AU624730B2

AU624730B2 - Synergistic mixture of a urea and a diphenyl ether derivative for the abscission of parts of plants

Info

Publication number: AU624730B2
Application number: AU60152/90A
Authority: AU
Inventors: Klaus Grossmann
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1989-08-07
Filing date: 1990-08-06
Publication date: 1992-06-18
Anticipated expiration: 2010-08-06
Also published as: EP0412364A1; IL95104A; ZA906170B; ES2045677T3; BR9003845A; DE59003311D1; CN1049265A; GEP19960329B; AU6015290A; EP0412364B1; IL95104A0; RU2002415C1; TR24620A; DE3926057A1; DK0412364T3

Description

COMMONWEALTH OF AUSTRALIA 624 73 PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority 4 Related Art Name of Applicant BASF AKTIENGESELLSCHAFT Address of Applicant: D-6700 Ludwigshafen, Federal Republic of Germany.

Actual Inventor Address for Service KLAUSS GROSSMANN WATERMARK PATENT TRADEMARK ATTORNEYS.

LOCKED BAG NO. 5, HAWTHORN, VICTORIA 3122, AUSTRALIA r i Complete Specification for the invention entitled: SYNGISTIC MIXTURE OF A UREA AND A DIPHENYL ETHER DERIVATIVE FOR THE ABSCISSION OF PARTS OF PLANTS The following statement is a full description of this invention, including the best method of performing it known to 1. O.Z. 0050/40997 l a- Synercistic mixture of a urea and a diphenyl ether derivative for the abscission of parts of plants The present invention relates to a synergistic mixture of a urea derivative I and a diphenyl ether derivative II for the abscission of parts of plants.

Ureas of the formula I 0

A-HN-C-NH-B

(I)

where A is a heteroaromatic radical A-i to A-3 N--N N R1 1 II

CI

A-i A-2 A-3 or a substituted phenyl radical A-4 S oR2 n A-4 where R' is hydrogen or methyl, R 2 is fluorine, chlorine or bromine, n is 1, 2 or 3 and B is cyclopentyl or cyclohexyl or is phenyl which is unsubstituted or monosubstituted to trisubstituted by fluorine, chlorine or bromine, are known abscission agents. An example is thidiazurone, which has the chemical name N-phenyl-N'- (1,2,3-thiadiazol-5-yl)-urea (cf. German Laid-Open S Applications DOS 2,506,690 and DOS 2,619,861).

i 20 In the case of crop protection and crop treatment agents of the formula I, it is fundamentally desirable to increase the specificity and the reliability of the A action.

It is an object of the present invention to provide an agent which reinforces the action of known agents.

Particularly at low temperatures, the active ingredients of the formula I exhibit fluctuations in activity; in particular, an increase in the rate of 2 O.Z. 0050/40997 action at low temperatures would improve the reliability of the action.

Particularly in cotton, but also in citrus crops, olives, pomes and stone fruits, abscission agents are of interest for facilitating harvesting.

The use of diphenyl ether derivatives II, for example sodium 5-[2-chloro-4-(trifluoromethyl)-phenoxy]- 2-nitrobenzoate, together with quinoline derivatives for regulating the length of growth of plants is disclosed in EP-A-208 245 (DE-A-35 24 319). The herbicidal activity of diphenyl ether derivatives II is disclosed in various publications, for example in US-A 4 036 929, DE-A-23 11 638, EP-A-0 040 898 or EP-A 3416. EP-A-0 001 427 states that a specially substituted diphenyl ether, ie. 2,6dichloro-3'-fluoro-4-trifluoromethyl-6'-nitrodiphenyl ether, has a desiccating and defoliating effect in cotton plants.

We have found that this object is achieved and that synergistic mixtures which have an effective content of a) one or more urea derivatives of the formula I 0

A-HN-C-NH-B

(I)

where A is a heteroaromatic radical A-i to A-3 N N

N

SI I iII Ri Cl A-i A-2 A-3 or a substituted phenyl radical A-4 R2 n A-4 where R 1 is hydrogen or methyl, R 2 is fluorine, chlorine or bromine, n is 1, 2 or 3 and B is cyclopentyl or cyclohexyl or is phenyl which is unsubstituted or 3 O.Z. 0050/40997 monosubstituted to trisubstituted by fluorine, chlorine or bromine, and b) one or more diphenyl ether derivatives of the formula II

CF

3 /-QNO2 (II) Cl

Z

where Z is a radical

-C-OR

3

-C-NHSO

2

R

4 or OR II

II

0 0 where R 3 is hydrogen, an alkali metal ion or alkaline earth metal ion, unsubstituted or substituted ammonium, alkyl of 1 to 4 carbon atoms or alkoxycarbonylalkyl ""II having a total of 1 to 6 carbon atoms and R 4 is alkyl of 1 to 4 carbon atoms, can be particularly advantageously used for the abscission of plant organs, in particular for the defoliation of cotton.

In the compounds II, R 3 is, in particular, hydrogen, sodium, ethoxycarbonylmethyl or ethoxycarbonyleth- 2-yl. Instead of the acid in the case or R 3 H, the corresponding alkali metal, ammonium or alkaline earth metal salts may also be used. Examples of alkali metal salts are lithium, sodium and potassium salts, and examples of alkaline earth metal salts are magnesium and i calcium salts. In the case of the ammonium salts, R 3 is, for example, the unsubstituted ammonium ion or ammonium ions in which 1 hydrogen atom or 2 or all 3 hydrogen atoms is or are replaced by substituents such as straight-chain or branched alkyl of 1 to 4 carbon atoms which may be substituted by halogen (Cl or Br), hydroxyl or C 1

-C

4 -alkoxy, or in which two of the alkyl radicals are bonded to one another to form a five-membered or sixmembered ring which may contain a further heteroatom, such as oxygen or nitrogen.

R

3 may furthermore be Ci-C 4 -alkyl, such as methyl, ethyl, propyl, isopropyl or butyl, or Ci-C 6 -alkoxy- _j -4 O.Z. 0050/40997 carbonylalkyl, for example Cl-C 3 -alkoxycarbonyl-Cl- or C 2 alkyl, such as Iethoxycarbonylmethyl, methoxycarbonylethyl, ethoxycarbonylethyl, propoxycarbonylmethyl and in particular ethoxycarbonylmethyl and ethoxycarbonyleth-2yl.

4 R iS Cl-C 4 -alkyl, eg. methyl, ethyl, propyl or butyl, in particular ethyl or methyl.

The following are examples of diphenyl ether derivatives: No. Structure Common name 0g~ 0 a 0 $0 V to 0 5 $00 I 0*0000 O 0 0050 V 0 0500 go 0 000 I 1. 1 11.2 11.3 11.4 C F 3 NO 2 C I COOH C F 3

NO

2 0 CI \COOCe'Na(D C F 3 NO 2 C I COOeNH 4

(D

CF

3 Q

NO

2 C I COOGK 9

CF

3 Q NO 2 Cl COOCH 2

COC

2

H

I I 0 CF 3 -0o NO 2 C1 COOCH-COC 2

H

I I I

CH

3 0

CF

3 Q NO 2 Cl C-NHS0 2

CH

3 I I 0 Ac ifluorfen Ac ifluorfen sodi um 11.5 Fl uor-oglycofen

IV

~o0I 11.6 11.7 Lactofen F oinesa f en 11 .8 CF 3 NO 2 C I OC 2

H

Ox ifl1uorf en I A ~1 5 O.Z. 0050/40997 The diphenyl ether derivatives II are commercial compounds or can be prepared as described in the prior art cited at the outset.

In the novel mixtures, the weight ratio of component I to component II is from 1 0.01 to 1 50, in particular from 1 0.2 to 1 20, particularly preferably from 1 0.2 to 1 Particularly advantageous mixtures contain the active ingredients N-phenyl-N'-(1,2,3-thiadiazol-5-yl)urea I.1 (known under the trade name Dropp®, common name: thidiazurone) and 5-[2-chloro-4- (trifluoromethyl)-phenoxy]-2-nitrobenzoic acid II.1 or its sodium saltA(known under the trade name Blazer)® or I.1 and ethoxycarbonylmethyl 5-[2-chloro-4-(trifluoromethyl)-phenoxy]-2-nitrobenzoate 11.5 (known under the trade name Superblazer®), LE.2 the components I.1 and II.l or I.1 and 11.5 in each case advantageously being present in a weight ratio of from 1 0.2 to 1 10 in each case.

The required application rates of pure active ingredient mixture, ie. without formulation assistants, is dependent on the composition of the plant stock, on the stage of development of the plants, on the climatic conditions at the place of use and on the method of application. In general, the application rates of urea derivative I are from 0.001 to 3, in particular from 0.1 to 1, kg/ha and those of diphenyl ether derivatives II are from 0.001 to 3, in particular from 0.01 to 3, kg/ha, and as a rule a total application rate of about 4 kg of active ingredient mixture per hectare is not exceeded.

The novel mixtures may be used, for example, in r the form of directly sprayable solutions, powders, suspensions, including concentrated aqueous, oily or other suspensions or dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents or granules, by spraying, atomizing, dusting, broadcasting or pouring. The application forms depend entirely on the intended uses; they should in any case ensure very fine l" 'y 7 Ae l 7 t T_ j 6 O.Z. 0050/40997 distribution of the active ingredients.

For the preparation of directly sprayable solutions, emulsions, pastes or oil dispersions, mineral oil fractions having a medium to high boiling point, such as kerosene or diesel oil, as well as coal tar oils and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, eg. benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, eg. methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclohexanol, cyclohexanone, chlorobenzene or isophorone, and strongly S, polar solvents, eg. dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone or water, are suitable.

Aqueous application forms can be prepared from "'15 emulsion concentrates, pastes or wettable powders (spray- .able powders ,oil dispersions) by adding water. For the S"preparation of emulsions, pastes or oil dispersions, the substances, as such or dissolved in oil or solvent, can be homogenized in water by means of wetting agents, adhesives, dispersants or emulsifiers. However, it is also possible to prepare concentrates which consist of *4 active substance and a wetting agent, dispersant or emulsifier and possibly a solvent or oil and which are suitable for dilution with water.

Suitable surfactants are alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, S, naphthalenesulfonic acid, phenolsulfonic acid, alkylarylsulfonates, alkylsulfates, alkylsulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenej 30 sulfonic acid, lauryl ether sulfate, fatty alcohol sul- Si fates, alkali metal and alkaline earth metal salts of fatty ac.d salts of sulfated hexadecanols, heptadecanols, octadecanols, salts of sulfated fatty alcohol glycol ethers, condensates of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensates of naphthalene or of naphthalenesulfonic acid with phenol and formaldehyde, polyoxyethylene octylphenol ether, 7 O.Z. 0050/40997 ethoxylated isooctylphenol, octylphenol, nonylphenol, alkylphenyl polyglycol ether, tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, ligninsulfite waste liquors and methylcellulose.

Powder, broadcasting, coated, impregnated and homogeneous granules can be prepared by binding the active ingredients into solid carriers. Solid carriers are mineral earths, such as silica gel, silicas, silicates, talc, kaolin, attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, kieselguhr, calcium sulfate, magnesium sulfate, magnesium oxide, milled plastics, fertilizers, eg. ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas and vegetable products, such as cereal meal, ground bark, woodmeal and nutshell meal, cellulose powder and other solid carriers.

The formulations contain from 0.1 to 95, preferably from 0.5 to 90, by weight of active ingredient.

For example, an agent contains about 10-80% by weight of active ingredient, about 30-90% by weight of liquid or Ssolid carriers and, if required, not more than 20% by weight of surfactants. If necessary, it may be diluted to a suitable application concentration.

The agents may be used as a complete formulation by mixing with conventional formulation assistants. Use in the form of a tank mix is also possible.

The action and the rate of action can be en- I hanced, for example, by means of activity-increasing additives, such as organic solvents, wetting agents and oils. This permits a reduction in the application rate of the actual active ingredient.

The agents are fed to the plants mainly by spraying the foliage. Application may be effected, for example, together with water as a carrier, by conventional n 8 O.Z. 0050/40997 spraying methods using spray liquor in amounts of about 100-1,000 1/ha. It is also possible to use the agents by the low volume and ultra-low volume methods or to apply them in the form of microgranules.

The novel mixture can be used alone or as a mixture with other agents or with other active ingredients.

If necessary, other defoliants, desiccants, crop protection agents or pesticides may be added, depending on the purpose.

We have also found that, if, for example, the active ingredients listed below are added to the novel mixtures, even better control of the undesirable resprouting of plants after desiccation or defoliation in cotton is achieved. Successful defoliation is maintained or is even improved: Herbicidal active ingredients from the group consisting of a. chloroacetanilides, such as 2-chloro-N-(2,6-dimethylphenyl)-N-(1H-pyrazol-l-ylmethyl)-acetamide (common name: metazachlor), described in German Laid-Open Application DOS 2,648,008, b. substituted quinoline-8-carboxylic acids, such as 3,7-dichloroquinoline-8-carboxylic acid, described in EP-A-104 389, and 3-methyl-7-chloroquinoline-8carboxylic acid, described in EP-A-60 429, c. cyclohexenone derivatives, such as 2[(1-ethoximino)butyl]-5-[2-(ethylthio)-propyl]--3-hydroxy-2-cyclohexen-1-one (common name: sethoxydim), described in German Laid-Open Application DOS 2,822,304, and 2- [l-ethoximino)butyl]-3-hydroxy-5-(2H-tetrahydrothiopyran-3-yl)-2-cyclohexen-l-one (common name: cycloxydim.), described in German Laid-Open Application DOS 3,121,355, d. phenoxyalkanecarboxylic acids, such as 4-chloro-2methylphenoxyacetic acid, e. 3-(isopropyl)-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide, described in German Laid-Open S-1 9 O.Z. 0050/40997 Application DOS 1,542,836 (Bentazon®)), f. dinitroanilines, such as N- -ethyipropyl dimethyl-2, 6-dinitroaniline, described in German Laid-Open Application DOs 2,241,408, g. imidazolinones, eg. 2-[4,S-dihydro-4-methyl-4-( 1methylethyl) -5-oxo-1H-imidazol-2-yl] -3-quinolinecarboxylic acid (Scepter®), h. 3?4,5,6-tetrahydrophthalimides, such as c-chloroacrylate) -4-chiorophenyl 6-tetrahydrophthalimide, described in EP-A 0240659, and i. sulfonylurea derivatives, such as the compounds known under the trade names Glean®, Ally®, Express®, Logran®, Setoff@, Muster®, Londax®, Onst®, Classic®, Bacon®, Harmony® or Remedy®), for example from DE-A 2 715 786, EP-A 7 687, 202 830, 44 808, 44 807, 136 061, 51 566, 7 687, 84 020, 30 142, 237 292 and 232 067, U.S. Patent 4,547,215 or Chemical Abstracts 102, 220 905.

Preferred components of the mixture are: 2-methyl-6-ethylethoxymethyl-2-chloroacetanilide 2-methyl-6-ethyl-N-(methoxy-1-methylethyl)-2-chloroactaild 2, 6-dimethyl-N- (lH-pyrazol-1-ylmethyl) -2-chloroacetanilide 2, 6-diethyl-N- (methoxymethyl) -2-chioroacetanilide 3-methyl-7-chloroquinoline-8-carboxylic acid (salts, esters) 3,7-dichloroquinoline-8-carboxylic acid (salts, esters) 2-[(1-ethoximino)-butyl]-5-[2-(ethylthio)-propyl]-3hydroxy-2-cyclohexan-1-one (salts) 2 (l-trans-chloroallyloximino) -butyl] (ethylthio) propyl]-3-hydroxy-2-cyclohexan-1-one (salts) (1-trans-chloroallyloximino)-propyl]-5-[2-(ethylthio) propyl ]-3-hydroxy-2-cyclohexan-1-one (salts) (1-ethoximino) -butyl [2-H-tetrahydrothiopyran-3yl) -3-hydroxy-2-cyclohexan-1-one (salts) 2-l -ethoximino)-propyl]--5-(2,4, 6-trimethylphenyl)-3- 10 0 0050/40997 hydroxy-2-cyclohexan-1-one (salts) 2-methyl-4-chlorophenoxyacetic acid (salts, esters, amides) 2-[2-methyl-4-chlorophenoxy]-propionic acid (salts, esters, amides) 4-[2-methyl-4-chlorophenoxy]-butyric acid (salts, esters, amides) 4-[2,4-dichlorophenoxy]-butyric acid (salts, esters, ainides) 2-[2,4-dichlorophenoxy]--propionic acid (salts, esters, amides) 2,4-dichlorophenoxyacetic acid (salts, esters, amides) 3,5,6-trichloropyrid-2-yloxyacetic acid (salts, esters, amides).

3-(1-methylethyl)-lH-2,1,3-benzothiadiazin-4-(3H)-one Ito* 2,2-dioxide (salts) 3- -methylethyl) -1-cyano-2 3-benzothiadiazin-4- (3H)one 2,2-dioxide (salts) N- -ethylpropyl) 4-dixnethyl-2 ,6-dinitroan.iline 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-lH- 401qimidazol-2-yl ]-3-quinolinecarboxylic acid a-chloracrylate)-4-chlorophenyl]-3,4,5, 6tetrahydrophthalimide Defoliants and desiccants as stated, for example, in Cathey, G.W. (1986) Physiology of defoliation in cotton production, in Cotton Physiology (J.R.

Mauney, J. McD. Stewart, eds.) The Cotton Foundation reference book series, No. 1, Chapter 14, 143-153, and in Morgan, P.W. (1985) Chemical manipulation of abscission and desiccation, in Agricultural Chemicals of the Future Hilton, ed.) BARC Symposium 8, 61-74, Rowman Allanheld, Ottawa.

a 6,7-Dihydrodipyridol(1,2-a:2',1'-c)pyridilium ion as dibromide monohydrate salt (common name: diquat) and 1,1'-dimethyl-4,4'-bipyridiniuu ion as dichloride or dimethylsulf ate salt (common name: paraquat).

11 O.Z. 0050/40997 b. 2-Chioroethyiphosphonic acid (Ethrel®) C. S, S, S-Tributyl phosphortrithioate and S, S, S-tributyl phosphortrithio ite d. 2,3-Dihydro-5,6-dimethyl-1,4-dithiin-1, 1,4,4-tetraoxide (Harvade®) e. Salts of N-(phosphonomethyl)-glycine, such as the isopropylammonium salt (Roundup®) f. Magnesium chlorate and sodium chlorate g. 1, 2-Dihydropyridazine-3 ,6-dione h. 7-Oxabicyclo[2.2.l]heptane-2,3-dicarboxylic acid (common name: endothall).

Preferred components of the mixture are: 2 -Chloroethylphosphonic acid S,S,S-Tributyl phosphortrithioate and -trithioite 2,3-Dihydro-5, 6-dimethyl-1,4-dithiine-1, 1,4 ,4-tetraoxide N- (Phosphonomethyl) -glycines (salts) 1, 2-Dihydropyridazine-3 ,6-dione Perchlorates 7-Oxabicyclo[2 1]heptane-2, 3-dicarboxylic acid (sa.lts, esters, amides) 1, 1-Ethylene-2, 2-bipyridyliun dibromide Growth retardants from the group consisting of a. quaternary ammonium salts from the group consisting 2. of the N,N-dimethylazacycloheptanium salts, N,Ndixethylpiperidinium salts, N,N-dimethylhexahydropyridazinium salts, N,N-dimethyltetrahydro- 7. pyridazinium salts, N-methylpyridinium salts, N,Ndimethylpyrrolidinium salts and N, N, N-trimethyl -N- 2-chloroethylammonium salts, in particular N-2chloroethyl-N-trimethylammonium chloride (common name: chlormequat chloride) and N,N-dimethylpiperidinium. chloride (common name: mepiquat chloride), b. pyrimidine compounds as disclosed in U.S. Patent 3,818,009 and in Journal of Plant Growth Regulation 7:27, 1988 (for example those having the common name ancymidol or flurprimidol) C. pyridine compounds disclosed in DE-A-30 15 025,

L

I

12 O.Z. 0050/40997

I

1 4 d. norbornadiazetines, as described in German Laid-open Applications DOS 2,615,878 and DOS 2,742,034, e. triazole compounds having a growth regulating action, as descrtibe in European Application 881043- 20.2, in British Crop Protection Conference Weeds 1982, Vol. 1, BCPC Publications, Croydon, 1982, page 3, in Plant Cell Physiol. 25, 611, in Pestic. Sci.

19, 153, in J. Agron. Crop Sci. 158, 324 or in J.

Plant Growth Regul. 4, 181, for example 1-phenoxy- 3-(1H-1,2,4-triazol-1-yl)-4--hydroxy-5,5-dimethylhexane, f. 2 -acyl-3-hydroxycyclohex-2 -en-1 -ones, as described in EP-A-126 713 or 123 001, and g. 1-(4-chlorophenoxy)-3,3-dimethyl--[1,2,4-triazol- 1-yl]-butan-2-one (common name: triadimefon) N-[2 ,4-dimethyl-5-[trifluoromethylsulfonylamino] phenylacetamide (common name: mefluidide) 2-chloro-2 6 -diethyl-N-[methoxymethyl] -acetanilide (common name: alachior) S-ethyl dipropylthiocarbamate (common name: EPTC) succinic 2,2-dimethyihydrazide (common name: daminozide).

Preferred components of the mixture are: N,N,N-Trimethyl-N-2-chloroethylammonium salts N,N-Dimethylpiperidinium salts N-Methylpyridinium salts a-Cyclopropy-a- 4-methoxyphenyl) c-Cyclopropyl-a- (4-trifluoromethoxyphenyl) *yrimidinemethanol 5-(4-Chlorophenyl)-3,4,5,9,10-pentaazatetracyclo- [5.4 0 2 ,6.08- 11 -dodeca-3,9-diones all-cis-8- (4-Chlorophenyl) 8-triazatetracyclo- [4.3.1.0 .02,5.0 7 9 ]-dec-3-one Succinic mono-N, N-dimethylhydrazide Ethyl N, N-dipropylthiolcarbamate N-2 ,4-Dimethyl-5- (trifluoromethyl) -sulfonylamninophenylacetamide 4, 4 44 4 4 4 ''44 13 O.Z. 0050/40997 1-(4-Chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)- 2-butanone 2-Propylcarbonyl-5-ethoxycarbonyl-3-hydroxy-2-cyclohexen- 1-one 1-(1,2,4-Triazol-1-yl)-1-methoxy-2-(2,4-dichlorophenyl)propan-2-ol 2,2-Dimethyl-4-(1,2,4-triazol-1-yl)-6-phenoxyhexan-3-ol 2,2-Dimethyl-4-(1,2,4-triazol-1-yl)-5- (4-chlorophenyl) pentan-3-ol 2,2-Dimethyl-4-(1,2,4-triazol-1-yl)-5-(4-chlorophenyl)pent-4-en-l-ol 2,2-Dimethyl-4-(1,2,4-triazol-1-yl)-5-cyclohexylpent-4en-3-ol 1-(5-Methyl-1,3-dioxan-5-yl)-4-(1,2,4-triazol-1-yl)-4-(4trifluoromethylphenyl)-propen-2-ol.

Use Examples The comparative agents used were the individual active ingredients N-phenyl-N'-(1,2,3-thiadiazol-5-yl)urea and sodium 5-[2-chloro-4-trifluoromethyl)phenoxy]-2-nitrobenzoate (11.2) and ethoxycarbonylmethyl 5-[2-chloro-4-trifluoromethyl)-phenoxy]-2-nitrobenzoate (11.5).

The active ingredients were used in the form of their ready-formulated commercial products. The data on the quantity-related action are based on the active ingredient content.

The amount of water in the formulations was 1000 1/ha.

The test plants used were young, 5-leaved or 6leaved cotton plants (without cotyledons) of the Stoneville 825 variety.

USE EXAMPLE 1 The cotton plants were grown under greenhouse conditions (day/night temperature 20/13"C, relative humidity from 50 to 70%) and the foliage was treated to run-off with aqueous formulations of the stated active ingredients (with the addition of 0.15% by weight, based 14 O.Z. 0050/40997 on the spray liquor, of the fatty alcohol alkoxylate Plurafac® LF 700). 7 days after application of the active ingredient, the number of dropped leaves and the degree of defoliation in were determined. In the case of the untreated control plants, no defoliation occurred.

Agent, containing Converted Defoliation active ingredient No. application rate rkq/hal] %1 I.1 (Dropp®) 0.125 0 0.500 6 II.2 (Blazer®) 0.062 0.125 78 0.250 88 I.1 11.2 0.125 0.062 62 I.1 11.2 0.125 0.250 93 W14 0 qn 04 0 (4,4L 0ti Sa Particularly under unfavorable, cool conditions, a synergistic effect is observed as a result of the cooperation of the active ingredients I.1 and 11.2.

USE EXAMPLE 2 4o* Young cotton plants were grown under greenhouse conditions (day/night temperature 21/15 0 C, relative humidity from 50 to 70%) and the foliage was treated to run-off with aqueous formulations of the stated active ingredients (with the addition of 0.15% by weight, based on the spray liquor, of the fatty alcohol alkoxylate Plurafac® LF 700). 7 days after application of the active ingredient, the number of dropped leaves and the degree of defoliation in were determined. In the case of the untreated control plants, no defoliation occurred.

II/

15 O.Z. 0050/40997 Agent, containing active ingredient No.

Converted application rate Defoliation [rk/hal [%1 I.1 (Dropp®) 0.016 0 0.030 6 (Superblazer®) 0.030 62 0.062 83 I.1 11.5 0.016 0.062 94 Particularly under unfavorable, cool conditions, a synergistic effect is observed as a result of the cooperation of the active ingredients I.1 and lo~ r tcr d ii i j

Claims

1. A synergistic mixture for the abscission of parts of plants, which comprises an effective content of a) one or more urea derivatives of the formula I 0 II (I A-HN-C-NH-B where A is a heteroaromatic radical A-i to A-3 N -N N IIN II RC1 Cl A-i A-2 A-3 S' or a substituted phenyl radical A-4 R2 n A-4 where R 1 is hydrogen or methyl, R 2 is fluorine, chlorine or bromine, n is 1, 2 or 3 and B is cyclopentyl or cyclo- hexyl or is phenyl which is unsubstituted or mono- substituted to trisubstituted by fluorine, chlorine or bromine, and b) one or more diphenyl ether derivatives of the formula II CF3- O -N0 2 (II) Cl Z where Z is a radical -C-OR 3 -C-NHSO 2 R4 or OR 4 0 0 where R 3 is hydrogen, an alkali metal ion or alkaline earth metal ion, unsubstituted or substituted ammonium, alkyl of 1 to 4 carbon atoms or alkoxycarbonylalkyl having a total of 1 to 6 carbon atoms and R 4 is alkyl of 1 to 4 carbon atoms.

2. A synergistic mixture as claimed in claim 1, 17 O.Z. 0050/40997 wherein the components I and II are present in a weight ratio of from 1 0.01 to 1

3. A synergistic mixture as claimed in claims 1 and 2, wherein the components I and II are present in a weight ratio of from 1 0.2 to 1

4. A synergistic mixture for the abscission of parts of plants, which comprises an effective content of N- phenyl-N'-(l,2,3-thiadiazol-5-yl)-urea I.1 and 5-[2- chloro-4-(trifluoromethyl)-phenoxy]-2-nitrobenzoic acid II.1 or its sodium salt 11.2, the components I.1 and II.1 or 11.2 being present in a weight ratio of from 1 0.2 to 1 A synergistic mixture for the abscission of parts 00 o o of plants, which comprises an effective content of N- phenyl-N'-(1,2,3-thiadiazol-5-yl)-urea I.1 and ethoxy- im carbonylmethyl 5-[2-chloro-4-(trifluoromethyl)-phenoxy]- 2-nitrobenzoate 11.5, components I.1 and 11.5 being present in a weight ratio of from 1 0.2 to 1

6. A method for the abscission of parts of plants, wherein an agent as claimed in claim 1 or 2 or 3 or 4 or 5 is allowed to act on plants.

7. Use of an agent as claimed in claim 1 or 2 or 3 or 4 or 5 for the defoliation of cotton plants. DATED THIS 3rd day of August, 1990 BASF AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTORNEYS, 2nd Floor, The Atrium, 290 Burwood Road, HAWTHORN. VICTORIA 3122.