High-efficiency control agent for rice sheath blight disease based on biological agent

Abstract

The present invention relates to the technical field of pesticides, and discloses a biological agent-based rice sheath blight disease efficient control agent, which comprises an active flora, a carrier, an auxiliary agent and a disease resistance enhancing factor, the active flora is used for combining humidity, pH and temperature response type materials so as to make the bacterial agent dynamically released, and the disease resistance enhancing factor is used for controlling the disease resistance of the rice sheath blight disease. The carrier is used for enabling the active ingredients to be slowly released in a field environment and keep stability, the auxiliary additive is used for improving the activity, adhesiveness and soil adaptability of the fungicide, and the disease-resistant enhancing factor is used for expanding and improving the adaptability of the control agent. The ratio of the active flora to the carrier to the auxiliary additive to the disease-resistant enhancing factor is 10: 50: 13: 27. Through the synergistic effect of various functional strains and the combination of the dynamic release carrier, the occurrence and propagation of the rice sheath blight disease are effectively inhibited, the prevention and treatment rate can reach 75-85%, and the prevention and treatment effect is obviously higher than that of a traditional chemical pesticide or a single fungicide.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to a highly effective control agent for rice sheath blight based on a biological bacterial agent. Background Art

[0002] Rice sheath blight is a serious disease in rice production. It is caused by Rhizoctonia solani Kühn and is easily spread under high humidity conditions. It can cause the growth and development of rice to be hindered, ultimately seriously affecting the yield and quality.

[0003] High-efficiency control agents based on biological agents use microorganisms, such as bacteria, fungi, viruses or actinomycetes, as an alternative method to control crop diseases, insect pests and harmful microorganisms in the soil. These biological control agents can effectively inhibit or eliminate pathogens through various mechanisms, reduce the use of chemical pesticides, protect the ecological environment, and improve the sustainability of agricultural production.

[0004] In the prior art, synthetic pesticides are used for treatment. However, during use, it is uncertain whether the rice field is infected with rice sheath blight. For prevention purposes, the pesticides are used according to the field. As a result, some disease-free rice is exposed to pesticide residues, which leads to low rice yield and environmental pollution. At the same time, long-term use of pathogens can easily lead to drug resistance after long-term contact with a single chemical component, resulting in a decrease in the control effect of the drug. Chemical pesticides need to be applied multiple times for control, and the investment cost is relatively high. At the same time, there are potential risks to the safety of humans and animals during use. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a highly effective rice sheath blight control agent based on biological bacteria, which solves the problems that a single chemical component is prone to produce drug resistance, resulting in a decrease in the control effect of the agent, and excessive use of chemical pesticides leads to residual pollution, which not only affects the soil and water environment, but also has a negative impact on the crop ecosystem.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A highly effective control agent for rice sheath blight based on biological microbial agents, comprising:

[0008] Active bacteria, carriers, auxiliary additives and disease resistance enhancing factors;

[0009] The active bacterial flora is used to combine with humidity, pH and temperature responsive materials to enable dynamic release of the bacterial agent;

[0010] The carrier is used to allow the active ingredient to be slowly released and maintain stability in a field environment;

[0011] The auxiliary agent is used to improve the activity, adhesion and soil adaptability of the bacterial agent;

[0012] The disease resistance enhancement factor is used to expand and improve the adaptability of the control agent;

[0013] The ratio of the active bacteria, carrier, auxiliary agent and disease resistance enhancing factor is: 10 active bacteria: 50 carrier: 13 auxiliary agent: 27 disease resistance enhancing factor.

[0014] Preferably, the active bacterial community includes Trichoderma, Bacillus subtilis, Bacillus amyloliquefaciens and Pseudomonas, wherein the mass percentages of each material are 40-45% of Trichoderma, 25-30% of Bacillus subtilis, 15-20% of Bacillus amyloliquefaciens and 10-15% of Pseudomonas.

[0015] Preferably, the carrier comprises chitosan nanoparticles, sodium alginate-chitosan composite gel and thermosensitive hydrogel, wherein the mass percentages of the various materials are 40-50% chitosan nanoparticles, 25-35% sodium alginate-chitosan composite gel and 15-25% thermosensitive hydrogel.

[0016] Preferably, the auxiliary additives include adhesives, plant nutrient additives - seaweed extracts, organosilicon enhancers, protective agents and trace element supplements, wherein the mass percentages of each material are 35-45% adhesive, 20-30% plant nutrient additives - seaweed extracts, 10-20% organosilicon enhancers, 10-20% protective agents and 5-15% trace element supplements.

[0017] Preferably, the disease resistance enhancing factor comprises nano silicon oxide particles, plant-derived volatile organic compounds and iron carrier chelating agents, wherein the mass percentages of the respective materials are 50-60% of nano silicon oxide particles, 15-25% of plant-derived volatile organic compounds and 20-30% of iron carrier chelating agents.

[0018] A method for preparing a highly effective control agent for rice sheath blight based on a biological microbial agent comprises the following steps:

[0019] S1. Weigh the active bacteria according to the weight, then select the inoculated bacteria according to the different materials, and ferment them on a shaker to obtain a bacterial suspension, and then mix and stir the bacterial suspension to make it into powder to obtain the core functional powder;

[0020] S2, mixing the whole preparation, first pouring the prepared core functional powder into the carrier, stirring evenly, and then adding auxiliary additives and disease resistance enhancement factors to complete the whole mixing;

[0021] S3, drying and forming, the mixed whole preparation is dried by a spray dryer to form a uniform powder, and the powder is sieved.

[0022] Preferably, in S1, the configuration of the Trichoderma used is a medium containing 20 g glucose, 10 g peptone, 2 g KH2PO4, and 1 g MgSO4·7H2O per liter, and pH 6.0. The Trichoderma is inoculated and then fermented at 28-30°C and 100-120 rpm shaking for 4-5 days. After the bacterial liquid is collected, it is centrifuged at 4,000 rpm for 10 minutes to separate the bacterial cells to prepare a culture medium with a content of 2×10 8 CFU / mL of bacterial suspension;

[0023] Bacillus subtilis was inoculated with a medium containing 15 g glucose, 5 g yeast powder, 2 g K2HPO4, and 0.5 g MgSO4·7H2O per liter, and pH 7.0, and then cultured in a shaking incubator at 35-37°C and 120-150 rpm for 3-4 days. After centrifugation to separate the cells, the concentration was adjusted to 1.5×10 8 CFU / mL of bacterial suspension;

[0024] The preparation of Bacillus amyloliquefaciens is a medium containing 20 g soybean powder, 10 g starch, 3 g K2HPO4, and 1 g MgSO4·7H2O per liter, pH 6.8. Bacillus amyloliquefaciens is inoculated and then cultured in a shaking incubator at 28-30°C and 100-120 rpm for 3-4 days. The bacterial solution concentration is adjusted to 1×10 8 CFU / mL;

[0025] Pseudomonas was prepared by inoculating and culturing the culture medium containing 10 g glucose, 2 g potassium nitrate, 1 g KH2PO4, and 0.5 g MgSO4·7H2O per liter at pH 6.5, and then culturing the culture medium at 25-28°C and 180-200 rpm for 48 hours to prepare 0.5×10 8 CFU / mL of bacterial suspension.

[0026] Preferably, in S1, the bacterial suspension is mixed in a ratio of 35-40% of Trichoderma, 30-35% of Bacillus subtilis, 18-20% of Bacillus amyloliquefaciens and 10-12% of Pseudomonas, stirred evenly and freeze-dried to obtain a powder to obtain the functional powder.

[0027] Preferably, in S2, the carrier preparation includes preparing chitosan nanoparticles by dissolving 2% chitosan solution in 2% glacial acetic acid solution, stirring until completely dissolved, adding 1% sodium tripolyphosphate solution dropwise to the solution, and simultaneously ultrasonically emulsifying at an ultrasonic power of 180-200 W for 30-60 minutes to form chitosan nanoparticles, collecting by centrifugation, washing 3-4 times, and drying by a freeze dryer for later use;

[0028] Preparation of sodium alginate-chitosan composite gel: prepare 2% sodium alginate solution, stir evenly, add 1% chitosan solution into sodium alginate solution, stir to form composite gel, add 1% CaCl2 solution to crosslink for 30 minutes, let stand, wash and centrifuge to prepare gel particles;

[0029] Preparation of thermosensitive hydrogel: prepare 3% isopropyl acrylamide solution, add 0.5% crosslinking agent N,N'-methylenebisacrylamide and 0.1% initiator ammonium persulfate, stir in a 70°C water bath for 30 minutes to form thermosensitive hydrogel, and cut into particles after cooling for later use;

[0030] Finally, the chitosan nanospheres, sodium alginate-chitosan composite gel and thermosensitive hydrogel are mixed in a ratio of 25:15:10 and stirred evenly.

[0031] Preferably, in S3, the prepared core functional component powder is uniformly mixed into the carrier at a ratio of 10%, stirred until uniformly distributed, and the adhesive solution is added in sequence: 4.5%-5.5%, plant nutrient additive solution 2.5%-3.5%, organosilicon enhancer 1.5%-2.5%, protective agent 1.5%-2.5%, and stirred evenly after each additive is added;

[0032] Add disease resistance enhancement factors: add 14-16% nano silicon oxide particles, 4.5-5.5% plant source VOCs solution, and 6.5-7.5% iron carrier chelating agent solution in sequence, and stir until fully mixed. The drying temperature of the spray dryer is 50-60° C., and the particle size of the powder after sieving is 50-200 microns.

[0033] The present invention provides a highly effective control agent for rice sheath blight based on a biological microbial agent, which has the following beneficial effects:

[0034] 1. The present invention effectively inhibits the occurrence and spread of rice sheath blight through the synergistic effect of multiple functional strains combined with dynamic release carriers, with a control rate of 75%-85%, which is significantly higher than the control effect of traditional chemical pesticides or single bacterial agents.

[0035] 2. The present invention adopts a humidity, pH and temperature responsive composite carrier material to achieve the sustained release of the bacterial agent and extend the effective period in the field. Experimental results show that the effective period can reach more than 50 days, which significantly reduces the number of applications and reduces the cost of use.

[0036] 3. The present invention adopts natural flora and bio-based materials to avoid the pollution of chemical pesticides to the environment. At the same time, the powder preparation is stable in storage and easy to use, suitable for large-scale field promotion. It can achieve mass production during use while avoiding pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of a method for preparing a highly effective control agent for rice sheath blight based on a biological bacterial agent according to the present invention; DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Please see attached Figure 1 The embodiment of the present invention provides a highly effective control agent for rice sheath blight based on a biological microbial agent, comprising:

[0040] Active bacteria, carriers, auxiliary additives and disease resistance enhancing factors;

[0041] Active bacterial flora are used to combine with humidity, pH and temperature responsive materials to enable dynamic release of bacterial agents;

[0042] The carrier is used to allow the active ingredient to be released slowly and maintain stability in the field environment;

[0043] Auxiliary additives are used to improve the activity, adhesion and soil adaptability of bacterial agents;

[0044] Disease resistance enhancement factors are used to expand and improve the adaptability of control agents;

[0045] The ratio of active bacteria, carrier, auxiliary additives and disease resistance enhancing factors is: active bacteria 10: carrier 50: auxiliary additives 13: disease resistance enhancing factors 27.

[0046] The active bacterial flora comprises Trichoderma, Bacillus subtilis, Bacillus amyloliquefaciens and Pseudomonas, wherein the mass percentages of the various materials are 40-45% of Trichoderma, 25-30% of Bacillus subtilis, 15-20% of Bacillus amyloliquefaciens and 10-15% of Pseudomonas.

[0047] Specifically, based on the functional complementarity and synergy of each strain, a multiple prevention and control mechanism is formed to deal with rice sheath blight. Trichoderma directly degrades the cell wall of pathogens by secreting antibacterial substances such as chitinase and cellulase, and can also produce volatile organic compounds (VOCs) to further interfere with the growth and metabolism of pathogens. It also has a strong soil colonization ability, providing a stable foundation for subsequent prevention and control.

[0048] Bacillus subtilis is well-known for its ability to secrete antimicrobial peptides such as iturin, which can effectively inhibit the growth of Rhizoctonia solani. At the same time, it can weaken the pathogen's ability to obtain nutrients by competitively adsorbing iron ions, and can induce systemic resistance reactions in rice, thereby enhancing the rice's own disease resistance.

[0049] Bacillus amyloliquefaciens mainly regulates the rhizosphere microbial environment. Its metabolites can inhibit the spore germination of pathogens and promote the reproduction of healthy rhizosphere bacteria, thereby further optimizing the plant growth environment and improving rice disease resistance and root absorption capacity.

[0050] As an important supplementary strain, Pseudomonas plays an environmental adaptability and synergistic role in the bacterial community. It can inhibit the infection ability of pathogens by secreting siderophores, enzymes and secondary metabolites. At the same time, it promotes the metabolic processes of Bacillus subtilis and Trichoderma, enhances the disease resistance and adaptability of the overall bacterial community to the field environment, and significantly improves the comprehensive prevention and control effect of rice sheath blight through the synergistic effect of strains. At the same time, it ensures the long-term stability and effectiveness of the bacterial community in the field environment, which can effectively solve the problems of limited prevention and control effect and insufficient stability of a single strain, and provides a high-efficiency, green and sustainable effect for rice disease prevention and control.

[0051] The carrier comprises chitosan nano-microspheres, sodium alginate-chitosan composite gel and thermosensitive hydrogel, wherein the mass percentages of the various materials are 40-50% of chitosan nano-microspheres, 25-35% of sodium alginate-chitosan composite gel and 15-25% of thermosensitive hydrogel.

[0052] Specifically, chitosan nanospheres are used as the main component of the carrier. The biodegradability and biocompatibility of chitosan are utilized to prepare nanospheres with uniform particle size distribution, which can achieve responsive release through humidity changes, and gradually release the encapsulated active bacteria and their metabolites in the high humidity environment of the field to ensure the sustained effectiveness of the control agent. Chitosan itself has certain antibacterial properties, which further improves the control effect by acting on the cell wall of pathogens. The nanostructure of chitosan nanospheres provides a stable protective environment for the active bacteria, reducing the activity loss of the bacteria due to changes in the external environment during storage and transportation.

[0053] Sodium alginate-chitosan composite gel plays a role in fixing active ingredients in the carrier and enhancing field stability. Sodium alginate, as a natural polymer material, forms a composite gel with chitosan through Ca 2Cross-linking improves its mechanical strength and chemical stability, while giving it pH responsiveness. In field soil, when the metabolites of pathogens cause the pH value to decrease, the composite gel will gradually release the encapsulated active bacteria, thereby achieving precise release. The gel network structure of the composite gel helps the bacteria to adhere and colonize in the soil, providing a guarantee for the long-term function of the active bacteria.

[0054] The hydrogel is made of thermosensitive materials such as N-isopropylacrylamide, which can swell or shrink under high temperature conditions, thereby adjusting the release rate of active bacteria. This feature ensures the continuous release of the control agent during the critical period of rice growth (such as high temperature season) while avoiding waste of resources. The thermosensitive hydrogel also has excellent water retention properties and can provide suitable water support for active bacteria in the rhizosphere environment. The carrier can effectively protect the activity of the bacteria and extend the effective period of the control agent in the field, while avoiding the problems of bacterial inactivation or uneven release in traditional carriers.

[0055] Auxiliary additives include adhesives, plant nutrient additives - seaweed extracts, silicone enhancers, protective agents and trace element supplements, wherein the mass percentages of each material are 35-45% adhesive, 20-30% plant nutrient additives - seaweed extracts, 10-20% silicone enhancers, 10-20% protective agents and 5-15% trace element supplements.

[0056] Specifically, adhesives (such as polyvinyl alcohol) can improve the adhesion of bacterial agents on rice leaves and roots, prevent loss, and form a protective film to improve persistence; plant nutrient additives (such as seaweed extracts) provide nutrition for crops, promote bacterial colonization and induce plant resistance; organosilicon enhancers reduce the surface tension of bacterial agents, enhance spray coverage and permeability; protective agents (such as lactose, glycerol) improve the activity and stability of strains during storage and use; trace element supplements (such as zinc, boron, silicon) enhance rice resistance and support bacterial metabolism. The synergistic effect of the additives significantly improves the adhesion, stability and field control effects of the bacterial agents, and significantly enhances the efficiency and persistence of preventing and controlling rice sheath blight.

[0057] The disease resistance enhancing factor comprises nano silicon oxide particles, plant-derived volatile organic matter and iron carrier chelating agent, wherein the mass percentage of each material is 50-60% of nano silicon oxide particles, 15-25% of plant-derived volatile organic matter and 20-30% of iron carrier chelating agent.

[0058] Specifically, nano-silicon oxide particles have an ultra-high specific surface area and excellent adsorption properties, and can form a protective barrier on the leaf surface or rhizosphere of rice to prevent the invasion of pathogens such as Rhizoctonia solani. Nano-silicon oxide can indirectly enhance the disease resistance of rice by adjusting the soil microstructure and improving soil permeability, optimizing the root growth environment;

[0059] Plant-derived volatile organic compounds are important components that induce plant resistance through biological pathways. The present invention selects plant-derived VOCs (such as eugenol, pinene alcohol, etc.) with disease resistance effects. The main mechanism of action is to interfere with the metabolic activities and signal transduction of Rhizoctonia solani by releasing volatile compounds, while activating the systemic resistance (SR) of rice. VOCs can induce rice to express defense-related genes, thereby enhancing the defense ability of rice against pathogens. The volatility of VOCs enables it to cover a larger prevention and control range, and acts on pathogens in the field environment by gas phase diffusion, significantly reducing their infection ability.

[0060] Iron carrier chelators (such as EDTA iron or other organic matter that can chelate iron). Pathogens such as Rhizoctonia solani rely on iron ions as an important factor for metabolism and reproduction during the process of infecting rice. Iron carrier chelators can effectively chelate iron ions in the soil, weakening the ability of pathogens to utilize iron ions, thereby inhibiting their growth and reproduction. Chelators retain iron ions in an available form around the rhizosphere, which can be preferentially absorbed by the rice roots, meeting the crop's iron needs, thereby enhancing the plant's health and stress resistance.

[0061] A method for preparing a highly effective control agent for rice sheath blight based on a biological microbial agent comprises the following steps:

[0062] S1. Weigh the active bacteria according to the weight, then select the inoculated bacteria according to the different materials, and ferment them on a shaker to obtain a bacterial suspension, and then mix and stir the bacterial suspension to make it into powder to obtain the core functional powder;

[0063] S2, mixing the whole preparation, first pouring the prepared core functional powder into the carrier, stirring evenly, and then adding auxiliary additives and disease resistance enhancement factors to complete the whole mixing;

[0064] S3, drying and forming, the mixed whole preparation is dried by a spray dryer to form a uniform powder, and the powder is sieved.

[0065] In S1, the configuration of Trichoderma used was a medium containing 20 g glucose, 10 g peptone, 2 g KH2PO4, and 1 g MgSO4·7H2O per liter, with a pH of 6.0. Trichoderma was inoculated and then fermented at 28-30°C and 100-120 rpm shaking for 4-5 days. After the bacterial liquid was collected, it was centrifuged at 4,000 rpm for 10 minutes to separate the bacterial cells and prepare a medium with a content of 2×10 8 CFU / mL of bacterial suspension;

[0066] Bacillus subtilis was inoculated with a medium containing 15 g glucose, 5 g yeast powder, 2 g K2HPO4, and 0.5 g MgSO4·7H2O per liter, and pH 7.0, and then cultured in a shaking incubator at 35-37°C and 120-150 rpm for 3-4 days. After centrifugation to separate the cells, the concentration was adjusted to 1.5×10 8 CFU / mL of bacterial suspension;

[0067] The preparation of Bacillus amyloliquefaciens is a medium containing 20 g soybean powder, 10 g starch, 3 g K2HPO4, and 1 g MgSO4·7H2O per liter, pH 6.8. Bacillus amyloliquefaciens is inoculated and then cultured in a shaking incubator at 28-30°C and 100-120 rpm for 3-4 days. The bacterial solution concentration is adjusted to 1×10 8 CFU / mL;

[0068] Pseudomonas was prepared by inoculating and culturing the culture medium containing 10 g glucose, 2 g potassium nitrate, 1 g KH2PO4, and 0.5 g MgSO4·7H2O per liter at pH 6.5, and then culturing the culture medium at 25-28°C and 180-200 rpm for 48 hours to prepare 0.5×10 8 CFU / mL of bacterial suspension.

[0069] In S1, the bacterial suspension is mixed in a ratio of 35-40% of Trichoderma, 30-35% of Bacillus subtilis, 18-20% of Bacillus amyloliquefaciens and 10-12% of Pseudomonas, stirred evenly and freeze-dried to obtain a powder to obtain a functional powder.

[0070] Specifically, Trichoderma degrades the cell walls of pathogens by secreting chitinase and cellulase, and inhibits the growth of Rhizoctonia solani through competitive colonization. Bacillus subtilis secretes antimicrobial peptides (such as iturin) and siderophores, directly inhibiting the metabolism of pathogens and enhancing the systemic resistance of rice. Bacillus amyloliquefaciens improves the health of the root system by promoting the balance of rhizosphere microecology and inhibiting the germination of pathogen spores. Pseudomonas secretes secondary metabolites, further interfering with the reproduction and infection ability of pathogens. Freeze-drying technology converts the bacterial solution into powder form at low temperature, effectively avoiding thermal inactivation of the bacteria during handling and storage, and retaining the high activity of the bacterial flora.

[0071] In S2, carrier preparation includes preparation of chitosan nanoparticles: dissolving 2% chitosan solution in 2% glacial acetic acid solution, stirring until completely dissolved, adding 1% sodium tripolyphosphate solution dropwise to the solution, and simultaneously ultrasonically emulsifying at an ultrasonic power of 180-200W for 30-60 minutes to form chitosan nanoparticles, collecting by centrifugation, washing 3-4 times, and drying by a freeze dryer for later use;

[0072] Preparation of sodium alginate-chitosan composite gel: prepare 2% sodium alginate solution, stir evenly, add 1% chitosan solution into sodium alginate solution, stir to form composite gel, add 1% CaCl2 solution to crosslink for 30 minutes, let stand, wash and centrifuge to prepare gel particles;

[0073] Preparation of thermosensitive hydrogel: prepare 3% isopropyl acrylamide solution, add 0.5% crosslinking agent N,N'-methylenebisacrylamide and 0.1% initiator ammonium persulfate, stir in a 70°C water bath for 30 minutes to form thermosensitive hydrogel, and cut into particles after cooling for later use;

[0074] Finally, the chitosan nanospheres, sodium alginate-chitosan composite gel and thermosensitive hydrogel are mixed in a ratio of 25:15:10 and stirred evenly.

[0075] Specifically, chitosan nanospheres have humidity-responsive properties and can slowly release active bacteria in high-humidity environments in the field; sodium alginate-chitosan composite gel provides pH-responsive properties and releases bacteria in an acidic environment caused by pathogen metabolism; thermosensitive hydrogels adjust the release rate under high temperature conditions to adapt to field conditions in different seasons and growth periods;

[0076] All three carriers have good bacterial protection capabilities, avoiding the loss of activity of active bacteria during transportation, storage or complex field environments, and ensuring long-term prevention and control effects. The composite carrier can adapt to different rice planting environments, especially in field conditions with large changes in soil moisture and temperature fluctuations, effectively improving the effectiveness and resistance to environmental stress of the control agent. The composite carrier has excellent performance and can be used in combination with functional bacteria to significantly improve the prevention and control efficiency of rice sheath blight, achieving the goal of efficient, stable and sustainable disease prevention and control.

[0077] In S3, the prepared core functional component powder is uniformly mixed into the carrier at a ratio of 10%, stirred until evenly distributed, and the adhesive solution is added in sequence: 4.5%-5.5%, plant nutrient additive solution 2.5%-3.5%, organosilicon enhancer 1.5%-2.5%, protective agent 1.5%-2.5%, and stirred evenly after each additive is added;

[0078] Add disease resistance enhancing factors: add 14-16% nano silicon oxide particles, 4.5-5.5% plant-derived VOCs solution, and 6.5-7.5% iron carrier chelating agent solution in sequence, stir until fully mixed, the drying temperature of the spray dryer is 50-60°C, and the particle size of the powder after sieving is 50-200 microns.

[0079] Specifically, the synergistic effect of core functional ingredients, carriers, auxiliary adjuvants and disease resistance enhancing factors significantly improves the prevention and control efficiency of rice sheath blight, showing a disease control rate of 70%-85% in field experiments. The addition of plant-derived VOCs and siderophore chelators further induces rice systemic resistance, optimizes the rhizosphere microbial environment, and improves the overall health level of plants. Through the combination of humidity, temperature and pH responsive carriers with multifunctional adjuvants, the control agent shows stability and persistence under different field conditions. The powder form is convenient for uniform spraying or mixing into the soil, and the bacterial activity is stable for more than 12 months during storage. The preparation method is easy to operate, has high production efficiency, is suitable for large-scale industrial production, and meets the needs of green agriculture and sustainable development.

[0080] Embodiment 1:

[0081] Active bacteria: 10%, Trichoderma: 40%, Bacillus subtilis: 30%, Bacillus amyloliquefaciens: 20%, Pseudomonas: 10%, Carrier: 50%, Chitosan nanospheres: 45%, Sodium alginate-chitosan composite gel: 30%, Thermosensitive hydrogel: 25%, Auxiliary additives: 13%, Adhesive: 5%, Plant nutrient additives: 3%, Silicone enhancer: 2%, Protective agent: 3%, Disease resistance enhancement factor: 27%, Nano-silicon oxide particles: 15%, Plant-derived VOCs: 5%, Iron carrier chelator: 7%

[0082] Embodiment 2:

[0083] Active bacteria: 10%, Trichoderma: 38%, Bacillus subtilis: 32%, Bacillus amyloliquefaciens: 18%, Pseudomonas: 12%, Carrier: 50%, Chitosan nanospheres: 50%, Sodium alginate-chitosan composite gel: 30%, Thermosensitive hydrogel: 20%, Auxiliary additives: 13%, Adhesive: 4.5%, Plant nutrient additives: 2.5%, Silicone enhancer: 3%, Protective agent: 3.5%, Disease resistance enhancement factor: 27%, Nano-silicon oxide particles: 16%, Plant-derived VOCs: 5.5%, Iron carrier chelator: 5.5%

[0084] Comparative Example 1: Using the traditional chemical pesticide thiophanate-methyl at the recommended dosage

[0085] Comparative Example 2: Single bacterial agent treatment, using only Trichoderma (40%), without synergistic strains and vector design.

[0086] Table 1:

[0087]

[0088] From Table 1, we can see

[0089] In Example 1, the control rate reached 80%, and the effective period was as long as 50 days, showing the best control effect and field adaptability. In Example 2, the control rate was 75%, and the effective period was 45 days, which was slightly lower than that of the ratio 1, but still significantly better than the control group.

[0090] Compared with chemical pesticides, the control effects of Example 1 and Formula 2 were increased by 15% and 10% respectively, and the effective period was significantly extended. Although chemical pesticides have better short-term effects, their effective period is only 20 days, and repeated application is costly and may cause environmental pollution.

[0091] Comparison with a single bacterial agent: Compared with Example 1 and Formula 2, the control rate of the single bacterial agent increased by 35% and 30%, indicating the key role of strain synergy and dynamic release carrier, significantly improving the control effect and duration, and verifying its ability to effectively control rice sheath blight through dynamic release carriers and synergy of multiple strains, with a field control rate of 75%-85%.

[0092] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A highly effective control agent for rice sheath blight based on biological microbial agents, characterized in that: include: Active bacteria, carriers, auxiliary additives and disease resistance enhancing factors; The active bacterial flora is used to combine with humidity, pH and temperature responsive materials to enable dynamic release of the bacterial agent; The carrier is used to allow the active ingredient to be slowly released and maintain stability in a field environment; The auxiliary agent is used to improve the activity, adhesion and soil adaptability of the bacterial agent; The disease resistance enhancement factor is used to expand and improve the adaptability of the control agent; The ratio of the active bacteria, carrier, auxiliary agent and disease resistance enhancing factor is: 10 active bacteria: 50 carrier: 13 auxiliary agent: 27 disease resistance enhancing factor.

2. The highly effective control agent for rice sheath blight based on biological microbial agent according to claim 1, characterized in that: The active bacterial group comprises Trichoderma, Bacillus subtilis, Bacillus amyloliquefaciens and Pseudomonas, wherein the mass percentages of the various materials are 40-45% of Trichoderma, 25-30% of Bacillus subtilis, 15-20% of Bacillus amyloliquefaciens and 10-15% of Pseudomonas.

3. The highly effective control agent for rice sheath blight based on biological microbial agent according to claim 1, characterized in that: The carrier comprises chitosan nano-microspheres, sodium alginate-chitosan composite gel and thermosensitive hydrogel, wherein the mass percentages of the various materials are 40-50% of chitosan nano-microspheres, 25-35% of sodium alginate-chitosan composite gel and 15-25% of thermosensitive hydrogel.

4. The highly effective control agent for rice sheath blight based on biological microbial agent according to claim 1, characterized in that: The auxiliary additives include adhesives, plant nutrient additives-seaweed extracts, organosilicon enhancers, protective agents and trace element supplements, wherein the mass percentages of the various materials are respectively 35-45% of adhesives, 20-30% of plant nutrient additives-seaweed extracts, 10-20% of organosilicon enhancers, 10-20% of protective agents and 5-15% of trace element supplements.

5. The highly effective control agent for rice sheath blight based on biological microbial agent according to claim 1, characterized in that: The disease resistance enhancement factor comprises nano silicon oxide particles, plant-derived volatile organic matter and iron carrier chelating agent, wherein the mass percentage of each material is 50-60% of nano silicon oxide particles, 15-25% of plant-derived volatile organic matter and 20-30% of iron carrier chelating agent.

6. A method for preparing a highly effective control agent for rice sheath blight based on a biological microbial agent, applied to a highly effective control agent for rice sheath blight based on a biological microbial agent according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Weigh the active bacteria according to the weight, then select the inoculated bacteria according to the different materials, and ferment them on a shaker to obtain a bacterial suspension, and then mix and stir the bacterial suspension to make it into powder to obtain the core functional powder; S2, mixing the whole preparation, first pouring the prepared core functional powder into the carrier, stirring evenly, and then adding auxiliary additives and disease resistance enhancement factors to complete the whole mixing; S3, drying and forming, the mixed whole preparation is dried by a spray dryer to form a uniform powder, and the powder is sieved.

7. The method for preparing a highly effective control agent for rice sheath blight based on a biological agent according to claim 6, characterized in that: In S1, the configuration of Trichoderma used was a medium containing 20 g glucose, 10 g peptone, 2 g KH2PO4, and 1 g MgSO4·7H2O per liter, with a pH of 6.

0. Trichoderma was inoculated and then fermented at 28-30°C and 100-120 rpm shaking for 4-5 days. After the bacterial liquid was collected, it was centrifuged at 4,000 rpm for 10 minutes to separate the bacterial cells and prepare a medium with a content of 2×10 8 CFU / mL of bacterial suspension; Bacillus subtilis was inoculated with a medium containing 15 g glucose, 5 g yeast powder, 2 g K2HPO4, and 0.5 g MgSO4·7H2O per liter, and pH 7.0, and then cultured in a shaking incubator at 35-37°C and 120-150 rpm for 3-4 days. After centrifugation to separate the cells, the concentration was adjusted to 1.5×10 8 CFU / mL of bacterial suspension; The preparation of Bacillus amyloliquefaciens is a medium containing 20 g soybean powder, 10 g starch, 3 g K2HPO4, and 1 g MgSO4·7H2O per liter, pH 6.

8. Bacillus amyloliquefaciens is inoculated and then cultured in a shaking incubator at 28-30°C and 100-120 rpm for 3-4 days. The bacterial solution concentration is adjusted to 1×10 8 CFU / mL; Pseudomonas was prepared by inoculating and culturing the culture medium containing 10 g glucose, 2 g potassium nitrate, 1 g KH2PO4, and 0.5 g MgSO4·7H2O per liter at pH 6.5, and then culturing the culture medium at 25-28°C and 180-200 rpm for 48 hours to prepare 0.5×10 8 CFU / mL of bacterial suspension.

8. The method for preparing a highly effective control agent for rice sheath blight based on a biological agent according to claim 6, characterized in that: In S1, the bacterial suspension is mixed in a ratio of 35-40% of Trichoderma, 30-35% of Bacillus subtilis, 18-20% of Bacillus amyloliquefaciens and 10-12% of Pseudomonas, stirred evenly and freeze-dried to obtain a powder to obtain a functional powder.

9. The method for preparing a highly effective control agent for rice sheath blight based on a biological agent according to claim 6, characterized in that: In S2, carrier preparation includes preparation of chitosan nanoparticles: dissolving 2% chitosan solution in 2% glacial acetic acid solution, stirring until completely dissolved, adding 1% sodium tripolyphosphate solution dropwise to the solution, and simultaneously ultrasonically emulsifying at an ultrasonic power of 180-200W for 30-60 minutes to form chitosan nanoparticles, collecting by centrifugation, washing 3-4 times, and drying by a freeze dryer for later use; Preparation of sodium alginate-chitosan composite gel: prepare 2% sodium alginate solution, stir evenly, add 1% chitosan solution into sodium alginate solution, stir to form composite gel, add 1% CaCl2 solution to crosslink for 30 minutes, let stand, wash and centrifuge to prepare gel particles; Preparation of thermosensitive hydrogel: prepare 3% isopropyl acrylamide solution, add 0.5% crosslinking agent N,N'-methylenebisacrylamide and 0.1% initiator ammonium persulfate, stir in a 70°C water bath for 30 minutes to form thermosensitive hydrogel, and cut into particles after cooling for later use; Finally, the chitosan nanospheres, sodium alginate-chitosan composite gel and thermosensitive hydrogel are mixed in a ratio of 25:15:10 and stirred evenly.

10. The method for preparing a highly effective control agent for rice sheath blight based on biological microbial agents according to claim 6, characterized in that: In S3, the prepared core functional component powder is uniformly mixed into the carrier at a ratio of 10%, stirred until evenly distributed, and the adhesive solution is added in sequence: 4.5%-5.5%, plant nutrient additive solution 2.5%-3.5%, organosilicon enhancer 1.5%-2.5%, protective agent 1.5%-2.5%, and stirred evenly after each additive is added; Add disease resistance enhancement factors: add 14-16% nano silicon oxide particles, 4.5-5.5% plant source VOCs solution, and 6.5-7.5% iron carrier chelating agent solution in sequence, and stir until fully mixed. The drying temperature of the spray dryer is 50-60° C., and the particle size of the powder after sieving is 50-200 microns.

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