Botanical fungicide and application thereof

Abstract

The invention discloses a botanical fungicide and application thereof, and relates to the technical field of fungicides, the botanical fungicide comprises the following raw materials: modified allicin, modified carvacrol, physcion, Arabic gum, azone, an emulsifier, propylene glycol and deionized water; through the synergistic effect of the modified allicin and the Arabic gum, the Arabic gum forms a breathable protective film on the surfaces of crops, active ingredients are firmly fixed, ingredient loss caused by rain wash and high-temperature evaporation in rainy seasons is reduced, the rain wash resistance is improved, ultraviolet irradiation can be synergistically blocked, the modified allicin is protected from photo-thermal oxidation damage, and the crop quality is improved. The preparation has the advantages that the stability of the preparation is enhanced, the burn and malformation risks in the young fruit stage and the flowering stage of the fruits can be effectively reduced, and the two components are plant source natural components, so that the targeted bacteriostasis and long-acting prevention and control effects are enhanced when the two components act synergistically; the added modified carvacrol and modified allicin have a synergistic effect, so that a stable control effect can still be maintained in severe environments such as high temperature, strong light, rainy seasons and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fungicides, in particular to a plant source fungicide and application thereof. BACKGROUND

[0002] Fungicides are a class of chemical substances or biological agents used for preventing, killing or inhibiting the growth of harmful microorganisms.

[0003] Traditional plant source fungicides have poor stability, short shelf life, slow effect, short effective period and weak rainwater erosion resistance, which seriously restricts their prevention effect and popularization and application. In application, they are easy to cause phytotoxicity to sensitive tissues such as young fruits and flowering of fruits, and have common problems such as narrow fungistatic spectrum of single component and easy induction of pathogenic bacteria to produce drug resistance. Based on this, the present application provides a plant source fungicide and application thereof. SUMMARY

[0004] The main purpose of the present application is to provide a plant source fungicide with long effective period and high rainwater erosion resistance, which is applied to a plant source fungicide.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: The present application provides a plant source fungicide, which comprises the following component raw materials: 1-1.5 parts of modified allicin, 2.5-3.5 parts of modified carvacrol, 0.6-1 part of physcion, 1.2-1.8 parts of gum arabic, 0.6-1 part of laurocapram, 2.5-3.5 parts of emulsifier, 5-7 parts of propylene glycol and 75-85 parts of deionized water. The preparation of the plant source fungicide comprises the following steps: S1. Modified allicin, modified carvacrol, physcion, propylene glycol and emulsifier are added into a reaction kettle for stirring, the temperature is set to 45-55 DEG C, the rotation speed is set to 250-300 rpm, and stirring is performed for 10-15 minutes to obtain solution A; S2. Gum arabic, laurocapram and deionized water are added into a reaction kettle for stirring, the temperature is set to 40-45 DEG C, the rotation speed is set to 200-250 rpm, and stirring is performed for 8-10 minutes to obtain solution B; S3. Solution A is added into a high-speed emulsifier for emulsification, the rotation speed is set to 8000-10000 rpm, solution B is added for emulsification, the rotation speed is set to 8000-10000 rpm, and emulsification is performed for 5-8 minutes to obtain a mixed liquid, the mixed liquid is placed into an ultrasonic disperser for dispersion, the power is set to 300-400 W, and dispersion is performed for 10-15 minutes to obtain an emulsion, the emulsion is added into a reaction kettle for stirring, the rotation speed is set to 200 rpm, a pH adjuster is added, stirring is performed for 15-20 minutes, and standing is performed for 24 hours to obtain the plant source fungicide.

[0006] The gum arabic is food grade, with a viscosity of 200-300 mPa·s; The purity of rhein methyl ether is ≥95%; Lauryl azone is food grade with a purity of ≥98%. Propylene glycol is food grade with a purity of ≥99.5%. Gum arabic can work synergistically with emulsifiers to reduce oil-water interfacial tension, maintain the uniformity and stability of microemulsion formulations, and prevent stratification and sedimentation. As a skin protectant, its natural and mild properties can form a breathable protective film on crop surfaces, reducing the stimulation of active ingredients on sensitive tissues such as young fruits and flowering periods of high-grade fruits, and reducing the risk of scorching and deformities. As an adhesive, its strong hydrophilicity and adhesion can enhance the binding force between the pesticide and the crop surface, resist rain erosion, reduce the loss of active ingredients, improve the rain resistance of the formulation, and ensure that it can maintain stable efficacy even after rain shortly after spraying during the rainy season.

[0007] The action of emodin methyl ether is to inhibit the activity of pathogen cell wall synthases, blocking mycelial growth and spore germination. It forms a synergistic system with modified carvacrol and modified allicin, which not only broadens the antifungal spectrum of fungicides, but also has a good inhibitory effect on various diseases such as powdery mildew and anthracnose. It can also enhance the control ability against drug-resistant strains. Through synergistic effect with the core modified components, it further improves the overall control efficacy, reduces the dosage of single components, reduces the risk of pathogen resistance, and maintains the plant-derived properties.

[0008] Further, the pH adjuster in S3 is either a 0.05 mol / L citric acid aqueous solution or a 0.05 mol / L sodium hydroxide aqueous solution; The pH is adjusted to 6-7 by adding a pH adjuster.

[0009] Furthermore, the emulsifier is a mixture of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester; The mass ratio of the polyoxyethylene sorbitan monooleate to the sorbitan fatty acid ester is 2:1.

[0010] The lipophilicity of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester in the emulsifier complements each other, ensuring that the formulation does not have stratification or precipitation after storage, transportation and dilution, and the particle size is stable in the range of 100-200nm. This not only ensures the uniformity of droplets during spraying, but also promotes the dispersion and adsorption of active ingredients on the crop surface, providing a formulation basis for the core ingredients to exert their antibacterial effect. Furthermore, the preparation of the modified allicin includes the following steps: A1. Add zinc chloride and deionized water into the reaction vessel and stir. Set the speed to 200-250 rpm and stir for 10-15 minutes to obtain a zinc chloride solution. A2. Add allicin and remaining deionized water to the reaction vessel and stir. Set the temperature to 30-38℃ and the rotation speed to 200-350 rpm for 25-35 minutes. Add zinc chloride solution and stir. Set the rotation speed to 200-250 rpm. Add citric acid aqueous solution and stir for 25-35 minutes. Add chitosan powder and stir. Set the temperature to 45-55℃ and the rotation speed to 300-350 rpm for 40-60 minutes to obtain a mixture. Allow the mixture to cool naturally to 25℃. Centrifuge the mixture in a high-speed centrifuge. Set the rotation speed to 3500-4500 rpm for 8-12 minutes. Collect the precipitate and wash it 2-3 times with deionized water. After each wash, centrifuge for 5 minutes. Place the washed precipitate in a vacuum drying oven and dry it. Set the temperature to 40-48℃ and the vacuum degree to 0.07-0.09 MPa for 5-7 hours to obtain modified allicin.

[0011] Allicin purity ≥ 95%; Zinc chloride is food grade with a purity of ≥98%. Chitosan has a degree of deacetylation of 80%-90%, a molecular weight of 40,000-60,000, and a particle size of 30-40 μm. Furthermore, an aqueous solution of citric acid is added to A2 to adjust the pH to 4.5-5.5; The concentration of the citric acid aqueous solution is 0.05 mol / L.

[0012] Furthermore, the mass ratio of zinc chloride to deionized water in A1 is 1:31.25.

[0013] Furthermore, the mass ratio of allicin, remaining deionized water, zinc chloride solution and chitosan powder in A2 is 5:12.5:12.6:1.

[0014] Furthermore, the preparation of the modified carvacrol includes the following steps: B1. Add carvacrol, glycerol and anhydrous ethanol to the reaction vessel and stir. Set the temperature to 45-55℃ and the speed to 200-250 rpm. Stir for 8-12 minutes. Add urea powder and stir for 5-10 minutes to obtain carvacrol mixture. Add the carvacrol mixture to an ultrasonic disperser and disperse for 10-15 minutes. Obtain solution C. B2. Add β-cyclodextrin and deionized water to the reactor and stir. Set the water bath temperature to 75-85℃ and the stirring speed to 300-400 rpm. Stir for 15-20 minutes, then stop heating and allow the reactor to cool naturally to 35-45℃. Add solution C and stir. Set the stirring speed to 300-400 rpm and stir for 1.5-2.5 hours. Allow the reactor to cool naturally to 25℃ and adjust the stirring speed to 200 rpm. Add polyethylene glycol 400 and stir for 10-15 minutes. Dry using a spray dryer with an inlet temperature of 110-130℃ and an outlet temperature of 65-75℃ to obtain modified carvacrol.

[0015] Carvacrol purity ≥ 96%; The urea is food grade with a purity of ≥99%. The glycerin is food grade with a purity of ≥99.5%. β-Cyclodextrin is food grade with a particle size ≤0.1mm; Polyethylene glycol 400 is food grade with a purity of ≥99%. Furthermore, the mass ratio of carvacrol, urea powder, glycerin, anhydrous ethanol, β-cyclodextrin, deionized water and polyethylene glycol 400 is 1:0.2:0.045:1.5:1.5:5:0.045.

[0016] Furthermore, a plant-derived fungicide is suitable for preventing damping-off, seedling blight, and root rot in strawberry seedlings, cucumber seedlings, tomato seedlings, and flower seedlings.

[0017] The present invention has the following beneficial effects: 1. In this invention, modified carvacrol is added. Through hydrogen bond pre-assembly and inclusion with β-cyclodextrin, the composite modification optimizes the molecular conformation to enhance lipid solubility and cell membrane penetration ability. It also avoids photothermal oxidative degradation by utilizing the hydrophobic cavity of cyclodextrin, significantly improving stability and penetration efficiency. It can specifically inhibit the growth and reproduction of pathogens. By efficiently penetrating the crop cuticle and accumulating in the target area, it quickly destroys the integrity of pathogen cell membranes. At the same time, it synergistically enhances with modified allicin, prolonging the duration of effect and ensuring stable efficacy even under harsh environments such as high temperature, strong light, and rainy season. Moreover, its plant-derived nature ensures safety for fruits.

[0018] 2. In this invention, modified allicin is added. After being modified by metal ion coordination and chitosan composite modification, the disulfide bond is linked to Zn. 2+ Forming coordination bonds provides stability and protection, preventing premature degradation. Chitosan, on the other hand, endows it with targeted sustained-release function. Its core role is to accurately identify and bind to negatively charged groups on the surface of pathogens, enriching allicin in the target area and releasing it slowly, thereby disrupting the energy metabolism and reproduction processes of pathogens. Simultaneously, Zn... 2+It produces a synergistic antibacterial effect with allicin, greatly enhancing the prevention and treatment of diseases. The plant-derived properties of chitosan can also enhance the skin-protecting properties of the preparation, avoiding irritation to young fruits and flowering tissues.

[0019] 3. In this invention, through the synergistic effect of modified allicin and gum arabic, gum arabic forms a breathable protective film on the crop surface, firmly fixing the active ingredients. This reduces the loss of ingredients caused by rainwater erosion and high-temperature evaporation during the rainy season, significantly improving rain resistance. It also synergistically blocks ultraviolet radiation, protecting modified allicin from photo-thermal oxidation and enhancing the stability of the formulation. The mild film-forming properties of gum arabic can form a buffer layer between modified allicin and sensitive tissues of the crop, synergistically with the chitosan-protective effect of modified allicin, avoiding excessively high local concentrations of active ingredients that irritate the fruit peel. This effectively reduces the risk of scorching and deformity during the young fruit and flowering stages. Both are plant-derived natural components, and their synergistic effect strengthens the targeted antibacterial and long-term control effects while maintaining the core attributes of the formulation being green and low in toxicity, thus meeting the safe application requirements of high-value crops. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all raw materials used in the following experiments are commercially available.

[0022] Example 1: A plant-derived fungicide, comprising the following components: 1 part modified allicin, 2.5 parts modified carvacrol, 0.6 parts emodin methyl ether, 1.2 parts gum arabic, 0.6 parts lauryl azone, 2.5 parts emulsifier, 5 parts propylene glycol, and 75 parts deionized water; The preparation of plant-derived fungicides includes the following steps: S1. Add modified allicin, modified carvacrol, emodin methyl ether, propylene glycol and emulsifier into the reaction vessel and stir. Set the temperature to 45-55℃, the rotation speed to 250-300 rpm, and stir for 10-15 minutes to obtain solution A. S2. Add gum arabic, lauryl azone and deionized water into the reaction vessel and stir. Set the temperature to 40-45℃ and the speed to 200-250 rpm. Stir for 8-10 minutes to obtain solution B. S3. Add solution A to a high-speed emulsifier and emulsify at a speed of 8000-10000 rpm. Add solution B and emulsify at a speed of 8000-10000 rpm for 5-8 minutes to obtain a mixture. Place the mixture in an ultrasonic disperser and disperse at a power of 300-400W for 10-15 minutes to obtain an emulsion. Add the emulsion to a reaction vessel and stir at a speed of 200 rpm. Add a pH adjuster and stir for 15-20 minutes. Let it stand for 24 hours to obtain a plant-derived fungicide.

[0023] The pH adjuster in S3 is either a 0.05 mol / L citric acid aqueous solution or a 0.05 mol / L sodium hydroxide aqueous solution; Add a pH adjuster to adjust the pH to 6-7.

[0024] The emulsifier is a mixture of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester; The mass ratio of the polyoxyethylene sorbitan monooleate to the sorbitan fatty acid ester is 2:1.

[0025] The preparation of modified allicin includes the following steps: A1. Add zinc chloride and deionized water into the reaction vessel and stir. Set the speed to 200-250 rpm and stir for 10-15 minutes to obtain a zinc chloride solution. A2. Add allicin and remaining deionized water to the reaction vessel and stir. Set the temperature to 30-38℃ and the rotation speed to 200-350 rpm for 25-35 minutes. Add zinc chloride solution and stir. Set the rotation speed to 200-250 rpm. Add citric acid aqueous solution and stir for 25-35 minutes. Add chitosan powder and stir. Set the temperature to 45-55℃ and the rotation speed to 300-350 rpm for 40-60 minutes to obtain a mixture. Allow the mixture to cool naturally to 25℃. Centrifuge the mixture in a high-speed centrifuge. Set the rotation speed to 3500-4500 rpm for 8-12 minutes. Collect the precipitate and wash it 2-3 times with deionized water. After each wash, centrifuge for 5 minutes. Place the washed precipitate in a vacuum drying oven and dry it. Set the temperature to 40-48℃ and the vacuum degree to 0.07-0.09 MPa for 5-7 hours to obtain modified allicin.

[0026] Add citric acid aqueous solution to A2 to adjust the pH to 4.5-5.5; The concentration of the citric acid aqueous solution is 0.05 mol / L.

[0027] The mass ratio of zinc chloride to deionized water in A1 is 1:31.25.

[0028] The mass ratio of allicin, remaining deionized water, zinc chloride solution, and chitosan powder in A2 is 5:12.5:12.6:1.

[0029] The preparation of modified carvacrol includes the following steps: B1. Add carvacrol, glycerol and anhydrous ethanol to the reaction vessel and stir. Set the temperature to 45-55℃ and the speed to 200-250 rpm. Stir for 8-12 minutes. Add urea powder and stir for 5-10 minutes to obtain carvacrol mixture. Add the carvacrol mixture to an ultrasonic disperser and disperse for 10-15 minutes. Obtain solution C. B2. Add β-cyclodextrin and deionized water to the reactor and stir. Set the water bath temperature to 75-85℃ and the stirring speed to 300-400 rpm. Stir for 15-20 minutes, then stop heating and allow the reactor to cool naturally to 35-45℃. Add solution C and stir. Set the stirring speed to 300-400 rpm and stir for 1.5-2.5 hours. Allow the reactor to cool naturally to 25℃ and adjust the stirring speed to 200 rpm. Add polyethylene glycol 400 and stir for 10-15 minutes. Dry using a spray dryer with an inlet temperature of 110-130℃ and an outlet temperature of 65-75℃ to obtain modified carvacrol.

[0030] The mass ratio of carvacrol, urea powder, glycerin, anhydrous ethanol, β-cyclodextrin, deionized water and polyethylene glycol 400 is 1:0.2:0.045:1.5:1.5:5:0.045.

[0031] A plant-derived fungicide is suitable for preventing damping-off, seedling blight, and root rot in strawberry seedlings, cucumber seedlings, tomato seedlings, and flower seedlings.

[0032] Example 2: A plant-derived fungicide, comprising the following components: 1.25 parts modified allicin, 3 parts modified carvacrol, 0.8 parts emodin methyl ether, 1.5 parts gum arabic, 0.8 parts lauryl azone, 3 parts emulsifier, 6 parts propylene glycol, and 80 parts deionized water; The preparation of plant-derived fungicides includes the following steps: S1. Add modified allicin, modified carvacrol, emodin methyl ether, propylene glycol and emulsifier into the reaction vessel and stir. Set the temperature to 45-55℃, the rotation speed to 250-300 rpm, and stir for 10-15 minutes to obtain solution A. S2. Add gum arabic, lauryl azone and deionized water into the reaction vessel and stir. Set the temperature to 40-45℃ and the speed to 200-250 rpm. Stir for 8-10 minutes to obtain solution B. S3. Add solution A to a high-speed emulsifier and emulsify at a speed of 8000-10000 rpm. Add solution B and emulsify at a speed of 8000-10000 rpm for 5-8 minutes to obtain a mixture. Place the mixture in an ultrasonic disperser and disperse at a power of 300-400W for 10-15 minutes to obtain an emulsion. Add the emulsion to a reaction vessel and stir at a speed of 200 rpm. Add a pH adjuster and stir for 15-20 minutes. Let it stand for 24 hours to obtain a plant-derived fungicide.

[0033] The pH adjuster in S3 is either a 0.05 mol / L citric acid aqueous solution or a 0.05 mol / L sodium hydroxide aqueous solution; Add a pH adjuster to adjust the pH to 6-7.

[0034] The emulsifier is a mixture of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester; The mass ratio of polyoxyethylene sorbitan monooleate to sorbitan fatty acid ester is 2:1.

[0035] The preparation of modified allicin includes the following steps: A1. Add zinc chloride and deionized water into the reaction vessel and stir. Set the speed to 200-250 rpm and stir for 10-15 minutes to obtain a zinc chloride solution. A2. Add allicin and remaining deionized water to the reaction vessel and stir. Set the temperature to 30-38℃ and the rotation speed to 200-350 rpm for 25-35 minutes. Add zinc chloride solution and stir. Set the rotation speed to 200-250 rpm. Add citric acid aqueous solution and stir for 25-35 minutes. Add chitosan powder and stir. Set the temperature to 45-55℃ and the rotation speed to 300-350 rpm for 40-60 minutes to obtain a mixture. Allow the mixture to cool naturally to 25℃. Centrifuge the mixture in a high-speed centrifuge. Set the rotation speed to 3500-4500 rpm for 8-12 minutes. Collect the precipitate and wash it 2-3 times with deionized water. After each wash, centrifuge for 5 minutes. Place the washed precipitate in a vacuum drying oven and dry it. Set the temperature to 40-48℃ and the vacuum degree to 0.07-0.09 MPa for 5-7 hours to obtain modified allicin.

[0036] Add citric acid aqueous solution to A2 to adjust the pH to 4.5-5.5; The concentration of the citric acid aqueous solution is 0.05 mol / L.

[0037] The mass ratio of zinc chloride to deionized water in A1 is 1:31.25.

[0038] The mass ratio of allicin, remaining deionized water, zinc chloride solution, and chitosan powder in A2 is 5:12.5:12.6:1.

[0039] The preparation of modified carvacrol includes the following steps: B1. Add carvacrol, glycerol and anhydrous ethanol to the reaction vessel and stir. Set the temperature to 45-55℃ and the speed to 200-250 rpm. Stir for 8-12 minutes. Add urea powder and stir for 5-10 minutes to obtain carvacrol mixture. Add the carvacrol mixture to an ultrasonic disperser and disperse for 10-15 minutes. Obtain solution C. B2. Add β-cyclodextrin and deionized water to the reactor and stir. Set the water bath temperature to 75-85℃ and the stirring speed to 300-400 rpm. Stir for 15-20 minutes, then stop heating and allow the reactor to cool naturally to 35-45℃. Add solution C and stir. Set the stirring speed to 300-400 rpm and stir for 1.5-2.5 hours. Allow the reactor to cool naturally to 25℃ and adjust the stirring speed to 200 rpm. Add polyethylene glycol 400 and stir for 10-15 minutes. Dry using a spray dryer with an inlet temperature of 110-130℃ and an outlet temperature of 65-75℃ to obtain modified carvacrol.

[0040] The mass ratio of carvacrol, urea powder, glycerin, anhydrous ethanol, β-cyclodextrin, deionized water and polyethylene glycol 400 is 1:0.2:0.045:1.5:1.5:5:0.045.

[0041] A plant-derived fungicide is suitable for preventing damping-off, seedling blight, and root rot in strawberry seedlings, cucumber seedlings, tomato seedlings, and flower seedlings.

[0042] Example 3: A plant-derived fungicide, comprising the following components: 1.5 parts modified allicin, 3.5 parts modified carvacrol, 1 part emodin methyl ether, 1.8 parts gum arabic, 1 part lauryl azone, 3.5 parts emulsifier, 7 parts propylene glycol, and 85 parts deionized water; The preparation of plant-derived fungicides includes the following steps: S1. Add modified allicin, modified carvacrol, emodin methyl ether, propylene glycol and emulsifier into the reaction vessel and stir. Set the temperature to 45-55℃, the rotation speed to 250-300 rpm, and stir for 10-15 minutes to obtain solution A. S2. Add gum arabic, lauryl azone and deionized water into the reaction vessel and stir. Set the temperature to 40-45℃ and the speed to 200-250 rpm. Stir for 8-10 minutes to obtain solution B. S3. Add solution A to a high-speed emulsifier and emulsify at a speed of 8000-10000 rpm. Add solution B and emulsify at a speed of 8000-10000 rpm for 5-8 minutes to obtain a mixture. Place the mixture in an ultrasonic disperser and disperse at a power of 300-400W for 10-15 minutes to obtain an emulsion. Add the emulsion to a reaction vessel and stir at a speed of 200 rpm. Add a pH adjuster and stir for 15-20 minutes. Let it stand for 24 hours to obtain a plant-derived fungicide.

[0043] The pH adjuster in S3 is either a 0.05 mol / L citric acid aqueous solution or a 0.05 mol / L sodium hydroxide aqueous solution; Add a pH adjuster to adjust the pH to 6-7.

[0044] The emulsifier is a mixture of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester; The mass ratio of polyoxyethylene sorbitan monooleate to sorbitan fatty acid ester is 2:1.

[0045] The preparation of modified allicin includes the following steps: A1. Add zinc chloride and deionized water into the reaction vessel and stir. Set the speed to 200-250 rpm and stir for 10-15 minutes to obtain a zinc chloride solution. A2. Add allicin and remaining deionized water to the reaction vessel and stir. Set the temperature to 30-38℃ and the rotation speed to 200-350 rpm for 25-35 minutes. Add zinc chloride solution and stir. Set the rotation speed to 200-250 rpm. Add citric acid aqueous solution and stir for 25-35 minutes. Add chitosan powder and stir. Set the temperature to 45-55℃ and the rotation speed to 300-350 rpm for 40-60 minutes to obtain a mixture. Allow the mixture to cool naturally to 25℃. Centrifuge the mixture in a high-speed centrifuge. Set the rotation speed to 3500-4500 rpm for 8-12 minutes. Collect the precipitate and wash it 2-3 times with deionized water. After each wash, centrifuge for 5 minutes. Place the washed precipitate in a vacuum drying oven and dry it. Set the temperature to 40-48℃ and the vacuum degree to 0.07-0.09 MPa for 5-7 hours to obtain modified allicin.

[0046] Add citric acid aqueous solution to A2 to adjust the pH to 4.5-5.5; The concentration of the citric acid aqueous solution is 0.05 mol / L.

[0047] The mass ratio of zinc chloride to deionized water in A1 is 1:31.25.

[0048] The mass ratio of allicin, remaining deionized water, zinc chloride solution, and chitosan powder in A2 is 5:12.5:12.6:1.

[0049] The preparation of modified carvacrol includes the following steps: B1. Add carvacrol, glycerol and anhydrous ethanol to the reaction vessel and stir. Set the temperature to 45-55℃ and the speed to 200-250 rpm. Stir for 8-12 minutes. Add urea powder and stir for 5-10 minutes to obtain carvacrol mixture. Add the carvacrol mixture to an ultrasonic disperser and disperse for 10-15 minutes. Obtain solution C. B2. Add β-cyclodextrin and deionized water to the reactor and stir. Set the water bath temperature to 75-85℃ and the stirring speed to 300-400 rpm. Stir for 15-20 minutes, then stop heating and allow the reactor to cool naturally to 35-45℃. Add solution C and stir. Set the stirring speed to 300-400 rpm and stir for 1.5-2.5 hours. Allow the reactor to cool naturally to 25℃ and adjust the stirring speed to 200 rpm. Add polyethylene glycol 400 and stir for 10-15 minutes. Dry using a spray dryer with an inlet temperature of 110-130℃ and an outlet temperature of 65-75℃ to obtain modified carvacrol.

[0050] The mass ratio of carvacrol, urea powder, glycerin, anhydrous ethanol, β-cyclodextrin, deionized water and polyethylene glycol 400 is 1:0.2:0.045:1.5:1.5:5:0.045.

[0051] A plant-derived fungicide is suitable for preventing damping-off, seedling blight, and root rot in strawberry seedlings, cucumber seedlings, tomato seedlings, and flower seedlings.

[0052] Comparative Example 1: The difference between this comparative example and Example 1 is that: The carvacrol used in this comparative example is unmodified carvacrol.

[0053] Comparative Example 2: The difference between this comparative example and Example 1 is that: The allicin used in this comparative example is unmodified allicin.

[0054] Comparative Example 3 differs from Example 1 in that: This comparative example does not contain gum arabic.

[0055] Performance testing: The plant-derived fungicides prepared in Examples 1, 2, 3, 1, 2, and 3 were tested.

[0056] Performance testing: The relevant performance of the plant-derived fungicide and its application samples provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test data are recorded in Table 1 below:

[0057] Based on the above data, the following conclusions can be drawn: The antibacterial activity of Examples 1-3 after 48 hours of ultraviolet light decreased significantly better than that of Comparative Examples 1-3. The key point is that the examples added modified carvacrol, whose hydrophilic shell can block ultraviolet light from directly irradiating the active site and avoid molecular oxidative degradation; the stable conformation formed by hydrogen bond pre-assembly further enhances the molecular resistance to photolysis.

[0058] (2) The preventive efficacy of Examples 1-3 is far superior to that of Comparative Examples 1-3. The key point is that the examples add modified allicin, which can continuously form an antibacterial protective film, inhibit the germination of pathogenic spores and mycelial invasion, and significantly reduce the initial incidence of disease.

[0059] (3) The efficacy of the spraying of Examples 1-3 was significantly lower than that of Comparative Examples 1-3 when moderate rain (simulated rainfall of 20 mm) occurred 1 hour after application. The key point is that the examples added gum arabic, which is a natural high molecular weight polysaccharide. Gum arabic has strong hydrophilicity and adhesion. After spraying, it can quickly form a uniform and breathable protective film on the crop surface, which firmly adsorbs the active ingredients such as modified carvacrol and modified allicin onto the crop surface, thereby enhancing the binding force between the pesticide and the crop.

[0060] Through the above demonstrations, the present invention is significantly superior to the control group in terms of the decrease in antibacterial activity after 48 hours of ultraviolet light, the preventive effect during the prevention period, and the decrease in preventive effect after 1 hour of moderate rain (simulated rainfall of 20 mm), thus verifying the advanced nature and rationality of the preparation process.

[0061] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A plant-derived fungicide, characterized in that, The plant-derived fungicide comprises the following raw materials: 1-1.5 parts modified allicin, 2.5-3.5 parts modified carvacrol, 0.6-1 part emodin methyl ether, 1.2-1.8 parts gum arabic, 0.6-1 part lauryl azone, 2.5-3.5 parts emulsifier, 5-7 parts propylene glycol, and 75-85 parts deionized water; The preparation of the plant-derived fungicide includes the following steps: S1. Add modified allicin, modified carvacrol, emodin methyl ether, propylene glycol and emulsifier to the reaction vessel and stir to obtain solution A; S2. Add gum arabic, lauryl ketone, and deionized water to the reaction vessel and stir to obtain solution B; S3. Add solution A to a high-speed emulsifier for emulsification, add solution B for emulsification, and obtain a mixture. Place the mixture in an ultrasonic disperser for dispersion to obtain an emulsion. Add the emulsion to a reaction vessel and stir. Add a pH adjuster and let stand for 24 hours to obtain a plant-derived fungicide.

2. The plant-derived fungicide according to claim 1, characterized in that, The pH adjuster in S3 is either a 0.05 mol / L citric acid aqueous solution or a 0.05 mol / L sodium hydroxide aqueous solution. The pH is adjusted to 6-7 by adding a pH adjuster.

3. The plant-derived fungicide according to claim 1, characterized in that, The emulsifier is a mixture of polyoxyethylene sorbitan monooleate and sorbitan fatty acid ester; The mass ratio of the polyoxyethylene sorbitan monooleate to the sorbitan fatty acid ester is 2:

1.

4. The plant-derived fungicide according to claim 3, characterized in that, The preparation of the modified allicin includes the following steps: A1. Add zinc chloride and deionized water to the reaction vessel and stir to obtain a zinc chloride solution; A2. Add allicin and the remaining deionized water to the reaction vessel and stir. Add zinc chloride solution and stir. Add citric acid aqueous solution and stir. Add chitosan powder and stir to obtain a mixture. Allow the mixture to cool naturally to 25°C. Place the mixture in a high-speed centrifuge and centrifuge. Collect the precipitate. Wash the precipitate with deionized water 2-3 times. After each wash, centrifuge for 5 minutes. Place the washed precipitate in a vacuum drying oven and dry to obtain modified allicin.

5. The plant-derived fungicide according to claim 4, characterized in that, Citric acid aqueous solution was added to A2 to adjust the pH to 4.5-5.5; The concentration of the citric acid aqueous solution is 0.05 mol / L.

6. The plant-derived fungicide according to claim 4, characterized in that, The mass ratio of zinc chloride to deionized water in A1 is 1:31.

25.

7. The plant-derived fungicide according to claim 4, characterized in that, The mass ratio of allicin, remaining deionized water, zinc chloride solution and chitosan powder in A2 is 5:12.5:12.6:

1.

8. The plant-derived fungicide according to claim 1, characterized in that, The preparation of the modified carvacrol includes the following steps: B1. Add carvacrol, glycerol and anhydrous ethanol to a reaction vessel and stir. Add urea powder and stir to obtain a carvacrol mixture. Add the carvacrol mixture to an ultrasonic disperser and disperse to obtain solution C. B2. Add β-cyclodextrin and deionized water to a reaction vessel and stir. Add solution C and stir. Add polyethylene glycol 400 and stir. Dry using a spray dryer to obtain modified carvacrol.

9. The plant-derived fungicide according to claim 8, characterized in that, The mass ratio of carvacrol, urea powder, glycerin, anhydrous ethanol, β-cyclodextrin, deionized water and polyethylene glycol 400 is 1:0.2:0.045:1.5:1.5:5:0.

045.

10. A plant-derived fungicide prepared by the method according to any one of claims 1-9 is suitable for preventing damping-off, seedling blight and root rot in strawberry seedlings, cucumber seedlings, tomato seedlings and flower seedlings.

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