seed. Use clean water for depulping. Neem Research and Technology Development Centre (NRTDC) developed a mechnical depulper to handle large quantity of neem fruits. After depulping and cleaning dry the neem seed in the shade in a thin layer. Select the place with good airation.Do not make heap of the seed. Protect it form direct rains. After drying neem seed upto 11% moisture store it in a jute gunny bags or bamboo baskets. Do not store in plastic bags as it may damage the quality of seed. Keep the neem seed in a cool and dry place. If processed properly these neem seeds can be stroed for 6-12 months. It is recommended to use neem seed for prepariton of extract or oil extraction after 3 months and before 8 months. The highest concentration of limnoids and oil found after 3 month and before 8 months period. Neem Kernel Aqueous Extract:
The simple method of Neem Kernel Aqueous Extract prepartion consist of following steps –
Take dried neem seed. Decorticate (Removal of seed coat ) it with the help of mortar and pastle or any mechnical decorticator. Clean the neem kernel and seed coat mixture by winnowing seed coat.
Weigh 1 kg of clean neem kernel and make powder of grain size like fine tea powder. It should be pounded in such a way that no oil comes out. Soak it in a about 10 lits of clean water. Add 10 ml of pH neutal adjuvant (mixture of emulsifier, spreader etc.) and stir the mixture. Keep the mixture overnight and filter it on the next day with clean muslin cloth. Put water in the residue and repeat the extraction 2-3 times. Use residue as a manure for plants. Spraying of NKAE
The spraying of 1.25% to 5% (Neem Kernel wt. Basis) of NKAE is recommended on the crops. The use of is recommended as a preventive at lower concentrartion and protective at higher concentaton i.e. uptp 5 %. Use the spray solution on the same day. Spraying should be done in the low intensity of sunlight preferablery in the afternoon. The effect of the NKAE remains for 7-10 days. Care to be taken to cover all plant foliage with NKAE. Neem Leaf Extract:
For 5 litres of water, 1 kg of green neem leaf is required. Since the quantity of leaves required for preparation of this extract is quite high (nearly 80 kg are required for 1 hectare) this can be used for nursery and kitchen gardens. The leaves are soaked overnight in water. The next day the leaves are grounds and the extract is filtered. The extract is beneficial against leaf eating caterpillars, grubs, locusts and grasshoppers. To the extract, emulsifier is added as mentioned in kernel extract.
Neem Cake Extract:
100 gms of Neem cake is required for 1 litre of water. The Neem cake is put in a muslin pouch and soaked in water. It is soaked overnight before use in the morning. It is then filtered and emulsifier is added -1-ml for 1-litre of water. It can then be used for spraying.
Neem Oil Spray:
15-30 ml Neem oil is added to 1 litre of water and stirred well. To this emulsifier is added (1ml/1litre). It is very essential to add the emulsifier and mix properly. This should be used immediately before the oil droplets start floating. A knapsack sprayer is better for Neem oil spraying in preference to a hand sprayer.
Precatutions for using Neem Extracts/Formulations :
Spraying should be undertaken in the morning or late in the afternoon. Insects lay eggs on the underside of the leaves. Hence it is important to spray on the underside of the leaves as well.
Caution
The active principles of Neem are destroyed by
• Heating and boiling the extract- do not boil the mixture
• Acidic or alkaline pH emulsifier- use neutral pH emulsifier
• Ultraviole rays of sulight – Spry during moderate sulight,
• Hydrolysis of water- use aquous extract on same day
NEEM AGAINST NON-INSECT PESTS Research in recent years has shown that neem is quite effective against non-insect pests also. Threadworms are among the most devastating agriculture pests. These nematodes are very difficult to control. Use of synthetic nematicides is not desirable as they cause toxicological effects. Research has shown that these pests are susceptible to neem products. Certain limonoid fractions extracted from neem kernels are providing active protection / defence against root-knot nematodes’. Water extracts of neem cake are also nematicidal. Neem cake is already being used on commercial basis by cardamom farmers in south India.
Fungi attack plants and trees in numerous ways and forms. They cause massive damage to important crops such as wheat, rice and corn. Several tests have demonstrated that neem acts as a fungicide. Should this prove widely applicable, it would have enormous positive effects on agriculture, environment and food supply with highly valuable effects like reducing poverty, increasing production etc. on a global scale. Some tests have shown unusual and promising results neem-leaf extracts failed to kill the fungus Aspergillus flavus but completely stopped it from producing aflatoxin’. This is important because aflatoxin is a powerful carcinogen that is causing increasing concern regarding the world’s food supplies.
FOR PROTECTING STORED GRAINS One of the traditional uses of neem in Asia has been for controlling pests of stored products. Farmers usually mix neem leaves with grain before keeping it in storage for several months. Neem leaves, oil or extracts acts as repellent against several insects such as weevils, flour beetles, bean-seed beetles and potato moths. Treatment of jute sack by neem oil or azadirachtin-rich-products prevents the penetration of pest like weevils and flour beetles. Neem oil destroys bean-seed beetles (bruchids) – a variety of insects mostly attacking legumes – at the egg-stage itself. A mixture of neem leaves with clay and cow-dung develops pest resistant property so it can be used to make bins for storage of grain.
Postharvest losses are notoriously high in developing countries. Worldwide annual losses in store reach up to 10% of all stored grain, i.e. 13 million tons of grain lost due to insects or 100 million tons to failure to store properly.
While neem treatments cannot replace completely chemical pesticides used in stored products preservation, the amounts of pesticides needed could be reduced, thereby decreasing the pesticide load in food grains. With proper timing and innovative methods of application, their use could be integrated in stored products management.
NEEM FOR SOIL FERTILITY & FERTILIZER MANAGEMENT Indian farmers have traditionally used deoiled Neem cake as a fertilizer in their fields. The dual activity of Neem cake as fertilizer and pest repellent, has made it a favoured input.Neem leaves have also been used to enrich the soil. Together, they are widely used in India to fertilize cash crops. When Neem cake is ploughed into the soil it also protects plant roots from nematodes and white ants. Farmers in southern parts of India puddle neem leaves into flooded rice fields before the rice seedlings are transplanted.
Table 4 :- Nutrient contents of Neem Seed Cake | CONTENTS | PER CENT | | Nitrogen | 3.56 | | Phosphorous | 0.83 | | Potassium | 1.67 | | Calcium | 0.77 | | Magnesium | 0.75 | Source : Neem A user's manual
Application to the Neem seed cake to crops provides them with various nutrients. Besides the Neem seed cake also reduces the number of soil insect pests, fungi, bacteria and nematodes and protects the crop from damage caused by these organisms. Neem seed cake can also reduce alkalinity in the soil by producing organic acids when mixed with the soil.
For cash crops such as tumeric, sugarcane, banana and cardamom, 200 kg per hectare of Neem cake is applied. For black pepper and betelvine 250 g per plant is applied. Neem cake is also extensively used for citrus trees, jasmine, roses and vegetable crops as an organic manure.
Nitrogen leaching not only depletes precious nitrate but also takes away clay, soil, and organic matter, leading to low chemical soil fertility and low plant-available water reserves. Ammonia volatilization also can contribute to a nearly 60% nitrate loss. Loss through volatilization occurs when the denitrifying bacteria reduce the nitrate to elemental nitrogen and nitrous oxide which escape to the stratosphere and cause ozone depletion and also contribute to greenhouse warming. On the other hand, nitrate build-up in drinking water can reduce the blood's ability to transport oxygen, especially if the nitrates are converted into nitrites (blue-baby syndrome). Even ruminants are vulnerable to nitrate or nitrite poisoning, leading to poor growth rates, reduced milk production, and increased susceptibility to infections, and even abortions. Ammonia volatilization, urea hydrolysis, and leaching, were all reduced when urea was blended or coated with neem cake.
Results from several field experiments show that neem cake coating of prilled urea increased nitrogen uptake by 4.5 to 19.4%. The increase in rice yield due to neem cake coating/blending of prilled urea ranged from 1 to 54%, the average being 9.6%. Neem cake coated urea applied to rice or sugarcane also left a carryover effect and increased sugarcane yield by 7% in the ratoon sugarcane crop .
Ready-to-use, neem-based urea-coating agents, such as 'Nimin' (containing ca. 5% neem bitter tetranortriterpenoids) are now commercially available in India. Application of Nimin-coated urea (1 part Nimin: 100 parts urea, wt/wt) reduced losses of fertiliser N through leaching and denitrification by 30-35% and increased yields in treated crops by up to 25% (Vyas et al. 1996). The bitters in Nimin delay the denitrification process up to 30 d by either killing nitrifying bacteria or suppressing their activity. Coating urea with Nimin could bring a saving of up to 20% of urea. The technology is becoming popular with farmers in India where annual Nimin sales are now ca. 700 metric tons.
Neem for Sustainable Agriculture and Environmental Conservation
In the past two decades, "green revolution technologies" have more than doubled the yield potential of rice and wheat, especially in Asia. These high-input production systems requiring massive quantities of fertilisers, pesticides, irrigation, and machines, however, disregard the ecological integrity of land, forests, and water resources, endanger the flora and fauna, and cannot be sustained over generations. Also, we cannot look to the sea in future as fishing stocks in many parts of the world are already in crisis due to overfishing or pollution. To a great extent, future food security and economic independence of developing countries would depend on improving the productivity of biophysical resources through the application of sustainable production methods, by improving tolerance of crops to adverse environmental conditions, and by reducing crop and post-harvest losses caused by pests and diseases.
Industrial and other uses The neem can form the basis for manufacture of various consumer and industrial products. Properly dried decorticated neem seed yields seed coat and neem kernel. The seed coat is rich in lignin, cellulose etc. and can be used as a low calorific value fuel in brick kilns etc. As it has good mechanical strength it may be incorporated with wood shavings used for making particle-boards for thermal insulation by mixing with a synthetic resin like phenol formaldehyde, as adhesive.
The neem seed coat after powdering could be mixed with other unwanted organic materials of the industry like discarded neem oil residue or other agricultural wastes and pressed to form briquettes with the help of a machine. These briquettes can be used as fuel in boilers for steam generation.
For isolation of Azadirachtin by solvent process the kernel is powdered to a specific particle size. When the kernel is extracted with solvents, liminoids other constituents and the neem oil get dissolved in it, leaving the seed cake without the actives. The solvent from this mixture can be recovered by distillation. For bio-pesticide formulation, the actives are removed from the oil by using other solvents and the standardized extracts may be used for the formulating commercial products. The fatty residue obtained may be used in the manufacture of soap. The soap manufactured from this oil can be useful in treating skin problems.
In cold mechanical process, the neem seed kernels are subjected to mechanical pressing only and no chemicals, solvents or heat is used. This results in production of oil that is rich in liminoids, however the yield is low. This cold pressed oil may be further enriched by Azadirachtin and other actives obtained from solvent extraction for bio-pesticide formulations. It can also be incorporated in other oils or in cream or paste bases to manufacture skin ointments, mosquito repellent products etc. The deoiled cake obtained after solvent extraction has a small amount of oil and liminoids and after washing with water can be incorporated into poultry and cattle field. The residue cake may be used as a denitrifying agent or as a manure.
Neem and Environment In Indian culture Neem has been referred to as an air purifier and has been traditionally planted either in the backyard or beside the house. Recent scientific studies have indicated that the Neem tree has the capacity to absorb environmental pollutants and act as an air freshener by releasing oxygen and mild odorous principles. In a study done in 1996 by the scientists of National Environmental Engineering Research Institute, Nagpur, India, it was found that sites with Neem as a dominant species have higher SPI (Sink Potential Index). The data also proved that the Neem tree is one of the most suitable species for checking urban pollution in the industrial locations and it has potential in green belt development in hot spots with known history of high air pollution. Socio-economic benefits of Neem Neem plantation provides income by collection of neem fruits in rural areas as demand of neem fruits is increasing day by day. Neem can save crop protection expenses to large extent thus may help to increase profit in agricultue. Neem processing technologies like prepartion of neem seed powder, neem aquous extracts, neem oil and neem cake will create large employment in the rural areas. Use of neem in agriculture can reduce the load of poisionous chemicals in the environment as toxication by these pesticides may cause serious health hazards having impact on the working efficiency and financial condition of the farmers.
About Neem Foundation A NGO established in 1993 to help realize the full potential of neem for the benefit of the people of the world. It is apex body of all Neem movement world wide and promoting global awareness about Neem and other botanicals. Neem Foundation has its head office in Mumbai, established a Neem Research and Technology Development Centre (NRTDC), located in central India at village Gondkhairy, Th. –Kalmeshwar, Dist:- Nagpur. The centre aims to provide information, training on the utilization of neem in agriculture to the farmers. NRTDC also help farmers to develop organic farm and generate awareness about organic food among the consumers.
Our address for communication – Neem Foundation, 67-A, Vithalnagar Society, Road # 12 NS, Juhu Scheme Mumbai – 400 049, India.Tel: 2620 6367 / 2620 7867 Fax: 2620 7508
Email:
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Website: www.neemfoundation.org
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Dr. Kamal Nayan Kabra, Development & Ecological Role of Neem in India, Neem Foundation, India. 2000
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