DESC:FORM 2

THE PATENTS ACT 1970
(SECTION 39 OF 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(Section 10 and Rule 13)

SYNERGISTIC HERBICIDAL COMPOSITION OF PINOXADEN AND METRIBUZIN

We, COROMANDEL INTERNATIONAL LIMITED,
an Indian company incorporated under the Companies Act, 1956, and validly existing under the Companies Act, 2013. Having its registered office 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 of phenyl pyrazoline and metribuzin. Particularly the present invention relates to a synergistic herbicidal composition comprising of pinoxaden and metribuzin with one or more agrochemical additives in synergistically effective amounts.

The present invention also relates to a method of controlling or preventing unwanted vegetation in a crop planting site and reducing the amount of post-emergent herbicide necessary for controlling or preventing unwanted vegetation.

BACKGROUND OF THE INVENTION
Over time, the control of unwanted vegetation in crop planting sites according to traditional treatment schemes has been strained. In some cases, various weed species have developed resistance to certain post-emergent herbicides, as well as other post-emergent herbicides. As a result, application rates and quantities have been increased to gain control over unwanted vegetation. However, this approach merely exacerbates the resistance problem and increases the cost of crop production at a given site. Thus, attempting to maintain weed control by merely increasing the post-emergent application dose of a given herbicide is not a viable approach for long term management and control of unwanted vegetation in crop planting sites.

Additionally, the increasing use of high application rates of post-emergent herbicides may prove to be detrimental to crop growth. Likewise, the increased application of herbicides may negatively impact the local environment. Accordingly, it is increasingly necessary to balance weed control with environmental needs. This is a difficult task, though, since environmental considerations tend to necessitate the use of reduced quantities of herbicidally active substances to control unwanted vegetation.

Accordingly, there remains a need for a more effective method of controlling or preventing the growth of unwanted vegetation in planting sites by using reduced quantities of herbicidally active substances.

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.

Pinoxaden is a representative of the new phenyl pyrazoline class of chemicals, which is a highly selective systemic herbicide used to control monocotyledonous grass weeds in crops such as wild oats, rye grass and black grass in winter and spring wheat and spring barley. Pinoxaden is developed by Syngenta and is used against grasses. The effect is based on influencing the lipid metabolism of the cells. It inhibits acetyl-CoA carboxylase.

Pinoxaden is approved for post emergence control of grass weeds in wheat (including durum) and barley. The product has to be applied as one application per crop season by agricultural workers using either open-cab ground boom equipment or via aerial application.

Pinoxaden is chemically known as 8-(2,6-Diethyl-p-tolyl)-1,2,4,5-tetrahydro-7-oxo-7H-pyrazolo[1,2-d][1,4,5]oxadiazepine-9-yl-2,2-dimethylpropionate and has the following chemical structure:

Metribuzin is a synthetic organic compound and widely used herbicide applied in preemergence and postemergence on intensive vegetable crops. It is known for its efficiency and relatively low toxicity. Metribuzin is slightly soluble in water, and slightly soluble in several organic solvents. Because it is available for runoff, contamination of soil, groundwater, and surface waters has been reported. Metribuzin and its degradates are very mobile and highly persistent, and thus have the potential to contaminate ground water and surface water; however, the persistence of parent metribuzin in surface water may be lessened by its susceptibility to photolytic degradation.

Metribuzin is an herbicide used both pre- and post-emergence in crops including soyabean, potatoes, tomatoes, and sugar cane.

Metribuzin is chemically known as 4-amino-6-tert-butyl-3-(methylthio)-1,2,4-triazin-5(4H)-one and has the following chemical structure:

WO 2012/123408 A1 of Bayer Crop science Ag, discloses a liquid herbicidal emulsifiable concentrate (EC) comprising (a) the herbicidal active substance metribuzin, (b) one or more herbicidal active substances selected from the group consisting of the ACCase inhibitors (b1), (b2) and (b3): (b1) esters of fenoxaprop-P and esters of fenoxaprop, (b2) esters of clodinafop, (b3) pinoxaden, (c) optionally other active ingredients, which do not substantially interfere with the stability of the co-formulation, (d) one or more non-polar organic solvent, (e) one or more polar organic co-solvent, (f) one or more non-ionic emulsifiers, (g) one or more anionic emulsifiers, and (h) optionally further formulation auxiliaries.

The inventors of the present invention have developed a solid formulation i.e., a combination of two active components pinoxaden and metribuzin in wettable powder form 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 amount of formulation auxiliaries required. Both reduce the economic outlay and improve the eco-friendliness of the herbicide treatment.

OBJECT OF THE INVENTION
One object of the present invention is to provide a synergistic herbicidal composition comprising pinoxaden and metribuzin.

Another object of the present invention is to provide a synergistic herbicidal composition comprising of pinoxaden and metribuzin with one or more agrochemical additives in synergistically effective amounts.

Yet another object of the present invention is to provide a wettable powder composition comprising of pinoxaden and metribuzin with one or more agrochemical additives and the process thereof.

Yet another object of the present invention is to provide a method of controlling or preventing unwanted vegetation in a crop planting site and reducing the amount of post-emergent herbicide necessary for controlling or preventing unwanted vegetation.

SUMMARY OF THE INVENTION
The present invention provides a synergistic herbicidal composition of pinoxaden and metribuzin comprising of:
a) pinoxaden in a range from 1% (w/w) to 10% (w/w),
b) metribuzin in a range from 20% (w/w) to 30% (w/w), and
c) agrochemical additives.

In one aspect of the present invention provides a wettable powder (WP) formulation of pinoxaden is present in a range from 1% (w/w) to 10% (w/w); and metribuzin is present in a range from 20% (w/w) to 30% (w/w) with one or more agrochemical additives.

In an aspect of the present invention, the agrochemical additives are selected from a wetting agent, a dispersing agent, a defoamer, an anti-caking agent, a filler and co-filler.

In an aspect of the present invention, the wetting agent is selected from the group comprising an anionic sodium diisopropyl naphthalene sulfonate, dialkyl naphthalene sulphonate sodium salt, Propol 990N, Sodium salt of dibutyl naphthalene sulphonate, and Sodium methyl cocoyl taurate, present in a range from 1% to 10% (w/w).

In an aspect of the present invention, the dispersing agent is selected from the group comprising alkyl naphthalene sulfonate, alkyl naphthalene sulfonate condensate, sodium lignosulfonate, and sodium polycarboxylate, present in a range from 5% to 15% (w/w).

In an aspect of the present invention, the defoamer is polydimethylsiloxane, present in a range from 0.1% to 1.5% (w/w).

In an aspect of the present invention, the co-filler is selected from lactose monohydrate, ammonium sulphate and combination thereof, present in a range from 1% to 10% (w/w).

In an aspect of the present invention, the Anti caking agent is silicon dioxide, present in an amount of 0.5% to 3% (w/w).

In an aspect of the present invention, the filler is aluminum silicate, present in Q.S.

In another aspect of the present invention provides a process for the preparation of a wettable powder composition comprising of pinoxaden and metribuzin, wherein the process comprises the following steps:
a) weighing filler, wetting agent, dispersing agent, pinoxaden technical, metribuzin technical, and a defoamer in a pre-blender and mixing it for 1 hour,
b) milling the sample through air jet mill instrument at inlet pressure 2-3 kg/cm2, grinding pressure 6 kg/ cm2 and checking for the particle size < 15 micron,
c) collecting the milled material, and post blending the sample for 1 hour,
d) sending the sample to the quality analysis, and
e) packing the formulated material in a suitable package.

In yet another aspect of the present invention provides a synergistic herbicidal composition of pinoxaden and metribuzin with an improved stability and ready to use herbicidal composition, having superior bio-efficacy compared to the individual formulations.

DESCRIPTION OF THE INVENTION
The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. The present application is not intended to be limited to the embodiments shown but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.

Similarly, the words "comprise," "comprises," and "comprising" are to be interpreted inclusively rather than exclusively. Likewise, the terms "include," "including" and "or" should all be construed to be inclusive, unless such a construction is clearly prohibited from the context. However, the embodiments provided by the present disclosure may lack any element that is not specifically disclosed herein. Thus, a disclosure of an embodiment defined using the term "comprising" is also a disclosure of embodiments "consisting essentially of” and "consisting of” the disclosed components. Where used herein, the term "example," particularly when followed by a listing of terms, is merely exemplary and illustrative, and should not be deemed to be exclusive or comprehensive. Any embodiment disclosed herein can be combined with any other embodiment disclosed herein unless explicitly indicated 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.

The term “active ingredient” (a.i.) or “active agent” used herein refers to that component of the composition responsible for control of weeds, undesired vegetation, and grasses.

Unless otherwise specified, % refers to % weight; and % weight refers to % of the weight of the respective component with respect to the total weight of the composition.

As used herein, the term "effective amount" means the amount of the active substances in the compositions to achieve an observable effect on growth, including the effects of necrosis, death, retardation, prevention, and removal, destruction, or otherwise diminishing the occurrence and activity of the target weed. The effective amount can vary for the various compositions used in the present invention. An effective amount of the compositions will also vary according to the prevailing conditions such as desired herbicidal effect and duration, weather, target species, locus, mode of application, and the like. The terms plants, weeds and vegetation include germinant seeds, emerging seedlings, plants emerging from vegetative propagules and established vegetation.

As used herein, the term “agrochemical additives” may be understood to include a range of surfactants, dispersing agents, pigments, solvents, co-solvents, defoamers, 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 present invention aims to provide an herbicidal combination, which allows efficient and reliable control of grass and broadleaf weeds. Moreover, the persistence of the herbicidal activity of the combination should be sufficiently long to achieve control of the weeds over a sufficient long time thus allowing a more flexible application. The combination should also have a low toxicity to humans or other mammals. The combinations should also show an accelerated action on harmful plants, i.e., they should affect damaging of the harmful plants more quickly in comparison with application of the individual herbicides.

The active compounds within the herbicidal composition according to the invention have potent weedicide activity and can be employed for controlling undesired weeds, vegetation, and sedges.

The novel herbicidal composition of the present invention may be formulated as Granular composition (GR), Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro-emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) suspension, Tablet (TB), Ultra-low volume (ULV) liquid, Water dispersible granules (WG), Wettable powder (WP), Water dispersible powder for slurry seed treatment (WS), Water dispersible tablet (WT), a mixed formulation of CS and SC (ZC), a mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW). Preferably, the composition of the present invention is formulated as wettable powder (WP).

In one embodiment of the present invention provides a synergistic herbicidal composition comprising of:
a) pinoxaden in a range from 1% (w/w) to 10% (w/w),
b) metribuzin in a range from 20% (w/w) to 30% (w/w), and
c) agrochemical additives.

In another embodiment of the present invention, provides a wettable powder (WP) formulation of pinoxaden is present in a range from 1% (w/w) to 10% (w/w); and metribuzin is present in a range from 20% (w/w) to 30% (w/w) with one or more agrochemical additives.

Agrochemical additives may be a solid or liquid and are generally a substance commonly used in formulation processing process, for example, wetting agents, dispersing agents, defoamer, co-filler, anti-caking agent, and a filler.

Wetting is the first stage of dispersion, in which air surrounding the granular composition is substituted with water. Wetting of the composition with water cannot occur if the surface tension of the liquid is very high. Hence, it is recommended to add a wetting agent to the composition to facilitate the process of dispersion of the granules in the liquid. The wetting agent is selected from the group comprising of an anionic sodium diisopropyl naphthalene sulfonate, dialkyl naphthalene sulphonate sodium salt, Propol 990N, Sodium salt of dibutyl naphthalene sulphonate, and sodium methyl cocoyl taurate. Preferably, the wetting agent suitable for use in the present invention are an anionic sodium diisopropyl naphthalene sulfonate, Propol 990N and sodium methyl cocoyl taurate, present in a range from 1% to 10% (w/w).

It is generally observed that solid particles in a liquid undergo spontaneous aggregation to form lumps. Hence it is recommended to add a dispersing agent which prevents agglomeration of solid particles and keeps them suspended in fluid. Accordingly, the composition of the present invention contains dispersing agents such as alkyl naphthalene sulfonate, alkyl naphthalene sulfonate condensate, sodium lignosulfonate, and sodium polycarboxylate. The dispersing agents are present in a range from 5% to 15% (w/w).

Defoamer is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. Accordingly, the composition of the present invention contains a polydimethyl siloxane as a defoamer, present in a range from 0.1% to 1.5% (w/w).

An anticaking agent is an additive placed in powdered or granulated materials, to prevent the formation of lumps (caking) and for easing packaging, transport, flowability, and consumption. Accordingly, the composition of the present invention contains silicon dioxide as an anticaking agent, present in a range from 0.5% to 3% (w/w).

As used herein, the term “co-filler” refers to solid chemicals that are added to an herbicide formulation to aid in the delivery of the active ingredient. Accordingly, the composition of the present invention contains a co-filler selected from the lactose monohydrate, ammonium sulphate and a combination thereof, present in a range from 1% to 10% (w/w).

As used herein, the term “filler” refers to solid chemicals that are added to an herbicide formulation to aid in the delivery of the active ingredient. Filler is selected from the group comprising of natural minerals such as corn starch, lactose monohydrate, quartz, talc, kaolin, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, fumed silica, sodium silicate, alumina, aluminum silicate, aluminum hydroxide; inorganic salts such as calcium carbonate, ammonium sulfate or other ammonium salts, sodium sulfate, potassium chloride. The filler may be used alone or in combination thereof. Preferably, the filler suitable for use in the present invention is aluminum silicate, present in Q.S.

In yet another embodiment of the present invention provides a process for preparation of composition of pinoxaden and metribuzin in wettable powder (WP) form is prepared by the following steps:
a) weighing filler, wetting agent, dispersing agent, pinoxaden technical, metribuzin technical, and a defoamer in a pre-blender and mixing it for 1 hour,
b) milling the sample through air jet mill instrument at inlet pressure 2-3 kg/cm2, grinding pressure 6 kg/ cm2 and checking for the particle size < 15 micron,
c) collecting the milled material, and post blending the sample for 1 hour,
d) sending the sample to the quality analysis, and
e) packing the formulated material in a suitable package.

The herbicide compositions of the present invention can be applied to a variety of undesired vegetation in both residential and commercial plant or crop areas. Preferably, the herbicide compositions are effective to selectively control broadleaf weeds growing in grass and turf areas. The herbicidal compositions disclosed herein are very effective against numerous common broadleaf weeds, mosses, liverworts, and algae. Grass and turf areas that are infested with undesired vegetation can be entirely sprayed with an herbicidal composition of the present invention to selectively remove the unwanted vegetation, while leaving the grass, turf, and other desired plants undamaged.

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 present invention is further illustrated by the following examples which are provided merely to be exemplary of the inventions and is not intended to limit the scope of the invention. Certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.

EXAMPLES:
Example-1: The illustrative embodiments show the composition of Pinoxaden and Metribuzin, in wettable powder form in different amount as follows:

Table-1: Pinoxaden 3.2% + Metribuzin 21% (w/w) wettable powder (WP)
S. No Compositions Function Charge in (%)
1. Pinoxaden Active ingredient 3.2
2. Metribuzin Active ingredient 21.0
3. Anionic sodium diisopropyl naphthalene sulfonate Wetting agent 5.0
4. Alkyl naphthalene sulfonate Dispersing agent 12.0
5. Polydimethylsiloxane Defoamer 0.5
6. Aluminium silicate
(China clay) Filler Q. S

Process for manufacture of composition is as follows:
3.2 gm of pinoxaden, 21.0 gm of metribuzin, 5.0 gm of Anionic sodium diisopropyl naphthalene sulfonate, 12.0 gm of alkyl naphthalene sulfonate, 0.5 gm of polydimethylsiloxane, and required quantity of aluminum silicate (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 kg/ cm2) to obtain the desired particle size (D90 < 15 microns). Collecting the milled material and post blending the material for 1 hour followed by packing the material in a suitable package.

Table-2: Pinoxaden 5 % + Metribuzin 25% (w/w) wettable powder (WP)
S. No Compositions Function Charge in (%)
1. Pinoxaden Active ingredient 5.0
2. Metribuzin Active ingredient 25.0
3. Anionic sodium diisopropyl naphthalene sulfonate Wetting agent 8.0
4. Alkyl naphthalene sulfonate condensate Dispersing agent 10.0
5. Polydimethylsiloxane Defoamer 0.8
6. Lactose monohydrate Co-filler 5.0
7. Ammonium sulphate Co-filler 10.0
8. Aluminium silicate (China clay) Filler Q. S

Process for manufacture of composition is as follows:
5.0 gm of pinoxaden, 25.0 gm of metribuzin, 8.0 gm of anionic sodium diisopropyl naphthalene sulfonate, 10.0 gm of alkyl naphthalene sulfonate condensate, 0.8 gm of polydimethylsiloxane, 5.0 gm of lactose monohydrate, 10.0 gm of ammonium sulphate, and required quantity of aluminum silicate (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 kg/ cm2) to obtain the desired particle size (D90 < 15 microns). Collecting the milled material and post blending the material for 1 hour followed by packing the material in a suitable package.

Table-3: Pinoxaden 2 % + Metribuzin 20% (w/w) wettable powder (WP)
S. No Compositions Function Charge in (%)
1. Pinoxaden Active ingredient 2.0
2. Metribuzin Active ingredient 20.0
3. Propol 990N Wetting agent 10.0
4. Sodium lignosulfonate Dispersing agent 15.0
5. Polydimethylsiloxane Defoamer 1.5
6. Aluminium silicate (China clay) Filler Q. S

Process for manufacture of composition is as follows:
2.0 gm of pinoxaden, 23.0 gm of metribuzin, 10.0 gm of Propol 990N, 15.0 gm of sodium lignosulfonate, 1.5 gm of polydimethylsiloxane, and required quantity of aluminum silicate (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 kg/ cm2) to obtain the desired particle size (D90 < 15 microns). Collecting the milled material and post blending the material for 1 hour followed by packing the material in a suitable package.

Table-4: Pinoxaden 6 % + Metribuzin 27% (w/w) wettable powder (WP)
S. No Compositions Function Charge in (%)
1. Pinoxaden Active ingredient 6.0
2. Metribuzin Active ingredient 27.0
3. Sodium salt of dibutyl naphthalene sulphonate Wetting agent 8.0
4. Sodium Polycarboxylate Dispersing agent 12.0
5. Polydimethylsiloxane Defoamer 1.2
6. Aluminium silicate (China clay) Filler Q. S

Process for manufacture of composition is as follows:
6.0 gm of pinoxaden, 27.0 gm of metribuzin, 8.0 gm of Sodium salt of dibutyl naphthalene sulphonate, 12.0 gm of Sodium Polycarboxylate, 1.2 gm of polydimethylsiloxane, and required quantity of aluminum silicate (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 kg/ cm2) to obtain the desired particle size (D90 < 15 microns). Collecting the milled material and post blending the material for 1 hour followed by packing the material in a suitable package.

Table-5: Pinoxaden 10 % + Metribuzin 30% (w/w) wettable powder (WP)
S. No Compositions Function Charge in (%)
1. Pinoxaden Active ingredient 10.0
2. Metribuzin Active ingredient 30.0
3. Sodium methyl cocoyl taurate Wetting agent 5.0
4. Alkyl naphthalene sulfonate Dispersing agent 8.0
5. Polydimethylsiloxane Defoamer 0.8
6. Silicon dioxide Anti caking agent 2.5
7. Lactose monohydrate Co-filler Q. S

Process for manufacture of composition is as follows:
10.0 gm of pinoxaden, 30.0 gm of metribuzin, 5.0 gm of Sodium methyl cocoyl taurate, 8.0 gm of alkyl naphthalene sulfonate, 0.8 gm of polydimethylsiloxane, 2.5 gm of silicon dioxide, and required quantity 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 kg/ cm2) to obtain the desired particle size (D90 < 15 microns). Collecting the milled material and post blending the material for 1 hour followed by packing the material in a suitable package.

Example 2: Efficacy study for combination: Pinoxaden + Metribuzin WP:

FIELD AND SYNERGY STUDIES:
Wheat is the main cereal crop in India. In India, it is grown on an area of 31.6 million hectare with an annual production of 106.84 million tons. Successful weed control is the most important factor for fruitful wheat production because losses due to weeds have been one of the major limiting factors in wheat production. Weeds compete with crops for light moisture and nutrients. It was concluded that weeds exhibit economic yield losses to the wheat crop, which may range from 24-39.95% and these must be controlled during the full growing season of the crop for achieving satisfactory crop yields. Traditionally, weed control in India has been largely dependent on manual weeding. However, increased labour scarcity and costs are encouraging farmers to adopt herbicides.

Field studies were conducted to compare the weed controlling activity of the combination of Pinoxaden & Metribuzin. The active ingredient Pinoxaden in the combination, belongs to the chemical class of phenyl pyrazolines and its mode of action is based on inhibition of the Acetyl-coenzyme A carboxylase. Pinoxaden is taken up via leaves and distributed by phloem and xylem within a plant (HOFER et al. 2005). Metribuzin belonging to chemical family “Triazinones” with PS II inhibitor (inhibition of photosystem-II) mode of action. Combination has the potential of controlling the cross-spectrum weeds (broad leaf weeds & grassy weeds) in wheat at the post-emergence (30-40 DAS or 10 days after 1st irrigation to wheat) application timing. All the molecules are safe to wheat when applied at their recommended dose rate in post-emergence (30-40 DAS or 10 days after 1st irrigation to wheat) 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 400 L of water spray volume per hectare at post-emergence 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 30 days after application. These observations are to be taken from the 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 the 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: Demonstrates synergy on weeds using the combination of Pinoxaden and Metribuzin in Post-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target weed was Phalaris minor, and the results are recorded in the below table.

Active
Dose (GAH) % Weed Control of Phalaris minor
Expected Observed
Pinoxaden 5.1% EC 32 60
Metribuzin 70% WP 210 65
Pinoxaden 3.2% + Metribuzin 21% WP 210 + 32 86 93
Ratio of O/E 1.08
WP – Wettable Powder; EC – Emulsion Concentrate; and GAH – Gram Active per Hectare.

The Phalaris minor control results in table 6 clearly demonstrates synergy between Pinoxaden, & Metribuzin in Post-emergence application timing. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 7: Demonstrates synergy on weeds using the combination of Pinoxaden & Metribuzin in Post-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target weed was Chenopodium album, and the results are recorded in the below table.

Active
Dose (GAH) % Weed Control of
Chenopodium album
Expected Observed
Pinoxaden 5.1% EC 32 35
Metribuzin 70% WP 210 88
Pinoxaden 3.2% + Metribuzin 21% WP 210 + 32 92.2 100
Ratio of O/E 1.08
WP – Wettable Powder; EC – Emulsion Concentrate; and GAH – Gram Active per Hectare.

The Chenopodium album control results in table 7 clearly demonstrates, synergy between Pinoxaden and Metribuzin in post-emergence application timing. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 8: Demonstrates synergy on weeds using the combination of Pinoxaden & Metribuzin in Post-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target weed was Melilotus alba, and the results are recorded in the below table.

Active
Dose (GAH) % Weed Control of
Melilotus alba
Expected Observed
Pinoxaden 5.1% EC 32 15
Metribuzin 70% WP 210 85
Pinoxaden 3.2% + Metribuzin 21% WP 210 + 32 87.8 98
Ratio of O/E 1.11
WP – Wettable Powder; EC – Emulsion Concentrate; and GAH – Gram Active per Hectare.

The Melilotus alba control results in table 8 clearly demonstrate synergy between Pinoxaden, & Metribuzin in Post-emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.

Table 9: Demonstrates synergy on weeds using the combination of Pinoxaden & Metribuzin in Post-emergence application window. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target weed was Rumex dentatus, and the results are recorded in the below table.

Active
Dose (GAH) % Weed Control of
Rumex dentatus
Expected Observed
Pinoxaden 5.1% EC 32 20
Metribuzin 70% WP 210 85
Pinoxaden 3.2% + Metribuzin 21% WP 210 + 32 88 95
Ratio of O/E 1.07
WP – Wettable Powder; EC – Emulsion Concentrate; and GAH – Gram Active per Hectare.

The Rumex dentatus control results in table 9 clearly demonstrates synergy between Pinoxaden, & Metribuzin in Post-emergence application window. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination. ,CLAIMS:WE CLAIM:

1. A synergistic herbicidal wettable powder (WP) composition comprising of:
a) pinoxaden in a range from 1% (w/w) to 10% (w/w),
b) metribuzin in a range from 20% (w/w) to 30% (w/w), and
c) agrochemical additives.

2. The herbicidal composition as claimed in claim 1, wherein the agrochemical additives are selected from a wetting agent, a dispersing agent, a defoamer, an anti-caking agent, a filler and co-filler.

3. The herbicidal composition as claimed in claim 2, wherein the wetting agent is selected from the group comprising of an anionic sodium diisopropyl naphthalene sulfonate, dialkyl naphthalene sulphonate sodium salt, Propol 990N, Sodium salt of dibutyl naphthalene sulphonate, and sodium methyl cocoyl taurate, present in a range from 1% to 10% (w/w).

4. The herbicidal composition as claimed in claim 2, wherein the dispersing agent is selected from the group comprising of alkyl naphthalene sulfonate, alkyl naphthalene sulfonate condensate, sodium lignosulfonate, and sodium polycarboxylate, present in a range from 5% to 15% (w/w).

5. The herbicidal composition as claimed in claim 2, wherein the defoamer is a polydimethyl siloxane as a defoamer, present in a range from 0.1% to 1.5% (w/w).

6. The herbicidal composition as claimed in claim 2, wherein the filler is selected from aluminum silicate, aluminum hydroxide, sodium silicate, and ammonium sulfate.

7. The herbicidal composition as claimed in claim 2, wherein the co-filler is selected from lactose monohydrate, ammonium sulphate and a combination thereof, present in a range from 1% to 10% (w/w).

8. The herbicidal composition as claimed in claim 2, wherein the anticaking agent is silicon dioxide, present in a range from 0.5% to 3% (w/w).

9. The process for preparation of a wettable powder composition as claimed in claim 1, where in the process comprising the steps of:
a. weighing all this raw material filler, wetting agent, dispersing agent, pinoxaden technical, metribuzin technical, and a defoamer in a pre-blender and mixing it for 1 hour.
b. milling the sample through air jet mill instrument at inlet pressure 2-3 kg/cm2, grinding pressure 6 kg/ cm2 and checking for the particle size < 15 micron.
c. collecting the milled material, and post blending the sample for 1hr.
d. sending the sample to the quality analysis, and
e. packing the formulated material in a suitable package.

Dated this Thirtieth (30th) day of September, 2023

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