Bactericidal agent as well as preparation method and application thereof

Abstract

The invention discloses a bactericidal agent as well as a preparation method and application thereof, and belongs to the field of pesticide preparation. The metalaxyl-M, the fluopyram and the metrafenone are compounded, a remarkable antibacterial effect is achieved, the antibacterial effect is not simple component superposition, a remarkable synergistic interaction effect is achieved in a reasonable proportion range, a remarkable prevention and treatment effect on damping-off of plants is achieved, the drug resistance of germs can be reduced, the cost is saved, and the bactericidal composition is worthy of popularization and application. And the safety to the environment is improved. In addition, the carrier is improved, so that the loading capacity is improved, and the utilization rate and the control effect of the bactericidal agent are further improved.

Description

Technical Field

[0001] The present invention relates to the field of pesticides, and in particular to a fungicide and a preparation method and application thereof. Background Art

[0002] Soil-borne diseases are one of the five most difficult plant diseases to prevent and control. They not only spread widely, but also cause serious harm. Chili pepper damping-off is one of the more serious soil-borne diseases in the process of pepper cultivation, especially in the seedling stage. The disease is caused by Fusarium fungi. In a humid environment, the mycelium grows faster, the infection speed is fast, and it can rely on running water to further accelerate the spread. It can also infect Solanaceae crops, such as eggplant, tomato and Cucurbitaceae crops such as cucumber. In addition, the mycelium of Fusarium fungi can also rely on diseased residues or humus in the soil to survive for a long time. When external conditions are ripe, they infect and cause disease, which is also one of the reasons why soil-borne diseases are difficult to prevent and control. Specifically, the onset of damping-off is mainly concentrated in the seedling stage, and there are three main symptoms: damping-off, seedling death and seed rot. In actual planting, the symptoms of damping-off and seedling death are the main ones. Among them, damping-off is that after the pepper seedlings emerge from the soil, the pathogen infects the seedlings before the true leaves unfold, and water-soaked spots appear at the base of the stems. The spots expand around the stems. As the disease progresses, the spots gradually shrink into thin lines, causing the pepper seedlings to lose support above the base of the stems and fall over. When the environmental humidity is high, a layer of white cotton-like hyphae will grow on the diseased plants or the diseased parts of the seedbed; dead seedlings are caused by the infection and death of the pepper seeds after the cotyledons are germinated and pulled out, but before they emerge from the soil. The main measure in the prior art is to prevent and control damping-off by drugs. For example, metalaxyl is used as a drug, and the probability of pepper damping-off is reduced by measures such as seed mixing, soil mixing, and spraying. Metalaxyl is a systemic fungicide with protective and therapeutic effects, which has the advantages of high fungicidal activity, low toxicity, high selectivity, and easy degradation. However, the use of a single metalaxyl flexible component has problems such as unsatisfactory prevention and control effects, increased drug resistance of pathogens, and large drug residues.

[0003] In addition, there are also biological control methods in the prior art, which specifically use the multiple action mechanisms of beneficial microorganisms on plant pathogens to weaken, kill, antagonize, and compete with pathogens. Although it has the advantages of being eco-friendly, safe for the human body, and alleviating the resistance of pathogens, biological control is still immature, there are many uncontrollable factors, and the pathogens are poorly targeted, and the control effect is slow.

[0004] Therefore, finding a suitable antibacterial composition and optimizing the process of the antibacterial composition to reduce drug resistance and improve antibacterial effect and antibacterial safety are the research directions of those skilled in the art. Summary of the invention

[0005] Based on this, in order to solve the technical problems of low antibacterial safety, bacterial resistance and poor antibacterial effect of the existing bactericidal agents, the present invention provides a bactericidal agent and a preparation method and application thereof. The specific technical scheme is as follows:

[0006] A bactericidal agent, comprising a composite antibacterial agent, an auxiliary agent and a carrier, wherein the carrier is used to load the composite antibacterial agent and the auxiliary agent;

[0007] Wherein, the mass ratio of the composite antibacterial agent, the auxiliary agent and the carrier is (1-15): (7-25): (20-50);

[0008] The composite antibacterial agent is composed of metalaxyl-M, fluopyram and metrafenone in a mass ratio of (6-13):(5-7):(1-7);

[0009] The carrier comprises modified clay-hollow mesoporous silica.

[0010] Furthermore, the preparation method of the carrier comprises the following steps:

[0011] Adding clay into a reaction kettle, adding sulfuric acid with a mass percentage concentration of 1% to 5%, treating under the first condition, and repeatedly washing and filtering to obtain pretreated clay;

[0012] Adding hollow mesoporous silica to the pretreated clay, adding a surfactant, treating under the second condition, centrifuging, washing and calcining to obtain clay-hollow mesoporous silica;

[0013] Cinnamic acid is added to ethanol to form a treating agent, and then clay-hollow mesoporous silica is added to the treating agent, mixed evenly, and then a silane coupling agent is added, and the mixture is treated under the third condition, and then filtered, washed and dried to obtain a carrier.

[0014] Furthermore, the first condition is: temperature of 45°C to 60°C, time of 20min to 25min, and ultrasound-assisted effect.

[0015] Furthermore, the mass ratio of the hollow mesoporous silica to the clay is (1-7):(1-3).

[0016] Furthermore, the second condition is: temperature of 60°C to 65°C, time of 20min to 25min, and stirring speed of 100r / min to 150r / min.

[0017] Furthermore, the calcination treatment is carried out at a temperature of 100° C. to 200° C. and for a time of 1 h to 2 h.

[0018] Furthermore, in the treatment agent, the mass percentage concentration of the cinnamic acid is 1% to 20%.

[0019] Furthermore, the third condition is: temperature of 45°C to 70°C, time of 20min to 30min, and stirring speed of 100r / min to 150r / min.

[0020] In addition, the present invention also provides a method for preparing a bactericidal agent, the preparation method comprising the following steps:

[0021] Metalaxyl-M, fluopyram and mefenamic acid are mixed, and the mixing temperature is controlled at 30°C to 40°C to obtain a composite antibacterial agent; then, an auxiliary agent and an appropriate amount of water are added while maintaining the temperature unchanged, and the mixture is mixed and treated at a speed of 50 r / min to 100 r / min for 20 min to 40 min; then, a carrier is added, and the mixture is treated at a condition of 30 r / min to 80 r / min for 40 min to 60 min to obtain a bactericidal agent.

[0022] The present invention also provides an application of a fungicide, which is an application of the fungicide in preventing and treating plant damping-off disease.

[0023] The above technical solution provides a bactericidal agent and its preparation method and application. Compared with the prior art, its beneficial effects include:

[0024] 1. The present invention compounds metalaxyl-M, fluopyram and metrafenone, and the activity and antibacterial effect are not simply the superposition of the components. Within a reasonable ratio range, they can play a significant synergistic role, not only having a significant preventive and control effect on plant damping-off disease, but also reducing the drug resistance of pathogens, saving costs and improving environmental safety.

[0025] 2. The present invention optimizes the process of the carrier, which helps to improve the loading effect of the carrier. Specifically, after the clay is treated with acid, the impurities in the clay can be reduced and the pore size of the clay can be increased, which helps to increase the specific surface area when it is combined with the hollow mesoporous silica. Then, cinnamic acid and a silane coupling agent are used for joint treatment to effectively modify the surface of the clay-hollow mesoporous silica, giving the carrier surface more double bonds and isomeric cinnamic acid, which not only effectively increases the loading effect, but also has an excellent sustained-release effect, thereby effectively improving the utilization rate and prevention and control effect of the bactericidal agent. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] A bactericidal agent in one embodiment of the present invention comprises a composite antibacterial agent, an auxiliary agent and a carrier, and the carrier is used to load the composite antibacterial agent and the auxiliary agent;

[0029] Wherein, the mass ratio of the composite antibacterial agent, the auxiliary agent and the carrier is (1-15): (7-25): (20-50);

[0030] The composite antibacterial agent is composed of metalaxyl-M, fluopyram and metrafenone in a mass ratio of (6-13):(5-7):(1-7);

[0031] The carrier comprises modified clay-hollow mesoporous silica.

[0032] In one embodiment, the method for preparing the carrier comprises the following steps:

[0033] Adding clay into a reaction kettle, adding sulfuric acid with a mass percentage concentration of 1% to 5%, treating under the first condition, and repeatedly washing and filtering to obtain pretreated clay;

[0034] Adding hollow mesoporous silica to the pretreated clay, adding a surfactant, treating under the second condition, centrifuging, washing and calcining to obtain clay-hollow mesoporous silica;

[0035] Cinnamic acid is added to ethanol to form a treating agent, and then clay-hollow mesoporous silica is added to the treating agent, mixed evenly, and then a silane coupling agent is added, and the mixture is treated under the third condition, and then filtered, washed and dried to obtain a carrier.

[0036] In one embodiment, the first condition is: temperature of 45°C to 60°C, time of 20min to 25min, and ultrasound-assisted effect.

[0037] In one of the embodiments, the mass ratio of the hollow mesoporous silica to the clay is (1-7): (1-3).

[0038] In one embodiment, the surfactant is at least one of sodium stearate and hexamethylenetetramine.

[0039] In one embodiment, the amount of the surfactant added is 10 to 15 times the volume.

[0040] In one embodiment, the second condition is: temperature of 60°C to 65°C, time of 20min to 25min, and stirring speed of 100r / min to 150r / min.

[0041] In one embodiment, the calcination treatment is carried out at a temperature of 100° C. to 200° C. and for a time of 1 h to 2 h.

[0042] In one of the embodiments, the mass percentage concentration of the cinnamic acid in the treatment agent is 1% to 20%.

[0043] In one embodiment, the added amount of the silane coupling agent accounts for 5% to 10% of the volume of the treating agent.

[0044] In one embodiment, the third condition is: temperature of 45°C to 70°C, time of 20min to 30min, and stirring speed of 100r / min to 150r / min.

[0045] In one embodiment, the present invention also provides a method for preparing a bactericidal agent, the preparation method comprising the following steps:

[0046] Metalaxyl-M, fluopyram and mefenamic acid are mixed, and the mixing temperature is controlled at 30°C to 40°C to obtain a composite antibacterial agent; then, an auxiliary agent and an appropriate amount of water are added while maintaining the temperature unchanged, and the mixture is mixed and treated at a speed of 50 r / min to 100 r / min for 20 min to 40 min; then, a carrier is added, and the mixture is treated at a condition of 30 r / min to 80 r / min for 40 min to 60 min to obtain a bactericidal agent.

[0047] In one embodiment, the auxiliary agent is at least one of a dispersant, a wetting agent, an emulsifier, a thickener, a stabilizer, a film former and a preservative.

[0048] In one embodiment, the dispersant is at least one of polycarboxylate and fatty acid polyoxyethylene ether sulfate.

[0049] In one embodiment, the wetting agent is at least one of sodium lauryl sulfate, alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

[0050] In one embodiment, the emulsifier is at least one of polyoxyethylene fatty acid ester and phenylphenol polyoxyethylene ether phosphate.

[0051] In one embodiment, the thickener is at least one of magnesium aluminum silicate, gum arabic and xanthan gum.

[0052] In one embodiment, the stabilizer is epoxidized soybean oil.

[0053] In one embodiment, the film-forming agent is polyvinyl alcohol.

[0054] In one embodiment, the preservative is at least one of potassium sorbate and sodium benzoate.

[0055] In one embodiment, the present invention further provides an application of a fungicide, wherein the application is the application of the fungicide in preventing and controlling plant damping-off disease.

[0056] In one embodiment, the plant is pepper.

[0057] In the above scheme, the components of the bactericidal agent interact with each other, synergize and enhance the effect, and have significant antibacterial properties and high safety.

[0058] The embodiments of the present invention will be described in detail below with reference to specific examples.

[0059] Embodiment 1:

[0060] A method for preparing a bactericidal agent comprises the following steps:

[0061] The clay was added into a reaction kettle, sulfuric acid with a mass percentage concentration of 3% was added, and ultrasonic-assisted treatment was performed at a temperature of 45° C. for 25 minutes. After repeated washing and suction filtration, the pretreated clay was obtained;

[0062] By weight, 5 parts of hollow mesoporous silica were added to 2 parts of the pretreated clay, 10 times the volume of sodium stearate was added, and the mixture was treated at a temperature of 60° C. and a stirring speed of 100 r / min for 25 min. After centrifugal filtration and washing, the mixture was calcined at a temperature of 120° C. for 2 h to obtain clay-hollow mesoporous silica;

[0063] Cinnamic acid is added to ethanol to form a treatment agent with a mass percentage concentration of cinnamic acid of 12%, and then clay-hollow mesoporous silica is added to the treatment agent, mixed evenly, and then a silane coupling agent accounting for 5% of the volume of the treatment agent is added, and the treatment is carried out at a temperature of 45° C. and a stirring speed of 100 r / min for 20 minutes, and the carrier is obtained by suction filtration, washing and drying;

[0064] Metalaxyl-M, fluopyram and mefenamic acid ketone in a mass ratio of 8:5:6 are mixed, and the mixing temperature is controlled at 30°C to obtain a composite antibacterial agent; then, while keeping the temperature unchanged, polycarboxylates, sodium lauryl sulfate, polyoxyethylene fatty acid esters, magnesium aluminum silicate, epoxy soybean oil, polyvinyl alcohol, potassium sorbate and an appropriate amount of water are added, and the mixture is mixed at a speed of 50 r / min for 25 minutes; then, a carrier is added, and the mixture is treated at 30 r / min for 45 minutes to obtain a bactericidal agent.

[0065] In Example 1, the mass ratio of the composite antibacterial agent, the auxiliary agent (2 parts of polycarboxylates, 7 parts of sodium lauryl sulfate, 8 parts of polyoxyethylene fatty acid esters, 1 part of magnesium aluminum silicate, 2 parts of epoxy soybean oil, 0.5 parts of polyvinyl alcohol, and 0.5 parts of potassium sorbate) and the carrier is 12:21:45.

[0066] Embodiment 2:

[0067] A method for preparing a bactericidal agent comprises the following steps:

[0068] The clay was added into a reaction kettle, sulfuric acid with a mass percentage concentration of 3% was added, and ultrasonic-assisted treatment was performed at a temperature of 45° C. for 25 minutes. After repeated washing and suction filtration, the pretreated clay was obtained;

[0069] Add 5 parts of hollow mesoporous silica to 3 parts of the pretreated clay by weight, add 10 times the volume of sodium stearate, treat at a temperature of 60°C and a stirring speed of 100r / min for 25min, centrifuge and wash, and calcine at a temperature of 150°C for 1h to obtain clay-hollow mesoporous silica;

[0070] Cinnamic acid is added to ethanol to form a treatment agent with a mass percentage concentration of cinnamic acid of 15%, and then clay-hollow mesoporous silica is added to the treatment agent, mixed evenly, and then a silane coupling agent accounting for 5% of the volume of the treatment agent is added, and the treatment is carried out at a temperature of 50° C. and a stirring speed of 100 r / min for 25 minutes, and the carrier is obtained by suction filtration, washing and drying;

[0071] Metalaxyl-M, fluopyram and mefenamic acid ketone in a mass ratio of 8:6:5 are mixed, and the mixing temperature is controlled at 35°C to obtain a composite antibacterial agent; then, while keeping the temperature unchanged, polycarboxylates, sodium dodecyl sulfate, phenylphenol polyoxyethylene ether phosphate, magnesium aluminum silicate, epoxy soybean oil, polyvinyl alcohol, potassium sorbate and an appropriate amount of water are added, and the mixture is mixed and treated at a speed of 50 r / min for 30 minutes; then, a carrier is added, and the mixture is treated at 30 r / min for 50 minutes to obtain a bactericidal agent.

[0072] In Example 2, the mass ratio of the composite antibacterial agent, the auxiliary agent (3 parts of polycarboxylate, 7 parts of sodium lauryl sulfate, 7 parts of phenylphenol polyoxyethylene ether phosphate, 1 part of magnesium aluminum silicate, 2 parts of epoxy soybean oil, 0.5 parts of polyvinyl alcohol, 0.5 parts of potassium sorbate) and the carrier is 13:21:45.

[0073] Embodiment 3:

[0074] A method for preparing a bactericidal agent comprises the following steps:

[0075] The clay was added into a reaction kettle, sulfuric acid with a mass percentage concentration of 3% was added, and ultrasonic-assisted treatment was performed at a temperature of 45° C. for 25 minutes. After repeated washing and suction filtration, the pretreated clay was obtained;

[0076] 5 parts of hollow mesoporous silica were added to 3 parts of the pretreated clay by weight, sodium stearate was added, and the mixture was treated at a temperature of 65° C. and a stirring speed of 100 r / min for 20 min. After centrifugal filtration and washing, the mixture was calcined at a temperature of 125° C. for 2 h to obtain clay-hollow mesoporous silica;

[0077] Cinnamic acid is added to ethanol to form a treatment agent with a mass percentage concentration of cinnamic acid of 15%, and then clay-hollow mesoporous silica is added to the treatment agent, mixed evenly, and then a silane coupling agent accounting for 5% of the volume of the treatment agent is added, and the treatment is carried out at a temperature of 50° C. and a stirring speed of 100 r / min for 30 minutes, and the carrier is obtained by suction filtration, washing and drying;

[0078] Metalaxyl-M, fluopyram and mefenamic acid ketone in a mass ratio of 7:7:5 are mixed, and the mixing temperature is controlled at 35°C to obtain a composite antibacterial agent; then, while keeping the temperature unchanged, polycarboxylates, sodium lauryl sulfate, polyoxyethylene fatty acid esters, magnesium aluminum silicate, epoxy soybean oil, polyvinyl alcohol, sodium benzoate and an appropriate amount of water are added, and the mixture is mixed and treated at a speed of 50 r / min for 30 minutes; then, a carrier is added, and the mixture is treated at 30 r / min for 60 minutes to obtain a bactericidal agent.

[0079] In Example 3, the mass ratio of the composite antibacterial agent, the auxiliary agent (3 parts of polycarboxylates, 7 parts of sodium lauryl sulfate, 8 parts of polyoxyethylene fatty acid esters, 1 part of magnesium aluminum silicate, 2 parts of epoxy soybean oil, 0.5 parts of polyvinyl alcohol and 0.5 parts of sodium benzoate) and the carrier is 15:22:46.

[0080] Comparative Example 1:

[0081] The difference between Comparative Example 1 and Example 3 is that Comparative Example 1 uses a single metalaxyl-M, and the rest is the same as Example 3.

[0082] Comparative Example 2:

[0083] The difference between Comparative Example 2 and Example 3 is that Comparative Example 2 uses a single fluopyram, and the rest is the same as Example 3.

[0084] Comparative Example 3:

[0085] The difference between Comparative Example 3 and Example 3 is that Comparative Example 3 uses a single mefenamic acid, and the rest is the same as Example 3.

[0086] Comparative Example 4:

[0087] The difference between Comparative Example 4 and Example 3 is that the mass ratio of metalaxyl-M, fluopyram and metrafenone in Comparative Example 4 is 1:1:17, and the others are the same as Example 3.

[0088] Comparative Example 5:

[0089] The difference between Comparative Example 5 and Example 3 is that the mass ratio of metalaxyl-M, fluopyram and metrafenone in Comparative Example 5 is 1:17:1, and the others are the same as Example 3.

[0090] Comparative Example 6:

[0091] The difference between Comparative Example 6 and Example 3 is that the mass ratio of metalaxyl-M, fluopyram and metrafenone in Comparative Example 6 is 17:1:1, and the others are the same as Example 3.

[0092] Comparative Example 7:

[0093] The difference between Comparative Example 7 and Example 3 is that the composite antibacterial agent in Comparative Example 7 is metalaxyl-M and fluopyram in a mass ratio of 1:18, and the rest is the same as Example 3.

[0094] Comparative Example 8:

[0095] The difference between Comparative Example 8 and Example 3 is that the composite antibacterial agent in Comparative Example 8 is fluopyram and metrafenone in a mass ratio of 1:18, and the rest is the same as Example 3.

[0096] Comparative Example 9:

[0097] The difference between Comparative Example 9 and Example 3 is that the composite antibacterial agent in Comparative Example 9 is metalaxyl-M and mefenamic acid ketone in a mass ratio of 18:1, and the rest is the same as Example 3.

[0098] Comparative Example 10:

[0099] The difference between Comparative Example 10 and Example 3 is that in Comparative Example 10, no carrier is used, and the corresponding composite antibacterial agent, auxiliary agent and water are mixed to obtain a bactericidal agent, and the added amount of the components is the same as that in Example 3.

[0100] Comparative Example 11:

[0101] The difference between Comparative Example 11 and Example 3 is that the carrier in Comparative Example 11 uses ordinary hollow mesoporous silica instead of the modified clay-hollow mesoporous silica, and the rest is the same as Example 3.

[0102] Comparative Example 12:

[0103] The difference between Comparative Example 12 and Example 3 is that the carrier in Comparative Example 12 is not treated with cinnamic acid and silane coupling agent, and the rest is the same as Example 3.

[0104] 1. Using the indoor toxicity determination method (according to the Sun Yunpei method), the co-toxicity coefficient (CTC value) of various compound mixtures was determined through indoor toxicity determination, and the synergistic effect of the mixture was judged by the CTC value.

[0105] Actual toxicity index ATI = standard drug LD 50 / Mixed Agent LD 50 *100;

[0106] Toxicity index TTI = standard drug LD 50 / Test drug LD 50 *100;

[0107] Co-toxicity coefficient CTC = ATI / TTI*100.

[0108] Table 1: Indoor co-toxicity coefficient test results

[0109]

[0110] From the results of the indoor co-toxicity coefficient determination provided in Table 1, it can be clearly seen that the metalaxyl-M, fluopyram and mefenamic acid in the embodiments of the present invention have a more excellent synergistic effect.

[0111] 2. Antibacterial test:

[0112] The test subjects were selected from plants infected with pepper damping-off disease. After shake flask culture, the fungicides in Examples 1 to 3 and Comparative Examples 10 to 12 were diluted 500 times with water, and then the same amount of the diluted fungicides were sprayed at the same time every day for antibacterial test. The antibacterial rates were shown in Table 2 below.

[0113] Table 2: Antibacterial rate results

[0114]

[0115] As can be seen from Table 2, the bactericidal agent loaded by the carrier of the present application exhibits a more excellent antibacterial effect. The difference between Comparative Examples 10 to 12 and Example 3 is that the carriers are different, which will affect the amount of active ingredients of the loaded bactericidal agent, and thus affect the antibacterial effect. This shows that the present application not only optimizes the active ingredients of the bactericidal agent, but also optimizes the structure of the carrier and the preparation process of the carrier, so that it has a more excellent antibacterial effect as a whole, and the sustained-release effect has a longer and more stable antibacterial effect.

[0116] 3. Field trials:

[0117] Test object: pepper damping-off disease

[0118] For pepper seedlings 15 days after emergence, the fungicides of Examples 1 to 3 and the fungicides of Comparative Examples 1 to 12 were diluted to make the composite antibacterial agent account for 20% of the volume of the agent. Ten days after application, the control effect was statistically analyzed, and the results are shown in Table 3. Relative control effect (%) = [(control disease rate - treatment disease rate) / control disease rate] x 100.

[0119] Table 3: Control effect

[0120] Group Control effect% Example 1 100 Example 2 100 Example 3 100 Comparative Example 1 86.6 Comparative Example 2 91.2 Comparative Example 3 93.2 Comparative Example 4 93.5 Comparative Example 5 91.0 Comparative Example 6 92.6 Comparative Example 7 88.9 Comparative Example 8 86.4 Comparative Example 9 89.2 Comparative Example 10 99.6 Comparative Example 11 99.1 Comparative Example 12 99.4

[0121] From the data analysis of Table 3, it can be seen that the compounded fungicide of the present application has an excellent control effect on pepper damping-off disease.

[0122] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A bactericidal agent, characterized in that: The bactericidal agent comprises a composite antibacterial agent, an auxiliary agent and a carrier, and the carrier is used to load the composite antibacterial agent and the auxiliary agent; Wherein, the mass ratio of the composite antibacterial agent, the auxiliary agent and the carrier is (1-15): (7-25): (20-50); The composite antibacterial agent is composed of metalaxyl-M, fluopyram and metrafenone in a mass ratio of (6-13):(5-7):(1-7); The carrier comprises modified clay-hollow mesoporous silica.

2. The bactericidal agent according to claim 1, characterized in that: The preparation method of the carrier comprises the following steps: Adding clay into a reaction kettle, adding sulfuric acid with a mass percentage concentration of 1% to 5%, treating under the first condition, and repeatedly washing and filtering to obtain pretreated clay; Adding hollow mesoporous silica to the pretreated clay, adding a surfactant, treating under the second condition, centrifuging, washing and calcining to obtain clay-hollow mesoporous silica; Cinnamic acid is added to ethanol to form a treating agent, and then clay-hollow mesoporous silica is added to the treating agent, mixed evenly, and then a silane coupling agent is added, and the mixture is treated under the third condition, and then filtered, washed and dried to obtain a carrier.

3. The bactericidal agent according to claim 2, characterized in that: The first condition is: temperature of 45°C to 60°C, time of 20min to 25min, and ultrasound-assisted effect.

4. The bactericidal agent according to claim 2, characterized in that: The mass ratio of the hollow mesoporous silica to the clay is (1-7):(1-3).

5. The bactericidal agent according to claim 2, characterized in that: The second condition is: temperature of 60°C to 65°C, time of 20min to 25min, stirring speed of 100r / min to 150r / min.

6. The bactericidal agent according to claim 2, characterized in that: The calcination treatment is carried out at a temperature of 100° C. to 200° C. and for a time of 1 h to 2 h.

7. The bactericidal agent according to claim 2, characterized in that: In the treating agent, the mass percentage concentration of the cinnamic acid is 1% to 20%.

8. The bactericidal agent according to claim 2, characterized in that: The third condition is: temperature of 45°C to 70°C, time of 20min to 30min, stirring speed of 100r / min to 150r / min.

9. A method for preparing a bactericidal agent, characterized in that: The preparation method is used to prepare the bactericidal agent according to any one of claims 1 to 8, and the preparation method comprises the following steps: Metalaxyl-M, fluopyram and mefenamic acid are mixed, and the mixing temperature is controlled at 30°C to 40°C to obtain a composite antibacterial agent; then, an auxiliary agent and an appropriate amount of water are added while maintaining the temperature unchanged, and the mixture is mixed and treated at a speed of 50 r / min to 100 r / min for 20 min to 40 min; then, a carrier is added, and the mixture is treated at a condition of 30 r / min to 80 r / min for 40 min to 60 min to obtain a bactericidal agent.

10. An application of a bactericidal agent, characterized in that: The application is the application of the fungicide according to any one of claims 1 to 8 in preventing and treating plant damping-off disease.

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