sign in sign up
<<
Home , Clomazone, Prometon

USOO9049866B2

(12) United States Patent (10) Patent No.: US 9,049,866 B2 Refardt et al. (45) Date of Patent: Jun. 9, 2015

(54) SYNERGISTIC HERBICIDAL COMBINATION (58) Field of Classification Search OF AND PETHOXAMD CPC ... A01N 43/80: A01N37/20: A01N 2300/00 USPC ...... 504/138, 140,271, 342, 111 (75) Inventors: Matthias Refardt, Ettingen (CH): See application file for complete search history. Casper Reinhard Christensen, Holstebro (DK) (56) References Cited (73) Assignee: CHEMINOVA A/S, Lemvig (DK) U.S. PATENT DOCUMENTS 4,405.357 A 9/1983 Chang (*) Notice: Subject to any disclaimer, the term of this 4,895,587 A * 1/1990 Kato et al...... 504,289 patent is extended or adjusted under 35 5,583,090 A 12/1996 Stern et al. U.S.C. 154(b) by 392 days. 5,597,780 A 1/1997 Lee et al. 2003, OO69137 A1 4/2003 Almsick et al. (21) Appl. No.: 12/991,499 FOREIGN PATENT DOCUMENTS (22) PCT Filed: May 7, 2009 EP O 206251 12, 1986 (86). PCT No.: PCT/DK2O09/OOO 105 WO WO 2009115433 A2 * 9, 2009 S371 (c)(1), OTHER PUBLICATIONS (2), (4) Date: Nov. 11, 2010 Colby, S.R., "Calculating Synergistic and Antagonistic Responses of Combinations'. Weed Science Society of America, vol. 15. (87) PCT Pub. No.: WO2009/135492 No. 1. (Jan. 1967), pp. 20-22. PCT Pub. Date: Nov. 12, 2009 * cited by examiner (65) Prior Publication Data Primary Examiner — John Pak US 2011 FOO59849 A1 Mar. 10, 2011 Assistant Examiner — Andriae M Holt (30) Foreign Application Priority Data (74) Attorney, Agent, or Firm — Leydig, Voit & Mayer, Ltd. May 9, 2008 (DK) ...... 2008 OO667 (57) ABSTRACT Presented are herbicidal compositions comprising as active (51) Int. Cl. ingredients clomaZone and pethoxamid. The combinations of AOIN 43/80 (2006.01) these herbicidal active compounds show a synergistic effect AOIN37/20 (2006.01) in the control of harmful plants. (52) U.S. Cl. CPC ...... A0IN 43/80 (2013.01) 19 Claims, No Drawings US 9,049,866 B2 1. 2 SYNERGISTC HERBICIDAL COMBINATION harmful plants are exposed to an effective amount of a syn OF CLOMAZONE AND PETHOXAMD ergistic combination of the compound A and the compound B. The present invention relates to herbicidal compositions In yet another embodiment, the invention relates to a her comprising as active ingredients the compound A which is bicidal composition comprising a herbicidal effective amount clomazone and the compound B which is pethoxamid. The of the compound A which is clomaZone and the compound B combinations of these active compounds show a synergistic which is pethoxamid. In a preferred embodiment the herbi effect in the control of harmful plants. The invention further cidal composition comprise a herbicidal effective amount of relates to a method for the control of harmful plants, such as the compound A and the compound B wherein the active weeds in crops of useful plants, and to the use of the herbicidal 10 components A and B are present in a synergistically effective compositions for that purpose. amount. The composition is preferably selected among those compositions comprising a form selected from the group BACKGROUND consisting of ready-to-use solutions, emulsifiable concen trates, emulsions, Suspensions, wettable powders, soluble The herbicidal active compound clomazone is known from 15 powders, granules, soluble granules, dispersible granules, U.S. Pat. No. 4,405.357 and is generally used to control microemulsions, microcapsule Suspensions and mixtures weeds in various crops. The herbicidal active compound thereof. pethoxamid is known from European patent application no. In a further embodiment, the invention relates to a method EP 206251-A1 and is generally used to control weeds in of reducing the Volatility of clomaZone, said method compris various crops such as control of grass weeds and broad-leaved ing combining clomaZone as compound A with a compound weeds. B which is pethoxamid, preferably in a herbicidal composi ClomaZone is known to be a very volatile organic com tion as described herein. Preferably the ratio between the pound to an extend so that clomaZone applied in a target area compounds A and B is in a ratio as to reduce the volatility of may move to adjacent areas and there cause discoloration, clomaZone on a comparative scale to an emulsifiable concen most typically whitening or some degree of bleaching, of a 25 trate composition comprising a similar amount of clomaZone variety of crops, trees, or decorative plants. While this bleach and without the compound B being present. Preferable com ing may be temporary when plants are exposed to Sufficiently pounds A and B are present in a herbicidal effective amount low concentrations, it is undesirable even when not causing but the compound B need not necessarily be present so as to the destruction of the affected plant. Accordingly appropriate produce a synergistic effect with the compound A. However, use instructions for clomaZone is often found on product 30 in a very preferred embodiment, the method of reducing the labels of commercially available clomaZone products and in Volatility of clomaZone comprise combining clomaZone as particular on emulsifiable concentrates formulations com compound A with a compound B which is pethoxamid, in a prising clomaZone in order to prevent exposure to clomaZone ratio as to reduce the volatility of the clomazone while main sensitive plants. Methods of reducing the volatility of cloma taining a synergistic herbicidal effect and without Substan Zone, i.e. to prevent or reduce vapor transfer of clomaZone to 35 tially sacrificing the overall herbicidal activity. Such ratios are plants which are not target of application, are proposed in preferably as herein described. Thus, the present invention U.S. Pat. Nos. 5,597,780 and 5,583,090 in which encapsula relates to a herbicidal composition having reduced cloma tion techniques are applied as to prepare microcapsule Sus Zone vapour transfer comprising a compound A which is pension formulations of clomaZone. clomaZone and a compound B which is pethoxamid and pref In crop protection products, it is always desirable to 40 erably the composition comprise a herbicidal effective increase the specific activity of an active ingredient and the amount of the compound A and the compound B wherein the reliability of action. It is an object of the present invention to active components A and B are present in a synergistically provide mixtures which comprise a compound A which is effective amount. Such ratios and amounts are preferably as clomaZone, and the compound B which is pethoxamid which herein described. are selective in crops to control undesirable harmful plants. 45 The compositions according to the invention can be Surprisingly, it has now been found that combinations of employed for the selective control of grasses and annual and these active compounds exhibits a synergistic effect when perennial monocotyledonous and dicotyledonous harmful used for the control of harmful plants. Further it has been plants the presence of useful plants such as maize, soya, peas, found that by combining clomaZone with pethoxamid the beans, Sunflowers, oilseed rape, Sugar cane, cassava, pump Volatile nature of clomaZone is significantly reduced. 50 kins, potatoes, vegetables and tobacco. Within the scope of this invention is also the control of such harmful plants found DESCRIPTION OF THE INVENTION among transgenic useful plants or among useful plants selected by classical means which are resistant to the active In one embodiment, the invention relates to a method for compounds A and B. Likewise, the compositions can be controlling harmful plants comprising exposing said harmful 55 employed for controlling undesirable harmful plants in plan plants to an effective amount of a combination of the com tation crops. Among harmful plants, e.g. weeds or Volunteer pound A which is clomaZone, and the compound B which is crop plants, that may be controlled are Ambrosia artemisiifo pethoxamid. In a preferred embodiment the harmful plants lia, Amaranthus retroflexus, Apera spica-venti, Capsella are exposed to an effective amount of a synergistic combina bursa-pastoris, Chenopodium album, Convolvulus arvensis, tion of the compound A and the compound B. 60 Digitaria ischaemum, Digitaria sanguinalis, Echinochloa In another embodiment, the invention relates to a method crus-galli, Galium aparine, Lamium purpureum, Matricaria for controlling harmful plants in the presence of useful plants spp., Mercurialis annua, Myosotis arvensis, Poa spp., comprising exposing said harmful plants and useful plants to Polygonum convolvulus, Polygonum persicaria, Portulaca an effective amount of a combination of the compound A oleracea, Senecio vulgaris, Setaria geniculata, Solanum which is clomaZone, and the compound B which is pethoxa 65 nigrum, Stellaria media, Veronica persica and Viola arvensis. mid, it being understood that the useful plants remain Compositions containing the active compounds A and B unharmed after the exposure. In a preferred embodiment the may be employed in any conventional form, for example, in US 9,049,866 B2 3 4 the form of a twin pack, or ready-to-use Solutions, emulsifi essential. Likewise, any form of combination of the active able concentrates, emulsions, Suspensions, wettable powders, components may be applied for either pre- or post-emergence soluble powders, granules, soluble granules, dispersible control of harmful plants, e.g. weeds in crops of useful plants. granules, microemulsions, microcapsule Suspensions e.g. Rates of application of the composition will vary according capsules comprising both active ingredients or present within 5 to prevailing conditions such as targeted weeds, degree of separate capsules; and mixtures thereof Such as a ZC, ZE or infestation, weather conditions, Soil conditions, crop species, ZW formulation. Such compositions can beformulated using mode of application, and application time. Compositions adjuvants and formulation techniques that are known in the containing the active compounds may be applied in the man art for individually formulating the . For example, ner, which they are formulated, as discussed above. For the herbicides may be mixed together, optionally with other 10 example, they may be applied as sprays, such as water-dis formulating ingredients. persible concentrates, wettable powders, or water-dispersible The compositions may contain a diluent, which may be granules. added during the formulation process, after the formulation The weight ratio of component A to component B is pref process (e.g. by the user—a farmer or custom applicator), or erably selected to provide a synergistic herbicidal action. both. The term diluent includes all liquid and solid agricul 15 Such amounts are also called synergistically effective turally acceptable material-including carriers which may be amounts and can easily be determined by the skilled person added to the herbicides to bring them in a suitable application using well known principles. In general, the weight ratio of or commercial form and include solvents, emulsifiers, and A:B ranges from about 1:1 to about 1:30, preferably 1:5 to dispersants. Examples of suitable solid diluents or carriers are 1:25 and more preferably 1:8 to 1:20 and most preferably 1:10 aluminum silicate, talc, calcined magnesia, kieselguhr, trical to 1:15. The weight ratio of A:B will depend on various cium phosphate, powdered cork, absorbent carbon black, factors such as the mode of application, the harmful plants to chalk, silica, and clays such as kaolin and bentonite. be combated, the useful plant to be protected, the application Examples of Suitable liquid diluents include water, organic time, etc. Solvents (e.g. acetophenone, cyclohexanone, isophorone, An effective amount of A and B is any amount that has the toluene, Xylene, petroleum distillates), amines (e.g. ethano 25 ability to combat the harmful plants. In general, satisfactory lamine, dimethylformamide), and mineral, animal, and Veg results will be obtained when employing from about 1 to etable oils (used alone or in combination). The compositions about 300 g/ha, preferably 10 to about 200 g/ha of compound may also contain Surfactants, protective colloids, thickeners, A, and more preferably from about 50 to about 150 g/ha; and penetrating agents, stabilizers, sequestering agents, anti-cak from about 100 to about 3000 g/ha, preferably about 500 to ing agents, coloring agents, corrosion inhibitors, and dispers 30 about 2500 g/ha of the compound B, and more preferably ants such as lignoSulfite waste liquors and methylcellulose. from about 800 to about 1500 g/ha. However, higher and in The term surfactant, as used herein, means an agriculturally particular lower doses may also provide adequate control. acceptable material which imparts emulsifiability, stability, Additional herbicides may be also be used, preferably so spreading, wetting, dispersibility or other Surface-modifying provided that the additional herbicide does not interfere with properties. Examples of Suitable Surfactants include lignin 35 the synergistic relationship between the compound A herbi Sulfonates, fatty acid Sulfonates (e.g. lauryl Sulfonate), the cide and the compound B. An additional herbicide may be condensation product of formaldehyde with naphthalene sul utilized if broadening of the spectrum of control or preventing fonate, alkylarylsulfonates, ethoxylated alkylphenols, and the build-up of resistance is desired. ethoxylated fatty alcohols. Other known surfactants that have Examples of additional herbicides are acetyl-CoA car been used with herbicides are also acceptable. 40 boxylase inhibitors (ACC), for example cyclohexenone When mixed with additional components, the composition Oxime ethers, such as alloxydim, clethodim, cloproxydim, typically contain about 0.01 to about 95% by weight of active cycloxydim, , tralkoxydim, butroxydim, clefoxy compounds, about 0 to about 20% agriculturally acceptable dim or tepraloxydim; phenoxyphenoxypropionic esters. Such surfactants, and about 5 to 99.99% solid or liquid diluent(s). as clodinafop-propargyl, cyhalofopbutyl, diclofop-methyl, The compositions may additionally contain other additives 45 fenoxaprop-ethyl, fenoxaprop-P-ethyl, fenthiapropethyl, flu known in the art, such as pigments, thickeners and the like. azifop-butyl, -P-butyl, haloxyfop-ethoxyethyl, The compositions may be applied in various combinations haloxyflopmethyl, haloxyfop-P-methyl, isoxapyrifop, pro of the two active compounds. For example, they may be paquizafop, quizalofop-ethyl, quizalofop-P-ethyl or quizalo applied as a single “ready-mix' form, or in a combined spray fop-tefuryl; or arylaminopropionic acids, such as flamprop mixture composed from separate formulations of the active 50 methyl or flamprop-isopropyl; p-hydroxyphenylpyruvat compounds, e.g. a "tank-mix' form. Thus, to be used in dioxygenase (HPPD)-inhibitors, for example pyrazolynate, combination, it is not necessary that the two herbicides, be pyrazoxyfen, benzofenap, Sulcotrione, isoxaflutole, mesotri applied in a physically combined form, or even at the same one, isoxachlortole, ketospiradox, tembotrione; acetolactate time, i.e. the components may be applied in a separately synthase inhibitors (ALS), for example imidazolinones, such and/or sequentially application, provided that the application 55 as , imazaquin, imazamethabenz-methyl of the second active compound occurs within a reasonable (imazame), imaZamox, or imazethapyr; pyrimidyl period of time from the application of the first active com ethers, such as pyrithiobac-acid, pyrithiobac-Sodium, bispy pound. The combination effect results so long as the two ribac-Sodium or pyribenzoxym: Sulfonamides, such as clo herbicides are present at the same time, regardless of when ranSulam, dicloSulam, florasulam, flumetSulam, metoSulam they were applied. Thus, for instance, a physical combination 60 or penoXSulam; or Sulfonylureas, such as amidosulfuron, of the two herbicides could be applied, or one could be azimsulfuron, bensulfuron-methyl, chlorimuronethyl, chlor applied earlier than the other so long as the earlier-applied Sulfuron, cinosulfuron, cyclosulfamuron, ethametSulfuron herbicide is still present on the harmful plant to be controlled methyl, ethoxysulfuron, , foramsulfuron, halo or in the soil surrounding the harmful plant to be controlled Sulfuron-methyl, imaZosulfuron, iodosulfuron, metSulfuron when the second is applied, and so long as the weight ratio of 65 methyl, nicosulfuron, primisulfuron-methyl, prosulfuron, available herbicides falls within that provided herein. The pyrazosulfuronethyl, rimsulfuron, Sulfometuron-methyl or order of applying the individual components A and B is not -3-oxetanyl, sulfosulfuron, thifensulfuron-methyl, triasulfu US 9,049,866 B2 5 6 ron, tribenuron-methyl, triflusulfuron-methyl or tritosulfu dipropetryn, dymron, eglinazin-ethyl, , ethiozin, ron; amides, for example allidochlor, benzoylprop-ethyl, bro flucabazone, fluorbentranil, flupoxam, isocarbamid, isopro mobutide, chlorthiamid, diphenamid, etobenzanid palin, karbutilate, mefluidide, monuron, napropamide, (benzchlomet), fluthiamide, fosamin or monalide; auxinher napropanilide, nitralin, oxaciclomefone, phenisopham, pip bicides, for example pyridinecarboxylic acids, such as clopy erophos, procyazine, profluralin, pyributicarb, secbumeton, ralid or : 2,4-D or benazolin; transport inhibi sulfallate (CDEC), terbucarb, triaziflam, triazofenamid or tri tors, for example naptalame or diflufenZopyr; carotenoid meturon; or their environmentally compatible salts, “acids”. biosynthesis inhibitors, for example amitrol, diflufenican, esters and amides. fluorochloridone, fluridone, flurtamone, norflurazon or The compounds A and B and optionally one or more addi picolinafen; enolpyruvylshikimate-3-phosphate synthase 10 inhibitors (EPSPS), for example or sulfosate: tional herbicides may also be applied in combination with at glutamine synthetase inhibitors, for example bilanafos (biala least one Safener compound. A safener compound is a com phos) or -ammonium; lipid biosynthesis inhibi pound, which is effective for antagonism the herbicides A, B tors, for example anilides, such as anilofos or mefenacet; or both or the optional additional herbicide(s), and which is chloroacetanilides, such as , S-dimethenamid, 15 applied in a Suitable amount i.e., an amount which counter , , , butenachlor, diethatyl-ethyl, acts to some degree a phytotoxic response of a useful plant to dimethachlor, metaZachlor, , Smetolachlor, preti the herbicide(s). The safener may suitably be incorporated in lachior, , prynachlor, terbuchlor, thenylchlor or the composition discussed above. Safeners suitable for use Xylachlor; thioureas. Such as butylate, cycloate, di-allate, include cloquintocet, cloquintocet-mexyl, benoxacor, dichlo dimepiperate, EPTC, esprocarb, molinate, pebulate, prosul rmid, fenchlorazole-ethyl, fenclorim, flurazole, fluxofenim, focarb, thiobencarb (benthiocarb), tri-allate or vernolate; or furilazole, isoxadifen, isoxadifen-ethyl, mefenpyr, mefen benfuresate or perfluidone; mitosis inhibitors, for example pyrdiethyl and oxabetrinil or their environmentally compat carbamates, such as , carbetamid, chlorpropham, ible salts, “acids, esters and amides. orbencarb, propyZamid, propham or tiocarbazil; dinitroa A synergistic effect exists whenever the action of a com nilines, such as benefin, butralin, dinitramin, ethalfluralin, 25 bination of active components is greater than the sum of the fluchloralin, oryzalin, , prodiamine or triflura action of each of the components alone. Therefore, a syner lin; , such as or thiazopyr; or butamifos, gistic combination is a combination of active components chlorthal-dimethyl (DCPA) or maleic hydrazide; protopor having an action that is greater than the Sum of the action of phyrinogen IX oxidase inhibitors, for example diphenyl each active component alone, and a synergistically effective ethers, such as , acifluorfen-Sodium, , 30 , chlornitrofen (CNP), ethoxyfen, fluorodifen, fluoro amount is an effective amount of a synergistic combination. glycofen-ethyl, , furyloxyfen, , , Well-known methods for determining whether synergy exists nitrofluorfenor oxyfluorfen: oxadiazoles, such as oxadiargyl include the Colby method, the Tammes method and the Wad or oxadiaZon; cyclic imides, such as azafenidin, , ley method, all of which are described below. Any one of carfentraZone-ethyl, cinidon-ethyl, flumiclorac-pentyl, flu 35 these methods may be used to determine if synergy exists mioxazin, flumipropyn, flupropacil, fluthiacet-methyl, between the compounds A and B. or thidiazimin; or pyrazoles, such as ET-751, In the Colby method, also referred to as the Limpels JV 485 or nipyraclofen; photosynthesis inhibitors, for method, the action to be expected E for a given active ingre example , pyridate or pyridafol; benzothiadiazino dient combination obeys the so-called Colby formula. nes, such as bentaZone; dinitrophenols, for example bro 40 According to Colby, the expected action of active ingredients mofenoxim, , dinoseb-acetate, dinoterb or DNOC: A+Busing p--q ppm of active ingredient is: dipyridylenes, such as cyperquat-chloride, difenZoquat-me thylsulfate, diguat or -dichloride; , such as chlorbromuron, chlorotoluron, difenoXuron, dimefuron, diu ron, ethidimuron, fenuron, fluometuron, isoproturon, isou 45 ron, , methabenzthiaZuron, , metobenzu ron, metoxuron, , neburon, siduron or where ppm milligrams of active ingredient (a.i.) per liter of ; phenols, such as or ioxynil; chlo spray mixture X=% action by component A using p ppm of ridazon; triazines. Such as ametryn, , , des active ingredientY=% action by component Busing q ppm of metryn, dimethamethryn, , , prometryn, 50 propazine, , Simetryn, terbumeton, terbutryn, terbu active ingredient. If the ratio R defined as the action actually tylazine or trietazine; triazinones, such as metamitron or observed (O) divided by the expected action (E) is >1 then the , uracils, such as bromacil, lenacil or terbacil; or action of the combination is Superadditive, i.e. there is a biscarbamates, such as desmedipham or phenmedipham; synergistic effect. For a more detailed description of the growth Substances, for example aryloxyalkanoic acids. Such 55 Colby formula, see Colby, S. R. “Calculating synergistic and as 2,4-DB, clomeprop, , dichlorprop-P (2,4-DP antagonistic responses of herbicide combination. Weeds, P), fluoroxypyr, MCPA, MCPB, , mecoprop-P or Vol. 15, pages 20-22; 1967; see also Limpel et al., Proc. ; benzoic acids, such as or ; or NEWCC 16:48-53 (1962). quinolinecarboxylic acids, such as or quinmerac: The Tammes method uses a graphic representation to cell wall synthesis inhibitors, for example isoxaben or 60 determine whether a synergistic effect exists. See “Isoboles, a dichiobenil; various other herbicides, for example dichloro graphic representation of synergism in pesticides. Nether propionic acids. Such as dalapon; dihydrobenzofurans. Such lands Journal of Plant Pathology, 70 (1964) p. 73-80. as ethofumesate; henylacetic acids, such as chlorfenac The Wadley method is based on comparison of an observed (fenac); oraZiprotryn, barban, , benzthiaZuron, ben EC50 value (i.e concentration providing 50% control) Zofluor, buminafos, buthidazole, buturon, cafenstrole, chlor 65 obtained from experimental data using the dose response bufam, chlorfemprop-methyl, , cinmethylin, curves and an expected EC50 calculated theoretically from cumyluron, cycluron, cyprazine, cyprazole, dibenzyluron, the formula: US 9,049,866 B2 8 Example 3 a + b eap C t In an oilseed rape field, ClomaZone, and pethoxamid were EC50(A).obs " EC50(B) obs applied individually and in combination to different plots by spraying. 206 days after application the rate of control of Viola arvensis was recorded. Results are provided in table 3. whereina and b are the weight ratios of compound A and B in The expected control is calculated according to the Colby the mixture and EC50obs is the experimentally determined method. EC50 value obtained using the dose response curves for the individual compounds. The ratio EC50(A+B)expected/EC50 10 TABLE 3 (A+B) observed expresses the factor of interaction (F) (syn ergy factor). In case of synergism, F is >1. For a more detailed Active Substance g. AI Control Expected description of the Wadley method, see Levi et al., EPPO (AI) hectare observed (O) % control (E)% Clomazone 72 O Bulletin 16, 1986, 651-657. Pethoxamid 1200 50 The invention is illustrated by the following examples: 15 Clomazone + Pethoxamid 72 - 1200 63 50 (1.26) The herbicidal compounds A and B were applied in the formulation in which they are present as commercially avail () indicates the synergism ratio R. able product. Damage by the herbicidal compositions was evaluated with reference to a scale of 0% to 100% in com Example 4 parison with untreated control plots. 0 means no damage and 100 means complete destruction of the harmful plants. In an oilseed rape field, ClomaZone, and pethoxamid were applied individually and in combination to different plots by Example 1 spraying. 64 days after application the rate of control of Galium aparine was recorded. Results are provided in table 4. In a field of sunflowers, clomazone (rate of 90 g/ha) and 25 The expected control is calculated according to the Colby pethoxamid (rate of 1200 g/ha) were applied individually and method. in combination (90+1200 g/ha) to different plots by spraying. 55 days after application the rate of control of various weeds TABLE 4 was recorded. Results are provided in table 1. The expected 30 Active Substance g. AI Control Expected control is calculated according to the Colby method. (AI) hectare observed (O) % control (E)% TABLE 1. Clomazone 72 40 Pethoxamid 1200 O Active Substance Control Expected Clomazone + Pethoxamid 72 - 1200 81 40 (2.03) 35 Weed (AI) observed (O) % control (E)% () indicates the synergism ratio R. Echinochloa Clomazone 50 crus-gali Pethoxamid 47 Clomazone + 94 74 (1.28) Example 5 Pethoxamid Soianum Clomazone 37 40 nigrum Pethoxamid 47 The volatility of clomazone in clomazone/pethoxamid Clomazone + 87 67 (1.31) mixtures as well as straight clomaZone in emulsifiable con Pethoxamid centrate (EC) and microcapsule Suspension (CS) formula tions was tested. The following formulations were prepared, () indicates the synergism ratio R. wherein the microcapsule Suspensions are mixtures of micro 45 capsules comprising the individual active ingredients: Example 2 TABLE 5 In a field of sunflowers, clomazone (rate of 90 g/ha) and Formulation type a.i. content: pethoxamid (rate of 1200 g/ha) were applied individually and 1 - (CS) 400 g/l pethoxamid + 35 g/l clomazone in combination (90+1200 g/ha) to different plots by spraying. 2 - (EC) 400 g/l pethoxamid + 24 g/l clomazone 50 days after application the rate of control of various weeds 3 - (CS) 360 g/l clomazone was recorded. Results are provided in table 2. The expected 4- (EC) 500 g/l clomazone control is calculated according to the Colby method. 55 Test plants (newly germinated wheat seeds; Vinjet) were TABLE 2 planted in 81 cm pots. 30 ml formulation (diluted as to Active Substance Control Expected comprise 0.5 g/l of clomaZone) in Small glass bowls was Weed (AI) observed (O) % control (E)% placed at the bottom of each of the four desiccatorjars. Plants Mercuriais Clomazone 13 were placed in petri dishes with moistened filter paper. In 60 (iiii Pethoxamid 27 every desiccator, four pots of wheat were placed on the top of Clomazone + 76 37 (2.08) the plates and each trial setup was covered with the desiccator Pethoxamid lid (open at the top). After 72 hours, the plants were removed Ambrosia Clomazone 10 from the desiccators. The development of foliar injury due to artemisiifolia Pethoxamid 10 Clomazone + 100 19 (5.26) clomaZone vapor was evaluated and scored visually after 7 Pethoxamid 65 and 11 days (average). ClomaZone caused easily notable foliar injuries such as bleaching and tip-burning. Results are provided in the below table US 9,049,866 B2 10 TABLE 6 8. The method according to claim 1, wherein the weight ratio of compounds A:B ranges from 1:10 to 1:15. 20 Phytotoxicity 9. The method according to claim 1, comprising applying Formulation Day 7 Day 11 90 g/ha of compound A and 1200 g/ha of compound B. 10. The method according to claim 1, comprising applying Control (noa.i.) O O 72 g/ha of compound A and 1200 g/ha of compound B. 1 - (CS) - pethoxamid + clomazone 33 41 2 - (EC) - pethoxamid + clomazone 25 23 11. A synergistic herbicidal composition comprising com 3 - (CS) - clomazone 75 85 pound A and compound B, wherein compound A is cloma 4 - (EC) - clomazone 78 65 Zone, compound B is pethoxamid, and the weight ratio of 10 compounds A:B ranges from 1:5 to 1:25, wherein clomazone Plants exposed to formulations containing only clomaZone and pethoxamid are the only active herbicidal compounds in showed a higher level of foliar injury than plants exposed to the composition. mixtures of pethoxamid and clomaZone. 12. A composition according to claim 11, wherein com The invention claimed is: pound A and compound B are present in a form selected from 1. A method for controlling harmful plants comprising 15 the group consisting of ready-to-use solutions, emulsifiable exposing the harmful plants to a synergistically effective concentrates, emulsions, Suspensions, wettable powders, amount of a combination of compound A and compound B, soluble powders, granules, soluble granules, dispersible wherein compound A is clomaZone, compound B is pethoxa granules, microemulsions, microcapsule Suspensions and mid, and the method comprises applying from 10 to 200 g/ha mixtures thereof. of compound A and from 100 to 3000 g/ha of compound B in 13. The composition according to claim 11, wherein the a weight ratio of compounds A:B ranging from 1:5 to 1:25 to weight ratio of compounds A:B ranges from 1:8 to 1:20. the harmful plants, wherein clomaZone and pethoxamid are 14. The composition according to claim 11, wherein the the only active herbicidal compounds in the combination. weight ratio of compounds A:B ranges from 1:10 to 1:15. 2. A method according to claim 1, wherein the harmful 15. A method for reducing the volatility of clomazone, the plants are present together with useful plants. 25 method comprising combining a synergistically effective 3. The method according to claim 2, wherein the useful amount of compound A and an amount of compound B effec plants are selected from the group consisting of maize, soya, tive to reduce the volatility of compound A, wherein com pea, bean, Sunflower, oilseed rape, Sugar cane, cassaya, pound A is clomaZone, compound B is pethoxamid, and the pumpkin, potato, vegetables and tobacco. weight ratio of compounds A:B ranges from 1:5 to 1:25, 4. The method according to claim 1, wherein the harmful 30 wherein clomaZone and pethoxamid are the only active her plants are selected from the group consisting of grasses, bicidal compounds. annual and perennial monocotyledonous and dicotyledonous 16. The method according to claim 15, wherein the weight plants. ratio of compounds A:B ranges from 1:8 to 1:20. 5. The method according to claim 1, comprising applying 17. The method according to claim 15, wherein the weight from 500 to 2500 g/ha of compound B. 35 ratio of compounds A:B ranges from 1:10 to 1:15. 6. The method according to claim 1, comprising applying 18. The method according to claim 15, comprising apply from 50 to 150 g/ha of compound A and from 800 to 1500 g/ha ing 35 g/l of compound A and 400 g/l of compound B. of compound B. 19. The method according to claim 15, comprising apply 7. The method according to claim 1, wherein the weight ing 24 g/l of compound A and 400 g/l of compound B. ratio of compounds A:B ranges from 1:8 to 1:20. k k k k k