DESC:FIELD OF THE INVENTION
The present invention relates to a herbicidal composition. More particularly, the present invention relates to a synergistic herbicidal composition, comprising a fenoxaprop ester, acetolactate synthase (ALS) inhibitor and Pretilachlor.
BACKGROUND OF THE INVENTION
Chemical herbicides of many types have been disclosed in the literature and a large number are in commercial use. These known herbicides can be effective against different types of undesirable vegetation and can act in different ways. For example, some herbicides are particularly useful when applied to broad leaf plants while others are more useful when applied to grassy plants.
Herbicides from the group of aryloxyphenoxypropionic esters are known from numerous documents. Thus, for example, the herbicidal action of numerous such compounds is described in U.S. Pat. Nos. 6,908,883 B2 and 6,887,827 B2. Some of the aryloxyphenoxypropionic esters mentioned therein exhibit a satisfactory herbicidal action against harmful plants occurring in different crops.
However, in practice, there are frequent disadvantages associated with use of the aryloxyphenoxypropionic esters known from these documents. The herbicidal activity is not always satisfactory or with a satisfactory herbicidal activity undesirable damage to the plants is observed.
The effectiveness of herbicides depends, inter alia, on the type of herbicide used, the application rate thereof, the composition, the harmful plants to be combated each time, the climatic and soil conditions, and the like. A further criterion is the duration of the action or the rate of degradation of the herbicide. Changes in the sensitivity of harmful plants to an active substance which may occur with relatively long use or in geographically restricted areas are also to be taken into account, if appropriate. Such changes are expressed as a more or less serious loss in activity and can only to a limited extent be compensated for by higher herbicide application rates.
Due to multitude of possible influencing factors, there is virtually no individual active substance which combines in itself the properties desired for different requirements, in particular with regard to the harmful plant species and the climatic zones. In addition, there is the constant problem of achieving the effect with an ever lower herbicide application rate. A lower application rate reduces not only the amount of an active substance required for the application but generally also reduces the amounts of formulation auxiliaries necessary. Both reduce the economic cost and improve the ecological compatibility of the herbicide treatment.
One method frequently used for improving the application profile of a herbicide consists in combining one or more other active substances which contribute to the additional properties desired. However, the combined use of several active substances not infrequently results in phenomena of physical and biological incompatibility, e.g. lack of stability of a combined formulation, decomposition of an active substance or antagonism of the active substances. On the other hand, what is desired are combinations of active substances with a favourable activity profile, high stability and the greatest possible synergistically strengthened activity which makes possible a reduction in the application rate in comparison with individual application of the active substances to be combined.
US 8673814 B2 and US 20140323299 A1 describe herbicidal mixtures of particular aryloxyphenoxypropionic esters with various herbicides. CA 2502743 A1 describes herbicidal mixtures of particular aryloxyphenoxypropionates with safeners. However, in practice, there are serious disadvantages to these mixtures. Thus, their compatibility with regard to useful plants, is not always satisfactory and their activity with regard to harmful plants is likewise not always satisfactory.
Although, Fenoxaprop ester herbicides are quite well adapted for application to cereal crops and have found widespread acceptance, it has been observed that when a Fenoxaprop ester herbicide, particularly Fenoxaprop-p-ethyl or a Fenoxaprop lower alkyl ester, is mixed with certain other herbicides, the Fenoxaprop ester herbicide can degraded more rapidly than if the Fenoxaprop herbicide were not mixed with the other herbicides. This has been particularly observed when a Fenoxaprop ester is mixed with herbicides that act as weak acids, such as pyrasulfotole and bromoxynil. This increased degradation of Fenoxaprop esters can be disadvantageous to a farmer because it can decrease the useful shelf life of a Fenoxaprop ester containing herbicidal composition.
The present invention relates generally to herbicidal compositions or formulations, and to methods of using such compositions to kill, or control the growth and proliferation of, unwanted plants. In particular, the present invention relates to herbicidal compositions, as well as their methods of use, which comprise aryloxyphenoxypropionic esters, or a herbicidal derivative thereof, acetolactate synthase (ALS) inhibitors and Pretilachlor. Such compositions cause early visual symptoms of treatment and/or enhanced effectiveness or control when applied to the foliage of plants and have a long shelf life.
SUMMARY OF THE INVENTION
In accordance with an embodiment of the invention, there is provided a synergistic herbicidal composition, comprising: (a) a aryloxyphenoxypropionic ester; (b) at least one acetolactate synthase (ALS) inhibitor; (c) Pretilachlor; and (d) additives.
In accordance with another embodiment of the invention, the aryloxyphenoxypropionic ester is Fenoxaprop ester.
In accordance with still another embodiment of the invention, the Fenoxaprop ester is Fenoxaprop-p-ethyl.
In accordance with still yet another embodiment of the invention, the ALS inhibitor is Chlorimuron ethyl.
Preferably, the synergistic herbicidal composition comprises Fenoxaprop-p-ethyl, Chlorimuron ethyl and Pretilachlor in a ratio ranging from 3.00:0.60:50 to 5.00:0.60:50. Further, Fenoxaprop-p-ethyl is present in an amount of 3 to 5%, Pretilachlor is present in an amount of 50% and Chlorimuron ethyl is present in an amount of 0.6%.
The synergistic herbicidal composition of the present invention comprises additives selected from the group consisting of solvent, emulsifier, anti-freezing agent, defoamer, thickener or viscosity modifier, and water, and the composition is in the form of an oil in water emulsion (EW).
The synergistic herbicidal composition comprises solvent in an amount in the range from 1 to 10%, preferably 5%, emulsifier in an amount in the range from 0 to 15%, preferably 12%, the anti-freezing agent in an amount in the range from 1 to 5%, preferably 3%, the defoamer in an amount in the range from 0.01 to 0.50%, preferably 0.50%, and the thickener or viscosity modifier is present in an amount in the range from 0.10 to 0.30%, preferably 0.10%.
In accordance with a further embodiment of the invention, the synergistic herbicidal composition is non-phytotoxic.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1. is a flowchart for preparing a synergistic herbicidal composition in the form of an oil in water emulsion (EW).
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a novel, stable and synergistic herbicidal combination. The novel combination of the present invention comprises combination of aryloxyphenoxypropionic ester, ALS inhibitor and Pretilachlor along with other additives.
The term "agrochemically effective amount" is that quantity of active agent, applied in any amount which will provide the required control of weeds. The particular amount is dependent upon many factors including, for example, the crop and weeds sought to be controlled and environmental conditions. The selection of the proper quantity of active agent to be applied, however, is within the expertise of one skilled in the art.
It is to be noted, as used in the specification and claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound includes a mixture of two or more compounds. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. The expression of various quantities in the terms of “% w/w” or “%” means the percentage by weight, relative to the weight of the total composition unless otherwise specified.
As used herein SL formulation, EC formulation, EW formulation, SC formulation and SG formulation are the international denominations adopted by the FAO (Food and Agriculture Organization of the United Nations) to designate soluble liquid, emulsifiable concentrate, oil in water emulsion, suspension concentrate and soluble granules, respectively.
It is an object of the present invention to provide herbicidal combinations, in particular for use in paddy, with improved properties in comparison with the state of the art.
Accordingly the inventors of the present invention, have formulated a synergistic herbicidal composition, comprising: (a) aryloxyphenoxypropionic ester; (b) at least one acetolactate synthase (ALS) inhibitor; (c) Pretilachlor; and (d) additives.
Aryloxyphenoxypropionic esters typically act as acetyl-CoA carboxylase inhibitors. Examples include Fenoxaprop esters, such as Fenoxaprop-p-ethyl, commercially available from different sources. The Fenoxaprop esters, such as Fenoxaprop-p-ethyl, are particularly useful for application to cereal crops to combat grassy weeds.
The formula for Fenoxaprop-p-ethyl is shown below.

Non-limiting examples of aryloxyphenoxypropionic esters are described, for example, in U.S. Pat. Nos. 6,908,883 B2 and 6,887,827 B2. The present invention will be described with respect to the use of a Fenoxaprop ester, such as Fenoxaprop-p-ethyl, in an herbicide composition. However, it is to be understood that the invention is not limited to use with Fenoxaprop-p-ethyl but is believed to be applicable to other aryloxyphenoxypropionic esters, e.g., Fenoxaprop esters. In one non-limiting embodiment, the Fenoxaprop ester is Fenoxaprop-p-ethyl.
Fenoxaprop-p-ethyl is the common name used for (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid; R-2-[4-(6-chlorobenzoxazol-2-yloxy)phenoxy]propionic acid and having chemical formula C18H16ClNO5 and belonging to aryloxyphenoxypropionic group of herbicides. Fenoxaprop-p-ethyl was reported by H. P. Huff et al. (Proc. Br. Crop Prot. Conf. –Weeds, 1989, 2, 717) and introduced by Hoechst AG (Now Bayer AG). Fenoxaprop-p-ethyl is commonly available in the market as Emulsifiable Concentrate (EC) formulation of different concentrations. In accordance with an aspect of the invention, Fenoxaprop-p-ethyl is present in an amount of 3 to 5%.
According to another aspect of the present invention, ALS inhibitor herbicides include sulfonylureas such as rimsulfuron (DPX 9636), metsulfuron, metsulfuron-methyl, ethametsulfuron, nicosulfuron, triasulfuron, primisulfuron, bensulfuron, Chlorimuron, chorimuron-ethyl, chlorsulfuron, sulfometuron, thifensulfuron, tribenuron, triflusulfuron, clopyrasulfuron, and pyrazasulfuron; sulfonamides such as flumetsulam (DE498); and imidazolinones such as imazaquin, imazamethabenz, imazapyr, imazmethapyr and Imazethapyr.
Chlorimuron ethyl is the common name used for ethyl 2-(4-chloro-6-methoxypyrimidin-2-ylcarbamoylsulfamoyl) benzoate and having chemical formula C15H15ClN4O6S and belonging to sulfonylurea group of herbicides. It is represented by the following structural formula.

This was first described in US 4394506 and introduced in United States in 1986 by E.I. Dupont. Chlorimuron ethyl is commonly available in the market as 25 percent wettable powder (WP) formulation. In accordance with an aspect of the invention, Chlorimuron ethyl is preferably present in an amount of 0.60% w/w.
Pretilachlor (2-chloro-2’,6’-diethyl-N-(2-propoxyethyl)acetanilide) is an herbicide of the chloroacetamide class having chemical formula C17H26ClNO2. It is usually an agro chemical liquid substance with a low melting point described in BE800471, GB1438311 and GB1438312. Pretilachlor is mainly used for control of annual grasses and sedges in transplanted and seeded rice. Pretilachlor is commonly available in the market as 50 percent emulsifiable concentrate (EC) and 37 percent oil in water emulsion (EW) formulation. In accordance with an aspect of the invention, Pretilachlor is present in an amount of 50% w/w. Pretilachlor is represented by the following structural formula.

Preferably, Fenoxaprop-p-ethyl, Chlorimuron ethyl and Pretilachlor are present in ratios ranging from 3.00:0.60:50.00 to 5.00:0.60:50.00.
The following are possible, for example, as general formulation possibilities: emulisifiable concentrates (EC), aqueous solutions (SL), emulsions (EW), such as oil-in-water and water-in-oil emulsions, sprayable solutions or emulsions, oil- or water-based dispersions, suspoemulsions, Ultra Low Volume (ULV) formulations or microcapsules.
Preferably, the synergistic herbicidal composition, further comprises additives selected from the group consisting of solvent, emulsifier, anti-freezing agent, defoamer, viscosity modifier or thickener, and water and the composition is in the form of an oil in water emulsion (EW). It is stable emulsion of active ingredient(s) in an aqueous phase, intended for dilution with water before use. The active ingredient is normally a liquid and forms the dispersed oil phase, but it is also possible to emulsify a solid or liquid active ingredient dissolved in a water immiscible solvent. Emulsions, like suspension concentrates, are metastable systems. Therefore, after transportation and storage it may be necessary to re-homogenize the formulation, either by shaking small containers or by stirring the contents of large containers.
Suitable solvents useful in accordance with the invention are C IX, cyclohexanone, N-methyl pyrollidone (NMP), butanol and combinations thereof, and present in an amount in the range from 1 to 10%, preferably 5%. The term “C IX” refers to a solvent which mainly comprises of hydrocarbons with nine carbon atoms.
It is desirable to have an emulsifier in the synergistic herbicidal composition. An emulsifier is a substance that stabilizes an emulsion by increasing its kinetic stability. One class of emulsifiers are known as "surface active agents", or surfactants. Non-limiting examples of emulsifiers that can be used in the present invention include nonionic and anionic surfactants. Each of these surfactants can be used either individually or in combination in an amount in the range from 0 to 15%, preferably 12%.
An anti-freezing agent is generally added to herbicidal compositions, to prevent the aqueous compositions from freezing. Suitable anti-freezing agents useful herein, but not limited to, include propylene glycol, di-ethylene glycol and mono-ethylene glycol, and combinations thereof. Preferably, the anti-freezing agent is present in an amount in the range from 1 to 5%, and preferably 3%.
A defoamer, also called as anti-foam, is generally added to an herbicidal composition as foam formation prevents the efficient filling of a container. Preferably, the defoamer is dimethyl polysiloxane emulsion and present in an amount in the range from 0.01 to 0.50%, preferably 0.50%.
It is necessary to add a thickener or a viscosity modifier to an herbicidal composition to reduce the tendency of the herbicide composition to disperse when sprayed, and decrease the likelihood of it being rinsed off of the crops. Preferably, the synergistic herbicidal composition comprises Xanthan gum as thickener or viscosity modifier in an amount in the range from 0.10-0.30%, preferably 0.10%.
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 skilled in the art. The following examples illustrate the basic methodology and versatility of the present invention.

EXAMPLES
Examples 1 and 2
The unit of each value below is “% w/w” i. e. the percentage by weight, relative to the weight of the total solution or composition unless otherwise specified. The compositions illustrated in Table 1 are formulated as an oil in water emulsion (EW).
Table 1: Synergistic herbicidal compositions
No.
Component Function Example (%)
1 2
1 Fenoxaprop-p-ethyl
A.I. 3.00 5.00
2 Chlorimuron ethyl
A.I. 0.60 0.60
3 Pretilachlor A.I. 50.00 50.00
4 Cyclohexanone/Butanol/C-IX/N-methyl pyrollidone Solvent 5.00 5.00
5 Blend of Anionic & Nonionic surfactants Emulsifier 12.00 12.00
6 Propylene glycol/ Di-ethylene glycol/ Mono-ethylene glycol Anti-freezeing agent
3.00 3.00
7 Dimethyl polysiloxane Defoamer
0.50 0.50
8 Xanthan gum Viscosity Modifier or thickener 0.10 0.10
9 D.M. Water Solvent Q.S. Q.S.
A.I.= Active Ingredient
Q.S.= quantity sufficient
D.M. = de-mineralized water
The aforementioned herbicidal composition can be formulated as an oil in water emulsion (EW) by the process described below.
Process for preparing synergistic herbicidal composition in the form of oil in water emulsion (EW):
The synergistic herbicidal compositions of Examples 1 and 2 are prepared by a process depicted in figure 1. The raw materials required for preparing compositions of examples 1 and 2 are illustrated in table 2 under the column headings 1 and 2 respectively. The process for manufacturing 100 kg batch size of synergistic herbicidal composition is provided. All the raw materials are verified for conformance to the laid down individual specifications.
Entries for Fenoxaprop-p-ethyl, Chlorimuron ethyl and Pretilachlor in table 2 differ from those in table 1 as entries in table 1 are for 100% pure compounds, whereas those in table 2 are for technical ones, i.e. those containing a certain percentage of impurities.
The amounts of active ingredients presented in table 2 may be greater than the values calculated taking into account the percentage purity of the active ingredients, to compensate for losses of said ingredients during the manufacturing process. It was observed that following said procedure on industrial scale the final yield of A.I. will be similar or same as to standardized values.
The required quantities of raw materials as illustrated in Table 2 below are weighed and transferred through the auto-batching system.
Preparation of organic phase: Dissolve required quantities of Fenoxaprop-p-ethyl technical, Chlorimuron ethyl technical, Pretilachlor technical in solvent with constant stirring and then add emulsifier.
Preparation of aqueous phase: Take water in homogenizer, add anti-freezing agent and mix well to get a homogenous mixture. To this homogenized mixture add anti-foaming agent or defoamer.
Add organic phase to aqueous phase slowly under vigorous stirring and mix well for an hour. After that, add viscosity modifier or thickener under gentle stirring.
After homogeneous mixing for an hour, the mixture is transferred to an agitating vessel and agitated for 2 hours. The quality of in-process sample is checked for conformance to the specifications. The quality approved in-process sample is transferred to the holding tank after passing through sparkler filter pump for packing as per the requirements.
Table 2: Quantities of the *TGAI and raw materials charged
Component Function Quantities of materials charged (kg)
1 2
Fenoxaprop-p-Ethyl (based on 95% w/w minimum purity) *TGAI
3.16 5.27
Chlorimuron Ethyl (based on 95% w/w minimum purity) *TGAI
0.64 0.64
Pretilachlor (based on 95% w/w minimum purity) *TGAI
52.65 52.65
Cyclohexanone/Butanol/C-IX/N-methyl pyrollidone Solvent 5.00 5.00
Blend of Anionic & Nonionic
Surfactant Emulsifier 12.00 12.00
Propylene glycol/ Di-ethylene glycol/ Mono-ethylene glycol Anti-freezing Agent
3.00 3.00
Dimethyl polysiloxane Defoamer
0.50 0.50
Xanthan gum Viscosity Modifier 0.10 0.10
D.M. Water Solvent 22.95 20.84
*Technical grade active ingredient

Evaluation of bio-efficacy of synergistic herbicidal composition against weed spectrum in paddy crop
Field trials were performed to evaluate the biological efficacy of the novel herbicidal composition of present invention against the commonly occurring weed spectrum in paddy crop. This evaluation was performed by comparing the claimed novel herbicidal composition in the present specification against the marketed reference products, i.e., Fenoxaprop-p-Ethyl 9.3% EC; Chlorimuron Ethyl 25% WP, Pretilachlor 50% EC and Bispyribac Sodium 10% SC.
Observation on weed population, dry weight and weed control efficiency (WCE %) was calculated by throwing square quadrant randomly in the trial plots and calculating the number of weeds based on type of weeds before the spray and 15 DAA, 30 DAA and 45 DAA of the spray. Area for experiment was marked for different plot sizes and application was made using high volume knapsack sprayer at 15 days after sowing (DAS). Based on various doses, weighed quantity of test products were dissolved in 5 liter of water/treatment and sprayed uniformly. All the recommended agronomic practices are followed as per good agriculture practices (GAP) including the use of recommended insecticides and fungicides for control of insect pest and diseases. Experimental design was in randomized blocks with seven replication and each plot measured an area of 100 sq. m (10 m x 10 m).
Details of Experiment
Target weeds: Annual and perennial grasses, sedges and broad leaved weeds
Crop: Transplanted Paddy
Application Method: high volume knapsack sprayer fitted with flat fan nozzle
The treatment details are tabulated in Table 3 below.
Table 3: Treatment details for evaluation of bio-efficacy of herbicidal compositions against weed spectrum in transplanted Paddy
Particulars Treatment Dose /Ha Dose a.i./ha (g)
Time of Application
T1 Fenoxaprop-p-Ethyl 3% + Chlorimuron Ethyl 0.6% + Pretilachlor 50% EW 1000 mL
30 + 6 + 500 15 DAS
T2 1200 mL
36 + 7.2 + 600
T3 Fenoxaprop-p-Ethyl 5% + Chlorimuron Ethyl 0.6% + Pretialchlor 50% EW 1000 mL
50 + 6 + 500
T4 1200 mL
60 + 7.2 + 600
T5 Fenoxaprop-p-Ethyl 9.3% EC 625 mL
56.25
T6 Chlorimuron Ethyl 25% WP 24 gm 6
T7 Pretilachlor 50% EC 1500 mL
750
T8 Bispyribac Sodium 10% SC 200 mL
20
T9 Control (Water Spray) -- --
The bio-efficacy of different treatment schedules on paddy crop and the treatment wise yield data of paddy crop is summarized in Tables 4-7 below.

Table 4: Effect of herbicidal compositions on total weed count (no./m2) in transplanted paddy
No.
Treatments Dose per acre Weed Population (no./m2)
Narrow leaved weeds Sedges Broad leaved weeds
15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA*
1 T1 1000 mL
2.55
(6.02) 2.37
(5.12) 2.57
(6.12) 2.23
(4.49) 2.12
(4.01) 2.35
(5.00) 1.87
(3.01) 1.62
(2.12) 1.83
(2.85)
2 T2 1200 mL
2.49
(5.71) 2.32
(4.89) 2.41
(5.30) 2.23
(4.49) 2.10
(3.91) 2.12
(4.01) 1.83
(2.85) 1.55
(1.89) 1.90
(3.10)
3 T3 1000 mL
1.93
(3.23) 2.12
(3.98) 2.13
(4.02) 2.01
(3.56) 1.58
(2.01) 1.23
(1.02) 1.58
(2.01) 1.47
(1.71) 1.58
(2.01)
4 T4 1200 mL
1.23
(1.02) 1.72
(2.45) 1.99
(3.45) 1.32
(1.23) 1.26
(1.08) 1.18
(0.89) 0.99
(0.49) 1.23
(1.01) 1.51
(1.79)
5 T5 625 mL
4.21
(17.23) 3.68
(13.02) 4.18
(16.96) 4.94
(23.89) 4.53
(20.01) 4.66
(21.23) 3.57
(12.23) 3.26
(10.12) 3.39
(11.01)
6 T6 24 gm 4.06
(16.02) 3.79
(13.85) 4.04
(15.85) 3.27
(10.20) 3.15
(9.45) 3.24
(10.02) 2.76
(7.10) 2.55
(6.01) 2.71
(6.85)
7 T7 1500 mL
3.39
(11.02) 2.89
(7.85) 4.74
(21.96) 2.84
(7.56) 2.74
(7.01) 4.58
(20.45) 2.36
(5.09) 2.23
(4.49) 3.27
(10.21)
8 T8 200 mL
2.88
(7.82) 2.48
(5.66) 3.22
(9.85) 2.49
(5.70) 2.34
(4.96) 2.77
(7.19) 2.13
(4.02) 2.15
(4.12) 2.37
(5.10)
9 T9 -- 6.59
(42.99) 7.24
(51.96) 7.79
(60.19) 6.29
(39.02) 6.83
(46.10) 7.34
(53.42) 4.84
(22.89) 5.29
(27.52) 5.66
(31.56)
SEm+ 0.04 0.03 0.04 0.04 0.03 0.03 0.02 0.02 0.03
CD 5% - 0.11 0.09 0.11 0.13 0.08 0.08 0.06 0.06 0.10
* DAA: Days after application; CD 5%: Critical Difference; g = Gram; m2 = Square meter; mL = Millilitre, g = Gram; Values in brackets are original values
Table 5: Effect of herbicidal compositions on total weed dry weight (g/m2) in transplanted paddy
No.
Treatments Dose per acre Weed Dry Weight (g/m2)

Narrow leaved weeds Sedges Broad leaved weeds
15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA*
1 T1 1000 mL
1.87
(3.01) 1.79
(2.71) 1.90
(3.10) 2.10
(3.89) 1.87
(3.01) 2.10
(3.89) 1.87
(3.00) 1.80
(2.75) 2.01
(3.56)
2 T2 1200 mL
1.83
(2.85) 1.55
(1.89) 1.58
(2.01) 1.94
(3.25) 1.80
(2.75) 1.96
(3.35) 1.80
(2.75) 1.71
(2.41) 1.87
(3.00)
3 T3 1000 mL
1.58
(2.01) 1.62
(2.12) 1.83
(2.85) 1.27
(1.12) 1.72
(2.45) 1.86
(2.96) 1.55
(1.89) 1.88
(3.02) 1.80
(2.75)
4 T4 1200 mL
0.99
(0.49) 1.23
(1.01) 1.51
(1.79) 0.96
(0.42) 1.05
(0.61) 1.16
(0.85) 1.06
(0.63) 1.14
(0.81) 1.23
(1.02)
5 T5 625 mL
2.36
(5.09) 3.27
(10.21) 3.79
(13.85) 2.57
(6.13) 3.26
(10.12) 4.09
(16.20) 3.47
(11.56) 3.67
(12.96) 4.32
(18.20)
6 T6 24 gm 2.76
(7.10) 2.55
(6.01) 3.22
(9.85) 2.82
(7.45) 2.91
(7.96) 3.26
(10.12) 2.58
(6.15) 2.72
(6.91) 2.91
(7.96)
7 T7 1500 mL
3.26
(10.12) 3.39
(11.01) 3.57
(12.23) 3.89
(14.63) 3.96
(15.20) 4.06
(16.02) 2.46
(5.55) 2.53
(5.90) 2.72
(6.91)
8 T8 200 mL
1.98
(3.41) 2.23
(4.49) 2.39
(5.23) 1.99
(3.45) 2.12
(4.01) 2.15
(4.12) 1.87
(3.01) 1.98
(3.42) 2.82
(7.45)
9 T9 -- 4.84
(22.89) 5.29
(27.52) 5.66
(31.56) 5.18
(26.32) 5.84
(33.56) 6.25
(38.56) 4.62
(20.89) 6.06
(36.23) 6.33
(39.61)
SEm+ 0.02 0.02 0.03 0.01 0.02 0.02 0.04 0.03 0.02
CD 5% - 0.06 0.06 0.10 0.04 0.07 0.06 0.11 0.08 0.05
* DAA: Days after application; CD 5%: Critical Difference; g = Gram; m2 = Square meter; mL = Millilitre
Values in brackets are original values

Table 6: Weed Control Efficacy (WCE) (%) in transplanted paddy, of different herbicidal compositions
No.
Treatments Dose per acre Weed Control Efficacy (%)
Narrow leaved weeds Sedges Broad leaved weeds
15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA*
1 T1 1000 mL
86.85 90.15 90.17 85.22 91.03 89.91 85.63 92.40 91.01
2 T2 1200 mL
87.54 93.13 93.63 87.65 91.80 91.31 86.83 93.34 92.42
3 T3 1000 mL
91.21 92.29 90.96 95.74 92.69 92.32 90.95 91.66 93.05
4 T4 1200 mL
97.85 96.32 94.32 98.40 98.18 97.79 96.98 97.76 97.42
5 T5 625 mL
77.76 62.89 56.11 76.70 69.84 57.98 44.66 64.22 54.05
6 T6 24 gm 68.98 78.16 68.78 71.69 76.28 73.75 70.56 80.92 79.90
7 T7 1500 mL
55.78 59.99 61.24 44.41 54.70 58.45 73.43 83.71 82.55
8 T8 200 mL
85.10 83.68 83.42 86.89 88.05 89.31 85.59 90.56 81.19
9 T9 -- -- -- -- -- -- -- -- -- --
*DAA: Days after application; g = Gram; mL = Millilitre
Table 7: Treatment wise yield of transplanted paddy
Treatment Grain yield
(kg ha-1) % increase in grain yield over control Straw yield
(kg ha-1) % increase in straw yield over control
T1 4308.0 36.50 4712.0 32.25
T2 4353.0 37.92 4796.0 34.61
T3 4392.0 39.16 4801.0 34.75
T4 4398.0 39.35 4820.0 35.28
T5 3945.0 25.00 4411.0 23.80
T6 4012.0 27.12 4452.0 24.95
T7 4068.0 28.89 4523.0 26.94
T8 4198.0 33.01 4769.0 33.85
T9 3156.0 - 3563.0 -
SEm+ 35.56 - 33.33 -
CD 5% 106.62 - 99.92 -
CD 5%: Critical Difference
Data presented in table 4 shows that weed population was significantly affected by all the treatments compared to control when observed at 15, 30 and 45 days after application (DAA). At 45 DAA the synergistic herbicide composition of the present invention, @ all the doses, recorded lowest weed population closely followed by T8 i.e. bispyribac sodium 10% SC @ recommended dose. Similar results were observed in case of Weed dry weight and WCE. Also, highest grain and straw yield were recorded on treatment with Fenoxaprop-p-ethyl 5%, Chlorimuron ethyl 0.6% and Pretilachlor 50% EW @ dose of 1200 mL/ha.
Phytotoxic effect of herbicidal compositions on transplanted paddy
Visual observation on phytotoxicity were recorded for leaf injury on tip/surface, Epinasty/Hyponasty, and wilting, etc. on 0-10 scale (Table 8) at 1, 3, 7, 14 and 21 days after application (DAA) and the average values are presented in table 9.
Table 8. Phytotoxicity visual scoring 0-10
Score Phytotoxicity (Percent)
0 No phytotoxicity
1 1 – 10
2 11 – 20
3 21 – 30
4 31 – 40
5 41 – 50
6 51 – 60
7 61 – 70
8 71 – 80
9 & 10 Complete destruction

Table 9: Phytotoxicity of herbicidal compositions on transplanted paddy
No.
Treatments Dose (mL/ha)
Phytotoxicity (Days after Application)
1
3
7
14
21

1 Fenoxaprop-p-Ethyl 3% + Chlorimuron Ethyl 0.6% + Pretialchlor 50% EW 1000 0 0 0 0 0
2 2000 0 0 0 0 0
3 3000 0 0 0 0 0
4 4000 0 0 0 0 0
5 Fenoxaprop-p-Ethyl 5% + Chlorimuron Ethyl 0.6% + Pretialchlor 50% EW 1000 0 0 0 0 0
6 2000 0 0 0 0 0
7 3000 0 0 0 0 0
8 4000 0 0 0 0 0
9 Control - 0 0 0 0 0
0= No Phytoxicity
The data presented in Table 9 above shows that no phytotoxicity was observed in case of compositions comprising Fenoxaprop-p-Ethyl, Chlorimuron Ethyl, and Pretialchlor EW at 1000 mL/ha, 2000 mL/ha, 3000 mL/ha as well as 4000 mL/ha.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present investigation. It is to be understood that no limitations with respect to the specific aspect illustrated is intended or should be inferred. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.

CLAIMS:
We claim:
1. A synergistic herbicidal composition, comprising: a aryloxyphenoxypropionic ester; at least one acetolactate synthase (ALS) inhibitor; Pretilachlor; and additives.
2. The synergistic herbicidal composition, as claimed in claim 1, wherein the aryloxyphenoxypropionic ester is Fenoxaprop ester.
3. The synergistic herbicidal composition, as claimed in claim 2, wherein the Fenoxaprop ester is Fenoxaprop-p-ethyl.
4. The synergistic herbicidal composition, as claimed in claims 1 to 3, wherein the ALS inhibitor is selected from the group consisting of: (a) sulfonylureas such as rimsulfuron (DPX 9636), metsulfuron, metsulfuron-methyl, ethametsulfuron, nicosulfuron, triasulfuron, primisulfuron, bensulfuron, Chlorimuron, chorimuron-ethyl, chlorsulfuron, sulfometuron, thifensulfuron, tribenuron, triflusulfuron, clopyrasulfuron, and pyrazasulfuron; b) sulfonamides such as flumetsulam (DE498); and c) imidazolinones such as imazaquin, imazamethabenz, imazapyr, imazmethapyr and Imazethapyr.
5. The synergistic herbicidal composition, as claimed in claims 1 to 4, wherein the ALS inhibitor is Chlorimuron ethyl.
6. The synergistic herbicidal composition as claimed in claims 4 and 5, wherein Fenoxaprop-p-ethyl, Chlorimuron ethyl and Pretilachlor are present in a ratio ranging from 3.00:0.60:50 to 5.00:0.60:50.
7. The synergistic herbicidal composition, as claimed in claims 4, 5 and 6, wherein Fenoxaprop-p-ethyl is present in an amount of 3 to 5%, Pretilachlor is present in an amount of 50% and Chlorimuron ethyl is present in an amount of 0.6%.
8. The synergistic herbicidal composition, as claimed in claims 1 to 7, wherein the composition may be formulated as an emulsifiable concentrate (EC), aqueous solutions (SL), emulsions (EW) such as oil-in-water and water-in-oil emulsions, sprayable solutions or emulsions, oil- or water-based dispersions, suspo-emulsions (SE), Ultra Low Volume (ULV) formulations or microcapsules.
9. The synergistic herbicidal composition, as claimed in claims 1 to 8, wherein the additives are selected from the group consisting of solvent, emulsifier, anti-freezing agent, defoamer, thickener or viscosity modifier, and water, and the composition is in the form of an oil in water emulsion (EW).
10. The synergistic herbicidal composition, as claimed in claim 9, wherein the solvent is selected from the group consisting of C IX, cyclohexanone, N-methyl pyrollidone, butanol and combinations thereof, and present in an amount in the range from 1 to 10%, preferably 5%.
11. The synergistic herbicidal composition, as claimed in claim 9, wherein the emulsifier is selected from the group consisting of a nonionic surfactant, anionic surfactant and combinations thereof, and present in an amount in the range from 0 to 15%, preferably 12%.
12. The synergistic herbicidal composition as claimed in claim 9, wherein the anti-freezing agent is selected from the group consisting of propylene glycol, di-ethylene glycol, mono-ethylene glycol and combinations thereof, and present in an amount in the range from 1 to 5%, preferably 3%.
13. The synergistic herbicidal composition as claimed in claim 9, wherein the defoamer is dimethyl polysiloxane emulsion and present in an amount in the range from 0.01 to 0.50%, and preferably 0.50%.
14. The synergistic herbicidal composition as claimed in claim 9, wherein the thickener or viscosity modifier is Xanthan gum and present in an amount in the range from 0.10 to 0.30%, preferably 0.10%.

15. The synergistic herbicidal composition as claimed in any of the claims 1 to 14, wherein the composition is non-phytotoxic.