WO2024246169A1 - Plant treatment method - Google Patents

Abstract

The invention relates to the field of agriculture and to a treatment for plants that is based on gamma-mangostin and a plant health-promoting compound, wherein the action of the plant health-promoting compound is improved by co-administration of the gamma-mangostin.

Description

METHOD OF TREATMENT OF PLANTS

The invention relates to the field of agriculture and to a treatment of plants based on an antifungal compound, in particular phosphonate compounds (salts of phosphorous acid) or chitosan in which the action of this compound is improved by co-administration, in particular of an extract of Garcinia mangostana.

Plants are subject to many fungal diseases that can cause significant yield and therefore economic losses.

As mentioned on the site wiki.tripleperformance.fr (Using_phosphonates_in_the_fight_against_mildiou), phosphonates are salts of phosphorous acid, derived from phosphate rocks. Phosphonates have fungicidal properties. Many trials in different countries have shown the effectiveness of phosphonates against many cryptogamic diseases: Downy mildew of grapevines, Phytophtora of fruit trees, Pythium, etc. The use of phosphonates (potassium phosphonate, disodium phosphonate) constitutes a particularly interesting alternative to copper given their effectiveness. Biocontrol phosphonates have a dual activity: fungicide and stimulator of plant defenses. They thus act directly on the pathogen (main fungicidal effect) but also indirectly by stimulating the defenses of plants by activating phyto-alexins in particular. Biocontrol phosphonates are used preventively. In case of low pressure, the use of phosphonates alone is possible but it is however recommended to associate them with a partner fungicide of contact at a reduced dose, in order to complete the efficacy on leaves and to ensure an optimal protection of the plants. The management of the rates between two applications is just as important as with any other fungicide, in particular in case of heavy precipitation. However, phosphonate sprays systematically result in residues of phosphorous acid, in particular in wines. These residues are lower than the MRLs and are not dangerous for the consumer. In addition, these products are prohibited in organic farming. These products are commonly used at doses resulting in quantities of phosphonates of 1.5 to 3 kg per hectare, representing concentrations that can vary from 2.5 g/L to 30 g/L on average. Phosphonates (in particular potassium phosphonates) are authorised for marketing in France, in particular for the following applications, with maximum recommended doses and number of applications (when phosphonates are used alone, they are at a concentration of 720-755 g/L):

Solanaceae (including tomatoes and eggplants): mildew(s), 2.5-4 L/ha, 3-5 applications

Pome fruits (apple trees, pear trees, quince trees, etc.): scab, 1.9-2.5 L/ha, 6 applications

Chicory, 3.5 L/ha 4 applications

Cucurbits with edible skin, 3.5 L/ha 5 applications

Cucurbits with inedible skin, 3.5 L/ha 3 applications

Lettuce, 3.5 L/ha 4 applications

Peppers: mildew(s), 2.5-4 L/ha 3-5 applications

Vine: downy mildew(s) 2.5-4 L/ha 2-5 applications; black rot (Guignardia bidwellii) 4 L/ha 4 applications; Excoriosis (Phomopsis viticola) 3 L/ha

2 applications; parasitic red mite (Pseudopezicula tracheiphila), 4 L/ha

5 applications

Fruit crops (such as blueberry, currant, gooseberry, peach and nectarine): Fungi (Pythiaceae, including Phytophthora spp), 2.5-4 L/ha 3 applications (aerial parts); 10 L/ha 3 applications

(ground)

- Citrus (orange, lemon, grapefruit, mandarin, clementine and lime): Phytophthora citrophthora; collar canker (Phytophthora cactorurrf) 5-8.75 L/ha 1-2 applications; Fungi (Pythiaceae) 4-6 L/ha 3-4 applications Wheat: Septoria; 4 L/ha 2 applications (aerial parts)

Strawberry: mildew(s) 2.5 L/ha 3 applications

Raspberry: Mushrooms (Pythiaceae) 2.5 L/ha 3 applications

Potato: mildew(s) 4 L/ha 3 applications

Nuts: 4 L/ha 6 applications

Pomegranate: 2.4 L/ha 3 applications

Olive tree: leaf diseases 2.5 L/ha 3 applications

Flower crops and green plants: mildew(s)

Indoor plants and balconies: mildew(s) Rose bushes: mildew(s) 0.5 L/10 ^m2 3 applications

It is of interest to find solutions to reduce the use of phosphonates while maintaining effective protection of crops against fungal diseases.

Chitosan (or chitosan) is a natural polymer obtained by the partial deacetylation of chitin that is now widely used in many fields of application. Given its biodegradable and non-toxic nature, chitosan represents a promising alternative to plant protection products from the chemical industry. It has strong potential in the field of combating biotic stress where it constitutes an effective treatment against certain diseases. It has two modes of action that come on the one hand from its bacterio- and fungistatic properties (antimicrobial activity) and on the other hand from its ability to induce the natural defenses of plants (SDP). Indeed, thanks to its cationic character, chitosan polymers will interact with the cell membranes of negatively charged pathogens which will alter membrane permeability. Through an elicitor mechanism, chitosan will also stimulate the natural defenses of plants in response to a broad spectrum of phytopathogens. Used alone, chitosan generally does not achieve a level of protection equivalent to a synthetic fungicide reference.

Chitosan is authorised for marketing in Europe, in particular as chitosan hydrochloride, for the protection of various plants against fungal or bacterial infections. Chitosan of fungal origin is also authorised. Chitosan acetate (obtained with acetic acid rather than hydrochloric acid) may also be considered.

Examples include protection against fungal infections of olive trees, vines (Vitis vinifera), lawns, meadows, ryegrass, sugar beets, cereals, potatoes, vegetables, berries and small fruits (blackcurrants, strawberries, raspberries, blueberries, etc.), and bulbous ornamental plants.

Table 1 provides a list of plants and bacterial or fungal pathogens that may be treated with phosphonates or chitosan.

*perfume, food, medicinal and condiment plants

Table 1. Based on Andrivon et al, Can we do without copper in the protection of organic crops? Collective scientific expertise report. INRA-DEPE June 2018

As seen above, phosphonates (potassium phosphonate or disodium phosphonate) are approved against a large number of fungal diseases and bacterial diseases, for perennial crops (vines, fruit crops), market gardens (crops belonging to various botanical families), large-scale crops (control of potato blight, and against some fungal diseases of wheat and rye (in particular septoria due to Steptoria sp. In particular Septoria tritici or Septoria nodorum). Phosphonates can also be used against various fungal diseases affecting perfume, aromatic and medicinal plants (PPAM), ornamental species and seed crops, or which develop on wood wounds.

Chitosan can also be used against a large number of fungal diseases and bacterial diseases, for perennial crops (vines, fruit crops), market gardens (crops belonging to various botanical families), large-scale crops (fight against potato blight, and against some fungal diseases of wheat and rye (notably fusarium) transmitted by seeds.

Among these diseases, we can particularly emphasize downy mildew of the vine, caused by Plasmopara viticola, which is one of the two main diseases (with powdery mildew) of this crop. The fight against mildew requires numerous applications (up to fifteen per year).

Another example is apple scab, caused by Venturia inaequalis, for which apple orchards receive an average of 23 fungicide/bactericide treatments per year (15 to 29 depending on the region), of which nearly three-quarters target scab. Phosphonate-based treatments could also control Nectria galligena, which causes European canker.

Potato blight caused by Phytophthora infestans causes yield losses that can lead to total destruction of the plot, or quality losses in the event of late attacks. On average, 10 to 12 treatments are carried out, or up to 15 or 20 in areas at high risk of blight. P. infestans can also cause significant damage to tomatoes (also from the Solanaceae family).

Beet leaf spot is a leaf disease caused by Cercospora beticola, which can cause significant damage if attacks occur early or in irrigated areas.

Black spot disease is caused by Alternaria brassicicola on a wide range of hosts, particularly in the genus Brassica, including a number of economically important crops such as cabbage, Chinese cabbage, cauliflower, oilseeds, broccoli and canola.

Lettuce downy mildew is caused by Bremia lactucae and can cause death of young seedlings.

Septoria leaf spot of wheat is a fungal disease caused mainly by Septoria tritici and Septoria nodorum, which affects wheat and other species of the genus Triticum. It can cause yield losses of more than 40%.

Alternaria solani can cause a disease called alternaria leaf spot or alternaria blight in plants of the Solanaceae family, including tomatoes and potatoes, but also peppers and eggplants, which manifests itself as circular black spots, in which concentric circles are visible, on the leaves of the plants, and can lead to defoliation.

It therefore appears necessary to continue using phosphonates, while controlling the quantity of use, in order to avoid an accumulation of this product in the soil. It is also necessary to improve the effect of chitosan, in order to combat bacterial and/or fungal diseases, while controlling its amount of use, especially to reduce costs.

The invention relates to a method for treating a plant, comprising the simultaneous, staggered or separate application in time of (I) y-mangostin and (II) a phytosanitary product chosen from (i) phosphonates, in particular potassium phosphonates, and (ii) chitosan. It is preferred when compounds (I) and (II) are applied to obtain a synergistic effect (thus making it possible to obtain an effect greater than the sum of the individual effects). The desired effect is in particular a fertilizing effect to improve plant growth or leaf growth, or an antifungal or antibacterial effect to combat bacteriosis or fungal diseases. In particular, y-mangostin can be provided via a Garcinia mangostana extract containing y-mangostin, in particular between 2 and 15% (by weight) of y-mangostin. This extract may result from the maceration of pericarps of G. mangostana in a polar solvent, preferably in ethanol. It is preferred that y-mangostin and compound (II) are applied simultaneously.

γ-Mangostin and compound (II) may be applied to prevent or control bacterial or fungal diseases, or as a fertilizing agent to improve plant growth or leaf growth. Compound (II) may be phosphonates, in particular potassium phosphonates. Compound (II) may be chitosan, in particular chitosan hydrochloride. γ-Mangostin is preferably applied at a rate of between 1 and 40 g/ha, preferably between 1 and 8 g/ha, phosphonates are preferably applied at a quantity of between 250 and 4000 g/ha and chitosan is preferably applied at a quantity of between 250 and 4000 g/ha. A composition comprising (I) y-mangostin and (II) a phytosanitary product selected from (i) phosphonates, in particular potassium phosphonates, and (ii) chitosan, compounds (I) and (II) preferably in doses and a ratio making it possible to obtain a synergistic effect, the use of such a composition as a fertilizing composition, or a phytosanitary composition, and/or for improving the growth and/or development and/or productivity of plants and/or defense against plant pathogens are also described. In particular, the invention relates to a method for treating plants, in which phosphonates, in particular potassium phosphonates, and y-mangostin, in particular contained in an extract of Garcinia mangostana, are combined. The treatment applied to the plants may have a phytosanitary and/or growth-stimulating effect. It may also be used as a fertilizer, fertilizer or biostimulant. The two compounds are advantageously added in conditions and proportions making it possible to obtain a synergistic effect (the examples and the information in the application allow a person skilled in the art to determine the doses making it possible to observe a synergy).

The invention also relates to a phytosanitary composition comprising phosphonates (ll)(i), in particular potassium, and y-mangostin (I), in particular contained in an extract of Garcinia mangostana, in particular when the extract contains y-mangostin. This composition contains the compounds (ll)(i) and (I) in proportions and amounts making it possible to obtain a synergistic effect during application.

More particularly, this method and the relative compositions make it possible to improve the effectiveness of phytosanitary products based on phosphonates, by reducing the doses of phosphonates, while maintaining the effect of preventing the appearance or treatment of fungal diseases of plants, for example downy mildew of grapevines, alternaria of cruciferous plants, downy mildew of lettuce or even septoria of wheat.

Thus, reduced doses of phosphonates are applied in combination with y-mangostin, which potentiates the effect of phosphonates, via a synergistic effect. Thus, plant diseases can be effectively combated while drastically reducing the quantities of phosphonates applied compared to current practices.

The invention also relates to a method for treating plants, in which chitosan (ll)(ii), in particular chitosan hydrochloride and y-mangostin, in particular contained in an extract of Garcinia mangostana, are combined. The treatment applied to the plants can have a phytosanitary and/or growth-stimulating effect. It can also be used as a fertilizer.

The invention also relates to a phytosanitary composition comprising chitosan (ll)(ii), in particular chitosan hydrochloride, and y-mangostin (I), in particular contained in an extract of Garcinia mangostana. This composition contains compounds (ll)(ii) and (I) in proportions and quantities enabling a synergistic effect to be obtained upon application.

More particularly, this method and the relative compositions make it possible to improve the effectiveness of chitosan-based phytosanitary products, by potentially reducing the doses of chitosan, while maintaining the effect of preventing the appearance or treating fungal diseases of plants, for example downy mildew of grapevines, alternaria of cruciferous plants or even downy mildew of lettuce.

Thus, reduced doses of chitosan can be applied in combination with y-mangostin, which can potentiate the effect of chitosan, via a synergistic effect. Thus, plant diseases can be effectively combated while drastically reducing the quantities of chitosan applied compared to current practices.

WO 2023/099609 describes a method for preventing, controlling or treating a fungal infection on a plant organ comprising applying to said plant organ a non-fungicidal amount or a potentiating amount of a composition comprising a potentiating agent of a plant defense molecule, in combination with a phytopharmaceutical vehicle. The molecules described in this document include molecules of general formula (I).

Gopalakrishnan et al (J Nat Prod. 1997 May;60(5):519-24) described the isolation of several xanthones from G. mangostana, including y-mangostin (compound 5), and the analysis of their antifungal effect. Tables 3-5 show that y-mangostin is the most potent compound.

Adamu et al (Materials & Design 209 (2021): 109942), Samprasit et al (Carbohydr Polym. 2015 Mar 6:117:933-940) and Charernsriwilaimat et al (Int J Pharm. 2013 Aug 16;452(1-2):333-43) describe nanofibers based on chitosan and chitosan pericarp extract.

Azman et al (Food Control, (2022) 141, 109189) describe films containing chitosan and mangosteen extracts.

The invention thus relates to a method of treating a plant, comprising the simultaneous, staggered or separate application in time of (I) y-mangostin and (II) a phytosanitary product chosen from (i) phosphonates, in particular potassium phosphonates, and (ii) chitosan, compounds (I) and (II) being applied to obtain a synergistic effect

Gamma mangostin (y-mangostin) has the formula (I).

It is recalled that alpha-mangostin has the same R1-R6 and R8 groups as gamma-mangostin, but an -O-CH3 group in position R7.

This molecule is present in the mangosteen shell (Garcinia mangostana). We can thus use an extract of Garcinia mangostana to bring this molecule into the composition to be applied to plants, with phosphonates.

In a preferred embodiment, the G. mangostana extract contains y-mangostin and a-mangostin. In some embodiments, the ratio of Y-mangostin to a-mangostin is between 1:4 and 1:9, or between 1:6 and 1:8.

Typically, an extract of Garcinia mangostana is used, preferably selected from the leaf, bark or pericarp extract of Garcinia mangostana. Generally, the extract is a pericarp extract of Garcinia mangostana.

In one embodiment, this extract is an aqueous extract, a hydroalcoholic extract, an ethanolic extract, a methanolic extract, an ethyl acetate extract or a supercritical CO2 extract. These extracts can in particular be obtained by maceration of pericarps of Garcinia mangostana in a solvent (in particular a polar solvent), as described. In one embodiment, the extract is obtained with a mixture of ethyl acetate and ethanol, typically in a volumetric ratio of ethyl acetate:ethanol ranging from 60:40 to 90:10, from 70:30 to 80:20, from 75:25 to 80:20. In a specific embodiment, the extract is obtained with a mixture of ethyl acetate and ethanol, in an ethyl acetate:ethanol volumetric ratio of about 75:25, about 76:24, about 77:23, about 78:22, about 79:21, or about 80:20. In In one embodiment, ethanol is used only as a solvent. In one embodiment, the maceration is carried out using water and ethanol as solvents. In one embodiment, the maceration is carried out using supercritical CO2 and ethanol as solvents.

In one embodiment, the plant:solvent ratio is between 1:2 and 1:10 (% weight/weight), preferably between 1:4 and 1:6.

Extracts can be obtained by ultrasound or microwave-assisted extraction methods.

A crude extract of the plant or a fractionated portion thereof may be used, including using any method known in the art such as chromatography, to fractionate a crude extract, such as liquid-liquid extraction/fractionation and/or adsorption/absorption chromatography.

The fractionated portions of the crude extract may comprise y-mangostin at different concentrations. The crude extract of Garcinia mangostana pericarp may further comprise other xanthones, such as 1,3,5-trihydroxy-4-prenylxanthone, 1,3,5-trihydroxy-2-prenylxanthone. The crude extract of Garcinia mangostana pericarp may further comprise xanthones, such as α-mangostin. Advantageously, the crude extract of Garcinia mangostana pericarp may be used at a concentration where all of its constituents are in an in vitro amount that is not directly fungicidal, such as less than 200 mg/L, less than 150 mg/L or less than 100 mg/mL. Compositions containing up to 1 g/L can also be used (used to provide a dose of approximately 200 g/Ha, or a volume of 200 L/Ha).

A final extract of Garcinia mangostana comprising from 3 to 12%, or from 3 to 10% w/w of y-mangostin on a dry weight basis relative to the dry weight of the final extract can be obtained. For example, 100 mg of final extract of G. mangostana comprises about 6 mg of y-mangostin. The extract of G. mangostana may also contain alpha-mangostin.

A person skilled in the art will be able to adapt these non-fungicidal quantities if a fraction rich in y-mangostin or poor in y-mangostin is used instead of the crude extract of Garcinia mangostana pericarp, in particular obtained by extraction with a polar solvent. The method according to the invention makes it possible to reduce the quantities of phosphonates or chitosan used to combat pathogens.

Thus, due to the existence of a synergy between phosphonates and y-mangostin, or chitosan and y-mangostin, as shown in the examples, the dose of phosphonates or chitosan can be reduced, i.e. a lower dose can be used (generally divided by at least 2) compared to the dose used in practice or that which allows a maximum effect to be obtained when phosphonates or chitosan are used alone. By reducing the dose, doses can thus be used which do not a priori allow the pathogen to be combated in vivo or the growth of the pathogen to be prevented in vitro. If the doses are not reduced, the effect obtained will be better than when phosphonates or chitosan are used alone.

Reducing the quantities of phosphonates or chitosan applied thus makes it possible to avoid the occurrence of undesirable effects, while maintaining the same level of protection. In addition, the combination of two molecules with different modes of action generally makes it possible to limit the development of resistance in the targeted pathogenic microorganisms. The application of antifungal agents at low doses makes it possible to reduce their potential undesirable effects on fauna and flora and to reduce their residues.

In practice, the quantity of phosphonates or chitosan applied per hectare depends essentially on the type of plants to be protected, rainfall, and pest pressure.

Due to the presence of molecules of formula (I), it is possible to reduce the quantity of phosphonates or chitosan to be applied per hectare at each treatment.

Thus, it is possible to consider reducing the annual dose of phosphonates or chitosan, if the same number of applications is maintained, or to increase the number of applications and/or the frequency between two applications, by implementing the method according to the invention, due to the reduction in the dose per application.

In one embodiment, the phosphonates and y-mangostin, particularly in an extract of G. mangostana are applied simultaneously. In particular, a composition comprising both the phosphonates and y-mangostin is prepared. In another embodiment, the phosphonates and y-mangostin are administered simultaneously or successively, by application to the plants (in particular spraying, spreading, watering) or any other means making it possible to provide the phosphonates and y-mangostin to the infected or susceptible place (site). It is possible to start by applying the phosphonates then the y-mangostin, or to provide first the y-mangostin then the phosphonates.

According to one embodiment, the phosphonates and γ-mangostin are mixed in the same container or placed in two separate containers.

Phosphonates are generally applied at a rate of between 250 and 4000 g/ha (grams per hectare), preferably between 500 and 1000 g/ha, preferably between 600 and 900 g/ha, preferably between 700 and 800 g/ha. Due to the synergy, it is also possible to consider reducing the doses applied.

In a preferred embodiment, the phosphonates are potassium phosphonates. In another embodiment, the phosphonates are disodium phosphonates.

In one embodiment, chitosan and y-mangostin, particularly in an extract of G. mangostana are applied simultaneously. In particular, a composition comprising both chitosan and y-mangostin is prepared.

In another embodiment, the chitosan and γ-mangostin are administered simultaneously or successively, by application to the plants (in particular spraying, spreading, watering) or any other means making it possible to provide the chitosan and γ-mangostin to the infected or susceptible place (site). It is possible to start by applying the chitosan then the γ-mangostin, or to provide first the γ-mangostin then the chitosan.

According to one embodiment, the chitosan and the γ-mangostin are mixed in the same container or placed in two separate containers.

According to one embodiment of the invention, the amount of chitosan applied per hectare is between 10 and 1000 g/ha, preferably between 20 and 90 g/ha, preferentially between 30 and 80 g/ha, more preferentially between 40 and 160 g/ha per administration. However, higher doses can be applied depending on the nature and quality of the chitosan. Due to the synergy, it is also possible to consider reducing the doses applied.

In crop protection, chitosan is usually found in the form of chitosan hydrochloride. Nowadays, chitosan of the original type is also available. fungal. Chitosan acetate salt can also be made with acetic acid.

In one embodiment, the amount of y-mangostin supplied per hectare according to the invention is between 1 and 40 g/ha, preferably between 1 and 15 g/ha, preferentially between 1.5 and 10 g/ha, more preferentially between 4 and 8 g per hectare.

According to one embodiment, the composition is in liquid form. It is administered by spraying or watering. In another embodiment, the composition is in a form allowing the coating or film-coating of seeds: this is particularly suitable for the control or prevention of root fusarium diseases affecting cereals.

In one embodiment, phosphonates, in particular potassium or chitosan, and y-mangostin, in particular as an extract of G. mangostana, are applied to prevent or combat bacterial diseases or fungal diseases. In particular, these elements can be used to prevent or combat the diseases mentioned in Table 1, for the plants considered. However, emphasis can be placed on the prevention or control of apple scab (Venturia inaequalis), mildew in particular of vines, lettuce or potatoes, Botrytis infections in particular on vines and tomatoes, Fusarium infections in particular on cereals (wheat and barley), cereal septoria, Septoria sp. infections in particular wheat septoria, cruciferous or solanaceae alternaria or beet leaf spot (Cercospora beticolà). Of particular note are lettuce downy mildew, potato downy mildew, cabbage leaf blight and wheat leaf blight. Both compounds are particularly interesting against Altenaria solani, Venturia inaequalis or Alternaria brassicicola, or the pathogens responsible for the other diseases cited in this application.

Phosphonates and chitosan can also be used in fertilizers. Indeed, they help to strengthen the vigor of plants, as elicitors of natural defenses. Thus, phosphonates or chitosan and y-mangostin can be used as fertilizers or fertilizing agents to improve plant growth or foliar growth. In this mode of use, we also preferentially provide other compounds (trace elements such as manganese, zinc, iron, boron, silicon, even molybdenum, etc.) which are also useful, even essential for plant growth.

The invention also relates to a composition for application to plants comprising phosphonates, in particular potassium phosphonates, and y-mangostin, in particular as an extract of G. mangostana. The invention also relates to a composition for application to plants comprising chitosan, in particular chitosan hydrochloride, and y-mangostin, in particular as an extract of G. mangostana.

These compositions can be used as a fertilizing agent, or a phytosanitary agent, in particular depending on the concentrations of the two elements that are present. They therefore have advantages for the growth and/or nutrition and/or health of plants.

It is understood that the concentrations of each of the compounds are determined by the person skilled in the art, and can be increased or decreased, depending on the quantity of composition that one wishes to apply per hectare, and the dilution of the “mother” composition before application. Thus, depending on the nature of the plant to be treated, the pathogen envisaged (and the strength of the attack of this pathogen) or the use as a fertilizing agent, the quantities can be low, or high.

Phosphonates or chitosan are advantageously mixed with an extract of G. mangostana, as seen above, which provides y-mangostin.

A "mother" composition is generally made to be diluted (generally 1:100 or 0.5:100 (v:v)) before application to plants. The quantities applied are preferably those mentioned above. The composition is generally applied after appropriate dilution, to the leaves or fruits of the plant (foliar or fruit application), by spraying. However, the composition can be applied after appropriate dilution, at the base of the plant.

It can be in the form of a suspension, emulsion or dispersion in a preferably aqueous phase, but also in the form of a powder or granules or tablets. In these latter embodiments, water is added before administration, to obtain the adequate quantities of phosphonates or chitosan and y-mangostin. The composition may also contain trace elements (zinc, boron, manganese, silicon, iron, etc.) to provide the elements useful for plant growth and have a fertilizing effect. It also preferably contains co-formulants (chosen in particular from texturizing agents, wetting agents, surfactants, suspenders, emulsifiers, preservatives, etc.) adapted according to the intended application (administration by spraying on the leaves, at the base of the plant, in the watering water, etc.).

The invention also relates to a method for manufacturing a composition as described comprising the simultaneous or successive incorporation of at least phosphonates, in particular potassium phosphonates, or chitosan, in particular chitosan hydrochloride and γ-mangostin with co-formulating agents. These elements can then be mixed to obtain a suspension, an emulsion or a dispersion in a preferably aqueous phase.

It is recalled that co-formulating agents include surfactants (surfactants), to reduce the surface tension between liquids and surfaces and improve the dispersion and adhesion of active agents (in particular alkylphenol ethoxylates, polysorbates), adjuvants that increase the penetration of active agents into plants (mineral oils, vegetable oils, wetting agents), suspending agents to maintain solid particles in suspension in liquid formulations (bentonite, colloidal silica), stabilizers to prevent decomposition of active agents by environmental factors such as light, heat or oxygen (antioxidants, UV absorbers), solvents allowing the dissolution of active agents to create a homogeneous formulation and facilitate application (organic solvents such as xylene, acetone, ethanol), sequestration agents to bind metal ions that could otherwise inactivate the active agents (EDTA (ethylenediaminetetraacetic acid), citric acid), polymers or gelling agents, penetrating agents (alcohol ethoxylates, sulfosuccinates), buffers and pH agents (citric acid, phosphates), or dispersing agents.

The invention also relates to the use of the composition as described for improving the growth and/or development and/or productivity of plants. The invention also relates to the use of the composition as as described to control or prevent a plant infection, particularly a bacterial or fungal infection.

The invention also relates to the composition as described, or to its use, as a fertilizer product (for improving the growth and/or development and productivity of plants). The invention also relates to the composition as described, or to its use, as a phytosanitary product (for its antifungal effect for combating or preventing a plant infection, in particular a bacterial or fungal infection).

EXAMPLES

Example 1. Definition of indicators

Efficacy: Indicator for quantifying the effect of a plant protection product on reducing damage (severity or incidence) caused by a plant disease. This is calculated using the Abbott formula presented below:

Synergy: Corresponds to the interaction between at least two products whose combined effects are greater than the sum of their own effects (effect of the type “one plus one is greater than two”).

R ratio: Indicator used to describe the relationship between two plant protection products with regard to the effectiveness obtained by their combined application. This relationship can be of three types:

- Antagonistic: the efficacy obtained by co-application is lower than the sum of the efficacies of the two products applied alone (type 1+1 < 2);

- Additive: the efficiency obtained by co-application is identical to the sum of the efficacies of the two products applied alone (type 1+1 = 2);

Synergistic: the efficacy obtained by co-application is greater than the sum of the efficacies of the two products applied alone (type 1+1 > 2).

The R ratio is calculated by dividing the observed efficiency (E _O bs) by the combination of products by the theoretical efficiency (E^éo):

_D > _o bs ~ c F - t/iéo The theoretical efficiency is calculated according to the Colby formula presented below, where X and Y are the observed efficiencies for the two products applied alone.

Thus, if the ratio R is less than 1, the relationship between the two products is antagonistic, when it is equal to 1, the products are additive and when it is greater than 1, the relationship is synergistic. Therefore, the ratio R is a tool for assessing the level of synergy between two products, with synergy being all the more important as R is large.

Example 2. Obtaining an extract of G. mangostana

One hundred grams (100g) of dried and ground pericarps of Garcinia mangostana were extracted twice by ethanol maceration with a weight-volume ratio of 1:4, which gave 10 g of dry crude extract of G. mangostana. The average extraction yield was therefore 10% w/w, i.e. 100 g of crude extract produced per 1000 g of dried and ground pericarps of Garcinia mangostana. Thin-layer chromatography analysis of the crude extract indicated the presence of y-mangostin, which was confirmed by NMR spectrometry.

Analysis of a 100 mg/L solution of the crude extract of Garcinia mangostana pericarp showed an amount of 5.9 mg/L of y-mangostin in this extract.

In another method, the crushed Garcinia mangostana pericarps are extracted twice with ethanol as solvent, with a plant/solvent ratio ranging from 1:4 to 1:8 (% w/w) for each extraction, at room temperature. The average extraction yield is between 6 and 15%, i.e. between 6 and 15 g of Garcinia mangostana pericarp extract are obtained using 100 g of Garcinia mangostana pericarps as raw material. The extract obtained is composed of y-mangostin in a proportion ranging from 3 to 12% (% w/w), and a-mangostin in a proportion ranging from 20 to 50% (% w/w).

In another process, crushed Garcinia mangostana pericarps are extracted with supercritical CO2 as solvent and ethanol as co-solvent (30%), under suitable conditions of temperature, pressure and flow rate of the solvent and co-solvent. The average extraction yield is between 6 and 15%, i.e. between 6 and 15 g of Garcinia mangostana pericarp extract are obtained using 100 g of Garcinia mangostana pericarp as raw material. The extract obtained is composed of y-mangostin in a proportion ranging from 3 to 12% (% w/w), and a-mangostin in a proportion ranging from 20 to 50% (% w/w).

In another method, the crushed Garcinia mangostana pericarps are extracted with a water:ethanol mixture (70:30 by volume) as solvent, with a plant/solvent ratio ranging from 1:4 to 1:16 (% w/w) for each extraction, at room temperature. The average extraction yield is between 6 and 15%, i.e. between 6 and 15 g of Garcinia mangostana pericarp extract are obtained using 100 g of Garcinia mangostana pericarps as raw material. The extract obtained is composed of y-mangostin in a proportion ranging from 3 to 12% (% w/w), and a-mangostin in a proportion ranging from 20 to 50% (% w/w).

These methods, using ethanol as a solvent in particular, therefore give equivalent results and extracts, with regard to the quantity of y-mangostin.

Example 3. Synergy between an extract of Garcinia mangostana (MCE or GME) and potassium phosphonates - in planta tests on wheat septoria (Septoria tritici).

Potassium phosphonates were used at a dose of 151 mg/L, alone and in combination with GME at 247.5 mg/L.

The results are presented in Table 2.

Table 2. In planta trials on wheat septoria. This test shows that the combination of G. mangostana extract and phosphonates improves the performance of each product. A synergy was observed.

Other trials (GME 200 pM + PYGMALION® (De Sangosse, France) 0.5% or 1%) showed a synergy ratio between 1.1 and 1.6.

Example 4. Synergy between G. mangostana extract and potassium phosphonates - in planta trials on potato late blight (Phytophthora infestans)

Potassium phosphonates were used at a dose of 151 mg/L, alone and in combination with GME at 247.5 mg/L.

The results are presented in Table 3.

Table 3: In planta potato blight trials.

A synergy is observed in in planta conditions with a significant gain in protection compared to products used alone.

Example 5. Synergy between G. mangostana extract (GME) and potassium phosphonates - in planta trials on Bremia lactucae (lettuce downy mildew)

Using GME (1900 mg/L) and PYGMALION® (phosphonates) at 1%, a synergy ratio between 1.8 and 2.3 was observed.

Example 6. Synergy between a G. mangostana extract (GME) and potassium phosphonates - in vitro tests on Plasmopara viticola (vine mildew) Using GME (1.5 and 2 mg/L) and LBG 01 F34 (potassium phosphonates, De Sangosse, France) at 0.0015% and 0.003%, a synergy ratio between 1.3 and 2.0 was observed.

Example 1. Synergy between an extract of Garcinia mangostana and chitosan hydrochloride - in vitro tests on Alternaria brassicicola (alternaria of cabbage),

Doses of 200 mg/L of chitosan hydrochloride, alone and in combination with GME at 247.5 mg/L, were used using nephelometry to study their inhibitory effect on the growth of Alternaria brassicicola, a pathogen responsible for cabbage early blight.

For this, each dose alone and in combination was applied to a suspension of Alternaria brassicicola for a period of 4 hours. After 4 hours, the suspension is diluted in cascade until reaching a concentration of 1*10 ³ conidia per mL of PDB (Potato Dextrose Broth). The different modalities are then distributed in a 96-well plate placed in a nephelometer at 25°C for 338 cycles of 600 s, or a total of approximately 56 hours, to monitor the growth of the pathogen subjected to the different conditions. The data are then analyzed using Omega data analysis software to obtain areas under the curve and calculate inhibition percentages presented in Table 4.

This test shows that the combination of G. mangostana extract and chitosan hydrochloride improves the performance of each product. A synergy was observed. Beyond obtaining a simple synergy ratio, an improvement in performance in terms of inhibition of the growth of the pathogen is also observed compared to a simple additive effect between GME and chitosan. Example 8. Synergy between G. manqostana extract and chitosan hydrochloride - in planta trials on wheat septoria

An in planta study was carried out to investigate the compatibility, and a potential synergy, between GME and chitosan hydrochloride in the control of wheat septoria.

Chitosan hydrochloride was applied at 200 mg/L.

GME is used at 247.5 mg/L.

A synergy is thus observed in in planta conditions with a significant gain in protection compared to products used alone, including chitosan at a reduced dose.

Example 9. Synergy between G. mangostana extract (GME) and chitosan hydrochloride - in vitro tests on Bremia lactucae (lettuce downy mildew)

The following results are obtained (dose of 247.5 mg/L for GME, 200 mg/L for chitosan)

Table 6: Tests on Bremia lactucae in planta.

Other in planta tests (GME 1900 mg/L, chitosan hydrochloride 0.05%) showed a synergy ratio of the order of 2.5. The combination of chitosan hydrochloride and GME shows very good in planta performance against lettuce downy mildew.

Example 10. Synergy between a G. mangostana extract (GME) and potassium phosphonates - in vitro tests on Plasmopara viticola (vine mildew)

Using GME (1.5 and 2 mg/L) and chitosan hydrochloride (11.5% solution) at 0.0002% and 0.0004%, a synergism ratio between 1.2 and 1.3 was observed.

Example 11. Conclusion

The above trials show an effect of the combined use of an extract of G. mangostana (containing y-mangostin) and phosphonates on various pathogens, according to different in planta protocols. These trials have demonstrated a synergistic effect between GME and potassium phosphonates. The above trials also show an effect of the combined use of an extract of G. mangostana (containing y-mangostin) and chitosan on various pathogens, according to different in planta, in vitro protocols. These trials have demonstrated a synergistic effect between GME and chitosan.

Thus, surprisingly, the addition of GME to a product based on phosphonates or chitosan makes it possible to increase its effectiveness (synergistic effect) and thus possibly reduce the doses applied.

Claims

1. Method of treating a plant, comprising the simultaneous, staggered or separate application in time of (I) y-mangostin and (II) a phytosanitary product chosen from (i) phosphonates, in particular potassium phosphonates, and (ii) chitosan, compounds (I) and (II) being applied to obtain a synergistic effect. 2. A method according to claim 1, wherein the y-mangostin is provided via a Garcinia mangostana extract containing y-mangostin. 3. A method according to claim 2, wherein the G. mangostana extract contains between 2 and 15% (by weight) of y-mangostin. 4. Method according to claim 2 or 3, in which the extract of G. mangostana has been obtained by maceration of pericarps of G. mangostana in a polar solvent, preferably in ethanol. 5. Method according to one of claims 1 to 4, in which the y-mangostin and the compound (II) are applied simultaneously. 6. Method according to one of claims 1 to 5, in which the y-mangostin and the compound (II) are applied to prevent or combat bacteriosis or fungal diseases. 7. Method according to claim 6, wherein y-mangostin and compound (II) are applied to prevent or control apple scab caused by Venturia inaequalis, downy mildew in particular of grapevine, lettuce or potato, Botrytis infections in particular on grapevine and tomato, Fusarium infections in particular on cereals (wheat and barley), Septoria sp. infections in particular septoria leaf spot of wheat, alternaria leaf spot of cruciferous plants and solanaceae or cercospora leaf spot of beet caused by Cercosporia beticola. 8. A method according to any one of claims 1 to 5, wherein the y-mangostin and compound (II) are applied as a fertilizing agent to improve plant growth or leaf growth. 9. Method according to one of claims 1 to 8, in which the compound (II) consists of phosphonates, in particular potassium phosphonates. 10. Method according to one of claims 1 to 8, in which the compound (II) is chitosan. 11. Method according to claim 9, wherein the y-mangostin is applied at a dose of between 1 and 40 g/ha, preferably between 1 and 8 g/ha, and the phosphonates are applied at an amount of between 250 and 4000 g/ha. 12. Method according to claim 10, wherein the y-mangostin is applied at a dose of between 1 and 40 g/ha, preferably between 1 and 8 g/ha, and the chitosan is applied at an amount of between 10 and 1000 g/ha. 13. Composition for application to plants comprising (I) y-mangostin and (II) a phytosanitary product chosen from (i) phosphonates, in particular potassium phosphonates, and (ii) chitosan. 14. Use of a composition according to claim 13 as a fertilizing composition, or a phytosanitary composition. 15. Use of a composition according to claim 13, for improving the growth and/or development and/or productivity of plants and/or defense against plant pathogens.