CH637003A5 - Method of controlling weeds - Google Patents

Description

The present invention now relates to a method for controlling weeds by treatment with a weed control agent, which is characterized in that the weed control agent is applied to the weeds in the form of a foam, the foam being applied to some leaves of the weed plant. The present invention preferably relates to a method for combating winds.

According to the invention, an aqueous stiff foam containing weed control agent is applied to the leaves of the weeds to be destroyed by means of a foam-producing apparatus such as a spraying device or a so-called aerosol can. The foam which can be used in the present process adheres to the leaves during the entire drying time, so that after the treatment of the leaves the herbicidal composition has no great tendency to flow onto the neighboring plants or onto the soil.

The foam is preferably applied to only two to three individual leaves of each winch plant with the aid of a foaming device, the nozzle of which is held very close to the leaf.

Such a foam can be generated from any solutions or dispersions of the active ingredients containing foam-forming agents. However, the foam 15 is preferably obtained from an aqueous colloidal solution of the herbicidal active ingredient (s) and a foam-forming surface-active agent. The weight contents of active ingredient component (s) and of surface-active agent in the solution thus obtained are preferably of the same 20 order of magnitude, in particular between 1: 1 and 1: 2. This enables the design of a molecular framework within the foam, which gives the foam such a consistency that the foam adheres to the leaves during the entire drying time.

25 The foam-generating agent is preferably in the form of a colloidal, aqueous, clear solution or dispersion which, when mixed with air or with a propellant, forms a rigid, non-flowing, stable foam. It preferably contains 0.1 to 5% by weight of one or 30 more herbicidal active ingredients (s), 0.2 to 10% by weight of one or more surface-active ingredients (emulsifiers and foaming agents), 95 to 99.7 % By weight of liquid carrier, which is preferably water, and may also contain further constituents, for example foam stabilizers, preservatives, corrosion inhibitors, solvents, dye (s) and / or liquid propellant.

Examples of herbicidal active ingredients which can be used are: 3-amino-1,2,4-triazole, the herbicidally active derivatives of uracil such as 5-sec-bromo-3-butyl-6-methyluracil and 3-cyclohexyl-5,6- trimethyleneuracil, the herbicidally active derivatives of urea such as N, N-dimethyl-N'-phenylurea, bis- (2,2,2-trichloro-l-hydroxyethyl) urea, 3-phenyl-1,1-dimethylurea, 3- (p-chlorophenyl) - 1,1-di-45 methylurea, 3- (3,4-dichlorophenyl) -l, l-dimethylurea, n-butyl-3- (3,4-dichlorophenyl) -l methyl urea and 3-m-nitrophenyl-l, l-dimethyl urea; 2,6-dichlorobenzonitrile, the thiocarboalkoxydisulfides such as thiocarboethoxydisulfide, thiocarboisopropoxydisulfide and thiocarbometh-50 oxydisulfide; the dithiocarbamates such as 2-chloroalyl-N, N-di-ethyldithiocarbamate, N-methyldithiocarbamate and ethyl-N, N-di-n-propylthiocarbamate, the quaternary salts of bipyridilium such as the dibromide of 1,1'-ethylene-2,2 '-bipyridylene (dibromide from Diquat) and the dichloride from 1,1'-55 dimethyl-4,4'-bipyridylene (dichloride from Paraquat), the 7-oxabicyclo- (2.2, l) -2.3 -heptanedicarboxylic acid and its disodium salt, the halogenated benzoic acids and their salts or esters derived from these acids, such as trichlorobenzoic, tetrachlorobenzoic, pentachlorobenzoic acids or 6o the 2-ethylhexyl-2,3,4,5-tetrachlorobenzoate which halogenated Phenoxyalkanoic acids such as 2,4-dichlorophenoxypropionic acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 2,4,5-trichlorophenoxypropionic acid, 2-methyl-4-chlorophenoxypropionic acid, 2,4-dichlorophenoxybut- 65 teric acid and 2-methyl-4-chlorophenoxyacetic acid and their salts or the esters derived from these acids and the symmetrical triazines such as the 4,6-diamino-symme trian triazines.

Preferred herbicidal active ingredients are the salts and esters of the acids of the formula I:

#T

(X) <_) - I- ° -C „H2n1n-C00H •

R

wherein X is 1 to 4 substituents selected from chlorine and bromine, R is a hydrogen atom or a methyl or methoxy group, n is an integer from 1 to 3 and m is 0 or the number 1.

The esters formed with these acids preferably derive from a primary or secondary alkanol having 1 to 12 carbon atoms or an alkoxyalkanol having a total of 3 to 9 carbon atoms.

However, particularly preferred herbicidal compositions are those which contain active compounds of the formula (I) in the form of their alkali metal, amine or ammonium salts. The water-soluble amine salts, in particular the dimethylamine salts, of the following acids are particularly preferred in this group:

2,3,6-trichlorobenzoic acid,

3,6-dichloro-2-methoxybenzoic acid (dicamba),

2,4-dichlorophenoxyacetic acid (2,4-D acid),

4-chloro-2-methylphenoxyacetic acid,

2,4,5-trichlorophenoxyacetic acid,

2- (2,4-dichlorophenoxy) propionic acid,

2- (4-chloro-2-methylphenoxy) propionic acid (MCPP acid)

2- (2,4,5-trichlorophenoxy) propionic acid,

4- (2,4-dichlorophenoxy) butyric acid,

4- (4-chloro-2-methylphenoxy) butyric acid and

4- (2,4,5-trichlorophenoxy) butyric acid,

2-methyl-4-chlorophenoxybenzoic acid (MCPA acid).

A mixture of 2,4-D-acid dimethylamine salt and MCPA acid dimethylamine salt in a weight ratio of 1: 2 is very particularly preferred. A mixture of 2,4-D-acid dimethylamine salt, MCPP acid dimethylamine salt and dicamba dimethylamine salt in a weight ratio of 10: 10: 1 is also preferred.

The usual foam-producing anionic, preferably nonionic, agents, such as e.g. Saponins, soaps, fatty alcohol sulfates, alkylarylsulfates, alkylarylsulfonates, sarcosinates, salts of the condensation products from saturated fatty acids with hydroxyethanesulfonic acid, salts of fatty acids-polypeptide condensation products, salts of lauryl- (poly-1-oxapropenes) -oxaethane-carboxylated fatty acids, monoglypolyalkenesulfonyl sulfonates of fatty alcohols glycol ether or alkylphenol polyethylene glycol ether.

At the same time, the surface-active agent must have very good foaming power and, if appropriate, the ability to dissolve the herbicidal active ingredient (s). The mixtures of at least two nonionic emulsifiers and an anionic foaming agent preferably have this property.

An important feature of the invention is that the foam-generating agent contains the herbicidal component and the surface-active agent in weight ratios between 1: 1 and 1: 2.

As blowing agents which can be used to produce a foam, mention should be made of butane, isobutane, propane, dimethyl ether, trichlorofluoromethane, dichloride fluoromethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, tetrafluoromethane and octafluorocyclobutane.

The liquid carrier preferably consists of water. But it can also contain organic solvents

637 003

e.g. lower alcohols such as methyl alcohol, ethyl alcohol or ethoxyethanol and methoxyethanol, isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and cyclohexa-non, aromatic hydrocarbons such as tetrahydronaphthalene, aliphatic hydrocarbons such as kerosene, chlorinated hydrocarbons such as dichloromethane, trichloromethane, trichloromethane, trichloromethane, oxygen-containing heterocyclic compounds such as dioxane, aliphatic carboxamides such as dimethylformamide and dimethylacetamide and esters which are formed from alkanoic acids and alkanols, these having a total of between 3 and 15 carbon atoms, such as methyl acetate, butyl acetate, amyl acetate, ethyl propionate, ethyl butyrate, Amylbutirate, ethyl heptanoate, butyl heptanoate, heptyl haptanoate, ethyl caprylate, methyl caprate, ethyl caprate, methyl laurate, ethyl laurate, isopropyl laurate and methyl myristate, dimethyl sulfoxide, mineral oils, vegetable oils, animal oils and liquids generally polymerize resins for plasticizing are used, such as in particular chlorhexadecane, chloroctadecane, dioctyl adipate, dibutyl sebacate, dioctyl sebacate, dioctyl azelate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, diphenyl phthalate, dicresyl phthalate, di-cyclohexyl phthalate, dioctyl phosphate, dibutyl phthalate, dibutyl phthalate, dibutyl phthalate, dicctyl phosphate, This is because these organic agents can be used to bring the herbicidal active ingredient into aqueous solution.

The compositions can be prepared by simply mixing the components or, in a first step, by dissolving or dispersing the herbicidal active ingredient (s) in the liquid surfactant or in an organic solution thereof, optionally with gentle heating, and in one second step, the solution thus obtained is diluted with water.

The weed-killing effect is already visible 2 to 3 hours after the treatment and becomes complete after 1 to 3 weeks after which the entire winch plant has been killed.

The method according to the invention is illustrated in the following example.

example

1.66 parts by weight of 4-chloro-2-methylphenoxyacetic acid dimethylamine salt (corresponding to 1.46 parts by weight of 4-chloro-2-methylphenoxyacetic acid) and 0.83 part by weight of 2,4-dichlorophenoxyacetic acid dimethylamine salt in 2.05 parts by weight of a surfactant, consisting of 0.02 parts by weight of a mixture of a Ca salt of an alkylarylsulfonate and a nonylphenol polyethoxyethanol, (which at 20 ° C as a 0.1% water solution has a surface tension of 35 dynes / cm, and as a 0.01% water solution has a surface tension of 40 dynes / cm), 0.03 parts by weight of isooctylphenol poly-ethoxyethanol with 9 to 10 oxyethylene units and 2 parts by weight of a nonylphenol polyethoxyethanol (AN-TAROX / CO 730 from General Aniline and Film Corporation). The solution obtained is mixed with 0.1 part by weight of a water-soluble preservative, e.g. a mixture of an arylmethanol and a haloalkylacylaminomethanol, and 95.46 parts by weight of water were added. A clear solution is obtained, which is applied to the winch blades as a foam from a plastic bottle equipped with a special valve. The foam adheres well to the winch blades and does not flow to the floor. An effect is already visible 2 to 3 hours after the treatment and the treated winds are completely destroyed after 2 to 3 weeks.

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Claims (7)

637 003 1. A method for controlling weeds by treatment with a weed control agent, characterized in that the weed control agent is applied to the weeds in the form of a foam, the foam being applied to some leaves of the weed plant. 2. The method according to claim 1, characterized in that the weeds are applied with a foam containing 0.1 to 5 percent by weight of one or more herbicidal active ingredients, 0.2 to 10 percent by weight of one or more surfactants, and 85 to 99.7 percent by weight Contains water or water-containing liquid carrier. 2nd PATENT CLAIMS 3. The method according to any one of claims 1 and 2, characterized in that the weeds are applied with a foam which is a salt or an ester of an acid of the formula: V A (I) V V - [- 0-C H „] -C00H X / n m R wherein X contains 1 to 4 substituents selected from chlorine and bromine, R is a hydrogen atom or a methyl or methoxy group, n is an integer from 1 to 3 and m is 0 or the number 1. 4. The method according to any one of claims 1 to 3, characterized in that weeds are applied with a foam which comprises a mixture of 2,4-dichlorophenoxyacetic acid or its water-soluble salts and of 4-chloro-2-methylphenoxyacetic acid or its water-soluble salts contains in a weight ratio of 1: 2. 5. The method according to any one of claims 1 to 4, characterized in that the weed is applied with a foam which is a mixture of 2,4-dichlorophenoxyacetic acid or its water-soluble salts, from 2- (4-chloro-2-methylphenoxy) -propionic acid or its water-soluble salts and from 3,6-dichloro-2-methoxybenzoic acid or its water-soluble salts in a weight ratio of 10: 10: 1. 6. The method according to any one of claims 1 to 5, characterized in that the weed is applied with a foam which contains a surface-active agent which is present in weight ratios to the herbicidal component between 1: 1 and 2: 1 and which at the same time has good foaming power and has good dissolving power for the herbicidal component. 7. The method according to claim 1 for the destruction of winches. The control or extermination of unwanted grass and weeds which grow near vegetable plants or garden ornamental plants is a difficult problem for the gardener, because when they are treated with a herbicidal solution, emulsion or suspension or with a herbicidal wettable powder, the neighboring crop plants easily can be damaged.