Osthole@nanozyme nano-pesticide, preparation method thereof and application thereof

Abstract

The present invention belongs to the technical field of pesticides, and particularly relates to osthole@nanozyme nano-pesticides and their preparation methods and applications. In the present invention, a bionic nanozyme is used to load the plant-derived fungicide osthole. Under acidic conditions at the disease site, the nanozyme can catalyze H2O2 to generate ·OH, playing a role in synergistic antifungal effect, reducing the amount of drugs used while increasing efficiency, and at the same time avoiding the problem of drug resistance caused by excessive use of antibacterial drugs. At the same time, the nanozyme separates osthole from the external environment, solves the problem of easy photolysis of plant-derived pesticides, reduces the number of drug applications, and improves the drug stability. The osthole@nanozyme nano-pesticides of the present invention have good stability, and at the same time the loaded pesticide components are natural and green, and are harmless to humans, the environment and livestock.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides, and particularly relates to a osthole@nanozyme nano-pesticide, a preparation method thereof, and an application thereof. Background Art

[0002] Rhizoctonia solani belongs to the pathogen of damping-off disease and is a highly destructive filamentous fungus. It can infect a variety of plants, including rice, potatoes, peanuts, ginseng, etc. In order to achieve high-quality and high-yield crops, a large number of synthetic pesticides are currently widely used to inhibit the occurrence of diseases. However, traditional pesticides containing different additives usually have disadvantages such as poor solubility of the formulation, unstable performance, and easy photolysis. The unreasonable use of pesticides has led to excessive pesticide residues, seriously affecting the quality and safety of traditional Chinese medicines. In addition, the preparation of traditional pesticides involves the use of a large amount of organic solvents, which seriously affects the stability of the ecosystem at the sub-level and soil fertility, is toxic to non-target organisms, and most bacteria or fungi will develop drug resistance over time. Therefore, the development of efficient and safe green pesticides is of great significance for crop disease control and agricultural sustainable development.

[0003] The active ingredient of plant-derived fungicides is a natural substance, which is relatively easy to decompose into non-toxic substances after application, is environmentally friendly, and due to the diversification of its components, it is difficult for pathogens to develop drug resistance. As a plant-derived fungicide, osthole has a variety of biological activities and has been used for a long time to control plant pathogens and pests. However, osthole has problems such as slow drug efficacy and poor persistence due to easy photolysis, making its bactericidal effect far from comparable to that of traditional chemical pesticides. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a osthole@nanozyme nano-pesticide, a preparation method thereof, and an application thereof. By the synergistic bactericidal effect of nanozyme and osthole, the bactericidal effect is effectively improved, the problem of easy photolysis of osthole is avoided, and the stability and persistence are improved.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows.

[0006] The first aspect of the present invention provides a preparation method of a osthole@nanozyme nano-pesticide, comprising the following steps:

[0007] Mix nanozyme and osthole in an organic reagent environment and react for 6 h to 24 h to load osthole on the nanozyme, wash, centrifuge to obtain the precipitate, and dry to obtain the osthole@nanozyme nano-pesticide;

[0008] The mass ratio of the nanozyme to osthole is 1:4 - 6; the nanozyme is obtained by mixing zinc nitrate solution and 2-methylimidazole solution in equal volume and reacting for 4 h - 6 h, centrifuging to obtain the precipitate, drying, and calcining; the zinc nitrate solution is obtained by mixing zinc nitrate hexahydrate and methanol solution according to the molar volume ratio of 9 mmol - 11 mmol:100 mL; the 2-methylimidazole solution is obtained by mixing 2-methylimidazole and methanol solution according to the molar volume ratio of 32 mmol - 34 mmol:100 mL.

[0009] In the preparation process of the nanozyme, excessive 2-methylimidazole is deprotonated to coordinate with zinc ions to form crystal nuclei, and then the crystal nuclei grow rapidly to form ZIF-8 nanocrystal particles. Finally, neutral 2-methylimidazole binds to positively charged ZIF-8 to terminate the reaction. The growth of ZIF-8 in solution is completed by the diffusion and subsequent binding of small monomers on the crystal surface. The growth on the crystal nucleus surface depends on the supersaturation level of the reagent. That is, at a lower supersaturation, the relative supersaturation on the crystal surface is higher, so the growth of ZIF-8 is two-dimensional growth; as the supersaturation increases, the driving force for crystal growth increases, and the growth units begin to integrate into any position on the crystal surface, finally obtaining a complete crystal. 2-methylimidazole and zinc nitrate hexahydrate are respectively dissolved in methanol to form homogeneous solutions and then mixed with each other, so as to promote the effective coordination of 2-methylimidazole and zinc ions, and then form ZIF-8 crystals. Methanol solvent is required during the synthesis process to avoid affecting the size and morphology of ZIF-8 crystals.

[0010] In the present invention, by controlling the mass ratio of the nanozyme to osthole, the content of osthole in the nanozyme as a carrier is ensured. The nanozyme is ZIF-8 formed with zinc ions in zinc nitrate hexahydrate as the coordination center and 2-methylimidazole as the ligand, belonging to a metal-organic framework, with a morphology of a rhombic dodecahedron. After high-temperature carbonization in a tubular furnace, a nanozyme carrier with biomimetic enzyme activity is obtained. This nanozyme carrier can catalyze H 2 O 2 into ·OH free radicals in the acidic microenvironment at the plant disease site, playing a role in synergistic sterilization. Encapsulating osthole in the nanozyme can effectively avoid photodegradation and at the same time avoid the problem of drug resistance caused by excessive use of antibacterial drugs.

[0011] In another preferred embodiment, the calcination temperature is 600 °C - 800 °C, and the calcination time is 2 h - 4 h.

[0012] In another preferred embodiment, the drying temperature is 60 °C - 80 °C, and the drying time is 12 h - 24 h.

[0013] In another preferred embodiment, the rotation speed of centrifugation is 12,000 rpm to 14,000 rpm, the number of centrifugation times is 1 to 3 times, and the centrifugation time is 10 min to 20 min.

[0014] In another preferred embodiment, the organic reagent is ethanol; the mass-volume ratio of osthole to ethanol is 9 mg to 11 mg: 1 mL.

[0015] The second aspect of the present invention provides the osthole@nanozyme nano-pesticide.

[0016] The third aspect of the present invention provides the application of the osthole@nanozyme nano-pesticide in preventing and controlling agricultural diseases.

[0017] In another preferred embodiment, the agricultural disease is an agricultural disease caused by Rhizoctonia solani.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The osthole@nanozyme nano-pesticide prepared in the present invention uses nanozyme to load the plant-derived pesticide osthole. Under acidic conditions at the disease site, the nanozyme catalyzes H 2 O 2 to generate ·OH, which acts synergistically with osthole to play an antifungal role. Under the action of the nanozyme, the problem of slow efficacy of osthole can be effectively solved. At the same time, under the condition of reducing the amount of pesticide used, the antifungal effect can be further improved, thus avoiding the problem of drug resistance caused by excessive use of antibacterial drugs.

[0020] The nanozyme in the present invention can separate osthole from the external environment, solve the problem of easy photolysis of osthole, reduce the number of drug administrations, and improve the drug stability.

[0021] (2) The nanozyme particles in the present invention are uniform and have good dispersion. The average particle size of the nanozyme is between 60 nm and 100 nm, and the size is uniform. Description of the Drawings

[0022] Figure 1 It is a scanning electron microscope image of the osthole@nanozyme nano-pesticide prepared in Example 1.

[0023] Figure 2 It is a particle size statistical data graph of OS@ZnSA. In the figure, OS in OS@ZnSA represents osthole, ZnSA represents nanozyme, and OS@ZnSA represents nanozyme loaded with osthole, that is, osthole@nanozyme nano-pesticide.

[0024] Figure 3 It is an infrared spectrum diagram of OS@ZnSA in Example 1.

[0025] Figure 4 It is the standard curve graph of osthole.

[0026] Figure 5 It is the graph of POD-like enzyme activity of the osthole@nanozyme nanopesticide prepared in Example 1.

[0027] Figure 6 It is the in vitro drug release graph of the osthole@nanozyme nanopesticide prepared in Example 1.

[0028] Figure 7 It is the stability analysis graph of the osthole@nanozyme nanopesticide prepared in Example 1. Among them, A is the stability result graph of OS under ultraviolet lamp irradiation, B is the stability result graph of OS@ZnSA at 0 °C, and C is the stability result graph of OS@ZnSA at 54 °C.

[0029] Figure 8 It is the in vitro antifungal activity graph of different pesticides. Among them, a is the in vitro antifungal activity graph of the blank control group, b is the in vitro antifungal activity graph of H 2 O 2 's in vitro antifungal activity graph, c is the in vitro antifungal activity graph of acetone, d is the in vitro antifungal activity graph of ZnSA, e is the in vitro antifungal activity graph of OS, f is the in vitro antifungal activity graph of the combination of ZnSA and H 2 O 2 's in vitro antifungal activity graph, g is the in vitro antifungal activity graph of OS@ZnSA, and h is the in vitro antifungal activity graph of the combination of OS@ZnSA and H 2 O 2 's in vitro antifungal activity graph.

[0030] Figure 9 The biosafety graph of the nanozyme in Example 1. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods; unless otherwise specified, the reagents and materials can all be purchased in the market.

[0033] The present invention utilizes that the Rhizoctonia solani infects plant parts to produce H 2 O 2Based on the characteristics of [substance name] and the decrease in pH, a osthole@nanozyme nano-pesticide is provided. By loading the plant-derived fungicide osthole with a biomimetic nanozyme, osthole is separated from the external environment, solving the problem of easy photolysis of plant-derived pesticides, reducing the number of pesticide applications, improving the drug stability. At the same time, under acidic conditions at the disease site, the nanozyme can also catalyze H 2 O 2 to generate ·OH, playing a synergistic antifungal role. While reducing the amount of drugs and increasing efficiency, it also avoids the problem of drug resistance caused by excessive use of antibacterial drugs. This osthole@nanozyme nano-pesticide has good stability, and the loaded pesticide components are natural and green, harmless to humans, the environment and livestock.

[0034] In the embodiments of the present invention, the room temperature is uniformly calculated as 25±2°C.

[0035] The epidermal cells in the following examples were purchased from Fuheng Biotechnology Co., Ltd.; fetal bovine serum was purchased from CLARKFB15015 high-quality fetal bovine serum; penicillin / streptomycin was purchased from Sevier Biotechnology Co., Ltd.; DMEM medium was purchased from gibco DMEM high-glucose liquid medium; osthole was purchased from Shanghai Macklin Biochemical Co., Ltd.

[0036] Example 1: A preparation method of an osthole@nanozyme nano-pesticide.

[0037] S1. Dissolve 10 mmol of zinc nitrate hexahydrate in 100 mL of methanol by ultrasonic to obtain a zinc nitrate hexahydrate solution, and dissolve 34 mmol of 2-methylimidazole in 100 mL of methanol by ultrasonic to obtain a 2-methylimidazole solution; mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volume and stir. After continuously stirring at 25°C for 5 h, centrifuge at 12000 rpm for 15 min. Ultrasonically disperse and centrifuge the obtained solid with methanol three times, and then dry the obtained solid in a vacuum drying oven at 80°C for 16 h to obtain the dried solid.

[0038] S2. Grind the dried solid into powder and put it into a tube furnace, and calcine it at 800°C for 3 h to obtain the nanozyme.

[0039] S3. Mix the nanozyme and osthole in a mass ratio of 1:5, dissolve them in ethanol to obtain a mixed solution; the mass-volume ratio of osthole to ethanol is 10 mg:1 mL; after ultrasonically dispersing the mixed solution evenly, stir it at 25°C for 12 h, then evaporate the liquid, wash the sample three times with ethanol, centrifuge and discard the supernatant, and freeze-dry the remaining solid to obtain the osthole@nanozyme nano-pesticide.

[0040] Example 2: A preparation method of an osthole@nanozyme nano-pesticide.

[0041] S1. Ultrasonically dissolve 9 mmol of zinc nitrate hexahydrate in 100 mL of methanol to obtain a zinc nitrate hexahydrate solution, and ultrasonically dissolve 32 mmol of 2-methylimidazole in 100 mL of methanol to obtain a 2-methylimidazole solution; mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volumes and stir, and continuously stir at room temperature of 25 °C for 4 h, then centrifuge for 10 min under the condition of 13,000 rpm. Ultrasonically disperse and centrifuge the centrifuged solid twice with methanol, and then dry the obtained solid in a vacuum drying oven at 60 °C for 12 h to obtain the dried solid.

[0042] S2. Grind the dried solid into powder and put it into a tubular furnace, and calcine at a high temperature of 600 °C for 4 h to obtain the nanozyme.

[0043] S3. Dissolve the nanozyme and osthole in a mass ratio of 1:4 in ethanol to obtain a mixed solution, where the mass-volume ratio of osthole to ethanol is 9 mg:1 mL; ultrasonically disperse the mixed solution evenly and stir at room temperature for 6 h, then evaporate the liquid, wash the sample three times with ethanol, centrifuge to discard the supernatant, and freeze-dry to obtain the osthole@nanozyme nanopesticide.

[0044] Example 3: A preparation method of an osthole@nanozyme nanopesticide.

[0045] S1. Ultrasonically dissolve 11 mmol of zinc nitrate hexahydrate in 100 mL of methanol to obtain a zinc nitrate hexahydrate solution, and ultrasonically dissolve 33 mmol of 2-methylimidazole in 100 mL of methanol to obtain a 2-methylimidazole solution; mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volumes, and continuously stir at room temperature of 25 °C for 6 h, then centrifuge for 20 min under the condition of 14,000 rpm. Ultrasonically disperse the centrifuged solid once with methanol, and then dry the obtained solid in a vacuum drying oven at 70 °C for 24 h to obtain the dried solid.

[0046] S2. Grind the dried solid into powder and put it into a tubular furnace, and calcine at a high temperature of 700 °C for 2 h to obtain the nanozyme.

[0047] S3. Dissolve the nanozyme and osthole in a mass ratio of 1:6 in an ethanol solution to obtain a mixed solution, where the mass-volume ratio of osthole to ethanol is 11 mg:1 mL. Ultrasonically disperse the obtained mixed solution evenly and stir at room temperature for 24 h, then evaporate the liquid, wash the sample three times with ethanol, centrifuge to discard the supernatant, and freeze-dry to obtain the osthole@nanozyme nanopesticide.

[0048] 1. Structural characterization.

[0049] Figure 1It is the scanning electron microscope image of the osthole@nanozyme nano-pesticide prepared in Example 1. Hereinafter, the osthole@nanozyme nano-pesticide is denoted as OS@ZnSA, OS is denoted as osthole, and ZnSA represents nanozyme.

[0050] It can be seen from Figure 1 that OS@ZnSA presents a rhombic dodecahedron.

[0051] Figure 2 It is the particle size statistical data graph of OS@ZnSA in Example 1. The results show that the average particle size of OS@ZnSA is 81.2 nm ± 5.8 nm.

[0052] Figure 3 It is the infrared spectrum of OS@ZnSA in Example 1. Fourier transform infrared spectroscopy was used to qualitatively analyze the sample. The characteristic peak appearing at 2220 cm −1 is attributed to the stretching vibration of the C≡N bond in ZnSA. The stretching vibration of C=O at 1712 cm −1 and the stretching vibration of aromatic C=C at 1600 cm −1 of OS were observed in OS@ZnSA, which further confirmed that OS was encapsulated in ZnSA.

[0053] 2. Effects of OS@ZnSA.

[0054] Weigh 16 mg of OS and make it up to the mother liquor in a 20 mL volumetric flask. Dilute the mother liquor into standard solutions of 40 μg / mL, 20 μg / mL, 10 μg / mL, 5 μg / mL, and 2.5 μg / mL respectively. Using a UV spectrophotometer, a standard curve was plotted with the standard solution concentration as the abscissa and the absorbance as the ordinate. As Figure 4 shown, its standard curve is y = 0.0585x + 0.0684, R 2 = 0.99991. The osthole loading rates in Examples 1 to 3 were determined according to the OS standard curve. The results are shown in Table 1.

[0055] Table 1 Osthole loading rates in Examples 1 to 3

[0056]

[0057] Figure 5 It is the graph of the POD-like enzyme activity of ZnSA prepared in Example 1. The POD-like enzyme activity of ZnSA was studied by the 3,3',5,5'-tetramethylbenzidine colorimetric method. The POD-like enzyme catalytic performance of ZnSA was measured in a 0.1 M acetic acid-sodium acetate buffer solution at pH 4.0. All reactions were carried out at 37 °C for 5 min. Among them, H 2 O 2The concentration was 25 mM, the TMB concentrations were 1 mM, 0.8 mM, 0.6 mM, 0.4 mM, 0.2 mM and 0 mM respectively, the ZnSA concentration was 50 μg / mL, the total reaction system was 400 μL. By measuring the absorbance at 652 nm, the enzymatic kinetics of ZnSA was studied, and the Lineweaver-Burk double reciprocal method was used to plot the graph. The results are as Figure 5 shown. The kinetic parameters K m and V max of TMB were 0.1262 mM and 4.228 μΜ / min respectively. The relatively high V max and relatively low K m highlighted its strong catalytic efficiency and applicability as an effective POD mimetic, indicating that ZnSA has excellent POD-like activity.

[0058] Figure 6 The in vitro drug release of OS@ZnSA in Example 1 was shown, and the release behavior of OS@ZnSA under different pH conditions was determined.

[0059] 5 mg of the OS@ZnSA sample was dispersed in 50 mL of a release medium with a methanol-to-water volume ratio of 6:4, and in vitro release was simulated in a shaker at 25 °C at a rotation speed of 120 rpm. At time intervals of 1 h, 2 h, 4 h, 8 h, 12 h, 24 h, 36 h, 48 h, 72 h, 96 h, 120 h, 144 h, 168 h, 192 h, 216 h, 240 h, 264 h, 288 h, 312 h, 336 h, 2 mL of the release medium was extracted and the same volume of fresh release medium was added to ensure a constant release system. The obtained release medium was centrifuged and filtered through a disposable filter, and then the concentration of OS was measured at a wavelength of 323 nm using a UV-visible spectrophotometer. The cumulative release amount of OS was calculated using the following formula:

[0060] .

[0061] Among them, OS cumulative release represents the cumulative release amount of OS, with the unit of %; V e is the volume of the release medium obtained at a given time interval, V e = 2 mL; V 0 is the volume of the release solution, V 0 = 50 mL; C n is the concentration of OS in the release medium at that time, with the unit of mg / L; m is the total mass of OS loaded in ZnSA, with the unit of mg.

[0062] The cumulative release behavior of OS@ZnSA at pH values of 5.0 and 7.0 was studied and monitored using a UV-Vis spectrophotometer. After 36 h of treatment, the cumulative release rate of OS@ZnSA at pH 5 was 17.4%, and at pH 7 was 16.9%. As time increased, the release tended to slow down, and the cumulative release rates at the 14th day were 51.0% and 45.6% respectively, indicating that acidic conditions were more favorable for drug release. After Rhizoctonia solani infects plants, it releases acidic toxic compounds such as phenylacetic acid, and the acidic environment at the disease site is more conducive to the release of the active ingredient in the nano-pesticide.

[0063] The stability of OS loaded in ZnSA nanoparticles and the OS original drug against UV exposure was compared. Suspensions of OS@ZnSA and OS containing the same concentration of OS were irradiated with a 36 W, 254 nm UV lamp at a distance of 10 cm from the light source. Monitoring was carried out at time intervals of 1 h, 2 h, 4 h, 9 h, 18 h, 28 h, 42 h, 56 h, 70 h, 84 h, and 96 h using a UV-Vis spectrophotometer, and the results are as Figure 7 shown in A of Figure 7 . It can be seen that after 96 h of UV irradiation, the residual rate of the OS original drug was only 45.1%, while the residual rate of OS in the ZnSA nano-carrier was as high as 96.3%. From this, it can be shown that ZnSA in the present invention has a good shielding effect on UV light as a carrier, and can effectively reduce the photodegradation of OS molecules in the pores. The shielding performance of ZnSA against UV light may be because it can absorb or reflect most of the UV light, thus greatly reducing the exposure of OS to UV light.

[0064] The storage stability of OS@ZnSA under different temperature conditions was evaluated, and the results are as Figure 7 shown in B and C of

[0065] Figure 8 . The OS@ZnSA solution was stored at 0 °C for 7 days and at 54 °C for 14 days, and then the content of OS was detected by a UV-Vis spectrophotometer, and the change in the hydrodynamic diameter was measured using a dynamic light scattering instrument. The results showed that the solution state was stable and uniform after low-temperature and high-temperature treatments, without obvious precipitation or stratification, and there were also no obvious changes in the hydrodynamic diameter of the hydrate and the content of OS during the storage of OS@ZnSA. For the in vitro antifungal activity of different pesticides, acetone and H 2 O 2 were used as solvent controls, ZnSA, OS, OS@ZnSA, the combination of ZnSA and H 2 O 2 , the combination of OS@ZnSA and H 2 O 2The combination was used as the experimental group, and the antibacterial activity of OS@ZnSA against Rhizoctonia solani was determined by the mycelial growth rate method. Among them, the effective concentration of OS was maintained at 250 μg / mL.

[0066] Under sterile conditions, Rhizoctonia solani discs with a diameter of 6 mm were inoculated into the center of potato dextrose agar Petri dishes containing the above-mentioned concentration of the reagent. After culturing for 4 days under dark conditions at 25 °C, the colony diameter was measured by the cross method, and the relative inhibition rate against Rhizoctonia solani was calculated. The test was performed in triplicate, and the results are as Figure 8 shown.

[0067] During the growth process, Rhizoctonia solani continuously secretes organic acids, and the acidic condition is conducive to the ZnSA to exert peroxidase-like enzyme activity. As Figure 8 shown in d of Figure 8 , ZnSA itself as a material has no inhibitory effect on the growth of Rhizoctonia solani, and the hyphal diameter has no significant difference from that of the control group. As Figure 8 shown in f of 2 O 2 , when ZnSA combines with H 2 O 2 , it will instantly catalyze H 2 O 2 to generate ·OH, resulting in the inactivation of the fungal cell wall and membrane structure due to damage, and its antibacterial effect reaches 53.81%. As Figure 8 shown in e and g of Figure 8 , when the concentration of OS is 250 μg / mL, the antibacterial rate of OS@ZnSA is 53.47%, and its antibacterial effect is slightly lower than the 65.26% antibacterial rate of the original OS drug. This may be due to the fact that ZnSA as a carrier enables the slow and long-term release of OS. As Figure 8 shown in e and h of 2 O 2 , OS@ZnSA and H 2 O 2 showed better inhibitory effects against Rhizoctonia solani on PDA plates, and its antibacterial rate was 90.6%. This indicates that ZnSA and OS in the nano-pesticide have a synergistic effect.

[0068] Figure 9 The biosafety of the OS@ZnSA prepared in Example 1 was shown. In the actual application process, the degradation of ZnSA will release various elements. Therefore, environmental safety is an important evaluation index. The biosafety of ZnSA was evaluated using human epidermal cells. Human epidermal cells HaCat in the logarithmic growth phase were inoculated onto 96-well plates and cultured at 37 °C for 24 h in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and 1% penicillin / streptomycin. The original culture medium was discarded and replaced with a drug-containing culture medium with a concentration of 250 μg / mL of nanoparticles for 24 h, and the cell viability was measured by the MTT method. It can be seen from Figure 9 that the nano-carrier has no obvious toxic effect on the growth of HaCat cells, indicating that the ZnSA nano-carrier has good biocompatibility and environmental safety.

[0069] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An osthole@nanozyme nanopesticide, characterized in that: The osthole@nanozyme nanopesticide is used to prevent and treat agricultural diseases caused by Rhizoctonia solani; The osthole@nanozyme nanopesticide is prepared by the following steps: The nanozyme and osthole are mixed and reacted in an organic reagent environment for 12 hours to 24 hours to load the osthole on the nanozyme, washed, centrifuged to obtain a precipitate, and dried to obtain osthole@nanozyme nanopesticide; the organic reagent is ethanol; the mass volume ratio of the osthole to the ethanol is 9 mg to 11 mg: 1 mL; The mass ratio of the nanozyme to the osthole is 1:4-6; The nanozyme is obtained by mixing equal volumes of zinc nitrate solution and 2-methylimidazole solution for reaction for 4 to 6 hours, centrifuging to obtain a precipitate, drying, and calcining; The zinc nitrate solution is obtained by mixing zinc nitrate hexahydrate and methanol in a molar volume ratio of 9 mmol to 11 mmol: 100 mL; The 2-methylimidazole solution is obtained by mixing 2-methylimidazole and methanol in a molar volume ratio of 32 mmol to 34 mmol: 100 mL.

2. The osthole@nanozyme nanopesticide according to claim 1, characterized in that: The calcination temperature is 600° C. to 800° C., and the calcination time is 2 h to 4 h.

3. The osthole@nanozyme nanopesticide according to claim 1, characterized in that: The drying temperature is 60° C. to 80° C., and the drying time is 12 h to 24 h.

4. The osthole@nanozyme nanopesticide according to claim 1, characterized in that: The centrifugal speed is 12000 rpm to 14000 rpm, and the centrifugal time is 10 min to 20 min.

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