DESC:FIELD OF THE INVENTION

This invention relates to herbicidal compositions and methods related thereto. More particularly, the present invention relates to synergistic herbicidal compositions comprising an herbicidal pyrazole derivative and at least one co-herbicide selected from a range of co-herbicides. It further relates to the method of preparation and use of the aforesaid herbicidal compositions for controlling undesired vegetation in crops, especially for management of weed flora in soybean.

BACKGROUND OF THE INVENTION

Weeds damage agricultural crops and reduces productivity by competing with the crop and forage plants for mineral nutrients, nitrogen, water, and sunlight. Several methods of using herbicides to control or eliminate weedy species are known in the art. 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 weeds for control of germinating weed seeds without harming the desired plant species. Post-emergence herbicides are applied after planting and over the top of establishing or established plants for control of unwanted plant species.

Generally, current methods of attempting to control weeds include applications of pre-emergent herbicides followed by post emergent herbicides i.e. sequential applications of herbicides to address the issue of weeds in agricultural crop cultivation. Most of the crop lands under cultivation are weeded by hand, hence, much human effort is expended in raising crops. Most of the times, the dosage used varies as the herbicide selection is not based on the technical knowhow which results in poor weed control affecting the productivity of the crop.

Other conventional methods of producing weed free crops include the use of different combinations of herbicides such as tank mixing of herbicides to address the issue of emerged weeds without having proper application knowledge of the weed spectrum of individual herbicides. In such usage the chances of varied dosage of individual herbicides end up with poor weed control. Such improper practices also leads to serious complications such as but not limited to increase in population of escape weeds, herbicide tolerance & resistance development, shifting of weed flora etc. However, successful weed management is essential for economical crop production.

To overcome these types of problems, a need arises for the use of pre-mix (ready-mix) herbicidal compositions in which more than one type of herbicide is present in appropriate contents and delivery form i.e. the formulation. It is, nonetheless, difficult to determine appropriate combinations of herbicides in view of the considerable number of different types of herbicides available and the plurality of individual herbicides within each such type.

Generally, pendimethalin and imazethapyr combination is used to control weeds of soybean crop. Farmers are using different combinations such as of pendimethalin and chlorimuron ethyl to address the weed flora of soybean crop without completely knowing the mode of action and the weed spectrum. At times farmers’ use to underdose the product (s) and this leads to resistance development or poor control of the weeds.

The herbicides or combination of herbicides can be applied in different ways for example sequential application, tank-mix application and pre-mix application. In sequential application, farmers use different herbicides, wherein the herbicide selection is not based on the technical knowhow and herbicides having the same mode of action are being used, which leads to resistance development. In tank-mix application, farmers use different combinations of herbicides, most of the times without having training to properly mix products. Homemade tank mixes may therefore not be as stable as a pre-mix. The tank-mix 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 products.

The pre-mix application is a combination of two or more herbicides as active ingredients but the rates of the active ingredients are unchangeable, the components rates and formulation are optimized during development, hence no mixing, chemical compatibility or stability issue exists. The pre-mix application also helps in reducing the development of herbicides resistance.

The sequential application and tank-mix application of herbicides with inappropriate doses, when employed to address weeds of soybean, result in development of herbicide resistance.

It is therefore desired to provide an improved 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.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a synergistic herbicidal composition comprising a pyrazole derivative and at least one co-herbicide selected from a range of co-herbicides and and agriculturally acceptable formulation additives said compositions having a broader spectrum of weed control than each individual herbicide constituent, whilst retaining the selectivity of herbicidal action of each of the constituent.

A further object of the present invention is to provide synergistic herbicidal compositions which, when applied as pre plant incorporation (PPI) and Pre-emergence (PE), display an enhanced and broader spectrum of herbicidal activity with regard to the crops being treated.

Another object and advantage of the present invention is to provide a stable synergistic herbicidal composition that shows technical advancement over the existing herbicides or combination of herbicides.

A further object of the present invention is to provide a method of controlling the germination and growth of undesired vegetation in a selective manner with regard to crops, e.g. weed flora in soybean, being treated, which comprises applying to the crop, pre plant incorporation or pre-emergence-, preferably a pre-mix composition according to the present invention.

A further object of the present invention is to provide a herbicidal composition that efficaciously contributes in Herbicide Resistance Management (HRM).

Yet another object and advantage of the present invention is to provide a cost-effective and convenient method for the preparation of said composition, which is effective against a wide variety of undesired vegetation in crops, especially for management of weed flora in soybean.

Another object of the invention is to provide a stable synergistic herbicidal composition which meets the environmental and economic requirements imposed on modern-day herbicides which are continuously increasing, with regard to, for example, to the spectrum of action, toxicity, selectivity, application rate, formation of residues, and favorable preparation ability.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a synergistic herbicidal composition comprising an herbicidal effective amount of a pyrazole derivative as a first component (a) and at least one co-herbicide selected from a range of co-herbicides as a second component (b) and agriculturally acceptable formulation additives (c) is provided.

Accordingly, the present invention relates to a stable synergistic herbicidal composition for management of weeds comprising a herbicidal pyrazole derivative as a first component (a) and at least one co-herbicide selected from a range of co-herbicides as a second component (b), and agriculturally acceptable formulation additives (c), wherein weight percentage of (a) is 8.5 to 80% and 25 to 76%, weight percentage of (b) is 1.5 to 15% and 5 to 14% and weight percentage of (c) is 5 to 90% and 10 to 70%.

Preferred pyrazole derivative i.e. component (a) according to the present invention, not being limited to, is pyroxasulfone, i.e. 3-[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole.

Preferred co-herbicides according to the present invention are triazolopyrimidine sulfonamides including, not being limited to, diclosulam, cloransulam-methyl, florasulam, flumetsulam, metosulam, penoxsulam, and pyroxsulam or an agriculturally acceptable salt, carboxylic acid, carboxylate salt, or ester thereof.

Preferred triazolopyrimidine herbicides i.e. component (b) is diclosulam.

The invention also relates to an herbicide formulation, which comprises a herbicidal active composition as defined herein and agriculturally acceptable formulation additives.

Thus, in one aspect, this invention provides a synergistic herbicidal composition comprising a herbicidal pyrazole derivative and at least one co-herbicide selected from a range of co-herbicides and and agriculturally acceptable formulation additives as defined above.

In another aspect, the present invention provides the process for preparing a synergistic herbicidal composition comprising an herbicidal pyrazole derivative and at least one co-herbicide selected from a range of co-herbicides and agriculturally acceptable formulation additives as defined above.

It is known that combined application of certain different herbicides with specific action might result in an enhanced activity of an herbicide component in comparison with a simple additive action. Such an enhanced activity is also termed a synergism or synergistic activity. As a consequence, it is possible to reduce the application rates of herbicidal active compounds required for controlling the weeds, increasing the spectrum of control of weeds or may be improved herbicidal performance.

The term “herbicide,” as used herein, means an active ingredient that kills, controls, or otherwise adversely modifies the growth of vegetation. A “herbicidal effective amount” is an amount of an active ingredient that causes a “herbicidal effect,” i.e., an adversely modifying effect and includes deviations from, for instance, natural development, killing, regulation, desiccation, and retardation. The terms “plants” and “vegetation” can include, for instance, germinant seeds, emerging seedlings, and established vegetation.

As used herein, controlling undesirable vegetation means preventing, reducing, killing, or otherwise adversely modifying the development of plants and vegetation. Described herein are methods of controlling undesirable vegetation through the application of certain herbicide combinations or compositions. Methods of application include, but are not limited to applications to the vegetation or locus thereof, e.g., application to the area adjacent to the vegetation, as well as pre-emergence, post-emergence, foliar (broadcast, directed, banded, spot, mechanical, over-the-top, or rescue), and in-water applications (emerged and submerged vegetation, broadcast, spot, mechanical, water-injected, granular broadcast, granular spot, shaker bottle or stream spray) via hand, backpack, machine, tractor, or aerial application methods.

Surprisingly, the compositions according to the invention have better herbicidal activity against the target weed would have been expected by the herbicidal activity of the individual compounds. In other words, the joint action of herbicide pyrazole (a) and the at least one herbicide (b) results in an enhanced activity against harmful plants in the sense of a synergy effect (synergism). Moreover, the compositions of the present invention provide good pre plant incorporation (PPI) and Pre-emergence (PE) herbicidal activity, i.e. the compositions are particularly useful for combating/controlling weeds after their emergence.

Moreover, it has been found that the use of a triazolopyrimidine herbicide, in combination with certain herbicidal pyrazole derivatives, extends the spectrum of herbicidal activity without loss of crop selectivity. Therefore the said combinations represent an important technological advance. The term "combination" as used in this specification refers to the "combination" of a herbicidal pyrazole derivative (pyroxasulfone) component (a) and a triazolopyrimidine herbicide (diclosulam) component (b).

The compositions of the present invention are suitable for controlling a large number of weeds, including monocotyledonous weeds, in particular annual weeds such as gramineous weeds (grasses) including Echinochloa species such as barnyard grass (Echinochloa crusgalli var. crus-galli), Digitaria species such as crabgrass (Digitaria sanguinalis), Setaria species such as green foxtail (Setaria viridis) and giant foxtail (Setaria faberii), Sorghum species such as johnsongrass (Sorghum halepense Pers.), Avena species such as wild oats (Avena fatua), Cenchrus species such as Cenchrus echinatus, Bromus species, Lolium species, Phalaris species, Eriochloa species, Panicum species, Brachiaria species, annual bluegrass (Poa annua), blackgrass (Alopecurus myosuroides), Aegilops cylindrica, Agropyron repens, Apera spica-venti, Eleusine indica, Cynodon dactylon and the like.

The compositions of the present invention are also suitable for controlling a large number of dicotyledonous weeds, in particular broad leaf weeds including Polygonum species such as wild buckwheat(Polygonum convolvolus), Amaranthus species such as pigweed (Amaranthus retroflexus), Chenopodium species such as common lambsquarters (Chenopodium album L.), Sida species such as prickly sida (Sida spinosaL.), Ambrosia species such as common ragweed (Ambrosia artemissifolia), Acanthospermum species, Anthemis species, Atriplex species, Cirsium species, Convolvulus species, Conyza species, Commelina species, Datura species, Euphorbia species, Geranium species, Galinsgo species, morning glory (Ipomoea species), Lamium species, Malva species, Matricaria species, Sysimbrium species,Solanum species, Xanthium species, Veronica species, Viola species, common chickweed (Stellaria media), velvetleaf (Abutilon theophrasti), Hemp sesbania (Sesbania exaltata Cory), Anoda cristata, Bidens pilosa, Brassica kaber, Capsella bursa-pastoris, Centaurea cyanus, Galeopsis tetrahit, Galium aparine, Helianthus annuus, Desmodium tortuosum, Kochia scoparia, Mercurialis annua,Myosotis arvensis,Papaver rhoeas, Raphanus raphanistrum, Salsola kali, Sinapis arvensis, Sonchus arvensis, Thlaspi arvense, Tagetes minuta, Richardia brasiliensis, and the like.

The compositions of the present invention are in particular suitable for combating/controlling undesired vegetation in rice, wheat, corn, sugarcane, soybean, pulse crops, potato etc.

The compositions of the present invention can be applied in conventional manner by using techniques a skilled person is familiar with. Suitable techniques include spraying, atomizing, dusting, spreading or watering. The type of application depends on the intended purpose in a well-known manner; in any case, the techniques should ensure the finest possible distribution of the active ingredients according to the invention.

The compositions can be applied as PPI (pre-plant incorporation) i.e. before the sowing of main crop or PE (Pre-Emergence), i.e. after the sowing of crop but before emergence of the undesirable plants (weeds).

Since the composition show good crop tolerance, even when the crop has already emerged, they can be applied after seeding of the crop plants and in particular during or after the emergence of the crop plants.

The present invention also relates to formulations of the compositions according to the present invention. The formulations contain, besides the composition, one or more kinds of agriculturally acceptable formulation additives (c) such as surfactant, carrier, binder, disintegrate, pH adjuster, thickener, preservative, anti-freezing agent, defoamers and/or coloring agent or a combination thereof.

Suitable surfactants (a dispersant, a wetting agent, a spreader, an adjuvant for penetration enhancement, rain fastness, soil leaching control etc.) are nonionic or anionic or a combination of these surfactants. It is preferred to use more than two kinds of surfactants which have different chemical structure. Suitable surfactants are, for example, sugar esters (such as sorbitan monolaurate, polyoxyethylene sorbitan monolaurrate), polyoxyethylene alkyl ethers (such as polyoxyethylene lauryl ether or polyoxyethylene coconut fatty alcohol ether), polyoxyethylene aryl ethers (such as polyoxyethylene nonylphenyl ether or polyoxyethylene trystyrylphenyl ether), polyoxyethylene vegetable oil ethers (such as polyoxyethylene castor oil), polyoxyethylene fatty acid esters (such as polyoxyethylene monolaurate), polyoxyethylene polyoxypropylene block co-polymers, polyoxyethylene alkyl amines (such as polyoxyethylene stearyl fatty amine), alkyl sulfates (such as sodium lauryl sulfate), polyoxyethylene alkyl ether sulfates (such as sodium polyoxyethylene lauryl ether sulfate), polyoxyethylene aryl ether sulfates (such as sodium polyoxyethylene nonylphenyl ether sulfate or ammonium polyoxyethylene tristyrylphenyl ether sulfate), alkane sulfonates (such as sodium dodecyl sulfonate), ‘alpha’-olefin sulfonate, aryl sulfonates (such as sodium dodecylbenzene sulfonate, sodium naphthalene sulfonate, sodium alkylnaphthalene sulfonate, sodium naphthalene sulfonate formaldehyde condensate or sodium alkyl diphenyl ether sulfonate), alkylsulfosuccinates (such as sodium dioctylsulfosuccinate), lignosulfonates, polyoxyethylene alkyl ether phosphate, polyoxyethylene aryl ether phosphates (such as polyoxyethylene phenyl ether phosphate) and polyoxyethylene polyoxypropylene block co-polymer phosphate or a combination thereof.

Suitable liquid carriers are, for example, water, alcohols (such as ethanol, propanol, isopropanol ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol, glycerin), polyol ether (such as ethylene glycol monopropyl ether, diethylene glycol monomethyl ether), ketones (such as methyl isobutyl ketone, cyclohexanone), ethers (such as dipropyl ether, dioxane, ethylene glycol monoethyl ether, tetrahydrofuran, dipropylene glycol dimethyl ether), aliphatic hydrocarbons (such as normal paraffin, naphthene, isoparaffin, kerosene, mineral oil), aromatic hydrocarbons (such as xylene, solvent naphtha, alkyl naphthalene), esters (such as ethyl acetate, diisopropyl phthalate, dimethyl adipate), lactones (such as gamma-butyrolactone), amides (such as dimethylformamide, N-methylpyrrolidone, N,N-dimethyldecanamide), nitriles (such as acetonitrile), sulfur compounds (such as dimethyl sulfoxide) and vegetable oils (such as soybean oil, rapeseed oil, cotton seed oil). These liquid carriers may be used alone or in a combination of two or more kinds or a combination thereof.
Suitable solid carriers are, for example, natural minerals (such as talc, kaolinite, pyrophyllite, montmorillonite, attapulgite, bentonite, calcite, diatomaceous earth), synthetic minerals (such as precipitated silica, fumed silica and calcium carbonate), inorganic salts (such as calcium carbonate, ammonium sulfate, sodium sulfate, potassium chloride) and organic materials (such as urea, lactose, starch, cellulose, plant powders). These solid carriers may be used alone or in a combination of two or more kinds or a combination thereof.

Suitable binders are, for example, polyvinyl alcohol, dextrin, denatured dextrin, soluble starch, carboxymethyl cellulose and bentonite or a combination thereof.
Suitable disintegrants are, for example, sodium tripolyphosphate, sodium hexametaphosphate, carboxymethyl cellulose, sodium polycarbonate and bentonite or a combination thereof.

Suitable pH adjusters are, for example, sodium or potassium carbonate, sodium or potassium hydrogen carbonate, sodium or potassium dihydrogenphosphate, disodium or dipotassium hydrogenphosphate, citric acid, malic acid and triethanolamine or a combination thereof.

Suitable thickeners are, for example, xanthan gum, welan gum, guar gum, polyvinyl alcohol, carboxymethyl cellulose and its salt, silica and bentonite or a combination thereof.

Suitable preservatives are, for example, 4-hydroxybenzoic acid esters, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-one or a combination thereof.

Suitable anti-freezing agents are, for example, glycerin, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and urea or a combination thereof.

Suitable defoamers are, for example, silicone compounds and organic fluorine compounds or a combination thereof.

Suitable coloring agents are, for example, organic dyestuffs (such as azo dye, phthalocyanine dye or alizarin dye) and inorganic pigments (such as iron oxide) or a combination thereof.

The formulation may be in the form of a single package formulation for pre-mix application containing both the herbicide-A and at least one herbicide B together with agriculturally acceptable formulation additives.

The formulation may be in the form of a two package formulation, wherein one package contains a formulation herbicide A while the other package contains a formulation of the at least one herbicide B and wherein both formulations contain agriculturally acceptable formulation additives. In the case of two package formulations the formulation containing herbicide A and the formulation containing the herbicide B are mixed prior to application. Preferably the mixing is performed as a tank mix, i.e. the formulations are mixed immediately prior or upon dilution with water.

In the formulation of the present invention the active ingredients, i.e. herbicide A, herbicide B and optional further actives are formed to several types of formulations such as not being limited to, emulsifiable concentrate (EC), wettable powder (WP), water dispersible granules (WG), suspension concentrate (SC) etc.

In one embodiment of the present invention, the composition of the wettable powder formulation is provided. The composition of wettable powder comprises pyrazole derivative and triazolopyrimidine sulfonamide as active ingredients, surfactant and carrier. Other formulation additives such as pH adjuster and colorant may be additionally used.

A method for preparing the wettable powder formulation of the present invention is also provided. The wettable powder formulation can be prepared by mixing the active ingredients, surfactant and carrier. Usually active ingredients, surfactant, carrier and other formulation additives are mixed uniformly in a mixer and milled by a mill such as an air jet mill to median diameter 5 to 50 micrometer.

In another embodiment of the present invention, the composition of the water dispersible granule formulation is provided. The composition of water dispersible granule comprises pyrazole derivative and triazolopyrimidine sulfonamide as active ingredients, surfactant, binder, disintegrant and carrier. Other formulation additives such as pH adjuster and colorant may be additionally used.

A method for preparing the water dispersible granule formulation of the present invention is also provided. The water dispersible granule formulation can be prepared by mixing the active ingredients, surfactant, binder, disintegrant and carrier. Usually the active ingredients, surfactant, binder, disintegrant, carrier and other formulation additives are mixed uniformly in a mixer and milled by a mill such as an air jet mill to median diameter 5 to 50 micrometer. The milled mixture is kneaded by adding 2 to 10 % of water, extruded and dried. Other granulation method such as spray dry may be used. In this case, the milled mixture is well mixed with enough amount of water to get slurry.

In yet another embodiment of the present invention, the composition of the suspension concentrate formulation is provided. The composition of suspension concentrate comprises pyrazole derivative and triazolopyrimidine sulfonamide as active ingredients, surfactant, thickener, preservative, anti-freezing agent and water. Other formulation additives such as defoamer, pH adjuster and colorant may be additionally used.

A method for preparing the suspension concentrate formulation of the present invention is also provided. The suspension concentrate formulation can be prepared by wet milling of the active ingredients mixed with surfactant, water and other formulation additives. Usually the active ingredients, surfactant and anti-freezing agent are mixed by dissolving or dispersing in water. The mixture is preliminary milled by a homogenizer such as a colloid mill and then milled by a bead mill till median diameter reaches to 1 to 10 micrometer. Defoamer may be used during milling. After the milling, aqueous solution of thickener containing preservative is added.

Example: Water dispersible granule (WG)
Composition of Pyroxasulfone 63.8% + Diclosulam 10.0 % WG
Pyroxasulfone technical 63.8 w/w% (as a.i.)
Diclosulam technical 10.0 (as a.i.)
Sodium lignosulfonate 8.0
Sodium naphthalenesulfonate 2.0
Sodium dioctylsulfosuccinate 2.0
Polyvinyl alcohol 1.0
Clay 13.2 (Balance)
Total 100.0 w/w%

Composition of Pyroxasulfone 63.8% + Diclosulam 13.0 % WG
Pyroxasulfone technical 63.8 w/w% (as a.i.)
Diclosulam technical 13.0 (as a.i.)
Sodium lignosulfonate 8.0
Sodium naphthalenesulfonate 2.0
Sodium dioctylsulfosuccinate 2.0
Polyvinyl alcohol 1.0
Clay 10.2 (Balance)
Total 100.0 w/w%
The active ingredients pyroxasulfone technical, diclosulam technical, sodium lignosulfonate, sodium naphthalenesulfonate, sodium dioctylsulfosuccinate polyvinyl alcohol and clay are mixed and pulverized in a high speed mixer. The resulting mixture is kneaded with water, extruded through a screen (0.8 mm diameter opening) and dried.

The compositions or formulation according to the present invention are effective as PPI (pre-plant incorporation) and pre-emergence control of numerous monocotyledonous and dicotyledonous weeds in different crops.

The composition or formulation according to the present invention has a reduced or zero phytotoxicity with respect to important agricultural crops. This results in the present invention effective and possible in the selective control of weeds.

For practical use in agriculture, the composition or formulation of the present invention can be applied in such quantities as to guarantee applicative dosages of the synergistic mixture.

The term “herbicide” is used herein to mean an active ingredient that kills controls or otherwise adversely modifies the growth of plants. An herbicidal effective or vegetation controlling amount is an amount of 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.

It has been found that the combination of Pyroxasulfone and Diclosulam provides synergies in controlling weeds of soybean and also contributes in Herbicide Resistance Management (HRM) for sustainability of the life of this chemistry.

Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, from the foregoing description, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

Accordingly, it is not intended that the scope of the foregoing description be limited to the description set forth above, but rather that such description be construed as encompassing all of the features of patentable novelty that reside in the present invention, including all the features and embodiments that would be treated as equivalents thereof by those skilled in the relevant art. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above but should be determined only by a fair reading of complete specification to follow.

Following test results illustrate the present invention and not intended to limit the present invention.

Effect of Pyroxasulfone 63.8% + Diclosulam 13.0 % WG on the weed flora of soybean.

Soybean is a major cash crop grown globally as well as in India. Weeds are one of the main pest which damages soybean crop yields as high as 50-70%. Soybean crop is infested with grasses, broad leaf weeds and sedges. A lot of herbicide molecules are available in the market to control weeds of soybean. Some of these are Pendimethalin 30 % EC, Quizalofop-p-ethyl 5 % EC, Propaquizafop 10 % EC, Imazethapyr 10 % SL, Propaquizafop 2.5 % + Imazethapyr 3.75 % ME etc. Among the herbicides, Imazethapyr 10% SL is the highest selling herbicide on soybean. But none of the solo herbicide is able to control all type of weeds of soybean.

To overcome this situation, private as well as government institutions are working on combination development to increase efficacy and to obtain broader weed spectrum control. On the similar line, we have also tested few combinations of Pyroxasulfone 63.8% + Diclosulam 13.0 % WG and Pyroxasulfone 63.8% + Diclosulam 10.0 % WG, are suitable to control more number of weeds of soybean as compared to solo application of both molecules.
We had conducted trials to observe the synergy of combination and any type of detrimental effect on crop health. We found that combination of Pyroxasulfone 63.8% + Diclosulam 13.0 % WG @ 153.5g a.i./ha is found to be the best combination over existing solo herbicides as well as combination herbicides to control weeds of soybean and this combination outperforms the results of solo products Pyroxasulfone and Diclosulam. Results on the synergistic effect are discussed below.

Method:

Field experiments have been carried out involving the combination at various proportions to determine the efficacy, synergistic action and its residuality. Propaquizafop-p-ethyl plus Imazethapyr combination herbicide have been taken for comparison. Conventional herbicide like Pendimethalin has been chosen to determine the cost benefit ratio of the proposed combination.

Field Study:

Two field experiments were conducted at Anvi village of Aurangabad district in Maharashtra and at Onkarpura village of Kota district in Rajasthan during kharif 2016’ to evaluate the efficacy of Pyroxasulfone and Diclosulam and its combination, along with Pendimethalin and other combination having Propaquizafop p ethyl and Imazethapyr, were used for comparison in soybean. The experiments were carried out with variety JS 9305 in plots having 5m x 4m size in randomized block design with 7 treatments and replicated thrice. Pre-emergence herbicide application was done on 1 day after sowing and early post emergence treatment was done around 20 days after sowing. The target weeds of soybean viz., Echinochloa colonum, Dinebra retroflexa, Commelina communis, Digera arvensis, Phylanthis niruri, Ageratum conyzoides and Amaranthus viridis were counted to determine the efficacy of the products. Bio-efficacy, in terms of species wise weed count, total weed count and total dry weed weight were taken up.

Validations for Inventions Concepts:

The above mentioned field studies were undertaken with the following objectives.

? To determine the effective dose of herbicides combination on the weed flora of soybean.
? To establish the synergistic action in terms of increased efficacy and broad weed spectrum control over the single application of both herbicide.
? Compatibility of the formulations in terms of physical appearance of mixture solution, safety to crop plants, spray operator etc.

A. Effective Dose:-

Two trials were conducted to observe the efficacy of different herbicides on major weeds of soybean. Major weeds were Echinochloa colonum, Dinebra retroflexa, Commelina communis, Digera arvensis, Phylanthis niruri, Ageratum conyzoides and Amaranthus viridis. Bio-efficacy, in terms of species wise weed count, total weed count and total dry weed weight are presented in Table1.1 and Table 2.1. It is revealed from tables that the best treatment was ready mix combination of Pyroxasulfone 63.8% + Diclosulam 13.0 % WG @153.5g a.i./ha had good efficacy on both grasses and broad leaf weeds as compared to solo application of Pyroxasulfone 85% WG @127.5 g a.i./ha; Diclosulam 84 %WG@ 26 g a.i./ha; Pendimethalin 30% EC @ 1000 g a.i./ha and combination product of Propaquizafop 2.5 % + Imazethapyr 3.75 % ME@125 g a.i./ha.

Least total weed count of (4.0/m2 and 3.7/ m2) respectively at both locations was observed with Pyroxasulfone 63.8% + Diclosulam 13.0 % WG as compared to all other treatments including control having a total weed count of (38.7 and 33.7/m2) respectively at both locations.

B. Establishment of synergistic action:

Extensive literatures survey and more number of trials revealed that the herbicide of different groups at a reduced rate will have synergistic effect than additive or deleterious effect. Based on the literature available, combinations of herbicides have been developed and globally used on to combat on many weeds. Such combinations also provides enhanced spectrum of activity and avoid resistance development for longer period.
Present study also provides evidence on the synergistic effect of combination. Solo application of Diclosulam 84 % WG@ 26 g a.i./ha was working well on broad leaf weeds but not effective on grasses of soybean crop. While solo application of Pyroxasulfone 85 % WG@ 127.5 g a.i./ha was good on grasses but found moderate on broad leaf weeds . Similarly, other solo herbicides as Pendimethalin 30 % EC @ 1000 g a.i. /ha etc. are also not able to control all weeds of grasses and broad leaf weeds. Combination of Pyroxasulfone 63.8 % + Diclosulam 13 % WG 153.5g a.i./ha was found effective to control both grasses and broad leaf weeds with least weed count and higher yield, thus establishing synergism in term of broader weed spectrum coverage as well as higher efficacy.

C. Compatibility of combination: -

Physical observation on the treated plants involving either solo products or the combination does not affect the safety of the crop plants and provided the normal yield. It has been observed that no detrimental effect on the skin and eyes irritation to the spray operators either by combination or solo products (Table -1.4 & 2.4)

D. Yield data:

Yield data was also recorded and presented in Table-1.3 and Table-2.3. Highest yield was recorded in the combination involving 153.5g a.i./ha (Pyroxasulfone 63.8% + Diclosulam 13.0 % WG) which provided a yield of 12.9 q/ha and 13.8 q/ha at both trial locations respectively, followed by Pyroxasulfone 63.8% + Diclosulam 10.0 % WG @147.5 g a.i./ha (11.2 q/ha and 12.5 q/ha) and Propaquizafop p ethyl 2.5 % + Imazethapyr 3.75 % (10.3 q/ha and 11.0 q/ha). In the control, lowest yield was recorded (5.5 q/ha and 8.2 q/ha) at both the location respectively. It is evident from the table that the combination developed for the control of weeds of soybean gave good control on weeds and thereby increased the yield. Advantages to the end user customers for parameters like broaden the spectrum of activity for the control of grasses, sedges and broad leaf weeds.

Location: - 1

Location Detail : Anvi, Aurangabad, Maharastra

Season : Kharif, 2016

Date of sowing : 24/6/2016

Date of application (PE) : 25/06/2016 (1 DAS)

Date of application (PO) : 16/07/2016 (21 DAS)

Treatment detail: -

Sr.
No. Treatment Dose/ha Time of Application
Type Technical
g a.i. Formulation
(g or ml)
1. Pyroxasulfone 85% WG PE* 127.5 150 0-1 DAS***
2. Diclosulam 84% WG PE 26 31 -do-
3. Pendimethalin 30 % EC PE 1000 3300 -do-
4. Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 -do-
5. Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 -do-
6. Propaquizafop p ethyl 2.5 % + Imazethapyr 3.75 % w/w ME EPO** 125 2000 EPO (20 DAS)
7. Control - - - -

*PE – pre-emergence **EPO- Early post emergence ***DAS – Days after sowing

Table-1.1: - Bio-efficacy of different treatments on the weed flora of soybean.

Sr.no. Treatment Dose/ha Species wise Mean weed count/1 M2 (Avg. of 3 replication) 45 DAS Total weed count / m2 Total weed dry weight (g/ m2)
g a.i. g or ml Commelina
communis. Digera
arvensis Phylanthus
niruri Ageratum conyzoides Echinochloa colonum Dinebra retroflexa.
1 Pyroxasulfone 85% WG 127.5 150 6.0 (2.5) 0.3 (0.9) 5.7 (2.5) 4.0 (2.1) 0.7 (1.1) 0.7 (1.1) 17.3 (4.2) 2.2 (1.6)
2 Diclosulam 84 % WG 26 31 2.7 (1.8) 0.7 (1.1) 1.3 (1.3) 1.7 (1.5) 8.3 (3.0) 4.7 (2.3) 19.3 (4.5) 2.4 (1.7)
3 Pendimethalin 30 % EC 1000 3300 4.0 (2.1) 1.0 (1.2) 2.3 (1.7) 3.3 (2.0) 4.3 (2.2) 4.0 (2.1) 19.0 (4.4) 2.4 (1.7)
4 Pyroxasulfone 63.8% + Diclosulam 10.0 % WG 147.5 200 1.0 (1.6) 0.7 (1.1) 1.0 (1.2) 2.3 (1.7) 1.0 (1.2) 0.7 (1.1) 7.7 (2.9) 1.0 (1.2)
5 Pyroxasulfone 63.8% + Diclosulam 13.0 % WG 153.5 200 1.0 (1.2) 0.0(0.7) 0.3 (0.9) 1.3 (1.3) 0.7 (1.1) 0.7 (1.1) 4.0 (2.1) 0.5 (1.0)
6 Propaquizafop 2.5 % + Imazethapyr 3.75 % w/w ME 125 2000 3.7 (2.0) 2.0(1.6) 3.3 (2.0) 3.0 (1.9) 1.0 (1.2) 1.0 (1.2) 14.0 (3.8) 1.8 (1.5)
7 Control - - 8.0 (2.9) 6.0 (2.5) 6.0 (2.5) 4.3 (2.2) 9.0 (3.1) 5.3 (2.4) 38.7 (6.3) 4.8 (2.3)
CD (0.05%) - - 0.428 0.409 0.325 0.375 0.484 0.428 0.330 0.092
Figures in parenthesis are square root value

Table -1.2: - Impact of different treatments on yield.

S. no. Treatment Time of application Dose/ha Yield data
q/ha
g a.i. g or ml
1 Pyroxasulfone 85% WG PE* 127.5 150 9.6 (3.2)
2 Diclosulam 84 % WG PE 26 31 8.3 (3.0)
3 Pendimethalin 30 % EC PE 1000 3300 8.5 (3.0)
4 Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 11.2 (3.4)
5 Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 12.9 (3.7)
6 Propaquizafop 2.5 % + Imazethapyr 3.75 % w/w ME EPO** 125 2000 10.3 (3.3)
7 Control - - - 5.5 (2.5)
CD (0.05 %) 0.071

*PE- Pre-emergence **EPO- Early Post Emergence

Table – 1.3 Impact of different treatments on crop heath of soybean.

Sr.
No. Treatment Type Dose/ha Phytotoxicity (0-10 scale) in terms of yellowing, necrosis, wilting, epinasty, hyponasty etc.
g a.i. g or ml 1
DAS 3
DAS 5
7DAS 7
DAS 10
DAS
1. Pyroxasulfone 85% WG PE* 127.5 150 0 0 0 0 0
2. Diclosulam 84 % WG PE 26 31 0 0 0 0 0
3. Pendimethalin 30 % EC PE 1000 3000 0 0 0 0 0
4. Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 0 0 0 0 0
5. Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 0 0 0 0 0
6. Propaquizafop 2.5 % + Imazethapyr 3.75 %
w/w ME EPO** 125 2000 0 0 0 0 0
7. Control - - - 0 0 0 0 0

*PE- Pre-emergence **EPO- Early Post Emergence

Location - 2

Location Detail : Onkarpura, Kota, Rajasthan

Date of sowing : 20/6/2016

Date of application (PE) : 21/06/2016 (1 DAS)

Date of application (PO) : 12/07/2016 (22 DAS)

Treatment detail: -
Sr.
No. Treatment Dose/ha Time of Application
Type Technical
g a.i. Formulation
(g or ml)
1. Pyroxasulfone 85% WG PE* 127.5 150 0-1 DAS***
2. Diclosulam 84% WG PE 26 31 -do-
3. Pendimethalin 30 % EC PE 1000 3300 -do-
4. Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 -do-
5. Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 -do-
6. Propaquizafop p ethyl 2.5 % + Imazethapyr 3.75 % EPO** 125 2000 EPO (20 DAS)
7. Control - - - -

*PE – pre-emergence **EPO- Early post emergence ***DAS – Days after sowing

Table-2.1: - Bio-efficacy of different treatments on the weed flora of soybean.

s. no. Treatment Dose/ha Species wise Mean weed count/1 M2 (Avg. of 3 replication) 45 DAS Total weed count / M2 Total weed dry weight (g/ M2)
g a.i. g or ml Commelina
communis. Digera
Arvensis Phylanthus
niruri Trianthema portulacastrum Echinochloa
colonum
1 Pyroxasulfone 85% WG 127.5 150 4.7 (2.3) 3.7 (2.0) 2.3 (1.7) 3.3 (2.0) 1.0 (1.2) 15.0 (3.9) 1.6 (1.4)
2 Diclosulam 84 % WG 26 31 1.3 (1.4) 1.0 (1.2) 0.7 (1.1) 1.7 (1.5) 8.3 (3.0) 13.0 (3.7) 1.4 (1.4)
3 Pendimethalin 30 % EC 1000 3300 4.3 (2.2) 3.7 (2.0) 2.3 (1.7) 2.7 (1.8) 8.4 (3.0) 21.4 (4.7) 1.8 (1.5)
4 Pyroxasulfone 63.8% + Diclosulam 10.0 % WG 147.5 200 2.3 (1.7) 1.3 (1.4) 1.3 (1.4) 2.3 (1.7) 1.0 (1.2) 8.3 (3.0) 0.7 (1.1)
5 Pyroxasulfone 63.8% + Diclosulam 13.0 % WG 153.5 200 1.0 (1.2) 0.3 (0.9) 0.3 (0.9) 1.3 (1.4) 0.7 (1.1) 3.7 (2.0) 0.5 (1.0)
6 Propaquizafop 2.5 % + Imazethapyr 3.75 % w/w ME 125 2000 3.3 (2.0) 1.7 (1.5) 1.3 (1.4) 2.3 (1.7) 1.7 (1.5) 10.3 (3.3) 1.7 (1.5)
7 Control - - 7.0 (2.7) 9.0 (3.1) 3.3 (2.0) 3.0 (1.9) 11.3 (3.4) 33.7 (5.8) 3.5 (2.0)
CD (0.05%) - - 0.248 0.296 0.362 0.339 0.370 0.352 0.107

Figures in parenthesis are square root value

Table -2.2: - Impact of different treatments on yield.

S. no. Treatment Time of application Dose/ha Yield data
q/ha
g a.i. g or ml
1 Pyroxasulfone 85% WG PE* 127.5 150 10.0 (3.2)
2 Diclosulam 84 % WG PE 26 31 10.2 (3.3)
3 Pendimethalin 30 % EC PE 1000 3300 9.6 (3.2)
4 Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 12.5 (3.6)
5 Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 13.8 (3.8)
6 Propaquizafop 2.5 % + Imazethapyr 3.75 % w/w ME EPO** 125 2000 11.0 (3.4)
7 Control - - - 8.2 (2.9)
CD (0.05 %) - - - 0.095

*PE – pre-Emergence ** EPO – Early Post Emergence

Table – 2.3 Evaluation of the impact of different molecule on crop heath of soybean.

Sr.
No. Treatment Type Dose/ha Phytotoxicity (0-10 scale) in terms of yellowing, necrosis, wilting, epinasty, hyponasty etc.
g a.i.ss g or ml 1
DAS 3
DAS 5
7DAS 7
DAS 10
DAS
1. Pyroxasulfone 85% WG PE* 127.5 150 0 0 0 0 0
2. Diclosulam 84 % WG PE 26 31 0 0 0 0 0
3. Pendimethalin 30 % EC PE 1000 3000 0 0 0 0 0
4. Pyroxasulfone 63.8% + Diclosulam 10.0 % WG PE 147.5 200 0 0 0 0 0
5. Pyroxasulfone 63.8% + Diclosulam 13.0 % WG PE 153.5 200 0 0 0 0 0
6. Propaquizafop 2.5 % + Imazethapyr 3.75 %
w/w ME EPO** 125 2000 0 0 0 0 0
7. Control - - - 0 0 0 0 0
*PE- Pre-emergence **EPO- Early Post Emergence

WE CLAIM:

1. A stable synergistic herbicidal composition for management of weeds comprising a herbicidal pyrazole derivative as a first component (a) and at least one co-herbicide selected from a range of co-herbicides as a second component (b), and agriculturally acceptable formulation additives (c), wherein weight percentage of (a) is 8.5 to 80% and 25 to 76%, weight percentage of (b) is 1.5 to 15% and 5 to 14% and weight percentage of (c) is 5 to 90% and 10 to 70%.

2. The composition as claimed in claim 1, wherein the preferred component (a) is pyroxasulfone, i.e. 3-[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole.

3. The composition as claimed in claim 1, wherein the component (b) is selected from the group consisting of triazolopyrimidine sulfonamides including, not being limited to, diclosulam, cloransulam-methyl, florasulam, flumetsulam, metosulam, penoxsulam, and pyroxsulam or an agriculturally acceptable salt, carboxylic acid, carboxylate salt, or ester thereof.

4. The composition as claimed in claim 1 to 3, wherein the preferred component (b) is diclosulam.

5. The composition as claimed in claim 1, wherein (c) is selected from at least one organic or inorganic carrier material including agriculturally acceptable formulation additives such as surfactant, solid carrier, liquid carrier, binder, disintegrate, pH adjuster, thickener, preservative, anti-freezing agent, defoamers and coloring agent, or a combination thereof.

6. The composition as claimed in claim 5, wherein suitable surfactants include sugar esters (such as sorbitan monolaurate, polyoxyethylene sorbitan monolaurrate), polyoxyethylene alkyl ethers (such as polyoxyethylene lauryl ether or polyoxyethylene coconut fatty alcohol ether), polyoxyethylene aryl ethers (such as polyoxyethylene nonylphenyl ether or polyoxyethylene trystyrylphenyl ether), polyoxyethylene vegetable oil ethers (such as polyoxyethylene castor oil), polyoxyethylene fatty acid esters (such as polyoxyethylene monolaurate), polyoxyethylene polyoxypropylene block co-polymers, polyoxyethylene polyoxypropylene alkyl ether (such as polyoxyethylene polyoxypropylene lauryl ether), polyoxyethylene alkyl amines (such as polyoxyethylene stearyl fatty amine), alkyl sulfates (such as sodium lauryl sulfate), polyoxyethylene alkyl ether sulfates (such as sodium polyoxyethylene lauryl ether sulfate), polyoxyethylene aryl ether sulfates (such as sodium polyoxyethylene nonylphenyl ether sulfate or ammonium polyoxyethylene tristyrylphenyl ether sulfate), alkane sulfonates (such as sodium dodecyl sulfonate), ‘alpha’-olefin sulfonate, aryl sulfonates (such as sodium dodecylbenzene sulfonate, sodium naphthalene sulfonate sodium alkylnaphthalene sulfonate, sodium naphthalene sulfonate formaldehyde condensate or sodium alkyl diphenyl ether sulfonate), alkylsulfosuccinates (such as sodium dioctylsulfosuccinate), sodium lignosulfonates polyoxyethylene alkyl ether phosphate, polyoxyethylene aryl ether phosphates (such as polyoxyethylene phenyl ether phosphate) and polyoxyethylene polyoxypropylene block co-polymer phosphate or a combination thereof.

7. The composition as claimed in claim 5, wherein suitable liquid carriers include water, alcohols (such as ethanol, propanol, isopropanol ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol, glycerin), polyol ether (such as ethylene glycol monopropyl ether, diethylene glycol monomethyl ether), ketones (such as methyl isobutyl ketone, cyclohexanone), ethers (such as dipropyl ether, dioxane, ethylene glycol monoethyl ether, tetrahydrofuran, dipropylene glycol dimethyl ether), aliphatic hydrocarbons (such as normal paraffin, naphthene, isoparaffin, kerosene, mineral oil), aromatic hydrocarbons (such as xylene, solvent naphtha, alkyl naphthalene), esters (such as ethyl acetate, diisopropyl phthalate, dimethyl adipate), lactones (such as gamma-butyrolactone), amides (such as dimethylformamide, N-methylpyrrolidone, N,N-dimethyldecanamide), nitriles (such as acetonitrile), sulfur compounds (such as dimethyl sulfoxide) and vegetable oils (such as soybean oil, rapeseed oil, cotton seed oil). These liquid carriers may be used alone or in a combination of two or more kinds or a combination thereof.

8. The composition as claimed in claim 5, wherein suitable solid carriers include natural minerals (such as talc, kaolinite, pyrophyllite, montmorillonite, attapulgite, bentonite, calcite, diatomaceous earth), synthetic minerals (such as precipitated silica, fumed silica and calcium carbonate), inorganic salts (such as calcium carbonate, ammonium sulfate, sodium sulfate, potassium chloride) and organic materials (such as urea, lactose, starch, cellulose, plant powders). These solid carriers may be used alone or in a combination of two or more kinds or a combination thereof.

9. The composition as claimed in claim 5, wherein suitable binders include polyvinyl alcohol, dextrin, denatured dextrin, soluble starch, carboxymethyl cellulose and bentonite or a combination thereof.
10. The composition as claimed in claim 5, wherein suitable disintegrants include sodium tripolyphosphate, sodium hexametaphosphate, carboxymethyl cellulose, sodium polycarbonate and bentonite or a combination thereof.

11. The composition as claimed in claim 5, wherein suitable pH adjusters include sodium or potassium carbonate, sodium or potassium hydrogen carbonate, sodium or potassium dihydrogenphosphate, disodium or dipotassium hydrogenphosphate, citric acid, malic acid and triethanolamine or a combination thereof.

12. The composition as claimed in claim 5, wherein suitable thickeners includes xanthan gum, welan gum, guar gum, polyvinyl alcohol, carboxymethyl cellulose and its salt, silica and bentonite or a combination thereof.

13. The composition as claimed in claim 5, wherein suitable preservatives include 4-hydroxybenzoic acid esters, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-one or a combination thereof.

14. The composition as claimed in claim 5, wherein suitable anti-freezing agents include glycerin, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and urea or a combination thereof.

15. The composition as claimed in claim 5, wherein suitable defoamers include silicone compounds and organic fluorine compounds or a combination thereof.

16. The composition as claimed in claim 5, wherein suitable coloring agents include organic dyestuffs (such as azo dye, phthalocyanine dye or alizarin dye) and inorganic pigments (such as iron oxide) or a combination thereof.

17. A method for the preparation of a stable synergistic herbicidal composition as claimed in claim 1 comprising an herbicidal pyrazole derivative as a first component (a) and at least one co-herbicide selected from a range of co-herbicides as a second component (b), and agriculturally acceptable formulation additives (c).