Antibacterial environment-friendly rice pesticide and preparation method thereof

Abstract

The invention provides an antibacterial environment-friendly rice pesticide and a preparation method thereof, and relates to the technical field of rice pesticides, the pesticide is composed of the following components by weight: 5%-15% of a natural plant extract, 2%-8% of a microbial antibacterial component, 10%-20% of a biodegradable auxiliary material, 20%-40% of an environment-friendly solvent, and 30%-50% of water. By using natural plant extracts, an effective disease inhibition effect is provided, and harmful chemical residues in traditional chemical pesticides are avoided at the same time. The natural plant extract can be used for preventing and treating diseases and insect pests, and has low toxicity to the environment and crops, so that the protection of the ecological environment is facilitated. In addition, due to multiple selections of the natural plant extract, the pesticide can be customized according to different diseases, and wide applicability is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of rice pesticides, and in particular to an antibacterial and environment-friendly rice pesticide and a preparation method thereof. Background Art

[0002] As an important food crop worldwide, rice is often threatened by a variety of pests and diseases during its cultivation, especially rice blast, sheath blight and rice planthoppers. These pests and diseases not only seriously affect rice production, but also threaten food security and farmers' livelihoods. In order to effectively control pests and diseases, traditional rice disease control methods mainly rely on chemical pesticides. Such pesticides usually kill pathogens through synthetic chemical components. Although they have achieved good prevention and control effects in the short term, their long-term use has brought a series of problems.

[0003] First, the long-term use of chemical pesticides has made rice diseases resistant to pesticides. The resistance of pathogens to pesticides has gradually increased, resulting in a decrease in the effectiveness of pesticides. In order to ensure the harvest, farmers have to increase the frequency of pesticide application, which not only increases production costs, but also leads to an increase in drug residues. Secondly, the toxic components in traditional chemical pesticides are difficult to degrade in the environment and remain in the soil and water for a long time, causing damage to the ecological environment, affecting crop growth, and having an adverse effect on surrounding aquatic plants and animals. Soil pollution may also lead to the accumulation of heavy metals and harmful substances in crops, thereby affecting the safety of the human food chain.

[0004] In addition, the volatile components of chemical pesticides pollute air quality and water resources, especially during the application process, they pose an invisible threat to farmers' health. Traditional organic solvents will cause damage to the atmosphere after evaporation, and even cause air and water pollution problems in some areas. Traditional methods are not environmentally friendly and safe enough in pest control, and can no longer meet the needs of modern agriculture for green and sustainable development. In general, although traditional methods are effective in the short term, their long-term use has brought negative impacts on the environment, crops and human health. More environmentally friendly and sustainable alternatives are urgently needed and need to be optimized and improved. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems raised in the above background technology.

[0006] The present invention adopts the following technical scheme: an antibacterial and environment-friendly rice pesticide and a preparation method thereof, wherein the pesticide is composed of the following components in weight percentage: 5%-15% of natural plant extract, 2%-8% of microbial antibacterial component, 10%-20% of biodegradable auxiliary material, 20%-40% of environment-friendly solvent and 30%-50% of water.

[0007] Preferably, the natural plant extract is selected from at least one of the following: garlic extract, capsaicin, matrine, honeysuckle extract, azadirachtin, houttuynia extract, berberine extract, perilla extract or forsythia extract. Here, by selecting a variety of natural plant extracts, targeted antibacterial effects can be provided for different types of diseases. The combined use of different plant extracts enhances the broad-spectrum antibacterial ability of pesticides, while reducing toxicity to crops and the environment, ensuring the safety and environmental friendliness of pesticides.

[0008] Preferably, the microbial antibacterial component is an antibacterial metabolite produced by fermentation of Bacillus subtilis, Bacillus colloids, Streptomyces, Actinomycetes or Bacillus cereus. Here, the microbial antibacterial component is produced by fermentation of microorganisms such as Bacillus subtilis and Bacillus colloids, and its antibacterial metabolites have a long-lasting antibacterial effect and can effectively inhibit the growth of pathogens. In addition, microbial metabolites are naturally harmless, not easy to induce drug resistance, suitable for long-term use, and reduce negative impacts on crops and the environment.

[0009] Preferably, the biodegradable excipients include chitosan, starch-based materials, polylactic acid, sodium alginate or carboxymethyl cellulose. Here, biodegradable excipients such as chitosan and starch-based materials can be naturally degraded in the environment, avoiding the long-term residue of traditional chemical excipients and reducing the pollution to soil and water. At the same time, these excipients can form stable film-forming properties, increasing the persistence and durability of pesticides on the surface of crops.

[0010] Preferably, the environmentally friendly solvent is selected from ethanol, propylene glycol, ethylene glycol, isopropanol or ethyl acetate. Here, the use of environmentally friendly solvents such as ethanol, propylene glycol, etc. not only improves solubility, but also avoids the potential harm of traditional organic solvents to the environment and health. These solvents evaporate quickly and leave no residue, making pesticides more environmentally friendly and safe, which is in line with the trend of green agricultural development.

[0011] A method for preparing an environmentally friendly antibacterial rice pesticide comprises the following steps:

[0012] S1: Preparation of natural plant extracts: The active ingredients in natural plants are extracted by physical or chemical methods to prepare plant extracts; the extraction method can be water extraction, ethanol extraction, steam distillation or supercritical fluid extraction. The extracted plant extracts can be further concentrated by reduced pressure evaporation or freeze drying to improve the purity.

[0013] S2: Preparation of microbial antimicrobial ingredients: Microorganisms are fermented under suitable fermentation conditions to obtain antimicrobial metabolites; the fermentation process can be optimized according to the specific microbial species, using an aerated stirred tank fermentation system or a bioreactor to increase the yield and activity of antimicrobial metabolites.

[0014] S3: Preparation of biodegradable excipients: The biodegradable excipients are pretreated to prepare an excipient solution with good viscosity; during this process, the film-forming properties and adhesion of the solution can be improved by adjusting the temperature, stirring speed or adding a thickener.

[0015] S4: Preparation and mixing of environmentally friendly solvents: Environmentally friendly solvents, natural plant extracts, microbial antibacterial ingredients, and biodegradable excipients are mixed in specific proportions, and high-speed shear mixing or vacuum stirring is used to ensure uniform dispersion and prevent component separation to prepare a pesticide solution.

[0016] S5: Post-treatment and concentration adjustment of the solution: By adjusting the solution concentration, viscosity and pH value, ensure that the obtained pesticide solution has stable physical and chemical properties, and add antioxidants, stabilizers or emulsifiers to extend the shelf life and effectiveness of the product.

[0017] Preferably, in the extraction step of the natural plant extract, a supercritical carbon dioxide extraction method is used, the extraction pressure is 15-30MPa, the extraction temperature is 40-60°C, and the extraction time is 1-3 hours, which can maximize the retention of the active ingredients in the plant, or a dual solvent system extraction method is used to increase the extraction efficiency. Supercritical extraction is more environmentally friendly than traditional chemical extraction, can reduce organic solvent residues, and optimize the yield and quality of specific plant extracts by adjusting pressure and temperature. Here, the supercritical carbon dioxide extraction method can maximize the retention of active ingredients in plants, while avoiding the residual pollution of traditional solvent extraction, ensuring the high efficiency and environmental protection of pesticides. The use of a dual solvent system further improves the extraction efficiency, so that the quality and activity of plant extracts are guaranteed.

[0018] Preferably, the fermentation conditions of the microbial antibacterial component are: the pH value of the fermentation matrix is ​​controlled between 6.5-7.5, the fermentation temperature is controlled at 32±2°C, the stirring speed is 100-200rpm, the fermentation time is 36 hours, and the fermentation liquid is separated by a centrifugal separation device at a speed of 3000-5000rpm. To ensure the purity of the product, an automatic pH control system, continuous oxygen supply and nutrient solution supplementation technology can be used during the fermentation process to increase the yield and activity of antibacterial metabolites, and the final product is further concentrated and purified by freeze drying or membrane separation technology. Here, by precisely controlling the fermentation conditions, the yield and activity of the microbial antibacterial components can be greatly improved, ensuring the long-term antibacterial properties of the pesticide. At the same time, the antibacterial metabolites can be further concentrated and purified by freeze drying or membrane separation technology, making the final product more stable and efficient.

[0019] Preferably, when the chitosan is used as a biodegradable auxiliary material, the solvent in which it is dissolved is an acetic acid solution with a concentration of 1%-2%, the stirring time of the solution is 30-60 minutes, the viscosity is 100-300mPa·s, and the auxiliary material solution obtained has good film-forming properties and adhesion. By using ultrasound-assisted dissolution technology, the dissolution time of chitosan can be significantly reduced, the viscosity uniformity can be improved, and the chitosan is treated by nano-processing to enhance its film-forming properties and antibacterial properties, and a plasticizer such as glycerol or sorbitol is added to the auxiliary material solution to improve flexibility and adhesion. Here, ultrasound-assisted technology is used to accelerate the dissolution process of chitosan, and nano-processing enhances the film-forming properties and antibacterial properties of chitosan. By adding plasticizers, the adhesion and flexibility of pesticides on the surface of crops are further improved, making them more durable and effective under natural conditions.

[0020] Preferably, the final pesticide product is post-processed by spray drying, the inlet temperature of spray drying is 150-180°C, the outlet temperature is 60-80°C, the atomization pressure is 0.3-0.5MPa, and the obtained pesticide product is in the form of an easily soluble powder, which is convenient for storage and transportation; during the spray drying process, the drying temperature and pressure can be adjusted according to the volatility of different plant extracts and antibacterial ingredients to maximize the retention of active ingredients. Anti-caking agents such as silicon dioxide or microcrystalline cellulose can be added after drying to improve the fluidity and storage stability of the powder product. Here, spray drying technology can make pesticides into easily soluble powder products, which are convenient for storage and transportation, and maintain the stability of active ingredients. The addition of anti-caking agents effectively avoids the agglomeration of powder products during storage, enhances their fluidity and ease of use, and ensures the stability and effect of the product in practical applications.

[0021] Compared with the prior art, the advantages and positive effects of the present invention are:

[0022] 1. In the present invention, by using natural plant extracts, effective disease inhibition is provided while avoiding harmful chemical residues in traditional chemical pesticides. Such natural plant extracts can produce less toxicity to the environment and crops while preventing and controlling pests and diseases, thus being beneficial to the protection of the ecological environment. In addition, the multiple selectivities of natural plant extracts enable pesticides to be customized for different diseases and have a wide range of applicability.

[0023] 2. In the present invention, the antibacterial metabolites produced by fermentation provide a sustained antibacterial effect. This antibacterial mechanism is not easy to produce drug resistance, thereby effectively extending the service life of the pesticide and reducing the need for frequent application of pesticides to crops. Compared with chemical antibacterial agents, microbial antibacterial ingredients are more friendly to crops and the environment, and also improve the safety of pesticides.

[0024] 3. In the present invention, the use of biodegradable excipients and environmentally friendly solvents allows pesticides to be rapidly degraded after application and will not cause long-term pollution to the soil and water. This improvement not only reduces the negative impact on the environment, but also improves the safety and sustainability of the crop growth environment. The use of environmentally friendly solvents improves safety during production and use and reduces health risks for operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention provides an antibacterial and environment-friendly rice pesticide and a schematic diagram of the overall process structure of the preparation method thereof. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0028] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0029] Embodiment 1

[0030] The present invention provides a technical solution: an antibacterial and environment-friendly rice pesticide, the pesticide is composed of the following components in weight percentage: 10% garlic extract, 5% antibacterial metabolite, 15% chitosan, 35% environmentally friendly solvent, and 35% water;

[0031] First, fresh garlic was dried at 65°C for 6 hours and then crushed to a particle size of 0.5 mm. Garlic extract was obtained by steam distillation at 90°C for 3 hours. Secondly, Bacillus subtilis was fermented at pH 7.0 and 32°C for 36 hours, and then centrifuged at 4000rpm for 20 minutes to obtain antibacterial metabolites. Chitosan was dissolved in 1% acetic acid solution and stirred for 40 minutes to a high viscosity solution. Garlic extract, antibacterial metabolites and chitosan solution were mixed with an environmentally friendly solvent (such as ethanol) in proportion, mechanically stirred for 30 minutes, and finally water was added and stirred again to make an environmentally friendly pesticide solution. The pesticide has excellent antibacterial effect, while being environmentally friendly and pollution-free.

[0032] Embodiment 2

[0033] An antibacterial and environment-friendly rice pesticide, the pesticide is composed of the following components in percentage by weight: 8% capsaicin, 4% antibacterial metabolite, 12% starch-based material, 40% environmentally friendly solvent, and 36% water;

[0034] After the dried peppers were crushed into 0.3 mm particles, they were extracted with 70% ethanol at a solid-liquid ratio of 1:10 at 50°C for 3 hours, and the ethanol was removed by reduced pressure evaporation to obtain capsaicin. The mucilaginous Bacillus was fermented at pH 7.2 and 30°C for 36 hours, and the antibacterial metabolites were obtained by centrifugation at 3000rpm. The starch-based material was dissolved and stirred in water at 60°C for 45 minutes to prepare a solution. Finally, capsaicin, antibacterial metabolites, starch-based solution and environmentally friendly solvent were mixed and stirred for 20 minutes, and water was added to adjust the concentration to prepare an environmentally friendly pesticide solution. The pesticide has a significant inhibitory effect on rice blast and is environmentally safe.

[0035] Embodiment 3

[0036] An antibacterial and environment-friendly rice pesticide, the pesticide is composed of the following components in percentage by weight: 7% of matrine, 6% of antibacterial metabolites, 10% of polylactic acid, 37% of an environment-friendly solvent, and 40% of water;

[0037] Matrine was extracted from Sophora flavescens by supercritical carbon dioxide extraction (under conditions of 20MPa and 55°C) for 2 hours. Bacillus subtilis was inoculated into a fermentation matrix with a pH of 7.0, and after fermentation at 32°C for 36 hours, antibacterial metabolites were obtained by centrifugation at 5000rpm. After low-temperature drying at 50°C, polylactic acid was dissolved and stirred for 50 minutes to prepare a solution. Matrine, antibacterial metabolites and polylactic acid solution were mixed and stirred with an environmentally friendly solvent in proportion for 40 minutes, and water was added to adjust the concentration to prepare an environmentally friendly pesticide. The pesticide has a significant effect on the prevention and treatment of rice sheath blight, and each component is easily degradable, which meets the requirements of green agriculture.

[0038]

[0039]

[0040] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An antibacterial and environment-friendly rice pesticide, characterized in that: The pesticide is composed of the following components in percentage by weight: 5%-15% of natural plant extract, 2%-8% of microbial antibacterial component, 10%-20% of biodegradable auxiliary material, 20%-40% of environmentally friendly solvent and 30%-50% of water.

2. The antibacterial and environment-friendly rice pesticide according to claim 1, characterized in that: The natural plant extract is selected from at least one of the following: garlic extract, capsaicin, matrine, honeysuckle extract, azadirachtin, houttuynia cordata extract, berberine extract, perilla extract or forsythia suspensa extract.

3. The antibacterial and environment-friendly rice pesticide according to claim 1, characterized in that: The microbial antibacterial component is an antibacterial metabolite produced by fermentation of Bacillus subtilis, Bacillus mucilaginosus, Streptomyces, Actinomycetes or Bacillus cereus.

4. The antibacterial and environment-friendly rice pesticide according to claim 1, characterized in that: The biodegradable auxiliary material includes chitosan, starch-based material, polylactic acid, sodium alginate or carboxymethyl cellulose.

5. The antibacterial and environment-friendly rice pesticide according to claim 1, characterized in that: Features: The environmentally friendly solvent is selected from ethanol, propylene glycol, ethylene glycol, isopropanol or ethyl acetate.

6. A method for preparing the antibacterial and environment-friendly rice pesticide according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Preparation of natural plant extracts: The active ingredients in natural plants are extracted by physical or chemical methods to prepare plant extracts; the extraction method can be water extraction, ethanol extraction, steam distillation or supercritical fluid extraction. The extracted plant extracts can be further concentrated by reduced pressure evaporation or freeze drying to improve the purity. S2: Preparation of microbial antimicrobial ingredients: Microorganisms are fermented under suitable fermentation conditions to obtain antimicrobial metabolites; the fermentation process can be optimized according to the specific microbial species, using an aerated stirred tank fermentation system or a bioreactor to increase the yield and activity of antimicrobial metabolites. S3: Preparation of biodegradable excipients: The biodegradable excipients are pretreated to prepare an excipient solution with good viscosity; during this process, the film-forming properties and adhesion of the solution can be improved by adjusting the temperature, stirring speed or adding a thickener. S4: Preparation and mixing of environmentally friendly solvents: Environmentally friendly solvents, natural plant extracts, microbial antibacterial ingredients, and biodegradable excipients are mixed in specific proportions, and high-speed shear mixing or vacuum stirring is used to ensure uniform dispersion and prevent component separation to prepare a pesticide solution. S5: Post-treatment and concentration adjustment of the solution: By adjusting the solution concentration, viscosity and pH value, ensure that the obtained pesticide solution has stable physical and chemical properties, and add antioxidants, stabilizers or emulsifiers to extend the shelf life and effectiveness of the product.

7. The method for preparing the antibacterial and environment-friendly rice pesticide according to claim 5, characterized in that: In the extraction step of the natural plant extract, a supercritical carbon dioxide extraction method is used with an extraction pressure of 15-30 MPa, an extraction temperature of 40-60° C., and an extraction time of 1-3 hours, which can maximize the retention of effective ingredients in the plant, or a dual solvent system extraction method is used to improve the extraction efficiency. Supercritical extraction is more environmentally friendly than traditional chemical extraction, can reduce organic solvent residues, and optimize the yield and quality of specific plant extracts by adjusting pressure and temperature.

8. The method for preparing the antibacterial and environment-friendly rice pesticide according to claim 5, characterized in that: The fermentation conditions of the microbial antibacterial component are: the pH value of the fermentation matrix is ​​controlled between 6.5-7.5, the fermentation temperature is controlled at 32±2°C, the stirring speed is 100-200rpm, the fermentation time is 36 hours, and the fermentation liquid is separated by a centrifugal separation device at a speed of 3000-5000rpm. To ensure the purity of the product, an automatic pH control system, continuous oxygen supply and nutrient solution supplementation technology can be used during the fermentation process to increase the yield and activity of antibacterial metabolites, and the final product is further concentrated and purified by freeze drying or membrane separation technology.

9. The method for preparing the antibacterial and environment-friendly rice pesticide according to claim 5, characterized in that: When the chitosan is used as a biodegradable auxiliary material, the solvent in which it is dissolved is an acetic acid solution with a concentration of 1%-2%, the stirring time of the solution is 30-60 minutes, the viscosity is 100-300mPa·s, and the obtained auxiliary material solution has good film-forming property and adhesion. By using ultrasound-assisted dissolution technology, the dissolution time of chitosan can be significantly reduced, the viscosity uniformity can be improved, and the chitosan is treated by nano-processing to enhance its film-forming property and antibacterial property. At the same time, a plasticizer such as glycerol or sorbitol is added to the auxiliary material solution to improve flexibility and adhesion.

10. The method for preparing the antibacterial and environment-friendly rice pesticide according to claim 5, characterized in that: The final pesticide product is post-processed by spray drying, the inlet temperature of the spray drying is 150-180°C, the outlet temperature is 60-80°C, and the atomization pressure is 0.3-0.5MPa. The obtained pesticide product is in the form of easily soluble powder, which is convenient for storage and transportation; during the spray drying process, the drying temperature and pressure can be adjusted according to the volatility of different plant extracts and antibacterial ingredients to maximize the retention of active ingredients. Anti-caking agents such as silicon dioxide or microcrystalline cellulose can be added after drying to improve the fluidity and storage stability of the powder product.

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