Environmentally friendly antifungal pesticide formulations based on silicon and zinc nanomaterials

Abstract

The present invention relates to a stable pesticide formulation comprising silicate, zinc oxide nanoparticles, vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, and a stabilizer or a mixture of stabilizers, which is useful for preventing or controlling plant diseases caused by microorganisms such as fungi or oomycetes. The present invention also relates to a method for preparing such a pesticide formulation. The pesticide formulation and method of the present invention facilitate the preparation of pesticide formulations containing silicate and zinc oxide nanoparticles, which further reduce the environmental impact caused by the application of pesticidal, bactericidal, fungicidal, and oomycete compounds.

Description

[Technical Field]

[0001] The present invention is in the field of agricultural chemistry, and in particular to pesticide formulations designed to provide physical and chemical protection to various plants and crops and to reduce the occurrence of pathogenic fungi in agricultural production. [Background technology]

[0002] By 2050, the world population is estimated to reach 9.4 billion, which would mean an increase in food production of approximately 50% ("Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds," Timothy R. Cook et al., Chem. Rev. 2010, 110, 6474-6502; "Can we improve global food security? A socio-economic and political perspective," Ulrike G., Food Sec. 2014, 6, 187-200). However, producing 50% more food requires permanent supplies of arable land, water, seeds, and fertilizer, as well as mechanisms for pest control, particularly insect and fungal control. Considering that 10-16% of the world's crops are lost to plant diseases every year, amounting to approximately $220 billion in losses ("Climate change, plant diseases and food security: an overview", Sukumar C. et al., Plant Pathology. 2011, 60, 2-14), it is clear that there is an urgent need to create a new generation of pesticides (insecticides and fungicides) that possess certain features, among others: (i) high availability of non-toxic raw materials, (ii) ease of manufacture, (iii) high specificity for the family of organisms, (iv) harmlessness of the substances that make up the fungicide to humans, mammals, and valuable insects such as bees, and (v) low environmental footprint of the fungicide synthesis.

[0003] Dithiocarbamates are one of the most widely used synthetic organic chemicals for preventing and controlling fungal plant diseases.Commercial fungicides containing these substances are widely used.However, this class of fungicides has drawbacks such as synthetic footprint, manufacturing complexity, and biotoxicity of active ingredients, which makes them unable to meet some of the desirable properties mentioned above.

[0004] Typically, the active compounds in fungicides have high efficiency and effectiveness in controlled laboratory assays, but it is well known that field use of these materials requires the creation of formulations containing adjuvants, binders, dispersants, antifoaming agents, and other molecules that improve the dispersal of the materials.

[0005] Various strategies are used to formulate products used to control pathogenic microorganisms. For example, U.S. Patent No. 8,404,263 discloses a pesticide formulation containing a pesticide, an organic UV photoprotective screener, and metal oxide coated nanoparticles. The object of the invention disclosed herein is to provide a composition that reduces the degradation of pesticide compounds due to exposure to sunlight, especially UV.

[0006] On the other hand, US Patent Application No. 2010 / 0016443 discloses a method for preparing particles of pesticide compounds containing a metal oxide coating and compositions containing such particles. The invention described therein allows for the isolation of the active compound (pesticide) and further allows for its controlled release.

[0007] Furthermore, patent applications EP0496106 and MX2017012740 disclose stable pesticide compositions comprising α-unsaturated amine derivatives, their salts, or iron sulfate compounds and liquid paraffin, respectively, which act as fungicidal insecticides for preventing plant and / or crop pests.

[0008] Considering the above, it can be concluded that commercially available fungicide formulations generally contain, among other things, a wide variety of organic adjuvants, fixatives, and dispersant molecules. The function of these molecules is to improve the application of the product and fix the active molecules to the plant for a long time, creating a residual effect. Since fungicides are applied by foliar spraying, the residual effect is transmitted to edible fruits and leaves. Therefore, new generation fungicides must contain chemicals in their formulations that are proven selective against pathogens and harmless to beneficial animals in crops, small mammals, and humans. It is also required that these substances do not contaminate soil or water sources.

[0009] Recent studies have shown that silicon has several functions in plant physiology, primarily in grasses. These physiological functions include resistance to toxicity caused by heavy metals, mechanical protection against pathogens, and in some cases, silicon is even considered an essential nutrient contributing to plant growth ("Silicon and Plant Diseases," Fabricio R. et al., Springer, 2015). In fact, according to "Benefits of plant silicon for crops: a review," Guntzer F, Agron Sustain Dev. 2012 32, 201-213, seven of the world's ten most produced crops are silicon accumulators, including corn, rice, sugar beet, sugarcane, and wheat.

[0010] Silicon has also been used to prevent and control diseases in various crops through a variety of strategies, such as controlling soil-borne and seed-borne diseases. Thus, according to a detailed review by Alessandro F. in "Silicon and Plant Diseases", Fabricio R. et al., Springer, Chapter 3, 2015, supplementing plant nutrients with silicon reduces the risk of diseases caused by the pathogens Phytophthora cinnamomi, Cylindrocladium spathiphylli, Fusarium oxysporum sp. cubense, Meloidogyne javanica, Phytophthora capsici, Meloidogyne exigua, Pythium aphanidermatum, and Fusarium moniliforme. The effects of certain diseases caused by Pythium moniliforme, Pythium ultimum, Pythium aphanidermatum sp. cucumerinum, Fusarium oxysporum sp. lactucae, Fusarium spp., and Meloidogyne spp. are reduced, particularly in avocados, bananas, red peppers, coffee, corn, cucumbers, lettuce, melons, rice, tomatoes, watermelons, and wheat. Silicates also help control foliar diseases of monocotyledonous and dicotyledonous plants caused by fungi, bacteria, and viruses.

[0011] On the other hand, according to "Benefits of plant silicon for crops: a review," Guntzer F, Agron Sustain Dev. 2012, 32, 201-213, the benefits of silicon for plants are more readily demonstrated under environmental stress. These benefits are summarized as improved resistance to pathogens and insects, drought relief, reduced incidence of stress due to high salt concentrations, improved uptake of potassium, phosphorus, and calcium, regulation of nutrient uptake (phosphorus and nitrogen) in excess, and alleviation of aluminum and zinc toxicity. In particular, silicon also provides plants with a mechanical advantage derived from the presence of silicon plant opal in their organic tissues, which increases their resistance to strong winds and rain and increases their resistance to insects.

[0012] One method of incorporating silicon into crop treatments is to spray plants with silicate solutions, which form a physical barrier on the plant surface that prevents pathogen infection. Recently, silicates have been shown to activate specific plant defense pathways against pathogens ("Silicon and Plant Diseases," Fabricio R. et al., Springer, 2015). Because silicates are non-toxic, they do not present the environmental concerns of other pesticides and pesticides. Their life cycle has not been shown to be toxic ("Soluble Silicates—Highly Versatile and Safe," CH. Baehr et al., International Journal for Applied Science, 2007, 133, 88-94). Furthermore, silicates promote plant health and prevent opportunistic attacks on plants by microorganisms or other harmful organisms.

[0013] However, while silicates have certain advantages as useful substances such as pesticides, silicate-containing mixtures are unstable because silicates precipitate at pH values ​​below 9. For this reason, formulations using silicates as active ingredients are sold in the form of sodium or potassium silicates, which have a pH value higher than 9. For example, Sil-MATRIX® is a potassium silicate formulation that functions as a preventative fungicide and is recommended for agricultural crops, particularly fruits and nuts. The formulation must be diluted before spraying on plants, and continuous stirring is recommended to ensure a thorough mixture, avoiding storage and mixing of diluted materials (http: / / www.certisusa.com / pdf-labels / Sil-Matrix_label.pdf). In addition to this drawback, another aspect is related to the poor foliar fixation ability of silicates in liquid form. This means that larger doses must be applied repeatedly and persistently to ensure the desired effect on crops.

[0014] On the other hand, recent studies have also shown that the use of nanomaterials, especially nanoparticles of transition metal oxides, exhibits significant reactivity in various physical and chemical processes. The reactivity of these materials is based on the nanoparticle material's large surface area, which provides a larger contact area with molecules or microorganisms in solution or on their surface. For example, silver (Ag) is a highly effective bactericide because it can bind to molecules with double bonds, especially those found in cell walls. The formation of such silver nanoparticle / cell wall complexes promotes cytoplasmic exposure and consequent cell death.

[0015] Several authors have also demonstrated that zinc oxide nanoparticles can generate cell wall openings in Campylobacter bacteria under controlled laboratory conditions ("Antibacterial Activity and Mechanism of Action of Zinc Oxide Nanoparticles against Campylobacter jejuni," Yanping X et al., Journal of American Society for Microbiology, 2011; 77(7): 2325-2331). Meanwhile, other authors have shown that zinc oxide nanoparticles combined with graphene also act as fungicides ("Synthesis, characterization, and enhanced antimicrobial activity of reduced graphene oxide-zinc oxide nanocomposite," Rajveer S et al., Mater. Res. Express, 2017, pp. 1-8). Meanwhile, Lili He et al. (2011) developed an assay demonstrating that zinc oxide nanoparticles have antifungal activity against Botrytis and Penicillium (Lili He, Yang Liu, Azlin Mustapha, Mengshi Lin, Microbiological Research. 2011, pp. 166-207, 207-215). These studies also demonstrate that the mechanism of action of zinc oxide nanoparticles can be controlled by cell wall modification, where contact with the nanoparticle material promotes deformation of the shape and size of fungal and bacterial cells, ultimately leading to cell death through wall opening. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] U.S. Patent No. 8,404,263 [Patent Document 2] U.S. Patent Application No. 2010 / 0016443 [Patent Document 3] EP0496106 [Patent Document 4] MX2017012740 [Non-patent literature]

[0017] [Non-Patent Document 1] "Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds", Timothy R. Cook et al., Chem. Rev. 2010, 110, 6474~6502 [Non-patent document 2] "Can we improve global food security? A socio-economic and political perspective", Ulrike G., Food Sec. 2014, 6, 187~200 [Non-patent document 3] “Climate change, plant diseases and food security: an overview”, Sukumar C. et al., Plant Pathology. 2011, 60, 2–14 [Non-patent document 4] “Silicon and Plan Diseases”, Fabricio R. et al., Springer, 2015 [Non-patent document 5] “Benefits of plant silicon for crops: a review”, Guntzer F, Agron Sustain Dev. 2012 32, 201~213 [Non-patent document 6] “Silicon and Plan Diseases”, Fabricio R. et al., Springer, Chapter 3, 2015 [Non-Patent Document 7] "Soluble Silicates-Highly Versatile and Safe", CH. Baehr et al., International Journal for Applied Science, 2007, 133, 88-94 [Non-patent document 8] http: / / www.certisusa.com / pdf-labels / Sil-Matrix_label.pdf [Non-Patent Document 9] “Antibacterial Activity and Mechanism of Action of Zinc Oxide Nanoparticles against Campylobacter jejuni”, Yanping X et al., Journal of American Society for Microbiology, 2011; 77(7): 2325~2331 [Non-Patent Document 10] “Synthesis, characterization and enhanced antimicrobial activity of reduced graphene oxide-zinc oxide nanocomposite”, Rajveer S et al., Mater. Res. Express, 2017, 1–8 [Non-Patent Document 11] Lili He., Yang Liu., Azlin Mustapha., Mengshi Lin., Microbiological Research. 2011, 166, 207~215 [Non-Patent Document 12] "Synthesis and characterization of zinc oxide nanoparticles: application to textiles as UV-absorbers", Becheri A. et al., J. Nanopart. Res, 10: 679~689 [Non-Patent Document 13] "Low temperature synthesis of ZnO nanoparticles using mechanochemical route: a green chemistry approach" Azam A et al., IJTAS, 2009, 1(2): 12~14 Summary of the Invention [Problem to be solved by the invention]

[0018] Despite the potential of zinc oxide nanoparticles as bactericides and fungicides, the stabilization and formulation of the nanomaterials presents technical challenges. [Means for solving the problem]

[0019] The present invention describes the preparation of stable pesticide formulations comprising silicate and zinc oxide nanoparticles together with vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, and a stabilizer or a mixture of stabilizers. The silicate-containing pesticide formulations of the present invention prevent and treat problems associated with plant diseases caused by phytopathogenic fungi, and are characterized by the use of non-toxic chemicals that are organic, harmless to humans and beneficial organisms, and have little impact on the environment in their production.

[0020] The present invention relates to a pesticide formulation comprising a silicate, a vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, zinc oxide nanoparticles, and a stabilizer or a mixture of stabilizers, as well as a method for preparing the pesticide formulation. In particular, the formulation is characterized by being stable for a long period of time and being useful for preventing and controlling plant diseases caused by microorganisms such as fungi or oomycetes. Therefore, the pesticide formulation is useful in the agricultural industry as a natural or organic fungicide with low environmental impact. [Brief explanation of the drawings]

[0021] [Figure 1]Powder X-ray diffraction patterns of (A) sol-gel synthesized ZnO nanoparticles (Example 1), (B) dry-synthesized ZnO nanoparticles (Example 2), and (C) commercially available USP ZnO nanoparticles. [Figure 2] FT-IR spectra of ZnO nanoparticles: (A) sol-gel synthesis (Example 1) and (B) dry synthesis (Example 2). [Figure 3] UV-VIS spectra of zinc oxide nanoparticles: (A) dry synthesis in solvent HO, (B) sol-gel synthesis in solvent HO, (C) sol-gel synthesis in solvent PEP-HO, and (D) sol-gel synthesis in solvent PEP-CHHO. [Figure 4] Scanning electron microscope (SEM) images of: (A) dry-synthesized zinc oxide nanoparticles; (B) sol-gel synthesized zinc oxide nanoparticles; (C) commercially available USP zinc oxide nanoparticles. [Figure 5] 1A-C are scanning electron microscope (SEM) photographs of pesticide formulations of Example 7: (A) pesticide formulation D; (B) pesticide formulation F; and (C) pesticide formulation H. [Figure 6] 1 is a UV-VIS spectra (10 days) of the pesticide formulations of Example 7: (A) Pesticide Formulation D and (B) Pesticide Formulation H. [Figure 7] 1 is a diagram of the stability curves of the pesticide formulations of Example 7: (A) Pesticide Formulation D (B) Pesticide Formulation F and (C) Pesticide Formulation H. [Figure 8A] FIG. 1 shows antifungal activity of the pesticide formulations of Example 7 against B. cinerea over time: (A) Pesticide formulation D1. [Figure 8B] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against B. cinerea: (B) Pesticide formulation F1. [Figure 8C] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against B. cinerea: (C) Pesticide formulation H1. [Figure 8D] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against B. cinerea: (D) Pesticide formulation I. [Figure 8E] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against B. cinerea: (E) Pesticide formulation J. [Figure 9A] Figure 1. Antifungal activity of the pesticide formulations of Example 7 against M. fijiensis over time: (A) Pesticide formulation D1. [Figure 9B] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against M. fisiensis over time: (B) Pesticide formulation F1. [Figure 9C] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against M. fijiensis over time: (C) Pesticide formulation H1. [Figure 9D] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against M. fisiensis over time: (D) Pesticide formulation I. [Figure 9E] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against M. fijiensis over time: (E) Pesticide formulation J. [Figure 10A] FIG. 1 shows antifungal activity of the pesticide formulations of Example 7 against P. palmivora over time: (A) Pesticide formulation D. [Figure 10B] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against P. palmivora: (A) Pesticide formulation F; [Figure 10C] Figure 10. Antifungal activity of the pesticide formulations of Example 7 over time against P. palmivora: (C) Pesticide formulation H. [Figure 10D] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against P. palmivora over time: (D) Pesticide formulation I. [Figure 10E] Figure 10. Antifungal activity of the pesticide formulations of Example 7 against P. palmivora over time: (E) Pesticide formulation J. [Figure 11A] Figure 1. Antifungal activity of the pesticide formulations of Example 7 over time against P. infestans: (A) Pesticide formulation D. [Figure 11B] Figure 1. Antifungal activity of the pesticide formulations of Example 7 over time against P. infestans: (A) Pesticide formulation F; [Figure 11C]Figure 1. Antifungal activity of the pesticide formulations of Example 7 over time against P. infestans: (C) Pesticide formulation H. [Figure 11D] Figure 1. Antifungal activity of the pesticide formulations of Example 7 over time against P. infestans: (A) Pesticide formulation I; (B) Pesticide formulation II. [Figure 11E] Figure 1. Antifungal activity of the pesticide formulations of Example 7 over time against P. infestans: (E) Pesticide formulation J. [Figure 12A] (A) Time-based antifungal activity of commercial fungicides against B. cinerea: Siganex (C1), Mancozed 80% WP (C2), and Forum 500 WP (C3). [Figure 12B] (B) Time-dependent antifungal activity of commercial fungicides against M. fisiensis: Siganex (C1), Mancozed 80% WP (C2), and Forum 500 WP (C3). [Figure 12C] (C) Time-based antifungal activity of commercial fungicides against P. palmivora: Siganex (C1), Mancozed 80% WP (C2), and Forum 500 WP (C3). [Figure 12D] (D) Time-based antifungal activity of commercially available fungicides against P. infestans: Siganex (C1), Mancozed 80% WP (C2), and Forum 500 WP (C3). DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention relates to a pesticide formulation comprising silicate and zinc oxide nanoparticles in a liquid matrix, the pesticide formulation containing a vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, and a stabilizer or a mixture of stabilizers, as well as a method for preparing the pesticide formulation. In particular, the present invention provides a pesticide formulation comprising silicate and zinc oxide nanoparticles that is stable over time.

[0023] For purposes of this application, the term "silicate" or "silicate salt" refers to (SiO) 2- It refers to a salt comprising an anion and any cation, including, but not limited to, sodium, potassium, manganese, magnesium, and calcium. In one embodiment of the present invention, the silicate or silicate salt is selected from potassium silicate, sodium silicate, manganese silicate, magnesium silicate, and calcium silicate.

[0024] The silicate is contained in the pesticide formulation of the present invention at a concentration of 0.01 to 250 g / L. In another embodiment of the present invention, the concentration is 0.05 to 240 g / L, 0.1 to 230 g / L, 0.5 to 220 g / L, 0.8 to 210 g / L, 1.0 to 200 g / L, 1.5 to 190 g / L, 2.0 to 180 g / L, 2.5 to 170 g / L, 3.0 to 160 g / L, 3.5 to 150 g / L, 4.0 to 140 g / L, 4.5 to 130 g / L, 5.0 to 160 g / L, 5.5 to 150 g / L, 6.0 to 140 g / L, 7.0 to 150 g / L, 8.0 to 160 g / L, 9.0 to 170 g / L, 10.0 to 180 g / L, 10.0 to 180 g / L, 10.0 to 190 g / L, 11.0 to 180 g / L, 12.0 to 190 g / L, 13.0 to 160 g / L, 14.0 to 180 g / L, 15.0 to 190 g / L, 16.0 to 180 g / L, 17.0 to 190 g / L, 18.0 to 190 g / L, 19.0 to 200 g / L, 20.0 to 210 g / L, 21.0 to 220 g / L, 22.0 to 230 g / L, 23.0 to 240 g / L, 24.0 to 2 g / L, 5.0-120g / L, 5.5-110g / L, 6.0-100g / L, 6.5-95g / L, 7.0-90g / L, 8.5-85g / L, 9.0-80g / L, 10-75g / L, 15-70g / L, 20-65g / L, 25-60g / L, 30-55g / L, 35-50g / L, 40-45g / L.

[0025] Furthermore, the term "vegetable oil" refers to a viscous liquid mixture at room temperature extracted from plants and composed of non-polar compounds, primarily triglycerides. Usable vegetable oils include, but are not limited to, soybean oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, canola oil, safflower oil, sesame oil, sunflower oil, hazelnut oil, almond oil, walnut oil, macadamia oil, pecan oil, and pistachio oil. In one embodiment of the present invention, the vegetable oil is selected from the group consisting of soybean oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, canola oil, safflower oil, sesame oil, and sunflower oil. The vegetable oil is present in a concentration of between 0.001 and 5.0% v / v, between 0.01 and 3.0% v / v, and between 0.1 and 1.0% v / v.

[0026] Furthermore, the term "surfactant" as used in this application refers to a compound that contains polar and non-polar groups and reduces the surface tension of a liquid or the interfacial tension between two immiscible substances. Synonyms are "surfactant" and "surface-active agent." The surfactant that constitutes the pesticide formulation of the present invention is selected from ionic and non-ionic surfactants. In one embodiment of the present invention, the surfactant is non-ionic. For example, the non-ionic surfactant is selected from the group including, but not limited to, ethoxylated linear alcohols, ethoxylated alkylphenols, fatty acid esters, amine derivatives, amide derivatives, alkyl polyglucosides, ethylene glycol / propylene glycol copolymers, polyols, ethoxylated polyols, thiols (mercaptans), and derivatives thereof or mixtures thereof. In particular, the nonionic surfactant is selected from the group including, but not limited to, polysorbate, poloxamer, octyl glycoside, polyglycerol, polyricinoleate, Triton X-100, cetyl alcohol, and Cirrasol. In particular, the nonionic surfactant may be polysorbate 20 (Tween 20), polysorbate 40 (Tween 40), polysorbate 60 (Tween 60), polysorbate 65 (Tween 65), polysorbate 80 (Tween 80), Cirrasol, or a mixture thereof. The surfactant or mixture of surfactants is present at a concentration of between 0.0001 and 1% v / v, 0.001 and 0.1% v / v, and 0.001 and 0.01% v / v.

[0027] As used herein, the term "thickener" refers to a compound that increases the viscosity of a liquid. A synonym for this term is "viscosifier." The thickener or viscosifier that constitutes the formulation of the present invention is an organic substance, a polysaccharide, a protein, a thickener or viscosifier, a derivative thereof, or a mixture thereof. For example, polyvinyl alcohol, methylcellulose, xanthan gum, hydroxymethylcellulose, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, gellan gum, guar gum, locust bean gum, tragacanth gum, succinoglucan gum, gelatin, carrageenan, starch, sago, tapioca, pectin, collagen, and agar. In particular, the thickening agent or thickener is a polysaccharide such as methylcellulose, xanthan gum, hydroxymethylcellulose, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, gellan gum, guar gum, locust bean gum, tragacanth gum, succinoglucan gum, gelatin, carrageenan, starch, agar, etc. The thickening agent may be present in a concentration between 0.0001 and 10.0 g / L, 0.001 and 8.0 g / L, 0.01 and 6.0 g / L, or 0.1 and 4.0 g / L.

[0028] As used herein, the term "nanofluid" refers to a fluid containing uniformly and stably suspended nanoparticles.

[0029] As used herein, the term "stable" refers to a formulation containing silicate and zinc oxide nanoparticles that remains homogeneous without separation of its components or phases for a storage time of more than 30 days.

[0030] In one embodiment of the present invention, the pesticide formulation is in the form of an emulsion consisting of a two-phase system in which one immiscible liquid is uniformly dispersed in the other. In this invention, the two phases are formed by silicate and vegetable oil, along with a surfactant. The emulsion also contains zinc oxide nanoparticles. As used in this application, the term "nanoparticles" refers to particles having a size between 1 and 999 nm.

[0031] In one embodiment of the present invention, the pesticide formulation comprises silicate, vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, a stabilizer or a mixture of stabilizers, and zinc oxide nanoparticles. The zinc oxide nanoparticles are at a concentration of 0.1 to 300 g / L. In one embodiment of the present invention, the zinc oxide nanoparticles have a size of 1 to 100 nm, 10 to 80 nm, 25 to 80 nm, or 25 to 50 nm.

[0032] In a further embodiment of the present invention, the pesticide formulation comprises silicate, vegetable oil, a surfactant or a mixture of surfactants, a stabilizer or a mixture of stabilizers, zinc oxide nanoparticles, and further comprises a dispersant or a mixture of dispersants. As used herein, the term "dispersant" refers to a substance that prevents zinc oxide nanoparticles from agglomerating and allows them to remain dispersed in solution. In one embodiment of the present invention, the dispersant is selected from a mixture of ammonium citrate and glycerol (in a ratio of 1:1.5) and sodium hexametaphosphate. The dispersant is present in a concentration of 0.1-500 g / L, 0.5-400 g / L, 1.0-300 g / L, 5.0-200 g / L, 10.0 g / L-100 g / L, and 0.1-40 g / L.

[0033] The zinc oxide nanoparticles incorporated into the pesticide formulations of the invention can be synthesized by any technique known to a person of average knowledge in the subject, in particular by colloidal methods, photochemical and radiochemical reduction, microwave irradiation, the use of dendrimers, solvothermal synthesis, sol-gel synthesis, dry synthesis, etc. In one embodiment of the present invention, the zinc nanoparticles are synthesized by a modification of the sol-gel methodology developed by Becheri A. et al., "Synthesis and characterization of zinc oxide nanoparticles: application to textiles as UV-absorbers", J. Nanopart. Res, 10: 679-689, and by a modification of the methodology developed by Azam A. et al., "Low temperature synthesis of ZnO nanoparticles using mechanochemical route: a green chemistry approach", IJTAS, 2009, 1(2): 12-14.

[0034] The preparation of the aforementioned agrochemical formulations, which correspond to the modalities of the present invention, is carried out by the following method: a formulation comprising silicate, vegetable oil, a surfactant or a mixture of surfactants, a dispersant or a mixture of dispersants, zinc oxide nanoparticles, and a stabilizer or a mixture of stabilizers, is carried out by the following steps: a) mixing an aqueous silicate solution with vegetable oil; b) adding a surfactant or a mixture of surfactants; c) adding a stabilizer or a mixture of stabilizers; d) preparing a nanofluid comprising zinc oxide nanoparticles and a dispersant; e) mixing the product obtained in step a) with the nanofluid according to step d). f) diluting the agrochemical composition from step e) with water to the desired concentration; The method is prepared according to the method comprising:

[0035] The formulations of the present invention are intended to be used for the prevention or control of plant diseases caused by microorganisms. For example, the plants may be vegetables, fruit- or fruit-bearing plants, ornamental plants, medicinal plants, legumes, cereals and tubers. In particular, chard (Beta vulgaris), chili peppers (Capsicum spp.), garlic and onions (Allium spp.), celery (Celery graveolens), eggplant (Solanum meolongena), pumpkin (Curcurbita moschata), chayote (Sechium edule), cabbage (Brassica oleracea), spinach (Spinaca oleracea), beans (Phaseolus vulgaris), lettuce (Lactuca sativa), and cucumber (Cucumber sativa). sativa), corn (Zea mays), peanut (Arachis hypogaea), tomato (Solanum lycopersicum), cucumber (Cucumis sativus), okra (Hibiscus esculentus), radish (Raphanus sativus), beetroot (Beta vulgaris), carrot (Daucus carota), avocado (Persea americana), sugar apple (Annona squamosa), caimito (Chrysophyllum cainito), cainito), Canistel (Pouteria campechiana), Cherry (Malpighia punicifolia), Custard apple (Annona reticulata)reticulata), plum (Spondias dulcis), coconut (Cocos nucifera), papaya (Carica papaya), soursop (Annona muricata), guava (Psidium guajava), pomegranate (Punica granatum), lime (Citrus aurantifolia), lemon (Citrus limonum), red mamey (Calocarpum mammosum), mamey Santo Domingo (Mammea americana), Melicocca tree (Melicocea bijuga), bijuga), mandarin (Citrus reticulata), mango (Mangifera indica), passion fruit (Passiflora laurifolia), watermelon (Citrullus vulgaris), bitter orange (Citrus aurantium), sweet orange (Citrus sinensis), pineapple (Ananas comosus), banana (Musa paradisiaca), plantain (Musa balbisiana), tamarind (Tamarindus indica), indica), grapefruit (Citrus paradisi), Creole grapefruit (Citrus grandis), grapes (Vitis vinifera) ,toCorn (Zea mays), rice (Oryza sativa), coffee (Coffea arabica), sugarcane (Saccharum officinarum), cotton (Gossypium hirsutum), gherkin (Melothria guadalupensis), sweet potato (Ipomoes batatas), potato (Solanum tuberosum), Creole potato (Solanum phureja), Cape gooseberry (Physalis peruviana), cassava (Manihot esculenta), Crops include: soybean (Glycine max), strawberry (Fragaria spp.), blackberry (Morus spp.), brambleberry (Rubus spp.), palm (Elaeis guineensis), cocoa (Theobroma cacao), tomato (Solanum betaceum), and lulo (Solanum quitoense).

[0036] In particular, the microorganism is a bacterium, a fungus or an oomycete. For example, bacteria such as Pseudomonas syringae, Ralstonia solanacearum, Agrobacterium tumefaciens, Xanthomonas spp. (Xanthomonas oryzae pv. oryzae, Xanthomonas campestris, Xanthomonas axonopodis, Erwinia amylovora, Xylella fastidiosa, Dickeya dadantii, Dickeya solani) solani, Pectobacterium carotovorum, Pectobacterium atrosepticum, Clavibacter michiganensis, Clavibacter sepedonicus, and Pseudomonas savastanoi.In particular, fungi include Magnaporthe oryzae, Botrytis cinerea, Puccinia spp. (including but not limited to Fusarium graminearum, Fusarium oxysporum), Blumeria graminis, Mycosphaerella spp. (including but not limited to Mycosphaerella fijiensis, and Mycosphaerella graminicola), Colletotrichum spp., Ustilago maydis, Melampsora linii, lini, Phakopsora pachyrhizi, and Rhizoctonia solani. With regard to oomycetes, this may be Phytophthora spp. (including, but not limited to, Phytophthora infestans, Phytophthora ramorum, Phytophthora sojae, Phytophthora capsici, Phytophthora cinnamomi, Phytophthora palmivora, Phytophthora parasitica, Hyaloperonospora arabidopsidis, Plasmopara viticola, Pythium ultimum, Albugo Candida, and Peronospora farinosa). [Example]

[0037] Example 1 Sol-gel synthesis of ZnO nanoparticles A quantity of 5.5 g of ZnCl2 was dissolved in 200 mL of water at 90 °C in an oil bath. Then, 16 mL of 5 M NaOH was added dropwise to the ZnCl2 solution with gentle stirring at 90 °C over a period of 10 minutes. The particles were separated from the supernatant dispersion by sedimentation, and the supernatant was discarded. The suspension was washed five times with distilled water, and the removal of NaCl from the suspension was measured with an AgNO3 solution to reduce the NaCl concentration to less than 1 μM. The resulting purified particles were peptized with 2-propanol in an ultrasonic bath for 10 minutes to break down micro-agglomerates and obtain ZnO nanounits. The particles were then separated by centrifugation at 6000 rpm for 15 minutes. The washing procedure was performed three times. Finally, the particles were exposed to 250 °C for 5 hours, yielding 1.5 g of zinc oxide nanoparticles.

[0038] Example 2 Dry synthesis of ZnO nanoparticles Zinc acetate (21.9 g) and tartaric acid (18 g) were ground and mixed in an agate mortar at room temperature for 30 minutes to produce zinc tartrate, which was then heated to 450°C for 1 hour to obtain 7 g of zinc oxide nanoparticles.

[0039] Example 3 X-ray powder diffraction characterization of ZnO nanoparticles As can be seen in Figures 1A and 1B, the zinc oxide nanoparticles synthesized according to Examples 1 and 2 exhibit a crystalline structure corresponding to the hexagonal wurtzite phase with similar lattice parameters (a = 3.251 yc = 5.205 Å). No additional phases were observed, ensuring the purity of the resulting compounds. In particular, the diffraction pattern obtained from the synthesized nanoparticles shows the same peaks as commercially available USP nanoparticles (Figure 1C).

[0040] Example 4 Characterization of ZnO nanoparticles by FT-IR spectroscopy The FT-IR spectra (FIGS. 2A and 2B) of the zinc oxide nanoparticles synthesized according to Examples 1 and 2 show a peak at 430 cm -1The Zn-O absorption bands around 3450 and 2350 cm are shown. -1 The peaks at -0.05 indicate the presence of trace amounts of -OH and C=O, likely due to moisture and CO2 present in the atmosphere. The same spectra were obtained from nanoparticles produced by the following methods: dry synthesis (ST SC), sol-gel synthesis (ST SOL-GEL), sol-gel synthesis with 2-propanol pectization (ST SOL-GEL PECT), and sol-gel synthesis with 2-propanol pectization and oven drying at 120 °C (ST SOL-GEL PECT SC).

[0041] In the FT-IR spectrum, the analytical precursor, ZnO nanoparticles (ZnO NPs SS Analit) synthesized by dry synthesis, had a wavelength of 400 cm -1 The strong band of was interpreted as the presence of zinc oxide, and the same synthesis was used with the precursor tartaric acid replaced by commercial tartaric acid (ZnO NPs SS AT) showed similar spectra, and the compound ZnO USP also showed the same spectrum.

[0042] Example 5 Characterization of ZnO nanoparticles by UV-visible spectroscopy Figures 3A, 3B, 3C, and 3D show UV-Vis spectra of zinc oxide nanoparticles synthesized according to Examples 1 and 2 using different solvents. Absorbance is plotted at 372 and 362 nm for the aqueous and organic solutions. The highest absorbance of 1.72 nm is observed for the sol-gel synthesis in deionized water with peptization (ST SOL-GEL PECT-HO), with intermediate values ​​of 0.36–0.56 corresponding to the sol-gel synthesis in distilled water (ST SOL-GEL-HO) and 2-propanol (ST SOL-GEL PECT-C3HO). A lower absorbance of 0.228 corresponds to the dry synthesis in deionized water (ST SC-HO), the latter value also reported by the authors for typical ZnO nanoparticles [4, 6].

[0043] By UV-Vis spectroscopy, zinc oxide is reported to have an absorbance between 0.22% and 1.80% in the wavelength range of 370-390 nm, which allows for qualitative identification and assessment of the compound's stability and purity.

[0044] Example 6 Characterization of ZnO nanoparticles by scanning electron microscopy (SEM). As can be seen in Figure 4, the zinc oxide nanoparticles of Example 2 (Figure 4A) are either spherical with diameters between 25 and 47.2 nm, or irregular and form aggregates. For the zinc oxide nanoparticles synthesized in Example 1 (Figure 4B), the particles form aggregates of well-defined petal-shaped sheets with widths of 29.83 nm and lengths of 72.05 nm. Finally, for the commercially available USP zinc oxide nanoparticles (Figure 4C), the particles are in the form of well-defined rods with lengths of 205 to 500 nm and bases of 99 to 177 nm, as well as aggregates with several shapes.

[0045] Example 7 Preparation of pesticide formulations Various formulations (Formulations A to H) according to the concentrations shown in Tables 1 to 5 were tested. For this purpose, two initial compositions were prepared. The first composition was initially K 2 SiOA 340% w / v aqueous solution was prepared by mixing soybean oil, then adding Tween 80 and Cirrasol, and finally adding xanthan gum. A second composition was prepared by first mixing ZnO nanoparticles with ammonium citrate and glycerol in a ball mill, then ultrasonically mixing for 10 minutes. Finally, both compositions were mixed together. As shown in Tables 1-5, not all formulations contain all components. If one of the components was missing, the procedure was simply continued by omitting the step related to that component. Alternatively, concentrated formulations were prepared according to the methods described above, and then diluted to obtain other concentrations. For example, the formulations in Tables 2-5 were also prepared by diluting the concentrated formulation in Table 1 with water. Thus, the formulations of Table 2 exhibit a dilution factor equal to 40 relative to the formulations of Table 1, the formulations of Table 3 exhibit a dilution factor equal to 200 relative to the formulations of Table 1, the formulations of Table 4 exhibit a dilution factor equal to 400 relative to the formulations of Table 1, and the formulations of Table 5 exhibit a dilution factor equal to 800 relative to the formulations of Table 1.

[0046] [Table 1]

[0047] [Table 2]

[0048] [Table 3]

[0049] [Table 4]

[0050] [Table 5]

[0051] Example 8 Stability evaluation of the formulation of the present invention The stability of formulations D, F, and H was determined by EDS, SEM (Figure 5), UV-Vis spectroscopy (Figures 6A and 6B), and Turbiscan techniques, the latter two evaluating the stability of the formulations over a 10-day period. Considering the EDS results, the presence of zinc, oxygen, and carbon is evident in formulation D. Furthermore, the formulation exhibits spherical, irregularly shaped, aggregated, and fully coated zinc oxide nanoparticles with particle sizes between 42 and 60 nm (Figure 5A). Formulation F is characterized by the presence of zinc, oxygen, carbon, silicon, and potassium. Furthermore, the formulation exhibits spherical, irregularly shaped, and fully coated zinc oxide nanoparticles with particle sizes between 22 and 47.4 nm, along with spherical aggregates with diameters between 542.0 and 638.2 nm, within a linear network of the formulation's emulsifying compounds (Figure 5B). Finally, the presence of zinc, oxygen, silicon, and potassium is evident in formulation H. The zinc oxide nanoparticles in formulation H ranged in size from 24.0 to 68.0 nm and had spherical shapes with varying degrees of aggregation, spherical variations, and polygonal shapes, all within a linear network of the formulation's emulsifying compounds that surrounded and coated the particles (Figure 5C). All formulations evaluated demonstrated high stability over time, as evidenced in Figure 7.

[0052] Example 9 Antifungal activity evaluation of the formulation of Example 7 The antifungal activity of formulations D, F, H, I, and J of Example 7, as well as their 1 / 2 and 1 / 4 dilutions, was tested against four microorganisms: Botrytis cinerea ATCC 36634, Mycosphaerella fijiensis ATCC 36055, Phytophthora palmivora ATCC 46634, and Phytophthora infestans ATCC 48716. To compare the efficacy of the formulations of the present invention, commercially available fungicides and oomyceticides were also tested: Misilk 360, Nitrofil FT, Siganex, Mancozeb 80% WP, and Forum 500 WP. Furthermore, to determine the effect of ZnO nanoparticle size, the aforementioned formulations were prepared using commercially available zinc oxide USP, which features a larger particle size than the nanoparticles used in the formulations of the present invention. Formulations containing commercially available USP zinc oxide are indicated with an asterisk (*).

[0053] Fungi and oomycetes were cultured and grown on 2% potato dextrose agar (PDA) at 24±1°C for 7 to 30 days, depending on the strain. They were then inoculated onto fresh PDA medium containing the formulations of the present invention. The formulations were used at the concentrations shown in Tables 3, 4, and 5, with sterile distilled water used as a control. Radial growth of the pathogens was then measured over time using a caliper. All assays were performed in triplicate. The formula used to calculate the percent inhibition is as follows:

[0054]

number

[0055] Table 6 shows the results obtained for B. cinerea ATCC 36634 after 7 days of growth for the evaluated formulations (Figures 8A, 8B, 8C, 8D, and 8E). Results obtained on day 7 of the assay indicated that formulations F and H exhibited the highest in vitro antifungal activity against Botrytis cinerea, with growth inhibition rates ranging from 80 to 99% compared to the growth control without antifungal agent. The antifungal activity of formulations F and H at the highest concentrations evaluated was comparable to that exhibited by the commercially available fungicides Siganex and Mancozeb (Figure 12A).

[0056] The results of M. fisiensis ATCC 36055 growth inhibition at day 40 for the evaluated formulations are shown in Table 7 (Figures 9A, 9B, 9C, 9D, and 9E). The growth of the fungus remained stable even up to day 55. Therefore, day 40 was considered the maximum point of radial growth of the fungus. Considering the results, formulations D, H, and H* inhibited fungal growth by 100%, similar to the commercial fungicide evaluated as an inhibition control, and showed the best in vitro antifungal activity against M. fisiensis strain (Figure 12B).

[0057] Similarly, the results obtained for the P. palmivora ATCC 46634 strain on day 17 of the evaluated formulations are shown in Table 8 (Figures 10A, 10B, 10C, 10D, and 10E). The results show that compounds F, H, H*, and Misilk 360 (Figure 12C) showed the highest P. palmivora activity (greater than 94% growth inhibition compared to the control) even at the lowest evaluated concentration (dilution factor 800). With the exception of compound Nitrofil FT, the evaluated formulations inhibited more than 99% of the oomycete at the highest concentration.

[0058] The results of the evaluated formulations' growth inhibition of P. infestans ATCC 46634 at day 20 (Figures 11A, 11B, 11C, 11D, and 11E) are shown in Table 9. The results obtained show that the formulations of the present invention, except for compound (J), can inhibit the growth of P. infestans by 98-100%.

[0059] In conclusion, the highest concentrations of formulations F, F*, H, and H* appear to be the formulations exhibiting the best antifungal or antioomycete activity in vitro, comparable to the commercial fungicides Siganex, Mancozeb 80% WP, and Forum 500 WP against the various plant pathogens evaluated.

[0060] [Table 6]

[0061] [Table 7]

[0062] [Table 8]

[0063] [Table 9]

Claims

1. - silicates between 0.01 and 250 g / L; - between 0.001 and 5.0% v / v of a vegetable oil selected from the group consisting of soybean oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, canola oil, safflower oil, sesame oil and sunflower oil; - between 0.0001 and 1% v / v of a surfactant selected from the group consisting of polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 65, polysorbate 80, or mixtures thereof; a dispersant selected from a mixture of ammonium citrate, glycerol and sodium hexametaphosphate, at between 0.1 and 500 g / L; - zinc oxide nanoparticles between 0.1 and 300 g / L; and - between 0.0001 and 200 g / L of a stabilizer which is a thickener selected from the group consisting of xanthan gum, gum arabic, gellan gum, guar gum, locust bean gum, tragacanth gum, succinoglucan gum Including, the silicate is selected from sodium silicate and potassium silicate; A liquid pesticide formulation in the form of an oil-in-water emulsion, wherein the size of said zinc oxide nanoparticles is between 1 and 100 nm.

2. 10. A method for preparing the pesticide formulation of claim 1, comprising: a) mixing an aqueous solution of silicate with said vegetable oil; b) adding said surfactant or mixture of surfactants; c) adding the stabilizer; d) preparing a nanofluid comprising zinc oxide nanoparticles and said dispersant; e) mixing the product obtained in step c) with the nanofluid according to step d); f) Diluting the agrochemical composition from step e) with water to the desired concentration A method comprising:

3. 10. Use of the pesticide formulation according to claim 1 for the prevention or control of plant diseases caused by microorganisms selected from the group consisting of fungi and oomycetes.

4. The plant may be chard (Beta vulgaris), chili pepper (Capsicum spp.), garlic and onion (Allium spp.), celery (Celery graveolens), eggplant (Solanum melongena solanum), pumpkin (Cucurbita moschata), chayote (Cesium edulis), cabbage (Brassica oleracea), spinach (Spinochetia oleracea), bean (Phaseolus vulgaris), lettuce (Lactuca sativa), corn (Zea mays), peanut (Arachis hypogaea), tomato (Solanum lycopersicum), cucumber (Cucumber spp.), onion ... Cucumber (Cucumis sativus), Okra (Hibiscus esculentus), Radish (Rapanus sativus), Beetroot (Beta vulgaris), Carrot (Daucus carota), Avocado (Percy americana), Annona squamosa, Cainites (Chrysophyllum cainites), Canistellus (Pouteria campetiana), Cherry (Malpighia punicifolia), Custard apple (Annona reticulata), Plum (Spondia dulcis), Coconut (Cocos nucifera), Papaya (Carica Papaya, soursop (Annona muricata), guava (Psidium guajava), pomegranate (Punica granatum), lime (Citrus aurantifolia), lemon (Citrus limonum), red mamey (Callocarpum mammosum), mamey Santo Domingo (Mamella americana), Melicocca tree (Melicocea bijuga), mandarin (Citrus reticulata), mango (Mangifera indica), passion fruit (Passiflora laurifolia), watermelon (Citrus vulgaris), bitter orange (Citrus aurantium), sweet orange (Citrus sinensis), pineapple (Ananas comosus), banana (Musa paradisiaca), plantain (Musa balbisciana), tamarind (Tamarindus indica), grapefruit (Citrus paradisi), creole grapefruit (Citrus grandis), grape (Vitis vinifera), corn (Zea mays), rice (Oryza sativa), coffee (Coffea arabica), sugarcane (Saccharum officinarum), cotton (Gossypium hirsutum),4. The use according to claim 3, wherein the plant is selected from the group consisting of gherkin (Meloteria guadalupensis), sweet potato (Ipomoes batatas), potato (Solanum tuberosum), Creole potato (Solanum pleja), Cape gooseberry (Physalis peruviana), cassava (Manihot esculenta), soybean (Glycine max), strawberry (Fragaria spp.), blackberry (Morus spp.), raspberry (Rubus spp.), palm of the Aracaceae family, oil palm (Elaeis guinensis), cocoa (Theobroma cacao), tomato plant (Solanum betaceum), and lulo (Solanum chitoense).

5. 4. The use according to claim 3, wherein the fungus is selected from the group comprising Magnaporthe oryzae, Botrytis cinerea, Puccinia spp. (including but not limited to Fusarium graminearum, Fusarium oxysporum), Blumeria graminis, Mycosphaerella spp., Mycosphaerella fiziensis, Mycosphaerella graminicola, Colletotrichum spp., Ustilago maydis, Melampsora lini, Phakopsora pachyrhizi, and Rhizoctonia solani.

6. 4. The use according to claim 3, wherein the oomycete is selected from the group comprising Phytophthora species, Phytophthora infestans, Phytophthora ramorum, Phytophthora soja, Phytophthora capsici, Phytophthora cinnamomi, Phytophthora palmivora, and Phytophthora paragitica, Hyaloperonospora arabidopsis, Plasmopara viticola, Pythium ultimum, Albugo candida, and Peronospora farinosa.

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