FIELD OF THE INVENTION

The present invention relates to a novel herbicidal composition for protecting crops against weeds, undesired vegetation and grasses, and the corresponding methods of protection by application of the said composition. More, particularly, the present invention relates to herbicidal compositions comprising a chloroacetanilide particularly pretilachlor and a mixture of sulfonyl urea particularly metsulfuron methyl and chlorimuron ethyl.

BACKGROUND OF THE INVENTION

Weeds cause damage to agricultural crops and adversely affect crop productivity by competing with the crop for mineral nutrients, nitrogen, water and sunlight. Several herbicides and method of using such herbicides to control the weed species are known in the prior art. Each herbicide has its own weed control spectrum and may or may not control weeds outside its spectrum. Furthermore, the various known herbicides are not completely effective on their own towards the control of various weeds.

Chemical herbicides are typically categorized according to the time of application (e.g., pre-emergence or post-emergence herbicides). Pre-emergence herbicides are applied prior to germination of weed for control of germinating seeds without harming the desired plant species. Post emergence herbicides are effective against the weeds that have already emerged from the grounds and are applied on the leaves during growth of such weeds to have an herbicidal effect and leave little residual action in the soil.

The herbicidal effectiveness of a compound cannot be predicted from an examination of the substituent groups of the compound and often quite closely related compounds possess different weed control abilities. Various herbicides of the same class of compounds may have complementary areas of activity and thus can be useful to control a variety of weeds upon application of a combination. Furthermore, the various herbicides are not completely effective to control all the infesting weeds in a field crop, which necessitates the use of herbicidal combinations. An ideal herbicide should afford selective weed control, over the full growing season, with a single administration. It should be able to control all common weeds by controlling their growth and reproduction as the seed, the germinating seed, the seedling and the growing plant. It is often imperative to use herbicidal combinations to achieve these advantages, although the selection of the components of an ideal combination is not a straightforward choice for a skilled artisan.

It has now become a common practice to use herbicides of alternate modes of action in combination. When applied together or one after another, weed resistance has been found to decrease. The advantages of such a plan are that herbicide use rates have decreased considerably and, at the same time, the spectrum of weed control has increased. There are also less pollutants in the form of other harmful additives that used to regularly pollute the environment. The simultaneous or sequential application of two or more herbicides often result in an unfavourable interaction, such as altering the selectivity or decreasing the efficacy of the herbicide and in extreme circumstances total loss of crop. Herbicide interactions can be categorized as additive, synergistic or antagonistic. The interactions are said to be synergistic when the combined herbicides demonstrate an enhancement of their biological activity which is beyond the scope of their expected activity. An herbicidal combination is said to be antagonistic when the overall effect decreases the biological activity. In some cases, it may result in a toxic action.

These problems are further compounded by the widely differing sensitivities of crop plants against herbicidal chemicals. The repression of one weed species may also cause increased growth of another competing species, and that some weeds tend to become resistant against previously effective herbicides. Hence, there remains a need for a synergistic composition of herbicides which provides an effective control of weeds and broad-leaved grasses.

SUMMARY OF THE INVENTION

The present invention provides an herbicidal composition comprising a chloroacetanilide and a mixture of sulfonyl urea of in effective amounts and adjuvants.

In an embodiment, the herbicidal composition of the present invention comprises a chloroacetanilide pretilachlor and a mixture of sulfonyl urea of metsulfuron methyl and chlorimuron ethyl wherein pretilachlor is present in a range from 8% to 11% (w/w); metsulfuron methyl is present in a range from 0.02% to 0.2% (w/w); and chlorimuron ethyl is present in a range from 0.02% to 0.2% (w/w).

In an embodiment of the present invention, the adjuvants are selected from the group comprising dispersing agent, a wetting agent, a stabilizer, a carrier, a binder, a filler, a colorant and combinations thereof.

In an embodiment of the present invention, the dispersing agent is selected from the group comprising Sodium salt of methyl naphthalene sulfonate, sodium ligno sulphonate, acrylate copolymer, phenol sulfonic acid-formaldehyde- polycondensation as sodium salt, sodium polycarboxylate, sodium methyl oleoyl taurate and sodium lauryl sulphate or combination thereof, present in a range from 1% to 1.5% w/w.

In an embodiment of the present invention, the wetting agent is selected from the group comprising dialkyl naphthalene sulphonate sodium salt, alkylnaphthalene sulfonate (ANS) condensate blend, sodium ligno sulphonate, linear alcohol derivative and polyethylene glycol nonyl phenyl ether ammonium sulfate, present in a range from 1% to 1.5% w/w.

In an embodiment of the present invention, the stabilizer is selected from the group comprising silicic acid calcium salt (calcium silicate), magnesium silicate, ethanedioic acid, dihydrogen orthophosphate, citric acid, phosphoric acid, and combination thereof, present in a range from 1% to 4% w/w.

In an embodiment of the present invention, the carrier is selected from the group comprising silicon dioxide (40-63 pm particle size), aluminosilicate, and combination thereof, present in an amount of 2% to 7% w/w.

In an embodiment of the present invention, the binder is selected from the group comprising polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG 200), pine oil and starch present in an amount of 0.5% w/w.

In an embodiment of the present invention, the filler is selected from the group comprising corn starch, lactose monohydrate, quartz, talc, kaolin, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, kieselguhr, chalk, zeolite, calcite, sericite, acid clay, diatomaceous earth, natural rock, Fuller’s earth, meerschaum, gibbsite, dolomite or pumice; synthetic minerals such as precipitated silica, fumed silica, sodium silicate, silicon dioxide (0.5-10 pm particle size), alumina, aluminium silicate, and aluminium hydroxide, present in an amount of 74% to 79% w/w.

In an embodiment of the present invention, the colorant is selected from the group comprising naphthol, ponceau 4R, acid red dye and allura red AC present in an amount of 0.5% w/w.

In an embodiment of the present invention, the composition is formulated as granule.

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.

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.

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.

The term herbicide, as used herein, means an active ingredient that kills, controls or otherwise adversely modifies the growth of plants. Herbicidally effective or vegetation controlling amount is an amount of one or more active ingredient which causes an adversely modifying effect and includes deviations from natural development, killing, regulation, desiccation, retardation and the like. The terms plants, weeds and vegetation include germinant seeds, emerging seedlings, plants emerging from vegetative propagules and established vegetation. The term “active ingredient” (a.i.) or “active agent” used herein refers to that component of the composition responsible for control of weeds or undesired plants and vegetation.

As used herein, the term “adjuvants(s)” refers to inert substances which are commonly used as diluent, to provide stability or to increase the activity profile of the composition or formulation with or without having agrochemical activity or direct effect on the undesired weeds.

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.

In one aspect, the present invention provides an herbicidal combination comprising a first herbicide in combination with at least two sulfonylurea herbicides. In one aspect, the present invention may provide a combination comprising a first herbicide and a mixture of metsulfuron and its derivatives and chlorimuron and its derivatives.

In another aspect, the present invention provides a method for controlling undesirable vegetation in crops, which comprises applying a combination as defined herein to a locus of planted crops where undesirable vegetation occurs or might occur or to a locus where crops will be planted before planting or emergence of the crop.

In another aspect, the present invention may provide a method of controlling weeds at a locus by treating the locus with a combination comprising a first herbicide, metsulfuron methyl and chlorimuron ethyl.

In yet another aspect, the present invention provides an herbicidal composition for selectively controlling the weeds and grass infestation at a locus, said composition comprising herbicidally effective amount of a combination comprising a first herbicide pretilachlor, metsulfuron methyl and chlorimuron ethyl.

In another aspect, the present invention provides a method of selectively controlling the weeds and grass infestation at a locus, said composition comprising herbicidally effective amount of a combination comprising pretilachlor, metsulfuron methyl and chlorimuron ethyl. Broad leaf weed being selected from chickweed, dandelion, florida betony, japenese clover, plantain, common vetch, Echinochloa Beauvois, Cyperus difformis, and sedges in rice and paddy fields etc.

Pretilachlor is 2-Chloro-2',6'-diethyl-N-(2-propoxyethyl)acetanilide and is a broad- spectrum and selective herbicide. It is a pre-emergency herbicide for transplanted rice. It is applied before emergency of weeds, within 0-4 days of transplanting. Pretilachlor controls almost all the weeds (annual grasses, sedges and broad-leaved weeds) in rice. It dissolves quickly and spreads fast after application. It is very safe to rice crop as compared to other recommended herbicides. It has no phytotoxic effect on any variety of rice when used as recommended. Pretilachlor is represented by the formula

Metsulfuron methyl and chlorimuron ethyl are candidates of the sulfonylureas chemical class. Chemically, metsulfuron methyl is methyl 2-(N-((4-methoxy-6- methyl-l,3,5-triazin-2-yl)carbamoyl)sulfamoyl)benzoate that inhibits the acetolactate synthase (ALS) in plants as described in US4394506 (A) and has the following structure:

Its herbicidal activity is exemplified in The Pesticide Manual, Fifteenth Edition, 2009. Metsulfuron-methyl is used to control grass and broadleaf weeds in wheat, barley, rice, oats and triticale.

Chlorimuron ethyl is ethyl 2-(N-((4-chloro-6-methoxypyrimidin-2- yl)carbamoyl)sulfamoyl)benzoate that inhibits the acetolactate synthase (ALS) in plants as described in US4547215 (A) and has the following structure:

Chlorimuron ethyl can be used, for post-emergence control of important broadleaf weeds, such as cocklebur, pigweed, sunflower, annual morning glory and other broadleaf weeds in rice, soybeans and peanuts in post-emergence conditions. Its herbicidal activity is described in The Pesticide Manual, Fifteenth Edition, 2009.

Accordingly, the inventors of the present invention have formulated a synergistic herbicidal composition, comprising: pretilachlor, metsulfuron methyl and chlorimuron ethyl; and adjuvants; wherein pretilachlor is present in a range from 8% to 11% (w/w), metsulfuron methyl is present in a range from 0.02% to 0.2% (w/w), chlorimuron ethyl is present in a range from 0.02% to 0.2% (w/w).

The synergistic herbicidal composition of the present invention may be formulated as Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro -emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) 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 Granule (GR).

Preferably, the synergistic herbicidal composition is in the form of granule (GR) and the additives are selected from the group comprising a dispersing agent, a wetting agent, a stabilizer, a carrier, a binder, a filler, a colorant and combinations thereof.

It is generally observed that solid particles in a liquid undergo spontaneous aggregation to form lumps. Hence it is recommended to add a dispersant or a dispersing agent which prevents aggregation of solid particles and keeps them suspended in the fluid. Accordingly, the composition of the present invention preferably contains a dispersing agent such as such as amine salt of phosphate tristyryl phenol ethoxylated, acrylic copolymer, naphthalene sulphonate of formaldehyde condensate, lignin based sulphonate. One or more dispersing agents may be used in the synergistic composition of the present invention. The dispersing agent suitable for use in the present invention are Sodium salt of methyl naphthalene sulfonate, sodium ligno sulphonate, acrylate copolymer, phenol sulfonic acid- formaldehyde -polycondensation as sodium salt, sodium polycarboxylate, sodium methyl oleoyl taurate and sodium lauryl sulphate or combination thereof. Dispersing agent is present in a range from 1% to 1.5% (w/w) in the compositions of the present invention.

Wetting is the first stage of dispersion, in which the air surrounding the granular composition is substituted with water. Wetting of the herbicidal 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 herbicidal composition to facilitate the process of dispersion of the granules in the liquid. Accordingly, the composition of the present invention preferably contains a wetting agent such as naphthalene alkyl aryl sulphonate, dioctyl sulfosuccinate, sodium lauryl sulfate, non-ionic ethoxylated polyarylphenol phosphate ester, sodium alkyl naphthalene sulfonate or a combination thereof. Preferably, the wetting agent suitable for use in the present invention are dialkyl naphthalene sulphonate sodium salt, alkylnaphthalene sulfonate (ANS) condensate blend, sodium ligno sulphonate, linear alcohol derivative and polyethylene glycol nonyl phenyl ether ammonium sulfate. Wetting agent is present in a range from 1% to 1.5% (w/w).

Stabilizers are used in agrochemical formulation to prevent the active agrochemicals from crystallizing. Stabilizer suitable for the present invention are silicic acid calcium salt (Calcium silicate), magnesium silicate, ethanedioic acid, dihydrogen orthophosphate, citric acid, phosphoric acid, and combination thereof. Stabilizers are present in a range from 1% to 4% (w/w). Carriers are primarily used for effective dispersal of agrochemicals. The carriers suitable for the purpose of the present invention are silicon dioxide (40-63 pm particle size), aluminosilicate, and combination thereof. The silicon dioxide preferably has particle size from 40-63 pm. The carriers are present in a range from 2% to 7% (w/w).

The binders due to their absorption properties and interaction with water are recommended for herbicide formulation. The binders suitable for the purpose of the present invention is poly vinyl pyrrolidine, polyethylene glycol (PEG 200), pine oil and starch. Binders are present in an amount of 0.5% (w/w).

A “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, but not limited to, natural minerals such as com starch, lactose monohydrate, quartz, talc, kaolin, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, kieselguhr, chalk, zeolite, calcite, sericite, acid clay, diatomaceous earth, natural rock, Fuller’s earth, meerschaum, gibbsite, dolomite or pumice; synthetic minerals such as precipitated silica, fumed silica, sodium silicate, silicon dioxide (0.5-10 pm particle size), alumina, aluminium silicate, aluminium 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 silicon dioxide (0.5-10 pm particle size). Filler is present in a range from 74% to 79% (w/w).

The colorant suitable for the purpose of the present invention are naphthol, ponceau 4R, acid red dye and allura red AC. The colorant is present in an amount of 0.5% (w/w).

The synergistic herbicidal composition of the present invention was found to be non-phytotoxic and has good stability, wettability, suspensibility and dispersibility.

Thus, the granular herbicide of the present invention can be used, for example, for planting in industrial parks, railways, roadside shoulders, slopes, orchards (e.g., grape orchards, citrus orchards), tea fields, forests, grounds, and gardens. And the like to control undesired plants vegetating in the area.

The herbicides or combination of herbicides can be applied in different ways, for example, sequential application, tank-mix application and premix application. In sequential application, farmers use different herbicides, wherein the herbicide selection is often not based on the technical know-how. As a consequence, herbicides having the same mode of action contribute to resistance development. In tank-mix applications, farmers use different combinations of herbicides, most of the times without having the training to properly mix appropriate products. Homemade tank mixes may therefore not be as stable as a premix. In such cases, the tank-mix application usually results in non-judicious use of individual herbicides and end up with poor weed control. Moreover, the tank mixture is less convenient and potentially hazardous to people who are not trained to properly mix the products.

The present invention is more particularly described in the following examples that are intented as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to those of skill in the art. Unless otherwise noted, all parts, percentages, and ratios reported in the following examples are on a weight basis and all reagent used in the example were obtained or are available from the chemical suppliers.

Examples:

Example 1: Preparation of composition of Pretilachlor, Chlorimuron ethyl, Metsulfuron methyl in granule form.

Step 1:

Weighing the river sand in a reactor and start the instrument.

Weighing the stabilizer and carrier in a vessel and adding the Pretilachlor technical slowly over a period of 30 min. Weighing and adding the Chlonmuron ethyl followed by Metsulfuron methyl over a period of 15 min each.

Weighing all the raw materials according to the batch size in the following order

■ dispersing agent

■ wetting agent

■ binder

■ colorant

■ carrier

■ stabilizer

Pre-mixing the sample in a ribbon blender for Ihr.

Step 2: Grinding the sample through air jet milling instrument, Inlet pressure - 2 kg/cm ² and Grinding pressure - 6. 6.5 kg/ cm ²

Step 3: Preparation of polyvinyl pyrrolidone (PVP) solution (weighing 12 % water and heating at 50 degrees followed by addition of PVP to make clear solution.

Step 4: Spraying the polyvinyl pyrrolidone (PVP) solution on river sand and adding vice versa milled powder under rotation under heating 35 °C over a period of 40 min.

Step 5: Collecting the sample and dry in oven at 50 °C for 15 min.

Step 6: Submitting the sample for analysis.

Step 7: Packing the sample in suitable packaging.

Example 2: Compositions of the present invention The illustrative embodiments show the composition of Pretilachlor, Chlorimuron ethyl, Metsulfuron methyl in granule form in different amount as follows:

Table 1: Pretilachlor 8 % + Chlorimuron ethyl 0.02% + Metsulfuron methyl

0.02% (GR) Table 2: Pretilachlor 8.5% + Chlorimuron ethyl 0.06% + Metsulfuron methyl 0.06% (GR)

Table 3: Pretilachlor 9% + Chlorimuron ethyl 0.08% + Metsulfuron methyl

0.08% (GR)

Table 4: Pretilachlor 10% + Chlorimuron ethyl 0.1% + Metsulfuron methyl

0.1% (GR)

Table 5: Example 5: Pretilachlor 11% + Chlorimuron ethyl 0.2% +

Metsulfuron methyl 0.2% (GR) Example 3: Efficacy study for combination of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR)

FIELD AND SYNERGY STUDIES

Weeds were reported to reduce rice yields by 12 to 98%, depending on type method of rice establishment. Rice yield losses due to uncontrolled weed growth and weed competition were least (12%) in transplanted rice and highest in aerobic direct- seeded rice. Traditionally, weed control in India has been largely dependent on manual weeding. However, increased labour scarcity and costs are encouraging farmers to adopt to use herbicides.

The field studies were conducted to compare the weed controlling activity of the combination of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR). The active ingredient: Metsulfuron Methyl & Chlorimuron ethyl are belonging to chemical family Sulfonylureas with ALS inhibitor (inhibition of acetolactate synthase) mode of action & Pretilachlor comes under chemical family Chloroacetamide with very long-chain fatty acid synthesis (VLCFA) inhibitors mode of action. The combination has the potential of controlling the cross- spectrum weeds (broad leaf weeds, grassy weeds, and sedges) in rice. All three molecules are safe to transplanted when applied in pre-emergence (0 - 3 days after transplanting) application timing. The weed control activity of the individual herbicides of the invention and their combinations were evaluated against different type of weeds such as Cyperus difformis, Cyperus iria, Echinochloa colona, Echinochloa crusgalli, Monochoria vaginalis, Ludwigia parviflora & Eclipta alba. 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. Application was done through the broadcasting of Sand & test chemical at 0-3 days after transplanting of rice. 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 entire plot.

Appropriate analysis of plant response to herbicide combination is critical in determining the type of activity observed. The most widely used model is one Gowing* derived and Colby** modified. Gowing described a mathematical formula for calculating the predicting response values for pesticide mixtures. He suggested the expected (E) percent inhibition of growth induced by pesticide A plus pesticide B and plus pesticide C is as follows, *(Jerry Flint et al, 1988) ***

Where,

A = observed efficacy of active ingredient A at the same concentration as used in the mixture.

B = observed efficacy of active ingredient B at the same concentration as used in the mixture.

C = observed efficacy of active ingredient C at the same concentration as used in the mixture. 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. Analysing 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 1: Table 1 demonstrates synergy on weeds using the combination of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR). The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target sedge weeds were Cyperus iria and Cyperus difformis and the results are recorded in the table 1 below.

GR - granules, and GAH - gram active per hectare The results in table 1 clearly demonstrates synergy between Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR) combination against weeds like, Cyperus iria and Cyperus difformis. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination against sedges. Table 2: Table 2 demonstrates synergy on weeds using the combination of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR). The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target grass weeds were Echinochloa colonum and Echinochloa crusgalli. The results are recorded in the table 2 below.

GR — granules, and GAH — gram active per hectare

The results in table 2 clearly demonstrates efficacy of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR) combination against weeds like Echinochloa colonum and Echinochloa crusgalli. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination against grasses.

Table 3: Table 3 demonstrates synergy on weeds using the combination of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR). The field trials were carried out in India at various locations. The percentage efficacy was calculated after 30 days of application. The target broad leaf weeds were Monochoria vaginalis, Ludwigia parviflora and Eclipta alba. The results are recorded in the table 3 below.

GR — granules, and GAH — gram active per hectare The results in table 3 clearly demonstrates efficacy of Pretilachlor 8% + Chlorimuron ethyl 0.02% + Metsulfuron methyl 0.02% (GR) combination against weeds like, Monochoria vaginalis, Ludwigia parviflora and Eclipta alba. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination against broad leaf weeds. Although the present invention has been described and illustrated with respect to preferred embodiments and a preferred use thereof, it is not to be so limited since modifications and changes can be made therein which are within the full scope of the invention.