A pharmaceutical composition for controlling soil-borne diseases of rice and a preparation method thereof

Abstract

This invention belongs to the field of pesticide technology, and more specifically relates to a pesticide composition for controlling soil-borne diseases of rice and its preparation method. The pesticide composition of this invention exhibits excellent control effects against rice bakanae disease, damping-off, and sheath blight, with a long-lasting effect, meeting the control needs throughout the entire rice growth cycle. Simultaneously, the introduction of an ecological regulator adjusts the soil pH to a suitable range, promoting the reproduction of beneficial microorganisms, which not only reduces the amount of chemical pesticides used but also significantly increases rice yield and reduces the risk of pesticide residues.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, and more specifically relates to a pesticide composition for controlling soil-borne diseases of rice and its preparation method. Background Technology

[0002] Soil-borne diseases of rice (such as bakanae disease, damping-off, and sheath blight) are among the main factors restricting high and stable rice yields, seriously threatening rice production safety. Currently, the control of soil-borne rice diseases mainly relies on chemical agents. Existing technologies typically employ single chemical agents (such as carbendazim and pyraclostrobin) or traditional compound formulations. However, the inventors have discovered that existing technical solutions have many shortcomings in practical application: First, there is a high risk of drug resistance. Long-term, single-use of specific chemical agents can lead to significant drug resistance in pathogens, resulting in a gradual decline in control effectiveness, necessitating increased dosages, and further exacerbating the environmental burden.

[0003] Secondly, the effect is short-lived. After conventional pesticides are applied to the soil, they are easily degraded or washed away due to the influence of soil microorganisms and the physicochemical environment. They cannot continuously inhibit the infection of pathogens throughout the entire growth period of rice, requiring multiple applications and increasing labor costs.

[0004] Secondly, they have poor environmental compatibility. Some chemical agents can damage the beneficial microbial communities in the soil. Long-term use can disrupt the soil's microecological balance and poses a risk of pesticide residue exceeding standards, affecting rice quality and food safety.

[0005] Finally, there is a lack of synergistic effects. Most existing compound formulations are simple mixtures, and the components often fail to produce synergistic effects or may even antagonize each other. This necessitates increasing the dosage to achieve the desired control effect, which not only increases costs but also fails to solve the aforementioned drug resistance and environmental problems.

[0006] Therefore, there is an urgent need to develop a pharmaceutical composition that is highly efficient, long-lasting, environmentally friendly, and whose components can produce synergistic effects. Summary of the Invention

[0007] To address the technical problems of high pesticide resistance, short duration of action, poor environmental compatibility, and lack of synergistic effects among components in existing technologies, this invention provides a pesticide composition for the prevention and control of soil-borne diseases of rice and its preparation method. Through the specific ratio and synergistic effect of active components, slow-release carriers, ecological regulators, and stabilizing synergists, this invention achieves efficient and long-lasting control of soil-borne diseases of rice and improves the soil microenvironment.

[0008] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention: provides a pesticide composition for controlling soil-borne diseases of rice, comprising, by weight percentage: 30-50 parts of active ingredient, 20-40 parts of sustained-release carrier, 10-20 parts of ecological regulator and 5-15 parts of stabilizing synergist; The active components include azoxystrobin, carbendazim, and thifluzamide; The sustained-release carrier comprises polylactic acid-glycolic acid copolymer and bentonite; The ecological regulators include sodium humate and alginate; The stabilizing synergist includes polyvinyl alcohol and a silane coupling agent.

[0009] Furthermore, the mass ratio of azoxystrobin, carbendazim, and thifluzamide is 1-3:1-2:0.5-1.5.

[0010] The ternary compound of azoxystrobin, carbendazim, and thifluzamide has three active components with different mechanisms of action: azoxystrobin is a mitochondrial respiration inhibitor, carbendazim is a microtubule protein inhibitor, and thifluzamide is a succinate dehydrogenase inhibitor. The synergistic effect of the three significantly broadens the fungicidal spectrum and has excellent control efficacy against soil-borne diseases such as rice sheath blight, bakanae disease, and damping-off. At the same time, the ternary compound effectively delays the development of drug resistance in pathogens and significantly improves the control efficacy.

[0011] Furthermore, the mass ratio of the polylactic acid-glycolic acid copolymer to bentonite is 1-3:0.5-1.5.

[0012] Furthermore, the mass ratio of sodium humate to alginic acid is 2-4:0.5-1.5.

[0013] Sodium humate regulates soil pH and promotes the formation of soil aggregates; alginic acid, as a biostimulant, is rich in natural plant hormones and trace elements, which can promote rice root development and enhance the plant's disease resistance; the two work together to provide favorable conditions for the reproduction of beneficial microorganisms, inhibit the growth of pathogens, and produce a dual synergistic effect of "chemical + biological" with the active components, thus significantly improving the prevention and control effect.

[0014] Furthermore, the mass ratio of the polyvinyl alcohol to the silane coupling agent is 3-5:0.5-1.

[0015] Polyvinyl alcohol improves the film-forming properties of the sustained-release carrier, while silane coupling agents enhance the interfacial bonding between the active ingredient and the sustained-release carrier, thereby improving the uniformity of pesticide particle dispersion in the soil and increasing particle strength, ensuring stable efficacy and long-lasting sustained-release performance.

[0016] The second technical solution of the present invention provides a method for preparing the above-mentioned agent composition for controlling soil-borne diseases of rice, comprising the following steps: Polylactic acid-glycolic acid copolymer was dissolved in ethyl acetate to obtain an organic phase solution; bentonite was dispersed in water, stirred and swollen to prepare an inorganic phase suspension; The active component is added to an organic phase solution and stirred for encapsulation to obtain microspheres of the active component encapsulated on an organic carrier. The active component microspheres were added to the inorganic phase suspension and stirred for adsorption treatment (bentonite was adsorbed on the surface of the microspheres to form a dual sustained-release structure), thus obtaining microspheres with a dual sustained-release structure. The ecological regulator is dissolved in water to prepare a solution with a concentration of 10-15 wt%. The solution is mixed with the microspheres with the dual slow-release structure at 20-30℃ and stirred for 30-45 minutes. Then, polyvinyl alcohol and silane coupling agent are added, stirred evenly, extruded and granulated, and then dried in a gradient to obtain the agent composition for the prevention and control of soil-borne diseases of rice.

[0017] Furthermore, the concentration of the organic phase solution is 8-12 wt%.

[0018] Furthermore, the stirring and swelling temperature is 50-60℃, and the time is 2-3 hours.

[0019] Furthermore, the concentration of the inorganic phase suspension is 15-20 wt%.

[0020] Furthermore, the stirring and embedding treatment is carried out at a speed of 800-1000 rpm, a temperature of 35-40℃, and a time of 1-2 hours.

[0021] Furthermore, the stirring adsorption treatment is carried out at a speed of 600-800 rpm, a temperature of 30-35℃, and a time of 2-3 hours.

[0022] Furthermore, the polyvinyl alcohol is added in the form of an aqueous solution at a concentration of 5-8 wt%.

[0023] Furthermore, the extrusion temperature of the extrusion granulation is 35-40℃, and the particle size is 2-4mm.

[0024] Furthermore, the gradient drying process involves first drying at 35-40℃ for 2-3 hours, and then raising the temperature to 50-60℃ to dry until the moisture content is ≤5%.

[0025] The preparation method of this invention achieves synergistic effects between the active component and the sustained-release carrier through a stepwise encapsulation process: the organic carrier (polylactic acid-glycolic acid copolymer) forms a primary encapsulation layer, which enables the slow release of the active component through biodegradation; the inorganic carrier (modified bentonite) forms a secondary encapsulation layer, which further delays the release rate through interlayer adsorption. The synergy between the two significantly extends the duration of effect; the gradient drying process avoids the degradation of heat-sensitive active components; and the stabilizing synergist enhances the interfacial bonding force during the encapsulation process, thereby improving the particle strength and ensuring the durability of the sustained-release performance.

[0026] The present invention discloses the following technical effects: The pharmaceutical composition of this invention exhibits excellent control effects against rice bakanae disease, damping-off, and sheath blight, with a long-lasting effect, meeting the control needs throughout the entire rice growth cycle. Simultaneously, the introduction of ecological regulators adjusts the soil pH to a suitable range, promoting the reproduction of beneficial microorganisms. This not only reduces the amount of chemical agents used but also significantly increases rice yield and lowers the risk of pesticide residues.

[0027] The pharmaceutical composition of this invention exhibits synergistic effects among its various raw material components. Specifically, the sustained-release carrier forms a microcapsule structure during preparation, effectively encapsulating the active ingredient, thus reducing the release rate and significantly extending the duration of effect, solving the problem of easy loss of conventional pharmaceuticals. The ecological regulator modifies the soil microecological environment, creating conditions unfavorable to pathogen survival and reducing pathogen spore germination rates. Alginic acid promotes rice root development and enhances plant disease resistance, complementing the chemical bactericidal effect of the active ingredient, resulting in a dual synergistic effect of "chemical + biological," thus improving control efficacy. The stabilizing synergist significantly improves the film-forming properties and particle strength of the sustained-release carrier, while the silane coupling agent enhances the interfacial bonding between the active ingredient and the carrier, significantly improving the uniformity of particle dispersion in the soil and increasing particle strength, ensuring uniform distribution and stable release of the active ingredient in the soil.

[0028] In the preparation method of this invention, a stepwise encapsulation process is employed: primary encapsulation with an organic carrier forms a microsphere structure, while secondary encapsulation with an inorganic carrier forms an adsorption layer. This dual sustained-release structure significantly reduces the drug release rate and prolongs the duration of effect, solving the problem of easy drug loss in conventional methods. The carrier pretreatment process involves the polylactic acid-glycolic acid copolymer swelling to form a porous structure, improving the encapsulation rate of the active components. The modified bentonite, after swelling, increases the interlayer spacing, enhancing adsorption capacity. The synergistic effect of these two processes improves encapsulation efficiency. A low-temperature composite process is used: the ecological regulator is added at low temperatures, avoiding the degradation of bioactive substances in alginate and retaining over 95% of the bioactivity, ensuring the synergistic effect of the "chemical + biological" dual enhancement. This process also provides stable synergistic effects. Agent enhancement process: Polyvinyl alcohol and silane coupling agent form a cross-linked network during encapsulation, enhancing the interfacial bonding force between the active component and the carrier, improving particle strength and dispersion uniformity, and ensuring stable release of the agent in the soil; Gradient drying process: Gradient drying at low temperature (35-40℃) followed by medium temperature (50-60℃) avoids degradation of heat-sensitive active components, while reducing surface cracks in the particles, maintaining particle integrity, and further improving sustained-release performance and product stability; Extrusion granulation process: Extrusion granulation at 35-40℃ allows the sustained-release carrier and active component to form a dense particle structure, extending the disintegration time of the agent particles and significantly improving sustained-release performance. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0035] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.

[0036] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0037] The silane coupling agent used in the specific embodiments of the present invention is KH550.

[0038] Example 1 The preparation steps of the pesticide composition for controlling soil-borne diseases of rice include: S1. Prepare the following raw materials according to the following proportions by weight: 40 parts of active ingredient, 30 parts of sustained-release carrier, 15 parts of ecological regulator and 10 parts of stabilizing synergist; The active ingredients are azoxystrobin, carbendazim and thifluzamide in a mass ratio of 2:1.5:1; The sustained-release carrier is a polylactic acid-glycolic acid copolymer and bentonite in a mass ratio of 2:1; The ecological regulator is sodium humate and alginate in a mass ratio of 3:1; The stabilizing synergist is a polyvinyl alcohol and silane coupling agent in a mass ratio of 4:1.

[0039] S2. Pretreatment of the sustained-release carrier: Polylactic acid-glycolic acid copolymer was dissolved in ethyl acetate to prepare an organic phase solution with a concentration of 10%; modified bentonite was dispersed in deionized water and stirred and swollen at 55°C for 3 hours to prepare an inorganic phase suspension with a concentration of 20%.

[0040] S3. Primary embedding of active components: The active components are added to the organic phase solution and stirred at 40°C and 1000 rpm for 2 hours to form microspheres of active components embedded in the organic carrier. S4. Secondary encapsulation of inorganic carrier: The active component microspheres encapsulated by the organic carrier obtained in step S3 are slowly added to the inorganic phase suspension and stirred at 35°C and 800 rpm for 3 hours to allow bentonite to be adsorbed on the surface of the microspheres and form a dual slow-release structure. S5, Ecological regulator compound: Dissolve the ecological regulator in deionized water to prepare a 15% solution, and slowly add it to the product obtained in step S4 at 30°C, and continue stirring for 45 minutes; S6. Stabilizing and enhancing agent: Polyvinyl alcohol is dissolved in deionized water to prepare a 5% solution. Silane coupling agent is added, and after mixing evenly, it is added to the product obtained in step S5. The mixture is stirred at 35°C for 1 hour to enhance the interfacial bonding force between the carrier and the active component. S7. Extrusion granulation: The product obtained in step S6 is granulated by an extrusion granulator, with the particle size controlled between 2-4 mm and the extrusion temperature controlled between 35-40℃. S8. Gradient drying: The granulated particles are first dried at 35°C for 3 hours, and then the temperature is raised to 50°C to dry until the moisture content is ≤5%, thus obtaining the pharmaceutical composition.

[0041] Example 2 The preparation steps of the pesticide composition for controlling soil-borne diseases of rice include: S1. Prepare the following raw materials according to the following proportions by weight: 30 parts of active ingredient, 20 parts of sustained-release carrier, 10 parts of ecological regulator and 5 parts of stabilizing synergist; The active ingredients are azoxystrobin, carbendazim and thifluzamide in a mass ratio of 1:1:0.5; The sustained-release carrier is a polylactic acid-glycolic acid copolymer and bentonite in a mass ratio of 1:1.5; The ecological regulator is sodium humate and alginate in a mass ratio of 2:1.5; The stabilizing synergist is a polyvinyl alcohol and silane coupling agent in a mass ratio of 3:0.5.

[0042] S2-S8, same as in Example 1.

[0043] Example 3 The preparation steps of the pesticide composition for controlling soil-borne diseases of rice include: S1. Prepare the following raw materials according to the following proportions by weight: 50 parts of active ingredient, 40 parts of sustained-release carrier, 20 parts of ecological regulator and 15 parts of stabilizing synergist; The active ingredients are azoxystrobin, carbendazim and thifluzamide in a mass ratio of 3:2:1.5; The sustained-release carrier is a polylactic acid-glycolic acid copolymer and bentonite in a mass ratio of 3:0.5; The ecological regulator is sodium humate and alginate in a mass ratio of 24:0.5; The stabilizing synergist is a polyvinyl alcohol and silane coupling agent in a mass ratio of 5:0.5.

[0044] S2-S8, same as in Example 1.

[0045] Comparative Example 1 The difference compared to Example 1 is that the raw material does not contain ecological regulators; that is, the raw material consists only of active components, sustained-release carriers, and stabilizing synergists.

[0046] Comparative Example 2 The difference compared to Example 1 is that the raw material does not contain a stabilizing synergist; that is, the raw material consists only of the active component, the sustained-release carrier, and the ecological regulator.

[0047] Comparative Example 3 The preparation steps of the pharmaceutical composition include: S1. Prepare the following raw materials according to the following proportions by weight: 40 parts of active ingredient, 30 parts of sustained-release carrier, 15 parts of ecological regulator and 10 parts of stabilizing synergist; The active ingredients are azoxystrobin, carbendazim and thifluzamide in a mass ratio of 2:1.5:1; The sustained-release carrier is a polylactic acid-glycolic acid copolymer and bentonite in a mass ratio of 2:1; The ecological regulator is sodium humate and alginate in a mass ratio of 3:1; The stabilizing synergist is a polyvinyl alcohol and silane coupling agent in a mass ratio of 4:1.

[0048] S2. Mix the active ingredients, slow-release carrier, ecological regulator and stabilizing synergist evenly, adjust the moisture content to 20%, and granulate by extrusion granulator, with the particle size controlled between 2-4mm and the extrusion temperature controlled between 35-40℃. S3. Gradient drying: The granulated particles are first dried at 35°C for 3 hours, and then the temperature is raised to 50°C to dry until the moisture content is ≤5%, thus obtaining the pharmaceutical composition.

[0049] Comparative Example 4 The difference from Example 1 is that the sustained-release carrier is a polylactic acid-glycolic acid copolymer, meaning that the sustained-release carrier does not contain bentonite.

[0050] Comparative Example 5 Compared with Example 1, the difference is that the drying process in step S8 is: after granulation, drying at 80°C until the moisture content is ≤5%.

[0051] Comparative Example 6 The difference from Example 1 is that the polylactic acid-glycolic acid copolymer in the sustained-release carrier is replaced with an equal mass of polylactic acid.

[0052] Comparative Example 7 The difference from Example 1 is that sodium humate and alginate in the ecological regulator are replaced with an equal mass of fulvic acid.

[0053] Test case Field trials were conducted on the pharmaceutical compositions prepared in the examples and comparative examples: Experimental sites: Select fields with flat terrain, uniform fertility, and a history of severe occurrence of soil-borne diseases (especially sheath blight and damping-off).

[0054] Experimental variety: Yongyou 1538.

[0055] Plot setup: A randomized block design was adopted with 11 treatments (example + comparative example + blank control group CK). Each treatment was replicated 4 times. Each plot was 30 square meters in size. There were 0.5-meter guard rows between plots and guard rows around the plots. The same conventional field management measures were adopted.

[0056] Application method: Apply the pesticide to the soil after the rice transplanters have recovered from transplanting. The application rate is calculated to be 300 grams of active ingredient per hectare. Apply the pesticide evenly to each plot using the toxic soil method, and maintain a water layer of 3-5 cm.

[0057] 1. Prevention and control efficacy (disease index and prevention efficacy): Survey period: Late tillering stage of rice, booting stage (sheath blight), maturity stage (bakanae disease, damping-off disease).

[0058] Survey Methodology: Sheath blight: Refer to the "Guidelines for Field Efficacy Trials of Pesticides" (GB / T 17980.19), randomly sample 5 points in each plot, investigate 10 consecutive clumps at each point, record the total number of plants and the number of diseased plants, and calculate the disease index and control effect according to the 0-5 grade standard.

[0059] Bakanae disease: At maturity, survey the entire plot, record the number of diseased plants (elongated, dead), and calculate the incidence rate and control effect.

[0060] Damping-off disease: Investigate at the end of tillering stage and record the number of dead plants.

[0061] The formulas for calculating the disease index and prevention and control effectiveness are as follows: ; .

[0062] Table 1 As shown in Table 1, Example 1 performed best in controlling all three diseases. Although Examples 2 and 3 had different formulation ratios, thanks to the complete "dual slow-release + ecological regulation + stabilizing and enhancing" system, the efficacy remained above 79%, significantly better than all comparative examples. Comparative Example 6, which replaced PLGA with PLA (polylactic acid), showed a significant decrease in efficacy (the efficacy against rice sheath blight dropped to 64.7%). This indicates that the degradation rate of PLGA is more suitable for the disease control window of the rice growth cycle, while PLA's slow degradation or mismatched release mechanism prevented the active ingredient from reaching the optimal concentration during the disease outbreak period. Comparative Example 3 showed the worst results, proving that simple mixing cannot achieve targeted release; the data from Comparative Examples 1 and 2 show that the lack of ecological regulators or stabilizers weakens the permeability and stability of the pesticide in the soil, thereby reducing efficacy.

[0063] 2. Duration of effectiveness (dynamics of residual effective components in the soil): Sampling time: Day 1 after application (as initial value), 7 days, 15 days, 30 days, 45 days, and 60 days after application.

[0064] Sampling method: Multiple samples were taken from each plot (0-15cm topsoil layer), mixed thoroughly, and then the samples were quartered.

[0065] The total residues of azoxystrobin, carbendazim, and thifluzamide in the soil were determined.

[0066] Table 2 Table 2 shows that Comparative Example 3 had a concentration as high as 14.5 mg / kg on day 1, far exceeding the theoretical value, exhibiting a burst release effect. This could easily cause initial phytotoxicity and lead to insufficient efficacy in the later stages. Comparative Examples 5 and 4 also had high concentrations on day 1 (>11 mg / kg), indicating that high temperature destroyed the encapsulation structure and that bentonite played an important role in adsorbing the initial drug and inhibiting burst release. Example 1 had a moderate initial concentration (10.2 mg / kg), indicating that the sustained-release structure effectively controlled the initial release rate of the drug. Comparative Example 6 had the lowest concentration on day 1 (8.5 mg / kg) and decreased rapidly from day 45 to 60. This verifies that PLA, as a single carrier, has an inhibited initial release, which may lead to poor control of damping-off disease in the seedling stage and insufficient release momentum in the later stages. Example 1 maintained a high concentration of 6.2 mg / kg at day 60, proving that the dual sustained-release system of PLGA and bentonite can accurately match the needs of rice throughout its entire growth period.

[0067] 3. Rice yield and quality: Yield determination: The actual yield was measured at maturity, and the actual yield of each plot was recorded and converted into yield per mu (kg / mu).

[0068] Pesticide residues: The residues of pyraclostrobin, carbendazim, thifluzamide and their metabolites in rice were determined after harvest, and the determination was made in accordance with the "National Food Safety Standard Maximum Residue Limits for Pesticides in Food" (GB 23200 series).

[0069] Table 3 In Table 3, the yields of Examples 1-3 were significantly higher than those of the comparative examples, with Example 1 showing the highest yield increase (30.9%). This was attributed to its effective disease control throughout the entire growth period and favorable soil conditions. Comparative Example 3 had the highest residue level (0.15 mg / kg), likely due to initial burst release resulting in a large amount of drug not being adsorbed by the soil and instead volatilizing or being ineffectively absorbed by the crop. Although Comparative Example 6 had a slower release, its residue level (0.07 mg / kg) was still higher than that of Example 1, indicating that the synergistic encapsulation of PLGA and bentonite was more effective than PLA alone in limiting drug migration to grains. Therefore, Example 1 achieved a balance between high yield and low residue, demonstrating the significant potential of this formulation and process in ensuring food security.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pesticide composition for controlling soil-borne diseases of rice, characterized in that, By weight percentage, the raw materials include: 30-50 parts of active ingredient, 20-40 parts of sustained-release carrier, 10-20 parts of ecological regulator and 5-15 parts of stabilizing synergist; The active components include azoxystrobin, carbendazim, and thifluzamide; The sustained-release carrier comprises polylactic acid-glycolic acid copolymer and bentonite; The ecological regulators include sodium humate and alginate; The stabilizing synergist includes polyvinyl alcohol and a silane coupling agent.

2. The pharmaceutical composition according to claim 1, characterized in that, The mass ratio of azoxystrobin, carbendazim, and thifluzamide is 1-3:1-2:0.5-1.

5.

3. The pharmaceutical composition according to claim 1, characterized in that, The mass ratio of the polylactic acid-glycolic acid copolymer to bentonite is 1-3:0.5-1.

5.

4. The pharmaceutical composition according to claim 1, characterized in that, The mass ratio of sodium humate to alginic acid is 2-4:0.5-1.

5.

5. The pharmaceutical composition according to claim 1, characterized in that, The mass ratio of polyvinyl alcohol to silane coupling agent is 3-5:0.5-1.

6. A method for preparing a pesticide composition for controlling soil-borne diseases of rice according to any one of claims 1-5, comprising the steps of: The polylactic acid-glycolic acid copolymer was dissolved in ethyl acetate to obtain an organic phase solution; Bentonite was dispersed in water, stirred and swollen, and prepared into an inorganic phase suspension. The active component is added to an organic phase solution and stirred for encapsulation to obtain microspheres of the active component encapsulated on an organic carrier. The active component microspheres were added to the inorganic phase suspension and subjected to adsorption treatment by stirring to obtain microspheres with a dual sustained-release structure. The ecological regulator is dissolved in water to prepare a solution with a concentration of 10-15 wt%. The solution is mixed with the microspheres with the dual slow-release structure at 20-30℃ and stirred for 30-45 minutes. Then, polyvinyl alcohol and silane coupling agent are added, stirred evenly, extruded and granulated, and then dried in a gradient to obtain the agent composition for the prevention and control of soil-borne diseases of rice.

7. The preparation method according to claim 6, characterized in that, The concentration of the organic phase solution is 8-12 wt%; And / or, the stirring and swelling temperature is 50-60℃, and the time is 2-3h; And / or, the concentration of the inorganic phase suspension is 15-20 wt%.

8. The preparation method according to claim 6, characterized in that, The stirring and embedding treatment is carried out at a speed of 800-1000 rpm, a temperature of 35-40℃, and a time of 1-2 hours. And / or, the stirring adsorption treatment is performed at a speed of 600-800 rpm, a temperature of 30-35℃, and a time of 2-3 hours.

9. The preparation method according to claim 6, characterized in that, The polyvinyl alcohol is added in the form of an aqueous solution at a concentration of 5-8 wt%.

10. The preparation method according to claim 6, characterized in that, The extrusion temperature of the extrusion granulation is 35-40℃, and the particle size is 2-4mm; And / or, the gradient drying is as follows: first drying at 35-40℃ for 2-3 hours, then raising the temperature to 50-60℃ and drying until the moisture content is ≤5%.

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