Bacillus subtilis wettable powder and preparation method thereof

Abstract

The invention relates to the field of biopesticide and microbial fertilizer, in particular to bacillus subtilis wettable powder and a preparation method thereof. The bacillus subtilis wettable powder is prepared from the following preparation raw materials in parts by mass: 40 to 45 parts of bacillus subtilis fermentation liquor, 25 to 28 parts of a bio-based carrier, 0.5 to 0.7 part of sodium carboxymethyl cellulose, 1 to 1.2 parts of amino-oligosaccharin, 3 to 5 parts of a composite surfactant, 0.8 to 1.2 parts of a spore germination agent, 1.5 to 2 parts of a protective agent, 0.2 to 0.3 part of an anti-freezing agent and 0.2 to 0.3 part of a synergist. After the bacillus subtilis wettable powder is applied to a paddy field, the spore germination speed is high, the germination rate is high, the bacillus subtilis wettable powder is free of toxic effects on people and livestock and convenient to use, the fertilizer efficiency and the rice disease control effect of the bacillus subtilis wettable powder can be obviously improved, the dosage of spores is reduced, and the cost is reduced. The adhesiveness and conductivity of the bacillus subtilis wettable powder on rice can be improved through the composite surfactant, so that the bacillus subtilis wettable powder can be better attached to leaf surfaces and stem surfaces of the rice, and the control effect of the bacillus subtilis wettable powder on the neck blast of the rice is improved.

Description

Technical Field

[0001] The present application relates to the field of biological pesticides and microbial fertilizers, and in particular to a Bacillus subtilis wettable powder and a preparation method thereof. Background Art

[0002] Bacillus subtilis is the most studied microorganism among biological pesticides and microbial fertilizers. It has broad-spectrum antibacterial activity and extremely strong stress resistance. Its vegetative cells can reproduce and colonize on the surface of fungal pathogen mycelium, effectively inhibiting the growth of pathogens. Therefore, it shows broad application prospects in controlling disease occurrence, promoting plant growth, and increasing crop yields.

[0003] Due to the compatibility of different Bacillus subtilis with wetting agents, dispersants and other additives, the adsorption of different types of Bacillus by the carrier is different. The existing Bacillus subtilis wettable powder cannot be efficiently adsorbed and attached to the leaves and stems of rice, resulting in poor control effect. Summary of the invention

[0004] The purpose of the present application is to provide a Bacillus subtilis wettable powder and a preparation method thereof in view of the deficiencies of the current technology. The preparation method of the Bacillus subtilis wettable powder of the present application has the advantages of simple preparation, low cost, energy saving and environmental protection, etc., and the obtained Bacillus subtilis wettable powder has a fast spore germination speed and a high germination rate after being applied to a rice field, has no toxic effect on humans and animals, is easy to use, can significantly improve its fertilizer efficiency and the effect of preventing and controlling rice diseases, reduces the amount of spores used, and reduces costs. The adhesion and conductivity of the Bacillus subtilis wettable powder on rice can be improved by a composite surfactant, so that the Bacillus subtilis wettable powder can better adhere to the leaf and stem surfaces of rice, and improve the control effect of the Bacillus subtilis wettable powder on rice panicle neck blast.

[0005] In a first aspect, the present application provides a Bacillus subtilis wettable powder, which adopts the following technical solution: A Bacillus subtilis wettable powder comprises the following raw materials, measured by weight: 40-45 parts of Bacillus subtilis fermentation liquid, 25-28 parts of a bio-based carrier, 0.5-0.7 parts of sodium carboxymethyl cellulose, 1-1.2 parts of amino oligosaccharides, 3-5 parts of a composite surfactant, 0.8-1.2 parts of a spore germination agent, 1.5-2 parts of a protective agent, 0.2-0.3 parts of an antifreeze agent, and 0.2-0.3 parts of a synergist.

[0006] By adopting the above technical scheme, Bacillus subtilis fermentation liquid: as an effective ingredient, has the function of preventing and treating rice diseases. Bio-based carrier: made by extrusion, kneading and granulation of bio-based polymer material chitosan and calcium carbonate carrier. While acting as a carrier, it can also provide some nutrients for Bacillus subtilis and rice crops to absorb. Sodium carboxymethyl cellulose: as a dispersant, it helps to evenly disperse the powder in water. Amino oligosaccharides: can inhibit the growth of some plant pathogens, affect the germination of fungal spores, induce the variation of hyphae morphology, change the biochemistry of spores, etc. It can stimulate genes in plants to produce substances with disease resistance, and has a cell activation effect, which helps the recovery of damaged plants, promotes root growth and seedling growth, enhances the stress resistance of crops, and promotes plant growth and development. Composite surfactant: can improve the adhesion and conductivity of Bacillus subtilis wettable powder on rice, so that Bacillus subtilis wettable powder can better adhere to the leaf and stem surfaces of rice, and improve the control effect of Bacillus subtilis wettable powder on rice panicle neck blast. Spore germination agent: helps Bacillus subtilis to germinate quickly on rice and improve the disease prevention effect. Protective agent: helps to maintain the activity of Bacillus subtilis and extend its service life. Antifreeze: helps to prevent the powder from freezing in a low temperature environment to ensure its normal use. Synergist: helps to improve the control effect of Bacillus subtilis wettable powder, reduce the amount of spores, and reduce costs. Through the synergistic effect of the above components, the Bacillus subtilis wettable powder of the present application has a fast spore germination speed and a high germination rate after being applied to the rice field, has no toxic effect on humans and animals, is easy to use, can significantly improve its fertilizer efficiency and the control effect on rice diseases, reduce the amount of spores, and reduce costs.

[0007] Preferably, the method for preparing the Bacillus subtilis fermentation broth comprises the following steps: S21, transferring the purchased Bacillus subtilis strain to the slant of the NA medium test tube, and placing it in an incubator at 28°C for 2-3 days; wherein the NA medium is: 10g of peptone, 3g of beef extract, 5g of sodium chloride, 1000mL of deionized water, pH 7.3, and 2% agar is added to the NA medium; the deposit registration number of the Bacillus subtilis strain is CGMCC No.11632; S22. Under sterile conditions, the cultured Bacillus subtilis strain SDBRM01 was placed in NB liquid culture medium, and cultured in a shaking incubator at 28° C. for 18-24 hours to obtain a seed solution; wherein the NB liquid culture medium comprises: 3 g beef extract, 10 g peptone, 5 g NaCl, 1000 mL deionized water, pH 7.3; S23, inoculating the seed liquid into a large amount of fermentation medium at a volume ratio of 4.5%, the culture temperature is 28°C, and the culture time is 44-48h; the components and weight ratios of the large amount of fermentation medium are: 3.0% soybean powder, 3.0% corn powder, 0.2% light calcium carbonate, 0.1% sodium chloride, and the rest is deionized water, pH 7.3; after the fermentation is completed, the spore content is detected to be more than 20 billion CFU / ml, and the fermentation can be terminated to use the Bacillus subtilis fermentation liquid.

[0008] Preferably, the method for preparing the bio-based carrier comprises the following steps: S31, according to the mass fractions, chitosan, citric acid, xanthan gum and white carbon black were added into an ultrafine grinder and mixed and crushed evenly to obtain chitosan mother powder; S32. According to the mass proportions, 100 parts of chitosan mother powder and 120 parts of light calcium carbonate are added into an ultrafine grinder for grinding and mixing, and 25 parts of purified water are added into an extrusion granulator for granulation to obtain a bio-based carrier with a particle size of 0.1-0.2 mm.

[0009] By adopting the above technical scheme, the bio-based carrier is used as a carrier of Bacillus subtilis: the bio-based carrier can absorb a large amount of Bacillus subtilis, so that it can better adhere to the rice leaf and stem surfaces during the application process, and improve the control effect of Bacillus subtilis wettable powder on rice panicle neck blast. Provide nutrients: the bio-based carrier is made of bio-based polymer materials chitosan and calcium carbonate carriers by extrusion, kneading and granulation. While acting as a carrier, it can also provide some nutrients for Bacillus subtilis and rice crops to absorb. Promote soil and rice absorption: a small amount of acid is added to the carrier, and chitosan is dissolved when it is spread in water, which is convenient for soil and rice to absorb. Good compatibility with Bacillus subtilis: the bio-based carrier is very compatible with Bacillus subtilis and can absorb a large amount of Bacillus subtilis. Energy saving and environmental protection: the bio-based carrier is made of bio-based polymer materials and has the advantages of energy saving and environmental protection. In summary, the bio-based carrier of the present application plays an important role in the preparation of Bacillus subtilis wettable powder, can improve the control effect of Bacillus subtilis wettable powder, reduce costs, and has the advantages of energy saving and environmental protection.

[0010] Preferably, the mass ratio of chitosan, citric acid, xanthan gum and white carbon black is 96:2:0.8:4.5.

[0011] Preferably, the composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a mass ratio of 5:4:4.

[0012] By adopting the above technical scheme, the composite surfactant mainly plays the role of improving the adhesion and conductivity in the Bacillus subtilis wettable powder. By improving the adhesion of the powder on the leaves and stems of rice, it ensures that the active ingredients can be distributed more evenly and stably, and the action time is prolonged, thereby improving the control effect. Alkylphenol polyoxyethylene ether OP-7: As a non-ionic surfactant, it has good emulsification, wetting and cleaning functions. Among the composite surfactants, OP-7 is mainly responsible for reducing surface tension, stabilizing the mixed system, and enhancing the spreadability of the powder on the rice surface. Sorbitan monooleate SPAN-80: This is a non-ionic surfactant with excellent emulsification and stabilization properties. Among the composite surfactants, SPAN-80 helps to improve the wetting ability of OP-7 and increase the affinity of the powder to the plant surface, thereby promoting the absorption and utilization of the active ingredients. Sodium dodecyl sulfate: As an anionic surfactant, its main function is to enhance the foaming and penetration of the composite surfactant, making it easier for the powder to pass through the wax layer on the surface of the plant, increasing the absorption rate, and complementing with the nonionic surfactant to balance the charge distribution of the system and maintain stability. These three ingredients work together to exert the following synergistic effects: through interaction, a composite layer structure is formed, which enhances the adhesion of the powder to the leaves and stems of rice. By improving the spreadability and penetration of the powder, the active ingredients can be more evenly distributed on the surface of rice and promote the migration of the active ingredients to the target site. The combination of nonionic and anionic surfactants helps to maintain the stability of the mixed system, reduce separation and precipitation, and ensure the efficacy for a long time. The combination of surfactants is also conducive to reducing the dosage and cost of use, while avoiding negative impacts on rice and the environment. In summary, the synergistic effect between alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in the composite surfactant not only improves the use effect of Bacillus subtilis wettable powder, but also ensures the stability and environmental safety of the product.

[0013] Preferably, the spore germination agent is prepared by mixing L-alanine, inosine and fructose in a mass ratio of 1:2:5.

[0014] Preferably, the protective agent is prepared by mixing ascorbic acid, lecithin and sodium alginate in a mass ratio of 2:3:5.

[0015] Preferably, the synergist is prepared by mixing secondary alkanol polyoxyethylene ether and castor oil polyoxyethylene ether in a mass ratio of 2:3.

[0016] By adopting the above technical scheme, the synergist is prepared by mixing secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether in a mass ratio of 2:3, and its main function is to improve the activity and stability of Bacillus subtilis wettable powder. Secondary alkyl alcohol polyoxyethylene ether has good wettability and permeability, which can improve the adhesion and conductivity of Bacillus subtilis wettable powder on rice, so that the agent can better adhere to the rice leaf and stem surfaces, and improve the prevention and control effect of the agent on rice neck blast. Castor oil polyoxyethylene ether has good emulsification and dispersibility, which can improve the dispersibility of Bacillus subtilis wettable powder in water, so that the agent can be more evenly distributed in the rice field, and improve the use effect of the agent. The synergistic effect between secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether is mainly reflected in the complementarity of the two. Secondary alkyl alcohol polyoxyethylene ether mainly provides wettability and permeability, while castor oil polyoxyethylene ether mainly provides emulsification and dispersibility. The mixed use of the two can not only improve the adhesion and conductivity of the agent, but also improve the dispersibility and emulsification of the agent, thereby comprehensively improving the use effect of Bacillus subtilis wettable powder.

[0017] Preferably, the antifreeze agent is ethylene glycol.

[0018] In a second aspect, the present application provides a method for preparing a Bacillus subtilis wettable powder, using the following technical solution: As a general technical concept, the present application also provides a method for preparing the above-mentioned Bacillus subtilis wettable powder, comprising the following steps: mixing Bacillus subtilis fermentation broth, bio-based carrier, sodium carboxymethyl cellulose, amino oligosaccharide, composite surfactant, spore germination agent, protective agent, antifreeze agent and synergist according to mass fractions, stirring evenly, and then crushing to 325 mesh to obtain Bacillus subtilis wettable powder.

[0019] In summary, the beneficial technical effects of this application are: 1. Simple preparation method: The preparation method of the Bacillus subtilis wettable powder of the present application has the advantages of simple preparation, low cost, energy saving and environmental protection, and is suitable for large-scale production.

[0020] 2. Good application effect: After the obtained Bacillus subtilis wettable powder is applied to the rice field, the spores germinate quickly and have a high germination rate. It is non-toxic to humans and animals and is easy to use.

[0021] 3. Improve fertilizer efficiency and disease prevention effects: It can significantly improve fertilizer efficiency and rice disease prevention and control effects, reduce the amount of spores used, and reduce costs.

[0022] 4. Improve adhesion and conductivity: The composite surfactant can improve the adhesion and conductivity of Bacillus subtilis wettable powder on rice, so that Bacillus subtilis wettable powder can better adhere to the leaf and stem surfaces of rice, thereby improving the control effect of Bacillus subtilis wettable powder on rice neck blast.

[0023] 5. Provide nutrients: The bio-based carrier is made of bio-based polymer material chitosan calcium carbonate carrier extruded, kneaded and granulated. While acting as a carrier, it can also provide some nutrients for Bacillus subtilis and rice crops to absorb.

[0024] 6. Enhanced disease prevention and quality improvement effects: Aminooligosaccharides can inhibit the growth of some plant pathogens, affect the germination of fungal spores, induce the variation of hyphae morphology, and change the biochemistry of spores. It can stimulate the genes in plants to produce chitinase, glucanase, phosphodiesterase and PR protein with disease resistance, and has a cell activation effect, which helps the recovery of damaged plants, promotes root growth and seedling growth, enhances the stress resistance of crops, and promotes plant growth and development. Combined with Bacillus subtilis, Enhance its disease prevention and quality improvement effects. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] In the following examples and preparation examples, 1 part means 100 g.

[0027] Preparation Example 1 Preparation of Bacillus subtilis fermentation broth The method for preparing Bacillus subtilis fermentation broth comprises the following steps: S21, transferring the purchased Bacillus subtilis strain to the slant of the NA medium test tube, and placing it in an incubator at 28°C for 3 days; wherein the NA medium is: 10g of peptone, 3g of beef extract, 5g of sodium chloride, 1000mL of deionized water, pH7.3, and 2% agar is added to the NA medium; the deposit registration number of the Bacillus subtilis strain is CGMCC No.11632; S22. Under sterile conditions, the cultured Bacillus subtilis strain SDBRM01 was placed in NB liquid culture medium, and cultured on a shaker at 28° C. for 22 h to obtain a seed solution; wherein the NB liquid culture medium comprises: 3 g beef extract, 10 g peptone, 5 g NaCl, 1000 mL deionized water, pH 7.3; S23, inoculating the seed liquid into a large amount of fermentation medium at a volume ratio of 4.5%, the culture temperature is 28°C, and the culture time is 46h; the components and weight ratios of the large amount of fermentation medium are: 3.0% soybean powder, 3.0% corn powder, 0.2% light calcium carbonate, 0.1% sodium chloride, and the rest is deionized water, pH 7.3; after the fermentation is completed, the spore content is detected to be 25 billion CFU / ml, and the fermentation can be terminated, and the Bacillus subtilis fermentation liquid can be used.

[0028] Preparation Example 2 Preparation of Bio-based Carrier The method for preparing a bio-based carrier comprises the following steps: S31, according to the mass parts, add 96 parts of chitosan, 2 parts of citric acid, 0.8 parts of xanthan gum and 4.5 parts of white carbon black into an ultrafine grinder, mix and grind evenly to obtain chitosan mother powder; S32. According to the mass proportions, 100 parts of chitosan mother powder and 120 parts of light calcium carbonate are added into an ultrafine grinder for grinding and mixing, and 25 parts of purified water are added into an extrusion granulator for granulation to obtain a bio-based carrier with a particle size of 0.1-0.2 mm.

[0029] Example 1 A Bacillus subtilis wettable powder comprises the following raw materials, measured by weight: 40 parts of Bacillus subtilis fermentation liquid, 25 parts of bio-based carrier, 0.5 parts of sodium carboxymethyl cellulose, 1 part of amino oligosaccharide, 3 parts of composite surfactant, 0.8 parts of spore germination agent, 1.5 parts of protective agent, 0.2 parts of ethylene glycol, and 0.2 parts of synergist, wherein the composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a weight ratio of 5:4:4, the spore germination agent is prepared by mixing L-alanine, inosine and fructose in a weight ratio of 1:2:5, the protective agent is prepared by mixing ascorbic acid, lecithin and sodium alginate in a weight ratio of 2:3:5, and the synergist is prepared by mixing secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether in a weight ratio of 2:3; The preparation method of the above-mentioned Bacillus subtilis wettable powder comprises the following steps: according to the mass proportions, Bacillus subtilis fermentation liquid, bio-based carrier, sodium carboxymethyl cellulose, amino oligosaccharide, composite surfactant, spore germination agent, protective agent, ethylene glycol and synergist are mixed and stirred evenly, and then crushed to 325 meshes to obtain Bacillus subtilis wettable powder.

[0030] Example 2 A Bacillus subtilis wettable powder comprises the following raw materials, measured by weight: 45 parts of Bacillus subtilis fermentation liquid, 28 parts of bio-based carrier, 0.7 parts of sodium carboxymethyl cellulose, 1.2 parts of amino oligosaccharide, 5 parts of composite surfactant, 1.2 parts of spore germination agent, 2 parts of protective agent, 0.3 parts of ethylene glycol, and 0.3 parts of synergist, wherein the composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a weight ratio of 5:4:4, the spore germination agent is prepared by mixing L-alanine, inosine and fructose in a weight ratio of 1:2:5, the protective agent is prepared by mixing ascorbic acid, lecithin and sodium alginate in a weight ratio of 2:3:5, and the synergist is prepared by mixing secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether in a weight ratio of 2:3; The preparation method of the above-mentioned Bacillus subtilis wettable powder comprises the following steps: according to the mass proportions, Bacillus subtilis fermentation liquid, bio-based carrier, sodium carboxymethyl cellulose, amino oligosaccharide, composite surfactant, spore germination agent, protective agent, ethylene glycol and synergist are mixed and stirred evenly, and then crushed to 325 meshes to obtain Bacillus subtilis wettable powder.

[0031] Example 3 A Bacillus subtilis wettable powder comprises the following raw materials, measured by weight: 43 parts of Bacillus subtilis fermentation liquid, 27 parts of bio-based carrier, 0.6 parts of sodium carboxymethyl cellulose, 1.1 parts of amino oligosaccharide, 4 parts of composite surfactant, 1 part of spore germination agent, 1.8 parts of protective agent, 0.25 parts of ethylene glycol, and 0.25 parts of synergist, wherein the composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a weight ratio of 5:4:4, the spore germination agent is prepared by mixing L-alanine, inosine and fructose in a weight ratio of 1:2:5, the protective agent is prepared by mixing ascorbic acid, lecithin and sodium alginate in a weight ratio of 2:3:5, and the synergist is prepared by mixing secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether in a weight ratio of 2:3; The preparation method of the above-mentioned Bacillus subtilis wettable powder comprises the following steps: according to the mass proportions, Bacillus subtilis fermentation liquid, bio-based carrier, sodium carboxymethyl cellulose, amino oligosaccharide, composite surfactant, spore germination agent, protective agent, ethylene glycol and synergist are mixed and stirred evenly, and then crushed to 325 meshes to obtain Bacillus subtilis wettable powder.

[0032] Comparative Example 1 The same as Example 3, except that an equal amount of diatomaceous earth with a particle size of 0.1-0.2 mm is used instead of the bio-based carrier.

[0033] Comparative Example 2 The same as Example 3, except that the composite surfactant is alkylphenol polyoxyethylene ether OP-7.

[0034] Comparative Example 3 The same as Example 3, except that the composite surfactant is sorbitan monooleate SPAN-80.

[0035] Comparative Example 4 The same as Example 3, except that the composite surfactant is sodium dodecyl sulfate.

[0036] Comparative Example 5 The same as Example 3, except that the synergist is secondary alkanol polyoxyethylene ether.

[0037] Comparative Example 6 The same as Example 3, except that the synergist is castor oil polyoxyethylene ether.

[0038] Performance Testing 1. The Bacillus subtilis wettable powders prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were respectively subjected to field tests for controlling rice panicle blast. The test results are shown in Table 1.

[0039] The experimental site was selected in Tujiazhai Village, Tushi Town, with an altitude of 815m and a flat terrain. The experimental plots were relatively independent, with separate earth ridges in the plots. The soil fertility was consistent, the drainage and irrigation water were convenient and unobstructed, and the light conditions were good. There were 10 treatment areas in total, each with an area of ​​70m 2 , corresponding to Examples 1 to 3 and Comparative Examples 1 to 6 and clear water control, 667m 2 Use 30g of Bacillus subtilis wettable powder, dissolve it in 30L of water, and use a "Guardian WS-20P" backpack manual sprayer to spray the stems and leaves evenly. Application time and frequency: Bacillus subtilis wettable powder was applied twice on July 18 and July 28, and the clear water control was applied twice on July 18 and July 28. There was no rain 5 days after the application. Survey time and frequency: 1 survey at 14 days, 21 days after application, and 5 days before harvest; Field survey method for diseased ears of azoxystrobin: sampling at 5 points in each plot, 50 ears in each point, the specific standards are as follows: 0: no disease, 1: loss of less than 5% per ear (individual branches and stalks are diseased), 3: loss of 6%-20% per ear (about 1 / 3 of the branches and stalks are diseased), 5: loss of 21%-50% per ear (neck or main axis is diseased, grains are shriveled), 7: loss of 51%-70% per ear (neck is diseased, most of them are shriveled), 9: loss of 71%-100% per ear (neck is diseased, resulting in white ears); Calculation method of drug efficacy: 2. Product yield: On September 10, the experimental field measured 5m in each treatment area. 2 Output; test results are shown in Table 1.

[0040] Table 1 Control effect and yield Analyzing the data in Table 1, we can see that: 1) After the Bacillus subtilis wettable powder prepared in Examples 1 to 3 is applied to rice fields, its fertilizer efficiency and the effect of preventing and controlling rice diseases are significantly improved, the amount of spores used is reduced, and the cost is reduced. At the same time, the spores have a fast germination speed and a high germination rate, are non-toxic to humans and animals, and are easy to use.

[0041] 2) The performance comparison analysis of the Bacillus subtilis wettable powder prepared in Example 3 and Comparative Example 1 shows that the bio-based carrier prepared in the present application can adsorb a large amount of Bacillus subtilis, so that it can better adhere to the leaf and stem surfaces of rice during the application process, thereby improving the control effect of the Bacillus subtilis wettable powder on rice panicle blast, reducing costs, and having the advantages of energy saving and environmental protection.

[0042] 3) The performance comparison analysis of the Bacillus subtilis wettable powder prepared in combination with Example 3 and Comparative Examples 2-4 shows that the composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a mass ratio of 5:4:4, and the composite surfactant mainly plays a role in improving adhesion and conductivity in the Bacillus subtilis wettable powder. By improving the adhesion ability of the powder on the rice leaf surface and stem surface, it is ensured that the effective ingredients can be distributed more evenly and stably, and the action time is extended, thereby improving the control effect. By utilizing the synergistic effect between them, a composite layer structure is formed, which enhances the adhesion ability of the powder on the rice leaf surface and stem surface. By improving the spreadability and permeability of the powder, the effective ingredients can be more evenly distributed on the rice surface, and the migration of the effective ingredients to the target site is promoted. Not only the use effect of the Bacillus subtilis wettable powder is improved, but also the stability and environmental safety of the product are ensured.

[0043] 4) The performance comparison analysis of the Bacillus subtilis wettable powder prepared in combination with Example 3 and Comparative Examples 5-6 shows that the synergist is prepared by mixing secondary alkyl alcohol polyoxyethylene ether and castor oil polyoxyethylene ether in a mass ratio of 2:3. The synergistic effect between them can not only improve the adhesion and conductivity of the agent, but also improve the dispersibility and emulsification of the agent, thereby comprehensively improving the use effect of the Bacillus subtilis wettable powder.

[0044] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. A Bacillus subtilis wettable powder, characterized in that: The preparation raw materials include the following by weight: 40-45 parts of Bacillus subtilis fermentation broth, 25-28 parts of bio-based carrier, 0.5-0.7 parts of sodium carboxymethyl cellulose, 1-1.2 parts of amino oligosaccharides, 3-5 parts of complex surfactants, 0.8-1.2 parts of spore germination agents, 1.5-2 parts of protective agents, 0.2-0.3 parts of antifreeze agents, and 0.2-0.3 parts of synergists.

2. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The method for preparing the Bacillus subtilis fermentation broth comprises the following steps: S21, transfer the purchased Bacillus subtilis strain to the slant of the NA medium test tube, and place it in an incubator at 28°C for 2-3 days; wherein the NA medium is: 10g of peptone, 3g of beef extract, 5g of sodium chloride, 1000mL of deionized water, pH 7.3, and 2% agar is added to the NA medium; the deposit registration number of the Bacillus subtilis strain is CGMCC No.11632; S22. Under sterile conditions, the cultured Bacillus subtilis strain SDBRM01 was placed in NB liquid culture medium, and cultured in a shaking incubator at 28° C. for 18-24 hours to obtain a seed solution; wherein the NB liquid culture medium comprises: 3 g beef extract, 10 g peptone, 5 g NaCl, 1000 mL deionized water, pH 7.3; S23, inoculating the seed liquid into a large amount of fermentation medium at a volume ratio of 4.5%, the culture temperature is 28°C, and the culture time is 44-48h; the components and weight ratios of the large amount of fermentation medium are: 3.0% soybean powder, 3.0% corn powder, 0.2% light calcium carbonate, 0.1% sodium chloride, and the rest is deionized water, pH 7.3; after the fermentation is completed, the spore content is detected to be more than 20 billion CFU / ml, and the fermentation can be terminated to use the Bacillus subtilis fermentation liquid.

3. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The method for preparing the bio-based carrier comprises the following steps: S31, according to the mass fractions, chitosan, citric acid, xanthan gum and white carbon black were added into an ultrafine grinder and mixed and crushed evenly to obtain chitosan mother powder; S32. According to the mass proportions, 100 parts of chitosan mother powder and 120 parts of light calcium carbonate are added into an ultrafine grinder for grinding and mixing, and 25 parts of purified water are added into an extrusion granulator for granulation to obtain a bio-based carrier with a particle size of 0.1-0.2 mm.

4. A Bacillus subtilis wettable powder according to claim 3, characterized in that: The mass ratio of the chitosan, citric acid, xanthan gum and white carbon black is 96:2:0.8:4.

5.

5. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The composite surfactant is prepared by mixing alkylphenol polyoxyethylene ether OP-7, sorbitan monooleate SPAN-80 and sodium dodecyl sulfate in a mass ratio of 5:4:

4.

6. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The spore germination agent is prepared by mixing L-alanine, inosine and fructose in a mass ratio of 1:2:

5.

7. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The protective agent is prepared by mixing ascorbic acid, lecithin and sodium alginate in a mass ratio of 2:3:

5.

8. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The synergist is prepared by mixing secondary alkanol polyoxyethylene ether and castor oil polyoxyethylene ether in a mass ratio of 2:

3.

9. A Bacillus subtilis wettable powder according to claim 1, characterized in that: The antifreeze agent is ethylene glycol.

10. A method for preparing a Bacillus subtilis wettable powder according to any one of claims 1 to 9, characterized in that: The following steps are involved: According to the weight proportions, the Bacillus subtilis fermentation liquid, the bio-based carrier, sodium carboxymethyl cellulose, amino oligosaccharide, the composite surfactant, the spore germination agent, the protective agent, the antifreeze agent and the synergist are mixed and stirred evenly, and then crushed into 325 meshes to obtain the Bacillus subtilis wettable powder.

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