WO2003047348A1

WO2003047348A1 - Herbicidal synergistic composition and method of weed control

Info

Publication number: WO2003047348A1
Application number: PCT/EP2002/013647
Authority: WO
Inventors: Cyrill Zagar; Jack A. Best; William B. O'neal; Dan E. Westberg; Andreas Landes; Winfried Mayer
Original assignee: Basf Aktiengesellschaft
Priority date: 2001-12-04
Filing date: 2002-12-03
Publication date: 2003-06-12
Also published as: AU2002358081A1; AR037701A1

Abstract

The invention relates to a herbicidal composition, comprising a compound formula I and a synergistically effective amount of an active ingredient of formula II.

Description

Herbicidal synergistic composition and method of weed control

Description

The present invention relates to a novel herbicidal synergistic composition that comprises a combination of herbicides suitable for selectively controlling weeds in crops of cultivated plants, typically in crops of cereals, maize, rice, rape, sugar beet, sugar cane, plantations, cotton and soybeans.

The invention further relates to a process for controlling weeds in crops of cultivated plants and to the use of said novel composition therefor.

The compound of formula I (common name dimethenamid-P)

has herbicidal activity, as is disclosed, inter alia, in US-A-5 457 085.

The following compound of formula II

is also known as herbicide (common name atrazine) , inter alia from "The Pesticide Manual" 10^th edition, p.51. Synergistic mixtures of the compound of formula II with the racemate of formula I are disclosed in EP 614 606.

Surprisingly, it has now been found that a variable amount of a combination of the active ingredient of formula I v/ith the active ingredient of formula II exerts a synergistic effect that is able to control the majority of weeds preferably occurring in crops of cultivated plants preemergence and/or postemergence, without substantial injury to the cultivated plants. Accordingly, this invention proposes a novel synergistic composition for selectively controlling weeds, which comprises as active ingredient on the one hand the compound of formula I

and, an the other hand, a synergistically effective amount of the active ingredient of formula II

H H in admixture with each other, provided that the compound 2-chlo- ro-N- (2 , 4-dimethyl-3-thienyl) -N- (2-methoxy-l-methylethyl) aceta- mide is not present in forum of its racemate.

The compound of formula I is the optical isomer (IS, aRS) -2-chlo- ro-N- (2 , 4-dimethyl-3-thienyl) -N- (2-methoxy-l-methylethyl) acet- amide .

It is highly surprising that the combination of the active ingre- dient of formula I with the active ingredient of formula II has a greater additive action against the weeds to be controlled than to be expected in principle and/or the selectivity to the cultivated plants is increased. Thus the activity range of both active ingredients is enhanced, in particular in two respects:

On the one hand, the rates of application of the single compounds I and II are reduced while the effectiveness of said compounds is retained. On the other hand, the novel combination also achieves a high degree of weed control where the single compounds have be- come no longer agriculturally effective at low rates of application. The consequence is a substantial broadening of the activity spectrum against weeds and an additional increase in the selectivity for the cultivated plants that is necessary and desirable in the event of unintentional overapplication of herbicide. Fur- thermore, the novel composition permits more flexibility in sub- sequent crops while retaining the excellent control of weeds in cultivated plants.

The novel herbicidal compostions can be used against a great num- ber of agriculturally important weeds, including Stellaria, Agrostis, Digitaria, Avena, Setaria, Sinapis, Lolium, Solanum, Echinochloa, Scirpus, Monochoria, Sagittaria, Eromus, Alopecurus, Sorghum halepense, Rottboellia, Cyperus, Abutilon, Sida, Xan- thium, Amaranthus , Chenopodium, Ipomoea, Chrysanthemum, Galium, Viola, Veronica, Ambrosia, Brachiaria, Bidens, Commelina, Polyg- onum, Panicum, Kochia, Sesbania, Eriochloa, Cassia and Euphorbia.

The novel compositions are suitable for all standard methods of application used in agriculture, typically preemergence applica- tion, postemergence application and seed dressing.

The novel herbicidal combination is preferably suitable for weed control in crops of cultivated plants, typically cereals, rape, sugar beet, sugar cane, plantations, rice, maize and soybeans as well as for non-selective weed control. The novel combination is preferably used in maize and soybeans.

Crops will be understood as meaning also those crops that have been made tolerant to herbicides or classes of herbicides by con- ventional breeding or genetic engineering methods.

The novel herbicidal combination contains the active ingredient of formula I and the active ingredient of formula II in any ratio, but usually with an excess of the one component over the other. Preferred ratios of the active ingredient of formula I and the component of formula II are in the range from 1:100 to 100:1, prefererably from 1:10 to 10:1, especially from 1:5 to 5:1.

The rate of application can vary over a wide range and will de- pend an the nature of the soil, the type of application (pre- or postemergence, seed dressing, application to the seed furrow; no tillage application etc.), the cultivated plant, the weed to be controlled, the respective prevailing climatic conditions; and an other factors governered by the type of application and the tar- get crop. The herbicidal combination can usually be applied in a rate of application of 0.05 to 5 kg, preferably of 0.5 to 4 kg/ha.

In addition to the compounds of formulae I and II, the novel com- positions can contain a safener. Examples for safeners are, inter alia, benoxacor, cloquintocet , cyometrinil, dichlormid, dicyclon, dietholate, fenchlorazole, fenclorim, flurazole, fluxofenim, furilazole, isoxadifen, mefen- pyr, mephenate, naphthaline anhydride, oxabetrinil and R 29148. Prefered safeners are for example benoxacor, cloquintocet, dichlormid, fenchlorazole, fenclorim, fluxofenim, furilazole, isoxadifen, mefenpyr or oxabetrinil.

The compounds of formula I and II are usually employed in unmodi- fied form, i.e. as obtained in the synthesis technical a.i.)

The purity of the technical a. i. of formula I is equal to 80 % or higher, preferably equal to 90 % or higher, especially equal to 95 % or higher.

In addition to the compounds of formulae I and II, the novel composition can contain a further herbicide (but not 2-chlo- ro-N- (2 , 4-dimethyl-3-thienyl) ) -N- (2-methoxy-l-methylethyl) aceta- mide in whichever form) . Suitable herbicides are for example, 1, 2 , 4-thiadiazoles, 1 , 3 , 4-thiadiazoles , amides, aminophosphoric acid and its derivatives, aminotriazoles, anilides, (het) aryloxy- alkanoic acids and their derivatives, benzoic acid and its derivatives, benzothiadiazinones, 2-aroyl-l , 3-cyclohexanediones , hetaryl aryl ketones, benzylisoxazolidinones , meta-CF₃-phenyl de- rivatives, carbamates, quinolinecarboxylic acid and its derivatives, chloroacetanilides, cyclohexenone oxime ethers, diazines, dichloropropionic acid and its derivatives, dihydrobenzofurans, dihydrofuran-3-ones, dinitroanilines, dinitrophenols , diphenyl ethers, dipyridyls, halocarboxylic acids and their derivatives, ureas, 3-phenyluracils , imidazoles, imidazolinones, N-phe- nyl-3 , 4 , 5, 6-tetrahydrophthalimides, oxadiazoles, oxiranes, phenols, aryloxy- and hetaryloxyphenoxypropionic esters, phenyla- cetic acid and its derivatives, 2-phenylpropionic acid and its derivatives, pyrazoles, phenylpyrazoles , pyridazines, pyridine- carboxylic acid and its derivatives, pyrimidyl ethers, sulfona- mides, sulfonylureas, triazines, triazinones, triazolinones, triazolecarboxamides and uracils.

Usually the combination of the compiound of formula I with the compound of formula II are processed in conventional manner with the assistants customarily employed in formulation technology, typically solvents, solid carriers or surfactants, e.g. to emul- sifiable concentrates, directly sprayable or dilutable solutions, suspensions, pastes, wettable powders, soluble powders, dusts, granulates or microcapsules . As with the type of compositions, the methods of application such as spraying, atomising, dusting, wetting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances. In any case the use form should guarantee the finest possible distribution of the active ingredients according to the invention.

The formulations, i.e. the compositions containing the active ingredients of formulae I and II and optionally one or more than one conventional inert formulation assistants, are prepared in per se known manner, e.g. by homogeneously mixing and/or grinding the active ingredient with said formulation assistants, typically solvents or solid carriers. Surface-active compounds (surfactants) may additionally be used for preparing the formulations.

Suitable solvents may typically be: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms such as mixtures of xylene 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, 2-methoxyeth- anol or 2-ethoxyethanol ; ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethylsulfoxide or N,N-dimethylformamide, as well as vegetable oils or epoxidised vegetable oils such as epoxidised coconut oil or soybean oil; or water .

The solid carriers typically used for dusts and dispersible powders are usually natural mineral fillers such as calcite, talcum, kaolin, montmorillonite or attapulgite. 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, including pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are materials such as calcite or sand. In addition, innumerable pregranulated materials of inorganic or organic origin may be used, especially dolomite or pulverised plant residue.

Suitable surface-active compounds are nonionic, cationic and/or anionic surfactants or mixtures of surfactants having good emulsifying, dispersing and wetting properties.

Suitable anionic surfactants may, be water-soluble soaps as well as water-soluble synthetic surface-active compounds .

Suitable soaps are the alkali metal salts, alkaline earth metal salts, ammonium salts or substituted ammonium salts of higher fatty acids (C10-C22), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures which can be obtained, inter alia, from coconut oil or tallow oil. Further suitable soaps are also the fatty acid methyl taurin salts.

More often, however, so-called synthetic surfactants are used, especially fatty sulfonates, fatty sulfates, sulfonated benzimi- dazole derivatives or alkylarylsulfonates .

The fatty alcohol sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts, ammonium salts or substituted ammonium salts, and they contain a C₈-C₂₂alkyl radical which also includes the alkyl moiety of acyl radicals, e.g. the sodium or calcium salt of ligninsulfonic acid, of dode- cylsulfate, 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 two sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms. Illustrative examples of alkylarylsulfonates are the sodium, calcium or triethanolamine salts of dodecylbenzene- sulfonic acid, dibutylnaphthalenesulfonic acid, or of a condensate of naphthalenesulfonic acid and formaldehyde.

Corresponding phosphates, typically salts of the phosphoric acid ester of p-nonylphenol- (4-14) ethylene oxide, or phospholipids , are also suitable.

Nonionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols or of saturated or unsat- urated 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 nonionic surfactants are alkyl glycoside, water- soluble polyadducts of poylethylene oxide with polypropylene glycol, ethylenediaminopolypropylene glycol and alkylpolypropylene glycol containing 1 to 10 carbon atoms in the alkyl chain, which polyadducts 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.

Illustrative examples of nonionic surfactants are nonylphenol polyethoxylates, polyethoxylated castor oil, polyadducts of polypropylene and polyethylene oxide, tributylphenol polyethoxylate, polyethylene glycol and octylphenol polyethoxylate. Fatty acid esters of polyoxyethylene sorbitan are also suitable nonionic surfactants, typically polyoxyethylene sorbitan trio- leate.

Cationic surfactants are preferably quaternary ammonium salts carrying, as N-substituent , at least one Cs-C₂₂alkyl 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, methyl sulfates or ethyl sul- fates, for example stearyl trimethylammonium chloride or benzyl bis (2-chloroethyl) ethylammonium bromide.

The surfactants customarily employed in the art of formulation are described, inter alia, in "Mc Cutcheon's Detergents and Emul- sifiers Annual" MC Publishing Corp., Ridgewood New Jersey, 1981, Stache, H., "Tensid-Taschenbuch" , Carl Hanser Verlag, Munchen/ Wien, 1981 and M. and J. Ash, "Encyclopedia of Surfactants", Vol I-III, Chemical Publishing Co., New. York, 1980-81.

Also the combinations of compound of formula I with the compound of formula II with a safener and/or a further herbicide (but not 2-chloro-N- (2 , 4-diethyl-3-thienyl) -N- (2-methoxy-l-methylethyl) acetamide in whichever form) are usually processed in conventional manner with the assistants customarily employed in formulation technology as above mentioned.

Preferably the combinations of the compound of formula I with the compound of formula II are processed in conventional manner with the asssistants customarily employed in formulation technology as above-mentioned.

Also preferably the combinations of the compounds of formula I with the compound of formula II with a safener are processed in conventional manner with the assistants customarily employed in formulation technology as above-mentioned.

Also preferably the combinations of compound of formula I with the compound of formula II with a further herbicide (but not 2-chloro-N- (2 , 4-diethyl-3-thienyl) -N- (2-methoxy-l-methyl- ethyl) acetamide in whichever form) are processed in conventional manner with the assistants customarily employed in formulation technology as above-mentioned.

The herbicidal formulations usually contain from 0.1 to 99 % by weight, preferably from 0.1 to 95 % by weight, of active ingredient mixture of the compound of formula I with the compound of formula II, from 1 to 99.9 % by weight of a solid or liquid for- mulation assistant, and from 0 to 25 % by weight, preferably from 0.1 to 25 % by weight, of a surfactant.

Whereas it is preferred to formulate commercial products as con- centrates, the end user will normally use dilute formulations.

The compositions may also contain further ingredients such as stabilisers, vegetable oils or epoxidised vegetable oils (epoxidised coconut oil, rape seed oil or soybean oil), antifoams, e.g. silicone oil, preservatives, viscosity regulators, binders, tack- ifiers, as well as fertilisers or other active ingredients.

Preferred formulations are those composed of: (% = percent by weight)

Emulsifiable concentrates: compound mixture: 1 to 90 %, preferably 5 to 20 % surfactant: 1 to 30 %, preferably 10 to 20 % liquid carrier: 5 to 94 %, preferably 70 to 85 %

Aqueous suspo-emulsion: compound mixture: 5 to 75 %, preferably 20 to 55 % water: 93 to 23 %, preferably 65 to 30 % organic solvent: 0 to 20 %, preferably 0 to 5 % surfactant: 1 to 30 %, preferably 3 to 15 %

The invention is illustrated by the following non-limitative Examples .

Formulation Examples for mixtures of herbicides of formulae I and II (% = percent by weight)

Fl . Emulsifiable concentrates a ) b) c ) d ; compound mixture 5 % 10 % 25 % 50 % calcium dodecylbenzenesulfonate 6 % 8 % 6 % 8 % polyethoxylated castor oil 4 % - 4 % 4 %

(36 mol EO) octylphenol polyethoxylate - 4 % - 2 %

(7-8 mol EO) cyclohexanone - - 10 % 20 % mixture of aromatic hydrocarbons C₉-C₁₂ 85 % 78 % 55 % 16 %

Emulsions of any desired concentration can be prepared by dilut- ing such concentrates with water. F2. Solutions a) b) c ) d) compound mixture 5 % 10 % 50 % 90 l-methoxy-3- (3-methoxy- propoxy) propane 20 % 20 % - polyethylene glycol MG 400 20 % 10 % - - N-methyl-2-pyrrolidone 30 % 10 mixture of aromatic hydrocarbons C₉-C₁₂ 75 % 60 %

The solutions are suitable for use as microdrops .

F3. Aqueous suspo-emulsions a) b) compound mixture 45 % 50 % ethylene glycol 5 % propylene glycol 3 % nonionic surfactant blend 2 % anionic/nonionic blend with CaDBS* - 2 % anionic/nonionic blend containing 6 % phosphate ester polymeric surfactant 1 % biocide 0 1 % 0.1 % thickener 2 % 0.3 % silicone oil emulsion 0.1 % 0.5 % organic solvent 3 % water 41 %

* CaDBS = calcium salt of dodecylbenzenesulphonate

The aqueous part is prepared by dispersing the active ingredients and a part of the surfactants in water. Subsequently the mixture is ground down to the desired particle site in a wet milling process. Then the oil phase is emulsified into the aqueous and the product finished by the addition of additional formulants.

It is often more expedient to formulate the active ingredient of formula I and the component of formula II individually and only to combine them shortly before application in the applicator in the desired mixture ratio as tank mixture in water.

Also it is possible to treat the cultivated plant or the locus thereof at seperate times with the compound of formula I and with the compound of formula II.

Also additional active ingredients like safeners of further her- bicides may be applied together or seperately with the comounds of formulae I and II. Biological Examples:

Example HI: The following test compares the action of a composition of this invention, comprising as active ingredients the en- antiomer (IS, aRS) -2-chloro-N- (2 , 4-dimethyl-3-thienyl) -N- (2-methoxy-l-methylethyl) acetamide of formula I

and the compound of formula II

CH₃

with a composition known from EP 614 606, comprising the racemic compound 2-chloro-N- (2 , 4-dimethyl-3-thienyl) -N- (2-methoxy-l-meth- ylethyl) acetamide of formula A

and the cited compound of formula II.

The mixtures according to the invention were applied pre- or post-emergence (foliar treatment) . The compounds of formula I and II were applied in the formulation in which they are present as commercially available product.

Some of the experiments were greenhouse experiments and some were field trials on mini plots (on a site with sandy loam (pH 6.2 to 7.0) or sandy clay (pH 5.0 to 6.7) as the soil). The harmful plants differed with regard to size and developmental state; on average, they were 5 to 20 cm long, depending on the growth habit.

The compounds of formula I and II were applied in succession or jointly, in the latter case in some cases as a tank mix and in some cases as a readymix, in the form of emulsions, aqueous solutions or suspensions, the vehicle being water (300 - 400 1/ha) . In the case of the field trials, application was effected with the aid of a mobile plot sprayer.

The test period extended over 3 to 8 weeks, and the stands were also observed at later points in time.

Damage by the herbicidal compositions was evaluated with reference to a scale of 0 % to 100 % in comparison with untreated control plots. 0 means no damage and 100 means complete destruction of the plants.

The following examples will demonstrate the action of the herbicidal compositions which can be used according to the invention, without excluding the possibility of other uses.

In these examples, the value E at which only an additive effect of the individual active ingredients is to be expected was calculated by the method of S. R. Colby (,Calculating synergistic and antagonistic responses of herbicide combinations", Weeds 15, 20 (1967) ) .

This was done may the formula

E = X + Y - XY 100

where

X= Percentage of the herbicidal action of component A) at an application rate of a;

Y= Percentage of the herbicidal action of component B) at an application rate of b;

E= expected herbicidal action of component A) + B) at rates of application a + b (in %) ; If the value observed exceeds the value E calculated in accordance with Colby's formula, then synergisum ist present.

The composition according to the invention exert a greater herbi- cidal action than would have been expected according to Colby on the basis of the observed effects of the individual components when used alone.

The results of the tests are shown in Tables 1 to 3

In these studies following plants where used:

Table 1 : Herbicidal action of componend I and of compound II on Alopecurus myosuroides (post emergence treatment)

Table 2 : Herbicidal action of componend I and of component II on Amaranthus retroflexus (post emergence treatment)

Table 3 : Herbicidal action of componend I and of component II on Brachiaria plantaginea (post emergence treatment)

Claims

We claim :

1. A herbicidal synergistic composition, comprising, a compound of formula I

and a synergistically effective amount of the active ingredient of formula II

2. A herbicidal composition according to claim 1, wherein the weight ratio of the component of formula I to the component of formula II is from 1 : 100 to 100 : 1.

3. A herbicidal synergistic mixture, comprising, besides conventional inert formulation assistants, an effective amount of a herbicidal synergistic compositions as claimed in any of claims 1 to 2.

4. A method of controlling undesirable plant growth in crops of cultivated plants, which comprises treating the cultivated plant or the locus thereof with a herbicidally effective amount of a composition as claimed in any of claims 1 or 2 , or with a mixture as claimed in claim 3.

5. A method according to claim 4, wherein the cultivated plants are cereals, rape, sugar beet, sugar cane, plantations, rice, maize or soybeans.

6. A method according to claim 4, which comprises treating the crops of cultivated plants with the claimed composition in rates of application corresponding to 0.05 to 5 kg of total amount of active ingredient per hectare.

7. A composition according to claim 1 or a mixture according to claim 3, comprising, in addition to the compounds of formulae I and II, a safener.

8. A method according to claim 4, which comprises treating the cultivated plant or the locus thereof simultaneusly with the compound of formula I and with the compound of formula II.

9. A method according to claim 4, which comprises treating the cultivated plant or the locus thereof at separate times with the compound of formula I and with the compound of formula II.