SK284515B6 - Synergistic fungicidal composition based on bromuconazole and triazole compound and method of treatment intended to control or prevent fungal attacks on crops - Google Patents

Abstract

Described is fungicidal composition comprising bromuconazole (B) and another triazole (A) chosen from tebuconazole and epoxiconazole.

Description

The invention relates to a fungicidal composition suitable for the treatment of crop plants against fungal attack based on bromuconazole and another triazole compound and a method of treating crop plants against fungal attack.

BACKGROUND OF THE INVENTION

The effectiveness of bromuconazole in combating steblolam (cereal hatching) of cereals is known. This disease caused by the fungus Pseudocercosporella herpotrichoides causes considerable damage, especially in winter cereals. However, the efficacy of bromuconazole in the fight against some other cereal diseases, in particular brown rust (a disease caused by Puccinia recondiía) and septoriosis (a disease caused by Septoria iritici), is insufficient, especially when the application of the active substance takes place at a stage called "Last foliar treatment". This term refers to the agrochemical treatment at the time when the cereals have reached the developmental stage corresponding to the development of the last leaf of the stem. In particular, the persistence of bromuconazole must be improved in this respect. Persistence is understood to mean the time during which the agrochemical product is able to realize its effect from the moment of its application.

From the Pesticide Manual 10th edition, Clive Tomlin (published by the British Crop Protection Council and the Royal Soceity of Chemistry), the efficacy of certain triazoles, such as tebuconazole, in combating rust and cereal septoriosis is also known.

However, there is still a need to improve the efficacy, in particular to reduce the application rates of tebuconazole needed to control the disease, and also to expand the range of agrochemical products available to farmers who, with such an expanded offer, will be able to find the best solutions for each specific issue.

It is therefore an object of the present invention to provide a novel fungicidal composition suitable for achieving said intended goal.

Another object of the invention is to propose a novel fungicidal composition comprising bromuconazole suitable for the treatment of brown rust and / or cereal septoriosis and / or ear diseases (fusariosis), in particular cereals.

It is a further object of the invention to provide a novel fungicidal composition comprising bromuconazole which has improved persistence.

It has now been found that these objectives can be achieved in whole or in part by the fungicidal composition of the invention.

SUMMARY OF THE INVENTION

The fungicidal composition of the present invention is characterized in that it comprises bromuconazole (B) and another triazole (A) selected from tebuconazole and epoxiconazole.

The specified bromuconazole (B) and triazole (A) products are well known to those skilled in the art and described in "The Pesticide Manual", 10th edition by Clive Tomlin, published by the British Crop Protection Council.

The weight ratio of B / A substances in the composition of the invention is generally 0.1 to 20 and preferably 0.5 to 10. The composition of the invention is advantageous for its spectrum of action and for low application rates which may be used, wherein: the latter characteristic is particularly important for well-understood environmental reasons. Remarkable synergistic effects can thus be observed in the composition of the invention. These synergistic effects are mainly demonstrated by the Tammes method described in "Isoboles, a graphical representation of synergism in pesticides", Netherlands Journal of Plant Patology, 70 (1964), pp. 73-80.

In a preferred embodiment of the invention, tebuconazole is included in the composition of the invention as triazole A. In this case, the weight ratio B / A is preferably 0.5 to 5 and in particular 1 to 3.

The fungicidal composition of the invention typically comprises 0.05 to 95% of a mixture of bromuconazole and triazole A.

It may be a concentrated composition, i. j. o a commercial product consisting of both active substances. It may also be a diluted composition that is ready to be sprayed over the culture being treated. In the latter case, the composition may be diluted with water, either by diluting a commercial concentrated composition containing both active ingredients (the mixture obtained is called a ready mix) or by diluting the two separate compositions, each containing one of the active ingredients, immediately prior to use of the fungicidal composition, the mixture obtained being referred to as a tank mix.

The composition according to the invention may furthermore comprise all customary additives and auxiliaries of the phytosanitary compositions, in particular carriers, surface-active agents, adhesives and flow-promoting agents of the composition over the crop surface to be treated.

As used herein, the term carrier refers to a natural or synthetic, organic or mineral substance which is added to the active ingredients for ease of application to the plant. Thus, the carrier is generally inert and must be agriculturally acceptable and particularly acceptable for the plant to be treated. The carrier may be solid (clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers, etc.) or liquid (water, alcohols, ketones, petroleum fractions, aromatic or paraffinic hydrocarbons, chlorinated hydrocarbons, liquefied gases, etc.).

The surfactant may be an emulsifying, dispersing or wetting agent of the ionic or nonionic type. For example, polyacrylic acid salts, lignosulfonic acid salts, phenolsulfonic or naphthalenesulfonic acid salts, polycondensates of ethylene oxide with fatty alcohols, fatty acids or fatty amines, substituted phenols (especially alkylphenols or arylphenols), sulfosuccinic acid esters (especially taururin derivatives) may be mentioned. , phosphoric acid esters and alcohols or polyoxyethylene phenols. For a satisfactory dispersion of the active ingredients in water and their good applicability to plants, it is desirable that the fungicidal composition comprises at least one surfactant.

The compositions of the invention may also contain any kind of other ingredients, such as protective colloids, adhesives, thickeners, thixotropic agents, penetrating agents, stabilizing agents, sequestering agents, pigments, dyes and polymers.

Generally defined, the composition of the invention may contain all solid or liquid additives which correspond to conventional phytosanitary product formulation techniques.

SK 284515 Β6

The compositions of the invention may be in solid, gel, or liquid form, in the latter case the composition of the invention may be in the form of a solution, suspension, emulsion or emulsifiable concentrate. Liquid compositions are preferred because of their ease of applicability and their ease of preparation.

Powder formulations (dusts) or dispersions (having an active ingredient content which may be up to 100%), wettable powders and granules for dry application as well as dispersible or soluble granules may be mentioned as solid composition forms.

Wettable powders (or spray powders) as well as dispersible granules usually contain 20 to 95% of the active ingredients and, in addition to the carrier, 0 to 5% of the wetting agent, 3 to 10% of the dispersing agent and 0 to 10% of one or more stabilizing agents. and / or other additives such as pigments, dyes, penetrating agents, adhesives, anti-caking agents, etc. Of course, some of these compositions, such as wettable powders or dispersible granules, are intended to form liquid compositions immediately prior to application of the fungicidal composition.

Liquid forms of the compositions according to the invention include solutions, in particular water-soluble concentrates, emulsifiable concentrates, emulsions, suspension concentrates, aerosols and pastes.

Emulsifiable or soluble concentrates usually contain 10 to 80% of active ingredients, while ready-to-use emulsions or solutions contain 0.01 to 20% of active ingredients. The emulsifiable concentrates may contain, in addition to the solvent, 2 to 20% of appropriate additives, if desired, such as stabilizing agents, surfactants, penetrating agents, corrosion inhibitors, colorants or the said adhesives. Emulsions of any desired concentration, which are particularly suitable for application to the aerial parts of the plants to be treated, can be obtained from these concentrates by dilution with water. As already mentioned, aqueous dispersions and emulsions, for example compositions obtained by diluting a wettable powder or an emulsifiable concentrate with water, are within the scope of the invention. The emulsions may be water-in-oil or oil-in-water emulsions, and the emulsions may have a thick consistency, for example a mayonnaise consistency.

Suspension concentrates, which are also sprayable, are stable liquid products that do not show thickening or sedimentation upon storage, which concentrates usually contain 10 to 75% of active ingredients, 0.5 to 15% of surfactants, 0.1 up to 10% of thixotropic agents, 0 to 10% of appropriate additives such as pigments, dyes, antifoams, corrosion inhibitors, stabilizers, penetration agents and adhesives and contain as carrier a water or an organic liquid in which the active ingredients are poorly soluble or insoluble. Certain solid organic substances or mineral salts may be dissolved in the liquid carrier to prevent sedimentation or to prevent the freezing of water.

The compositions of the invention are prepared by known methods.

Thus, for the preparation of sprayable powders or wettable powders, a perfect mixture of active ingredients and excipients is prepared by mixing in suitable mixers, and then this mixture is ground in suitable gases or crushers. In this way spray powders are obtained, their wettability and suspendability being very good. They may be suspended in water to obtain a suspension of any desired concentration, such suspensions being particularly advantageous for application to the aerial parts of plants.

Pastes or suspension concentrates may be prepared instead of wettable powders. The conditions and methods of preparing and using these pastes are similar to the conditions and methods of preparing and using wettable powders or sprayable powders, the necessary part of the milling operation being simply carried out in a liquid medium.

Dispersible granules are usually prepared by agglomeration, extrusion or compression in a suitable granulation system of wettable powder compositions. Granules for dry application are usually obtained by impregnating the granular carrier with a solution or emulsion of the active ingredients.

The invention also relates to a method of curative treatment of crop plants for the treatment or prevention of fungal infestation of said crops, which comprises applying an effective and non-phytotoxic dose of the composition according to the invention to the aerial parts of the crop plants.

Said composition is preferably used in such a way that the applied dose of bromuconazole is between 100 and 300 g / ha, preferably between 150 and 250 g / ha, while the dose of triazole A is between 50 and 250 g / ha, preferably between 75 and 250 g / ha. 200 g / ha.

This dose depends on the nature of the disease, the stage of development of the treated plant, the degree of infestation and the climatic conditions.

In a preferred embodiment, the fungicidal composition of the invention is compound A tebuconazole, wherein the dose of tebuconazole is between 75 and 250 g / ha, preferably between 100 and 150 g / ha.

Fungal diseases are essentially diseases such as septoriosis (Septoria tritici, Septoria nodorum), rust (Puccinia striiformis, Puccinia reconditd) and ear fusarioses (Fusarium culmorum, Microdochium nivalé).

Crop crops suitable for application of the curative treatment method of the invention include cereals, especially barley, wheat, rye and preferably wheat.

In the following, the invention will be explained in more detail by means of specific examples thereof, the examples being illustrative only and not in any way limiting the scope of the invention, which is clearly defined by the definition of the claims.

In the accompanying drawings, the dose of each active ingredient used alone to achieve the indicated control of a phytopathogenic fungus is compared to the dose of the two active ingredients used in the composition. The effective dose of each active ingredient used alone is indicated on the abscissa and advisory axes, with a line intersecting the two axes connecting the two doses. For the two active substances used in the mixture, the dose of the mixture at a given ratio is indicated by a point.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Greenhouse test using a fungicidal composition comprising a mixture of bromuconazole and tebuconazole for controlling Puccinia recondita causing brown rust of wheat.

Either a composition comprising bromuconazole in the form of a concentrated suspension containing the said active ingredient of 200 g / l, or a composition comprising tebuconazole in the form of an emulsifiable concentrate containing the active ingredient of 250 g / l or the composition according to the invention obtained by mixing the two previous compositions.

For the active ingredients in the mixture, the weight ratio of bromuconazole / tebuconazole is 1,1,5,2,2,5 and 3.

Wheat plants (variety Talent) are grown in pots. When these plants reach the age of 14 days corresponding to the Zadocks 11 stage, they are sprayed with each of the above compositions.

The Zadocks scale is defined in an article published in Phytiatry of Phytopharmacy 1977, 26, pp. 129-140, entitled "Un code décimal pour les stades de cerées des cerées" by JC Zadocks, TT Chang and CF Konzak.

Twenty-four hours after this treatment, each plant is infested by spraying an aqueous spore suspension (100,000 spores / cm ³ ) of Puccinia recondiia.

After this infestation, the wheat plants are incubated at 20 ° C and 100% relative humidity for 24 hours, then transferred to a greenhouse operated at 18 ° C and 70% relative humidity.

Twelve days after infestation, the percent infestation of the foliate surface is evaluated. The percentage destruction of the phytopathogenic fungus is calculated by comparison with a control wheat plant that has not been treated with the active ingredient and which has been infested with Puccinia recondita.

The results obtained are plotted as 80% destruction of the parasitic fungus in a Tammes plot showing the tebuconazole doses in g / ha on the abscissa and the bromuconazole doses in g / ha on the abscissa.

The graph shown in FIG. 1, which shows that the addition of a dose of tebuconazole of less than 28 g / ha (corresponding to the dose of tebuconazole alone to be administered to achieve 80% parasitic fungal destruction) makes it possible to reduce the dose of bromuconazole needed to 80% parasitic fungal destruction well below 337 g / ha (this value corresponds to the dose of bromuconazole alone to be administered to achieve the same 80% destruction of said parasitic fungus).

The arrangement of the points obtained in the above graph thus demonstrates a bilateral effect which is classified as 'two sided effect' in the English language under the Tammes method.

This arrangement corresponds to a type III isobol according to the above method (page 75 of the corresponding bibliographic reference already cited) and is a hallmark of synergy.

Example 2

A greenhouse test using a fungicidal composition comprising a mixture of bromuconazole and epoxiconazole in controlling the Septoria tritici fungus causing wheat septoriosis.

Either a composition comprising bromuconazole in the form of a concentrated suspension with an active ingredient content of 200 g / l, or a composition comprising epoxiconazole in the form of a concentrated suspension containing an active ingredient of 125 g / l, or still a composition according to the invention obtained by mixing both.

For the active ingredients in the mixture, the weight ratio of bromuconazole / epoxiconazole is 1, 3, 4, 5 and 6.

Wheat plants (Darius variety) are grown in pots. When these plants reach the age of 14 days corresponding to the Zadocks 11 stage, they are sprayed with each of the above compositions.

Twenty-four hours after this treatment, each plant is infested by spraying an aqueous spore suspension (250,000 spores / cm ³ ) of Septoria tritici.

After this infestation, the wheat plants are incubated at 18 ° C and 100% relative humidity for 4 days, then transferred to a greenhouse operated at 18 ° C and 90% relative humidity.

Twenty days after the infestation, the percent infestation of the foliate surface is evaluated. The percentage destruction of the phytopathogenic fungus is calculated by comparison with a control wheat plant that has not been treated with the active ingredient and which has been infested with Septoria tritici.

The results obtained are plotted as 50% destruction of the parasitic fungus in a Tammes plot showing the epoxiconazole doses in g / ha on the abscissa and the bromuconazole doses in g / ha on the abscissa.

The graph shown in FIG. 2, which shows that the addition of a dose of epoxiconazole of less than 7 g / ha (corresponding to the dose of epoxiconazole alone required to achieve 50% destruction of the parasitic fungus) makes it possible to reduce the dose of bromuconazole needed to achieve 50% destruction of the parasitic fungus well below 101 g / ha (this value corresponds to the dose of bromuconazole alone to be administered to achieve 50% destruction of said parasitic fungus). The arrangement of the points obtained in the above graph, in particular those corresponding to ratios 3, 4, 5 and 6, thus demonstrates a bilateral effect which is a hallmark of synergy.

PATENT CLAIMS

Claims (9)

A synergistic fungicidal composition comprising bromuconazole (B) and another triazole (A) selected from tebuconazole and epoxiconazole in a B / A weight ratio of between 0.1 and 20. A synergistic fungicidal composition according to claim 1, characterized in that it comprises bromuconazole (B) and another triazole (A) selected from tebuconazole and epoxiconazole in a weight ratio B / A between 0.5 and 10. Synergistic fungicidal composition according to claim 1 or 2, characterized in that it contains tebuconazole as triazole A, the B / A weight ratio being between 0.5 and 5, preferably between 1 and 3. A synergistic fungicidal composition according to any one of claims 1 to 3, characterized in that it comprises 0.05 to 95% by weight of a mixture of bromuconazole and triazole A. A method of curative or preventive treatment of crop plants against fungal attack, characterized in that an effective and non-phytotoxic dose of the synergistic composition according to any one of claims 1 to 4 is applied to the above-ground part of the crop plants. Method according to claim 5, characterized in that a dose of the composition corresponding to an applied dose of bromuconazole of between 100 and 300 g / ha, preferably of between 150 and 250 g / ha, and an applied dose of triazole A of between 50 and 250 g / ha are applied. preferably between 75 and 200 g / ha. Method according to claim 5 or 6, characterized in that tebuconazole is used as triazole A, wherein a dose of a composition comprising a mixture of triazole A and bromuconazole corresponding to an application rate of tebuconazole of between 75 and 250 g / ha, preferably between 100 and 150 g / ha. Method according to one of claims 5 to 7, characterized in that the fungal attack comprises septoriosis, in particular Septoria tritici and Septoria nodorum, rust, in particular Puccinia striiformis and Puccinia recondita and ear fusarioses, in particular Fusarium culmorum and Microdochium nivale. Method according to one of claims 5 to 8, characterized in that the crop plants are cereals, in particular barley, wheat, rye, triticale, preferably wheat.