Pesticide suspension concentrate as well as preparation method and application thereof

Abstract

The invention relates to a pesticide water suspending agent as well as a preparation method and application thereof. The pesticide suspension concentrate contains nanoparticles obtained by supermolecule self-assembly of tea saponin and a hydrophobic pesticide, the average particle size of the nanoparticles is 40 nm to 150 nm, the polydispersity index of the nanoparticles is 0.05 to 0.37, and the absolute value of the surface potential of the nanoparticles is greater than 30 mV. The pesticide water suspending agent has the characteristics of small particle size, uniform particle size distribution, high dispersion stability and good slow release effect, can accurately act on a target, effectively improves the utilization rate and biological activity of a pesticide, and has high pesticide effect stability and strong durability, thereby remarkably improving the prevention and treatment effect of plant diseases and insect pests.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide preparations, in particular to a pesticide aqueous suspension concentrate and a preparation method and application thereof. Background Art

[0002] Pesticides play a vital role in agricultural production, helping to protect crops from pests and diseases and improving crop yield and quality. However, pesticide application often results in low utilization rates due to issues such as drift, volatilization, leaf drop, leaching, and photolysis. These issues prevent pesticides from effectively reaching their target, reducing their effectiveness and potentially causing unnecessary pollution and harm to the environment and ecosystems. Therefore, improving formulation technologies to increase pesticide utilization has become a research hotspot.

[0003] Aqueous suspension concentrates (ASs) are environmentally friendly, water-based pesticide formulations. They consist of a water-insoluble or slightly soluble solid pesticide, uniformly dispersed in water through wet ultrafine grinding with the aid of certain adjuvants. The result is a highly suspendable, flowable, and stable liquid-solid formulation with very fine particles. AASs stand out among water-based formulations due to their excellent environmental compatibility, high efficacy, low cost, and safe processing and use, demonstrating their significant potential for development.

[0004] However, the particle size of existing pesticide suspension concentrates is generally 1μm to 5μm. The large particle size can easily cause droplets to roll and dust to drift, resulting in the inability to accurately enter the target to exert its efficacy during use, and low biological activity and target utilization. At the same time, the particle size distribution is uneven and the storage stability is poor, resulting in poor efficacy and stability, thereby affecting the effect of plant disease and pest control. Summary of the Invention

[0005] Therefore, it is necessary to provide a pesticide aqueous suspension concentrate, its preparation method, and its application to address the above-mentioned problems. This pesticide aqueous suspension concentrate has the characteristics of small particle size, uniform particle size distribution, high dispersion stability, and good sustained-release effect. It can precisely act on the target, effectively improving the utilization rate and biological activity of the pesticide. At the same time, it has high efficacy stability and long-lasting effect, thereby significantly improving the control effect of plant diseases and insect pests.

[0006] A pesticide aqueous suspension concentrate contains nanoparticles obtained by supramolecular self-assembly of tea saponin and a hydrophobic pesticide, wherein the nanoparticles have an average particle size of 40 nm to 150 nm, a polydispersity index of 0.05 to 0.37, and an absolute value of a surface potential greater than 30 mV.

[0007] In one embodiment, the mass fraction of the nanoparticles in the pesticide aqueous suspension concentrate is 4.05%-17.43%.

[0008] In one embodiment, the mass ratio of the tea saponin to the hydrophobic pesticide is 1.06:1-3.24:1.

[0009] In one embodiment, the hydrophobic pesticide is selected from at least one of chlorpyrifos, flucythrin, prochloraz, triadimefon, difenoconazole, and flusilazole.

[0010] The pesticide aqueous suspension concentrate of the present invention is obtained by supramolecular self-assembly of tea saponin and a hydrophobic pesticide through nanoparticles, and the average particle size, polydispersity index and absolute value of the surface potential of the nanoparticles are limited. Under this synergistic effect, the pesticide aqueous suspension concentrate has the characteristics of small particle size, uniform particle size distribution, high dispersion stability and good sustained-release effect, so that the pesticide aqueous suspension concentrate can accurately act on the target, effectively improving the utilization rate and biological activity of the pesticide, while having high efficacy stability and long-lasting efficacy, thereby significantly improving the control effect of plant diseases and insect pests.

[0011] A method for preparing the pesticide aqueous suspension concentrate comprises the following steps:

[0012] mixing a hydrophobic pesticide and a tea saponin extract to obtain a mixed solution, wherein the mass ratio of the hydrophobic pesticide to the tea saponin extract is 1:99-1:9;

[0013] Under stirring, the mixed liquid is heated and then cooled to form nanoparticles to obtain a pesticide aqueous suspension concentrate, wherein the stirring speed is 200 rpm-800 rpm, the heating treatment temperature is T1, the melting point temperature of the hydrophobic pesticide is T2, T2<T1<T2+20°C, and the cooling temperature is T3, T3<T2.

[0014] In one embodiment, the melting point temperature T2 of the hydrophobic pesticide is lower than 100°C.

[0015] In one embodiment, the mass fraction of tea saponin in the tea saponin extract is 10%-20%.

[0016] In one embodiment, the heating time is 2h-10h;

[0017] And / or, the cooling temperature T3 is room temperature, and the cooling time is 2h-5h.

[0018] In one embodiment, the method for preparing the pesticide aqueous suspension further includes the following steps: after cooling to form nanoparticles, an auxiliary agent is added and mixed to obtain the pesticide aqueous suspension, wherein the auxiliary agent is selected from at least one of an antifreeze agent and a thickener.

[0019] The method for preparing a pesticide aqueous suspension concentrate of the present invention uses tea saponin in a tea saponin extract as a carrier and adopts supramolecular self-assembly technology to enable hydrophobic pesticide molecules to be precisely guided to the surface or interior of a nano-micelle carrier formed by the tea saponin. At the same time, by limiting the mass ratio of the hydrophobic pesticide to the tea saponin extract, controlling the stirring speed and the relationship between the heating temperature T1, the cooling temperature T3 and the melting point temperature T2 of the hydrophobic pesticide, nanoparticles with a specific particle size, polydispersity index and surface potential are formed, thereby obtaining a pesticide aqueous suspension concentrate with a small particle size, uniform particle size distribution and high dispersion stability. The preparation method is simple, does not require the addition of organic solvents or catalysts during the preparation process, and is low in cost.

[0020] An application of the pesticide aqueous suspension concentrate in preventing and controlling plant diseases and insect pests. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a transmission electron micrograph of the pesticide aqueous suspension concentrate prepared in Example 4 of the present invention;

[0023] Figure 2 This is a scanning electron microscope image of the pesticide aqueous suspension prepared in Example 4 of the present invention;

[0024] Figure 3 This is a graph of wheat chlorophyll content comparing the safety of the 12% tea saponin extract, the pesticide suspension concentrate, and the commercially available 20% triadimefon emulsifiable concentrate prepared in Example 4 of the present invention to wheat. In the graph, A represents the control group, B represents the 12% tea saponin extract prepared in Example 4, C represents the pesticide suspension concentrate prepared in Example 4, and D represents the commercially available 20% triadimefon emulsifiable concentrate. a represents that there is no significant difference between the treatments at the 0.05 level. Each treatment was replicated three times, and the data are expressed as mean ± standard deviation.

[0025] Figure 4This is a wheat plant height graph showing the safety of the 12% tea saponin extract, the pesticide suspension concentrate, and the commercially available 20% triadimefon emulsifiable concentrate prepared in Example 4 of the present invention. In the graph, A represents the control group, B represents the 12% tea saponin extract prepared in Example 4, C represents the pesticide suspension concentrate prepared in Example 4, and D represents the commercially available 20% triadimefon emulsifiable concentrate. a represents that there is no significant difference between the treatments at the 0.05 level. Each treatment was replicated three times, and the data are expressed as mean ± standard deviation.

[0026] Figure 5 This is a wheat fresh weight graph showing the safety of the 12% tea saponin extract, the pesticide aqueous suspension concentrate, and the commercially available 20% triadimefon emulsifiable concentrate prepared in Example 4 of the present invention. In the graph, A represents the control group, B represents the 12% tea saponin extract prepared in Example 4, C represents the pesticide aqueous suspension concentrate prepared in Example 4, and D represents the commercially available 20% triadimefon emulsifiable concentrate. a, b, and c all represent significant differences between the treatments at the 0.05 level. Each treatment was replicated three times, and the data are expressed as mean ± standard deviation.

[0027] Figure 6 This is a contact angle comparison diagram of the pesticide suspension concentrate prepared in Example 4 of the present invention, deionized water (CK), and a commercially available 20% triadimefon emulsifiable concentrate formulation, wherein in the figure, A represents a control group, B represents a commercially available 20% triadimefon emulsifiable concentrate formulation, and C represents the pesticide suspension concentrate prepared in Example 4;

[0028] Figure 7 This is a particle size distribution diagram of nanoparticles in the pesticide aqueous suspension prepared in Example 4 of the present invention;

[0029] Figure 8 This is a comparative graph showing the indoor toxicity test on wheat scab of the 12% tea saponin extract, the pesticide aqueous suspension prepared in Example 4 of the present invention, and a commercially available 20% triadimefon emulsifiable concentrate. In the figure, A represents the pesticide aqueous suspension prepared in Example 4, B represents the commercially available 20% triadimefon emulsifiable concentrate, and C represents the 12% tea saponin extract prepared in Example 4.

[0030] Figure 9 This is a comparative graph showing the indoor toxicity test on wheat powdery mildew of the 12% tea saponin extract, the pesticide aqueous suspension prepared in Example 4 of the present invention, and a commercially available 20% triadimefon emulsifiable concentrate. In the figure, A represents the pesticide aqueous suspension prepared in Example 4, B represents the commercially available 20% triadimefon emulsifiable concentrate, and C represents the 12% tea saponin extract prepared in Example 4.

[0031] Figure 10This is a comparison chart of the zeta potential of the pesticide aqueous suspension concentrate prepared in Example 4 of the present invention and the tea saponin extract, wherein in the figure, A represents the 12% concentration tea saponin extract prepared in Example 4, and B represents the pesticide aqueous suspension concentrate prepared in Example 4;

[0032] Figure 11 This is a graph showing the release behavior of triadimefon from the pesticide aqueous suspension concentrate prepared in Example 4 of the present invention at a pH of 5;

[0033] Figure 12 This is a graph showing the release behavior of triadimefon from the pesticide aqueous suspension concentrate prepared in Example 4 of the present invention at a pH of 7;

[0034] Figure 13 This is a graph showing the release behavior of triadimefon from the pesticide aqueous suspension concentrate prepared in Example 4 of the present invention at a pH of 9;

[0035] Figure 14 This is a graph showing the particle size change of the pesticide aqueous suspension prepared in Example 4 of the present invention after hot storage (54° C.) for 14 days;

[0036] Figure 15 This is a graph showing the particle size change of the pesticide aqueous suspension prepared in Example 4 of the present invention after cold storage (0° C.) for 14 days. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments or embodiments and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, including any two related listed items, any more related listed items, or the combination of all related listed items.

[0039] Supramolecular self-assembly technology is a technique that uses non-covalent bonding to enable molecules to spontaneously organize into ordered structures. In the pesticide field, supramolecular self-assembly can form ordered structures in solid or solution states, thereby enhancing the pesticide's stability, solubility, dissolution properties, and biological properties. Furthermore, supramolecular self-assembly can increase the adhesion of pesticide droplets to plant leaves, facilitating their efficient absorption and reducing their environmental residues.

[0040] At the same time, tea saponin is a kind of pure natural nonionic surfactant, and there are hydrophilic sugar body and hydrophobic ligand group in the molecule. Therefore, it has multiple surface activities such as emulsification, dispersion, wetting, decontamination, foaming, foam stabilization, especially has very strong foaming ability, and the foam produced is stable and is not affected by water hardness. However, the applicant has found through in-depth research that in the field of pesticides, tea saponin most of them are used as pesticide adjuvants (such as, surfactant, emulsifier or synergist etc.), directly as biopesticides (such as, as insecticide, bactericide or acaricide) or with isocyanate reaction to prepare capsule wall for the preparation of microcapsules, but there is no related report on the formation of nanoparticles by supramolecular self-assembly with hydrophobic pesticides using tea saponin as a carrier, and obtaining agricultural pesticide aqueous suspension concentrates.

[0041] To this end, the present invention provides a pesticide aqueous suspension concentrate, which contains nanoparticles obtained by supramolecular self-assembly of tea saponin and a hydrophobic pesticide, wherein the nanoparticles have an average particle size of 40nm-150nm, a polydispersity index of 0.05-0.37, and an absolute value of a surface potential greater than 30mV.

[0042] In the present invention, the nanoparticles contained in the pesticide suspension concentrate are formed by supramolecular self-assembly with the hydrophobic pesticide using tea saponin as a carrier. It can be understood that the nanoparticles use the nanomicelle carriers formed by molecular self-assembly of tea saponin to encapsulate the hydrophobic pesticide. These nanoparticles can significantly increase the effective loading capacity of the pesticide suspension concentrate for the hydrophobic pesticide, greatly enhancing the stability and bioavailability of the hydrophobic pesticide in the environment, effectively solving traditional problems such as pesticide drift, volatilization, and leaf roll-off. At the same time, they impart a good sustained-release effect to the pesticide suspension concentrate, ensuring the long-lasting efficacy of the drug. Furthermore, tea saponin has insecticidal and antibacterial activity and, as a carrier, can synergize with chemical pesticides to control plant diseases and insect pests. Specifically, the pesticide suspension concentrate has a drug loading of 23.60%-48.53% and an encapsulation efficiency of 79%-96%.

[0043] At the same time, by limiting the average particle size of nanoparticles, the pesticide suspension concentrate has a larger specific surface area, which increases the contact area between the pesticide and the crop surface, and increases the adhesion and permeability of the pesticide on the crop leaves, which is conducive to the pesticide acting on the target more accurately and entering the micro-nano structure of the crop leaves, thereby enhancing the effective amount of the drug on the crop leaves, thereby improving the effective utilization rate and biological activity of the pesticide and reducing the number and amount of application.

[0044] In addition, by limiting the polydispersity index and absolute value of the surface potential of the nanoparticles, the particle size of the pesticide suspension can be made uniform and the dispersion stability is high, thereby improving the efficacy stability of the pesticide, further improving the biological activity of the pesticide and the average particle size of the synergistic nanoparticles, which is conducive to more precise regulation of the sustained release rate of the pesticide, further improving the durability of the efficacy, and thus better improving the prevention and control effect of plant diseases and pests.

[0045] Therefore, the pesticide aqueous suspension concentrate of the present invention is obtained by supramolecular self-assembly of tea saponin and a hydrophobic pesticide through nanoparticles, and the average particle size, polydispersity index and absolute value of the surface potential of the nanoparticles are limited. Under this synergistic effect, the pesticide aqueous suspension concentrate has the characteristics of small particle size, uniform particle size distribution, high dispersion stability and good sustained release effect, so that it can act on the target accurately, effectively improve the utilization rate and biological activity of the pesticide, and at the same time, the efficacy is highly stable and the efficacy is long-lasting, thereby significantly improving the control effect of plant diseases and insect pests.

[0046] In addition, the pesticide aqueous suspension concentrate still has high physical stability without the addition of dispersants or thickeners, which can effectively reduce the use of reagent raw materials and lower production costs.

[0047] Optionally, the mass fraction of the nanoparticles in the pesticide suspension concentrate is 4.05%-17.43%. Specifically, the mass fraction of the nanoparticles in the pesticide suspension concentrate includes, but is not limited to, 4.05%, 9.08%, 11.44%, 11.70%, 12.58%, 12.98%, 13.84%, 14.48%, 16.69%, 17.43%, etc. By adjusting the mass fraction of the nanoparticles, the control effect of the pesticide suspension concentrate on plant diseases and insect pests can be further improved.

[0048] Optionally, the mass ratio of the tea saponin to the hydrophobic pesticide is 1.06:1-3.24:1. Specifically, the mass ratio of the tea saponin to the hydrophobic pesticide includes but is not limited to 1.06:1, 1.08:1, 1.30:1, 1.35:1, 1.83:1, 2.05:1, 2.18:1, 2.19:1, 2.21:1, 2.75:1, 3.22:1, 3.24:1, etc. In this way, by adjusting the mass of the tea saponin and the hydrophobic pesticide, the morphology and size of the nanoparticles are regulated, which is conducive to obtaining nanoparticles with high drug loading and high encapsulation efficiency, thereby improving the sustained release effect of the pesticide suspension concentrate and the bioavailability and biological activity of the pesticide.

[0049] Optionally, the hydrophobic pesticide is selected from at least one of chlorpyrifos, cypermethrin, prochloraz, triadimefon, difenoconazole, and flusilazole.

[0050] At the same time, the present invention also provides a method for preparing the pesticide aqueous suspension concentrate, comprising the following steps:

[0051] S1, mixing a hydrophobic pesticide and a tea saponin extract to obtain a mixed solution, wherein the mass ratio of the hydrophobic pesticide to the tea saponin extract is 1:9-1:99. It can be understood that controlling the mass ratio of the hydrophobic pesticide to the tea saponin extract in step S1 facilitates the formation of nanoparticles in the subsequent step S2, which are formed by supramolecular self-assembly of the hydrophobic pesticide and the tea saponin as a carrier.

[0052] In step S1, the melting point temperature T2 of the hydrophobic pesticide is less than 100°C. Furthermore, the hydrophobic pesticide is selected from at least one of chlorpyrifos, cypermethrin, prochloraz, triadimefon, difenoconazole, and flusilazole. This configuration facilitates the formation of nanoparticles encapsulating the hydrophobic pesticide under mild conditions in the presence of a tea saponin extract.

[0053] Optionally, the mass fraction of tea saponin in the tea saponin extract is 10%-20%. By controlling the mass fraction of tea saponin in the tea saponin extract, this configuration facilitates better formation of a self-assembled structure in the subsequent step S2. That is, the nano-micelle carriers formed by self-assembly of tea saponin promote better embedding of the hydrophobic pesticide in the tea saponin carriers, thereby obtaining nanoparticles having a mass ratio of tea saponin to the hydrophobic pesticide of 1.06:1-3.24:1.

[0054] In the present invention, the preparation method of the tea saponin extract is not particularly limited. In one embodiment, it can be prepared by water extraction or organic solvent extraction, preferably water extraction. This arrangement ensures that the solvent of the pesticide suspension concentrate is only water, without any organic solvent, thereby avoiding environmental pollution caused by organic solvents and promoting environmental protection. It also increases the drug loading capacity of the pesticide suspension concentrate.

[0055] Specifically, the method for preparing the tea saponin extract comprises the following steps: mixing tea seed cake and water, heating and stirring, filtering, retaining the filter residue, repeating the extraction at least twice, and combining the filtrates to obtain the tea saponin extract, wherein the mass ratio of the tea seed cake to water is 1:4-1:9, and the heating temperature T1 is 50°C-85°C. This configuration facilitates obtaining a tea saponin mass fraction of 10%-20% in the tea saponin extract.

[0056] Optionally, the tea seed cake is waste product from the extraction of oil from at least one of the seeds of tea, Theaceae plants, and Theaceae plants. Thus, the preparation method utilizes tea seed cake, an agricultural waste, as a raw material, not only reducing environmental pollution caused by waste accumulation but also promoting the recycling of agricultural resources, injecting new vitality into the sustainable development of modern agriculture.

[0057] S2. While stirring, the mixed liquid is heated and then cooled to form nanoparticles to obtain a pesticide suspension concentrate, wherein the stirring speed is 200 rpm-800 rpm, the heating temperature is T1, the melting point of the hydrophobic pesticide is T2, T2<T1<T2+20°C, and the cooling temperature is T3, T3<T2.

[0058] In step S2, under a stirring state at a stirring speed of 200 rpm-800 rpm, when T2 is less than T1, the hydrophobic pesticide will melt and be completely converted from a solid phase into a hydrophobic oily liquid; at the same time, tea saponin will reach a critical micelle concentration and self-assemble to form nano micelles. At this time, tea saponin has a solubilizing effect, and the formed hydrophobic oily liquid is continuously solubilized in the hydrophobic core of the micelles formed by tea saponin under the solubilizing effect of tea saponin, forming a thermodynamically stable homogeneous system; then the homogeneous system is cooled, and T3 is less than T2. ​​As the temperature of the homogeneous system gradually decreases, the hydrophobic oily liquid solidifies to form nanoparticles composed of tea saponin and hydrophobic pesticide through supramolecular self-assembly, and finally a pesticide aqueous suspension concentrate is obtained, wherein the average particle size of the nanoparticles is 40 nm-150 nm, the polydispersity index is 0.05-0.37, and the absolute value of the surface potential is greater than 30 mV.

[0059] It is understood that in step S2, both the heating and cooling are carried out under stirring. Simultaneously, in the step of heating the mixed solution, the heating temperature T1 is controlled so that the hydrophobic pesticide is converted from a solid phase to a liquid phase, and the tea saponin reaches a critical micelle concentration and self-assembles to form nanomicelles. Furthermore, in the step of cooling to form nanoparticles, the cooling temperature T3 is controlled so that the liquid hydrophobic pesticide is again converted from a liquid phase to a solid phase to form nanoparticles. Therefore, in the method for preparing the pesticide aqueous suspension concentrate of the present invention, the hydrophobic pesticide undergoes two phase transitions and self-assembles with the tea saponin to form nanoparticles. This method is green, environmentally friendly, and simple.

[0060] Optionally, the heating treatment time is 2h-10h; such setting is conducive to solubilizing more of the hydrophobic oily liquid in the hydrophobic core of the micelles formed by tea saponin, further improving the encapsulation efficiency and drug loading of the pesticide aqueous suspension concentrate.

[0061] It will be appreciated that the cooling temperature T3 in the present invention is less than the melting point T2 of the hydrophobic pesticide in order to convert the hydrophobic oily liquid into a solid phase of the hydrophobic pesticide. Preferably, the cooling temperature T3 is room temperature, and the cooling time is 2-5 hours. This configuration simplifies the process and facilitates the production of nanoparticles that are entirely solid.

[0062] In the present invention, in step S2, after cooling to form nanoparticles, an auxiliary agent is added and mixed to obtain an aqueous pesticide suspension concentrate, wherein the auxiliary agent is selected from at least one of an antifreeze agent and a thickener, wherein the antifreeze agent is preferably propylene glycol, and the thickener is preferably xanthan gum. This configuration allows the aqueous pesticide suspension concentrate to have an anti-freeze effect and anti-settling ability, further improving the performance stability of the aqueous pesticide suspension concentrate.

[0063] In one embodiment, the mass ratio of the adjuvant to the hydrophobic pesticide is 1:25-1:1.

[0064] Therefore, the preparation method of the pesticide aqueous suspension concentrate of the present invention uses tea saponin in the tea saponin extract as a carrier and adopts supramolecular self-assembly technology, so that hydrophobic pesticide molecules can be accurately guided to the surface or interior of the nano-micelle carrier formed by the tea saponin. At the same time, by limiting the mass ratio of the hydrophobic pesticide and the tea saponin extract, controlling the stirring speed and the relationship between the heating treatment temperature T1, the cooling temperature T3 and the melting point temperature T2 of the hydrophobic pesticide, nanoparticles with a specific particle size, polydispersity index and surface potential are formed, thereby obtaining a pesticide aqueous suspension concentrate with a small particle size, uniform particle size distribution and high dispersion stability. At the same time, the preparation method is simple, and no dispersant or thickener is required in the preparation process, so the cost is low.

[0065] In addition, the present invention also provides an application of the pesticide aqueous suspension concentrate in preventing and controlling plant diseases and insect pests.

[0066] Specifically, in one embodiment, when triadimefon is the hydrophobic pesticide in the aqueous suspension concentrate, it can effectively control wheat head blight and wheat powdery mildew, and the control effect is superior to commercially available triadimefon emulsifiable concentrate formulations. Moreover, the aqueous suspension concentrate does not contain organic solvents, has low damage to crops, and is more environmentally friendly.

[0067] The following specific examples will further illustrate the pesticide aqueous suspension concentrate, its preparation method, and its application. However, it will be understood by those skilled in the art that the following examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the present invention. In the examples, where specific conditions are not specified, the procedures were performed according to conventional conditions or manufacturer recommendations. Reagents or instruments used where the manufacturer is not specified are commercially available conventional products.

[0068] Example 1

[0069] Mix tea seed cake and water in a mass ratio of 1:9, heat at 80° C., stir for 2 hours, filter, retain the filter residue, repeat the extraction three times, combine the filtrate, and obtain a tea saponin extract, wherein the concentration of the tea saponin extract is 12%.

[0070] 5 g of chlorpyrifos (melting point temperature of approximately 43° C.) and 95 g of the tea saponin extract obtained above were mixed to obtain a mixed solution. The mixed solution was then treated at 50° C. at a rotation speed of 400 rpm for 8 hours to completely convert the solid chlorpyrifos into a liquid phase and self-assemble with the tea saponin in the extract. The mixture was then treated at room temperature for 3 hours to convert the liquid chlorpyrifos in the self-assembly into a solid phase and form nanoparticles, thereby obtaining an aqueous pesticide suspension concentrate. The mass fraction of the nanoparticles in the aqueous pesticide suspension concentrate was 12.58%, the average particle size of the nanoparticles was approximately 84.41 nm, the polydispersity index was 0.12, the encapsulation efficiency was 89%, the drug loading was 35.37%, and the absolute value of the surface potential was 35.62 mV.

[0071] Example 2

[0072] Example 2 differs from Example 1 only in that 4 g of cypermethrin (melting point temperature 60° C.) and 96 g of tea saponin extract are mixed to obtain a mixed solution; the mixed solution is treated at 65° C. at a rotation speed of 800 rpm for 6 hours, so that the solid phase of cypermethrin is completely converted into a liquid phase and self-assembles with the tea saponin in the extract. Then, the mixture is treated at room temperature for 5 hours, so that the liquid phase of cypermethrin in the self-assembly is converted into a solid phase and forms nanoparticles, thereby obtaining a pesticide suspension concentrate. The mass fraction of the nanoparticles in the pesticide suspension concentrate is 11.70%, the average particle size of the nanoparticles is approximately 59.83 nm, the polydispersity index is 0.07, the encapsulation efficiency is 92%, the drug loading is 31.45%, and the absolute value of the surface potential is 33.08 mV.

[0073] Example 3

[0074] Example 3 differs from Example 1 only in that 10 g of prochloraz (melting point temperature: 46.5° C.) and 90 g of tea saponin extract are mixed to obtain a mixed solution; the mixed solution is treated at 65° C. at a rotation speed of 600 rpm for 7 hours, so that the solid phase of prochloraz is completely converted into a liquid phase and self-assembles with the tea saponin in the extract. The mixture is then treated at room temperature for 3 hours, so that the liquid phase of prochloraz in the self-assembly is converted into a solid phase and forms nanoparticles, thereby obtaining an aqueous pesticide suspension concentrate. The mass fraction of the nanoparticles in the aqueous pesticide suspension concentrate is 16.69%, the average particle size of the nanoparticles is approximately 121.47 nm, the polydispersity index is 0.2, the encapsulation efficiency is 81%, the drug loading is 48.53%, and the absolute value of the surface potential is 30.85 mV.

[0075] Example 4

[0076] Example 4 differs from Example 1 only in that 1 g of triadimefon (melting point temperature: 82° C.) and 99 g of tea saponin extract are mixed to obtain a mixed solution; the mixed solution is treated at 85° C. at a rotation speed of 400 rpm for 6 hours, so that the solid phase of triadimefon is completely converted into a liquid phase and self-assembles with the tea saponin in the extract. The mixture is then treated at room temperature for 2 hours, so that the liquid phase of triadimefon in the self-assembly is converted into a solid phase and forms nanoparticles, thereby obtaining a pesticide suspension concentrate. The mass fraction of the nanoparticles in the pesticide suspension concentrate is 4.05%, the average particle size of the nanoparticles is approximately 44.23 nm, the polydispersity index is 0.133, the encapsulation efficiency is 96%, the drug loading is 23.70%, and the absolute value of the surface potential is 31.02 mV.

[0077] from Figure 1-2 It can be seen that the pesticide aqueous suspension prepared in this example contains nanoparticles, which are spherical and have uniform particle size distribution.

[0078] Example 5

[0079] Example 5 differs from Example 1 only in that 3 g of difenoconazole (melting point temperature: 76° C.) and 97 g of tea saponin extract are mixed to obtain a mixed solution; the mixed solution is treated at 85° C. at a rotation speed of 200 rpm for 9 hours, so that the solid phase of difenoconazole is completely converted into a liquid phase and self-assembles with the tea saponin in the extract. The mixture is then treated at room temperature for 5 hours, so that the liquid phase of difenoconazole in the self-assembly is converted into a solid phase and forms nanoparticles, thereby obtaining a pesticide suspension concentrate. The mass fraction of the nanoparticles in the pesticide suspension concentrate is 11.44%, the average particle size of the nanoparticles is about 51.07 nm, the polydispersity index is 0.05, the encapsulation efficiency is 90%, the drug loading is 23.60%, and the absolute value of the surface potential is 34.84 mV.

[0080] Example 6

[0081] Example 6 differs from Example 1 only in that 7 g of flusilazole (melting point temperature of 53° C.) and 93 g of tea saponin extract are mixed to obtain a mixed solution; the mixed solution is treated at 60° C. at a rotation speed of 400 rpm for 7 hours, so that the solid phase flusilazole is completely converted into a liquid phase and self-assembles with the tea saponin in the extract. Then, the mixture is treated at room temperature for 2 hours, so that the liquid phase flusilazole in the self-assembly is converted into a solid phase and forms nanoparticles, thereby obtaining a pesticide suspension concentrate. The mass fraction of the nanoparticles in the pesticide suspension concentrate is 14.48%, the average particle size of the nanoparticles is about 101.28 nm, the polydispersity index is 0.16, the encapsulation efficiency is 88%, the drug loading is 42.54%, and the absolute value of the surface potential is 32.17 mV.

[0082] Example 7

[0083] Example 7 is different from Example 1 only in that tea seed cake and water are mixed in a mass ratio of 1:4, heated at 90°C, stirred for 3 hours, filtered, the filter residue is retained, the extraction is repeated 3 times, and the filtrate is combined to obtain a tea saponin extract, wherein the concentration of the tea saponin extract is 20%; the other conditions are the same, and a pesticide suspension concentrate is obtained, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 17.43%, the average particle size of the nanoparticles is about 71.47 nm, the polydispersity index is 0.09, the encapsulation efficiency is 93%, the drug loading is 26.68%, and the absolute value of the surface potential is 36.19 mV.

[0084] Example 8

[0085] Example 8 is different from Example 1 only in that tea seed cake and water are mixed in a mass ratio of 1:8, heated at 80°C, stirred for 2 h, filtered, the filter residue is retained, the extraction is repeated twice, and the filtrates are combined to obtain a tea saponin extract, wherein the concentration of the tea saponin extract is 10%; the other conditions are the same, and a pesticide suspension concentrate is obtained, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 12.98%, the average particle size of the nanoparticles is about 76.19 nm, the polydispersity index is 0.11, the encapsulation efficiency is 85%, the drug loading is 32.74%, and the absolute value of the surface potential is 34.11 mV.

[0086] Example 9

[0087] Example 9 is different from Example 1 only in that tea seed cake and water are mixed in a mass ratio of 1:9, heated at 70°C, stirred for 2 hours, filtered, the filter residue is retained, the extraction is repeated 3 times, and the filtrate is combined to obtain a tea saponin extract, wherein the concentration of the tea saponin extract is 8%; the other conditions are the same, and a pesticide suspension concentrate is obtained, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 9.12%, the average particle size of the nanoparticles is about 137 nm, the polydispersity index is 0.32, the encapsulation efficiency is 76%, the drug loading capacity is 41.67%, and the absolute value of the surface potential is 30.82 mV.

[0088] Example 10

[0089] Example 10 differs from Example 1 only in that the treatment is performed at room temperature for 3 hours to convert the liquid phase of chlorpyrifos into a solid phase and form nanoparticles, and then 5 g of propylene glycol is added and mixed to obtain an aqueous pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the aqueous pesticide suspension concentrate is 13.84%, the average particle size of the nanoparticles is about 74.42 nm, the polydispersity index is 0.11, the encapsulation efficiency is 91%, the drug loading is 31.31%, and the absolute value of the surface potential is 40.18 mV.

[0090] Example 11

[0091] Example 11 differs from Example 1 only in that the chlorpyrifos in the liquid phase is treated at room temperature for 3 hours to convert the solid phase and form nanoparticles, and then 0.2 g of xanthan gum is added and mixed to obtain an aqueous pesticide suspension concentrate. The mass fraction of the nanoparticles in the aqueous pesticide suspension concentrate is 14.11%, the average particle size of the nanoparticles is approximately 77.90 nm, the polydispersity index is 0.12, the encapsulation efficiency is 88%, the drug loading is 31.12%, and the absolute value of the surface potential is 37.64 mV.

[0092] Comparative Example 1

[0093] Comparative Example 1 is compared with Example 4, except that the mixed solution is treated at 40° C. for 5 h at a rotation speed of 400 rpm, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 0.61%, the average particle size of the nanoparticles is about 389.12 nm, the polydispersity index is 0.95, the encapsulation efficiency is 8%, the drug loading is 13.11%, and the absolute value of the surface potential is 2.71 mV.

[0094] After testing, it was found that the number of nanoparticles in the pesticide aqueous suspension concentrate of this comparative example was small and the sizes were uneven.

[0095] Comparative Example 2

[0096] Comparative Example 2 is different from Example 4 only in that 15 g of triadimefon (melting point temperature is 82 ° C.) and 85 g of tea saponin extract are mixed to obtain a mixed solution, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 13.67%, the average particle size of the nanoparticles is about 870.60 nm, the polydispersity index is 0.97, the encapsulation efficiency is 25.67%, the drug loading is 28.16%, and the absolute value of the surface potential is 10.05 mV.

[0097] Upon testing, it was found that the dosage of triadimefon in this comparative example was too high, resulting in failure to form nano-sized particles, and the triadimefon was not fully reacted, resulting in the presence of a large amount of triadimefon technical crystals in the pesticide aqueous suspension concentrate.

[0098] Comparative Example 3

[0099] Comparative Example 3 is different from Example 4 only in that 0.1 g of triadimefon (melting point temperature is 82 ° C.) and 99.9 g of tea saponin extract are mixed to obtain a mixed solution, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 0.41%, the average particle size of the nanoparticles is about 48.05 nm, the polydispersity index is 0.03, the encapsulation efficiency is 97%, the drug loading is 23.72%, and the absolute value of the surface potential is 11.72 mV.

[0100] Comparative Example 4

[0101] Comparative Example 4 is different from Example 4 only in that saponins and water are mixed in a mass ratio of 1:9, heated at 80° C., stirred for 2 h, filtered, the filter residue is retained, the extraction is repeated 3 times, and the filtrate is combined to obtain a saponin extract; the concentration of the saponin extract is 15%.

[0102] 1 g of triadimefon and 99 g of saponin extract were mixed to obtain a mixed solution, and other conditions were kept the same to obtain a pesticide aqueous suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide aqueous suspension concentrate was 0.91%, the average particle size of the nanoparticles was about 437.89 nm, the polydispersity index was 0.80, the encapsulation efficiency was 23%, the drug loading was 25.27%, and the absolute value of the surface potential was 9.66 mV.

[0103] After testing, it was found that in this comparative example, the number of nanoparticles formed was significantly reduced and crystallization occurred due to the use of saponin extract instead of tea saponin extract.

[0104] Comparative Example 5

[0105] Comparative Example 5 is different from Example 1 only in that the mixed solution is treated at 70°C for 3h, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 5.48%, the average particle size of the nanoparticles is about 113.26nm, the polydispersity index is 0.37, the encapsulation efficiency is 91%, the drug loading is 16.61%, and the absolute value of the surface potential is 22.79mV.

[0106] Comparative Example 6

[0107] Comparative Example 6 is different from Example 1 only in that the mixed solution is treated at a temperature of 63°C for 4h, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 4.91%, the average particle size of the nanoparticles is about 80nm, the polydispersity index is 0.12, the encapsulation efficiency is 93%, the drug loading is 18.94%, and the absolute value of the surface potential is 29.74mV.

[0108] Comparative Example 7

[0109] Comparative Example 7 is different from Example 1 only in that it is then treated at 43°C for 2h, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 4.71%, the average particle size of the nanoparticles is about 50.47nm, the polydispersity index is 0.09, the encapsulation efficiency is 94%, the drug loading is 19.96%, and the absolute value of the surface potential is 27.65mV.

[0110] Comparative Example 8

[0111] Comparative Example 8 is different from Example 4 only in that the mixed solution is treated at 85°C for 5 h at a rotation speed of 100 rpm, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 2.27%, the average particle size of the nanoparticles is about 272.01 nm, the polydispersity index is 0.49, the encapsulation efficiency is 53%, the drug loading is 23.35%, and the absolute value of the surface potential is 13.28 mV.

[0112] Comparative Example 9

[0113] Comparative Example 9 is different from Example 4 only in that the mixed solution is treated at 85 ° C. for 5 h at a rotation speed of 1000 rpm, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 4.67%, the average particle size of the nanoparticles is about 61.64 nm, the polydispersity index is 0.14, the encapsulation efficiency is 87%, the drug loading is 18.63%, and the absolute value of the surface potential is 25.07 mV.

[0114] Comparative Example 10

[0115] Comparative Example 10 is different from Example 4 only in that an equal mass of oxamexyl is used instead of triadimefon, and the other conditions are the same to obtain a pesticide suspension concentrate, wherein the mass fraction of the nanoparticles in the pesticide suspension concentrate is 0.63%, the average particle size of the nanoparticles is about 747.53 nm, the polydispersity index is 0.86, the encapsulation efficiency is 8%, the drug loading is 12.70%, and the absolute value of the surface potential is 7.53 mV.

[0116] The performance test was conducted using the pesticide aqueous suspension prepared in Example 4 as an example. The specific test method and test results are as follows:

[0117] 1. Safety Testing: Wheat seedlings were treated with the pesticides at the seedling stage, and seven days later, their plant height, fresh weight, and chlorophyll content were assessed. The pesticides were grouped as follows: a commercially available 20% triadimefon emulsifiable concentrate, the pesticide suspension prepared in Example 4, and a 5% tea saponin extract. A water treatment control group was also included.

[0118] from Figure 3-4 It can be seen that compared with the water control, the three groups of pesticide treatments had no significant effect on wheat plant height and fresh weight. After observation, the wheat leaves in the group treated with the commercially available 20% triadimefon emulsifiable concentrate showed slight yellowing, while the other two groups showed no obvious abnormalities. Figure 5 As can be seen from the figure, the commercially available 20% triadimefon emulsifiable concentrate formulation significantly reduces the chlorophyll content of wheat. This shows that the pesticide aqueous suspension concentrate of Example 4 of the present invention can improve the safety of triadimefon when applied to wheat seedlings.

[0119] 2. Contact Angle Test: The wetting properties of the test products on plant leaves were tested using a contact angle meter. A spray suspension was prepared by diluting the formulation with deionized water. The theoretical concentration of triadimefon in both the commercially available 20% triadimefon emulsifiable concentrate and the pesticide suspension concentrate prepared in Example 4 was 1 mg / mL. Deionized water was used as a blank control. The contact angle of the suspension on wheat leaves was measured using a contact angle meter to simulate its wetting properties on wheat leaves.

[0120] like Figure 6 As shown, at the same concentration, commercially available 20% triadimefon emulsifiable concentrate, the pesticide aqueous suspension concentrate of Example 4, and deionized water (CK, as a control group) were dropped onto wheat leaves, and a contact angle test was performed for 6 minutes. The results showed that the contact angle of the control group remained basically stable during the test. The final contact angle (CA) of the droplets of the commercially available 20% triadimefon emulsifiable concentrate formulation was 68.25°, while the final contact angle of the droplets of the pesticide aqueous suspension concentrate of Example 4 was 46.73°, a difference of 21.52°. The experimental results strongly demonstrate that the wetting performance of the pesticide aqueous suspension concentrate of Example 4 on wheat leaves is significantly better than that of the commercially available 20% triadimefon emulsifiable concentrate formulation.

[0121] 3. Particle Size Analysis: The particle size of the nanoparticles in the pesticide aqueous suspension concentrate of Example 4 was accurately measured using a laser particle size analyzer (Model: Mastersizer 3000, Origin: UK). Particle size is a key indicator for assessing the degree of particle aggregation, and its distribution characteristics are crucial for understanding the dispersion state of the particle system. Specifically, when the polydispersity index (PI) is less than 0.05, it indicates that the particle system is monodisperse, with all particles of highly uniform size; when the PI is between 0.05-0.08, the system is considered to be a statically monodisperse system; and when the PI is between 0.08-0.7, it is considered to be a moderately dispersed system.

[0122] The particle size distribution of the nanoparticles in the pesticide aqueous suspension of Example 4 is as follows: Figure 7 As shown, from Figure 7 As can be seen in the results, the particle size of the nanoparticles ranges from 15nm to 130nm and exhibits a normal distribution. Approximately 70% of the nanoparticles are distributed within the narrow range of 30nm to 80nm, with a PI of 0.133 and a normal distribution. The average particle size is 44.23nm. This result demonstrates that the nanoparticles in the pesticide suspension concentrate prepared through the optimization experiment have a highly uniform particle size distribution. This demonstrates that the process not only effectively promotes the self-assembly of tea saponin and triadimefon, but also effectively achieves the uniform encapsulation of triadimefon using tea saponin as a carrier, forming uniformly distributed nanoparticles.

[0123] 4. Biological Toxicity Test: The mycelial growth inhibition method was used to evaluate the indoor toxicity of the pesticide suspension concentrate of Example 4 against wheat scab and wheat powdery mildew. In the test against wheat scab, a commercially available 20% triadimefon emulsifiable concentrate, the pesticide suspension concentrate prepared in Example 4, and a 12% tea saponin extract were prepared to obtain test samples with concentrations of 80 μg / mL, 40 μg / mL, 20 μg / mL, 10 μg / mL, and 5 μg / mL, respectively. A blank control group treated with clean water was also set up for testing. The test results are shown in the figure below. Figure 8 As shown, the toxicity regression curve of the pesticide suspension concentrate of Example 4 is y=1.3746x+7.3027, R 2 =0.9936, y is the lethal value, i.e., lethality%, x is the dose (i.e., drug concentration), the 95% confidence interval is 12.2992-19.6004, and the half effective inhibitory concentration (EC 50 ) is 15.74 mg / L; while the toxicity regression curve of the commercially available 20% triadimefon emulsifiable concentrate preparation is y=1.2012x+6.7076, R 2 =0.9724, y is the lethal value, i.e., lethality%, x is the dose (i.e., drug concentration), the 95% confidence interval is 20.9746-37.5244, and the half effective inhibitory concentration (EC 50 ) is 27.34 mg / L. It can be seen that the EC of the pesticide suspension concentrate of Example 4 is 50 Significantly lower than the EC of commercial 20% triadimefon emulsifiable concentrate 50 .

[0124] In the test for wheat powdery mildew, the commercially available 20% triadimefon emulsifiable concentrate, the pesticide aqueous suspension prepared in Example 4, and the tea saponin extract (12%) were respectively prepared to obtain test samples with concentrations of 0.025 μg / mL, 0.05 μg / mL, 0.1 μg / mL, 0.2 μg / mL, 0.4 μg / mL, 0.8 μg / mL, and 1.6 μg / mL, and a water treatment was set as a blank control group for testing. The test results are shown in FIG. Figure 9 As shown, the toxicity regression curve of the pesticide suspension concentrate of Example 4 is y=1.0565x+5.9555, R 2 =0.9772, y is the lethal value, i.e., lethality%, x is the dose (i.e., drug concentration), the 95% confidence interval is 0.0907-0.1713, and the half effective inhibitory concentration EC 50 The toxicity regression curve of the commercially available 20% triadimefon emulsifiable concentrate preparation is y=1.2192x+5.5197, R 2 =0.9536, y is the lethal value, i.e., lethality%, x is the dose (i.e., drug concentration), the 95% confidence interval is 0.2045-0.4999, and the half effective inhibitory concentration EC50 is 0.3195 mg / L. It can be seen that the EC of the pesticide suspension concentrate of Example 4 is 50 It is also lower than the EC of the commercial 20% triadimefon emulsifiable concentrate formulation. 50 The above results show that the pesticide aqueous suspension concentrate of Example 4 has higher fungicidal activity than the commercially available 20% triadimefon emulsifiable concentrate.

[0125] 5. Dispersion stability test: Zeta potential is a key indicator for measuring the interaction force between particles, and its numerical value directly reflects the stability of the system. When the size of molecules or dispersed particles is small, the absolute value of the Zeta potential will increase accordingly, which means that the system has a strong anti-aggregation ability and can maintain a good dissolved or dispersed state. On the contrary, if the absolute value of the Zeta potential is small, the system is more likely to coagulate or aggregate, because the attraction between particles dominates at this time, resulting in the destruction of the dispersed state. Therefore, the Zeta potential is often used as a basis for evaluating the degree of particle aggregation. Generally speaking, when the potential value is greater than or equal to +30mV, or less than or equal to -30mV, the system is considered to be relatively stable.

[0126] Specifically, a certain amount of sample was dispersed in pure water to prepare a 100 mg / L solution, and the solution was added to a cuvette using a disposable plastic pipette. The cuvette was placed in the sample cell of a nanoparticle size and zeta potential analyzer (Nano-zs 90 Nanosizer, Malvern Instruments, UK) to measure its zeta potential. Figure 10 The middle is the Zeta potential diagram of tea saponin extract (12%) and the pesticide suspension concentrate of Example 4; Figure 10 As can be seen, the charge of the tea saponin extract is -18.61 mV, while the charge of the pesticide suspension concentrate of Example 4 is -31.02 mV. The absolute value of the zeta potential of the tea saponin extract is less than 30 mV, indicating weak dispersibility and poor colloidal dispersion stability. In contrast, the absolute value of the zeta potential of the pesticide suspension concentrate of Example 4 is greater than 30 mV, indicating strong dispersibility and excellent colloidal dispersion stability.

[0127] 6. Sustained-Release Effect Testing: The drug release mechanism of the pesticide suspension concentrate of Example 4 under different pH conditions was explored. First, phosphate buffer solutions with pH values ​​of 5, 7, and 9 were prepared. The suspension concentrate was then diluted with each of the phosphate buffer solutions at these different pH values. Next, 10 mL of each diluted suspension was added to a glass bottle pre-filled with 10 mL of ethyl acetate. Finally, the glass bottle was placed on a drum rotating at 30 rpm. During the experiment, 100 μL of the upper ethyl acetate solution was withdrawn from the glass bottle at intervals of 0.0083, 0.17, 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, and 8 hours, diluted 10-fold with methanol, and then filtered through a filter to serve as the test sample. After each sampling, an equal volume of fresh ethyl acetate was quickly added to the sample to maintain a constant solvent volume. These samples were then analyzed by high-performance liquid chromatography to determine the triadimefon concentration in the ethyl acetate at each time point, and the changes in triadimefon release were analyzed accordingly. The analysis conditions of the high performance liquid chromatography method are as follows: a C18 reverse phase column (250 mm × 4.6 mm, 5 μm) was used, the column temperature was set to 30°C, the mobile phase was methanol and water (80:20, v / v), and the flow rate was 1.0 mL / min. The injection volume was 20 μL, and the absorbance wavelength was 282 nm. The experiment was repeated three times. The cumulative release rate of triadimefon in the pesticide suspension concentrate was calculated using the following formula: Cumulative release rate (%) = M t / M z ×100%, where M t It indicates the total amount of triadimefon released from the pesticide suspension concentrate over time, while M z It represents the initial amount of triadimefon in the pesticide suspension concentrate.

[0128] Under different pH conditions, the cumulative release rate of triadimefon in the pesticide suspension concentrate of Example 4 changes with time as shown in FIG. Figure 11 、 Figure 12 as well as Figure 13 As shown. After an initial short, rapid release of 1 hour, the release rate of triadimefon from the pesticide suspension concentrate significantly decreased, demonstrating excellent sustained-release properties. After 8 hours of slow release, the cumulative release rates of triadimefon from the pesticide suspension concentrate at pH values ​​of 5, 7, and 9 reached 70.47%, 71.14%, and 68.05%, respectively. Afterwards, the release rate of the pesticide suspension concentrate gradually approached equilibrium. The experimental results demonstrate that the pesticide suspension concentrate of Example 4 has excellent sustained-release properties.

[0129] 7. Storage stability test: Hot and cold storage tests (stability tests) of pesticide formulations are important methods for evaluating the physical and chemical stability of products under extreme temperature conditions. Specifically, hot storage test: take 3 samples of the pesticide suspension concentrate of Example 4 and seal them in glass bottles; then place the samples in a constant temperature oven (54±2°C) and store them for 14 days, ensuring uniform temperature and avoiding light. Cold storage test: also take 3 samples of the pesticide suspension concentrate of Example 4 and seal them in glass bottles; then place the samples in a low-temperature refrigerator (0°C) to ensure stable temperature and store them for 14 days; during the hot storage test and the cold storage test, take one milliliter of sample every day for sample particle size analysis.

[0130] like Figure 14 and Figure 15 As shown, we conducted a systematic hot and cold storage stability evaluation of the pesticide suspension concentrate of Example 4. The hot storage test data showed that over the 14-day observation period, the particle size of the triadimefon nanoparticles exhibited a significant time-varying characteristic, gradually increasing from an initial size of approximately 40 nm to approximately 800 nm. This particle size growth phenomenon may be attributed to the intensified Brownian motion of the nanoparticles driven by thermodynamics, which led to an increase in the frequency of interparticle collisions and, in turn, an agglomeration effect. Notably, despite the significant particle size growth observed, the particle size remained within the nanoscale range (<1000 nm) throughout the test period, indicating that the formulation maintained good physical stability under high temperature conditions. In contrast, the cold storage test results showed that the triadimefon nanoparticles exhibited excellent dimensional stability over 14 days, with an average particle size consistently maintained at approximately 45 nm and no significant aggregation observed, confirming the long-term stability of the formulation under low temperature conditions. Based on the results of the hot and cold storage tests, it can be concluded that the pesticide suspension concentrate prepared in Example 4 exhibits good storage stability over a wide temperature range, meeting the requirements of practical applications.

[0131] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0132] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A pesticide aqueous suspension concentrate, characterized in that: The pesticide aqueous suspension contains nanoparticles obtained by supramolecular self-assembly of tea saponin and hydrophobic pesticide, wherein the nanoparticles have an average particle size of 40nm-150nm, a polydispersity index of 0.05-0.37, and an absolute value of a surface potential greater than 30mV.

2. The pesticide aqueous suspension concentrate according to claim 1, wherein The mass fraction of the nanoparticles in the pesticide aqueous suspension concentrate is 4.05%-17.43%.

3. The pesticide aqueous suspension concentrate according to claim 1, wherein The mass ratio of the tea saponin to the hydrophobic pesticide is 1.06:1-3.24:

1.

4. The pesticide aqueous suspension concentrate according to any one of claims 1 to 3, characterized in that The hydrophobic pesticide is selected from at least one of chlorpyrifos, cypermethrin, prochloraz, triadimefon, difenoconazole and flusilazole.

5. A method for preparing the pesticide aqueous suspension concentrate according to any one of claims 1 to 4, characterized in that: The steps include: mixing a hydrophobic pesticide and a tea saponin extract to obtain a mixed solution, wherein the mass ratio of the hydrophobic pesticide to the tea saponin extract is 1:99-1:9; Under stirring, the mixed liquid is heated and then cooled to form nanoparticles to obtain a pesticide aqueous suspension concentrate, wherein the stirring speed is 200 rpm-800 rpm, the heating treatment temperature is T1, the melting point temperature of the hydrophobic pesticide is T2, T2<T1<T2+20°C, and the cooling temperature is T3, T3<T2.

6. The method for preparing the pesticide aqueous suspension concentrate according to claim 5, wherein: The melting point temperature T2 of the hydrophobic pesticide is lower than 100°C.

7. The method for preparing the pesticide aqueous suspension concentrate according to claim 5, wherein: The mass fraction of tea saponin in the tea saponin extract is 10%-20%.

8. The method for preparing the pesticide aqueous suspension concentrate according to claim 5, wherein The heating time is 2h-10h; And / or, the cooling temperature T3 is room temperature, and the cooling time is 2h-5h.

9. The method for preparing the pesticide aqueous suspension concentrate according to any one of claims 5 to 8, wherein: The preparation method of the pesticide aqueous suspension further comprises the following steps: after cooling to form nanoparticles, an auxiliary agent is added and mixed to obtain the pesticide aqueous suspension, wherein the auxiliary agent is selected from at least one of an antifreeze agent and a thickener.

10. Use of the pesticide aqueous suspension concentrate according to any one of claims 1 to 4 in preventing and controlling plant diseases and insect pests.

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