WO2008150869A2

WO2008150869A2 - Herbicidal composition

Info

Publication number: WO2008150869A2
Application number: PCT/US2008/065087
Authority: WO
Inventors: James T. Bahr; Thomas E. Hashman; James E. Lappin; Kim G. Watson
Original assignee: Fmc Corporation
Priority date: 2007-05-30
Filing date: 2008-05-29
Publication date: 2008-12-11
Also published as: WO2008150869A3

Abstract

The present invention provides an herbicidal composition comprising a first herbicide and a second herbicide in which the first herbicide is 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl-2,4( 1 H,3H) pyrimidinedione and the second herbicide is a 4-hydroxyphenyl-pyruvate-dioxygenase (4-HPPD) inhibitor compound, and an herbicidal method of use thereof.

Description

HERBICIDAL COMPOSITION CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No.

60/932,225, filed May 30, 2007.

FIELD OF THE INVENTION

This invention relates to herbicidal compositions containing 3-(4-chloro-6- fluoro-2-trifluoromethyl-benzimidazol-7-yl)-l-methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione and a 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound.

BACKGROUND OF THE INVENTION

U. S. Patent 6,077,812 discloses 3-(4-chloro-6-fluoro-2-trifruoromethyl- benzimidazol-7-yl)-l-methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione. SUMMARY OF THE INVENTION

In accordance with the present invention, it has been found that an herbicidal composition comprising a first herbicide and a second herbicide in which the first herbicide is 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)-l-methyl-6- trifluoromethyl-2,4(lH,3H)pyrimidinedione and the second herbicide is a 4- hydroxyphenyl-pyruvate-dioxygenase inhibitor compound, wherein the first herbicide and the second herbicide are present in an herbicidally effective amount, has unexpected advantageous properties over the individual components.

DETAILED DESCRIPTION OF THE INVENTION It has been unexpectedly found that an herbicidal composition comprising a first herbicide and a second herbicide in which the first herbicide is 3-(4-chloro-6- fluoro-2-trifluoromethylbenzimidazol-7-yl)-l-methyl-6-trifluoromethyl-2,4(lH,3H) pyrimidinedione and the second herbicide is a 4-hydroxyphenyl-pyruvate- dioxygenase (4-HPPD) inhibitor compound, has unexpected advantageous properties in weed control over the individual components, for example, the mixture controls a broader variety of weeds at lower rates than either component alone. The combination can also be useful in overcoming reduced sensitivity by a weed to either of the individual components.

The structural formula for 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione is as follows:

The terms "weed" and "weeds" refer to any unwanted vegetation in agricultural crops and orchards, as well as, but not limited to, around buildings, along fences, roadways and rail lines. The 4-HPPD inhibitor compound is an herbicide selected from the group consisting of mesotrione (2-[4-(methylsulfonyl)-2- nitrobenzoyl]-l,3-cyclohexanedione), isoxaflutole ([5-cyclopropyl-4-(2- methylsulfonyl-4-trifluoromethylbenzoyl)isoxazole]), sulcotrione (2-[2-chloro-4- (methylsulfonyl)benzoyl]-l,3-cyclohexanedione), topramezone ([3-(4,5-dihydro-3- isoxazolyl)-2-methyl-4-(methylsulfonyl)phenyl](5-hydroxy-l-methyl-lH-pyrazol-4- yl)methanone), tembotrione (2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2- trifluoroethoxy)methyl]benzoyl]-l,3-cyclohexanedione), benzofenap (2-[[4-(2,4- dichloro-3-methylbenzoyl)-l,3-dimethyl-lH-pyrazol-5-yl]oxy]-l-(4- methylphenyl)ethanone), pyrazolynate ((2,4-dichlorophenyl)[l,3-dimethyl-5-[[(4- methylphenyl)sulfonyl]oxy]- lH-pyrazol-4-yl]methanone), pyrazoxyfen ((2-[[4-(2,4- dichlorobenzoyl)-l,3-dimethyl-lH-pyrazol-5-yl]oxy]-l-phenylethanone), pyrasulfotole ((5-hydroxy-l,3-dimethyl-lH-pyrazol-4-yl)[2-(methylsulfonyl)-4- (trifluoromethyl)phenyl]methanone) and tefuryltrione (2-[2-chloro-4- (methylsulfonyl)-3-[[tetrahydro-2-furanyl)methoxy]methyl]benzoyl]-l,3- cyclohexanedione. The ratio of 3 -(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 - methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione to the 4-hydroxyphenyl- pyruvate-dioxygenase inhibitor compound varies over a wide range but is usually in the range of 1:0.1 to 1 :40, preferably 1 :0.3 to 1: 10.

Other herbicides can be employed in conjunction with the first and second herbicides described above providing they do not adversely affect the interaction between the components of this invention. For example it can sometimes be useful to include additional herbicides to extend the range of activity in order to control a wider spectrum of weeds. Further there is provided a method of use of an herbicidal composition comprising 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)-l-methyl-6- trifluoromethyl-2,4(lH,3H)pyrimidinedione and a 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound for controlling weeds. Another embodiment of the present invention is a method for controlling broadleaf and grass weeds in crops such as corn which comprises applying an herbicidally effective amount of a composition comprising 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione and a 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound, either together or sequentially, to a locus where weeds are present or are expected to be present.

The compositions of the present invention may be employed in many forms and are often most conveniently prepared in aqueous form immediately prior to use. One method of preparing such a composition is referred to as "tank mixing" in which the ingredients in their commercially available form are mixed together by the user in a quantity of water.

In addition to tank mixing immediately prior to use, the compositions containing 3-(4-chloro-5-fluoro-2-trifluoromethylbenzimidazol-4-yl)-l-methyl-6- trifluoromethyl-2,4(lH,3H)pryimidinedione and a 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound may be formulated into a more concentrated primary composition which is diluted with water or other diluent before use. Such compositions may comprise a surface active agent in addition to the active ingredients and examples of such compositions are set forth below.

The herbicidal compounds of the present invention may be formulated as a granule of relatively large particle size (for example, 8/16 or 4/8 US Mesh), as water- soluble or water-dispersible granules, as powdery dusts, as wettable powders, as emulsifiable concentrates, as aqueous emulsions, as solutions, or as any of the other known types of agriculturally -useful formulations, depending on the desired mode of application to the areas in which suppression of vegetation is desired. These formulations may contain as little as 0.1%, 0.2% or 0.5% to as much as 95% or more by weight of the total of the two herbicides.

The composition can be in the form of a dispersible solution which comprises the herbicides dissolved in a water-miscible solvent with the addition of a dispersing agent. Alternatively it can comprise the herbicides in the form of a finely ground powder in association with a dispersing agent and intimately mixed with water to give a paste or cream which can if desired be added to an emulsion of oil in water to give a dispersion of the two herbicides in an aqueous oil emulsion. Alternatively, the composition can be in the form of water-soluble or water- dispersible granules that disperse readily in water or other dispersant. Water-soluble or water-dispersible granules (WG) normally are prepared to contain about 5-80% of the herbicides, depending on the absorbency of the carrier, and usually also contain a wetting, dispersing or emulsifying agent to facilitate dispersion and may contain a preservative. Typical carriers for water-soluble or water-dispersible granules include Fuller's earth, natural clays, silicas, and other highly absorbent, readily wet inorganic diluents. For example, a useful water-soluble or water-dispersible granule formulation contains 26.71 parts of the herbicidal compounds, 30.90 parts of ammonium sulfate, 30.89 parts of continental clay, 10.00 parts of sodium lignosulfonate as a dispersant, 1.00 part of sodium dioctylsuccinate as a wetting agent and 0.50 part of citric acid as a preservative. The mixture is milled, diluted with water to form a paste and the paste is extruded and dried to produce granules.

Other alternatives that may be employed are dusts which are free flowing admixtures of the herbicides with finely divided solids such as talc, natural clays, kieselguhr, flours such as walnut shell and cottonseed flours, and other organic and inorganic solids which act as dispersants and carriers for the herbicides. These finely divided solids have an average particle size of less than about 50 microns. A typical dust formulation useful herein is one containing 1.0 part or less of the herbicidal compounds and 99.0 parts of talc. Also useful formulations for the herbicidal compositions of the present invention are wettable powders in the form of finely divided particles that disperse readily in water or other dispersant. The wettable powder is ultimately applied to the locus where weed control is needed either as a dry dust or as an emulsion in water or other liquid. Typical carriers for wettable powders include Fuller's earth, kaolin clays, silicas, and other highly absorbent, readily wet inorganic diluents. Wettable powders are prepared to contain about 5-80% of the herbicides, depending on the absorbency of the carrier, and usually also contain a small amount of a wetting, dispersing or emulsifying agent to facilitate dispersion. For example, a useful wettable powder formulation contains 80.0 parts of the herbicidal compounds, 17.9 parts of Palmetto clay, and 1.0 part of sodium lignosulfonate and 0.3 part of sulfonated aliphatic polyester as wetting agents. Additional wetting agents and/or oils will frequently be added to a tank mix to facilitate dispersion on the foliage of the plant. Other useful formulations for the herbicidal compositions of the present invention are emulsifiable concentrates (ECs) which are homogeneous liquid compositions dispersible in water or other dispersant, and may consist entirely of the herbicidal compounds and a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthas, isophorone, or other non- volatile organic solvents. For herbicidal application these concentrates are dispersed in water or other liquid carriers and applied as a spray to the area to be treated. The percentage by weight of the herbicidal compounds may vary according to the manner in which the composition is to be applied, but in general comprises 0.5 to 95% of the herbicidal compounds by weight of the total composition. Suspension concentrate formulations (SCs) may also be employed. These are similar to ECs, except that the herbicidal compounds are suspended in a liquid carrier, generally water, suspension concentrates, like ECs, may include small amounts of surfactants, emulsifiers, stabilizers, thickeners, antifoam agents and/or preservatives and will typically contain the herbicidal compounds in the range of 0.5 to 95%, frequently from 10 to 50%, by weight of the total composition. For herbicidal application, flowables may be diluted in water or other liquid vehicle, and are normally applied as a spray to the area to be treated.

Other useful formulations include suspensions of the herbicidal compounds in a relatively non-volatile solvent such as water, corn oil, kerosene, propylene glycol, or other suitable solvents.

Still other useful formulations for these herbicidal compositions include simple solutions of the herbicides in a solvent in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene, or other organic solvents. Granular formulations, wherein the herbicides are carried on relative coarse particles, are of particular utility for aerial distribution or for penetration of cover crop canopy. Pressurized sprays, typically aerosols wherein the herbicides are dispersed in finely divided form as a result of vaporization of a low- boiling dispersant solvent carrier may also be used. Another useful formulation for the herbicidal compositions of the present invention is micro encapsulation. This method of formulation is a process in which either one or both of the herbicidal compounds may be encapsulated in a shell of polyurea, polyamide or amide-urea copolymer as disclosed in EP 0792100 Bl and U. S. Patent 5,583,090.

In some circumstances it may be desirable to combine two types of formulation e.g. one of the herbicidal compounds is used as an emulsifiable concentrate and the second herbicidal compound is dispersed as a powder in this concentrate. The concentrate of the first and second herbicides (when used as the sole active components) in a composition for direct application to the crop by conventional ground methods is preferably within the range of 0.001 to 10 % by weight of the composition, especially 0.005 to 5 % by weight, but more concentrated compositions containing up to 40 % may be desirable. Typical wetting, dispersing or emulsifying agents that may be used in the compositions of the present invention include, but are not limited to, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; alkylaryl polyether alcohols; sulfated higher alcohols; polyethylene oxides; sulfonated animal and vegetable oils; sulfonated petroleum oils; fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such esters; and the addition product of long-chain mercaptans and ethylene oxide. Many other types of useful surface-active agents are available in commerce. Surface-active agents, when used, normally comprise 1 to 15% by weight of the composition.

In use on the field, the granular formulations, emulsifiable concentrates, flowable concentrates, aqueous emulsions, solutions, etc., may be diluted with water to give a concentration of the active ingredient in the range of 0.01% or 0.2% to 1.5% or 2.0%.

The invention is illustrated in the following Examples which describe experiments in which a beneficial effect was observed. The desired concentration of the active ingredients was achieved by diluting, with water, the commercially available herbicide formulation of mesotrione (Callisto® Herbicide, Syngenta Crop Protection, Inc.), isoxaflutole (Balance Pro® Herbicide, Bayer CropScienceLP), sulcotrione (Mikado® Herbicide, Bayer CropScienceLP) and a 2 pound per gallon suspension concentrate formulation (2 SC) or a 25% by weight water soluble granule formulation (25 WG) of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)-l- methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione, each of which contained conventional surfactants, emulsifiers, stabilizers, thickeners, antifoam and/or preservatives. EXAMPLE 1

Post-emergent herbicidal evaluation of 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl-

2,4(lH,3H)pyrimidinedione, 4-HPPD inhibitor compounds and mixtures thereof

The compositions of the present invention were tested for herbicidal efficacy in the following manner:

Test compositions of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7- yl)-l-methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione (2SC or 25 WG) were prepared in a spray tank that provided the appropriate pound per acre application rate of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)-l-methyl-6- trifluoromethyl-2,4(lH,3H)pyrimidinedione. Test compositions of 4-HPPD inhibitor compounds were prepared in a spray tank that provided the appropriate pound per acre application rate. A crop oil concentrate or a non-ionic surfactant spray additive was added to these test compositions. Test compositions of mixtures of 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione (2 SC or 25 WG) and a 4-HPPD inhibitor compound were prepared in a tank mix that provided appropriate rates of application of combinations of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl- 6-trifluoromethyl-2,4(lH,3H)pyrimidinedione and the 4-HPPD inhibitor compound. A crop oil concentrate or a non-ionic spray additive was added to these test compositions.

The application of the test rate was performed with pressurized back-pack sprayers, calibrated to spray 20 gallons per acre (Table 1) or 250 liters per hectare (Table IA).

The experimental design used randomized plots with one post-emergent treatment and four replications per test trial. An untreated check plot was included for each trial to compare to the treated plots for percent control purposes. The size of each experimental plot was 7 feet by 20 feet (Table 1) or 2.5 meters by 8 meters (Table IA). The appearance of the crop and the population of the weeds were assessed and averaged at 15 to 32 days after application (DAA) of each test rate, the results are in Tables 1 and IA below. The test weeds include common lambsquarters {Chenopodium album), ivyleaf morningglory (Ipomoea hederacea), pitted morningglory (Ipomeoa lacunosά), black nightshade {Solarium nigrum), common ragweed {Ambrosia artemisifolia), giant ragweed {Ambrosia triflda), common cocklebur {Xanthium strumarium), common sunflower {Helianthus annuus), velvetleaf {Abutilon theophrasti), common water hemp {Amaranthus rudis) tall waterhemp {Amaranthus tuberculatus) , marestail {Hippuris vulgaris), redroot pigweed {Amaranthus retroflexus), palmer amaranth {Amaranthus palmeri), hedge bindweed {Calystegia sepium) and pale smartweed {Polygonum lapathifolium).

TABLE 1

Post-emergence Herbicidal Activity of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione (Cmpd A), Mesotrione (Cmpd B) and Mixtures Thereof

Highlighted numbers indicate advantageous herbicidal properties.

* A -marestail, B -common ragweed, C - giant ragweed, D - redroot pigweed, E - tall waterhemp, F - common waterhemp, G - palmer amaranth, H - ivyleaf morningglory, I - pitted morningglory, J - hedge bindweed, K - common sunflower, L - velvetleaf, M - common cocklebur, N - common lambsquarters. ** Label use rate for Callisto® Herbicide

1 - One trial

2 - Two trials

3 - Three trials

TABLE IA

Post-emergence Herbicidal Activity of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(1 H,3H)pyrimidinedione (Cmpd A), Sulcotrione (Cmpd C) and Mixtures Thereof

Highlighted numbers indicate advantageous herbicidal properties.

* D redroot pigweed, N - common lambsquarters, O - black nightshade, P - pale smartweed.

EXAMPLE 2

Pre-emergent herbicidal evaluation of 3-(4-chloro-6-fluoro-2- trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl-

2,4(lH,3H)pyrimidinedione, 4-HPPD inhibitor compounds and mixtures thereof

Test compositions of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 - methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione (2 SC) and acetochlor (2-chloro-N- (ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide, Harness® Herbicide, Monsanto Company, an herbicide that is not a 4-HPPD inhibitor compound) were prepared in a spray tank that provided the appropriate pound per acre application rate of 3-(4-chloro-6- fluoro-2-trifluoromethylbenzimidazol-7-yl)-l-methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione and acetochlor. Test compositions of 4-HPPD inhibitor compounds were prepared in a spray tank that provided the appropriate pound per acre application rate.

Test compositions of mixtures of 3-(4-chloro-6-fluoro-2- trifluoromethy lbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl-

2,4(lH,3H)pyrimidinedione (2 SC), acetochlor and a 4-HPPD inhibitor compound were prepared in a tank mix that provided appropriate rates of application of combinations of 3 -(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione and the 4-HPPD inhibitor compound. A crop oil concentrate was added to these test compositions.

The application of the test rate was performed with pressurized back-pack sprayers, calibrated to spray 20 gallons per acre.

The experimental design used randomized plots with one pre-emergent treatment and four replications per test trial. An untreated check plot was included for each trial to compare to the treated plots for percent control purposes. The size of each experimental plot was 7 feet by 20 feet.

The appearance of the crop and the population of the weeds were assessed and averaged at 60 days after application (DAA) of each test rate, the results are in Table 2 below. The test weeds include ivyleaf morningglory (Ipomoea hederacea), common ragweed (Ambrosia artemisifoliά), giant ragweed (Ambrosia trifida), common sunflower (Helianthus annuus), velvetleaf (Abutilon theophrasti), palmer amaranth (Amaranthus palmeri), hedge bindweed (Calystegia sepium), prickly sida (Sida spinosa), barnyard grass (Echinochloa crus-galli), buffalobur (Solarium rostratum), Canada thistle (Cirsium arvense), yellow foxtail (Setaria lutescens), giant foxtail (Setaria faverii), green foxtail (Setaria viridis), Pennsylvania smartweed (Polygonum pennsylvanicum) and large crabgrass (Digitaria ischmaemum).

TABLE 2

Pre-emergence Herbicidal Activity of 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione (Cmpd A) and Acetochlor, Mesotrione (Cmpd B), Isoxaflutole (Cmpd D) and Mixtures Thereof

Highlighted numbers indicate advantageous herbicidal properties.

* B -common ragweed, C - giant ragweed, D - redroot pigweed, E - tall waterhemp, G - palmer amaranth, H - ivyleaf morningglory, J - hedge bindweed, K common sunflower, L - velvetleaf, N - common lambsquarters, Q - prickly sida, R - barnyard grass, S - bufflaobur, T - Canada thistle, U - yellow foxtail, V - giant foxtail, W - green foxtail, X - large crabgrass, Y - Pennsylvania smartweed.

1 - Two trials

2 - Three trials

3 - Five trials

Those of ordinary skill in the art will appreciate that variations of the invention may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the following claims.

Claims

What is claimed is:

1 An herbicidal composition comprising a first herbicide and a second herbicide in which the first herbicide is 3-(4-chloro-6-fluoro-2-trifluoromethylbenzimidazol-7-yl)-l- methyl-6-trifluoromethyl-2,4(lH,3H)pyrimidinedione and the second herbicide is a 4- hydroxyphenyl-pyruvate-dioxygenase (4-HPPD) inhibitor compound.

2 The composition according to claim 1 wherein the ratio of 3-(4-chloro-6-fluoro-2- trifluoromethy lbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione to the 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound is from 1 :0.1 to 1 :40.

3 The composition according to claim 2, wherein the ratio of 3-(4-chloro-6-fluoro- 2-trifluoromethylbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione to the 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound is from 1 :0.3 to 1 :10.

4 The composition according to claim 1 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole, sulcotrione, topramezone, tembotrione, benzofenap, pyrazolynate, pyrazoxyfen, pyrasulfotole and tefuryltrione.

5 The composition according to claim 4 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole and sulcotrione.

6 A method for controlling weeds comprising applying a composition of claim 1 to a locus where weeds are present or are expected to be present.

7 A method according to claim 6 wherein the ratio of 3-(4-chloro-6-fluoro-2- trifluoromethy lbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione to the 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound is from 1 :0.1 to 1 :40.

8 A method according to claim 7 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole, sulcotrione, topramezone, tembotrione, benzofenap, pyrazolynate, pyrazoxyfen, pyrasulfotole and tefuryltrione.

9 A method according to claim 8 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole and sulcotrione.

10 A method according to claim 7 wherein the ratio of 3-(4-chloro-6-fluoro-2- trifluoromethy lbenzimidazol-7-yl)- 1 -methyl-6-trifluoromethyl- 2,4(lH,3H)pyrimidinedione to the 4-hydroxyphenyl-pyruvate-dioxygenase inhibitor compound is from 1 :0.3 to 1 :10.

11 A method according to claim 10 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole, sulcotrione, topramezone, tembotrione, benzofenap, pyrazolynate, pyrazoxyfen, pyrasulfotole and tefuryltrione.

12 A method according to claim 11 wherein the 4-hydroxyphenyl-pyruvate- dioxygenase inhibitor compound is an herbicide selected from the group consisting of mesotrione, isoxaflutole and sulcotrione.