The present invention relates to synergistic herbicidal composition. More, particularly, the present invention relates to a synergistic herbicidal composition comprising mesotrione, atrazine and 2, 4-D. The present invention also relates to a process of preparing synergistic herbicidal composition.
BACKGROUND OF THE INVENTION
The control of undesired vegetation is extremely important in order to achieve high crop efficiency. Herbicides have a phytotoxic effect on unwanted plants and so they are used in plant protection for controlling weeds or totally inhibiting their growth. Herbicides can be non-selective, which means that they can destroy all growth. Such herbicides are used to clear waste ground, industrial sites, railways and railway embankments etc. are non-selective and kill all plant material with which they come into contact. Other types of herbicides are selective herbicides which kill specific target plants while leaving the desired/economically important plants relatively unharmed, some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant hormones. However, these herbicides may not be effective against certain type of other weeds which may also be present in the crop to be protected.
Therefore, there is a strong need for mixing two or more herbicides. Unfortunately, most of such herbicides exhibit phytotoxicity to the economically important plants as well as to the target plants called weeds which are sought to be controlled. Phytotoxic means harmful impact on plant caused due to application of any chemical/pesticide. The units used to measure the harmful impact of chemical/pesticide are called phytotoxicity. More the phytotoxicity more the damage caused to the plants. Phytotoxic effects caused by herbicides can be from spray droplets, soil residues or vapours contacting sensitive plants. Phytotoxic

effects are measured by different means in plants like epinasty, hyponasty, necrosis, vein clearing, wilting etc. Sometimes the damage appears as leaf cupping, crinkling and speckling, distorted leaves, fruit, flowers or stems, change in colour of leaves from light yellow to dark brown. Damage symptoms vary with the herbicide and the type of crop that has been affected and significantly affect the growth and yield of the crop.
Mixtures of selected herbicides have several advantages over the use of a single herbicide including (a) an increase in the spectrum of weeds controlled or an extension of weed control over a longer period of time; (b) an improvement in crop safety by using minimum doses of selected herbicides applied in combination rather than a single high dose of one herbicide; and (c) a delay in the appearance of resistant weed species to selected herbicides (Damalas C.A., Herbicide tank mixtures: common interactions, International Journal of Agriculture and Biology, Vol. 6, No. 1, 2004, pp. 209-212).
However, the activity and selective behaviour of a mixture is difficult to predict since the behaviour of each single herbicide in the mixture is often affected by the presence of the other(s) and the activity of the mixture may also vary considerably depending on chemical character, plant species, growth stage, and environmental conditions, which may result in reduced activity of the herbicides in the mixture.
In some cases, herbicidal active ingredients have been shown to be more effective in combination than when applied individually and this is referred to as "synergism." As described in the Herbicide Handbook of the Weed Science Society of America, Eighth Edition, 2002, p. 462 "'synergism' [is] an interaction of two or more factors such that the effect when combined is greater than the predicted effect based on the response to each factor applied separately". Applying combinations of two or more herbicides simultaneously to a field may be necessary or desired for such synergistic effects other than an increased control spectrum. For example, some herbicides have prolonged visual symptomology i.e. it takes a relatively long period of time (i.e., up to two weeks or more) for susceptible plants to show the visual effects of treatment. Generally, such

extended periods without any visual indication of herbicidal effectiveness detract from the commercial value of herbicidal product. Therefore, it is considered to be beneficial to combine two or more herbicides in a tank mix or a package-mix that will provide for more rapid bum down and earlier visual symptomology, thus improving the value of the overall herbicidal product.
Package-mix formulations have numerous challenges to the formulator of agricultural chemicals such as herbicides. For example, the formulation should contain the herbicidal active ingredients at as high as total concentration as possible, for maximum convenience to the end user and to minimize packaging and shipping costs, while keeping the active ingredients within the desired weight ratios with respect to each other. Most importantly, the package-mix formulation must exhibit sufficient physical and chemical stability to have an effective shelf life of at least a few months, preferably at least a year, and ideally at least two years.
Hence, there is a need in the art to provide synergistic herbicide compositions as they afford various advantages. Herbicide combinations offer advantages of improved weed control, a greater spectrum of weeds controlled, reduced cost and reduced residue problems. Hitherto, no attempts have been made to formulate a combination of Mesotrione, Atrazine and 2,4-D.
The combination of Mesotrione and Atrazine is known in various prior documents for effective weed control.
US Patent No. 5698493 provides a synergistic herbicidal composition comprising of Mesotrione and Atrazine.
US Patent No. 7071147 provides a process of controlling triazine-tolerant weeds by the application of a combination of mesotrione and a triazine herbicide (atrazine) to the locus of said weeds.
US Patent Publication No. 2011263425 provides method for controlling or modifying the growth of large crabgrass or white clover, comprising applying to

the locus of the large crabgrass or white clover, a herbici dally effective amount of a composition comprising a mixture of mesotrione and atrazine.
There is no mention in the prior art that combining 2,4-D with combination of Mesotrione and Atrazine produces a pronounced effect and improved performance in field.
Surprisingly, the inventors of the present invention have found that the herbicidal activity of Mesotrione and Atrazine combination can be significantly enhanced when combined with 2,4-D.
Therefore, there is a long felt need in the art to provide a stable formulation comprising Mesotrione, Atrazine and 2,4-D. In accordance with another aspect, the present invention provides a synergistic formulation containing the aforementioned synergistic composition and at least one excipient. Furthermore, the formulation is in a dosage form selected from the group consisting of dry flowable, water dispersible granules and liquid formulations.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a synergistic herbicidal composition comprising a) mesotrione, b) atrazine, c) 2,4-D and d) excipients.
In an embodiment the composition of the present invention comprises 2,4-D in the
form of acid, salt and ester. In another embodiment, 2,4-D is selected from the
group comprising 2,4-D-ammonium, 2,4-D-butotyl, 2,4-D-2-butoxypropyl, 2,4-D-
3-butoxypropyl, 2,4-D-butyl, 2,4-D-choline, 2,4-D-diethylammonium, 2,4-D-
dimethylammonium, 2,4-D-diolamine, 2,4-D-dodecylammonium, 2,4-D-ethyl,
2,4-D-2-ethylhexyl, 2,4-D-heptylammonium, 2,4-D-isobutyl, 2,4-D-isoctyl, 2,4-
D-isopropyl, 2,4-D-isopropylammonium, 2,4-D-sodium, 2,4-D-lithium, 2,4-D-
meptyl, 2,4-D-methyl, 2,4-D-octyl, 2,4-D-pentyl, 2,4-D-propyl, 2,4-D-tefuryl,
2,4-D-tetradecylammonium, 2,4-D-triisopropanolammonium, 2,4-D-
triethylammonium, and 2,4-D-tris(2-hydroxypropyl)ammonium, 2,4-D-trolamine, clacyfos.

In yet another embodiment, mesotrione, atrazine and 2,4-D are present in a weight ratio in the range from about 0.1 to 4 : 5 to 25 : 15 to 40.
In one another embodiment, mesotrione is present in an amount in the range from about 0.1 to 4% w/w, atrazine is present in an amount in the range from about 5 to 25% w/w and 2,4-D is present in an amount in the range from about 15 to 40%
w/w.
In an embodiment the composition of the present invention comprises excipient selected from the group comprising dispersing agent, wetting agent, anti-freezing agent, defoamer, stabilizer, biocide, disintegration agent, thickener and filler.
In another embodiment, the composition is 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) or A mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW), preferably as suspension concentrate or water dispersible granules.
In one another embodiment, the excipient is selected from the group comprising dispersing agent, wetting agent, anti-freezing agent, defoamer, stabilizer, biocide and thickener, and wherein the composition is formulated as suspension concentrate.

In another embodiment, the excipient is selected from the group comprising dispersing agent, wetting agent, disintegration agent, defoamer and filler, and wherein the composition is formulated as water dispersible granule.
In yet another embodiment, the dispersing agent is selected from the group comprising amine salt of phosphate tristyryl phenol ethoxylated, acrylic copolymer, naphthalene sulphonate of formaldehyde condensate, lignin based sulphonate and combinations thereof, and present in an amount in the range from
2tol0%w/w.
In one another embodiment, the wetting agent is selected from the group consisting of ethoxylated polyarylphenol phosphate ester, dioctyl sulphosuccinate, non-ionic ethoxylate, naphthalene alkyl aryl sulphonate and combinations thereof, and present in an amount in the range from 1 to 5% w/w.
In an embodiment, the anti-freezing agent is selected from the group consisting of propylene glycol, diethylene glycol, monoethylene glycol and combinations thereof, and present in an amount in the range from 2 to 10% w/w.
In another embodiment, the defoamer is dimethyl polysiloxane emulsion and present in an amount in the range from 0.01 to 1% w/w.
In yet another embodiment, the stabilizer is selected from the group consisting of sulphuric acid, hydrochloric acid, toluene sulfonic acid, phosphoric acid and combinations thereof, and present in an amount in the range from 0.5 to 2% w/w.
In one another embodiment, the biocide is selected from the group consisting of 20% aqueous dipropylene glycol solution of l,2-benzisothiazolin-3-one, formaldehyde and combinations thereof and present in an amount in the range from 0.01 to 0.50% w/w.
In an embodiment, the disintegration agent is selected from citric acid and sodium bicarbonate and present in an amount in the range from 0.5 to 2% w/w.
In another embodiment, the thickener is xanthan gum and present in an amount in the range from 0.01 to 0.50% w/w.

In yet another embodiment, the filler is selected from bentonite clay, china clay, silica, kaolin and diatomaceous earth.
In one another embodiment, pH of the synergistic herbicidal composition of the present invention is in the range from about 4 to about 7.
DETAILED DESCRIPTION OF THE INVENTION
Discussed below are some representative embodiments of the present invention. The invention in its broader aspects is not limited to the specific details and representative methods. The illustrative examples are described in this section in connection with the embodiments and methods provided. The invention according to its various aspects is particularly pointed out and distinctly claimed in the appended claims read in view of this specification and appropriate equivalents.
It is to be noted that, as used in the specification and the appended claims, 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 expression of various quantities in terms of "% w/w" or "%" means the percentage by weight, relative to the weight of the total solution or composition unless otherwise specified.
The term "active ingredient" (A.I.) or "active agent" used herein refers to that component of the composition responsible for control of pest/weed.
As used herein, the expressions "SL formulation", "SC formulation" "WDG or WG formulation" "GR formulation", "DF formulation", "CG formulation", "EC formulation", "EW formulation", "ME formulation", "WP formulation" are the international denominations adopted by the FAO (Food and Agricultural Organization of the United Nations) to designate "soluble liquid", "aqueous suspension concentrate", "water dispersible granules", "granular", "dry flowable",

"capsulated granules", "emulsion concentrate", "emulsion", "micro-emulsion" and "wettable powder" respectively.
In accordance with an embodiment of the invention, there is provided a synergistic herbicidal composition comprising mesotrione, atrazine and 2,4-D.
Mesotrione (IUPAC name: 2-(4-mesyl-2-nitrobenzoyl) cyclohexane-1,3-dione) belongs to the class of benzoylyclohexanedione/triketone herbicide and is represented by following structure:
0 0 N02

s v

Jt

.c
V^
\.

-:1:>

0

/'XCH3

Mesotrione works by inhibiting enzyme 4-hydroxyphenyl pyruvate dioxygenase (HPPD inhibitor). 2-(4-mesyl-2-nitrobenzoyl) cyclohexane-1, 3-dione is a selective herbicide for use in maize. The selectivity in maize is derived from differential metabolism (to the 4-hydroxy derivative) and also possibly from slower foliar uptake. 2-(4-mesyl-2-nitrobenzoyl) cyclohexane-1,3-dione is used for pre-emergence and post-emergence control of broad-leaved weeds such as Xanthium strumarium, Ambrosia triflda, Abutilon theophrasti, Chenopodium, Amaranthus, Polygonum spp. and some grass weeds in maize.
Atrazine (IUPAC name: 6-chloro-N2-ethyl-N4-isopropyl-l,3,5-triazine-2,4-diamine) belongs to the class of triazine herbicide. Atrazine is represented by following structure-

CI
AAA
N'
*N'
H

N'
H

Atrazine is a photosynthetic electron transport inhibitor at the photosystem II receptor site. Maize tolerance is attributed to rapid detoxification by glutathione transferases. Atrazine is a selective systemic herbicide, absorbed principally through the roots, but also through the foliage, with translocation acropetally in the xylem and accumulation in the apical meristems and leaves. Atrazine is used for pre- and post-emergence control of annual broad-leaved weeds and annual grasses in maize, sorghum, sugarcane, pineapples, chemical fallow, grassland, macadamia nuts, conifers and industrial weed control.
2,4-D (IUPAC name: 2,4-(dichlorophenoxy)acetic acid) belongs to the class of phenoxy herbicide. 2, 4-D is represented by following structure-
\ A i
T '0—CH,—C
CI OH
2,4-D works by mimicking the action of the plant growth hormone auxin, which results in uncontrolled growth and eventually death in susceptible plants. 2,4-D is a selective systemic herbicide. The salts are readily absorbed by the roots, whilst esters are readily absorbed by the foliage. Translocation occurs, with accumulation principally at the meristematic regions of roots and shoots. It acts as a growth inhibitor. 2,4-D is used for post-emergence control of annual and perennial broad-leaved weeds in cereals, maize, sorghum, grassland, established turf, grass seed crops, orchards (pome fruit and stone fruit), cranberries, asparagus, sugar cane, rice, forestry, and on non-crop land (including areas adjacent to water for control of broad-leaved aquatic weeds). The isopropyl ester can also be used as a plant growth regulator to prevent premature fruit fall in citrus fruit.
The invention encompasses within its scope all known acid, salt and ester forms of 2,4-D. Non-limiting examples include 2,4-D acid, 2,4-D-ammonium, 2,4-D-butotyl, 2,4-D-2-butoxypropyl, 2,4-D-3-butoxypropyl, 2,4-D-butyl, 2,4-D-

choline, 2,4-D-diethylammonium, 2,4-D-dimethylammonium, 2,4-D-diolamine,
2,4-D-dodecylammonium, 2,4-D-ethyl, 2,4-D-2-ethylhexyl, 2,4-D-
heptylammonium, 2,4-D-isobutyl, 2,4-D-isoctyl, 2,4-D-isopropyl, 2,4-D-
isopropylammonium, 2,4-D-sodium, 2,4-D-lithium, 2,4-D-meptyl, 2,4-D-methyl,
2,4-D-octyl, 2,4-D-pentyl, 2,4-D-propyl, 2,4-D-tefuryl, 2,4-D-
tetradecylammonium, 2,4-D-triisopropanolammonium, 2,4-D-triethylammonium, 2,4-D-tris(2-hydroxypropyl)ammonium, 2,4-D-trolamine, clacyfos.
In an embodiment the synergistic herbicidal composition comprises mesotrione, atrazine and 2, 4-D in a weight ratio in the range from about 0.1 to 4:5 to 25:15 to
40.
In another embodiment, mesotrione is present in an amount in the range from about 0.1 to 4% w/w, atrazine is present in an amount in the range from about 5 to 25% w/w, and 2,4-D is present in an amount in the range from about 15 to 40%
w/w.
The synergistic herbicidal composition comprises excipient selected from the group comprising dispersing agent, wetting agent, anti-freezing agent, defoamer, biocide, disintegrating agent, stabilizer, thickener and filler.
The synergistic 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). The abbreviations provided for various formulations are the international denominations adopted by the FAO (Food and Agricultural Organization of the United Nations).
Preferably, the composition of the present invention is formulated as suspension concentrate and water dispersible granule.
In an embodiment, the excipient is selected from the group comprising dispersing agent, wetting agent, anti-freezing agent, defoamer, biocide, stabilizer, thickener, and the composition is in the form of a suspension concentrate (SC). The term "suspension concentrate" used herein refers to a suspension of the active herbicide and excipients in a small quantity of liquid, usually water.
In another embodiment, the excipient is selected from the group comprising dispersing agent, wetting agent, disintegration agent, defoamer, filler, and wherein the formulation is water dispersible granule. The term "water dispersible granules" used herein refers to granules that are obtained by blending and agglomerating a ground solid active ingredient together with excipients.
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 keep them suspended in fluid. Accordingly, the composition of the present invention contains dispersing agents 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 is present in an amount in the range from 2tol0%w/w.
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. Non-limiting examples of wetting agents that can be used in the present invention include ethoxylated polyarylphenol phosphate ester, dioctyl sulphosuccinate, non-ionic ethoxylate, naphthalene alkyl aryl sulphonate. The alkyl aryl sulphonates are the one in which the alkyl group contains approximately 1 to 5 carbon atoms and in which the aryl nucleus is selected from the group consisting of benzene and naphthalene. One or more wetting agents may be used in the synergistic composition of the present invention. The wetting agent is present in an amount in the range from 1 to 5% w/w.
An anti-freezing agent is generally added to the composition, to prevent the aqueous compositions from freezing. Suitable anti-freezing agents useful herein, but not limited to, include propylene glycol, diethylene glycol, monoethylene glycol and combinations thereof. Preferably, the anti-freezing agent is present in an amount in the range from 2 to 10% w/w.
A defoamer, also called as anti-foaming agent, is generally added to the composition as foam formation prevents the efficient filling of a container. Preferably, the defoamer is polydimethyl siloxane emulsion. In the herbicidal composition of the present invention the defoamer is present in an amount in the range from 0.01 to 1% w/w.
In an embodiment, the pH of the herbicidal composition of the present invention is from about 3 to about 7, more preferably from about 4 to 6. Accordingly, the herbicidal composition of the present invention may further comprise a stabilizer. The stabilizer provides chemical stability to mesotrione in the composition. The skilled person is well aware of the suitable stabilizers, for example, hydrochloric acid, sulphuric acid and toluene sulfonic acid. However, it is preferred that the pH adjuster is phosphoric acid. The stabilizer is present in an amount in the range from 0.5 to 2% w/w.
The disintegration agent is selected from citric acid and sodium bicarbonate and present in an amount in the range from 0.5 to 2% w/w.

The synergistic herbicidal composition comprises a biocide selected from the group consisting of 20% aqueous dipropylene glycol solution of 1,2-benzisothiazolin-3-one, formaldehyde and combinations thereof, and present in an amount in the range from 0.01 to 0.50% w/w. The biocide is added to the composition of the present invention for its preservation against spoilage from bacteria, yeasts and fungi.
It is necessary to add a thickener to the composition to reduce the tendency of the composition to disperse when sprayed, and decrease the likelihood of it being rinsed off from the crops. Preferably, the synergistic herbicidal composition comprises xanthan gum as thickener in an amount in the range from 0.10 to 0.50%
w/w.
Filler is added to the composition to improve the handling and storage characteristics of the composition. Fillers also add mass and/or volume to the active ingredient in order to facilitate precise measurement of the doses. Suitable fillers that may be used in the composition of the present invention include, but not limited to, bentonite clay, china clay, silica, kaolin and diatomaceous earth.
Useful plants on which the composition of the present invention can be used include crops such as maize, sugar cane and oil seeds. The composition of the present invention can be used to control unwanted vegetation including grasses, sedges such as Cyperus spp. and weeds. The weeds include broad-leaved weeds such as Xanthium strumarium, Ambrosia triflda, Abutilon theophrasti, Chenopodium, Amaranthus, Polygonum spp. etc.
The present invention also relates to a process of preparation of synergistic herbicidal composition comprising mesotrione, atrazine, 2,4-D and excipients.
The composition of the present invention is relatively safer to human beings, animals and abiotic factors. The present invention provides an improved stable and ready to use herbicidal composition of mesotrione, atrazine and 2,4-D which overcomes the problems faced by the farmers in the field of physically mixing the individual, commercially available formulations at the desired field.

The synergism manifested by the composition of the present invention comprising mesotrione atrazine and 2,4-D allows a substantial reduction in the application rates of each of these active ingredients, while maintaining good herbicidal efficacy. Decreasing application rates reduces treatment cost to the farmer and also eases the burden on the environment both from manufacturing waste and crop protection chemical residues.
It has been surprisingly found that the synergistic herbicidal composition of the present invention provides a wide spectrum control of weeds, delaying the appearance of the resistant strains of weeds.
In another aspect the present invention provides a method for controlling weeds, comprising contacting crops or their environment with an effective amount of the composition of the present invention.
The embodiments of the present invention are more particularly described in the following examples that are intended 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 reagents used in the examples were obtained or are available from the chemical suppliers.
EXAMPLES
Examples 1-3
The synergistic herbicidal composition of the present invention comprising mesotrione, atrazine and 2,4-D in the form of suspension concentrate are provided in Examples 1-3 (Table 1). The unit of each component of the composition are expressed in "% w/w" i.e. the percentage by weight, relative to the weight of the total solution or composition.
The excipients used in Examples 1-3 for preparing the synergistic composition of the present invention in suspension concentrate form are dispersing agent, wetting agent, anti-freezing agent, stabilizer, defoamer, biocide and thickener.

Examples 1-3:
Table 1: Synergistic herbicidal composition formulated as suspension concentrate (SC)

S.No. Component Function Example 1 Example 2 Example 3
1 Mesotrione Active ingredient 1.2 1.5 1.8
2 Atrazine Active ingredient 12 14 16
3 2,4-D Acid Active ingredient 25 25 25
4 Propylene glycol Anti-freezing agent 02-10
5 Acrylic copolymer Dispersing agent 02-10
6 Non-ionic ethoxylate Wetting agent 01-05
7 Phosphoric acid Stabilizer 00.50-02.00
8 Dimethyl Polysiloxane emulsion Defoamer 00.01-00.50
9 20% aqueous dipropylene glycol solution of 1,2-benzisothiazolin-3-one Biocide 00.01-00.50
10 Xanthan Gum Thickener 00.01-00.50
11 Demineralised water Solvent Q.S.
QS: quantity sufficient required to make 100% w/w formulation

Table 2 provides quantities of active ingredients and raw material charged to prepare the synergistic composition of the present invention in SC form. The active ingredients such as mesotrione, atrazine and 2,4-D acid are in technical grade. The entries for active ingredients, mesotrione, atrazine and 2,4-D acid in table 2 varies from that of table 1, as the entries in table 1 are for 100% pure compounds whereas the entries in Table 2 are for technical ones with certain percentage of impurities. The examples 1, 2, 3 of Table 1 corresponds to examples 4, 5, 6 of table 2. Hence, example 1 of table 1 for mesotrione 1.2% w/w, atrazine 12% w/w and 2,4-D acid 25% of 100% purity corresponds to example 4 of table 2 for mesotrione 1.23 kg, atrazine 12.38 kg and 2,4-D acid 25.52 kg of 98%, 97% and 98% purity respectively.
Table 2: Quantities of active ingredients and raw material charged

Sr. No. Components Weight (kg)

Example 4 Example 5 Example 6
1 Mesotrione technical (basis of 98%) 1.23 1.54 1.84
2 Atrazine technical (basis of 97%) 12.38 14.44 16.50
3 2,4-D Acid technical (basis of 98%) 25.52 25.52 25.52
4 Propylene glycol 05.00 05.00 05.00
5 Acrylic copolymer 05.00 05.00 05.00
6 Non-ionic ethoxylate 02.00 02.00 02.00

7 Phosphoric acid 00.20 00.20 00.20
8 Dimethyl Polysiloxane emulsion 00.10 00.10 00.10
9 20% aqueous dipropylene glycol solution of 1,2-benzisothiazolin-3-one 00.10 00.10 00.10
10 Xanthan gum 00.10 00.10 00.10
11 Demineralised water 48.37 46.00 43.64
Example 7: Process of preparing synergistic herbicidal composition in suspension concentrate form
All the components were weighed as per example 5. The acrylic copolymer (5 kg) and non-ionic ethoxylate (2 kg) were diluted in de-mineralised water (46 kg) and solubilized by high shear mixing. Then propylene glycol (5 kg), mesotrione (1.54 kg), atrazine (14.44 kg), 2,4-D (25.52 kg), phosphoric acid (0.2kg), dimethyl polysiloxane emulsion (0.10 kg), 20% aqueous dipropylene glycol solution of 1,2-benzisothiazolin-3-one (0.10 kg) were added and mixed to obtain a homogeneous mass. The homogeneous mass was grinded in bead mill. The grinding was carried out until a mean particle size of 3-5(D-90) microns was obtained. After grinding, 2% water solution of xanthan gum was added under low stirring to obtain the synergistic herbicidal composition.
Table 3: Synergistic herbicidal composition formulated as water dispersible granules (WG)

S.No. Component Function Example 8 Example 9 Example 10
1 Mesotrione Active ingredient 1.2 1.6 2.0
2 Atrazine Active ingredient 20 17 14

3 2,4-D Acid Active ingredient 24 28 32
4 Naphthalene sulphonate derivative/ Acrylic graft polymer Dispersing agent 2-10
5 Naphthalene alkyl aryl sulphonate Wetting agent 1-5
6 Dimethyl polysiloxane emulsion Defoamer 0.1-1
7 Citric acid Disintegratin g agent 0.5-2
8 China clay Filler Q.S.
QS: quantity sufficient required to make 100% w/w formulation
Table 4 provides quantities of active ingredients and raw material charged to prepare the synergistic composition of the present invention in WG form. The active ingredients such as mesotrione, atrazine and 2,4-D acid are in technical grade. The entries for active ingredients, mesotrione, atrazine and 2,4-D acid in table 4 varies from that of table 3, as the entries in table 3 are for 100% pure compounds whereas the entries in Table 4 are for technical ones with certain percentage of impurities. The examples 8, 9, 10 of Table 1 corresponds to examples 11, 12, 13 of table 4.
Table 4: Quantities of active ingredients and raw material charged

Sr. No. Components Weight (kg)

Example 11 Example 12 Example 13
1 Mesotrione technical (basis of 98%) 1.23 1.64 2.05

2 Atrazine technical (basis of 97%) 20.62 17.53 14.44
3 2,4-D Acid technical (basis of 98%) 24.49 28.58 32.66
4 Naphthalene sulphonate derivative 4.00 4.00 4.00
5 Naphthalene alkyl aryl sulphonate 2.00 2.00 2.00
6 Acrylic graft copolymer 2.00 2.00 2.00
7 Dimethyl polysiloxane emulsion 0.10 0.10 0.10
8 Citric acid 1.00 1.00 1.00
9 China clay 44.56 43.15 41.75
Example 14: Process of preparing synergistic herbicidal composition in WG form
All the components were weighed as per example 11 and mixed well using proper ribbon blender type mixer to obtain a mixture. The mixture was milled with suitable air jet/ACM mill. The milling chamber was kept at 6 kg per cm2 and at feeding pressure of 2 kg per cm2. The mixture was milled to achieve a particle size below 10 microns and then mixed properly in a post blender. A dough was prepared using the milled mixture and 10% to 20% water in suitable dough-mixer. The dough was then extruded using proper extruder having suitable screen while maintaining the temperature of the screen below 45°C to obtain extruded granules. The extruded granules were dried using a fluid bed dryer. The air flow was kept at 75% and the temperature of the air was maintained at 47°C. The granules were dried till 3% moisture content remained in the granules.

Evaluation of bio-efficacv of the synergistic herbicidal composition against weed spectrum in sugarcane crop
Field trials were performed to evaluate the biological efficacy of the synergistic herbicidal composition of present invention and reference products against Cyperus spp. and other broad leaved weeds. Table 5 provides treatment details of herbicidal compositions for evaluation of bio-efficacy against Cyperus spp. and other broad leaved weeds in sugarcane crop. The evaluation was performed by comparing the synergistic herbicidal composition of the present invention (Mesotrione + Atrazine + 2,4-D in SC and WG forms) against the reference products, such as 2,4-D sodium salt technical (having 2,4-D acid 80%) and mesotrione 2.27% w/w + atrazine 22.7% w/w SC.
Table 5: Treatment details for evaluation of bio-efficacy of synergistic herbicidal composition

Particular Treatment A.I. (Percentage) Dose (A.I. g/acre) Dose
Tl Mesotrione +
Atrazine + 2,4-D
SC 1.5+ 14+25 78.75 + 735.28 + 1312.50 5250 ml/ha
T2 Mesotrione +
Atrazine + 2,4-D
SC 1.8+16+25 94.50 + 840 + 1312.50 5250 ml/ha
T3 Mesotrione +
Atrazine + 2,4-D
SC 1.2+12+25 63 + 630 + 1312.50 5250 ml/ha
T4 Mesotrione +
Atrazine + 2,4-D
WG 1.2+20+24 60 + 1000 + 1200 5000 g/ha
T5 Mesotrione + Atrazine + 2,4-D 1.6+17+28 80 + 850 + 1400 5000 g/ha

WG
T6 Mesotrione +
Atrazine + 2,4-D
WG 2+14+32 100 + 700 + 1600 5000 g/ha
T7 2,4-D sodium
salt technical
(having 2,4-D
acid 80%) 80 2600 3250 g/ha
T8 Mesotrione
2.27% w/w +
Atrazine 22.7%
w/w SC 2.27 + 22.7 79.45 + 794 3500 ml/ha
T9 Weed free - - -
T10 Control - - -
Method of observation
The experiment was laid out in Randomized Block Design (RBD) with three replications. The plot size was 5.0 x 5.0 m. All the recommended agronomic practices were followed throughout the cropping period. The various herbicidal compositions as per Table 5 were sprayed on sugarcane crop during first season at 3-5 leaf stage of weed flora. High volume (Knapsack) sprayer fitted with Flat Fan (WFN 20) nozzle was used for spraying. The spray volume used was 500 litres per hectare.
Observations Recorded
Weed Density
The weed population count (Cyperus spp. and broad leaved weeds separately) was recorded at 15, 30, 45, 60 and 75 days after application of different herbicide treatments. For recording the weed population, an area of 0.5 x 0.5 m (0.25 m2) was marked at three spots in each treatment and weed observations were made

from the same marked area and average was worked out and expressed in weed number per m2 area.
Weed Dry Weight
Weed dry weight of Cyperus spp. and broad leaved weeds in different herbicide treatments, were recorded a separate area of 0.5 x 0.5 m was marked in each plot and the weeds in each marked quadrant were removed at 15, 30, 45, 60 and 75 days after herbicide spray and oven dried at 80 for 12 hours and weighed to estimate the dry weight of weeds. The weed dry weight was expressed in terms of g/m2 area.
Weed Control Efficiency
Using the species-wise weed dry weight recorded at 15, 30, 45, 60 and 75 days after spray of herbicide under absolute control and the respective treatments, the weed control efficiency (WCE) for each treatment was worked out by using formula given below.
„ _. Weed dry weight in the untreated plot-Weed dry weight in the treated plot *nn
WCb (%) = — — —— ■ — X 100
Weed dry weight in the untreated plot
The final weed data (weed count and weed dry weight) was transformed using the formula (X+0.5)0'5 for analysis purpose.
Table 6: Weed density (count/m2) at different days after application of different herbicidal treatments on Sugarcane crop

Treatments Cyperus spp. Other broad leaved weeds

15 DAT 30 DAT 45 DAT 60 DAT 75 DAT 15 DAT 30 DAT 45 DAT 60 DAT 75 DAT
Tl 8.67 (3.03) 11.33 (3.44) 13.33 (3.72) 14.67 (3.89) 15.33 (3.98) 5.67 (2.48) 8.33 (2.97) 10.33 (3.29) 11.67 (3.49) 12.33 (3.58)
T2 8.00 (2.92) 10.67
(3.34) 12.00 (3.54) 12.67 (3.63) 13.67 (3.76) 5.00
(2.35) 7.67 (2.86) 9.00 (3.08) 9.67 (3.19) 10.67
(3.34)

T3 12.00 15.67 19.33 23.33 30.33 11.33 12.33 13.67 18.33 26.33

(3.54) (4.02) (4.45) (4.88) (5.55) (3.44) (3.58) (3.76) (4.34) (5.18)
T4 10.33 12.67 15.67 19.67 25.67 11.00 12.00 13.33 16.67 23.33

(3.29) (3.63) (4.02) (4.49) (5.12) (3.39) (3.54) (3.72) (4.14) (4.88)
T5 3.33 4.67 7.00 9.33 15.00 1.33 2.67 5.00 7.33 13.00

(1.96) (2.27) (2.74) (3.14) (3.94) (1.35) (1.78) (2.35) (2.80) (3.67)
T6 6.67 9.00 11.33 12.33 13.00 3.67 6.00 8.33 9.33 10.00

(2.68) (3.08) (3.44) (3.58) (3.67) (2.04) (2.55) (2.97) (3.14) (3.24)
T7 12.33 16.33 20.00 24.33 31.33 18.33 21.33 25.00 28.33 40.67

(3.58) (4.10) (4.53) (4.98) (3.64) (4.34) (4.67) (5.05) (5.37) (6.42)
T8 11.67 15.33 18.67 22.67 28.00 16.00 19.67 22.33 29.33 39.67

(3.49) (3.98) (4.38) (4.81) (5.34) (4.06) (4.49) (4.78) (5.46) (6.34)
T9 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

(0.71) (0.71) (0.71) (0.71) (0.71) (0.71) (0.71) (0.71) (0.71) (0.71)
25.67 36.33 44.33 58.33 78.67 30.67 36.67 41.00 56.33 74.33
T10
(5.12) (6.07) (6.70) (7.67) (8.90) (5.58) (6.10) (6.44) (7.54) (8.65)
SEm+ 0.521 0.734 0.889 1.183 1.62 0.717 0.825 0.904 1.227 1.661
CD5% 1.56 2.196 2.661 3.543 4.851 2.147 2.469 2.707 3.674 4.974
* Values in parenthesis are square root transformed; values in the bracket are original values; CD 5%= Critical difference
Table 7: Weed dry weight (g/m2) at different days after application of different herbicidal treatments on Sugarcane crop

Treatments Cyperus spp. Other broad leaved weeds

15 DAT 30 DAT 45 DAT 60 DAT 75 DAT 15 DAT 30 DAT 45 DAT 60 DAT 75 DAT
Tl 2.25 2.95 3.47 3.81 3.99 1.70 2.50 3.10 3.50 3.70

(1.66) (1.86) (1.99) (2.08) (2.12) (1.48) (1.73) (1.90) (2.00) (2.05)
T2 2.00 (1.58) 2.67 (1.78) 3.00 (1.87) 3.17 (1.92) 3.42 (1.98) 1.50 (1.41) 2.30 (1.67) 2.70 (1.79) 2.90 (1.84) 3.20 (1.92)
T3 3.96 (2.11) 5.17 (2.38) 6.38 (2.62) 7.70 (2.86) 10.01
(3.24) 3.74 (2.06) 4.07 (2.14) 4.51
(2.24) 6.05 (2.56) 8.69
(3.03)
T4 2.69 (1.78) 3.29 (1.95) 4.07 (2.14) 5.11
(2.37) 6.67 (2.68) 3.08 (1.89) 3.36 (1.96) 3.73 (2.06) 4.67
(2.27) 6.53 (2.65)
T5 0.60 (1.05) 0.84 (1.16) 1.26 (1.33) 1.68 (1.48) 2.70 (1.79) 0.31 (0.90) 0.61 (1.06) 1.15 (1.28) 1.69 (1.48) 2.99 (1.87)
T6 1.27 (1.33) 1.71 (1.49) 2.15 (1.63) 2.34 (1.69) 2.47 (1.72) 1.10
(1.27) 1.80 (1.52) 2.50 (1.73) 2.80 (1.82) 3.00 (1.87)
T7 4.07 (2.14) 5.39
(2.43) 6.60 (2.66) 8.03 (2.92) 10.34 (3.29) 6.05 (2.56) 7.04 (2.75) 8.25 (2.96) 9.35 (3.14) 13.42 (3.73)
T8 3.03 (1.88) 3.99 (2.12) 4.85 (2.31) 5.89
(2.53) 7.28 (2.79) 4.16 (2.16) 5.11
(2.37) 5.81 (2.51) 7.63 (2.85) 10.31 (3.29)
T9 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71) 0.00 (0.71)
T10 10.78 (3.36) 15.26 (3.97) 18.62
(4.37) 24.50 (5.00) 33.04 (5.79) 12.88 (3.66) 15.40 (3.99) 17.22 (4.21) 23.66 (4.92) 31.22 (5.63)
SEm+ 0.231 0.326 0.397 0.528 0.719 0.291 0.339 0.375 0.514 0.688
CD5% 0.692 0.977 1.19 1.582 2.153 0.872 1.016 1.122 1.538 2.059
* Values in parenthesis are square root transformed; values in the bracket are original
values; CD5% = Critical difference

Table 8: Weed control efficiency (%) at different days after application of different herbicidal treatments on Sugarcane crop

Trea
tmen
ts Cyperus spp. Other broad leaved weeds

15 DAT 30 DAT 45 DAT 60 DAT 75 DAT 15 DAT 30 DAT 45 DAT 60 DAT 75 DAT
Tl 79.09 80.69 81.39 84.43 87.94 86.79 83.77 82.00 85.20 88.15
T2 81.45 82.52 83.89 87.07 89.66 88.36 85.06 84.32 87.74 89.75
T3 63.27 66.11 65.74 68.57 69.71 70.97 73.58 73.80 74.43 72.17
T4 75.09 78.41 78.12 79.12 79.80 76.09 78.18 78.33 80.27 79.08
T5 94.44 94.49 93.23 93.14 91.83 97.63 96.01 93.32 92.87 90.42
T6 88.25 88.79 88.44 90.44 92.52 91.45 88.31 85.49 88.17 90.39
T7 62.26 64.68 64.55 67.23 68.71 53.04 54.30 52.09 60.48 57.01
T8 71.86 73.88 73.93 75.94 77.97 67.71 66.79 66.28 67.77 66.96
T9 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0 100.0 0
T10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Data presented in table 8 shows that weed control efficiency was significantly affected by all the treatments compared to control when observed at 15, 30, 45, 60 and 75 days after treatment (DAT). At 75 DAT the synergistic herbicide composition of the present invention, @ all the doses, recorded highest weed control efficiency closely followed by T8 i.e. mesotrione 2.27% w/w+ atrazine 22.7% w/w SC. Similar results were observed in case of weed density and weed dry weight.
The yield of sugarcane from individual plots were recorded and expressed in tons per hectare and presented in Table 9.

Table 9: Yield of sugarcane based on different herbicidal treatments

Treatments Yield (Tons/Hectare)
Tl 68.33
T2 70.04
T3 63.34
T4 67.11
T5 74.78
T6 72.23
T7 51.25
T8 65.24
T9 68.82
T10 47.54
SEm±_ 0.531
CD(p=0.05) 1.589
Tl 68.33
The highest yield of 77.78 tons ha"1 was observed in plots treated with T5. Overall, the yield was significantly higher when the plots were treated with the synergistic herbicidal composition of the present invention comprising mesotrione, atrazine and 2,4-D acid in SC and WG forms, as compared to the reference products viz. 2,4-D sodium salt technical (having 2,4-D acid 80%) and mesotrione 2.27% w/w + atrazine 22.7% w/w SC.
Phytotoxicity Observations
For phytotoxicity evaluation on sugarcane crop, following observations were made by observing temporary or long lasting damage to the leaves if any viz., leaf

injury on tips and leaf surface, wilting, vein clearing, necrosis, epinasty and hyponasty at 1, 3, 5, 7 and 10 days after application of the synergistic herbicidal composition of the present invention. Crop injury was observed on visual rating from 1-10 scale as given in table 10.
Table 10:

Rating Crop Injury (%) Verbal Description
0 - No symptoms
1 1-10 Very slight discoloration
2 11-20 More severe, but not lasting
3 21-30 Moderate and more lasting
4 31-40 Medium and lasting
5 41-50 Moderately heavy
6 51-60 Heavy
7 61-70 Very Heavy
8 71-80 Nearly destroyed
9 81-90 Destroyed
10 91-100 Completely destroyed
Table 11. Phytotoxic effect of synergistic composition of the present invention on sugarcane crop
Phytotoxicity rating
Treatments yejn
tip Wilting Necrosis Epinasty Hyponasty
Clearing injury

Tl 0 0 0 0 0 0
T2 0 0 0 0 0 0
T3 0 0 0 0 0 0
T4 0 0 0 0 0 0
T5 0 0 0 0 0 0
T6 0 0 0 0 0 0
The synergistic herbicidal composition of the present invention gave good control of weeds along with significant increase in yield and better economics to farmers as compared to the reference products. Further, the use of the synergistic herbicidal composition resulted in better crop condition, i.e. fresh green leaves and did not produce any phytotoxic symptoms on the plants.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitations with respect to the specific embodiments illustrated is intended or should be inferred. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.

We claim:

1.A synergistic herbicidal composition comprising:
a) mesotrione;
b) atrazine;
c) 2,4-D; and
d) excipients

2. The synergistic herbicidal composition as claimed in claim 1, wherein 2,4-D is in the form of acid, ester and salt.
3. The synergistic herbicidal composition as claimed in claim 2, wherein 2,4-D is selected from the group comprising 2,4-D-ammonium, 2,4-D-butotyl, 2,4-D-2-butoxypropyl, 2,4-D-3-butoxypropyl, 2,4-D-butyl, 2,4-D-choline, 2,4-D-diethylammonium, 2,4-D-dimethylammonium, 2,4-D-diolamine, 2,4-D-dodecylammonium, 2,4-D-ethyl, 2,4-D-2-ethylhexyl, 2,4-D-heptylammonium, 2,4-D-isobutyl, 2,4-D-isoctyl, 2,4-D-isopropyl, 2,4-D-isopropylammonium, 2,4-D-sodium, 2,4-D-lithium, 2,4-D-meptyl, 2,4-D-methyl, 2,4-D-octyl, 2,4-D-pentyl, 2,4-D-propyl, 2,4-D-tefuryl, 2,4-D-tetradecylammonium, 2,4-D-triisopropanolammonium, 2,4-D-triethylammonium, and 2,4-D-tris(2-hydroxypropyl)ammonium, 2,4-D-trolamine, clacyfos.
4. The synergistic herbicidal composition as claimed in claim 1, wherein mesotrione, atrazine and 2,4-D are present in a weight ratio in the range from about 0.1 to 4 : 5 to 25 : 15 to 40.
5. The synergistic herbicidal composition, as claimed in claim 1, wherein mesotrione is present in an amount in the range from about 0.1 to 4% w/w, atrazine is present in an amount in the range from about 5 to 25% w/w, 2,4-D is present in an amount in the range from about 15 to 40% w/w.
6. The synergistic herbicidal composition, as claimed in claim 1, wherein the excipient is selected from the group comprising dispersing agent, wetting

agent, anti-freezing agent, defoamer, stabilizer, biocide, disintegration agent, thickener and filler.
7. The synergistic herbicidal composition as claimed in claim 1, wherein the composition is 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) or A mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW).
8. The synergistic herbicidal composition as claimed in claim 1 to 7, wherein the composition is formulated as suspension concentrate or water dispersible granules.
9. The synergistic herbicidal composition, as claimed in claim 6 and 7, wherein the excipient is selected from the group comprising dispersing agent, wetting agent, anti-freezing agent, defoamer, stabilizer, biocide and thickener, and wherein the composition is formulated as suspension concentrate.
10. The synergistic herbicidal composition, as claimed in claim 6 and 7, wherein the excipient is selected from the group comprising dispersing agent, wetting agent, disintegration agent, defoamer and filler, and wherein the composition is formulated as water dispersible granule.

11. The synergistic herbicidal composition as claimed in claim 6, wherein the dispersing agent is selected from the group comprising amine salt of phosphate tristyryl phenol ethoxylated, acrylic copolymer, naphthalene sulphonate of formaldehyde condensate, lignin based sulphonate and combinations thereof, and present in an amount in the range from 2 to 10% w/w.
12. The synergistic herbicidal composition as claimed in claim 6, wherein the wetting agent is selected from the group consisting of ethoxylated polyarylphenol phosphate ester, dioctyl sulphosuccinate, non-ionic ethoxylate, naphthalene alkyl aryl sulphonate and combinations thereof, and present in an amount in the range from 1 to 5% w/w.
13. The synergistic herbicidal composition as claimed in claim 6, wherein the anti-freezing agent is selected from the group consisting of propylene glycol, diethylene glycol, monoethylene glycol and combinations thereof, and present in an amount in the range from 2 to 10% w/w.
14. The synergistic herbicidal composition as claimed in claim 6, wherein the defoamer is dimethyl polysiloxane emulsion and present in an amount in the range from 0.01 to 1% w/w.
15. The synergistic herbicidal composition as claimed in claim 6, wherein the stabilizer is selected from the group consisting of sulphuric acid, hydrochloric acid, toluene sulfonic acid, phosphoric acid and combinations thereof, and present in an amount in the range from 0.5 to 2% w/w.
16. The synergistic herbicidal composition as claimed in claim 6, wherein the biocide is selected from the group consisting of 20% aqueous dipropylene glycol solution of l,2-benzisothiazolin-3-one, formaldehyde and combinations thereof and present in an amount in the range from 0.01 to 0.50% w/w.
17. The synergistic herbicidal composition as claimed in claim 6, wherein the disintegration agent is selected from citric acid and sodium bicarbonate and present in an amount in the range from 0.5 to 2% w/w.

18. The synergistic herbicidal composition as claimed in claim 6, wherein the thickener is xanthan gum and present in an amount in the range from 0.01 to 0.50% w/w.
19. The synergistic herbicidal composition as claimed in claim 6, wherein the filler is selected from bentonite clay, china clay, silica, kaolin and diatomaceous earth.
20. The synergistic herbicidal composition as claimed in claim 1, wherein the pH of the composition is in the range from about 4 to about 7.