CA2055886A1

CA2055886A1 - Synergistic composition, and method for selective control of weeds

Info

Publication number: CA2055886A1
Application number: CA 2055886
Authority: CA
Inventors: Wolfgang P. Iwanzik; Hans Gut; Marco Quadranti
Original assignee: Individual
Current assignee: Novartis AG
Priority date: 1990-11-22
Filing date: 1991-11-20
Publication date: 1992-05-23
Also published as: EP0487454A2; EP0487454A3; BR9105063A; JPH0592904A

Abstract

Synergistic composition, and method for selective control of weeds Abstract:
Herbicidal composition containing a compound of the formula I

(I) and a synergistically active amount either of an active substance of the formula II

(II) or of an active substance of the formula III

(III) or of an active substance of the formula IV

(IV) or of an active substance of the formula V:

(V) or of an active substance of the formula VI:

(VI) or of an active substance of the formula VII:
[CH3(CH2)2]2NCOSCH2CH3 (VII) or of an active substance of the formula VIII:

(VIII) or of an active substance of the formula IX:

(IX) or of an active substance of the formula X:

(X) or of an active substance of the formula XI:

(XI) or of an active substance of the formula XII:

(XII) or of an active substance of the formula XIII:

(XIII) or of an active substance of the formula XIV:

(XIV) or of an active substance of the formula XV:

(XV) or of an active substance of the formula XVI

(XVI) or of an active substance of the formula XVII

Description

2~8~ ~

PEVS- 1 843~/A

Syner~eistic composition. and med~od ror selective control of weeds The present invention relates to a synergistic composition which contains a herbicidal active subs~ance combination and which is outstandingly suitable for selective weed control in crops of useful plants, in paIticular in soya, sugar beet, oilseed rape, cotton and vegetable crops.

The invention also relates to a method of controlling weeds in crops of useful plants, preferably in soya, sugar beet, oilseed rape, cotton and vegetable crops, and to the use of this novel composition.

S-(1-Methylthiocyclopropan-1-yl)-2-[1-(trans-3-chloroallyloximino)-propionyl]-cyclo-hexane-1,3-dione of the formula I
~cl ~

,o ~cH2cH3 (I) V<~

has proved an outstanding selective herbicide against weeds in crops of useful plants. This active substance and its preparation and use has been described in European Patent Specification EP-A-0243313.

The compounds of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI and XVII are also known as selective herbicides. They are commercially available.
These compounds have the following structures:

~_ COCH2CI

Compound of the formula II:
2-Chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide (alachlor), known from Pesticide Manual, 8d' Ed. (1987), page 5, The British Crop Protection Council, London;

~ 2 (III) Compound of the formula III:

3-Isopropyl-l-H-benzo-2,1,3-thiadiazin-4-one 2,2-dioxide (bentazon), known from Pesticide Manual, 8d' Ed. (1987), page 63, The British Crop Protection Council, London;

H2N ~ ~ (IV) Compound of the formula IV:
5-Amino-4-chloro-2-phenylpyridazin-3(2H)-one (chloridazon), known from PesticideManual, 8th Ed. (1987), page 155, The 13ritish Crop Protection Council, London;

Cl~ O ~H N 1 N ~ C ~l (V) 2 ~

Compound of the formula V:
3-[4-(4-Chlorophenoxy)phenyl]-N,N-dimethylurea (chloroxuron), known from Pesticide Manual, 8'h Ed. (1987), page 174, The British Crop Protection Council, London;

I(cH3)2cHl2NcoscH Cl cZ~<cl (VI) Compound of the formula VI:
S-(2,3,3-Trichloroallyl) diisopropylthiocarbamate (tri-allate), known from Pesticide Manual, 8~ Ed. (1987), page 816, The British Crop Protection Council, London;

[CH3(CH2)2]2NCOSCH2CH3 (VIl) Compound of the formula VII:
S-Ethyl dipropylthiocarbamate (EPTC), known from Pesticide Manual, 8~ Ed. (1987), page 341, The British Crop Protection Council, London;

~,_ CH
CH3 (VIII) ~F3 Compound of the formula VIII:
N,N,-Dimethyl-N'-[3-(trifluoromethyl)phenyl]-urea (fluometuron), known from Pesticide Manual, 8th Ed. (1987), page 412, The British Crop Protection Council, London;

CF~o~} 7H3 o ;. ~ ' . ~'';. ' ' 2~8~

Compound of the formula IX:
(RS)-2-[4-(3-Chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]-propionic acid (haloxyfop), known from Pesticide Manual, 8th Ed. (1987), page 453, The British Crop Protection Council, London;

CH~ CH3 N~
~N~C_NH (X) CH~\COOH

Compound of the forrnula X:
(RS)-5-Ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid (imazethapyr), known from Pesticide Manual, 8~ Ed. (1987), page 475, The British Crop Protection Council, London;

~ / OCH2CI (XI) CH3 ~

Compound of the formula XI:
2-Chloro-N-(2,6-dimethylphenyl)-N-(lH-pyrazol-l-ylmethyl)-acetamide (metazachlor), known from Pesticide Manual, 8'h Ed. (1987), page 537, The British Crop Protection Council, London;

~ / OCH2Cl (XII) CH3 CH(CH3)CH20cH3 - - -2 ~

Compound of the formula XII:
2-Chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy- 1 -methylethyl)-acetamide (metolachlor), known from Pesticide Manual, 8th Ed. (1987), page 568, The British Crop Protection Council, London;

N--N
(CH3)3-C~ SCH (XIII) O NHz Compound of the formula XIII:
4-Amino-6-tert-butyl-3-methylthio-1,2,4-triazin-5-one (metribuzin), known from Pesticide Manual, 8d' Ed. (1987), page 573, The British Crop Protection Council, London;

~ NH--C(~ (XIV) Compound of the formu1a XIV:
Methyl 3-(3-methylcarbaniloyloxy)-carbanilate (phenmedipham), known from Pesticide Manual, 8~ Ed. (1987), page 652, The British Crop Protection Council, London;

~OCH2CH3 ~CH2CH2CH3 (XV) S~

Compound of the formula XV:

:
, 2~88~

(+)-(ZE)-2-( 1 -Ethoxyiminobutyl)-5-[2-(ethylthio)propyl] -3-hydroxycyclohex-2-enone (sethoxydim), known from Pesticide Manual, 8'h Ed. (1987), page 744, The British Crop Protection Council, London;

~CH2CH2CH3 CF~ N~ (XVI) Compound of the formula XVI:
2,6-Dinitro-N,N-dipropyl-4-trifluoromethylaniline (trifluralin), known from Pesticide Manual, 8d` Ed. (1987), page 744, The British Crop Protection Council, London;

~ ~ (XVII) Compound of the formula XVlI:
2-Chloro-N-[2,6-dinitro-4-trifluoromethyl)phenyl] -N-ethyl-6-fluorobenzenemethanamine (flumetralin), known from Pesticide Manual, 8~ Ed. (1987), page 411, The British Crop Protection Council, London.

Surprisingly, it has now emerged that a combination of two active substances, on the one hand the active substance of the formula I and on the other hand an active substance of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII, where the amount of these active substances may vary, has a synergistic effect which allows most of the weeds which occur in crops of useful plants to be controlled both pre-emergence and post-emergence without causing damage to the useful plant.

There is therefore proposed according to the present invention a novel synergistic '` '' ~ . :

2 ~ 8 ~ ~

composition for selective weed control which contains, as active substance, on the one hand S-(1-methylthiocyclopropan-1-yl)-2-[1-(trans-3-chloroallyloximino)-propionyl]-cyclohexane-1,3-dione of the forrnula I
~cl ,o O N (I) ~CH2CH3 ~

and on the other hand a synergistically active amolmt either of an active substance of the forrnula II

CH20CH, or of an active substance of the formula ~I

1~ ~ (111) or of an active substance of the formula IV

H2N ~ ~ (IV) - 8 - 2 ~

or of an active substance of the folmula V:

CI~O~HN 1N~CH (V) or of an active substance of the forrnula VI:

KcH3)2cHl2NcoscHz>=<cl (VI) cl cl or of an active substance of the formula VII:
[CH3(CH2)2]2NCOSCH2CH3 (VII) or of an active substance of the formula VIII:

~HN 11 N~ 3 ~CH3 (VIII) C~F3 or of an active substance of the forrnula l:X:

CF~ O ~ I H3 or of an active substance of the formula X:

.
.

:

2~5~8~
_ 9_ CH~$

~N ~ NH (X) CH~\COOH

or of an active substance of the formula XI:

~ ~COCH2CI
(XI) --~ N--N
CH3 l~

or of an active substance of the forrnula XII:

(XII) CH3 CH(CH3)CH20CH3 or of an active substance of the formula XIII:

N--N
(CH3)3c~ SCH (XI~I) \N~12 or of an active substance of the forrnula XIV:

2 ~

HN--COOCHa NH--C~ (XIV) c or of an active substance of the formula XV:

~OCH2CH3 ~CH2CH2CH3 (XV) S~OH

or of an active substance of the formula XVI
.

fi~ ~CH2CH2CH3 CF--</ \7--N~ (XVI) ~=~ CH2CH2CH3 or of an active substance of the formula XVI~

~2 ~ (XVII) 2 ~ 8 ~

as a mixture with each other.

It is highly surprising that the combination of the active substance of the formula I with an active substance of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI and XVII not only causes an additive broadening of the spectrum of acdon on the weeds to be controlled, which would have been expected in principle, but that it achieves a synergisdc effect which broadens the limitations of the actions of the two preparations with regard to two aspects:

On the one hand, the application rates of the individual compounds I and II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI and XVII are reduced while maintaining an equally good action. On the other hand, the combined mixture still achieves a high degree of weed control even in areas where both individual active substances have lost their action completely in the range of excessively low application rates. This entails a substantial broadening of the weed spectrum and an additional increase in the safety margin on the crops of useful plants, as is necessary and desirable for an unintentional overdose with active substance.

The active substance combination according to the invention contains one active substance of the formula I and one active substance of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII in any desired mixing ratio, generally with an excess of one over the other component. Preferred mixing ratios between the active substance of the formula I and the components in the mixture of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII are between 1: 1000 and 1: 1, in particular between 1: 500 and 1: 5.

Combinations of the compound of the formula I with the compounds of the forrnulae III, VI, VIII, XII, XIII and XIV have proved to be very particularly effective synergistic active substance mixtures.

The herbicidal active substance combination according to the invention is outstandingly suitable for selectively controlling weeds in crops of useful plants, in particular in crops of soya, sugar beet, oilseed rape, cotton and vegetables. A particularly outstanding effectiveness against weeds was found in crops of oilseed rape, cotton, soya and sugar ~. .
--. . .

2 ~ 8 ~

beet.

Using the herbicidal active substance combination according to the invention, a large number of agronomically important weeds such as, for example, Digitaria sanguinalis, Sorghum halepense, Alopecurus myosuroides, Setaria faberi or Echinochloa crus galli, can be controlled pre-emergence and post-emergence.

The application rate can vary within wide ranges and depends on the nature of the soil, the type of application (pre- or post-emergence; seed treatment; furrow treatment; no-tillage application etc.), on the crop plant, on the weed to be controlled, on the prevailing climatic conditions in each case, and other factors determined by type of application, timing and target crop. In general, the acdve substance mixture according to the invention can be used at an application rate of 10 to 2000 [g of active ingredient/ha], in particular 30 to 1000 [g of active ingredient/ha].

The mixtures of the compound of the formula I with the compounds of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII are employed in unaltered form, as obtained from the synthesis, or, preferably, with the adjuvants customary in the art of formulation, and they are therefore processed in a known manner to give, for example, emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules and also encapsulations, for example in polymeric substances. The application methods such as spraying, misting, atomising, wetting, broadcasting or pouring, as well as the nature of the compositions, are selected to suit the intended aims and the prevailing circumstances.

The formulations, i.e. the compositions, preparations or products containing the active substances of the formulae I and II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII, as well as, if appropriate, one or more solid or liquid additives, are prepared in a known manner, for example by intimately mixing and/or grinding the active substances with extenders, for example with solvents, solid carriers and, if appropriate, surface-active compounds (surfactants).

The following are possible as solvents: aromatic hydrocarbons, in particular the fractions C8 to Cl2, such as mixtures of alkylbenzenes, for example xylene mixtures or alkylated naphthalenes; aliphadc and cycloaliphatic hydrocarbons such as paraffins, cyclohexane or tetrahydronaphthalene; alcohols such as ethanol, propanol or butanol; glycols as well as 2~5~8~

their ethers and esters, such as propylene glycol or dipropylene glycol ether, ketones such as cyclohexanone, isophorone or diacetone alcohol, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or water; vegetable oils as well as their esters such as rapeseed oil, castor oil or soya oil; if appropriate also silicone oils.
Solid carriers which are generally used, for example for dusts and dispersible powders, are ground natural minerals such as calcite, talc, kaolin, montmorillonite or attapulgite. To improve the physical properties, it is also possible to add highly-disperse silicas or highly-disperse absorptive polymers. Possible particulate, adsorptive carriers for granules are either porous types such as pumice, crushed brick, sepiolite or bentonite, and also non-sorptive carrier materials such as calcite or sand. Moreover, a large number of pregranulated materials of inorganic or organic origin can be used, such as, in particular, dolomite or comminuted plant residues.

Suitable surface-active compounds are non-ionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties, depending on the nature of the active substance of the formula I to be formulated. Surfactants are also to be understood as meaning mixtures of surfactants.

Anionic surfactants which are suitable can be either so-called water-soluble soaps or water-soluble synthetic surface-active compounds.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or substituted or unsubstituted ammonium salts of higher fatty acids (C1O-C22), such as the sodium salts or potassium salts of oleic or stearic acid, or of natural mixtures of the fatty acids which can be obtained, for example, from coconut or tallow oil. Mention must also be made of the fatty acid methyltaurinates.

However, so-called synthetic surfactants are used more frequently, in particular fatty alcohol sulfonates, fatty alcohol sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates .

The fatty alcohol sulfonates or fatty alcohol sulfates are generally in the form of alkali metal salts, alkaline earth metal salts or substituted or unsubstituted ammonium salts and have an alkyl radical with 8 to 22 C atoms, alkyl also including the alkyl moiety of acyl radicals, for example the sodium salt or calcium salt of lignin sulfonic acid, of 2 ~ 6 dodecylsulfuric ester or of a fatty alcohol sulfate mixture which has been prepared from natural fatty acids. This group also includes the salts of the sulfuric esters and sulfonic acids of fatty alcohoVethylene oxide adducts. The sulfonated benzirnidazole derivatives preferably contain 2 sulfonyl groups and one fatty acid radical with 8-22 C atoms.
Examples of aL~cylarylsulfonates are the sodium, calcium or triethanol amine salts of dodecylbenzenesulfonic acid, or dibutylnaphthalenesulfonic acid, or of a naphthalenesulfonic acid/formaldehyde condensation product.

Other suitable compounds are the corresponding phosphates, for example the salts of the phosphoric ester of a p-nonylphenoV(4-14)-ethylene oxide adduct, or phospholipids.

Suitable non-ionic surfactants are mainly polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, of saturated or unsaturated fatty acids and of alkylphenols which can contain 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon radical and 6 to 18 carbon atoms in the alkyl radical of the alkyl phenols.

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

Examples of non-ionic surfactants which may be mentioned are nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol .

Other suitable substances are fatty acid esters of polyoxyethylenesorbitan, such as polyoxyethylenesorbitan trioleate.

The cationic surfactants are mainly quaternary ammonium salts, which contain at least one alkyl radical having 8 to 22 C atoms as N-substituent and which have lower halogenated or free alkyl, benzyl or lower hydroxyalkyl radicals as further substituents. The salts are preferably in the form of halides, methyl sulfates or ethyl sulfates, for example stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

. .

, ~ . . , 2 ~
- ls -The surfactants customary in the art of formulation are described, inter alia, in the following publications:

- "Mc Cutcheon's Detergents and Emulsifiers Annual", Mc Publishing Corp., Glen Rock, New Jersey, 1988.
- M. and J. Ash, "Encyclopedia of Surfactants", Vol. I-m, Chemical Publishing Co., New York, 1980-1981.
- Dr. Helmut Stache "Tensid-Taschenbuch" [Surfactants Guide], Carl Hanser Verlag, Munich/Vienna 1981.

As a rule, the pesticidal preparations contain 0,1 to 99 %, in particular 0,1 to 95 %, of active substance mixture of the formula I with the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII, 1 to 99 % of a solid or liquid additive and 0 to 25 %, in particular 0.1 to 25 %, of a surfactant.

While concentrated compositions are often preferred as commercial products, the consumer generally uses dilute compositions.

The compositions can also contain further additives such as stabilisers, for example epoxidised or non-epoxidised vegetable oils (epoxidised coconut oil, rapeseed oil or soya oil), defoamers such as silicone oi1, preservatives, viscosity regulators, binders, tackifiers as well as fertilisers or other active substances for achieving specific effects.

In particular, preferred formulations have the following composition: (% = percent by weight) Emulsif1able concentrates:
Active compound mixture: 1 to 90 %, preferably 5 to 20 %
surface-active agent: 1 to 30 %, preferably 10 to 20 %
liquid carrier: 5 to 94 %, preferably 70 to 85 %

Dusts:
Active compound mixture: 0.1 to 10 %, preferably 0.1 to 1 %
solid carrier: 99.9 to 90 %, preferably 99.9 to 99 %

21~8~

Suspension concentrates:
Active compound mixture: S to 75 %, preferably 10 to 50 %
water:94 to 24 %, preferably 88 to 30 %
surface-active agent:1 to 40 %, preferably 2 to 30 %

Wettable powders:
Active compound mixture: 0.5 to 90 %, preferably 1 to 80 %
surface-active agent:0.5 to 20 %, preferably 1 to 15 %
solid ca~ier material: S to 95 %, preferably 15 to 90 %

Granules:
Active compound mixture: 0.5 to 30 %, preferably 3 to 15 %
solid carrier:99.5 to 70 %, preferably 97 to 85 %

F1. Formulation examples Mixtures of the compounds of the formulae I and II. III~ IV. V. VI. VI[, VIII. IX. X, XIL
XIII, XIV, XV, XVI or XVII (% = percent by wei~ht) a) Wettable powders a) b) c) d) Mixture of active substance of the formula I with one of the active substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII 10 % 20 % 5 % 30 %
Sodium ligninsulfonate 5 % 5 % 5 % 5 %
Sodium lauryl sulfate 3 % - 3 %
Sodium diisobutylnaphthalene-sulfonate - 6 % - 6 %
Octylphenol polyethylene glycol ether (7-8 mol of EO) - 2 % _ 2 %
Highly disperse silica 5 % 27 % 5 % 27 %
Kaolin 67 % - 67 %

The active substance mixture is mixed thoroughly with the additives and the mixture is 20~8~6 ground thoroughly in a suitable mill. This gives wettable powder which can be diluted with water to give suspensions of any desired concentration.
b) Emulsion concentrate a) b) c) Mixture of active substance of the formula I with one of the active substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII 5 % 5 % 12 %
Octylphenol polyethylene glycol ether (4-5 mol of EO) 3 % 3 % 3 %
Calcium-dodecylbenzenesulfonate 3 % 3 % 2 %
Castor oil polyglycol ether (36 mol of EO) 4 % 4 % 4 %
Cyclohexanone 30 % 30 % 31 %
Xylene mixture 50 % 35 % 35 %

Emulsions of any desired concentration can be prepared from these concentrates by dilution with water.
c)Dusts a) b) c) d) Mixture of active substance of the formula I with one of the active substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII 2 % 4 % 2 % 4 %
Talc 3 % 4 % 4 % 8 %
Kaolin 95 % 92 % 94 % 88 %

Ready-for-use dusts are obtained by mixing the active substance mixture with the carrier and gr~nding the mixture on a suitable mill.

.~

, . . .

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d) Extruder granules a) b) c) Mixture of active substance of the formula I with one of the active substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII5 % 3 % 5 %
Sodium ligninsulfonate2 % 2 % 2 %
Carboxymethylcellulose1 % 1 % 1 %
Kaolin 87 % 87 % 77 %

The active substance mixture is mixed with the additives, and the mixture is ground and moistened with water. This mixture is extruded and subsequently dried in a stream of air.
e) Coated granules a) b) Mixture of active substance of the formula I with one of the active substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII 1.5 % 3 %
Polyethylene glycol (MW 200) 3 % 3 %
Kaolin -- 94 % 89 %

In a mixer, the kaolin which has been moistened with polyethylene glycol is coated uniformly with the finely ground active substance mixture. In this way, dust-free coated granules are obtained.
f) Suspension concentrat a) b) Mixture of active substance of the formula I with one of the actlve substances of the formulae II, III, II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII 20 % 20 %
Ethylene glycol 10 % 10 %
Nonylphenol polyethylene glycol ether (15 mol of EO) 6 % 6 %

.
~. :

2 ~ 8 ~

Sodium ligninsulfonate10 % 10 %
Carboxymethylcellulose 1 % 1 %
37 % aqueous formaldehyde solution 0.2 % 0.2 %
Silicone oil in the form of a 75%
aqueous emulsion 0.8 % 0.8 %
Water 32 % 12 %

The finely ground active substance mixture is mixed intimately with the additives. In this manner, a suspension concentrate is obtained from which suspensions of any desired concentration can be prepared by dilution with water.

It is often more convenient to formulate the active substance of the formula I and the component of the formulae II to XVII individually and only combine them shortly before appllcation in the applicator in the desired mixing ratio as a "tank mix" in water.

Biological examp es A synergistic effect is always present when the effect of the active substance combination I and II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII is greater than the total of the effects of the individually applied active substances.

The expected herbicidal action E 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):

E = X+ Y-(loo-x) In this formula, X = Percent growth inhibition after treatment with the compound of the fo;mula I with an application rate per hectare of p kg in comparison with the untreated control(=0%).

Y = Percent herbicidal action inhibition after treatment with a compound of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII with `` 20~8~6 an application rate per hectare of q kg in comparison with the untreated control.

E = Expected herbicidal effect (percent growth inhibition in comparison with theuntreated control) after treatment with the compound of the formula I and II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII at an application rate of p + q kg of active substance per hectare.

A synergism is present if the actually observed effect is greater than the expected value E.

The synergistic effect of the combinations of the active substance of the formula I with the active substances of the formulae II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI and XVII is demonstrated in the examples which follow.

Biolo~lcal examples:

Example B 1_ Pre-emergence test In a greenhouse, the seeds of the test plants are sown in plastic pots containing 0.51 of sterilised field soil. One day after sowing, the soil surface is sprayed with an aqueous dispersion of the active substance combination. The application rate of active ingredient is adjusted by suitably diluting the concentrate. In each case, 55 ml of dispersion are sprayed per m2. The test plants are grown on in the greenhouse and watered daily.

After 3 weeks, the herbicidal effect is assessed by comparison with an untreated control group. The percentage growth inhibition is recorded in comparison with the untreated control. The following linear key is used:

100 % = plants dead 50 % = moderate action 0 % = like untreated control The comparison results together with the expected values calculated by Colby's formula are compiled in Tables 1 and 2. The figures denote the symbols of the formulae of the active substances used in each case and their application rates and also the weeds which have been tested.

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20~5886 Table 1: Svner~istic action against Sor~hum halepense, pre-emer~ence:

Active substancesExpected valueActual growth and application(Colby's formula)inhibition rates in g of A.I.~ha 30 g I ---- 57 250 g II ---- 20 30 g I + 250 g II65 95 30 g I ---- 57 1000 g VII ---- 10 30 g I + 1000 g VII 61 95 30 g I ---- 57 250 g XII - ---- 20 30 g I + 250 g XII 65 95 30 g I ---- 57 125 g XVII ---- 0 30 g I + 125 g XVII 57 98 2~886 Table 2: SYnergistic action against Alopecurus myosuroides~ pre-emer ence:

Active substancesExpected valueActual growth and application~Colby's formula)inhibition rates in g of A.I./ha .. . . _ 30 g I ---- 3 500 g IV ---_ 30 30 g I + 500 g IV32 70 30 g I ---- 3 250 g VI ---- 20 30 g I + 250 g VI22 90 30 g I ---- 3 30 g XI ---- 60 30 g I + 30 g XI 61 95 30 g I ---- 3 250 g XVI ---- 30 30 g I + 250 g XVI 32 95 ..
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Example B2: Post-emergence test:

In a greenhouse, the seeds of the test plants are sown in plastic pots containing 0.51 of sterilised field soil. After emergence, the plants are sprayed in the 2- to 3-leaf stage with an aqueous dispersion of the active substance combination. The application rate of active ingredient is adjusted by suitably diluting the concentrate. In each case, 55 ml of dispersion are sprayed per m2. The test plants are grown on in the greenhouse and watered daily.

After 3 weeks, the herbicidal effect is assessed by comparison with an untreated control group. The percentage growth inhibition is recorded in comparison with the untreated control. The following linear key is used:

100 % = plants dead 50 % = moderate action O % = like untreated control The comparison results together with the expected values calculated by Colby's formula are compiled in Tables 3 to 5. The figures denote the symbols of the formulae of the active substances used in each case and their application rates and also the weeds which have been tested.

Table 3: Svner~istic effect a~ainst Sorghum halepense. wst-emer~ence:

Active substancesExpected valueActual growth and application(Colby's formula)inhibition rates in g of A.I./ha .

4 g I ---- 30 2000 g III ---- 0 4 g I + 2000 g III 30 90 4 g I ---- 30 125 g XIII ---- 40 4 g I + 125 g XIII 58 90 Table 4: Svnergistic effect a~ainst Alopecurus mvosuroides. post-emergence.

Active substancesExpected valueActual growth and application(Colby's formula)inhibition rates in g of A.I./ha 8 g I ---- 12 30 g IX ---- 30 8 g I + 30 g IX 38 95 8 g I ---- 12 1000 g XIV ---- 20 8 g I + 1000 g XIV 30 60 2 ~

15 g I ~ 50 60 g XV ---- 30 15 g I + 60 g XV 65 90 `, 2 ~ 8 8 ~

Table 5: Syner~istic effect a~ainst Di itaria san~uinalis. post-emer~ence:

Active substanceshxpected value Actual growth and application(Colby's formula) inhibition rates in g of A.I./ha . _ 8 g I ---- 43 1000 g V ---- o 8 g I + 1000 g V 43 90 8 g I ---- 43 2000 g VIII ---- 30 8 g I + 2000 g VIII 60 100 8 g I ---- 43 60 g X - ---- 70 8 g I + 60 g X 83 98 ''' ~ ' --, "'' :

Claims

1. A herbicidal composition containing a compound of the formula I

(I) and a synergistically active amount either of an active substance of the formula II

(II) or of an active substance of the formula III

(III) or of an active substance of the formula IV

(IV) or of an active substance of the formula V:

(V) or of an active substance of the formula VI:

(VI) or of an active substance of the formula VII:

[CH3(CH2)2]2NCOSCH2CH3 (VII) or of an active substance of the formula VIII:

(VIII) or of an active substance of the formula IX:

(IX) or of an active substance of the formula X:

(X) or of an active substance of the formula XI:

(XI) or of an active substance of the formula XII:

(XII) or of an active substance of the formula XIII:

(XIII) or of an active substance of the formula XIV:

(XIV) or of an active substance of the formula XV:

(XV) or of an active substance of the formula XVI

(XVI) or of an active substance of the formula XVII

(XVII).

2. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount either of an active substance of the formulae III or VI
or VIII or XII or XIII or XIV.

3. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula III.

4. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula VI.

5. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula VIII.

6. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula XII.

7. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula XIII.

8. A herbicidal composition as claimed in claim 1, containing a compound of the formula I
and a synergistically active amount of an active substance of the formula XIV.

9. A herbicidal composition as claimed in claim 1, in which the component of the formula I relative to the component of the formula II, III, IV, V, VI, VII, VIII, IX, X, XII, XIII, XIV, XV, XVI or XVII is present in a ratio by weight of 1: 1000 to 1: 1.

10. A method for controlling undesirable plant growth in crops of useful plants, in which a herbicidally effective amount of a composition as claimed in claim 1 is allowed to act on the crop plant or its environment.

11. A method as claimed in claim 10 for controlling weeds in crops of soya, sugar beet, oilseed rape, cotton and vegetables.

12. A method as claimed in claim 10 for controlling weeds in soya, sugar beet oilseed rape and cotton.

13. A method as claimed in claim 10 which comprises treating the crops of useful plants with application rates of the above mentioned composition which correspond to 0.01 to 2 kg of total amount of active substance per hectare.