Keeping Up with Neem PDF Print E-mail
KEEPING  UP  WITH  NEEM:

NEEM - A BOON TO BIODYNAMIC FARMING

By: D. Vanathi and S. Rathika
Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore - 641003 T.N.

Neem is a native tree of India, a tropical tree especially suited to semi-arid conditions. Neem is a medium large tree having short, straight bole, furrowed, dark brown to gray bark, with dense rounded crown of pinnate leaves. It belongs to the family Meliaceae and is becoming increasingly popular for its insect repellant traits and unique properly in inhibiting the nitrification process in the soil. In India, Neem grows in the plains and in areas that reach an elevation of about 1850 m. Neem is tolerant to most soil types including dry, stony, shallow soils, lateritic crusts, highly leached sands and clays. With an extensive and deep root system, the hardy Neem can grow and flourish even in poor, marginal and leached soils. The neem tree flowers between February and May. The honey-scented white flowers, found in clusters are a good source of nectar for bees. Neem fruits are green drupes that turn golden yellow on ripening in the month of June, July and August in India.

UTILIZATION OF NEEM AND ITS PRODUCTS
* The termite resistant neem timber is used as building material and in making furniture and farm
implements
* The bark yields tannin and gum.
* The amber-hued gum is used as a dye in textiles and traditional medicines.
* Leaves are used as fodder and green manure.
* Neem derivatives such as Azadirachtin, nimbicidin and a host of other compounds are now used  
in medicines and commercial pesticides.
* Neem leaf extracts have also been proven effective against one of the world's most dangerous  
substances, aflatoxin.
* A light coating of neem oil protects stored food crops for up to twenty months from all types of
infestations with no loss of palatability.

INDIGENOUS USAGE
* Mixing of neem leaves (2-5%) with rice, wheat and other grains is even now practiced in some
parts of India and Pakistan.
* As early as 1930, neem cake was applied to rice and sugarcane fields against stem borers and
white ants.
* Innovative farmers in Karnataka and Tamil Nadu states in India even today "puddle" green twigs
and leaves of neem in rice nursery beds to produce robust seedlings and simultaneously ward-off
attack by early pests - leaf hoppers and whorl maggots.

BIOCHEMISTRY OF NEEM
The active constitutent of Neem is made up of about 40 different active compounds called Tetranortiperpenoids, or more specifically, liminoids. The main active ingredient of Neem is Azadirachtin, and tetranortriterpenoid. It exhibits anti-feedant, insect repellant and insect sterilization properties. It interferes with ecdysone, the key insect molting hormone and prevents larvae and pupae from completing the molting process. Unlike chemical insecticides, it works on the insect's hormonal system, not on the digestive or nervous system, and does not lead to development of resistance in future generation. A kind of complementary effect was obtained from Azadiarchtin thereby one component strengthens and increases the working of another.

USE OF NEEM IN AGRICULTURE
Powdered neem seed kernel mixed with paddy (1 - 2%) significantly reduced infestation and damage to grain during a 3 month storage period, the effectiveness capacity of jute bag (100 x 60cm), controlled 80% of the population of major insects and checked the damage to wheat for upto 6 months. In early tests of neem extracts, the desert locust, which is known for its voracious appetite, refused to eat any plants sprayed with neem & eventually starved to death surrounded by its favorite food. In several tests, spraying neem oil on plants prevented the outbreak of powdery mildew better than popular commercial pesticides.

Studies discovered that neem cake was richer in plant nutrients than manure, killed damaging nematodes, promoted larger populations of earthworms, helped to keep nitrogen in the soil, making available for the plants, and provided significant protection from insects. This combination of effects provides an almost ideal growing condition for the plants. Neem Seed Kernel Extract (NSKE) in laboratory studies against egg hatch ability and development of Diamond Black Moth was established. The eggs were dipped in freshly prepared NSKE for 10 seconds and incubated at room temperature. NSKE at 1,2,3 and 4% concentration caused 71.72 to 82.46% egg mortality. Application of neem cake @ 500 kg/ha, either alone or mixed with urea in paddy fields in southern India reduced the number of pupae of Culex tritaeniorhynchus, the vector of Japanese encephalitis, and also resulted in higher grain yield.

EFFECT ON BENEFICIAL ORGANISMS
Only insects that eat plants are affected by neem, leaving honeybees and other beneficial insects essentially unharmed. In areas sprayed with neem, the average size and number of earthworms is greater than in unsprayed areas. Birds and beneficial insects, which are not affected by neem, then feed on the remaining weakened pests and small number of remaining offsprings.

Source: Agrobios Vol. III, No. 4 Sept, 2004
NEEM  FOR  DISEASE  MANAGEMENT

By: V. Jayalakshmi, S. Venkatesan and K. Shanmugam
Tapioca and Castor Research Station, Yethapur - 636 119

PADDY
1. Tungro virus: NSKE 5% or neem oil 3%. Three sprays have to be given at 15 days interval.
2. Sheath blight (Acrocylindrium oryzae): NSKE 5% or neem oil 3% can be sprayed at the time of
grain emergence.
3. Blast (Pyricularia oryzae): Spraying of neem oil 3% is effective.
4. Sheath blight (Rhizoctonia solabi): Soil application of 150 kg of neem cake/ha.

GROUNDNUT
1. Rust (Puccinia arachidis): Application of neem oil 3%. The first spray should be given immediately
after noticing the symptoms and the second spray 15 days later.
2. Foot rot (Sclerotium rolfsii): Application of neem oil 1% is effective.

COCONUT
Ganoderma wilt (Ganoderma lucidum): Soil application of 5 kg neem cake / tree / year during the rainy season. The neem cake should be applied in the basin around the trunk of the coconut tree.

BLACK GRAM
1. Powdery mildew (Erysiphe polyconi): Two sprays with neem oil 3% starting first spray at the
initiation of the disease and second spray 15 days later.
2. Root rot (Macrophomina phaseolina): Soil application of neem cake @ 150 kg/ha.
3. Yellow mosaic virus: Application of neem oil 3% of effective.

ARECANUT
Ganoderma wilt (Ganoderma lucidum): Soil application of neem cake @ 2.0 kg/tree year is effective.

CHILLI
Chilli mosaic virus: Spraying of NSKE 5% is effective against the aphid vector.

TAPIOCA
Tuber rot disease (Phytophthora drechsleri): Soil application of neem cake @ 150 kg/ha at the time of last ploughing.


COTTON
Root rot disease (Rhizoctonia bataticola): Soil application of neem cake @ 150 kg/ha. at the time of last ploughing

BETELVINE
Wilt (Phytophthora parasitica var. piperina): Soil application of neem cake @ 75 kg/ha. in three split doses first at 15 days after lifting the vines and second and third dose at 40-45 days interval.

Source: Agrobios
Vol. III, No. 4 Sept, 2004


EXPERIENCES  WITH  THE  USE  OF  NEEM  IN  ORGANIC  AGRICULTURE  (SOME EXAMPLES)

By: Dr. Carsten Hellpap
Deutsche Gesellschaft for Technische Zusammenarbelt GmBH, P.O.B. 5180, D-65726 Eschborn, Germany

The potential for use of neem in organic agriculture is considerable. However, up to now the utilization is still small because neem is new to many organic farmers and also due to the restrictions of the European community. Nevertheless, there are already several interesting examples of use of neem products in organic farming (Kienzle et al, 1997; Baumgart et al, 1997). Two such examples are presented here from the point of view of the farmer.

In the first example neem was used in a citrus farm in Portugal. The farmer applies neem seeds, cake and oil. In the nursery young seedlings of citrus plants are reared in soil mixed with 3% cake to prevent damage from soil insects and snails and to strengthen the plant growth. The young plants are often attacked by aphids which are controlled by neem seed aqueous extract. The extract is prepared by mixing 6 kg of ground seeds with 300 liters of rain water. This corresponds to 20 g per litre of azadirachtin. The mixture is allowed to stand for about 3 hours and is then sprayed to about 400 to 500 trees that are 8-10 years old. The applications are carried out in the evening, as soon as the incidence of aphids is registered. The application frequency depends from the population density of the aphids, but normally the farmer applies neem extract not more than 2 times a month. Leafminers, fruit fly maggots and whiteflies are controlled by using 0.3% neem oil emulsion. Neem oil is sprayed every 10th day. The controlling effect is not complete, but the losses due to insect damage are acceptable.

In the second example neem products are used in organic tomato production on the Canary Islands. The products used are formulated neem oil and cake powder. Neem oil is applied at a concentration of 0.7%. Depending upon the population density of the pests, the oil is sprayed every 15 days. According to the observations of the farmers the neem oil is effective in controlling whiteflies, such as Trialeurodes vaporiarum and Bemisia tabaci, leaf miners, such as Liriomyza species, different lepidopterous larvae, such as Spodoptera species, Trichoplusia species, Heliothis species. If the incidence of the lepidopterous pest is high the neem treatment is complemented by the application of Bacillus thuringiensis. However, the control of spider mites, such as Tetranynchus urticae, Poliphagotarsonemus latus is insufficient or in the case of Aculops lycopersici, there was no effect. Therefore, an additional preventive treatment of sulphur is carried out to control spider mites.

Also, aphids such as Myzus persicae and Aphis gossypii, are not controlled by neem oil application. They are controlled with another botanical pesticide. In the case of thrips, the farmers observed that the neem treatment did not affect the predatory bug Orius species which keeps the thrips under the economic threshold, whereas other botanicals like rotenone cause high mortality of the Orius population and checks thrips to become a major pest problem.

Neem cake is incorporated into the soil at a rate of 1.500 a 2.000 kg/ha in three different ways: pure, mixed with drug and incorporated into green manunre. The purpose of the application is not only to improve fertilization but also to control nematodes, predominantly Meloidogyne species.
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