CH641011A5 - Herbicidal treatment process and compositions for this purpose - Google Patents

Description

The present invention relates to a method for controlling weeds in cereal crops, as well as herbicidal formulations used in this method.

So far, the broad-leaved weed species Matricaria spp has been shown to be particularly resistant to conventional herbicides, causing enormous damage in winter and spring cereal crops such as wheat, barley, oats 40 and rye. Now, the licensee has found that, using a combination of specific known herbicides, this weed species can be controlled with surprisingly high synergism in accordance with the well-known Colby equation ("Weeds", 15, 20-22, 1967). In addition, it has been found that the control of other weed species is very satisfactory using this combination, synergism being again observed in several cases.

Consequently, according to the present invention, a process for combating weeds in cereal fields consists in applying, to these fields and after the emergence of the harvest, a compound of formula I:

O

CII-O-C

55 -J

and one or more compounds of formula II:

xh_

65

Cl-

// w

(II)

O-X-COOH

3

641 Oli where X represents a group - CH (CH3) -, a group - CH2— or a group - (CH2) 3 -; when using a compound of formula II in which X represents a group —CH (CH3) -, the compound of formula I is applied at a rate of 0.25 to 3 kg / ha, while the compound of formula II is applied at a rate of 0.5 to 3 kg / ha; when using a compound of formula II in which X represents a group - CH2—, the compound of formula I is applied at a rate of 0.7 to 2 kg / ha, while the compound of formula II is applied at a rate of 0.7 to 3 kg / ha and, when using a compound of formula II in which X represents a group - (CH2) 3 -, the compound of formula I is applied at a rate of 0.25 to 3 kg / ha and the compound of formula II is applied at a rate of 0.1 to 3.5 kg / ha, the crop not being a crop of spring wheat when a single compound of formula II is used in which X is a group - CH (CH3) -.

In general, the compound of formula I is applied at the rate of 0.7 to 2 kg / ha, while the compound (s) of formula II is (are) applied at the rate of 0.7 to 3 kg / ha Ha.

The compound of formula I is known under the name of Bifenox, the preparation of which is described in British Patent No. 1232368 and the use of which as a herbicide is described in "Proc. N.E. Weed Sci. Conf. ”, 1973, 27, 31.

The compound of formula II in which X is a group —CH (CH3) - is known under the name of Mecoprop.

The compound of formula II in which X is a group —CH2 - is known under the name of M.C.P.A.

The compound of formula II in which X is a group - (CH2) 3 - is known under the name of M.C.P.B.

Literature abounds in documentation concerning Mecoprop, M.C.P.A., M.C.P.B., their salts and their esters, as well as with regard to their preparation and their herbicidal properties.

The compounds of formula II can be used in the form of free acids or also in the form of salts or esters which are not phytotoxic with regard to cereals. Among the salt forms, there may be mentioned, for example, the alkali metal salts, in particular the sodium and potassium salts, as well as the ammonium, alkylammonium and alkanolammonium salts, for example, the salts of ethanolammonium. Among the esters, mention may be made of lower alkyl esters (for example, those containing 1 to 8 carbon atoms), in particular methyl and octyl esters. The use of these salts and esters is within the scope of the present invention.

In the process of the present invention, the compound of formula I (Bifenox) is preferably applied at the rate of 0.7 to 1.5 kg / ha, more preferably at the rate of about 0.75 to 1 kg /Ha. The compound of formula II in which X is a group - CH (CH3) - or a group - (CH2) 3—, that is to say Mecoprop or MCPB, is preferably applied in an amount of 1 at 2 kg / ha. The compound of formula II in which X is a group - CH2—, that is to say the MCPA, is applied, preferably, at a rate of 0.7 to 1.5 kg / ha, better still, at a rate about 0.75 to 1 kg / ha.

The weight ratio between the compound of formula I and the compound (s) of formula II is generally in the range of 1: 4 to 3: 1. When Bifenox is used in combination with Mecoprop or MCPB, the weight ratio between the first and the second is preferably in the range of 1: 3 to 1.5: 1, more preferably, about 1 : 2. When using Bifenox with M.C.P.A., the weight ratio between the first and the second is preferably in the range of 1: 2 to 2: 1, more preferably about 1: 1.

In the case of the compounds of formula II, the weight ratios mentioned above are based on the acid equivalent of these compounds if a salt or an ester is used.

It is preferable to carry out the process of the present invention when the harvest is between the stage of a leaf and the appearance of the second node.

The crops which it is preferable to process by the process of the present invention are winter wheat, spring barley and winter barley.

The compound of formula 1 and the compound or compounds of formula II can be applied together or separately. In the latter case, the period of time between the applications is preferably short, for example 1 d or less. However, it is far better to apply the compounds simultaneously as a single formulation. In order to simplify the preparation, storage and transport, the herbicidal formulations are normally prepared in the form of concentrates intended to be diluted in water to the degree required to obtain the application rates mentioned above. These concentrate formulations can contain 1 to 90%, preferably 15 to 85% by weight of active ingredients associated with one or more inert and non-phytotoxic carriers for these ingredients. These formulations are usually in the form of a wettable powder, an emulsifiable concentrate or also in the form of a suspension or an aqueous solution.

Another aspect of the present invention is herbicidal formulations. Thus, a herbicidal formulation is intended to be used in the process of the invention, optionally after dilution if necessary, this formulation comprising a compound of formula I and one or more compounds of formula II or one of their salts or esters in a weight ratio ranging from 1: 4 to 3: 1 (based on the acid equivalent of the compound or compounds of formula II) together with a carrier or diluent non phytotoxic. Preferred weight ratios are in the ranges indicated above.

According to another distinct aspect of the present invention, there is provided a herbicidal formulation comprising a compound of formula I (indicated above) together with a compound of formula II in which X is a group - (CH2) 3 - or one of its salts or esters in a weight ratio in the range of 1: 4 to 3: 1 (based on the acid equivalent of the compound of formula II) and with a non-phytotoxic carrier or diluent. In this case also, the preferred weight ratios are in the ranges indicated above.

The herbicidal formulations of the present invention include not only so-called concentrate formulations, but also ready-to-use diluted formulations such as tank mixes and liquors for spray application. These diluted formulations are generally prepared by diluting concentrate formulations to the appropriate degree, but can optionally be prepared by separate addition of appropriate amounts of the individual components to an adequate diluent or carrier.

Referring now to the concentrate formulations, the wettable powders consist of an intimate mixture of the active ingredients, one or more inert carriers and one or more suitable surfactants. The inert support can be chosen from attapulgite and montmorillonite clays, in-fusoires soils, kaolins, micas, talcs and purified silicates. Effective surfactants can be found among sulphonated lignins, condensed naphthalenesulfonates and naphthalenesulfonates, alkyl succinates, alkylbenzenesulfonates, alkyl sulfates and nonionic surfactants such as addition of phenol to ethylene oxide. Examples of wettable powders are those having the following composition:

Wettable powders

% in weight

Compound of formula I 1 to 73

Compound of formula II * 1 to 79

Surfactant (s) 1 to 10

Dispersing agent 0 to 10

Bulking inhibiting agent 0 to 10

Inert support (s), to complete to 100

* Based on the acid equivalent.

Emulsifiable concentrates consist of the active ingredients dissolved in one or more suitable solvents, together with a surfactant. Among the suitable solvents are

5

10

15

20

25

30

35

40

45

50

55

60

65

641 Oli

4

may mention, for example, benzenes substituted by an alkyl% by weight group, o-chlorotoluene, heavy aromatic naphthalenes, fumed gjjice 6

glycol ethers and cyclic ketones. Examples of Attapulgite concentrates, to make up to 100

emulsifiable are those having the following composition: Emulsifiable concentrates

% w / v

% in weight

3) Bifenox 10

Mecoprop (diethanolamine salt) 25

Compound of formula I 1 to 55 §ej jg soc [jum of condensed naphthalene sulfonic acids 6

Compound of formula II * there 60 Precipitated silica 10

Surfactant (s) 2 to 10 io Sodium aluminosilicate, to make up to 100

Co-solvent 0 to 40

Solvent, to complete to 100% by weight

* Based on the acid equivalent. 4) Bifenox 30

M.C.P.B. (sodium salt) 45

The aqueous suspensions and solutions consist of the ingredients Sodium Lauryl Sulfate 2

active dients in suspension or in solution in water together Sodium lignosulfonate 3

with any other desired product selected from ten- precipitated silica 5

sio-active, thickening agents, antifreeze agents or Montmorillonite agents, to complete 100 preservation. The suitable surfactants can be chosen from those mentioned above with respect to the wettable powders 20% by weight. ,,. 5) Bifenox 30

When used, the thickening agents are normally M C P A (sodium salt) 30

chosen from natural gums and cellulosic materials ap- Sodium lauryl sulfate 2

properties, while glycols are generally used when sodium lignosulfonate 3

must provide an antifreeze agent. Preservatives can 25 precipitated silica 5

be chosen from a wide range of materials such as diff- Montmorillonite, to complete 100

many antibacterial agents based on parabens, phenol, o-chloro- In each example, the ingredients cresol, phenylmercuric nitrate and formaldehyde are carefully mixed. Among the active agents with the excipients specified in an aqueous suspension mixing equipment, there are, for example, those having the classical composites. Then, in a fluidizing energy mixer, the following tions. 30 ^ roje more the mixture to a granularity lying in the inter-

Aqueous suspensions range from 1 to 10 | a.

% w / v

Compound of formula I 4 to 59

Compound of formula II * 5 at 65 35 ° n prepares the emulsifiable concentrates below containing the

Wetting agent 0 to 10 constituents indicated:

Dispersing agent 0 to 6% w / v

Thickening / suspending agent 0 to 5

Antifreeze agent 0àl5 6) Bifenox 15

Preservative 0 to 2 40 Mecoprop 30

Water, to make up to 100 Calcium dodecylbenzenesulfonate 3

Alkylphenoxypolyoxyethylene-ethanols 3

* Based on the acid equivalent. Isophorone 20

EXAMPLES 6 TO 10

It is better to use aqueous suspensions and powders

Xylene, to complete to 100

emulsifiable concentrates.

The following examples further illustrate the invention. In all these examples, the amounts of Mecoprop, of M.C.P.A. and of M.C.P.B. used are based on the acid equivalent.

wettable in the process of the present invention, because they are 0 / o in weight / volume much less phytotoxic to cereal crops than

7) Bifenox 15

Mecoprop 20 ester

Alkylarylsulfonate 4

50 Polyoxyethylene triglyceride 4

Cyclohexanone 20

Examples 1 to 5 Orthochlorotoluene, to complete 100

The following wettable powders are prepared, each containing 0/0 w / v the ingredients indicated:

55 8) Bifenox 10

% by weight MeCoProp 25

1) Bifenox 20 Amine salt of dodecylbenzenesulfonic acid 3 Mecoprop (potassium salt) 40 Polyoxyethylenesorbitol fatty esters 4 Sodium laurylsulfate 3 Isophorone 15 Sodium lignosulfonate 3 60 Heavy aromatic naphtha, to supplement 100 Precipitated silica 8

Kaolin, to complete 100% by weight / volume o 9) Bifenox 20

/ "in P ° M.C.P.B. (mixed butyl esters) 30

2) Bifenox 20 ss Calcium dodecylbenzenesulfonate 3 Mecoprop (sodium salt) 27 Alkylphenoxypolyoxyethylene-ethanols 4 Ethoxylated alkylphenol 4 Isophorone 30 Lignosulfonate 3 Orthochlorotoluene, to complete 100

5

641 Oli

% w / v

10) Bifenox 20

M.C.P.A. 20 Calcium dodecylbenzenesulfonate 3 Alkylphenoxypolyoxyethylene-ethanols 4 5

Isophorone 30

Orthochlorotoluene, to complete 100

The active ingredients are added to the appropriate solvent (s) while stirring and optionally while heating in order to facilitate the dissolution of the active ingredients. Next, the surfactants are added. The solutions are then filtered to remove insoluble impurities.

Examples 11 to 13

The following aqueous suspensions containing the indicated components are prepared:

% in weight

11) Bifenox 30 M.C.P.A. (amine salt) 30 (Ethyl) hydroxyethylcellulose 0.2 20 Lignosulfonate 3 Propylene glycol 2 Water, to make up to 100

25

% in weight

12) Bifenox 20 M.C.P.B. (amine salt) 35 Hydroxyethylcellulose 0.2 Amine ethoxylate 3 30 Water, to make up to 100

% in weight

13) Bifenox 25

Mecoprop (amine salt) 50

Hydroxyethylcellulose 0.5

Esterphosphate 3

Ethylene glycol 2

Water, to make up to 100

The following examples serve to illustrate the synergistic effect exerted by the process of the invention.

Example 14

Several trials were carried out on winter wheat fields and one trial on a spring barley field in soils of sand and clay potting soil. Using a sprayer on the back, tank mixes were applied in a volume of 300-800 L / ha. The stage reached by the crops at the time of application was between the start of tillering and the stage at which the second node was visible. Visual herbicide activity assessments were performed two to fifteen weeks after application using the Barratt and Horsfall (1945) assessment system.

The table below shows the average of the results obtained in terms of percentage of control of the weed species Matricaria spp for the individual herbicides Bifenox, Mecoprop and MCPA, as well as for the combinations of tank mixes of Bifenox + Mecoprop and Bifenox + MCPA, while also indicating the control value evaluated by the Colby formula for the additive effect. The concentrates from which the aqueous spray liquors were formed were an 80% wettable powder of Bifenox, a 55% aqueous solution of Mecoprop and a 40% aqueous solution of M.C.P.A.

Board

Percentage of control

Dosing rate

(kg / ha)

Observed

Colby's formula

Bifenox

1.0

16.1

None

Bifenox

1.5

25.5

None

Bifenox

2.0

40.3

None

M.C.P.A. (amine salt)

0.8

38.5

None

M.C.P.A. (amine salt)

1.6

64.8

None

Mecoprop (amine salt)

2.0

54.8

None

Bifenox + M.C.P.A. (amine salt)

1.0 + 0.8

85.1

48.4

Bifenox + M.C.P.A. (amine salt)

1.5 + 0.8

93.4

54.2

Bifenox + M.C.P.A. (amine salt)

2.0 + 1.6

95.3

79.0

Bifenox + Mecoprop (amine salt)

1.0 + 2.0

86.0

62.1

Bifenox + Mecoprop (amine salt)

1.5 + 2.0

89.0

66.3

Therefore, from the table above, it can be seen that an authentic synergistic effect is observed when adopting the process of the present invention.

There was a slight burn on the crop which then germinated on the stem.

In addition to the excellent control they have over the Matricaria spp weed, the above tank mixtures have also, in separate trials, exercised excellent control (over 80%) over the following weed species: Anethum gra-veolens, Capsella bursa-pastoris, Centaurea cyanus, Fumaria officina-lis, Lamium amplexicaule, Papaver rhoeas, Silene spp and Stellaria media.

In addition, the combination Bifenox + M.C.P.A. exercised good control (more than 80%) on weeds of the following species: Angallis arvensis, Chenopodium album, Polygonum aviculare, Ranunculus arvensis, Ranunculus repens, Raphanus raphanistrum,

Rumex crispus, Sinapis arvensis, Sonchus arvensis and Veronica hederifolia.

55 In addition, the Bifenox + Mecoprop combination exerted good control (more than 80%) on the Galium aparine species.

Example 15

The greenhouse test described below was carried out to determine the efficacy of the Bifenox 4- M.C.P.B.

Process

Seeds-. Galium aparine

Matricaria recutita 65 Veronica persica

Planting: 0.5 cm deep (Matricaria spp: slight overlap)

Temperature! Lighting ', greenhouse (cold)

641 Oli

6

Watering: as required Fertilization: none

Type of experiment: block taken at random (four replicas) Dimensions of treated lots: 10 x 10 cm pots Soil texture: potting soil

Application equipment: micro-sprayer with single nozzle; band width: 50 cm;

applied volume: 50 ml / m2.

Weed stage at application: 3 to 5 actual leaves

The table below shows the average of the results obtained in terms of percentage of control of the weed species, together with the control value evaluated according to the Colby formula. For the species Veronica persica, a visual control assessment was performed. For the other two species, we took the weight of recent shoots.

The Bifenox from which the spray liquor was formed, was an 80% wettable powder, M.C.P.B. was a 48% aqueous solution, while the combination was a tank mix.

Application rate (kg / ha)

Percentage control of weed species

Matricaria spp

Galium aparine

Veronica persica

Observed

Next Colby

Observed

Next Colby

Observed

Next Colby

Bifenox

0.75

56.5

None

62.5

None

77.0

None

M.C.P.B.

1.0

7.5

None

0.0

None

73.0

None

M.C.P.B.

1.5

2.4

None

0.0

None

78.0

None

Bifenox + M.C.P.B.

0.75 + 1.0

73.0

60.0

72.1

62.5

100.0

94.0

Bifenox + M.C.P.B.

0.75 + 1.5

82.0

57.5

78.3

62.5

100.0

96.0

Therefore, from the table above, it can be seen that an authentic synergistic effect is observed when adopting the process of the present invention.

Example 16

This example further illustrates the synergistic effect of the Bifenox + Mecoprop combination when used to control the broadleaf weed Matricaria spp.

Winter wheat was sown in France in October at a depth of 3 cm and at a rate of 150 kg / ha. The crop was left to grow untreated until the following March, when the crop had reached growth stage 4-5 [see “Plant Pathol.”, 3,128-9 (1954)].

Bifenox and Mecoprop were then applied separately and in combination as a tank mix by spraying them on the area in which the crop was growing, using a sprayer mounted on the back, at a volume of 3001 / h. The determinations (weed control tests) were performed two to five weeks after application.

35

40

Applied dosage

Percentage

(g / ha)

control

weed

Matricaria spp

Bifenox

1000

6

Bifenox

1500

15

Bifenox + Mecoprop

1000 + 2000

87

Bifenox + Mecoprop

1500 + 2000

88

Mecoprop

2000

50

R

Claims (21)

641 Oli 2 1. Method for combating weeds in a cereal field, characterized in that it consists in applying, to this field and after the emergence of the harvest, a compound of formula I: 0 ch3o-c and one or more compounds of formula II: CH. Cl / \ s O-X-COOH (ii) or one or more esters or salts thereof, where X represents a group - CH (CH3) -, a group - CH2— or a group - (CH2) 3 -. 2. Method according to claim 1, characterized in that, when only one compound of formula II is used in which X is a group - CH (CH3) -, it is applied to a crop other than a spring wheat crop. 3. Method according to claim 1, characterized in that, when-X is a group - CH (CH3) -, the compound of formula I is applied at a rate of 0.25 to 3 kg / ha and the compound of formula II is applied at a rate of 0.5 to 3 kg / ha. 4. Method according to claim 1, characterized in that, when a compound of formula II is used in which X is a —CH2— group, the compound of formula I is applied at a rate of 0.7 to 2 kg / ha and the compound of formula II is applied at a rate of 0.7 to 3 kg / ha. 5. Method according to claim 1, characterized in that, when a compound of formula II is used in which X is a group - (CH2) 3 -, the compound of formula I is applied in an amount of 0.25 to 3 kg / ha, while the compound of formula II is applied at a rate of 0.1 to 3.5 kg / ha. 6. Method according to one of claims 1 to 5, characterized in that the compound of formula I is applied in an amount of 0.7 to 2 kg / ha, while the compound or compounds of formula II is (are) applied ^) at a rate of 0.7 to 3 kg / ha. 7. Method according to one of claims 1 to 6, characterized in that the compound of formula I is applied in an amount of 0.7 to 1.5 kg / ha. 8. Method according to one of claims 3 or 5, characterized in that the compound of formula II is applied in an amount of 0.7 to 1.5 kg / ha. 9. Method according to claim 8, characterized in that the compound of formula II is applied at a rate of 0.75 to 1 kg / ha. 10. Method according to claim 4, characterized in that the compound of formula II is applied at a rate of 0.7 to 1.5 kg / ha. 11. Method according to one of claims 3 or 5, characterized in that the weight ratio between the compound of formula I and the compound of formula II is in the range from 1: 3 to 1.5: 1. 12. Method according to claim 4, characterized in that the weight ratio between the compound of formula I and the compound of formula II is in the range from 1: 2 to 2: 1. 13. Method according to one of claims 1 to 12, characterized in that the harvest is a harvest of winter wheat, spring barley or winter barley. 14. Method according to one of claims I to 13, characterized in that a liquor formed on the crop is sprayed by adding water to a formulation of an aqueous suspension or of a wettable powder containing the compounds meeting formulas I and II. 15. Method according to one of claims 1 to 14, characterized in that the processing of the harvest takes place when it has reached a stage lying between that of a leaf and the appearance of the second node. 16. Method according to one of claims 1 to 15, characterized in that the compound of formula II is a salt or a non-phyto-toxic ester with respect to cereal crops. 17. As a means for carrying out the process of claim 1, herbicidal composition comprising a compound of formula I and a compound of formula II, the weight ratio between the compound of formula I and the compound of formula II is lying in the range of 1: 4 to 3: 1. 18. Composition according to Claim 17, characterized in that the composition contains the compound of formula II in which X 15 is a group - CH (CH3) -. 19. Composition according to Claim 17, characterized in that the composition contains the compound of formula II in which X is a group - CH2 -. 20. Composition according to claim 17, characterized in that That the composition contains the compound of formula II in which X is a group - (CH2) 3—. 21. Composition according to one of claims 17 to 20, characterized in that the composition is in the form of an aqueous suspension or a wettable powder. 22. Composition according to one of Claims 17 to 21, characterized in that the compound of formula II is a salt or a non-phytotoxic ester with regard to cereal crops.