WO2019140163A1 - Herbicidal compositions comprising a capsule suspension formulation of pethoxamid - Google Patents

Abstract

The present application discloses herbicidal compositions comprising a capsule suspension formulation of microencapsulated pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine, diethyltriamine, triethylenetetramine, 1,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate, optionally combined with a safener such as benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl or combinations thereof. Methods for controlling undesired vegetation like weeds are also disclosed.

Description

HERBICIDAL COMPOSITIONS COMPRISING A CAPSULE SUSPENSION

FORMULATION OF PETHOXAMID

FIELD OF THE INVENTION

This invention relates to herbicidal compositions comprising capsule suspensions of pethoxamid and optional safeners, and to methods for controlling weeds.

BACKGROUND

In the case of crop protection compositions, like herbicidal compositions, it is desirable in principle to increase the specific activity of an active compound and the reliability of the effect. It is particularly desirable for herbicidal compositions to control harmful plants or weeds (commonly referred to herein as“weeds”) effectively, but at the same time not compromise crop safety. Also desirable is a broad spectrum of activity allowing the simultaneous control of weeds.

With many highly effective herbicides, there is the problem that their compatibility with useful plants, in particular dicotyledonous crop plants, such as cotton, soybeans, oilseed rape and graminaceous plants, such as barley, millet, com, rice, wheat, and sugar cane, is not always satisfactory, i.e. in addition to the weeds, the crop plants, too, are damaged on a scale that cannot be tolerated. By adjusting the application rates, the injury to useful plants can be reduced or eliminated, however, naturally, the extent of the control of weeds may be reduced.

It is known that in some cases joint application of specifically acting herbicides with organic active compounds, some of which may also have herbicidal activity, allows better crop plant compatibility to be achieved. In these cases, the active compounds act as antidotes or antagonists and are also referred to as“safeners”, because they reduce or even prevent damage to the crop plants. One such safener is benoxacor which has been used to safen chloroacetamide herbicide such as S-metolachlor (see U.S. Patent 4,601,745). Another safener is dichlormid (see U.S. Patent 4,053,297) is used to provide safety to crops from chloroacetamide herbicides.

The herbicidal active compound pethoxamid is known from U.S. Patent 4,895,587 and is generally used to control grass and broad-leaved weeds such as foxtail species, crabgrass species, barnyardgrass, ladysthumb, bindweed, pigweed species, and common lambsquarters in various crops including corn, winter oil seed rape, soybeans, peas and beans, and tobacco.

Previously, pethoxamid has typically been formulated in emulsifiable concentrates, which have high levels of volatile organic compounds (VOCs) and may have undesirable crop injury due to higher uptake of herbicide by the useful plant. The emulsifiable concentrates also can exhibit poor performance on weeds when held for extended periods in a spray tank and may be difficult to reconstitute after exposure to cold temperatures.

US 2016/143281 Al discloses various formulations of pethoxamid and picloram, including capsule suspensions comprising pethoxamid in microcapsules prepared from a toluene diisocyanate/polymethylene -polyphenylisocyanate mixture and l,6-diaminohexane.

It is desirable to provide improved formulations for pethoxamid that eliminate these problems and provide improved herbicidal performance against weeds with reduced crop injury.

SUMMARY OF THE INVENTION

This invention relates to herbicidal compositions comprising a capsule suspension formulation of pethoxamid having reduced crop injury relative to conventional emulsifiable concentrate formulations of pethoxamid. In particular it relates to a herbicidal composition comprising a capsule suspension formulations of microencapsulated pethoxamid in which the pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine, diethyl triamine, triethylenetetramine, l,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate, such as polymethylene polyphenyl isocyanate, in the absence of toluene diisocyanate. The capsule suspension formulations can be used to minimize injury (<10%) to desirable plants, while maintaining a satisfactory level of herbicidal activity against target weed species. Notably, the polyurea is prepared in the absence of toluene diisocyanate, which forms a linear, more porous polymer structure for microcapsules.

It is further believed that in some embodiments, herbicidal compositions with reduced oral toxicity and/or improved handler safety can be provided.

The invention also relates to herbicidal compositions in the form of a capsule suspension composition comprising a herbicidally effective amount of pethoxamid; and one or more safeners; and a liquid carrier and/or one or more surfactants and, if desired, one or more further auxiliaries customary for formulating crop protection agents.

The invention further relates to herbicidal compositions formulated as a capsule suspension composition comprising pethoxamid and one or more safeners wherein the pethoxamid and the safener(s) are combined in microcapsules, and a liquid carrier and/or one or more surfactants and, if desired, one or more further auxiliaries customary for formulating crop protection agents.

The invention still further relates to a product for preparing a herbicidal composition, comprising in a first container a capsule suspension formulation of pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine, diethyl triamine, triethylenetetramine, l,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate; and comprising in a second container a composition comprising one or more safeners and/or one or more second herbicides.

Preferably, the capsule suspension formulations of pethoxamid are combined with one or more safeners, in particular wherein at least one safener (especially all safeners) are selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof.

The invention further relates to a method for controlling weeds comprising exposing the weeds to a herbicidally effective amount of herbicidal composition as defined herein, or of a herbicidal composition prepared from the product defined herein.

Alternatively, the invention provides a method for controlling undesired plant growth comprises applying to the locus where such control is desired a herbicidally effective amount of herbicidal composition as defined herein, or of a herbicidal composition prepared from the product defined herein.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

The term“pethoxamid” is used herein as an alternative or common name of 2-chloro- N-(2-ethoxyethyl)-N-(2-methyl-l-phenylprop-l-enyl)acetamide. The term“benoxacor” is used herein as an alternative or common name of 4-(dichloroacetyl)-3,4-dihydro-3-methyl- 2H-l,4-benzoxazine. The term“dichlormid” is used herein as an alternative or common name of N,N-diallyldichloroacetamide. The term“isoxadifen” is used herein as an alternative or common name of 4,5-dihydro-5,5-diphenyl-l,2-oxazole-3-carboxylic acid or a salt thereof. The term“isoxadifen-ethyl” is used herein as an alternative or common name of ethyl 4,5- dihydro-5, 5-diphenyl- l,2-oxazole-3-carboxylate.

The term“weed” means and includes any plant which grows where not wanted.

The term“herbicide product” refers to a compositional mixture that is produced, sold, or used in a field in order to kill or otherwise inhibit the growth of unwanted plants such as, but not limited to, deleterious or annoying weeds, broadleaf plants, grasses, and sedges; and can be used for crop protection, edifice protection or turf protection. The term“herbicide product” includes the end-use herbicidal product. This composition can be a pure compound, a solution of chemical compounds, a mixture of chemical compounds, an emulsion, a suspension, a solid-liquid mixture, or a liquid- liquid mixture. The term“herbicide product” also refers to the product that passes through the commercial channels from the manufacturer to the ultimate end user who can either apply the herbicide product to the affected field as sold, or suspend, dissolve or dilute the herbicide product, and/or mix it with other excipients and/or other herbicide products.

The term“herbicidal composition” refers to a herbicide product as defined above and in addition thereto to any composition that comprises one or more herbicidally active ingredients. This composition can be a solution or a mixture like a suspension, dispersion, or powder. Further, the definition of the term“herbicidal composition” also refers to a product intended for use in manufacturing, or any product intended for formulation or repackaging into other herbicide products.

The term“active ingredient” refers to the specific compound or material that produces a biological effect, in particular a herbicidal effect against weeds, i.e. a“herbicide”, or that reduces or prevents plant damage from another active ingredient (e.g. a herbicide), i.e. a “safener”.

The term“herbicidally effective amount” denotes an amount of the herbicidal composition or of the combinations according to the invention, which is sufficient for providing one or more of the effects: (i) herbicidal activity, (ii) broader activity spectrum, or (iii) extended time frame, wherein a“herbicidal effect” on unwanted plant growth include one or more of the effects of necrosis, death, growth inhibition, reproduction inhibition, inhibition of proliferation, and removal, destruction, or otherwise diminishing the occurrence and activity of unwanted plants. In a preferred embodiment, the herbicidally effective amount is sufficient for to control weeds in the presence of useful plants while at the same time not resulting in unacceptable damage to the treated useful plants. Such an amount may be selected within a broad range and is dependent on various factors, such as the weed species to be controlled, the treated useful plant, the climatic conditions, soil conditions, and the specific combination used.

“Control” means to kill undesired plant(s), reduce or retard its growth or prevent or reduce its germination. Generally, the plants to be controlled are weeds. Weeds can also include plants which may be considered crop plants but which are growing outside a crop area (“escapes”), or which grow from seed left over from a previous planting of a different crop (“volunteers”). Such volunteers or escapes may be tolerant to certain other herbicides.

The term“microcapsule” as used herein, refers to a generally spherical microparticle consisting of a polymeric shell comprising a wall-forming material and encapsulated active ingredient(s) located within the shell. This term is distinct from other spherical granules of the active substance dispersed in solvent or a polymer. The microcapsules can comprise a single polymeric shell, wherein the active substance is located within the inner core or center of the microcapsule. The microcapsules can also refer to a "multilayer microcapsule" comprising an inner core microcapsule and one or more outer polymeric shells. As used herein the term“wall-forming polymer” refers to a polymer or polymerizable monomeric units or a combination of two or more different polymers or polymerizable monomeric units, which form a component of the polymeric shell of the microcapsules. The term“polymer shell” refers to a layer containing the wall-forming polymer and, optionally, other components such as a plasticizer, oil, pore-forming components and/or a mineral.

The term“encapsulated together” means that pethoxamid and an additional active ingredient, such as a safener and/or a second herbicide, are contained in the same microcapsules.

Herbicidal compositions

One aspect of the invention relates to a herbicidal composition comprising a capsule suspension formulation of pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea. Preferably, the polyurea is prepared from one or more amines selected from ethylenediamine, diethyltriamine, triethylenetetramine, l,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate. In some preferred embodiments, the herbicidal composition further comprises one or more safeners. Suitable safeners may be those selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, cloquintocet-mexyl, cyometrinil, cyprosulfamide, dicyclonon, dietholate, fenchlorazole, fenclorim, flurazole, fluxofenim, furilazole, mefenpyr-diethyl, mephenate, naphthalic anhydride, oxabetrinil, 4-(dichloroacetyl)-l-oxa-4-azaspiro[4,5]decane (AD 67, CAS 71526-07-3), 4-carboxy-3,4-dihydro-2H-l-benzopyran-4-acetic acid (CL 304,415, CAS 31541-57-8), 2,2-dichloro-N-[2-oxo-2-(2-propenylamino)ethyl]-N-2- propenylacetamide (DKA-24, CAS 97454-00-7), 2-dichloromethyl-2-methyl-l,3-dioxolane (MG 191, CAS 22052-63-7), 3-(dichloroacetyl)-2,2,5-trimethyl-l,3-oxazolidine (RD 29148, CAS 52836-31-4), and l-dichloroacetylazepane (TI-35, CAS 64661-12-7), and combinations thereof.

In embodiments hereof, at least one safener is selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof, for example such that all safener(s) are selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof.

In some embodiments, pethoxamid and the one or more safeners selected from benoxacor, dichlormid, isoxadifen and isoxadifen-ethyl, and combinations thereof, are the sole active ingredients present in the herbicidal compositions, or in the products herein described and applied in the methods and uses herein described.

Pethoxamid is typically present in about 0.1% to about 60% by weight of the total herbicidal composition, such as from a lower limit of 0.1, 1, 5, 10, 20 or 30% by weight to an upper limit of 40, 45, 50 or 60% by weight of the total herbicidal composition.

The one or more safeners, when present, are in total typically present in about 0.1 to about 10% by weight of the total herbicidal composition, such as from a lower limit of 0.1, 0.5, 1% by weight to an upper limit of 3, 5 or 10% by weight of the total herbicidal composition.

In herbicidal compositions comprising pethoxamid and safener(s), pethoxamid and the safener(s) are typically present in a weight ratio (pethoxamid:safener(s)) of in the range of 1:1 to 500:1, preferably 1:1 to 250:1, in particular 1: 1 to 150:1, particularly preferably 1:1 to 100:1, more preferably 2:1 to 70:1; even more preferably 10: 1 to 70:1 and most preferably 10:1 to 40:1, depending on the safener used. The same ratios are useful for use in the methods herein described. In some embodiments, the herbicidal compositions include those wherein the pethoxamid is encapsulated together with the safener(s) as described herein.

Alternatively, the herbicidal compositions include those wherein the pethoxamid is encapsulated as described herein, and the safener(s) is not encapsulated with the pethoxamid.

In embodiments of the invention, the herbicidal compositions comprise

microencapsuled pethoxamid (as further described hereinabove) and in addition thereto one or more second herbicides. In some embodiments hereof, pethoxamid and at least one second herbicide are encapsulated together.

The second herbicide may be selected from isoxazolidinones such as clomazone, 2- (2,4-dichlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone or 2-(2,5- dichlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone; carotenoid biosynthesis inhibitors, for example beflubutamid (including optically enriched forms thereof), diflufenican, fluorochloridone, fluridone, isoxachlortole, ketospiradox, flurtamone, norflurazon or amitrole; auxin herbicides, for example pyridinecarboxylic acids, such as clopyralid, fluroxypyr, triclopyr or picloram; photosystem II inhibitors such as triazines such as atrazine, cyanazine, simazine, or terbuthylazine; HPPD inhibitors such as benzofenap, isoxaflutole, benzobicyclon, pyrazolynate, pyrazoxyfen, topramezone, or preferably triketones such as mesotrione, sulcotrione (chlormesulone), or tembotrione; protoporphyrinogen oxidase (PPO) inhibitors such as triazolinones such as azafenidin, carfentrazone-ethyl or sulfentrazone; or acetamides such as diphenamid, napropamide (including napropamide-M) or naproanilide, Preferably, the second herbicide comprises clomazone, 2-(2,4-dichlorophenyl)methyl-4,4- dimethyl-3-isoxazolidinone, mesotrione, tembotrione, beflubutamid, sulfentrazone, picloram, terbuthylazine, napropamide, or napropamide-M. In one embodiment, the second herbicide comprises napropamide or napropamide-M. In another embodiment, the second herbicide comprises mesotrione. In another embodiment, the second herbicide comprises tembotrione. In still another embodiment, the second herbicide is beflubutamid. In some embodiments, the microcapsule may further comprise a safener, preferably selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof. For example, pethoxamid may be combined with triketones such as mesotrione, sulcotrione or tembotrione in the presence of isoxadifen or isoxadifen-ethyl.

When pethoxamid and one or more second herbicides are encapsulated together the ratio of pethoxamid to the second herbicide (or combined amount of second herbicides) in typically in the range of 1:50 to 50:1, preferably 1:10 to 10:1, or 1:5 to 5: 1, or 1:3 to 3:1, depending on the second herbicide used. When pethoxamid and the second herbicide is used together with a safener, the weight ratio of pethoxamid and any safener is as otherwise described herein.

The herbicidal composition may further comprise at least one liquid carrier and/or one or more surfactants. Such liquid carriers and/or surfactants are those being part of the capsule suspension formulation, e.g. those being included in the capsule suspension formulation upon the preparation of the microencapsulated pethoxamid as describe further below.

Also, the herbicidal compositions typically comprise auxiliaries customary for formulating crop protection agents. Such auxiliaries may include viscosity modifiers, preservatives, pH modifiers, antifreeze agents, colorants, and antifoam agents.

Viscosity modifiers (e.g. thickeners) are included to help prevent settling of the microcapsules and other suspended components. Viscosity modifiers can include a wide variety of components including but not limited to glycerine, clays, gums, and modified cellulose derivatives. Examples of thickeners (i.e. compounds which impart to the formulation modified flow properties, i.e. high viscosity in the state of rest and low viscosity in motion) include polysaccharides, such as carrageenan, xanthan gum, guar gum, gum Arabic, gum tragacanth, polyox, preferably xanthan gum such as Kelzan^® from Kelco or Rhodopol^® 23 (Rhone Poulenc), a magnesium aluminum silicate or smectite (bentonite and hectorite are members of the smectite group) such as Veegum^® (from R. T. Vanderbilt), or organic and inorganic sheet minerals, such as Attaclay^® (from Engelhardt). The viscosity modifier may be present in about 0.01 to about 15% by weight of the total formulation preferably 0.1 to 5% by weight.

In some embodiments, the viscosity of the final product may be adjusted to a measurement ranging from 200 and to 5000 Centipoises (mPas) with spindle #3, measured with Brookfield LVT Rotational Viscometer.

Suitable preservatives, biocides, bacteriocides and the like include but are not limited to C ₁₂ to C₁₅ alkyl benzoates, alkyl p^_hydroxybenzoates, aloe vera extract, ascorbic acid, benzalkonium chloride, benzoic acid, benzoic acid esters of C₉ to C₁₅ alcohols, butylated hydroxytoluene, butylated hydroxyanisole, tert-butylhydroquinone, castor oil, cetyl alcohols, chlorocresol, citric acid, cocoa butter, coconut oil, diazolidinyl urea, diisopropyl adipate, dimethyl polysiloxane, DMDM hydantoin, ethanol, ethylenediaminetetraacetic acid, fatty acids, fatty alcohols, hexadecyl alcohol, hydroxybenzoate esters, iodopropynyl

butylcarbamate, isononyl iso-nonanoate, jojoba oil, lanolin oil, mineral oil, oleic acid, olive oil, parabens, poly ethers, polyoxypropylene butyl ether, polyoxypropylene cetyl ether, potassium sorbate, propyl gallate, silicone oils, sodium propionate, sodium benzoate, sodium bisulfite, sorbic acid, stearic fatty acid, sulfur dioxide, and derivatives, esters, salts and mixtures thereof. Examples of bactericides are bactericides based on dichlorophen and benzyl alcohol hemiformal (Proxel^® from Lonza or Acticide^® RS from Thor Chemie and Kathon^® MK from Rohm & Haas), and also isothiazolinone derivates, such as alkylisothiazolinones and benzisothiazolinones (Acticide MBS from Thor Chemie).

Preservatives include sodium o-phenylphenate, 5-chloro-2-methyl-4-isothiazolin-3- one, 2-methyl-4-isothiazolin-3-one (Kathon^®) and l,2-benzisothiazolin-3-one.

Suitable pH modifiers include acetic acid, hydrochloric acid, citric acid, phosphoric acid, buffers and the like.

Examples of antifreeze agents include ethylene glycol, propylene glycol, urea, glycerol, or water-soluble salts such as calcium chloride or sodium nitrate.

Examples of colorants are both sparingly water-soluble pigments and water-soluble dyes. Examples include the dyes known under the names Rhodamin B, C.I. Pigment Red 112 and C.I. Solvent Red 1, and also pigment blue 15:4, pigment blue 15:3, pigment blue 15:2, pigment blue 15:1, pigment blue 80, pigment yellow 1, pigment yellow 13, pigment red 112, pigment red 48:2, pigment red 48:1, pigment red 57:1, pigment red 53:1, pigment orange 43, pigment orange 34, pigment orange 5, pigment green 36, pigment green 7, pigment white 6, pigment brown 25, basic violet 10, basic violet 49, acid red 51, acid red 52, acid red 14, acid blue 9, acid yellow 23, basic red 10, and basic red 108.

In other embodiments, the formulation of the invention may further contain an antifoam agent, and/or a pore-making agent.

Examples of antifoams are silicone emulsions (such as, for example, Silikon^® SRE, Wacker or Rhodorsil^® from Rhodia), long-chain alcohols, fatty acids, salts of fatty acids, organofluorine compounds and mixtures thereof.

The amounts of post-encapsulation additives to be added may be selected from one or more of 0.75 to 6.5% by weight of propylene glycol, 0.05 to 0.30% by weight of xanthan gum, 0.25 to 0.50% by weight of smectite clay, and 0.5 to 6.0% by weight of one or more surfactants, each weight percent relative to the weight of the formulation after addition of the stabilizers. The herbicidal compositions according to the invention are also suitable for controlling vegetation on non-crop areas very efficiently, especially at high rates of application, and they act against broadleaf weeds and grass weeds (e.g. yellow nutsedge) in crops without causing any significant or unacceptable damage to the crop plants.

It should be understood that in the embodiments described herein where the herbicidal compositions (and the products (see further below)) further comprises one or more safeners and/or one or more second herbicides, one or more or all of such safener(s)/second herbicide(s) may be encapsulated together with pethoxamid, or one or more or all of such safener(s)/second herbicide(s) may be encapsulated separately by techniques described for the encapsulation of pethoxamid based on essentially the same materials, or one or more of all of such safener(s)/second herbicide(s) may be present in the herbicidal composition in non-encapsulated form, or in a separate composition in encapsulated or non-encapsulated form.

Preparation of herbicidal compositions

The polymer shell of the microcapsules comprising pethoxamid (and possibly also safener(s) and/or second herbicide(s)) comprises an urea polymer made by isocyanate polymerization, wherein one or more isocyanates including a polymeric isocyanate react with one or more amines to form a polyurea. The isocyanate molecules are usually contained within the oil phase in the processes described herein. The amino groups may be generated in the oil phase or at the oil-water interface. In one embodiment, the polymerization is facilitated by a surface modifying compound that may react with the isocyanate moiety. Suitable isocyanates include but are not limited to isomers and derivatives of biphenylene diisocyanates, polymeric isocyanates such as polymethylenepolyphenylene isocyanates (PMPPI), polymethylenepolyphenyl isocyanate containing 4,4'-methylene bisphenyl isocyanate, aliphatic acyclic isocyanates such as hexamethylene diisocyanate (HMDI), cyclic aliphatic isocyanates such as isophorone diisocyanate (IPDI) and trimers of HMDI, or mixtures thereof. Amines that can react with the isocyanates to form polyureas may include ethylenediamine, diethyltriamine, triethylenetetramine, l,6-hexanediamine, or a mixture thereof. Preferably the amine is l,6-hexanediamine (hexamethylene diamine).

Other polymers, either biodegradable or non-biodegradable, may also be employed in the structure of the microcapsule shell. They include synthetic cellulose or other cellulose moieties such as cellulose acetate butyrate, cellulose acetate phthalate, carboxylethyl cellulose, cellulose triacetate, and cellulose sulfate sodium salt, polymers of acrylic acid, methacrylic acid or copolymers or derivatives thereof including esters, poly(methyl methacrylate), poly(ethyl methacrylate), poly (butylmethacry late), poly(isobutyl

methacrylate), poly(hexylmethacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate), and poly(octadecyl acrylate), polyacrylic acids, poly(butyric acid), poly(valeric acid), and poly(lactide-co-caprolactone), copolymers and blends thereof.

Examples of non-biodegradable polymers include ethylene vinyl acetate,

poly(meth)acrylic acid, polyamides, copolymers and mixtures thereof. Examples of biodegradable polymers include polymers of hydroxy acids such as lactic acid and glycolic acid polylactide, polyglycolide, polylactide co glycolide, and copolymers with PEG, poly anhydrides, poly(ortho)esters, polyurethanes, poly(butyric acid), poly(valeric acid), and poly(lactide-co-caprolactone).

In at least one embodiment, the microcapsules of the invention are designed to may be sufficiently robust or to be dried and then re-dispersed. In general, it is preferred that the weight ratio of the wall material to the microcapsule (core plus wall) is greater than 1% by weight. Typically, the weight ratio of the wall material to the microcapsule will be from 1 % to 70%, such as from a lower limit of 1, 3, or 5% by weight to an upper limit of 10, 15, 20,

25, 30, 40 or 50% by weight.

The microcapsules comprising pethoxamid included in the herbicidal compositions according to this invention may be prepared by any of the known microencapsulation techniques.

However, they are preferably prepared by interfacial polymerization processes. In these processes, a relatively water-insoluble (generally termed an "organic" or "oil") liquid phase is prepared that contains pethoxamid and optionally one or more additional herbicides, and/or optionally one or more safeners, optionally dissolved or suspended in a solvent, optionally one or more surfactants and one or more monomers that will become polymerized to form a polymeric shell for the capsule. The organic phase is then added to an aqueous phase with agitation, forming a dispersion or emulsion of organic (discontinuous) phase droplets in the aqueous (continuous) phase. The aqueous phase may contain one or more surfactants, protective colloids, and other ingredients as known in the art. The dispersion is then subjected to conditions (usually agitation and heating) so as to cause the monomer or monomers contained in the organic phase droplets to polymerize at the interface between the organic and aqueous phases, forming shells of polymer around the droplets. The result is a suspension of microcapsules in the aqueous phase. This suspension may be suitable for application to the locus to control undesirable vegetation, or it may be modified by additional agriculturally suitable formulants prior to application.

In an embodiment, the reaction leading to the formation of the polymeric shell is initiated by heating the emulsion to an elevated temperature at which point some isocyanate groups are hydrolyzed at the interface to form amines, which in turn may react with unhydrolyzed isocyanate groups to form the polyurea microcapsules. In another embodiment, diamines and/or polyamines are added to the emulsion, which then react with the isocyanates to form the polyurea microcapsule.

Notably, the capsule suspension can be prepared by a process involving the following steps: (a) providing an aqueous phase containing an emulsifier, preferably a partially hydrolyzed polyvinyl alcohol; and optionally at least one of an antifoam agent, or a viscosity modifier/stabilizer such as xanthan gum, or other water soluble formulant; (b) providing a water immiscible phase comprising pethoxamid, polymerizable isocyanate such as polymeric isocyanates such as polymethylenepolyphenyleneisocyanates (PMPPI), polymethylene polyphenyl isocyanate containing 4,4' methylene bisphenyl isocyanate, and optionally a safener selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof, with or without a hydrocarbon solvent or water-insoluble carrier; (c) emulsifying the water immiscible phase in the aqueous phase to form a dispersion of water-immiscible droplets throughout the aqueous phase; (d) agitating the dispersion while adding to it, either neat or in aqueous solution, an amine such as ethylenediamine, diethyltriamine,

triethylenetetramine, l,6-hexanediamine, or mixtures thereof, thus forming a polyurea shell wall around the water-immiscible droplets. Notably, the polyurea is prepared in the absence of toluene diisocyanate, which forms a linear, more porous polymer structure for

microcapsules. Once the microcapsules are formed, the suspension is cured by moderate heating, after which one or more stabilizing agents, such as propylene glycol, xanthan gum, smectite clay, or an ionic dispersing agent such as a sulfonate of an alkyl napthalene, may be added. The addition of these materials after encapsulation and curing to adjust viscosity and suspensibility is not seen to have any negative effect on the herbicidal efficacy of the pethoxamid in the formulation. In such embodiment, the shell wall of the microcapsules is a polyurea formed via the emulsion polymerization process.

The aqueous phase may contain 0.3 to 3.0%, preferably 0.8 to 2.0%, by weight of one or more emulsifiers, e.g., polyvinyl alcohol, 0.05 to 0.20%, preferably 0.06 to 0.15%, by weight of the xanthan gum viscosity modifier/stabilizer, if it is used, and 0.1 to 1.0%, preferably 0.4 to 0.9%, by weight of an antifoam agent, if it is used.

The water-immiscible phase may comprise 60 to 85%, preferably 65 to 80%, by weight of pethoxamid, an amount of polymeric isocyanate such that the weight ratio of pethoxamid to isocyanate is in the range of 1: 1 to 20:1, preferably 3: 1 to 15:1, and optionally a solvent, such as an aromatic hydrocarbon solvent, for the two solutes. However, use of solvent is optional in the preparation of formulations containing more than about one kilogram of pethoxamid per four liters of formulation. In such preparations a small amount of solvent may still be used to depress the melting point.

In some embodiments, one can optionally employ a non-aqueous solvent or carrier to suspend or dissolve the substantially water-insoluble active ingredients. Solvents or carriers include any non-aqueous solvents that are capable of suspending or dissolving pethoxamid, but not chemically react with pethoxamid.

Examples of such liquid carriers or solvents include vegetable oils such as, soybean oil, epoxidized soybean oil, coconut oil, olive oil, safflower oil, cotton seed oil, corn oil, rape seed oil and the like, mineral oil fractions of medium to high boiling point, such as kerosene and diesel oil, or coal tar oils. Other such liquids include aliphatic, cycloaliphatic, or aromatic hydrocarbons such as dodecane, n-decane, n-hexane, cyclohexane, toluene, benzene, and the like for example paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives, alkylated benzenes and their derivatives; aliphatic or aromatic alcohols such as heptanol, octanol, and the like, ketones such as cyclohexanone, or combinations of any two or more thereof. Other examples of suitable solvents include petroleum distillates, such as heavy aromatic naphthalene-depleted solvents (Aromatic 200, 100, 150) having a boiling point in the range of 100-400 °C.

The amine solution will ordinarily contain 10 to 100%, preferably 30 to 50%, by weight of ethylenediamine, diethylenetriamine, triethylenetetramine, l,6-hexanediamine, or optionally a mixture of the polyfunctional amines, with ethylenediamine being used only in a mixture. A preferred amine is l,6-hexanediamine (hexamethylene diamine). In at least another embodiment, the polymerization reaction is allowed to proceed so as to form a microcapsule wall thickness that is suitable for the present intended purpose. In one embodiment, altering the concentration of the polymeric isocyanate in the oil phase and its respective ratio to the amine moiety can lead to different wall thickness. For example, when the concentration of polymethylene polyphenyl isocyanate containing 4,4'-methylene bisphenyl isocyanate (PAPI^® 27) is 3.9% in the oil phase and the aminedsocyanate (PAPI^® 27) ratio is 0.89 to 1.0 respectively, then the wall thickness of the resulting microcapsules is much less compared to a scenario wherein the isocyanate is present in amount of 7.5% in the oil phase, with the same aminedsocyanate ratio. Similarly, altering the aminedsocyanate ratio impacts the final wall thickness. Any such alterations unexpectedly lead to unique physical and physiochemical properties of such microcapsules that are customized towards active ingredients of choice.

In at least one embodiment, the microcapsules are prepared in such manner to provide a microcapsule shell thickness ranging from 5 nanometers to 1000 nanometers. In a more preferred embodiment, the microcapsule has a shell wall thickness ranging from 10 to 200 nanometers, alternatively 15-100 nanometers resulting in microcapsules thereby reducing the amount of buildup on the treating equipment.

In some embodiments, the microcapsules are prepared following the general steps of (1) making an organic phase by mixing pethoxamid and optionally an additional active ingredient (like safener(s) and/or second herbicide(s)) with the isocyanate monomers, optional solvents/oils, and other additives; (2) making an emulsion of the organic phase in an aqueous phase by using selected surfactants; (3) adding the amine monomers to activate interfacial polymerization; (4) and allowing interfacial polymerization for a sufficient amount of time, preferably between 5-24 hours at a preset temperature and pH 2-5. In another aspect of the invention, interfacial polymerization occurs at a temperature ranging from 25 to 65 °C. In a more preferred embodiment, the interfacial polymerization occurs at a temperature ranging from 45 to 60 °C.

The emulsification step requires high shear mixing to give small droplets of the immiscible oil phase in the aqueous phase. Factors that influence droplet size, which determines the eventual size of the microcapsules, as well as the stability of the emulsion, include speed and length of mixing, the type and amount of surfactant, solvent, temperature, and viscosity, as well as the xanthan gum when used. Selection of the appropriate microcapsule size to achieve the purposes of the invention requires a balance between competing factors. In general, increasing microcapsule size decreases volatility, but also decreases suspensibility of the particles, while decreasing size yields better suspensibility, but higher volatility. For the purposes of this invention the average size of the microcapsules is 5 to 50 microns, preferably 5 to 30 microns. The operating conditions to yield microcapsules of a desired size will depend on the emulsifying equipment used, and the adjustment to determine the proper conditions is well within the skill of the art.

In contrast to the conditions of the emulsification step, agitation during the amine addition should be gentle. Stirring is continued while the suspension is cured by heating to a temperature of 35 to 60, preferably 45 to 50 °C, for 3 to 10, or preferably 4 to 5, hours.

Emulsifiers include water-soluble polymers or surfactants.

It may be advantageous to include some water-soluble polymer in the process in which the microcapsules are formed, as polyvinyl alcohol and some other polymers are known to be useful, for instance, as protective colloids or co-surfactants to enhance the stability of the oil-in- water emulsion. However, the amount of water-soluble polymer for this purpose should be kept relatively low, preferably about 5% by weight or less, more preferably no more than 2 to 3% by weight of the total formulation. Thus, if the amount of water-soluble polymer utilized is toward the lower end of the range of this invention, i.e., about 4-5% by weight, the water-soluble polymer may either be added to the suspension of microcapsules after the microcapsules have been formed, or may be initially added in the aqueous phase during the formation of the dispersion and the resulting microcapsules.

However, if the amount of water-soluble polymer utilized is toward the higher end (from about 5 to about 15% by weight) or is a more viscous material, it must be added to an already prepared suspension of microcapsules, and should not be present in the microcapsule production process, as it may be too viscous for a good emulsion to form or may interfere with the production of the capsule shell walls.

The water-soluble polymers usable in this invention include both synthetic and natural polymers such as polyvinylpyrrolidone, polyvinyl alcohol, polyethylene oxides,

ethylene/maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, water-soluble cellulose, water-soluble polyamides or polyesters, copolymers or

homopolymers of acrylic acids, water-soluble starches and modified starches, natural gums such as alginates, dextrins and proteins such as gelatins and caseins. A preferred water- soluble polymer comprises polyvinyl alcohol. Polyvinyl alcohols are obtained by hydrolysis of polyvinyl acetates and are usually sold in solid form, in a number of variations of molecular weight and degree of hydrolysis. In general, polyvinyl alcohol of lower molecular weight and/or lesser degree of hydrolysis tends to be more water-soluble. For instance, partially hydrolyzed polyvinyl alcohols (e.g., up to about 89-90% hydrolyzed) tend to be more water soluble and thus preferred for use in this invention. The solid polyvinyl alcohols are used in this invention by dissolving them in water to form solutions.

Alternatively or additionally surfactants (such as dispersants, protective colloids, emulsifiers, wetting agents) can be used to emulsify the water-immiscible components in the aqueous phase.

Suitable surfactants include nonionic and/or ionic substances, for example from the classes of the alcohol-POE and/or -POP ethers, acid and/or POP POE esters, alkylaryl and/or POP POE ethers, fat and/or POP POE adducts, POE- and/or POP-polyol derivatives, POE- and/or POP-sorbitan or -sugar adducts.

Suitable surfactants include the alkali metal salts, alkaline earth metal salts and ammonium salts of aromatic sulfonic acids, for example lignosulfonic acids (e.g. Borresperse types, Borregaard), phenolsulfonic acids, naphthalenesulfonic acids (Morwet types, Akzo Nobel) and dibutylnaphthalenesulfonic acid (Nekal types, BASF AG), and of fatty acids, alkyl, aryl or alkylaryl sulfonates, alkyl, aryl or alkylaryl sulfates, lauryl ether sulfates and fatty alcohol sulfates, and salts of sulfated hexa-, hepta- and octadecanols, and also of fatty alcohol glycol ethers, condensates of sulfonated naphthalene and its derivatives with formaldehyde, condensates of naphthalene or of the naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated isooctyl-, octyl- or nonylphenol, alkylphenyl or tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol/ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers or polyoxypropylene alkyl ethers, lauryl alcohol poly glycol ether acetate, sorbitol esters, alkyl or aryl phosphates or the corresponding PO-ether adducts, lignosulfate waste liquors and proteins, denaturated proteins, polysaccharides (e.g.

methylcellulose), hydrophobic ally modified starches, polycarboxylates (BASF AG, Sokalan types), polyalkoxylates, polyvinylamine (BASF AG, Lupamine types), polyethyleneimine (BASF AG, Lupasol types), polyvinylpyrrolidone and copolymers thereof and mixtures thereof. Notable surfactants include lignin sulfonates such as sodium lignosulfate, commercially available under the Reax^®, Polyfon^® or Kraftsperse^® tradenames.

In another embodiment, the formulation of the invention contains pore-forming material that would facilitate permeation of the herbicide out of the microcapsules.

Optionally the polymeric shell may be crosslinked by inclusion of additional monomers capable of reacting with the isocyanates such as amines or alcohols with three or more functional groups. Cross-linking may be accomplished by the inclusion of a cross-linker such as polyvinyl alcohol.

The microcapsules comprising pethoxamid typically have a diameter ranging from 0.1 micron to 500 microns. In some embodiments, the capsule suspension formulation comprises a plurality of microcapsules, wherein at least 90% of one population of microcapsules has an effective particle size ("D90") of less than about 500 microns; in another embodiment D90 is less than about 100 microns, and yet in another embodiment, D90 is up to or less than 20, 18, 15, or 10 microns. In a specific embodiment, the microcapsule population has a particle size defined by D90 of between about 1 and about 7 microns, preferably between 2-6 microns.

Furthermore, formulation process may include the addition and formulation by conventional techniques of safener(s), second herbicide(s), and one or more further auxiliaries customary for formulating crop protection agents so as to arrive at the herbicidal composition.

Products for preparing herbicidal compositions

The invention also provides a product for preparing a herbicidal composition, comprising in a first container a capsule suspension formulation of pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine, diethyl triamine, triethylenetetramine, 1,6 hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate; and comprising in a second container a composition comprising one or more safeners and/or one or more second herbicides.

The herbicidal compositions prepared from the product described herein typically have the characteristics of the herbicidal compositions of the invention and can

correspondingly be used in the methods of the invention, including each and every of the described embodiments thereof. Hence, reference is made to the detailed description herein of the section“Herbicidal compositions”,“Preparation of herbicidal compositions” and to “Methods for controlling weeds”.

Hence, the herbicidal composition may be presented as a product comprising two compositions which can be mixed, e.g. tank-mixed, to the ready-to-use herbicidal composition shortly before or immediately before use. Hence, the components of the product according to the invention can be used individually or already partially or completely mixed with one another to prepare the herbicidal composition according to the invention. It is also possible for them to be packaged as a kit of two compositions and used later in time such as by combining the composition to form a herbicidal composition for application, or by applying the compositions separately and sequentially to the same locus.

Hence, the product may comprise - in the first container - the capsule suspension formulation comprising pethoxamid including a liquid carrier and/or one or more surfactants; and - in the second container - a composition comprising the safener(s) and/or second herbicide(s) and a solid or liquid carrier and/or one or more surfactants.

Alternatively, the product may comprise - in the first container - the capsule suspension formulation comprising pethoxamid and one or more safeners and including a liquid carrier and/or one or more surfactants, for example such that pethoxamid and the safener(s) are encapsulated together; and - in the second container - a composition comprising the one or more second herbicides and a solid or liquid carrier and/or one or more surfactants.

Further alternatively, the product may comprise - in the first container - the capsule suspension formulation comprising pethoxamid and one or more second herbicides and including a liquid carrier and/or one or more surfactants for example such that pethoxamid and the second herbicide(s) are encapsulated together; and - in the second container - a composition comprising the one or more safeners and a solid or liquid carrier and/or one or more surfactants.

It should be understood that many variations are possibly for the products according to the invention, just as it is to be understood that the formulations/compositions may further comprise further auxiliaries customary for formulating crop protection agents, as described hereinabove for the herbicidal compositions.

In one embodiment of the invention, the product (kit) may include one or more, including all, components that may be used to prepare a subject herbicidal composition. For example, kits may include encapsulated pethoxamid and optionally one or more herbicide component(s) and/or a formulant component and/or a safener component. One or more of the components may already be combined together or pre-formulated. In those embodiments where more than two components are provided in a kit, the components may already be combined together and as such are packaged in a single container such as a vial, bottle, can, pouch, bag, or canister. In other embodiments, two or more components of a kit may be packaged separately, i.e. not pre-formulated. As such, kits may include one or more separate containers such as vials, cans, bottles, pouches, bags or canisters, each container containing a separate component for a herbicidal composition. In both forms, a component of the kit may be applied separately from or together with the further components or as a component of a combination according to the invention for preparing the herbicidal composition according to the invention.

Methods for controlling weeds

The invention also relates to a method of controlling plants, in particular weeds, which comprises applying to the plants or to the locus thereof a herbicidal composition as defined herein.“Locus” means the area in which the plants are growing or will grow.

In particular, the invention provides a method for controlling weeds comprising exposing the weeds to a herbicidally effective amount of herbicidal composition as defined herein, or of a herbicidal composition prepared from the product defined herein. The invention in particular relates to a method for the selective control of weeds in areas where useful plants like crops are growing or will grow.

Moreover, the invention provides a method for controlling undesired plant growth comprises applying to the locus where such control is desired a herbicidally effective amount of herbicidal composition as defined herein, or of a herbicidal composition prepared from the product defined herein.

The invention also relates to a method of inhibiting plant growth which comprises applying to the plants or to the locus thereof a herbicidal composition according to this invention.

As mentioned above, the methods according to the invention are particularly interesting where the weed or weeds to be controlled are present together with useful plants. Also, the herbicidal composition to be applied preferably comprises one or more safeners to reduce injury to useful plants, e.g. as described hereinabove for the herbicidal compositions according to the invention. Preferably, at least one safener (in particular all safeners) is selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof.

The rates of application of the compounds contained in the herbicidal composition vary within wide limits and depend on the nature of the soil (for instance, texture, organic matter etc.), the method of application (pre- or post-emergence; seed dressing; application to the seed furrow; no tillage application etc.), the crop plant, the weed to be controlled, the prevailing climatic conditions, and other factors governed by the method of application, the time of application and the target crop.

Useful plants in which the herbicidal composition according to the invention can be used include crops such as cereals (for example barley, wheat, corn (maize) or rice), cotton, oilseed rape, soybeans, sugar beet, and sugar cane. Crop plants can also include trees, such as fruit trees, palm trees, coconut trees or other nuts, vines such as grapes, fruit bushes, fruit plants and vegetables.

The method for controlling unwanted or undesired vegetation (weeds) comprises application of a composition as herein described, in particular where crop plants are cultivated, for example in crops of the following crop plants: Allium cepa, Ananas comosus, Arachis hypogaea, Asparagus officinalis, Avena sativa, Beta vulgaris spec altissima, Beta vulgaris spec rapa, Brassica napus var. napus, Brassica napus var. napobrassica, Brassica rapa var. silvestris, Brassica oleracea, Brassica nigra, Camellia sinensis, Carthamus tinctorius, Carya illinoinensis, Citrus limon, Citrus sinensis, Coffea arabica, Coffea canephora, Coffea liberica, Cucumis sativus, Cynodon dactylon, Daucus carota, Elaeis guineensis, Fragaria vesca, Glycine max, Gossypium hirsutum, Gossypium arboreum, Gossypium herbaceum, Gossypium vitifolium, Helianthus annuus, Hevea brasiliensis, Hordeum vulgare, Humulus lupulus, Ipomoea batatas, Juglans regia, Lens culinaris, Linum usitatissimum, Lycopersicon lycopersicum, Malus spec. , Manihot esculenta, Medicago sativa, Musa spec. , Nicotiana tabacum, Nicotiana rustica, Olea europaea, Oryza sativa, Phaseolus lunatus, Phaseolus vulgaris, Picea abies, Pinus spec., Pistacia vera, Pisum sativum, Prunus avium, Prunus persica, Pyrus communis, Prunus armeniaca, Prunus cerasus, Prunus dulcis and prunus domestica, Ribes sylvestre, Ricinus communis, Saccharum officinarum, Secale cereale, Sinapis alba, Solanum tuberosum, Sorghum bicolor (s. vulgare), Theobroma cacao, Trifolium pratense, Triticum aestivum, Triticale, Triticum durum, Viciafaba, Vitis vinifera, Zea mays, especially crops of cereals, com, soybeans, rice, oilseed rape, cotton, potatoes, peanuts, sunflower or permanent crops, and also in crops which are resistant to one or more herbicides or to attack by insects owing to genetic engineering or breeding.

In addition, the herbicidal compositions according to the invention may also be used in crops which tolerate the action of herbicides owing to breeding, including genetic engineering methods. The herbicidal compositions according to the invention can also be used in crops which tolerate insects or fungal attack as the result of breeding, including genetic engineering methods.

The application is generally made by spraying the herbicidal composition, typically by tractor mounted sprayer for large areas, but other methods such as drip or drench can also be used. The user may also apply the herbicidal composition according to the invention usually from a pre-dosage device, a backpack sprayer, a spray tank, or a spray plane. Here, the herbicidal composition is made up with water and/or buffer to the desired application concentration, it being possible, if appropriate, to add further auxiliaries, and the ready-to-use spray liquor or the herbicidal composition according to the invention is thus obtained.

Usually, 100 to 1000 liters of the ready-to-use spray liquor are applied per hectare of agricultural useful area, preferably 200 to 500 liters.

When used with a safener or safeners, and/or with one or more second herbicides, the pethoxamid and the safener(s) and/or second herbicides can be applied jointly or separately, simultaneously or in succession, before, during or after the emergence of the plants i.e. both the useful plants and/or weeds. In any event, pethoxamid is presented in a herbicidal composition as defined herein, whereas the safener(s) may be present in the herbicidal composition together with pethoxamid, or may be present in a separate composition.

Likewise, any second herbicide(s) may be present in the herbicidal composition together with pethoxamid, or may be present in a separate herbicidal composition. The order of the application of pethoxamid and the safener is of minor importance. The only thing that is important is that pethoxamid and the safener are present simultaneously at the site of action, i.e. are at the same time in contact with or taken up by the useful plant to be controlled. Notably, when the pethoxamid and the safener are included in the same composition or tank mix, they are applied jointly and simultaneously. The required application rate of active compound composition, i.e. pethoxamid and the safener(s), depends on the composition of the plant stand, on the development stage of the plants, on the climatic conditions at the site of use and on the application technique. In general, the combined application rate of pethoxamid and the safener(s) is in the range of 0.05 to 5 kg/ha, or in the range of 0.05 to 3 kg/ha, preferably 0.06 to 3 kg/ha, and in particular 0.1 to 2.5 kg/ha, of active ingredients.

The required application rates of pethoxamid are generally in the range of 0.05 to 5 kg/ha, or 0.05 to 2.5 kg/ha, and preferably 0.1 to 2.5 kg/ha, of active ingredient (a.L).

The required application rates of safener, e.g. benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl or a combination thereof, are generally in the range of 0.001 to 1 kg/ha, or 0.001 to 0.5 kg/ha, preferably 0.005 to 0.3 kg/ha, and in particular 0.01 to 0.1 kg/ha.

Also, pethoxamid and the safener(s), if present, are typically applied in a weight ratio (pethoxamid:safener(s)) of in the range of 1:1 to 500:1, preferably 1:1 to 250:1, in particular 1:1 to 150:1, particularly preferably 1:1 to 100: 1, more preferably 2:1 to 70: 1; even more preferably 10:1 to 70:1 and most preferably 10:1 to 40: 1, depending on the safener used.

The herbicidal compositions are applied to the plants mainly by spraying the leaves of the plant or the locus of the plant, such as the soil surrounding the plant. Here, the application can be carried out using, for example, water as a carrier by customary spraying techniques using spray liquor amounts of from about 100 to 1000 L/ha (for example from 300 to 400 L/ha). The herbicidal compositions may also be applied by the low- volume or the ultra-low- volume method.

The herbicidal composition comprising pethoxamid and safener can be applied pre-, early post, or post-emergence. The safener and agriculturally acceptable derivatives thereof are recommended to be applied post-emergence of the weeds to provide a herbicidal effect and pethoxamid recommended for pre-emergence of the weeds. This is advantageous since it broadens the time where the combination effectively controls emerging weeds. In a preferred embodiment, the herbicidal compositions are applied early post-emergence.

EXAMPLES

The formulations of the invention were prepared by the methods exemplified in the following Examples. Example 1

A microcapsule suspension was prepared using the materials summarized in Table 1 according to the general procedure below.

TABLE 1

Amount

Material Description Function (g)

Pethoxamid Technical material* Active ingredient 255 polymethylene polyphenylisocyanate

Encapsulation

PAPI^® 2027 (Dow) containing 4,4’ -methylene diphenyl

agent

diisocyanate

Encapsulation

HMDA 43% Hexamethylene diamine in water

agent

Solvesso™ Aromatic a mixture of C₉-C₁₅ aromatic, naphthalene- solvent 45 200ND (ExxonMobil) depleted hydrocarbons, flash-point 200 °C

water solvent 250

Celvol^® 24-203 24% by weight of polyvinyl alcohol

surfactant 35 (Celanese) (88% hydrolyzed) in water

Agnique^® NSC 3N wetting and

Naphthalene sulfonate condensate

(BASF) dispersing agent

TX 1520 (Dow Coming) 20% silicone emulsion antifoam agent 4 aqueous solution of 1, 2-benzisothiazolin-3

Proxel^® GXL (Lonza) microbiostat 0.2

one

Urea antifreeze 45

# At least 94% pure (less than 6% impurities).

In a one-liter stainless steel beaker were placed the aqueous 24% polyvinyl alcohol solution (Celvol^® 24-203), antifoam agent and naphthalene sulfonate formaldehyde condensate and 250.0 grams of water. After this mixture was mixed for 10 seconds at low speed in a high-shear mixer, a pre-blended solution of pethoxamid, PAPI^® 2027, and petroleum solvent (Aromatic 200 ND) was added, and the mixture was emulsified in the high shear mixer for 10 to 20 seconds. The shear rate was reduced and the aqueous solution of HMDA was added in a steady stream. After addition was complete, the mixture was then placed in a one-liter jacketed resin flask with the jacket pre-heated to 50 °C. The mixture was stirred at a moderate speed with an air-powered stirrer. The mixture was then stirred at 50 °C for four hours. After this time, urea and the microbiostat preservative were added after the microencapsulation process was complete to provide a stable matrix for the composition. Optionally, xanthan gum may also be added to adjust the viscosity. The formulation was then stirred for about one hour and stored for later use. Examples 2-3

Additional Examples were prepared as summarized in Table 2.

Table 2

Example 2 3

Material Amount (g)

Pethoxamid 255 280

PAPI^® 2027 20 40

HMDA 20 40

Solvesso™ Aromatic 200ND 45 45

water 228 250

Reax^® 88B 8 8

Celvol^® 24-203 0 8

NaNOs 37 0

CaCb 37 0

Urea 0 45

Example 2 was prepared as described in the following. In a one-liter stainless steel beaker were placed Reax^® 88B (sodium lignosulfonate) and 228.0 grams of water. After this mixture was mixed for 10-20 seconds at low speed in a high-shear mixer, a pre-blended solution of pethoxamid, PAPI^® 2027, and petroleum solvent (Aromatic 200 ND) was added, and the mixture was emulsified in the high shear mixer for 10-20 seconds. After a homogeneous emulsion was obtained, the shear rate was reduced and HMDA was added in a steady stream. Mixing was continued for approximately 1 minute and the mixture was then transferred to a one-liter jacketed resin flask with the jacket pre-heated to 50 °C. The mixture was stirred at a moderate speed (250-350 rpm) at 50 °C for four hours with an air-powered stirrer. The mixture was then stirred at 50 °C for four hours. Antifreeze materials, sodium nitrate and calcium chloride, were added after curing was complete. The formulation was then stirred for about one hour and stored for later use. Xanthan gum, a preservative and a pH adjuster can optionally be added to stabilize the mixture if required.

Example 3 was prepared similarly to Example 1.

Examples 4-5

Examples 4 and 5 include either benoxacor or dichlormid as safeners and are summarized in Table 3. Table 3

Example 4 5

Material Amount (g)

Pethoxamid 235 235

Benoxacor 7 0

Dichlormid 0 20

PAPI^® 2027 16 16

HMDA 16 16

Solvesso™ Aromatic 100ND 45 45

water 233 233

Celvol^® 24-203 8 8

Reax^® 88B 7.35 7.35

NaNOs 67 67

Example 4 was prepared according to the following procedure. Example 5 was prepared as in Example 4, except dichlormid was used instead of benoxacor.

In a one-liter stainless steel beaker were placed the aqueous 24% polyvinyl alcohol solution (Celvol^® 24-203), sodium lignosulfonate and 233.0 grams of water. After this mixture was mixed for 10 seconds at low speed in a high-shear mixer, a pre-blended solution of pethoxamid, benoxacor, PAPI^® 2027, and petroleum solvent (Aromatic 100 ND) was added, and the mixture was emulsified in the high shear mixer for 10-20 seconds. The shear rate was reduced and the aqueous solution of HMDA added in a steady stream. After addition was complete, the mixture was then placed in a one-liter jacketed resin flask with the jacket pre-heated to 50 °C. The mixture was stirred at a moderate speed with an air-powered stirrer. The mixture was then stirred at 50 °C for four hours. After curing was complete, sodium nitrate was added to the mixture and allowed to dissolve completely. The formulation was then stirred for about one hour and stored for later use. Optionally xanthan gum and a preservative were added after the microencapsulation process was complete to provide a stable matrix for the composition.

Capsule suspensions comprising isoxadifen or isoxadifen-ethyl coencapsulated with pethoxamid can be prepared similarly.

Examples of capsule suspensions of pethoxamid plus a second herbicide such as clomazone, 2-(2,4-dichlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone, mesotrione, tembotrione or napropamide may be prepared similarly. For example, a mixture of

pethoxamid and the selected second herbicide, PAPI^® 2027, and solvent (such as Aromatic 200 ND) is preblended, then added to a mixture of water, surfactant and polyvinyl alcohol. The mixture is emulsified in the high shear mixer for a brief period, such as 10-20 seconds. The shear rate is reduced and an aqueous solution of HMDA is added in a steady stream. After addition is complete, the mixture is then placed in a one-liter jacketed resin flask with the jacket pre -heated to 50 °C. The mixture is stirred at a moderate speed with an air-powered stirrer until curing is complete, for example for four hours. After curing is complete, additional formulant(s) may be added such as an antifreeze component, xanthan gum and/or a preservative to the mixture. The formulation is then stirred for about one hour and stored for later use.

Comparative Example Cl is a 60% emulsifiable concentrate of pethoxamid, available commercially under the tradename Successor^®. Comparative Example C2 is an emulsifiable concentrate of 82.4% of S-metolachlor blended with benoxacor, available commercially under the tradename Dual II Magnum^®.

The compositions of the Examples were tested for storage stability at temperatures of -10 °C, +40 °C and +50 °C for up to twelve weeks and demonstrated good thermal stability in those tests. In particular, when the capsule suspensions were treated under cold conditions, the microcapsules stayed in suspension and could be easily reconstituted by gentle shaking.

Weed control and injury to crop plants were assessed by visually estimating the control, as a percentage, relative to the weed species in the untreated controls in a greenhouse setting. The weed control evaluation is made at 14 and 21 days after treatment, as summarized in Table 4.

Table 4

Inspection of the data summarized in Table 6 shows that an emulsifiable concentrate of pethoxamid (Comparative Example Cl) had significant phytotoxicity on corn at rates that provided good control of red rice and redroot pigweed. The capsule suspension formulations, Examples 1, 2, and 3, provided reduced phytotoxicity on com while maintaining good herbicidal activity on red rice and redroot pigweed compared to Cl. Comparative Example C2 is an emulsifiable concentrate containing S-metolachlor safened with benoxacor, which provided excellent weed control with low phytotoxicity on corn at 560 and 1120 g a.i./ha. Example 4 provided very similar levels of phytotoxicity and weed control compared to C2. Example 5 provided somewhat higher levels of phytotoxicity but similar weed control compared to C2.

It is understood that there may be variations from the specific embodiments described herein without departing from the spirit or concept of the present invention as defined in the claims. Included in such variations are mixtures in which the encapsulated pethoxamid of this invention is part of a mixture with one or more other herbicides, whether or not encapsulated.

Claims

1. A herbicidal composition comprising a capsule suspension formulation of pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine, diethyltriamine, triethylenetetramine, l,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate.

2. The herbicidal composition according to claim 1 , wherein the composition further comprises one or more safeners.

3. The herbicidal composition according to claim 2, wherein at least one safener is selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof.

4. The herbicidal composition according to any one of the claims 2 to 3 formulated as a capsule suspension composition comprising pethoxamid and one or more safeners encapsulated together, and at least one liquid carrier and/or one or more surfactants.

5. The herbicidal composition according to any one of the claims 1 to 4, wherein the polymeric isocyanate comprises polymethylenepolyphenylene isocyanate and/or

polymethylene polyphenyl isocyanate containing 4,4'-methylene bisphenyl isocyanate.

6. The herbicidal composition according to any one of the claims 1 to 5, wherein at least one amine is l,6-hexanediamine.

7. The herbicidal composition according to any one of the claims 1 to 6, wherein the polyurea is prepared from l,6-hexanediamine and polymethylene polyphenyl isocyanate containing 4,4'-methylene bisphenyl isocyanate.

8. A product for preparing a herbicidal composition, comprising in a first container a capsule suspension formulation of pethoxamid, wherein pethoxamid is encapsulated in a shell of polyurea prepared from one or more amines selected from ethylenediamine,

diethyltriamine, triethylenetetramine, l,6-hexanediamine, and mixtures thereof, and a polymeric isocyanate in the absence of toluene diisocyanate; and comprising in a second container a composition comprising one or more safeners and/or one or more second herbicides.

9. The product according to claim 8, wherein one or more safeners and/or one or more second herbicides include at least one safener.

10. A method for controlling weeds comprising exposing the weeds to a herbicidally effective amount of the herbicidal composition defined in any one of the claims 1 to 7, or of a herbicidal composition prepared from the product defined in any one of the claims 8 to 9.

11. The method according to claim 10, wherein the weeds are present together with useful plants.

12. The method according to any one of the claims 10 to 11, wherein the herbicidal composition comprises one or more safeners to reduce injury to useful plants.

13. The method according to claim 12, wherein at least one safener is selected from benoxacor, dichlormid, isoxadifen, isoxadifen-ethyl, and combinations thereof.

14. The method according to any one of the claims 10 to 13, wherein the useful plants are selected from cereals, cotton, oilseed rape, soybeans, sugar beet, and sugar cane.

15. The method according to any one of the claims 10 to 14, wherein a combined application rate of pethoxamid and safener(s) is in the range of 0.05 to 3 kg/ha, or wherein the application rate of pethoxamid is in the range of 0.05 to 2.5 kg/ha, and the application rate of safener(s) is in the range of 0.001 to 1 kg/ha, or wherein pethoxamid and the safener(s) are applied in a weight ratio of in the range of 1 : 1 to 500: 1.