ES2594177B2 - Herbicidal mixture - Google Patents

Abstract

The present invention provides a synergistic herbicidal mixture comprising iodosulfuron-methyl (compound I) or its salts, florasulam (compound II) or its salts and diflufenican (compound III). The present invention also relates to a method for controlling weeds in spring and winter cereal crops by applying said mixture.

Description

DESCRIPTION

Herbicidal mixture 5 Field of the invention

This invention belongs to the field of crop protection, and specifically refers to a synergistic herbicidal mixture comprising iodosulfuron-methyl or its salts, florasulam or its salts and diflufenican, and to the preparation and use of said mixture for the control of Weeds in spring and winter cereal crops.

Background of the invention

In the area of crop protection, the use of an active substance for the control of weeds can become increasingly difficult over time, due to the appearance of resistance in relation to the herbicide used. This leads to a loss of efficiency in the control of weeds and, consequently, a loss in profitability and crop yield.

20 A very well known and widely used way to address this problem is to use a combination of different active substances with different biochemical mechanisms of action.

However, the combination of a plurality of active substances frequently causes problems of physical or biological incompatibility, which can result in, for example, the lack of physical stability of the formulation, the degradation of one or more active substances over time. , the antagonism in terms of biological efficacy or phytotoxic effects in the crop.

The compound (I), iodosulfuron-methyl (IUPAC: 4-iodo-2 - [(4-methoxy-6-methyl-1,3,5-triazin-2- yl) carbamoylsulfamoyl] methyl benzoate) whose structural formula is:

image 1

CH3

^ N

N

OR

CH3

(I)

It is an active herbicidal substance described in European Patent EP 0574418.

5 The iodosulfuron-methyl is preferably used in the form of its sodium salt (iodosulfuron-methyl-sodium), which has the formula (la):

image2

CH3

XH,

OR

N

(the)

10 Iodo sulfuron-methyl-sodium is a sulfonylurea that acts by inhibiting the essential amino acid biosynthesis of susceptible plants through the inhibition of the enzyme acetolactate synthase (ALS).

Its early use after outcropping (with respect to both cultivation and weeds) in wheat is well known. Controlled weeds are roots (Lolium rigidum), wild oats (Avena spp), annual Phalaris (Phalaris paradoxa) and several broadleaf weeds.

The compound (II), florasulam (IUPAC: 2 ', 6', 8-trifluoro-5-methoxy [1,2,4] triazolo [1,5-c] pyrimidin-2- 20 sulfonanilide), disclosed in European patent EP 0343752, has the following structural formula:

image3

OR

XCH3

(II)

Florasulam is a triazolopyrimidinsulfonanilide used after the outcrop in cereals, for the control of broadleaf weeds, which acts by inhibiting acetolactate synthase (ALS).

5 The compound (III), diflufenican, (IUPAC: 2 ', 4'-difluoro-2- (a, a, a-trifluoro-m-

tolyloxy) nicotinanilide), disclosed in European patent EP 053011, has the following structural formula:

Diflufenican is a pyridinecarboxamide that can be used before or after the outcrop in cereals to control broadleaf weeds and that acts by inhibiting phytoene dehydrogenase, a key enzyme in carotenoid biosynthesis, which are the pigments responsible for light absorption for Photosynthesis

There are patent documents that refer to the use of the active substances mentioned above in the composition of herbicidal mixtures:

European Patent EP 0831707 B1 refers to combinations of esters of 4-iodo-20 2 - [(4-methoxy-6-methyl-1,3,5-triazin-2-yl) carbamoylsulfamoyl] benzoic acid, in particular iodosulfuron - methyl and its salts, with another active substance selected from a group that includes diflufenican. The patent discloses an example of a synergistic action against Lolium multiflorum, in which the addition of 13 g / ha of diflufenican (which up to a dose of 25 g / ha showed no herbicidal activity) at 10 g / ha of methyl iodosulfuron provided a 25-fold increase in weed control from 60% to 98%, which could only be achieved using 20 g / ha of methyl iodosulfuron.

European patent EP 2033521 B1 refers to mixtures of iodosulfuron-methyl and its salts with florasulam. The patent discloses an example of a synergistic action against Veronica 30 hederifolia, in which the addition of 2.5 g / ha of sodium methyl iodosulfuron (which alone did not show

image4

F

(III)

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herbicidal activity) at 4 g / ha of florasulam resulted in an increase in efficacy from 60% to 65%.

Patent application EP 2095712 A1 refers to combinations of diflufenican with florasulam. The patent presents an example of synergistic action against Lolium multiflornm, in which neither the use of 9 g / ha of diflufenican nor the use of 0.5 g / ha of florasulam showed herbicidal activity, but the combination of 9 g / ha of diflufenican with 0.5 g / ha of florasulam resulted in an efficiency of 30%.

Patent application WO 2003/073854 refers to combinations of ternary herbicides comprising mesosulfuron, iodosulfuron-methyl and a third component selected from a list of 57 active substances comprising florasulam and diflufenican.

None of the prior art documents disclose the mixture of active substances (I), (II) and (III).

There is a need for mixtures that allow a broader weed control, especially for the less sensitive, with an application rate as low as possible in order to optimize its toxicological, ecotoxicological and environmental impact, and with several applications that give as a result an economic solution for the user.

Summary of the invention

The invention relates to a new synergistic herbicidal mixture comprising iodosulfuron-methyl or its salts, florasulam or its salts and diflufenican.

In one embodiment of the invention, the concentration range of iodosulfuron is from 4.0% m / m to 6.3% m / m, the concentration range of florasulam is from 1.6% m / m to 2.5% m / m, and the diflufenican concentration range is from 32% m / m to 50% m / m.

In a preferred embodiment of the invention, the herbicidal mixture comprises 5% m / m of iodosulfuron, 2% m / m of florasulam and 40% m / m of diflufenican.

The mixture according to the invention may further comprise a protector, cloquintocet-mexyl (IUPAC: (5-chloroquinolin-8-yloxy) 1-methylhexyl acetate).

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In one embodiment of the invention, the concentration range of cloquintocet-mexyl is from 8.0% m / m to 12.5% m / m.

The invention also relates to the use of said mixture for the control of weeds in spring and winter cereal crops (hard and soft wheat, barley, oats, triticale and rye) selected from the group comprising Anagallis arvensis, Anthemis spp., Galium aparine, Lolium multiflorum, Lolium rigidum, Matricaria chamomilla, Papaver rhoeas, Picris echioides, Poa annua, Rumex crispus, Sinapis arvensis, Stellaria media and Veronica spp.

The invention also relates to a method for controlling weeds in spring and winter cereal crops (hard and soft wheat, barley, oats, triticale and rye), characterized in that it comprises a stage of applying on weeds or on the ground on which they grow a mixture of methyl iodosulfuron or its salts, florasulam or its salts and diflufenican.

In one aspect of the invention, the process is characterized by applying 7.5 g / ha to 10g / ha of iodosulfuron; from 3 g / ha to 4 g / ha of florasulam and from 60 g / ha to 80 g / ha of diflufenican.

Detailed description of the invention

The aim of the present invention is to provide a mixture of herbicidal active substances with high efficacy in the control of weeds in spring and winter cereal crops (hard and soft wheat, barley, oats, triticale and rye) selected from the group comprising Anagallis arvensis, Anthemis spp., Galium aparine, Lolium multiflorum, Lolium rigidum, Matricaria chamomilla, Papaver rhoeas, Picris echioides, Poa annua, Rumex crispus, Sinapis arvensis, Stellaria media and Veronica spp.

Surprisingly, it was found that through the combination of iodosulfuron-methyl (compound I) or its sodium salt (compound la) with florasulam (compound II) and diflufenican (compound Ill), a synergistic effect on biological efficacy is observed, giving as The result was an unexpected increase in effectiveness compared to the effectiveness of each of the active ingredients.

This synergistic effect allows lower application rates or an increase in action

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herbicide with the same application rates, which results in an economically advantageous procedure for the user, and which is also more favorable from an ecological point of view.

Unless otherwise stated, all concentrations of active substances referred to in this application are expressed as mass percentage (% m / m).

For the purpose of establishing the concentration of active substance in the mixture and the rate at which it will be used per hectare, the active substance iodosulfuron-methyl (I) or its sodium salt (la) is expressed as iodosulfuron, taking into account that 5.00 g of iodosulfuron correspond to 5.14 g of iodosulfuron-methyl or 5.36 g of iodosulfuron-methyl sodium.

In one embodiment of the invention, the iodine sulfur concentration range is from 4.0% to 6.3%, the florasulam concentration range is from 1.6% to 2.5%, and The diflufenican concentration range is from 32% to 50%.

In a preferred embodiment of the invention, the herbicidal mixture comprises 5% iodosulfuron, 2% florasulam and 40% diflufenican.

The mixture according to the invention can also comprise a protector to prevent the phytotoxic effect on the crops to be protected, without a significant influence on the herbicidal action on weeds to be chemically controlled. In the present invention, the antidote used is cloquintocet-mexyl (IUPAC: (5-chloroquinolin-8-yloxy) 1-methylhexyl acetate).

In one embodiment of the invention, the concentration range of cloquintocet-mexyl is from 8.0% to 12.5%.

The mixture according to the invention may be in the form of a wettable powder (WP), water dispersible granules (WG), an aqueous suspension (SC) or an oil suspension (OD).

The formulations are prepared in a known manner, for example, by mixing the active substances with the other coformulants selected from dispersants, wetting agents, disintegrating agents, stabilizers, pH and viscosity modifiers,

charges and combinations thereof.

Preferred dispersants are, for example, sodium or calcium lignosulfonates (Borresperse® Ca, Borresperse® Na or Ufoxane® 3A, commercially available from Borregaard), 5 sodium-formaldeddo naphthalenesulfonate condensates (Supragil® MNS / 90 commercially available from Rhodia) , sodium phenylsulfonates (Supragil® GN, commercially available from Rhodia), ethoxylated and / or propoxylated triestyrylphenols (Soprophor® BSU, Soprophor® S / 40, Soprophor® TSP, Soprophor® 4D384, commercially available from Rhodia) and polycarboxylates (Geropon® T36, commercially available from Rhodia).

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Preferred wetting agents are, for example, sulphosuccinates (Geropon® SDS, commercially available from Rhodia) and alkylnaphthalenesulfonate (Supragil® WP, commercially available from Rhodia, or Morwet® IP, commercially available from AkzoNobel) salts.

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Disintegrating agents are, for example, ammonium sulfate and anhydrous sodium acetate.

The formulations may also contain pH modifiers (such as, for example, citric acid) and fillers (for example, caolm or silica).

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The application rates of the mixture according to the invention are from 7.5 g / ha to 10 g / ha of iodosulfuron, from 3 g / ha to 4 g / ha of florasulam and from 60 g / ha to 80 g / ha of diflufenican.

25 Formulation example

As an example, a formulation in the form of water dispersible granules (WG) is carried out using the following composition and procedure:

 Component

 % m / m

 Iodosulfuron-methyl-sodium (compound la), equivalent to 5.0% of iodosulfuron

 5.4

 Florasulam (compound II)

 2.0

 Diflufenican (Ill compound)

 40.0

 Cloquintocet-mexyl

 10.0

 Morwet® IP (sodium isopropylnaphthalenesulfonate)

 1.0

 Supragil® MNS / 90 (sodium naphthalene sulfonate-formaldehyde condensate)

 3.0

 Geropon® T36 (sodium polycarboxylate)

 6.0

 Ufoxane® 3A (sodium lignosulfonate)

 6.0

 Sipernat® 22S (silica)

 2.0

 Anhydrous sodium acetate

 15.0

 Doric Acid

 1.5

 Caolm

 Up to 100%

Compounds I, II, III, and cloquintocet-mexyl are mixed and subsequently ground in a jet mill, until a sufficiently fine particle size is obtained (approximately 95% of the particles below 10 ^ .m) .

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The above mixture is added to the remaining constituents listed in the table above, and all components are mixed in a suitable mixer (eg Nautamix mixer).

10 Water (5-20% of the mass of solids) is added to the previous mixture in order to form a homogeneous "paste", which is then fed into a "basket" type extruder, where force the material through a perforated sieve (0.7 mm to 1 mm in diameter) using extrusion vanes.

15 Wet granules from the extruder press are fed to the spheronizer, where a rotating plate produces collisions of the granules against the walls of the equipment and against other granules, resulting in their plastic deformation, forming spheres.

The resulting product is dried with a stream of hot air in a fluidized bed dryer 20.

Alternatively, the combination of the active substances according to the invention can be presented, for example, in the form of wettable powders, suspensions in water or oil or emulsions, applied by spraying after dilution with water.

The formulation is applied by diluting it in water and spraying a volume of from 200

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up to 400 liters of the resulting suspension or emulsion per hectare. Synergistic effect

To quantify the synergistic effect resulting from the association of active substances, the method described by Colby (Colby, SR, "Calculating synergistic and antagonistic response of herbicide compositions", Weeds 15, pages 20-22, 1967) was used, according to which the expected efficiency (EE) for the mixture of the active ingredients, determined according to Colby's formula:

EE = x + y - (xy) / 100

in which:

- EE is the expected% efficiency using the mixture of active substances A and B at concentrations a and b;

- x is the% efficiency using active substance A at concentration a;

- and is% effective using active substance B at concentration b; It is compared with the experimentally observed efficacy.

For a mixture of three active substances A, B and C, the reference mentioned above presents a modification of the Colby formula according to which the expected efficacy (EE) is determined by:

EE = x + y + z - (xy + xz + yz) / 100 + (xyz) / 10000

in which:

-x and y are as defined above;

-z is% effective using active substance C at concentration c;

- EE is the expected% efficiency using the mixture of active substances A, B and C at

concentrations a, b and c;

If the observed efficiency (E) exceeds the expected (calculated) (EE), the mixture shows a synergistic effect.

The applicant carried out tests under controlled conditions in which the results of the application of each of the active substances and the ternary mixture obtained were evaluated according to the example of formulation on Galium aparine and Papaver rhoeas.

10 The tests were carried out in a greenhouse with controlled temperature, humidity and lighting, in order to simulate days with 16 hours of light. Weeds were germinated in 15 cm diameter pots placed randomly in the greenhouse, they were relocated 14 days after application in order to minimize variations in weed growth conditions.

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The treatments were carried out by diluting the formulations in water and applying the aqueous suspensions thus obtained by spraying at a rate of 200 l / ha.

The efficacy results were evaluated 28 days after the application of the treatments.

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The test results were treated using the formulas above and are shown in Tables A and B (for reasons of mathematical treatment the efficiencies of 0% became 0.1%).

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TABLE A

 Efficacy against Galium aparine after 28 days

 Active substance

 Substance rate Effectiveness (%)

 active, g / ha Observed Expected

 Florasulam (II)

 2.0 0.1%

 Methyl iodo sulfuron (I)

 5.0 17%

 Diflufenican (III)

 40.0 25%

 I + II + III

 5.0 + 2.0 + 40.0 45.3% 37.8%

TABLE B

 Efficacy against Papaver rhoeas after 28 days

 Active substance

 Substance rate Effectiveness (%)

 active, g / ha Observed Expected

 Florasulam (II)

 1.0 35%

 Methyl iodo sulfuron (I)

 2.5 52%

 Diflufenican (III)

 20.0 10%

 I + II + III

 2.5 + 1.0 + 20.0 77% 71.9%

Twenty-eight days after treatment, the observed efficacy was, in both cases, superior to the expected efficacy in approximately 8%. Therefore, it can be concluded that the mixture according to the invention has a synergistic effect that results in an unexpected increase in weed-fighting efficiency in spring and winter cereal crops.

Claims (8)

1. Synergistic herbicidal mixture characterized in that it comprises a group of active substances consisting of methyl iodosulfuron or its salts, florasulam or its salts and 5 diflufenican. 2. Herbicidal mixture according to claim 1, characterized in that: - the concentration range of iodosulfuron is from 4% m / m to 10 6.3% m / m; - the concentration range of florasulam is from 1.6% m / m to 2.5% m / m; 15 - the diflufenican concentration range is from 32% m / m to 50% m / m. 3. Herbicidal mixture according to claims 1 or 2, characterized in that it also comprises cloquintocet-mexyl. twenty 4. Herbicidal mixture according to claim 3, characterized in that the concentration range of cloquintocet-mexyl is from 8.0% m / m to 12.0% m / m. 5. Herbicidal mixture according to claim 2, characterized in that it comprises the 5.0% m / m of iodosulfuron, 2% m / m of florasulam and 40% m / m of diflufenican. 6. Use of the herbicidal mixture according to any one of claims 1 to 5 for the control of weeds in spring and winter cereal crops (hard and soft wheat, barley, oats, triticale and rye) selected from the group comprising 30 Anagallis arvensis, Anthemis spp., Galium aparine, Lolium multiflorum, Lolium rigidum, Matricaria chamomilla, Papaver rhoeas, Picris echioides, Poa annua, Rumex crispus, Sinapis arvensis, Stellaria media and Veronica spp. 7. Procedure for weed control in spring cereal crops 35 and winter (hard and soft wheat, barley, oats, triticale and rye), characterized because it includes a stage of applying on weeds or on the ground on which they grow a mixture of methyl iodosulfuron or its salts, florasulam or its salts and diflufenican. 8. Method according to claim 7, characterized by the application of 7.5 g / ha to 5 g / ha of iodosulfuron; from 3 g / ha to 4 g / ha of florasulam and from 60 g / ha to 80 g / ha of Diflufenican