DESC:FIELD OF THE INVENTION
The present invention relates to a synergistic herbicidal composition comprising Penoxsulam, Cyhalofop butyl and 2,4 D or its salts, and to methods of using such compositions to prevent and remove most of weeds in a paddy field, reinforcing preventing effects on barnyard grass, annual chufa, and a plurality of broad-leaf weeds.
BACKGROUND OF THE INVENTION
The protection of crops from weeds and other vegetation which inhibit crop growth is a constantly recurring problem in agriculture. To help combat this problem, researchers in the field of synthetic chemistry have produced an extensive variety of chemicals and chemical formulations effective in the control of such unwanted growth. Chemical herbicides of many types have been disclosed in the literature and a large number are in commercial use.
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."
It is therefore desired to provide an improved herbicidal composition and convenient method which safely and effectively control weed species in the agricultural crops and therefore, there is a constant need for the development and application of synergistic formulations which are not only effective in weed control, but also help in increasing the yield of crop, having potential to manage the challenges of resistance development, shifting of weed flora.
The herbicidal compounds forming the synergistic composition of this invention are independently known in the art for their effects on plant growth.
The search for compounds which have a combination of excellent herbicidal activity towards target weeds and low toxicity towards non-target plants is a continuing one because of factors such as the desire for compounds exhibiting greater activity, better selectivity, lower undesirable environmental impact, lack of phytotoxicity to the locus of application, lower production and market cost and higher effectiveness against weeds resistant to known herbicides. In particular, there exists a need for effective control of broad leaf weeds in turfgrass and in trees and vines.
The present invention is based on the discovery that penoxsulam, cyhalofop butyl and 2,4 D or its salts already known individually for their herbicidal efficacy, display a synergistic effect when applied in combination.
OBJECT OF THE INVENTION
One object of the present invention is to provide herbicide composition that enable efficient and reliable control of grass and broad-leaf weeds.
Another objective of the present invention is to provide a herbicidal composition having persistent herbicidal activity to achieve weed control over a sufficiently long in effect duration and safe to the environment.
Yet another objective of the present invention is to provide a herbicidal composition with low toxicity to humans or other mammals.
Yet another objective of the present invention is to provide a herbicidal composition with accelerated action on harmful plants.
Yet another objective of the present invention is to provide a herbicidal composition comprising penoxsulam, cyhalofop butyl and 2,4 D or its salts with one or more suitable additives.
Yet another objective of the present invention is to provide a process for the preparation of a herbicidal composition comprising penoxsulam, cyhalofop butyl and 2,4 D or its salts.
SUMMARY OF THE INVENTION
The present invention provides herbicidal compositions and methods utilizing herbicidally effective amounts of three herbicidal active ingredients, wherein the first herbicidal active ingredient is Penoxsulam, a sulfonyl urea herbicide; the second herbicidal active ingredient Cyhalofop-butyl, an aryloxyphenoxypropionate herbicide and the third herbicidal active ingredient is 2, 4 D in its salt form preferably 2, 4-D sodium salt. The compositions may also contain agriculturally acceptable excipients.
In an embodiment, the herbicidal composition of the present invention comprises Penoxsulam present in a range from 2% to 5% (w/w); Cyhalofop-butyl is present in a range from 7% to 10% (w/w); and 2, 4 D sodium salt is present in a range from 40% to 60% (w/w).
In an embodiment, the herbicidal composition of the present invention comprises the excipients selected from group comprising a wetting agent, a dispersing agent, a rheology modifier, a buffer, a filler, an adjuvant and combinations thereof.
In an embodiment, the herbicidal composition of the present invention comprises the wetting agent selected from the group comprising dialkyl naphthalene sulphonate sodium salt, alkyl naphthalene sulfonate condensate blend, sodium ligno sulphonate, linear alcohol derivative and polyethylene glycol nonyl phenyl ether ammonium sulfate, present in a range from 4% to 5% w/w.
In an embodiment, the herbicidal composition of the present invention comprises the dispersing agent selected from the group comprising Sodium polyalkyl naphthalene sulfonate, Sodium salt of methyl naphthalene sulfonate, sodium ligno sulphonate, phenol sulfonic acid-formaldehyde-polycondensation as sodium salt, acrylate copolymer, sodium polycarboxylate, sodium methyl oleoyl taurate and sodium lauryl sulphate or combination thereof, present in a range from 4% to 6% w/w.
In an embodiment, the herbicidal composition of the present invention comprises the rheology modifier selected from the group comprising group guar gum, locust bean gum, xanthan gum, carrageenan, alginates, methyl cellulose, carboxymethyl sodium carboxymethylcellulose, hydroxyethylcellulose, modified starches, silicon dioxide, and combination thereof. Preferably, the rheology modifier is silicon dioxide present in an amount of 1.5% w/w.
In an embodiment, the herbicidal composition of the present invention comprises the buffer selected from the group comprising formic acid, oxalic acid, citric acid, phosphoric acid, acetic acid, borate, potassium dihydrogen phosphate, and combination thereof, present in an amount of 2% w/w.
In an embodiment, the herbicidal composition of the present invention comprises the adjuvant selected from the group comprising Polyalkyleneoxide Modified Heptamethyltrisiloxane and blend of amino acids present in an amount of 1.0% w/w.
In an embodiment, the herbicidal composition of the present invention comprises the filler selected from the group comprising starch, corn starch, lactose monohydrate, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, kieselguhr, diatomaceous earth, natural rock, Fuller’s earth, gibbsite, dolomite or pumice; synthetic minerals such as precipitated silica, fumed silica, sodium silicate, silicon dioxide, inorganic salts such as calcium carbonate, ammonium sulfate or other ammonium salts, sodium sulfate, potassium chloride, potassium carbonate and combination thereof, present in an amount of 13% to 38% w/w.
In an embodiment, the herbicidal composition of the present invention is formulated as wettable powder.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. The present application is not intended to be limited to the embodiments shown but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.
Similarly, the words "comprise", "comprises" and "comprising" are to be interpreted inclusively rather than exclusively. Likewise, the terms "include", "including" and "or" should all be construed to be inclusive, unless such a construction is clearly prohibited from the context. However, the embodiments provided by the present disclosure may lack any element that is not specifically disclosed herein. Thus, a disclosure of an embodiment defined using the term "comprising" is also a disclosure of embodiments "consisting essentially of” and "consisting of” the disclosed components. Where used herein, the term "example," particularly when followed by a listing of terms, is merely exemplary and illustrative, and should not be deemed to be exclusive or comprehensive. Any embodiment disclosed herein can be combined with any other embodiment disclosed herein unless explicitly indicated otherwise.
It is to be noted that, as used in the specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The term “active ingredient” (a.i.) or “active agent” used herein refers to that component of the composition responsible for control of weeds, undesired vegetation and grasses.
Unless otherwise specified, % refers to % weight; and % weight refers to % of the weight of the respective component with respect to the total weight of the composition.
As used herein, the terms "herbicide" and "herbicidal active ingredient" refer to an active ingredient that kills, controls, or otherwise adversely modifies the growth of vegetation, particularly undesirable vegetation, such as weeds, when applied in an appropriate amount.
As used herein, a "herbicidally effective amount" may be understood to include an amount of an active ingredient that causes a "herbicidal effect," i.e., an adversely modifying effect including, for instance, a deviation from natural growth or development, killing, regulation, desiccation, growth inhibition, growth reduction, and retardation.
As used herein, applying herbicide or herbicidal composition may be understood to include delivering it directly to the targeted vegetation or to the locus thereof or to the area where control of undesired vegetation is desired. Methods of application include but are not limited to pre-emergently contacting soil or water, post-emergently contacting the undesirable vegetation or area adjacent to the undesirable vegetation.
As used herein, the terms "crops" and "vegetation" can include, for instance, dormant seeds, germinant seeds, emerging seedlings, plants emerging from vegetative propagules, immature vegetation, and established vegetation.
As used herein, immature vegetation may be understood to include small vegetative plants prior to reproductive stage, and mature vegetation may be understood to include vegetative plants during and after the reproductive stage.
The active compounds within the herbicidal composition according to the invention have potent weedicide activity and can be employed for controlling undesired weeds, vegetation, and sedges.
As used herein, the term "effective amount" means the amount of the active substances in the compositions to achieve an observable effect on growth, including the effects of necrosis, death, retardation, prevention, and removal, destruction, or otherwise diminishing the occurrence and activity of the target weed. The effective amount can vary for the various compositions used in the present invention. An effective amount of the compositions will also vary according to the prevailing conditions such as desired herbicidal effect and duration, weather, target species, locus, mode of application, and the like. The terms plants, weeds and vegetation include germinant seeds, emerging seedlings, plants emerging from vegetative propagules and established vegetation.
The present invention aims provide a herbicidal combination, which allows efficient and reliable control of grass and broadleaf weeds. Moreover, the persistence of the herbicidal activity of the combination should be sufficiently long in order to achieve control of the weeds over a sufficient long time period thus allowing a more flexible application. The combination should also have a low toxicity to humans or other mammals. The combinations should also show an accelerated action on harmful plants, i.e., they should effect damaging of the harmful plants more quickly in comparison with application of the individual herbicides.
Penoxsulam is a sulfonylurea herbicide, which is a post germination herbicide having a broad spectrum used in paddy field, belongs to an herbicide group called ALS (acetolactate synthase) inhibitors. It can control and kill Echinochloa crusgalli and annual Cyperus weeds effectively, and it also effective against a variety of leafy weeds. Penoxsulam has the broadest herbicide controlling spectrum among the herbicides used in paddy field, it is characterized by a long-lasting period and a soil activity against Echinochloa crusgalli and a lot of leafy weeds and Cyperus weeds. However, as penoxsulam is a strong acetolactate synthase inhibitor, its herbicidal effect shows slowly, and it takes time for the weeds to die gradually.
Penoxsulam is chemically known as 2-(2,2-difluoroethoxy)-N-(5,8-dimethoxy [1,2,4]-triazolo[1,5-c]pyrimidin-2-yl)-6-(trifluoromethyl)benzenesulfonamide, and has the following structure:


Penoxsulam is the active ingredient of Granite (trademark of Dow AgroSciences LLC), an herbicide designed for postemergence control of annual grasses, sedges, and broadleaf weeds in rice culture. Penoxsulam herbicide is to be used as a foliar spray on dry-seeded rice crops, or as either a foliar spray or a granular formulation on water-seeded rice crops to control broadleaf weeds, aquatic plants, and certain grasses.
Cyhalofop-butyl is a post-emergence, aryloxyphenoxypropionate herbicide, which is used in controlling weeds in rice plantations. Its mode of action involves the inhibition of acetyl-coenzyme A carboxylase (ACCase) biosynthesis. Cyhalofop-butyl may be used as a reference standard in the determination of Cyhalofop-butyl in rice samples using liquid chromatography coupled with diode array detector (LC-DAD).
Cyhalofop butyl is chemically known as 2-Butyl-(R)-2-[4(4-cyano-2-fluorophenoxy) phenoxy] propionate, and has the following structure:

2,4-D is chemically known as 2,4- Dichlorophenoxy acetic acid. Usually 2,4-D is used in its salt form. It is a systemic herbicide which kills most broadleaf weeds by causing uncontrolled growth in them but most grasses such as cereals, lawn turf, and grassland are relatively unaffected. 2,4-D acts by mimicking the action of the plant growth hormone auxin, which results in uncontrolled growth and eventually death in susceptible plants. It is absorbed through the leaves and is translocated to the meristems of the plant. Uncontrolled, unsustainable growth ensues, causing stem curl-over, leaf withering, and eventual plant death. Preferably, 2,4 D salt suitable for use in the present invention is 2,4 D-Sodium salt. The chemical structure of 2,4-D is

The herbicidal composition in addition to herbicidal actives further contains a support, an adjuvant and/or a surfactant. During application, a common adjuvant can be mixed with the composition.
In practice, it is preferable to use the synergistic composition of the present invention in mixtures containing a herbicidally effective amount of the herbicidal components along with at least one agriculturally acceptable excipient or carrier. Suitable excipients or carriers should not be phytotoxic to valuable crops, particularly at the concentrations employed in applying the compositions for selective weed control in the presence of crops and should not react chemically with herbicidal components or other composition ingredients. Such mixtures can be designed for application directly to weeds or their locus or can be concentrates or formulations that are normally diluted with additional carriers and excipients before application.
Suitable excipients may be a solid or liquid and are generally a substance commonly used in formulation processing process, for example, natural or regenerated minerals, solvents, dispersing agents, wetting agents, rheology modifiers, filler, buffer, adhesives, thickeners, stabilizers, binders, or fertilizers. Other excipients commonly used in agricultural compositions include compatibility agents, antifoam agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, sticking agents, dispersing agents, thickening agents, freezing point depressants, antimicrobial agents, and the like. The compositions may also contain other compatible components, for example, other herbicides, plant growth regulators, fungicides, insecticides, and the like and can be formulated with liquid fertilizers or solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like that are used to deliver nutrients to turfgrass.
Accordingly, the inventors of the present invention have formulated a synergistic herbicidal composition, comprising: Penoxsulam, Cyhalofop butyl and 2,4 D Na and excipients; wherein Penoxsulam is present in a range from 2% to 5% (w/w), Cyhalofop butyl is present in a range from 7% to 10% (w/w), 2,4 D Na is present in a range from 40% to 60% (w/w).
The novel herbicidal composition of the present invention may be formulated as Granular composition (GR), Capsule suspension (CS), Dispersible concentrate (DC), Dustable powder (DP), Powder for dry seed treatment (DS), Emulsifiable concentrate (EC), Emulsifiable granule (EG), Emulsion water-in-oil (EO), Emulsifiable powder (EP), Emulsion for seed treatment (ES), Emulsion oil-in-water (EW), Flowable concentrate for seed treatment (FS), Granules (GR), Micro-emulsion (ME), Oil-dispersion (OD), Oil miscible flowable concentrate (OF), Oil miscible liquid (OL), Oil dispersible powder (OP), Suspension concentrate (SC), Suspension concentrate for direct application (SD), Suspo-emulsion (SE), Water soluble granule (SG), Soluble concentrate (SL), Spreading oil (SO), Water soluble powder (SP), Water soluble tablet (ST), Ultra-low volume (ULV) suspension, Tablet (TB), Ultra-low volume (ULV) liquid, Water dispersible granules (WG), Wettable powder (WP), Water dispersible powder for slurry seed treatment (WS), Water dispersible tablet (WT), a mixed formulation of CS and SC (ZC), a mixed formulation of CS and SE (ZE), a mixed formulation of CS and EW (ZW).
Preferably, the synergistic herbicidal composition is in the form of wettable powder (WP) and the additives are selected from the group comprising a wetting agent, a dispersing agent, a rheology modifier, a buffer, a filler, an adjuvant and combinations thereof.
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 suitable for use in the present invention are dialkyl naphthalene sulphonate sodium salt, alkyl naphthalene sulfonate condensate blend, sodium ligno sulphonate, linear alcohol derivative and polyethylene glycol nonyl phenyl ether ammonium sulfate. Wetting agent is present in a range from 4% to 5% (w/w).
It is generally observed that solid particles in a liquid undergo spontaneous aggregation to form lumps. Hence it is recommended to add a dispersant or a dispersing agent which prevents aggregation of solid particles and keeps them suspended in the fluid. One or more dispersing agents may be used in the synergistic composition of the present invention. Accordingly, the composition of the present invention preferably contains a dispersing agent suitable for use in the present invention are Sodium polyalkyl naphthalene sulfonate, Sodium salt of methyl naphthalene sulfonate, Phenol sulfonic acid-formaldehyde, sodium ligno sulphonate, acrylate copolymer, phenol sulfonic acid-formaldehyde-polycondensation as sodium salt, sodium polycarboxylate, acrylate copolymer, sodium methyl oleoyl taurate and sodium lauryl sulphate or combination thereof. Dispersing agent is present in a range from 4% to 6% (w/w) in the compositions of the present invention.
The rheology modifier is any material that alters the rheology of a composition to which it is added. Suitable rheology modifier useful in accordance with the invention are natural polymers selected from the group guar gum, locust bean gum, xanthan gum, carrageenan, alginates, methyl cellulose, carboxymethyl sodium carboxymethylcellulose, hydroxyethylcellulose, modified starches, silicon dioxide and equivalent products thereof, preferably used is silicon dioxide. The rheology modifier is present in an amount of 1.5 % (w/w).
Suitable buffer useful in accordance with the invention are formic acid, oxalic acid, citric acid, phosphoric acid, acetic acid, borate, potassium dihydrogen phosphate. The buffer is present in an amount of 2% (w/w).
Adjuvants are used in the present invention for increasing biological efficacy of agrochemicals. Suitable adjuvants for the purpose of the present invention are selected from the group comprising Polyalkyleneoxide Modified Heptamethyltrisiloxane and blend of amino acids. The adjuvants are present in an amount of 1% (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 starch, corn starch, lactose monohydrate, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, kieselguhr, diatomaceous earth, natural rock, Fuller’s earth, gibbsite, dolomite or pumice; synthetic minerals such as precipitated silica, fumed silica, sodium silicate, silicon dioxide; inorganic salts such as calcium carbonate, ammonium sulfate or other ammonium salts, sodium sulfate, potassium chloride, potassium carbonate. The filler may be used alone or in combination thereof. Filler is present in a range from 13% to 38% (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 herbicide composition 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.
It is generally preferred to use the synergistic composition of the present invention in combination with herbicides that are selective for the crop being treated and which complement the spectrum of weeds controlled by these compounds at the application rate employed. It is further generally preferred to apply the synergistic composition of the present invention and other complementary herbicides at the same time, either as a combination formulation or as a tank mix.
The present compositions can be applied to weeds or their locus by the use of conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation water, and by other conventional means known to those skilled in the art.
The present invention is 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 reagent used in the example were obtained or are available from the chemical suppliers.
Examples:
Example 1: Preparation of composition of Penoxsulam, Cyhalofop butyl and 2,4-D Na in wettable powder (WP) form.
The composition of Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt in wettable powder form is prepared by following steps as below:
Step 1: In a pre-blender reactor weighing all raw materials and excipients according to the batch size, as illustrated below:
Filler,
Penoxsulam,
Cyhalofop butyl,
2,4-D sodium salt,
Wetting agent,
Dispersing agent,
Rheology modifier, and
Buffer.
Step 2: Pre-mixing the sample for 1 hour in a pre-blender,
Step 3: Milling the sample through air jet machine at inlet pressure 2-3 kg/cm2, grinding pressure 6 kg/cm2 to get desired particle size (< 8 micron),
Step 4: Collecting the milled material, and post blending the sample for 1hr in a post blender,
Step 5: Sending the sample for all physico-chemical analysis,
Step 6: Packing the sample in suitable packaging.

Example 2: Compositions of the present invention
The illustrative embodiments show the composition of Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt in wettable powder form in different amount as follows:
Table-1: Penoxsulam 2.5% + Cyhalofop butyl 7.5% + 2,4-D sodium salt 50% (WP)
S. No. Ingredients Function % (w/w)
1. Penoxsulam Herbicide 2.5
2. Cyhalofop butyl Herbicide 7.5
3. 2,4-D Na Herbicide 50
4. Alkylnaphthalene sulfonate condensate blend Wetting agent 4.0
5. Phenol sulfonic acid-formaldehyde. Dispersing agent 2.0
6. Sodium Polyalkyl naphthalene sulphonate Dispersing agent 2.0
7. Silicon dioxide Rheology modifier 1.5
8. Oxalic acid Buffer 2.0
9. China clay Filler 28.5
Total 100

Table-2: Penoxsulam 2% + Cyhalofop butyl 7% + 2,4-D sodium salt 45% (WP)
S. No. Ingredients Function % (w/w)
1. Penoxsulam Herbicide 2.0
2. Cyhalofop butyl Herbicide 7.0
3. 2,4 D Na Herbicide 45
4. Alkylnaphthalene sulfonate condensate blend Wetting agent 5.0
5. Phenol sulfonic acid-formaldehyde-polycondensation as sodium salt Dispersing agent 3.0
6. Acrylate copolymer Dispersing agent 3.0
7. Citric acid Buffer 2.0
8. Lactose Filler 33.0
Total 100

Table-3: Penoxsulam 3% + Cyhalofop butyl 8% + 2,4-D sodium salt 40% (WP)
S. No. Ingredients Function % (w/w)
1. Penoxsulam Herbicide 3.0
2. Cyhalofop butyl Herbicide 8.0
3. 2,4 D Na Herbicide 40
4. Dialkyl naphthalene sulphonate sodium salt Wetting agent 4.0
5. Sodium salt of methyl naphthalene sulfonate Dispersing agent 2.0
6. Phenol sulfonic acid-formaldehyde-polycondensation as sodium salt Dispersing agent 2.0
7. Silicon dioxide Rheology modifier 1.5
8. Phosphoric acid Buffer 2.0
9. Bentonite clay Filler 37.5
Total 100

Table-4: Penoxsulam 4% + Cyhalofop butyl 9% + 2,4-D sodium salt 55% (WP)
S. No. Ingredients Function % (w/w)
1. Penoxsulam Herbicide 4.0
2. Cyhalofop butyl Herbicide 9.0
3. 2,4 D Na Herbicide 55.0
4. Linear alcohol derivative Wetting agent 4.0
5. Sodium polycarboxylate Dispersing agent 2.0
6. Sodium methyl oleoyl taurate Dispersing agent 2.0
7. Silicon dioxide Rheology modifier 1.5
8. Polyalkyleneoxide Modified Heptamethyltrisiloxane Adjuvant 1.0
9. Starch Filler 21.5
Total 100

Table-5: Penoxsulam 5% + Cyhalofop butyl 10% + 2,4, D sodium salt 60% (WP)
S. No. Ingredients Function % (w/w)
1. Penoxsulam Herbicide 5.0
2. Cyhalofop butyl Herbicide 10.0
3. 2,4 D Na Herbicide 60.0
4. Polyethyleneglycol Nonylphenyl ether ammonium sulfate Wetting agent 4.0
5. Sodium ligno sulphonate Dispersing agent 2.0
6. Sodium lauryl sulphate Dispersing agent 2.0
7. Silicon dioxide Rheology modifier 1.5
8. Formic acid, Buffer 2.0
9. Potassium carbonate Filler 13.5
Total 100
Example 3: Efficacy study for combination of Penoxsulam, Cyhalofop butyl and 2,4 D sodium salt in wettable powder form
FIELD AND SYNERGY STUDIES
The weed control activity of the individual herbicides of the invention and their combinations were evaluated on weeds such as Cyperus difformis, Cyperus iria, Echinochloa colonum, Echinochloa crusgalli, Leptochloa chinensis, Monochoria vaginalis, Ludwigia parviflora & Eclipta alba. Trials were conducted with randomized block design with net plot size of 5m x 6m. Each trial was replicated four times and conducted under GEP guidelines. Spraying was done with manual operated backpack knapsack sprayer with 300 L of water spray volume per hectare at post-emergence (15-20 days after transplanting/sowing of rice) application timing. Such field trials were carried out at various locations to generate independent data, the locations were chosen randomly across India.
Visual observations were recorded on percent weed control for individual weeds on whole plot basis at 21 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. Analyzing Herbicide Interactions: A Statistical Treatment of Colby's Method. Weed Technology 2: 304-309

The herbicide combination, application rates, plant species tested, and results are given in the following tables:
Table 6: Table 6 demonstrates synergy on weeds using the combination of Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 21 days of application. The target weeds were Cyperus iria and Cyperus difformis and the results are recorded in the table 6 below.
Table 6: Synergistic effect of the herbicidal composition on weeds Cyperus iria and Cyperus difformis
Active Dose (GAH) % Weed Control of Cyperus iria % Weed Control of Cyperus difformis
Expected Observed Expected Observed
Penoxsulam 30 75 70
Cyhalofop butyl 90 20 15
2,4-D sodium salt 600 65 60
Penoxsulam + Cyhalofop butyl + 2,4 D sodium salt 30 + 90 + 600 93 100 89.8 99
Ratio of O/E 1.08 1.10
(GAH – gram active per hectare)
The results in table 6 clearly demonstrates synergy between Penoxsulam, Cyhalofop butyl and 2,4 D sodium salt 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.
Table 7: Table 7 demonstrates synergy on weeds using the combination of Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 21 days of application. The target weeds were Echinochloa colonum, Echinochloa crusgalli and Leptochloa chinensis. The results are recorded in the table 7 below.
Table 7: Synergistic effect of the herbicidal composition on weeds Echinochloa colonum, Echinochloa crusgalli and Leptochloa chinensis
Active Dose (GAH) % Weed Control of Echinochloa colonum % Weed Control of Echinochloa crusgalli % Weed Control of Leptochloa chinensis
Expected Observed Expected Observed Expected Observed
Penoxsulam 30 75 70 25
Cyhalofop butyl 90 50 45 65
2,4-D sodium salt 600 5 10 10
Penoxsulam + Cyhalofop butyl + 2,4 D Sodium salt 30 + 90 + 600 88.12 95 85.15 92 76.37 85
Ratio of O/E 1.08 1.08 1.11
(GAH – gram active per hectare)
The results in table 7 clearly demonstrates efficacy of Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt against weeds like Echinochloa colonum, Echinochloa crusgalli and Leptochloa chinensis. The higher ratio of the observed and the expected efficacy clearly demonstrates the synergistic effect of the combination.
Table 8: Table 8 demonstrates synergy on weeds using the combination Penoxsulam, Cyhalofop butyl and 2,4-D sodium salt. The field trials were carried out in India at various locations. The percentage efficacy was calculated after 21 days of application. The target weeds were Monochoria vaginalis, Ludwigia parviflora and Eclipta alba. The results are recorded in the table 8 below.
Active Dose (GAH) % Weed Control of Monochoria vaginalis % Weed Control of Ludwigia parviflora % Weed Control of Eclipta alba
Expected Observed Expected Observed Expected Observed
Penoxsulam 30 78 80 80
Cyhalofop butyl 90 10 15 10
2,4-D Sodium salt 600 70 75 75
Penoxsulam + Cyhalofop butyl + 2,4 D sodium salt 30 + 90 + 600 94.06 100 95.75 100 95.5 100
Ratio of O/E 1.06 1.04 1.05
(GAH – gram active per hectare)
The results in table 8 clearly demonstrates efficacy of Penoxsulam, Cyhalofop butyl and 2,4-D Sodium salt 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.
The combinations of the present invention have several advantages over solo application of either Penoxsulam, Cyhalofop butyl and 2,4-D or its salt and, likewise, over any binary combination of these herbicides. The combination of the present invention shows enhanced herbicide action in comparison with the herbicide action of solo action of Penoxsulam, Cyhalofop butyl or 2,4-D or its salt against undesirable vegetation. Moreover, the combinations of the invention show a persistent herbicidal activity, even under difficult weathering conditions, and minimizes the risk of weeds escaping. The combinations are generally non-toxic or of low toxicity against mammals. Apart from that, the combinations of the present invention show superior crop compatibility with certain conventional crop plants and with herbicide tolerant crop plants, i.e., their use in these crops leads to a reduced damage of the crop plants and/or does not result in increased damage of the crop plants. Thus, the combinations of the invention can also be applied after the emergence of the crop plants. The combinations of the present invention may also show an accelerated action on harmful plants, i.e., they may affect damage of the harmful plants more quickly in comparison with solo or binary applications of the at least three herbicides involved.
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. ,CLAIMS:We claim:

1. A herbicidal composition comprising a sulfonyl urea herbicide, an aryloxyphenoxypropionate herbicide, a 2, 4 D in its salt form in effective amounts and excipients.
2. The composition as claimed in claim 1, wherein the sulfonyl urea herbicide is Penoxsulam, the aryloxyphenoxypropionate herbicide is Cyhalofop-butyl and the 2, 4 D in its salt form is 2, 4-D sodium salt.
3. The composition as claimed in claim 2, wherein Penoxsulam is present in a range from 2% to 5% (w/w); Cyhalofop-butyl is present in a range from 7% to 10% (w/w); and 2, 4 D sodium salt is present in a range from 40% to 60% (w/w).
4. The composition as claimed in claim 1, wherein the excipients are selected from group comprising a wetting agent, a dispersing agent, a rheology modifier, a buffer, a filler, an adjuvant and combinations thereof.
5. The composition as claimed in claim 4, wherein the wetting agent is selected from the group comprising dialkyl naphthalene sulphonate sodium salt, alkyl naphthalene sulfonate condensate blend, sodium ligno sulphonate, linear alcohol derivative and polyethylene glycol nonyl phenyl ether ammonium sulfate, present in a range from 4% to 5% w/w.
6. The composition as claimed in claim 4, wherein the dispersing agent is selected from the group comprising Sodium polyalkyl naphthalene sulfonate, Sodium salt of methyl naphthalene sulfonate, sodium ligno sulphonate, phenol sulfonic acid-formaldehyde-polycondensation as sodium salt, acrylate copolymer, sodium polycarboxylate, sodium methyl oleoyl taurate and sodium lauryl sulphate or combination thereof, present in a range from 4% to 6% w/w.
7. The composition as claimed in claim 4, wherein the rheology modifier is selected from the group comprising guar gum, locust bean gum, xanthan gum, carrageenan, alginates, methyl cellulose, carboxymethyl sodium carboxymethylcellulose, hydroxyethylcellulose, modified starches, silicon dioxide, and combination thereof, present in an amount of 1.5% w/w.
8. The composition as claimed in claim 4, wherein the buffer is selected from the group comprising formic acid, oxalic acid, citric acid, phosphoric acid, acetic acid, borate, potassium dihydrogen phosphate, and combination thereof, present in an amount of 2% w/w.
9. The composition as claimed in claim 4, wherein the filler is selected from the group comprising starch, corn starch, lactose monohydrate, pyrophyllite, montmorillonite, attapulgite, bentonite clay, china clay, kieselguhr, diatomaceous earth, natural rock, Fuller’s earth, gibbsite, dolomite or pumice; synthetic minerals such as precipitated silica, fumed silica, sodium silicate, silicon dioxide, inorganic salts such as calcium carbonate, ammonium sulfate or other ammonium salts, sodium sulfate, potassium chloride, potassium carbonate and combination thereof, present in an amount of 13% to 38% w/w.
10. The composition as claimed in claim 1, wherein the composition is formulated as wettable powder.