WHAT IS SO SPECIAL ABOUT THE NEEM TREE? WHAT DOES IT DO?
The neem tree is native to tropical South-East
Asia where it is recognized as an important medicinal plant. As it grows quickly
and is extremely drought resistant, it has been cultivated for a long time in
the arid zones of Asia, Africa and Central America as a source of timber. In
India and Sri Lanka, its seeds and leaves are used for store pest control and
oil is extracted from the seeds for the production of soap. Both the cold
pressed neem oil and the oil-free part of the seed kernel can be used for pest
control. The leaves of the neem tree also contain insecticidal and repellent
substances although in much lower concentrations.
HOW TO PLANT NEEM TREES?
The seeds should be as fresh as possible as
older seeds often do not germinate. Provided that only a few trees are to be
planted, and there is sufficient moisture available, with minimum weeds, the
seeds may be sown directly into the ground. Two to three seeds are placed
together about 1 cm deep in loose soil. After germination, only the strongest
plant should be retained. When planting a large number, it is advisable to
cultivate young plants first in pots, trays or plastic bags. After 3 months,
they should be transplanted into the ground. When using bags or pots care should
be taken that the plants are not allowed to develop to a stage where the tap
root has pierced the bottom and has to be shortened before transplantation. This
weakens the trees and substantially slows their growth. (
HARVESTING NEEM SEEDS SCIENTIFICALLY?
Neem trees bloom for the first time when they
have reached the age of 2 to 3 years, and bear fruit at the age of 3 to 4 years.
They normally produce fruit once a year, but in some moist zones twice a year.
The fruit of the neem can either be shaken off the tree, picked, or stripped
from the branches. When ripe it is yellow in colour, about 2 cm in length and
oval-shaped. In the soft, sweet fruit there is a light-coloured seed of about
1.5 cm in length, containing one, or sometimes two, brown seed kernels. After
harvesting the fruit the ripe pulp should be removed as quickly as possible. In
some regions, birds or fruit bats eat the sweet pulp, so that a lot of clean
seeds can be found on the ground.
HOW TO DRY THE NEEM SEEDS FOR LATER USE?
In order to dry the seeds, they are spread out
for a few days on a solid and dry ground in the sun. The layer of seeds should
be as thin as possible, as when drying grain, legumes, coffee or cocoa beans.
The drying process must be carried out very carefully as undried seeds can
become mouldy quickly. During the rainy season the seeds to be dried should be
promptly covered over or brought indoors before rain showers begin.
APPROPRIATE METHOD FOR STORING NEEM SEEDS?
As the dried sees can also become mouldy during
storage, they should only be stored in airy containers (e.g. jute sacks or
baskets). Airtight containers such as plastic bags or pots are unsuitable.(
PROCESSING NEEM SEEDS?
To produce a spraying mixture with 10 ltrs of
water, 500 gms neem seeds are required. If it is not possible to weigh the
seeds, containers, such as traditional measuring tins and pots etc., where the
capacity is known, are equally suitable for measuring the correct amount of
seeds and water.
Before mixing, the seeds are crushed or pounded
preferably in a mill or mortar, then the crushed seeds are poured into the water
and stirred vigorously.
This mixture should now be left to stand for
atleast 5 hours – if possible overnight – in order that the neem substances are
fully released from the seeds into the water solution.
WHICH TYPES OF CROPS ARE BEST SUITED FOR TREATMENT WITH
NEEM INSECTICIDES?
Neem extracts are particularly suitable for use
on vegetables and small scale field crops. If sufficient water and sprayers are
available it is also possible to treat larger fields.
HOW DOES NEEM WORK, WHAT IS THE MODE OF ACTION AND HOW DOES
IT AFFECT INSECTS?
Numerous insect species are repelled by active
ingredients in the neem seed. As they find the taste and smell unpleasant they
avoid the plants that have been treated with neem extracts. Other insects die
some time after having eaten leaves or other parts of the plant treated with
these substances. They alter the behaviour in some insects or reduce their
ability to lay eggs. Other pest species are affected minimally or not at all by
the neem substances, probably as a result of their hidden biology.
HOW IS THE NEEM INSECTICIDE APPLIED TO THE PLANTS?
The neem extract can be applied in two ways:
When using a sprayer, the rough particles must first be filtered out of the
mixture to prevent clogging the nozzle. This is done by covering a bucket or
similar container with a coarse cloth or gauze through which the mixture is
poured. The sprayer is filled with the filtered solution and spraying of the
vegetable crops can begin.
If no sprayer is available the extract may be
applied with a straw brush. In this case, it need not be filtered. A brush made
with fine, flexible straw is simply dipped into the solution and shaken over the
plants until all the leaves are moistened. The effect of the neem substance
lasts between 3 to 6 days, regardless of how it was applied.
HOW OFTEN DOES NEEM HAVE TO BE APPLIED?
If and when spraying is necessary depends very
much on the individual case and this can only be decided by the farmers or the
appointed adviser. In general, it may be said that in areas of vegetable
cultivation, where pests are a great problem, weekly spraying is necessary. If,
on the other hand, infestation is only slight, treatments in intervals of 10 to
14 days are adequate. Often a single treatment of the plants is sufficient. Just
as with chemical insecticides, the insect species and crop are important factors
in deciding how often spraying should occur. According to scientific research
the extract is not poisonous for humans, thus, it is not necessary to wait long
between final spraying and harvesting.
WHICH PESTS CAN BE CONTROLLED WITH NEEM?
The neem extract does not have the same effect
on all insect species. Some pest groups can be easily controlled. The feeding
behaviour of other groups may be influenced or their ability to reproduce
impaired, but this does not prevent direct damage to the plants. Some insects
react minimally or not at all to the extracts.
Given below you will find
more detailed information on the reactions of pests of neem extracts. It is
important to note, however, that this is not intended as a precise description
of the effects of neem extracts but as a guide which gives the user advice as to
which pests may be controlled by application of neem.
HOW CAN NEEM POWDER HELP TO CONTROL STEM BORERS ON YOUNG
PLANTS?
Stem borers on young corn and sorghum plants
can be controlled relatively easily with crushed neem seeds (the powder normally
used to mix with water). A small amount of powder mixed with sawdust or dry clay
at a ration of 1:1 is placed in the funnel. 1 kg powder should be sufficient for
1500 - 2000 plants.
In this method, rainwater dissolves the substances in
the neem seeds as it gathers in the funnel and washes out the powder. Where
rainfall is irregular a liquid neem seed extract can be sprayed into the
funnel.
This treatment should be repeated every 8 to 10 days during the
sensitive growing phase. Thus, roughly three treatments are sufficient for
protection against stem borers. This recommendation applies only for young
plants before flowering and not for older plants.
WHAT IS THE ROLE OF NEEM IN GRAIN STORAGE?
Stored grain legumes can easily be infested
with bruchids. These are small beetles whose larvae eat into the grain. The
bruchids can be controlled simply by mixing the legumes with neem
oil.
Neem oil is extracted from the neem seed kernels (oil content 40 –
50%). When used for storage protection it should be carefully pressed, either by
machine or various other traditional methods. As only a very small amount of oil
(30 ml oil per 100 kg grain) is required, pressing by hand is practicable. The
seeds must first be shelled, by cracking the shells with a stone or gently
pounding in a mortar and finally by winnowing to remove the shell
particles.
If the crushed seeds are very hard and brittle they should be
moistened and left to stand for several hours until they can be pressed together
by hand. Crushing the seeds in a mill or mortar produces a rough, sticky mixture
out of which can be pressed by kneading. Usually it is necessary to add a little
water to make kneading easier.
By alternating kneading and pressing of
the paste in a bowl the neem oil is released. Using this method it is possible
to extract 150 ml oil from 1 kg powder. The legume seeds are treated with neem
oil extracted in the following manner: The appropriate amount of neem oil is
mixed with the legume seeds in a large bowl or similar container (3 ml per 1 kg
grain); then the seeds may be stored in the usual way.
Neem oil is
non-poisonous but very bitter, thus freshly treated legumes taste at first very
sharp. This taste disappears, however, after 3 to 4 weeks.
WHAT OTHER USES ARE THERE FOR NEEM OIL?
Apart from its previously described application
for storage protection, neem oil has been a trusted remedy for a naturally
healthy skin in the villages of India. Derived from the seeds of the neem tree
it contains all the disinfecting and healing properties of the tree, in a
concentrated easily usable form. For centuries, this therapeutic oil has
provided protection and
Scientific studies have shown that Neem contains
certain chemicals, which are unique. The primary chemicals are a mixture of 3-4
related compounds called limonoids. Neem seeds also contain a few chemicals that
have sulphur. These phyto-chemicals add the characteristic smell to the neem
oil. They also attach additional curative properties to the oil. It has a dark
yellow color, turns solid at temperatures below twenty-three degrees Celsius,
and does not dry out. The oil is composed mainly of glycerides of palmitin,
stearin, oil and linol acids. It chemically resembles soy oil or olive oil. In
the cold-pressed oil, there are also 10 to 20 percent of the total content of
biologically active components, especially the limonoids. Bitter components
contained in neem oil and certain sulfur compounds that give the oil its strong
garlic scent, destroy the taste.
It is a completely natural total first
aid tool for families. Due to its unique composition it has an almost magical
effect on chronic skin conditions that fail to respond to conventional
treatments. What makes neem oil outstanding in comparison to other remedies is
that it is active against all three varieties of infectious organisms: Bacteria,
Fungii and Viruses. The oil is known to provide a very effective germicidal
action. Modern science has now confirmed the effectiveness of Neem oil in
fighting infection. Scientific studies indicate that Neem has very powerful skin
rejuvenating qualities and it is being hailed as the Oil of Wonder.
Many
strains of bacteria are found to be resistant to the modern antibiotics. Neem
oil has a seemingly endless range of antibacterial uses. This has prompted the
development of neem as an anti-bacterial drug for these resistant strains,
against which it has shown promising activity in the laboratory tests. Because
of its antiseptic qualities, neem oil is also well suited for medicinal soaps
and pharmaceuticals such as salves and creams. Neem oil is used in cosmetics for
creams, lotions and shampoos.
It has a wide spectrum of action and can be
safely used for a variety of skin conditions. Neem oil and many of its
constituents have been successfully used against a wide range of bacteria,
viruses, fungi and parasites. Neem oil has been reported to be effective against
certain human fungi, which are even difficult to control, by modern synthetic
fungicides. These include some Trichophyton, Epidermophyton, Microsporum,
Trichosporon, Geotricum and Candida. Neem oil inhibited the growth of all the
three strains of Mycobacterium in a concentration of 12.5 mg/ml.
Neem
oil has consistently shown moderate to potent anti-bacterial activity against a
wide range of Gram positive and Gram negative microorganism. The oil possess
marked spectrum of anti-bacterial activity against Gram negative and positive
microorganisms including M. tuberculosis, streptomycin resistant strain. Neem
oil absorbs quickly into the skin and has good skin penetration. It’s compounds
are non-irritating and are known to have a minimum of allergic reactions. It is
neither too hot (ushna) nor too cold (sheetha) in potency (veerya) and subsides
pitta and kapha dosha, promoting holistic health for mind, body and
spirit.
If you are looking for a natural remedy for skin irritations,
pure medicinal grade Neem oil could well be your answer.
IN WHAT OTHER WAYS CAN THE NEEM TREE BE USED?
Apart from its suitability to provide shade and
for Afforestation the wood of the neem tree is very much in demand. The trunk
and branches are ideal for building being both strong and rather resistant to
termites. It is also used for firewood and in the making of
charcoal.
There is an important point to remember when using neem for
firewood: If, as is common practice in many countries, the branches and the top
of the tree are regularly pruned, it will be some time before the trees again
produce fruit as they will first try to re-establish branches. Thus the combined
use of the neem tree for insecticide and firewood is only possible when the tree
is left undisturbed for several years. In other words: In order to produce
insecticide, the original branches should be left intact (fruit production
begins in 3 – 4 years). Only trees that are at least 10 years old should be used
for firewood and only after the younger trees, planted later, have begun to
produce sufficient fruit.
SOME ADDITIONAL INFORMATION
The neem tree (Azadirachta indica A. Juss)
thrives almost anywhere in the tropical lowland, upto 800 m above sea level. It
is resistant to extreme drought and grows where the annual rainfall is as sparse
as 300 mm. Moreover, it grows very quickly and makes few demands on the soil
fertility. The neem tree, therefore, grows in a wide variety of places. Hilltops
and infertile, depleted land (e.g., Eroded hillsides) are as suitable as stony,
flat land or hard laterite. The neem tree may be used to line avenues, to border
roads or fields and in mixed cultivation with fruit trees. The average annual
fruit yield from a mature neem tree is above 20 kg. Apart from insecticides,
neem oil may be extracted from the seed. 30 kg neem seeds produce 6 – 8 kg oil.
The resulting residue can be used to make insecticides in a similar way as from
the whole neem seeds described earlier.
All parts of the neem tree can be
utilized. Insecticidal substances are present in various parts of the tree; the
highest concentrations are, however, contained in the
seeds.
Azadirachtin, the most important insecticidal substance contained
the plant, has, even in very small doses, a growth disrupting effect on many
insect larvae, i.e. insects which eat this substance are unable to develop to
the next larval / nymphal stage and die off. Other pests, such as grasshoppers,
avoid or reduce feeding as a reaction to azadirachtin. As tests have repeatedly
confirmed, due to its special mode of action, the neem extract is quite harmless
for useful insects. Unlike synthetic pesticides, tests carried out over a longer
period indicate that development of any resistance to the neem extract is in the
short term unprobable. However, where intensive vegetable cultivation is
practiced, the exclusive use of neem extract is inadvisable.
One great
advantage of the neem extract is that even after repeated application on
vegetable crops, it remains perfectly harmless for humans.
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