DESC:FIELD OF THE INVENTION
The present invention relates to a herbicidal composition. More particularly, the present invention relates to a synergistic herbicide composition, comprising Aryloxyphenoxypropionic ester and acetolactate synthase (ALS) inhibitors.
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 including soybean.
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, in particular soybean, 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, and acetolactate synthase (ALS) inhibitors. 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 two acetolactate synthase (ALS) inhibitors; and (c) 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 inhibitors are Chlorimuron ethyl and Imazethapyr.
Preferably, Fenoxaprop-p-ethyl, Chlorimuron ethyl and Imazethapyr are present in ratios ranging from 1.00:0.10:1.67 to 1.00:0.15:1.67. Further, Fenoxaprop-p-ethyl is present in an amount of 6%, Imazethapyr is present in an amount of 10% and Chlorimuron ethyl is present in an amount in the range from 0.60 to 0.90%.
The synergistic herbicidal composition of the present invention comprises additives selected from the group consisting of anti-freezing agent, dispersing cum wetting agent, defoamer, biocide, thickener, water and combinations thereof, and the composition is in the form of a suspension concentrate (SC).
The synergistic herbicidal composition comprises the anti-freezing agent in an amount of 1.00-8.00%, the dispersing cum wetting agent in an amount of 2.00-10.00%, the defoamer in an amount of 0.01-0.50%, and preferably 0.20%, the biocide in an amount of 0.01-0.50%, and preferably 0.20%, and the thickener is present in an amount of 0.10-0.50%, and preferably 0.20%.
In accordance with a further embodiment of the invention, the synergistic herbicidal composition of the present invention is non-phytotoxic.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1. is a flowchart for preparing a synergistic herbicidal composition in the form of a suspension concentrate (SC).
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 and ALS inhibitors 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, 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, suspension concentrate and soluble granules, respectively.
It is an object of the present invention to provide herbicidal combinations, in particular for use in soybean crop, 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 two acetolactate synthase (ALS) inhibitors; and (c) 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 6% w/w.
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 present in an amount of 0.6-0.9% w/w. In a preferred aspect, the Chlorimuron ethyl is present in an amount of 0.6% w/w.
Imazethapyr is the common name used for 5-ethyl-2-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]nicotinic acid and having chemical formula C15H19N3O3 and belonging to a relatively new substance class of herbicides imidazolinones. This was described in US 4798619 and reported by T. Malefyt et al. (Abstr. 1984 Weed Science Society Mtg., Miami, p. 18, Abstract 49) 1984. It is represented by the following structural formula.

Imazethapyr is commonly available in the market as 10 percent soluble liquid and 70 percent water dispersible granules (WG) formulation. In accordance with an aspect of the invention, Imazethapyr is present in an amount of 10% w/w.
Preferably, Fenoxaprop-p-ethyl, Chlorimuron ethyl and Imazethapyr are present in ratios ranging from 1.00:0.10:1.67 to 1.00:0.15:1.67.
The synergistic herbicidal composition, further comprises additives selected from the group consisting of anti-freezing agent, dispersing cum wetting agent, defoamer, biocide, thickener, water and combinations thereof, and the composition is in the form of a suspension concentrate (SC). The term “suspension concentrate” used herein refers to a suspension of the active herbicide and additives in a small quantity of liquid, usually water. A composition in the form of a suspension concentrate is user friendly and affords a reduced risk of occupational exposure.
An anti-freezing agent is generally added to herbicidal compositions, to prevent the aqueous compositions from freezing. Suitable anti-freezing agents useful herein include, but not limited to, propylene glycol, Diethylene glycol (DEG), Mono ethylene glycol (MEG) and combinations thereof. Preferably, the anti-freezing agent is present in an amount in the range from 1.00-8.00%, and more preferably 5.00%.
A dispersing cum wetting agent is another important component of a suspension concentrate as it facilitates the formation of a suspension of a water insoluble substrate in water. Non-limiting examples of dispersing cum wetting agents that can be used in the present invention include non-ionic surfactants and amine salt of phosphate tristyryl phenol ethylated, acrylic copolymer, ethoxylated polyarylphenol phosphate ester, each of which can be used individually or in combination, in an amount in the range from 2.00-10.00%, preferably 5%.
A defoamer, also called as anti-foam, is generally added to a 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 0.01-0.50%, and more preferably 0.2%.
The synergistic herbicidal composition may contain a biocide selected from the group consisting of Proxel GXL, formaldehyde and combinations thereof, and present in an amount in the range from 0.01-0.50%. Proxel GXL is a broad spectrum biocide for the preservation of industrial water-based products, such as the composition of the present invention, against spoilage from bacteria, yeasts and fungi.
It is necessary to add a thickener to a 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 in an amount in the range from 0.10-0.50%.
It has been surprisingly found that the synergistic herbicidal composition of present invention provides a wide spectrum control of weeds, delaying the emergence of the resistant strains of weeds, and achieving effective and economical control of undesired weeds.
The embodiments of the present invention are more particularly described in the following examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to those of skill in the art. Unless otherwise noted, all parts, percentages and ratios reported in the following examples are on a weight basis and all reagents used in the examples were obtained or are available from the chemical suppliers.
EXAMPLES
Examples 1 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 a suspension concentrate (SC) formulation.
Table 1: Synergistic herbicidal composition
No. Component Function Example (%)
1 2
1 Fenoxaprop-p-Ethyl A.I. 6.00 6.00
2 Chlorimuron Ethyl A.I. 0.60 0.90
3 Imazethapyr A.I. 10.00 10.00
4 Propylene glycol Anti-freeze Agent 5.00 5.00
5 Amine salt of phosphate tristyryl phenol ethylated Dispersing cum Wetting Agent 5.00 5.00
6 Dimethyl Polysiloxane emulsion Defoamer 0.20 0.20
7 Proxel GXL Biocide 0.20 0.20
8 Xanthan Gum Thickener 0.20 0.20
9 D.M. Water Solvent Q.S. Q.S.
A.I.= Active Ingredient
Q.S.= Quantity Sufficient
D.M. = De-mineralized
The aforementioned synergistic herbicidal compositions can be formulated as Suspension concentrate (SC) by the process described below.
Process for preparing synergistic herbicidal composition in the form of Suspension Concentrate (SC):
The synergistic herbicidal compositions of Examples 1 and 2 are prepared by the process depicted in Figure 1. All the raw materials were verified for conformance to the laid down individual specifications. 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. Entries for Fenoxaprop-p-ethyl, Chlorimuron ethyl and Imazethapyr 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, were weighed, and transferred through the auto-batching system. The dispersing cum wetting agent is first diluted in demineralized (D.M.) water and solubilized by high shear mixing, and then added along with required quantities of anti-freezing agent, Fenoxaprop ethyl technical, Chlorimuron ethyl technical, defoamer and Imazethapyr technical, into a premixing vessel, to make a homogeneous mass. Thereafter, the homogenous mass was ground to a mean particle size of 3-5 microns in a bead mil and mixed with 2% aqueous solution of xanthan gum under low stirring. Further, the quality of in-process sample was checked for conformance to the laid out specifications. Finally, the quality approved in-process sample was 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 6.32 6.32
Chlorimuron Ethyl (based on 95% w/w minimum purity) *TGAI 0.64 0.95
Imazethapyr (based on 90% w/w minimum purity) *TGAI 11.12 11.12
Propylene glycol Anti-freeze Agent 5.00 5.00
Amine salt of phosphate tristyryl phenol ethylated Dispersing cum Wetting Agent 5.00 5.00
Dimethyl Polysiloxane emulsion Defoamer 0.20 0.20
Proxel GXL Biocide 0.20 0.20
Xanthan Gum Thickener 0.20 0.20
D.M. Water Solvent 71.32 71.01
*Technical Grade Active Ingredient
Evaluation of stability of synergistic herbicidal composition comprising Fenoxaprop Ethyl, Chlorimuron ethyl and Imazethapyr.
For evaluation of stability, samples of synergistic herbicidal composition (both the compositions (Example 1 and Example 2) were evaluated and the average values are depicted in table 3) were stored at -10 0C; 54 0C and room temperature for eight weeks. At the end of the storage period, the samples were used to prepare 5% (w/v) solution (5 mL in 100 mL tap water) in 250 mL beaker with the help of mechanical stirrer at 3-4 rounds per second. The solution so obtained was passed through 45 µm mesh sieve. At the end of experiment negligible particle was detected on 45 µm mesh sieve for all the three samples. Table 3 below summarizes the effect of different temperatures on storage stability of the synergistic herbicidal composition after a storage period of eight weeks.
Table 3: Evaluation of stability of synergistic herbicidal composition comprising Fenoxaprop Ethyl, Chlorimuron Ethyl and Imazethapyr.
No. Storage condition Characteristic Requirement Result
Initial Final
1 Eight Weeks @
-10 0C Wet Sieve Test (45 µm mesh); % by mass Min. 98% 99.81% 99.37%
2 Eight Weeks @
54 0C 99.22%
3 Eight Weeks @ room temperature 99.59%
Appearance of the product was also found unchanged i.e. the white viscous liquid remained unchanged after a storage period of eight weeks in all the three storage conditions. Results presented in table 3, show that the synergistic herbicidal composition comprising Fenoxaprop ethyl, Chlorimuron ethyl and Imazethapyr has improved storage stability.

Evaluation of bio-efficacy of synergistic herbicidal composition against weed spectrum in soybean crop
Field tests of the compositions according to the present invention were conducted at various trial sites. The performance of the synergistic herbicidal composition according to the present invention was compared against the known compositions of Fenoxaprop-p-Ethyl 9.3% EC; Chlorimuron Ethyl 25% WP; Imazethapyr 70% WG and Imazethapyr 10 % SL which were evaluated against weed spectrum in soybean crop and also the vigor/yield of the crop was tested.
Area for experiment was marked for different plot sizes and application was made using high volume knapsack sprayer at 25 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 x 10 m). Observation on weed population, dry weight and weed control efficiency (WCE %) was assessed at 15, 30 and 45 days after application.
Weed Control Efficiency or Efficacy (%) = [(Weed Dry Weight in Control Plot – Weed Dry Weight in Treated Plot)/ Weed Dry Weight in Control Plot] x 100
Details of Experiment
Target weeds: Annual and perennial narrow leaved weeds and broad leaved weeds
Crop: Soybean
Application Method: high volume knapsack sprayer fitted with flat fan nozzle
The treatment details are tabulated in Table 4 below.

Table 4: Treatment details for evaluation of bio-efficacy of herbicidal compositions against weed spectrum in Soybean.
Particulars Treatment Dose /Ha Dose a.i./ha (gm) Time of Application
T1 Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.6% and Imazethapyr 10% SC 800 mL 48 + 4.8 + 80 25 DAS
T2 1000 mL 60 + 6 + 100
T3 1200 mL 72 + 7.2 + 120
T4 Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.9% and Imazethapyr 10% SC 800 mL 48 + 7.2 + 80
T5 1000 mL 60 + 9 + 100
T6 1200 mL 72 + 10.8 + 120
T7 Fenoxaprop-p-Ethyl 9.3% EC 1111 mL 100
T8 Chlorimuron Ethyl 25% WP 36 gm 9
T9 Imazethapyr 70% WDG 100 gm 70
T10 Imazethapyr 10 % SL 1000 mL 100
T11 Control (Water Spray) -- --
The bio-efficacy of different treatment schedules on Soybean crop and the treatment wise yield data of Soybean crop is summarized in Table 5-8 below.

Table 5: Effect of herbicidal compositions on total weed count (no./m2) in Soybean
No. Treatments Dose per acre Weed Population (no./m2)
Narrow leaved weeds Broad leaved weeds
15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA*
1 T1 800 mL 2.27 (4.65) 1.62 (2.15) 1.48 (1.70) 3.01 (8.54) 2.86 (7.68) 2.65 (6.55)
2 T2 1000 mL 2.20 (4.32) 1.55 (1.90) 1.36 (1.34) 2.98 (8.38) 2.79 (7.29) 2.59 (6.21)
3 T3 1200 mL 2.15 (4.13) 1.46 (1.63) 1.26 (1.10) 2.48 (5.68) 2.64 (6.50) 2.40 (5.27)
4 T4 800 mL 2.07 (3.80) 1.37 (1.40) 1.25 (1.05) 2.91 (7.96) 2.68 (6.68) 2.56 (6.05)
5 T5 1000 mL 2.01 (3.56) 1.32 (1.24) 1.24 (1.03) 2.69 (6.74) 2.65 (6.50) 2.46 (5.55)
6 T6 1200 mL 1.92 (3.20) 1.25 (1.07) 1.14 (0.81) 2.67 (6.65) 2.41 (5.30) 2.29 (4.77)
7 T7 1111 mL 2.46 (5.60) 2.19 (4.30) 2.3 (4.80) 3.93 (15.00) 4.04 (15.86) 4.78 (22.41)
8 T8 36 gm 3.03 (8.74) 3.45 (11.42) 3.63 (12.68) 3.63 (12.72) 3.75 (13.58) 4.62 (20.88)
9 T9 100 gm 3.39 (11.02) 4.55 (20.23) 6.09 (36.56) 3.39 (11.02) 3.22 (9.89) 4.14 (16.63)
10 T10 1000 mL 3.51 (11.85) 4.73 (21.85) 6.35 (39.85) 3.31 (10.45) 3.08 (9.00) 3.89 (14.66)
11 T11 -- 8.47 (71.25) 9.84 (96.23) 10.94 (119.23) 4.35 (18.50) 4.80 (22.58) 4.97 (24.23)
CD 5% - 0.14 0.12 0.10 0.14 0.15 0.13
* DAA: Days after application; CD 5%: Critical Difference; g = Gram; m2 = Square meter; mL = Millilitre; g = Gram; Values in brackets are original values and values outside brackets are transformed values.
Table 6: Effect of herbicidal compositions on total weed dry weight (g/m2) in Soybean
No. Treatments Dose per acre Weed Dry Weight (g/m2)
Narrow leaved weeds Broad leaved weeds
15 DAA* 30 DAA* 45 DAA* 15 DAA* 30 DAA* 45 DAA*
1 T1 800 mL 0.96 (0.42) 0.86 (0.24) 0.89 (0.29) 1.33 (1.28) 1.63 (2.17) 1.80 (2.75)
2 T2 1000 mL 0.91 (0.33) 0.83 (0.19) 0.83 (0.19) 1.37 (1.37) 1.59 (2.03) 1.80 (2.74)
3 T3 1200 mL 0.91 (0.32) 0.81 (0.16) 0.79 (0.13) 1.23 (1.01) 1.45 (1.60) 1.58 (2.01)
4 T4 800 mL 0.90 (0.31) 0.80 (0.14) 0.82 (0.17) 1.29 (1.16) 1.61 (2.09) 1.63 (2.17)
5 T5 1000 mL 0.79 (0.12) 0.77 (0.10) 0.78 (0.11) 1.30 (1.18) 1.59 (2.02) 1.66 (2.24)
6 T6 1200 mL 0.79 (0.12) 0.75 (0.06) 0.77 (0.10) 1.20 (0.93) 1.48 (1.70) 1.54 (1.87)
7 T7 1111 mL 1.83 (2.85) 1.55 (1.89) 1.58 (2.01) 3.47 (11.56) 3.89 (14.63) 3.96(15.20)
8 T8 36 gm 2.36 (5.09) 2.23 (4.49) 2.41 (5.32) 2.39 (5.23) 2.58 (6.15) 3.07 (8.96)
9 T9 100 gm 2.76 (7.10) 2.55 (6.01) 2.71 (6.85) 2.12 (4.01) 2.18 (4.26) 2.82 (7.45)
10 T10 1000 mL 2.58 (6.15) 2.15 (4.12) 2.37 (5.10) 1.98 (3.42) 2.10 (3.89) 2.55 (6.01)
11 T11 -- 4.84 (22.89) 5.05 (25.02) 5.39 (28.56) 4.62 (20.89) 5.84 (33.56) 6.25 (38.56)
CD 5% - 0.14 0.12 0.10 0.14 0.15 0.13
* DAA: Days after application; CD 5%: Critical Difference; g = Gram; m2 = Square meter; mL = Millilitre
Values in brackets are original values and values outside brackets are transformed values.

Table 7: Weed Control Efficacy (WCE) (%) in Soybean, of different herbicidal compositions
No. Treatments Dose per acre Weed Control Efficacy (%)
Narrow leaved weeds Broad leaved weeds
30 DAA* 45 DAA* 30 DAA* 45 DAA*
1 T1 800 mL 99.04 98.98 93.53 92.86
2 T2 1000 mL 99.24 99.33 93.95 92.89
3 T3 1200 mL 99.36 99.54 95.23 94.78
4 T4 800 mL 99.44 99.40 93.77 94.37
5 T5 1000 mL 99.60 99.61 93.98 94.19
6 T6 1200 mL 99.76 99.64 94.93 95.15
7 T7 1111 mL 92.44 92.96 56.40 60.58
8 T8 36 gm 82.04 81.37 81.67 76.76
9 T9 100 gm 75.97 76.01 87.30 80.67
10 T10 1000 mL 83.53 82.14 88.40 84.41
11 T11 -- -- --
* DAA: Days after application; g = Gram; mL = Millilitre
Table 8: Treatment wise yield of Soybean pod
Treatment Yield (q/ha)
T1 9.18
T2 9.41
T3 9.52
T4 9.26
T5 9.38
T6 9.46
T7 7.22
T8 7.36
T9 8.78
T10 8.96
T11 5.34
CD 5% 0.69
CD 5%: Critical Difference, q/ha = quintal/hectare
Data presented in table 5 shows that weed population was significantly affected by all the treatments against control when observed at 15, 30 and 45 days after application (DAA). At 45 DAA a composition comprising Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.6%, and Imazethapyr 10% SC and a composition comprising Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.9% and Imazethapyr 10% SC @ all the doses recorded lowest weed population closely followed by T10 and T9. Similar results were observed in case of Weed dry weight (Table 6) and WCE (Table 7).
Highest pod yield of 9.52 and 9.46 q/ha was recorded on treatment with a composition comprising Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.6% and Imazethapyr 10% SC and a composition comprising Fenoxaprop-p-Ethyl 6%, Chlorimuron Ethyl 0.9% and Imazethapyr 10% SC @ dose of 1200 mL/ha.
Phytotoxic effect of herbicidal compositions on soybean crop
Visual observations on phytotoxicity were recorded for leaf injury on tip/surface, Epinasty/Hyponasty, and wilting, etc. on 0-10 scale (Table 9) at 1, 3, 7, 14 and 21 days after application (DAA) and the average values are presented in table 10.
Table 9. 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 10: Phytotoxicity of herbicidal compositions on Soybean crop
No. Treatments Dose (mL/ha) Phytotoxicity (Days after Application)
1 3 7 14 21
1 Fenoxaprop-p-Ethyl 6% + Chlorimuron Ethyl 0.6% + Imazethapyr 10% SC 1000 0 0 0 0 0
2 2000 0 0 0 0 0
3 4000 0 0 0 0 0
4 Fenoxaprop-p-Ethyl 6% + Chlorimuron Ethyl 0.9% + Imazethapyr 10% SC 1000 0 0 0 0 0
5 2000 0 0 0 0 0
6 4000 0 0 0 0 0
7 Control - 0 0 0 0 0
0= No Phytoxicity
It is evident from the Table 10 above that the synergistic herbicidal composition comprising Fenoxaprop Ethyl, Chlorimuron Ethyl and Imazethapyr did not show any phytotoxicity when applied to soybean crop.
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) a aryloxyphenoxypropionic ester; (b) at least two acetolactate synthase (ALS) inhibitors; and (c) 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 1-3, wherein the ALS inhibitors are 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 1-4, wherein the ALS inhibitors are Chlorimuron ethyl and Imazethapyr.
6. The synergistic herbicidal composition as claimed in claims 4 and 5, wherein Fenoxaprop-p-ethyl, Chlorimuron ethyl and Imazethapyr are present in a ratio ranging from 1.00:0.10:1.67 to 1.00:0.15:1.67.
7. The synergistic herbicidal composition, as claimed in claims 4, 5 and 6, wherein Fenoxaprop-p-ethyl is present in an amount of 6%, Imazethapyr is present in an amount of 10% and Chlorimuron ethyl is present in an amount in the range from 0.60 to 0.90%.
8. The synergistic herbicidal composition, as claimed in claims 1 to 7, wherein the composition may be in the form of a suspension concentrate (SC), soluble granules (SG) or soluble liquid (SL).
9. The synergistic herbicidal composition, as claimed in claims 1 to 8, wherein the additives are selected from the group consisting of anti-freezing agent, dispersing cum wetting agent, defoamer, biocide, thickener, water and combinations thereof, and the composition is in the form of a suspension concentrate (SC).
10. 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 (DEG), mono-ethylene glycol (MEG) and combinations thereof, and present in an amount in the range from 1.00-8.00% and preferably 5%.
11. The synergistic herbicidal composition, as claimed in claim 9, wherein the dispersing cum wetting agent is selected from the group consisting of mixture of non-ionic surfactants and amine salt of phosphate tristyryl phenol ethylated, acrylic copolymer, ethoxylated polyarylphenol phosphate ester and combinations thereof, and present in an amount in the range from 2.00-10.00%.
12. 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 0.01-0.50%, and preferably 0.20%.
13. The synergistic herbicidal composition, as claimed in claim 9, wherein the biocide is selected from Proxel GXL or formaldehyde and present in an amount in the range from 0.01-0.50%, and preferably 0.20%.
14. The synergistic herbicidal composition, as claimed in claim 9, wherein the thickener is Xanthan gum and present in an amount in the range from 0.10-0.50%, and preferably 0.20%.
15. The synergistic herbicidal composition, as claimed in any of the claims 1 to 14, wherein said composition is non-phytotoxic.