FR3046906A1 - HERBICIDE MIXTURE COMPRISING IODOSULFURONE-METHYL OR ITS SALTS AND FLAZASULFURONE - Google Patents

Abstract

The present invention relates to a herbicidal mixture comprising iodosulfuron-methyl or the salts thereof and flazasulfurone, and a method for controlling weeds in olive and vine crops.

Description

HERBICIDE MIXTURE COMPRISING IODOSULFUR-METHYL OR ITS SALTS AND FLAZASULFURONE

Field of the invention

The present invention relates to a herbicidal mixture comprising iodosulfuron-methyl or its salts and flazasulfurone, and its use in the context of crop protection.

Prior Art of the Invention

Compound (I) iodosulfuron-methyl (IUPAC nomenclature [International Union of Pure and Applied Chemistry]: 4-iodo-2- [3- (4-methoxy-6-methyl-1,3,5 triazine-2-yl) ureidossulfonyl] methyl benzoate), having the structural formula:

(I) is a herbicidal substance described in European Patent EP 0574418.

The sodium salt of iodosulfuron-methyl (iodosulfuron-methyl-sodium) having the structural formula (Ia) is preferably used:

(la) Iodosulfurone-methyl-sodium is a sulfonylurea that acts to inhibit the biosynthesis of essential amino acids in susceptible plants through the inhibition of the enzyme acetolactate synthase (ALS).

The dosage of the active substance of iodosulfuron-methyl (I) or its sodium salt (Ia) is expressed in the present invention for the purpose of calculating the proportions of the active substances in the mixture and the amount to be used by hectare, iodosulfurone (Ib),

(Ib) in which 493.2 g of iodosulfurone correspond to 507.2 g of iodosulfuron-methyl or 529.2 g of iodosulfurone-methyl-sodium.

The compound (II) of flazasulfurone (IUPAC nomenclature: (1- (4,6-dimethoxypyrimidin-2-yl) -3- (3-trifluoromethyl-2-pyridile sulfonyl) urea] has the following structural formula:

(II)

Flazasulfurone is also a sulfonylurea that acts to inhibit the biosynthesis of essential amino acids in susceptible plants through the inhibition of the enzyme acetolactate synthase (ALS), which is involved in the synthesis of amino acids that are leucine, isoleucine and valine. It was first described in 1985 by Ishihara Sangyo Kaisha, Ltd. (EP 0184385).

There are some patents concerning sulfonylurea formulations.

The application WO 2002 017718 relates to a process for producing a solid formulation containing a sulfonylurea or a salt thereof, optionally another herbicide and at least one adjuvant, which process comprises the steps of forming a suspension in water containing the formulants, adjust the pH of the suspension to a value between 6.5 and 8

and drying the suspension to obtain a solid formulation.

Application WO 2006 098156 discloses a suspension comprising a sulphonylurea or a salt thereof, at least one surfactant chosen from sorbitol esters of alkoxylated fatty acids and sorbitan esters of fatty acids and an immiscible inert agent in water.

The application WO 2007 027863 relates to liquid formulations comprising 0.1 to 20% of sulfonylureas, 0 to 40% of other active agents other than sulfonylureas, 0.1 to 10% of lignosulfonates, 0 to 99.8% of esters. of fatty acids of C 1 -C 4 alcohols and 0 to 20% of other formulants.

The application WO 2007 119435 relates to the incorporation of a polyalkoxylated phosphate ether alkyl or a salt thereof in order to improve the biological efficiency and the reduction of the sulfonylurea dosage to be used.

However, none of the prior art documents contain any reference or suggestion regarding the mixing of iodosulfurone and flazasulfurone.

Detailed description of the invention

The development of formulations containing various active substances for a wide variety of purposes, such as the management of the development of resistant biotypes, the broadening of the spectrum of biological action, the need to avoid successive applications of plant protection products, etc. is a common practice in the field of crop protection. In general, users prefer liquid formulations because of the ease of measurement, syrup preparation, dilution and spraying.

Surprisingly, it has been found that the application at the beginning of post-emergence on the olive or vine cultures of a mixture of iodosulfurone-methyl-sodium and flazasulfurone has made it possible to obtain results in the field of efficacy in the control of adventitia higher than expected, taking into account the efficiency observed for each of the active substances, which is indicative of a synergistic behavior presented by the mixture for each of the active substances.

"Early post-emergence application" means application of the herbicide to permanent crops following the germination of weeds to the 2-3 leaf stage.

The weeds concerned by the present invention are, for example, herbaceous plants of the family of:

Amaranthacées for example the reflected amaranths (Amaranthus retroflexus L.), the amaranth hybrid (Amaranthus hybridus L.);

Caryophyllaceae, for example the morgeline (Stellaria media (L.) Will.);

Compositae, for example the Barcelona fleabane (Conyza albida Sprengel), the Buenos Aires flea beetle (Conyza bonariensis (L.) Cronq), the marigold (Calendula arvensis L.) / Chamomile chamomile chamomile (Matricaria chamomilla L.), the market garden sow-thistle (Sonchus oleraceus L.);

Crucifers, for example the Shepherd's Wheel (Capsella bursa-pastoris L.), (Diplotaxis cathotica (L.) DC), Wild Mustard (Sinapis arvensis L.), Ravenella (Raphanus raphanistrum L.);

Chenopodiaceae, for example, white alanine (Chenopodium album L.);

Geraniaceae, for example, the crane-billed crane {Erodium malacoides (L.) L'Her.);

Labiaceae, for example, the deadwood (Lamium purpureum L.); Legumes, for example alfalfa lupulin (Medicago lupulina L.);

Malvaceae, for example the mallow with small flowers (Malva parviflora L.), the mallow (Malva silvestris L.);

Papaveraceae eg poppy (Papaver rhoeas L.);

Polygonaceae, for example, knotweed (Polygonum aviculare L.), lady's thumb (Polygonum persicaria L.);

Rubiaceae, for example cleavers (Galium aparine L.);

Gramineae, for example, ryegrass (Lollium spp.), Foxtail (Setaria verticillata (L.) P. Beauv.), Crabgrass (Digitaria sanguinalis (L.) Scop), barnyard grass [Echinochloa crus galli (L.) P.) ·

The mixture according to the present invention is particularly useful in the control of the following weeds: the Barcelona fleabane (Conyza albida Sprengel), the Buenos Aires fleabane (Conyza bonariensis (L.) Cronq) and the ryegrass (Lollium spp.) .

It is an object of the present invention to provide a novel synergistic herbicidal mixture which comprises the active substances iodosulfuron-methyl (I) or salts thereof and flazasulfurone (II).

In a preferred embodiment of the invention, the weight ratio of flazasulfurone to iodosulfurone in the mixture is in the range of 2: 1 to 7: 1.

In a more preferred embodiment of the invention, the weight ratio of flazasulfurone to iodosulfurone in the mixture is in the range of 3: 1 to 4: 1.

In an even more preferred embodiment of the invention, the weight ratio of flazasulfurone to iodosulfurone in the mixture is 4: 1.

The mixture according to the present invention can be obtained by tank mixing, immediately before application, of commercially available formulations of the two active substances, or, alternatively, a formulation can be used, which comprises both active substances. and the usual adjuvants, in the form of water-dispersible granules (hereafter referred to herein as the official international designation: WG formulation) or in the form of a suspension of particles in the oil (henceforth designated in this application by the official international designation: OD formulation).

The WG formulations are prepared according to methods known to those skilled in the art, they can be obtained for example by an extrusion process comprising the steps of: - mixing active substances (I) or (la) and (II) and subsequently grinding the mixture in an air jet mill until a sufficiently fine particle size is obtained (about 95% of the particles are less than 10 μm); add the previous mixture to the remaining components of the formulation (dispersing agents, wetting agents, antifoaming agents, disintegrating agents, stabilizing agents, pH regulators and inert agents), and mix in a suitable mixer (eg Nautamix mixer) ); adding water to the previous mixture to form a homogeneous "paste", which is subsequently fed to an extruder (for example of the "basket" type), into which the material is pushed through a perforated cloth (0, 8 mm to 1 mm in diameter) due to the action of the extrusion blades; injecting the wet granules from the extruder into a spheronizer, wherein a rotating plate promotes the collision of the granules against the walls of the equipment and against other granules, resulting in their plastic deformation, giving rise to the formation of spheres; and drying the resulting product with a hot air stream in a fluid bed dryer.

OD formulations are prepared according to the present invention by methods known to those skilled in the art, they can be obtained for example by a wet grinding process comprising the steps of: adding stirring, to a vegetable or mineral oil a set of additives (dispersing agents, wetting agents, stabilizing agents, pH regulators); add to the solution obtained in the previous step the active substances (I) or (Ia) and (II) until a dispersion in the homogeneous oil; atomizing the dispersion in the oil resulting from the previous step by means of a spherical chopper cooled to obtain a particle size distribution where .95 95-8 μm; and adding to the anterior suspension a structuring agent and continue to stir until a dispersion in the homogeneous oil.

According to a preferred embodiment, the formulation containing the active substances according to the present invention is in the form of an OD formulation.

It is another object of the present invention to provide a method for controlling weeds in olive and grapevine crops which comprises applying, at the beginning of post-emergence, the mixture according to the present invention diluted in an amount of sufficient water (normally 150 to 600 liters per hectare for tractor spreading) to ensure a uniform application on the soil and weeds of 25 g to 35 g of flazasulfurone and 5 g to 12.5 g of iodosulfurone per hectare .

In a preferred embodiment, the treatment method comprises the application of 30 g of lazasulfurone and 7.5 g to 10 g of iodosulfurone per hectare.

In a more preferred mode, the treatment method comprises the application of 30 g of flazasulfurone and 7.5 g of iodosulfurone per hectare.

Biological effectiveness

The mixture comprising iodosulfuron-methyl-sodium and flazasulfurone was applied early postemergence to the olive culture, using a dosage of 30 g / ha flazasulfurone and 7.5 g / ha iodosulfurone. (in the form of iodosulfurone-methyl-sodium).

The following were also applied in parallel: a formulation containing flazasulfurone in which the dosage applied was 50 g / ha; a formulation containing iodosulfurone and diflufenican, in which the dosage applied was 10 g / ha of iodosulfurone (in the form of iodosulfurone-methyl-sodium) and 150 g / ha of diflufenican.

The tests were carried out in Portugal and were carried out in accordance with the good experimental practices defined by Regulation CE 1107/2009.

The tests were performed by block randomization, 4 times, a side-by-side slice with each treated area remaining untreated.

An evaluation of the effectiveness was carried out 28 days after the application of the mixture according to the present invention, which obtained the following results:

Table 1: Efficiency results

It can be seen that the value of the efficiency obtained for the mixture is much greater than that of any of the active substances applied in isolation, even when the dosages of active substances applied in isolation are significantly higher than the dosages in the mixture.

In order to quantify the synergistic effect resulting from the combination of active substances, the methodology described by Colby (Colby, S.R., "Calculating synergistic and antagonistic response of

herbicide compositions, "Weeds 15, pp. 20-22, 1967), according to which the expected efficiency (EE) for the determined mixture of active ingredients is compared with an experimentally observed efficiency (E) using the Colby formula: EE = x + y - (xy) / 100 Where: EE is the expected efficiency expressed in%, using the mixture of active compounds A and B in concentrations a and b; x is an efficacy expressed in%, using the active compound A in the concentration a; y is an efficacy expressed in% using the active compound B in the concentration b.

If the observed efficiency (E) exceeds the calculated efficiency (EE), there is a synergistic effect.

Although the results shown in Table 1 do not allow the use of the Colby formula with all the rigor that is required, since the dosages of the active substances used individually are not identical to the dosages in the mixture and because Since iodosulfurone has not been tested in isolation but has been mixed with diflufenican, we can use the Colby formula to obtain an estimate of the expected efficiency for the mixture according to the present invention.

This estimate will correspond to an approximation by excess of the theoretical value, since the determination of extreme flazasulfurone is greater than that of flazasulfurone in the binary mixture and since, because of the use of a mixture of iodosulfurone and diflufenican in place and in place of extreme iodosulfurone, not only is the dosage of iodosulfurone greater than the dosage in the mixture, but we also consider that the efficacy of diflufenican is zero.

If we add the values in Table 1 to Colby's formula, we obtain a value expected for an efficiency of 57.6% lower than the value observed experimentally (58.9%).

The calculations having been made as a very unfavorable case for a mixture according to the present invention, it is clear that a synergistic effect resulting surprisingly from the mixture of the two active substances is appropriate.

Claims (7)

A synergistic herbicidal mixture, characterized in that it comprises iodosulfuron-methyl or its salts and flazasulfurone. The blend of claim 1, characterized by a weight ratio of flazasulfurone to iodosulfuron-methyl in the mixture in the range of 2: 1 to 7: 1. 3. The blend of claim 2, characterized by a weight ratio of flazasulfurone to iodosulfuron-methyl in the mixture in the range of 3: 1 to 4: 1. Mixture according to claim 3, characterized by a weight ratio of flazasulfurone to iodosulfuron-methyl in the 4: 1 mixture. 5. A method for controlling weeds in olive and vine crops, characterized in that it comprises a step of applying, at the beginning of post-emergence, 25 to 35 g of flazasulfurone and 5 to 12.5 g iodosulfurone per hectare. 6. Process according to claim 5, characterized in that 30 g of flazasulfurone and 7.5 to 10 g of iodosulfurone are applied per hectare. 7. Process according to claim 6, characterized in that 30 g of flazasulfurone and 7.5 g of iodosulfurone are applied per hectare.