Description:HERBICIDAL COMPOSITION
FIELD OF INVENTION:
The present invention relates to a stable, synergistic herbicidal composition and a process for preparation thereof. Further, the present invention also relates to a method for combating narrow-leaved weeds, broad-leaved weeds and sedges in agricultural crops, particularly in wheat.

BACKGROUND OF THE INVENTION:
Weed control is an important practice for crops growth. The losses caused by weeds in agricultural production environments include reduced crop quality, increased irrigation costs, increased harvesting costs, reduced land value, injury to livestock and crop damage from insects and pests harbored by the weeds. Further, weeds may compete with crop plants for the essential nutrients and may produce toxic or irritant chemicals that cause human or animal health problems. Some of the weed varieties also produce immense quantities of seed or vegetative reproductive parts or both that contaminate agricultural products and perpetuate the species in agricultural land.

The main issue with using herbicides is the emergence of pest resistance to that specific herbicide, necessitating the use of a more concentrated herbicidal formulations. A higher concentration of herbicide may be hazardous to human beings and have negative effects on the environment. In the past, people have explored a variety of alternatives and options to solve this issue, leading to the development of poly herbicides mixtures, the use of non-toxic chemicals, and the development of innovative formulations that deliver an effective amount of the herbicide just where it is needed. However, using a multiple combination of herbicides can be problematic because it is like mixing up a bunch of herbicides with distinct chemical, behavioral, and physical characteristics. Additionally, it presents difficulties for the formulator in terms of the stability and compatibility of each herbicide as well as the excipients utilized in the formulation.

S-metolachlor is a selective herbicide that can control annual grass weeds, yellow nutsedge, and some broadleaf species. S-metolachlor is chemically known as 2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1S)-2-methoxy-1-methylethyl]acetamide, having a chemical structure as below:

S-Metolachlor works by inhibiting the growth of long-chain fatty acids of target weeds. This results in a halt in the growth of seeding shoots which causes the weed to not germinate and sprout out of the soil.

Metribuzin is a synthetic organic compound and widely used herbicide applied in pre-emergence and post-emergence on intensive vegetable crops. Metribuzin is chemically known as 4-amino-6-tert-butyl-3-methylsulfanyl-1,2,4-triazin-5-one, having a chemical structure as below:

It is known for its efficiency and relatively low toxicity. Metribuzin is slightly soluble in water, and slightly soluble in several organic solvents. Metribuzin belongs to Triazinone class of herbicide. The mode of action of Metribuzin is that it acts by inhibiting photosystem II of photosynthesis by disrupting electron transfer. This results in death due to starvation in the target plant.

Pyroxasulfone is a selective herbicide for controlling annual grasses, sedges and annual broadleaf weeds. Pyroxysulfone is chemically known as 3-[[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)pyrazol-4-yl]methylsulfonyl]-5,5-dimethyl-4H-1,2-oxazole, having a chemical structure as below:

Pyroxasulfone is a pre-emergence herbicide that inhibits the synthesis of very-long-chain fatty acids (VLCFA) in plants. It works by interfering with the elongation of C18 chains, which are normally catalyzed by VLCFA elongases.

Hence there is an ever growing need to develop herbicidal combinations that not only provide satisfactory control of weeds in the agricultural fields but also are non-phytotoxic to the treated crops. It must however be appreciated that the process of combining the individual AIs or formulating one or more herbicides in a single composition poses many challenges to the formulator. Major challenges being stability of the co- formulation, decomposition of an active compound, or antagonism of the active compounds, phytotoxicity in the treated crops. Therefore, the process of co-formulating the active ingredients requires rigorous experimentation.

Although the three active ingredients above are individually known herbicides, it has been surprisingly found that applying the herbicidal combination comprising S-metolachlor, Metribuzin and Pyroxasulfone along with vegetable oil at specific weight range results in unexpected broad-spectrum control in wheat crop without any noticeable phytotoxicity.

Some combination formulations are also known in the prior art; however, these do not offer the multiple advantages as offered by the presently claimed herbicidal composition.

Therefore, the present herbicidal combination has been developed to provide superior control of weeds with no crop injury and additionally minimizes the total amount of herbicide being applied to cropland.

OBJECT(S) OF THE INVENTION:
It is an object of the present invention to provide a novel, synergistic, stable herbicidal composition.

It is another object of the present invention to provide an herbicidal composition comprising S-metolachlor, Metribuzin, Pyroxasulfone and Vegetable oil.

It is another object of the present invention to provide a synergistic herbicidal composition for providing a broad-spectrum control of weeds in various agricultural crops, particularly in wheat.

It is yet another object of the present invention to provide an herbicidal composition having enhanced efficacy.

It is another object of the present invention to provide an herbicidal composition for enhancing crop yield without having any phytotoxicity.

It is yet another object of the present invention to provide a process for preparing the synergistic herbicidal composition.

It is yet another object of the present invention to provide a method for combating weeds in agricultural crops without causing substantial harm to the crops.

SUMMARY OF THE INVENTION:
In one aspect, the present invention provides a novel, stable, synergistic, environmentally safe, cost-effective herbicidal composition comprising:
a. S-metolachlor in an amount ranging from 1-15% w/w;
b. Metribuzin in an amount ranging from 5-30% w/w;
c. Pyroxasulfone in amount ranging from 1-15% w/w;
d. Vegetable oil in an amount ranging from 0.1-10% w/w; and
e. at least one agriculturally acceptable excipient.

In another aspect, the present invention provides a process for the preparation of an herbicidal composition, comprising the following steps:
a. obtaining a homogeneous mixture of S-Metolachlor Technical, Metribuzin Technical and Pyroxasulfone Technical;
b. adding dispersing agent and wetting agent along with buffer and binder to the homogenous mixture of step (a);
c. adding filler to the mixture of step (b) and mixing uniformly;
d. grinding the mixture obtained in step (c) in a milling process through ACM (Air Classifying Mill) to obtain a particle having size less than 10 microns;
e. adding vegetable oil to the mass obtained in step (d), followed by blending (Post blending mix) to obtain a homogenous mass;
f. preparing a dough by taking the homogenous mass obtained in step (e);
g. preparing and extruding granules through basket extruder; and
h. drying the granules obtained in step (g) in hot air oven to obtain the wettable granules (WG).

In yet another aspect, the present invention provides a method for controlling undesired weeds in wheat crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising a) a herbicidally effective amount of S-metolachlor, b) a herbicidally effective amount of Metribuzin c) a herbicidally effective amount of Pyroxasulfone and vegetable oil along with at least one agriculturally acceptable excipient.

TECHNICAL ADVANCEMENT OF THE INVENTION:
The herbicidal composition as disclosed in the present invention comprises S-metolachlor, Metribuzin, Pyroxasulfone and vegetable oil as described herein above and has several associated technical advantages including but not limited to:
 synergistic effect
 broad spectrum control in weed management
 reduced AI dosage
 plant health benefits; and
 reduced environmental impact.

DETAILED DESCRIPTION OF THE INVENTION:
Abbreviations
D.M. Demineralised Water
RTU Ready to Use
WG Wettable granules
A.I/a.i Active Ingredient
WC No. of weeds in control plot
WT No. of weeds in treated plot
DAA Days After Application
QS Quantum satis

Those skilled in the art will be aware that the invention described herein is subject to variations and modifications other than those specifically described herein. It is to be understood that the invention described herein includes all such variations and modifications. The invention also includes all such steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and all combinations of any two or more of said steps or features.

Unless otherwise specified, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of the ordinary skill in the art to which the invention belongs. For further guidance, term definitions may be included to better appreciate the teaching of the present invention.

The terminology used, in the present invention, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present invention. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The particular sequence of steps disclosed in the method and process of the present invention is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be taken.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.

As used herein, the term “plant” refers to any plant or part thereof including serial and subterranean parts of the plant. It is contemplated that the parts of the plant may be for example, flowers, fruits or vegetables, shoots, leaves, needles, stalks, stems, fruiting bodies, seeds also roots and that parts of the plants may or may not be attached to the remainder of the plant.

As used herein, the term “weed” refers to the unwanted plant which competes for resources with the crop or plant of interest.

As used herein, the term “herbicide” refers to a substance which adversely affects the existence and growth of the target weed.

As used herein the term “herbicidally effective amount” is that quantity of the herbicide active ingredient, applied in an amount which will provide the required control of weed on commercial crops. The amount is dependent upon many factors including, for example, type of formulations, the crop, weed sought to be controlled and environmental conditions.

As used herein, the term “weight percent”, “wt-%”, “percent by weight”, “% by weight” and variations thereof, refer to the concentration of a substance as the weight of that substance divided by the total weight of the composition and multiplied by 100. It is understood that, as used here, “percent”, “%” and the like are intended to be synonymous with “weight percent”, “wt. %”, etc.

As used herein, the term “agriculturally acceptable excipient” refers to an ingredient, additive, component or supplement, liquid or solid, suitable for incorporation in agricultural compositions.

The details of biological material used in the present invention:

Using vegetable oil in the present herbicidal compositions offered several advantages. Some of these advantages include:

 Biodegradability: Vegetable oils are generally biodegradable, meaning they break down naturally over time. This reduces the accumulation of harmful chemicals in soil and water bodies, promoting environmental health.
 Low Toxicity: Vegetable oils tend to have low toxicity levels compared to synthetic chemicals commonly used in herbicides. This characteristic reduces the risk of harm to non-target organisms, including humans, animals, and beneficial insects.
 Selective Weed Control: Vegetable oil-based herbicides can offer selective weed control, targeting specific types of weeds while sparing desired crops or vegetation. This selectivity minimizes damage to crops.
 Adhesion and Penetration: Vegetable oils can enhance the adhesion and penetration of herbicidal compounds onto plant surfaces. This improves the efficacy of the herbicide by ensuring better coverage and absorption by target weeds, leading to more effective weed control.
 Synergistic Effects: Vegetable oils may enhance the performance of herbicidal compounds through synergistic effects. They help herbicides penetrate plant tissues more effectively and increasing their overall efficacy.
 Reduced Runoff: Vegetable oil-based herbicides can reduce runoff compared to water-soluble herbicides. This helps prevent the contamination of nearby water sources with herbicidal chemicals, preserving aquatic ecosystems and water quality.

These benefits make vegetable oil-based herbicides a promising option for sustainable weed management in agriculture.

The vegetable oil was procured from 4825 Jalan Permatang Pauh, 13400 Butterworth, P.W. Malaysia.

In one aspect, the present invention provides a novel, stable, synergistic, environmentally safe, herbicidal composition comprising:
a. S-metolachlor in an amount ranging from 1-15% w/w;
b. Metribuzin in an amount ranging from 5-30% w/w;
c. Pyroxasulfone in amount ranging from 1-15% w/w;
d. Vegetable oil in an amount ranging from 0.1-10% w/w; and
e. at least one agriculturally acceptable excipient.

In an embodiment of the present invention, S-metolachlor is present in an amount ranging from 1-15% w/w of the composition.

In the preferred embodiment of the present invention, S-metolachlor is present in an amount of 6% w/w of the composition.

In an embodiment of the present invention, Metribuzin is present in an amount ranging from 5-30% w/w of the composition.

In a preferred embodiment of the present invention, Metribuzin is present in amount of 6% w/w of the composition.

In an embodiment of the present invention, Pyroxasulfone is present in an amount ranging from 1-15% w/w of the composition.

In a preferred embodiment of the present invention, Pyroxasulfone is present in an amount of 4.8%w/w of the composition.

In an embodiment of the present invention, said vegetable oil is present in an amount ranging from 0.1-10% w/w of the composition.

In a preferred embodiment of the present invention, said vegetable oil is present in an amount of 0.5% w/w of the composition.

In an embodiment of the present invention, said vegetable oil is selected from the group consisting of olive oil, sunflower oil, canola oil, coconut oil, safflower oil, corn oil, peanut oil, cottonseed oil, palm-kernel oil, and soybean oil.

In an embodiment of the present invention, said agriculturally acceptable excipient is selected from the group consisting of at least one anti-freeze agent, at least one dispersing agent, at least one wetting agent, at least one deformer, at least one buffer, at least one anti-bacterial or biocide, at least one filler, at least one binder, at least one thickener, and a combination thereof.

In a preferred embodiment of the present invention, said agriculturally acceptable excipient is selected from the group consisting of at least one dispersing agent, at least one wetting agent, at least one filler, at least one binder, at least one buffer and a combination thereof.

In an embodiment of the present invention, said dispersing agent is selected from the group consisting of sodium lignosulphonates, sodium naphthalene sulphonate- formaldehyde condensates, aliphatic alcohol ethoxylates, tristyrylphenol ethoxylates potassium salt and esters, ethylene oxide/propylene oxide block copolymers and combination thereof.

In a preferred embodiment of the present invention, said dispersing agent is sodium salt of naphthalene sulfonate condensate.

In an embodiment of the present invention, said dispersing agent is present in amount ranging from 14%-18% w/w of the composition.

In a preferred embodiment of the present invention, said dispersing agent is present in amount of 16% w/w of the composition.

In an embodiment of the present invention, said wetting agent is selected from the group consisting of blend of alkyl naphthalene sulfonate, sodium salt, amine salt of poly aryl phenyl ether phosphate, Sodium laurel sulphate, and poly alkyl aryl ethylene oxide phosphate ester and combination thereof.

In a preferred embodiment of the present invention, said wetting agent is sodium laurel sulphate.

In an embodiment of the present invention, said wetting agent is present in an amount ranging from 2%-6% w/w of the composition.

In a preferred embodiment of the present invention, said wetting agent is present in amount of 3% w/w of the composition.

In an embodiment of the present invention, said filler is selected from the group consisting of ammonium sulfate, urea, sucrose, glucose, diatomite, kaolin, white carbon black, light calcium carbonate, talc, attapulgite, pottery clay, silica, china clay, mineral filler, and combination thereof.

In a preferred embodiment of the present invention, said filler is China clay.
In an embodiment of the present invention, said filler is present in an amount ranging from 35%-45% w/w of the composition.

In a preferred embodiment of the present invention, said filler is present in amount of 36% w/w of the composition.

In an embodiment of the present invention, said binder is selected from the group consisting of Starch paste, lactose, Hydroxypropyl methyl cellulose (HPMC), lactose Polyvinyl Pyrrolidone (PVP), Lactose monohydrate, and combinations thereof.

In a preferred embodiment of the present invention, said binder is lactose.

In an embodiment of the present invention, said binder is present in an amount ranging from 16%-22% w/w of the composition.

In a preferred embodiment of the present invention, said binder is present in amount of 18% w/w of the composition.

In an embodiment of the present invention, said buffer is selected from the group consisting of citric acid, sodium bicarbonate, acetic acid with sodium acetate, ammonium hydroxide with ammonium chloride and combination thereof.

In the preferred embodiment of the present invention, said buffer are sodium bicarbonate and citric acid.

In an embodiment of the present invention, sodium bicarbonate is present in an amount ranging from 0.5%-1.5% w/w.

In a preferred embodiment of the present invention, sodium bicarbonate is present in amount of 1% w/w.

In an embodiment of a present invention, citric acid is present in an amount ranging from 0.1%0.4% w/w.

In a preferred embodiment of the present invention, citric acid is present in amount of 0.2% w/w.

In an embodiment of the present invention, said herbicidal composition is formulated in a form selected from the group comprising water-soluble concentrates (SL), emulsifiable concentrates (EC), emulsions (EW), micro-emulsions (ME), Suspension concentrates (SC), oil-based suspension concentrates (OD), flowable suspensions (FS), wettable granules (WG), water-soluble granules (SG), wettable powders (WP), water-dispersible granule (WDG). water soluble powders (SP), granules (GR), encapsulated granules (CG), fine granules (FG), macrogranules (GG), dry flowables (DF), aqueous suspo-emulsions (SE), capsule suspensions (CS) and microgranules (MG).

In a preferred embodiment of the present invention, said herbicidal composition is in the form of wettable granule (WG).

Dry sprayables can either be wettable powders (WP), wettable granules (WG), also known as water soluble granules (WSG) or water dispersable granules (WDG). WPs are a solid pesticide formulation with talc or clay that is ground into a powder form and applied as suspended particles in water. The powder does not dissolve. The powder particles are simply uniformly spread-out using water as a carrier. They can come in pre-measured packets for a certain volume of water for easy mixing. WP formulations need to be constantly agitated to keep the powder from settling out of suspension.

Wettable granule (WG) formulation, which is a preferred formulation as per present invention has following advantages:
 Wettable granules are easier to handle, and store compared to some other solid formulations like dusts. They are less prone to generating dust during handling, which can be an issue with dust formulations.
 These granules readily disperse in water, forming a stable suspension. This ensures a consistent distribution of the active ingredient when mixed with water for application.
 When properly mixed with water, wettable granules provide uniform coverage over the treated area. This uniformity enhances the efficacy of the agrochemical by ensuring consistent application.
 Wettable granules have additives that enhance their adherence to plant surfaces. This promotes better retention and absorption of the active ingredients, improving efficacy.
 As they are designed for dispersion in water, wettable granules typically have lower environmental impact compared to certain formulations that might contain more volatile ingredients or solvents.
 Wettable granules often have good stability, with longer shelf lives compared to some liquid formulations. This stability helps maintain the effectiveness of the active ingredients over time.
 They are relatively easy to mix with water, requiring minimal agitation for dispersion. This ease of mixing contributes to their convenience during application.

Water dispersible granules (WDGs) are a solid, non-dusty granular formulation which disperses or dissolves quickly when added to water in the spray tank to give a fine particle suspension.

They provide a system for delivering solid active ingredients to a target organism. They allow for the production of highly concentrated formulations which are wettable and easily disintegrated on contact with water. WDGs are an attractive alternative to wettable powder (WP) formulations due to their reduction in dust production.

WGs are a pesticide formulation consisting of granules that dissolve completely in water. Therefore, WGs typically do not necessitate constant agitation unless suggested on the label. These formulations are less messy than WPs and also often come in pre-measured packets for a certain volume of water.

The herbicidal composition of the present invention is a Ready to Use Formulation (RTU). The ready to use formulation has various advantages over the tank mix of the active ingredients. These advantages include very few or no inhalation hazards, easy handling, low chances of sedimentation, being environmentally safer, good efficacy without phytotoxicity, lower transportation costs, and scientific practice as the formulation is prepared after stability and compatibility studies.

In another aspect, the present invention provides a process for the preparation of an herbicidal composition, comprising:
a. obtaining a homogeneous mixture of S-Metolachlor Technical, Metribuzin Technical and Pyroxasulfone Technical;
b. adding dispersing agent and wetting agent along with buffer and binder to the homogenous mixture of step (a);
c. adding filler to the mixture of step (b) and mixing uniformly;
d. grinding the mixture obtained in step (c) in a milling process through ACM (Air Classifying Mill) to obtain a particle having size less than 10 microns;
e. adding vegetable oil to the mass obtained in step (d), followed by blending (Post blending mix) to obtain a homogenous mass;
f. preparing a dough by taking the homogenous mass obtained in step (e);
g. preparing and extruding granules through basket extruder; and
h. drying the granules obtained in step (g) in hot air oven to obtain the wettable granules (WG).

In an embodiment of the present invention, S-metolachlor is present in an amount ranging from 1-15% w/w of the composition.

In the preferred embodiment of the present invention, S-metolachlor is present in an amount of 6% w/w of the composition.

In an embodiment of the present invention, Metribuzin is present in an amount ranging from 5-30% w/w of the composition.

In a preferred embodiment of the present invention, Metribuzin is present in an amount of 6% w/w of the composition.

In an embodiment of the present invention, Pyroxasulfone is present in amount ranging from 1-15% w/w of the composition.

In a preferred embodiment of the present invention, Pyroxasulfone is present in amount of 4.8%w/w of the composition.

In an embodiment of the present invention, said vegetable oil is present an amount ranging from 0.1-10% w/w of the composition.
In a preferred embodiment of the present invention, said vegetable oil is present in an amount of 0.5% w/w of the composition.

In an embodiment of the present invention, said vegetable is selected from the group consisting of olive oil, sunflower oil, canola oil, coconut oil, safflower oil, corn oil, peanut oil, cottonseed oil, palm-kernel oil, and soybean oil.

In an embodiment of the present invention, said dispersing agent is selected from the group consisting of sodium lignosulphonates, sodium naphthalene sulphonate- formaldehyde condensates, aliphatic alcohol ethoxylates, China clay, tristyrylphenol ethoxylates potassium salt and esters, ethylene oxide/propylene oxide block copolymers and combination thereof.

In a preferred embodiment of the present invention, said dispersing agent is sodium salt of naphthalene sulfonate condensate.

In an embodiment of the present invention, said dispersing agent is present in amount ranging from 14%-18% w/w of the composition.

In a preferred embodiment of the present invention, said dispersing agent is present in amount of 16% w/w of the composition.

In an embodiment of the present invention, said wetting agent is selected from the group consisting of f blend of alkyl naphthalene sulfonate, sodium salt, amine salt of poly aryl phenyl ether phosphate, Sodium laurel sulphate, and poly alkyl aryl ethylene oxide phosphate ester. and combination thereof.

In a preferred embodiment of the present invention, said wetting agent is sodium laurel sulphate.

In an embodiment of the present invention, said wetting agent is present in an amount ranging from 2%-6% w/w of the composition.

In a preferred embodiment of the present invention, said wetting agent is present in amount of 3% w/w of the composition.
In a preferred embodiment of the present invention, said buffer is sodium bicarbonate and citric acid.

In an embodiment of the present invention, said buffer is selected from the group consisting of citric acid, sodium bicarbonate, acetic acid with sodium acetate, ammonium hydroxide with ammonium chloride and combination thereof.

In the preferred embodiment of the present invention, said buffer are sodium bicarbonate and citric acid.

In an embodiment of the present invention, sodium bicarbonate is present in an amount ranging from 0.5%-1.5% w/w.

In a preferred embodiment of the present invention, sodium bicarbonate is present in amount of 1% w/w.

In an embodiment of a present invention, citric acid is present in an amount ranging from 0.1%0.4% w/w.

In a preferred embodiment of the present invention, citric acid is present in amount of 0.2% w/w.

In an embodiment of the present invention, said binder is selected from the group consisting of lactose, silica, alumina, water glass, phosphate binders and combination thereof.

In a preferred embodiment of the present invention, said binder is lactose.

In an embodiment of the present invention, said binder is present in an amount ranging from 16%-22% w/w of the composition.

In a preferred embodiment of the present invention, said binder is present in amount of 18% w/w of the composition.

In an embodiment of the present invention, said filler is selected from the group consisting of ammonium sulfate, urea, sucrose, glucose, diatomite, kaolin, white carbon black, light calcium carbonate, talc, attapulgite, pottery clay, silica, china clay, mineral filler, and combination thereof.

In a preferred embodiment of the present invention, said fillers are silica and china clay.

In an embodiment of the present invention, silica is present in an amount ranging from 6%-10% w/w.

In a preferred embodiment of the present invention, silica is present in amount of 8% w/w.
In an embodiment of the present invention, China clay is present in an amount ranging from 35%-45% w/w of the composition.

In a preferred embodiment of the present invention, China clay is present in amount of 36% w/w of the composition.

In an embodiment of the present invention, said particle size obtained in the process is less than 10µ through ACM (Air Classifying mill), which is a mill with integrated grinding, classifying, conveying, and collecting operations for achieving ultra-fine grinding.

In the preferred embodiment of the present invention, said particle size obtained in the process is in the range of 0.5-0.8µ.

A particle size range of 0.5-0.8µ in herbicidal compositions, particularly in water-dispersible granule (WG) formulations, can offer several advantages:

 Enhanced Surface Area: Particles in the 0.5-0.8µ size range have a relatively high surface area to volume ratio. This increased surface area allows for better contact and interaction between the herbicidal active ingredients and the target vegetation, leading to improved efficacy.
 Improved Dispersion and Suspension: Particles within this size range disperse more easily in water due to their small size and increased surface area. They form stable suspensions with minimal settling, ensuring uniform distribution of the herbicide throughout the spray solution.
 Increased Penetration: Fine particles in the 0.5-0.8µ range can penetrate plant tissues more effectively, facilitating the absorption of herbicidal compounds into the target weeds or vegetation. This results in enhanced systemic action and better control of unwanted plant growth.
 Reduced Drift: Particles in this size range are less prone to drifting during application compared to finer particles. They exhibit better settling properties and are less likely to become airborne, reducing the risk of off-target damage to nearby crops, vegetation, and the environment.
 Improved Environmental Fate: Fine particles in the 0.5-0.8µ size range are less likely to leach or runoff into water bodies or soil compared to larger particles. This reduces the potential for environmental contamination and minimizes the risk of adverse impacts on aquatic ecosystems and non-target organisms.
 Enhanced Absorption and Translocation: Fine particles can adhere more effectively to plant surfaces and facilitate the absorption and translocation of herbicidal active ingredients within the plant. This ensures thorough and systemic control of weeds or unwanted vegetation, even in hard-to-reach areas.

Utilizing particles within this size range can enhance the overall performance and efficacy of herbicides while minimizing adverse effects on the environment and non-target organisms.
In yet another aspect, the present invention provides a method for controlling undesired weeds in wheat crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising a) a herbicidally effective amount of S-metolachlor, b) a herbicidally effective amount of Metribuzin c) a herbicidally effective amount of Pyroxasulfone and vegetable oil along with at least one agriculturally acceptable excipient.

In an embodiment of the present invention, said a herbicidally effective amount of S-metolachlor is present in the range of 1-15% w/w, b) said herbicidally effective amount of Metribuzin is present in the range of 5-30% w/w c) said herbicidally effective amount of Pyroxasulfone is present in the range of 1-15% w/w and said vegetable oil is present in the range of 0.1-10% w/w.

In a preferred embodiment of the present invention, said a herbicidally effective amount of S-metolachlor is 6% w/w, b) said herbicidally effective amount of Metribuzin is 6% w/w c) said herbicidally effective amount of Pyroxasulfone is 4.8% w/w and said vegetable oil is in an amount of 0.5% w/w.

In an embodiment of the present invention, said vegetable oil is selected from the group consisting of olive oil, sunflower oil, canola oil, coconut oil, safflower oil, corn oil, peanut oil, cottonseed oil, palm-kernel oil, and soybean oil.

In a preferred embodiment of the present invention, said agriculturally acceptable excipient is selected from the group consisting of at least one dispersing agent, at least one wetting agent, at least one filler, at least on buffer, at least one binder, and a combination thereof.

In an embodiment of the present invention, said dispersing agent is selected from the group consisting of sodium lignosulphonates, sodium naphthalene sulphonate- formaldehyde condensates, aliphatic alcohol ethoxylates, China clay, tristyrylphenol ethoxylates potassium salt and esters, ethylene oxide/propylene oxide block copolymers and combination thereof.

In a preferred embodiment of the present invention, said dispersing agent is sodium salt of naphthalene sulfonate condensate.

In an embodiment of the present invention, said dispersing agent is present in amount ranging from 14%-18% w/w of the composition.

In a preferred embodiment of the present invention, said dispersing agent is present in amount of 16% w/w of the composition.

In an embodiment of the present invention, said wetting agent is selected from the group consisting of blend of alkyl naphthalene sulfonate, sodium salt, amine salt of poly aryl phenyl ether phosphate, Sodium laurel sulphate, and poly alkyl aryl ethylene oxide phosphate ester and combination thereof.

In a preferred embodiment of the present invention, said wetting agent is sodium laurel sulphate.
In an embodiment of the present invention, said wetting agent is present in an amount ranging from 2%-6% w/w of the composition.

In a preferred embodiment of the present invention, said wetting agent is present in amount of 3% w/w of the composition.

In an embodiment of the present invention, said filler is selected from the group consisting of ammonium sulfate, urea, sucrose, glucose, diatomite, kaolin, white carbon black, light calcium carbonate, talc, attapulgite, pottery clay, silica, china clay, mineral filler, and combination thereof.

In a preferred embodiment of the present invention, said filler is China clay.

In an embodiment of the present invention, said filler is present in an amount ranging from 35%-45% w/w of the composition.

In a preferred embodiment of the present invention, said filler is present in amount of 36% w/w of the composition.

In an embodiment of the present invention, said binder is selected from the group consisting of Starch paste, lactose, Hydroxypropyl methyl cellulose (HPMC), lactose Polyvinyl Pyrrolidone (PVP), Lactose monohydrate, and combinations thereof.

In a preferred embodiment of the present invention, said binder is lactose.

In an embodiment of the present invention, said binder is present in an amount ranging from 16%-22% w/w of the composition.

In a preferred embodiment of the present invention, said binder is present in amount of 18% w/w of the composition.

In an embodiment of the present invention, said buffer is selected from the group consisting of citric acid, sodium bicarbonate, acetic acid with sodium acetate, ammonium hydroxide with ammonium chloride and combination thereof.
In a preferred embodiment of the present invention, said buffers are sodium bicarbonate and citric acid.

In an embodiment of the present invention, sodium bicarbonate is present in an amount ranging from 0.5%-1.5% w/w.

In a preferred embodiment of the present invention, sodium bicarbonate is present in amount of 1% w/w.

In an embodiment of a present invention, citric acid is present in an amount ranging from 0.1%0.4% w/w.

In a preferred embodiment of the present invention, citric acid is present in amount of 0.2% w/w.

In a preferred embodiment of the present invention, said herbicidal composition is in the form of wettable granule (WG).

Surprisingly it was observed by the inventors that the present composition provides a superior and a broad spectrum of control of weeds at much lower levels of active ingredient combination as compared to what is achieved when the active ingredients are applied alone. Further, it was observed that the application of the presently disclosed herbicidal composition not only achieves effective control of narrow leaved, broad leaved weeds and sedges but also results in substantial improvement in germination and crop vigor.

In an embodiment of the present invention, the herbicidal composition actives exhibit synergistic effect in control of narrow leaved weeds, broad leaved weeds and sedges in agricultural crops, particularly in wheat.

The herbicidal composition of the present invention has an outstanding herbicidal activity against monocotyledonous and dicotyledonous weeds, the tolerant, or cross-tolerant, cereal plants such as wheat, rye, barley, oats etc.

In an embodiment, the herbicidal composition of the present invention effectively controls weeds including but not limited to Phalaris minor, Chenopodium album, Rumex, Fumaria, Malwa spp.,Coronopus spp., Avena fatua, Poa annua, Echinochloa crus-galli, Taraxacum officinale, Plantago major, Cyperus esculentus or Cyperus rotundus.

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present invention. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present invention, and all such modifications are considered to be within the scope of the present invention.
The present invention is further described in light of the following experiments which are set forth for illustration purposes only and not to be construed for limiting the scope of the invention. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXAMPLES:

The examples below are given solely for the purpose of illustration and are not to be construed as limitations of the present invention, as many variations thereof are possible without departing from the spirit and scope of the invention.

Example 1: Preparation of herbicidal composition as a wettable granule

Table 1: Chemical composition of the present invention (in wt. percentage range)
S No. Component Name Content %
1 S-Metolachlor (Basis of 100%) 6.0
2 Metribuzin (Basis of 100%) 6.0
3 Pyroxasulfone (Basis of 100%) 4.8
4 Vegetable oil (Basis of 100%) 1.0
5 Dispersing agent (sodium salt of naphthalene sulfonate condensate) 16
6 Wetting agent (sodium laurel sulphate) 3.0
7 Buffer (sodium bicarbonate 1.0
8 Binder (Lactose) 18.0
9 Filler (precipitate silica) 8.0
10 Buffer (citric acid) 0.2
11 Filler (China Clay) 36
Total Quantity 100

Preparation method of WG formulation is described below:

Steps for preparation-
Step 1: Required amount of S-Metolachlor Technical, Metribuzin Technical & Pyroxasulfone Technical were taken.
Step 2: Dispersing agent and wetting agent were then added along with buffer and binder.
Step 3: Fillers were added and mixed uniformly.
Step 4: The material was ground in a milling process through ACM.
Step 5: Vegetable oil was added to the mass and followed by blending (Post blending mix) to obtain a homogenous mass.
Step 6: Dough was prepared from the material so obtained.
Step 7: Granules were prepared and extruded by basket extruder.

Example 2: Field evaluation of the bio efficacy of the present herbicidal composition
Location/season/crop:
The presently disclosed herbicidal mixture coded as CH-66485 W was tested for its bioefficacy against narrow leaved weeds, broad- leaved weeds and sedges in wheat crop. The trial was conducted during the Rabi season 2022 at Karnal, Haryana on HD-2967 variety of wheat.

Trial layout:
The plants were aligned in a plot size of 50 sqm, with a spacing of 10 cm between individual crop plants and the same spacing of 10 cm between the rows. The trial was laid out in a random block design consisting of a total of 13 treatments in three replications.

Climatic conditions: The trial was conducted at a temp. of 21℃ under 86% relative humidity and no winds.

Application: The application of the herbicidal trimix was carried out at pre-emergence stage from 0-3 days after sowing and at 2-4 leaves stage of weed.

Measured quantity of the chemical was added to required volume of water @ 375 lit. /ha for spray. The spray tank was filled with ½ the quantity of clean required volume of water and then the measured chemical (according to the dose) was added followed by the rest half quantity of water. The solution was stirred well before application. Knapsack sprayer fitted with boom along with flood jet nozzle was used to apply the herbicidal composition.

Table 2: Treatment details
Treatments Product a.i./Ha Dose/Ha
T-1 Untreated
T-2 CH-6648 WG 131.25 + 131.25 + 105 2250 gm
T-3 CH-6648 WG 150 + 150 + 120 2500 gm
T-4 CH-6648 WG 169 + 169 + 135 2750 gm
T-5 CH-66485 WG 131.25 + 131.25 + 105 + 11.25 2250 gm
T-6 CH-66485 WG 150 + 150 + 120 + 12.5 2500 gm
T-7 CH-66485 WG 169 + 169 + 135 + 13.75 2750 gm
T-8 Metribuzin 70 WP 175 250 gm
T-9 Pyroxasulfone 85 WG 127.5 150 gm
T-10 S- Metolachlor 50 EC 150 300

Note:

CH-6648 WG S-metolachlor 6 % + Metribuzin 6 % + Pyroxasulfone 4.8 % WG
CH-66485 WG S-metolachlor 6 % + Metribuzin 6 % + Pyroxasulfone 4.8 % + Vegetable oil 0.5 % WG

Evaluation of Bio efficacy

Weed count: A quadrate (0.5m × 0.5m) was placed at 3 randomly selected places in all the plots of the experimental field and the number of weed flora were counted uniformly at 14 Days after 1st irrigation and 28 days after 1st irrigation after application.
Weed control: The weed control was calculated based on no. of live weed flora at 14 Days after 1st irrigation and 28 days after 1st irrigation.

Percent weed control = WC – WT
…………. × 100
WC

Where, WC= No. of weed in control plot
WT= No. of weed in treated plot

Observations:
Table-3 (a): Effect of herbicidal treatment on weed density of narrow leaves & Broad leaves weeds 14 DAA:

Treatments Product A.I./Ha Dose/Ha (gm) Phalaris minor % Control Chenopodium album % Control Fumaria spp. % Control Coronopus Spp. % Control
T-1 Untreated 24 0.00 15 0.00 14 0.00 19 0.00
T-2 CH-6648 WG 131.25 + 131.25 + 105 2250 gm 7 70.83 6 60.00 6 57.14 5.5 71.05
T-3 CH-6648 WG 150 + 150 + 120 2500 gm 4 83.33 4 73.33 3 78.57 5.3 72.11
T-4 CH-6648 WG 169 + 169 + 135 2750 gm 3.5 85.42 3.9 74.00 3.1 77.86 5 73.68
T-5 CH-66485 WG 131.25 + 131.25 + 105 + 11.25 2250 gm 4.5 81.25 4.5 70.00 1.5 89.29 3.5 81.58
T-6 CH-66485 WG 150 + 150 + 120 + 12.5 2500 gm 2.5 89.58 2.1 86.00 1.2 91.43 2.3 87.89
T-7 CH-66485 WG 169 + 169 + 135 + 13.75 2750 gm 2.3 90.42 2 86.67 1.1 92.14 2.2 88.42
T-8 Metribuzin 70 WP 175 250 gm 12 50.00 6 60.00 8 42.86 6.5 65.79
T-9 Pyroxasulfone 85 WG 127.5 150 gm 7.5 68.75 10 33.33 5 64.29 7 63.16

T-10 S- Metolachlor 50 EC 150 300 13 45.83 6.5 56.67 3.5 75.00 8 57.89
As seen in table 3(a), treatment with S-metolachlor alone a dosage of 150g ai/ha results in 45.83% control against Phalaris minor (narrow leaved weeds), 56.67% control against Chenopodium album (broad leaved weeds), 75% control against Fumaria spp. (Broad leaved weeds) and 57.89% control against Cornonopuss spp. (narrow leaved weeds) after 14 days of application. Treatment with Metribuzin alone at a dosage of 175 g ai/ha results in 50% control against Phalaris minor (narrow leaved weeds), 60% control against Chenopodium album (broad leaved weeds), 43% control against Fumaria spp. (Broad leaved weeds) and 66% control against Cornonopuss spp. (narrow leaved weeds) after 14 days of application Treatment with Pyroxasulfone alone at a dosage of 127.5g/ha results in 69% control against Phalaris minor (narrow leaved weeds), 33% control against Chenopodium album (broad leaved weeds), 64% control against Fumaria spp. (Broad leaved weeds) and 63% control against Cornonopuss spp. (narrow leaved weeds) after 14 days of application However, unexpectedly and surprisingly, advantageously, the combination of S-metolachlor, Metribuzin, Pyroxasulfone and vegetable oil results in about 90% control against Phalaris minor (narrow leaved weeds), 86% control against Chenopodium album (broad leaved weeds), 91% control against Fumaria spp. (Broad leaved weeds) and 88% control against Cornonopuss spp. (narrow leaved weeds) after 14 days of application with reduced concentration of the active ingredients. Thus, the efficacy achieved with the combination is superior to solo applications of active ingredients at a comparatively lower dosage.

Further, as seen in the table above, the combination of S-metolachlor, Metribuzin, and Pyroxasulfone (without vegetable oil) results in about 83% control against Phalaris minor (narrow leaved weeds), 73% control against Chenopodium album (broad leaved weeds), 78% control against Fumaria spp. (Broad leaved weeds) and 72 % control against Cornonopuss spp. after 14 days of application. However, unexpectedly and surprisingly, advantageously, the combination of S-metolachlor, Metribuzin, Pyroxasulfone and vegetable oil results in about 90% control against Phalaris minor (narrow leaved weeds), 86% control against Chenopodium album (broad leaved weeds), 91% control against Fumaria spp. (Broad leaved weeds) and 88% control against Cornonopuss spp. (narrow leaved weeds) after 14 days of application This leads to the conclusion that addition of vegetable oil contributes to the synergy and better efficacy of the herbicidal combination.

Table-3 (b): Effect of herbicidal treatment on weed density of narrow leaves & Broad leaves weeds 28 DAA:

Treatments Product A.I/ha Dose/ha Phalaris minor %
Control Chenopodium album % Control Fumaria spp. % Control Coronopus Spp. %
Control
T-1 Untreated 29 0.00 17 0.00 16 0.00 21 0.00
T-2 CH-6648 WG 131.25 + 131.25 + 105 2250 gm 7 75.86 6 64.71 7 56.25 5.8 72.38
T-3 CH-6648 WG 150 + 150 + 120 2500 gm 6.5 77.59 4 76.47 4 75.00 5.7 72.86
T-4 CH-6648 WG 169 + 169 + 135 2750 gm 6.3 78.28 3.9 77.06 3.7 76.88 5.6 73.33
T-5 CH-66485 WG 131.25 + 131.25 + 105 + 11.25 2250 gm 4.5 84.48 2.9 82.94 1.8 88.75 3.7 82.38
T-6 CH-66485 WG 150 + 150 + 120 + 12.5 2500 gm 2.5 91.38 2.1 87.65 1.4 91.25 2.8 86.67
T-7 CH-66485 WG 169 + 169 + 135 + 13.75 2750 gm 2.3 92.07 2 88.24 1.3 91.88 2.6 87.62
T-8 Metribuzin 70 WP 175 250 gm 12.5 56.90 8 52.94 8.4 47.50 6.5 69.05
T-9 Pyroxasulfone 85 WG 127.5 150 gm 11 62.07 11 35.29 5.3 66.88 7.2 65.71
T-10 S- Metolachlor 50 EC 150 300 14 51.72 8 52.94 3.7 76.88 8.7 58.57

As seen in table 3(b), treatment with S-metolachlor at a dosage of 150g ai/ha alone results in 51% control against Phalaris minor (narrow leaved weeds), 53% control against Chenopodium album (broad leaved weeds), 77% control against Fumaria spp. (Broad leaved weeds) and 86% control against Cornonopuss spp. (narrow leaved weeds) after 28 days of application. Treatment with Metribuzin alone at a dosage of 175g ai/ha results in 57% control against Phalaris minor (narrow leaved weeds), 53% control against Chenopodium album (broad leaved weeds), 47% control against Fumaria spp. (Broad leaved weeds) and 69% control against Cornonopuss spp. (narrow leaved weeds) after 28 days of application Treatment with Pyroxasulfone at a dosage of 127.5g ai/ha alone results in 62% control against Phalaris minor (narrow leaved weeds), 35% control against Chenopodium album (broad leaved weeds), 77% control against Fumaria spp. (Broad leaved weeds) and 58% control against Cornonopuss spp. (narrow leaved weeds) after 28 days of application However, unexpectedly and surprisingly, advantageously, the combination of S-metolachlor, Metribuzin, Pyroxasulfone and vegetable oil results in 91% control against Phalaris minor (narrow leaved weeds), 88% control against Chenopodium album (broad leaved weeds), 91% control against Fumaria spp. (Broad leaved weeds) and 87% control against Cornonopuss spp. (narrow leaved weeds) after 28 days of application at comparatively reduced concentration of the active ingredients. Thus, the results obtained were superior to the solo application of active ingredients.
Further, as seen in the table above, the combination of S-metolachlor, Metribuzin, and Pyroxasulfone without the vegetable oil results in about 77% control against Phalaris minor (narrow leaved weeds), 76% control against Chenopodium album (broad leaved weeds), 75% control against Fumaria spp. (Broad leaved weeds) and 73% control against Cornonopuss spp after 28 days of application. However, unexpectedly and surprisingly, advantageously, the combination of S-metolachlor, Metribuzin, Pyroxasulfone and vegetable oil results in 91% control against Phalaris minor (narrow leaved weeds), 88% control against Chenopodium album (broad leaved weeds), 91% control against Fumaria spp. (Broad leaved weeds) and 87% control against Cornonopuss spp. (narrow leaved weeds) after 28 days of application at reduced concentration of the active ingredients. This lead the inventors to conclude that the addition of vegetable oil contributes to the synergy and better efficacy of the herbicidal combination.

Example 3: Evaluation of Phytotoxicity

Visual observations were recorded at 3, 7 and 10 days after application (DAA) of testing products. The parameters were observed leaf injury on tip/surface, necrosis, vein clearing, epinasty, hyponasty and wilting. The score scale (1-10) followed for leaf injury on tips/surface is given.

Table 4: Phytotoxicity symptoms scoring and rating for leaf injury on tip/surface:
Leaf injury on tips/surface Rating
0-10% 1
11-20% 2
21-30% 3
31-40% 4
41-50% 5
51-60% 6
61-70% 7
71-80% 8
81-90% 9
91-100% 10

Table 5: The Observation were recorded as given below
Treatments Product A.I./Ha Dose/Ha Necrosis

Burning

Stunting

T-1 Untreated - - 3 DAA 7 DAA 10 DAA 3 DAA 7 DAA 10 DAA 3 DAA 7 DAA 10 DAA
T-2 CH-6648 WG 131.25 + 131.25 + 105 2250 gm 0 0 0 c 0 0 0 0 0
T-3 CH-6648 WG 150 + 150 + 120 2500 gm 0 0 0 0 0 0 0 0 0
T-4 CH-6648 WG 169 + 169 + 135 2750 gm 0 0 0 0 0 0 0 0 0
T-5 CH-66485 WG 131.25 + 131.25 + 105 + 11.25 2250 gm 0 0 0 0 0 0 0 0 0
T-6 CH-66485 WG 150 + 150 + 120 + 12.5 2500 gm 0 0 0 0 0 0 0 0 0
T-7 CH-66485 WG 169 + 169 + 135 + 13.75 2750 gm 0 0 0 0 0 0 0 0 0
T-8 Metribuzin 70 WP 175 250 gm 0 0 0 0 0 0 0 0 0
T-9 Pyroxasulfone 85 WG 127.5 150 gm 0 0 0 0 0 0 0 0 0
T-10 S- Metolachlor 50 EC 150 300 0 0 0 0 0 0 0 0 0

As seen in Table 5 there is no phytotoxicity associated with treatment of any of the ingredients to the crop, suggesting that said composition is crop safe. The present invention provides a novel and synergistic combination of S-metolachlor + Metribuzin + Pyroxasulfone + Vegetable oil, which significantly enhances the economic value of crops.

While the present specification discloses a concentrations range across which surprising results are seen, in particular, the combination of S-metolachlor + Metribuzin + Pyroxasulfone + Vegetable oil at concentration of 150g a.i/ha + 150g a.i/ha + 120g a.i/ha + 12.5g a.i/ha respectively shows the best results in controlling the weeds of all types. Thus, there is a clear and significant enhancement in efficacy as compared to solo application of actives which is unexpected and surprising.
, Claims:We Claim:
1. An herbicidal composition comprising:
a. S-metolachlor in an amount ranging from 1-15% w/w;
b. Metribuzin in an amount ranging from 5-30% w/w;
c. Pyroxasulfone in an amount ranging from 1-15% w/w;
d. Vegetable oil in an amount ranging from 0.1-10% w/w; and
e. at least one agriculturally acceptable excipient.

2. The herbicidal composition as claimed in claim 1, wherein said vegetable oil is selected from the group consisting of olive oil, sunflower oil, canola oil, coconut oil, safflower oil, corn oil, peanut oil, cottonseed oil, palm-kernel oil, and soybean oil.

3. The herbicidal composition as claimed in claim 1, wherein said agriculturally acceptable excipient is selected from the group consisting of at least one dispersing agent, at least one wetting agent, at least one filler, at least one buffer, at least one binder, and a combination thereof.

4. The herbicidal composition as claimed in claim 3, wherein said dispersing agent is present in an amount ranging from 14-18% w/w, wetting agent is present in an amount ranging from 2-6% w/w, filler is present in amount ranging from 35-45% w/w, buffer is present in an amount of 0.5-1.5% w/w binder is present in an amount of 16-22% w/w, and a combination thereof.

5. The herbicidal composition as claimed in claim 4, wherein said dispersing agent is present in an amount 16% w/w, wetting agent is present in an amount of 3% w/w, filler is present in amount of 36% w/w, buffer is present in an amount of 1.2% w/w binder is present in an amount of 18% w/w, and a combination thereof.

6. The herbicidal composition as claimed in claim 1, wherein said herbicidal composition comprising:
a. S-metolachlor is present in an amount of 6% w/w;
b. Metribuzin is present in an amount of 6% w/w;
c. Pyroxasulfone is present in amount of 4.8% w/w;
d. Vegetable oil is present in an amount of 0.5% w/w; and
e. at least one agriculturally acceptable excipient.

7. The herbicidal composition as claimed in claim 1, wherein said herbicidal composition is in a form selected from the group comprising of water-soluble concentrates (SL), emulsifiable concentrates (EC), emulsions (EW), micro-emulsions (ME), Suspension concentrates (SC), oil-based suspension concentrates (OD), flowable suspensions (FS), water-dispersible granules (WDG), wettable granules (WG) water-soluble granules (SG), wettable powders (WP), water soluble powders (SP), granules (GR), encapsulated granules (CG), fine granules (FG), macro granules (GG), dry flowable (DF), aqueous Suspo-emulsions (SE), capsule suspensions (CS) and microgranules (MG).

8. The herbicidal composition as claimed in claim 8, wherein said herbicidal composition is wettable granules (WG).

9. A process for the preparation of an herbicidal composition, comprising:
a. obtaining a homogeneous mixture of S-Metolachlor Technical, Metribuzin Technical and Pyroxasulfone Technical;
b. adding dispersing agent and wetting agent along with buffer and binder to the homogenous mixture of step (a);
c. adding fillers to the mixture of step (b) and mixing uniformly;
d. grinding the mixture obtained in step (c) in a milling process through ACM (Air Classifying Mill) to obtain a particle having size less than 10 microns;
e. adding vegetable oil to the mass obtained in step (d), followed by blending (Post blending mix) to obtain a homogenous mass;
f. preparing a dough by taking the homogenous mass obtained in step (e);
g. preparing and extruding granules through basket extruder; and
h. drying the granules obtained in step (g) in hot air oven to obtain the wettable granules (WG).

10. The process as claimed in claim 10, wherein a) S-metolachlor is present in an amount of 6% w/w; b) Metribuzin is present in an amount of 6% w/w; c) Pyroxasulfone is present in amount of 4.8% w/w; d) Vegetable oil is present in amount of 0.5% w/w.
11. The process as claimed in claim 10, wherein particle size of the formulation is in the range of 0.5-0.8µ.

12. A method for controlling undesired weeds in wheat crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising a) a herbicidally effective amount of S-metolachlor, b) a herbicidally effective amount of Metribuzin c) a herbicidally effective amount of Pyroxasulfone and vegetable oil along with at least one agriculturally acceptable excipient.

13. The method as claimed in claim 13, wherein said herbicidally effective amount of S-metolachlor is in the range of 1-15% w/w, b) said herbicidally effective amount of Metribuzin is in the range of 5-30% w/w c) said herbicidally effective amount of Pyroxasulfone is in the range of 1-15% w/w and d) said vegetable oil is in an amount of 0.1-10% w/w.