FR2732190A1 - FUNGICIDAL COMPOSITION BASED ON PROCHLORAZE AND A TRIAZOLE COMPOUND - Google Patents

Abstract

Fungicidal composition comprising bromuconazole and prochloraz and method for treating crops using this composition.

Description

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  The present invention relates to a fungicidal composition useful for the treatment of fungal attacks of cultures, based on prochloraze and bromuconazole. It also relates to a process for treating crops

having the same purpose.

  We know the effectiveness of prochloraze in the fight against foot

  pour cereal. This disease, caused by the fungus Pseudocercosporella herpotrichoides, is the cause of significant damage mainly on winter cereals. For several years now, prochloraz has experienced shortcomings in its effectiveness and regularity of action, due to the appearance of

  strains with some resistance.

  We also know the effectiveness of prochloraze in the fight against Fusarium wilt of wheat ears, this disease being caused mainly by the 2 phytopathogenic fungi called Fusarium roseum and Microdochium nivale. However, it is always desirable to improve this efficiency, in particular by reducing the dose of prochloraze necessary for the control of this disease or even by widening the possibilities of choice offered to the farmer,

  so that he finds the best solution for his particular problem.

  An object of the invention is therefore to provide a new composition

  fungicide, useful for the problem outlined above.

  Another object of the invention is to propose a new fungicidal composition useful in the treatment of wheat foot rot and fusarium head blight

of wheat.

  It has now been found that these goals can be fully achieved

  or in part thanks to the fungicidal composition according to the present invention.

  The fungicidal composition according to the invention is characterized in that it

  includes prochloraze and bromuconazole.

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  Prochloraze and bromuconazole are two active ingredients well known to those skilled in the art and which are described in the book: "The Pesticide Manual" 10th edition, by Clive Tomlin, published by the British Crop Protection Council. The use of bromuconazole is also known in the fight against cereal diseases such as foot rot and Fusarium head blight. The bromuconazole / prochloraze weight ratio, in the composition according to the invention, is generally between 0.25 and 4, preferably between 0.25 and 0.75. Bromuconazole is also known for its use against foot rot. The composition according to the invention is advantageous by the spectrum of activity and the low doses which can be used for the active ingredients, the latter quality being particularly important for easily understandable ecological reasons. Thus, the composition according to the invention makes it possible to observe remarkable synergistic effects. These synergistic effects are notably attested by the application of the method of Tammes, "Isoboles, a graphic representation of synergism in pesticides" Netherlands Journal of Plant Pathology, 70 (1964),

p. 73-80.

  The fungicidal composition according to the invention usually contains

  0.5 to 95% mixture of prochloraze and bromuconazole.

  U may be the concentrated composition, that is to say the commercial product combining the two active materials. It can also be the diluted composition ready to be sprayed onto the culture to be treated. In the latter case, dilution with water can be carried out either from a concentrated commercial composition containing the two active materials (this mixture is called "ready to use" or "ready mix", in English) , or by means of the extemporaneous mixture (called in English "tank mix") of two

  concentrated commercial compositions each containing an active ingredient.

  The composition according to the invention can also comprise all the usual additives or adjuvants for phytosanitary compositions, in particular

  supports, surfactants, adhesion agents and fluence agents.

  By the term "support", in the present description, is meant an organic or mineral, natural or synthetic material, with which the active materials are associated to facilitate their application to the plant. This support is therefore generally inert and it must be acceptable in agriculture, in particular on the treated plant. The support can be solid (clays, natural silicates or

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  synthetic, silica, resins, waxes, solid fertilizers, etc.) or liquid (water, alcohols, ketones, petroleum fractions, aromatic or paraffinic hydrocarbons,

  chlorinated hydrocarbons, liquefied gases, etc.).

  The surfactant can be an emulsifying, dispersing or wetting agent of ionic or nonionic type. Mention may be made, for example, of salts of polyacrylic acids, salts of lignosulfonic acids, salts of phenolsulfonic or naphthalene sulfonic acids, polycondensates of ethylene oxide on fatty alcohols or on fatty acids or on fatty amines , substituted phenols (especially alkylphenols or arylphenols), ester salts of sulfosuccinic acids, taurine derivatives (especially

  alkyltaurates), phosphoric esters of polyoxyethylated alcohols or phenols.

  The presence of at least one surfactant is desirable to promote the dispersion of the active materials in water and their good application on plants. This composition can also contain all kinds of other ingredients such as, for example, protective colloids, adhesives, thickeners, thixotropic agents, penetrating agents, stabilizers, sequestrants,

  pigments, dyes, polymers.

  More generally, the composition according to the invention can include all the solid or liquid additives corresponding to the usual techniques of

  formulation of phytosanitary products.

  The composition according to the invention can be in solid, gelled, or liquid form, and in the latter case in the form of solutions or suspensions or emulsions or emulsifiable concentrates. Liquid compositions are preferred, both because of their ease of use and because of their

simplicity of manufacture.

  As forms of solid compositions, mention may be made of powders for dusting or dispersion (with active compound content of up to 100%), wettable powders and granules for dry spreading as well as granules

dispersible or soluble.

  Wettable powders (or spraying powders) as well as dispersible granules usually contain 20 to 95% of active ingredients, and in addition to the solid support, 0 to 5% of a wetting agent, 3 to 10% of a dispersing agent, and, when necessary, from 0 to 10% of one or more stabilizers and / or other additives, such as pigments, dyes,

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  penetration, adhesives, or anti-clumping agents, dyes, etc. It is understood that some of these compositions, such as wettable powders or dispersible granules, are intended to constitute liquid compositions during application. As forms of liquid compositions, mention may be made of solutions, in particular water-soluble concentrates, emulsifiable concentrates,

  emulsions, concentrated suspensions, aerosols, pastes.

  The emulsifiable or soluble concentrates most often comprise 80% of active materials, the emulsions or solutions ready for application containing, for their part, 0.01 to 20% of active materials. In addition to the solvent, the emulsifiable concentrates can contain, when necessary, 2 to 20% of suitable additives such as stabilizers, surfactants, penetration agents, corrosion inhibitors, dyes or adhesives previously cited. From these concentrates, emulsions of any desired concentration, which are suitable, can be obtained by dilution with water.

  particularly when applied to the aerial parts of the plant to be treated.

  As has already been said, the aqueous dispersions and emulsions, for example the compositions obtained by diluting with water a wettable powder or an emulsifiable concentrate according to the invention, are included in the general scope of the present invention. The emulsions can be of the water-in-oil or oil-in-water type and they can have a thick consistency like that of a "mayonnaise". Concentrated suspensions, also applicable in spraying, are a stable fluid product, not giving rise to thickening or the formation of a sediment after storage, and they usually contain from 10 to 75% of active ingredients, from 0.5 15% of surfactants, 0.1 to 10% of thixotropic agents, 0 to 10% of suitable additives, such as pigments, dyes, anti-foaming agents, corrosion inhibitors, stabilizers, penetrating agents and adhesives and, as a support, water or an organic liquid in which the active ingredients are sparingly or not soluble: certain organic solids or mineral salts can be dissolved in the

  support to help prevent sedimentation or as antifreeze for water.

  The composition according to the invention is prepared according to known methods

in itself.

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  Thus, to obtain the spraying powders or wettable powders, the active materials are intimately mixed in appropriate mixers with the additional substances and are ground with mills or other grinders. This gives sprayable powders whose wettability and suspension are advantageous; they can be suspended with water at any desired concentration and these suspensions can be used very advantageously in particular for application to the aerial parts of plants. Instead of wettable powders, concentrated pastes or suspensions can be produced. The conditions and methods of making and using these pastes are similar to those of wettable powders or spraying powders, part of the necessary grinding operation being simply

performed in liquid medium.

  The dispersible granules are usually prepared by agglomeration or extrusion or compacting, in suitable granulation systems, of compositions of the wettable powder type. Granules for dry spreading are usually obtained by impregnating a granulated support with a solution

  or an emulsion of the active ingredients.

  Finally, the invention relates to a treatment method intended to combat or prevent fungal attacks on crops, characterized in that an effective and non-effective dose is applied to the aerial parts of the plants.

  phytotoxic of a composition according to the invention.

  This composition is advantageously used so that the applied dose of prochloraze is between 250 and 500 g / ha, preferably between 300 and 450 g / ha and the dose of bromuconazole is between 180 and 280 g / ha, preferably between 200 and 250 g / ha. This dose depends on the nature of the disease, the stage of development of the treated plant, the degree

  infestation, and climatic conditions.

  Fungal attacks are those caused by foot rot (Pseudocercosporella herpotrichoides), Fusarium head blight (Fusarium roseum and Microdochium nivale), Septoria leaf spot (Septoria tritici, Septoria nodorum), rust (Puccinia striiformis, Puccinia recondita), and oidiums (Erisyphe graminis).

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  The crops suitable for the treatment process according to the invention are cereals, in particular barley, wheat, rye, triticale,

preferably wheat.

  The following examples are given purely by way of illustration and not

  limiting the advantageous properties of the compositions according to the invention.

  EIxempe 1 ,: In vitro test of a composition comprising a mixture of bromuconazole and prochloraze on Pseudocercosporella herpotrichoides responsible for the wheat spiderwort: A nutritive medium consisting of maize flour and agar is introduced

  by supercooling in a series of Petri dishes (20 ml per dish).

  During the filling of the boxes, 200 μl of a solution of the active ingredients to be tested (alone or in mixture) are injected into acetone, so as to

  obtain the desired final concentration.

  In the case of active ingredients in mixture, the weight ratio

  bromuconazole / prochloraze is 0.25; 0.33; 0.5; 1; 2; 3; 4.

  We take as a witness petri dishes similar to the preceding ones, into which are poured similar amounts of a nutritive medium which

containing no active ingredient.

  After 24 hours, a 5 mm diameter pellet, comprising a fragment of mycelium, taken from a mother culture of Pseudocercosporella herpotrichoides, is placed in the center of each box. Petri dishes are

  stored at 20 ° C for 3 weeks.

  The growth of the fungus (measured by the diameter of the mycelial growth) in the boxes containing the active ingredient or the mixture of active ingredients to be tested is then compared to that of the same

  fungus in the box used as a control.

  The results obtained are reported in the form of points, corresponding to the inhibition of 50% of the mycelial growth of the parasite and placed in a diagram of Tammes which contains on the abscissa the doses of prochloraze

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  expressed in mg / l and on the ordinate the doses of bromuconazole also in mg / l. The diagram of FIG. 1 is obtained in which it appears that the addition of a dose of bromuconazole of less than 0.15 mg / 1 (which corresponds to the dose of bromuconazole alone which it is necessary to apply in order to obtain the destruction of 50% of the parasite) allows, in a perfectly unexpected way, to lower the dose of prochloze necessary for the destruction of 50% of the parasite below 0.05 mg / l (this value corresponding to the dose of prochloraze alone that 'it is necessary to apply to obtain this same percentage of

destruction).

  The arrangement of the points obtained therefore indicates a bilateral effect, qualified in the English language according to the Tammes method cited above of "two sided effect". This arrangement corresponds to an In type isobole according to said method (page 75 of the corresponding bibliographic reference already

  cited) and is characteristic of a synergy.

  EXAMPLE 2 In Vitro Test of a Composition Comprising a Mixture of Bromuconazole and Prochloraze on Microdochium Nivale, Responsible for Fusarium Wilt of the Ear of Wheat: A nutritive medium consisting of corn flour and agar is introduced

  by supercooling in a series of Petri dishes (20 ml per dish).

  During the filling of the boxes, 200 l of a solution of the active ingredients to be tested (alone or as a mixture) are injected into acetone, so as to

  obtain the desired final concentration.

  In the case of active ingredients in mixture, the weight ratio

  bromuconazole / prochloraze is 0.33; 0.5; 1; 2; 3.

  We take as a witness petri dishes similar to the preceding ones, into which are poured similar amounts of a nutritive medium which

containing no active ingredient.

  After 24 hours, a 5 mm diameter pellet, comprising a fragment of mycelium, taken from a mother culture of Microdochium nivale, is placed in the center of each box. Petri dishes are kept at 20

 C for 7 days.

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  We proceed to the observation of the results and the construction of the

  Tammes diagram by proceeding as in Example 1.

  FIG. 2 is thus obtained which is characteristic of a bilateral effect similar to that observed in FIG. 1 of Example 1 and is therefore also characteristic of a synergy.

Claims (8)

  1. Fungicidal composition characterized in that it comprises prochloraze and bromuconazole. 2. fungicidal composition according to claim 1, characterized in that the bromuconazole / prochloraze weight ratio is between 0.25 and 4, preferably between 0.25 and 0.75.   3. fungicidal composition according to one of claims 1 or 2,   characterized in that it contains from 0.5 to 95% mixture of prochloraze and bromuconazole.   4. Treatment process intended to combat or prevent fungal attacks on crops, characterized in that an effective and non-phytotoxic dose of a composition is applied to the aerial parts of the plants   according to one of claims 1 to 3.   5. Method according to claim 4, characterized in that the composition dose is such that the applied dose of prochloraze is between 250 and 500 g / ha, preferably between 300 and 450 g / ha and the applied dose of bromuconazole is between 180 and 280 g / ha, preferably between 200 and 250 g / ha.   6. Method according to one of claims 4 or 5, characterized in that   fungal attacks are those caused by foot rot, fusarium wilt   ear, septoria, rust, and powdery mildew.   7. Method according to one of claims 4 to 6, characterized in that   the crops targeted are cereals, notably barley, wheat, rye, triticale.   8. Method according to one of claims 4 to 7, characterized in that the target crop is wheat.