DD151405A1 - HERBICIDAL AGENT - Google Patents

Abstract

The invention relates to a novel herbicidal active ingredient combination consisting of an active compound of the formula I in which Hal is chlorine or bromine, R & ind1! a straight-chain or branched alkyl having 1 to 18 C atoms or phenyl, X is oxygen or sulfur and Y is sulfur, where in the case where X is sulfur, Y can also be oxygen, and one or more compounds of the formula II, in the Hal Bromine or Iodine and R & ind2! Means alkyl having 4 to 10 C atoms, which has a high selective and synergistic action in the control of weeds, especially in cereal and maize crops, and a method for controlling weeds with this combination.

Description

The invention relates to a novel herbicidal combination of active substances which consists of an already known phenylpyridazine derivative and likewise known 3,5-dihalogeno-hydroxynitrile derivatives, and which has a particularly high selective and synergistic action in weed control, and to a method for controlling weeds. in particular of hard-to-control weeds in cereal and maize crops.

Characteristic of the known technical solutions

It is known (AT-PS 326 409) that phenylpyridazines of the general formula I of the formula sheet, in the shark a chlorine or bromine atom, R. a straight-chain or branched alkyl radical having 1 to 18 carbon atoms or the phenyl radical, X is an oxygen or Y is a sulfur atom, wherein in the case that X is an S atom, Y can also be oxygen, have herbicidal properties and are distinguished for many crops, including cereal crops, by a good compatibility.

In particular, the compound O - / "3-phenyl-6-chloro-pyridazinyl- (4) 7-S- (n-octyl) -thiocarbonate (" pyridate ") has been found to be effective as an agent for controlling weeds in cereals and maize crops (Discus et al., Proc. 9th British Weed

Control Conf. 1976, Vol.2, 717) and detects a broad spectrum of weeds.

In practical outdoor use, however, it has been found that some weed species, such as e.g. Stellaria media (chickweed) and Polygonum convolvulus (windweed) only with relatively high drug doses or, as e.g. Papaver rhoeas (poppy), are at all poorly combatted. This is especially the case when the weeds are in an advanced state of development.

It is further known that compounds from the series of 3,5-dihalogeno - ^ - hydroxybenzonitriles have good properties as contact herbicides (Nature, London, 1963, Vol.200, page 28). In particular, the octyl esters of the compound 4-hydroxy-3,5-diiodobenzonitrile ("ioxyniloctanoate") and the compound 4-hydroxy-3,5-dibromobenzonitrile ("bromoxyniloctanoate") are used against postemergence annual broadleaf weeds ( H. Martin, Ch.R. Worthing, "Pesticide Manual" 5th edition 1977, pages 293 and 5k). However, a number of weeds become more resistant with increasing age, so relatively high application rates have to be used to control them. Among these weeds include Galium aparine (Klettenlabkraut) and Galeopsis tetrahit (Arable tooth) (Kurth H: "Chemical Weed Control", Fischer Verlag 3ena, 1975, page 170).

Object of the invention

It has now been found that mixtures of active compounds from the group of phenylpyridazines of the general formula I, in particular the compound 0- / 3-phenyl-6-chloro-pyridazinyl-Cf) _7-S- (n-octyl) thiocarbonate

("Pyridate") with the active ingredients from the series of 3,5-dihalogeno-4-hydroxybenzonitrile, in particular the compounds 4-hydroxy-3,5-dijodbenzonitriloctanoate ("loxyniloctanoate") and ^ -hydroxy-3,5-dibrombenzonitriloctanoate ( "Bromoxyniloctanoate") give a herbicidal efficiency, which is significantly above that efficiency that could be expected due to a merely additive effect of both components. These are

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after a truly synergistic effect, which must by no means be foreseen to this extent and as extremely surprising.

The present invention accordingly provides a herbicidal composition, characterized in that it contains as active ingredient a mixture of one or more compounds of the general formula I of the formula sheet, in the shark a chlorine or bromine atom, R.sup.a straight-chain or branched alkyl radical with 1 to 18 carbon atoms or the phenyl radical, X is an oxygen or sulfur atom and Y is a sulfur atom, wherein in the case that X is an S atom, Y may also be oxygen, with compounds of the general formula II of the formula sheet, in which Hal is a bromine or iodine atom and R _{2 is} an alkyl radical having f to 10 carbon atoms.

Explanation of the essence of the invention

This, beyond a merely additive effect, increased, herbicidal efficiency of these drug mixtures, there are considerable technical advantages, since it is thus possible to significantly reduce the application rates of the individual components per treated area.

Among the compounds according to formula I, the compounds O- / | 5-phenyl-choropyridazinyl-C ^ VS-in-propyl-thiocarbonate, OAJ-phenyl-δ-chloro-pyridazinyl- (4) _7-S- (n -butyl) thiocarbonate, O- / 3-phenyl-6-bromopyridazynil- (4) 7-S- (n-butyl) thiocarbonate and O - / "3-phenyl-6-chloro-pyridazinyl- (4) _7 -S- (n-dodecyl) -thiocarbonate significant increases in activity in combination with compounds of formula II. Particularly effective among the compounds of formula I is the compound O-jO-phenyl-o-chloro-pyridazinyl- ^ f ^ -S-in -octyo-thiocarbonate ("pyridates"), of the compounds of formula II are in particular with ^ -hydroxy-S ^ -dijodbenzonitril-octanoate ("ioxynil-octanoate") and / or with ^ -hydroxy-Sj ^ -dibrombenzonitril-octanoate ("Bromoxynil-octanoate") achieved good results.

The agents according to the invention can be converted into the customary formulations, such as solutions, emulsions, dispersions, powders, pastes and granules. These are prepared in a known manner, e.g. by mixing

-ii rule the active ingredients with extenders, ie liquid solvents and / or solid carriers, optionally with the use of surfactants, emulsifiers and / or dispersants. Suitable solid carriers are essentially: ground natural minerals, such as kaolins, clays, talc and chalk, and ground synthetic minerals, such as finely divided silica and silicates; as emulsifier: nonionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, alkylsulfonates, arylsulfonates and alkylarylsulfonates; as wetting and dispersing agent: Lignin-Sulphite liquors, M ethyl cellulose and Naoleyl-methyltaurid.

The proportions of the compound of the formula I present in the mixture to the compounds of the formula II (phenol equivalents) can vary within a certain range, for example in the ratio of 1: 1.6 to 1: 0.1, mixtures in which the proportion to compounds of formula I predominates, are particularly preferred.

The active compound combination according to the invention can e.g. formulated as a wettable powder or as an emulsion concentrate according to the following recipe:

Active ingredient according to formula I Active ingredient according to formula II

Wetting or dispersing inert fillers or carriers

14-50% by weight 3-20% by weight (based on phenol equivalents) 5-15% by weight ad 100

This formulation is suspended or emulsified in water for use. It may also contain other known active substances, such as herbicides, fungicides or growth regulators. Particularly favorable is a combination with agents from the group of phenoxycarboxylic acids, such. MCPA, CMPP, 2,4-DP and 2,4-D or their salts or esters, since they can be used to combat perennial weeds in one operation.

The compositions according to the invention are used postemergence.

The application rates of the drug combination can be varied within a certain range. They depend on the composition of the drug combination and the nature of the weeds. Usually, the active ingredient of the general formula I is applied in an application rate of 0.25 to 1.0 kg / ha and the active ingredient of the general formula II in an application rate of 0.1 to 0.4 kg / ha.

The use of the agents according to the invention in cereal and maize cultures is particularly preferred, the active compound of the formula I being used at a rate of from 0.5 to 1.0 kg / ha and the active compound of the formula II being used at a rate of from 0.2 to 0, 4 kg / ha is given.

To determine whether a mixture gives additive or synergistic effects, the following formula is usually used:

^{e x + y}

(according to Limpel, LE, PH Schuldt, D. Lamont, 1962, Weed control by dimethyltetrachloroterephthalate alone and in certain combinations, Proc.NEWCC 16: 48-53, based on Gowing, DP 1960, Comments on tests of herbicide mixtures, Weeds 8 : 379-391).

E = herbicidal efficiency to be expected (with additive effect) (% weed killing) after application of A + B at ρ + q kg effort / ha.

X = efficiency (%) when drug A is used with ρ kg / ha Y = efficiency (%) when drug B is used at q kg / ha.

If the experimentally found value for E is above the value calculated according to the above formula, there is a synergism; if the value is lower, an antagonism is given.

From the results of Tables 1 to 5 it is clear that in almost all cases when combining the active ingredients I + II or I + III herbicides

Efficiency (% kill) is significantly higher than expected (purely calculated) values with purely additive effect.

The practical benefit of synergism to the extent shown here is extremely high. As is known, the EWRC evaluation scheme for herbicidal efficiency is based on an approximate exponential function between the efficiency (96 kill) and the respective score (or score) such that in the practical range between 85 and 100 counts 96 kill more significantly differentiated is considered to be in the economically uninteresting range between 0 and 85% mortality (see EEA ERA rating scheme).

Increasing the efficiency in the upper range is therefore much more important than in the lower range. An improvement in the efficiency of, for example, 95% to 100% (+5 96) equates to an improvement by two grading scores, whereas an increase in efficiency eg from 70% to 80% (+10%) corresponds to only one grade level and, moreover, practically little importance has (both 70% and 80 96 kill are still considered insufficient).

As can be seen from the example, however, especially in the range between 85 % and 100% killing, synergistic increases in activity are to be noted in all cases to an economically significant extent.

The example further shows that even at an application rate of 0.25 kg / ha of the compound I (pyridate) and of 0.1 kg / ha of the compound II (ioxyniloctanoates) the herbicidal efficiency of all tested weeds significantly above the effect of the sum the individual components lies. The synergistic effect is particularly evident in this case, it is e.g. in the weeds Galeopsis tetrahit (European tooth), Lamium purpureum (Red nettle) and Veronica hederifoliä (Honorary prize) at +26, +27 and +29 96.

Of great practical importance in the combination of 0.25 kg / ha of the compound I with 0.2 kg / ha of the compound II, the increase in the efficiency over the very difficult to combat ble Galium aparine (Klettenlabkraut)

to 98% kill, which already corresponds to a very good effect according to E.W.R.C. In the combination of 0.5 kg / ha of the compound I with 0.2 kg / ha of the compound II, all weeds, in particular Galium aparine (Klettenlaber) already 100% destroyed with the exception of Polygonum convolvulus (Windenknöterich).

The compound III (Bromoxynil-octanoate) is very similar in its chemical, physical and biocidal properties of the compound II (Ioxynil-octanoate). Accordingly, the synergistic effects also occur in a very similar manner, as can be seen from Tables 4 and 5 .

Embodiment:

The experimental units were rectangular plastic boxes (35 χ 38 χ 7 cm), which were planted with the respective weeds. The following economically significant arable weeds were used for the experiments:

Chenopodium album white goosefoot A Galeopsis tetrahit Field hollow tooth B Galium aparine cleavers C Lamium purpureum Red nettle D Lapsana communis Rain carbon e Lithospermum arvense Lithospermum arvense F Matricaria chamomilla Real chamomile G Papaver rhoeas poppy H Poiygonum convolvulus buckwheat - T Stellaria media chickweed K Veronica heder if olia speedwell L

After the weeds had reached the stage of development to which they are usually treated in crop crops with postemergent herbicides (Galium aparine eg branched, with 3-6 whorled / runner, Lapsana communis at 6 to SBlattstadium, Matricaria chamomilla at 8 to loblatt stage, Stellaria media already branched, developed with 4 to 6 leaf pairs per side shoot, Galeopsis tetrahit 2 to 3 leaf pairs, etc.), the active compounds or drug combinations were sprayed on the weeds in the indicated dosages. The spray mixture amount was uniformly 500 l / ha.

Four weeks after spraying the herbicidal efficiency was detected. The remaining residual weeds were harvested separately according to weed species and their fresh weight determined. The same procedure was followed with the weeds in the untreated comparison boxes.

The residual weeds were treated with the weeds in the untreated

Kistchen set in this way and the respective herbicidal efficiency (96 killing) found. These values were then tested for synergistic effects in the case of the product mixtures using Limpel's formula.

The compound "pyridate" was used in the following composition:

70.0% of the active substance

7.5% Alkyiarylsulfonat-Polyoxyäthylen emulsifier 22.5% solvent

The compounds Ioxynil-octanoate or Bromoxynil-octanoate were used in the following preparation:

more emulsifier Mixture aro material matic Koh bons Ioxynil-octanoate (corresponding to bOO g / l 47.02% 4.38% ad 100% Phenol equivalent) Bromine oxyniloctanoate (corresponding to 400 g / l 51.08% 4.38% ad 100% phenol equivalent

The data on kg / AS / ha in the tables relate to ioxynil resp. Bromoxyniloctanoate to the respective equivalents of free phenol.

active substance A B Table 1 killing e of the weeds i G η% I K L § 1 45 52nd dosage 70 70 in kg AS / ha 75 53 D 65 F 50 H 60 52 82 1 90 89 72 C 76 62 65 70 <! ( O / l-Phenyl-6-chloro- 0.25 100 100 45 100 82 95 10 75 85 pyndazinyl- (4) 7- 0.5 60 66 25 35 45 -S- (n-octyl) thio 1.0 75 100 100 55 72 carbonate 55 40 98 78 70 32 70 95 (Pyridates) = I 72 65 90 75 76 75 4-hydroxy-3,5-diiodo- ο, ι 100 100 50 98 25 100 87 89 90 benzonitrile-octanoate 0.2 33 65 52 92 0.4 67 78 75 100 (Ioxynil octanoate) 42 50 88 67 80 22 65 = 11 68 60 84 92 45 73 4-hydroxy-3,5-di- 0.1 100 100 44 95 22 100 73 75 89 brombenzonitril- 0.2 30 70 55 87 octanoate 0.4 58 80 68 100 77 (Bromoxynil octanoate) = III

-4 * - Table 2

Active ingredients, effort kg AS / ha

I + II

Killing the weeds in 96 DEFGHI

0.25 + 0.1

+ 0.2

found 100 98 87 100 98 95 100 98 92 100 Z5 calculated 89 72 79 73 93 87 85 88 73 86 56 difference + 11 +26 +8 +27 +5 +8 +15 + 10 + 19 + 14 +29

found 100 100 98 100 100 97 100 100 95 100 92 calculated 93 94 87 81 97 92 88 93 91 84 difference +7 +6 +11 + 19 +3 +5 + 12 +7 +4 + 12 +8

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 96 88 100 96 [QQ 100 96 96 95 difference - - +4 + 12 - +4 - - +4 +4 +5 found 100 IQQ 90 100 100 98 100 100 96 100 90 calculated 95 84 84 83 95 89 89 92 77 91 86 difference +5 + 16 +6 + 17 +5 +9 +11 +8 + 19 +9 +4

0.5 + 0.1

+ 0.2

+ 0.4

found 100 100 100 100 100 100 100 100 95 100 100 calculated 97 91 92 88 98 93 91 95 92 93 91 difference +3 +9 +8 + 12 +2 +7 +9 +5 +3 +7 +9

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 97 93 100 97 100 100 91 97 97 difference - _ +3 +7 +3 - +9 +3 +3

Table 3

Active ingredients, effort kg AS / ha

I + II

1.0 + 0.1

+ 0.2

Killing the weeds in% CDEFGH

found 100 100 100 100 100 100 100 100 95 100 100 calculated 100 100 99 100 100 100 99 95 83 96 92 difference _ _ + 1 _ _ - + 1 +5 + 12 +4 +8

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 100 100 100 100 99 97 94 97 95 difference - - - - - - + 1 +3 +6 +3 +5

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 100 100 100 100 100 100 98 99 99 difference _ _ - _ _ _ _ +2 + 1 + 1

Table 4

Active ingredients, effort kg AS / ha

I + III

Killing the weeds in% CDEFGH

0.25 + 0.1

+ 0.2

found 98 95 80 95 100 92 100 85 78 calculated 86 77 72 70 89 86 90 76 69 difference + 12 + 18 +8 +25 + 11 +6 + 10 +9 +9

94

+ 10

found 100 100 94 100 100 95 100 100 95 100 82 calculated 92 82 84 84 95 92 96 89 88- 88 85 difference +8 + 18 + 10 + 16 +5 +3 +4 + 11 +7 + 12 -3

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 91 89 99 95 100 100 90 95 98 difference - - +9 + 11 + 1 +5 - - + 10 +5 +2 found 95 95 92 91 100 97 100 88 95 93 calculated 94 86 83 81 93 89 93 83 73 90 84 difference +1 +9 +9 + 10 +7 +8 +7 +5 + 12 +5 +9

0.5 + 0.1

+ 0.2

+ 0.4

found 100 100 98 100 100 100 100 100 100 90 98 calculated 97 89 90 90 97 94 97 92 81 92 92 difference +3 + 11 +8 + 10 +3 +6 +3 +8 + 19 -2 +6

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 100 94 93 99 95 100 100 91 97 98 difference _ _ +6 +7 + 1 +5 _ _ +9 +3 +2

Table 5

Active ingredients, effort kg AS / ha

+ III

Killing of weeds in% CD E F G H

1.0 + 0.1

+ 0.2

found

calculated

difference

found

calculated

difference

100 100

100

100

100 100

100 100

100 100

100 99

+ 1

95 88 +7

92

80 + 12

92 95 -3

100 100

100 100

100 100

100 100

100 100

100 100

100 100

100 94 +6

100 98 +2

found 100 100 100 100 100 100 100 100 100 100 100 calculated 100 · 100 99 100 100 100 100 94 86 96 95 difference - - + 1 - - - - +6 + 14 +4 +5

E.W.R.C. evaluation scheme:

value number Killing of Effect of a weeds preparation 1 100% excellent 2 97.5% very well 3 95% Well 90% satisfying 5 85% still sufficient 6 75% unsatisfactory 7 65% low 8th 32.5% very low 9 0 none

O-C

Hal

Hal

O-C-R.

I! O

Claims (4)

invention claims 1. A herbicidal composition, characterized in that it contains as active ingredients one or more compounds of the general formula I of the formula sheet, in the shark a chlorine or bromine atom, R. a straight-chain or branched alkyl radical having 1 to 18 carbon atoms or the phenyl radical X is an oxygen or sulfur atom and Y is a sulfur atom, wherein in the case that X is an S atom, Y can also be oxygen, in mixture with compounds of the general formula II of the formula sheet, in the shark a bromine or 3odatom and R _{2 is} an alkyl radical having k to 10 carbon atoms. 2. A herbicidal composition according to item 1, characterized in that the compound O - / "3-phenyl-6-chloropyridazinyl- (4 -) _ 7-S- (n-octyl) thiocarbonate in
Combination with the compound ^ -hydroxy-S ^ -dijodbenzonitril-octanoate and / or ^ -hydroxy-3,5-dibrombenzonitrile-octanoate is applied. 3. A herbicidal composition according to item 1 and 2, characterized in that the mixing ratio of the compound O- / 3-phenyl-6-chloro-pyridazinyl - (^ y7-S- (ri-octyl) -thiocarbonate with the compound 4-hydroxy -3,5-diiodobenzonitrile-octanoate or ^ -hydroxy-S ^ -dibromobenzonitrile-octanoate in a ratio of 1: 1.6 to 1: 0.1, wherein the amounts of Hydroxybenzonitrile are given in phenol equivalents. 4. A method for controlling weeds, characterized in that the cultures are treated after emergence of the plants with a mixture according to claims 1 to 3, wherein the active ingredient of the general formula I in an application rate of 0.25 - 1 kg / ha given is added and the active ingredients 4-hydroxy-3,5-dijodbenzonitril-octanoate or 4-hydroxy-3,5-dibrombenzonitrile-octanoate in an application rate of 0.1 to 0.4 kg / ha. O.Z.669