IE83260B1 - Synergistic herbicidal agents - Google Patents

Description

SYNERGISTIC HERBICIDAL AGENTS HOECHST SCHERING AGREVO GMBH - The invention is in the field of the crop protection agents which can be employed against nmnocotyledon and dicotyledon weeds, in particular in the combinations of herbicides.

The action of an individual herbicide used in acceptable application rates is frequently insufficient for con- trolling the spectrum of nwnocotyledon and dicotyledon weeds which exists in agricultural practise. To allow the grower to control the weed spectrum in cereals, maize and other crops with one or a few application(s) of herbicidal active substances, it is sometimes nmre suitable to use combinations of a variety of active substances. Synergistic combinations of amidosulfuron (with fenoxaprop-ethyl, ioxynil and isoproturon) are already part of the prior art (EP—A-298,901, EP-A- l,677 and EP-A-401,678).

Further combinations of herbicides have now been found whose action, surprisingly, exceeds the extent which would have been expected taking into account the individual action of the components. The combinations of herbicides, according to the invention, therefore allow a surprisingly’ great reduction in. application. rate of each of the components. therefore relates to herbicidal ‘com- The invention positions which comprise A) a compound of the formula I or salts thereof in combination with B) diflufenican in a synergistically active amount.

The compound of the formula (I) is known as amidosulfuron and disclosed in EP—A-0,131,258 (US-A- 4,718,937).

Amidosulfuron is a. herbicidally’ active substance from the group comprising the sulfonylureas and is generally rice and 120 g of a.i./ha, controlling a broad spectrum of annual and perennial applied pre- and. post-emergence in cereals, maize at application rates of 5 — broad-leaf weeds and Cyperaceae (g of a.i./ha = gram per hectare based on active ingredient). For use, the active substance is generally formulated as a WP (water-soluble powder) or WDG (water—dispersible granules) and employed in the customary manner in the form of a dilution with water.

N-(2,4—difluorophenyl)—2-[3-(tri- is employed Diflufenican, i.e. fluoromethyl)phenoxy]pyridinecarboxamide, pre- and post—emergence for controlling weeds in cereals 500 g of a.i./ha. It is marketed mostly in the form of readymixes together and other crops at a rate of 50 — with other herbicidally active substances (cf. "The Pesticide Manual", British Crop Protection Council, 9“ Edition 1991, and references cited therein.

In a further use form according to the invention, the and B) applied in combination with one or npre compounds from the the growth- regulator—type, nitrodiphenyl herbicidal agents frown A) may additionally be consisting of herbicides of dicamba group and its salts, ethers, sulfonylureas which differ from those of the formula (1), and their salts and selective grass herbicides.

Particularly ,suitable growth-regulator-type herbicides are the following: - a) MCPB i.e. 4-(4—chloro-2—methylphenoxy)- butanoic acid or salts thereof (for example the sodium salt); b) mecoprop i.e. 2-(4-chloro-2—methylphenoxy)- propionic acid or salts thereof; in the forn1 of a racemic mixture or as the (R)—isomer (mecoprop-P); ‘ c) 2,4-D i.e. 2-(2,4—dichlorophenoxy)acetic acid or salts thereof or esters thereof; d) 2,4-DB i.e. 4-(2,4-dichlorophenoxy)butanoic acid or salts thereof; e) dichlorprop i.e. 2-(2,4-dichlorophenoxy)propionic acid or salts thereof or esters there- of, f) MCPA i.e. 2-(4-chloro—2—methylphenoxy)acetic acid or salts thereof.

The abovementioned compounds a) to f) represent standard herbicides which are used post—emergence in a large number of for controlling broad-leaf weeds and Cyperaceae. agriculturally used crops Application rates of 100 - 3000 g of a.i./ha as individual active substances cover in each case a specific sector of the weed flora.

The various compounds are used in the forms of the salts "The Pesticide Manual", th Edition 1991 and and/or esters (references: cf.

British Crop Protection Council, references cited therein).

Dicamba, i.e. 3,6—dichloro-2—methoxybenzoic acid (or the salts thereof and esters thereof), herbicidal active substance which is applied analogously to the growth~regulator herbicides. The active substance is also a widely used is mainly used post—emergence (for example, inter alia, in the forum of the (cf. "The Pesticide in cereals and maize), likewise salts thereof and/or esters thereof Manual", already mentioned above).

Particularly suitable nitrodiphenyl ethers are the following: ' a) i.e. methyl application rate 50 — Bifenox, 5—(2,4-dichlorophenoxy)— 1000 g of a.i./ha when used as single active substance pre- —nitrobenzoate; and post-emergence, for example in cereals, rice and maize.

Fluorglycofen, i.e. carboxymethyl 5-[2-chloro- -(trifluoromethyl)phenoxy]nitrobenzoate; application as single active substance for example only 5 - 50 g of a.i./ha pre- and post-emergence in cereals and soya. i.e.

Acifluorfen, 5-[2—chloro—4-(trifluoromethy1)- phenoxy]nitrobenzoic acid or salts thereof; application as single active substance for example at a rate of 100 — 500 g of a.i./ha pre- and post- emergence in soya and cereals. i.e. 5-[2-chloro(trifluoromethyl)— application as dxyfluorfen, phenoxy]ethoxynitrobenzene; single active substance for example at a rate of 100 - 1000_g of a.i./ha pre- and post-emergence in soya or on areas not under cultivation.

Lactofen, i.e. 1-(ethoxycarbonyl)ethy1 5-[2-chloro- 4-(trifluoromethyl)phenoxy]nitrobenzoate; application as single active substance for example at a rate of 50 - 500 g of a.i./ha pre- and post- emergence in soya and cereals. i.e. N—methylsulfonyl—5-[2-chloro~4- (trifluoromethyl)phenoxy]nitrobenzamide; Fomesafen, application as single active substance for example at a rate of 50 - 1000 g of a.i./ha pre- and post- emergence in soya or cereals.

All of the ni;rophenyl ethers mentioned are described in “The Pesticide Manual" (already mentioned above). < _ 5 - Particularly suitable sulfonylureas are the following: sulfonylureas which are employed mainly in cereals, in some cases in potatoes and in grassland for post—emergence control of broad-leaf and grass weeds (for example at a rate of 5 - 80 g of agi./ha), for example aa) triasulfuron, i.e. 1-[2-(2-chloroethoxy)- phenylsulfonyl]—3-(4-methoxy—6—methy1- 1,3,5—triazinyl)—urea; ab) chlorsulfuron, i.e. l—(2—chlorophenyl— sulfonyl)(4—methoxy-6—methyl-1,3,5—triazin— 2-yl)-urea; i.e. ac) tribenuron or tribenuron-methyl, 1-[g- (carboxy— or methoxycarbonyl)phenylsulfonyl]— 3-methyl(4-methoxy—6-methyl-1,3,5-triazin— 2-yl)-urea; ad) thifensulfuron or thifensulfuron-methyl, i.e. 1-[2—(carboxy- or methoxycarbonyl)—thiophen yl-su1fonyl](4—methoxy—6—methyl—1,3,5- triazin—2-yl)-urea and sulfonylureas which are employed. mainly in. maize and perennial crops for post—emergence control of grass and broad-leaf weeds (5 — 80 g of a.i./ha), for example ba) nicosulfuron, i.e. 1-[3-(dimethylamino- carbonyl)—pyridin—2-yl—sulfonyl](4,6- dimethoxypyrimidin—2—yl)-urea; bb) primisulfuron or primisulfuron—methyl, i.e. 1- [2-(carboxy- or methylcarbonyl)—pheny1— su1fonyl][4,6-bis(difluoromethoxy)- pyrimidinyl]-urea; bc) DPX-E 9636, -yl—sulfonyl]-3—(4,6-dimethoxypyrimid—2—yl)- PCT Patent Application PCT/EP 90/023 (WO 91/10660) , those of the formula A1 or salts thereof preferably i, / ‘ 3* ‘S _o_ o , ..=( \ _5,-KH"|'L-8—<\ 1: (Al) N O }z_( — II in which E is CH or N, preferably CH, R‘ is iodine or NR9R1°, R5 is H, halogen, cyano, C1—C3—alkyl, C1—Cg— alkoxy, C1-C3—haloalkyl, C1—C3—haloalkoxy, C1-C3-alkylthio, (C1-C3—alkoxy) -C1-C3-alkyl, (C1-C3-alkoxy)-carbonyl, mono- or di-(C1-C3'- alkyl) -amino, C1-C3-alkyl-sulfinyl or -sulfonyl, SO;-N'R°Rb or CO-NR“Rb, in particular H, R‘ and R”, independently of one another are H, C1-C3-alkyl, C1-—C3—alkenyl, C1-C3-alkynyl, or together are — (CH2) 4- , - (CH2) 5- or -(C'H2)2'0“(C'H2)2'.

R‘ is H or CH3, R7 is halogen, C1-C2-alkyl, C1-C2-alkoxy, C1-C2- haloalkyl, preferably CF3, C1—C;—haloalkoxy, preferably OCHF2 or OCHZCF3, R8 is C1—C2—alkyl, C1-C2—haloalkoxy, preferably OCHF2 or C1-C2-alkoxy, and R9 is C1-C4-alkyl and R” is C1-C4-alkylsulfonyl, The herbicides mentioned above under aa) described in above) . or R9 and R” formula ‘(CH2)3SO2" or -(CH-2)4SO;-. together are a chain of the to ba) are "The Pesticide Manual" (already mentioned - _ 7 _ Primisulfuron and primisulfuron—methyl are known from Brighton Crop Protection Conference - Weeds - 1987, p. 41 - 48.

DPX-E 9636 is known from Brighton Crop Protection Conference - Weeds - 1989, p. 33 et seq..

Suitable grass herbicides are mainly the following herbicides for the selective post-emergence control of harmful plants (grass weeds and broad-leaf weeds) in dichlorophenoxy)phenoxy]propionic acid or its methyl ester; 2-[1-(ethoxyimino)-propyl] b) tralkoxydim, . i.e. hydroxy-5—mesitylcyclohexen-l—one; c) difenzoquat, i.e. 1,2-dimethyl-3,S-diphenyl- pyrazolium salts; d) imazamethabenz, i.e. a mixture of 6-(4—isopropyl methyl-5—oxoimidazolin-2—yl)methyl—benzoic acid and —4—methyl-benzoic acid or their methyl esters; e) flamprop or flamprop-methyl, i.e. N-benzoyl-N-(3- chlorofluorophenyl)—alanine, or its methyl ester; ‘ fluoropyridin—2-yloxy)-phenoxy]—propionate.

The last—mentioned compounds a) to e) are likewise des- cribed in "The Pesticide Manual" (see above).

CGA—184927 is known from EP—A-191,736 and Brighton Crop Protection Conference - Weeds — 1989.

Surprisingly, it has emerged that, when amidosulfuron and the active compound B are used jointly, super- additive (= synergistic) effects were observed. The _ 3 _ activity in the combinations exceeded the activity of These effects allow the rate of application to be reduced, a the individual products employed when used alone. larger spectrum of broad-leaf and grass weeds to be controlled, more rapid action, an extended long-term action, complete control of the harmful plants with only one or few applications, and an extended interval during which the combination. These properties are required in practical active compounds may be applied in weed control in order to keep agricultural crops free from undesired competing plants and thus to guarantee, and/or to increase, the yields in terms of quality and quantity. These novel combinations markedly exceed the prior art with a view to the above—described properties.

The choice of the ratio by weight and the applications rates are a function of, for example, the other com- ponent in the mixture, the development stage of the broad-leaf weeds or grass weeds, the weed spectrum, environmental factors and climatic conditions.

The ratios by weight A:B of the combined herbicides can therefore vary within wide 1:200 to 20:1. limits and are generally The following ratios by weight are preferably used: In the case of combinations of the compounds of the formula (I) or salts thereof V 1:200 to 5:1, 1:50 to 2:1; — with diflufenican: preferably The application rates of the herbicide A in the active substance combinations 100 g of a.i./ha (a.i. = The application rates of compound B in the mixtures are are preferably between 5 and relative to active ingredient). generally from 5 to 1000 g of a.i./ha, preferably - with diflufenican 20 to 1000 g of a.i./ha, The substance combinations according to the invention can exist as mixed formulations of the two active components which are then applied in the customary the fornx of a dilution. with water, or are manner in A prepared in the form of so—called tank mixes by jointly diluting the separately formulated components with water .

The A type and B type compounds or their combinations can be formulated in many ways, depending on the prevailing biological and/or chemicophysical parameters.

The following are possible exemplary formulations: wettable powders (WP), emulsifiable concentrates (EC), aqueous solutions (SL), emulsions (EW) such as oil—in- water and water—in-oil emulsions, sprayable solutions or emulsions, oil- or water-based dispersions, suspo— emulsions, dusting jpowders (DP), seed-dressing agents, granules for soil application or for broadcasting, or water-dispersible granules (WG), ULV formulations, microcapsules or waxes.

The individual formulation types are known in principle and are described, for example, in: Winnacker-Kfichler, "Chemische Technologie Volume 7, [Chemical Technology]", C. Hauser Verlag Munich, 4th Ed. 1986; van Valkenburg, "Pesticides Formulations", Marcel Dekker N.Y., I973; K. Martens, "Spray Drying Handbook", 3rd Ed. 1979, G. Goodwin Ltd. London.

The formulation auxiliaries required such as inert materials, surfactants, solvents and other additives are equally known and are described, for example, in: "Handbook of Insecticide Dust Diluents Carriers", 2nd Ed., Darland Caldwell N.J.; H.v. Olphen, "Introduction. to Clay’ Colloid. Chemistry"; 2nd Ed., J. Wiley & N.Y.

Guide", 2nd Ed., N.Y.

"Detergents and Emulsifiers Annual", Watkins, and Books, Marsden, "Solvents 1950; MC Publ. Corp., Sons, Interscience, McCutcheon's, - _ 10 _ Ridegewood N.J.; Sisley and Wood, "Encyclopedia of Surface Active Egents", Chem. Publ. Co. N.Y. 1964; Schonfeldt, Athylenoxidaddukte [Surface—active Ethylene Oxide Adducts]", Wiss. Verlags- Stuttgart 1976, "Chemische Technologie_[Chemical Technology]", Volume 7, C. Hauser Verlag Munich, 4th Ed. 1986.

Inc., "Grenzfléchenaktive gesellschaft, Winnacker—Kfichler, Based on these formulations, it is also possible to prepare combinations with other pesticidally active substances such as other herbicides, fungicides or insecticides, as well as safeners, fertilizers and/or growth regulators, for example in the form of a finished formulation or a tank mix.

Wettable powders are preparations which can be dispersed uniformly in water and which comprise, beside the active substance, ionic or non-ionic surfactants (wetting agents, dispersants), for example polyoxethylated alkyl- phenols, polyethoxylated fatty alcohols or fatty amines, fatty alcohol polyglycol ether sulfates, alkane- sulfonates or Valkylbenzenesulfonates, sodium lignin- sulfonate, sodium 2,2‘-dinaphthylmethane—6,6'— disulfonate, sodium dibutylnaphthalenesulfonate or else sodium oleoylmethyltaurinate, besides a diluent or inert substance.

Emulsifiable concentrates are prepared by dissolving the active substance in an organic solvent, for example cyclohexanone, dimethylformamide, xylene, or with the addition of one or more ionic or non—ionic surfactants butanol, else higher-boiling aromatics or hydrocarbons, (emulsifiers). The following are examples of emulsifiers which can be used: calcium alkylarylsulfonates such as calcium dodecylbenzenesulfonate, or non—ionic emulsifiers such as fatty acid polyglycol esters, alkylaryl polyglycol ethers, fatty alcohol polyglycol ethers, propylene oxide/ethylene oxide condensation products, alkyl polyethers, sorbitan fatty acid esters, V _ 11 - polyoxyethylene sorbitan fatty acid esters or polyoxethylene sorbitol esters.

Dusting powders are obtained by grinding, the active substance with finely divided solid substances, for example talc, natural clays such as kaolin, bentonite and pyrophyllite, or diatomaceous earth.

Granules can be prepared either by spraying the active substance onto adsorptive, granulated inert material or by applying active substance concentrates to the surface of carrier substances such as sand, kaolinites or granu- lated inert material with the aid of adhesives, for example polyvinyl alcohol, sodium polyacrylate or else mineral oils. Suitable active substances can also be granulated in the fashion customary for the preparation of fertilizer granules, if desired in the form of a Water—dispersible granules are spray-drying, disk granulation, mixture with fertilizers. generally prepared by methods such as fluidized-bed granulation, mixing with high—speed mixers and extrusion without solid inert material.

As a rule, the agrochemical preparations comprise 0.1 to 99 percent by weight, in particular 2 to 95 % by weight, of active substances of types A + B. The concentrations of the .active substances A + B can differ in- the formulations.

For example, the active substance concentration in wettable powders is approximately 10 to 95 % by weight, the remainder to 100 % by weight is composed of customary formulation components. In the case of emulsifiable concentrates, the active substance concentration can be approximately 1 to 85 % by weight, preferably 5 to 80 % by weight. Formulations in the form of dusts comprise approximately’ 1 to 25 % by’ weight, substance, usually 5 to 20 % by weight, of active sprayable solutions approximately 0.2 to 25 % by weight, ‘ preferably 2 to 20 % by weight, of active substance. In the active substance content depends partly on whether the solid which fillers The content in the case of the water-dispersible granules is the case of granules such as dispersible granules, active compound is liquid or and on granulation auxiliaries and are used. generally between 10 and 90 % by weight. substance formulations mentioned the emulsifiers, the active comprise Besides, optionally adhesives, wetting agents, dispersants, penetrants, preservatives, antifreeze agents and solvents, fillers, colorants and carriers, defoamers, evaporation inhibitors, pH regu- lators and viscosity regulators which are customary in each case.

For‘ use, the formulations which exist in. commercially available form are optionally diluted in the customary manner, for example using water in the case of wettable powders, emulsifiable concentrates, dispersions and water-dispersible granules. Preparations in the form of dusts, granules_for soil application or for broadcasting as well as sprayable solutions are customarily not diluted further with application. other inert substances before The active substances can be applied to the plants, parts of the plants, seeds of the plants or the area under cultivation.

The active substances are preferably applied jointly in the form of tank mixes, the optimally formulated con- centrated formulations of the single active substances being mixed concomitantly with water in the tank, and the spray mixture obtained is applied.

The examples which follow are intended to illustrate the invention: ‘ A. a) -13..

Formulation examples A dusting agent is obtained by mixing 10 parts by weight of an active substance combination according to the invention and 90 parts by weight of talc as inert substance and. comminuting the mixture in. a hammer mill.

A wettable powder which is readily dispersible in water is obtained by mixing 25 parts by weight of active substances A + B, 64 parts by weight of kaolin—containing quartz as inert substance, parts by weight of potassium ligninsulfonate and 1 part by weight of sodium oleoylmethyltaurate as and dispersing agent, . wetting and grinding the mixture in a pinned disk mill.

A dispersion concentrate which is readily disper- sible in water is obtained by mixing 20 parts by weight of active substances A + B with 6 parts by weight of alkylphenol polyglycol ether (°Triton X 207) , glycol parts by’ weight of isotridecanol poly- (8 E0) paraffinic mineral oil 255 to 277°C), a ball mill to a fineness of below 5 microns. ether and 71 parts by weight of (boiling range, for example, approx. and grinding the mixture in An enmlsifiable concentrate is obtained .from parts by weight of cyclohexanone _as solvent and 10 parts by weight of oxethylated nony- lphenol as emulsifier.

Water—dispersible granules are obtained by mixing 75 parts by weight of active substances A + B, parts by weight of calcium ligninsulfonate, parts by weight of sodium lauryl sulfate, 3 parts by weight of polyvinyl alcohol and 7 parts,by weight of kaolin, ‘ _ 14 _ grinding the mixture on a pinned disk mill and granulating the powder in a fluidized bed by spray- ing on water as granulation liquid. f) Alternatively, water-dispersible granules are obtained by homogenizing and precomminuting parts by weight of active substances A + B, parts by weight of sodium 2,2‘-dinaphthyl— methane~6,6'-disulfonate, 2 parts by weight of sodium oleoylmethyltaurate, 1 part by weight of polyvinyl alcohol, 17 parts by weight of calcium carbonate and 50 parts by weight of water colloid mill, mixture on a bead null, on a subsequently grinding the and atomizing and drying the resulting suspension in a spray tower by means of a single-substance nozzle.

B. Biological examples broad—leaf grass weeds had grown under natural field conditions Various economically important weeds and (field trials). The herbicide mixtures were applied in the 2- harmful plants by’ means of plot spray equipment. to 5-leaf stage of the crop plants and the The water application rate was 300 - 400 liters of water per hectare.

Within 4 weeks after the application, the herbicidal activity of the treated plots was assessed by comparison The plant with untreated control plots by visual scoring. herbicidal the" growth and chlorotic and necrotic effects up to the total the qualitatively and quantitatively action as regards influencing destruction of weeds was assessed and indicated as percentage action (0 — 100 %).

Examples show that only high dosage rates of the single active substances allow good control of individual substances allow good effects to be achieved on all test individual the control level required is achieved by markedly lower weed species. The additive action of the components was markedly exceeded (synergism), i.e. application rates. These effects broaden the spectrum of action.

The crop tolerance, assessed in the form of damage, is not adversely affected, i.e. the combinations can be judged as fully selective.

Claims (1)

1. Patent claims A herbicidal composition which comprises A) a compound of the formula I or salts thereof OCH . 3 R — OCH, in combination with B) diflufenican, in a synergistically active amount. which compounds A composition as claimed in claim 1, additionally comprises one or more selected from the group consisting of growth- regulator—type herbicides, and also dicamba and salts thereof, nitrodiphenyl ethers, sulfonylureas (I), and salts thereof, and selective grass herbicides. which differ from the urea of the formula A composition as claimed in claim 2, wherein.the growth—regulator-type herbicides are selected from 2,44D, also the group consisting of MCPB, 2,4-DB, MCPA, and nitrodiphenyl ethers from the group consisting of mecoprop, dichlorprop and lactofen and fomesafen, acifluorfen, oxyfluorfen, and also sulfonylureas from the group consisting of triasulfuorn, chlorsulfuron, tribenuron, tribenuron-methyl, thifensulfuron, thifensulfuron- methyl, nicosulfuron, pirimisulfuron, pirimisul- furon—methyl, DPX—E 9636 and pyridylsulfonylureas, and also grass herbicides from the group consisting of diclofop, diclofop—methyl, tralkoxydim, difenzoquat, imazamethabenz, flamprop, flamprop-methyl and CGA-184927. A composition as claimed in one of the preceding claims, which comprises the compound (I) or salts thereof and the compound B in a ratio by weight of 1:200 to 20:1. A composition as claimed in one of the preceding claims, which comprises, besides the active substances of type A or B, customary formulation auxiliaries. A process for the preparation of a synergistically active composition as claimed in one or more of claims 1 to 5, which comprises formulating the compound of the formula (I) or salts thereof with the B type compound analogously to a customary crop protection agent formulation selected from the group consisting of wettable powders, emulsifiable concentrates, aqueous solutions, emulsions, sprayable solutions (tank mix), oil— or water-based dispersions, suspoemulsions, dusting powders, seed-dressing agents, granules for soil application or for broadcasting, water-dispersible granules, ULV formulations, microcapsules and waxe S . A method of controlling undesired plants, which comprises applying a herbicidally effective amount of a combination. of active substances A -+ B as defined in one or more of claims 1 to 5, to these plants or to the area under cultivation. The method as claimed in claim 7, wherein the application rates of the compounds of the formula (I) or salts thereof are from 5 to 100 g/ha and the application rates of the compound B are from 5 to 1000 g/ha. The method as claimed in claim 7 or 8, wherein the active substances of types A and B are applied in a ratio by weight of 1:200 to 20:1. The use of a synergistically active composition as defined controlling undesired plant growth. in one or more of claims 1 to 5 for The use as claimed in claim 10, —wherein harmful plants in crops of useful plants are controlled selectively. A composition as claimed in claim 1, substantially as hereinbefore described and exemplified. F. R. KELLY & CO., AGENTS FOR THE APPLICANTS.