IE904095A1 - Synergistic composition and method for the selective control¹of weeds - Google Patents

Abstract

The invention relates to a herbicidal agent containing, as compound of the formula I, 2-(3-chloro-5-trifluoromethylpyridin-2-ylcarbonyl)-cyclohex-1-en-1-ol- 3-one besides a synergistically active amount of a further herbicide a) of the formula II or b) of the formula III or c) of the formula IV or d) of the formula V where the radicals R<1> to R<9>, A and E have the meaning given in the text of the application, or one of the compounds e) 2-tert-butyl-3-cyano-4-methylaminocarbonylpyrrole, or f) 3-isopropyl-1H-2,1,3-benzothiadiatin-4(3H)-one 2,2-dioxide, or g) N-chloroacetyl-N-isopropyl-3,3,6-trimethylcyclohex-1-ene. The invention furthermore relates to a process for the selective control of weeds in crops of useful plants, and to the use of these agents for controlling weeds in crops of useful plants.

Description

Synergistic composition and method for the selective control of weeds The present invention relates to a synergistic composition containing a herbicidal combination of active ingredients. The composition according to the invention is suitable for the selective control of weeds in crops of useful plants, especially in maize.

The invention relates also to a method of controlling weeds in crops of useful plants, preferably in maize, sugar cane and other cultures and to the use of this novel composition.

From EP-A 353 187, respectively the South-African patent No 89/5610 has been known 2-(3-chloro-5-trifluoromethylpyridin-2-yl-carbonyl)-cyclohex-l-ene-l-ol-3-one of the formula I Z -CFj (I).

This compound has good selective herbicidal action against weeds in crops of useful plants.

In addition, the compounds of formulae II to VIII are known as herbicidal active ingredients some of which exhibit good selectivity in crops of useful plants. Some of the compounds of formulae II to VIII are commercially available.

There may be mentioned as compounds of formulae II to VIII: - 2 a) 2-Chloro-4-ethylamino-l,3,5-triazines of formula II A • · C2H5-NH7 ^NHR1 wherein R1 is isopropyl, tert.-butyl or 1-cyano-l-methylethyl and R2 is chlorine or methylthio.

Formula II includes especially the following individual compounds: Ila) 2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine, common name atrazine (described in The Pesticide Manual, 8th ed. (1987), p. 36, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) lib) 2-chloro-4-ethylamino-6-(l-cyano-l-methylethylamino)-l,3,5-triazine; common name cyanazine; (described in The Pesticide Manual, 8th ed. (1987), p. 198, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) lie) 2-chloro-4-ethylamino-6-tert.-butylamino-1,3,5-triazine; common name terbuthylazine; (described in The Pesticide Manual, 8th ed. (1987), p. 778, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB). lid) 2-methylthio-4-ethylamino-6-tert-butylamino-l,3,5-triazine; common name terbutryne; (described in The Pesticide Manual”, 7th Ed. (1983) p. 515 Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB). b) Chloroacetanilides of formula III (III) wherein R3 is methyl or ethyl and R1* is methoxymethyl or 2-methoxy-l-methylethyl.

Formula III includes, especially, the following individual compounds: Ilia) 2-chloro-2'-ethyl-6'-methyl-N-(2-methoxy-l-methylethyl)-acetanilide; common name metolachlor; (described in The Pesticide Manual 8th ed. (1987), p. 568, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) and lllb) 2-chloro-2',6'-diethyl-N-methoxymethyl-acetanilide; common name alachlor; (described in The Pesticide Manual, 8th ed. (1987), p. 5, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) . lllc) 2-chloro-N-ethoxymethyl-6'-ethyl-acet-o-toluidid; common name acetochlor; (described in The Pesticide Manual, 8th Ed.

C.R. Worthing; The British Crop Protection Coucil, Thornton Heath, GB) and c) Phenols of formula IV .A II (IV) wherein R6 is bromine or iodine and R5 is CN or the radical —C=N—O— when R7 i is hydrogen, or R5 is CN when R6 is CO-(CH2)6-CH3· Formula IV includes, especially, the following individual compounds: IVa) 3,5-dibromo-4-hydroxybenzaldehyde 2,4-dinitrophenyloxime; common name bromofenoxim; (described in The Pesticide Manual, 8th Ed. (1987), p. 94, Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) IVb) 4-hydroxy-3,5-dibromobenzonitrile; common name bromoxynil; (described in The Pesticide Manual, 8th ed. (1987), p. 100, Ed.

C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB) d) Phenylsulfonylureas of the formula V (V) wherein - 5 A is a radical z \_ \ / • “ · \io or E is nitrogen or the methine group —C=, R8 and R9 are independently of each other methyl, methoxy, chlorine or halomethoxy, R10 is halogen, methoxycarbonyl, 2-chloroethoxy, 2-methoxyethoxy, R11 is halogen or Cj-Cualkyl, R12 , R1 3 and R1* independently of each other are Ci-Cjalkyl.

Formula V includes especially the following individual compounds: Va) N-(2-methoxyethoxyphenylsulfonyl)-N’-(4,6-dimethoxy-l,3,5-triazin2-yl)-urea; common name cinosulfuron (described in EP-A 44 807 or in USP 4 479 821).

Vb) N-(2-chloroethoxyphenylsulfonyl)-3-(4-methoxy-6-methyl-l,3,5-triazin2-yl)-urea; common name triasulfuron (described in EP-A 44 808 or USP 4 514 212).

Vc) N-[2-(methoxycarbonyl)phenyl]sulfonyl-N'-(4,6-bis-difluormethoxypyridin-2-yl)-urea, common name primisulfuron (described in EP-A 84 020 or in USP 4 478 635).

Vd) N-[2-(3-dimethylaminocarbonylpyridin-2-yl)-sulfonyl]-N1-(4,6-dimethoxypyridin-2-yl)-urea, known from EP-A 237 292.

Ve) N-(4-ethoxycarbonyl-l-methylpyrazol-5-yl-sulfonyl)-N’-(4,6-dimethoxypyridin-2-yl)-urea, known from JP-A 60/78980 or C.A. 104(1):5895 w. e) As a compound of formula VI > ,N, CHj C-CH3 ch3 (VI) An 2-tert. butyl-3-cyano-4-methylaminocarbonyl-pyrrole, code name EL 177 or GPA 151 867. f) As a compound of formula VII H \/\/\ 6 ' ‘ch(ch3)2 (VII), 3-isopropyl-lH-2,1,3-benzothiazin-4(3H)-one 2,2-dioxide; common name bentalone; (described in The Pesticide Manual, 8th Ed. (1987), p. 63 Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB). g) As compound of the formula VIII (VIII) N-chloroacetyl-N-isopropyl-3,3,5-trimethyl-cyclohex-l-ene, common name trimexachlor, (described in The Pesticide Manual, 9th Ed. (1990), Ed. C.R. Worthing; The British Crop Protection Council, Thornton Heath, GB). - 7 The compounds of formula I and the preparation thereof is described in EP-A 353 187 or the South African Patent No 89/5610 according to the following example: P.1.1.1. 2-(3-chloro-5-trifluoromethylpyridin-2-ylcarbonyl)-cyclohexl-en-l-ol-3-one 4.9 g (20 mmol) of 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid chloride are added dropwise to a solution of 2.2 g (20 mmol) of 1,3cyclohexanedione and 7 ml (50 mmol) of triethylamine in 25 ml of dichloromethane, the temperature rising to 35°C. The whole is then stirred at room temperature for 15 hours to complete the reaction. The black suspension is diluted with 250 ml of dichloromethane, adjusted to pH 1 with IN HCl at from 0 to 5°, and washed twice with H20. The product is subsequently extracted with 5 % NaHCO3 solution, precipitated cold with 37 % HCl, filtered with suction and dried. 4.0 g (63 %) of the title compound of formula Cl.

/’\ / \=· —CF: OH are isolated in the form of crystals having a melting point of 102-105°C The starting material and the preparation thereof are known or can be prepared according to known methods. 1,3-Cyclohexanedione e.g. can be prepared by a malonic acid synthesis in accordance with the scheme below.

If ? ft ft Z-CH3 COOH Z \ • · • + CH3O-CH -> H—' + ch2 -+ 1 1 H/ \ • COOH • · \ / % formaldehyde aceton_ H^ malonic acid • 0 - 8 3-Chloro-5-trifluoromethylpyridin-2-ylcarbonic acid chloride can be prepared in the known manner e.g. by fluorination of 3-chloro-5-methylpyridin-2-yl-carbonic acid ester, followed by saponification of the 3-chloro-5-trifluoromethylpyridin-2-yl carbonic acid ester and treating it with a strong halogenating agent.

It has surprisingly been found that a quantitatively variable combination of two active ingredients, on the one hand compound I and, on the other hand, an active substance from the above-mentioned compound classes II to VIII, exhibits a synergistic action that is advantageously suitable for controlling weeds in crops of useful plants, especially in maize. These synergistic combinations are suitable for controlling the majority of important weeds, especially maize weeds, without damaging the cultivated plant.

The principal weeds in cereal crops, such as species of the monocotyledonous genera Alopecurus, Avena and Setaria, and of the dicotyledonous genera Chrysanthemum, Galium, Sinapis, Stellaria and Veronica, are destroyed selectively both in the pre-emergence and the post-emergence process.

There is therefore proposed according to the present invention a novel synergistic composition for the selective control of weeds that contains as active ingredient 2-(3-chloro-5-trifluoromethyl-pyridin-2-ylcarbonyl)cyclohex-l-ene-l-ol ,of the formula I CFj (I) together with a synergistically effective amount of a further active ingredient - 9 a) of formula II A • · C2H5-nZ ^NHR1 wherein R1 is isopropyl, tert.-butyl or 1-cyano-l-methylethyl and R2 is chlorine or methylthio, or b) of formula III C1CH2 C2Hs Y* • R3 \ / i (III) wherein R3 is methyl or ethyl and R1* is methoxymethyl or 2-methoxy-l-methylethyl, or c) of formula IV R6 II I y\> ό R7 (IV) wherein R6 is bromine or iodine and R5 is CN or the radical • — · -C=N-O—NO 2 when • — · o2n/ R7 is hydrogen, or R5 is CN when R7 is CO-(CH2)6-CH3, or d) of formula V A-SOz-NH z Λ\ (V) wherein A is a radical • — · \ z \io or E is nitogen or the methine group —C=, R* and R9 independently of each other are methyl, methoxy chlorine or halomethoxy, R10 is halogen, methoxycarbonyl, 2-chloroethoxy, 2-methoxyethoxy, Rl 1 is hydrogen or Ci-C<,alkyl, R1 2 , R13 and R1* independently of each other are Ci-C3alkyl or e) of the formula VI 0N (VI), or f) of formula VII V\/\ (VII), or g) of the formula VIII ch(ch3)2 (VIII) and, if desired, other adjuvants and/or carriers.

Attention is drawn to a composition according to the invention that contains, in addition to the compound of formula I, a synergistically effective amount of a compound of formula Ila, lie, Ilia, Illb, IVb, VI, VII, or VIII.

The active ingredient combinations according to the invention can be used both pre-emergence and post-emergence. In addition, the seeds of the cultivated plant can be treated with a herbicidally effective amount of active ingredient combination according to the invention (seed dressing). The active ingredient combination according to the invention is thus applied when the seeds of the cultivated plants are sown.

A combination of compound I with the compounds of the formula II, III, V, VI or VIII is especially suitable for post-emergence application while a combination of compound I with compounds of formula III is preferred for pre-emergence application. - 12 The active ingredient combinations according to the invention are especially suitable for maize.

It is extremely surprising that a combination of the compound of formula I with a compound of formula II, III, IV, V, VI or VII not only brings about an additive broadening of the spectrum of action to cover weeds that are normally associated with maize, which would be expected in principle, but also achieves a synergistic effect that broadens in two respects the range of action of the active substances that are combined with one another.

Firstly, the rates of application of the individual compounds I, II, III, IV, V, VI, VII or VIII are markedly reduced while the high level of action is maintained. Secondly, the combined mixture still achieves a high degree of weed control even in cases where the two compounds individually were entirely ineffective when used at too low a rate of application. The result of this is a considerable broadening of the weed spectrum and an additional increase in the safety margin in maize, as is necessary and desirable in case of inadvertent overdosage of the active ingredient.

The active ingredient combination according to the invention preferably contains the compounds of formula II, III, IV, V, VI or VII in the same amount as compound I or in excess relative to the amount of compound I.

The mixture ratio can be chosen as desired within wide limits. Ratios of I to II, III, IV, V, VI, VII or VIII of from 1:1 to 1:500, especially from 1:2 to 1:200, and, more especially, from 1:2 to 1:100, are preferred.

The optimum ratios of the individual compound components can be determined by biological tests. - 13 The ratios of the individual compound components can vary in accordance with the type of weed to be controlled and in dependence on the particular form of application.

The active ingredient combinations according to the invention exhibit excellent action against weeds, without affecting the useful plant crop to any appreciable extent, at a rate of application of from 0.005 to 3.0 kg, preferably from 0.01 to 1.0 kg, of active substance per hectare .

The formulations, i.e. the compositions, preparations or mixtures containing the compound (active ingredient) mixture according to the invention and, where appropriate, a solid or liquid adjuvant, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with extenders, e.g. solvents, solid carriers and, where appropriate, surface-active compounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, e.g. xylene mixtures or substituted naphthalenes, phthalates such as dibutyl phthalate or dioctyl phthalate, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethylformamide, as well as vegetable oils or epoxidised vegetable oils, such as epoxidised coconut oil or soybean oil; or water.

The solid carriers used e.g. for dusts and dispersible powders, are normally natural mineral fillers such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are, for example, calcite or sand. In - 14 addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues e.g. cork powder or sawdust.

Particularly advantageous application-promoting adjuvants which are able to reduce substantially the rate of application are also natural (animal or vegetable) or synthetic phospholipids of the series of the cephalins and lecithins, e.g. phosphatidylethanolamine, phosphatidylserine, phosphatidylcholine, sphingomyelin, phosphatidylinositol, phosphatidylglycerol, lysolecithin, plasmalogens or cardiolipin, which can be obtained e.g. from animal or vegetable cells, especially the brain, heart, lung, liver, egg yolks or soybeans. Commercial mixtures that may be used are e.g. phosphatidylcholine mixtures. Synthetic phospholipids are e.g. dioctanoylphosphatidylcholine and dipalmitoylphosphatidylcholine.

Suitable surface-active compounds are non-ionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties. The term surfactants will also be understood as comprising mixtures of surfactants .

Both so-called water-soluble soaps and also water-soluble synthetic surface-active compounds are suitable anionic surfactants.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (Cio-C22), e.g. the sodium or potassium salts of oleic or stearic acid or of natural fatty acid mixtures which can be obtained e.g. from coconut oil or tallow oil. Mention may also be made of fatty acid methyllaurin salts.

More frequently, however, so-called synthetic surfactants are used, especially fatty sulfonates, fatty sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates. - 15 The fatty sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts and contain a Cg-Czzalkyl radical which also includes the alkyl moiety of acyl radicals, e.g. the sodium or calcium salt of lignosulfonic acid, of dodecylsulfate or of a mixture of fatty alcohol sulfates obtained from natural fatty acids. These compounds also comprise the salts of sulfated and sulfonated fatty alcohol/ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms. Examples of alkylarylsulfonates are the sodium, calcium or triethanolamine salts of dodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, or of a condensate of naphthalenesulfonic acid and formaldehyde.

Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14 moles of ethylene oxide.

Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, saturated or unsaturated fatty acids and alkylphenols, said derivatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylenediaminopolypropylene glycol and alkylpolypropylene glycol containing 1 to 10 carbon atoms in the alkyl chain, which adducts contain 20 to 250 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. These compounds usually contain 1 to 5 ethylene glycol units per propylene glycol unit.

Representative examples of non-ionic surfactants are nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol. - 16 Fatty acid esters of polyoxyethylene sorbitan, e.g. polyoxyethylene sorbitan trioleate, are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts which contain, as N-substituent, at least one Ce-C22-alkyl radical and, as further substituents, unsubstituted or halogenated lower alkyl, benzyl or hydroxy-lower alkyl radicals. The salts are preferably in the form of halides, methylsulfates or ethylsulfates, e.g. stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in the art of formulation are described, inter alia, in the following publications: 1985 International Me Cutcheon's Emulsifiers & Detergents, Glen Rock NJ USA, 1985, H. Stache, Tensid-Taschenbuch, 2nd edition, C. Hanser Verlag, Munich, Vienna 1981, M. and J. Ash, Encyclopedia of Surfactants, Vol. I-III, Chemical Publishing Co., New York, 1980-1981.

The agrochemical compositions usually contain 0.1 to 95 %, preferably 0.1 to 80 %, of the mixture of compounds of the formulae I and II, III, IV, V, VI, VII or VIII, 1 to 99.9 % of a solid or liquid adjuvant, and 0 to 25 %, preferably 0.1 to 25 %, of a surfactant.

Preferred formulations are made up, especially, as follows: (throughout, percentages are by weight).

Emulsifiable concentrates active ingredient mixture: 1 to 20 %, preferably 5 to 10 % surface-active agent: 5 to 30 %, preferably 10 to 20 % liquid carrier: 50 to 94 %, preferably 70 to 85 % - 17 Dusts active ingredient mixture: 0.1 to 10 %, preferably 0.1 to 1 % solid carrier: 99.9 to 90 %, preferably 99 .9 to Suspension concentrates active ingredient mixture : 5 to 75 %, preferably 10 to 50 water: 94 to 25 %, preferably 88 to 30 surface-active agent: 1 to 40 %. preferably 2 i to 30 1 Wettable powders active ingredient mixture: surface-active agent solid carrier: Granulates active ingredient mixture: solid carrier: 0.5 to 90 /0 , preferably 0.5 to 20 %, preferably 5.0 to 95 %, preferably to 80 % to 15 % 15 to 90 % 0.5 to 30 %, 99.5 to 70 %, preferably 3 to 15 % preferably 97 to 85 % Whereas commercial products will preferably be formulated as concentrates, the end user will normally employ dilute formulations. The forms of application can be diluted to concentrations as low as 0.001% of active ingredient.

Other biocidal active ingredients or compositions can be mixed with the described compositions according to the invention. For example, the novel compositions may contain, in addition to the mentioned compounds of the general formula I and of the formula II, III, IV, V, VI, VII or VIII, insecticides, fungicides, bactericides, fungistatics, bacteriostatics or nematicides in order to broaden the spectrum of action. - 18 The compositions according to the invention can generally be formulated in detail, in accordance with the following Examples: Formulation Examples Example Fl: Formulation Examples for synergistic active ingredient mixtures of the formulae I and II, III, IV, V, VI, VII or VIII (throughout, percentages are by weight) a) Wettable powders a) compound I and 10 % one of the compounds II, III, IV, V, VI, VII and VIII 10 % sodium lignosulfonate 5 % sodium lauryl sulfate 3 % sodium diisobutylnaphthalenesulfonate b) c) d) % 5 % 30 % % 15 % 30 % % 5 % 5 % % % - 6 % octylphenol polyethylene glycol ether (7-8 moles of ethylene oxide) highly dispersed silicic acid 5 % kaolin 67 % % - 2 % % 5 % 27 % % The active ingredient mixture is thoroughly mixed with toe adjuvants and the mixture is thoroughly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of the desired concentration. - 19 b) Emulsifiable concentrate a) compound I and 5 % one of the compounds II, III, IV, V, VI, VII and VIII 5 % octylphenol polyethylene glycol ether (4-5 moles of ethylene oxide) 3 % calcium dodecylbenzenesulfonate 3 % castor oil polyglycol ether (36 moles of ethylene oxide) 4 % cyclohexanone 30 % xylene mixture 50 % b) c) % 12 % % 13 % % 3 % % 2 % % 4 % % 31 % % 35 % Emulsions of any required concentration can be obtained from this concentrate by dilution with water. c) Dusts a) compound I and 2 % one of the compounds II, III, IV, V, VI, VII and VIII 3 % talcum 95 % kaolin c) d) % 4 % % 8 % % % Ready-for-use dusts are obtained by mixing the with the carrier and grinding the mixture in a active ingredient mixture suitable mill. d) Extruder granulate compound I and one of the compounds II, III, IV, V, VI, VII and VIII sodium lignosulfonate carboxymethylcellulose kaolin a) b) c) % 3 % 5 % % 7 % 15 % % 2 % 2 % % 1 % 1 % % 87 % 77 % - 20 The active ingredient mixture is mixed and ground with the adjuvants, and the mixture is subsequently moistened with water. The mixture is extruded and then dried in a stream of air. e) Coated granulate compound I and one of the compounds II, III, IV, V, VI, VII and VIII polyethylene glycol (mol. wt. 200) kaolin a) b) 1.5 % 3 % 1.5 % 5 % % 3 % % 89 % The finely ground active ingredient mixture is uniformly applied, in a mixer, to the kaolin moistened with polyethylene glycol. Non-dusty coated granulates are obtained in this manner. f) Suspension concentrate compound I and one of the compounds II, III, IV, V, VI, VII and VIII ethylene glycol nonylphenol polyethylene glycol ether (15 moles of ethylene oxide) sodium lignosulfonate carboxymethylcellulose % aqueous formaldehyde solution silicone oil in the form of a 75 % aqueous emulsion water a) b) % 20 % % 40 % % 10 % % 6 % % 10 % % 1 % 0.2 % 0.2 % 0.8 % 0.8 % % 12 % The finely ground active ingredient mixture is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentration can be obtained by dilution with water. - 21 A synergistic effect is always present in the case of herbicides when the herbicidal action of the combination of compounds I and II, III, IV, V, VI, VII or VIII is greater than the total action of the active ingredients applied individually.

The expected herbicidal action Ae for a given combination of two herbicides can be calculated as follows (cf. COLBY, S.R., Calculating synergistic and antagonistic response of herbicide combinations, Weeds 15, pages 20-22, 1967): Ae γ χ Y * (100-X) 100 in which: X = percentage inhibition of growth in the case of treatment with a herbicide I at a rate of application of £ kg per hectare in comparison with the untreated control (= 0 %) Y = percentage inhibition of growth in the case of treatment with a herbicide II, III, IV, V, VI, VII or VIII at a rate of application of q kg per hectare in comparison with the untreated control Ae = expected herbicidal action (percentage inhibition of growth in comparison with the untreated control) after treatment with herbicide mixture I and II, III, IV, V, VI, VII or VIII at a rate of application of p + q kg active ingredient per hectare.

If the action actually observed is greater than the expected value Ae then synergism has been achieved.

The synergistic effect of the combinations of compounds I and II, III, IV, V, VI, VII or VIII is demonstrated in the following Examples. - 22 Biological Examples: Example Bl: Pre-emergence test In a greenhouse, the seeds of the test plants are sown in plastic pots containing 0.5 1 of sterilised soil. One day after sowing, the surface of the soil is sprayed with an aqueous dispersion of the active ingredient combination.

The rate of application of the active substance is adjusted by suitable dilution of the concentrate. 50 ml of dispersion are sprayed per m2. The test plants are further cultivated in the greenhouse and are watered daily. An evaluation is made 20 days after sowing and application. The percentage inhibition of growth is recorded in comparison with the untreated control plants. The following linear scale was used as a rating: 100 % = plants withered 50 % = medium effect % = as untreated control plants The results of the test are shown together with the expected values, calculated in accordance with the above-mentioned Colby formula, in Tables 1) and 2). The Tables indicate the rates of application of the active ingredients and also the tested cultivated plants and weeds.

In Tables 1) and 2), the expected values for the test plant, calculated according to Colby, are shown in column Ae in comparison with the values in column W which were ascertained experimentally.

Pre-emergence activity in mixtures of compounds of formulae H-II, III and VIII The test was evaluated 20 days after application. The activity was compared with that of not treated plants (=0 % herbicidal acitvity). - 23 Table 1 Synergistic action with Amranthus retroflexus in the preemergence test herbicidal action in % measured expected (according to Colby) + /- compound Ilia (metolachlor) 0.125 kg/ha 0 compound I 0.250 kg/ha 60 compound Ilia + compound I 0.125 + 0.250 kg/ha 100 60 +40 compound VIII (trimexachlor) 0.250 kg/ha 25 compound I 0.250 kg/ha 60 compound VIII + compound I 0.250 + 0.250 kg/ha 100 40 +60 Table 2 Synergistic action with Xanthium in the pre-emergence test herbicidal action in % measured expected (according to Colby) + /- compound Ilia (metolachlor) 0.125 kg/ha compound I 0.250 kg/ha compound Ilia + compound I 0.125 + 0.250 kg/ha 0 50 80 50 + 30 compound Ila (atrazine) 0.250 kg/ha compound I 0.250 kg/ha compound Ila + compound I 0.250 + 0.250 kg/ha 25 60 90 64 +26 - 24 Example B2: Post-emergence test The test plants are grown in plastic pots containing 0.5 1 of sterilised soil. After emergence, the plants are sprayed in the 2-3 leaf stage (about 2 weeks after sowing) with an aqueous dispersion of the active ingredient combinations. The amount of spray liquor is 50 ml per a2. The rate of application of active substances is adjusted by suitable dilution of the concentrate. The test plants are further cultivated in the greenhouse and are watered daily. An evaluation is made 20 days after application. The degree of damage to the plants is evaluated as a percentage in accordance with the same rating as was used in the pre-emergence test.

The results of the test are shown together with the expected values, calculated in accordance with the above-mentioned Colby formula, in the following Tables 3 and 4 . Each table indicates the rates of application of the active ingredients and also the tested cultivated plants and weeds. - 25 Post-emergence activity of mixtures of compounds I + II, III, IV, V, VI and VII Table 3 Synergistic action with Agropyron in the post-emergence test herbicidal action in % measured expected (according to Colby) + /- compound Ila (atrazine) 0.25 kg/ha 10 compound I 0.5 kg/ha 0 compound Ila + compound I 0.25 + 0.5 kg/ha 90 10 +80 compound lie (terbuthylazine) 0.5 kg/ha 20 compound I 0.5 kg/ha 0 compound lie + compound I 0.5 + 0.5 kg/ha 60 20 +40 compound Vc (primisulfurone) 0.03 kg/ha 20 compound I 0.5 kg/ha 0 compound Vc + compound I 0.03 + 0.5 kg/ha 50 20 + 30 compound IVb (bromoxynil) 1.0 kg/ha 0 compound I 0.5 kg/ha 0 compound IVb + compound I 1.0 + 0.5 kg/ha 50 0 + 50 - 26 Table 4 Synergistic action with Convolvulus in the post-emergence test herbicidal action in % measured expected (according to Colby) + /- compound Ila (atrazine) 0.25 kg/ha 20 compound I 0.5 kg/ha 50 compound Ila + compound I 0.25 + 0.25 kg/ha 95 60 +35 compound VII (hentazone) 0.5 kg/ha 25 compound I 0.25 kg/ha 50 compound VII + compound I 0.5 + 0.25 kg/ha 95 63 +32 compound VI (EL 177) 0.25 kg/ha 0 compound I 0.25 kg/ha 50 compound VI + compound I 0.25 + 0.25 kg/ha 98 50 +48

Claims (15)

1. Patent claims

1. A herbicidal composition containing as active ingredient

2. -(3-chloro-5-trifluoromethylpyridin-2-y1-carbonyl)-cyclohex-1-en-l-ol) of the formula ff • — · / \ Y_Z Ah ./ Y —CF 3 (I) together with a synergistically effective amount of a further active ingredient a) of formula II f > (II) • · C 2 H 5 -NH 7 Ύ ^NHR 1 wherein R 1 is isopropyl, tert.-butyl or 1—cyano—1—methylethyl, R 2 is chlorine or methylthio, or b) of formula III ClCH 2 -< C z H 5 V' ΥΛ (in) wherein R 3 is methyl or ethyl and R 1 * is methoxymethyl, ethoxymethyl or 2-methoxy-l-methylethyl, or - 28 c) of formula IV r z\ IJ I r &/ \ 6 ό R 7 wherein R 6 is bromine or iodine and R 5 is CN or the radical • — · -C=N-O-Z no 2 when — · o 2 n / R 7 is hydrogen, or R 5 is CN when R 7 is CO-(CH 2 )6-CH 3 , or d) of formula V (IV) A-SO 2 -NH (V) wherein A is a radical \io Z • — · z \ 'W —OR 1 ‘ or E is nitrogen or the methine group —C=, R 8 and R 9 independently of each other are methyl, methoxy, chlorine or halomethoxy, - 29 R 1 ® is halogen, methoxycarbonyl, 2-chloroethoxy or 2-methoxyethoxy, Z Z and R 14 , independently o f each other are C. -C’alkyl, 11 i j R is halogen or C^-C^alkyl, or ·) of the formula (VI), or f) of the formula VII or II I \S CH(CHj); (VII), g) of the formula VIII ClCHj?-y-£H-^3h HjC— ^A. zC h, (VIII) CHj and, if desired, other adjuvants and/or carriers. - 30 2. A herbicidal composition according to claim 1, containing as compound of formula II 2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine or 2-chloro-4-ethylamino-6-(1-cyano-1-methylethylamino)-l,3,5-triazine or 2-chloro-4-ethylamino-6-tert.-butylamino-1,3,5-triazine. 2-methylthio-4-ethylamino-6-tert. butylamino-1,3,5-triazine.

3. A herbicidal composition according to claim 1, containing as compound of formula III 2-chloro-2'-ethyl-6 1 -methyl-N-(2-methoxy-1-methylethyl)acetanilide or 2-chloro-2',6'-diethyl-N-methoxymethylacetanilide. 2-chloro-N-ethoxymethyl-6 1 -ethyl-acet-O-toluidide.

4. A herbicidal composition according to claim 1, containing as compound of formula IV 3.5- dibromo-4-hydroxybenzaldehyde 2,4-dinitrophenyloxime or 3.5- dibromo-4-hydroxybenzonitrile .

5. A herbicidal composition according to claim 1, containing as compound of formula V N-(2-methoxyethoxypheny1sulfonyl)-N'-(4,6-dimethoxy-l,3,5-triazin-2-yl)urea, N-(2-chloroethoxyphenylsulfonyl)-N'-(4-methoxy-6-methy1-1,3,5-triazin-2yl)-urea N-[2-(methoxycarbonyl)phenylsulfonyl]-N'-(4,6-bis-difluormethoxypyridin-2-yl)-urea N-[2-(3-Dimethylaminocarbonylpyridin-2-yl)-sulfonyl]-N'-(4,6-dimethylpyridin-2-yl)-urea N-(4-ethoxycarbonyl-1-methylpyrazole-5-ylsulfonyl)-N'-(4,6-dimethylpyrimidin-2-yl)-urea.

6. A herbicidal composition according to claim 1, containing as compound of formula VI 2-tert. butyl-3-cyano-4-methylaminocarbonyl-pyrrole.

7. A herbicidal composition according to claim 1, containing as compound of formula VII 3-isopropyl-lH-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide .

8. A herbicidal composition according to claim 1, containing as compound of formula VIII N-chloromethyl-N-isopropyl-3,3,5-trimethyl-cyclohex-l-ene.

9. A herbicidal composition according to claim 1, containing 1 part by weight of the compound of formula I together with from 0.001 to 10 parts by weight of a compound of formula II, III, IV, V, VI, VII or VIII.

10. Seed of culture plant that has been treated with a herbicidally effective amount of a composition according to any one of claims 1 to 11.

11. A method for the selective pre- and post-emergence control of weeds in crops of useful plants, wherein a herbicidally effective amount of a composition according to claim 1 is applied to the crop of useful plants or its locus.

12. A method according to claim 11 for the selective control of weeds in crops of useful plants, which comprises the use of treated seed.

13. A herbicidal composition according to claim 1, substantially as hereinbefore described and exemplified.

14. Seed according to claim 10, substantially as hereinbefore described.

15. A method according to claim 11, substantially as hereinbefore described and exemplified.