Indian Patents. 243753:A HERBICIDAL COMPOSITION COMPRISING CLODINAFOP-PROPARGYL AND METSULFURON-METHYL

Title of Invention	A HERBICIDAL COMPOSITION COMPRISING CLODINAFOP-PROPARGYL AND METSULFURON-METHYL
Abstract	A herbicidal composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous coating of hydrophobic inert material provided thereon and processes for the preparation thereof.

Full Text	F O R M 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2006 PROVISIONAL SPECIFICATION (See section 10; rule 13) 1. Title of the invention. “HERBICIDAL COMPOSITION” 2. Applicant(s) (a) NAME : United Phosphorus Ltd.(b) NATIONALITY : Indian (c) ADDRESS : Registered Office at 3-11, Office at Uniphos House, Mumbai - 400052, India GIDC, Vapi-396195 11th road, C.D.Marg, , Gujarat and Khar west, Field of the Invention The present invention relates generally to herbicidal compositions. More particularly, the present invention relates to an herbicidal composition that enables a simultaneous reduction of grassy and broadleaf weed population in a crop field. Background of the Invention An herbicide is used to kill unwanted plant weeds in a crop field. A primary consideration for a substance to be used as an herbicide requires the substance to be selective in killing specific targets while being capable of leaving the desired crop unharmed. Many modern chemical herbicides for agriculture are specifically formulated to decompose within a short period after application. This is desirable as it allows crops which may be affected by the herbicide to be grown on the land in future seasons. However, it has been seen that herbicides with low residual activity i.e. those which decompose quickly often do not provide season-long weed control. Therefore, there is a continuous need in the art to provide agricultural compositions that decompose within a predetermined time after application to the crop field but at the same time are stable enough to possess an appreciable efficacy in removing unwanted weeds. United States Patent No. 4 713 109 teaches a 2-propynyl ester of the compound 2- (4-(3-Chloro-5-fluoro-2-pyridyloxy)-phenoxy-propionic acid, which is commonly known as clodinafop-propargyl, a compound possessing demonstrated herbicidal activity specially in cereals, rice, wheat and soybeans crops. It is a member of the oxy phenoxy acid ester class of herbicides. It is known that clodinafop propargyl interacts with and inhibits the acetyl co-enzyme A carboxylase, which is essential for the production of lipids (fatty acids) needed for plant growth. The selectivity of this herbicide is based on the difference in the speed of herbicide breakdown in the crop versus the weeds. Clodinafop-propargyl converts from the ester form to the active acid and then to biologically inactive compounds. Grass weeds such as wild oats and wild millet cannot effectively break down clodinafop-propargyl, so they are controlled as a lethal dose accumulates at the meristematic growing points. This herbicide is known to control grasses such as green foxtail, barnyard grass, Persian darnel and volunteer canary seed in wheat crops. However, it is known that clodinafop propargyl is ineffective against several broadleaved weeds. US 4 881 966 teaches a composition comprising clodinafop-propargyl and a safener, which is cloquintocet-mexyl that accelerates the rate of clodinafop-propargyl break down in wheat, thus preventing the accumulation of a lethal dose. However, the disclosed composition is still not effective in controlling the growth of the broadleaved weeds. Metsulfuron methyl, having the chemical formula methyl 2-(4-methoxy-6-methyl-l ,3,5-triazin-2-ylcarbamoylsulfamoyl)benzoate is a pre and post emergence herbicide commonly used in forestry and vegetation management. It is a selective systemic herbicide absorbed through the roots and foliage, with rapid translocation both acropetally and basipetally. Susceptible plants cease growth almost immediately after post-emergence treatment and are killed in 7-21 days. It is known that surfactants increase the activity of metsulfuron-methyl selectively to certain broadleaved weeds to which clodinafop-propargyl is generally ineffective. US Patent No. 6 479 432 discloses a liquid composition comprising a first active ingredient selected from sulfonylureas in combination with an additional active ingredient. The sulfonylurea may be metsulfuron methyl whereas the disclosed list of additional active ingredients includes clodinafop-propargyl among a plurality of other herbicidal active agents. However, this US patent does not enable a composition comprising metsulfuron methyl and clodinafop propargyl as these two herbicides are per se found incompatible with each other. In fact the prior art discloses that tank mix spray of metsulfuron with clodinafop resulted in antagonism thereby significantly reducing the efficacy of grass herbicides. It was found that in compositions comprising clodinafop-propargyl and metsulfuron methyl, the latter active ingredient was found to be very unstable aggravated by the presence of the former. Numerous attempts have been made in the art to provide a composition including a combination of the two active ingredients but all these attempts have been largely unsuccessful not only because of the antagonism existing between the two compounds but also because of formulation incompatibilities between clodinafop and metsulfuron. Clodinafop-propargyl is known to be stable in acidic environment whereas metsulfuron methyl is known to be stable in neutral to alkaline pH conditions. It was found that the presence of clodinafop-propargyl destroys the relative smaller amount of metsulfuron methyl, which mechanism is generally believed to aggravate the compatibility between the two active ingredients in combination. There were also strong antagonistic effects of metsulfuron on the performance of clodinafop resulting in tremendous reduction of efficacy of clodinafop. However, a compatible composition comprising clodinafop-propargyl and metsulfuron methyl has been desirable, but hitherto not been made possible, as they display complementary benefits of reducing grass weeds and broadleaved weeds respectively. Thus, there exists a need within the art for a composition comprising clodinafop-propargyl and metsulfuron methyl having an enhanced compatibility between the two active ingredients and which shows superior and desirable weed control benefits. Objects of the Invention: Accordingly, it is an object of the present invention to provide a composition comprising clodinafop-propargyl and metsulfuron methyl having an enhanced compatibility between the two ingredients such that the stability of metsulfuron methyl is not compromised owing to the presence of clodinafop-propargyl. Another object of the present invention to provide a composition comprising clodinafop-propargyl and metsulfuron methyl wherein each active ingredient displays an improved herbicidal activity in controlling the growth of grassy and broad leaf weeds in crops. Another object of the present invention is to provide a herbicidal composition that enables a simultaneous control of grassy and broadleaf weed population in a crop field. Yet another object of the present invention is to provide a herbicidal composition that affords an increased grain yield at a predetermined dosage of the composition to the crop field. Another object of the present invention is to provide a herbicidal composition that enhances performance of weed control thereby reducing the required application frequency of the composition to control the grassy and broadleaved weeds in a crop field. Another object of the present invention is to provide a herbicidal composition which demonstrates a complementation of weed control activity over the application of individual herbicides separately. Yet another advantage of the present invention is to provide a metsulfuron methyl particulate form that is stable in presence of clodinafop-propargyl. Summary of the Invention Accordingly, in one aspect, the present invention provides metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material. In yet another aspect, the present invention provides a herbicidal composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous barrier coating of hydrophobic inert material provided thereon. Detailed description of the Invention In accordance with a first aspect of the present invention, there is provided metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material. It has been found by the present inventors that providing a homogenous coating on metsulfuron methyl particles with hydrophobic inert material confers an enhanced stability to the coated metsulfuron methyl in presence of clodinafop-propargyl. Without wishing to be bound by theory, it is believed that the coating of hydrophobic inert material to the metsulfuron methyl active ingredient particles creates a protective barrier around the particles. The protective barrier thus formed protects the active ingredient, and particularly protects the sulfonyl urea bridge present in metsulfuron methyl, from coming into contact with other excipients or other active ingredients such as clodinafop-propargyl which are responsible for the reduced stability of the metsulfuron methyl particles. In an embodiment, said metsulfuron methyl particles have a particle size of about 2 microns to about less than 200 microns. Preferably, said particles have a particle size of about less than 20 microns. In another embodiment of this aspect of the present invention, said hydrophobic inert material chosen from polymers, clays, silica, silicone derivatives, modified cellulose, modified starches, natural and /or synthetic waxe(s), paraffin, paraffin liquid, wax and oils. In another aspect, the present invention provides a process for preparing metsulfuron methyl active ingredient particles having an enhanced stability in presence of clodinafop-propargyl, said process comprising grinding provided metsulfuron methyl particles to a predetermined particle size and mixing said ground metsulfuron methyl particles in a predetermined quantity with a hydrophobic inert material to obtain homogenous hydrophobic coated particles of metsulfuron methyl. In an embodiment, said metsulfuron methyl particles are ground to a particle size of about 2 microns to about less than 200 microns . Preferably, said particles are ground to a particle size of about less than 20 microns. In yet another aspect, the present invention provides a herbicidal composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous coating of hydrophobic inert material provided thereon. In an embodiment of this aspect of the present invention, said metsulfuron methyl particles have a particle size of about 2 microns to about less than 200 microns. Preferably, said particles have a particle size of about less than 20 microns. In a preferred embodiment, clodinafop-propargyl active ingredient comprises about 0.1 to 50% and preferably 1.0 to 40% of the total weight of the composition. In another preferred embodiment, clodinafop-propargyl is present in an amount of about 2 to 30 % by total weight of the composition. In another preferred embodiment, metsulfuron methyl active ingredient comprises about 0.01 to 40% and preferably 0.1%> to 35% of the total weight of the composition. In another preferred embodiment, metsulfuron methyl is present in an amount of about 0.1 to 30.0 % by total weight of the composition. Without being bound by theory, it is believed that the coating of hydrophobic inert material to the metsulfuron methyl active ingredient particles creates a protective barrier around the particles. The protective barrier thus formed protects the active ingredient, and particularly protects the sulfonyl urea bridge present in metsulfuron methyl, from coming into contact with clodinafop-propargyl which is responsible for the reduced stability of the metsulfuron methyl particles to acidic pH conditions thereby fulfilling a long felt need in the art of providing a stable composition comprising metsulfuron methyl and clodinafop-propargyl. In another embodiment, the composition comprises a safener Cloquintocet-mexyl that accelerates the rate of clodinafop-propargyl break down in crop, thus preventing the accumulation of a lethal dose. In a preferred embodiment, said safener is present in an amount of about 1% to about 50% by total weight of the clodinafop-propargyl. In another preferred embodiment, said safener is present in amount of about 0.01 to 25 %, and preferably about 1.02 to 15 % by total weight of the composition. In another preferred embodiment, said composition includes at least one ingredient selected from a dispersing agent, a wetting/dispersing agent, a stabilizer and an inert ingredient. The dispersing agent is preferably used in an amount of about 0.1 to about 40.0 %, and preferably from about 1.0 to about 30.0 % by total weight of the composition. In another preferred embodiment, the dispersing agent is present in an amount of about 2.0 to 20.0 % by total weight of the composition. The dispersing agent may be preferably selected from a group comprising lignosulphonates, phenyl naphthalene sulphonates, ethoxylated alkyl phenols, ethoxylated fatty acids, alkoxylated linear alcohols, polyaromatic sulfonates, sodium alkyl aryl sulfonates, maleic anhydride copolymers, phosphate esters, condensation products of aryl sulphonic acids and formaldehyde, addition products of ethylene oxide and fatty acid esters, sulfonates of condensed naphthalene, lignin derivatives, naphthalene formaldehyde condensates, polycarboxylates, sodium alkyl benzene sulfonates, salts of sulfonated naphthalene, ammonium salts of sulfonated naphthalene, salts of polyacrylic acids and salts of phenol sulfonic acids . In a preferred embodiment, the dispersing agent is sulphated poly aryl alkyl ethoxylate ammonium salt. The wetting/dispersing agent is preferably used in an amount of about 0.5 to about 30.0 %, and preferably from about 1.0 to about 30.0 % by total weight of the composition. In another preferred embodiment, the wetting/dispersing agent is present in an amount of about 2.0 to 25.0 % by total weight of the composition. The wetting/dispersing agent may be preferably selected from a group comprising alkyl phenol ethoxylate, fatty oil ethoxylate, phenyl naphthalene sulphonates, alkyl naphthalene sulfonates, sodium alkyl naphthalene sulfonate, sodium salt of sulfonated alkyl carboxylate, polyoxyalkylatd ethyl phenols, polyoxyethoxylated fatty alcohols, polyoxyethoxylated fatty amines, lignin derivatives, alkane sulfonates, alkylbenzene sulfonates, salts of polycarboxylic acids, salts of esters of sulfosuccinic acid, alkylnaphthalenesulfonates, alkylbenzenesulfonates, alkylpolyglycol ether sulfonates, alkyl ether phosphates, alkyl ether sulfates and alkyl sulfosuccinic monoesters. In a preferred embodiment, the wetting agent is a mixture of alkyl phenol ethoxylate and fatty oil ethoxylate, wherein alkyl phenol ethoxylate is present in an amount of about 16.00 % and fatty oil ethoxylate is present in amount of about 1.5% by total weight of the composition. It was found that in compositions comprising the dispersing and wetting/dispersing agents such as hereinabove described, the composition particles did not exhibit any flocculation tendencies which was observed with hitherto known compositions. It was further found that the absence of the flocculation tendencies was observed with the specific choice of a mixture of alkyl phenol ethoxylate and fatty oil ethoxylate as the wetting/dispersing agent which therefore form a preferred embodiment of the wetting/dispersing agents described herein. The compositions of the present invention further include a stabilizer. The stabilizer is preferably used in an amount of about 0.01 to about 20.0 %, and preferably from about 0.05 to about 18.0 % by total weight of the composition. In another preferred embodiment, the stabilizer is present in an amount of about 0.1 to 15.0 % by total weight of the composition. The stabilizer may be preferably selected from a group comprising epoxidized soybean oil, gamma butyrolactone, butylated hydroxyl toluene and its derivatives, epichlorhydrin, buffering agents, quinone derivatives, hydrazine hydrates and its derivatives, general class UV stabilizers, glycols and its derivatives and mixtures thereof. The compositions according to the present invention further comprise an inert ingredient present in an amount of about 10.0 to about 99.0 % and preferably about 15.0 to about 98.0 % of the total weight of the composition. In a further preferred embodiment, the compositions of the present invention comprise an inert ingredient in an amount of from about 20.0 to about 95.0 % by weight of the composition. In a preferred embodiment, the inert ingredient is chosen from a group comprising polymers, clays, silica, modified cellulose, modified starches, silicone derivatives, natural and /or synthetic waxe(s), paraffins, paraffin liquids, wax and oils, which ingredient is believed to form a protective coating such as hereinabove described on the metsulfuron methyl particles. The compositions of the present invention may be preferably formulated as wettable powders though other formulations such as ready to spray suspensions and emulsions are also included. The wettable powder of the present invention may be suitably dispersed in water at a suitable proportion to provide aqueous compositions that can be applied at a suitable spray rate. In a most preferred embodiment, the present invention provides a composition comprising about 15% total w/w of clodinafop-propargyl, about 3.75 % total w/w of Cloquintocet mexyl safener, about 1% total w/w of metsulfuron methyl, about 4 % total w/w of a dispersing agent, about 17.5 % total w/w of a wetting/dispersing agent, about 4% total w/w of a stabilizer and about 8% total w/w of a barrier forming inert material and approximately 45 % inert material wherein said methsulfuron methyl is provided in a particulate form having a substantially homogenous coating of said hydrophobic inert material provided thereon. In another aspect, the present invention provides a process for the preparation of a herbicidal composition, said process comprising: (a) grinding provided metsulfuron methyl to a predetermined particle size; (b) mixing said ground metsulfuron methyl particles with a selected inert material to form a barrier to obtain homogenous coated particles of metsulfuron methyl; (c) melting clodinafop-propargyl with cloquintocet mexyl in predetermined quantities; (d) adding the melted product of steps (c) with suitable dispersing agents, wetting agents and stabilizers; (e) heating the product of step (d) above to obtain a homogenous clodinafop liquid mixture, comprising Clodinafop-propargyl, being substantially free of solid particles; (f) maintaining the temperature of the liquid mixture obtained in step (e) from about 35 to about 80 °C; (g) spraying the hot clodinafop liquid mixture obtained in the step (f), over inert carriers (like precipitated silica); (h) mixing the product of the step (g) for an additional predetermined amount of time to obtain Clodinafop pre-mix in a free flowing powder form; and (i) mixing a predetermined quantity of homogenous coated particles of metsulfuron methyl (obtained in step (b) above) and Clodinafop pre-mix (obtained in step (h) above) in a suitable mixing equipment to obtain the composition. The process disclosed above may be conveniently employed to provide compositions having the following amounts of the ingredients: S. No. Ingredient(s) Range (%) 1 Clodinafop-propargyl 0.10 to 50.00 2 Cloquintocet mexyl 0.01 to 25.00 3 Metsulfuron methyl 0.01 to 40.00 4 Dispersing agent 0.10 to 40.00 5 Wetting/dispersing agent 0.50 to 30.00 6. Stabilizer 0.01 to 20.00 7. Inert ingredient(s) Q.S. Total 100.000 % The invention shall now be described with reference to the following non-limiting and exemplary embodiments. Example 1 The provided metsulfuron methyl was ground to a particle size of average 20 micron. The ground metsulfuron methyl was mixed in required quantity with the modified silicone dioxide inert material in a suitable blender to have the homogenous powder of Metsulfuron-methyl pre mix. The provided Clodinafop propargyl was melted with cloquintocet mexyl in required quantity. The above melted product was added with with sulphated poly aryl alkyl ethoxylate ammonium salt, fatty -oil ethoxylate, alkyl phenol ethoxylate and epoxydised fatty oil and heated to obtain a homogenous Clodinafop liquid mixture, free from solid particles. The temperature of Clodinafop liquid mixture was maintained between 35 to 80 °C. The molten clodinafop liquid mixture was sprayed over the precipitated silica in a suitable mixing equipment. The product of the above step was mixed for an additional time to finally obtain Clodinafop pre-mix in a free flowing powder form. A required quantity of Metsulfuron methyl pre-mix and Clodinafop pre-mix were mixed in a suitable mixer. The homogeneity of the product was confirmed by known quality assurance techniques. The approved product was thereafter packed in required pack sizes. The amount of the various ingredients were used according to the following exemplary and non-limiting composition. s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl 15.00 2 Cloquintocet mexyl 3.75 3 Metsulfuron methyl 1.00 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Fatty -oil ethoxylate 1.500 b) Alkyl phenol ethoxylate 16.000 6. Stabilizer (Epoxydised fatty oil) 4.000 7. Inert ingredient(s) a) modified silicone di-oxide 8.000 b) precipitated silica 46.75 Total 100.000 gm The process outlined above was employed to provide exemplary compositions according to the present invention having the following ingredients in the indicated relative percentages: Example -2 S. \| Ingredient(s) \| Quantity (gm) No. 1 Clodinafop-propargyl (active content) 15.00 2 Cloquintocet mexyl 3.75 3 Metsulfuron methyl (active content) 1.00 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Fatty -oil ethoxylate 1.500 b) Alkyl phenol ethoxylate 16.000 6. Stabilizer (Epoxydised fatty oil) 4.000 7. Inert ingredient(s) a) modified silicone di-oxide 8.000 b) Colloidal silica 46.75 Total 100.000 gm Example - 3 s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790 2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948 3 Metsulfuron methyl purity 95% (base 1.0%) 1.053 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Castor -oil ethoxylate -40 mole 1.500 b) Ethoxylated alkyl phenol 16.000 6. Stabilizer (Epoxydised soya bean oil) 4.000 7. Inert ingredient(s) a) hydrophobic silica powder 8.000 b) colloidal silica 45.709 Total 100.000 gm Example -4 s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl purity 95%) (base 15.0%) 15.790 2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948 3 Metsulfuron methyl purity 95% (base 1.0%) 1.053 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Castor -oil ethoxylate -40 mole 1.500 b) Ethoxylated alkyl phenol 16.000 6. Stabilizer (Epoxydised soya bean oil) 4.000 7. Inert ingredient(s) a) Polyvinyl pyrrolidone 5.000 b) colloidal silica 48.709 Example - 5 s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790 2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948 3 Metsulfuron methyl purity 95% (base 1.0%) 1.053 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Castor -oil ethoxylate -40 mole 1.500 b) Ethoxylated alkyl phenol 16.000 6. Stabilizer (Epoxydised soya bean oil) 4.000 7. Inert ingredient(s) a) Polyvinyl pyrrolidone 8.000 b) colloidal silica 45.709 Total 100.000 gm Example -6 s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790 2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948 3 Metsulfuron methyl purity 95% (base 1.0%) 1.053 4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000 5 Wetting/dispersing agent a) Castor -oil ethoxylate -40 mole 1.500 b) Ethoxylated alkyl phenol 16.000 6. Stabilizer (Epoxydised soya bean oil) 4.000 7. Inert ingredient(s) a) Polyvinyl pyrrolidone 10.000 b) colloidal silica 43.709 Total 100.000 gm Example-7 s.No. Ingredient(s) Quantity (gm) 1 Clodinafop-propargyl purity 95% (base 10.0%) 10.526 2 Cloquintocet mexyl purity 94 % (base 2.50%) 2.660 3 Metsulfuron methyl purity 95% (base 2.0%) 2.105 4 Dispersing agent (Sulphated poly aryl alkyl 3.500 ethoxylate ammonium salt)) 5 Wetting/dispersing agent a) Castor -oil ethoxylate -40 mole 1.500 b) Ethoxylated alkyl phenol 22.000 6. Stabilizer (Epoxydised soya bean oil) 4.000 7. Inert ingredient(s) a) modified silicone di-oxide 12.000 b) Colloidal silica 41.709 Total 100.000 gm Field Trial Field tests of the compositions according to the present invention were made at various controlled trial sites. The performance of the combination herbicide according to the present invention (Clodinafop 15 % and metsulfuron methyl 1%) was compared against the known compositions of Metsulfuron methyl 20% wettable powders and Clodinafop-propargyl 15% wettable powders, which were evaluated against weed flora in wheat crop during rabi season. The recommended package of practices for wheat crop was followed to raise the crop. The herbicide treatments were applied as post emergence spray at 35 days after sowing (DAS). The data on weed population (number/m2) and dry matter (gm/m2) was taken after 60 days after sowing and at the harvest. Similar yields (q/ha.) and yield attributed parameters like plant height, number of effective tiller, no. of grain per ear-head, test weight were recorded at harvest. A statistical analysis of the entire data was carried out. Phytotoxicity studies were also conducted on a rating scale of 0-10 for treatments of the compositions of the present invention @ 320 gm/acre (double the recommended dose) and Metsulfuron methyl @ 16 gm/acre (double the recommended dose). The major weed flora recorded in the experimental field were grasses like Phalaris minor and Avena fatua and broad leaf weeds namely Chenopodium album, Rumex sp., Convolvulus arvensis, Melilotus alba, Medicago denticulata, Fumaria sp. Vicia sativa and Anagalis arvensis. The trial surprisingly demonstrated that the compositions of the present invention at 160 gm/acre were the most effective and ideal treatment in controlling complex weed flora in wheat. The superiority of the treatment is clearly depicted in the lowest weed population, dry weight of weeds and highest grain yield. The data clearly shows that metsulfuron methyl gave superior control of broad leaf weeds only. Wherein the aforegoing reference has been made to components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described aspects and embodiments of the invention without departing from the principles taught herein. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims. ABSTRACT Disclosed are metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material. Also disclosed is a composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous coating of hydrophobic inert material provided thereon and processes for the preparation thereof.

Full Text

F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2006
PROVISIONAL SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. “HERBICIDAL COMPOSITION”

2. Applicant(s)
(a) NAME : United Phosphorus Ltd.(b) NATIONALITY : Indian
(c) ADDRESS : Registered Office at 3-11, Office at Uniphos House, Mumbai - 400052, India GIDC, Vapi-396195 11th road, C.D.Marg, , Gujarat and Khar west,

Field of the Invention
The present invention relates generally to herbicidal compositions. More particularly, the present invention relates to an herbicidal composition that enables a simultaneous reduction of grassy and broadleaf weed population in a crop field.
Background of the Invention
An herbicide is used to kill unwanted plant weeds in a crop field. A primary consideration for a substance to be used as an herbicide requires the substance to be selective in killing specific targets while being capable of leaving the desired crop unharmed. Many modern chemical herbicides for agriculture are specifically formulated to decompose within a short period after application. This is desirable as it allows crops which may be affected by the herbicide to be grown on the land in future seasons. However, it has been seen that herbicides with low residual activity i.e. those which decompose quickly often do not provide season-long weed control. Therefore, there is a continuous need in the art to provide agricultural compositions that decompose within a predetermined time after application to the crop field but at the same time are stable enough to possess an appreciable efficacy in removing unwanted weeds.
United States Patent No. 4 713 109 teaches a 2-propynyl ester of the compound 2- (4-(3-Chloro-5-fluoro-2-pyridyloxy)-phenoxy-propionic acid, which is commonly known as clodinafop-propargyl, a compound possessing demonstrated herbicidal activity specially in cereals, rice, wheat and soybeans crops. It is a member of the oxy phenoxy acid ester class of herbicides. It is known that clodinafop propargyl interacts with and inhibits the acetyl co-enzyme A carboxylase, which is essential for the production of lipids (fatty acids) needed for plant growth. The selectivity of this herbicide is based on the difference in the speed of herbicide breakdown in the crop versus the weeds. Clodinafop-propargyl converts from the ester form to the active acid and then to biologically inactive compounds. Grass weeds such as wild oats and wild millet cannot effectively break down clodinafop-propargyl, so they are controlled as a lethal dose accumulates at the meristematic growing points. This herbicide is known to control grasses such as green foxtail, barnyard grass, Persian

darnel and volunteer canary seed in wheat crops. However, it is known that clodinafop propargyl is ineffective against several broadleaved weeds.
US 4 881 966 teaches a composition comprising clodinafop-propargyl and a safener, which is cloquintocet-mexyl that accelerates the rate of clodinafop-propargyl break down in wheat, thus preventing the accumulation of a lethal dose. However, the disclosed composition is still not effective in controlling the growth of the broadleaved weeds.
Metsulfuron methyl, having the chemical formula methyl 2-(4-methoxy-6-methyl-l ,3,5-triazin-2-ylcarbamoylsulfamoyl)benzoate is a pre and post emergence herbicide commonly used in forestry and vegetation management. It is a selective systemic herbicide absorbed through the roots and foliage, with rapid translocation both acropetally and basipetally. Susceptible plants cease growth almost immediately after post-emergence treatment and are killed in 7-21 days. It is known that surfactants increase the activity of metsulfuron-methyl selectively to certain broadleaved weeds to which clodinafop-propargyl is generally ineffective.
US Patent No. 6 479 432 discloses a liquid composition comprising a first active ingredient selected from sulfonylureas in combination with an additional active ingredient. The sulfonylurea may be metsulfuron methyl whereas the disclosed list of additional active ingredients includes clodinafop-propargyl among a plurality of other herbicidal active agents. However, this US patent does not enable a composition comprising metsulfuron methyl and clodinafop propargyl as these two herbicides are per se found incompatible with each other. In fact the prior art discloses that tank mix spray of metsulfuron with clodinafop resulted in antagonism thereby significantly reducing the efficacy of grass herbicides.
It was found that in compositions comprising clodinafop-propargyl and metsulfuron methyl, the latter active ingredient was found to be very unstable aggravated by the presence of the former. Numerous attempts have been made in the art to provide a composition including a combination of the two active ingredients but all these attempts have been largely unsuccessful not only because of the antagonism existing

between the two compounds but also because of formulation incompatibilities between clodinafop and metsulfuron.
Clodinafop-propargyl is known to be stable in acidic environment whereas metsulfuron methyl is known to be stable in neutral to alkaline pH conditions. It was found that the presence of clodinafop-propargyl destroys the relative smaller amount of metsulfuron methyl, which mechanism is generally believed to aggravate the compatibility between the two active ingredients in combination. There were also strong antagonistic effects of metsulfuron on the performance of clodinafop resulting in tremendous reduction of efficacy of clodinafop. However, a compatible composition comprising clodinafop-propargyl and metsulfuron methyl has been desirable, but hitherto not been made possible, as they display complementary benefits of reducing grass weeds and broadleaved weeds respectively.
Thus, there exists a need within the art for a composition comprising clodinafop-propargyl and metsulfuron methyl having an enhanced compatibility between the two active ingredients and which shows superior and desirable weed control benefits.
Objects of the Invention:
Accordingly, it is an object of the present invention to provide a composition comprising clodinafop-propargyl and metsulfuron methyl having an enhanced compatibility between the two ingredients such that the stability of metsulfuron methyl is not compromised owing to the presence of clodinafop-propargyl.
Another object of the present invention to provide a composition comprising clodinafop-propargyl and metsulfuron methyl wherein each active ingredient displays an improved herbicidal activity in controlling the growth of grassy and broad leaf weeds in crops.
Another object of the present invention is to provide a herbicidal composition that enables a simultaneous control of grassy and broadleaf weed population in a crop field.

Yet another object of the present invention is to provide a herbicidal composition that affords an increased grain yield at a predetermined dosage of the composition to the crop field.
Another object of the present invention is to provide a herbicidal composition that enhances performance of weed control thereby reducing the required application frequency of the composition to control the grassy and broadleaved weeds in a crop field.
Another object of the present invention is to provide a herbicidal composition which demonstrates a complementation of weed control activity over the application of individual herbicides separately.
Yet another advantage of the present invention is to provide a metsulfuron methyl particulate form that is stable in presence of clodinafop-propargyl.
Summary of the Invention
Accordingly, in one aspect, the present invention provides metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material.
In yet another aspect, the present invention provides a herbicidal composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous barrier coating of hydrophobic inert material provided thereon.
Detailed description of the Invention
In accordance with a first aspect of the present invention, there is provided metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material.

It has been found by the present inventors that providing a homogenous coating on metsulfuron methyl particles with hydrophobic inert material confers an enhanced stability to the coated metsulfuron methyl in presence of clodinafop-propargyl.
Without wishing to be bound by theory, it is believed that the coating of hydrophobic inert material to the metsulfuron methyl active ingredient particles creates a protective barrier around the particles. The protective barrier thus formed protects the active ingredient, and particularly protects the sulfonyl urea bridge present in metsulfuron methyl, from coming into contact with other excipients or other active ingredients such as clodinafop-propargyl which are responsible for the reduced stability of the metsulfuron methyl particles.
In an embodiment, said metsulfuron methyl particles have a particle size of about 2 microns to about less than 200 microns. Preferably, said particles have a particle size of about less than 20 microns.
In another embodiment of this aspect of the present invention, said hydrophobic inert material chosen from polymers, clays, silica, silicone derivatives, modified cellulose, modified starches, natural and /or synthetic waxe(s), paraffin, paraffin liquid, wax and oils.
In another aspect, the present invention provides a process for preparing metsulfuron methyl active ingredient particles having an enhanced stability in presence of clodinafop-propargyl, said process comprising grinding provided metsulfuron methyl particles to a predetermined particle size and mixing said ground metsulfuron methyl particles in a predetermined quantity with a hydrophobic inert material to obtain homogenous hydrophobic coated particles of metsulfuron methyl.
In an embodiment, said metsulfuron methyl particles are ground to a particle size of about 2 microns to about less than 200 microns . Preferably, said particles are ground to a particle size of about less than 20 microns.

In yet another aspect, the present invention provides a herbicidal composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous coating of hydrophobic inert material provided thereon.
In an embodiment of this aspect of the present invention, said metsulfuron methyl particles have a particle size of about 2 microns to about less than 200 microns. Preferably, said particles have a particle size of about less than 20 microns.
In a preferred embodiment, clodinafop-propargyl active ingredient comprises about 0.1 to 50% and preferably 1.0 to 40% of the total weight of the composition. In another preferred embodiment, clodinafop-propargyl is present in an amount of about 2 to 30 % by total weight of the composition.
In another preferred embodiment, metsulfuron methyl active ingredient comprises about 0.01 to 40% and preferably 0.1%> to 35% of the total weight of the composition. In another preferred embodiment, metsulfuron methyl is present in an amount of about 0.1 to 30.0 % by total weight of the composition.
Without being bound by theory, it is believed that the coating of hydrophobic inert material to the metsulfuron methyl active ingredient particles creates a protective barrier around the particles. The protective barrier thus formed protects the active ingredient, and particularly protects the sulfonyl urea bridge present in metsulfuron methyl, from coming into contact with clodinafop-propargyl which is responsible for the reduced stability of the metsulfuron methyl particles to acidic pH conditions thereby fulfilling a long felt need in the art of providing a stable composition comprising metsulfuron methyl and clodinafop-propargyl.
In another embodiment, the composition comprises a safener Cloquintocet-mexyl that accelerates the rate of clodinafop-propargyl break down in crop, thus preventing the accumulation of a lethal dose. In a preferred embodiment, said safener is present in an amount of about 1% to about 50% by total weight of the clodinafop-propargyl. In

another preferred embodiment, said safener is present in amount of about 0.01 to 25 %, and preferably about 1.02 to 15 % by total weight of the composition.
In another preferred embodiment, said composition includes at least one ingredient selected from a dispersing agent, a wetting/dispersing agent, a stabilizer and an inert ingredient.
The dispersing agent is preferably used in an amount of about 0.1 to about 40.0 %, and preferably from about 1.0 to about 30.0 % by total weight of the composition. In another preferred embodiment, the dispersing agent is present in an amount of about 2.0 to 20.0 % by total weight of the composition.
The dispersing agent may be preferably selected from a group comprising lignosulphonates, phenyl naphthalene sulphonates, ethoxylated alkyl phenols, ethoxylated fatty acids, alkoxylated linear alcohols, polyaromatic sulfonates, sodium alkyl aryl sulfonates, maleic anhydride copolymers, phosphate esters, condensation products of aryl sulphonic acids and formaldehyde, addition products of ethylene oxide and fatty acid esters, sulfonates of condensed naphthalene, lignin derivatives, naphthalene formaldehyde condensates, polycarboxylates, sodium alkyl benzene sulfonates, salts of sulfonated naphthalene, ammonium salts of sulfonated naphthalene, salts of polyacrylic acids and salts of phenol sulfonic acids . In a preferred embodiment, the dispersing agent is sulphated poly aryl alkyl ethoxylate ammonium salt.
The wetting/dispersing agent is preferably used in an amount of about 0.5 to about 30.0 %, and preferably from about 1.0 to about 30.0 % by total weight of the composition. In another preferred embodiment, the wetting/dispersing agent is present in an amount of about 2.0 to 25.0 % by total weight of the composition.
The wetting/dispersing agent may be preferably selected from a group comprising alkyl phenol ethoxylate, fatty oil ethoxylate, phenyl naphthalene sulphonates, alkyl naphthalene sulfonates, sodium alkyl naphthalene sulfonate, sodium salt of sulfonated alkyl carboxylate, polyoxyalkylatd ethyl phenols, polyoxyethoxylated fatty alcohols,

polyoxyethoxylated fatty amines, lignin derivatives, alkane sulfonates, alkylbenzene sulfonates, salts of polycarboxylic acids, salts of esters of sulfosuccinic acid, alkylnaphthalenesulfonates, alkylbenzenesulfonates, alkylpolyglycol ether sulfonates, alkyl ether phosphates, alkyl ether sulfates and alkyl sulfosuccinic monoesters. In a preferred embodiment, the wetting agent is a mixture of alkyl phenol ethoxylate and fatty oil ethoxylate, wherein alkyl phenol ethoxylate is present in an amount of about 16.00 % and fatty oil ethoxylate is present in amount of about 1.5% by total weight of the composition.
It was found that in compositions comprising the dispersing and wetting/dispersing agents such as hereinabove described, the composition particles did not exhibit any flocculation tendencies which was observed with hitherto known compositions. It was further found that the absence of the flocculation tendencies was observed with the specific choice of a mixture of alkyl phenol ethoxylate and fatty oil ethoxylate as the wetting/dispersing agent which therefore form a preferred embodiment of the wetting/dispersing agents described herein.
The compositions of the present invention further include a stabilizer. The stabilizer is preferably used in an amount of about 0.01 to about 20.0 %, and preferably from about 0.05 to about 18.0 % by total weight of the composition. In another preferred embodiment, the stabilizer is present in an amount of about 0.1 to 15.0 % by total weight of the composition.
The stabilizer may be preferably selected from a group comprising epoxidized soybean oil, gamma butyrolactone, butylated hydroxyl toluene and its derivatives, epichlorhydrin, buffering agents, quinone derivatives, hydrazine hydrates and its derivatives, general class UV stabilizers, glycols and its derivatives and mixtures thereof.
The compositions according to the present invention further comprise an inert ingredient present in an amount of about 10.0 to about 99.0 % and preferably about 15.0 to about 98.0 % of the total weight of the composition. In a further preferred embodiment, the compositions of the present invention comprise an inert ingredient in an amount of from about 20.0 to about 95.0 % by weight of the composition.

In a preferred embodiment, the inert ingredient is chosen from a group comprising polymers, clays, silica, modified cellulose, modified starches, silicone derivatives, natural and /or synthetic waxe(s), paraffins, paraffin liquids, wax and oils, which ingredient is believed to form a protective coating such as hereinabove described on the metsulfuron methyl particles.
The compositions of the present invention may be preferably formulated as wettable powders though other formulations such as ready to spray suspensions and emulsions are also included. The wettable powder of the present invention may be suitably dispersed in water at a suitable proportion to provide aqueous compositions that can be applied at a suitable spray rate.
In a most preferred embodiment, the present invention provides a composition comprising about 15% total w/w of clodinafop-propargyl, about 3.75 % total w/w of Cloquintocet mexyl safener, about 1% total w/w of metsulfuron methyl, about 4 % total w/w of a dispersing agent, about 17.5 % total w/w of a wetting/dispersing agent, about 4% total w/w of a stabilizer and about 8% total w/w of a barrier forming inert material and approximately 45 % inert material wherein said methsulfuron methyl is provided in a particulate form having a substantially homogenous coating of said hydrophobic inert material provided thereon.
In another aspect, the present invention provides a process for the preparation of a herbicidal composition, said process comprising:
(a) grinding provided metsulfuron methyl to a predetermined particle size;
(b) mixing said ground metsulfuron methyl particles with a selected inert material to form a barrier to obtain homogenous coated particles of metsulfuron methyl;
(c) melting clodinafop-propargyl with cloquintocet mexyl in predetermined quantities;
(d) adding the melted product of steps (c) with suitable dispersing agents, wetting agents and stabilizers;

(e) heating the product of step (d) above to obtain a homogenous clodinafop liquid mixture, comprising Clodinafop-propargyl, being substantially free of solid particles;
(f) maintaining the temperature of the liquid mixture obtained in step (e) from about 35 to about 80 °C;
(g) spraying the hot clodinafop liquid mixture obtained in the step (f), over inert carriers (like precipitated silica);
(h) mixing the product of the step (g) for an additional predetermined amount of time to obtain Clodinafop pre-mix in a free flowing powder form; and
(i) mixing a predetermined quantity of homogenous coated particles of metsulfuron methyl (obtained in step (b) above) and Clodinafop pre-mix (obtained in step (h) above) in a suitable mixing equipment to obtain the composition.
The process disclosed above may be conveniently employed to provide compositions having the following amounts of the ingredients:

S. No. Ingredient(s) Range (%)
1 Clodinafop-propargyl 0.10 to 50.00
2 Cloquintocet mexyl 0.01 to 25.00
3 Metsulfuron methyl 0.01 to 40.00
4 Dispersing agent 0.10 to 40.00
5 Wetting/dispersing agent 0.50 to 30.00
6. Stabilizer 0.01 to 20.00
7. Inert ingredient(s) Q.S.
Total 100.000 %
The invention shall now be described with reference to the following non-limiting and exemplary embodiments.
Example 1
The provided metsulfuron methyl was ground to a particle size of average 20 micron. The ground metsulfuron methyl was mixed in required quantity with the modified silicone dioxide inert material in a suitable blender to have the homogenous powder

of Metsulfuron-methyl pre mix. The provided Clodinafop propargyl was melted with cloquintocet mexyl in required quantity. The above melted product was added with with sulphated poly aryl alkyl ethoxylate ammonium salt, fatty -oil ethoxylate, alkyl phenol ethoxylate and epoxydised fatty oil and heated to obtain a homogenous Clodinafop liquid mixture, free from solid particles. The temperature of Clodinafop liquid mixture was maintained between 35 to 80 °C. The molten clodinafop liquid mixture was sprayed over the precipitated silica in a suitable mixing equipment. The product of the above step was mixed for an additional time to finally obtain Clodinafop pre-mix in a free flowing powder form. A required quantity of Metsulfuron methyl pre-mix and Clodinafop pre-mix were mixed in a suitable mixer. The homogeneity of the product was confirmed by known quality assurance techniques. The approved product was thereafter packed in required pack sizes. The amount of the various ingredients were used according to the following exemplary and non-limiting composition.

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl 15.00
2 Cloquintocet mexyl 3.75
3 Metsulfuron methyl 1.00
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Fatty -oil ethoxylate 1.500
b) Alkyl phenol ethoxylate 16.000
6. Stabilizer (Epoxydised fatty oil) 4.000
7. Inert ingredient(s)
a) modified silicone di-oxide 8.000
b) precipitated silica 46.75
Total 100.000 gm
The process outlined above was employed to provide exemplary compositions according to the present invention having the following ingredients in the indicated relative percentages:
Example -2
S. | Ingredient(s) | Quantity (gm)

No.
1 Clodinafop-propargyl (active content) 15.00
2 Cloquintocet mexyl 3.75
3 Metsulfuron methyl (active content) 1.00
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Fatty -oil ethoxylate 1.500
b) Alkyl phenol ethoxylate 16.000
6. Stabilizer (Epoxydised fatty oil) 4.000
7. Inert ingredient(s)
a) modified silicone di-oxide 8.000
b) Colloidal silica 46.75
Total 100.000 gm
Example - 3

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790
2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948
3 Metsulfuron methyl purity 95% (base 1.0%) 1.053
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Castor -oil ethoxylate -40 mole 1.500
b) Ethoxylated alkyl phenol 16.000
6. Stabilizer (Epoxydised soya bean oil) 4.000
7. Inert ingredient(s)
a) hydrophobic silica powder 8.000
b) colloidal silica 45.709
Total 100.000 gm
Example -4

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl purity 95%) (base 15.0%) 15.790
2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948
3 Metsulfuron methyl purity 95% (base 1.0%) 1.053
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Castor -oil ethoxylate -40 mole 1.500
b) Ethoxylated alkyl phenol 16.000
6. Stabilizer (Epoxydised soya bean oil) 4.000
7. Inert ingredient(s)
a) Polyvinyl pyrrolidone 5.000
b) colloidal silica 48.709

Example - 5

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790
2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948
3 Metsulfuron methyl purity 95% (base 1.0%) 1.053
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Castor -oil ethoxylate -40 mole 1.500
b) Ethoxylated alkyl phenol 16.000
6. Stabilizer (Epoxydised soya bean oil) 4.000
7. Inert ingredient(s)
a) Polyvinyl pyrrolidone 8.000
b) colloidal silica 45.709
Total 100.000 gm
Example -6

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl purity 95% (base 15.0%) 15.790
2 Cloquintocet mexyl purity 95 % (base 3.75%) 3.948
3 Metsulfuron methyl purity 95% (base 1.0%) 1.053
4 Dispersing agent (Sulphated poly aryl alkyl ethoxylate ammonium salt)) 4.000
5 Wetting/dispersing agent
a) Castor -oil ethoxylate -40 mole 1.500
b) Ethoxylated alkyl phenol 16.000
6. Stabilizer (Epoxydised soya bean oil) 4.000
7. Inert ingredient(s)
a) Polyvinyl pyrrolidone 10.000
b) colloidal silica 43.709
Total 100.000 gm
Example-7

s.No. Ingredient(s) Quantity (gm)
1 Clodinafop-propargyl purity 95% (base 10.0%) 10.526
2 Cloquintocet mexyl purity 94 % (base 2.50%) 2.660
3 Metsulfuron methyl purity 95% (base 2.0%) 2.105
4 Dispersing agent (Sulphated poly aryl alkyl 3.500

ethoxylate ammonium salt))
5 Wetting/dispersing agent
a) Castor -oil ethoxylate -40 mole 1.500
b) Ethoxylated alkyl phenol 22.000
6. Stabilizer (Epoxydised soya bean oil) 4.000
7. Inert ingredient(s)
a) modified silicone di-oxide 12.000
b) Colloidal silica 41.709
Total 100.000 gm
Field Trial
Field tests of the compositions according to the present invention were made at various controlled trial sites. The performance of the combination herbicide according to the present invention (Clodinafop 15 % and metsulfuron methyl 1%) was compared against the known compositions of Metsulfuron methyl 20% wettable powders and Clodinafop-propargyl 15% wettable powders, which were evaluated against weed flora in wheat crop during rabi season. The recommended package of practices for wheat crop was followed to raise the crop. The herbicide treatments were applied as post emergence spray at 35 days after sowing (DAS). The data on weed population (number/m2) and dry matter (gm/m2) was taken after 60 days after sowing and at the harvest. Similar yields (q/ha.) and yield attributed parameters like plant height, number of effective tiller, no. of grain per ear-head, test weight were recorded at harvest. A statistical analysis of the entire data was carried out. Phytotoxicity studies were also conducted on a rating scale of 0-10 for treatments of the compositions of the present invention @ 320 gm/acre (double the recommended dose) and Metsulfuron methyl @ 16 gm/acre (double the recommended dose).
The major weed flora recorded in the experimental field were grasses like Phalaris minor and Avena fatua and broad leaf weeds namely Chenopodium album, Rumex sp., Convolvulus arvensis, Melilotus alba, Medicago denticulata, Fumaria sp. Vicia sativa and Anagalis arvensis.
The trial surprisingly demonstrated that the compositions of the present invention at 160 gm/acre were the most effective and ideal treatment in controlling complex weed

flora in wheat. The superiority of the treatment is clearly depicted in the lowest weed population, dry weight of weeds and highest grain yield. The data clearly shows that metsulfuron methyl gave superior control of broad leaf weeds only.
Wherein the aforegoing reference has been made to components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described aspects and embodiments of the invention without departing from the principles taught herein. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims.

ABSTRACT
Disclosed are metsulfuron methyl active ingredient particles substantially homogenously coated with hydrophobic inert material. Also disclosed is a composition comprising a first active ingredient being clodinafop-propargyl and a second active ingredient being metsulfuron methyl, wherein said metsulfuron methyl is provided in a particulate form having a substantially homogenous coating of hydrophobic inert material provided thereon and processes for the preparation thereof.

A HERBICIDAL COMPOSITION COMPRISING CLODINAFOP-PROPARGYL AND METSULFURON-METHYL

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