Multifunctional hollow copper sulphide nano pesticide fertilizer as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pesticides, and particularly relates to a multifunctional hollow copper sulphide nano pesticide fertilizer as well as a preparation method and application thereof. A drug is loaded by a hollow structure of nano hollow copper sulphide, and the surface of the drug is coated with oxygen carboxymethyl chitosan through chemical crosslinking, so that encapsulation and slow-controlled release of tebuconazole are realized, and meanwhile, the deposition of the pesticide on the surface of a plant is improved. When bacteria are infected, organic acid can be released, so that pH is reduced, coordinate bonds are broken, and drugs and copper sulphide molecules are slowly released, the effects of continuously sterilizing and slowly providing copper fertilizer and sulfur fertilizer are achieved, stability is kept in a normal state, and pollution to the environment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and particularly relates to a preparation method and application of a hollow copper sulfide nanoparticle fertilizer. Background Art

[0002] Pesticides play an important role in preventing and controlling crop diseases, pests and weeds and ensuring food production and safety. However, traditional pesticide preparations have problems such as coarse particle size, low utilization rate and serious harm to the ecological environment. In recent years, with the development of nanotechnology, the use of nanotechnology to develop intelligent sustained-release drug delivery systems can improve the effective utilization rate of pesticides, reduce the frequency of application, reduce agricultural input costs, and improve environmental problems, providing guarantees for the development of sustainable green agriculture. Copper fungicides have the advantages of a wide range of bactericidal effects, long-term persistence and low resistance. They play an important role in protecting crops from bacterial and fungal diseases and have been widely used in agricultural production. However, long-term and frequent use of copper fungicides may pose potential risks to the safe production of crops and the ecological environment. The long-term accumulation of traditional copper fungicides may change the physiological state of various organisms in the environment, leading to plant nutrient loss, reduced active products and other problems. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a multifunctional hollow copper sulfide nano-fertilizer and a preparation method and application thereof. The multifunctional hollow copper sulfide nano-fertilizer can not only be delivered and released in a targeted manner in the plant body, so that copper sulfide and tebuconazole are released in large quantities at the site of pathogen damage, giving full play to the synergistic antibacterial effect of the two, effectively avoiding the generation of drug-resistant strains, but also can release the essential elements required for plant growth and enhance the plant's own resistance.

[0004] Specifically, the copper in copper sulfide is more stable after sulfidation, releases copper ions more slowly, and has better biocompatibility. As a new type of inorganic material, copper sulfide has a higher photothermal conversion efficiency. Under the irradiation of visible light to near-infrared light, the slowly released copper ions can undergo redox reactions with the buffer matrix around the diseased tissue to produce reactive oxygen species for photodynamic sterilization. Compared with traditional photothermal materials, hollow copper sulfide carriers have cavities, high surface areas, and superior chemical stability in addition to good photothermal effects, which can ensure that they have a greater load capacity to transport pesticides. Copper and sulfur are both essential nutrients for plants. Copper is involved in the composition of the electron transfer system in plants and is the active center of a variety of enzymes. Sulfur is an important component of plant proteins and amino acids, a component of a variety of coenzymes and vitamins, and an important component of chlorophyll. When the hollow copper sulfide framework slowly degrades and releases copper and sulfur ions, it can promote plant growth. It can be seen that the multifunctional carrier of hollow copper sulfide nanomaterials has broad application prospects in agriculture and can be used to transport pesticides and supplement plant nutrition.

[0005] Chitosan is a naturally occurring polymer with remarkable biocompatibility and functional properties, and has broad prospects for application in the field of pesticides. Chitosan is a natural compound present in pathogenic fungi. Chitin plays an important protective role in the colonization of pathogenic fungi, but it can be broken down by chitinase in plants. In order to avoid the destruction of the cell wall of fungal pathogens by the action of plant chitinase, some fungal pathogens can convert their cell wall chitin into chitosan when infecting plant tissues. Fungal cell walls are composed of a variety of polysaccharides, including chitin and chitosan. This facilitates the penetration of chitosan-based nanoparticles into these cells. Oxycarboxymethyl chitosan is a pH-sensitive amphoteric polysaccharide with better water solubility than chitosan, better antibacterial, antitumor, antioxidant, antifungal and other functions, as well as good biocompatibility and adhesion, and has broad application prospects in the field of drug delivery.

[0006] The present invention combines nanotechnology with bionics, takes tebuconazole, a fungicide with high efficiency, systemicity and broad spectrum but poor water dispersibility, as a model pesticide, and grafts oxycarboxymethyl chitosan based on hollow copper sulfide as a carrier to prepare a pH-responsive multifunctional nano-fertilizer suitable for foliar spraying of plants.

[0007] The first technical purpose of the present invention is to provide a multifunctional hollow copper sulfide nano-fertilizer, comprising a drug carrier and a drug active ingredient simultaneously loaded on the carrier; the drug carrier comprises hollow copper sulfide containing a small amount of polyvinyl pyrrolidone and oxycarboxymethyl chitosan; the drug active ingredient is a bactericide.

[0008] Optionally, the components of the multifunctional hollow copper sulfide nano-fertilizer are, by mass percentage, 5%-15% polyvinyl pyrrolidone, 30%-60% hollow copper sulfide, 10%-40% fungicide, and 5%-15% oxycarboxymethyl chitosan.

[0009] Optionally, the fungicide is tebuconazole.

[0010] Optionally, the average molecular weight of the polyvinyl pyrrolidone is 58,000, and its function is to stabilize the structure of the nano hollow copper sulfide. The carboxylation degree of the oxycarboxymethyl chitosan is ≥ 80%, and its function is to wrap the hollow copper sulfide containing the drug and control the release of the drug.

[0011] The multifunctional hollow copper sulfide nano-fertilizer disclosed by the invention has good mechanical properties, dispersibility and biocompatibility.

[0012] Furthermore, the copper sulfide and tebuconazole in the multifunctional hollow copper sulfide nano-fertilizer are gradually released along with the expansion or fracture of the surface oxygen carboxymethyl chitosan, and have a certain sustained release ability.

[0013] The second technical purpose of the present invention is to provide a method for preparing the multifunctional hollow copper sulfide nano-fertilizer, comprising the following steps:

[0014] S1: Weigh the sample according to the following mass percentages: 40-50% polyvinyl pyrrolidone, 3-8% copper chloride dihydrate, 2-7% hydrazine hydrate, and 35-45% sodium sulfide nonahydrate; first dissolve polyvinyl pyrrolidone in 100 mL pure water, and stir at room temperature to dissolve into a solution; then add copper sulfide dihydrate and 100 mL sodium hydroxide aqueous solution with a pH of 9; add hydrazine hydrate dropwise to the mixed solution, stir evenly, and then quickly add a pure aqueous solution of sodium sulfide; heat and stir the solution in a water / oil bath, wash with pure water, and freeze-dry to obtain a hollow copper sulfide;

[0015] S2: mixing a methanol / water solution of hollow copper sulfide and a methanol solution of tebuconazole, and centrifugally drying the mixture to obtain a hollow copper sulfide loaded with a drug;

[0016] S3: Disperse oxycarboxymethyl chitosan in pure water, then add a hollow copper sulfide aqueous solution loaded with drugs, and centrifuge and dry to obtain a multifunctional hollow copper sulfide nano-fertilizer.

[0017] Optionally, in step S1, the stirring rate is 300 rpm-600 rpm, the heating temperature is 50° C.-90° C., and the heating time is 2 hours-6 hours.

[0018] Optionally, in step S2, a methanol / water (V:V=1:1) solution containing 100 mg of hollow copper sulfide and a methanol solution of tebuconazole are mixed at a mass percentage of 1:0.5-4 of the active ingredients; in step S3, 50 mL of an aqueous solution of oxycarboxymethyl chitosan and 50 mL of an aqueous solution of 100 mg of hollow copper sulfide loaded with drugs are mixed at a mass percentage of 0.2-2:1 of the active ingredients.

[0019] Optionally, in steps S2 and S3, the mixing conditions are room temperature and protected from light, the stirring rate is 300rpm-600rpm, the centrifugation conditions in steps S1, S2 and S3 are 8000rpm-12000rpm, 3 minutes-10 minutes, and the drying is freeze-vacuum drying, the conditions are -50°C, 2 hours-8 hours.

[0020] The third technical purpose of the present invention is to provide the application of the multifunctional hollow copper sulfide nano-fertilizer in plant disease and insect pest control.

[0021] Specifically, the multifunctional hollow copper sulfide nano-fertilizer is used during bacterial infection.

[0022] Furthermore, the plant disease is at least one of fusarium head blight, rust, powdery mildew, sheath blight, smut, take-all disease, root rot, and stem base rot.

[0023] Furthermore, the multifunctional hollow copper sulfide nano-fertilizer has a better inhibitory effect on pathogens than commercial drugs when the concentration of the active ingredients of the drug is the same, and is not easy to induce drug resistance in the bacteria.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] The multifunctional hollow copper sulfide nano-fertilizer prepared by the present invention has a particle size of nanometer level, has good penetration effect, has good antibacterial effect, and is not easy to produce drug resistance. Compared with commercial drugs of the same concentration, it shows better inhibitory activity against plant pathogens; moreover, the coating of oxycarboxymethyl chitosan can effectively increase the dispersion effect of nano-fertilizer in water, improve biocompatibility and bioadhesion, and has a slow-release control function. Copper sulfide can enhance the killing and inhibitory effect of fungicides on pathogens through photothermal effect and the generation of active oxygen, reduce the amount of pesticides used, and can slowly provide plants with essential elements, promote growth and improve disease resistance. Therefore, the multifunctional hollow copper sulfide nano-fertilizer has broad development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 The scanning electron microscope (SEM) image and particle size distribution diagram of the multifunctional hollow copper sulfide nano-fertilizer;

[0028] Figure 2 is the standard curve of tebuconazole in high performance liquid chromatography (HPLC);

[0029] Figure 3 This is the cumulative release graph of tebuconazole from the multifunctional hollow copper sulfide nano-fertilizer under different pH conditions;

[0030] Figure 4 This is a graph showing the indoor antibacterial activity of the multifunctional hollow copper sulfide nano-fertilizer against Fusarium graminearum for 3 days. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0033] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0034] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0035] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0036] The invention discloses a multifunctional hollow copper sulfide nano-fertilizer and a preparation method and application thereof.

[0037] The present invention, the preparation steps of hollow copper sulfide are:

[0038] The sample was weighed according to the following mass / volume: 1.29 g of polyvinyl pyrrolidone, 86 mg of cupric chloride dihydrate, 128 μL of hydrazine hydrate, and 1.20 g of sodium sulfide nonahydrate; firstly, polyvinyl pyrrolidone was dissolved in 100 mL of pure water, and dissolved into a solution by stirring at room temperature; then, copper sulfide dihydrate and 100 mL of sodium hydroxide aqueous solution with a pH of 9 were added; hydrazine hydrate was added dropwise to the mixed solution, and after stirring evenly, a pure aqueous solution of sodium sulfide was quickly added; the solution was heated and stirred at 75° C. in a water / oil bath for 4 hours, centrifuged at 10,000 rpm for 5 minutes, and then washed with pure water until the supernatant was colorless, and freeze-dried for 6 hours at a vacuum degree of 1 Pa at -50° C. using a freeze dryer to obtain a hollow copper sulfide.

[0039] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0040] Example 1

[0041] Weigh 100 mg of hollow copper sulfide and 200 mg of tebuconazole original drug, first disperse the hollow copper sulfide in a mixed solution of 100 mL of methanol and water (v / v=1:1), ultrasonicate for 10 minutes to fully disperse it, and stir it at room temperature with magnetic stirring at 500 rpm. Dissolve the tebuconazole original drug in 2 mL of methanol solution, ultrasonicate for 2 minutes to fully dissolve it, slowly add it to the hollow copper sulfide solution, and stir for 24 hours in the dark. Centrifuge at 10000 rpm for 3 minutes, wash three times with pure water, freeze-dry at -50 ° C for 3 hours to obtain a hollow copper sulfide-loaded tebuconazole nanocomposite system, that is, a drug-loaded hollow copper sulfide.

[0042] Weigh 100 mg of oxycarboxymethyl chitosan and disperse it in 50 mL of pure water. Stir at 300 rpm for 1 hour at a constant temperature of 30 ° C to fully dissolve it. Disperse 100 mg of drug-loaded hollow copper sulfide in 50 mL of pure water and fully disperse it by ultrasonication for 10 minutes, slowly add it to the oxycarboxymethyl chitosan solution and mix it for 1 hour. Under continuous magnetic stirring, 5 mL of sodium tripolyphosphate solution with a concentration of 8 mg / mL is slowly dripped into the mixed system, and the cross-linking reaction is carried out for 2 hours. The reacted solution is centrifuged at 10000 rpm for 5 minutes, washed three times with pure water, and freeze-dried for 5 hours at a vacuum degree of 1 Pa at -50 ° C using a freeze dryer to obtain a multifunctional hollow copper sulfide nanomedicine fertilizer.

[0043] Example 2

[0044] Weigh 100 mg of hollow copper sulfide and 200 mg of tebuconazole original drug, first disperse the hollow copper sulfide in a mixed solution of 100 mL of methanol and water (v / v=1:1), ultrasonicate for 10 minutes to fully disperse it, and stir it at room temperature with magnetic stirring at 500 rpm. Dissolve the tebuconazole original drug in 2 mL of methanol solution, ultrasonicate for 2 minutes to fully dissolve it, slowly add it to the hollow copper sulfide solution, and stir for 24 hours in the dark. Centrifuge at 10000 rpm for 3 minutes, wash three times with pure water, freeze-dry at -50 ° C for 3 hours to obtain a hollow copper sulfide-loaded tebuconazole nanocomposite system, that is, a drug-loaded hollow copper sulfide.

[0045] Weigh 100mg oxygen carboxymethyl chitosan and disperse it in 50mL pure water, stir at 300rpm for 1 hour at 30℃ constant temperature to fully dissolve it. 100mg drug-loaded hollow copper sulfide is dispersed in 50mL pure water and fully dispersed by ultrasound for 10 minutes, slowly added to the oxygen carboxymethyl chitosan solution and mixed for 1 hour. Under continuous magnetic stirring, 6mL 0.5% glutaraldehyde solution is slowly dripped into the mixed system, and the cross-linking reaction is carried out for 2 hours. The reacted solution is centrifuged at 10000rpm for 5min, washed three times with pure water, and freeze-dried for 5 hours at -50℃ vacuum degree 1Pa using a freeze dryer to obtain a multifunctional hollow copper sulfide nano drug fertilizer.

[0046] Example 3

[0047] Weigh 100 mg of hollow copper sulfide and 200 mg of tebuconazole original drug, first disperse the hollow copper sulfide in a mixed solution of 100 mL of methanol and water (v / v=1:1), ultrasonicate for 10 minutes to fully disperse it, and stir it at room temperature with magnetic stirring at 500 rpm. Dissolve the tebuconazole original drug in 2 mL of methanol solution, ultrasonicate for 2 minutes to fully dissolve it, slowly add it to the hollow copper sulfide solution, and stir for 24 hours in the dark. Centrifuge at 10000 rpm for 3 minutes, wash three times with pure water, freeze-dry at -50 ° C for 3 hours to obtain a hollow copper sulfide-loaded tebuconazole nanocomposite system, that is, a drug-loaded hollow copper sulfide.

[0048] Weigh 100mg of oxygen carboxymethyl chitosan and disperse it in 50mL pure water, stir at 300rpm for 1 hour at a constant temperature of 30°C to fully dissolve it, then add 191.7mg 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and continue stirring for 30 minutes. 100mg of drug-loaded hollow copper sulfide is dispersed in 50mL pure water and fully dispersed by ultrasound for 10 minutes, slowly added to the oxygen carboxymethyl chitosan solution and mixed for 30 minutes. Under continuous magnetic stirring, 115.1mg N-hydroxysuccinimide is added to the mixed system, and the cross-linking reaction is carried out for 2 hours. The reacted solution is centrifuged at 10000rpm for 5min, washed three times with pure water, and freeze-dried for 5 hours at a vacuum degree of 1Pa at -50°C using a freeze dryer to obtain a multifunctional hollow copper sulfide nanomedicine fertilizer.

[0049] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following experiments are conducted to further illustrate the technical features disclosed in the present invention, but they should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above invention without inventive work are also deemed to fall within the scope of protection of the present invention.

[0050] (1) The shape, size, and dispersion of the multifunctional hollow copper sulfide nanoparticle fertilizer provided in Example 1 were characterized by scanning electron microscopy (SEM), and the particle size of the image was measured using ImageJ software to obtain a particle size distribution diagram. The results are shown in Figure 1 .

[0051] from Figure 1 The two electron microscope images on the left and right show that the prepared multifunctional hollow copper sulfide nano-fertilizer has a hollow structure, consistent morphology, small and uniform particle size, and a size of 125.38±18.54nm (see Figure 1 Particle size distribution diagram on the right).

[0052] (2) Determination of the drug loading rate of multifunctional hollow copper sulfide nanofertilizer

[0053] Weigh 5.0 mg of dried multifunctional hollow copper sulfide nano-fertilizer into a beaker, add 10 mL of methanol, perform ultrasonic extraction for 2 hours, centrifuge at 10000 rpm for 5 minutes, take 1 mL of supernatant and inject it into a brown volumetric flask through a 0.22 μm filter membrane, and detect it by high performance liquid chromatography (HPLC). Detection conditions: mobile phase: methanol: water = 70:30, injection volume V = 10 μL, wavelength 220 nm, column temperature 30 ° C, chromatographic column XDB-C18, retention time about 6 minutes. According to Figure 2 According to the standard curve of , the drug loading amount of tebuconazole in the multifunctional hollow copper sulfide nano-fertilizer provided in Example 1 is 28.66%.

[0054] (3) Determination of the cumulative drug release rate of multifunctional hollow copper sulfide nanofertilizer in different pH environments

[0055] 5.0 mg of the dried multifunctional hollow copper sulfide nano-fertilizer provided in Example 1 was weighed into a dialysis bag (molecular weight cutoff of 8,000-12,000 Da), and then placed in a beaker containing 100 mL of a methanol-water mixture (20:80, v / v) as a release medium. The pH of the medium was adjusted to 4.0, 7.0 and 10.0 using hydrochloric acid and sodium hydroxide solutions to simulate the release effect under acidic, neutral and alkaline conditions. Each treatment was repeated three times, and the beaker was placed on a nine-link magnetic stirrer at a speed of 100 rpm and stirred continuously at room temperature. Figure 3 It can be seen that the release effect of tebuconazole is different under different pH conditions. The release amount under acidic conditions is greater than that under alkaline conditions and greater than that under neutral conditions. Under acidic conditions, the carboxyl groups will be protonated, which weakens the reaction activity and leads to the destruction of the cross-linking structure, resulting in a large amount of drug release. Under alkaline conditions, the ester bonds are easily hydrolyzed, resulting in the destruction of the cross-linking structure, but the release effect is slightly weaker than that under acidic conditions.

[0056] (4) Figure 4The multifunctional hollow copper sulfide nano-fertilizer provided in Example 1 has bactericidal activity against Fusarium graminearum, the pathogenic bacteria of wheat stem base rot. According to the results of the mycelium growth rate determination method, when the effective content of the active ingredient tebuconazole is 0.01 mg / L, the plate treated with the multifunctional hollow copper sulfide nano-fertilizer has a stronger effect on mycelium growth inhibition than the commercial drug treatment. The inhibition rate increased by 5.6% by precise measurement and calculation using a vernier caliper. The data show that the multifunctional hollow copper sulfide nano-fertilizer has a better inhibitory effect on the pathogen than the equivalent commercial drug. It may be that the nano-fertilizer particles have a smaller particle size and better contact with the mycelium, and the hollow copper sulfide carrier can synergistically resist bacteria by destroying the cell membrane and other means, thereby achieving a better antibacterial effect.

[0057] In order to further test the efficacy of the multifunctional hollow copper sulfide nano-fertilizer on wheat stem base rot, the multifunctional hollow copper sulfide nano-fertilizer provided in Examples 1-3 and Comparative Example 1 (430 g / L tebuconazole suspension) and Comparative Example 2 (water) were used for field control of wheat stem base rot.

[0058] The test site was selected in a farmer's field in Dengfeng City, Henan Province. The soil type is typical tidal soil with good ventilation and water permeability, uniform soil fertility, and convenient transportation. Wheat and summer corn have been planted continuously for many years, and the incidence of wheat stem rot is relatively serious. During the wheat greening period, the stems and leaves are sprayed for prevention and control.

[0059] Each example and the commercial drug control were sprayed evenly at 5 g / mu of the active ingredient of the drug. The soil, cultivation, water and fertilizer management conditions of each treatment group were completely the same.

[0060] On the 7th and 30th days after spraying, the control effect of each embodiment on wheat stem base rot was investigated respectively.

[0061] The calculation method of the control effect is obtained by the following formula:

[0062]

[0063]

[0064] The experimental results of the control effect are shown in Table 1.

[0065] Table 1 Wheat stem rot control effect results

[0066] Group 7d disease index 7d control effect (%) 30-day disease index 30d control effect (%) Example 1 5.22 66.82％ 6.14 66.36％ Example 2 5.08 67.71％ 6.00 67.12％ Example 3 4.92 68.72％ 5.93 67.51％ Comparative Example 1 6.54 58.42％ 8.34 54.30％ Comparative Example 2 15.73 — 18.25 —

[0067] The above field test results show that the multifunctional hollow copper sulfide nano-fertilizer of the present invention is sprayed during the crop greening period. Compared with the control example, it has a higher prevention and control effect on wheat stem base rot and a longer duration of effect.

[0068] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multifunctional hollow copper sulfide nano-fertilizer, characterized in that: The multifunctional hollow copper sulfide nano-medicinal fertilizer comprises a drug carrier and a drug active component simultaneously loaded on the carrier; the drug carrier comprises hollow copper sulfide containing a small amount of polyvinyl pyrrolidone and oxycarboxymethyl chitosan; and the drug active component is a bactericide.

2. The multifunctional hollow copper sulfide nano-fertilizer according to claim 1, characterized in that: Calculated by mass percentage, the components of the multifunctional hollow copper sulfide nano-fertilizer are: 5%-15% of polyvinyl pyrrolidone, 30%-60% of hollow copper sulfide, 10%-40% of bactericide, and 5%-15% of oxycarboxymethyl chitosan.

3. The multifunctional hollow copper sulfide nano-fertilizer according to claim 1, characterized in that: The fungicide is tebuconazole.

4. The multifunctional hollow copper sulfide nano-fertilizer according to claim 2, characterized in that: The average molecular weight of the polyvinyl pyrrolidone is 58,000, and the carboxylation degree of the oxycarboxymethyl chitosan is ≥80%.

5. The multifunctional hollow copper sulfide nano-fertilizer according to claim 1, characterized in that: The particle size of the multifunctional hollow copper sulfide nano-fertilizer is 100-200nm.

6. A method for preparing the multifunctional hollow copper sulfide nano-fertilizer according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: polyvinyl pyrrolidone, copper chloride, hydrazine hydrate and sodium sulfide are used as raw materials, and then subjected to hydrothermal reaction and centrifugal drying to obtain hollow copper sulfide for later use; S2: mixing the methanol / water solution of the hollow copper sulfide prepared in step S1 and the methanol solution of tebuconazole, and centrifugally drying them to obtain the hollow copper sulfide loaded with the drug; S3: dispersing oxygen carboxymethyl chitosan in pure water, then adding the drug-loaded hollow copper sulfide prepared in step S2, mixing, and centrifugally drying to obtain the multifunctional hollow copper sulfide nano-medicine fertilizer.

7. The preparation method according to claim 6, characterized in that: In step S1, the temperature of the hydrothermal reaction is 50° C.-90° C., and the time is 2-6 hours.

8. The preparation method according to claim 6, characterized in that: The mixing conditions in steps S2 and S3 are room temperature and light-proof, and the stirring rate is 300rpm-600rpm. The centrifugation conditions in steps S1, S2 and S3 are 8000-12000rpm, 3-10 minutes, and the drying is freeze-vacuum drying at a temperature of -50°C for 2-8 hours.

9. Use of the multifunctional hollow copper sulfide nano-fertilizer as claimed in any one of claims 1 to 5 or the multifunctional hollow copper sulfide nano-fertilizer as claimed in claim 6 in controlling plant diseases and insect pests.

10. The use according to claim 9, characterized in that: The plant disease is at least one of fusarium head blight, rust, powdery mildew, sheath blight, smut, take-all disease, root rot and stem base rot.

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