CH620097A5 - Herbicide. - Google Patents

Description

The invention relates to a weed killer (herbicide) which is particularly effective against wind oat.

Wind oat (Avena fatua) is a weed that is widespread all over the world and increasingly affects the growth of cereals and grains. The economic losses caused by the wind oat are already significant sums annually.

A group of compounds which are known for their high degree of herbicidal activity against wind oat while at the same time being extremely selective for cereals are the N, N-disubstituted alanine derivatives, of which both herbicides for wheat fields and those for barley fields are commercially available.

It has now been found that a mixture of one of these N, N-disubstituted alanine derivatives with 3-isopropyl-1H-2, 1, 3-benzothiadiazine (4), 3H-one-2,2-dioxide is an excellent herbicide against wind oat represents, in which the effect is enhanced by synergistic influence of the components.

The invention accordingly relates to a weed killer which is characterized in that the active ingredient present therein consists of:

(a) 3-isopropyl-1H-2, 1,3-benzthiadiazine (4), 3H-one-2,2-dioxide (hereinafter referred to as the "dioxide"); and

(b) an N, N-disubstituted alanine derivative of the following general formula:

45

50

where Y and Z are each chlorine or fluorine and X is oxygen or sulfur and R represents one of the following groups:

a group of the formula -ORi, in which Ri represents a hydrogen atom, a metal salt-forming or an optionally alkyl-substituted ammonium ion or an optionally substituted alkyl, cycloalky, aryl, alkenyl or alkaryl group;

a group of the formula -SR2, in which R2 represents an optionally substituted alkyl, cycloalkyl, aryl, alkenyl or alkaryl group; or a group of the formula -NR3R4 or -ON = CR3R4, in which R3 and R4 each have a hydrogen atom, a hydroxyl radical or an optionally substituted alkyl, alkenyl, aryl, alkaryl, heterocyclyl, alkoxy, alkylthio or

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Represent amino group or in which R3 and R * together form a polymethylene group, which may optionally be interrupted by one or more heteroatoms, with the condition that X can not be oxygen, Y and Z chlorine and R ethoxy at the same time.

Mixtures of ethyl N-benzoyl-N- (3,4-dichlorophenyl) -2-aminopropionate and 3-isopropyl-1H-2, l, 3-benzothiadiazine (4), 3H-one-2,2- Dioxide are known from DE-OS 2 336 444.

The substituents optionally present in the alanine derivative are preferably one or two chlorine, fluorine, alkyl (1-4C) or alkoxy (1-4C) groups. The alkyl, alkenyl, alkoxy and alkylthio groups contained in the above general formula suitably contain up to 6 and preferably up to 4 carbon atoms. The aryl, alkaryl, cycloalkyl, heterocyclyl and polymethylene groups advantageously contain up to 10 and preferably up to 7 carbon atoms. The heteroatoms optionally present in the polymethylene or in the heterocyclyl group can be oxygen, nitrogen or sulfur atoms, but are preferably one or two oxygen and / or nitrogen atoms.

By far the best results have been obtained by mixing the dioxide with the 3-chloro-4-fluoro-alanine derivative, i. H. with that compound of formula I in which Z represents a fluorine atom and Y represents a chlorine atom.

Examples of these N, N-di-substituted alanine derivatives and of processes for their preparation can be found in the following published patent applications:

DE-OS 1 643 527 DE-OS 2 109 910 DE-OS 2 302 029

DE-OS 2 349 970 DE-OS 2 504 319 DE-OS 2 460 691.

Alanine derivatives with the following general formula are particularly preferred:

CO

-N .:

CH-COQR (II) CH,

wherein Y is chlorine and Z is fluorine and R is a hydrogen atom or an alkyl group with up to 6 carbon atoms, e.g. B. represents methyl, ethyl or isopropyl. Among these compounds, one of the best herbicides for controlling wind oat in barley fields is the compound of Formula II, in which:

Z = fluorine,

Y = chlorine and R = isopropyl.

One of the best herbicides for use in wheat fields is another compound according to Formula II, in which:

Z = fluorine,

Y = chlorine and R = methyl.

The alanine derivatives can be in optically active form, with - generally speaking - the left-handed isomer being the most active form, which therefore also forms a preferred constituent of the active compounds according to the invention.

The examination of a number of different dosages shows that the mixtures according to the invention have a synergistic herbicidal action against wind oats. This is particularly surprising because, for one of the components, the dioxide, no effectiveness against wind oat has been found to date. In addition, despite the increased activity against wind oat, no significant increase in the effect of the compositions on cereals can be observed, so that they can be used without risk as selective herbicides in crops infested with wind oat.

The invention enables control of wind oats in many stages of development by applying the agents to the plants after emergence. In grain stocks, the wind oat can be combated by applying the agents according to the invention in an amount of 0.25-2.0 kg / ha, the weight ratio of alanine derivative to dioxide being 1: 0.2-1: 25, preferably 1: 0.5-1: 15.

The herbicides according to the invention may also contain a carrier, a surface-active agent or both, in order to facilitate the application in the desired dosage to the stocks infested by wind oat. The term “carrier” means a solid or liquid material that can be inorganic or organic and of synthetic or natural origin.

Typical solid supports are e.g. B. natural or synthetic clays and silicates, such as natural silica, such as diatomaceous earth and aluminum silicates, e.g. B. kaolinite, montmo-rillonite and mica. Typical liquid carriers are ketones, e.g. B. methylcyclohexanone, aromatic hydrocarbons, e.g. B. methylnaphthalenes, petroleum fractions, such as petro-leumxylenes and light mineral oils, and chlorinated hydrocarbons, e.g. B. carbon tetrachloride. Mixtures of liquids are often suitable.

In addition, the herbicides can contain surface-active agents and / or adhesives. The former can be emulsifying or dispersing or wetting agents, which can be non-ionic or ionic. It can be any surfactant used in herbicides or insecticides. Examples include a. the sodium or calcium salts of polyacrylic acids and lignosulfonic acids; the condensation products of fatty acids or aliphatic amines or amides with at least 12 carbon atoms with ethylene oxide and / or propylene oxide; Fatty acid esters of glycerol, sorbitol, sucrose or pentaerythritol, and their condensates with ethylene oxide and / or propylene oxide; Condensation products of fatty alcohols or alkylphenols, e.g. B. p-octylphenol or p-octylcresol, with ethylene oxide and / or propylene oxide and sulfates or sulfonates of these condensation products; Alkali or alkaline earth metal salts, preferably the sodium salts, of esters of sulfuric or sulfonic acid with at least 10 carbon atoms in the molecule, e.g. B. sodium lauryl sulfate, sodium sec-alkyl sulfates, sodium salts of sulfonated castor oil and sodium alkyl aryl sulfonates such as sodium dodecylbenzenesulfonates; and polymers of ethylene oxide or copolymers of ethylene and propylene oxide.

Aqueous dispersions and emulsions, e.g. B. Preparations that are obtained when diluting a wettable powder or concentrate according to the invention with water also fall under the invention. The emulsions can be of the water-in-oil or oil-in-water type and have a thick, mayonnaise-like consistency.

The agents according to the invention can be applied to the wind oat plants in a conventional manner. The dusts and liquid preparations can be prepared in the usual way by mechanical or manual spraying5

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directions are distributed over the plantation or the terrain, for which planes can also be used if necessary, since the agents are effective even in low doses.

If necessary, the active compounds according to the invention can also be mixed with other herbicides against wind oat, for. B. with 4-chloro-2-butynyl-m-chlorocarbanilate (common name: Barban;) or methyl 2-chloro-3- (4-chlorophenyl) propionate (common name: chlorophenpropmethyl;) or 1,2-dime -thyl-3,5-diphenylpyrazolium methyl sulfate.

In order to achieve a broader spectrum of activity, in particular with respect to weeds of the broad-leaf type, the active compounds according to the invention can be mixed with compatible herbicides which are active against broad-leaf plants but are gentle on cereal plants. Examples of such selective broad-leaf herbicides are the derivatives of phenoxyalkanonic acid of the general formula:

Z '

wherein X 'represents a chlorine atom or a methyl group, Y' represents a chlorine atom and Z 'represents a hydrogen or chlorine atom, while A represents an alkylene group of 1-4 carbon atoms and R' represents a carbonyl group, including their salts and esters. Particular examples are: 2,4-dichlorophenoxyacetic acid; (±) -2- (2,4-dichlorophenoxy) propionic acid; 4-chloro-2-methylphenoxyacetic acid; (±) -2- (4-chloro-2-methylphenoxy) propionic acid and 4- (4-chloro-2-methylphenoxy) butyric acid.

The invention will be explained in more detail by means of the examples, in which the effectiveness of the agents according to the invention against wind oat (Avena fatua) is shown in stocks of jelly; culture oats (Avena sativa) were used as cereals in the examples. Experience has shown that the data obtained from such experiments with culture oats are representative of the effect on wind oats and that in many respects they must be regarded as the more reliable that the results are reproducible.

example 1

The mixture tested in this example was composed of:

(A) the dioxide as a 48% emulsifiable concentrate;

(B) Isopropyl-N-benzoyl-N- (3-chloro-4-fluorophenyl) -2-amino-propionate as a 20% emulsifiable concentrate.

Both were commercial products, the dioxide (A) being known herbicides under the protected trade name “BASAGRAN”, the propionate (B) under the protected trade name “BARNON”.

Pots with a diameter of 7 cm, filled with compost, were used, of which a number with 25-30 barley grains each, a further number with 25-30 grains of culture oats (Avena sativa) were sown. When the plants had developed 1 or 1V2 leaves, a solution of the mixture to be tested was sprayed using five different dosages for each of the two species and using a logarithmic sprayer. Mixtures of the two compounds in different proportions were also sprayed in five different dosages.

The evaluation was carried out 11 days after spraying.

The phytotoxicity to the barley and oat plants was assessed visually (barley on a standard scale of 0-9 and oat on a percentage scale where 100 means no growth after spraying). The values obtained, expressed as a percentage, based on the standard values for untreated barley and untreated oats, were analyzed with the computer in order to calculate the doses at which the growth was restricted by 50% for barley and by 90% for wheat. These doses were designated "GID50 barley" or "GID90 oats". The selectivity factor (S.F.) for the respective test compound can be calculated using the following expression:

^ P _ GIDso barley GID90 oats

The selectivity factor represents a comparative measure of the effect of the mixtures or compounds to be tested as a selective herbicide; the greater this selectivity factor, the better the selectivity between the two plant species.

The mixtures used and the results obtained are shown in Table I.

Table I

Ratio GID50 (kg / ha) GID90 (kg / ha) Selectivity factor (B): (A) for (B) for (B) GID50 / barley

Barley oats GID90 oats

0: 1 - -

1: 4 2.12 0.12 18

1: 2 2.48 0.09 28

1: 1 2.81 0.10 28

1: 0.5 3.69 0.09 41

1: 0 3.67 0.14 26

The results show that the dioxide (compound A) alone has no effect on oats and that even when combined with the alanine derivative (compound B), the GID90 oat values are lower than those obtained for compound B alone receives. This leads to the conclusion that component A has some effect which leads to a synergistic result. It can also be seen that the selectivity factor is generally improved rather than worsened.

Example 2

A mixture of the following components was tested:

(A) The dioxide as a 48% emulsifiable concentrate (commercial product, protected name «BASAGRAN») and

(C) Methyl-N-benzoyl-N- (3-chloro-4-fluorophenyl) -2-aminopropionate as a 15% emulsifiable concentrate.

The experiments were carried out as in Example 1, but using wheat instead of barley seeds. The results are shown in Table II.

Table II

Ratio GID10 (kg / ha) GID90 (kg / ha) Selectivity factor (C) :( A) for (C) for (C) GID10 / wheat

Wheat oat GID90 wind oat

0: 1

1: 8 1.00 0.09 11

1: 4 0.72 0.07 10

1: 2 1.01 0.06 17

1: 1 0.84 0.07 12

1: 0 0.62 0.08 8

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Claims (8)

620 097 2nd PATENT CLAIMS 1. Weed killer, characterized in that the herbicidal component consists of the following compounds: (a) 3-isopropyl-1H-2, 1,3-benzthiadiazine (4), 3H-one-2,2-dioxide and (b) an N, N-disubstituted alanine derivative of the general formula: where Y and Z each represent either chlorine or fluorine and X represents oxygen or sulfur, while R represents one of the following groups: a group of the formula —ORj, wherein Rj is a hydrogen atom, a metal salt-forming or an optionally alkyl-substituted ammonium ion, an optionally substituted alkyl, cycloalkyl, aryl, alkenyl or alkaryl group; or a group of the formula -SR2, in which R2 is an optionally substituted alkyl, cycloalkyl, aryl, alkenyl or alkaryl group; or a group of the formula —NR3R4 or -ON = CR3R4, wherein R3 and R4 each represent a hydrogen atom, a hydroxyl group, an optionally substituted alkyl, alkenyl, aryl, alkaryl, heterocyclyl, alkoxy, alkylthio or amino group, or wherein R3 and R4 together represent a polymethylene group which can optionally be interrupted by one or more heteroatoms, with the condition that X cannot be oxygen, Y and Z can be chlorine and R can be ethoxy. 2. Weed killer according to claim 1, characterized in that the component (b) corresponds to the general formula I, in which Z represents a fluorine atom and Y represents a chlorine atom. 3. Weed killer according to claim 1 or 2, characterized in that the N, N-disubstituted alanine derivative (b) has the following general formula: (II), where Y is chlorine, Z is fluorine and R is a hydrogen atom or an alkyl group with up to 6 carbon atoms. 4. Weed killer according to one of the preceding claims, characterized in that component (b) is a compound of formula II, wherein Z is fluorine, Y is chlorine and R is isopropyl. 5. Weed killer according to any one of claims 1-3, characterized in that component (b) is a compound of formula II, wherein Z is fluorine, Y is chlorine and R is methyl. 6. Use of the weed killing agent according to claim 1 for the selective control of wind oat (Avena fatua) in cereal crops, characterized in that the agent is distributed over the area under cereals affected by wind oat. 7. Use of the weed killer according to claim 6 for leaf treatment after emergence of the plants. 8. Use of the weed killer according to claim 6 or 7, characterized in that the agent in which the active ingredient is a mixture of 1 part by weight of alanine derivative (b) and 0.2-25 parts by weight of dioxide (a) , used in an amount of 0.25-2.0 kg / ha. 25th 30th 40 55 60 15