Description:HERBICIDAL COMPOSITION
FIELD OF INVENTION
The present invention relates to a broad-spectrum herbicidal composition for post emergence control of weeds in cotton crops.
BACKGROUND OF THE INVENTION
Weed control is an important practice for crops growth. The losses caused by weeds in agricultural production environments include reduced crop quality, increased irrigation costs, increased harvesting costs, reduced land value, injury to livestock and crop damage from insects and pests harbored by the weeds. Further, weeds may compete with crop plants for the essential nutrients and may produce toxic or irritant chemicals that cause human or animal health problems. Some of the weed varieties also produce immense quantities of seed or vegetative reproductive parts or both that contaminate agricultural products and perpetuate the species in agricultural land.

The weed menace is more amplified in cotton due to various reasons like it is grown under both rainfed and irrigated conditions, conducive for heavy weed infestation, wider spacing in crops, higher level of fertilization (HYV/Hybrids), slow growth in early stages (weed takes about 8 weeks to reach maximum cover due to its quick growth, while cotton takes at least 16 weeks to cover 90% space).

Hence there is an ever growing need to develop herbicidal active ingredient combinations that not only provide satisfactory control of weeds in cotton fields but also are non-phytotoxic to the treated crops. It must however be appreciated that the process of combining the individual active ingredients or formulating one or more herbicides in a single composition poses many challenges to the formulator. Major challenges being stability of the co- formulation, decomposition of an active compound, or antagonism of the active compounds, phytotoxicity in the treated crops. Therefore, the process of co-formulating the active ingredients requires rigorous experimentation.

Clethodim (IUPAC name : 2-[(E)-N-[(E)-3-chloroprop-2-enoxy]-C-ethylcarbonimidoyl]-5-(2-ethylsulfanylpropyl)-3-hydroxycyclohex-2-en-1-one) is a member of the cyclohexanedione family of herbicides. It is a systemic herbicide, rapidly absorbed and readily translocated from treated foliage to the root system and growing parts of the plant. It is used for the post emergence control of annual and perennial grass weeds in broad leaved crops including soybeans, cotton, sunflowers, etc. It is a fatty acid synthesis inhibitor and works by inhibition of acetyl CoA carboxylase (ACCase).

Pyrithiobac sodium (IUPAC name: sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate is used for post emergence control of broad-leaved weeds including Ipomoea, Xanthium and Amaranthus spp. In cotton and pre-emergence control of broad-leaved weeds including Amaranthus spp., Sida spinosa and Abutilon theophrasti. It is a branched chain amino acid synthesis inhibitor and selectivity is based on differing rates of metabolism.

Martin-Duvall et al. reported a study for testing the efficacy of grass herbicides on barnyardgrass (Echinochloa crus-galli) when applied alone and in combination with staple (pyrithiobac sodium). The study was conducted at San Joaquin Valley of California to determine the effects of Staple (Pyrithiobac sodium) with Fusilade (fluazifop), Poast (sethoxydim), and Prism (clethodim) in which the grass herbicides are either tank mixed with or applied after the Staple application. However, the study does not talk about a ready to use composition that is synergistic.

Even though the above mentioned herbicidal active ingredients are individually known and there have been studies relating to tank mixtures of these herbicides, there is still a need to develop a stable ready to use composition comprising Clethodim and Pyrithiobac sodium, as active ingredients which at specific weight percentages results in broad-spectrum control of obnoxious weeds, particularly in cotton crop without any noticeable phytotoxicity.

OBJECT OF THE INVENTION
It is an object of the present invention to provide a novel, synergistic, broad spectrum herbicidal composition comprising Clethodim and Pyrithiobac sodium for effectively controlling broad-leaved weeds and narrow leaved weeds in cotton.
It is another object of the present invention to provide a novel, synergistic, broad spectrum herbicidal composition comprising Clethodim and Pyrithiobac sodium for effectively controlling broad-leaved weeds and narrow leaved weeds in cotton, wherein said herbicidal composition additionally comprises vegetable oil.

It is yet another object of the present invention to provide a herbicidal composition for effectively controlling broad-leaved weeds and narrow leaved weeds in cotton, wherein said herbicidal composition is safe for cotton crop.

It is yet another object of the present invention to provide a process for preparing a microemulsion concentrate comprising Clethodim, Pyrithiobac sodium along with at least one co-solvent, at least one emulsifier and at least one spreader.

It is yet another object of the present invention to provide a process for preparing a microemulsion concentrate comprising Clethodim, Pyrithiobac sodium and vegetable oil along with at least one co-solvent, at least one emulsifier and at least one spreader.

SUMMARY OF THE INVENTION
In an aspect of the present invention, there is provided a herbicidal composition for effectively controlling broad-leaved weeds and narrow leaved weeds in cotton.
In another aspect of the present invention, there is provided a ready to use herbicidal composition comprising Clethodim and Pyrithiobac sodium along with at least one agriculturally acceptable excipient.
In yet another aspect of the present invention there is provided a ready to use herbicidal composition comprising Clethodim, Pyrithiobac sodium and vegetable oil along with at least one agriculturally acceptable excipient.
In yet another aspect of the present invention, there is provided a process for preparing a microemulsion concentrate comprising Clethodim, Pyrithiobac sodium as active ingredients along with at least one co-solvent, at least one emulsifier and at least one spreader.
In yet another aspect of the present invention, there is provided a method of controlling undesired vegetation in cotton crop, said method comprising applying at the locus of the undesired vegetation, a herbicidally effective amount of the herbicidal composition of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Those skilled in the art will be aware that the invention described herein is subject to variations and modifications other than those specifically described. It is to be understood that the invention described herein includes all such variations and modifications. The invention also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and all compositions of any two or more of said steps or features.
The instant invention does not use any biological material originating in India. Vegetable oil, that may be used in the instant invention is not obtained from India and was procured from an imported source (ie.)
Abbreviations

D.M.

Demineralized Water
RTU Ready to Use
MEC Micro emulsion concentrate
QS Quantum satis
A.I/ a.i Active Ingredients
DAA Days After Application
a.i/ha Dosage of active ingredient per hectare
Unless otherwise specified, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of the ordinary skill in the art to which the invention belongs. For further guidance, term definitions may be included to better appreciate the teaching of the present invention.
As used herein, the term “plant” refers to any plant or part thereof including serial and subterranean parts of the plant. It is contemplated that the parts of the plant may be, for example, flowers, fruits or vegetables, shoots, leaves, needles, stalks, stems, fruiting bodies, seeds, also roots and that parts of the plants may or may not be attached to the remainder of the plant.
As used herein, the term “weed” refers to the unwanted plant which competes for resources with the crop or plant of interest.
As used herein, the term “herbicide” refers to a substance which adversely affects the existence and growth of the target weed.
As used herein the term “herbicidally effective amount” is that quantity of the herbicide active ingredient, applied in an amount which will provide the required control of weed on commercial crops. The amount is dependent upon many factors including, for example, type of formulations, the crop, weed sought to be controlled and environmental conditions.
As used herein, the term “agriculturally acceptable excipient” refers to an ingredient, additive, component or supplement, liquid or solid, suitable for incorporation in agricultural compositions.
As used herein, the terms “comprise”, “comprises”, “comprising”, “include”, “includes”, and “including” are meant to be non-limiting ie. other steps and other ingredients which do not affect the end of result can be added. The above terms encompass the terms “consisting of” and “consisting essentially of”.
The terms “weight percent”, “wt-%”, “percent by weight”, “% by weight” and variations thereof, as used herein, refer to the concentration of a substance as the weight of that substance divided by the total weight of the composition and
multiplied by 100. It is understood that, as used here, “percent “, “%” and the like are intended to be synonymous with “weight percent”, “wt %”, etc.
In an embodiment, the present invention provides a herbicidal composition comprising 1) Clethodim 2) Pyrithiobac sodium and at least one agriculturally acceptable excipient.
In an embodiment, the present invention provides a herbicidal composition comprising Clethodim in an amount ranging from 5-25% w/w, Pyrithiobac sodium is an amount ranging from 1-12% w/w and at least one agriculturally acceptable excipient or adjuvant in suitable amounts.
In a preferred embodiment, the present invention provides a herbicidal composition comprising 11.5% clethodim, 6% Pyrithiobac sodium, 16% solvent, 36 % emulsifier, 1% spreader and QS demineralised water.
In a particular embodiment, the present invention provides a herbicidal composition which is ready to use. A ready to use formulation or composition has various advantages over the tank mixtures of herbicides. The ready to use formulations generally have lesser or no inhalation hazards, easy handling, low chances of sedimentation, are environmentally safer, show good efficacy without phytotoxicity and lower transportation costs. Besides, it is a known fact that a ready to use herbicidal composition is based on scientific practices as the formulation is prepared after stability and compatibility studies.
In an embodiment, the present invention provides a herbicidal composition that further additionally comprises vegetable oil. In an embodiment, the vegetable oil is selected from the group comprising castor oil, mustard oil, cotton seed oil, soya bean oil, ground nut oil, sunflower oil and neem seed oil. In an embodiment, the vegetable oil is present in an amount ranging from 0.05-10% w/w.
Addition of vegetable oil offers several advantages like biodegradability, reduced run off, selective weed control, improved adhesion and penetration and synergistic effect to the herbicidal composition.

The vegetable oil was procured from 4825 Jalan Permatang Pauh, 13400 Butterworth, P.W. Malaysia. The present invention does not use any biological material obtained from India.

In an embodiment, the agriculturally acceptable excipient or adjuvants is selected from the group comprising a solvent, an emulsifier, a spreader, and demineralised water.

In an embodiment, the solvent is selected from the group comprising xylene, mixture of aromatic hydrocarbon solvents, cyclohexanone, N- Methyl Pyrrolidone, Dimethyl Sulfoxide, Dimethyl Formamide, N- Butyl Alcohol. In a preferred embodiment, the solvent is N- Methyl Pyrrolidone. In an embodiment, said solvent is present in an amount ranging from 10-30% w/w.

In an embodiment, the emulsifier is selected from the group comprising calcium benzene dodecyl benzene, linear alkyl benzene sulphonate, tristyrylphenol ethylene oxide derivative 1 mol to 30 mol. In a preferred embodiment, the emulsifier is tristyrylphenol ethylene. In an embodiment, the emulsifier is present in an amount ranging from 15-52% w/w.
In an embodiment, the spreader is selected from the group comprising dioctyl sulphosuccinate, polydimethyl siloxane. In a preferred embodiment, the spreader is dioctyl sulphosuccinate. In an embodiment, the spreader is present in an amount ranging from 0.2-5% w/w.
In an embodiment, demineralised water is present in an amount ranging from 20-40% w/w.
In an embodiment, the present herbicidal composition is effective in controlling both narrow leaved weeds and broad-leaved weeds in cotton crop. The broad-leaved weeds include Amaranthus viridis, Chenopodium album, Commelina benghalensis, Euphorbia hirta and others. The narrow leaved weeds include Cynodon dactylon, Echinocloa crusgalli and Dactyloctenium aegypticum.
The presently disclosed herbicidal composition is effective in controlling a variety of weeds including but not limited to Echinochloa colonum (narrow leaved), Setaria glauca (narrow leaved), Digiteria arvensis (broad leaved), Amaranthus viridis (broad leaved), Parthenium spp. and Acalypha spp.
In an embodiment, the herbicidal composition of the present invention is formulated as a micro-emulsion (ME), Suspension concentrates (SC), oil-based suspension concentrates (OD) and suspo-emulsion (SE).
It is known fact that conventional systems, pesticidal powders, emulsifiable concentrates (ECs), oil in water emulsions (O/W emulsions), water in oil emulsions (W/O emulsions), aqueous suspension concentrates etc. are popularly used pesticide formulations.
In a preferred embodiment, the presently disclosed herbicidal composition is formulated as a micro -emulsion. Microemulsion systems are preferred for their long-term thermodynamic stability, low viscosity, cost economy, and aesthetic appeal. Such systems provide a method for preparing an isotropic mixture of oil and water.
Major advantage of microemulsion is in the usage of a widely used, easily available, environmentally friendly and least expensive diluents, water.
However, it must be noted that the formulation of pesticide microemulsion is a difficult task. Micro emulsions are water-based formulations with a very small, emulsified droplet size which makes the formulation transparent.
Microemulsions are also thermodynamically stable over a wide temperature range due to this very fine droplet size, usually between 0.01 and 0.05 µm. Therefore, in contrast to other emulsion systems, where the oil droplets can slowly coalesce causing phase separation, this does not occur in the micro-emulsion formulations.
Thus, the major advantages of microemulsion are given below:
1. Thermodynamically stable leading to increased shelf life
2. Low solvent level
3. Easy to transport and store.
4. High flash point and safe handling
5. Improved bioefficacy due to the solubilisation of active ingredient in the micro droplets
6. Low viscosity and easier to handle.
In an embodiment, the present invention provides a process for preparing a micro emulsion concentrate comprising the following steps:
1. Solvent was taken in the required amount.
2. Pyrithiobac sodium technical & Clethodim technical were added and dissolved properly.
3. Emulsifier and spreader were added and mixed properly.
4. Water was added, and the mixture was stirred until it converted into a clear homogenous liquid.
In an embodiment, the present invention provides a herbicidal composition comprising clethodim in an amount ranging from 5-25% w/w, Pyrithiobac sodium is an amount ranging from 1-12% w/w and at least one agriculturally acceptable excipient or adjuvant in suitable amounts.
In a preferred embodiment, the present invention provides a herbicidal composition comprising 11.5% clethodim, 6% Pyrithiobac sodium, 16% solvent, 36 % emulsifier, 1% spreader and QS demineralised water.
In an embodiment, the solvent is selected from the group comprising xylene, mixture of aromatic hydrocarbon solvents, cyclohexanone, N- Methyl Pyrrolidone, Dimethyl Sulfoxide, Dimethyl Formamide, N- Butyl Alcohol. In a preferred embodiment, the solvent is N- Methyl Pyrrolidone. In an embodiment, said solvent is present in an amount ranging from 10-30% w/w.
In an embodiment, the emulsifier is selected from the group comprising calcium benzene dodecyl benzene, linear alkyl benzene sulphonate, tristyrylphenol ethylene oxide derivative 1 mol to 30 mol. In a preferred embodiment, the emulsifier is tristyrylphenol ethylene. In an embodiment, the emulsifier is present in an amount ranging from 15-52% w/w.
In an embodiment, the spreader is selected from the group comprising dioctyl sulphosuccinate, polydimethyl siloxane. In a preferred embodiment, the spreader is dioctyl sulphosuccinate. In an embodiment, the spreader is present in an amount ranging from 0.2-5% w/w.
In an embodiment, demineralised water is present in an amount ranging from 20-40% w/w.
In yet another aspect, the present invention provides a method of controlling undesirable vegetation in cotton crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising a) herbicidally effective amount of clethodim b) herbicidally effective amount of Pyrithiobac sodium and suitable amounts of agriculturally acceptable excipients.
In yet another aspect, the present invention provides a method of controlling undesirable vegetation in cotton crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising 1) Clethodim in an amount ranging from 5-25% w/w 2) Pyrithiobac sodium is an amount ranging from 1-12% w/w and at least one agriculturally acceptable excipient or adjuvant in suitable amounts.
In yet another aspect, the present invention provides a method of controlling undesirable vegetation in cotton crop, said method comprising treating the locus at which the crop is growing or intended to be grown with a herbicidal composition comprising 1) Clethodim in an amount ranging from 5-25% w/w 2) Pyrithiobac sodium is an amount ranging from 1-12% w/w 3) Vegetable oil in an amount ranging from 0.05-10 % w/w and at least one agriculturally acceptable excipient or adjuvant in suitable amounts.
Surprisingly, it was observed by the present inventors that the presently disclosed herbicidal composition provides a broad-spectrum control of weeds at much lower dosage of active ingredient combination as compared to what is achieved when the active ingredients were applied alone. Further, it was observed that the application of the presently disclosed herbicidal composition not only achieves effective control of narrow leaved weeds, broad leaved weeds and sedges in cotton crop.
In an embodiment, the presently disclosed herbicidal composition exhibits synergistic effect in controlling narrow leaved weeds, broad leaved weeds and sedges in cotton crop.
In a preferred embodiment, the active ingredient dosage of Pyrithiobac sodium in the synergistic herbicidal composition is 60 g ai/ha and the active ingredient dosage of Clethodim in the herbicidal composition is 115 g ai/ha.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present invention. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present invention, and all such modifications are considered to be within the scope of the present invention.
EXAMPLES
The examples below are given solely for the purpose of illustration and are not to be construed as limitations of the present invention, as many variations thereof are possible without departing from the spirit and scope of the invention.

Example 1: Preparation of a Microemulsion concentrate of Pyrithiobac sodium and Clethodim
Table 1 below provides a tentative composition of the presently disclosed herbicidal composition as a microemulsion concentrate.
Table 1: Herbicidal composition (CH0610 MEC)
Ingredient Tentative percentage w/w
Pyrithiobac sodium technical (basis of 100%) 6.0
Clethodim technical 11.5
Co-solvent 16.0
Emulsifier 36.0
Spreader 1.0
DM water 29.5
Total 100

Preparation method of MEC formulation
The MEC formulation as described above in Table 1 was prepared by following the below steps:
Step 1: Solvent was taken in the required amount.
Step 2: Pyrithiobac sodium technical & Clethodim technical was added and dissolved properly.
Step 3: Emulsifier and spreader was added and mixed properly. This was followed by addition of vegetable oil in required amount.
Step 4: Water was added, and the mixture was stirred until it converted into a clear homogenous liquid.
Example 2: Field evaluation of the bioefficacy of the present herbicidal composition
Location/season/crop:
The presently disclosed herbicidal trimix i.e., CH0610 MEC was tested for its bioefficacy against narrow leaved weeds and broad- leaved weeds in cotton. The trial was conducted during the kharif season 2023 at Guntur, Andhra Pradesh on local variety of cotton.
Trial layout:
The plants were aligned in a plot size of 50 sqm., with the spacing of 45 cm between individual crop plants and the spacing of 20 cm between the rows. The trial was laid out in a randomized block design consisting of a total of 9 treatments in three replications.
Climatic conditions:
The trial was conducted at a temp. of 32? under 80% relative humidity with no winds.
Application:
The application of the herbicidal mix was carried out at post emergence stage 20 days after sowing and at 2-4 leaves stage of weed.
Measured quantity of the chemical was added to required volume of water at the rate of 375 lit. /ha for spray. The spray tank was filled with ½ the quantity of clean required volume of water and then the measured chemical (according to the dose) was added followed by the rest half quantity of water. The solution was stirred well before application. A knapsack sprayer fitted with boom along with flood jet nozzle was used to apply the herbicidal composition.

Table 2 below provides the treatment details:
Table 2: Treatment details
Treatments Product a.i/ha Dose/ha
T-1 Untreated
T-2 CH-0610 MEC 60 + 115 1000
T-3 CH-0611 MEC 60 + 115 + 10 1000
T-4 CH-0585 MEC 50 + 85 1000
T-5 CH-5851 MEC 50 + 85 + 10 1000
T-6 CH-0815 MEC 80 + 150 1000
T-7 CH-8151 MEC 80 + 150 +10 1000
T-8 Clethodim 25 EC 125 500
T-9 Pyrithiobac sodium 10 EC 62.5 625
Note:
CH-0610 MEC Pyrithiobac sodium 6% + Clethodim 11.5% MEC
CH-0611 MEC Pyrithiobac sodium 6% + Clethodim 11.5% + Vegetable oil 0.1% MEC
CH-0585 MEC Pyrithiobac sodium 5% + Clethodim 8.5 % MEC
CH-5851 MEC Pyrithiobac sodium 5% + Clethodim 8.5 % + Vegetable oil 0.1% MEC
CH-0815 MEC Pyrithiobac sodium 8% + Clethodim 15% MEC
CH-8151 MEC Pyrithiobac sodium 8% + Clethodim 15% + Vegetable oil 0.1% MEC

Example 2: Evaluation of bio efficacy of CH 0610 MEC against broad leaved and narrow leaved weeds
Weed count: A quadrate (0.5m × 0.5m) was placed at 3 randomly selected places in all the plots of the experimental field and the number of weed flora were counted uniformly at 14 Days and 28 days after application.
Weed control: The weed control was calculated based on no. of live weed flora at 14 Days and 28 days after application.

Percent weed control = WC – WT
…………. × 100
WC

Where WC= No. of weed in control plot
WT= No. of weed in treated plot
(A) Bio efficacy study
Table 3 (a): Effect of herbicidal treatment on weed density at 14 DAA
Treatments Product a.i./ha Dose/ha Echinochloa colonic % Control Digera arvensis % Control Amaranthus viridis % Control Setaria glauca % Control
T-1 Untreated 25 17 14 19
T-2 CH-0610 MEC 60 + 115 1000 3 88.00 2 88.24 0 100.00 3 84.21
T-3 CH-0611 MEC 60 + 115 + 10 1000 2 92.00 1.5 91.18 0 100.00 2.5 86.84
T-4 CH-0585 MEC 50 + 85 1000 9 64.00 4 76.47 1.5 89.29 5 73.68
T-5 CH-5851 MEC 50 + 85 + 10 1000 6 76.00 6 64.71 2 85.71 3.5 81.58
T-6 CH-0815 MEC 80 + 150 1000 2.4 90.40 3 82.35 0 100.00 2.3 87.89
T-7 CH-8151 MEC 80 + 150 +10 1000 2.1 91.60 2 88.24 1 92.86 1.5 92.11
T-8 Clethodim 25 EC 125 500 4 84.00 16 5.88 5 64.29 7 63.16
T-9 Pyrithiobac sodium 10 EC 62.5 625 8 68.00 6 64.71 3 78.57 5 73.68

Treatments Product a.i./ha dose/ha Echinochloa colonic % Control Digera arvensis % Control Amaranthus viridis % Control Setaria glauca % Control
T-1 Untreated 27 19 17 21
T-2 CH-0610 MEC 60 + 115 1000 4 85.19 3 84.21 2 88.24 4 80.95
T-3 CH-0611 MEC 60 + 115 + 10 1000 3 88.89 2.5 86.84 1.5 91.18 3.5 83.33
T-4 CH-0585 MEC 50 + 85 1000 11 59.26 5 73.68 3 82.35 6 71.43
T-5 CH-5851 MEC 50 + 85 + 10 1000 7 74.07 4.5 76.32 2 88.24 3.7 82.38
T-6 CH-0815 MEC 80 + 150 1000 3 88.89 2.5 86.84 1.5 91.18 2.5 88.10
T-7 CH-8151 MEC 80 + 150 +10 1000 2.5 90.74 2 89.47 1 94.12 2 90.48
T-8 Clethodim 25 EC 125 500 6 77.78 7 63.16 6 64.71 8 61.90
T-9 Pyrithiobac sodium 10 EC 62.5 625 7 74.07 4 78.95 4 76.47 6 71.43
Table 3 (b): Effect of herbicidal treatment on weed density at 28 DAA

Example 3: Evaluation of phytotoxicity
Visual observations were recorded at 3, 7 and 10 days after application (DAA) of testing products. The parameters were observed leaf injury on tip/surface, necrosis, vein clearing, epinasty, hyponasty and wilting. The score scale (1-10) followed for leaf injury on tips/surface is given.
Table 4: Phytotoxicity symptoms scoring and rating for leaf injury on tip/surface:
Leaf injury on tips/surface Rating
0-10% 1
11-20% 2
21-30% 3
31-40% 4
41-50% 5
51-60% 6
61-70% 7
71-80% 8
81-90% 9
91-100% 10

Table 5: Phytotoxicity studies
Necrosis Burning Stunting
Treatments Product a.i./ha Dose/ha 3 DAA 7 DAA 10 DAA 3 DAA 7 DAA 10 DAA 3 DAA 7 DAA 10 DAA
T-1 Untreated 0 0 0 0 0 0 0 0 0
T-2 CH-0610 MEC 60 + 115 1000 0 0 0 0 0 0 0 0 0
T-3 CH-0611 MEC 60 + 115 + 10 1000 0 0 0 0 0 0 0 0 0
T-4 CH-0585 MEC 50 + 85 1000 3 3 0 3 3 0 0 0 0
T-5 CH-5851 MEC 50 + 85 + 10 1000 0 0 0 0 0 0 0 0 0
T-6 CH-0815 MEC 80 + 150 1000 3 3 3 3 3 3 3 3 3
T-7 CH-8151 MEC 80 + 150 +10 1000 3 3 3 3 3 3 3 3 3
T-8 Clethodim 25 EC 125 500 0 0 0 0 0 0 0 0 0
T-9 Pyrithiobac sodium 10 EC 62.5 625 0 0 0 0 0 0 0 0 0

Results & Conclusion:
The experiment was laid out in farmers field near Guntur (Andhra Pradesh). The prominent grassy weed species in the weedy plot at the time of application were Echinochloa colonum and Setaria spp in the narrow leaved weeds category and Digitaria arvensis and Amaranthus viridis in the broad-leaved weeds category.
As can be seen in Table 3 (a) Clethodim 25 EC alone at a dosage of 125 g a.i./ha shows 84 % control of Echinochloa colonum (narrow leaved weeds) and merely 6% control of Digiteria arvensis (broad leaved weed). Pyrithiobac sodium 10 EC at a dosage of 62.5 g ai/ha shows a 68% control of Echinochloa colonum (narrow leaved weeds) and a 65% control of Digiteria arvensis (broad leaved weed). However, unexpectedly, and surprisingly the combination of Clethodim and Pyrithiobac sodium (coded as CH-0611 MEC) shows a 92% control of Echinochloa colonum (narrow leaved weeds) and 91% control of Digiteria arvensis (broad leaved weed), wherein the dosage of Clethodim is 115g ai/ha and dosage of Pyrithiobac sodium is 60 g ai/ha. Thus, a significantly higher efficacy is achieved at relatively lower dosage.
As can be seen in Table 3 (b) Clethodim 25 EC alone at a dosage of 125 g a.i./ha shows 65% control of Amaranthus viridus (broad-leaved weed) and 62% control of Setaria glauca (narrow leaved weeds). Pyrithiobac sodium 10 EC at a dosage of 62.5 g ai/ha shows a 76% control of Amaranthus viridus (broad-leaved weed) and 71% control of Setaria glauca (narrow leaved weeds). However, unexpectedly, and surprisingly the combination of Clethodim and Pyrithiobac sodium (coded as CH-0611 MEC) wherein the dosage of Clethodim is 115g ai/ha and dosage of Pyrithiobac sodium is 60 g ai/ha, shows a 91% control of Amaranthus viridus (broad-leaved weed) and 83% control of Setaria glauca (narrow leaved weeds). Thus, a significantly higher efficacy is achieved at relatively lower dosage.
Further, as seen in table 5 the phytotoxicity studies revealed that no phytotoxicity symptoms were observed for the combination (CH -0610 MEC and CH0611 MEC) at a dosage of 60g ai/ha of Pyrithiobac sodium and 115 g ai/ha dosage of Clethodim. However, it was seen that higher concentration of the combination (CH-0815 MEC) showed necrosis and some other phytotoxic symptoms on cotton crop.
Therefore, it may be safely concluded that application of the novel post-emergence herbicidal combination coded as CH-0610 comprising Pyrithiobac sodium 6% + Clethodim 11.5% MEC at an active ingredient dosage of 60 + 115 gm a.i. per hectare and herbicidal combination coded as CH-0611 MEC (with vegetable oil) at an active ingredient dosage of 60+115+10 gm provided effective control of both the narrow leaved weed and broad-leaved weeds without any phytotoxicity symptoms on Cotton crop. Moreover, this efficacy was achieved at a reduced dosage of the actives Clethodim and Pyrithiobac sodium, thus a synergistic effect exists for the herbicidal composition.
On the contrary, the solo products ie Clethodim 25EC (at an AI dosage of 125g/ha) and Pyrithiobac sodium 10EC (at an AI dosage of 62.5 g/ha) when applied alone gave inferior efficacy results, indicating that the combination has a better herbicidal effect.
, Claims:I/We claim:
1. A herbicidal composition comprising a) Clethodim and b) Pyrithiobac sodium and at least one agriculturally acceptable excipient.
2. The herbicidal composition as claimed in claim 1, wherein said herbicidal composition comprises a) Clethodim in an amount ranging from 5-25% w/w b) Pyrithiobac sodium in an amount ranging from 1-12% w/w and at least one agriculturally acceptable excipient.
3. The herbicidal composition as claimed in claim 2, wherein said herbicidal composition additionally comprises vegetable oil.
4. The herbicidal composition as claimed in claim 3, wherein said vegetable oil is present in an amount ranging from 0.05-10%w/w.
5. The herbicidal composition as claimed in claim 3, wherein said vegetable oil is selected from the group comprising castor oil, mustard oil, cotton seed oil, soya bean oil, ground nut oil, sunflower oil and neem seed oil.
6. The herbicidal composition as claimed in claim 2, wherein said at least one agriculturally acceptable excipient is selected from the group comprising solvent, emulsifier, spreader, and demineralised water.
7. The herbicidal composition as claimed in claim 2, wherein said solvent is present in an amount ranging from 10-30% w/w, said emulsifier is present in an amount ranging from 15-52% w/w, said spreader is present in an amount ranging from 0.2-5%w/w and demineralised water is present in an amount ranging from 20-40%w/w.
8. The herbicidal composition as claimed in claim 2, wherein said solvent is selected from the group comprising xylene, mixture of aromatic hydrocarbon solvents, cyclohexanone, N- Methyl Pyrrolidone, Dimethyl Sulfoxide, Dimethyl Formamide, N- Butyl Alcohol.
9. The herbicidal composition as claimed in claim 2, wherein said emulsifier is selected from the group comprising is selected from the group comprising Calcium benzene dodecyl benzene, Linear alkyl benzene sulphonate, Tristyrylphenol ethylene oxide derivative.
10. The herbicidal composition as claimed in claim 2, wherein said spreader is selected from the group comprising is selected from the group comprising Dioctyl sulphosuccinate and Polydimethyl siloxane.
11. The herbicidal composition as claimed in claim 2, wherein said composition is formulated in a form selected from oil dispersion (OD), suspo-emulsion (SE), suspension concentrate (SC) and microemulsion (ME).
12. The herbicidal composition as claimed in claim 2, wherein said composition is formulated as a microemulsion.
13. A process for preparing a micro emulsion concentrate comprising the following steps:
i. Solvent was taken in the required amount.
ii. Pyrithiobac sodium technical and Clethodim technical were added and dissolved properly.
iii. Emulsifier and spreader were added and mixed properly. This was followed by addition of vegetable oil.
iv. Water was added, and the mixture was stirred until it converted into a clear homogenous liquid.
14. The process as claimed in claim 13, wherein,
1. Clethodim was added an amount ranging from 5-25% w/w
2. Pyrithiobac sodium was added in an amount ranging from 1-12% w/w
3. Solvent was added in an amount ranging from 10-30% w/w
4. Vegetable oil was added in an amount ranging from 0.05-10% w/w
5. Emulsifier was added in an amount ranging from 15-52% w/w
6. Spreader was added in an amount ranging from 0.2-5% w/w.
15. A method of controlling undesired vegetation in cotton crop, said method comprising applying at the locus of the undesired vegetation, a herbicidally effective amount of the herbicidal composition as claimed in any of the preceding claims.
16. The method of controlling undesired vegetation in cotton crop as claimed in claim 15, wherein said herbicidal composition comprises a) Clethodim in an amount ranging from 5-25% w/w b) Pyrithiobac sodium in an amount ranging from 1-12% w/w and at least one agriculturally acceptable excipient.
17. The method of controlling undesired vegetation in cotton crop as claimed in claim 15, wherein said herbicidal composition comprises a) Clethodim in an amount ranging from 5-25% w/w b) Pyrithiobac sodium in an amount ranging from 1-12% w/w c) Vegetable oil in an amount ranging from in an amount ranging from 0.05-10% w/w and at least one agriculturally acceptable excipient.

Dated This 5th Day of March, 2024
Ruchi Bhatnagar
IN/PA-3497 Agent for the applicant