Fluazinam nano-pesticide with pH and enzyme dual stimulation response controlled release as well as preparation method and application of fluazinam nano-pesticide

Abstract

The invention discloses a pH and enzyme dual stimulation response controlled release fluazinam nano-pesticide as well as preparation and application thereof. The nano-pesticide comprises a carrier, a fluazinam active compound and pectin, the carrier is a zinc-based metal organic framework material ZIF-8, fluazinam active compound is added into a raw material for preparing the ZIF-8, and fluazinam is loaded on the ZIF-8 in situ; the pectin is coated on the surface of the ZIF-8 loaded with the fluazinam active compound through a connecting agent; the preparation method comprises the following steps: (1) adding a ligand, a zinc salt, an end-capping reagent and a fluazinam active compound into a solvent, and synthesizing ZIF-8 loaded with the fluazinam active compound through a one-pot method; and (2) adding a coupling agent into a solvent, then adding ZIF-8 loaded with fluazinam active compound, and finally adding pectin. The fluazinam nano-pesticide has pH and enzyme dual stimulation response controlled release performance, burst release is avoided, the utilization rate of the pesticide is increased, and the water dispersion stability, the biocompatibility and the target adhesiveness are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nano-pesticides, in particular to a pH and enzyme dual stimulus response controlled release fluazinam nano-pesticide, and a preparation method and application thereof. BACKGROUND

[0002] Chemical pesticides, as the core production materials to ensure global food security, play an irreplaceable role in agricultural production. Fluazinam, as a dinitroaniline fungicide, has the characteristics of broad-spectrum and high efficiency, and is very effective against Alternaria, Phytophthora and other fungi.

[0003] Traditional fluazinam preparations are mainly in the form of suspensions and wettable powders, which have the disadvantages of easy burst release, low utilization rate, etc. Therefore, it is an urgent need to develop new fluazinam preparations that are efficient, stable, safe and environmentally friendly. SUMMARY

[0004] The first object of the present application is to provide a pH and enzyme response controlled release fluazinam nano-pesticide, which avoids burst release of fluazinam and improves the utilization rate of fluazinam. The second object of the present application is to provide a preparation method of the pH and enzyme response controlled release fluazinam nano-pesticide. The third object of the present application is to provide an application of the pH and enzyme response controlled release fluazinam nano-pesticide in the prevention and treatment of tobacco brown spot.

[0005] The pH and enzyme dual stimulus response controlled release fluazinam nano-pesticide comprises a carrier, fluazinam technical material and pectin. The carrier is zinc-based metal organic framework material ZIF-8, and the fluazinam technical material is added to the raw material for preparing ZIF-8, and the fluazinam is loaded in situ on the ZIF-8. The pectin is wrapped on the surface of the ZIF-8 loaded with the fluazinam technical material through a linking agent, one end of the linking agent is connected with the ZIF-8, and the other end is connected with the pectin.

[0006] Preferably, the molar ratio of zinc ions to fluazinam technical material in the raw material of ZIF-8 is 8500:(1-2). During the formation of ZIF-8, the fluazinam technical material participates in the coordination process of Zn 2+ , thereby mainly affecting the drug loading capacity, particle size, void and other morphology parameters of the nano-pesticide.

[0007] Preferably, the mass ratio of the ZIF-8 loaded with the fluazinam technical material to the pectin is 2:(1-2). The ratio of the two has an influence on the slow release and fungicidal performance of the nano-pesticide. With the increase of the ratio of pectin, the fungicidal effect gradually decreases, and the optimal ratio is 1:1.

[0008] Preferably, the linking agent is a silane coupling agent, one end of the silane coupling agent is connected with the metal sites on the surface of the ZIF-8 through a coordination reaction, and the other end is connected with the carboxyl group of the pectin through a condensation reaction.

[0009] The preparation method of the pH and enzyme-responsive controlled-release fluazinam nanopesticide of the present invention includes the following steps:

[0010] (1) The ligand, zinc salt, capping agent and fluazinam technical of zinc-based metal-organic framework material ZIF-8 were added to the solvent and ZIF-8 loaded with fluazinam technical was synthesized by one pot method.

[0011] (2) Add a linker to the solvent, and then add the ZIF-8 loaded with fluazinam technical prepared in step (1), so that the linker first connects with ZIF-8, and then add pectin to connect the linker with pectin, so that the pectin coats the surface of ZIF-8 loaded with fluazinam technical.

[0012] Preferably, in step (1), the ligand of ZIF-8 is dimethylimidazole.

[0013] Preferably, in step (1), the capping agent is hexadecyltrimethylammonium bromide.

[0014] Preferably, in step (1), the solvent is an aqueous ethanol solution with a volume fraction of 20%.

[0015] Preferably, in step (2), the linker is a silane coupling agent, and the reaction temperature of the silane coupling agent with ZIF-8 or pectin is 20-30°C, and the reaction time is 12-24 hours.

[0016] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane (KH-550), and the mass ratio of the silane coupling agent to the zinc-based metal-organic framework material loaded with fluazinam is (1-3):3000. This ratio affects the morphology and controlled-release properties of the subsequently prepared nanopesticides. As the proportion of the silane coupling agent increases, the particle size of the pectin-coated nanopesticides becomes larger, with a ratio of 1:1000 being optimal.

[0017] Preferably, in step (2), the solvent is deionized water.

[0018] The application of the pH and enzyme-responsive controlled-release fluazinam nanopesticide described in this invention in the prevention and control of tobacco red spot disease.

[0019] Invention Mechanism:

[0020] This invention relates to a pH- and enzyme-responsive controlled-release nanopesticide containing fluazinam. Using ZIF-8 as a carrier, the fluazinam technical is generated in situ on the surface and interior of ZIF-8, and then pectin is coated onto the surface of the fluazinam-loaded ZIF-8. Leveraging the advantages of the zinc-based organometallic framework ZIF-8, such as its large specific surface area, high porosity, good stability, simple preparation, and acid sensitivity, loading fluazinam improves its stability and utilization, reducing off-target losses. Compared to materials containing heavy metals such as zirconium, chromium, and copper, ZIF-8 also exhibits good biocompatibility. After degradation, Zn serves as an essential trace element for plant growth, and the imidazole group is an important component of plant histidine. Pectin, a natural polysaccharide, can enhance the dispersion stability of nanomaterials in water and improve their safety when modified onto the nanomaterial surface. Furthermore, pectin exhibits enzyme-responsive controlled-release properties in the presence of pectinase, making it suitable for the controlled release of pesticides. When pathogenic fungi infect tobacco, they secrete degrading enzymes such as pectinase and acidic substances, which degrade the tobacco cell wall, thereby further infecting plant tissues. Therefore, this invention utilizes the pectinase secreted by the pathogenic fungi during tobacco cell infection as the first stimulus response; the pectinase dissolves the pectin, allowing fluazinam loaded on the ZIF-8 surface to be precisely released at the site of plant tissue damage. The acidic substances secreted by the pathogenic fungi during infection cause the ZIF-8 to collapse, further releasing fluazinam. Furthermore, the fluazinam nanopesticide of this invention utilizes Zn... 2+ Its own bactericidal function, combined with fluazinam, has a synergistic effect, jointly inhibiting the growth of Alternaria alternata and effectively controlling the spread of tobacco scab.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The fluazinam nanopesticide of the present invention has pH and enzyme dual stimulation response controlled release performance, which can accurately control the release of pesticides under the action of exogenous stimulation, avoid burst release, effectively improve the utilization rate of pesticides, and reduce the amount of pesticides used; (2) The fluazinam nanopesticide of the present invention has good water dispersion stability and target adhesion, which further improves the utilization rate of pesticides; (3) The fluazinam nanopesticide of the present invention has good biocompatibility; (4) It has excellent characteristics such as simple preparation process, wide range of use, high efficiency, low environmental pollution, simple operation, and high economic benefits. Attached Figure Description

[0022] Figure 1 SEM images of the pH and enzyme-responsive controlled-release nanopesticides prepared in Examples 1-4 and the materials in Comparative Examples 3 and 4;

[0023] Figure 2 FT-IR spectra of the pH and enzyme dual-stimulation responsive controlled-release nanopesticide prepared in Example 1 and the materials of Comparative Examples 1-4;

[0024] Figure 3 Thermoanalytical diagrams of the pH and enzyme dual-stimulation responsive controlled-release nanopesticide prepared in Example 1 and the materials of Comparative Examples 1-3 are shown.

[0025] Figure 4 The controlled release of the pH and enzyme-dependent enzyme-stimulated nanopesticide prepared in Example 1 was tested under different pH conditions and at pH=7 with the addition of pectinase.

[0026] Figure 5 Water contact angle diagrams of the pH and enzyme dual-stimulation responsive controlled-release nanopesticide prepared in Example 1 and the technical grade pesticide in Comparative Example 1;

[0027] Figure 6 The pH and enzyme dual-stimulation responsive controlled-release nanopesticide prepared in Example 1 and the technical grade pesticide of Comparative Example 1 were sprayed on tobacco leaves, and the inverted fluorescence microscope images were compared before and after simulated rain washing under bright field and dark field conditions.

[0028] Figure 7 Zeta potential data test graphs for the pH and enzyme dual-stimulation responsive controlled-release nanopesticide prepared in Example 1 and the materials of Comparative Examples 1-4;

[0029] Figure 8 The graph shows the inhibition of isolated mycelial growth of Tobacco Star Disease Fungi by the pH and enzyme dual-stimulation controlled-release nanopesticide prepared in Example 1 and the technical grade pesticide of Comparative Example 1. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the embodiments.

[0031] Example 1

[0032] The pH- and enzyme-responsive controlled-release fluazinam nanopesticide of the present invention is prepared by the following steps:

[0033] (1) Preparation of drug-loaded zinc-based MOF materials

[0034] 1.36 mol of zinc acetate dihydrate and 13.64 mol of dimethylimidazole were dispersed in deionized water. After stirring for 5 minutes, an ethanol solution of fluazinam technical (0.32 mmol of fluazinam technical dissolved in 3.75 mL of ethanol) was added, and stirring was continued for 2 hours. Subsequently, the sample was centrifuged at 8000 rpm for 25 min and washed twice alternately with 20% ethanol solution and deionized water. After vacuum drying at 50 °C, zinc-based MOF material loaded with fluazinam technical (FZN@ZIF-8) was obtained.

[0035] (2) Preparation of surface pectin-modified nanopesticides

[0036] 3 mg of silane coupling agent KH550 was dispersed in 500 mL of deionized water and stirred for 10 minutes. Then, 3 g of FZN@ZIF-8 prepared in step (1) was added to the solution and stirred for 2 hours. Then, 1.5 g of pectin was added and stirred at 25 °C for 12 hours. After the reaction was completed, the sample was centrifuged at 8000 rpm for 25 minutes and washed once with 20% ethanol solution and deionized water alternately. After vacuum drying at 50 °C, the nano-pesticide FZN@ZIF-8@Pec was obtained.

[0037] Example 2

[0038] Based on Example 1, in step (1), the molar amount of fluazinam technical material was changed to 0.16 mmol, and the other conditions were the same as in Example 1.

[0039] Example 3

[0040] Based on Example 1, in step (2), the amount of pectin added was changed to 3g, and the pectin was added and stirred for 12h. The other conditions were the same as in Example 1.

[0041] Example 4

[0042] Based on Example 1, in step (1), the molar amount of fluazinam technical material added was changed to 0.16 mmol; in step (2), the amount of pectin added was changed to 3 g, pectin was added and stirred for 12 h, and the other conditions were the same as in Example 1.

[0043] Example 5

[0044] Based on Example 1, in step (2), the amount of silane coupling agent KH550 was changed to 1 mg, and the other conditions were the same as in Example 1.

[0045] Comparative Example 1

[0046] Fluazinam technical grade (FZN) is left untreated.

[0047] Comparative Example 2

[0048] Pectin (Pec) is not processed in any way.

[0049] Comparative Example 3

[0050] Based on Example 1, the zinc-based MOF material ZIF-8 was obtained without adding fluazinam technical.

[0051] Comparative Example 4

[0052] Based on Example 1, only the zinc-based MOF material FZN@ZIF-8 loaded with fluazinam technical obtained in step (1) was processed.

[0053] Structural characterization

[0054] The results of scanning electron microscopy, Fourier transform infrared spectroscopy, and thermal analysis were performed on Examples 1-4 and Comparative Examples 3-4. Figures 1-3 As shown.

[0055] Figure 1 This is a scanning electron microscope image. Figure 1 (a) ZIF-8 nanoparticles prepared in Comparative Example 3, whose average size was controlled to 200 nm, and which exhibited a typical cross-sectional cubic morphology due to the effect of the end-capping agent CTAB. Figure 1 (b) The FZN@ZIF-8 nanoparticles prepared in Comparative Example 4 showed a large number of granular protrusions on their surface, indicating successful loading of the active ingredient. Furthermore, the addition of the active ingredient during the synthesis process may have led to coordination competition, resulting in a reduction in the size of the nanoparticles to 150 nm. Figure 1 (c) is the nanoparticle FZN@ZIF-8@Pec after being coated with pectin in Example 1. The SEM image shows a rougher, scaly surface, which indicates that the pectin was successfully coated on the surface of the nanoparticles. Figure 1 (d) is an electron microscope image of Example 2, showing the relationship between FZN and Zn at low concentrations. 2+ The weak competitive coordination leads to more intense kinetics in the nucleation and growth processes, resulting in partial aggregation of ZIF-8 crystal particles during their formation. Figure 1 (e) is an electron microscope image taken after the amount of pectin was increased in Example 3. It can be observed that with the increase of pectin content, some adhesion occurs between the nanoparticles. Figure 1 (f) is an electron microscope image taken in Example 4. Loading with low concentration of FZN and encapsulating a large amount of pectin ultimately resulted in the nanoparticles exhibiting a state of random aggregation.

[0056] Figure 2 The Fourier transform infrared spectrum of ZIF-8 is shown at 2927 cm⁻¹. -1 For imidazole C–H stretching vibration, at 995 cm⁻¹ -1 The stretching vibration of the CN bond occurs at 421 cm⁻¹. -1 A strong spectral band was observed at 3322, 1631, 1444, and 875 cm⁻¹, corresponding to the Zn–N stretching vibration that occurs when zinc atoms connect with nitrogen atoms coordinated in 2-MIM during the formation of ZIF-8; the FZN technical grade showed bands at 3322, 1631, 1444, and 875 cm⁻¹, respectively. -1 Characteristic peaks were observed at 3388 cm⁻¹, corresponding to the stretching vibrations of NH and NO in aromatic compounds, the stretching vibration peak of CF in trifluoromethyl groups, and the stretching vibration peak of C-Cl; Pec showed a peak at 3388 cm⁻¹. -1 The pectin molecule exhibits numerous broad and strong absorption peaks for OH stretching vibrations, at 1743 and 1630 cm⁻¹. -1The sharp peaks at 1500-1750 cm⁻¹ represent the stretching vibration peak of esterified C=O and the carboxyl group of the pectin structure, respectively. Comparison revealed that FZN@ZIF-8 simultaneously possesses the standard characteristic peaks of both the original drug FZN and the carrier ZIF-8, indicating that the in-situ generated nanoparticles successfully loaded the original drug and exhibit a certain degree of structural stability. Furthermore, the peaks at 1500-1750 cm⁻¹... -1 The weakening of the range peaks indicates that pectin was successfully loaded onto the surface of the nano-pesticide.

[0057] Figure 3 The thermogravimetric analysis (TGA) curves show that the FZN@ZIF-8@Pec nanopesticide underwent three main stages of weight loss. The first stage (25–125℃) resulted in approximately 3% weight loss, possibly due to the removal of water from the sample and its surface. The second stage (125–340℃) saw 12.22% weight loss attributed to the carbonization of the FZN technical material and pectin on the carrier; the individual FZN and Pec materials also experienced rapid weight loss during this stage. The final stage involved the collapse of the ZIF-8 material structure, resulting in a weight loss of approximately 56.13%. Overall, the introduction of the ZIF-8 carrier significantly improved the thermal stability of the FZN technical material.

[0058] Performance testing

[0059] (1) pH / pectinase response performance test

[0060] The controlled-release performance of the FZN@ZIF-8@Pec nanopesticide formulation prepared in Example 1 was tested.

[0061] Test method: Under pH conditions of 5, 7, 9 and pH=7 with the addition of 1 mg / mL pectinase, 5 mL of SA-HNTs-EB nanopesticide was placed in a dialysis bag (8000-14000 Da) using 20% ​​ethanol solution as the dialysate to investigate the release rate of EB from SA-HNTs-EB nanopesticide over 0, 1, 2, 4…240 h. During this period, 4 mL of permeate was taken each time and tested on a UV spectrophotometer, and 4 mL of dialysate was added to the original solution. Finally, the cumulative release rate was calculated according to formula (1).

[0062]

[0063] In the formula, E r V represents the cumulative percentage of FZN released; e V0 represents the sample volume (4 ml) taken over a fixed time period; C represents the controlled-release solution volume; n The concentration of FZN in the controlled-release solution (mg / L) during time period n; M refers to the content of the active ingredient of FZN in the FZN@ZIF-8@Pec nano-pesticide (mg).

[0064] At room temperature, the release of FZN@ZIF-8@Pec nanopesticide formulations under different pH conditions and pectinase levels is as follows: Figure 4 As shown.

[0065] Depend on Figure 4 The release of nano-pesticides can be divided into two main stages: In the initial 48 hours, ZIF-8@FZN@Pec releases rapidly, with cumulative release rates of 29.36%, 16.24%, 20.15%, and 25.06% at pH 5, 7, and 9, respectively, and in environments with added pectinase. Subsequently, the release rate gradually plateaus, with final cumulative release rates reaching 59.15%, 35.09%, 37.31%, and 47.32%, respectively. In summary, the release rate of nano-pesticides is fastest under acidic conditions, mainly due to the rapid collapse of the ZIF-8 metal-organic framework under acidic conditions, leading to accelerated pesticide release. Furthermore, at pH 7, the release rate significantly increases after the addition of pectinase. This is because the surface modification of pectin forms the core-shell structure of the nano-pesticide, accelerating the release rate after the addition of pectinase.

[0066] (2) Leaf surface wetting performance test

[0067] The water contact angles of FZN@ZIF-8@Pec prepared in Example 1 and the technical grade FZN in Comparative Example 1 were tested.

[0068] Test Method: A dispersion of 1000 mg / L FZN and FZN@ZIF-8@Pec was prepared. Leaf contact angle was measured using an automated contact angle meter (SDA30S, Kruss, Germany) to study its adhesion to tobacco leaves. Fresh tobacco leaves were washed, dried, and fixed onto a glass slide. A 3 μL drop of the sample was placed on the tobacco leaf, and the change in contact angle was recorded over 8 minutes at 2-minute intervals. Test results are as follows: Figure 5 As shown.

[0069] pass Figure 5The water contact angle comparison chart shows that, within the measurement range of 0-8 minutes, the contact angles of the FZN@ZIF-8@Pec solution were 82.4°, 77.05°, 72.35°, 67°, and 60.75°, respectively, while the contact angles of the FZN solution were 77°, 73.3°, 64.9°, 58.65°, and 55.6°, respectively. The FZN@ZIF-8@Pec solution decreased from an initial 77° to 55.6°, while the FZN solution, as a comparison, only decreased from 82.4° to 60.75°, with a more significant difference appearing at 8 minutes. Clearly, the FZN@ZIF-8@Pec nanopesticide exhibits better wetting and spreading properties on the tobacco leaf surface. This further demonstrates that the large number of hydrophilic hydroxyl groups and the smaller particle size of the nanopesticide reduce the surface tension of its aqueous solution, enhancing its hydrophilicity, which will be more beneficial for plant absorption.

[0070] (3) Rainwater erosion resistance test

[0071] The water contact angles of FZN@ZIF-8@Pec prepared in Example 1 and the technical grade FZN in Comparative Example 1 were tested.

[0072] Test Method: Solutions of 1 mg / mL FZN and FZN@ZIF-8@Pec were prepared and mixed with equal volumes of 1 mg / mL Rhodamine B stain. After rinsing and drying the harvested tobacco leaves, the two sample solutions were evenly sprayed onto the leaves using a spray bottle. The leaves were then placed on glass slides and observed under an inverted fluorescence microscope. After 6 hours, 50 mL of deionized water was used to simulate rainwater washing, and the leaves were allowed to air dry naturally before being observed under an inverted fluorescence microscope. The test results are as follows: Figure 6 As shown.

[0073] Depend on Figure 6 As can be seen, tobacco pubescence stained with Rhodamine B is clearly visible on the tobacco leaves in bright field. Comparing the dark field images of FZN@ZIF-8@Pec (b, d, f) and fluazinam technical (h, j, i) prepared in Example 1, it is evident that with increasing rinsing cycles, the number of fluorescently labeled nanopesticide particles and fluazinam technical particles on the tobacco leaves gradually decreases. However, FZN@ZIF-8@Pec still exhibits a larger luminescent area than the FZN technical formulation. Clearly, the FZN@ZIF-8@Pec nanopesticide particles have higher adhesion to the tobacco leaf surface than the technical FZN, and possess better resistance to rain rinsing.

[0074] (4) Dispersion stability test

[0075] The dispersion water stability properties of the FZN@ZIF-8@Pec prepared in Example 1 and the materials prepared in Comparative Examples 1 to 4 were tested.

[0076] Test Method: The zeta potentials of 1 mg / L FZN@ZIF-8@Pec, FZN@ZIF-8, FZN, Pec, and ZIF-8 were measured using a zeta potential meter (NANO ZS90, Malvern, UK). The prepared solutions were diluted to 1 mg / L, sonicated for 20 minutes to ensure uniform dispersion, and then water was used as the solvent to measure the zeta potentials of the materials. The test results are as follows: Figure 7 As shown.

[0077] Depend on Figure 6 The zeta potentials were found to be -1.3 mV for Comparative Example 1, 10.3 mV for Comparative Example 3, 22.3 mV for Comparative Example 4, -52.4 mV for Comparative Example 2, and -19.4 mV for ZIF-8@FZN@Pec. Higher zeta potentials indicate better dispersion stability of the system. Comparison revealed that the ZIF-8@FZN nanoparticles loaded with the original drug exhibited better dispersion stability than the original drug.

[0078] (5) Sterilization performance test

[0079] The bactericidal effects of FZN@ZIF-8@Pec prepared in Example 1 and the original FZN in Comparative Example 1 at different concentrations were tested.

[0080] Test Method: Solid culture media containing different concentrations of FZN@ZIF-8@Pec and FZN were prepared. Using a 9mm diameter punch, holes were made at the edge of the *Aureobasidium aegerita* fungus to obtain mycelial discs. The mycelial side of the mycelial discs was placed in the prepared solid culture medium. After sealing the medium with sealing film, it was placed in a 28℃ constant temperature shaking incubator. Colony growth was observed on day 10. Test results are as follows: Figure 8 As shown in Table 1.

[0081] Table 1

[0082]

[0083] Depend on Figure 8 It can be seen that the colony diameter of *Aureobasidium aizoon* decreases with increasing concentration of nano-pesticide formulations. Comparison with FZN technical grade at the same concentration revealed that the Zn in the nano-pesticide carrier... 2+ It exhibited excellent synergistic effects with fluazinam technical grade. At day 10, FZN and FZN@ZIF-8@Pec showed significant synergistic effects against EC50 in tobacco auricularia auricula-judae. 50The concentrations were 42.837 mg / L and 33.462 mg / L, respectively. FZN@ZIF-8@Pec, with its lower EC50, exhibited stronger bactericidal effects. Although the bactericidal performance of the nano-pesticide was comparable to that of the FZN technical grade at high concentrations, its more efficient controlled release and lower FZN technical grade demonstrate that the synthesized nano-pesticide has greater potential for application.

Claims

1. A pH and enzyme dual stimuli-responsive controlled-release fluazaindane nano-pesticide, characterized in that, The nano-pesticide comprises a carrier, flupentixol raw material and pectin; the carrier is zinc-based metal organic framework material ZIF-8, flupentixol raw material is added in raw materials for preparing ZIF-8, and the flupentixol is in-situ loaded on ZIF-8; pectin is wrapped on the surface of ZIF-8 loaded with flupentixol raw material through a connecting agent, one end of the connecting agent is connected with ZIF-8, and the other end is connected with pectin. 2.The pH and enzyme dual-stimuli responsive controlled-release fluazaindane nano-pesticide according to claim 1, characterized in that, The molar ratio of zinc ions in the raw materials of ZIF-8 to flupentixol raw material is 8500:(1-2). 3.The pH and enzyme dual-stimuli responsive controlled-release fluazaindane nano-pesticide according to claim 1, wherein, The mass ratio of ZIF-8 loaded with flupentixol raw material to pectin is 2:(1-2). 4.The pH and enzyme dual-stimuli responsive controlled-release fluazaindane nano-pesticide of claim 1, wherein, The connecting agent is silane coupling agent, one end of the silane coupling agent is connected with metal sites on the surface of ZIF-8 through coordination reaction, and the other end is connected with carboxyl groups of pectin through amide condensation reaction.

5. A preparation method of the pH and enzyme dual-stimulus response controlled-release fluazaindane nano-pesticide according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: (1) adding ligands of zinc-based metal organic framework material ZIF-8, zinc salt, capping agent and flupentixol raw material into a solvent, and synthesizing ZIF-8 loaded with flupentixol raw material through one-pot method; (2) adding a connecting agent into the solvent, then adding ZIF-8 loaded with flupentixol raw material prepared in step (1), so that the connecting agent is first connected with ZIF-8, then adding pectin, so that the connecting agent is connected with pectin, thereby wrapping pectin on the surface of ZIF-8 loaded with flupentixol raw material.

6. The preparation method of the pH and enzyme dual-stimuli responsive controlled-release fluazaindane nano-pesticide according to claim 5, characterized in that, In step (2), the connecting agent is silane coupling agent, the connecting reaction temperature of the silane coupling agent with ZIF-8 or pectin is 20-30℃, and the reaction time is 12-24 hours.

7. The preparation method of the pH and enzyme dual-stimulus response controlled-release flupentixol nano-pesticide according to claim 5, wherein the silane coupling agent is γ-aminopropyl triethoxysilane, and the mass ratio of the silane coupling agent to zinc-based metal organic framework material loaded with flupentixol raw material is (1-3):3000.

8. The preparation method of the pH and enzyme dual-stimuli responsive controlled release fluazaindane nano-pesticide according to claim 5, characterized in that, In step (1), the ligand of ZIF-8 is dimethyl imidazole. 9.The preparation method of the pH and enzyme dual-stimuli responsive controlled-release fluazaindane nano-pesticide of claim 5, characterized in that, In step (1), the capping agent is hexadecyl trimethyl ammonium bromide.

10. Application of the pH and enzyme dual-stimulus response controlled-release flupentixol nano-pesticide according to any one of claims 1-4 in preventing and treating tobacco brown spot.

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