Osthole-nano-enzyme nano pesticide as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pesticides, and particularly relates to an osthole and nano-enzyme nano-pesticide as well as a preparation method and application thereof. The biomimetic nano-enzyme is used for loading the botanical fungicide cnidium lactone, the nano-enzyme can catalyze H2O2 to generate. OH under the acidic condition of a disease part to play a synergistic antifungal role, the drug resistance problem caused by excessive use of an antibacterial drug is avoided while drug reduction and synergism are achieved, meanwhile, the nano-enzyme separates the cnidium lactone from the external environment, and the antibacterial effect is improved. The problem that a botanical pesticide is prone to photolysis is solved, the pesticide application frequency is reduced, and the pesticide stability is improved. The cnidium lactone and nano-enzyme nano-pesticide disclosed by the invention has good stability, and meanwhile, the loaded pesticide components are natural and green and are harmless to human, environment and livestock.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and specifically relates to an osthole@nanozyme nanopesticide and a preparation method and application thereof. Background Art

[0002] Rhizoctonia solani is a pathogen of damping-off disease and 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 dissolution, unstable performance, and easy photolysis. The irrational use of pesticides has led to excessive pesticide residues, which seriously affects the quality and safety of traditional Chinese medicine. In addition, the preparation of traditional pesticides involves the use of a large amount of organic solvents, which has a serious impact on the stability of the sub-level of the ecosystem and soil fertility, causes toxicity to non-target organisms, and most bacteria or fungi will develop resistance over time. Therefore, the development of efficient and safe green pesticides is of great significance for crop disease prevention and control and agricultural sustainable development.

[0003] The active ingredients of botanical fungicides are natural substances, which are easily decomposed into non-toxic substances after application. They are environmentally friendly and have a variety of ingredients, making it difficult for pathogens to develop drug resistance. As a botanical 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 the problem of slow efficacy and easy photolysis, resulting in poor durability, making its fungicide effect far less comparable to traditional chemical pesticides. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an osthole@nanozyme nanopesticide and a preparation method and application thereof. The synergistic bactericidal effect of nanozymes and osthole is effectively improved, and the problem of easy photolysis of osthole is avoided, thereby improving stability and durability.

[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 method for preparing osthole@nanozyme nanopesticide, comprising the following steps: The nanozyme and osthole are mixed and reacted in an organic reagent environment for 6 hours to 24 hours to load the osthole on the nanozyme, and then washed, centrifuged to obtain the precipitate, and dried to obtain the osthole@nanozyme nanopesticide; 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 4h~6h, centrifuging the precipitate, drying, and calcining; the zinc nitrate solution is obtained by mixing zinc nitrate hexahydrate and methanol solution in a molar volume ratio of 9mmol~11mmol:100mL; the 2-methylimidazole solution is obtained by mixing 2-methylimidazole and methanol solution in a molar volume ratio of 32mmol~34mmol:100mL.

[0007] In the process of nanozyme preparation, excess 2-methylimidazole is used to deprotonate and coordinate with zinc ions to form crystal nuclei, which then grow rapidly to form ZIF-8 nanocrystal particles. Finally, neutral 2-methylimidazole combines with positively charged ZIF-8 to terminate the reaction. The growth of ZIF-8 in solution is completed by the diffusion of small monomers on the crystal surface and subsequent combination. The growth of the crystal nucleus surface depends on the supersaturation level of the reagent, that is, at a lower supersaturation, the relative supersaturation of the crystal surface is higher, so the growth of ZIF-8 is two-dimensional growth; with the increase of supersaturation, the driving force of crystal growth increases, and the growth unit begins to integrate into any position on the crystal surface, and finally a complete crystal is obtained. 2-methylimidazole and zinc nitrate hexahydrate are dissolved in methanol to form a homogeneous solution and then mixed, thereby promoting the effective coordination of 2-methylimidazole with zinc ions, and then forming ZIF-8 crystals. Methanol solvent is required in the synthesis process to avoid affecting the size and morphology of ZIF-8 crystals.

[0008] In the present invention, the mass ratio of nanozyme to osthole is controlled to ensure the content of osthole in the nanozyme as a carrier. Nanozyme is ZIF-8 formed by zinc ions in zinc nitrate hexahydrate as the coordination center and 2-methylimidazole as the ligand, which belongs to a metal organic framework and has a rhombic dodecahedron morphology. Then, after high-temperature carbonization in a tubular furnace, a nanozyme carrier with biomimetic enzyme activity is obtained. The nanozyme carrier can catalyze the H2O2 generated in situ into ·OH free radicals under the acidic microenvironment of the plant disease site, playing a synergistic bactericidal role. Encapsulating osthole in the nanozyme effectively avoids photodegradation while also avoiding the problem of drug resistance caused by excessive use of antibacterial drugs.

[0009] In another preferred embodiment, the calcination temperature is 600° C. to 800° C., and the calcination time is 2 h to 4 h.

[0010] In another preferred embodiment, the drying temperature is 60° C. to 80° C., and the drying time is 12 h to 24 h.

[0011] In another preferred embodiment, the centrifugal speed is 12000 rpm to 14000 rpm, the number of centrifugation is 1 to 3 times, and the centrifugal time is 10 min to 20 min.

[0012] In another preferred embodiment, the organic agent is ethanol; the mass volume ratio of the osthole to the ethanol is 9 mg-11 mg:1 mL.

[0013] The second aspect of the present invention provides the osthole@nanozyme nanopesticide.

[0014] The third aspect of the present invention provides the use of the osthole@nanozyme nanopesticide in preventing and controlling agricultural diseases.

[0015] In another preferred embodiment, the agricultural disease is an agricultural disease caused by Rhizoctonia solani.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The osthole@nanozyme nanopesticide prepared by the present invention is a plant-derived pesticide osthole loaded with nanozymes. The nanozymes catalyze H2O2 to produce ·OH under acidic conditions at the diseased site, which works together with osthole to play a synergistic antifungal role. Under the action of nanozymes, the problem of slow efficacy of osthole can be effectively solved. At the same time, the antifungal effect can be further improved while reducing the amount of pesticide used, thereby avoiding the problem of drug resistance caused by excessive use of antibacterial drugs.

[0017] The nanozyme in the present invention can separate osthole from the external environment, solves the problem of easy photolysis of osthole, reduces the number of medications, and improves drug stability.

[0018] (2) The nanozyme particles in the present invention are uniform and well dispersed. The average particle size of the nanozyme is between 60nm and 100nm, and the size is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a scanning electron microscope image of the osthole@nanozyme nanopesticide prepared in Example 1.

[0020] Figure 2 This is a statistical diagram of the particle size of OS@ZnSA. In the figure, OS in OS@ZnSA stands for osthole, and ZnSA stands for nanozyme. OS@ZnSA stands for nanozyme loaded with osthole, that is, osthole@nanozyme nanopesticide.

[0021] Figure 3 This is the infrared spectrum of OS@ZnSA in Example 1.

[0022] Figure 4This is the standard curve of osthole.

[0023] Figure 5 This is a diagram of the POD-like enzyme activity of the osthole@nanozyme nanopesticide prepared in Example 1.

[0024] Figure 6 This is the in vitro drug release diagram of the osthole@nanozyme nanopesticide prepared in Example 1.

[0025] Figure 7 These are stability analysis graphs of the osthole@nanozyme nanopesticide prepared in Example 1, wherein A is a graph showing the stability results of OS under ultraviolet light, B is a graph showing the stability results of OS@ZnSA at 0°C, and C is a graph showing the stability results of OS@ZnSA at 54°C.

[0026] Figure 8 Figure 1 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 H2O2, 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 ZnSA and H2O2, g is the in vitro antifungal activity graph of OS@ZnSA, and h is the in vitro antifungal activity graph of OS@ZnSA and H2O2.

[0027] Fig. 9 Biosafety diagram of the nanozyme in Example 1. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the 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.

[0029] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0030] The present invention provides an osthole@nanozyme nanopesticide by utilizing the characteristics of the production of H2O2 and the reduction of pH when the plant parts are infected by the damping-off pathogen. The plant-derived fungicide osthole is loaded with a bionic nanozyme to separate the osthole from the external environment, thereby solving the problem of easy photolysis of plant-derived pesticides, reducing the number of times the drug is used, and improving the stability of the drug. At the same time, the nanozyme can also catalyze H2O2 to produce ·OH under acidic conditions in the diseased part to play a synergistic antifungal role, while reducing the drug and increasing the efficacy, it also avoids the problem of drug resistance caused by excessive use of antibacterial drugs. The osthole@nanozyme nanopesticide has good stability, and the loaded pesticide components are naturally green and harmless to humans, the environment and livestock.

[0031] The room temperature in the embodiments of the present invention is 25±2°C.

[0032] The epidermal cells in the following examples were purchased from Fuheng Biotechnology Co., Ltd.; fetal bovine serum was purchased from CLARKFB15015 superior fetal bovine serum; penicillin / streptomycin was purchased from Sevier Biotechnology Co., Ltd.; DMEM culture medium was purchased from Gibco DMEM high-glucose liquid culture medium; and osthole was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0033] Example 1: A method for preparing osthole@nanozyme nanopesticide.

[0034] S1. Dissolve 10 mmol of zinc nitrate hexahydrate in 100 mL of methanol by ultrasonic method to obtain a zinc nitrate hexahydrate solution, and dissolve 34 mmol of 2-methylimidazole in 100 mL of methanol by ultrasonic method to obtain a 2-methylimidazole solution; mix and stir the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volumes, and stir continuously at room temperature of 25° C. for 5 h, and then centrifuge at 12000 rpm for 15 min. Ultrasonic disperse and centrifuge the solid obtained by centrifugation with methanol for 3 times, and then dry the obtained solid in a vacuum drying oven at 80° C. for 16 h to obtain a dried solid.

[0035] S2. Grind the dried solid into powder and put it into a tube furnace, and calcine it at 800°C for 3 hours to obtain nanozyme.

[0036] S3. Mix the nanozyme and osthole in a mass ratio of 1:5, and dissolve them in ethanol to obtain a mixed solution; wherein the mass volume ratio of osthole to ethanol is 10 mg:1 mL; after the mixed solution is evenly dispersed by ultrasonic, the liquid is evaporated after stirring at room temperature of 25°C for 12 hours, and the sample is washed three times with ethanol and then centrifuged to discard the supernatant, and the retained solid is freeze-dried to obtain osthole@nanozyme nanopesticide.

[0037] Example 2: A method for preparing osthole@nanozyme nanopesticide.

[0038] S1. Dissolve 9 mmol of zinc nitrate hexahydrate in 100 mL of methanol by ultrasonic method to obtain zinc nitrate hexahydrate solution, and dissolve 32 mmol of 2-methylimidazole in 100 mL of methanol by ultrasonic method to obtain 2-methylimidazole solution; mix and stir the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volumes, stir continuously for 4 hours at room temperature of 25°C, and centrifuge at 13000 rpm for 10 minutes. Disperse and centrifuge the solid obtained by centrifugation twice with methanol by ultrasonic method, and then dry the obtained solid in a vacuum drying oven at 60°C for 12 hours to obtain a dried solid.

[0039] S2. Grind the dried solid into powder and put it into a tube furnace, and calcine it at 600°C for 4 hours to obtain nanozyme.

[0040] S3. Dissolve the nanozyme and osthole in ethanol at a mass ratio of 1:4 to obtain a mixed solution, wherein the mass volume ratio of osthole to ethanol is 9 mg:1 mL; after the mixed solution is evenly dispersed by ultrasonic, stir it at room temperature for 6 hours, evaporate the liquid, wash the sample three times with ethanol, centrifuge and discard the supernatant, and obtain osthole@nanozyme nanopesticide after freeze-drying.

[0041] Example 3: A method for preparing osthole@nanozyme nanopesticide.

[0042] S1. Dissolve 11 mmol of zinc nitrate hexahydrate in 100 mL of methanol by ultrasonic method to obtain a zinc nitrate hexahydrate solution, and dissolve 33 mmol of 2-methylimidazole in 100 mL of methanol by ultrasonic method to obtain a 2-methylimidazole solution; mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in equal volumes, stir continuously for 6 hours at room temperature of 25°C, and then centrifuge at 14000 rpm for 20 minutes. Disperse the solid obtained by centrifugation by ultrasonic method with methanol and centrifuge it once, and then dry the obtained solid in a vacuum drying oven at 70°C for 24 hours to obtain a dried solid.

[0043] S2. Grind the dried solid into powder and put it into a tube furnace, and calcine it at 700°C for 2h to obtain nanozyme.

[0044] S3. Dissolve nanozyme and osthole in an ethanol solution at a mass ratio of 1:6 to obtain a mixed solution, wherein the mass volume ratio of osthole to ethanol is 11 mg:1 mL. Ultrasonic disperse the obtained mixed solution evenly, stir it at room temperature for 24 hours, evaporate the liquid, wash the sample three times with ethanol, centrifuge and discard the supernatant, and freeze-dry to obtain osthole@nanozyme nanopesticide.

[0045] 1. Structural characterization.

[0046] Figure 1This is a scanning electron microscope image of the osthole@nanozyme nanopesticide prepared in Example 1. In the following, the osthole@nanozyme nanopesticide is referred to as OS@ZnSA, OS is osthole, and ZnSA represents nanozyme.

[0047] from Figure 1 It can be seen that OS@ZnSA presents a rhombic dodecahedron.

[0048] Figure 2 This is a statistical diagram of the particle size of OS@ZnSA in Example 1. The results show that the average particle size of OS@ZnSA is 81.2nm±5.8nm.

[0049] Figure 3 The infrared spectrum of OS@ZnSA in Example 1 is shown in Figure 1. The sample was qualitatively analyzed by Fourier transform infrared spectroscopy. −1 The characteristic peaks that appeared were attributed to the stretching vibration of the C≡N bond in ZnSA. The OS peak at 1712 cm −1 The stretching vibration of C=O at 1600cm −1 The stretching vibration of aromatic C=C was also observed, which further confirmed that OS was encapsulated in ZnSA.

[0050] 2. Effect of OS@ZnSA.

[0051] Weigh 16 mg of OS in a 20 mL volumetric flask to make a mother solution. Dilute the mother solution into 40 μg / mL, 20 μg / mL, 10 μg / mL, 5 μg / mL, and 2.5 μg / mL standard solutions. Use an ultraviolet spectrophotometer to draw a standard curve with the standard solution concentration as the horizontal axis and the absorbance as the vertical axis, as shown in the figure below: Figure 4 As shown, its standard curve is y=0.0585x+0.0684, R 2 =0.99991. The OS loading rates in Examples 1 to 3 were measured according to the OS standard curve, and the results are shown in Table 1.

[0052] Table 1 Osthole loading rate in Example 1 to Example 3

[0053] Figure 5This is a graph of the POD-like enzyme activity of ZnSA prepared in Example 1. The POD-like enzyme activity of ZnSA was studied using the 3,3',5,5'-tetramethylbenzidine colorimetric method. The POD-like enzyme catalytic performance of ZnSA was determined in acetic acid-sodium acetate buffer at pH 4.0 and 0.1M. All reactions were carried out at 37°C with a reaction time of 5 min. Among them, the H2O2 concentration was 25mM, the TMB concentrations were 1mM, 0.8mM, 0.6mM, 0.4mM, 0.2mM and 0mM, respectively, the ZnSA concentration was 50μg / mL, and the total reaction system was 400μL. The enzymatic kinetics of ZnSA was studied by measuring the absorbance at 652nm, and the Lineweaver-Burk double reciprocal method was used to plot the graph. The results are shown in the figure. Figure 5 The kinetic parameter K of TMB is shown in Figure 2. m and V max 0.1262mM and 4.228μΜ / min respectively. The higher V max and lower K m Its strong catalytic efficiency and suitability as an effective POD mimic were emphasized, indicating that ZnSA possesses excellent POD-like activity.

[0054] Figure 6 The in vitro drug release of OS@ZnSA in Example 1 is shown, and the release behavior of OS@ZnSA under different pH conditions is measured.

[0055] 5 mg of OS@ZnSA sample was dispersed in 50 mL of release medium with a volume ratio of methanol to water of 6:4, and the in vitro release was simulated in a shaker at 25 °C at 120 rpm. 2 mL of release medium was extracted 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, and 336 h, and the same volume of fresh release medium was added to ensure a constant release system. The obtained release medium was centrifuged and filtered with a disposable filter, and the concentration of OS was measured at a wavelength of 323 nm using a UV-visible spectrophotometer. The cumulative release of OS was calculated using the following formula: .

[0056] Among them, OS cumulative release represents the cumulative release of OS, and the unit is %; V e is the volume of release medium obtained in a given time interval, V e =2mL; V 0 is the volume of the released solution,V 0=50mL; C n is the OS concentration in the release medium at that time, in mg / L; m is the total OS mass loaded in ZnSA, in mg.

[0057] The cumulative release behavior of OS@ZnSA at pH 5.0 and 7.0 was studied and monitored by UV-visible spectrophotometer. After 36 hours of treatment, the cumulative release rate of OS@ZnSA at pH 5 was 17.4%, and the cumulative release rate at pH 7 was 16.9%. As time went on, the release slowed down, and the cumulative release rates at the 14th day were 51.0% and 45.6%, respectively, indicating that acidic conditions are more conducive to the release of drugs. After Rhizoctonia solani infects plants, it releases acidic toxic compounds such as phenylacetic acid. The acidic environment of the diseased area is more conducive to the release of active ingredients in nanopesticides.

[0058] The stability of OS loaded in ZnSA nanoparticles and OS raw material under UV exposure was compared. Suspensions of OS@ZnSA and OS containing the same concentration of OS were irradiated with a 36W, 254nm UV lamp at a distance of 10cm from the light source. The UV-visible spectrophotometer was used to monitor the time intervals of 1h, 2h, 4h, 9h, 18h, 28h, 42h, 56h, 70h, 84h, and 96h. The results are shown in Figure 2. Figure 7 As shown in A. Figure 7 It can be seen that after 96 hours of ultraviolet irradiation, the residual rate of OS original drug is only 45.1%, while the residual rate of OS in ZnSA nanocarrier is as high as 96.3%, which shows that ZnSA in the present invention has a good shielding effect on ultraviolet light as a carrier, and can effectively reduce the photodegradation of OS molecules in the aperture. The shielding performance of ZnSA against ultraviolet light may be because it can absorb or reflect most of the ultraviolet light, thereby greatly reducing the exposure of OS to ultraviolet light.

[0059] The storage stability of OS@ZnSA under different temperature conditions was evaluated. Figure 7 As shown in B and C in Figure 1, the OS@ZnSA solution was stored at 0°C for 7 days and 54°C for 14 days, and then the OS content was detected by UV-visible spectrophotometer, and the change in hydrated particle size was measured by dynamic light scattering. The results show that the solution state of the sample is stable and uniform after low-temperature and high-temperature treatment, without obvious precipitation or stratification, and there is no obvious change in the hydrate particle size and OS content of OS@ZnSA during storage.

[0060] Figure 8The in vitro antifungal activity of different pesticides was tested. Acetone and H2O2 were used as solvent controls, and ZnSA, OS, OS@ZnSA, ZnSA and H2O2, and OS@ZnSA and H2O2 were used as experimental groups. The mycelial growth rate method was used to determine the antifungal activity of OS@ZnSA against Rhizoctonia solani. Among them, the effective concentration of OS was maintained at 250 μg / mL.

[0061] Under sterile conditions, 6 mm diameter Rhizoctonia solani cakes were inoculated in the center of potato dextrose agar culture dishes containing the above concentration reagents. After culturing at 25°C in the dark for 4 days, the colony diameters were measured by the cross method, and the relative inhibition rate against Rhizoctonia solani was calculated. The test was performed in triplicate. The results are as follows: Figure 8 shown.

[0062] During the growth process, Rhizoctonia solani continuously secretes organic acids, and acidic conditions are conducive to the POD enzyme activity of ZnSA. Figure 8 As shown in Figure d, ZnSA itself has no inhibitory effect on the growth of Rhizoctonia solani, and the mycelium diameter is not significantly different from that of the control group. Figure 8 As shown in Figure f, when ZnSA combines with H2O2, it will instantly catalyze H2O2 to produce ·OH, causing the fungal membrane structure to be destroyed and inactivated, and its antibacterial effect reached 53.81%. Figure 8 As shown in Figures e and g, when the concentration of OS was 250 μg / mL, the antibacterial rate of OS@ZnSA was 53.47%, which was slightly lower than the 65.26% antibacterial rate of OS original drug. This may be because ZnSA as a carrier allows OS to be released slowly and for a long time. Figure 8 As shown in Figures e and h, OS@ZnSA and H2O2 showed better inhibitory effects on Rhizoctonia solani on PDA plates, with an inhibition rate of 90.6%, indicating that ZnSA and OS in the nanopesticides have a synergistic effect.

[0063] Fig. 9 The biosafety of OS@ZnSA prepared in Example 1 is shown. In actual application, the degradation of ZnSA will release various elements, so environmental safety is an important evaluation indicator. The biosafety of ZnSA was evaluated using human epidermal cells. Human epidermal cells HaCat in the logarithmic growth phase were inoculated on a 96-well plate and cultured at 37°C in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and 1% penicillin / streptomycin for 24 hours. The original culture medium was discarded and a drug-containing culture medium with a concentration of 250 μg / mL nanoparticles was added for 24 hours. The cell viability was determined by the MTT method. Fig. 9 It can be seen that the nanocarrier has no obvious toxic effect on the growth of HaCat cells, indicating that the ZnSA nanocarrier has good biocompatibility and environmental safety.

[0064] The above are only 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 a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing osthole@nanozyme nanopesticide, characterized in that: The following steps are involved: The nanozyme and osthole are mixed and reacted in an organic reagent environment for 6 hours to 24 hours to load the osthole on the nanozyme, and then washed, centrifuged to obtain the precipitate, and dried to obtain the osthole@nanozyme nanopesticide; 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 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 9mmol~11mmol:100mL; 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 method for preparing 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 method for preparing 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 method for preparing 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.

5. The method for preparing osthole@nanozyme nanopesticide according to claim 1, characterized in that: The organic reagent is ethanol; the mass volume ratio of the osthole to the ethanol is 9 mg-11 mg:1 mL.

6. An osthole@nanozyme nanopesticide prepared by the method for preparing the osthole@nanozyme nanopesticide according to any one of claims 1 to 5.

7. Use of the osthole@nanozyme nanopesticide according to claim 6 in preventing and controlling agricultural diseases.

8. The use according to claim 7, characterized in that: The agricultural diseases are agricultural diseases caused by Rhizoctonia solani.

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