Commercial Neem Based Products

8/14/2019 Commercial Neem Based Products

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Aza + Formulation

COMMERCIAL AND INDUSTRIAL ASPECTS OF NEEM-BASED PRODUCTS

The indiscriminate use of synthetic pes ticides in agriculture, horticulture, forestry, animal husbandry and in public health has created some undesirable problems .

Though these pesticides still constitute one of the essential components of IPM, reduction in synthetic pesticides consumption is envisaged by all concerned e.g.

government, farmers, pesticide industries, rural development agencies etc. Also, the motion of replacing them with plant products is widely acclaimed. Neem

pesticides offer a reliable, economic and eco-friendly solution and proved to be effective against a number of pests. The neem-based products / pesticides are

included in plant protection schedules of most of crops grown in India. Thus, many enterprises are interested in the production of neem-based pesticides. This

paper dis cusses the commercial and industrial aspects of these pes ticides so that quality products are manufactured and marketed, and farmers are aware of the

usefulness of neem products. The private companies and government organizations can als o start manufacturing neem-bas ed pesticides on commercial bas is.

In India, introduction of intensive cultivation practices has certainly helped the country to boost the food production. Synthetic pesticides were considered as an

important component of crop production system (Gahukar, 1992a), and received an overwhelming dem and from farmers who were convinced of high crop yields,

pest mortality due to quick knock-down effect and systemic action of some pesticides, long-term persistence of residues, easiness in application, availability ofsuitable formulations in local market, recommendations from government departments etc. Moreover, manufacturing firms took pesticides as business

opportunities to get profits. The marketing agencies comprising of dealers, distributors and retailers created a long-lasting impression on farmers and is the

propaganda of synthetics in such a way, sometimes by leading money or selling plant protection material on credit basis, that farmers were convinced. Farmers

considered pesticides as a boon but the research and development activities of government agencies being weak, proper and timely technical guidance to farmers

was lacking. The guidelines for safe and proper us e of pesticides were hardly followed by farmers due to illiteracy, ignorance of instructions, i nadequate knowledge

etc. (Gahukar, 1992b). Thus, overuse or misuse of these molecules has created some undesirable secondary effects in the agroecosystems and environment

(Gahukar, 1992a). Government did not consider the fate of farmers and did not foresee the steps to be taken in the event of natural disas ters as it happened in the

1997-98 crop season . Under such s ituation, some farmers could obtain maximum yield in food crops, cotton and vegetables by using non-chemical crop production

techniques including biofertilizers, biopesticides, plant products and neem-based pesticides. In general, there is an increasing demand for neem pesticides in the

market, and more and m ore pesticide m anufacturers are s elling these products or have planned for production units (technical or formulated material) (Table 1). The

purpose of this paper is to furnish complementary information on commercial and industrial aspects of neem-based pesticides so that plant products is promoted

sincethey are proved to be effective and economical, do not pose any threat to beneficial organisms and hum an, and are eco-friendly (Gahukar, 1995).

Different species of neem are used in different climatic conditions, e.g. Azadirachta indica for hot and dry areas; A. siamensis and A. excelsa for hot and humid

areas. A. indica is ind igenous to India where it is considered as kalpataru because it is a multipurpose tree (Ketkar, Kale and Tappire, 1976; Gahukar, 1995). In plant

protection, its potential had been exploited during late 1920s when 0.001% aqueous suspension of kernel was used to repel locust (Devakumar, 1996) Also,

Pradhan, Jotwani and Rai (1962) demonstrated antifeedant action of neem against des ert locust.

COMMERCIAL AND INDUSTRIAL ASPECTS

Planting

Since neem kernels form the major source of raw material for neem - based pesticides, people should be encouraged to plant neem trees not only in the open

spaces, fallow lands and on the border of their fields but in large areas on commercial basis. The industrial firms also get benefits as raw material is readily

available.

Gahukar (1997) explained the economical benefits of neem plantation. During the first 3 years of planting, mixed crops and intercrops are taken. In 10 years, neem

tree grows about 10 - meters tall and can produce 35 kg of leaves and 20 kg of kernels. As the tree grows, yields are higher 30-50 kg. On an average 2000 - 4000

seeds weigh about 1 kg. A minim um income of Rs. 60,000-75,000/ha/yr is poss ible.

Collection

It is estimated that there are 14 m illion trees in India. These trees produce annually about 540 000 m etric tonnes (mt) s eeds which can yield in 107000 mt of oil and

425 000 mt of cake apart from green leaves, bark, dry leaves, wood fire, timber etc. At present, only 20-30% of seeds are collected and the rest goes as waste.

Therefore, here is a necessity to organize the collection at village l evel. Leaves should be collected when flowers have not blossomed, roots during autumn (when

leaves are dry), bark during the rainy season as per large scale availability or when 20% fruits are yellow-ripe and 75% of them are physiologically ripe but still

green. Of course, there is a wide variation in the yield a quality of seeds when different ecotypes are planted. At present, people collect the seeds in their own

manner without quality consideration such as s eeds/kernels m ixed with dirt, crop refuse, weeds, sticks etc. Some birds (myna, sparrow, crows, owl, parrots) and

fruitbats eat the pulp and drop the kernels. Many fruits are infected with soil-borne fungi as fruits fall on the ground. This infection is carried further to the stores.

Better methods of collection can be:

Clipping the twigs with matured green fruits and collecting them in the bags. These fruits are then spread on tarpaulin / cloth sheets and left for 3-4 days

so that fruits ripe.

Harvesting ripe yellow berries by shaking the branches with stick or pole. Fruits fall on the cloth spread under the tree.

The ripe fruits are transported in wooden baskets or gunny bags for depulping. So fruits are cleaned before depulping. The sedimentation or gravitational

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method is simp le. Fruits are drenched in clean water (tank or trays) to remove stickiness on skin. Berries float on the surface and foreign matter and fraction

sink to the bottom. Fruits are removed from the tank and then spread on the cloth so that only good quali ty fruits can be selected for depulping. The following

methods are generally followed for small and l arge scale processing.

Mechanical destoner consi sting of hopper and rotary feeder has been introduced (Ramakrishna, Prasad and Azeemoddin, 1996). A powerful blower fan is

installed at the bottom so that air flow helps to separate fruits from heavy particles (e.g. stones, mud pel lets, sand etc.). Seeds are fruits and thrown out

through existing hood.

Depulping

The depulping process involves the operations of soaking, depulping and was hing.

Fruits are macerated and out in buckets filled with water. It takes 4-5 days to decompose the outer pulp and m ake it detachable. Skin of the fruits float on water and

is removed eas ily. Another method is to be macerated fruits in a wooden basket under a strong jet of clean water so that the pulp i s removed. The depulped s eedscan be stored safely up to s ix months. However, seeds to be used for kernel extract should be at least three months old and s hould no t be used after 8-10 months

due to low azadirachtin (AZ) content.

Decortication

On an average, a fresh fruit gives 35% depulped seed and a dried fruit gives 26% kernel by the process of decortication. Fresh fruits contain as high as 50%

moisture, semi -dried fruits 10-15% and well dried fruits only 9% moisture. At village-level, sun drying of fruits is the bes t method for storing them for a longer period.

By this way the mois ture content is brought down by 8-9%. If sun drying is imposs ible, fruits should be dried under the fan in the room.

Seed kernel weighs about 10% of the whole fruit and ratio of kernel to hull is 53:47% by weight. Storing of kernels in dry and airy place is important otherwise any

contact with moisture will spoil the quality of kernels. Saprophytic fungi easily invade moist berries or kernel and a common fungus, Aspergillus flavus Link which

produces aflatoxin is carcinogenic. Seeds with thin seedcoat and without fungal infection are preferred by oil process ors. The bark and roots are peeled , dried and

stored in big drums for further use. Proper storage facilities in villages are non-existent. Even the farmers co-operatives do not have well constructed structures.

Good storage is an urgent need because kernels or berries are available for short period whereas manufacturing units need seeds/kernels for oil production

throughout the year.

At present, mechanical decorticators are available in the m arket (Shivakumar et al.,1993; Ramakrishna, Pras ad and Azeemoddin, 1996; Patel, 1997). Seeds can be

decorticated in a d isc-type dehulle r fitted with granite and em ery discs. One disc is s tatic whilst other rotates at the speed of 600 rpm. A shaker-separator having

mesh screens and air-cyclone separator are s ynchronized with machine to get continuous supply.

Crushing

Neem kernel is a rich s ource of tetranortriterpenoids or m eliacins. The kernel fractions are crushed in a table expeller which are available comm ercially. There is no

preconditioning of expeller or pre-treatment of raw material and water is not at all added during crushing. Seeds are directly fed into the hopper and following steps

are followed, particularly for cold process ing (Ramakrishna, Prasad and Azeemoddin, 1996).

Kernels are put in the disintegrator and pressed in the expeller. The mass is humidified and crushed.

he kernels are passed through a single pair roller reduction mill. The flaked kernels are humidified and crushed.

The expeller is pre-conditioned by pass ing oil cake of the previous step through the expeller till the shaft-mounted worm attains a temperature of 65C. The already

flaked Kernels are crushed.

The oil obtained in each step is filtered in cold using a hand-operated filter press.

In this processing, there is a loss of only 1% of material. However, if temperature of expeller/crusher during processing is above 50C, AZ in neem oil gets

completely inactivated and further utilization of oil for pesticide formulation is not worthwhile. Therefore, cold press ing of kernels in a screw press and keeping the

temperature below 50C is found to be suitable because AZ content in neem oil is ca. 1700 ppm. Hydraulic pressing of kernels is effective but may not be

economical as oil yield is comparatively low. The Bureau of Indian Standards (BIS) has established certain requirements for seeds and kernels meant for oil

extraction (Table 2).

Oil extraction

The oil content in whole seed and kernels is 21% and 50% respectively. Under certain circumstances, oil content is found to increase during storage from initial

value of 39% to a final value of 39% to a final value of 45% in a period of 10 weeks. An ideal neem oi l should possess certain characteristics (Table 3). Likewise, BIS

has specified certain properties of seed oil and kernel oil (Table 4). Though extraction of oil from well dried seeds is possible, kernels are preferred due to certain

advantages (e.g. maximum oil yield, less impurities, better physical properties etc.).

The neem oil can be extracted by different processes , which are descr ibed below.

Traditional ghanis:

In olden days, ghanis were widely employed in villages. The system consists of a wooden mortar and pestle. Seeds are crushed by revolving the pestle in the

mortar with the help of a bullock tied to the beam. This system does not exist anymore. In the ghanis, 40% oil can be obtained. This quantity is lesser than oil

extracted in the oil mills but quality of oil is superior.

Oil mills:

The expeller crushers are comm on with a crushing capacity of 5 - 20 tonnes / day. In some oil mills , mortar made of cast iron is us ed. About 15% oil and 77% cake is

thus produced. It is certain that high temperatures of expellers inactivate AZ although quantity of oil may not be affected.

Recently, Ramarethinam, Viswanathan and Rajagopa l (1997) im proved the methodology of neem oil extraction where the pestle alone revolves or both pestle and

mortar revolve with the help of a power driven motor. In order to avoid any alteration in the constituents of oil or cake, wood is used for fabricating both the pestle and

mortar or at least the surface of contact is in wood. The pestle and mortar are allowed to rotract @ 500-600 rpm for 2-3 hours. By this way, oil yield is 15-20% less er

than the oil obtained in power driven mills where metal is used.

The major difficulty in this technique is that oil being highly viscous, the s queezed biomass of the s eed gets coagula ted and oil oozes out very slowly. Therefore,

authors cons idered som e relevant points (e.g. viscocity, flocculation, exchange of cations, critical flow velocity, colloidal fineness, principles of Vander Walls forces)

and us ed polysaccharides (e.g. molas ses, crude sugar / jaggery etc.) as an additive @ 200 ml/4-6 kg seeds or kernels, at the final stage of crushing. This helps to

loosen the bonds between the oil and s olid state molecules which have a direct bearing on the critical flow velocity required to separate the coagulated oil-biomass

blend into oil from the cake.


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.

Steam distillation:

This simple method of extracting oil has been des cribed by Baliga Pisat and Argekar (1996). The unit consists of a condenser, a separator and a generator. The

still prim arily serves as a container for the plant material. It is a cylindrical vertical tank equipped with a removable cover. On the top of the cylindrical s ection, a pipe is

attached for leading the vapours to the condenser. At the bottom, there is a grid on which the material rests and live steam is introduced.

Fresh matured leaves are chopped in to small uniform bits after cleaning them. These leaves are uniformly distributed on the top of a perforated plate at the bottom of

the still. The saturated steam is injected through the charger by means of open pe rforated coils below the perforated platform on which leaves have been placed.

Most of the aromatic volatiles are vapourized after diffusing out as an aqueous solution through the cell mem brane. The vapours are condensed in a condens er.

The oil and water is collected in a bas in from where the oil is collected by a separator.

Solvent Extraction:

It is always preferred to extract oil without heat treatment or cooking. In this method, oil and its constituents s uch as fatty acids and lipoproteins, are dis solved in the

solvents. It is essential that thermolabile and photolabile constituents of neem oil mus t be retained for the purpose of formulation.

The advantage of this m ethod is that impurities in oil (e.g., coarse s uspended matter, insoluble carbohydrates, insoluble proteins, mois ture and glycerol diss olved

therein, colloidal or solub le proteins, gums and resins , free fatty acids, colouring and odorous m atter) as rem oved by solvents.

Sedimentation or settling method:

Big tanks / fermentors are used and therefore, the cost is higher than other methods of oil extraction. Oil is more fermented as i t remains in contact with fermentors

for a longer time. Oil can be filtered through Fullers earth of which appropriate grade must be used.

Cold pressing:

This process of oil extraction is recent, economically viable and has become popular as formulations based on AZ-enriched oil containing 1500-2500 ppm AZ are in

great demand. Kernels are pressed in a screw type press keeping the temperature comparatively low (e.g.


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o-pers s ence n e envronmen .

Low rates of application (52/140C

Boiling point :165C

Melting point :180C

Solubility at 25C :in water: 0.00005 mg/ml, in acetone: 6.25 mg/ml,

Ethanol : 0.125 mg/ml, methanol : 0.10 mg/ml

Relative dens ity :1 .4 g/m l a t 24C

Stability :Stable for a year in the absence of water, high temperatures and light. If temperature is > 50C, AZ molecules break

down very rapidly

Mammalian toxici ty :It is hydrolysed completely in sterile deionised water after 100 h at 50C. AZ decomposes even in pure form and in

organic solvents. Unstable under sunli ght

Acute dermal LD50

for rabbit :2 ml/kg body weight

For rat :600 mg/kg body weight Moderate pr imary irr itation to skin and minimal ir ri tation to eyes.Acute oral LD50 for

hen:6500 mg/kg body weight

For rat :5ml/kg body weight

Isolation of AZ

First isolation i f AZ was tried by Butterworth and Morgan (1968). Nevertheless correct structure of this m olecule was not established until mid 1980s (Broughton et

al., 1996).

Generally, AZ is isolated by using solvents. Seeds/kernels are macerated in ethanol. The Solution is filtered and the filtrate is evaporated and the residue is

partitioned in a m ixture of light petroleum + aqueous methanol (5:95 proportion). The methanol portion is then exposed to column chromatography on Floridin earth.

Then, elution is done with a mixture of ether + acetone (95:5 proportion). Nuclear Magnetic Resonance spectrometry is used to separate fractions containing AZ. Thin

layer chromatography on s ilica, eluting twice in a mixture of ether + acetone (95:5 proportion) is followed. Polar s olvents give better results than non-polar so lvents.

Zanno et al.(1975) reported the instability of AZ in chloroform solution but Morgan (1981) found AZ dissolved in CDCL3 to remain unaltered for about one year

provided the extracts a re maintained under neutral condition.

Ganesh Kumar et al.(1994) prepared the powder of neem kernels using a heavy duty blender. This powder (50 g) was de-oiled using light petroleum ether (40-

60C) by soaking over night and als o by stirring repeatedly four times in 50 ml portions. The de-oiled powder was filtered using a Buchner funnel under suction. The

residue in the filter paper was transferred into a 500-m l separating funnel and AZ was extracted by partitioning with azeotropic mixture (e.g. methanol: methyl tertiary

butyl ether, 15:85). The process was repeated four times and extracts were pooled, and then were condensed using a rotary vacuum flash evaporation to a moist

residue. The residue was dissolved in methanol for HPLC determination. In case of extract, it was elutioned in a silica column with hexane: ethyl acetate (1:3),

evaporated and taken in methanol for AZ determination.

High performance liquid chromatography (HPLC) is now employed to determine AZ content due to its excellent results (Sundaram and Curry, 1993; Udaiyan et

al.,1995). The HPLC unit is equipped with microsyringe (25 ul capacity) and ultra violet (UV) detector and printer-plotter cum integrator. AZ is detected by measuring

absorption at wavelength 217 nm . A column clean up method to remove aliphatic and arom atic solvent components and different surfactants present in formulations

was developed by Azam, Rengaswam y and Parmar (1996). HPLC i s difficult because of the extensive pre-purification and sens itivity of the detector s ystems. These

techniques are costly also. Therefore, Thejavati et al.(1996) developed a multidimensional frontal chromatography using stationary phases like cellulose,

polyvinylpyrolidine and crosslinked polystyrene divinyl benzene polymers and mobile phase like aqueous alcohol, and AZ of over 90% purity could be obtained.

Baeckstorm and Zandra (1993) described a simple technique of AZ isolation from ground seeds by combining the extraction and chromatography in the same


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column using special types of gradients. Other techniques like reverse-phase liquid chromatography eluting with a mixture of methanol: water (60:40) and

acetonitrile: water (70:30), gas chromatography, sili ca-gel chromatography etc. have al so given satisfactory results.

The operating conditions used by Udaiyan et al.(1995) were:

Column: C18, 25x4.6 mm, stainless steel, 5 u particle size or equivalent.

Flow rate: 1 ml/min.

Mobile phase: methanol: water (60:40, v/v)

Inject volume: 20 ul.

Retention time: 3.2 min.

AZ content (%w/w) is calcu lated by the following formula (Udaiyan et al., 1995).

A1 M2

--------------- x ------------------- x P

A2 M1

A1 : peak area of AZ in sample solution injected.

A2 : peak area of AZ in reference s tandard in jected.

M1 : mass (g) of the sample taken for the test.

M2 : mas s (g) of the reference standard AZ.

P: Purity of reference standard AZ.

Neem extract: An extract is a derivative of kernels, seeds, leaves or bark for which the active principles are unspecified, uncharacterized and/or not quantified.

Farmers can easily prepare the extracts with limited finance and little knowledge (Gahukar, 1996) but there are some disadvantages, such as, application

immediately after preparation, variable quality, high volume of spray liquid required per unit area etc. Large-scale production is therefore possible only in

manufacturing units.

The general procedure is to use aqueous extract as solution in water while other extracts are first dissolved in solvents and then diluted in water containing

emuls ifier. The common solvents for extracts are ethanol, benzene, acetone (@ 5-10%). The em ulsifier is Triton X-100 (@ 0.5-1.0%).

In another method, neem kernels are ground to powder in an electric blender and powder is s tirred and filtered through filter paper using vacuum pump. The content

is s tirred again followed by the filtration. The combined extracts are then freed of water in the evaporating dishes at 60C using a hot air blower. The solvents of

different polarity are used to obtain different extracts. For example, in ethanolic extract, the combined extracts are freed of ethanol under reduced pressure of 50C in

a rotary vacuum evaporator. In hexane extract, kernel powder is stirred with hexane in a blender and filtered. The extract is restirred in hexane and the same

procedure is repeated until de-oilation occurs. Pooled extracts are freed of hexane at 50C. The residue left is dried under fan and collected as de-oiled kernel

powder. For chloroform in a magnetic stirrer and filtered. Chloroform is evaporated under reduced pressure at 50C in a rotary vacuum evaporator.

The amount of NSKE obtained in different solvents is given below (Jhansi and Singh, 1996).

Water (100 g): water soluble (19.10 g) + water insoluble (80.90 g)

Ethanol (100 g): ethanol soluble (15.80 g) + ethanol insoluble (84.20 g)

Hexane (100 g): oil (43.00 g) + Deo lid kernels/cake (57.00 g)

Oil (43 g): ethanol: ethanol soluble (6.45 g) + ethanol insoluble (36.55 g)

Cake (57 g): chloroform soluble (4.73 g) + chloroform insoluble (52.27 g)

For the kernel extract, a new process ing technology has been developed by Visetson and Naknatti (1996). The technique consis ts of 3 systems: storage, circulation-

pressure, power system. Two barrels with 4 joints connected, polyvinyl-chloride pipes and motor driven water power pump are main equipment. The machine

functions by circulation of water pressure and water percolation using the pump. About 6000 1/ha are pumped through a 20-1 linen bag packed with 5 kg of crushed

kernels. The bag is put in a 20-1 porous plastic tank. All systems are connected within the two 200 1 barrels. The extraction procedure lasts only a hour. These

extracts are found containing 50 ppm of AZ. This i s a simple process that farmers can use at the farms for large scale production.

Emulsifiable concentrate (EC):

The bioefficacy of a s pray depends upon the amount in itially retained by the treated surface and i s determined by the rate of evaporation and viscocity.

EC is a concentrated solution of AZ or other a.i. to which emulsifying agents are added. Emuls ion is prepared after adding water to EC which consis ts of droplets of

oil containing the pesticide dispersed in water which is the continuous phas e. Each droplet is surrounded by water and the emuls ifying agents reduce the interfacial

surface tension between the oil and water s o that oil droplets are prevented from coalescing. An ideal emulsion is hom ogenous, s tays stable for a long time, does

not break down while spraying. Sometimes, emulsion breaks quickly because toxic dispersed phase comes into play or greater part of water which forms the

continuous phase evaporates quickly. On the foliage which is water repellent, the emulsion breaks down quickly. There is no run-off and oil is deposited as a thin

film. Thus, em ulsion diluted with water does not cause any phytotoxic effect and gives h igh initial deposit of the chemical and complete coverage of waxy surfaces is

possible. It is therefore commonly used in agriculture.

Neem oil with low viscocity produces spontaneous emulsion and is advantageous for the formulation of emuls ifiable concentrate. Both polar and non-polar s olvents

(e.g. aromax, cyclohexane, xylene) are used at 10-15% to reduce oil viscocity in the formulation. Therefore, an optimized combination of a nonionic emuls ifier (HLB

range: 5-18) and anionic emuls ifier is used . Use of mixed solvents is also pos sible for optimal performance of the formulation.

The EC prepared by using appropriate s urfactants provide excellent stability on dilution, especially if one of the hydrophobic solvents i s s urface active. In solvent-

based formulation, chemical stability of a. i. in the concentrate is a major concern. Therefore, knowledge of the kinetics of decomposition and evaluation of activation

energy for temperature should be used in computation of s tability.

The factors affecting emulsion stability are:


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, , , , , .

Agent: Chemical constituent, concentration, solubili ty in continuous phase, pH of aqueous phase, physical properties of film around the particles, thicknes s of

film, partial deformations, influence on the attractive between particles, electroviscous effect, electrolyte concentration in aqueous medium .

Conditions: Temperature, light, pressure.

In laboratory, emuls ion stability can be determined by knowing the rate of cream separation. This m ay be m easured using a cone-shaped centrifuge tube or a

calibrated cylindrical tube or by measuring changes in the optical density (OD) in various portions of an em ulsion. The OD of creamy layer increases whilst OD of

rest of emuls ion decreases. The stability of oil in water type emuls ion can be determined by using several types of water at 40-90C (e.g., soft water, alkaline

water.) Repeated stability tests for neem formulations during s torage periods are advisable (e.g., before the expiry date, extended date, extended period of s torage

etc.)

The emulsion mus t be stable. It means there should not be signs of separation or creaming upon standing 15 minutes or longer because emu lsions have a

tendency to separate into components from which they are prepared. This process is known as breaking of emulsion. When the toxic dispersed phas e breaks

immediately after application it is known as Creaming of emulsion. Breaking is possible due to difference in the specific gravity between the dispersed and

continuous phase. The rate of creaming depends upon the differences between dens ities of the two phases and by the size of the droplets of the dispersed phase.Neither the concentrated emulsion nor the diluted emulsion in the spray tank should break before applications. It is therefore desirable, at least for some s prayers,

to have low concentration of emuls ifiers to reduce the poss ibility of foam formation as creamy layer may occur in 2-3 minutes in the abs ence of agitation. In less

stable emulsion, care is needed so that a re-emulsification with least agitation is pos sible. However, unstable emulsion is advantageous for foliar sprays as spray

liquid falls off the leaves to ground and more toxicant is deposited from an oil phase. Where partial coverage is desired, the stability of emulsion is les s im portant

than wetting property of the spray.

Emulsifiers:

The main function of an emulsifier is to modify the properties of the interface between the dispersed and continuous phase .

The choice of emulsifier to be used in EC depends upon the properties of em ulsifier, e.g., structure polydispers ity, Hydrophiliclipophilic balance (= HLB value), phase

inversion temperature, solubility in water and oil phase, Kraft point, surface tension, interfacial tension with m odel s ystem (oil/water), dynamic s urface tension, critical

micelle concentration, synergy with other emu lsifiers, wetting efficiency, capacity to form comp lexes with so lvents and polymeric stabilizers. Since the formulation is

complex, the choice of emuls ifiers is critical and an optimization process shou ld be tried before optimization of the emulsifier s ystem.

The emulsifiers are of three types:

Anionic: These are sal ts of an oil soluble anion. Ex: carboxylic acids , sulphuric esters (sulphates ), alkane sulphuric acids , alkyl aromatic sulphonic acids ,

phosphates and phosphoric acids, persulphates, thiosulphates, sulphonamides, sulphamic acids.

Cationic: These are salts of an oil soluble cation. They are incompatible with anionic types and should not be used in the same formulation. Ex: amine salts,

quaternary ammonium compounds, quaternary bases, phosphonium compounds, sulphonium compounds. Some of the recently developed cationic emulsifiers

are: alkyl (C8-C18) sulphates, alkyl (C8-C18) benzene/toluene/xylene sulfonates, alkylphenyl ethoxylated phosphates/sulphates (C8, C9, C12-C16 alkyl), dialkyl

phenyl ethoxylated phosphates/sulphates (C8,C9,C12-C18 alkyl), ethoxylated tristyryl phos phates/sulphates as s odium, calcium, am ine or alkanol am ine s alts.

Non-ionic: These emulsifiers consist of organic esters and ethers and have non-souble action. These emulsifiers are compatible with other two groups. Ex:

ethoxylated fatty alcohols (C8-C18 alcohols), ethoxylated alkylphenols (C8, C9, C12-C16 alkyl), ethoxylated castor oil, ethoxylated alkyl amines, ethoxylated tristyryl

phenols, s ucrose ethers (C8-C-18 alkyl).

In India, non-ionic emulsifiers (maximum limit of 10% in the formulations of neem-based pesticides) are widely used such as, Emco1R (ethylene glycol fatty acid

ester, propylene glycol fatty acid ester); TweenR (polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan tri-oleate), Triton-XR etc. Also, paired emulsifiers are

being manufactured with wider applications in pesticide formulations and old emulsifiers like soaps (alkali salts of fatty acids)) are being replaced by synthetics

which are mos tly of anionic type because soaps have bulky molecules, carbon chain exceeding a certain length (about c12) which form the non-polar water ins oluble

group. Even in the polar group hydrogen is replaced by a suitable alkali m etal (sodium or potas sium). Also, soaps react with hard water and curd is formed whereas

a sm all am ount of synthetic emulsifier to lower the s urface tension of a relatively large of water.

The solvent-based EC is advantageous due to ease of use, ease of formulation and g reater bioefficacy. They are preferred for foliar applications since they tend to

enhance uptake and translocation due to be tter penetration, cuticular solubilization and s tomatal entry. They also influence the uptake due to cuticular diffusion or

stomatal infiltration. The solvent should have low evaporation rate. However, the disadvantages of EC are: phytotoxicity from solvents/surfactants, container

incompatibility dermal and ocular toxicity.

Spreaders: The spreader promotes the formation of the li quid-solid interface by reducing the energy associated with its formation, and helps to improve coverage

and to enhance tenacity. Soaps also act as a s preader. It is usually recommended for mixing with water extract of neem leaves or kernels but wetting property of

soap is lost in hard water. Other spreaders are alkyl sulphates or sulphated alcohols which are available commercially by the tradenames Teepol, Tergitol,

Dispersol, Sandovit, Tween, Triton X-100, Liss apol etc. The efficiency of a spreader is determined by the following criteria:

Wetting properties: It should form a stable reduced liquid -solid interfacial tension or liquid s hould be s lightly soluble in the solid s urface. If wetting is abs ent,

the liquid tends to form a droplet and s ubsequently, it drops off from the plant s urface. Therefore, contact angle between liquid droplet and soli d surface

should be zero.

Spreading properties: The sp reading quali ty is expressed by the formula:Wettability or spreading coefficient surface tension of solid

(ST) + su rface tension of liquid (LT) interfacial tension (IFT).

Since ST and IFT cannot be meas ured, the amount of adhesion is calculated by the contact angle the liquid droplet m akes with sol id surface.

W= LT (1 + cos 0)

When the contact angle approximates 0, the liquid has equal attraction for the solid and liqu id. Any reduction that is effected in LT increases the ability of the liquid to

spread and reduce its contact angle with solid.

Penetrating properties: The rate of penetration and spreading depends upon the viscocity of the liquid and is obtained by absorption of spray material through

cotton wool or unbleached cotton cloth. The formula is :

Penetrating efficacy = LT Cos 0

2 N

=


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,

N= viscocity of liquid.

Solvents:

Any solvent should have high solvency for toxicant, low volatility, non-inflammability, high flash point if inflam mable, low phytotoxicity, low viscocity, high availabi lity and

low cost.

In EC formulations, so lvents based on petroleum dis tillates are commonly used. If insoluble ma terials are to be used, an intermediate or mu tual solvent (e.g.

stabilizer, blending agent) is needed. The capacity of solvent to hold an ins ecticide in solution at subnormal temperatures varies considerably. Different types o f

solvents are presently available for the formulation purpose.

1. Aliphatic petroleum products: kerosene, mineral oils , diesel oils.

2. Aromatic petroleum products: xylene, toluene, benzene, naphthas .

3. Alcohols: butanol, methanol, ethanol.4. Chlorinated hydrocarbons: carbon tetrachloride, chloroform, ethylene dichloride, m ethyl chloride.

5. Esters : butyl acetate, methyl aceate.

6. Ethers: diethyl ether

7. Ketones : acetone, cyclohexanone, diacetone.

8. Vegetable oils: cotton seed, linseed, sesamum oil.

The modern surface-active solvents include N-methyl pyrrolidone, N-octyl pyrrolidone, N-dodecyl pyrrolidone, butyrolactone, alkylbiphenyls, tetrahydrofurfuryl alcohols

and ethers. For neem pesticides, only alcohols and aliphatic sol vents are used as benzene can produce cancer in humans .

Dispersing agents:

These protective colloids give uniform spray by preventing sed imentation which is caused by increased viscocity of the liquid medium in which the rate of fall of the

sedim ent is inversely proportional to surface adsorption of the solid particle. Thus, solid particles become surrounded by a liquid s hell of sim ilar density to the

surrounding l iquid. The water dis persible derivatives of cellulose (e.g. sodium carboxymethyl cellulos e, methyl cellulose etc.) are commonly used.

Granules

Urea granules are coated with neem products to reduce volatilization of amm onia by delaying rapid urea hydrolysis and nitrification. On the contrary, kernels are cold-

pressed or neem extracts are us ed to produce pellets. This way helps to retain the natural balance of mine rals, trace elements and nutrients. This technology has

been developed by M/s. Keycer Agro Products Limited, Salem . For 100 kg urea, a mixture of 20-30 kg neem cake + 3 kg tar + 5 -6 kg kerosene is prepared and

granules are covered.

IMPORTANT CONSIDERATIONS

1. Registration and License for manufacturing and selling:

Neem pesticides are registered under the Insecticides Act, 1968. Therefore, for manufacturing neem pesticides, registration with Central Insecticides Board (CIB) is

compulsory. Interested pers ons can contact the Secretary, Central Insecticides Board and Regis tration Com mittee, Directorate of Plant Protection, Quarantine and

Storage, Govt. of India, NH IV, Faridabad 121 001 (Haryana) for all concerned formalities. The licens e is iss ued by the agriculture department of the state

government after the recommendation of CIB. The temporary registration is valid for two years. During this pe riod, one has to furnish the da ta (See Annexure) onneem-based pesticides whether they are meant for indigenous use or export purpose.

2. Processing

Collection of fruits and kernels is a seas onal operation lasting for four months (March-June) though oil mills operate for a longer period. Neem trees are scattered

and collection of seeds or kernels is difficult (Palaniswamy, 1992). One can collect manually only 2-3 kg kernels in an hour. Therefore, government should initiate

some system of encouragement for tribal, labourers and farmers. However, inexpensive production should not be achieved at the cost of the poss ible

socioeconomic im provements. There is a scope for mechanization of seed harvest / collection.

Neem cake obtained from solvent extracts is norm ally useless for pest control. Fungal infection in s eeds/kernels is becoming a m ajor problem s ince importing

countries do not accept such stocks of neem oi l or neem-bas ed formulations.

3. Shelf Life

Shelf life is an intrinsic p roperty of the product and can be enhanced by a better product design. In general, AZ content in kernels , cake and kernel powder decreases

only by 20% under proper drying and storage conditions than m any formulated products (Kleeberg, 1996). Therefore extracts are best for farmers as they can

prepare themselves with limited finance and technical knowledge. The cost of treatment may not be more than Rs . 200-300/ha. However, aqueous extracts are not

marketable because AZ degrades rapidly the microorganisms develop easily which spoil the qua lity. All formulations can be stored s afely for a year under ambient

conditions. However, Udaiyan et al.(1995) claimed that AZ content in the com mercial product Nimbecidine is not deteriorated even after 30 m onths of s torage when

polyethylene bottles are used for which these authors referred as container content compatibility.

4. Stability

In the field, residual activity of neem pesticides lasts only 3-7 days because AZ and other constituents of neem oil are sens itive to ultra violet (UV) radiation from

sunlight and high temperatures (Koul, Isman and Ketkar, 1990; Gahukar, 1996). Therefore, UV absorbents and anti-oxidants are to be added and spraying needs to

be done during cool weather (e.g. morning or evening). The role of anti-oxidants is doubleful as m echanism o f decomposition

is not fully understood. The type of neem oil in the formulation and its pH are also important (Udaiyan et al., 1995).


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Neem products are quite s usceptible to hydrolysis and are degraded rapidly in water (Szeto and Wan, 1996). The isolation of hydrogenated derivatives of AZ (e.g.

dihydro-AZ and tetrahydro-AZ) and radio-active precursors showed some hope due to their longer res idual activity than the base m olecule and could resis t better in

sunlight (Akhila, 1996). Further, Mohapatra et al.(1996) recommended pre-gelatinized s tarch encapsulated formulations which are found to be quite s table in the

sunlight. Intensive research on synthesis of novel AZ isomers m ay also offer a vital poss ibility to develop simpler synthetic analogues .

TABLE 2

Requirements for kernels and depulped seeds for oil milling . (IS-7787, 1975)

Characteristics Kernels Seeds

Damaged and weeviled (% by mass, max.) 3 3

Slight ly damaged and weeviled (% by mass, max.) 8 8

Shrivelled and immature (% by mass, max.) 5 5

Spilt and broken (% by mass, max.) 5

2

Impurities (% by mass, max.) 4 6

Moisture content (% by mass, max.) 8 8

Oil content (% by mass, max.) 45 22

Acid value of extracted oil (max.) 10 12

Data on the degradation of neem pesticides under different agroclimatic conditions in India are lacking. AZ decomposes more rapidly in aquatic environment than

synthetic pesticides. Therefore, stability of AZ in water-based spray mix and biodegradabil ity in aquatic m ix should be studied.

5. Standardization

The Bureau of Indian Standards has formulated certain standards for quality control and moni toring of neem products/pesticides (Kumar, 1996) though declaration

of active ingredient (e.g. AZ) is compulsory under the provision of the Insecticides Act, 1968.

IS 4765 (1975) : Kernel oil and depulped seed oil:

The oil should be free from adulterants, sediments, suspended and other foreign matter, separated water and colouring substance. Other requirements such as,

admixture with other oils, colour, moisture, refractive index, iodine value, uns aponible matter have been s tandardized.

IS 7787 (1975): Kernels and depulped seeds for oil milling:

The seeds s hould be harvested from neem trees. Seeds should be cleaned, damaged by insects, shriveled, immature, spilt, broken with impurities. Other

requirements of s tandardization include moisture content, oil content and acid value of extracted oil.

IS 8558 (1977): Cake for manuring:

Cake should be of uniform texture, clean, and free from adulterants (sand, dust and metallic pieces). Other quality parameters s uch as, sieving, mois ture content,

water insoluble organic content, total ash and acid insoluble ash have also been s tandardized.

General characteristics of neem oil

Characteristics Range Average

Colour - Greenish brown


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Taste - Bitter

Odour - Garlic

Viscosity (HLB value) 10.9-11.1 11.0

Minimum moisture and insoluble impurities (weight) - 0.3%

Lovibond colour (1/4 inch cell) - 45.0

Not deeper than

Refractive index at 49C 1.4615-1.4705 1.4658

40C 1.4632-1.4701 -

Specific gravity 30C 0.9087-0.9189 0.9129

Saponification value 193-205 195.6

(mg KOH/g oil)

Unsaponifiable matter (%) - 1.50

Iodine value (Wijs method) 68-75 69.2

Maximum acid value 9-15 11.2

Maximum unsaponifiable matter (weight) - 2%

Minimum titre - 36C

Optical density (640 nm) 0.308-0.510 -

(570 nm) 0.368-0.799 -

Palmitic acid (%) 18-20 -

Stearic acid (%) 18-21 -

Oleic acid (%) 42-45 -

Linoleic acid 13-16 -

Arachidic acid 1-2 -

IS 14299 (1995): Extract concentrate containing AZ:

The formulation contains an extract from seed kernel or depulped seed and i s in the form of light to dark brown powder or granules with a repulsi ve odour. Details

on AZ content, acidity/alkalinity, aflatoxins content, mois ture percentage, material ins oluble in acetone a re to be furnished.

IS 14300 (1995): Emulsifiable concentrate containing AZ:

The brown viscous formulation i s bas ed on the extract of kernels or oil. Details on cold test flash point, emulsion stability, heat stability, acidity/alkalinity, aflatoxins

content etc. are needed.

TABLE 4 : Requirements of neem kernel oil and depulped neem-seed oil (IS-4765, 1975)

Characteristics Kernel oil Seed oil

Moisture, insoluble impurities (% by mass, max.) 0.3 0.5


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Colour (in 14 inch cell) not deeper than 45 55

Refractive index at 40C 1.4615 1.4705

Saponification value 180-205 175-200

Iodine value 65-80 65-80

Acid value (max.) 15 20

Unsaponifiable matter (%, by mass, max.) 2 2

Titre C (min.) 36 36

6. Bioefficacy

Due to the slow action of neem pes ticides, the term insectistat inplace of insecticide has been propos ed. In order to prove the bioefficacy of neem pesticides,

field trials during 2-3 years are undertaken and the results are confirmed. Apart from photodegradation and biodegradation, sprays from neem pesticides m ust be

directed against s ensitive stages/instars of the target pest (e.g. larva nymph). Because neem insecticide acts as an ins ect growth regulator, antifeedant, sterling etc.

and its pesticidal action is poss ible only at higher doses which increase the application cost.

Generally 10-20 g AZ/ha is required for satis factory pes t control. Yamasaki and Klocke (1987) reported that the free hydroxyls and/or hydrogenated derivatives of AZ

are essential for antifeedant activity. Later, Ley et al.(1989) concluded that hydroxyl dihydrofuran portion of AZ may alone be responsible for greater antifeeding action.

Salanin is another constituent, which is found in greater concentration in neem oil extracts, which can be exploited comm ercially.

Resistance of pests to neem products is pos sible in long term but the development of resistance is slow and unstable because neem derivatives combine di verse

active principles and modes of action. The biodegradable nature of neem oil minim izes the environmental pollution as in the case of oil based 0.03% AZ containing

EC, AZ content starts weathering rapidly but efficacy persis ts for a week probably because oil i s a natural mixture of di fferent terpenoids which have varying degreesof bioefficacy. There is a direct positive relationship between the dose of AZ and pest mortality and after certain dose the effect declined (e.g. 30-50 ppm in larvae).

Therefore neem oil with o r without AZ is effective (Devakumar, Goswami and Mukerjee, 1985). Also, more terpenoids are present in oil than i n NSKE. It is therefore

necessary that neem-based product and not AZ-based formula tions shou ld be recomm ended in IPM (Ramarethinam, 1998) and there is no need to increase the AZ

content in formulations as natural balance of neem constituents is di sturbed.

ANNEXURE

Data requireme nt Indigenous Export

Use purpose

A. CHEMISTRY

1. Detailed chemical composition. R R

2. Source of import. NR NR

3. Common name, strain and natural occurences. NR NR

4. Specification along with undertaking for R RProduct quality.

5. Outline of process of manufacture, raw material R NR

used.

6. Physico-chemical properties. R R

7. Method of analysis. R R


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. .

9. Name of the part of plant(s) to be used for R R

extraction of a.i./components.

10. Method of experiment in detail clearly identifying R R

the chemicals.

11. Shelf life. R NR

12. Criteria used for identification, such as, NR NR

morphology, biochemistry and/or serology/

immunology.

13. Identification and quantification of identifiable NR NR

14. Outline of process of manufacture, raw materials NR NR

used.

B. BIOEFFICACY

1. Bioeffectiveness (two seasons/ two trials under two R NR

different agroclimatic conditions).

2. Phytotoxicit y R NR

3. Compatibility with other chemicals. R/NR NR

4. Direction concerning dosages. R NR

5. Time of application. R NR

6. Wait ing period R NR

7. Application equipment. R NR

8. Data on non-targeted organisms (toxicity to two R NR

species of parasites and predators)

9. Registration status in other countries, if any. R NR

C. TOXICITY

1. Acute oral toxicity in rats and mice. R R

2. Acute dermal toxicity. R R

3. Primary skin irritation. R R

4. Irritation to mucous membrane. R R

5. Acute inhalation toxicity . NR R

6. Allergy/sensitisation/immuno-suppression. NR NR

7. Toxicity to birds, fish, honeybees, silkworm. NR NR

8. Neuro-behavioural toxicity. R NR

9. Reproductive toxicity. R R

10. Mutagenicity . R R

11. Carcinogenicity . R R

12. Effect on spray operators (Health records). R NR

13. Human toxicity information. NR NR

14. Signs and symptoms of poisoning and treatment. NR NR


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D. REPEATED EXPOSURE STUDIES

1. Oral toxicity: pathogenicity (90 days). NR NR

2. Dermal toxicity: pathogenicity (90 days). NR NR

3. Inhalation toxicity: pathogenicity (14 days). NR NR

E. PACKAGING AND LABELLING

1. Type of packaging (packaging material). R NR

2. Manner of packaging (container content compatibility) R NR

3. Manner of labelling. R R4. Specifications for primary, secondary and transport R R

packaging.

5. Labels and leaflets: seven copies as per exist ing norms R R

6. Information along with undertaking for safe storage, R R

handling and transportat ion as per the Insecticides

Rules, 1971.

7. Process of manufacturing. R NR

8. Undertaking for manner of packing that the packing NR R

systems proposed are as per requirements of the

importing country.

7. Synergism

It is proved that several substances act as synergists and enhances the activity of neem pes ticides (Gahukar, 1995). For example, plant derived oils (s esamum oil),

chemicals (piperonyl butoxide), biopesticides (Bacillus thuringiensis, nuclear po lyhedrosis viruses, baculoviruses etc.). Also, the effect of neem-based pes ticides on

releases of predators, parasitoids and pathogens needs to be evaluated urgently.

The chemical pesticides can be dil uted with neem oil em ulsion prepared at recommended dos es ins tead of preparing spray fluid with water. This m ethod can

reduce the pesticide load by up to 30% (Ramarethinam, 1998).

8. Patent protection

At present, patent protection does not exit which needs attention of policy makers. Recently, poli tical leaders warned the Indian government to resist the move of the

United States on neem pa tent and to oppose the propos al of the World Trade Organization. Because integration with the global economy should not mean that neem

can become others property. An amendm ent of the Indian Patents Act 1970 is s till being di sputed since it will provide exclusive marketing rights in the field of

agriculture and health without any social and environmental restrictions or responsibi lities. The patents owned by US and Japanese firms have been dis cussed by

Vijayalakshmi, Radha and Shiva (1995). Two US companies, W.R. Grace and Agridyne, have set bases in India in collaboration with P.J. Margo and Aftaab

Investment Company respectively to manufacture plant extracts and sell the products in the US. The patent accorded to W.R. Grace in 1992 is being revoked on the

ground that their methodology is a m ere extension of the processes that Indian farmers have been using for hundreds of years. AZ is therefore a natural product

found in neem seeds /kernels and its onl y synthetic form can be patented. This challenge is a test of the intellectual property laws es tablished by the General

Agreement on Tariff and Trade and the World Trade Organization.

9. Germplasm

Proper ecotypes can be developed by genome mapping, tiss ue culture, air layering of branches etc. High yielding cultivates adaptable to various climatic conditions

are now available at research stations in India. The Central Res earch Institute for Dryland Agriculture, Hyderabad (Andhra Pradesh) has developed the neem slones

with faster maturity, high yield of seeds and quality wood, high content of AZ and oil. However, plantation from a single elite neem clone would be vulnerable to the

attack of insect pes ts which becom e resis tant to AZ. Multiclonal plantation with other forest trees may therefore be appropriate. The planting should be done

systematically like other forest trees.

10. Economic gains

The price structure of neem-based pesticides is comparable with synthetics and other pesticides. Nevertheless , means to reduce the production cost and selling

price should be searched s o that farmer intends to purchase neem pes ticides. In fact, AZ can contribute about 10% of the value of pesticides us ed in India. It is better

to buy cake or kernel powders than extracts becaus e these natural products are cheap, contain no chemical additives, and have longer shelf life.

The income from neem oil can in the order of 25,000-40,000/tonne and that of cake about 7-8 times les s. Oil processing units can earn Rs . 700-900/ tonne of

kernels for crushing operation. There is an opportunity for new business men to invest in oil processing enterprises. The present oil price ranges between Rs .15-

18/kg and that of cake between Rs. 8-12/10 kg. Neem cake is exported and fetches foreign exchange. The poss ibility of exporting kernels m ay be explored as

collection is eas y and cheap due to low labour cost. The oil or concentrates can be exported in stable formulations . Phytosanitary certificate is a legal obligation.

11. Residue on harvested produce and stored commodities


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People are conscious about the residues in the agricultural produce, organoleptic properties and nutritional qualities (e.g. taste, aroma, texture, appearance, colour,

contents of ash, fibre, fat, proteins, carbohydrates etc.) of raw and finished food products. At present, there are no examples of commodities containing more than

detection lim it of 25 ppm of AZ.

12. Formulations

At present, formulations are based on oil (0.03% AZ) and on kerne l extracts (0.15% AZ). Neem products being natural in ori gin, there is a wide variation in the active

ingredients becaus e their content in plant parts vary considerably, as per growing conditions, plant parts (Ganeshkumar, 1994; Udaiyan et al., 1995; Kumar and

Parmar, 1997a; Venkateshwarlu et al., 1997); drying, processing, extraction procedure etc. (Bambarkar, 1990). The major industrial problem is the standardization of

AZ content in the formulations. At present, some companies claim the purity of AZ up to 98%. Simi larly, with few purification s teps, concentrates contain ing about

50% AZ-A is possib le.

Recently, Ramarethinam (1998) dis puted the formulations bas ed on pu re AZ for integration in IPM because resistance to s uch preparations has already been

reported in insect pests (Isman, 1996). Therefore, oil mus t be mixed in such preparations or oil s hould be the bas ic material because oil contains not only AZ butother principles s uch as, s alanin, nim bin, nimbandiol, epoxyazadiradione, deacetylnimbin, 6-acetylnimbin, nimbinine, meliantriol and different AZ isomers

(Devakumar, Goswami and Mukerjee, 1985; Govindachari, Geetha and Suresh, 1996). This moiety of active principles in oil might act synergistically for exerting a

greater effect on the target pest. For example, addition of neem oil increased the bioefficacy of AZ-based pes ticide Margosan-O by about 62% (Stark and Walter,

1996). Further, salanin and AZ contents of the neem oil were correlated with bioactivity in lepidopterous ins ects (Kumar and Parmar, 1997b). These investigations

clearly suggest that pure AZ per se is not as effective as AZ with other components in oil. This aspect has rather been neglected in recent years as AZ concentration

is onl y considered for better pest control. This will create the problem o f resistance development, pest resurgence and changes in secondary pests.

By increasing or changing the constituent concentrations in comm ercial neem formulations the balance existing between constituents is di sturbed which may affect

product performances and is not advisable (Ramarethinam,. 1998). The identification of enzymes, which produce biologically active principles and s tudies on

structure-bioactivity relationship, would facilitate the development of new generation safe pes ticides.

Ramarethinam (1998) ques tioned whether neem oil can be al lowed as di lute in the preparation of chemical pesticides without insis ting upon additional toxicity data

for such formulations.

13. Health hazards

Unlike synthetics, neem pesticides pos e health hazards though the severity is less and occasions are rare. Handling of neem concentrates (Iaman,1996),

NeemAzal (Senrayan, 1996) has been found to be risky to human health.

The information on human toxicology/poisoning, mutagenicity, metabolism, carcinogenicity, genotoxicity, neurotoxicity, synergism, antagonism, toxicity of birds,

fishes, honeybees, livestock etc. needs to be gathered. The bioass ays are undertaken by some government and p rivate institutions lis ted below:

1. All India Institute of Hygiene and Public Health, 110, Chittaranjan Avenue, Cucutta-700 073.

2. Association of Occupational, Central Secretariat, Siemens Ltd., Kalwa Works, Thane-Belapur Road, Thane-400 601.

3. Department of Forensic Medicine and Toxicology, Lady Harding Medical College, New Delhi-100 004.

4. Fredrick Institute of Plant Protection and Toxicology, Padappai-601 301, Kancheepuram Dist- Tamil Nadu.

5. Haffkine Institute of Training , Research and Testing, Acharya Dhonde Marg, Parel, Mumbai-400 012.

6. Indian Institute of Toxicology, 159, Ganesh Prasad, Sir Bhalchandra Road, Hindu Colony, Dadar, Mumbai- 400 014.

7. Indus trial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow-226 001.

8. Institute for Toxicological Studies (INTOX), 14, Ganesh Siddhi , Ram Mandir Road,Babhai , Borivali (west) Mumbai- 400 091.

9. Jai Research Foundation, P.O.Valvada-396 108, Gujarat.

10. National Chemical Laboratory, Pashan Road, Pune-411 008.

11. National Poisons Information Centre, Department of Pharmacology, All India Institute of Medical Sciences, New Delhi- 110 029.

12. Shriram Institute for Industrial Research, Delhi University Road. New Delhi-110007.

13. Southern Petrochemical Industries Corporation Ltd. SPIC Centre, 97, Mount Road, Guindy, Chennai-600 032.

14. Technical guidance

Demonstrations on farmers fields, technical information through brochures, pamphlets in local languages are lacking. Indian farmers are reluctant to use neem

pesticides s imply because Plant products including neem are not recommended by the extension network of the Ministry of Agriculture and are yet to find a place in

the package of practices. It is important that Neem Pest Management methods are introduced in the Agriculture University curricula.

- NEEM FOUNDATION

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