FR2732191A1 - Fungicide for banana plants comprises application of phosphite cpd. - Google Patents

Abstract

Treatment for cercosporiosis of bananas comprises application of a cpd. A to the aerial parts of the plants. A = mono-, di- or tri-valent cation salts of a mono-alkyl phosphite, e.g. Fosetyl-Al (aluminium tris-O-ethyl phosphonate), or phosphorous acid and its alkali and alkaline-earth salts.

Description

 Antifungal treatment method for banana plants

 The present invention relates to a method for the treatment of Sigatoka leaf spot, and a fungicidal composition having the same purpose.

Sigatoka leaf spot caused by fungi
Mycosphaerella rruzsicola and / or Mycosphaerellafijiensis causes the appearance of yellow and / or brown necrosis on the leaves, followed by a reduction in the number of leaves of the plants. This results in significant losses in the yield of fruit from the contaminated plantations.

 For their effectiveness against Sigatoka disease susceptible to reach banana products such as mancozeb or chlorotalonil are known.

 However, it is always desirable to extend the choices available to the farmer, so that the farmer finds the best solution for his particular problem.

 Also known for their effectiveness against Sigatoka disease reaching or likely to reach bananas, compounds triazole type.

 However, the effectiveness of these compounds is no longer always satisfactory, particularly because of the appearance of strains of fungi resistant to triazoles.

 An object of the invention is therefore to provide a novel method of preventive and / or curative treatment of Sigatoka leaf spot.

 Another object of the invention is to provide a novel fungicidal composition useful in the preventive or curative treatment of Sigatoka leaf spot.

 Another object of the invention is to propose a novel triazole-based composition which does not give rise to triazole resistance problems.

 It has now been found that these aims can be achieved in whole or in part by the treatment method according to the present invention, as well as the fungicidal composition also object of the invention.

The subject of the present invention is in the first place a method for treating banana leaf spot diseases, characterized in that an effective and non-phytotoxic dose of a compound A, selected from
salts of a mono-alkyl phosphite and of a mono-, di- or trivalent metal cation, such as Fosetyl-Al, or
- Phosphorous acid and its alkali or alkaline earth salts
Fosetyl-Al is aluminum tris-O-phosphonate, described in "The Pesticide Manual" 9th edition, by Charles R. Worthing and Raymond J.

Hance published by the British Crop Protection Council.

 The dose of compound A applied is likely to vary within wide limits depending on the degree of infestation of the disease, the climatic conditions and the frequency of treatments performed. For convenience, this dose is expressed as equivalent weight of phosphorous acid, formula H3PO3, applied per hectare. This dose is in general between 350 and 2450 g / ha, preferably between 630 and 2100 g / ha. The calculation from this dose of the dose of a specific compound A is conveniently carried out taking into account the molar mass of said compound and that of phosphorous acid. In the case where the specific compound A is a salt of a mono-alkyl phosphite and a di- or tri-valent metal cation, it is also necessary to take into consideration the number of valence of the corresponding cation.

According to an advantageous variant of the invention, the compound A applied is Fosetyl-Al. In this case, the dose of compound A, expressed in weight of
Fosetyl-Al applied per hectare is between 500 and 3500 g / ha, preferably between 900 and 3000 g / ha.

According to a preferred variant of the invention, in the treatment method according to the invention, in addition to an effective and non-phytotoxic dose of compound A, an effective and non-phytotoxic dose of a compound B having an inhibiting action is also applied. of the biosynthesis of ergosterol and selected from
a triazole compound chosen from bromuconazole, propiconazole, triadimenol, flusilazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, epoxiconazole, metconazole, difenoconazole, fluquinconazole; or
fenarimol, fenpropidine or tridemorph.

 Bromuconazole is 1- [4-bromo-2- (2,4-dichlorophenyl) tetrahydro-2-furanylmethyl] 1H-1,2,4-triazole, which is described in European Patent Application 0246982. Epoxiconazole is (2RS, 3SR) -1- [3- (2-chlorophenyl) -2- (4-fluorophenyl) oxiran-2-ylmethyl] -1H-1,2,4-triazole, which is described in at least one of the 2 European Patent Applications 94564 or 196038. Metconazole is (RS, SURS; RS, SSR) -5- (4-chlorobenzyl) -2,2-dimethyl-1- (1H-1,2,4-triazole). 1-ylmethyl) cyclopentanol, which is described in European Patent Application 0267778. Fluquinconazole is 3- (2,4-dichlorophenyl) -6-fluoro-2- (1H-1,2,4-triazol-1-yl) quinazolin4- (3H) -one, which may be prepared according to a process described in European Patent Application EP 183458.

The other active ingredients, previously mentioned in the definition of B, are described in the book: "The Pesticide Manual" 9th edition, by Charles R. Worthing and Raymond J. Hance published by the British
Crop Protection Council. Thus, propiconazole is 1- [2- (2,4-dichlorophenyl) -4-propyl-1,3-oxolan-2-yl] methyl] -1H-1,2,4-triazole. Triadimenol is (1 Rs, 2RS, 1RS, 2SR) -1- (4-chlorophenoxy) -3,3-dimethyl-1- (1H-1,2,4-triazol-1-yl) butan-2-ol. Flusilazole is 1 - [[bis (4-fluorophenyl) (methyl) silyl] methyl] -1H-1,2,4-triazole. Hexaconazole is (RS) -2- (2,4-dichlorophenyl) -1- (1H-1,2,4-triazol-1-yl) hexan-2-ol. Cyproconazole is (2RS, 3RS, 2RS, 3SR) -2- (4-chlorophenyl) -3-cyclopropyl-1- (1H-1,2,4-triazol-1-yl) butan-2-ol. Diniconazole is (E) - (RS) -1- (2,4-dichlorophenyl) 4,4-dimethyl-2- (1H-1,2,4-triazol-1-yl) pent-1-en-3- ol. Tebuconazole is (RS) -1- (4-chlorophenyl) -4-dimethyl-3- (1H-1,2,4-triazol-1-ylmethyl) pentan-3-ol. Difenoconazole is cis, trans-3-chloro4- [4-methyl-2- (1H-1,2,4-triazol-1-ylmethyl) -1,3-dioxolan-2-yl phenyl 4chlorophenyl ether, fenarimol is (2-chlorophenyl) - (4-chlorophenyl) -5-pyrimidinemethanol, fenpropidine is (RS) -1- [3- (4-tert-butylphenyl) -2-methylpropyl] piperidine. The tridemorph is 2,6-dimethyl-4-tridecylmorpholine.

 According to a more preferred variant of the invention, compound B used in the process according to the invention is chosen from bromuconazole or propiconazole.

 According to a more particularly preferred variant of the invention, the compound B used in the process according to the invention is bromuconazole.

 When, according to a preferred variant of the invention, the compound A applied in the process according to the invention is Fosetyl-Al and when, also according to a preferred variant of the invention, the compound B used is bromuconazole, the effective and non-phytotoxic dose of osteyl-Al is between 500 and 2000 g / ha, preferably between 750 and 1500 g / ha, and the effective and non-phytotoxic dose of bromuconazole is between 50 and 200 g / ha, preferably between 75 and 150 g / ha.

 For their practical application on banana plants, compound A on the one hand and / or the mixture of compounds A and B on the other hand, are used in the form of the fungicidal composition which is described more precisely in this invention. following.

The subject of the present invention is also a fungicidal composition which comprises at least one compound A chosen from:
salts of a mono-alkyl phosphite and of a mono-, di- or trivalent metal cation, such as Fosetyl-Al, or
- phosphorous acid and its alkali or alkaline earth salts
and at least one compound B having an action of inhibition of the biosynthesis of ergosterol and selected from
a triazole compound chosen from bromuconazole, propiconazole, triadimenol, flusilazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, epoxiconazole, metconazole, difenoconazole, fluquinconazole; or
fenarimol, fenpropidine or tridemorph.

 This composition is effective for the treatment of Sigatoka leaf spot without being phytotoxic.

 According to a preferred variant of the composition according to the invention, the molar ratio A / B of the compounds A and B included in the composition according to the invention is generally between 8 and 128, preferably between 16 and 64. According to the According to the present invention, the molar ratio A / B is the ratio calculated as follows. The numerator of this ratio is equal to the number of moles of compound A multiplied by the number of moles of phosphorous acid resulting from the hydrolysis of one mole of compound A. Phosphorous acid is the compound of formula H3PO3. The denominator of this ratio is equal to the number of moles of compound B.

 According to a more preferred variant of the composition according to the invention, compound B is bromuconazole.

 According to a still more preferred variant of the composition according to the invention, the compound A is Fosetyl-Al.

 The composition resulting from these last two variants taken simultaneously is particularly advantageous for its high performance with respect to Sigatoka disease and for its selectivity with respect to this crop. It also allows to observe remarkable synergistic effects.

This composition advantageously has a weight ratio Fosetyl
Al / bromuconazole between 2.5 and 40, preferably between 5 and 20.

 The fungicidal composition used in the treatment method according to the invention usually contains 0.5 to 95% of compound A, when it is applied as the sole fungicidal active ingredient. The fungicidal composition comprising the compounds A and B and object of the invention also comprises from 0.5 to 95% of mixture of A and B.

 In the latter case, it may be the concentrated composition that is to say the commercial product combining the two active ingredients. It can also be the diluted composition ready to be sprayed on the crop to be treated. Dilution with water (or in some cases dilution with oil or a mixture comprising water and oil) can then be performed either from a commercial concentrate composition containing the two active ingredients (This mixture is called "ready-to-use" or "ready mix", in English), or by means of the extemporaneous mixture (called "tank mix") of two commercial concentrated compositions each containing an active ingredient.

 The fungicidal composition may further include any of the usual additives or adjuvants of the phytosanitary compositions, including carriers, surfactants, adhesion promoters and fluent agents.

 By the term "carrier", in the present description, means an organic or inorganic material, natural or synthetic, with which the active ingredients are associated to facilitate their application to the plant. This support is therefore generally inert and must be acceptable in agriculture, especially on the treated plant. The support 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 emulsifier, dispersant or wetting agent of ionic or nonionic type. There may be mentioned, for example, salts of polyacrylic acids, salts of lignosulfonic acids, salts of phenolsulphonic or naphthalenesulphonic acids, polycondensates of ethylene oxide with fatty alcohols or with fatty acids or with fatty amines. substituted phenols (especially alkylphenols or arylphenols), salts of sulfosuccinic acid esters, 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 ingredients in water and their good application to plants.

 This composition may also contain all kinds of other ingredients such as, for example, protective colloids, adhesives, thickeners, thixotropic agents, penetration agents, stabilizers, sequestering agents, pigments, dyes, polymers .

 More generally, the composition that can be used in the process according to the invention and / or object of the invention can include all the solid or liquid additives corresponding to the usual techniques for the formulation of plant protection products.

 This composition may 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 convenience of implementation and because of their simplicity of manufacture.

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

 Wettable powders (or spray powders) as well as dispersible granules usually contain from 20 to 95% active ingredients, and in addition to the solid carrier, from 0 to 5% of a wetting agent, from 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, penetrating agents, adhesives, or anti-caking, coloring agents 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 and pastes.

 The emulsifiable or soluble concentrates most often comprise 10 to 80% of active materials, the emulsions or solutions ready for application containing, for their part, 0.01 to 20% of active ingredients. In addition to the solvent, the emulsifiable concentrates may contain, when necessary, 2 to 20% of appropriate additives such as stabilizers, surfactants, penetrating agents, corrosion inhibitors, dyes or adhesives previously cited. From these concentrates, it is possible to obtain, by dilution with water, emulsions of any desired concentration, which are particularly suitable for application to the aerial parts of the plant to be treated.

As already mentioned, 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 may be of the water-in-oil or oil-in-water type and may have a thick consistency such as that of a "mayonnaise".

 Concentrated suspensions, also applicable in spraying, are a stable fluid product, not giving rise to thickening or sediment formation after storage, and they usually contain from 10 to 75% of active ingredients, 0.5 15% surfactants, 0.1 to 10% thixotropic agents, 0 to 10% of suitable additives, such as pigments, dyes, defoamers, corrosion inhibitors, stabilizers, penetrants and adhesives and, as carrier, water or an organic liquid in which the active ingredients are little or not soluble: some organic solids or inorganic salts may be dissolved in the carrier to help prevent sedimentation or as antifreezes for water.

 The composition described above is prepared according to methods known per se.

 Thus, in order to obtain the spraying powders or wettable powders, the active ingredients are intimately mixed in appropriate mixers with the additional substances and ground with mills or other grinders. Spray powders are thus obtained, the wettability and suspension of which 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.

 In place of the wettable powders, it is possible to produce concentrated pastes or suspensions. The conditions and methods of production and use of these pastes are similar to those of wettable powders or powders to be sprayed, part of the necessary grinding operation being simply performed in a liquid medium.

 The dispersible granules are usually prepared by agglomeration or extrusion or compaction, in suitable granulation systems, of wettable powder compositions. The granules for dry spreading are usually obtained by impregnating a granulated support with a solution or an emulsion of the active ingredients.

 The following examples are given purely by way of illustration and without limitation of the advantageous properties of the process and of the composition according to the invention.

Example 1 In Vivo Test of a Composition Comprising Fosetyl-Al on Mycosphaerella Musicola Responsible for Yellow Sigatoka of Banana
A wettable powder of Fosetyl-Al comprising the following ingredients (doses expressed in% w / w)
Fosetyl-Al 80%
60% ethoxylated alcohol impregnated on precipitated silica 2.5%
sodium lignosulfonate 3%
2.5% ethoxylated polyarylphenol
50% impregnated fatty alcohol on precipitated silica 2%
silico aluminate 10%
The test is carried out on a plot located in a banana plantation, in a tropical zone.

 The test composition is applied by spraying on the banana leaves at the beginning of the rainy season corresponding to the period when Mycosphaerella musicola infestation is likely to occur. Dosages of acetyl-Al applied are shown in the table below.

 This treatment is repeated 9 times, each of the applications being separated by a time interval of 14 days.

 The results are observed 14 days after the 10th treatment.

 For this purpose, the foliar surface contaminated by the disease, expressed in% of the total leaf area, is determined by a visual check of the percentage of necrotic surface (yellow and brown zones) on all the banana leaves, compared to a plant. banana (not receiving fungicide treatment).

The results are summarized in the table below.

<Tb>

Dose <SEP> of <SEP> Fosetyl-Al <SEP> applied <SEP> Surface <SEP> foliar <SEP> contaminated <SEP> (in <SEP>%)
<tb><SEP> (in <SEP> g / ha)
<tb><SEP> 1000 <SEP> 30.3
<tb><SEP> 2000 <SEP> 32.8
<tb><SEP> 3000 <SEP> 29.7
<tb><SEP> Plant <SEP> Plant <SEP> Control <SEP> I <SEP> 56.3
<Tb>
Following a treatment with a commercial formulation of chiorothalonil, applied at a rate of 2000 g / ha and with the same protocol, a contaminated leaf area equal to 34.7% was observed.

 These results show a very good efficacy of Fosetyl-Al against Sigatoka leaf spot.

Example: In vivo test of a composition comprising the dipotassium salt of phosphorous acid on Mycosphaerella musicola responsible for yellow Sigatoka of banana trees
A dipotassium salt solution of phosphorous acid is used at a concentration of 200 g / l (expressed as phosphorous acid equivalent).

 The test is carried out on a plot located in a banana plantation, in a tropical zone.

 The composition tested is applied by spraying on the banana leaves at the beginning of the rainy season corresponding to the period when the infection with Mycosphaerella musicola is likely to occur. The dipotassium salt dose of the phosphorous acid applied is 650 g / ha (expressed as phosphorous acid equivalent).

 This treatment is repeated 4, 5 or 6 times, each of the applications being separated by a time interval of 21 days.

 For the observation of the results, the leaf surface contaminated by the disease, expressed in% of the total leaf area, is determined by a visual check of the percentage of necrotic surface (yellow and brown zones) on the 5th or 6th leaf of the leaves. banana (respectively F5 or F6), compared to a control banana plant (not receiving fungicide treatment).

 The results are summarized in the table below.

The abbreviations used in this table have the following meaning
19DAT5: result observed 19 days after the 5th treatment
12DAT6: result observed 12 days after the 6th treatment;
20DAT7: result observed 20 days after the 7th treatment.

Contaminated leaf area results (in%)

<tb><SEP> 19DAT5 <SEP> 12DAT6 <SEP> 20DAT7
<tb><SEP> F5 <SEP> F6 <SEP> F5 <SEP> F6 <SEP> F5
<tb><SEP> Plant <SEP> Treated <SEP> 6 <SEP> 30 <SEP> 15 <SEP> 37.5 <SEP> 37
<tb> | Plant <SEP> control <SEP> d <SEP> 24 <SEP> d <SEP> 43 <SEP> I <SEP><SEP> 39 <SEP> 43 <SEP> 58 <SEP> 58 <SEP > 69 <SEP> j
<Tb>
These results show a very good efficacy of the dipotassium salt of phosphorous acid against banana leaf spot.

Example 3 In Vivo Test of a Composition Comprising a Mixture of
Fosetyl-Al and bromuconazole on Mycosphaerella musicola responsible for yellow Sigatoka banana
One uses either a composition comprising Fosetyl-Al, in the form of a wettable powder, or a composition comprising bromuconazole in the form of an emulsifiable concentrate, or else a composition according to the invention, obtained by mixing the two preceding compositions. The same composition as in Example 1 is used for Fosetyl-Al. The composition used for bromuconazole is the following (doses expressed in% w / w):
bromuconazole 20%
ethoxylated fatty alcohol: 9%
9% ethoxylated castor oil
N. methylpyrrolidone 18%
Acetophenone 44%
The test is carried out on a plot located in a plantation of
banana trees, in tropical zone.

 The compositions tested are applied by spraying on the banana leaves at the beginning of the rainy season corresponding to the period when the Mycosphaerella musicola infestation is likely to occur.

The doses of active ingredients applied (alone or as a mixture) are 1000 g / ha for Fosetyl-Al and 75 g / ha for Bromuconazole.

 This treatment is repeated 5 times, each of the applications being separated by a time interval of 3 weeks.

 We observe the results (initially: T1) 8 days and (in a second time: T2) 14 days after proceeding to the 5th treatment. For this purpose, the fungicidal efficacy, expressed in%, is determined by a visual check of the percentage of necrotic surface (yellow and brown zones) on the 5th and 7th leaves (called respectively F5 and F7), compared with a banana plant. control (not receiving fungicide treatment).

 The results are summarized in the table below.

Fungicide efficacy results (in%)

<tb><SEP> Active <SEP> material (s) <SEP> Observation <SEP> to <SEP> T1 <SEP> Observation <SEP> to <SEP> T2
<tb><SEP> F5 <SEP>[<SEP> F7 <SEP> F5 <SEP> F7
<tb><SEP> fosetyl-aluminum <SEP> 33 <SEP> 20 <SEP> 45 <SEP> 17
<tb><SEP> bromuconazole <SEP> 21 <SEP> 22 <SEP> 20 <SEP> 9
<tb> fosetyl-aluminum <SEP> + <SEP> bromuconazole <SEP> ~ <SEP><SEP> 56 <SEP> 46 <SEP> 81 <SEP> 24
<Tb>
These results show the very good fungicidal efficacy of the composition according to the invention, and in particular a remarkable degree of synergism as defined by Colby SR in an article entitled "Calculation of synergistic and antagonistic responses of herbicide combinations" published in Weeds magazine, 1967, 15, p. 20-22.

Claims (14)

 A method for treating banana leaf spot diseases, characterized in that an effective and non-phytotoxic dose of a compound A selected from:  salts of a mono-alkyl phosphite and a mono-, di- or trivalent metal cation, such as Fosetyl-Al, or  - Phosphorous acid and its alkali or alkaline earth salts  2. Method according to claim 1, characterized in that the dose of compound A is between 350 and 2450 g / ha, preferably between 630 and 2100 g / ha.  3. Method according to one of claims 1 or 2, characterized in that the compound A is Fosetyl-Al.  4. Method according to claim 3, characterized in that the dose of Fosetyl-Al is between 500 and 3500 g / ha, preferably between 900 and 3000 g / ha.  5. Method according to one of claims 1 to 4, characterized in that it also applies an effective and non-phytotoxic dose of a compound B having an action of inhibition of the biosynthesis of ergosterol and selected from  a triazole compound chosen from bromuconazole, propiconazole, triadimenol, flusilazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, epoxiconazole, metconazole, difenoconazole, fluquinconazole; or  fenarimol, fenpropidine or tridemorph.  6. Process according to claim 5, characterized in that compound B is chosen from bromuconazole or propiconazole.  7. Method according to one of claims 5 or 6, characterized in that the compound B is bromuconazole.  8. Process according to claims 4 and 7, characterized in that the effective and non-phytotoxic dose of osteyl-Al is between 500 and 2000 g / ha, preferably between 750 and 1500 g / ha and the effective and non-phytotoxic dose. bromuconazole is between 50 and 200 g / ha, preferably between 75 and 150 g / ha.  9. Fungicidal composition comprising at least one compound A, chosen from:  salts of a mono-alkyl phosphite and of a mono-, di- or trivalent metal cation, such as Fosetyl-Al, or  - phosphorous acid and its alkali or alkaline earth salts  and at least one compound B having an action of inhibition of the biosynthesis of ergosterol and selected from  a triazole compound chosen from bromuconazole, propiconazole, triadimenol, flusilazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, epoxiconazole, metconazole, difenoconazole, fluquinconazole; or  fenarimol, fenpropidine or tridemorph.  10. Fungicidal composition according to claim 9, characterized in that the molar ratio A / B is between 8 and 128, preferably between 16 and 64.  11. Fungicidal composition according to one of claims 9 or 10, characterized in that the compound B is bromuconazole.  12. Fungicidal composition according to one of claims 9 to 11, characterized in that the compound A is Fosetyl-Al.  13. Fungicidal composition according to claims 11 and 12, characterized in that the weight ratio of osteyl-Al / bromuconazole is between 2.5 and 40, preferably between 5 and 20.  14. Fungicidal composition according to one of claims 9 to 12, characterized in that it contains from 0.5 to 95% of mixture of compounds A and B.