DESC:FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2016
COMPLETE SPECIFICATION
(See section 10 and rule 13)

TITLE OF THE INVENTION
A SYNERGISTIC HERBICIDE COMPOSITION

APPLICANT
Godrej Agrovet Limited an Indian company, having its address at Godrej One, 3rd Floor, Eastern Express Highway, Vikhroli (East), Mumbai 400079, Maharashtra, India; an Indian Company.

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.
FIELD OF THE INVENTION
[001] The invention relates to herbicidal compositions, more particularly to a broad spectrum synergistic herbicidal formulation and a preparation method thereof.

BACKGROUND OF THE INVENTION
[002] Weeds are plants that are considered undesirable, since they are plants which grow out of place and are not intentionally sowed. Weeds generally do not have any redeeming value as far as food, nutrition or medicinal values are concerned.
[003] Weeds have an accelerated growth mechanism. Thus, when weeds undesirably grow around essential crops and plants they interfere with the essential crops by: competing for resources that the essential crop typically needs, namely direct sunlight, soil nutrients, water, and space for growth; providing hosts and vectors for plant pathogens, giving them greater opportunity to infect and degrade the quality of the desired crops; providing food or shelter for animal pests such as seed-eating birds; offering irritation to skin and/ or digestive tracts of people/ animals, either physical irritation via thorns, prickles, or burs, or chemical irritation via natural poisons or irritants present in the weeds; causing root damage to engineering works such as drains, road surfaces, and foundations, etc.
[004] Weed control is therefore important in agriculture. Methods for weed control include hand cultivation with hoes, powered cultivation with cultivators, smothering with mulch or soil solarization, lethal wilting with high heat, burning, or chemical attack with herbicides.
[005] Accordingly, the agriculture industry uses a wide range of herbicides in order to control weeds which interfere with growth, development, yield and quality of agricultural crops. A wide range of herbicide formulations contain only a single active ingredient and cannot contain two or more active ingredients due to several reasons like adverse reactions, non-synergistic effects, non-compatibility of intermixed ingredients etc.
[006] Therefore, there exists a need for a novel synergistic herbicide composition controlling a wide spectrum of weeds along with low toxicity and chemical stability.

SUMMARY OF THE INVENTION
[007] In one aspect, the present invention discloses a synergistic herbicidal composition comprising a combination of at least two acetolactate synthase inhibitors selected from pyrithiobac acid, its salts or combination thereof and sulfonyl urea.
[008] In another aspect, the present invention relates to a process of preparing the synergistic herbicidal composition of the present invention.
[009] In another aspect, the present invention relates to a method of effective weed control in plants, said method comprising applying to the soil, a plant and/or propagation material thereof, an effective amount of the synergistic herbicidal composition of the present invention.
[010] In yet another aspect, the present invention relates to the use of the synergistic herbicidal composition in weed control in soil, a plant and/or propagation material thereof.

DETAILED DESCRIPTION OF THE INVENTION
[011] 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. An illustrative example is described in this section in connection with the embodiments and methods provided.
[012] It is to be noted that, as used in the specification, 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.
[013] The expression of various quantities in terms of “%” or “% w/w” means the percentage by weight of the total solution or composition unless otherwise specified.
[014] In one aspect, the present invention discloses a synergistic herbicidal composition comprising at least two herbicides for a broad-spectrum control of weeds and a process of preparation thereof. The composition preferably comprises an effective amount of a combination of at least two acetolactate synthase inhibitors selected from pyrithiobac acid, its salts or combination thereof and sulfonyl urea and optionally comprising agrochemically acceptable excipient.
[015] In an embodiment, the herbicidal composition comprises 1 – 40 % w/w of sulfonyl urea based on the total weight of the composition. Sulfonyureas are used as post emergence herbicide known to control broad leaved weeds such as Ambrosia artemisiifolia, Abutilon theophrastii, Chenopodium album, Ipomoea hederacea, Ipomoea lacunose, Xanthium strumarium, Anoda cristata, Datura stramonium, Ipomoea purpurea, Xanthium sp., Cyperus rotundus, Medicago polymorpha, Sesbania spp., Tribulus terrestris, Xanthium italicum, etc. (More than 10 Weed Genera) in various crops including cotton.
[016] In an embodiment, the herbicidal composition comprises sulfonyl urea preferably selected from trifloxysulfuron sodium or pyrazosulfuron ethyl.
[017] In an embodiment, the herbicidal composition comprises 5 – 85 % w/w of pyrithiobac acid or its salts or combination thereof based on total weight of the composition. The pyrothiobac acid and its salts are acetolactate synthase inhibitors used as early post emergence herbicide which controls Trianthema Spp, Amaranthus Spp, Chenopodium Spp, Digera Spp, Celosia argentia weeds (more than 5 weed in cotton).
[018] In a preferred embodiment of the present invention, the herbicidal composition comprises synergistically effective amount of pyrithiobac acid and Pyrazosulfuron Ethyl i.e. 5 – 85 % w/w of pyrithiobac acid and 1 – 40 % w/w Pyrazosulfuron Ethyl based on total wight of the composition.
[019] In yet another preferred embodiment, the herbicidal composition comprises 1 – 25 % w/w of pyrithiobac acid, its salt or combination thereof and 1 – 25 % w/w of Pyrazosulfuron Ethyl based on the total weight of composition to achieve the synergistically effective herbicidal composition.
[020] In an embodiment, the composition optionally comprises agrochemically acceptable excipient selected from the group consisting of, but not limited to, emulsifier, adjuvant, co-solvent, surfactant, aromatic hydrocarbon, polymer, dyes, sand, suspension aids, carriers, solvents, stabilizers, anti-foaming agents, anti-freezing agents, wetting agent, preservatives, antioxidants, colorants, thickeners, solid adherents, inert fillers, dispersing agents, diluents, chelating agents, surfactants, and clays and/or mixtures thereof. The agrochemically acceptable excipients in a pre-determined ratio aids to improve the physical stability and prevents the degradation of the composition leading to long term stability and wide spectrum activity. The employment of excipients used in the composition will depend upon the type of formulation and/or the manner in which the formulation is to be applied by the end user.
[021] In an embodiment the agrochemically acceptable excipients are selected from, but is not limited to, Dialkyl naphthalene sulphonate sodium salt, Condensed methyl naphthalene sulfonate, sodium salt, Modified styrene acrylic polymer, Naphthalene Sulphonate blend, Alkylnaphthalene sulfonate (ANS) condensate, Sodium Polycarboxylate, Sodium salts of methylated dibutylnaphthalene sulfonate, Sodium lignosulphonate, Alkyl Sulfonate, Ammonium sulfate, Lactose Monohydrate, Kaolin (China clay), Precipitated silica, or combination/mixture thereof.
[022] In an embodiment of the invention, the agrochemically acceptable excipients include at least 1 % w/w to10 % w/w based on total weight of the composition, preferably 2 % w/w to 5 % w/w based on total weight of the composition.
[023] In an embodiment, the herbicidal composition can be formulated in any form known to a person skilled in the art selected from the group consisting of, but not limited to, a Soluble liquid(SL), Emulsifiable Concentrate (EC), Granules (GR), suspension concentrate (SC) formulation, Water Dispersible Granules (WG), Wettable Powder (WP), ZC a mixed formulation of capsule suspension (CS) and suspension concentrate (SC), Suspoemulsion (SE), Oil Dispersion(OD), Flowable suspension (FS), water dispersible powder for slurry treatment (WS) or powder for dry seed treatment (DS).
[024] In a preferred embodiment of the present invention, the herbicidal composition is formulated in the form of a Water Dispersible Granules (WG) formulation. Typically, the herbicidal composition in the form of a ready-to use stable Water Dispersible Granules (WG)formulation demonstrates synergistic effects with good physical and chemical stability.
[025] Another aspect of the present invention provides a process of preparing the herbicidal composition of the present invention. The process comprises the following steps:
a. Charging Pyrithiobac Sodium, Pyrazosulfuron Ethyl and agrochemically acceptable excipients to a blender under continuous mixing to get a pre-mix powder;
b. passing the pre-mix powder through air jet mill to reduce the particle size as per requirements;
c. powder from step b) is transferred to post blender for mixing;
d. powder from step c) is transferred to sigma mixer to prepare dough using water/solvent;
e. the dough is then processed through granulation equipment to form granules;
f. granules are dried by using Fluid Bed dryer to obtain herbicidal composition.

[026] In a preferred embodiment, the process comprises the following steps:
a. Charging Kaolin (China clay), Pyrithiobac Sodium, Pyrazosulfuron Ethyl, Dialkyl naphthalene sulphonate sodium salt (Supragil WP), Condensed methyl naphthalene sulfonate, sodium salt (Supragil MNS 90), Ammonium sulfate, Lactose Monohydrate to the ribbon blender under continuous mixing for one hour to get a pre-mix powder;
b. pass the pre-mix powder through air jet mill to reduce the particle size as per requirements;
c. powder from step b) is transferred to post blender (Ribbon blender) for mixing for a period of 2-3 hours;
d. powder from step c) is transferred to sigma mixer to prepare dough using water/solvent;
e. the dough is then processed through granulation equipment (Basket extruder) to form granules;
f. granules are dried by using Fluid Bed dryer to obtain water dispersible granule formulation.
[027] Yet another aspect of the present invention provides a method of effective weed control in plants, said method comprising applying to the soil, a plant and/or propagation material thereof, an effective amount of the synergistic herbicidal composition.
[028] Advantageously, the synergistic herbicidal composition demonstrates broad spectrum control of weed flora in paddy as an early post emergence herbicide to control more than 10 weed genera in various crops including cotton. Accordingly, the herbicidal composition is used to control weed species such as Ambrosia artemisiifolia, Abutilon theophrastii, Chenopodium album, Ipomoea hederacea, Ipomoea lacunose, Xanthium strumarium, Anoda cristata, Datura stramonium, Ipomoea purpurea, Xanthium sp., Cyperus rotundus, Medicago polymorpha, Sesbania spp., Tribulus terrestris, Xanthium italicum, etc.
EXAMPLES
[029] The following examples are illustrative of the present invention but not limitative of the scope thereof:
[030] Materials and Methods
[031] Materials: Pyrithiobac Sodium, Pyrazosulfuron Ethyl, Dialkyl naphthalene sulphonate sodium salt (Supragil WP), Condensed methyl naphthalene sulfonate, sodium salt (Supragil MNS 90), Modified styrene acrylic polymer (Atlox Metasperse 550S), Naphthalene Sulphonate blend (Morwet EFW), Alkylnaphthalene sulfonate (ANS) condensate (Morwet D 425), Sodium Polycarboxylate (Geropon/36), Sodium salts of methylated dibutylnaphthalene sulfonate (Morwet DB), Sodium lignosulphonate (Borresperse NA), Alkyl Sulfonate (Berol 790A), Ammonium sulfate, Lactose Monohydrate, Kaolin (China clay), Precipitated silica.
[032] Method: Herbicidal WG formulations comprising the Pyrithiobac Sodium, Pyrazosulfuron Ethyl and agrochemically acceptable excipients were prepared granulation process as follows: charge Kaolin (China clay), Pyrithiobac Sodium, Pyrazosulfuron Ethyl, Dialkyl naphthalene sulphonate sodium salt (Supragil WP), Condensed methyl naphthalene sulfonate, sodium salt (Supragil MNS 90), Ammonium sulfate, Lactose Monohydrate to the ribbon blender under continuous mixing for one hour to get a pre-mix powder; pass the pre-mix powder through air jet mill to reduce the particle size as per requirements; powder from step b) is transferred to post blender (Ribbon blender) for mixing for a period of 2-3 hours; powder from step c) is transferred to sigma mixer to prepare dough using water/solvent in q.s. to 100% w/w; the dough is then processed through granulation equipment (Basket extruder) to form granules; granules are dried by using Fluid Bed dryer to obtain water dispersible granule formulation.
[033] The composition of herbicidal WG formulation prepared according to the above-described method are provided in Table 1 as follows:
Table 1

S. No. Pyrithiobac Sodium
(% w/w) Pyrazosulfuron ethyl
(% w/w) Adjuvants/
others
(% w/w)
Dose/Ha
(ml)
Formulation Example-1 10 2 88 600
Formulation Example-2 15 3 82 500
Formulation Example-3 20 4 76 300
Formulation Example-4 5 10 85 500
Formulation Example-5 5 15 80 450
Formulation Example-6 5 20 75 600
Formulation
Example -7 2 10 85 500
Formulation
Example-8 3 15 80 450
Formulation
Example-9 4 20 75 600

[034] The amounts of various ingredients used in the herbicidal WG formulations comprising the Pyrithiobac sodium, Pyrazosulfuron Ethyl and agrochemically acceptable excipients is summarized in Table 2-7 below.
[035] Formulation Example-1 (Pyrithiobac Sodium 10% + Pyrazosulfuron Ethyl 2%)

Table 2
Table 2:Component Name % w/w
Pyrithiobac Sodium a.i. 10
Pyrazosulfuron Ethyl a.i. 2
Dialkyl naphthalene sulphonate sodium salt (Supragil WP) 2
Condensed methyl naphthalene sulfonate, sodium salt (Supragil MNS 90) 4
Ammonium sulfate 10
Lactose Monohydrate 10
Kaolin (China clay) q.s. to 100

[036] Formulation Example-2 (Pyrithiobac Sodium 15% + Pyrazosulfuron Ethyl 3%)
Table 3
Component Name % w/w
Pyrithiobac Sodium a.i. 15
Pyrazosulfuron Ethyl a.i. 3
Dialkyl naphthalene sulphonate sodium salt (Supragil WP) 3
Modified styrene acrylic polymer (Atlox Metasperse 550S) 5
Ammonium sulfate 10
Lactose Monohydrate 10
Kaolin (China clay) q.s. to 100

[037] Formulation Example-3 (Pyrithiobac Sodium 20% + Pyrazosulfuron Ethyl 4%)
Table 4
Component Name % w/w
Pyrithiobac Sodium a.i. 20
Pyrazosulfuron Ethyl a.i. 4
Naphthalene Sulphonate blend (Morwet EFW) 3
Alkylnaphthalene sulfonate (ANS) condensate (Morwet D 425) 6
Ammonium sulfate 10
Precipitated silica 5
Kaolin (China clay) q.s. to 100

[038] Formulation Example-4 (Pyrithiobac Sodium 2% + Pyrazosulfuron Ethyl 10%)
Table 5
Component Name % w/w
Pyrithiobac Sodium a.i. 5
Pyrazosulfuron Ethyl a.i. 10
Naphthalene Sulphonate blend (Morwet EFW) 2
Sodium Polycarboxylate (Geropon/36) 5
Ammonium sulfate 10
Precipitated silica 5
Koalin Kaolin (China clay) q.s. to 100

[039] Formulation Example-5 (Pyrithiobac Sodium 3% + Pyrazosulfuron Ethyl 15%)
Table 6
Component Name % w/w
Pyrithiobac Sodium a.i. 5
Pyrazosulfuron Ethyl a.i. 15
Sodium salts of methylated dibutylnaphthalene sulfonate (Morwet DB) 2
Sodium lignosulphonate (Borresperse NA) 5
Ammonium sulfate 10
Lactose Monohydrate 10
Koalin Kaolin (China clay) q.s. to 100

[040] Formulation Example-6 (Pyrithiobac Sodium 4% + Pyrazosulfuron Ethyl 20%)

Table 7

Component Name % w/w
Pyrithiobac Sodium a.i. 5
Pyrazosulfuron Ethyl a.i. 20
Alkyl Sulfonate (Berol 790A) 3
Alkylnaphthalene sulfonate (ANS) condensate (Morwet D 425) 6
Ammonium sulfate 10
Lactose Monohydrate 10
Koalin Kaolin (China clay) q.s. to 100

[041] Efficacy Studies
[042] Field trials were performed to evaluate the efficacy of herbicidal EW formulation described above on annual grass control and dicot control in Cotton perennial crops.
[043] Cotton crops were grown on plots under natural outdoor conditions and the weed flora present in the field were, but not limited to, preferably Ambrosia artemisiifolia, Abutilon theophrastii, Ipomoea hederacea, Ipomoea lacunose, Xanthium strumarium, Anoda cristata, Datura stramonium, Ipomoea purpurea, Xanthium sp., Cyperus rotundus, Medicago polymorpha, Sesbania spp., Tribulus terrestris, Xanthium italicum, Trianthema Spp, Amaranthus Spp, Chenopodium Spp, Digera Spp, Celosia argentia, at the 2-4 leaf stage.
[044] Herbicidal formulations of the invention in different doses as mentioned in Tables 2-4 were diluted with water to get desired solution having actives as presented in Table 8 and sprayed on the cotton crops with weed flora present in the field. Further, Pyrithiobac Sodium and Pyrazosulfuron Ethyl were individually sprayed on the cotton crops with weed flora present in the field.
[045] The application on the cotton crops with weed flora present in the field was preferably as foliar spray at an application rate of 500 liters water per hectare using knapsack sprayer with flat fan nozzle. The number of individual weeds and total weeds present in the field was recorded at 15, 30 and 60 days after the application of the herbicidal formulations of the invention in comparison with untreated control. The total weed control efficacy at 30 days after treatment is shown in Table 8.
[046] Further, Colby's equation was used to determine the herbicidal effects expected from the mixtures. (See Colby, S. R. Calculation of the synergistic and antagonistic response of herbicide combinations. Weeds 1967, 15, 20 - 22.) The following equation was used to calculate the expected activity of mixtures containing two active ingredients, A and B:
Expected = A + B - (A x B/100)
A = observed efficacy of active component A at the same concentration as used in the mixture; B = observed efficacy of active component B at the same concentration as used in the mixture. The ability of the compositions described herein to afford suitable weed control is illustrated by the efficacy data in Table 8.
[047] Total weed control efficacy influenced by various herbicidal WG formulation at 30 days after application in Cotton perennial crops at the 2-4 leaf stage is represented in Table 8 below.

Table 8

Dose rate: gram a.i./ha Total weed control
efficacy at 30 DAT Colby's Difference (O-E) Synergism/ Antagonism/ Additivity
Observed Efficacy in % (O) Calculated Efficacy in % (E)
Pyrithiobac
Sodium Pyrazosulfuron Ethyl
60 0 82 NA NA NA
62.5 0 90 NA NA NA
75 0 93 NA NA NA
0 12 75 NA NA NA
0 15 79 NA NA NA
60 12 98.3 95.5 2.8 Synergism
75 15 99.3 98.53 1.27 Synergism
DAT: Days after treatment

[048] Highest weed control efficiency was recorded with the application of herbicidal WG formulations of the invention as compared to individual application of each active ingredient Pyrithiobac Sodium and Pyrazosulfuron Ethyl. Further, the results clearly show that herbicidal composition according to the present invention demonstrated a synergistic increase in the spectrum of weed control in addition to reducing the time and labour in a weed management program.
[049] Further, the synergistic herbicidal composition exhibits extremely useful weed control efficiency and has no phytotoxic impact on cotton crops.
[050] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.
,CLAIMS:We Claim:
1. A synergistic herbicidal composition comprising a combination of at least two acetolactate synthase inhibitors selected from pyrithiobac acid, its salts or combination thereof and sulfonyl urea.
2. The herbicidal composition as claimed in claim 1, comprising 1 – 40 % w/w of sulfonyl urea and 5 – 85 % w/w of pyrithiobac acid or its salts or combination thereof based on total weight of the composition.
3. The herbicidal composition as claimed in claim 1or 2, wherein the sulfonyl urea is selected from trifloxysulfuron sodium or pyrazosulfuron ethyl.
4. The herbicidal composition as claimed in claim 1, further comprising agrochemically acceptable excipients selected from carrier, defoamer, wetting agent, disintegrating agent, anti-caking agent, dispersing agent, anionic emulsifier, colorant, polymeric film forming agent, non-ionic emulsifier sticking agent, anionic surfactant, non-ionic surfactant, polymeric surfactant, oil, stabilizer, preservative, thickener, viscosity modifying agent, rheology modifying agent, anti-freezing agent, and mixtures thereof.
5. The herbicidal composition as claimed in claim 1, wherein said composition is in form of any of Soluble liquid (SL), Emulsifiable Concentrate (EC), Granules (GR), suspension concentrate (SC) formulation, Water Dispersible Granules (WG), Wettable Powder (WP), ZC a mixed formulation of capsule suspension (CS) and suspension concentrate (SC), Suspoemulsion (SE), Oil Dispersion(OD), Flowable suspension (FS), water dispersible powder for slurry treatment (WS) or powder for dry seed treatment (DS).
6. The herbicidal composition as claimed in claim 1, wherein said composition is in the form of Water Dispersible Granules (WG) formulation.
7. The herbicidal composition as claimed in claim 1, wherein said composition affords control of weeds selected from a group consisting of Ambrosia artemisiifolia, Abutilon theophrastii, Chenopodium album, Ipomoea hederacea, Ipomoea lacunose, Xanthium strumarium, Anoda cristata, Datura stramonium, Ipomoea purpurea, Xanthium sp., Cyperus rotundus, Medicago polymorpha, Sesbania spp., Tribulus terrestris), Xanthium italicum, etc.(More than 10 Weed Genera) in various crops including cotton or combination thereof.
8. A method of effective weed control in plants, said method comprising applying to the soil, a plant and/or propagation material thereof, an effective amount of the synergistic herbicidal composition as claimed in claims 1 to 8.
9. A process of preparing herbicidal composition comprising the following steps:
a. Charging Pyrithiobac Sodium, Pyrazosulfuron Ethyl and agrochemically acceptable excipients to a blender under continuous mixing to get a pre-mix powder;
b. passing the pre-mix powder through air jet mill to reduce the particle size as per requirements;
c. powder from step b) is transferred to post blender for mixing;
d. powder from step c) is transferred to sigma mixer to prepare dough using water/solvent;
e. the dough is then processed through granulation equipment to form granules;
f. granules are dried by using Fluid Bed dryer to obtain herbicidal composition.
10. Use of the synergistic herbicidal composition claimed in claims 1 to 8 for weed control in soil, a plant and/or propagation material thereof.
Dated this 7th day of February 2023.
Godrej Agrovet Limited
By their Agent & Attorney

(Nisha Austine)
of Khaitan & Co
Reg. No. IN/PA-1390