NEEM: Use as Insecticide
BY M. DREYER & ECHO STAFF,
INSTITUT FUR PHYTOPATHOLOGIE UND ANGEWANDTE ZOOLOGIE,
JUSTUS-LIEBIG UNIVERSITAT, GERMANY
Published 1984
This technical note was published in the early 80's when there were
relatively few sources of information on, or seed for the the neem tree.
In recent years much progress has been made in each of these areas. The
information contained in this technical note is still quite valuable. A
good source of additional information is the National Academy of Sciences
publication Neem: A tree for Solving Global Problems. Like all NAS
publications, it should be available from: BOSTID Publications - HA 476,
2101 Constitution Avenue N. W., Washington, D.C. 20418. Complementary
copies are sometimes provided free-of-charge to those working with Third
World development organizations (use official letterhead and titles). ECHO
now has it available for sale for $19.00 plus $2.00 postage in U.S.A.
The following recommendations are based on our own experience,
scientific publications, two conferences on neem and personal
communication. We would like to give some brief and practical
information; for details and scientific background we refer to the
selected literature in the appendix. Please note that we cannot
accept any liability for the practicability and effectiveness of the
recommended measures.
INTRODUCTION
The neem tree (Azadirachta indica Juss.) probably originated in
India or Burma, where its medical and insecticidal properties
are well known. Furthermore, neem oil is used on a small industrial
scale for soap production. At the beginning of this century the neem tree
was introduced to many other tropical countries, especially in Africa.
Here, many of its properties are still unknown and it is mostly used for
firewood and as a shade tree.
Recalling the insecticidal properties of neem, researchers began
programs in the early sixties to identify the active principles and to
screen insect species against which they can work. The results to
date indicate that there are several active compounds, which are mostly
concentrated in the seeds. Some of them inhibit larval development
and reduce female fertility in various insect species by blocking insect
hormones. Others act as repellents or antifeedants. The
compounds are most effective against insects of the following families:
Coleoptera (beetles and their larvae), Lepidoptera (caterpillars = larvae
of butterflies and moths), Orthoptera (nymphs and adults of grasshoppers
and locusts). Results against some bugs, leafhoppers and whiteflies
have also been good.
HARVEST AND PROCESSING
In many areas seeds are easy to collect from the ground because birds
or fruit bats eat the juicy and sweet fruits and spit out the kernels.
Where this does not occur, the harvested ripe fruits need to be pulped.
If water is available the risk of infection by fungi can be reduced by
washing the grains after collecting them. For further processing
(oil, water extracts) and the storage the kernels should be well dried.
By spreading these on a hard ground in the sun. To avoid moulding,
kernels should always be stored in a well aerated recipient such as a jute
sack. Never store them in a plastic bag. Moulding can be due
to aflatoxin producing fungi, a substance which is highly toxic to human
beings even in low concentrations. To prepare seeds for planting dry them
carefully, if possible in the shade, because temperatures above 45oC
will reduce germination. Storage for more than one month will also
decrease the rate of gernimation. For immediate sowing kernels do
not have to be dried.
OIL PRODUCTION
To press neem oil by hand, the kernels have to be decorticated.
To do this, take stones or a big mortar (as used for "fufu" in
West Africa) to crush the kernels. Then remove the shells by
winnowing, as is traditionally done with cereals. The
decorticated kernels must now be ground in a mill or pounded in a mortar.
The powder thus obtained should be moistened with a little bit of water
(attention: do not add too much) until it sticks together and
an almost solid ball can be formed. Knead this paste for several
minutes until oil collects on the surface; then press it firmly. Oil
will come out in drops. Alternate the kneading and pressing.
In this way half the oil in the kernels, which could be l00-l50ml per kg,
can be gained. Do not be discouraged if you do not succeed at first.
Try it again, your results will improve with experience.
If you use an expeller oil press you do not need to decorticate the
neem seeds.
In many regions there are existing traditional methods of oil
production with other oil seeds (peanuts, sesame. etc.). Test these
with neem seeds and continue to use them if they are suitable; they will
be better accepted than newly introduced methods. Heating of
oil will not affect its insecticidal purpose.
PRACTICAL USES
| The neem tree is fast growing and
drought resistant. Therefore it is widely used to reforest
semiarid areas. |
| Neem seeds contain up to 45% oil,
which can be used for soap production or as fuel for lamps. |
| Neem seed cake (residues of oil
extraction), when used for soil amendment or added to urea or
ammonia containing fertilizer, not only enriches the soil with
organic matter but also lowers nitrogen losses by inhibiting
nitrification. In addition, some nematicidal properties have
been reported. |
| Neem oil - at a concentration of
2-4ml/kg - can protect stored beans against the bruchid (Callosobruchus
maculatus), which is a worldwide serious storage pests
worldwide. Protection lasts for at least a period of six
months. Good results against pests of stored cereals (wheat,
maize, sorghum) were also obtained. |
| Water extracts of powdered neem
kernels can protect plants against damage done by several insect
species. |
| A tea prepared of leaves is used
traditionally to reduce fever caused by malaria, etc. This
tea is extremely bitter. |
USING NEEM OIL TO PROTECT BEANS AGAINST STORAGE PESTS
Take 2-4ml of oil per kg of threshed beans. Because only a small
amount of oil is needed, the beans and the oil have to be thoroughly
mixed. This is best done in a big pot or something similar, and the
beans are treated portion by portion.
Neem oil has a bitter taste. Nevertheless people did not report
any bitterness or difference in taste after they ate meals with neem oil
treated cowpeas. But if you want to avoid any chance of influence in
taste, soak the beans for about 5 minutes in hot water before further
preparation. No recommendation can yet be given for the use of neem
oil with stored cereals. Results reported so far have been
conflicting and were less promising as with beans. If you would like
to test it your self, treat the cereal in the same manner as beans.
WATER EXTRACT FOR PLANT PROTECTION
Start the extract preparation one day before application. For 1
liter of water, take 25g of ground neem kernels (=decorticated seeds) or
50g of ground neem seeds (not decorticated) and let the mixture stand
overnight (for grinding or pounding respectively see "Oil
Preparation"). Then filter the extract through fine gauze, a
fine meshed sieve or tissue to remove the bigger particles. The
extract can now be applied with a knapsack sprayer or a handpump sprayer.
You do not need any emulsion or wetting supporting substance.
The active compounds of neem are decomposed rapidly, especially under
tropical conditions. Therefore crops which are attacked consistently
have to be treated weekly; in the case of a serious locust or grasshopper
attack it is better to treat biweekly. If crops have to be watered
(vegetables), irrigate the soil directly. Water running over
the leaves may wash off the extract.
The author himself obtained good results in field trials conducted in
Togo against the main pests of cabbage (caterpillars), most of the main
pests of eggplant (caterpillars, plant hoppers, except spider mites), the
main pests of solanaceous vegetables (caterpillars) and important pests of
courgette (larvae of leaf eating beetles, whiteflies). Always remember
that neem will not act against every pest and that the best results will
be shown by insect species belonging to the families mentioned elsewhere
in this technical note.
ADDITIONAL USES FOR NEEM (FROM PAST EDN ISSUES)
MOSQUITO REPELLENT FROM NEEM
Dr. V. P. Sharma, Director of the Malaria Research Centre in New Delhi,
says the repellent is particularly effective against the Anopheles
mosquito which spreads malaria. When the preparation is applied to the
body, mosquitoes are effectively repelled. Low-cost neem oil is mixed with
coconut oil in concentrations of 1-2%. This information is taken from Neem
News, vol 1, p. 4, published by the Neem Association, 1511 Oneco Ave.,
Winter Park, FL 32789, USA. The non-profit association is organized to
promote communication between neem scientists, growers and producers;
promote its various uses and seek other uses; promote research to develop
superior varieties of neem and to develop new uses. Membership is US $20.
CONTROL OF SCABIES
Dr. S. X. Charles at the Medical and Cancer Research and Treatment
Center in India sent us the results of a study of 814 people treated with
neem and turmeric. (Scabies, also called seven year itch, is especially
common in children. It causes very itchy little bumps that can appear all
over the body, but are most common between fingers, on wrists, the waist
and genitals. It is caused by little animals similar to tiny ticks or
chiggers, which tunnel under the skin.)
Scabies is treated with a scrub bath, boiling the fomites (clothes and
bed linens), and application of a paste made by grinding "Fresh neem
leaves and turmeric in the proportion of 4:1 by weight. The measurement
that is taught to mothers is a handful of neem leaves and a piece of
turmeric * the length of the index finger. This paste is rubbed all over
the body and left to dry. The procedure is repeated daily until the
patient is cured. (Boiling clothes and scrub bath is carried out daily
before application of the paste.)
"Paste rubbed on the face has not caused any skin reaction or
other toxic symptoms. Because of the bitter taste, chances of children
swallowing it was remote, and even if swallowed [is not toxic]."
"Of the 824 cases, 98% showed complete cure within 3-15 days of
treatment. Those cases (95.8%) with localized lesions showed cure in 3-5
days. When lesions were all over the body and there was secondary
infection, treatment needed for a cure was 6-15 days. Failure of treatment
was only 2%. The reasons for failure were irregular application of paste
and not doing the preliminary treatment of scrub bath and boiling of
fomites to prevent reinfection."
CONTROL OF NEMATODES
"There is evidence that leachates from the litter of certain trees
and shrubs [Ed: water that has soaked through the litter] have nematicidal
properties, e. g. Azadirachta indica (neem), Ricinus communis
(castor bean) and Leucaena leucocephala." Farmers in Sao Luis
put 1 kg of neem leaves per square meter in the soil (25 cm deep) before
planting carrots in order to control soil nematodes.
NEEM LEAF TEA TO CONTROL TERMITES
We seldom hear of any natural control that works with termites. Don
Mansfield in Mali sent the following. "A Norwegian missionary here in
Mali told me how to control termite damage to trees with neem leaf tea (Azadirachta
indica). A barrel or bucket is filled with green neem leaves. They
cover the leaves with water and after 4 days use the liquid against
termites. I don't know whether it kills them or just keeps them away. The
missionaries swear it really works. (26-1)
"It has been a great success for me. Most of the time when I've
used it, it has been setting for at least 2 weeks. When I see where the
termites are starting up a tree or pole, I knock them and their clay off.
Then I take a paint brush and paint the whole area where the termites had
been on with the tea. I make sure that plenty runs down around the base.
Twice I have had to do it a second time after about a week, but all the
other times I have only done it once and the termites have not come back.
It has been 5 or 6 months since I treated a couple mango trees, which have
not been bothered since.
MORE USES OF NEEM AS AN INSECTICIDE
R. N. Mall in Pakistan writes, "We learned during the Health
Education Program that in some villages the seeds are crushed and the oil
is being used against head lice, which is quite effective."
Dick Lockman, also in Pakistan, says that they use the dried leaves for
moth protection of woolen clothing in storage. A few leaves in the
pockets and scattered among the items prevent moth damage. (10-5)
The following three paragraphs are abstracted from an article in the
magazine Baobab, #5, 1990. They in turn learned it from "The Farming
World" of BBC World Service. (35-1)
For the past 20 years, Professor Ahmed Sadiq has been working with the
use of neem in pest control. Recently CARE started trials in collaboration
with him. The seeds have about twice the potency of leaves, but seeds are
only available for 3-4 months each year. So they are working with leaves.
Leaves are dried in the shade, because the ultra-violet from the sun will
break down the active ingredient. When the leaves are dry, they are
crushed to a powder in a mortar and pestle. They can then be used directly
for dusting crops or as a powder in stored foods. The powder can also be
mixed with water and sprayed on crops.
Most farmers like to see pests drop dead right away. Neem does not have
this sort of effect, with a few exceptions. Its main effect is as a
repellent. If insects do eat the treated plant, the neem has a hormonal
and growth-regulator effect. Local farmers have used it only one year.
Those who treated okra with it said grasshoppers avoided treated plants.
Farmers who treated watermelon seeds with neem powder said that rats
that normally eat the seeds did not eat the treated seeds. Neem is not
usually thought of for rodent control, but it has a flavor which perhaps
the rats did not like.
NEEM SEED AS A FEED INGREDIENT
Four Nigerian scientists have shown that the ground seeds can replace
up to 28% of the corn and cotton seed meal in a rabbit ration. (33-7; from
"The Journal of Applied Rabbit Research," vol. 13, pp 125+126,
1990. )
Fresh neem fruits were soaked for one day, after which the pulp was
removed manually and discarded. The seeds were washed, dried several days,
then ground. The greatest daily gain was with 10% neem seed meal. The
authors speculate that the foul-smelling odor of neem seed meal and bitter
taste account for a lesser amount of feed eaten with the highest level of
neem.
Note that in these experiments the entire seed was ground. Many farmers
might prefer to extract the oil first. This would presumably remove some
of the bitter tasting substances. The extracted meal would contain a
higher percent of protein, but less energy. Without the oil, the extracted
neem seed would presumably more closely resemble the cotton seed meal
(meals have had the oil removed) than corn. I would speculate that it
could replace cotton seed meal or even soybean meal.
PRODUCTION RELATED TOPICS (FROM PAST EDN ISSUES)
SALT TOLERANCE OF NEEM
Neem (Azadirachta indica) seedlings have been grown successfully in
Pakistan on sandy soil using irrigation water with approximately 10,000
ppm salt. [Pure sea water is 35,000 ppm.] A neem plantation has been
established near Mecca in Saudi Arabia to provide shade for Muslim
pilgrims. Water with approximately 2500 ppm salt was used for irrigation.
NEEM AND BEES
Dave Morneau in the Central Plateau of Haiti asked us about the Haitian
beekeepers' belief that neem (Azadirachta indica) or chinaberry (Melia
azedarach) blossom nectar is harmful to honeybees, since leaves and
seeds are widely used to control insects. We checked ECHO's library and
found no written evidence to support this concern.
Neem: A Tree for Solving Global Problems reports that neem is
benign to most beneficial insects, and "[insects] that feed on nectar
or other insects rarely contact significant concentrations of neem
products." The authors cite a study which found that "only after
repeated spraying of highly concentrated neem products onto plants in
flower were worker bees at all affected. Under these extreme conditions,
the workers carried contaminated pollen or nectar to the hives and fed it
to the brood. Small hives then showed insect-growth-regulating effects;
however, medium-sized and large bee populations were unaffected."
DEVASTATING DISEASE OF NEEM TREES IN WEST AFRICA
We are suddenly hearing from many in our network about this disaster.
Mike Benge with USAID phoned to alert us to the problem and to say that
they were sending a team to investigate. Steve Maranz in Niger writes that
the neem disease has now reached all the way to Senegal. [ED: That's as
far west as one can go in Africa.] "It should be noted that to the
villagers here, none of the products and services rendered by neem compare
to its value as a shade tree. When there is nothing in the bare landscape
between you and the blazing sun, the thick shade of a neem is heavenly. So
much more the loss, then, when a 20 year old neem tree dies." On a
related note, Steve writes, "I saw that our cowpeas were infested
with beetles (I assume the bruchid beetles one reads about). I asked our
field technician if he had ever used neem oil to control these pests. His
answer was interesting. He said he knew it was effective, but would rather
lose half his cowpeas than have to taste neem in his food. This is from
someone who eats kola nuts every day, which are as bitter as
quinine."
PEFERENCES
Anonymous. (l982). Neem tree may be source of safe insecticides.
IRRI Reporter 82 (2)
Schmutterer, H. (l98l). Some properties of components of the neem
tree and their use in pest control in developing countries.
Med. Fac. Landbouww. Rijksuniv. Gent, 46/l
Schmutterer, H., Ascher, K.R.S., and Rembold, H. (l980). Natural
pesticides from the neem tree. Proceedings of the first neem
conference, published by the German Agency for Technical Cooperation (GTZ),
Eschborn, FRG
Warthen, J.D. Jr. (l979). Azadirachta indica: a source of
insect feeding inhibitors and growth regulators. Science and
Education Administration, Agricultural Reviews and Manuals, Northeastern
Series, No. 4, April l979 USDA, Beltsville, USA
Sources of Seed and Neem Products
When ECHO receives a request for neem seed ($5 per packet; free to
Third World development organizations), we hold the orders until either
our tree produces (which it does not do every year) or we obtain a fresh
shipment from overseas. For those passing through we often have seedlings
available in our nursery. We can also recommend the following as potential
sources of seed (seed are only available on a seasonable basis, as they
must be planted within 3-4 weeks of harvest.):
SEED
U.S.
Agricultural Research Service (ARS), US Department of Agriculture
(USDA), 13601 Old Cutler Road, Miami, FL 33158, (305) 238-9321.
The Banana Tree, 714 Northampton Street, Easton, PA 18042, (215)
253-9589.
The Kerr Center for Sustainable Agriculture, Vero Beach Research
Station, 7055 Cherry Lane, Vero Beach, FL 32966, (407)562-3802.
Robert Barnum, Possum Trot Nursery, 14955 S.W. 214th Street, Miami, FL
33187, (305) 251-5040.
AUSTRALIA. M.L. Farrar Pty. Limited, P.O. Box 1046, Bomaderry,
N.S.W. 2541, Australia.
ETHIOPIA. Forestry Research Center, P.O. Box 30708, Addis Ababa,
Ethiopia.
HONDURAS. Forest Tree Seed Bank, Apdo. Postal No. 2,
Siguatepeque, Honduras.
INDIA. State Forest Research Institute, Polipathar Jabalpur,
Madhya Pradesh PIN 482008, India.
Tosha Trading Company, 161, Indira Nagar Colony, P.O. New Forest,
Dehra Dun, U.P. 248006, India.
KENYA. Kenya Forestry Seed Centre, P.O. Box 20412, Nairobi,
Kenya.
MOZAMBIQUE. Centro de Experimentacao Florestal, Marracuene,
Mozambique. antonia@ribeiro.uem.mz
MALAWI. Forestry Research Institute of Malawi, P.O. Box 270,
Zomba, Malawi.
NICARAGUA. Centro de Mejoramiento Genetico de Semillas
Forestales, Aptdo 630, Leon, Nicaragua.
NIGERIA. Nathanael Ariyo Olonire, P.O. Box 2674, Sokoto,
Nigeria, West Africa (bulk neem seed, leaves etc.)
SINGAPORE. Inland & Foreign Trading Co., Block 79A, Indus
Road #04-418, Singapore 169589, Singapore. iftco@pacific.net.sg
TANZANIA. Tanzania Forestry Research Institute, P.O. Box 95,
Lushoto, Tanzania.
ZIMBABWE. Forestry Commission, Forest Research Centre, Tree Seed
Centre, P.O. Box HG, 595, Highlands, Harare, Zimbabwe. frchigh@harare.iafrica.com
SEEDLINGS
Saleem Ahmed, East-West Center, 1777 East-West Road, Honolulu, Hawaii
96848, USA, (808) 944-7111.
Robert Barnum, Possum Trot Nursery, 14955 S.W. 214th Street, Miami, FL
33187, (305) 251-5040.
John Conrick, Winter Park, Florida (407) 384-7616.
Chip Gardner, California, (209) 674-9543.
Pacific Tree Farms, 4301 Lynnwood Drive, Chula Vista, CA 92010, (619)
22?-2400, ($36 per plant, no seeds).
Marlin Huffman, Plantation Botanicals, Inc. PO Box 128, Felda, FL
33930, (813) 675-2984, fax: 675-4591, (top quality West African germplasm
from Larson, planted mid-1991).
Sandy Mush Herb Nursery, Route 2, Surrett Cove Road, Leicester, NC
28748, (704) 683-2014, (root cuttings).
EXTRACT
AgriDyne Technologies, Inc., 417 Wakara Way, Salt Lake City, Utah
84108, (801) 583-3500; fax 583-2945.
Ringer, Valley View Road, Eden Prairie, Minnesota 55344.
Jim Walter, W.R. Grace Washington Research Center, 7379 Route 32,
Columbiz, MD 20861, (410) 531-4000.
INFORMATION
The Neem Association, 1511 Oneco Avenue, Winter Park, FL 32789
Axel Bosselmann, POB 1166, Charters Towers, 4820 Queensland, AUSTRALIA
(publishes Neem Notes)
ECHO, 17391 Durrance Rd., North Ft. Myers FL 33917, USA
Phone: (941) 543-3246; Fax: (941) 543-5317
|