A flutianil nano-pesticide containing copper ions and tannic acid and a preparation method thereof

Abstract

The application provides a kind of copper ion and tannic acid-containing flutianil nano pesticide and a preparation method thereof.The preparation method comprises the following steps: tannic acid and flutianil are dissolved in organic solvents respectively, two kinds of mother liquor are mixed in proportion, then dropped into deionized water, stirred overnight, and centrifuged to remove free drugs, to obtain a TO nano core solution; then the TO solution is dropped into a copper sulfate solution, stirred and centrifuged, to obtain a copper ion and tannic acid-containing flutianil TOC nano pesticide. The nano structure successfully combines tannic acid and flutianil, and is modified by copper ions, to realize the reduction of particle size, the improvement of stability, the improvement of pesticide utilization rate, and the significant improvement of the prevention and treatment effect of soybean root rot, cowpea wilt, litchi blight and other crop diseases caused by soybean phytophthora, cowpea phytophthora, litchi blight, palm phytophthora, camphor phytophthora and taro phytophthora. The application has significant environmental and economic value.

Description

Technical Field

[0001] This invention relates to the field of agricultural biotechnology, and in particular to a fluthiazopyrone nanopesticide containing copper ions and tannic acid, and its preparation method. Background Technology

[0002] Copper ions are essential micronutrients for plant growth, participating in key physiological processes such as electron transport (e.g., photosynthesis and respiration), enzyme activity, cell wall formation, oxidative stress resistance, and protein metabolism. Copper-based fungicides have been used in agricultural production for over 140 years. Besides their well-known ability to kill pathogens through heavy metal toxicity and isolation, copper preparations have recently been shown to act as elicitors to induce plant resistance. This explains why, even after the long-term use of copper-based fungicides has led to the emergence of copper-resistant strains, spraying copper-based fungicides can still effectively control diseases.

[0003] Fluthiazopyrone, developed by DuPont in 2007, is a novel oomycete fungicide with a novel mechanism of action. Studies have shown that it effectively inhibits pathogen signal transduction and lipid metabolism by specifically binding to oxidosterol-binding protein (OSBP), thereby achieving excellent control effects. Currently, this agent has been registered in my country for the control of various crop diseases such as potato late blight and grape downy mildew, and studies have also confirmed its good efficacy against tobacco black shank. As the most active oomycete inhibitor currently available, fluthiazopyrone has become an important choice in resistance management strategies under the policy of promoting pesticide reduction and efficiency enhancement, and its application scope is expected to continue to expand. However, the increase in application also brings potential environmental risks. Fluthiazopyrone has extremely low solubility in water (<0.01 mg / L), and after field application, it is easily washed away by rainwater and degraded by ultraviolet light, resulting in a shortened effective period and reduced effective utilization rate. Frequent application is required to maintain efficacy, increasing the cost of pesticide use and environmental risks.

[0004] Nanopesticide technology, by reducing the particle size of pesticide active ingredients to the nanoscale, can significantly increase specific surface area, improve dispersibility, enhance leaf adhesion, and target delivery capabilities, and has been regarded as an effective strategy to overcome the bottlenecks of traditional formulations. In recent years, pesticide delivery systems based on metal-phenolic networks (MPNs) have attracted widespread attention. This system utilizes the catechol / pyrogallol groups of natural polyphenols such as tannins to coordinate with metal ions and self-assemble into functional nanocoatings, possessing multiple functions such as pH-responsive release, ultraviolet light shielding, enhanced leaf adhesion, and synergistic antibacterial activity with metal ions.

[0005] However, the above-mentioned existing technologies still have the following shortcomings: tannic acid is only used as a shell coating material and does not participate in the construction of the active ingredient core, so its function is not fully utilized; most systems rely on inorganic or polymer carriers (such as mesoporous silica, MOF, attapulgite, etc.) to provide structural support, the preparation process is complicated, the carrier itself has no bactericidal activity, and exogenous inactive components are introduced. Therefore, developing a new formulation of fluthiazopyrone nanopesticide that uses tannic acid to participate in the construction of both the core and shell layers, requires no external inorganic carrier, and has a simple process, is of great significance for fully realizing its efficacy potential and minimizing its environmental footprint. Summary of the Invention

[0006] In view of this, the present invention proposes a fluthiazopyrone nanopesticide containing copper ions and tannic acid and its preparation method, thereby solving the above problems.

[0007] The technical solution of this invention is achieved as follows: a method for preparing a fluthiazopyrone nanopesticide containing copper ions and tannic acid, comprising the following steps: S1, fluthiazopyrone was dissolved in organic solvent a to prepare a solution with a concentration of 10.0 mg·mL. -1 Fluorothiazol pyridine mother liquor; S2. Tannic acid was dissolved in organic solvent b to obtain a solution with a concentration of 10.0 mg·mL. -1 Tannic acid mother liquor; S3. Dissolve copper sulfate in water to prepare a solution with a concentration of 1.0 mg / mL. -1 Copper sulfate mother liquor; S4. Mix the fluthiazopyrone mother liquor and tannic acid mother liquor obtained in steps S1 and S2 to obtain a solution. S5. The solution described in step S4 is added dropwise to deionized water, stirred and centrifuged to remove residual free drug. Fluthiazopyrone and tannic acid self-assemble through hydrophobic interaction and hydrogen bonding to form a homogeneous TO nanocore solution. S6. The nano-core solution from step S5 is added dropwise to the copper sulfate mother liquor from step S3. After stirring, the residue of free drug is removed by centrifugation to obtain the fluthiazopyrone TOC nano-pesticide containing copper ions and tannic acid.

[0008] Further, in step S1, the organic solvent a is methanol (MeOH); in step S2, the organic solvent b is dimethyl sulfoxide (DMSO).

[0009] Furthermore, the water mentioned in steps S3 and S5 is deionized water.

[0010] Further, in step S4, the fluthiazopyridine mother liquor and the tannic acid mother liquor are mixed at a molar ratio of fluthiazopyridine to tannic acid of 1:(1~10); the mixing condition is to mix at a temperature of 22°C for 10 min.

[0011] Furthermore, the stirring temperature in steps S5 and S6 is 22°C, the centrifugal force is 13528×g, and the centrifugation time is 5min.

[0012] Fluthiazopyrone nanopesticides containing copper ions and tannic acid were prepared by the above method.

[0013] The above-mentioned application of the fluthiazopyrone nanopesticide containing copper ions and tannic acid in the prevention and control of plant diseases caused by oomycete pathogens.

[0014] Preferably, the oomycete pathogen is Phytophthora soybeanii (…). Phytophthora sojae ), Phytophthora indicum ( Phytophthora litchii ), Phytophthora indicum ( Phytophthora vignae Phytophthora indicum (Phytophthora) colocasiae Phytophthora palmis ( ) Phytophthora palmivora ) and Phytophthora camphorata ( Phytophthora cinnamomi One or more of the following.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a unique stepwise self-assembly structure of "nucleation first, modification later". First, fluthiazopyrone and tannic acid form a uniform TO nanonucleus through hydrophobic interactions and non-covalent interactions such as hydrogen bonding. Subsequently, copper ions coordinate with the exposed tannic acid phenolic hydroxyl groups on the surface of the TO nanonucleus, constructing a dense copper-tannic acid metal-polyphenol network functional layer on the outer layer of the nanoparticles. This surface modification strategy effectively anchors copper ions to the surface of the nanoparticles, avoiding the defect of premature cross-linking of tannic acid and metal ions in the solution phase to form blocky precipitates. Furthermore, the high specific surface area at the nanoscale fully exposes the surface Cu-TA active sites, effectively improving the dispersibility, wettability, retention capacity, UV degradation resistance, and drug release behavior of fluthiazopyrone.

[0016] 2. This invention requires no other carrier and forms nano-pesticide TO entirely from tannic acid and fluoxetine, followed by surface modification with copper ions. It has a high self-assembly rate and good stability.

[0017] 3. This invention is convenient and simple to operate, and the resulting nano-pesticide can significantly improve the efficacy of fluthiazopyrone. This nano-pesticide shows great promise in controlling oomycete pathogens. Attached Figure Description

[0018] Figure 1The images show the comprehensive characterization of the TO nanonucleus solutions prepared in various examples of this invention. From left to right, the images show samples prepared under raw material molar ratios of 8:1, 2:1, 1:1, 1:2, 1:4, 1:8, and 1:10. From top to bottom, the first row shows the morphology of the samples obtained under transmission electron microscopy (TEM), the second row shows the appearance of the Tyndall effect, and the third row shows the particle size distribution of DLS.

[0019] Figure 2 The image shows the physicochemical properties of the TOC nanopesticide prepared in Example 1 of this invention. Figure 2 In the image, 'a' represents a transmission electron microscope image. Figure 2 In the diagram, b represents the particle size distribution of DLS. Figure 2 In the image, 'c' represents the particle size distribution image stored for 14 days. Figure 2 In this context, d represents the ultraviolet absorption spectrum. Figure 2 The elemental analysis diagram shows carbon, nitrogen, sulfur, fluorine, and copper from left to right.

[0020] Figure 3 The graph shows the inhibitory effects of the TOC nanopesticide prepared in Example 1 of this invention and different materials on Phytophthora soybeana, Phytophthora litchiensis, Phytophthora cowpeaa, Phytophthora palmatum, Phytophthora taroa, and Phytophthora camphora.

[0021] Figure 4 The graph shows the development of leaf lesions caused by different concentrations of OXA and TOC against three Phytophthora blight pathogens. Figure 4 In this context, 'a' represents Phytophthora licheniformis. Figure 4 In this context, 'b' represents Phytophthora cowpeaii. Figure 4 In this context, 'c' represents Phytophthora soybeanae.

[0022] Figure 5 This is a diagram showing the effect of the TOC nanopesticide prepared in Example 1 of this invention on seed germination. Figure 5 In this context, 'a' represents soybean seeds. Figure 5 In this context, 'b' represents cowpea seeds. Detailed Implementation

[0023] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0024] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0025] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0026] Example 1 A method for preparing a fluthiazopyrone nanopesticide containing copper ions and tannic acid includes the following steps: S1. Accurately weigh 10.0 mg of fluthiazopyrone and add it to 1.0 mL of methanol (MeOH). Sonicate the solution for 10 min to ensure complete dissolution, yielding 10.0 mg / mL. -1 Fluorothiazol pyridine mother liquor.

[0027] S2. Accurately weigh 10.0 mg of tannic acid and add it to 1.0 mL of dimethyl sulfoxide (DMSO). Sonicate the solution for 10 min to ensure complete dissolution, yielding 10.0 mg / mL. -1 Tannic acid mother liquor.

[0028] S3. Accurately weigh 1.0 mg of copper sulfate and add it to 1.0 mL of deionized water. Sonicate the solution for 10 min to fully dissolve it, yielding 1.0 mg / mL. -1 Copper sulfate mother liquor.

[0029] S4. Mix the fluthiazopyridine solution and tannic acid solution at the optimal molar ratio of 1:4 and sonicate them in a water bath at room temperature (22°C) for 10 minutes to obtain a mixed solution.

[0030] S5. Add the mixed solution dropwise to 2.0 mL of deionized water and stir overnight (8 h) at room temperature (22 °C). Then centrifuge at 13528 × g for 5 min, remove the supernatant, and resuspend in 2.0 mL of deionized water. Repeat three times to remove free residual drug and obtain TO nanonucleus solution.

[0031] S6. Add the TO nanonucleus solution dropwise to a concentration of 1.0 mg·mL⁻¹. -1 The sample was stirred in a copper sulfate mother liquor at room temperature for 8 hours. Then, it was centrifuged at 13528×g for 5 minutes. After removing the supernatant, the sample was resuspended in 2.0 mL of deionized water. This process was repeated three times to remove any remaining free pesticide, yielding a fluthiazopyrone TOC nanopesticide containing copper ions and tannic acid.

[0032] The contents of fluthiazopyrone and tannic acid in the above-mentioned fluthiazopyrone nanopesticide were determined by high performance liquid chromatography.

[0033] Example 2 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and the tannic acid solution were mixed at a molar ratio of 1:1.

[0034] Example 3 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and the tannic acid solution were mixed at a molar ratio of fluthiazolpidem ketone to tannic acid of 1:2.

[0035] Example 4 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and tannic acid solution were mixed at a molar ratio of fluthiazolpidem ketone to tannic acid of 1:8.

[0036] Example 5 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and tannic acid solution were mixed at a molar ratio of fluthiazolpidem ketone to tannic acid of 1:10.

[0037] Comparative Example 1 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and tannic acid solution were mixed at a molar ratio of 8:1.

[0038] Comparative Example 2 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and the tannic acid solution were mixed at a molar ratio of 4:1.

[0039] Comparative Example 3 The same preparation method as in Example 1 was used, except that in step S4, the fluthiazolpidem ketone solution and the tannic acid solution were mixed at a molar ratio of fluthiazolpidem ketone to tannic acid of 2:1.

[0040] Test Example 1: Characterization and determination of TO nanonucleus solutions synthesized at different molar ratios To observe the physical morphology of TO nanonucleus solutions synthesized at different molar ratios, TEM images were obtained using transmission electron microscopy. Dynamic light scattering (DLS) was used to characterize the size and PDI of the TO nanonucleus solutions synthesized at different molar ratios, as well as the Tyndall effect. Figure 1 ).

[0041] Transmission electron microscopy (TEM) results showed that the molar ratio of the reactants significantly controlled the microstructure of the nanoparticles. At molar ratios of 8:1 and 4:1, the synthesized products did not form regular spherical structures, but rather exhibited irregular network or loose flocculent morphology. When the molar ratio decreased to 2:1, the products aggregated into larger, irregular clumps. Further increasing the proportion of the subsequent component (molar ratio from 1:1 to 1:10) resulted in a significant change in product morphology, with all products forming regular spherical nanoparticles. Under molar ratios of 1:4, 1:8, and 1:10, the particles exhibited excellent dispersibility, and the TEM images clearly showed that the diameter of the spherical particles gradually increased with increasing proportions of the subsequent component (from 1:4 to 1:10).

[0042] Optical photographs show that all dispersions prepared at different molar ratios exhibit a significant Tyndall effect, indicating that each sample formed a stable colloidal dispersion without macroscopic precipitation. Simultaneously, as the molar ratio gradually approaches 1:10, the system's appearance color changes from nearly transparent to pale pink / milky white, consistent with the enhanced Rayleigh scattering effect caused by the increased size of nanoparticles in the solution.

[0043] Dynamic light scattering (DLS) particle size distribution results showed that the particle size distribution curves of each group of samples were all single-peaked and narrow-peaked, proving that the nanoparticles synthesized within the studied molar ratio range all had good monodispersity. The hydrated particle size test results were in high agreement with the TEM observation results. As the molar ratio transitioned from 1:1 to 1:10, the main peak of the particle size distribution curve shifted to the right continuously, indicating that the average hydrodynamic size of the nanoparticles gradually increased.

[0044] Finally, combining electron microscopy observations, dynamic light scattering (DLS) particle size measurements, and Tyndall effect results, a molar ratio of 1:4 was determined as the optimal ratio for the formation of TO nanonuclei from fluoxetine solution and tannic acid solution, and this ratio was subsequently improved.

[0045] Test Example 2: Characterization and Determination of TOC Nanopesticides To observe the physical morphology of TOC, TEM images were obtained using transmission electron microscopy (TEM), and the size and PDI of the prepared TOC were characterized using dynamic light scattering (DLS). The particle size change of TOC over 14 days at room temperature was measured to evaluate its colloidal stability. Its UV absorption spectrum (200–400 nm) was detected using a UV spectrophotometer. Simultaneously, its elemental composition was analyzed using an energy-dispersive X-ray spectroscopy (EDX) instrument integrated with the TEM system.

[0046] Observed using a transmission electron microscope Figure 2 The image clearly shows that TOC nanopesticides are spherical nanoassemblies of about 260 nm. Figure 2 The dynamic light scattering results in b further demonstrate its excellent hydrodynamic particle size distribution and low polydispersity index, and its excellent colloidal stability is shown by monitoring its particle size change over 14 days at room temperature. Figure 2 (c in the text) Figure 2 The ultraviolet absorption spectrum of the d-phase further verified the successful preparation of TOC nanopesticides. Furthermore, elemental analysis was performed using an energy-dispersive X-ray spectroscopy (EDS) instrument on a TEM system, directly confirming the composition and distribution of the key copper element in the nanoparticles. Figure 2 (e in the text).

[0047] Test Example 3: Indoor Plate Antibacterial Determination To evaluate the inhibitory effect of TOC nanopesticides on the mycelial growth of oomycete pathogens, this study used the mycelial growth rate method for determination. *Phytophthora soybeani*, *Phytophthora lychee*, *Phytophthora cowpeai*, *Phytophthora palmi*, *Phytophthora taroi*, and *Phytophthora camphorata* were selected as test strains. Test agents included the TOC nanopesticide prepared in Example 1, fluoxetine technical, tannic acid, and copper sulfate solution. The stock solutions of each test agent were added to sterile thawed V8 medium, thoroughly mixed, and brought to a final volume of 50.0 mL to obtain a final test concentration of 0.001 mg / mL. -1 Prepare drug-containing agar plates and allow them to solidify for later use. Using a sterile knife, cut 3mm × 3mm hyphal fragments from the edge of each pathogen colony after 5 days of culture and inoculate them into the center of the drug-containing agar plate. Incubate the plates in a 25℃ incubator. When the hyphae grow to the edge of the culture medium, measure the colony diameter of each treatment using the cross-crossing method and calculate the inhibition rate to compare the antibacterial activity of different agents.

[0048] The mycelial growth inhibition rate is calculated using the following formula:

[0049] Table 1: Antimicrobial effects of different materials on Phytophthora soybeani, Phytophthora litchiensis, Phytophthora cowpeai, Phytophthora palmi, Phytophthora taroi, and Phytophthora camphori.

[0050] Figure 3 Images show the inhibitory effects of the TOC nanopesticide, fluoxetine technical grade, tannic acid, and copper ions prepared in Example 1 on *Phytophthora sojae*, *Phytophthora licheniformis*, *Phytophthora cowpeai*, *Phytophthora palmiformis*, *Phytophthora taroi*, and *Phytophthora camphorata*. Figure 3 As shown, compared with the blank control, at the same concentration of 0.001 mg·mL -1 The TOC nanopesticide and fluthiazopyrone technical prepared in the following embodiments of the invention both showed excellent inhibitory effects on these pathogenic oomycetes, and the inhibitory effect of the TOC nanopesticide of the present invention was significantly better than that of fluthiazopyrone technical. Tannic acid and copper ions, however, did not show any inhibitory effect on these pathogenic oomycetes.

[0051] Experimental results show that the antibacterial effect of the TOC nanopesticide of this invention is significantly better than that of fluthiazopyrone technical, and the improvement is unrelated to the antibacterial ability of the natural compound itself. This is because copper ions are effectively anchored to the surface of the nanoparticles, and the high specific surface area at the nanoscale fully exposes the Cu-TA active sites, endowing TOC with significant nanozyme-mimicking activity. This allows it to actively regulate reactive oxygen species levels in the acidic microenvironment of pathogen infection, generating highly toxic free radicals to enhance oxidative stress on the pathogen. The results indicate that nano-sizing significantly improves the control effect of fluthiazopyrone against oomycete pathogens.

[0052] Test Example 4: Determination of the protective effect of TOC nanopesticides on litchi leaves, cowpea leaves, and soybean leaves. To investigate the protective effect of TOC nanopesticide on soybean leaves, lychee leaves, and cowpea leaves, detached leaves were used in the following experiment: leaves from soybean and cowpea seedlings that were 7 days old, uniform in size, and free of disease spots, and leaves from lychee seedlings that were 14 days old were selected. All leaves were rinsed three times with sterile deionized water before use. The TOC nanopesticide prepared in Example 1 and the fluthiazopyr acetone technical were prepared at concentrations of 0.1, 0.2, and 0.5 mg / mL, respectively. -1 Three concentrations were applied. Leaves were placed face down in 150mm petri dishes lined with moistened filter paper, with the petioles wrapped in moistened filter paper to maintain moisture. Each concentration of solution was sprayed evenly, and the dishes were then incubated in a 25℃ dark incubator for 24 hours. After the pre-incubation, mycelial blocks of the corresponding pathogen were inoculated onto the leaf surface. After inoculation, the leaves were continued to be incubated at 25℃, kept in darkness for the first 24 hours, followed by alternating light and dark incubation. Disease incidence was observed regularly and photographed. To clearly visualize the lesions, soybean and cowpea leaves were photographed using a UV gel electrophoresis apparatus. Finally, the area of ​​lesions on all leaves was measured, and the inhibition rate of each treatment against the corresponding Phytophthora blight was calculated.

[0053]

[0054] Table 2: Protective effects of TOC nanopesticides on litchi leaves, cowpea leaves, and soybean leaves

[0055] Figure 4 Table 2 shows the protective effects of the TOC nanopesticide and fluthiazopyrone technical prepared in Example 1 on leaves. The results indicate that nano-modification significantly improved the broad-spectrum activity, rapid action, and low-dose activity of the pesticide. (0.1 mg·mL⁻¹) -1 At low concentrations, TOC nanopesticides showed inhibition rates of 93.68% and 100% against leaf diseases in litchi and cowpea, respectively, while the same concentration of fluoxetine technical grade pesticides only showed inhibition rates of 33.90% and 5.85%, respectively, representing an increase in activity of over 2.7 times and 16 times. This demonstrates that nano-modification significantly enhances the bioavailability of the active ingredient at low doses. As the concentration increased to 0.2 mg / mL... -1 The broad-spectrum synergistic advantages of TOC nano-pesticides are fully demonstrated: its inhibition rate against soybean leaf diseases is significantly better than that of the original pesticide; simultaneously, its inhibition rate against lychee and cowpea leaf diseases remains consistently above 95%, exhibiting balanced and efficient control over multiple diseases, while the original pesticide shows inconsistent efficacy and insufficient broad-spectrum activity under the same conditions. At a concentration of 0.5 mg / mL... -1At the time of testing, TOC nanopesticides achieved 100% complete inhibition of leaf diseases in all three crops. In contrast, fluthiazopyr technical grade only achieved complete inhibition of leaf diseases in litchi, while the inhibition rates for leaf diseases in soybeans and cowpeas were 38.27% and 80.45%, respectively, failing to achieve complete control. The above comparative experiments clearly demonstrate that TOC nanopesticides, prepared by nano-modifying fluthiazopyr technical grade, effectively improve the utilization rate of fluthiazopyr. This nano-formulation exhibits outstanding performance in significantly reducing the effective dosage and improving efficacy, solving the problem of insufficient activity of the technical grade at low concentrations, and providing an innovative technical solution for the efficient and reduced-dosage application of fluthiazopyr.

[0056] Test Example 5: Effects of TOC nanopesticides on the germination of soybean and cowpea seeds The safety of the TOC nanopesticide prepared in Example 1 was evaluated as follows: Ten soybean and cowpea seeds of similar size were selected, rinsed with water to remove surface impurities, and placed in a 60 mm petri dish. 15.0 mL of sterile deionized water was added and the seeds were soaked for 5 minutes. The seeds were then removed and air-dried. The concentration of the nanopesticide prepared in Example 1 was set to 5.0 mg / mL. -1 Prepare a 10.0 mL nano-pesticide solution and place soybean seeds in it, with sterile deionized water serving as a control. Change the seed soaking solution every 24 hours, and photograph and record the germination status after 48 hours. Figure 5 This illustrates the effect of the fluthiazopyrone nanopesticide prepared in Example 1 on the germination of soybean and cowpea seeds. Figure 5 It can be seen that the concentration of the fluthiazopyrone nanopesticide prepared in Example 1 is 5.0 mg·mL. -1 hour Figure 5 a soybean seeds and Figure 5 All cowpea seeds in group b germinated normally, and there was no significant difference compared with the blank control. This indicates that the fluoxetine nanopesticide of the present invention has no effect on the germination of soybean and cowpea seeds.

[0057] Overall, the fluthiazopyrone nanopesticide of the present invention has a significantly better control effect on pathogenic oomycetes than fluthiazopyrone technical, and its control effect is comparable to, or even better than, the commercially available pesticide Zengweiyinglv. The fluthiazopyrone nanopesticide of the present invention significantly improves the control effect, reduces the amount and frequency of pesticide use, and saves manpower and financial costs.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a fluthiazopyrone nanopesticide containing copper ions and tannic acid, characterized in that, Includes the following steps: S1, fluthiazopyrone was dissolved in organic solvent a to prepare a solution with a concentration of 10.0 mg·mL. -1 Fluthiazopyridine mother liquor; S2. Tannic acid was dissolved in organic solvent b to obtain a solution with a concentration of 10.0 mg·mL. -1 Tannic acid mother liquor; S3. Dissolve copper sulfate in water to obtain a solution with a concentration of 1.0 mg / mL. -1 Copper sulfate mother liquor; S4. Mix the fluthiazopyridine mother liquor and tannic acid mother liquor obtained in steps S1 and S2 at a molar ratio of fluthiazopyridine to tannic acid of 1:(1~10) to obtain a solution. S5. The solution described in step S4 is added dropwise to water, stirred and then centrifuged to remove residual free drug. Fluthiazopyrone and tannic acid self-assemble through hydrophobic interaction and hydrogen bonding to form a uniform nano-core solution. S6. The nano-core solution from step S5 is added dropwise to the copper sulfate mother liquor from step S3. After stirring, the residue of free drug is removed by centrifugation to obtain the fluthiazopyrone nano-pesticide containing copper ions and tannic acid.

2. The preparation method according to claim 1, characterized in that, In step S1, the organic solvent a is methanol; in step S2, the organic solvent b is dimethyl sulfoxide.

3. The preparation method according to claim 1, characterized in that, The water mentioned in steps S3 and S5 is deionized water.

4. The preparation method according to claim 1, characterized in that, The mixing conditions described in step S4 are mixing at a temperature of 22°C for 10 minutes.

5. The preparation method according to claim 1, characterized in that, The stirring temperature in steps S5 and S6 is 22°C; the centrifugal force in the centrifugation is 13528×g, and the centrifugation time is 5min.

6. A fluthiazopyrone nanopesticide containing copper ions and tannic acid, characterized in that, It is prepared by any one of claims 1 to 5.

7. The application of the fluthiazopyrone nanopesticide as described in claim 6 in the prevention and control of plant diseases caused by oomycete pathogens, wherein the oomycete pathogens include one or more of Phytophthora soybeani, Phytophthora litchiensis, Phytophthora cowpeai, Phytophthora taroi, Phytophthora palmi, and Phytophthora camphori.

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