NZ588247A - Synergistic Herbicidal Compositions comprising diflufenican and flumetsulam - Google Patents

Abstract

Disclosed is a selective, synergistic herbicidal composition comprising as active ingredients: (A) diflufenican and (B) flumetsulam, characterised in that active ingredients (A) and (B) are present in synergistically effective ratios from about 20:1 to about 1:20 by weight. Also disclosed is a method for the selective control or suppression of weeds which comprises applying to plants, parts of plants, plant seeds or to soil a herbicidally effective amount of the synergistic composition accordingly to any of the preceding claims characterised in that active ingredients (A) diflufenican and (B) flumetsulam are present in synergistically effective ratios from about 20:1 to about 1 :20 by weight and whereby the composition is applied at a rate ranging from about 50 gai/ha to about 1,500 gai/ha based on the combined weights of (A) diflufenican and (8) flumetsulam. Diflufenican is 2',4'-difluoro-2-(a,a,a-trifluoro-m-tolyloxy) nicotinanilide. Flumetsulam is 2',6'-difluoro-5-methyl[1 ,2,4]triazolo[1 ,5-a]pyrimidine-2-sulfonanilide.

Description

New Zealand Paient Spedficaiion for Paient Number 588247 NEW ZEALAND Patents Act 1953 COMPLETE AFTER PROVISIONAL SPECIFICATION. NZ 5288247 SYNERGISTIC HERBICIDAL COMPOSITIONS We, ZELAM LTD, Hudson Road, New Plymouth 4341, New Zealand, do hereby declare this invention to be described in the following statement:- BACKGROUND This invention relates to a herbicidal composition and more particularly, but not exclusively it relates to a synergistic, selective herbicidal composition, to its method of preparation, and to its method of use.

Herbicides are used in different ways in agriculture ranging from total knockdown of existing herbage prior to cultivation and/or resowing, to the application of selective herbicides to established crops to kill established weeds. An intermediate situation exists in the early stages of cereal, seed and fodder cropping and pasture establishment where herbicides are applied pre or post seedling emergence to kill weeds, or halt, stall or retard weed growth in order to eliminate or minimise competition and thus maximise growth and production of a desired crop species.

In this situation the crop may be more herbicide-sensitive. Some weed control objectives, such as control of broadleaf and grass species in a clover seed crop are very demanding, and highly selective herbicidal active ingredients must be used. Nevertheless, severe stunting of crop plants may still occur at herbicide application rates high enough for satisfactory weed control. For example, bleaching herbicidal active ingredients such as the phytoene desaturase inhibitor diflufenican, which can be used for control of broadleaf species in new pasture containing clover or in a clover seed crop, typically causes characteristic bleaching of newly emergent crop foliage with corresponding stunting of new growth.

Deleterious crop effects may restrict the use of a herbicide to certain crop development stages, e.g. during clover establishment diflufenican should only be used at the four trifoliate stage and beyond, at which point weed control is more difficult than at earlier stages.

Still further problems exist in that high application rates may present residue problems resulting in unacceptably long withholding periods prior to grazing or harvesting of the crop.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. The applicant makes no admission that any reference constitutes prior art - they are merely assertions by their authors and the applicant reserves the right to contest the accuracy, pertinence and domain of the cited documents. None of the documents or references constitutes an admission that they form part of the common general knowledge in NZ or in any other country 2 SUMMARY It is an object of the invention to provide an improved composition and/or preparative method thereof and/or use thereof which will obviate or minimize one or more of the previously mentioned disadvantages, or which will at least provide the public with a useful choice.

Surprisingly, we have found that herbicidal compositions comprising as active ingredients a combination of : (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, are synergistic at certain ratios of (A) to (B), The effective dose required can be lowered as a result of the synergy making the resulting products and crop production systems more economical, and minimising or eliminating one or more of the previously mentioned problems.

In one broad aspect this invention provides synergistic, selective herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof.

In a further broad aspect this invention provides synergistic, selective herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, and further comprising a third herbicidal active ingredient (C) consisting of an auxin herbicide.

In a further broad aspect this invention provides methods of formulating synergistic herbicidal compositions of the invention.

In a further broad aspect this invention provides a method of selectively controlling weeds, which comprises applying to plants, parts of plants, plant seeds, or to soil, synergistic , herbicidally effective amounts of compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof. 3 In a further surprising aspect we have found that synergistic, selective herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, and further comprising a third herbicidal active ingredient (C) comprising of one or more auxin herbicides, broaden the spectrum of weed control and increase the desired herbicidal activity against partially controlled weeds or certain difficult-to-control weeds, or difficult-to-control weed growth stages.

A synergistic herbicidal composition comprising as active ingredients: (A) diflufenican and (B) flumetsulam, when used to selectively control or suppress plant growth, the composition being characterised in that active ingredients (A) and (B) are present in synergistically effective ratios from about 20:1 to about 1:20 by weight and whereby the composition is applied at a rate ranging from about 50 gai/ha to about 1,500 gai/ha based on the combined weights of diflufenican and flumetsulam.

Accordingly, in a still further broad aspect this invention provides compositions comprising synergistic, selective herbicidal compositions comprising active ingredients (A) and (B) and, optionally, further comprising a third herbicidal active ingredient (C) consisting of one or more auxin herbicides, and methods of use thereof.

DETAILED DESCRIPTION This invention relates generally to combinations of herbicidal active ingredients and more particularly to synergistic combinations of herbicidal active ingredients intended to provide more effective and broader control of weed species and/or increase crop safety and/or reduce herbicide residues.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The term "herbicidal" encompasses all plant growth controlling or modifying effects including, but not limited, to killing, halting, stalling, retarding, stunting, dwarfing, leaf burn, albinism, suppression, distortion, twisting, abnormal irregular growth, inhibition of growth, inhibition of germination, disruption of flowering, and the like. 4 Moreover the term "herbicidal" includes partial, intermediary, transitional or reversible effects including, but not limited to, discolouration, yellowing, browning, whitening, bleaching, chlorosis, various other phytotoxic effects, and the like.

The term "herbicidally effective amount" indicates the quantity or application rate of a herbicidal composition which is capable of producing any one or more such plant growth controlling or modifying effects. The terms "plant" or "plants" refer to whole plants and/or plant parts including, but not limited to, seeds and other propagules, seedlings, roots, tubers, corms, offsets, runners, stems, stalks, buds, foliage, flowers and fruits.

A "selective" herbicide is one which is sprayed over a crop to kill weeds without injury to the crop. A selective herbicide discriminates between target and non-target plants.

A "non-selective herbicide" is used to kill all plants (crops plus weeds) in a desired target zone. In other words a non-selective herbicide doesn't discriminate between target and non-target plants.

"Contact herbicides" destroy only the plant tissue in contact with the chemical. Generally, these are the fastest acting herbicides. They are less effective on perennial plants, which are able to regrow from rhizomes, roots or tubers.

"Systemic herbicides" are translocated through the plant, either from foliar application down to the roots, or from soil application up to the leaves. They are capable of controlling perennial plants and may be slower acting but ultimately more effective than contact herbicides "Control" is the destruction of unwanted weeds, or the damage of them to the point where they are no longer competitive with the crop.

"Suppression" is incomplete control still providing some economic benefit, such as reduced competition with the crop.

"Crop Safety", for selective herbicides, is the relative absence of damage or stress to the crop. Most selective herbicides cause some visible stress to crop plants.

The term "synergistic" refers to a particular effect and may be calculated as defined by R. S. Colby ("Calculating Synergistic and Antagonistic Responses of Herbicide Combinations", 1967, Weeds 15, 20-22). Colby's publication discloses the formula: E = X + Y - (XY)/100, in which, X represents the percent inhibition of growth by herbicide A at x grams of active ingredient per hectare (gai/ha), Y represents the percent inhibition of growth by herbicide B at y gai/ha, and E represents the expected percent inhibition of growth by herbicides A + B in combination at x + y gai/ha, respectively.

When the observed percent inhibition of growth by herbicides A + B is greater than E (expected), the combination is synergistic. If the observed inhibition is less than expected, the combination is antagonistic, and when observed and expected inhibitions are equal, the combination is additive. Colby also presents alternative methods of calculation for original data expressed as percent-of-control values and for three-way synergistic interactions.

Surprisingly, we have found that herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, characterised that components (A) and (B) are present in ratios producing a synergistic herbicidal effect yield enhanced herbicidal activity against a range of weeds, i.e., the inhibitory effects on weed growth by the combinations of active ingredients is unexpectedly greater than the expected effects calculated using the Colby formula based on the effects of individual active ingredients. The effective application rates required can be lowered as a result of this synergy making the resulting products and crop production systems more economical, and minimising or eliminating one or more of the previously mentioned problems.

If the active compounds in the synergistic composition according to the invention are present in certain weight ratios, the synergistic effect is particularly pronounced. However, the weight ratios of the active compounds in the synergistic composition can be varied within a relatively wide range.

The ratios of active ingredients (A) to (B) indicated in this disclosure do not in any way limit the scope of this invention, but are rather mentioned as a guide, a person of ordinary skill in the art being entirely capable of carrying out complementary experiments in order to find other values of the ratios of active ingredients which produce a synergistic effect.

The disclosed herbicidal composition may comprise as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide and (B) at least one triazolopyrimidine herbicide and/or salts thereof, the active ingredients (A) and (B) being in ratios producing a synergistic herbicidal effect.

Examples of suitable phytoene desaturase-inhibiting herbicides may include, but are not limited to: 6 diflufenican (2',4'-difluoro-2-(a,a,a-trifluoro-/77-tolyloxy) nicotinamide), picolinafen (4'-fluoro-6-(a,a,a-trifluoro-m-tolyloxy)pyridine-2-carboxanilide), norflurazon (4-chloro-5-methylamino-2-(a,a,a-trifluoro-m-tolyl)pyridazin-3(2/-/)-one), beflubutamid (A/-benzyl-2-(a,a,a,4-tetrafluoro-m-tolyloxy)butyramide), fluridone (1-methyl-3-phenyl-5-(a,a,a-trifluoro-m-tolyl)-4-pyridone), flurochloridone ((3RS,4f?S;3RS,4SR)-3-chloro-4-chloromethyl-1-(a,a,a-trifluoro-m-tolyl)-2-pyrrolidone (isomers in the ratio 3:1), flurtamone ((RS)-5-methylamino-2-phenyl-4-(a,a,a-trifluoro-m-tolyl)furan-3(2/-/)-one), and MT 141 (4-ethyl-3-(3-fluorophenyl)-1-(3-trifluoromethylphenyl)pyrrolidin-2-one).

Preferably active ingredient (A) is one or more phytoene desaturase-inhibiting herbicides selected from the group consisting of diflufenican, picolinafen, norflurazon, beflubutamid, fluridone, flurochloridone, flurtamone and MT 141.

More preferably active ingredient (A) is selected from the group consisting of diflufenican, picolinafen, norflurazon, beflubutamid and fluridone.

Still more preferably active ingredient (A) is selected from the group consisting of diflufenican, picolinafen, norflurazon and beflubutamid.

Examples of suitable triazolopyrimidine herbicides, may include, but are not limited to: cloransulam (3-chloro-2-(5-ethoxy-7-fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-ylsulfonamido)benzoic acid), cloransulam-methyl (methyl 3-chloro-2-(5-ethoxy-7-fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-ylsulfonamido)benzoic acid, diclosulam (/V-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide), florasulam (2',6',8-trifluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonanilide), flumetsulam (2',6'-difluoro-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide), metosulam (2',6'-dichloro-5,7-dimethoxy-3'-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide), penoxsulam (3-(2,2-difluoroethoxy)-A/-(5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)-a,a,a-trifluorotoluene-2-sulfonamide), pyroxsulam (A/-(5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidin-2-yl)-2-methoxy-4-(trifluoromethyl)pyridine-3-sulfonamide), and salts thereof. 7 Preferably active ingredient (B) is one or more triazolopyrimidine herbicides selected from the group consisting of cloransulam, cloransulam-methyl, diclosulam, florasulam, flumetsulam, metosulam, penoxsulam, and pyroxsulam, and/or salts thereof.

More preferably active ingredient (B) is selected from the group consisting of florasulam, flumetsulam, metosulam, pyroxsulam, and/or salts thereof.

The invention includes all herbicidally active forms of triazolopyrimidine herbicides including acids, esters, salts and partial salts. For example cloransulam contains an esterifiable carboxylic acid moiety which may be reacted with a range of alcohols to produce other esters in addition to cloransulam-methyl. The triazolopyrimidine herbicides can also form salts by virtue of the acidic proton on the NH group in the sulphonamide bridge. Thus in addition to the use of neutral triazolopyrimidine herbicides, these compounds may be used as salts together with agriculturally suitable inorganic and/or inorganic counterions. Examples of suitable counterions may include but are not limited to alkali metal ions, alkaline earth metal ions, ammonium ions, quaternary ammonium ions, organic amines, the conjugate bases of organic and inorganic acids.

The disclosed herbicidal composition may further comprise a third herbicidal active ingredient (C) comprising of one or more auxin herbicides, in order to broaden the spectrum of herbicidal activity.

Examples of suitable auxin herbicides may include, but are not limited to: 2,4-D ((2,4-dichlorophenoxy)acetic acid), 2,4-DB (4-(2,4-dichlorophenoxy)butyric acid), 4-CPA (4-chlorophenoxyacetic acid), aminopyralid (4-amino-3,6-dichloropyridine-2-carboxylic acid) benazolin (4-chloro-2,3-dihydro-2-oxo-1,3-benzothiazol-3-ylacetic acid), clomeprop ((RS)-2-(2,4-dichloro-/77-tolyloxy)propionanilide), clopyralid (3,6-dichloropyridine-2-carboxylic acid), dicamba (3,6-dichloro-2~methoxybenzoic acid), dichlorprop ((RS)-2-(2,4-dichlorophenoxy)propionic acid), dichlorprop-P ((R)-2-(2,4-dichlorophenoxy)propionic acid), fluroxypyr (4-amino-3,5-dichloro-6-fluoro-2-pyridyloxyacetic acid), MCPA (4-chloro-o-tolyloxyacetic acid), 8 MCPA thioethyl (S-ethyl 4-chloro-o-tolyloxythioacetate), MCPB (4-(4-chloro-o-tolyloxy)butyric acid), mecoprop ((RS)-2-(4-chloro-o-tolyloxy)propionic acid), mecoprop-P ((R)-2-(4-chloro-o-toIyloxy)propionic acid), picioram (4-amino-3,5,6-trichioropyridine-2-carboxyiic acid), quinclorac (3,7-dichloroquinoIine-8-carboxylic acid), quinmerac (7-chloro-3-methylquinoline-8-carboxylic acid), triciopyr (3,5,6-trichloro-2-pyridyioxyacetic acid), and esters and salts thereof.

Preferably active ingredient (C) is one or more auxin herbicides selected from the group consisting of 2,4-D, 2,4-DB, 4-CPA, aminopyralid, benazolin, clomeprop, clopyralid, dicamba, dichlorprop, dichlorprop-P, fluroxypyr, MCPA, MCPA thioethyl, MCPB, mecoprop, mecoprop-P, picioram, quinclorac, quinmerac, triciopyr, and esters and salts thereof.

More preferably active ingredient (C) is selected from the group consisting of 2,4-D, 2,4-DB, 4-CPA, aminopyralid, benazolin, clopyralid, dicamba, dichlorprop, dichlorprop-P, fluroxypyr, MCPA, MCPA thioethyl, MCPB, mecoprop, mecoprop-P, picioram, quinclorac, triciopyr, and esters and salts thereof, any of which can be used where damage to sensitive crops such as clover is not of concern.

In compositions where clover damage must be minimised, active ingredient (C) is preferably selected from the group consisting of 2,4-D, 2,4-DB, 4-CPA, benazolin, MCPA, MCPB, quinclorac, and esters and salts thereof.

Still more preferably for clover containing crops, active ingredient (C) is selected from 2,4-DB, 4-CPA and MCPB.

The invention includes all herbicidally active forms of auxin herbicides including esters, salts, and partial salts. Almost all contain an esterifiable carboxylic acid moieties able to react with a range of alcohols, or form salts or partial salts. Examples of suitable counterions may include but are not limited to alkali metal ions, alkaline earth metal ions, ammonium ions, quaternary ammonium ions, organic amines, the conjugate bases of organic and inorganic acids. 9 The chosen forms of active ingredient (B) and/or (C), i.e. acid, ester, salt, or partial salt, may be based on solubility in different solvents and the type of formulation desired, for example, and taking into account other properties such as active ingredient volatility and consequent effects on herbicidal activity or unwanted crop effects.

According to the invention, synergistic combinations of active ingredients (A) and (B) may be found when the relative amounts of ingredients (A) and (B) are present within the range, expressed as a ratio (A): (B), from about 1 : 0.001 to about 1 : 1,000 parts by weight.

Suitably active ingredients (A) and (B) are present in a ratio (A): (B) from about 100 :1 to about 1 ; 100 parts by weight. More suitably active ingredients (A) and (B) are present in a ratio (A): (B) from about 50 :1 to about 1 : 50 parts by weight. Still more suitably active ingredients (A) and (B) are present in a ratio (A): (B) from about 20 :1 to about 1 : 20 parts by weight. Still more suitably active ingredients (A) and (B) are present in a ratio from about 10 :1 to about 1:10 parts by weight. Still more suitably active ingredients (A) and (B) are present in a ratio from about 5:1: to about 1 : 5 parts by weight.

The composition may comprise 0.1% to 80% active ingredient (A) and 0.1% to 80% active ingredient (B) on a weight/weight basis or a weight/volume basis. Optionally, in addition to active ingredients (A) and (B), the composition may further comprise 0.1 % to 90% of auxin herbicide (C) on a weight/weight basis or a weight/volume basis. The percentages of active ingredients in the composition will depend mainly on the formulation type and intended method of application.

Suitable formulation types and methods are described, for example, in "Chemistry and Technology of Agrochemical Formulations", 1998, D. A. Knowles (editor), Kluwer Academic Publishers, "Pesticide Formulation and Adjuvant Technology", 1966, C. L. Foy (editor), CRC Press, and "Formulation Technology: Emulsions, Suspensions, Solid Forms", 2001, H. Mollet and A. Grubenmann, Wiley-VCH. Suitable formulation types for the herbicidal composition include, but are not limited to, a granule, a powder, a concentrate, a gel, a liquid, an oil dispersion, a suspension, or a controlled release form including a microcapsule. More suitable formulation types are a concentrate, an emulsion, a suspension, a suspo-emulsion, an oil dispersible suspension, a water dispersible granule, or a solution.

In addition to active ingredients (A) and (B), and optionally (C), the herbicidal composition may contain 0.1% to 99% of customary formulation additives. Customary formulation additives and their functions are described in the previously mentioned publications. Such additives may include water, agriculturally suitable surfactants, dispersants, emulsifiers, penetrants, spreaders, wetting agents, soaps, carriers, oils, solvents, diluents, inert ingredients, conditioning agents, colloids, suspending agents, thickeners, thixotropic agents, polymers, emollients, acids, bases, salts, organic and inorganic solid matrices of various kinds, preservatives, anti-foam agents, anti-freeze agents, anti-caking agents, lubricants, stickers, binders, glues, resins, complexing agents, chelating agents, crystallization inhibitors, dyes, activators, synergists, safeners, UV protectants, fertilizers, micronutrients, and the like.

Compositions are formulated using known methods by dissolving, dispersing, finely dividing, slurrying, emulsifying, homogenizing, stirring, high-shear mixing, comminuting, milling, stabilising, etc, the active ingredients, and by admixing with appropriate quantities of the one or more previously mentioned customary formulation additives to form the composition of the invention. Further details of suitable methods of manufacture of the composition are provided in the examples.

The invention provides a method of selectively controlling weeds, which comprises applying to plants, parts of plants, plant seeds or to soil, herbicidally effective amounts of synergistic herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof.

The invention also provides a method of selectively controlling weeds, which comprises applying to plants, parts of plants, plant seeds or to soil, herbicidally effective amounts of synergistic herbicidal compositions comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, the composition optionally further comprising an auxin herbicide (C).

The composition may be applied at any stage of the crop cycle. The composition may be applied to soil before planting of the crop seed, or applied to soil at the same time as seed is applied, for example during drilling. The composition may be applied after planting of the crop seed but before emergence of the crop, i.e. pre-emergence application, or after planting and emergence of the crop, i.e. post-emergence application. The composition may also be applied before or after transplantation of seedlings. The preferred mode of use is as a pre-emergence or post-emergence herbicide.

In general the composition may be diluted into a carrier and applied by conventional means to soil, plants and parts thereof. Water is the carrier of choice and the formulation may be mixed into water and applied by spraying, sprinkling or wicking, or added to irrigation water. Dry compositions such as powders and granules, and liquid formulations may be applied directly to soil and/or dispersed below the surface by conventional cultivation techniques.

Other biocidal active ingredients may be combined with the herbicidal composition of the invention, and may include other herbicides, fungicides, bactericides, insecticides, nematicides, and the like. These active 11 ingredients may be added as a "tank mixture". In addition other additives such as plant growth regulators and fertilizers may be combined with the composition or dilutions thereof.

Active ingredients (A) and (B), and where applicable (C), of the composition may be applied sequentially or, preferably, simultaneously. The active ingredients together with other additives are advantageously pre-formulated as a single mixture but may also be formulated separately and "tank mixed" prior to application. Various combinations of separately formulated active ingredients and other customary formulation additives, and the mixing thereof, can be envisaged in the tank mixing scenario. A common occurrence may be the addition of one or more surfactants during tank mixing. Active ingredients (A) and (B) may be applied sequentially, in any order and in any timescale, suitably within a one week period, more suitably within a 24 hour period, and, preferably, within one hour.

The use rate for the composition is dependent on the timing and method of application, the range of weed species to be controlled, the degree of control required, as well as the herbicide tolerance of the crop.

The composition can be applied at a rate ranging from about 1 gram active ingredient per hectare (gai/ha) to about 4,500 gai/ha, based on the combined rate of active ingredients (A) and (B).

Suitable use rates for active ingredient (A) range from about 1 gai/ha to about 3,000 gai/ha. More suitably the use rate for active ingredient (A) ranges from about 20 gai/ha to about 2,000 gai/ha. Still more suitable the use rate for active ingredient (A) ranges from about 50 gai/ha to about 1,000 gai/ha.

Suitable use rates for active ingredient (B) range from about 1 gai/ha to about 1,500 gai/ha. More suitably the use rate for active ingredient (B) ranges from about 20 gai/ha to about 1,000 gai/ha. Still more suitable the use rate for active ingredient (B) ranges from about 50 gai/ha to about 500 gai/ha Suitable use rates for the optional auxin herbicide (C) are from about 1 gai/ha to about 3,000 gai/ha. More suitably the use rate for active ingredient (C) ranges from about 20 gai/ha to about 2,500 gai/ha. Still more suitable the use rate for active ingredient (C) ranges from about 50 gai/ha to about 2,000 gai/ha.

A person of ordinary skill in the art will acknowledge the value of product label claims and directions for use in determining suitable applications and use rates for the compositions of this invention.

The invention is applicable to any cropping situation including knockdown of existing herbage prior to cultivation and resowing, and control of established weeds within established crops and trees. 12 The invention is suitable for weed control at any stage in the establishment and maintenance of cereal crops, seed crops, fodder crops and pasture. The invention is more suitable for weed control during the early stages of cereal, seed and fodder cropping and pasture establishment where the composition may be applied at anytime during soil preparation, sowing, transplantation, seedling emergence and crop growth.

The invention is particularly suitably for use pre or post seedling emergence to control weeds and maximise growth and production of desired cereal crops, seed and fodder crops and pasture. The invention is suited to cereal, grass and legume species including species grown for forage and fodder including fresh, fermented and dried fodder. The invention is especially suited for the production of seed for use in pasture, turf and vegetable production where it is critical to obtain seed uncontaminated with weed seeds.

The invention may be used in a wide range of forage, cropping, orchard and forestry operations including fallow periods with suitable crops including, but not limited to, turf, pastures and fodder crops, cereal, grain and seed crops, vegetables including fodder and vegetable beets, brassicas, legumes, horticultural species including fruits, berries, nuts, and shrubs, forest plantation species, cotton, sunflowers, and the like.

The invention may be used to control a broad range of agriculturally important weeds including monocotyledonous weeds and dicotyledonous weeds. It should be noted that in some situations a plant species may be considered a "weed" and in other situations it may be considered the crop or one of several crop species. For example, clover is generally considered an important pasture species but in a ryegrass seed cropping situation clover may be considered a weed. Conversely, ryegrass may be considered a weed in a clover seed crop.

Suitably, the synergistic herbicidal composition comprising active ingredients (A) and (B) may be used to control weeds including, but not limited to, alligator weed (Alternanthera philoxeroides), annual buttercup (Ranunculus parviflorus), annual poa (Poa annua), annual smartweed (Polygonium hydropiper), anoda weed (Anoda cristata), barley grass (Hordeum murinum), barnyard grass (Hordeum ssp.), Bermuda buttercup (Oxalis pes-caprae), black mustard (Brassica nigra), black nightshade (Solanum nigrum), black pigweed (Trianthema portulacastrum), blackgrass (Aiopecurus myosuroides), bladder ketmia (Hibiscus trionum), blue mustard (Chorispora teneila), bristly starbur (Acanthospermum hispidum), broad-leaved dock (Rumex obtusifoiius), bushy wallflower (Erysimum repandum), Californian stinkweed (Navarretia squarrosa), caltrop (Tribulus terrestris), cape weed (Arctotheca calendula), catchfly (Silene gallica), chickweed (Stellaria media), cleavers (Galium aparine), clustered dock (Rumex conglomeratus), coast fiddleneck (Amsinckia intermedia), cocklebur (Xanthium strumarium), common ragweed (Ambrosia artemisiifolia), common windgrass (Apera spica-venti), corn gromwell (Lithospermum arvense), cornbind (Polygonum convolvulus), couch (Elytrigia repens), creeping yellow cress (Rorippa sylvestris), crowfoot grass (Eieusine indica), curled dock (Rumex 13 crispus), dandelion (Taraxacum officinale), dayflower (Commelina ssp.), deadnettle (Lamium ssp.), devil's claw (Proboscidea louisianica), dove foot (Geranium molle), downy brome (Bromus tectorum), ducksalad (Heteranthera limosa), eclipta (Eclipta prostrata), false caper (Euphorbia terracina), false caper (Euphorbia terracina), false flax (Camelina ssp.), fathen (Chenopodium album), fiddle dock (Rumex pulcher), field pansy (Viola arvensis), flixweed (Descurainia sophia), fumitory (Fumaria sp), galinsoga (Galinsoga ssp.), giant buttercup (Ranunculus acris), giant panic (Panicum antidotale), giant ragweed (Ambrosia trifida), gnawed canary grass {Phalaris paradoxa), green bristle grass (Setaria viridis), green summer grass (Brachiaria miliiformis), hairy buttercup (Ranunculus sardous), hairy chess (Bromus commutatus), hairy vetch (Vicia villosa), hawkbit (Leontodon taraxacoides), hedge mustard (Sisymbrium officinale), hemp nettle (Galeopsis tetrahit), hemp sesbania (Sesbania exaltata), henbit (Lamium amplexicaule), innocent weed (Cenchrus ssp.), Italian ryegrass (Lolium multiflorum), Japanese brome (Bromus japanicus), Johnson grass (Sorghum halepense), lesser canary grass (Phalaris minor), mallow (Malva ssp.), mayweed (Anthemis ssp.), medick (Medicago ssp.), mimosa (Mimosa pigra), mint weed (Salvia reflexa), morningglory (Ipomoea ssp.), mouse-ear chickweed (Cerastium ssp.), nettle (Urtica urens), nipplewort (Lapsana communis), nodding thistle (Carduus nutans), nut grass (Cyperus rotundus), oxeye daisy (Leucanthemum vulgare), oxtongue (Picris echioides), pale willow weed (Polygonum lapathifolium), parsley piert (Aphanes inexspectata), paspalum (Paspalum dilatatum), Paterson's curse (Echium plantagineum), peach vine (Ipomea lonchophylla), penny cress (Thlaspi arvense), pepper grass (Lepidium virginicum), pigweed (Portulaca oleracea), plantain (Plantago ssp.), prairie grass (Bromus willdenowii), prickly lettuce (Lactuca serriola), ragwort (Senecio jacobaea), redroot (Amaranthus ssp.), redstem (Ammania ssp.), rice flatsedge (Cyperus iria), ripgut brome (Bromus diandrus), Russian thistle (Salsola iberica), scarlet pimpernel (Anagallis arvensis), scentless chamomile (Matricaria perforata), Scotch thistle (Cirsium vulgare), sesbania pea (Sesbania cannabina), sheep's sorrel (Acetosa acetosella), shepherd's purse (Capsella bursa-pastoris), sida (Sida ssp.), skeleton weed (Chondrilla juncea), small-flowered buttercup (Ranunculus parviflorus), sorrel (Rumex acetosa), sow thistle (Sonchus oleraceus), speedwell (Veronica ssp.), spiny emex (Emex australis), sprangle top (Leptochloa panicea), spring grass (Anthoxanthum odoratum), spurge (Euphorbia ssp.), spurrey (Spergula arvensis), squirrel tail grass (Hordeum jubatum), staggerweed (Stachys arvensis), stinkgrass (Eragrostis cilianensis), stinking Roger (Tagetes minuta), storksbill (Erodium cicutarium), subterranean clover (Trifolium subterraneum), summer grass (Digitaria ssp.), sunflower (Helianthus annuus), teaweed (Sida rhombifolia), Texas weed (Caperonia palustris), thorn apple (Datura stramonium), tick clover (Desmodium tortuosum), treacle mustard (Erysimum cheiranthoides), true cheat (Bromus secalinus), tumbling mustard (Sisymbrium altissimum), twin cress (Coronopus didymus), variegated thistle (Silybum marianum), velvetieaf (Abutilon theophrasti), vetch (Vicia sativa), volunteer oilseed rape (Brassica napus sssp. oleifera), western tansymustard (Descurainia pinnata), wild mustard (Sinapis arvensis), wild oat (Avena ssp.), wild radish (Raphanus raphanistrum), wild turnip (Brassica rapa sssp. sylvestris), willow weed (Persicaria persicaria), winged thistle (Carduus tenuiflorus), wireweed (Polygonum aviculare), witchgrass (Panicum capillare), yellow bristle grass (Setaria pumila), yellow gromwell (Amsinckia calycina), yellow nutsedge (Cyperus esculentus), yellow vine (Tribulus terrestris), and Yorkshire fog (Holcus lanatus).

The following examples and the particular proportions set forth are intended to be illustrative only and are thus non-limiting. 14 EXAMPLE 1. Diflufenican Flumetsulam Emulsifiable Concentrate Component Grams/litre Diflufenican 40 Flumetsulam N-Methyl pyrrolidone 150 Octyl pyrrolidone 635 Tensiofix B8426 60 Antarox B/848 60 Dissolve the diflufenican and flumetsulam in pre-warmed N-methyl pyrrolidone. Blend in octyl pyrrolidone, and the emulsifiers Tensiofix B8426 and Antarox B/848.

EXAMPLE 2. Diflufenican Flumetsulam Oil Dispersion Component Grams/litre Diflufenican 40 Flumetsulam Methyl oleate 548 Paraffinic oil 137 Tensiofix 869 Claytone HY 7.5 Tensiofix NTM 150 To the methyl oleate and paraffinic oil disperse with high shear mixing the Tensiofix 869 and Clayton HY. Add the emulsifier Tensiofix NTM then disperse the diflufenican and flumetsulam. Finally mill the mixture until the average particle size lies within the range from about 2 pm to about 5 pm.

EXAMPLE 3. Diflufenican Flumetsulam MCPB Emulsifiable Concentrate Component Grams/litre Diflufenican Flumetsulam 12.5 MCPB Acid 250 N-Methyl pyrrolidone 121 Octyl pyrrolidone 504 Tensiofix B8426 Antarox B/848 N-Butylamine 75 Dissolve the flumetsulam and diflufenican in pre-warmed N-methyl pyrrolidone. Blend in half of the octyl pyrrolidone, and the emulsifiers Tensiofix B8426 and Antarox B/848. Separately mix the N-butylamine and the remaining octyl pyrrolidone before dissolving the MCPB acid in this mixture with stirring. Finally combine the two liquids.

EXAMPLE 4. Diflufenican Flumetsulam Oil Dispersion Component Grams/litre Diflufenican Flumetsulam Methyl oleate 584 Paraffinic oil 146 Tensiofix 869 Bentone 38 Tensiofix NTM 150 To the methyl oleate and paraffinic oil disperse with high shear mixing the Tensiofix 869 and Bentone 38. Add the emulsifier Tensiofix NTM then disperse the diflufenican and flumetsulam. Finally mill the mixture until the average particle size lies within the range from about 2 pm to about 5 pm. 16 EXAMPLE 5. Diflufenican Flumetsulam Oil Dispersion Component Grams/litre Diflufenican 40 Flumetsulam Methyl oleate 560 Paraffinic oil 140 Tensiofix 869 Bentone 38 Tensiofix NTM 150 To the methyl oleate and paraffinic oil disperse with high shear mixing the Tensiofix 869 and Bentone 38. Add the emulsifier Tensiofix NTM then disperse the diflufenican and flumetsulam. Finally mill the mixture until the average particle size lies within the range from about 2 |jm to about 5 pm.

EXAMPLE 6. Diflufenican Flumetsulam Oil Dispersion Component Grams/litre Diflufenican Flumetsulam Methyl oleate 576 Paraffinic oil 144 Tensiofix 869 Bentone 38 Tensiofix NTM 150 To the methyl oleate and paraffinic oil disperse with high shear mixing the Tensiofix 869 and Bentone 38. Add the emulsifier Tensiofix NTM then disperse the diflufenican and flumetsulam. Finally mill the mixture until the average particle size lies within the range from about 2 pm to about 5 pm. 17 In the following examples, the synergistic weed controlling effects of compositions containing (A) at least one phytoene desaturase-inhibiting herbicide, and (B) at least one triazolopyrimidine herbicide and/or salts thereof, are demonstrated for various weeds by comparison of "Observed" percent control results with "Expected" percent control results based on the weed controlling effects of components (A) and (B) alone, calculated using the Colby formula: E = X + Y - (XY)/100, in which, X represents the % control by herbicide (A) at x gai/ha, Y represents the % control of growth by herbicide (B) at y gai/ha, and E represents the "Expected" % control by herbicides (A) + (B) at x + y gai/ha, respectively.

When the observed % control by (A) + (B) is greater than expected, the combination is synergistic. The term "% damage" is applied to the crop to distinguish crop from weed.

EXAMPLE 7. Weed control in young pasture.

An early summer sown pasture consisting of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) was sprayed 7 weeks after planting with diflufenican (DFF), flumetsulam (FLU), or the two herbicides combined, then assessed 58 days after application (DAA) for percent inhibition of growth with reference to untreated pasture by counting the number of Fathen (Chenopodium album) and Henbit (Lamium amplexicaule) plants per square metre in triplicate treated and untreated plots (Table 1). Ryegrass damage (stand reduction) was assessed 65 DAA. Typical label rates of DFF and FLU produced only partial control of Fathen and Henbit when used alone but the combination of DFF and FLU was synergistic and produced very acceptable control for weeds at this advanced stage of establishment. A synergistic effect was also observed on the ryegrass but the damage was well within acceptable limits (Table 1).

Table 1.

Treatment Fathen (% control) Henbit (% control) Ryegrass (% damage) DFF 100 gai/ha 60% 52% 0% FLU 52 gai/ha % 12% 7% DFF 100 gai/ha + FLU 52 gai/ha Expected 68% 58% 7% DFF 100 gai/ha + FLU 52 gai/ha Observed 80% 96% 13% Note Uptake Spraying Oil was included with treatments containing flumetsulam. 18 EXAMPLE 8. Weed control in young pasture.

A late autumn sown pasture consisting of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) was sprayed 3 weeks after planting with diflufenican (DFF), flumetsulam (FLU), or the two herbicides combined, then assessed 37 (DAA) for percent inhibition of growth with reference to untreated pasture by counting the number of Scrambling speedwell (Veronica persica) and Common chickweed (Stellaria media) plants per square metre in triplicate treated and untreated plots (Table 2). Clover damage was also assessed 37 DAA. Typical label rates of DFF and FLU produced only partial control of Scrambling speedwell and Chickweed when used alone but the combination was synergistic and produced very acceptable control for well established weeds. Clover is particularly susceptible to the bleaching effects of phytoene desaturase inhibitors such as DFF and a synergistic effect on clover damage was observed for the combination of DFF and FLU but the damage was well within acceptable limits (Table 2).

Table 2.

Treatment Speedwell (% control) Chickweed (% control) Clover (% damage) DFF 100 gai/ha 66.7% 33.3% 6.0% FLU 65 gai/ha 71.7% 46.7% 2.7% DFF 100 gai/ha + FLU 65 gai/ha Expected 90.6% 64.5% 8.5% DFF 100 gai/ha + FLU 65 gai/ha Observed 93.3% 86.7% .7% Note Uptake Spraying Oil was included with treatments containing flumetsulam.

EXAMPLE 9. Control of nettles and thistles in established pasture.

Established pasture was sprayed in winter with the composition of Example 1 at a rate corresponding to 40 gai/ha DFF and 25 gai/ha FLU, or with MCPB at 1,500 gai/ha, or with the combination, then assessed for percent chemical effect on burning nettle (Urtica urens), nodding thistle (Carduus nutans), variegated thistle (Silybum marianum) and Scotch thistle (Cirsium vulgare). The addition of MCPB increased the herbicidal effect on these particularly troublesome weeds and in all cases displayed a degree of synergistic interaction with the DFF-FLU mixture (Table 2). 19 Table 3. Percentage control of nettles and thistles.

Treatment Burning nettle 29 DAA Nodding thistle 37 DAA Variegated thistle 37 DAA Scotch thistle 37 DAA DFF+FLU 40+25 gai/ha 28.3% 60.0% 45.0% 70.0% MCPB 1,500 gai/ha 0.0% 18.0% .0% .0% DFF+FLU+MCPB 40+25+1,500 gai/ha Expected 28.3% 67.2% 61.5% 76.0% DFF+FLU+MCPB 40+25+1,500 gai/ha Observed 37.5% 80.0% 62.5% 80.0% EXAMPLE 10. Control of dock in established pasture.

Established pasture was sprayed in winter with either 40 gai/ha DFF and 25 gai/ha FLU, or DFF + FLU with MCPB at 500 gai/ha, then assessed for control of broad-leaved dock (Rumex obtusifolius). The addition of 500 g/ha MCPB increased the herbicidal effect on this difficult-to-control weed (Table 2).

Table 4. Percentage control of dock.

Dock Dock Treatment DAA 63 DAA DFF+FLU 40+25 gai/ha 12.5% 53.9% DFF+FLU+MCPB 40+25+500 gai/ha .0% 86.4% It will be appreciated that the compositions provided are examples only and that other herbicidal compositions may be contemplated comprising as active ingredients: (A) at least one phytoene desaturase-inhibiting herbicide and (B) at least one triazolopyrimidine herbicide and/or salts thereof, and optionally further comprising a third herbicidal active ingredient (C) consisting of at least one auxin herbicide.

Claims (23)

Having generally described this invention, including the best mode thereof, those skilled in the art will appreciate that the present invention contemplates the embodiments of this invention as defined in the following claims, and equivalents thereof. However, those skilled in the art will appreciate that the scope of this invention should not be measured merely by the specific embodiments exemplified herein. Those skilled in the art will also appreciate that more sophisticated technological advances will likely appear subsequent to the filing of this document with the Patent Office. To the extent that these later developed improvements embody the operative principles at the heart of the present disclosure, those improvements are likewise considered to come within the ambit of the following claims. The Invention may also broadly be said to consist in the parts, elements and features referred or indicated in the specification, individually or collectively, and any or all combinations of any of two or more parts, elements, members or features and where specific integers are mentioned herein which have known equivalents such equivalents are deemed to be incorporated herein as if individually set forth. Throughout the description and claims of the specification the word "comprise" or variations thereof are not intended to exclude other additives, components or steps. Kit of Parts It will also be understood that where a product, method or process as herein described or claimed and that is sold incomplete, as individual components, or as a "Kit of Parts", that such exploitation will also fall within the ambit of the invention. In a preferred embodiment the invention includes within its scope a kit of parts, the kit of parts providing for a herbicidal composition comprising in synergistic proportions in separate containers or as separate compartments within the same container a combination of: (A) diflufenican, and (B) flumetsulam and optionally (C) one or more auxin herbicides. 21 WHAT l/WE CLAIM IS:

1. A selective, synergistic herbicidal composition comprising as active ingredients: (A) diflufenican and (B) flumetsulam, characterised in that active ingredients (A) and (B) are present in synergistically effective ratios from about 20:1 to about 1:20 by weight and whereby the composition is applied at a rate ranging from about 50 gai/ha to about 1,500 gai/ha based on the combined weights of diflufenican and flumetsulam.

2. The herbicidal composition according to claim 1 wherein the weight ratio of (A) to (B) is from about 10:1 to about 1:10.

3. The herbicidal composition according to claim 1 or 2 wherein the weight ratio of (A) to (B) is from about 5:1 to about 1:5.

4. The herbicidal composition according to any one of claims 1 to 3 comprising 0.1% to 80% of active ingredient (A) and 0.1% to 80% of active ingredient (B) on a weight/weight basis or a weight/volume basis.

5. The herbicidal composition according to any one of the preceding claims further comprising of one or more auxin herbicides comprising 2,4-D, 2,4-DB, 4-CPA, benazolin, MCPA, MCPB, quinclorac, and esters and salts thereof.

6. The herbicidal composition according to claim 5 wherein the one or more auxin herbicides is 2,4-DB, 4-CPA and MCPB, and salts and esters thereof.

7. The herbicidal composition according to claim 5 whereby the auxin herbicide is applied at a rate ranging from about 50 gai/ha to about 2,000 gai/ha.

8. The herbicidal composition according to any one of claims 5 to 7 comprising 0.1% to 90% auxin herbicide on a weight/weight basis or a weight/volume basis.

9. The herbicidal composition according to any one of the preceding claims wherein the composition is formulated as a concentrate, an emulsion, a suspo-emulsion, a suspension, an oil dispersible suspension, a water dispersible granule, a solution or a capsule suspension. 22

10. The herbicidal composition according to any one of the preceding claims further comprising 1 to 99% on a weight/weight basis or a weight/volume basis of customary formulation additives.

11. The herbicidal composition according to any one of the preceding claims further comprising a solid or liquid carrier.

12. A method for the selective control or suppression of weeds which comprises applying to plants, parts of plants, plant seeds or to soil a herbicidally effective amount of the synergistic composition accordingly to any of the preceding claims characterised in that active ingredients (A) diflufenican and (B) flumetsulam are present in synergistically effective ratios from about 20:1 to about 1:20 by weight and whereby the composition is applied at a rate ranging from about 50 gai/ha to about 1,500 gai/ha based on the combined weights of (A) diflufenican and (B) flumetsulam.

13. The method according to claim 12 wherein the weight ratio of active ingredient (A) to active ingredient (B) is from about 10:1 to about 1:10.

14. The method according to claim 12 or claim 13 wherein the weight ratio of active ingredient (A) to active ingredient (B) is from about 5:1 to about 1:5.

15. The method according to any one of claims 12 to 14 wherein the herbicidal composition further comprises of one or more auxin herbicides comprising 2,4-DB, 4-CPA and MCPB, and salts and esters thereof.

16. The method according to claim 15 whereby the auxin herbicide is applied at a rate ranging from about 50 gai/ha to about 2,000 gai/ha.

17. The method according to any one of claims 12 to 16 wherein the herbicidal composition is applied at any stage of the crop cycle.

18. The method according to any one of claims 12 to 17 wherein the herbicidal composition is diluted with water before being applied to plants, parts of plants, plant seeds or to soil by conventional means including spraying, sprinkling and wicking. 23

19. The method according to any one of claims 15 to 18 wherein diflufenican and flumetsulam, or diflufenican, flumetsulam and the auxin herbicide may be applied simultaneously or sequentially.

20. The method according to any one of claims 15 to 19 wherein diflufenican and flumetsulam, or diflufenican, flumetsulam and the auxin herbicide may be tank mixed prior to application.

21. The method according to any one of claims 12 to 20 wherein the selective, synergistic herbicidal composition is used to selectively control monocotyledonous and dicotyledonous weeds.

22. A selective, synergistic herbicidal composition according to any one of claims 1 to 11 substantially hereinbefore described with reference to any one of the accompanying examples.

23. A method of selectively controlling weeds according to any one of claims 12 to 21 substantially as hereinbefore described with reference to any one of the accompanying examples. PIPERS, Patent Attorneys for Zelam Limited