Modern Scientists have now identified Azadirachtin as the Key ingredient which is mainly responsible for the Pesticidal/ Larvicidal / Antifeedant, etc..action of Neem on various Insects & Pests.
Azadirachtin being the key molecule, more concentration on Research & developments have been targeted on Azadirachtin in India and abroad. However now it is clearly known that besides Azadirachtin, salannin, gedunin, azadirone, nimbin, nimbidine, nimbicidine, nimbinol, etc.. are also important liminoids which play excellent synergistic effects on Insects/Pests.
The Azadirachtin used for fortifying is of various technical grades ranging from 8 - 45 % to get the desired strength of Azadirachtin in the final formulation ranging from 300 ppm Azadirachtin to 60000 ppm.
NEEM: A POTENTIAL BIOPESTICIDE AND SOIL CONDITIONER : One of the most promising benefits of the neem tree may be the use of neem extractions in new organic insecticides. According to the World Health Organization, over 20,000 deaths and a million illnesses each year result from misuse or overuse of pesticides in the Third World alone Neem insecticides have many advantages over traditional chemical methods: research indicates they are not harmful to humans or animals, insects don't become resistant to them, neem extracts do not accumulate in the environment, and they also spare beneficial insects like butterflies and ladybugs. Most importantly development in recent years is the increasing Organic food industry in world market, Neem use in Agro industry is increasing and will boom in the next 10 years.
THE NEEM : In India Neem is a common sight as roadside tree bearing small, white and sweet scented flowers seen in India. Neem blossoms in early April in North Indian conditions. Neem tree is considered a good purifier of air, due to its large leaf area. Oilcake, obtained from seeds, is used as a fertilizer and manure. Azadirachtin, isolated from the tree, has been found to have insect repellent and insecticidal properties.
NEEM as Pesticide : NEEM P is widely used in several countries around the world today either singly in Integrated Pest Management or in conjunction with synthetic pesticides. NEEM P is the general- purpose botanical pesticide of choice for organic agriculture. NEEM P is superior amongst other botanical pesticides such as Rotenone and Pyrethrins, due to reasons cited below.
- Research has shown that neem extracts can influence nearly 200 spices of insects including pests are resistant to pesticides, or are inherently difficult to control with conventional pesticides; floral thrips, diamond back moth and several leaf miners.
- NEEM P belongs to the category of medium to broad spectrum pesticides.
- NEEM P works by intervening at several stages of the life of an insect. It does not kill the pests instantaneously but incapacitates it in several other ways.
|
Mode of Action : Neem as a biopesticide does not exhibit the knock out effect of chemical pesticides but affects pests in several ways.
Oviposition Deterrent Insect Growth Regulation : A very interesting property of neem products and unique in nature, as it works on juvenile hormone. The insect larva feeds when it grows, it sheds the old skin and again starts growing. This particular shedding of old skin is the phenomenon of ecdysis or moulting is governed by an enzyme ecdysone. When the neem components, especially Azadirachtin enter into the body of larvae, the activity of ecdysone is suppressed and the larva fails to moult, remains in the larval stage and ultimately dies. If the concentration of Azadirachtin is not sufficient, the larva manages to enter the pupal stage but dies at this stage and if the concentration is still less the adult emerging from the pupa is 100 % malformed, absolutely sterile.
Feeding Deterrent : The most important property of neem is feeding deterrence. When an insect larva sits on the leaf, the larva is hungry and it wants to feed on the leaf. This particular trigger of feeding is given through the maxillary glands give a trigger, peristalsis in the alimentary canal is speeded up, the larva feels hungry and its starts feeding on the surface of the leaf. When the leaf is treated with neem product, because of the presence of azadirachtin, salanin and melandriol there is an anti - peristalitic wave in the alimentary canal and this produces something similar to vomiting sensation in the insect. Because of this sensation the insect does not feed on the neem treated surface. Its ability to swallow is also blocked.
Oviposition Deterrent : Another way in which neem reduces pests is not by allowing the female to deposits eggs. This property is known as Oviposition deterrence, and comes in very handy when the seeds in storage are coated with neem Kernel powder and neem oil. The seeds or grains obtained from the market are already infested with some insects. Even these grains could be treated with neem seed kernel extract or neem oil; after this treatment the insects will not feed on them. There will be no further damage to the already damaged grains and at the same time when the female comes to the egg laying period of its life cycle, egg laying is prevented.
Other pesticidal activity includes of need include:
(1) The formation of chitin (exoskeleton) is also inhibited.
(2) Mating as well as sexual communication is disrupted.
(3) Larvae and adults of insects are repelled.
(4) Adults are sterilized.
(5) Larvae and adults are poisoned. Use of neem products does not give immediate results like chemical insecticides. Some patience is required after application of neem products.
Chemistry of Ingredients of Neem : Neem plants contain several thousands of chemical constituents. Of which terpenoids compounds are important and also found in all parts of the neem plant. The most active and well studied compound is Azadirachtin. However, in most traditional preparations of neem as pesticide or medicine a mixture of neem chemicals are present and provide the active principles. Several different kinds of azadirachtins (A to K) have been isolated, the most abundant of which is Azadirachtin - A. The neem terpenoids are present in all parts of the plant, in the living tissues. Recently, the site of synthesis and accumulation of the neem chemicals has been identified as secretory cells. Secretory cells are most abundant in the seed kernels. The secretory cells can be seen with iodine solution. Besides the terpenoids, neem also contains more than 20 sulphurous compounds responsible for the characteristic smell of crushed seeds and neem oil.
Toxicity : In toxicological studies carried out in the USA and Germany, different neem product were neither mutagenous nor cancerogenic, and they did not produce any skin irritations or organic alternations to mice and rates even at high concentrations. In another Canadian study, Neem was found to be harmless to Aquatic invertebrates and other non-target species.
Benefits :
- Neem Pesticide is a natural product, absolutely non toxic, 100% biodegradable and environment mentally friend.
- It is suited for mixing with other synthetic pesticide and in fact enhances their action.
- None or lesser quantity of synthetic pesticides need to be used, thereby reducing the environmental load.
- Several synthetic pesticides being single chemical compounds cause easy development of resistant species of pests. Neem consists of several compounds hence development of resistance is impossible.
- Neem does not destroy natural predators and parasites of pests thereby allowing these natural enemies to keep a check on the pest population.
- Neem also has systemic action and seedlings can absorb and accumulate the neem compounds to make the whole plant pest resistant.
- Neem has a broad spectrum of action active on more than 200 spices of pests.
- Neem is harmless to non target and beneficial organisms like pollinators, honey bees, mammals and other vertebrates.
NEEM U with Urea :
Urea is the major source of nitrogenous fertilizer used in Agriculture. It is estimated that out of the total quantity of urea applied to crops, about 50- 70% is lost in various forms, thereby reducing the availability of nitrogen to crops. There is an age old practice in India of blending neem cake with urea. When NEEM U is coated on urea, it forms a fine coating and protects the loss of Nitrogen by denitrification ensuring regulated continuous availability of nitrogen for a longer period, as per the requirement of crops.
Mode of Action: When uncoated urea is applied to the soil, the urea (Amide) nitrogen is rapidly converted to ammoniacal nitrogen and subsequently to nitrite and nitrate forms. Nitrogen in these forms, besides being absorbed by plants, is also rapidly lost from the soil due to leaching, run off, volatilization and denitrification. When NEEM UCA coated urea is applied to soil, the neem triterpenes inhibit the activity of nitrifying bacteria resulting in delayed transformation of ammoniacal nitrogen into nitrite nitrogen. This ensures slow and continuous availability of nitrogen matching the requirements of crop plant during their life cycle.
Benefits:
(1) Ready to use, economical and easy to apply.
(2) Ensures slow and continuous availability of nitrogen to crops.
(3) Reduces nitrogen loss from urea due to leaching and denitrification.
(4) Protects crops from soil borne pests.
Method of Application:
(1) Spread 50 Kg urea in the shade on a clean surface.
(2) Mix evenly 250 gm NEEM U ensuring proper spreading on urea.
(3) Rub NEEM U to Urea thoroughly by hand to get a uniform coating. For larger quantities of urea, suitable mixers can be used.
(4) Allow coated urea to dry till it is free flowing and ready to use. |
|
No comments:
Post a Comment