GB2621169A

GB2621169A - Herbicidal composition and use thereof

Info

Publication number: GB2621169A
Application number: GB2211429.2A
Authority: GB
Inventors: Timothy Bristow James
Original assignee: Rotam Agrochem International Co Ltd
Current assignee: Rotam Agrochem International Co Ltd
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2024-02-07
Also published as: GB202211429D0

Abstract

Herbicidal composition in the form of an emulsifiable concentrate is provided, the herbicidal composition comprising a) pinoxaden; b) a carbodiimide of general formula I (R – N = C = N – R1 (I), wherein R and R1 are each independently an aliphatic or aromatic group) c) at least one solvent; and d) at least one emulsifier. Preferably, the carbodiimide is one of DIC, EDC, DCC, diphenylcarbodiimide or 2,6-diisopropylphenylcarbodimide. The carbodiimide may be present in 0.2 to 3 wt.%. Pinoxaden may be present at 5 to 25 % by weight. The EC may further comprise further herbicides and/or a safener (e.g. cloquintocet-mexyl). Also claimed is a method of controlling unwanted plant growth at a locus, comprising applying to the locus a composition described supra. Further claimed is the use of a carbodiimide of general formula I to increase the stability of pinoxaden in a herbicidal composition. Additionally claimed is a method for increasing the stability of pinoxaden in a herbicidal composition.

Description

HERBICIDAL COMPOSITION AND USE THEREOF

The present invention relates to a herbicidal composition comprising pinoxaden as a herbicidally active compound. The present invention further relates to the use of the herbicidal composition for controlling unwanted plant growth, such as weeds in crops.

[8-(2,6-diethyl-4-methyl phenyI)-1,2,4,5-tetrahydro-7-oxo-7H-pyrazolo[1, 2-d][1,4,5]oxadiazepin-9-y1-2,2-dimethylpropionate, a known herbicidally active compound, has the Chinese name zuolincaozhi, with the English common name being pinoxaden. Pinoxaden and its preparation are known in the art, for example from WO 99/47525 Al. Pinoxaden has the following structural formula: Formulations of pinoxaden are available commercially. For example, emulsifiable concentrates (EC) of pinoxaden are available from Syngenta in many countries; for example, in the United States, they are available under the trademarks AxialTM and Axial XLTM.

EP 1062217 discloses formulations of pinoxaden. Example Fl of EP1062217 describes an emulsifiable concentrate of pinoxaden. However, such emulsifiable concentrates have a poor stability. In particular, after a period of time, the active substance pinoxaden is decomposed or modified, such as by hydrolysis or transesterification. This problem with emulsifiable concentrate formulations of pinoxaden is known in the art and a number of solutions to this problem have been proposed.

CN 101453894 discloses including an alcohol as a solvent in a pinoxadencontaining emulsifiable concentrate to improve the storage stability of the active substance pinoxaden.

AU 2019100546 teaches the use of a combination of at least two of the solvents acetophenone, propylene carbonate, butylene carbonate, and N-(C1-C4)alkylpyrrolidone to improve the stability of the active substance pinoxaden in a pinoxaden emulsifiable concentrate.

CN 101562978 discloses a liquid composition comprising pinoxaden and a phosphoric acid triester of an aliphatic or aromatic alcohol and/or an alkylphosphate of an aliphatic or aromatic alcohol. Example 1 of CN 101562978 discloses a pinoxaden emulsifiable concentrate incorporating tris-(2-ethylhexyl) phosphate, which enhances the stability of pinoxaden in the formulation.

Although the formulations suggested in the prior art can reduce the thermal degradation rate of a pinoxaden emulsifiable concentrate, the thermal stability of pinoxaden at elevated temperatures, for example at 60 or 70°C is still poor.

Therefore, there remains a pressing need to imrove the stability of a pinoxaden emulsifiable concentrate formulation.

It has unexpectedly been found that the addition of a carbodiimide to a pinoxaden emulsifiable concentrate can significantly improve the stability of the active substance pinoxaden, in particular the long term storage stability of the formulation.

Therefore, in a first aspect, the present invention provides a herbicidal composition in the form of an emulsifiable concentrate, the herbicidal composition comprising a) pinoxaden; b) a carbodiimide of general formula I: R-N=C=N-R1 (I) wherein R and R' are each independently an aliphatic or aromatic group; c) at least one solvent-and d) at least one emulsifier.

In the herbicidal composition according to the present invention, the presence of the carbodiimide of formula I unexpectedly leads to a significantly increased stability of the pinoxaden emulsifiable concentrate. Unexpectedly, little to no hydrolysis or transesterification of the pinoxaden active compound is observed in the herbicidal composition.

The composition comprises pinoxaden as an active herbicidal component. Pinoxaden may be present in any suitable amount to provide the required activity and/or application rate during end use. Pinoxaden may be present in an amount of from 0.5% by weight, preferably from 1%, more preferably from 2%, still more preferably from 3%, more preferably still from 4%, especially from 5% by weight of the composition. Pinoxaden may be present in an amount of up to 60% by weight, preferably up to 50%, more preferably up to 40%, still more preferably up to 35%, more preferably still up to 30%, especially up to 25% by weight of the composition. Pinoxaden may be present in an amount of from 1 to 50% by weight, preferably from 3 to 40% by weight, more preferably from 5 to 25% by weight of the composition.

The composition of the present invention further comprises a carbodiimide of formula I: R-N=C=N-R1 (I) R and R1 may each be selected from aliphatic groups, including straight chain, branched chain or cyclic aliphatic groups. Suitable aliphatic groups include those having from 1 to 10 carbon atoms, preferably from 1 to 8, more preferably from 1 to 7, still more preferably from 1 to 6, especially from 1 to 5, more especially from 1 to 4 carbon atoms.

The aliphatic groups may be saturated or unsaturated.

Examples of suitable aliphatic groups for R and R1 include methyl, ethyl, ethenyl, propyl, propenyl, butyl, butenyl, pentyl, pentenyl, hexyl and hexenyl. Preferrred aliphatic groups include methyl, isopropyl, propenyl and cyclohexyl.

R and R1 may each be selected from aromatic groups. Suitable aromatic groups include phenyl and naphthyl groups. The aromatic groups may comprise an aromatic ring bearing one or more subsfituents, such as alkyl, alkylamino and halogen moieties. Examples of suitable aromatic groups include phenyl, o-methylphenyl, pmethylaminophenyl, p-bromophenyl and naphthyl. Phenyl is a preferred aromatic group for one or both of R and R1.

Each of the groups represented by R and R1 may be substituted with one or more substituents. Substituents may each independently be halogen, amino, alkylamino, sulfonic acid group, amido, carboxyl, alkyl, substituted alkyl, ester group, ether group, aryl, or substituted aryl.

The carbodiimides of formula I can be divided into symmetrical, that is where R and R1 are the same moiety, and asymmetric carbodiimides, that is where R and R1 represent different moieties. For many embodiments, symmetrical carbodiimides of formula I are preferred.

Examples of preferred carbodiimides of formula I are dimethylcarbodiimide, diisopropylcarbodiimide (DIG), di-tert-butylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), dicyclohexylcarbodiimide (DCC), diphenylcarbodiimide and 2,6-diisopropylphenylcarbodiimide.

Dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIG), 1-ethyl-(3- dimethylaminopropyl)carbodiimide (EDC), diphenylcarbodiimide, and 2,6-diisopropylphenylcarbodiimide are particularly preferred carbodiimides.

Dicyclohexylcarbodiimide (DCC), 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), and diisopropylcarbodiimide (DIG) are especially preferred carbodiimides.

The composition may comprise a single carbodiimide or two or more carbodiimides of formula I. The carbodiimide may be present in any suitable amount to provide the required level of stability of pinoxaden. This amount is a so-called 'stabilising amount'. The carbodiimide may be present in an amount of from 0.01% by weight, preferably from 0.03%, more preferably from 0.05%, still more preferably from 0.1%, more preferably still from 0.15%, especially from 0.2% by weight of the composition. The carbodiimide may be present in an amount of up to 15% by weight, preferably up to 12%, more preferably up to 10%, still more preferably up to 8%, more preferably still up to 6%, especially up to 5%, more especially up to 4%, still more especially up to 3% by weight of the composition. The carbodiimide may be present in an amount of from 0.01 to 10% by weight, preferably from 0.05 to 8% by weight, more preferably from 0.1 to 5%, especially from 0.2 to 3% by weight of the composition.

The composition further comprises one or more solvents. Any solvent suitable for forming an emulsifiable concentrate formulation containing pinoxaden as the active ingredient may be used. Preferred solvents include: ketones, such as cyclohexanone, acetophenone, butanone, methyl-n-amyl ketone, 4-hydroxyl-4-methyl-2-pentanone, and methyl isobutyl ketone; amides, such as N,N-dimethyldecanamide, N,Ndimethyloctanamide, and N,N-dimethyldecenamide; cyclic compounds, such as Nmethyl-pyrrolidone, N-octyl-pyrrolidone, N-dodecyl-pyrrolidone, N-octyl-caprolactam, Ndodecyl-caprolactam, and y-butyrolactone; benzoate solvents, such as benzyl benzoate, methyl benzoate, and dipropylene glycol dibenzoate; lower alkyl esters of higher fatty acids, such as Cg to Clo fatty acid methyl esters and C16 to C15 fatty acid methyl esters; aromatic hydrocarbon solvents, such as toluene, xylene, cumene, and aromatic solvent blends, such as the commercially available solvents Solvesso 100, Solvesso 150, and Solvesso 200; esters, such as propylene glycol monomethyl ether acetate, dibutyl adipate, ethyl acetate, heptyl acetate, tri-n-butyl citrate, and di-n-butyl phthalate; alcohols, such as Ci to C12 alkanols, for example methanol, ethanol, propanol, butanol, hexanol, octanol and dodecanol, wherein the alcohols may be linear or branched, for example isobutanol, isoamyl alcohol, 2-ethylhexanol and isotridecanol, substituted alcohols, such as furfuryl and tetrahydrofurfuryl alcohols, aromatic alcohols, such as benzyl alcohol, cyclic alcohols, preferably cyclopentanol and cyclohexanol; diols or triols, such as ethylene glycol, propylene glycol, 1-methoxy-2-dipropanol, dipropylene glycol ether, and 2-methyl-2,4-pentanediol; glycol monoethers, such as ethylene glycol butyl ether and diethylene glycol butyl ether; and lactates, such as alkyl lactate, ethyl lactate and butyl lactate.

The solvent may be present in any suitable amount to provide a solution of the components. The solvent may be present in an amount of from 0.1% by weight, preferably from 1%, more preferably from 5%, still more preferably from 10%, more preferably still from 15%, especially from 20% by weight of the composition. The solvent may be present in an amount of up to 95% by weight, preferably up to 90%, more preferably up to 85%, still more preferably up to 80%, more preferably still up to 75%, especially up to 70%, more especially up to 65%, still more especially up to 60% by weight of the composition. The solvent may be present in an amount of from 0.1 to 95% by weight, preferably from 10 to 80% by weight, more preferably from 20 to 60% by weight of the composition.

The composition further comprises one or more emulsifiers. Any emulsifier suitable for preparing a concentrate of pinoxaden that may be readily dispersed as an emulsion in water may be used. Suitable emulsifiers may be selected from castor oil-alkylene oxide addition products (condensation products), particularly castor oil ethoxylates, which can have varying amounts of ethoxylafion, for example castor oil ethoxylates (20 to 50 EO) (that is, containing 20 to 50 moles of ethylene oxide (EO) per mole of castor oil or produced therefrom) or more preferably castor oil ethoxylates (30 to 44 EC); alcohol-alkylene oxide addition products (condensation products), particularly Ci to C22 alcohol-alkylene oxide addition products, such as C8 to 022 alcohol ethoxylates (which may have varying amounts of ethoxylation), such as tridecanol ethoxylate; alkylphenolalkylene oxide addition products (condensation products), such as nonylphenol ethoxylates; sorbitol esters, such as sorbitan oleate; polyethylene glycol esters of Ca to C22 fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide (EO) and propylene oxide (PO); butanol ethylene oxide (E0)/propylene oxide (PO) copolymers, methyl ethylene oxide polymers with ethylene oxide and monobutyl ether, such as Atlas G5000DTM butanol EO/PO copolymers (available from CRODA); salts of Ci to 022 alkyl-phenyl-sulfonates, for example alkaline earth metal salts, such as calcium salts, including salts of C8 to C18 alkyl-phenyl-sulfonates, such as calcium dodecylbenzenesulfonate; di-Ci-C22 alkyl esters of sulfosuccinates, such as sodium bis(2-ethylhexyl)sulfosuccinate, or salts of mono-and/or di-alkyl phosphates; or mixtures of two or more of these emulsifiers.

Alternatively or additionally, one or more other emulsifiers may be used, preferably tristyrylphenol alkoxylates, such as tristyrylphenol ethoxylates and/or tristyrylphenol ethoxylate-propoxylates, more particularly tristyrylphenol ethoxylates containing 8 to 30, more preferably 10 to 25 moles of ethylene oxide (ED) per mole of tristyrylphenol, for example Soprophor TS/10Tm (10 moles of ED), Soprophor BSUTM (16 moles of ED) or Soprophor S/25TM (25 moles of EC), wherein all SoprophorTM tristyrylphenol alkoxylates are available from Rhodia.

Preferably, the emulsifier is a castor oil-alkylene oxide addition product (a condensation product), more preferably a castor oil ethoxylate, especially having 20 to 50 ED, more especially 30 to 44 ED (that is containing 20 to 50, preferably 30 to 44 moles of ethylene oxide (ED) per mole of castor oil or produced therefrom).

The emulsifier may be present in any suitable amount to provide a readily dispersible solution of the components. The emulsifier may be present in an amount of from 0.1% by weight, preferably from 0.5%, more preferably from 0.75%, still more preferably from 1%, more preferably still from 1.5%, especially from 2%, more especially from 3% by weight of the composition. The emulsifier may be present in an amount of up to 40% by weight, preferably up to 35%, more preferably up to 30%, still more preferably up to 25%, more preferably still up to 20%, especially up to 15%, more especially up to 10%, still more especially up to 8% by weight of the composition. The emulsifier may be present in an amount of from 0.1 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 2 to 15% by weight of the composition.

In one preferred embodiment, the emulsifier comprises a castor oil-alkylene oxide addition product, preferably present in an amount of from 1% to 15%, more preferably from 2% to 10%, still more preferably from 3% to 8% by weight.

The composition may further comprise a safener. Any suitable safener for pinoxaden may be used. Preferred safeners include cloquintocet-mexyl, mefenpyr-diethyl or isoxadifen-ethyl and derivatives thereof, such as the corresponding acids and

B

salts. Such safeners are known in the art and described, for example, in The Pesticide Manual, 12th edition, BCPC and DE 43 31 448.

In addition to the herbicide pinoxaden, the composition of the present invention may comprise one or more other herbicides which are compatible therewith. "Compatible" as used herein means that the herbicidal composition is chemically stable and the one or more further herbicides neither exhibit an antagonistic action nor increase phytotoxicity to useful plants.

Such further herbicides are preferably selected from sulfonylureas, such as triasulfuron, tribenuron, metsulfuron, thifensulfuron, flupyrsulfuron, chlorsulfuron, prosulfuron, amidosulfuron, mesosulfuron, sulfosulfuron and tritosulfuron; aryloxyphenoxypropionates and heteroaryloxyphenoxypropionates, such as clodinafoppropargyl, fenoxaprop-P-ethyl, diclofop-methyl and cyhalofop-butyl; triazolylpyrimidines, such as florasulam, metosulam and flumetsulam; arylcarboxylic acids, preferably dicamba and clopyralid; aryloxycarboxylic acids, preferably 2,4-D ester, 2,4-DP, mecoprop, mecoprop-P, MCPA, MCPB, dichlorprop-P and fluroxypyr; cyclohexanedione oximes, such as tralkoxydim; thiocarbamates, such as triallate and prosulfocarb; hydroxybenzonitriles, such as bromoxynil, bromoxynil octanoate, ioxynil and ioxynil octanoate; dinitroanilines, such as pendimethalin and trifluralin; and pyridinecarboxamides, such as diflufenican.

The composition may optionally comprise one or more additional formulation auxiliaries. The use of such auxiliaries is known in the art. Such auxiliaries include, for example, crystallization inhibitors, viscosity modifyiers, suspending agents, dyes, antioxidants, defoamers, opacifiers, pH adjusters, colorants, wetting agents, synergists, micronutrients, dispersants, antifreeze agents, microbicides and fertilizers.

The composition of the present invention may be prepared using methods and techniques known in the art for preparing emulsifiable concentrate formulations. A preferred preparation method is as follows: first, one or more carbodiimides and a solvent are added to a compounding vessel, such as a compounding kettle with hot water circulation; the active substance pinoxaden and optionally other herbicides are then added to the compounding vessel with stirring; stirring is continued until all the active components are completely dissolved; additional formulating agents, such as an emulsifier, are then added; and stirring is continued until complete homogeneity of the mixture is achieved.

Still further, the present invention provides a method for controlling unwanted plant growth, the method comprising applying to the plant or a growing environment thereof a herbicidally effective amount of the herbicidal composition as hereinbefore described.

In a further aspect, the present invention provides the use of a herbicidal composition as hereinbefore described in the control of unwanted plant growth.

The composition of the present invention can be used for controlling unwanted plant growth, for example unwanted plant growth in a wide range of crop plants. The composition is especially suited for use with crops of cereals, cotton, soybeans, sugar beets, sugar cane, plantation plants, oilseed rape, maize and rice. The composition is especially suited for use in maize and cereal crops, and for the non-selective control of weeds. The composition is especially suited for use with crops of grains, in particular wheat, triticale, rye and barley crops.

The composition may be used to control the growth of a wide range of unwanted plants. Examples of such unwanted plants include monocotyledonous and dicotyledonous weeds. Specific examples of plants that may be controlled using the composition are the genera Ste Apera, Avena, Setaria, Sinapis, Lolium, Echinochloa, Bromus, Alopecurus, Phalaris, Amaranthus, Chenopodium, Convolvulus, Chrysanthemum, Papaver, Cirsium, Polygonum, Matricaria, Gal/urn, Viola, and Veronica.

As discussed above, it has been found that a carbodiimide of formula I is effective in significantly improving the stability of pinoxaden, for example in an emulsifiable concentrate formulation.

Therefore, in a further aspect, the present invention provides the use of a carbodiimide of formula I to increase the stability of pinoxaden in a herbicidal composition.

Still further, there is provided a method for increasing the stability of pinoxaden in a herbicidal composition, the method comprising including in the composition a carbodiimide of formula I. Embodiments of the present invention will now be described, for illustrative purposes, by way of the following working examples.

Percentages are % weight, unless otherwise indicated.

EXAMPLES

In the examples, the following commercially available components were employed: Atlas G-5000: a VOC-free, NPE-free nonionic polyalkylene glycol ether (emulsifier, ex. Croda); Soprophor TS/10: a nonionic tristyryphenol (emulsifier, ex. Solvay); Rhodacal 60/B-E: a calcium dodecylbenzene sulfonate (emulsifier, ex. SoIvey); SOLVESS0150® ND: a naphthalene-depleted C10 aromatic fluid (solvent, ex. Exxon); SOLVESSO 200® ND: a naphthalene-depleted Cii aromatic fluid (solvent, ex. Exxon); Termul 3150: a tristyrylphenol polyoxyethylene ether (emulsifier, ex. Huntsman); and Termul 200: a ethylene oxide propylene oxide monononylphenol ether (emulsifier, ex. Huntsman).

Example 1

An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden Cloguintocet-mexyl Atlas G-5000 Soprophor TS/10 Rhodacal 60/B-E Tetrahydrofurfuryl alcohol Dicyclohexylcarbodiimide (DCC) SOLVESSO 200® ND 105 g 27 g 20 g 15 g 10 g 300 g 10 g making up to 1 L

Example 2

An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 50 g Cloguintocet-mexyl 12.5 g Castor oil ethoxylate (30 EO) 40 g Calcium alkylbenzenesulfonate 20 g Tris-(2-ethylhexyl)phosphate 300 g Tetrahydrofurfuryl alcohol 180 g Diisopropylcarbodiimide (DIC) 5 g SOLVESSO 200® ND making up to 1 L

Example 3

An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden Cloquintocet-mexyl Termul 3150 Termul 200 N-methylpyrrolidone Acetophenone 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) SOLVESSO 200® g g 80g g g g g making up to 1 L

Example 4

An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden Mefenpyr-diethyl Calcium dodecylbenzenesulfonate Castor oil ethoxylate (20 EC) 2-methyl-2,4-pentanediol Diphenylcarbodiimide SOLVESS0150® ND g 50 g 40 g 60 g 380 g 25 g making up to 1 L

Example 5

An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 250 g 2,6-Diisopropylphenylcarbodiimide 30 g Tristyrylphenol polyoxyethylene ether 30 g Castor oil ethoxylate 30 g N,N-dimethyldecanamide 300 g Methyl oleate making up to 1 L Comparative Example 1 An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 105 g Cloquintocet-mexyl 27 g Atlas G-5000 20 g Soprophor TS/10 15 g Rhodacal 60/B-E 10 g Tetrahydrofurfuryl alcohol 300 g SOLVESSO 200® ND making up to 1 L Comparative Example 2 An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 50 g Cloquintocet-mexyl 12.59 Castor oil ethoxylate (30 EO) 40 g Calcium alkylbenzenesulfonate 20 g Tris-(2-ethylhexyl)phosphate 300 g Tetrahydrofurfuryl alcohol 180 g SOLVESSO 200® ND making up to 1 L Comparative Example 3 An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 105 g Cloguintocet-mexyl 25 g Termul 3150 80 g Termul 200 20 g N-methylpyrrolidone 100 g Acetophenone 100 g SOLVESSO 200® ND making up to 1 L Comparative Example 4 An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden Mefenpyr-diethyl Calcium dodecylbenzenesulfonate Castor oil ethoxylate (20 EC) 2-methyl-2,4-pentanediol SOLVESS0150® ND g 50 g 40 g 60 g 380 g making up to 1 L Comparative Example 5 An emulsifiable concentrate (EC) formulation was prepared by combining the following components with stirring: Pinoxaden 2,6-Diisopropylphenylcarbodiimide Tristyrylphenol polyoxyethylene ether Castor oil ethoxylate N,N-dimethyldecanamide Methyl oleate 250 g 30 g 30 g 30 g 300 g making up to 1 L Thermal Storage Stability Test Samples of the compositions of Examples 1 to 5 and Comparative Examples 1 to 5 were stored in an oven at 60°C for 2 weeks. The content (g/L) of pinoxaden before and after storage was measured, and the loss rate (%) was calculated.

The results are shown in Table 1 below.

Table 1

Pinoxaden Pinoxaden Degradation (0/0) content before content after storage storage (g/L) (g/L) Example 1 102.3 101.1 1.17 Example 2 50.1 49.6 1.00 Example 3 103.5 101.9 1.55 Example 4 199.4 196.9 1.25 Example 5 249.2 244.9 1.73 Comparative Example 1 102.6 95.31 7.11 Comparative Example 2 49.8 46.4 6.83 Comparative Example 3 102.2 91.01 10.95 Comparative 200.6 185.83 7.36

Example 4

Comparative 250.1 202.56 19.01

Example 5

The data in Table 1 show that the use of a carbodiimide resulted in a significantly more stable formulation, with a significant reduction in the loss of pinoxaden during the storage period.

Biological Example

The herbicidal activity of the emulsifiable concentrate of the present invention was tested using the following procedure: Monocotyledonous and dicotyledonous weeds, in particular Alopecurus myrosuroides, Sclerochloa, Avena fatua, Polypogon fugax Nees ex Steud, and Lofium perenne, were cultivated in standard soil in plastic pots at room temperature. The composition of Example 1 was diluted in water to form a stable emulsion and applied to the plants at the 3 to 6 leaf stage of growth at a range of different application rates, indicated in Table 2 below.

The effect of the treatment on the plants was evaluated after 20 days. The effect on the plants was rated according to the scale: 100% = plant death; and 0% = no toxic effect on the plant.

The results are shown in Table 2 below:

Table 2

Test plant Weed control (°/0) at application rate (g ai/ha) Composition of Example 1 8 16 64 Alopecurus 73 82 100 myrosuroides Sclerochloa 78 95 100 Avena fatua 90 96 100 Polypogon fugax 75 98 100 Nees ex Steud Lolium perenne 100 100 100 As can be seen from the results in Table 2, the compositions of the present invention exhibit a high level of activity in the control of unwanted plant growth.

Claims

CLAIMS1. A herbicidal composition in the form of an emulsifiable concentrate, the herbicidal composition comprising a) pinoxaden; b) a carbodiimide of general formula I: R-N=C=N-121 (I) wherein R and R1 are each independently an aliphatic or aromatic group; c) at least one solvent; and d) at least one emulsifier.
2. The herbicidal composition according to claim 1, wherein one or both of R and 51 independently represent an aliphatic group having from 1 to 10 carbon atoms.
3. The herbicidal composition according to claim 2, wherein one or both of R and R1 independently represent an aliphatic group selected from methyl, ethyl, ethenyl, propyl, propenyl, butyl, butenyl, pentyl, pentenyl, hexyl and hexenyl.
4. The herbicidal composition according to any preceding claim, wherein one or both of R and R1 independently represent an aromatic group selected from phenyl and naphthyl groups.
5. The herbicidal composition according to claim 4, wherein one or both of of R and R1 independently represent an aromatic group selected from phenyl, o-methylphenyl, pmethylaminophenyl, p-bromophenyl and naphthyl.
6. The herbicidal composition according to any preceding claim, wherein the carbodiimide of the general formula I is selected from dimethylcarbodiimide, diisopropylcarbodiimide (DIC), di-tert-butylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), dicyclohexylcarbodiimide (DCC), diphenylcarbodiimide and 2,6-diisopropylphenylcarbodiimide.
7. The herbicidal composition according to any preceding claim, wherein the carbodiimide of general formula I is present in the composition in an amount of from 0.01 to 10% by weight.
8. The herbicidal composition according to claim, wherein the carbodiimide is present in the composition in an amount of from 0.2 to 3% by weight of the composition.
9. The herbicidal composition according to any preceding claim, wherein pinoxaden is present in the composition in an amount of from 1 to 50% by weight.
10. The herbicidal composition according to claim 9, wherein pinoxaden is present in the composition in an amount of from 5 to 25% by weight.
11. The herbicidal composition according to any preceding claim, wherein the solvent is selected from a ketone, an amide, a cyclic compound, a benzoate, a lower alkyl ester of a higher fatty acid, an aromatic hydrocarbon solvent, an ester, an alcohol, a glycol monoether, a lactate and mixtures thereof.
12. The herbicidal composition according to claim 11, wherein the solvent comprises an alcohol selected from propanol, hexanol, octanol, dodecanol, 2-ethylhexanol, isotridecanol, dipropylene glycol ether, 2-methyl-2,4-pentanediol, furfuryl alcohol, tetrahydrofurfuryl alcohol, benzyl alcohol, 4-hydroxyl-4-methyl-2-pentanone, cyclopentanol, and cyclohexanol.
13. The herbicidal composition according to either of claims 11 or 12, wherein the solvent comprises an aromatic hydrocarbon solvent selected from toluene, xylene, cumene and blends of aromatic sovents.
14. The herbicidal composition according to any of claims 11 to 13, wherein the solvent comprises a ketone selected form cyclohexanone, acetophenone, butanone, methyl-namyl ketone, and methyl isobutyl ketone.
15. The herbicidal composition according to any of claims 11 to 14, wherein the solvent comprises an amide solvent selected from N,N-dimethyldecanamide, N,Ndimethyloctanamide, and N,N-dimethyldecenamide.
16. The herbicidal composition according to any preceding claim, wherein the composition comprises one or more further herbicides.
17. The herbicidal composition according to claim 16, wherein the one or more further herbicides are each selected from sulfonylureas, aryloxyphenoxypropionates, triazolopyrimidines, arylcarboxylic acids, aryloxycarboxylic acids, heteroaryloxycarboxylic acids, cyclohexanedione oximes, thiocarbamates, hydroxybenzonitriles, dinitroanilines and pyridinecarboxamides.
18. The herbicidal composition according to any preceding claim, further comprising a safener.
19. The herbicidal composition according to claim 18, wherein the safener is selected from cloquintocet-mexyl, mefenpyr-diethyl, isoxadifen-ethyl and derivatives thereof.
20. The herbicidal composition according to any preceding claim, wherein the emulsifier is selected from an alkyl sulfonate, a vegetable oil alkoxylate, an alkylphenol epoxide, an ethylene oxide and propylene oxide block copolymer, and mixtures thereof.
21. A method of controlling unwanted plant growth at a locus, the method comprising applying to the locus a composition according to any preceding claim.
22. The use of a composition according to any of claims 1 to 20 in the control of plant growth.
23. The use of a carbodiimide of general formula I: R-N=C=N-R1 (I) wherein R and R1 are each independently an aliphatic or aromatic group, to increase the stability of pinoxaden in a herbicidal composition.
24. A method for increasing the stability of pinoxaden in a herbicidal composition, the method comprising including in the composition a carbodiimide of general formula I: R-N=C=N-R' (I) wherein R and R1 are each independently an aliphatic or aromatic group.