Preparation method of camellia oleifera shell biopesticide

Abstract

The invention discloses a preparation method of a camellia oleifera shell biopesticide, and belongs to the technical field of biopesticides, and the preparation method comprises the following steps: S1, crushing camellia oleifera shells into camellia oleifera shell powder, and mixing the camellia oleifera shell powder with humic acid, lignosulfonate, a microbial agent and a filler to obtain mixed powder; s2, adding sodium alginate and a dispersing agent into deionized water to obtain a sodium alginate solution, and mixing the sodium alginate solution with the mixed powder to obtain dispersion liquid; s3, dissolving an emulsifier in vegetable oil to obtain an oil phase solution, dropwise adding the dispersion liquid into the oil phase solution, and emulsifying to obtain a mixed emulsion; s4, dissolving chitosan and a cross-linking agent in a dilute acid solvent to obtain a chitosan solution, and dispersing the chitosan solution in the mixed emulsion for cross-linking reaction; s5, after the reaction is completed, filtering to obtain the biopesticide, wherein the biopesticide is composed of a plurality of biopesticide capsules; the biopesticide disclosed by the invention has the effects of efficiently and lastingly inhibiting bacteria, killing insects, improving the soil environment and promoting the growth of crops.

Description

Technical Field

[0001] The invention relates to the technical field of biological pesticides, and in particular to a method for preparing a camellia oleifera shell biological pesticide. Background Art

[0002] Camellia oleifera shells are the residues produced during the processing of camellia oleifera. In the past, the treatment method was to use camellia oleifera shells as fuel for incineration. With the in-depth study of camellia oleifera shells, it was found that camellia oleifera shells are rich in bioactive ingredients, such as tea saponins, flavonoids, tea seed polysaccharides, etc. These ingredients have multiple biological activities, such as antibacterial, insecticidal, and plant growth regulating functions. The bioactive ingredients in camellia oleifera shells are usually extracted by extraction and other processes and then utilized, so that the camellia oleifera shells can be recycled in agricultural ecosystems and improve resource utilization. However, the utilization of bioactive ingredients in camellia oleifera shells faces challenges such as complex extraction processes, high costs, and poor stability of active ingredients, which restrict the efficient recycling of camellia oleifera shells in agricultural ecosystems.

[0003] A Chinese patent with announcement number CN114342963A discloses a method for controlling crop pests using camellia oleifera shells, comprising: removing impurities and drying the camellia oleifera shells after obtaining them, pretreating the dried camellia oleifera shells, extracting the pretreated camellia oleifera shells to obtain a camellia oleifera shell extract, preparing a crop pest control agent by mixing the obtained camellia oleifera shell extract with tripterygium wilfordii, dandelion, biological organic fertilizer, biological bacterial agent and amino oligosaccharide, and applying the prepared crop pest control agent to the soil after mixing with wood vinegar and water in proportion, and deep ploughing. The method of extracting the pretreated camellia oleifera shells to obtain a camellia oleifera shell extract comprises: obtaining pretreated camellia oleifera shell powder and adding 10 times the amount of water, stirring evenly, and then extracting using a microwave extractor to obtain a preliminary extract, adjusting the pH value of the preliminary extract, adding protease to the preliminary extract and heating it in a water bath, and filtering after natural cooling to obtain the camellia oleifera shell extract.

[0004] In the above patent, camellia oleifera shells are used for crop pest control, and pest control is achieved by extracting bioactive ingredients from the camellia oleifera shells. At the same time, the growth of crops is promoted by using tripterygium wilfordii bio-organic fertilizers and dandelion bio-organic fertilizers. However, the bioactive ingredients in the camellia oleifera shells are extracted using water, and the extraction efficiency of this extraction method is low, which may lead to problems such as low purity, poor quality and poor stability of the extracted bioactive ingredients. In addition, the camellia oleifera shells contain a large amount of plant fiber and elements necessary for crop growth such as nitrogen, phosphorus and potassium, and can be used as raw materials for bio-organic fertilizers. In fact, there is no need to use tripterygium wilfordii bio-organic fertilizers and dandelion bio-organic fertilizers. The above method uses a relatively complex and inefficient way to utilize the camellia oleifera shells, so there is still room for improvement. Summary of the invention

[0005] In view of the technical defects existing in the background technology, the present invention proposes a method for preparing a camellia oleifera shell biological pesticide, which solves the above technical problems and meets the actual needs. The specific technical scheme is as follows: A method for preparing a camellia oleifera shell biopesticide comprises the following steps: S1. Crush camellia oleifera shells to obtain camellia oleifera shell powder, and mix the camellia oleifera shell powder with humic acid, lignin sulfonate, microbial agent, and filler to obtain a mixed powder; S2, adding sodium alginate and a dispersant into deionized water, adjusting the pH, and then heating and stirring to dissolve to obtain a sodium alginate solution, and uniformly dispersing the mixed powder in the sodium alginate solution to obtain a dispersion; S3, dissolving the emulsifier in the vegetable oil to obtain an oil phase solution, uniformly dropping the dispersion into the oil phase solution and emulsifying to obtain a mixed emulsion; S4, dissolving chitosan and a cross-linking agent in a dilute acid solvent to obtain a chitosan solution, uniformly dispersing the chitosan solution in a mixed emulsion to obtain a cross-linked emulsion, and continuously stirring the cross-linked emulsion to allow sodium alginate and chitosan to undergo a cross-linking reaction to form a capsule wall material, wherein the capsule wall material wraps the mixed powder and together forms a biopesticide capsule; S5. After the sodium alginate and chitosan in the cross-linked emulsion have completed the reaction, the solution is filtered, and the solid product obtained by filtration is washed and dried to obtain a biopesticide, which is composed of a plurality of biopesticide capsules.

[0006] As a further technical solution of the present invention, the mixed powder includes the following components in percentage by mass: 50% to 70% of camellia oleifera shell powder, 10% to 20% of humic acid, 5% to 15% of lignin sulfonate, 5% to 15% of microbial agent, and 3% to 7% of filler; in step S1, the camellia oleifera shell is washed, dried, and then crushed to obtain the camellia oleifera shell powder.

[0007] As a further technical solution of the present invention, the microbial agent is selected from one or more of Trichoderma powder, white rot fungus powder, Bacillus powder, actinomycete powder, Paecilomyces lilacinus powder, Aschersporum powder, and Polychaeta tomophilus powder.

[0008] As a further technical solution of the present invention, the filler is selected from one or more of diatomaceous earth powder, bentonite powder, perlite powder, activated carbon powder, zeolite powder and kaolin powder.

[0009] As a further technical solution of the present invention, in step S2, sodium alginate and a dispersant are added to deionized water, the pH is adjusted to 5-6 by acetic acid, and then heated to 60-80° C. and stirred to dissolve to obtain a sodium alginate solution, wherein the mass percentage of sodium alginate in the sodium alginate solution is 1%.

[0010] As a further technical solution of the present invention, the mass ratio of the mixed powder, the sodium alginate solution and the dispersant in the dispersion is 1:(1-3):0.05; the dispersant is selected from one of carboxymethyl cellulose, xanthan gum and alkyl glycoside.

[0011] As a further technical solution of the present invention, the mixed emulsion includes the following components by mass percentage: 50% to 70% vegetable oil, 2% to 4% emulsifier, and 25% to 50% dispersion liquid; the vegetable oil is selected from one of soybean oil, corn oil, sunflower oil, and palm oil; the emulsifier is selected from one of lecithin, plant sterol esters, and sodium starch glycolate.

[0012] As a further technical solution of the present invention, in step S3, the mixed emulsion uses vegetable oil as the oil phase and as the continuous phase, and the dispersion forms droplets dispersed in the vegetable oil under the action of an emulsifier.

[0013] As a further technical solution of the present invention, in step S4, the dilute acid solution is selected from 1% by mass acetic acid solution, the mass percentage of chitosan in the chitosan solution is 5%, and the cross-linking agent is selected from one of genipin, inorganic calcium salt, and inorganic zinc salt.

[0014] As a further technical solution of the present invention, the mass ratio of chitosan, crosslinking agent and sodium alginate in the crosslinked emulsion is 1:(0.01-0.03):1.

[0015] The beneficial effects of the present invention are: The invention uses oil-tea camellia shell as the main raw material to prepare the biological pesticide, utilizes the biologically active components in the oil-tea camellia shell to inhibit bacteria and kill insects, and improves the antibacterial and insecticidal effects by compounding with humic acid, lignin sulfonate, and microbial agents, and has the functions of increasing the organic matter content of the soil, improving the soil structure, preventing soil compaction, promoting the growth of beneficial bacteria in the soil, and promoting the growth of crops. In addition, the mixed powder is wrapped in the capsule wall material with a cross-linked structure formed by chitosan and sodium alginate to prepare the biological pesticide capsule, so that after the biological pesticide capsule is applied to the soil, the effective components therein are gradually released in the soil through the slow-release mixed powder, thereby improving the utilization efficiency and durability of the biological pesticide. DETAILED DESCRIPTION

[0016] The implementation mode of the present invention is described below in conjunction with relevant embodiments. The implementation mode of the present invention is not limited to the following embodiments, and the present invention relates to relevant necessary components in the technical field, which should be regarded as the known technology in the technical field and can be known and mastered by the technical personnel in the technical field.

[0017] A method for preparing a camellia oleifera shell biopesticide comprises the following steps: S1. Crush camellia oleifera shells to obtain camellia oleifera shell powder, and mix the camellia oleifera shell powder with humic acid, lignin sulfonate, microbial agent, and filler to obtain a mixed powder; S2, adding sodium alginate and a dispersant into deionized water, adjusting the pH, and then heating and stirring to dissolve to obtain a sodium alginate solution, and uniformly dispersing the mixed powder in the sodium alginate solution to obtain a dispersion; S3, dissolving the emulsifier in the vegetable oil to obtain an oil phase solution, uniformly dropping the dispersion into the oil phase solution and emulsifying to obtain a mixed emulsion; S4, dissolving chitosan and a cross-linking agent in a dilute acid solvent to obtain a chitosan solution, uniformly dispersing the chitosan solution in a mixed emulsion to obtain a cross-linked emulsion, and continuously stirring the cross-linked emulsion to allow sodium alginate and chitosan to undergo a cross-linking reaction to form a capsule wall material, wherein the capsule wall material wraps the mixed powder and together forms a biopesticide capsule; S5. After the sodium alginate and chitosan in the cross-linked emulsion have completed the reaction, the solution is filtered, and the solid product obtained by filtration is washed and dried to obtain a biopesticide, which is composed of a plurality of biopesticide capsules.

[0018] The present invention utilizes camellia oleifera shells to prepare biological pesticides. During the preparation of the biological pesticides, the camellia oleifera shells are used as one of the main raw materials. In step S1, the mixed powder comprises the following components by mass percentage: 50%-70% of camellia oleifera shell powder, 10%-20% of humic acid, 5%-15% of lignin sulfonate, 5%-15% of microbial agent, and 3%-7% of filler. The biological pesticides of the present invention are applied to the soil surface around crops, and can also be mixed with the soil during the process of tilling the soil. The effective ingredients in the components of the biological pesticides are slowly released in the soil to achieve insecticidal and antibacterial effects, and at the same time have the effects of promoting crop growth, improving the soil environment, and preventing soil compaction.

[0019] In step S1 of the present invention, the camellia oleifera shell is washed, dried and then crushed to obtain the camellia oleifera shell powder. After washing, the harmful bacteria, pest eggs and other impurities on the surface of the camellia oleifera shell can be removed to prevent the camellia oleifera shell from mixing these impurities into the biological pesticide and affecting the effect of the biological pesticide. In addition, after the camellia oleifera shell is crushed to form the camellia oleifera shell powder, it has a larger specific surface area, so that the biologically active components in the camellia oleifera shell are more easily released for antibacterial and insecticidal purposes. The camellia oleifera shell powder is also easier to be mixed with other components for processing, thereby improving the processing performance.

[0020] Furthermore, humic acid is a natural organic substance that is non-toxic, harmless, biodegradable, and will not pollute the environment. It meets the requirements of green agriculture and sustainable development. Humic acid contains a variety of functional groups such as carboxyl and phenolic hydroxyl groups. These functional groups can interact with the biologically active components in the oil tea shell to improve the insecticidal and antibacterial effects of biological pesticides. Humic acid also has a good soil improvement effect, which can increase the organic matter content of the soil, improve the soil structure, and combine with heavy metal ions in the soil to reduce the pollution of heavy metals to the soil, and improve the soil's water and fertilizer retention capacity and air permeability. In addition, humic acid contains a variety of nutrients and bioactive substances that are beneficial to crop growth, which can promote the root development and photosynthesis of crops, and improve the disease resistance and stress resistance of crops; lignin sulfonic acid Salt is a natural polymer compound, which is non-toxic, harmless, biodegradable and will not pollute the environment. Lignin sulfonate can work synergistically with other components to improve the effect of biological pesticides. Among them, lignin sulfonate has strong dispersibility and wetting properties. Lignin sulfonate can form a colloidal protective layer in the solution, which is wrapped on the surface of the mixed powder to prevent coagulation and stratification. It can effectively disperse the mixed powder evenly in the sodium alginate solution and form a stable suspension, thereby improving the uniformity and stability of the components in the mixed powder in the biological pesticide. After the application of the biological pesticide, the dispersing and wetting effects of lignin sulfonate can make the active ingredients in the biological pesticide more evenly distributed in the soil, reduce the loss and waste of the active ingredients in the biological pesticide and improve the utilization rate and control effect.

[0021] Furthermore, the filler is selected from one or more of diatomaceous earth powder, bentonite powder, perlite powder, activated carbon powder, zeolite powder, and kaolin powder; the filler of the present invention is used to improve soil structure and reduce soil compaction. Diatomaceous earth powder, bentonite powder, perlite powder, activated carbon powder, zeolite powder, and kaolin powder all have high specific surface area, developed pore structure, excellent adsorption performance, good water retention and other properties. The filler can firmly adsorb other ingredients in the mixed powder, slowly release the active ingredients in the biological pesticide, and improve the durability and uniformity of the efficacy of the biological pesticide.

[0022] Furthermore, the microbial agent is selected from one or more of Trichoderma powder, white rot fungus powder, Bacillus powder, actinomycete powder, Paecilomyces lilacinus powder, Ascosporium powder, and Thomsonii polychaete powder; wherein Trichoderma and white rot fungi are mainly used for soil improvement and biological control, and can decompose organic matter, promote soil microbial activity and inhibit the growth of pathogens; Bacillus has strong stress resistance and adaptability, can produce a variety of antibacterial substances and has control effects on a variety of pathogens and pests; actinomycetes can produce biologically active substances such as antibiotics, and have a significant inhibitory effect on pathogens and pests in the soil; Paecilomyces lilacinus has multiple functions such as improving soil environment, promoting plant growth, and improving plant resistance; Ascosporium is mainly used as an insect pathogenic fungus and is used to control pests, and has the advantages of a unique infection mechanism and the host is not easy to develop resistance; Thomsonii polychaete can be used as an insect pathogenic fungus, has control effects on a variety of pests and is widely parasitic; the microbial agent of the present invention can select appropriate strains for compounding according to the characteristics of crops, thereby achieving efficient biological control.

[0023] In step S2 of the present invention, sodium alginate and a dispersant are added to deionized water, the pH is adjusted to 5-6 by acetic acid, and then heated to 60-80° C., stirred and dissolved to obtain a sodium alginate solution, wherein the mass percentage of sodium alginate in the sodium alginate solution is 1%; the sodium alginate solution is mainly composed of sodium alginate and deionized water, and acetic acid is added to the deionized water to adjust the pH to 5-6 to promote the dissolution of sodium alginate, and then heated to 60-80° C. to further promote the dissolution of sodium alginate, thereby forming a sodium alginate solution with a mass concentration of 1%. The sodium alginate solution can be prepared by heating, and the viscosity of the sodium alginate solution can be reduced. At the same time, under the action of the dispersant, the mixed powder can be more easily dispersed evenly in the sodium alginate solution to obtain a dispersion. The mixed powder in the dispersion is evenly suspended in the sodium alginate solution, which is beneficial to the subsequent biological pesticide capsules. Each component in the mixed powder is evenly dispersed in the biological pesticide capsules. After the biological pesticide is applied, the effective ingredients therein can be more evenly distributed in the soil, thereby reducing the loss and waste of the effective ingredients in the biological pesticide and improving the utilization rate and control effect.

[0024] Furthermore, the mass ratio of the mixed powder, the sodium alginate solution and the dispersant in the dispersion is 1:(1-3):0.05; the dispersant is selected from one of carboxymethyl cellulose, xanthan gum and alkyl glycoside; carboxymethyl cellulose is a cellulose derivative with good water solubility, thickening and dispersibility, and can be adsorbed on the surface of the powder particles of each component in the mixed powder to form a protective film and reduce the agglomeration between the powder particles; xanthan gum is a natural polysaccharide produced by microbial fermentation, and has good thickening, suspension and stability, and can form a high-viscosity solution in deionized water, which helps the mixed powder particles to be suspended in the sodium alginate solution and improve the dispersibility; alkyl glycoside can be used as a bio-based surfactant with low toxicity and good biodegradability, and can effectively reduce the surface tension of the solution and improve the dispersibility of the mixed powder.

[0025] In step S3 of the present invention, the mixed emulsion includes the following components by mass percentage: 50% to 70% vegetable oil, 2% to 4% emulsifier, and 25% to 50% dispersion liquid; the mixed emulsion uses vegetable oil as the oil phase and as the continuous phase, and the dispersion liquid forms droplets dispersed in the vegetable oil under the action of the emulsifier; the vegetable oil is used as the oil phase in the mixed emulsion and is selected from soybean oil, corn oil, sunflower oil, and palm oil, and has the characteristics of being natural, non-toxic, and low-cost, and has good biocompatibility and degradability. The vegetable oil and the dispersion liquid are emulsified into a mixed emulsion under the action of the emulsifier, and the dispersion liquid is coated with a mixed powder by a sodium alginate solution and forms a plurality of small droplets in the continuous phase formed by the vegetable oil. These small droplets serve as precursors of subsequent biological pesticide capsules, which are conducive to obtaining biological pesticide capsules of the mixed powder coated with sodium alginate in the subsequent steps.

[0026] Furthermore, the emulsifier is selected from one of lecithin, phytosterol esters, and sodium starch octenyl succinate; lecithin is a phospholipid compound extracted from natural substances such as egg yolk and soybeans, has good emulsifying properties, biocompatibility and degradability, and is environmentally friendly; phytosterol esters are compounds obtained by esterification reaction of plant sterols and fatty acids, have good emulsifying properties, biocompatibility, degradability, good chemical stability, are environmentally friendly and help maintain their emulsifying effect during the emulsification process; the unique molecular structure of sodium starch octenyl succinate enables it to form a tough film at the oil-water interface, effectively preventing the aggregation and separation of dispersed phase particles, thereby improving the stability of the pesticide emulsion, and sodium starch octenyl succinate is non-toxic, odorless, colorless and easily biodegradable, and is environmentally friendly.

[0027] In step S4 of the present invention, the dilute acid solution is selected to be an acetic acid solution with a mass percentage of 1%. The 1% acetic acid solution can well dissolve chitosan to form a chitosan solution, and the mass percentage of chitosan in the chitosan solution is 5%. Then, the chitosan solution is atomized into small droplets by an atomizing device and then sprayed into the mixed emulsion. The mass ratio of chitosan, cross-linking agent and sodium alginate in the cross-linked emulsion is 1: (0.01-0.03): 1. Since the chitosan solution and the dispersion liquid both use deionized water as solvent, the two have good compatibility. During the stirring process, the small droplets formed by the chitosan solution will gradually mix with the small droplets formed by the dispersion liquid. Then, under the action of the cross-linking agent, the chitosan and the sodium alginate undergo a cross-linking reaction and solidify to form a capsule wall material. The solidified capsule wall material wraps the mixed powder inside and together forms a biological pesticide capsule.

[0028] Furthermore, the cross-linking agent is selected from one of genipin, inorganic calcium salt and inorganic zinc salt; genipin is a natural cross-linking agent extracted from gardenia fruit, has good biocompatibility and degradability, and can be used as a safe and environmentally friendly cross-linking agent for the cross-linking reaction of chitosan and sodium alginate; inorganic calcium salt and inorganic zinc salt can form calcium ions and zinc ions respectively in the solution, and these ions can form a cross-linked structure by ion exchange or coordination with functional groups such as amino groups and carboxyl groups in chitosan and sodium alginate; by using a cross-linking agent to react chitosan with sodium alginate to form a capsule wall material with a cross-linked structure, the strength and stability of the surface of the biological pesticide capsule can be improved, and it is also helpful to control the release rate of the active ingredients in the mixed powder, thereby improving the utilization efficiency and durability of the biological pesticide.

[0029] In summary, the present invention uses oil tea shell as the main raw material to prepare biological pesticides, utilizes the biologically active ingredients in the oil tea shell to inhibit bacteria and kill insects, and improves the antibacterial and insecticidal effects by compounding with humic acid, lignin sulfonate, and microbial agents. It has the functions of increasing the organic matter content of the soil, improving the soil structure, preventing soil compaction, promoting the growth of beneficial bacteria in the soil, and promoting the growth of crops. In addition, the mixed powder is wrapped in the capsule wall material with a cross-linked structure formed by chitosan and sodium alginate to prepare a biological pesticide capsule. After the biological pesticide capsule is applied to the soil, the effective ingredients therein are gradually released in the soil through the slow-release mixed powder, thereby improving the utilization efficiency and durability of the biological pesticide.

[0030] The present invention is further described below by way of examples and comparative examples.

[0031] Example 1

[0032] S1. Crush the camellia oleifera shell to obtain camellia oleifera shell powder, and mix the camellia oleifera shell powder with humic acid, lignin sulfonate, microbial agent, and diatomaceous earth powder to obtain a mixed powder; the mixed powder comprises the following components by mass percentage: 60% camellia oleifera shell powder, 15% humic acid, 10% lignin sulfonate, 10% microbial agent, and 5% diatomaceous earth powder; S2, adding sodium alginate and carboxymethyl cellulose to deionized water, adjusting the pH to 5.5 with acetic acid, and then heating to 80° C. and stirring to dissolve to obtain a sodium alginate solution, and uniformly dispersing the mixed powder in the sodium alginate solution to obtain a dispersion; the mass ratio of the mixed powder, sodium alginate solution, and carboxymethyl cellulose in the dispersion is 1:2:0.05; S3, dissolving lecithin in vegetable oil to obtain an oil phase solution, uniformly dropping the dispersion into the oil phase solution and emulsifying to obtain a mixed emulsion; the mixed emulsion includes the following components by mass percentage: 57% vegetable oil, 3% lecithin, and 40% dispersion; S4, dissolving chitosan and genipin in 1% by mass acetic acid solution to obtain a chitosan solution, uniformly dispersing the chitosan solution in a mixed emulsion to obtain a cross-linked emulsion, continuously stirring the cross-linked emulsion to allow sodium alginate and chitosan to undergo a cross-linking reaction to form a capsule wall material, wherein the capsule wall material wraps the mixed powder inside and together forms a biopesticide capsule; the mass ratio of chitosan, genipin, and sodium alginate in the cross-linked emulsion is 1:0.02:1; S5. After the sodium alginate and chitosan in the cross-linked emulsion have completed the reaction, the solution is filtered, and the solid product obtained by filtration is washed and dried to obtain a biopesticide, which is composed of a plurality of biopesticide capsules.

[0033] Comparative Example 1 The crop pest control agent is obtained by referring to the specification of a Chinese patent on a method for controlling crop pests using oil-tea camellia shells (Announcement No.: CN114342963A).

[0034] The same mass of the biological pesticide of Example 1 and the crop pest control agent of Comparative Example 1 were taken to two soils with similar composition for pest and pathogen control tests. The pest control test was conducted on the killing effect of four pests, namely white grubs, wireworms, cutworms and mole crickets. The pathogen control test was conducted on the inhibition effect of three pathogens, namely soft rot pathogens, root rot pathogens and tobacco mosaic virus. The percentage of the reduction in the number of pests and pathogens before and after the test was used as an indicator of the control effect, and the change of the control effect with the increase of the test time was recorded. The test results are shown in Tables 1 and 2 below:

[0035] Table 1

[0036] Table 2 According to the data in Table 1, it can be seen that in Comparative Example 1, a high control effect can be quickly achieved in the initial stage of the pest control test, and the best control effect is achieved at about 15 days, but the control effect is significantly reduced after 30 days; in Example 1, although the control effect is poor in the initial stage of the pest control test, the control effect exceeds that of Comparative Example 1 at about 15 days, and the best control effect is achieved at about 30 days, and the pest control effect of more than 80% can be maintained within 50 days, and the pest control effect is better and lasts longer.

[0037] According to the data in Table 2, it can be seen that in Comparative Example 1, a high control effect can be quickly achieved in the initial stage of the pathogen control test, and the best control effect is achieved at about 15 days, but the control effect is significantly reduced after 40 days; in Example 1, although the control effect is poor in the initial stage of the pathogen control test, the control effect exceeds Comparative Example 1 and reaches the best control effect at about 15 days, and the pathogen control effect of more than 90% can be maintained within 50 days, the pathogen control effect is better and the control duration is longer.

[0038] It can be seen that Example 1 based on the scheme of the present invention has better control effect and control duration on pests and pathogens. This is because when the present invention utilizes the camellia oleifera shell, it does not extract its biologically active components, which can well ensure the quality and activity of these components, thereby having a better control effect, and these components are controlled by sustained release to control pests and pathogens, thereby having a more lasting control effect.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a camellia oleifera shell biopesticide, It is characterized in that The following steps are involved: S1. Crush camellia oleifera shells to obtain camellia oleifera shell powder, and mix the camellia oleifera shell powder with humic acid, lignin sulfonate, microbial agent, and filler to obtain a mixed powder; S2, adding sodium alginate and a dispersant into deionized water, adjusting the pH, and then heating and stirring to dissolve to obtain a sodium alginate solution, and uniformly dispersing the mixed powder in the sodium alginate solution to obtain a dispersion; S3, dissolving the emulsifier in the vegetable oil to obtain an oil phase solution, uniformly dropping the dispersion into the oil phase solution and emulsifying to obtain a mixed emulsion; S4, dissolving chitosan and a cross-linking agent in a dilute acid solvent to obtain a chitosan solution, uniformly dispersing the chitosan solution in a mixed emulsion to obtain a cross-linked emulsion, and continuously stirring the cross-linked emulsion to allow sodium alginate and chitosan to undergo a cross-linking reaction to form a capsule wall material, wherein the capsule wall material wraps the mixed powder and together forms a biopesticide capsule; S5. After the sodium alginate and chitosan in the cross-linked emulsion have completed the reaction, the solution is filtered, and the solid product obtained by filtration is washed and dried to obtain a biopesticide, which is composed of a plurality of biopesticide capsules.

2. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The mixed powder comprises the following components by mass percentage: 50%-70% of camellia oleifera shell powder, 10%-20% of humic acid, 5%-15% of lignin sulfonate, 5%-15% of microbial agent, and 3%-7% of filler; in step S1, the camellia oleifera shell is washed, dried, and then crushed to obtain the camellia oleifera shell powder.

3. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The microbial agent is selected from one or more of Trichoderma powder, white rot fungus powder, Bacillus powder, actinomycete powder, Paecilomyces lilacinus powder, Ascochyta powder, and Polychaeta tomophila powder.

4. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The filler is selected from one or more of diatomaceous earth powder, bentonite powder, perlite powder, activated carbon powder, zeolite powder and kaolin powder.

5. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that In step S2, sodium alginate and a dispersant are added to deionized water, the pH is adjusted to 5-6 by acetic acid, and then heated to 60-80° C. and stirred to dissolve to obtain a sodium alginate solution, wherein the mass percentage of sodium alginate in the sodium alginate solution is 1%.

6. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The mass ratio of the mixed powder, the sodium alginate solution and the dispersant in the dispersion is 1:(1-3):0.05; the dispersant is selected from one of carboxymethyl cellulose, xanthan gum and alkyl glycoside.

7. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The mixed emulsion includes the following components by mass percentage: 50% to 70% vegetable oil, 2% to 4% emulsifier, and 25% to 50% dispersion liquid; the vegetable oil is selected from soybean oil, corn oil, sunflower oil, and palm oil; the emulsifier is selected from lecithin, plant sterol esters, and sodium starch glycolate.

8. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that In step S3, the mixed emulsion uses vegetable oil as the oil phase and as the continuous phase, and the dispersion forms droplets dispersed in the vegetable oil under the action of an emulsifier.

9. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that In step S4, the dilute acid solution is selected from 1% by mass acetic acid solution, the mass percentage of chitosan in the chitosan solution is 5%, and the cross-linking agent is selected from one of genipin, inorganic calcium salt, and inorganic zinc salt.

10. The method for preparing the camellia oleifera shell biopesticide according to claim 1, It is characterized in that The mass ratio of chitosan, crosslinking agent and sodium alginate in the crosslinked emulsion is 1:(0.01-0.03):1.

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