Description:FORM 2

THE PATENTS ACT 1970
(SECTION 39 OF 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(Section 10 and Rule 13)

HERBICIDAL COMPOSITION OF PYROXASULFONE AND SULFONYLUREAS

We, COROMANDEL INTERNATIONAL LIMITED,
an Indian company incorporated under Companies Act of 1956,
having its principal place of business at Coromandel House, Sardar Patel Road,
Secunderabad – 500 003, Telangana, India.

The following specification particularly describes the invention and the manner in which it is to be performed:  
FIELD OF THE INVENTION
The present invention relates to a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

Particularly the present invention relates to a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron, Metsulfuron methyl and one or more agrochemical additives.

More particularly, the present invention relates to a process for preparing the synergistic herbicidal composition of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

BACKGROUND OF THE INVENTION
Weeds are undesired plants that tend to grow along with crops or pastures. These plants can grow faster than crops and compete with them for light, nutrients, water, and space thereby diminishing their growth. Weeds eventually increase production costs and farmers end up wasting their resources on unfruitful plant species. Controlling such undesired weeds is an activity that has thus become essential for all farming practices. Methods of controlling weeds include physical disruption of their growth with equipment including mowing, weed pulling or mulching. Chemical weed control however remains the most effective form of control. In chemical weed control herbicides are applied to weeds or soils to control the growth of weeds.

Researchers have invented several synthetic chemicals and agents that are effective in controlling weeds. The activity of herbicides depends upon the climate, types of weeds, application rate etc. Individual herbicides have a limited scope of activity in terms of weed control. More often, farmers use multiple herbicides in various rounds with different application rates to control the vast spectrum of weeds that may be growing along with the crop. The combination of herbicidal active ingredients can offer a more effective solution for weed control than individual herbicides. However, development of combinations of herbicidal active ingredients is a complex and challenging process. It is essential to establish the biological compatibility of the active ingredients, avoid phyto-toxicity of the crop plants, ensure stability of the combination, and avoid herbicide antagonism.

Thus, there is a need to develop new and improved compositions of herbicidal active ingredients that are compatible, non-phytotoxic for crop plants and provide effective weed control.

Active compounds having different mechanisms of action are combined to delay the generation of resistance and reduce the amount of application and prevention and treatment costs. Consequently, research is being conducted to produce herbicides and combinations of herbicides that are safer, that have better performance, that require lower dosages, that are easier to use, and that cost less.

Pyroxasulfone is registered to be applied either in the fall, early preplant, or early postemergence, which allows for flexibility in weed control strategy developed by Kumiai Chemical Industry Co., Ltd. It is an isooxazoline, that delivers higher intrinsic activity and a broader spectrum of control of small-seeded broadleaf weeds and grasses. It is a selective herbicide for controlling annual grasses, annual broadleaf weeds, and sedges. This herbicide can only be applied to surface of the agricultural field, and it kills weeds by inhibiting plant shoot growth. Crop maize, wheat, soyabean.

Pyroxasulfone is chemically known as (3-[5-(difluoromethoxy)-1-methyl-3- (trifluoromethyl)pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole). It’s preparation and use are disclosed in US 7,238,689 and has the following chemical structure:

Sulfosulfuron is a novel sulfonylurea herbicide with an imidazo [1, 2-a] pyridine moiety. It shows excellent herbicidal activity pre-emergent or post-emergent form of control on invasive weeds. It was originally created to protect against stubborn weeds growing around crops. Particularly wheat, triticale. Branched chain amino acid synthesis (ALS or AHAS) inhibitor acts by inhibiting biosynthesis of the essential amino acid’s valine and isoleucine, hence stopping cell division and plant growth. Selectivity derives from rapid metabolism in the crop.

Sulfosulfuron is chemically known as 1-(4,6-dimethoxypyrimidin-2-yl)-3-(2-ethylsulfonylimidazo[1,2-a] pyridin-3-yl)sulfonylurea. It’s preparation and use are disclosed in US 5,017,212 and has the following chemical structure:

Metsulfuron-methyl is an organic compound classified as a sulfonylurea herbicide, which kills broadleaf weeds and some annual grasses. It is a pre-emergence and post-emergence herbicide used to control annual grasses, brush, woody plants, and broadleaf weeds. It can be applied to cereals including barley, rye and wheat and to pastures. It is primarily used to control brush, woody plants and broadleaf weeds on rights-of-way, fence rows, storage areas, highways, and other non-crop areas.

Metsulfuron methyl is chemically known as methyl 2-(N-((4-methoxy-6-methyl-1 ,3,5-triazin-2-yl)carbamoyl)sulfamoyl)benzoate that inhibits the acetolactate synthase (ALS) in plants as described in US 4,394,506 and has the following structure:

The inventors of the present invention have surprisingly found that an herbicidal combination of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl and its formulation has its own benefits such as it has lower application rate that not only reduces the amount of an active substance required for application, but as a rule, also reduces the economic outlay and improve the eco-friendliness of the herbicide treatment. 
OBJECTIVE OF THE INVENTION
One objective of the present invention is to provide a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

Another objective of the present invention is to provide a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron, Metsulfuron methyl and one or more agrochemical additives.

Another objective of the present invention is to provide a synergistic water-dispersible granule (WDG) composition comprising Pyroxasulfone, Sulfosulfuron, Metsulfuron methyl and one or more agrochemical additives.

Another objective of the present invention is to provide a process for preparing the synergistic herbicidal composition of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

SUMMARY OF THE INVENTION
Accordingly, the present invention provides a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

In one aspect, the present invention provides a synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron, Metsulfuron methyl and one or more agrochemical additives.

In another aspect, the present invention provides a synergistic composition comprising of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl with an improved stability and ready to use herbicidal composition, having superior bio-efficacy compared to the individual formulations.

In another aspect, the present invention provides a water dispersible granule composition comprising:
a) Pyroxasulfone,
b) Sulfosulfuron,
c) Metsulfuron methyl and
d) other agrochemical additives.

In another aspect, the present invention provides a water-dispersible granule composition comprising:
a) Pyroxasulfone in a range of 25% to 55% (w/w),
b) Sulfosulfuron in a range of 5% to 20% (w/w),
c) Metsulfuron methyl in a range of 0.1% to 5%(w/w),
d) wetting agent in a range of 1% to 10% (w/w),
e) dispersing agent in a range of 1% to 10% (w/w),
f) other agrochemical additives in a range of 20% to 80% (w/w).

In another aspect, the present invention provides a synergistic water-dispersible granule composition comprising of Pyroxasulfone, Sulfosulfuron Metsulfuron methyl, wetting agent, dispersing agent and one or more agrochemical additives, wherein agrochemical additives are selected from disintegrating agent, defoamer and filler.

In another aspect, the present invention provides a water-dispersible granule composition comprising:
a) Pyroxasulfone in a range of 25% to 55% (w/w),
b) Sulfosulfuron in a range of 5% to 20% (w/w),
c) Metsulfuron methyl in a range of 0.1% to 5%(w/w),
d) wetting agent in a range of 1% to 10% (w/w),
e) dispersing agent in a range of 1% to 10% (w/w),
f) disintegrating agent in a range of 5% to 15% (w/w),
g) defoamer in a range of 0.1 % to 5% (w/w) and
h) filler in a range of 10% to 60% (w/w).

In another aspect, the present invention provides a process for the preparation of synergistic composition comprising of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl.

In yet another aspect, the present invention provides a process for preparing a synergistic water dispersible granule composition comprising steps of:
a) weighing and pre-blending all the active ingredients, wetting agent, dispersing agent, and other agrochemical additives in a pre-blender, and mixing for 1 hr.
b) milling the mixture through air jet mill instrument with an inlet pressure 2-3 kg/cm2 and grinding pressure of 6-6.5 kg/cm2 to obtain particles of size D90 < 10 micron.
c) collecting the milled material and post blending the sample for 1 hr.
d) preparing the dough with 12% water or solvent and extrusion of the granules through (0.8 – 1.0 mm mesh)
e) collecting the granules and drying in fluidized bed dryer at 45C for 20 min.
f) packing the formulated material in a suitable packaging.

In yet another aspect, the present invention provides a process for preparing a synergistic water dispersible granule composition comprising steps of:
a) weighing and pre-blending all the active ingredients, wetting agent, dispersing agent, and other agrochemical additives in a pre-blender, and mixing for 1 hr.
b) milling the mixture through air jet mill instrument with an inlet pressure 2-3 kg/cm2 and grinding pressure of 6-6.5 kg/cm2 to obtain particles of size D90 < 10 micron.
c) collecting the milled material and post blending the sample for 1 hr.
d) preparing the dough with 12% water or solvent and extrusion of the granules through (0.8 – 1.0 mm mesh)
e) collecting the granules and drying in fluidized bed dryer at 45C for 20 min.
f) sending the sample for quality analysis.
g) packing the formulated material in a suitable packaging.

In yet another aspect of the present invention is to provide an herbicidal composition with synergistic herbicidal effect against undesirable plants and vegetation.

In yet another aspect of the present invention provides an herbicidal composition of pyroxasulfone, sulfosulfuron and metsulfuron methyl and its formulation has an improved stability and ready to use, having superior bio-efficacy compared to the individual formulations.

DESCRIPTION OF THE INVENTION
The term "comprising", which is synonymous with "including", "containing", or "characterized by” here is defined as being inclusive or open-ended, and does not exclude additional, unrecited elements or method steps, unless the context clearly requires otherwise.

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.

As used herein, the terms "crops" and "vegetation" can include, for instance, dormant seeds, germinant seeds, emerging seedlings, plants emerging from vegetative propagules, immature vegetation, and established vegetation.

As used herein, immature vegetation may be understood to include small vegetative plants prior to reproductive stage, and mature vegetation may be understood to include vegetative plants during and after the reproductive stage.

As used herein, the terms “herbicide” may be understood as a substance that is toxic to plants, used to destroy unwanted vegetation.

As used herein, the term “synergistic composition” may be understood to include effective combination of more than one agrochemical that allows the application of the said agrochemical in a much lower dosage, which results in a less dosage treatment for the crops.

As used herein, the term “water dispersible granule” formulation may be understood as 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.

As used herein, the term “agrochemical additives” may be understood to include a range of surfactants, dispersing agents, pigments, solvents, co-solvents, defoamers, and emulsions, crystallization inhibitors, viscosity modifiers, suspending agents, dyes, antioxidants, , light absorbers, mixing aids, neutralizers or pH adjusting substances and buffers, corrosion inhibitors, fragrances, wetting agents, absorption enhancers, micronutrients, plasticizers, lubricants, thickeners, anti-freezing agents, sterilization agents, biocide, adjuvant among others.

The herbicidal composition of the present invention may be 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) Tablet (TB), Water dispersible granules (WG or WDG), Wettable powder (WP), Water dispersible powder for slurry seed treatment (WS), Water dispersible tablet (WT), a mixed formulation of CS and SC (ZC), a mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW) among others.

In one embodiment, the present invention is to provide a water-dispersible granule composition comprising of:
a) Pyroxasulfone,
b) Sulfosulfuron,
c) Metsulfuron methyl and
d) other agrochemical additives.

In another embodiment of the present invention, Pyroxasulfone is present in a range of 25% (w/w) to 55% (w/w); Sulfosulfuron is present in a range of 5% (w/w) to 20% (w/w), and Metsulfuron methyl in a range of 0.1% to 5%(w/w),

In another embodiment of the present invention the agrochemical additives selected from wetting agent, dispersing agent, disintegrating agent, defoamer and filler.

The wetting agent is a compound that facilitates rapid wetting of the powder when added to the water. The wetting agent employed in the formulation composition is selected from the group consisting of non-ionic surfactants, anionic surfactant and a mixture of anionic and non-ionic surfactant and polymeric surfactant.

The wetting agent is selected from and not limited to polycondensation product of naphthalene sulfonic acid, which is alkyl naphthalene sulphonate sodium salt, dialkyl naphthalene sulphonate sodium salt (Supragil WP), alkylnaphthalene sulfonate (ANS) condensate blend (Morwet EFW), sodium alkyl naphthalene sulfonate (Morwet 3028), polyalkyl naphthalene sulphonate, Aqarius BP14332 Yellow IH, salts of alkylphenol condensates, salts of sulphonated lignins, salts of poly acid resin copolymers, salts of polyphenol formaldehyde resins, salts of polyarylether sulphates such as tristyrylphenolethoxylate sulphate salts, alkoxylated alkylphenols and alcohols as well as block copolymers of ethyleneoxide, sodium lauryl sulphate and alcohol derivatives, tristyrylphenol ethoxylate (Sophrophor BSU), polyethyleneglycol nonylphenyl ether ammonium sulfate (Dispersol PS), propylene oxide, sodium salt of poly carboxylic acid (Jeemol D777).

The wetting agent is present in the composition in a range of 1% to 10% (w/w), more preferably 2% to 6% (w/w) of the total weight of the composition

As used herein, the term “dispersing agent ” may be understood as a chemical substance, which is typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their settling or clumping. They can disperse active ingredients in the formulation and prevent agglomeration after dispersal in water.

The dispersing agent is selected from and not limited to sodium lignosulphonates, sodium lauryl sulphate, sodium 14 naphthalene sulphonate formaldehyde condensates, sodium polyalkylnaphthalene sulphonate (Dispersol BB4), sodium polycarboxylate (Geropon T 36), sodium methyl oleoyl taurate (Geropon T 77), phenol sulfonic acid-formaldehyde polycondensation as sodium salt (Tamol FBPP), sodium salt of methyl naphthalene sulfonate (Supragil MNS 90), phenol sulfonic acid formaldehyde polycondensation sodium (Dispersol PSR19), calcium dodecylbenzene sulfonate (Rhodocal 60 BR), polyalkoxylated butyl ether (Ethylan NS 500 LQ), phenol sulfonic acid formaldehyde (Tamol DN), tristyrylphenol ethoxylate phosphate esters, aliphatic alcohol ethoxylates, alky ethoxylates; EO-PO block copolymers, and graft copolymers, acrylate copolymer (Agrilan 789), polycarboxylates, alkyl naphthalene sulfonates (such as Morwet IP, Morwet EFW), sodium salt of naphthalene sulfonate condensate (Morwet D-425), phenol sulphonic acid condensates, alkyl sulfonates, alkenyl sulfonates, mixture of alkyl sulfonates and alkenyl sulfonates (Lissapol D), alkyl suflosuccinates (Geropon), L-Wet, methyl oleyltaurates , poly vinyl alcohols and sodium salt of alkylated naphthalene sulphonate formaldehyde (Jeemol DW18) or a combination thereof among others.

The dispersing agent is present in the composition in a range of 1% to 10% (w/w), more preferably 2% to 6% (w/w) of the total weight of the composition.

As used herein, the term “disintegrating agent” may be understood as an additive that can be useful for improving dispersibility of the herbicidal formulation.

The disintegrating agent used in the present invention is selected from and not limited to ammonium sulphate, sodium tripolyphosphate, sodium salt of naphthalene sulfonate, sodium polycarboxylate and disodium hydrogen orthophosphate among others.

The disintegrating agent is present in the composition in a range of 5% to 15% (w/w), more preferably 8% to 12% (w/w) of the total weight of the composition.

As used herein, the term “defoamer” may be understood as a chemical additive which is used to reduce and hinder the formation of foam in the formulations.

The defoamer used in the present invention is selected from and not limited to insoluble oils, polydimethylsiloxanes(e.g. SAG-1572), polydimethylsiloxane (Dowsil GP 4314), Dowsil GP 4312, Rhodorsil ep 6703 and other silicones, certain alcohols, stearates , glycols among others.

The defoamer is present in the composition in a range of 0.1% to 5% (w/w), more preferably 0.5% to 2% (w/w) of the total weight of the composition.

As used herein, the term “filler” may be understood as excipients used to increase the volume of the material to enable easier processing of the ingredients and make it into a size suitable for use. Moreover, they can stabilize the final product and help during manufacturing.

The filler used in the present invention is selected from and not limited to China clay, kaolin, starch, lactose monohydrate, potassium carbonate and calcium carbonate,

The filler is present in the composition in a range of 10% to 60% (w/w), more preferably 15% to 45% of the total weight of the composition.

The solvent used in the present invention is selected from and not limited to water, isopropyl alcohol, and methanol.

In yet another embodiment of the present invention is to provide a process for preparing a water dispersible granule composition comprising steps of:
a) weighing and pre-blending all the active ingredients, wetting agent, dispersing agent, disintegrating agent and other agrochemical additives in a pre-blender, and mixing for 1 hr.
b) milling the mixture through air jet mill instrument with an inlet pressure 2-3 kg/cm2 and grinding pressure of 6-6.5 kg/cm2 to obtain particles of size D90 < 10 micron.
c) collecting the milled material and post blending the sample for 1 hr.
d) preparing the dough with 12% water or solvent and extrusion of the granules through (0.8 – 1.0 mm mesh)
e) collecting the granules and drying in fluidized bed dryer at 45C for 20 min.
f) sending the sample for quality analysis.
g) packing the formulated material in suitable packaging.

Preparation of composition of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl in water dispersible granule form (WDG) comprising below steps:
Step 1: Weighing the raw materials according to the batch size as follows:
a) pyroxasulfone,
b) sulfosulfuron,
c) metsulfuron methyl,
d) dispersing agent,
e) wetting agent,
f) disintegrating agent,
g) defoamer,
h) filler and
all this raw material in a pre-blender and mixing it for 1 hr.
Step 2: Milling the sample through air jet mill instrument. Inlet pressure 2-3 kg/cm2, grinding pressure 6 – 6.5 kg/ cm2 , and check the particle size D90 < 10 micron.
Step 3: Collecting the milled material, and post blending the sample for 1hr.
Step 4: Preparing dough and 12% water or solvent extrusion of the granule (0.8 – 1.0 mm mesh).
Step 5: Collecting the granules and drying in the fluidized bed dryer at 45-degree for 20 min. Submitting the sample for analysis by maintaining the moisture 3%.
Step.6: Sending the sample to the Quality analysis.
Step 7: Packing the formulated material in suitable packaging.

The composition of the present invention and method provided may be utilized to control weeds or battle undesired vegetation in crops or other settings, including but not limited to cereals, such Maize, soyabeans, wheat, triticale, and industrial vegetation management. Preferably, the undesirable vegetation includes species from the families of broadleaved and grass weeds, more preferably from the families of Aeschynomene, Ageratum, Amaranthus, Bidens, Brachiaria, Cenchrus, Cyperus, Digitaria, Echinochloa, Eclipta, Eleusine, Eragrostis Fimbristylis, Galinsoga, Ischaemum, Leptochloa, Monochoria, Panicum, Paspalum, Polygonum, Portulaca, Richardia, Sesbania, Setaria, Sida, Sorghum, most preferably Echinochloa, Leptochloa, Ischaemum, Monochoria, and Cyperus, or combinations thereof. It has been surprisingly found that the novel herbicidal composition of the present invention delays the appearance of the resistant strains of weeds and achieves effective and economical control of undesired weeds.

The composition achieves improved biological activity by enhancing overall control of weeds over a shorter period. Additional benefits of using the herbicidal composition of the present invention includes reduced risk of occupational hazard, lower cost of application, better cost: benefit ratio to the end user, reduced fuel, and labor cost, saving in applicator’s time and loss caused by mechanical damage to the crop and soil.

The present compositions can be applied to the undesirable vegetation and/or weeds or their locus using conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation or paddy water, and by other conventional means known to those skilled in the art.

The combinations of the present invention have several advantages over solo application of either pyroxasulfone or sulfosulfuron or metsulfuron methyl, and, likewise, over any binary combination of these herbicides. The combination of the present invention shows enhanced herbicide action in comparison with the herbicide action of solo action of pyroxasulfone, sulfosulfuron and metsulfuron methyl against undesirable vegetation. Moreover, the combinations of the invention show a persistent herbicidal activity, even under difficult weathering conditions, and minimize the risk of weeds escaping. The combinations are generally non-toxic or of low toxicity against mammals. Apart from that, the combinations of the present invention show superior crop compatibility with certain conventional crop plants and with herbicide tolerant crop plants, i.e., their use in these crops leads to a reduced damage of the crop plants and/or does not result in increased damage of the crop plants. Thus, the combinations of the invention can also be applied after the emergence of the crop plants. The combinations of the present invention may also show an accelerated action on harmful plants, i.e., they may effect damage of the harmful plants more quickly in comparison with solo or binary applications of the at least three herbicides involved.

From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the 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.

The following examples describes the nature of the invention which are given only for the purpose of illustrating the present invention in more detail and are not limitative and relate to solutions

Examples:

Example 1
Table 1: Pyroxasulfone 40% + Sulfosulfuron 12% + Metsulfuron methyl 1.67% (WDG)
S. No Composition Function % (w/w)
1. Pyroxasulfone Active Ingredient 40.0
2. Sulfosulfuron Active Ingredient 12.0
3. Metsulfuron methyl Active Ingredient 1.67
4. Dialkyl naphthalene sulphonate sodium salt Wetting agent 2.0
5. Sodium salt of methyl naphthalene sulfonate Dispersing agent 4.0
6. Polydimethylsiloxane Defoamer 0.5
7. Ammonium sulphate Disintegrating agent 10.0
8. China clay Filler 29.83
Total 100

Manufacturing process
40.0 gm of Pyroxasulfone, 12.0 gm of Sulfosulfuron, 1.67 gm of Metsulfuron methyl, 2.0 gm of dialkyl naphthalene sulphonate sodium salt, 4.0 gm of sodium salt of methyl naphthalene sulfonate, 0.5 gm of polydimethylsiloxane, 10 gm of ammonium sulphate and 29.83 gm of China clay were weighed in the pre-blender reactor and mixed for 1 hour. The mixture was milled through air jet mill instrument (Inlet pressure 2-3 kg/cm2, grinding pressure 6-6.5kg/ cm2) to obtain the desired particle size (D90 < 10 microns). Collecting the milled material and post blending the material for 1 hour followed by preparing dough (water or solvent). Extruding the granules (0.8-1.0 mm mesh), collecting the granules, and drying at 45 o C for 20 min followed by packing the material in a suitable package.

Example 2
Table 2: Pyroxasulfone 30% + Sulfosulfuron 5% + Metsulfuron methyl 0.5% (WDG)
S. No Composition Function % (w/w)
1. Pyroxasulfone Active Ingredient 30.0
2. Sulfosulfuron Active Ingredient 5.0
3. Metsulfuron methyl Active Ingredient 0.5
4. Alkylnaphthalene sulfonate (ANS) condensate Wetting agent 3.0
5. Acrylate copolymer Dispersing agent 5.0
6. Polydimethylsiloxane Defoamer 1.0
7. Starch Filler 55.5
Total 100

Manufacturing process
30.0 gm of Pyroxasulfone, 5.0 gm of Sulfosulfuron, 0.5 gm of Metsulfuron methyl, 3.0 gm of alkylnaphthalene sulfonate (ANS) condensate, 5.0 gm of acrylate copolymer, 1.0 gm of polydimethylsiloxane and 55.5 gm of starch were weighed in the pre-blender reactor and mixed for 1 hour. The mixture was milled through air jet mill instrument (Inlet pressure 2-3 kg/cm2, grinding pressure 6-6.5kg/ cm2) to obtain the desired particle size (D90 < 10 microns). Collecting the milled material and post blending the material for 1 hour followed by preparing dough (water or solvent). Extruding the granules (0.8-1.0 mm mesh), collecting the granules, and drying at 45 o C for 20 min followed by packing the material in a suitable package.

Example 3
Table 3: Pyroxasulfone 35% + Sulfosulfuron 8% + Metsulfuron methyl 0.9% (WDG)
S. No Composition Function % (w/w)
1. Pyroxasulfone Active Ingredient 35.0
2. Sulfosulfuron Active Ingredient 8.0
3. Metsulfuron methyl Active Ingredient 0.9
4. Sodium salt of polycarboxylic acid Wetting agent 6.0
5. Phenol sulfonic acid formaldehyde sodium Dispersing agent 6.5
6. Sodium tripolyphosphate Disintegrating agent 10.0
7. Polydimethylsiloxane Defoamer 1.0
8. Calcium carbonate Filler 32.6
Total 100

Manufacturing process
35.0 gm of Pyroxasulfone, 8.0 gm of Sulfosulfuron, 0.9 gm of Metsulfuron methyl, 6.0 gm of sodium salt of polycarboxylic acid, 6.5 gm of phenol sulfonic acid formaldehyde sodium, 10.0 gm of sodium tripolyphosphate, 1.0 gm of polydimethylsiloxane and 32.6 gm of calcium carbonate were weighed in the pre-blender reactor and mixed for 1 hour. The mixture was milled through air jet mill instrument (Inlet pressure 2-3 kg/cm2, grinding pressure 6-6.5kg/ cm2) to obtain the desired particle size (D90 < 10 microns). Collecting the milled material and post blending the material for 1 hour followed by preparing dough (water or solvent). Extruding the granules (0.8-1.0 mm mesh), collecting the granules, and drying at 45 o C for 20 min followed by packing the material in a suitable package.

Example 4
Table 4: Pyroxasulfone 45% + Sulfosulfuron 10% + Metsulfuron methyl 1.5% (WDG)
S. No Composition Function % (w/w)
1. Pyroxasulfone Active Ingredient 45.0
2. Sulfosulfuron Active Ingredient 10.0
3. Metsulfuron methyl Active Ingredient 1.5
4. Sodium lauryl sulphate and alcohol derivatives Wetting agent 3.0
5. Sodium polycarboxylate Dispersing agent 9.0
6. Polydimethylsiloxane Defoamer 1.0
7. Lactose monohydrate Filler 30.5
Total 100

Manufacturing process
45.0 gm of Pyroxasulfone, 10.0 gm of Sulfosulfuron, 1.5 gm of Metsulfuron methyl, 3.0 gm of sodium lauryl sulphate and alcohol derivatives, 9.0 gm of sodium polycarboxylate, 1.0 gm of polydimethylsiloxane and 30.5 gm of lactose monohydrate were weighed in the pre-blender reactor and mixed for 1 hour. The mixture was milled through air jet mill instrument (Inlet pressure 2-3 kg/cm2, grinding pressure 6-6.5kg/ cm2) to obtain the desired particle size (D90 < 10 microns). Collecting the milled material and post blending the material for 1 hour followed by preparing dough (water or solvent). Extruding the granules (0.8-1.0 mm mesh), collecting the granules, and drying at 45 o C for 20 min followed by packing the material in a suitable package.

Example 5
Table 5: Pyroxasulfone 50% + Sulfosulfuron 15% + Metsulfuron methyl 2.0% (WDG)
S. No Composition Function % (w/w)
1. Pyroxasulfone Active Ingredient 50.0
2. Sulfosulfuron Active Ingredient 15.0
3. Metsulfuron methyl Active Ingredient 2.0
4. Polyethyleneglycol nonylphenyl ether ammonium sulfate Wetting agent 5.0
5. Sodium polycarboxylate Dispersing agent 9.0
6. Potassium carbonate Filler 18.0
7. Polydimethylsiloxane Defoamer 1.0
Total 100

Manufacturing process
The process for manufacture of composition of Table 5 is as follows: 50.0 gm of Pyroxasulfone, 15.0 gm of Sulfosulfuron, 2.0 gm of Metsulfuron methyl, 5.0 gm of polyethylene glycol nonylphenyl ether ammonium sulfate, 9.0 gm of sodium polycarboxylate, 18.0 gm of potassium carbonate and 1.0 gm of polydimethylsiloxane were weighed in the pre-blender reactor and mixed for 1 hour. The mixture was milled through air jet mill instrument (Inlet pressure 2-3 kg/cm2, grinding pressure 6-6.5kg/ cm2) to obtain the desired particle size (D90 < 10 microns). Collecting the milled material and post blending the material for 1 hour followed by preparing dough (water or solvent). Extruding the granules (0.8-1.0 mm mesh), collecting the granules, and drying at 45 o C for 20 min followed by packing the material in a suitable package.

FIELD EFFICACY AND SYNERGY STUDIES

The field studies were conducted to compare the weed controlling activity of the combination of Pyroxasulfone, Sulfosulfuron and Metsulfuron methyl. The active ingredient Pyroxasulfone in the combination, belongs to chemical family “Isooxazolines” with mode of action of inhibition of very long chain fatty acids synthesis (VLCFA) inhibitors and Sulfosulfuron & Metsulfuron methyl are belonging to chemical family “Sulfonylureas” with ALS inhibitor (inhibition of acetolactate synthase) mode of action. Combination has the potential of controlling the cross-spectrum weeds (broad leaf weeds & grassy weeds) in wheat at the pre-emergence to extended pre-emergence (0-10 DAS) application timing. Both the molecules are safe to wheat when applied at their recommended dose rate in pre-emergence to extended pre-emergence (0-10 DAS) application timing.

The weed control activity of the individual herbicides of the invention and their combinations were evaluated on weeds such as Phalaris minor, Melilotus alba, Rumex dentatus & Chenopodium album. Trials were conducted with randomized block design with net plot size of 5 m x 6 m. Each trial was replicated four times and conducted under GEP guidelines. Spraying was done with manual operated backpack knapsack sprayer with 300 L of water spray volume per hectare at pre-emergence to extended pre-emergence (0-10 DAS) application timing. Such field trials were carried out at various locations to generate independent data, the locations were chosen randomly across India. Visual observations were recorded on percent weed control for individual weeds on whole plot basis at 15 days after application. These observations are to be taken from entire plot.

Appropriate analysis of plant response to herbicide combination is critical in determining the type of activity observed. The most widely used model is one Gowing* derived and Colby** modified. Gowing described a mathematical formula for calculating the predicting response values for herbicide mixtures. He suggested the expected (E) percent inhibition of growth induced by herbicide A plus herbicide B is as follows, *(Jerry Flint et al, 1988) ***
If A1 = the percent inhibition of growth by herbicide A at given rate
B1 = the percent inhibition of growth by herbicide B at given rate then,
B1 (100 – A1)
E = A1 +
100
When the percentage of pesticidal control observed for the combination is greater than the expected percentage, there is a synergistic effect. (Ratio of O/E > 1, means synergism observed.)

Reference:
*Gowing, D. P. 1960. Comments on tests of herbicide mixtures. Weeds 8:379–391.
**Colby, S. R. 1967. Calculating synergistic and antagonistic responses of herbicide combinations. Weeds 15:20–22
*** Jerry Flint et al, 1988. Analyzing Herbicide Interactions: A Statistical Treatment of Colby's Method. Weed Technology 2: 304-309

The herbicide combinations, application rates, plant species tested, and results are given in the following tables:

Table 6: Table 6 demonstrates synergy on weeds using the combination of Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 15 days of application. The target weed was Phalaris minor, and the results are recorded in the below table.

Active
Dose (GAH) Pre-emergence (0 – 3 DAS) Extended pre-emergence (8 – 10 DAS)
% Weed Control of Phalaris minor % Weed Control of Phalaris minor
Pyroxasulfone 120 75 60
Sulfosulfuron 36 30 70
Metsulfuron methyl 5 0 10
Pyroxasulfone 40% + Sulfosulfuron 12% + Metsulfuron methyl 1.67% WDG 120 + 36 + 5 92 95
WDG – Water dispersible granules; GAH – Gram active per hectare

The Phalaris minor control results in table 6 clearly demonstrates, synergy between Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 7: Table 7 demonstrates synergy on weeds using the combination of Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 15 days of application. The target weed was Chenopodium album, and the results are recorded in the below table.

Active
Dose (GAH) Pre-emergence (0 – 3 DAS) Extended pre-emergence (8 – 10 DAS)
% Weed Control of Chenopodium album % Weed Control of Chenopodium album
Pyroxasulfone 120 60 50
Sulfosulfuron 36 60 60
Metsulfuron methyl 5 40 50
Pyroxasulfone 40% + Sulfosulfuron 12% + Metsulfuron methyl 1.67% WDG 120 + 36 + 5 95 95
WDG – Water dispersible granules; GAH – Gram active per hectare

The Chenopodium album control results in table 7 clearly demonstrates, synergy between Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 8: Table 8 demonstrates synergy on weeds using the combination of Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 15 days of application. The target weed was Melilotus alba, and the results are recorded in the below table.

Active
Dose (GAH) Pre-emergence (0 – 3 DAS) Extended pre-emergence (8 – 10 DAS)
% Weed Control of Melilotus alba % Weed Control of Melilotus alba
Pyroxasulfone 120 40 35
Sulfosulfuron 36 50 60
Metsulfuron methyl 5 45 50
Pyroxasulfone 40% + Sulfosulfuron 12% + Metsulfuron methyl 1.67% WDG 120 + 36 + 5 88 90
WDG – Water dispersible granules; GAH – Gram active per hectare

The Melilotus alba control results in table 8 clearly demonstrates, synergy between Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre-emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 9: Table 9 demonstrates synergy on weeds using the combination of Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 15 days of application. The target weed was Rumex dentatus, and the results are recorded in the below table.

Active
Dose (GAH) Pre-emergence (0 – 3 DAS) Extended pre-emergence (8 – 10 DAS)
% Weed Control of Rumex dentatus % Weed Control of Rumex dentatus
Pyroxasulfone 120 30 30
Sulfosulfuron 36 60 55
Metsulfuron methyl 5 50 50
Pyroxasulfone 40% + Sulfosulfuron 12% WDG + Metsulfuron methyl 1.67% WDG 120 + 36 + 5 88 87
WDG – Water dispersible granules; GAH – Gram active per hectare

The Rumex dentatus control results in table 9 clearly demonstrates, synergy between Pyroxasulfone, Sulfosulfuron & Metsulfuron methyl in pre-emergence and extended pre emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

The composition of the present invention have the below advantages

 The present invention provides a synergistic herbicidal composition with broad spectrum activity and can delay the onset of herbicidal resistance.
 The present invention provides an herbicidal composition that can be applied in a single shot reducing the burden on farmers.
 The present invention provides an herbicidal composition which increases shoot and tiller counts which directly contribute to the crop yield.
 The present invention provides an herbicidal composition that shows effective treatment and prevention of growth or germination of weeds.
 The present invention provides an herbicidal composition that is non phyto-toxic to crop plants. , Claims:WE CLAIM:

1. A synergistic herbicidal composition comprising Pyroxasulfone, Sulfosulfuron, Metsulfuron methyl and one or more agrochemical additives.

2. The composition as claimed in claim 1, wherein the composition is formulated as water dispersible granules (WDG).

3. The composition as claimed in claim 1, wherein the Pyroxasulfone is present in the range of 25% to 55% (w/w), Sulfosulfuron is present in the range of 5% to 20% (w/w) and Metsulfuron methyl is present in a range of 0.1% to 5% (w/w).

4. The composition as claimed in claim 1, wherein the other agrochemical additives are selected from wetting agent, dispersing agent, disintegrating agent, defoamer and a filler.

5. The composition as claimed in claim 4, wherein the wetting agent is selected from a group comprising alkylnaphthalene sulfonate (ANS) condensate, dialkyl naphthalene sulphonate sodium salt, sodium salt of polycarboxylic acid, sodium lauryl sulphate and alcohol derivatives, polyethylene glycol nonylphenyl ether ammonium sulfate, present in a range of 1% to 10% (w/w) of the total weight of the composition.

6. The composition as claimed in claim 4, wherein the dispersing agent is selected from a group comprising sodium salt of methyl naphthalene sulfonate, acrylate copolymer, phenol sulfonic acid formaldehyde sodium, sodium polycarboxylate, sodium ligno sulphonate, sodium salt of alkylated naphthalene sulphonate formaldehyde or a combination thereof, present in a range of 1% to 10% (w/w) of the total weight of the composition.

7. The composition as claimed in claim 4, wherein the disintegrating agent is selected from ammonium sulphate and sodium tripolyphosphate, present in a range of 5% to 15% (w/w).

8. The composition as claimed in claim 4, wherein the defoamer is polydimethylsiloxane present in a range of 0.1 % to 5% (w/w).

9. The composition as claimed in claim 4, wherein the filler is selected from a group comprising China clay, starch, calcium carbonate, lactose monohydrate and potassium carbonate present in a range from 10% to 60% (w/w).

10. The process for the preparation of composition as claimed in claims 1-9, wherein said process comprising steps of:
a) weighing all the active ingredients, wetting agent, dispersing agent, disintegrating agent and other agrochemical additives in a pre-blender, and mixing for 1 hour.
b) milling the mixture through air jet miller instrument (Inlet pressure 2-3 kg/cm2 and grinding pressure 6 kg/cm2) to obtain particles of size D90 < 10µ,
c) collecting the milled material and post blending for 1 hour,
d) preparing the dough with 12% water or solvent and extrusion of the granules through (0.8 to 1.0mm mesh),
e) collecting the granules and drying in fluidized bed dryer (FBD) at 45 oC air flow for 20 min by maintain the moisture content 2%,
f) packing the formulated material in a suitable packaging.

Dated this Eleventh (11th) day of November, 2022

_______________________________
Dr. S. Padmaja
Agent for the Applicant
IN/PA/883