OA10279A - Method for improving the health of banana trees - 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

I Method to improve the health of banana trees.

The present invention relates to a method for improving banana health, and an agrochemical composition having the same purpose.

The health of banana trees can be affected by various factors, mainly the presence of diseases such as Fusarium wilt or Leaf spot or the presence of harmful nematodes.

In particular, Sigatoka leaf spot disease, caused by the fungi Mycosphaerella musicola and / or Mycosphaerella fijiensis, causes yellow and / or brown necrosis to appear on the leaves, followed by a reduction in the number of plant leaves. This results in significant losses in the fruit yield of the contaminated plantations.

Similarly, nematodes cause a weakening of the plant, detrimental to the importance of fruit yield.

Cacosporosis is known to be effective against bananas for products such as mancozeb or chlorothalonil. It is always desirable, however, to extend the possibilities of choice offered to the farmer so that he finds the solution best adapted to his particular problem. The object of the invention is therefore a method for improving the health of banana trees, and more precisely a method for: - combating, as a preventive and / or curative measure, sbanan leaf spot diseases, and / or - protecting banana plants against nematodes . It has now been found that these objects can be achieved in whole or in part by the method of treatment according to the present invention.

The object of the present invention is first and foremost a method for improving the health of banana plants at a place, characterized in that an effective and non-phytotoxic dose of a compound A, selected from: 010279 - salts, is applied at said place. mono-alkyl phosphite and a metallo-, di- or trivalent metal cation, such as fosetyl-Al, or phosphorous acid and its alkali or alkaline earth salts.

Compound A is generally applied to the aerial parts of banana plants.

Fosetyl-Al is aluminum tris-O-ethyl phosphonate, described in "The Pesticide Manual" 9th edition, by Charles R. Worthing and Raymond J. Hope published by the British Crop Protection Council.

In the present text, including the claims, an alkyl group is usually a straight or branched chain alkyl group having 1 to 4 carbon atoms.

Compound A can be prepared using known methods or paranalogy with known methods.

The dose of compound A applied is likely to vary within the limits limits according to the climatic conditions, the culture conditions, and the frequency of the treatments carried out. For convenience, this dose is expressed as equivalent weight of phosphorous acid, formula H3PO3, applied per hectare.This dose is generally between 0.350 and 10.4 kg / ha, preferably between 0.630 and 7 kg / ha. Calculation from this dose of the dose of a specific compound A is conveniently done taking into account the massemolar 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, the valence number of the corresponding cation should also be considered.

According to an advantageous variant of the invention, the compound A applied is fosetyl-Al. In this case, the dose of compound A, expressed by weight of deosetyl-Al applied per hectare, is between 0.500 and 15 kg / ha, preferably between 0.900 and 10 kg / ha.

According to a preferred variant of the invention, the banana trees are affected or susceptible to be affected by Sigatoka.

In this case the dose of compound A is also related to the degree of infestation of the disease. This dose, also expressed in equivalent weight of phosphorous acid applied per hectare is generally between 350 and 2450 g / ha, preferably between 630 and 2100 g / ha. 3 Ο ί V, 279

When, according to an advantageous variant of the invention, the compound A applied is fosetyl-Al, the dose of compound A, expressed by weight of fosetyl-A1 applied per hectare, is between 500 and 3500 g / ha, preferably between 900 and and 3000 g / ha.

According to another preferred variant of the invention, the banana trees are attacked or likely to be attacked by the nematodes. These nematodes are generally phytophagous nematodes of the order Tylenchids (includingAphelenchidae, Aphelenchoïdae, Paraphlenchidae, Tylenchidae,

Neotylenchidae, Hoplolaimdidae, Tylenchulidae, Criconematidae,

Heteroderidae) and the order Dorylaimidae (especially Dorylaimidae, Longidoridae, Trichodoridae '). Compound A is particularly effective against nematodes of the order of Tylenchides selected from: Radopholussimilis, Pratylenchus spp., Zygotylenchus tasmaninae, Hoplolaimus spp., Helicotylenchus multicinctus, Helicotylenchus spp., Meloidogyne spp., Rotylenchulus reniformis.

According to this variant, the dose of compound A, expressed as the equivalent weight of phosphorous acid is advantageously between 0.35 and 10.4 kg / ha, preferably between 1.4 and 7 kg / ha.

When, according to an advantageous variant of the invention, the compound A applied is fosetyl-Al, the dose of compound A, expressed by weight of fosetyl-Al applied per hectare, is between 0.5 and 15 kg / ha, preferably between 2 and 10 kg / ha.

Radopholus similis in particular causes a lot of damage to banana trees. The method according to the invention is particularly effective against ceparasite.

Compound A may be applied by spraying on the aerial parts of the banana plants, by any means known per se such as by a spray or by air. It can also be applied by watering around plants. According to a preferred variant of the invention, compound A is applied by injection.

This injection can be carried out in the pseudostem section of banana, just after harvesting bananas, by any means known per se. Pseudo-trunk of the banana means the trunk of the banana plant, which is non-woody. Pseudo-trunk section, therefore, means the section obtained by cutting, at the time of banana harvesting, the pseudo-trunk at a certain height above the ground (between 1 and 2 m). injection application of the compound A in this section of the pseudo-trunk can also be done by simply pouring a treatment liquid comprisingA in a cavity of the order of 5 cm deep, arranged in thisisection. This technique of application makes it possible to reduce the frequency of the treatments by carrying out only 1 treatment during the period separating the production of 2 crops of bananas by the same plant. It also makes it possible to operate this treatment at the time of the banana harvest on the plant. This results in significant time savings for farmers. The injection can also be carried out in the pseudostem that develops after the aforementioned pseudo-trunk, and which will produce the next crop of bananas. The subject of the invention is also the use of compound A for the manufacture of agrochemical compositions intended to: - fight, as a preventive and / or curative measure, sbanan leaf spot diseases, and / or - protect banana plants against nematodes.

For its practical application on banana plants, the compound A is in fact implemented in the form of an agrochemical composition.

This agrochemical composition usually comprises from 0.5 to 95% of compound A in combination with an agriculturally acceptable carrier. Unless otherwise indicated, the percentages given in this text are percentages by weight.

It may furthermore comprise all the usual additives or adjuvants of plant protection compositions, in particular 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 combined 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 emulsifying, dispersing or wetting agent of ionic or nonionic type. There may be mentioned, for example, polyacrylic acid salts, lignosulfonic acid salts, phenolsulphonic or naphthalenesulphonic acid salts, ethylene oxide polycondensates on fatty alcohols or on fatty acids or on fatty amines, and phenols. substituted (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 any other kind of 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 any solid or liquid additives corresponding to the usual techniques for the formulation of phytosanitary products.

This composition may be in solid, gelled or liquid form, and in the latter case in the form of solutions or suspensions. 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 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 20 to 95% active ingredients, and in addition to the solid carrier, from 0 to 5% wetting agent, from 3 to 10% by weight. 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 the solutions, in particular the water-soluble concentrates, the concentrated suspensions, the pastes.

Soluble concentrates most often comprise 10 to 80% active matter, the solutions ready for application containing, for their part, 0.01 to 40% of active ingredient. As already mentioned, aqueous dispersions, for example the compositions obtained by diluting a wettable powder according to the invention with water, are included in the general scope of the present invention.

The concentrated suspensions, also applicable in spraying, are a stable fluid product, not giving rise to a thickening or forming of a sediment after storage, and they usually contain from 10 to 75% of active ingredients, from 0.5 to 15% by weight. % of surfactants, from 0.1 to 10% thixotropic agents, from 0 to 10% of suitable additives, such as pigments, descolers, antifoams, corrosion inhibitors, stabilizers, penetrating agents and adhesives and, as carrier, water or an organic liquid in which the active ingredients are little or not soluble: certain organic solid materials or inorganic salts may be dissolved in the supports to help prevent sedimentation or as antifreezes for the water.

The compositions described above are prepared according toprocesses known per se.

Thus, in order to obtain the spraying powders or wettable powders, the active ingredients are intimately mixed in suitable mixers with the additional substances and ground with mills or other grinders. This results in powders for spraying 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. 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 the wettable powders or powders to 7 ϋ10279 pulverize, part of the necessary grinding operation is simply carried out in a liquid medium.

The dispersible granules are usually prepared by agglomeration or extrusion or compaction, in suitable granulation systems, wettable powder type decompositions. 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 nonlimiting of the advantageous properties of the method according to the invention.

Example 1 In Vivo Application of Fosetyl-Al on Mycosphaerellamusicola Responsible for Yellow Sigatoka of Banana:

A wettable powder of fosetyl-Al comprising the following ingredients (doses expressed in% weight / weight) is used: fosetyl-Al alcohol ethoxylated impregnated to 60% on precipitated silica sodium lignosulfonate polyarylphenol ethoxylated 50% impregnated fatty alcohol on precipitated silica silico aluminate 80% 2,5% 3% 2,5% 2% 10% The test is carried out on a plot located in a plantation of banana trees, in tropical zone.

The test composition is applied by spraying on the leaves of the tree from the beginning of the rainy season corresponding to the period when infection with Mycosphaerella musicola is likely to occur. The doses of fosetyl-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 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 all banana leaves, compared with banana plant control (not receiving fungicide treatment).

The results are collated in the following table.

Application rate of fosetyl-Al (in g / ha) Contaminated leaf area (in%) 1000 30.3 2000 32.8 3000 29.7

Control plant 56.3 Following treatment with a commercial formulation of chlorothalonil, 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 the Sigatoka disease of banana trees.

Example 2 In Vivo Application of the Dipotassium Salt of Phosphorous Acid on Mycosphaerella Musicola Responsible for Yellow Sigatoka of Banana:

A dipotassium salt solution of phosphorous acid with a concentration of 200 g / l (expressed as phosphorous acid equivalent) is used. 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 dose 9 U 1 G 2 7 9 of dipotassium salt 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 foliar surface contaminated by the disease, expressed in% of the total leaf area, is determined by a visual control of the percentage of necrotic surface (yellow and brown zones) on the 5th or 6th leaf of the banana trees (noted respectively F5 or F6), compared to a control banana plant (which has not received fungicidal 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 (%) 19DAT5 12DAT6 20DAT7 F5 F6 F5 F6 F5 Plant treated 6 30 15 37.5 37 Plant control 24 43 39 58 69

These results show a very good efficacy of the dipotassium salt of phosphorous acid against banana leaf spot.

Example 3: Application by injection of fosetyl-Al and effect on banana nematodes: The test is conducted on a banana plantation (Cavendish variety) which has reached a stage of regular fruit production.

This plantation is treated 70 days before harvest by injection of Fosetyl-Al suspension into the banana pseudostem, corresponding to a dose of 6.4 kg / ha. At harvest, a soil volume of 20 dm3 is taken in which 25 g of healthy roots are isolated, from which the live nematodes are extracted by distillation with water and filtration on sieves with a mesh size of 40 μm. Live nematodes are nematodes of the species Radopholus similis and are counted under the microscope. The number of nematodes is indicated for 100 g of roots.

There are 4000 living nematodes.

In comparison, the number of live nematodes of the same species, counted identically for bananas not treated with Fosetyl-Al, is 13200. The application of Fosetyl-Al has therefore reduced by 70% the number of nematodes parasitizing the banana plants.

Example 4: Foliar Application of Fosetyl-Al and Effects on Banana Nematodes: The test is conducted on a plantation of young banana plants (GiantCavendish variety).

Three months after planting these plants, a foliar spray treatment of a suspension of fosetyl-Al at the indicated dose in kg / ha is given in the table below.

This treatment is repeated after 10 days and after 40 days.

The results are observed 3 weeks after the last treatment, as in Example 3.

The results are collated in the following table with the indication of efficacy calculated as the difference between the number of nematodes measured for the control test and the same number corresponding to the application of a fixed dose of fosetyl. -Al, ie N, the said difference being divided by T.

Number of nematodes of the species Radopholussimilis per 100 g of root Efficacy of treatment (in%) Dose of 2.5 9800 52 fosetyl-Al 5 10000 51 (kg / ha) 10 10000 51

Control test 20500

Example 5 Application of Fosetyl-Al by Watering Feet and Effect on Nematodes: The test is conducted on a banana plantation (Cavendish variety) which has reached a stage of regular fruit production.

The feet of the banana are watered with a suspension of Osetyl-Al, corresponding to a dose expressed in kg / ha in the table below.

The results are observed 60 days after the treatment, as in Example 3.

The results are collated in the following table with the indication of the efficiency calculated as in Example 4. 12

Number of nematodes of the species Radopholussimilis per 100 g of roots Efficiency of the treatment (%) Dose of fosetyl-Al 3.2 6000 83 (kg / ha) 4 8000 77 4.8 9000 75 5,6 7000 81 6, 4 1000 97

Control test 36000

Examples 3 to 5 therefore show a real decrease in the number of nematodes of the species Radopholus similis, resulting from the banana application of fosetyl-Al.

Claims (15)

13 010279 CLAIMS 1. A method for improving the health of banana plants in a place, characterized in that an effective and nonphytotoxic dose of a compound A, chosen from: - the salts of a mono-alkyl phosphite, is applied to the said place; and a metallo-di- or tri-valent 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 compound A is applied to the aerial parts of the plants. 3. Method according to one of claims 1 or 2, characterized in thata dose of compound A, expressed in weight equivalent of phosphorous acid, iscomprise between 0.35 and 10.4 kg / ha, preferably between 0.63 and 7 kg / ha. 4. Method according to one of claims 1 to 3, characterized in that compound A is fosetyl-Al. 5. Method according to claim 4, characterized in that the dose of deosetyl-Al is between 0.500 and 15 kg / ha, preferably between 0.900 and 10kg / ha. 6. Method according to one of claims 1 to 5, characterized in that banana are affected or likely to be affected by Sigatoka disease 7. Method according to claim 6, characterized in that the decomposed dose A, expressed in weight equivalent of phosphorous acid, is between 350 and 2450 g / ha, preferably between 630 and 2100 g / ha. 14 8. Method according to one of claims 6 or 7, characterized in that compound A is fosetyl-Al, applied at a dose of between 500 and 3500 g / ha, preferably between 900 and 3000 g / ha. 9. Method according to one of claims 1 to 5, characterized in that banana trees are attacked or likely to be attacked by nematodes. 10. Method according to claim 9, characterized in that the decomposed dose A, expressed in weight equivalent of phosphorous acid, is between 0.350 and 10.4 kg / ha, preferably between 1.4 and 7 kg / ha. 11. Method according to one of claims 9 or 10, characterized in that 3 compound A is fosetyl-Al, applied at a dose of between 0.5 and 15 kg / ha, preferably between 2 and 10 kg / ha. . 12. Method according to one of claims 9 to 11, characterized in that the nematodes are of the species Radopholus similis. 13. Method according to one of claims 1 to 12, characterized in that compound A is applied by injection into the pseudostem of banana plants. 14. Method according to one of claims 1 to 12, characterized in that the compound A is applied by watering around the banana plants. 15. Use of the compound A as defined in claim 1, for the manufacture of agrochemical compositions for: - a preventive and / or curative control of cercosporiose desbananiers, and / or - protect the banana against nematodes.