The present invention relates to a synergistic insecticidal composition intended for protecting plants, crops or seeds against insect damages. Particularly, the present invention relates to a novel synergistic insecticidal composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin; formulation comprising the synergistic composition and methods of preparation of said formulation.
BACKGROUND OF THE INVENTION
It is known that solo formulations of emamectin benzoate, deltamethrin and lambda-cyhalothrin can be employed for controlling animal pests, in particular, insects.
Also, various combinations of emamectin benzoate with other insecticides have been reported. PCT publication no. WO 00/02453 relates to a pesticidal composition comprising emamectin and at least one other pesticide compound selected from a list of 185 compounds. The listed compounds are: Aldicarb; Azinphos-methyl; Benfuracarb; Bifenthrin; Buprofezin; Carbofuran; Carbosulfan; Cartap; Chlorfluazuron; Chlorpyrifos; Cyfluthrin; Lambda-cy-halothrin; Alpha-cypermethrin; zeta-Cypermethrin; Deltamethrin; Diflubenzuron; Endosulfan; Ethiofencarb; Fenitrothion; Fenobucarb; Fenvalerate; Formothion; Methiocarb; Heptenophos; Imidacloprid; Isoprocarb; Methamidophos; Methomyl; Mevinphos; Parathion; Parathion-methyl; Phosalone; Pirimi- carb; Propoxur; Teflubenzuron; Terbufos; Triazamate; Fenobucarb; Tebufenozide; Fipronil; beta-Cyfluthrin; Silafluofen; Fenpyroximate; Pyridaben; Fenazaquin; Pyriproxyfen; Pyrimi- difen; Nitenpyram; NI-25, Acetamiprid; Avermectin; an insectactive extract from a plant; a preparation which contains insect-active nematodes; a preparation obtainable from Bacillus subtilis; a preparation which contains insect-active fungi; a preparation which contains insect-active viruses; AC 303 630; Acephate;

Acrinathrin; Alanycarb; Alphamethrin; Amitraz; AZ 60541; Azinphos A; Azinphos M; Azocyclotin; Bendiocarb; Bensultap; Betacyfluthrin; BPMC; Brofenprox; Bromophos A; Bufencarb; Butocarboxim; Butylpyridaben; Cadusafos; Carbaryl; Carbopheno-thion; Chloethocarb; Chlorethoxyfos; Chlormephos; Cis-Res-methrin; Clocythrin; Clofentezin; Cyanophos; Cycloprothrin; Cyhexatin; Demeton M; Demeton S; Demeton-S-methyl; Dichlofenthion; Dicliphos; Diethion; Dimethoat; Dimethylvinphos; Dioxathion; Edifenphos; Esfenvalerat; Ethion; Ethofenprox; Ethoprophos; Etrimphos; Fenamiphos; Fenbutatinoxid; Fenothiocarb; Fenpropathrin; Fenpyrad; Fenthion; Fluazinam; Flucycloxuron; Flucythrinat; Flufenoxuron; Flufenprox; Fonophos; Fosthiazat; Fubfenprox; HCH; Hexaflumuron; Hexythiazox; Iprobenfos; Isofenphos; Isoxathion; Ivermectin; Lambda- cyhalothrin; Malathion; Mecarbam; Mesulfenphos; Metaldehyd; Metolcarb; Milbemectin; Moxidectin; Naled; NC 184; Omethoat; Oxamyl; Oxydemethon-methyl; Oxydeprofos; Permethrin; Phenthoat; Phorat; Phosmet; Phoxim; Pirimiphos M; Pirimiphos A; Promecarb; Propaphos; Prothiofos; Prothoat; Pyrachlophos; Pyrada-phenthion; Pyresmethrin; Pyrethrum; RH 5992; Salithion; Sebufos; Sulfotep; Sulprofos; Tebufenpyrad; Tebupirimphos; Tefluthrin; Temephos; Terbam; Tetrachlor-vinphos; Thiafenox; Thiodicarb; Thiofanox; Thionazin; Thuringiensin; Tralomethrin; Triarthen; Triazophos; Triazuron; Trichlorfon; Trifiumuron; Trimethacarb; Vamidothion; Xylylcarb; Yl 5301/5302; Zetamethrin; DPX-MP062; RH-2485; D 2341 ; XMC (3,5,-Xy-lyl Methylcarbamat); Chlorfenapyr; or Spinosad.
Chinese patent application CN1524420A relates to an insecticidal compound containing emamectin and at least one pyrethroid compound selected from permethrin, cypermethrin, beta-cypermethrin, cyhalothrin, deltamethrin, bifenthrin, fenvalerate, esfenvalerate, fenpropathrin, b fenpropathrin, etofenprox, flucythrinate, fluvalinate, tefluthrin, tralomethrin and cyfluthrin.
Although combination of various group of insecticides have been reported, still there exists a need to provide a novel and synergistic insecticidal composition having better efficacy in terms of pronounced insecticidal effect at low application

rates or against specific pests. Also there exists a need for novel compositions which also addresses the resistance developed due to continued use of known formulations.
SUMMARY OF THE INVENTION
It has now been found that a composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin act synergistically and are suitable for controlling animal pests. Owing to this synergism, markedly lower amounts of active compound can be used, i.e. the activity of the mixture is greater than the activity of the individual components.
Accordingly, the present invention provides a synergistic insecticidal composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin wherein emamectin benzoate is present in an amount in the range from about 0.1 to 3% w/w, deltamethrin in an amount in the range from about 0.1 to 3% w/w and lambda-cyhalothrin in an amount in the range from about 0.1 to 3% w/w.
In one another embodiment, emamectin benzoate is present in an amount 1.1% w/w, deltamethrin is present in an amount 1.5% w/w and lambda-cyhalothrin is present in an amount 1.5% w/w.
In yet another embodiment, the synergistic insecticidal composition is formulated as Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro-emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) suspension, Tablet (TB), Ultra-low volume (ULV) liquid, Water dispersible granules (WG), Wettable powder (WP), Water

dispersible powder for slurry seed treatment (WS), Water dispersible tablet (WT), a mixed formulation of CS and SC (ZC) or A mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW).
In a preferred embodiment, the synergistic insecticidal composition is formulated as micro-emulsion.
In an embodiment, the synergistic composition further comprises an excipient selected from the group comprising emulsifier, acidifier and solvents.
In another embodiment, the emulsifier comprises 5 to 20% w/w of one or more non-ionic emulsifying agents; and 2 to 10% w/w of one or more anionic emulsifying agents.
In one another embodiment, the non-ionic emulsifying agent is selected from the group comprising styrenated phenol ethoxylate and castor oil ethoxylate.
In yet another embodiment the anionic emulsifying agent is selected from the group comprising phosphate ester and calcium dodecylbenzene sulfonate.
In one another embodiment the acidifier is selected from the group comprising citric acid, fumaric acid, trifluoroacetic acid and combinations thereof, and present in an amount in the range from 0.1 to 1% w/w.
In yet another embodiment the solvent is selected from the group comprising C-9, xylene, toluene, 2-ethyl hexanol, dimethyl sulfoxide, N-methyl-2-pyrrolidone, cyclohexanone and combinations thereof.
DETAILED DESCRIPTION OF THE INVENTION
Discussed below are some representative embodiments of the present invention. The invention in its broader aspects is not limited to the specific details and representative methods. The illustrative examples are described in this section in connection with the embodiments and methods provided. The invention according to its various aspects is particularly pointed out and distinctly claimed in the appended claims read in view of this specification and appropriate equivalents.

It is to be noted that, as used in the specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.
The expression of various quantities in terms of "% w/w" or "%" means the percentage by weight, relative to the weight of the total solution or composition unless otherwise specified.
The term "active ingredient" (A.I.) or "active agent" used herein refers to that component of the composition responsible for control of insect-pests.
As used herein, the expressions "SL formulation", "SC formulation" "WDG or WG formulation" "GR formulation", "DF formulation", "CG formulation", "EC formulation", "EW formulation", "ME formulation", "WP formulation" are the international denominations adopted by the FAO (Food and Agricultural Organization of the United Nations) to designate "soluble liquid", "aqueous suspension concentrate", "water dispersible granules", "granular", "dry flowable", "capsulated granules", "emulsion concentrate", "emulsion", "micro-emulsion" and "wettable powder" respectively.
In accordance with an embodiment of the invention, there is provided a synergistic insecticidal composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin. In an embodiment the present invention provides a synergistic insecticidal composition comprising emamectin benzoate in an amount in the range from about 0.1 to 3% w/w, deltamethrin in an amount in the range from about 0.1 to 3% w/w and lambda-cyhalothrin in an amount in the range from about 0.1 to 3% w/w.
Emamectin benzoate, deltamethrin and lamba-cyhalothrin are prepared by methods known in the art or are commercially obtained.

Emamectin benzoate (IUPAC name: A mixture containing 90% of (10E,UE,16E)-(lR,4S,5'S,6S,6'R,8R,12S,13S,20R,21R,24S)-6'-[(S)-sec-butyl]-21,24-dihydroxy-5 ',11,13,22-tetramethyl-2-oxo-(3,7,19-
trioxatetracyclo[15.6.1.14'8.020'24]pentacosa-10,14,16,22-tetraene-6-spiro-2'-(5',6'-
dihydro-2 77-pyran)-12-yl 2,6-dideoxy-3 -0-methyl-4-0-(2,4,6-trideoxy-3 -O-
methyl-4-methylamino-a-L-/)«-o-hexopyranosyl)-a-L-araZ»/>70-hexopyranoside
benzoate and 10% of(10E,UE,16E)-(lR,4S,5'S,6S,6'R,SR,12S,13S,20R,21R,2AS)-
21,24-dihydroxy-6'-isopropyl-5 ',11,13,22-tetramethyl-2-oxo-3,7,19-
trioxatetracyclo[15.6.1.14'8.020'24]pentacosa-10,14,16,22-tetraene-6-spiro-2'-(5',6'-
dihydro-2 77-pyran)-12-yl 2,6-dideoxy-3 -0-methyl-4-0-(2,4,6-trideoxy-3 -O-
methyl-4-methylamino-a-L-/)«-o-hexopyranosyl)-a-L-araZ»/>70-hexopyranoside benzoate) belongs to the class of avermectin insecticides and is represented by following structure:

It is a produced by bacterium Streptomyces avermitilis and is effective against many insect pests. It acts by stimulating the release of gamma-aminobutyric acid, an inhibitory neurotransmitter, thus finally activating chloride channels. It is a non-systemic insecticide which penetrates leaf tissues by translaminar movement.
Deltamethrin (IUPAC name: (S)-a-cyano-3-phenoxybenzyl (lR,3R)-3-(2,2-
dibromovinyl)-2,2-dimethylcyclopropanecarboxylate; Roth: (S)-a-cyano-3-
phenoxybenzyl (lR)-cis-3-(2,2-dibromovinyl)-2,2-
dimethylcyclopropanecarboxylate) belongs to pyrethroid group of insecticides. It is represented by the following structure:


It is a non-systemic insecticide with contact and stomach action. It prevents the sodium channels from functioning, so that no transmission of nerve impulses can take place.
Lambda-cyhalothrin (IUPAC name: Mixture of (R)-a-cyano-3-phenoxybenzyl (lS,3S)-3-[(Z)-2-chloro-3,3,3-trifluoropropenyl]-2,2-
dimethylcyclopropanecarboxylate and (S)-a-cyano-3-phenoxybenzyl (lR,3R)-3-
[(Z)-2-chloro-3,3,3-trifluoropropenyl]-2,2-dimethylcyclopropanecarboxylate;
Roth: Mixture of (R)-a-cyano-3-phenoxybenzyl (lS)-cis-3-[(Z)-2-chloro-3,3,3-
trifluoropropenyl]-2,2-dimethylcyclopropanecarboxylate and (S)-a-cyano-3-
phenoxybenzyl (lR)-cis-3-[(Z)-2-chloro-3,3,3-trifluoropropenyl]-2,2-
dimethylcyclopropanecarboxylate) belongs to pyrethroid class of insecticides. It is represented by following structure.
It is a non-systemic insecticide with contact and stomach action, and repellent properties. It acts on the nervous system of insects and disturbs the function of neurons by interaction with sodium channel.

In a preferred aspect of the invention, the synergistic insecticidal composition comprises emamectin benzoate in an amount 1.1% w/w, deltamethrin in an amount 1.5% w/w and lambda-cyhalothrin in an amount 1.5% w/w.
The composition of the present invention can be converted into the customary formulations, such as Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro-emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) suspension, Tablet (TB), Ultra-low volume (ULV) liquid, Water dispersible granules (WG), Wettable powder (WP), Water dispersible powder for slurry seed treatment (WS), Water dispersible tablet (WT), a mixed formulation of CS and SC (ZC) or A mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW).
The composition of the present invention further comprises an excipient.
In a preferred embodiment, the synergistic insecticidal composition is formulated as micro-emulsion (ME). The excipients that are used to formulate a micro-emulsion include but not limited to emulsifier, acidifier and solvents.
Micro-emulsions are regarded as one of the most promising pesticide formulations. However, formulation of pesticide micro-emulsions is not simple. Obtaining efficient, scientific and inexpensive formulation is challenging.
Micro-emulsion is defined as a solution of a pesticide with emulsifying agents in a water insoluble organic solvent which will form a solution/emulsion when added to water. Micro-emulsions are thermodynamically stable water-based systems containing a water-insoluble component. This means that within a given set of

conditions, the oil phase is stable and will never separate out. In addition, micro-emulsions are composed of extremely tiny particles (similar to micelles) that can be as small as 0.01 micron. This makes the diluted product transparent because light scattering is reduced. By comparison, most coarse emulsions can have average particle sizes in the order of 1 to 5 microns.
Micro-emulsion formulations offer a number of practical advantages, one of the most important being that they typically remain homogeneous without agitation for long periods of time. In this respect, to the agricultural technician or other user, a micro-emulsion formulation can be handled with the same ease and convenience as a simple aqueous solution.
It is desirable to have an emulsifier in the synergistic insecticidal composition. An emulsifier is a substance that stabilizes an emulsion by increasing its kinetic stability. The emulsifiers can be anionic or non-ionic in character. A combination of non-ionic and anionic emulsifying agents is used in the composition of the present invention. One or more non-ionic emulsifying agents and one or more anionic emulsifying agents may be used in the composition of the present invention. In an aspect, the emulsifier comprises 5 to 20% w/w of one or more non-ionic emulsifying agents; and 2 to 10% w/w of one or more anionic emulsifying agents.
Non limiting examples of non-ionic emulsifying agent that can be employed in present invention are styrenated phenol ethoxylate and castor oil ethoxylate. Non limiting examples of anionic emulsifying agent that can be employed in present invention are phosphate ester and calcium dodecylbenzene sulfonate. Commercially available emulsifiers such as UNITOX-30 and UNITOX-50 may be used in the composition of the present invention.
An acidifier is added to the composition of the present invention to enhance the stability of the formulation and also for standardization of pH. The pH of the composition of the present invention formulated as ME is maintained in the range from 2 to 6.

Non limiting examples of acidifier that can be employed in present invention are citric acid, fumaric acid, trifluoroacetic acid and is present in an amount in the range from 1 to 2% w/w.
Suitable solvents useful in accordance with the invention are C9 aromatic solvents, xylene, toluene, 2-ethyl hexanol, dimethyl sulfoxide (DMSO), cyclohexanone, N-methylpyrrolidone (NMP), butanol and combinations thereof. In a preferable aspect, a combination of two or more solvents are used in the composition of the present invention.
The synergistic composition of the present invention is used to control wide variety of insects, by way of example, Helicoverpa armigera, pink bollworm and Spodoptera litura, lepidoptera, coleoptera, heteroptera, homoptera, thysanoptera, acrididae, locusts, aphids, Colorado beetles, thrips, jassids and whitefly in vegetables, brassicas, fruit, maize, tea, grapes, cotton, cereals, citrus, oilseed rape, soybeans and other crops.
In another aspect, the present invention provides a process for the preparation of micro-emulsion formulation comprising the synergistic composition. Alternatively, the formulation may be prepared by any method known in the art.
The inventors of the present invention have surprisingly found that a composition of the present invention is synergetic in nature. The synergetic composition of the present invention is more effective than their individual counterparts or when two actives are taken together. The synergetic composition of the present invention also makes it possible to use markedly smaller quantities of the active ingredients as compared to their individual counterparts.
The composition of the present invention is effective in controlling wide spectrum of insect pests, delays the emergence of the resistant strains of the insect-pests and achieves effective and economic control of undesired insect-pests. The composition of the present invention is relatively safer to human beings, animals and is non-phytotoxic.

The synergistic composition of the present invention provides a number of other advantages-
• Increased efficacy in comparison to the other formulations tested during the trials.
• Economically beneficial to the farmers as it provides better yield of the crop with reduction in the number of sprays
• Reduced possibility of hazards to the farmers due to occupational exposure because of reduction in the number of sprays and
• Is storage stable
The embodiments of the present invention are more particularly described in the following examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to those of skill in the art. Unless otherwise noted, all parts, percentages and ratios reported in the following examples are on a weight basis and all reagents used in the examples were obtained or are available from the chemical suppliers.
EXAMPLES
The synergistic insecticidal composition of the present invention comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin in the form of micro-emulsion is provided in Table 1. The unit of each component of the composition are expressed in "% w/w" i.e. the percentage by weight, relative to the weight of the total solution or composition.
Table 1: Synergistic insecticidal composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin in the form of micro-emulsion (ME)

S. No. Component Function Quantity (% w/w)
1 Emamectin benzoate Active ingredient 1.10
2 Deltamethrin Active ingredient 1.50

3 Lambda-cyhalothrin Active ingredient 1.50
4 Nonionic emulsifying agent Emulsifier 5-20
5 Anionic emulsifying agent Emulsifier 2-10
6 Citric acid/Fumaric acid Acidifier 0.1-1
7 2-ethyl hexanol/ dimethyl
sulfoxide/N-methyl-2-
pyrrolidone/cyclohexanone Solvent 10-20
8 C-9/xylene/toluene Solvent Q.S
QS: quantity sufficient required to make 100% w/w formulation
Table 2 provides quantities of active ingredients and raw material charged to prepare the synergistic composition of the present invention in ME form. The active ingredients are in technical grade. The entries for active ingredients, emamectin benzoate, deltamethrin and lambda-cyhalothrin in table 2 varies from that of table 1, as the entries in table 1 are for 100% pure compounds whereas the entries in Table 2 are for technical ones with certain percentage of impurities.
Hence, emamectin benzoate 1.1% w/w, deltamethrin 1.5% w/w and lambda-cyhalothrin 1.5% w/w of 100% purity of Table 1 corresponds to emamectin benzoate 1.16 g of 95% purity, deltamethrin 1.54 g of 98% purity and lambda-cyhalothrin 1.57 g of 96% purity of Table 2.
Table 2: Quantities of active ingredients and raw material charged

S.No. Component Function Quantity (g)
1 Emamectin benzoate (basis of 95%) Active ingredient 1.16
2 Deltamethrin (basis of 98%) Active ingredient 1.54
3 Lambda-cyhalothrin (basis Active ingredient 1.57

of 96%)
4 Styrenated phenol ethoxylate Non-ionic emulsifying agent 10.00
5 Castor oil ethoxylate Non-ionic emulsifying agent 10.00
6 Phosphate ester Anionic emulsifying agent 5.00
7 Citric acid Acidifier 0.4
8 N-methyl pyrolidone Solvent 40.00
9 2-ethyl hexanol Solvent 10.00
10 Dimethyl sulfoxide Solvent 10.00
11 C-9 Solvent 10.33
Example 1: Process of preparing synergistic insecticidal composition comprising emamectin benzoate, deltamethrin and lambda-cyhalothrin in ME form
All the components were weighed as per Table 2. In a suitable container, emamectin benzoate (1.16g), deltamethrin (1.54g) and lambda-cyhalothrin (1.57g) and solvents such as N-methyl pyrolidone, 2-ethyl hexanol, dimethyl sulfoxide, C-9 were taken. The mixture was stirred to obtain a homogeneous solution. To the solution, citric acid was added and then a blend of styrenated phenol ethoxylate, castor oil ethoxylate and phosphate ester were added and mixed homogeneously to obtain the title insecticidal composition.
Evaluation of bio-efficacy of the synergistic insecticidal composition
Trials were performed in different agro climatic zones of the country to evaluate the biological efficacy of the synergistic insecticidal composition of present invention (Tl) and reference products (T2 - T7) against borers (Helicoverpa

armigera, Pink Bollworm and Spodoptera litura) and sucking pests (Aphids, Jassids and Whitefly) of cotton.
Table 3 provides treatment details of insecticidal compositions for evaluation of bio-efficacy in cotton against borer complex and sucking pests complex. The evaluation was performed by comparing the synergistic insecticidal composition of the present invention (emamectin benzoate 1.1% + deltamethrin 1.5% + lambda-cyhalothrin 1.5% ME) against the reference products, such as, emamectin benzoate and deltamethrin; deltamethrin and lambda-cyhalothrin; emamectin benzoate and lambda-cyhalothrin; solo formulations of emamectin benzoate, deltamethrin and lambda-cyhalothrin.
Table 3: Treatment details for evaluation of bio-efficacy of the synergistic insecticidal composition

Particulars Treatment Dose
Formulation
g or ml/ha
Tl Emamectin benzoate 1.1% + Deltamethrin 1.5% + Lambda-cyhalothrin 1.5% ME 1000
T2 Emamectin benzoate 5% SG 220
T3 Deltamethrin 1.8% EC 781
T4 Lambda-cyhalothrin 5% EC 500
T5 Emamectin benzoate + Deltamethrin (Tank Mix) 220 + 781
T6 Deltamethrin + Lambda-cyhalothrin (Tank Mix) 781 +500
T7 Emamectin benzoate + Lambda-cyhalothrin (Tank Mix) 220 + 500
T8 Control -

Details of the experiment
The experiment was laid out in Randomized Block Design (RBD) with three replications. The plot size was 100 sq. mts. All the recommended agronomic practices were followed throughout the cropping period. The various insecticidal compositions as per Table 3 were sprayed on cotton crop to evaluate the control of borers (Helicoverpa armigera, Pink Bollworm and Spodoptera litura) and sucking Pests (Aphids, Jassids and Whitefly). Hollow cone nozzle was used for spraying. The spray volume used was 500 litres per hectare. Based on various doses, weighed quantity of test products were dissolved in 5 litres of water/treatment and sprayed uniformly twice at an interval of 10 days.
For borers complex, 10 plants in each treatment were randomly tagged and total damaged balls/10 plant were recorded before the spray and 1 DAT (days after treatment), 3DAT, 7 DAT and 10 DAT of the spray for both the sprays. Mean no. of damaged balls for both the sprays were calculated and expressed in Table 4.
For sucking pests, 10 plants in each treatment were randomly tagged and total number of sucking pest/ per 3 leaves/ 10 plant were recorded before the spray and 1 DAT (days after treatment), 3 DAT, 7 DAT AND 10 DAT of the spray for both sprays. Mean insect population after 2nd spray was calculated and expressed in Table 4.
Table 4: The bio-efficacy effect of different treatments on cotton

Treatment Borers complex % reduction over control Sucking pest complex %
reduction
over control

Mean after 2nd spray*
Mean after 2nd spray**

Tl 1.10 (1.26) 87.36 1.37 (1.37) 89.95
T2 3.60 58.62 9.67 29.05

(2.02) (3.19)
T3 6.30 (2.61) 27.58 6.93
(2.73) 49.16
T4 6.90
(2.72) 20.69 7.46 (2.82) 45.26
T5 2.70 (1.79) 68.96 5.77 (2.50) 57.67
T6 4.80 (2.30) 44.82 5.47 (2.44) 59.86
T7 2.90 (1.84) 66.66 6.10
(2.57) 55.25
T8 8.70 (3.03) ~ 13.63 (3.76) ~
SE(m) 0.20 - 0.29 -
CD. 0.59 - 0.86 -
Figure in parenthesis represents square root transformed value
*(Mean No./per 10 plants) **(Mean No./ per 3 leaves/10
plants)
Synergistic effect of the composition of the present invention
A synergistic effect exists whenever the action of an active ingredient combination is greater than the sum of the actions of the individual components. Synergism was calculated by using Colby's method, Weeds, vol 15 No. l(Jan
1967), pp 20-2.

The synergistic action expected for a given combination of three active components can be calculated as follows:
E = X+Y+Z - {XY+YZ+YZ} + (XYZ)
100 10000
Where E represents expected percentage of insecticidal control for the combination of the three insecticides at defined doses (for example equal to x, y and z respectively), X is the percentage of insecticidal control observed by the compound (I) at a defined dose (equal to x), Y is the percentage of insecticidal control observed by the compound (II) at a defined dose (equal to y), Z is the percentage of insecticidal control observed by the compound (III) at a defined dose (equal to z). When the percentage of insecticidal control observed for the combination is greater than the expected percentage, there is a synergistic effect.
In the same experiment, to evaluate synergistic impact, mean control of both borers and sucking pests were taken for the insecticidal treatments. Table 5 summarizes the synergistic impact of the composition of the present invention.
Table 5: Synergistic impact of the composition of the present invention

Treatment a.i. (g/ha) % Insect control
observed Expected % insect Control Colby Ratio
observed/ expected
Emamectin benzoate + Deltamethrin + Lambda-cyhalothrin ME 11 +
15 +
15 88.66 76.80 1.15
Emamectin benzoate 11 43.84
Deltamethrin 15 38.37
Lambda-cyhalothrin 15 32.97

Emamectin benzoate + Deltamethrin (Tank Mix) 11+15 63.32 65.39 0.97
Deltamethrin + Lambda-cyhalothrin (Tank Mix) 15+15 52.34 58.69 0.89
Emamectin
benzoate + Lambda-
cyhalothrin (Tank Mix) 11+15 60.96 62.36 0.98
Phytotoxicity Observations
For phytotoxicity evaluation on cotton, following observations were made by observing temporary or long lasting damage to the leaves if any viz., leaf injury on tips and leaf surface, wilting, vein clearing, necrosis, epinasty and hyponasty after 2nd spray of the synergistic insecticidal composition of the present invention (Tl). Crop injury was observed on visual rating from 1-10 scale as given in table 6.
Table 6:

Rating Crop Injury (%) Verbal Description
0 - No symptoms
1 1-10 Very slight discoloration
2 11-20 More severe, but not lasting
3 21-30 Moderate and more lasting
4 31-40 Medium and lasting
5 41-50 Moderately heavy
6 51-60 Heavy
7 61-70 Very Heavy

8 71-80 Nearly destroyed
9 81-90 Destroyed
10 91-100 Completely destroyed
Table 7. Phytotoxic effect of synergistic composition of the present invention on cotton

Treatments Phytotoxicity rating

Leaf
tip
injury Wilting Vein Clearing Necrosis Epinasty Hyponasty
Tl 0 0 0 0 0 0
The synergistic insecticidal composition of the present invention gave good control of insects and better economics to farmers as compared to the reference products. Further, the use of the synergistic insecticidal composition resulted in better crop condition, i.e. fresh green leaves and did not produce any phytotoxic symptoms on the plants.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitations with respect to the specific embodiments illustrated is intended or should be inferred. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.

We Claim:

1.A synergistic insecticidal composition comprising:
a) emamectin benzoate,
b) deltamethrin, and
c) lambda-cyhalothrin,
wherein emamectin benzoate is present in an amount in the range from about 0.1 to 3% w/w, deltamethrin is present in an amount in the range from about 0.1 to 3% w/w and lambda-cyhalothrin is present in an amount in the range from about 0.1 to 3% w/w.
2. The synergistic insecticidal composition as claimed in claim 1, wherein emamectin benzoate is present in an amount 1.1% w/w, deltamethrin is present in an amount 1.5% w/w and lambda-cyhalothrin is present in an amount 1.5% w/w.
3. The synergistic insecticidal composition as claimed in claim 1, wherein the composition further comprises an excipient.
4. The synergistic insecticidal composition as claimed in claims 1 to 3, wherein the composition is formulated as Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro-emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) suspension, Tablet (TB), Ultra-low volume (ULV) liquid, Water dispersible granules (WG), Wettable powder (WP), Water dispersible powder for slurry seed treatment (WS), Water

dispersible tablet (WT), a mixed formulation of CS and SC (ZC) or A mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW).
5. The synergistic insecticidal composition as claimed in claims 4, wherein the composition is preferably formulated as micro-emulsion.
6. The synergistic insecticidal composition, as claimed in claims 3 to 5, wherein the excipient is selected from the group comprising emulsifier, acidifier and solvent.
7. The synergistic insecticidal composition as claimed in claim 6, wherein the emulsifier comprises 5 to 20% w/w of one or more non-ionic emulsifying agents; and 2 to 10% w/w of one or more anionic emulsifying agents.
8. The synergistic insecticidal composition as claimed in claim 7, wherein the non-ionic emulsifying agent is selected from the group comprising styrenated phenol ethoxylate and castor oil ethoxylate.
9. The synergistic insecticidal composition as claimed in claim 7, wherein the anionic emulsifying agent is selected from the group comprising phosphate ester and calcium dodecylbenzene sulfonate
10. The synergistic insecticidal composition as claimed in claim 6, wherein the acidifier is selected from the group comprising citric acid, fumaric acid, trifluoroacetic acid and combinations thereof, and present in an amount in the range from 0.1 to 1% w/w.
11. The synergistic insecticidal composition as claimed in claim 6, wherein the solvent is selected from the group comprising C-9, xylene, toluene, 2-ethyl hexanol, dimethyl sulfoxide, N-methyl-2-pyrrolidone, cyclohexanone and combinations thereof.