Niobium-based nano-fungicidal compositions, process and uses

Abstract

The present invention concerns technology relating to nano-fungicidal compositions based on niobium and commercial fungicides. Such compositions are composed of a combination of polyoxonium niobate nanoparticles and selected fungicidal products from the group of compounds containing triazoles, dithiocarbamates, strobilurins and carboxamides. This combination is achieved by mixing the two components together directly. The product resulting from the combination of polyoxonium niobate nanoparticles and a fungicide comprising trifloxystrobin and cyproconazole was applied to plants, demonstrating synergistic effects through the high percentage of inhibition observed three days after application.

Description

[0001] "Niobium-based nanofungicidal compositions, process and uses"

[0002]

[0001] The present technology deals with niobium-based nanofungicidal compositions and commercial fungicides. These compositions are formed by the association between polyoxoniobate nanoparticles and selected fungicidal products from the group of compounds containing triazoles, dithiocarbamates, strobilurins, and carboxamides. This association occurs through the direct mixing of both components. The product resulting from the association between polyoxoniobate nanoparticles and a fungicide composed of trifloxystrobin and cyproconazole was applied to plants, demonstrating synergism through the high percentage of inhibition after three days of application.

[0003]

[0002] Fungal infections are responsible for approximately 70 to 80% of agricultural production losses caused by microbial diseases. Around 8,000 different species of fungi were known to cause approximately 100,000 different plant diseases. In recent years, the number of fungi known to cause plant diseases worldwide has increased to over 19,000. Fungal diseases are a growing concern worldwide, with a serious impact on public health. Food insecurity and malnutrition are major problems in both developing and industrialized countries. Due to poor management strategies, developing countries experience 20 to 25% of total crop production losses associated with fungal diseases. Under unfavorable environmental conditions, this yield loss can increase to 50% or more.

[0004]

[0003] Fungal diseases are increasingly recognized as a global threat to food security and biodiversity. This is due to the fact that fungi are highly resistant microorganisms that destroy crops, forests, and animal species. Although this problem is not new, fungal diseases represent a widespread threat to different plant species, especially wheat, corn, rice, potatoes, and soybeans. It is estimated that at least 125 million tons of food are destroyed by fungal diseases each year.

[0005]

[0004] Fungal diseases are controlled using synthetic fungicides in agriculture. Although several fungicides are potential solutions against foliar pathogens, these products may not be ideal long-term solutions due to their high cost and impacts on the environment and human health. Furthermore, the evolution of phytopathogen resistance is considered a major problem in agriculture, making the development of new, safe, effective, and environmentally friendly pest control and management agents urgent. In addition to the development of new fungicidal molecules, the demands for more environmentally conscious agriculture require that they be low in toxicity and contribute, alone or in combination with commercial products, to more sustainable and efficient agriculture.

[0006]

[0005] The harmful effects of chemical fungicides used in the production of various crops have led to the search for new antimicrobial agents based mainly on nanomaterials as efficient alternatives in the control of fungal diseases, promoting less interference in the environment and with fewer risks to human health. The state of the art indicates that the use of nanoparticles represents a new and promising approach to control fungal infections in plants (ABBAS, M. et al. Frontiers in Bioengineering and Biotechnology. 10, 853045, 2022. DOI: 10.3389 / fbioe.2022.853045), in addition to improving the ability of plants to absorb nutrients (ROSA-GARCÍA, SC et al. Journal of Nanomaterials. 2018, 3498527, 2018. DOI: 10.1155 / 2018 / 3498527).

[0006] The combination of metallic nanoparticles with a variety of compounds, generating antifungal compositions, is known in the state of the art, as demonstrated in patent document CA2640426, entitled “Combinations of imazalil and silver compounds?”, whose priority date is 06 / 03 / 2007 and publication date is 13 / 09 / 2007. This document describes the association of imazalil (also called enilconazole or chloramizole) with silver compounds, generating a synergism that improved the control of microbial growth in plants, seeds and fruits.

[0007]

[0007] Research conducted by El-Abeid et al. (EL-ABEID, SE et al. Journal of Nanobiotechnology. 22, 2024. DOI: 10.1186 / s 12951-023- 02281-8) demonstrated that the association between copper oxide (CuO) nanoparticles and Zizyphus spina leaf extract is an efficient alternative as an antifungal, as shown by in vitro and in vivo tests against strains of the fungus F. solani.

[0008]

[0008] Patent document WO2013071824, entitled “A method for treating fungal infections, fungicidal compositions and their use”, with a priority date of 02 / 11 / 2012 and a publication date of 23 / 05 / 2013, discloses the combination of triazole fungicides with micronutrients (including salts of transition metal cations) to solve the technical problem of reducing the phytotoxicity of the triazoles used. The document describes the use of common salts such as sulfate and metal chlorides, without describing the use of metal complexes.

[0009]

[0009] Specifically, the effect of niobium nanoparticles and polyoxoniobates as fungicides and foliar markers is known (FIGUEIREDO, AO; FIGUEIREDO, GA Annals of Bioethics & Clinical Applications. 4, 2021. DOI: 10.23880 / abca-16000209), as described in patent document BR102020016362, entitled “Nanostructured hybrid material based on niobium oligomers, process of obtaining and use”, whose priority date is 11 / 08 / 2020. This document reveals the association of niobium nanoparticles (negatively charged niobium oligomers) with quaternary ammonium salts, methylene blue, gentian violet and / or fuchsin.

[0010]

[0010] Patent document BR132021019928, entitled “Nanostructured hybrid material based on niobium oligomers, process for obtaining it and its use as a fungicide and biomarker 1' , whose priority date is 04 / 10 / 2021 and publication date is 06 / 12 / 2022, expands on the contents disclosed in BR102020016362 in order to incorporate copper salts as possible additives to polyoxoniobates.

[0011]

[0011] The study conducted by Kumar et al (KUMAR, R. et al. Rasayan Journal of Chemistry. 6, 183-189, 2013) shows the complexation of niobium isopropoxides with Schiff bases derived from semicarbazides and thiosemicarbazides with known antifungal activity, revealing an increase in the activity of the resulting compound.

[0012]

[0012] However, there are no reports of the combination of polyoxoniobate nanoparticles with organic fungicidal compounds that occur through intermolecular association for crop protection in agriculture, nor are there any demonstrations of the resulting synergistic effect in the state of the art.

[0013]

[0013] It is of significant interest to investigate the combined effect of this combination to increase antimicrobial activity, reduce pesticide load, and delay the development of fungal resistance. Therefore, the present invention establishes a “green” nanotechnology that controls pathogenic microorganisms and has synergistic antimicrobial activity with commercial products to protect crops efficiently and in an environmentally friendly manner.

[0014]

[0014] In addition to high fungicidal activity, it is noteworthy that the combination of commercial compounds with polyoxoniobate nanoparticles promoted a decrease in phytotoxicity, reduced pathogen resistance and, consequently, increased crop productivity. In environmental terms, a toxic product containing a carbon structure can be partially replaced by a non-toxic nanoparticulate material without carbon in its composition. This represents a leap in the development of new fungicides, reducing treatment time, increasing crop yields, improving harvest quality and reducing negative impacts on the environment and human health.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016]

[0015] Figure 1 represents (A) the particle sizes of polyoxoniobate (blue), prothioconazole (green) and the nanofungicide (yellow). It also represents (B) the Zeta potential values ​​of the same particles.

[0017]

[0016] Figure 2 represents the optimized structure, obtained by theoretical calculation (DFT, B3LYP functional and def2-TZVP basis function), of the PNB-PCZ nanofungicide composition. The light blue spheres represent niobium atoms.

[0018]

[0017] Figure 3 represents the results of the inhibition halo tests for (A) chlorhexidine (2%, w / v), used as a positive control, (B) polyoxoniobate (PNB) nanoparticles, (C) prothioconazole (PCZ) isolated, (D) PNB-PCZ, (E) FoxXpro fungicide isolated, (F) PNB-FoxXpro composition, (G) mancozeb isolated, (H) PNB-mancozeb composition, (I) azoxystrobin isolated and (J) PNB-azoxystrobin composition.

[0019]

[0018] Figure 4 represents the results obtained in situ experiments evaluating the synergistic potential between PNB and a commercial fungicide over 3, 10, 17 and 24 days after application.

[0020] DETAILED DESCRIPTION OF THE TECHNOLOGY

[0021]

[0019] The present technology deals with niobium-based nanofungicidal compositions and commercial fungicides. These compositions are formed by the association between polyoxoniobate nanoparticles and selected fungicidal products from the group of compounds containing triazoles, dithiocarbamates, strobilurins, and carboxamides. This association occurs through the direct mixing of both components. The product resulting from the association between polyoxoniobate nanoparticles and a fungicide composed of trifloxystrobin and cyproconazole was applied to plants, demonstrating synergism through the high percentage of inhibition after three days of application.

[0022]

[0020] In one embodiment of the technology, niobium-based nanofungicidal compositions are formed by mixing, in a ratio between 0.5:1 and 1.5:1 (v:v), preferably 1:1 (v:v), a solution with a concentration between 50 and 150 g / L -1 , preferably 100 gL -1, of polyoxoniobate nanoparticles with a solution at a concentration between 50 and 150 g / L 1 , preferably 100 gL -1 , of a fungicide selected from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof.

[0023]

[0021] In a preferred embodiment of the technology, the fungicide used in the antifungal composition may be 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1H-1,2,4-triazol-3-thione (proticonazole), 2-(4-chlorophenyl)-3-cyclopropyl I-1-(1H-1,2,4-triazol-1-yl)-2-butanol (cyproconazole), manganese ethyleneb / s (dithiocarbamate) zinc complex (polymeric) (mancozeb), A / -[2-(3,4-dichlorophenyl)-4-fluorophenyl]-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide (bixafen), A / -[9-(dichloromethylene)-1 ,2,3 ,4-tetrahydro- 1 ,4-methanonaphthalen-5-yl]-3-(difluoromethyl)-1 -methyl I- 1H-pyrazol-4-carboxamide (benzovindiflupir), (2E)-2-(2-{[6-(2-cyanophenoxy)pyrimidin-4-yl]oxy}phenyl)-3-methoxyprop-2-enoate methyl (azoxystrobin), (2E)- 2-methoxylimino-2-[2-[[(Z)-1 -[3-(trifluoromethyl)phenyl]ethylenediamino]oxymethyl]phenyl]acetate methyl (trifloxystrobin) or a combination thereof.

[0024]

[0022] Polyoxoniobates can be mixed with commercially available fungicides under specific names. Non-limiting examples of commercial fungicides suitable for the present technology include FoxXpro, marketed by Bayer and containing the compounds bixafen (125 gL). -1 ), protioconazole (175 gL -1 ) and trifloxystrobin (150 gL -1 ) (registered with the Ministry of Agriculture and Livestock (MAPA) under number 241 17), according to the associated Safety Data Sheet (SDS), available at https: / / www.agro.bayer.com.br / d / fungicida-bcs-fox-xpro-br and accessed on 06 / 21 / 2024. Another non-limiting example is the fungicide Evolution, marketed by UPL, which contains the compounds mancozeb (525 g / kg). -1 ), azoxystrobin (37.5 g.kg -1 ) and prothioconazole (37.5 g / kg) -1) (MAPA registration number 22121), according to the associated MSDS, available at https: / / www.upl-ltd.com / br / defensivos-agricolas / fungicida / evolution and accessed on 06 / 21 / 2024. Another non-limiting example is the fungicide Sphere Max, marketed by Bayer, which contains the compounds triploxystrobin (375 gL). 1 ) and ciproconazole (160 gL 1 ), according to the associated MSDS, available at https: / / www.agro.bayer.com.br / d / fungicida-bcs-sphere-max-br and accessed on 06 / 21 / 2024. Another non-limiting example is the fungicide Mitrion, marketed by Syngenta, which contains the compounds benzovindiflupir (75 gL -1 ) and protioconazole (150 gL 1 ), as per the associated SDS, available at https: / / www.syngenta.com.br / pro- duct / crop-protection / mitrion and accessed on 06 / 21 / 2024.

[0025]

[0023] In one embodiment of the present technology, the process for obtaining the compositions comprises the following steps: a. Preparing a solution of polyoxoniobate nanoparticles at a concentration between 50 and 150 g / L 1 , preferably 100 gL 1 b. Prepare a solution of a fungicide selected from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof, at a concentration between 50 and 150 g / L. 1 , preferably 100 gL 1 c. Add the solution prepared in “a” to the one prepared in “b”, in a ratio between 0.5:1 and 1.5:1 (v:v), preferably 1:1 (v:v); d. Keep the solution obtained in “c” under agitation for 10 to 60 minutes, preferably 30 minutes; e. Keep the solution obtained in “d” at rest for 12 to 36 hours, preferably 24 hours.

[0026]

[0024] In one embodiment of the present technology, the polyoxoniobate nanoparticles, dissolved in step “a” of the process to obtain the compositions, are obtained from the following steps: a. Add a solution with a concentration between 30 and 70% (v:v), preferably 50% (v:v), of hydrogen peroxide (H2O2) and water to niobium oxide (Nb2O5), in a H2O2:H2O:Nb2O5 ratio between 1:8:0.5 and 1:16:2 (v:v:m), preferably adding 4 ml of the H2O2 solution, 50 ml of water and 4.0 g of Nb2O5 (1:12.5:1 v:v:m); b. Stir the mixture obtained in “a” for 5 to 15 minutes, preferably 10 minutes; c. a. Keep the system obtained in “b” at rest for 6 to 18 hours, preferably 12 hours, at a temperature between 20 and 40 °C, preferably 27 °C; b. Separate the supernatant from the mixture obtained in “c” by centrifugation and collect the precipitate.

[0027]

[0025] In one embodiment of the present technology, the fungicide used in step “b” of the process to obtain the compositions may be 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1H-1,2,4-triazol-3-thione (prothioconazole), the zinc complex of manganese ethyleneb / s (dithiocarbamate) (polymeric) (mancozeb), A / -[2-(3,4-dichlorophenyl)-4-fluorophenyl]-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide (bixafen), methyl (2E)-2-(2-{[6-(2-cyanophenoxy)pyrimidin-4-yl]oxy}phenyl)-3-methoxyprop-2-enoate (azoxystrobin), 0 (2E)-2-methoxylimino-2-[2-[[(Z)-1-[3-(trifluoromethyl)phenyl]ethylenediamino]oxymethyl]phenyl]methyl acetate (trifloxystrobin) or a combination thereof.

[0026] In one embodiment of the present technology, the nanofungicidal compositions can be used for pest control in plants, acting as fungicides.

[0028]

[0027] In one embodiment of the present technology, polyoxoniobate nanoparticles can be used in the preparation of fungicidal compositions in combination with selected fungicides from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof.

[0029]

[0028] The present technology can be better understood through the following examples, which are not limiting.

[0030] EXAMPLE 1 - PROCESS FOR OBTAINING POLYOXONIOBATE NANOPARTICLES

[0031]

[0029] To obtain the polyoxoniobate (PNB) nanoparticles used in the antifungal compositions, the methodology described by Chagas was used (CHAGAS, P. Versatility of niobium-based compounds: application in residual glycerin oxidation, in photodynamic therapy and nanogel formation. Doctoral thesis, Federal University of Minas Gerais, 138 pp., 2019. Available at: http: / / hdl.handle.net / 1843 / SFSA-BBZTWG). The procedure involved adding 4.0 mL of a hydrogen peroxide (H2O2) solution (50%, v:v) and 50.0 mL of distilled water to 4.0 g of niobium oxide (Nb2Os). The system was stirred for 10 minutes and then left to stand for 12 hours at 27 °C. The supernatant was separated from the mixture by centrifugation and showed a yellow color.

[0032] EXAMPLE 2 - PROCESS FOR OBTAINING NIOBIUM-BASED NANOFUNGICIDE

[0033]

[0030] The nanofungicidal composition (PNB-PCZ) was obtained from mixing 100 mL of an aqueous solution of PNB, obtained according to the process described in Example 1, at a concentration of 100 g / L. -1 , with 100 mL of the fungicide prothioconazole (PCZ), at a concentration of 100 g / L 1, at room temperature. The mixture was kept at room temperature and constantly stirred for 30 minutes. The resulting solution was left to stand for 24 hours. Using this methodology, mixtures containing polyoxoniobate nanoparticles and the fungicidal compounds mancozeb and azoxystrobin were also prepared, in addition to the commercial product FoxXpro (containing bixafen, prothioconazole, and trifloxystrobin). The concentrations and preparation method of the compounds are the same as those described in the methodology for PCZ. The polyoxoniobate-fungicide compositions then encompassed the chemical groups ( / ) strobilurin, ( / 7) triazoles, (Hi) DMI (demethylation inhibitors), ( / ) carboxamide, (v) pyrazole carboxamide, (vi) triazolinthione, and (vii) carbamate.

[0034]

[0031] The resulting composition was analyzed by dynamic light scattering (DLS) and Zeta potential, as shown in Figure 1. In the particle size analysis (Figure 1A), the isolated PNB and PCZ compounds showed particle sizes of 28 and 90 nm, respectively. The combination of the molecules (PNB-PCZ) led to an increase in molecular size, reaching 147 nm. Thus, it can be suggested that the molecules combined, maintaining their structures and adding up the sizes after the combination. Figure 1B shows that the compounds separately presented an average Zeta potential of -90 mV (PCZ) and -32 mV (PNB). When combined, the PNB-PCZ composition presents a Zeta potential of -21 mV. It is important to highlight that niobium compounds mostly exhibit a negative charge due to the presence of surface hydroxyl groups.When these interact with the amine and hydroxyl groups of PCZ, hydrogen bonds are established and the charge of the combined molecule becomes less negative, indicating chemical interaction.

[0032] This is an important point of the present invention because the formation of new chemical bonds – and not just a mixture of compounds – characterizes the formation of a new chemical compound with sufficient stability to promote synergistic antifungal action and to be marketed.

[0035]

[0033] The composition structure was obtained by computational calculations using DFT (Density Functional Theory), with functional B3LYP and basis function def2-TZVP, as shown in Figure 2. It is possible to verify the hydrogen bonding between hydroxyl groups of PNB and nitrogen and halogen atoms of PCZ (characterizing classical and non-classical hydrogen bonds, respectively). Furthermore, energy minimization occurs in the formation of PNB-PCZ, corroborating the previous results. It is important to emphasize that, although illustrated in the present invention for interaction with PCZ, this technology is not limited to the antifungal in question, since the functional chemical groups present in other common antifungals, as discussed in previous paragraphs, resemble those observed in PCZ and the respective interactions with PNB occur in a similar way.

[0036] EXAMPLE 3 - IN VITRO EVALUATION OF THE SYNERGISTIC EFFECT OF POLYOXONIOBATE NANOPARTICLES COMBINED WITH FUNCTIONAL PRODUCTS

[0037] GICIDAS

[0038]

[0034] The nanofungicide PNB-PCZ, obtained from the procedure described in Example 2, was tested for its efficiency in inhibiting the growth of Candida albicans fungus. Prior to the experiments, C. albicans fungus was recovered in Brain Heart Infusion (BHI) broth at 36 °C for 18 hours. Antifungal susceptibility was evaluated according to the disk diffusion method. For this, sterile filter paper disks with a diameter of 6 mm received a 20 µL aliquot of the solution of each material to be tested (PNB, PCZ and PNB-PCZ) and then the disk was applied with sterile forceps onto a Petri dish containing Mueller-Hinton (MH) agar, previously inoculated with the fungus to be tested. For the disk diffusion test, halos with a diameter > 6 mm were considered to have inhibitory activity. A 2% (w / v) chlorhexidine solution was used as a control due to its well-known antifungal effect.

[0039]

[0035] The evaluation of the antifungal activity of the materials by the agar diffusion method (Figure 3) relates the size of the display zone (growth factors) or growth inhibition to the substance tested or its dosage. An increase in the inhibition halo was observed for all PNB-fungicide combinations (Figure 3D, F, H, J) compared to the isolated commercial fungicide (Figure 3C, E, G, I) and to PNB alone (Figure 3B). There were compositions that demonstrated a superior effect to the positive control (chlorhexidine 2%, w / v), particularly the PNB-Mancozeb and PNB-Azoxystrobin compositions. It is worth noting that PNB alone (Figure 3B) showed halo inhibition similar to the isolated fungicides PCZ, FoxXpro and azoxystrobin (Figure 3D, F and J). These results demonstrate the synergistic action of PNB with fungicides containing distinct functional groups, such as triazole rings (PCZ), dithiocarbamates (mancozeb), amides (FoxXpro), esters, nitriles, and pyrimidines (azoxystrobin).Therefore, polyoxoniobate nanoparticles showed an improved antifungal effect when combined with chemical functions commonly found in commercial products such as Evolution (containing the strobilurin azoxystrobin, mancozeb, and prothioconazole), FoxXpro (containing the carboxamide bixafen, prothioconazole, and the strobilurin trifloxystrobin), Sphere Max (containing trifloxystrobin and the triazole cyproconazole), and Mitrion (containing the carboxamide benzovindiflupir and prothioconazole).

[0040] EXAMPLE 4 - ON-SITE EVALUATION OF THE SYNERGISTIC EFFECT OF POLYOXONIOBATE NANOPARTICLES COMBINED WITH FUNCTIONS

[0041] GICIDAS

[0036] The field study was conducted combining PNB with the commercial fungicide Sphere Max, aiming to confirm the effect of combining the functional groups of PNB with the chemical groups in a field environment. The graph shown in Figure 4 shows the studies for the control of coffee rust, caused by the fungus Hemileia vastatrix in coffee cultivation. The experiment was conducted at the Agrogalaxy Technological Center - CTA, Alfenas unit, latitude S: 45.957851, longitude W: 21.404815, altitude of 831 m, in the state of Minas Gerais. The cultivar used was Catuai 62, the experimental design used was randomized blocks with 49 treatments and 4 replications.The results show that the combination with the niobium compound makes the ability to contain the coffee fungus more efficient, since the presence of Sphere Max alone promoted a containment of, at most, 50%, whereas, when combined with PNB, the containment reaches 77.5% just 3 days after application in the field.

Claims

CLAIMS 1. NINOBIUM-BASED NANOFUNGICIDAL COMPOSITIONS, characterized by comprising a mixture, in a ratio between 0.5:1 and 1.5:1 (v:v), of a solution with a concentration between 50 and 150 g / L 1 of polyoxoniobate nanoparticles in a solution with a concentration between 50 and 150 g / L 1 of a fungicide selected from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof.

2. COMPOSITIONS according to claim 1, characterized in that the fungicide is 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1H-1,2,4-triazol-3-thione, the zinc complex of manganese ethyleneb / s (dithiocarbamate) (polymer), A / -[2-(3,4-dichlorophenyl)-4-fluorophenyl]-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide, methyl (2E)-2-(2-{[6-(2-cyanophenoxy)pyrimidin-4-yl]oxy}phenyl)-3-methoxyprop-2-enoate, or methyl (2E)-2-methoxylimino-2-[2-[[(Z)-1 -[3-(trifluoromethyl)phenyl]ethylenediamino]oxy-methyl]phenyl]methyl acetate.

3. PROCESS FOR OBTAINING THE NANOFUNGICIDAL COMPOSITIONS defined in claim 1, characterized by comprising the following steps: a. Preparing a solution of polyoxoniobate nanoparticles at a concentration between 50 and 150 g / L 1b. Prepare a solution of a fungicide selected from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof, at a concentration between 50 and 150 g / L. 1 c. Add the solution prepared in “a” to the one prepared in “b”, in a ratio between 0.5:1 and 1.5:1 (v:v); d. Keep the solution obtained in “c” under agitation for 10 to 60 minutes; e. Keep the solution obtained in “d” at rest for 12 to 36 hours.

4. The PROCESS, according to claim 3, characterized in that, in step “a”, the polyoxoniobate nanoparticles are obtained from the following steps: a. Add a solution with a concentration between 30 and 70% (v:v) of hydrogen peroxide (H2O2) and water to niobium oxide (Nb2O2), in a H2O2:H2O:Nb2O2 ratio between 1:8:0.5 and 1:16:2 (v:v:m); b. Stir the mixture obtained in “a” for 5 to 15 minutes; c. Keep the system obtained in “b” at rest for 6 to 18 hours at a temperature between 20 and 40 °C; d. Separate the supernatant from the mixture obtained in “c” by centrifugation and collect the precipitate.

5. The process according to claim 3, characterized in that, in step “b”, the fungicide is 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1H-1,2,4-triazol-3-thione, the zinc complex of manganese ethyleneb / s (dithiocarbamate) (polymeric), A / -[2-(3,4-dichlorophenyl)-4-fluorophenyl]-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide, methyl (2E)-2-(2-{[6-(2-cyanophenoxy)pyrimidin-4-yl]oxy}phenyl)-3-methoxyprop-2-enoate, or methyl (2E)-2-methoxylimino-2-[2-[[(Z)-1 -[3-(trifluoromethyl)phenyl]ethylenediamino]oxy-methyl]phenyl]methyl acetate.

6. USE OF THE NANOFUNGICIDAL COMPOSITIONS defined in claim 1, characterized by being fungicides for application to plants.

7. USE OF POLYOXONIOBATE NANOPARTICLES, obtained by the process defined in claim 4, characterized by being in the preparation of fungicidal compositions in association with selected fungicides from the group containing triazoles, dithiocarbamates, strobilurins and carboxamides, or a combination thereof.

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