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CN-121970768-A - Bactericidal composition containing tetramycin and thixotrope, and preparation method and application thereof

CN121970768ACN 121970768 ACN121970768 ACN 121970768ACN-121970768-A

Abstract

The invention relates to the field of pesticide preparations, and discloses a sterilization composition containing tetramycin and thixotrope, and a preparation method and application thereof; the system consists of high molecular weight modified lignosulfonate and specific lignin phenol fragments with low polymerization degree, wherein the high molecular weight component forms a physical barrier on the surface of active component particles, so that the storage stability and the application safety of the preparation are improved, and the low polymerization degree component can be degraded by extracellular enzymes secreted by citrus canker bacteria to realize the targeted release of the active component at a focus. The composition provided by the invention effectively reduces the decomposition rate of active components and the hazard risk of crops, and simultaneously remarkably improves the field control effect on citrus canker. The composition provides a new choice with high efficiency, safety and targeting effect for chemical prevention and treatment of citrus canker.

Inventors

  • ZHANG HONG

Assignees

  • 浙江东风化工有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (10)

  1. 1. A bactericidal composition, which is characterized by comprising tetramycin and thixotrope which are active components and a double-structure composite lignin derivative system which is taken as a functional carrier; In the active components, the weight ratio of the tetramycin to the thixotrope is (1:1) - (1:30); The double-structure composite lignin derivative system consists of high molecular weight modified lignin sulfonate and specific lignin phenol fragments with low polymerization degree.
  2. 2. The bactericidal composition of claim 1, wherein the composition comprises, in weight percent: the total amount of active components is 15.0% -40.0%; the total amount of the double-structure composite lignin derivative system is 3.0% -15.0%; 1.0% -5.0% of wetting agent; 3.0% -8.0% of antifreezing agent; 0.1% -0.5% of thickener; The balance of water.
  3. 3. The bactericidal composition of claim 1, wherein in the dual structure complex lignin derivative system: the molecular weight of the high molecular weight modified lignosulfonate is 20,000-50,000 g/mol; The molecular weight of the specific lignin phenol fragment with low polymerization degree is 500-2,000 g/mol; The weight ratio of the high molecular weight modified lignosulfonate to the specific lignin phenol fragment with low polymerization degree is (5:1) - (20:1).
  4. 4. The bactericidal composition of claim 1, wherein the composition is formulated as an aqueous suspension having a final pH of 5.5 to 6.5.
  5. 5. The bactericidal composition of claim 1, wherein the composition is a water-based suspension, and wherein the solid particles have a particle size distribution D90 of 1 to 5 μm.
  6. 6. A method of preparing the bactericidal composition of any of claims 1-5, comprising the steps of: (a) Pre-dispersing active components tetramycin, thixotrope and a double-structure composite lignin derivative system in water to form slurry; (b) And (c) carrying out wet sanding on the slurry obtained in the step (a) until the D90 value of the particle size distribution of the solid particles is 1-5 mu m.
  7. 7. The method of claim 6, wherein the cavity temperature is controlled to 20-45 ℃ by a cooling system during the wet sanding of step (b).
  8. 8. The method of claim 6, further comprising the step of post-formulation after wet sanding, the step comprising adjusting the final pH of the composition to 5.5-6.5 using a pH adjuster.
  9. 9. Use of a bactericidal composition as claimed in any one of claims 1 to 5 for the preparation of a pesticide formulation for controlling citrus canker.
  10. 10. Use according to claim 9, wherein the fungicidal composition, after being applied to the surface of a citrus plant, is capable of targeted release of the active components tetramycin and thistle under the action of extracellular enzymes secreted by the citrus canker pathogen.

Description

Bactericidal composition containing tetramycin and thixotrope, and preparation method and application thereof Technical Field The invention relates to the technical field of pesticide preparations, in particular to a sterilization composition containing tetramycin and thixotrope, and a preparation method and application thereof. Background Citrus canker is a serious bacterial disease caused by the pathogenic variety of xanthomonas campestris citrus (Xanthomonas citri subsp. Citri), and constitutes a persistent threat to the global citrus industry. The disease can infect the leaves, branch tips and fruits of citrus, cause the leaves to fall early and the branch tips to die, form wood-bolting disease spots, seriously affect the appearance quality and commodity value of the fruits, and even cause yield loss. At present, chemical control is still one of the key measures to control the spread and spread of citrus canker, and copper-containing bactericides and antibiotic bactericides are two main application categories. Thiser is used as an organic copper bactericide, and can inhibit the activity of various enzymes in pathogens by releasing copper ions, and has the characteristics of broad spectrum and high efficiency. However, conventional copper formulations have a general technical problem in application, namely that when free copper ions accumulate excessively on the surface of crops, they are liable to cause phytotoxicity to tender tissues (such as young shoots and young fruits) of citrus, and appear to burn spots or grow to be inhibited, which limits the use concentration and frequency thereof in a critical growth period. At the same time, improper use of copper ions may also lead to an environmental build-up risk. Tetramycin is an agricultural antibiotic, has a unique action mechanism, achieves a bacteriostatic effect by interfering synthesis of germ protein, has no cross resistance with copper preparations, and has higher safety to crops. The tetramycin and the thixotrope are compounded, so that the sterilization spectrum can be expanded theoretically, the resistance generation can be delayed, and the synergistic effect can be realized. However, combining these two active ingredients with significant differences in chemical properties in the same formulation faces serious technical challenges. On the one hand, tetramycin is not stable enough in chemical structure under specific conditions (such as the presence of certain metal ions or unfavorable pH environment), and is easy to degrade, so that the drug effect is reduced. On the other hand, the direct contact of the thixotrope and tetramycin in the preparation can affect each other, so that the physical or chemical properties are unstable, and the problems of layering, caking and the like occur, thereby reducing the storage stability and the practical application effect of the product. Therefore, the development of a compound preparation which not only can fully exert the synergistic bactericidal activity of tetramycin and thixotrope, but also can overcome the instability and the hazard risk of storage and application of the tetramycin and the thixotrope is a technical problem to be solved in the current field of prevention and treatment of citrus canker. Disclosure of Invention The invention aims to solve the technical problem of providing a bactericidal composition, a preparation method and application thereof, wherein the bactericidal composition solves the stability problem of active components in the preparation storage and application process by introducing specific functional components and adopting a specific process on the basis of containing tetramycin and thixotrope, and constructs an active component release mechanism triggered by specific pathogens. In order to solve the technical problems, the invention provides the following technical scheme: the first aspect of the present invention provides a bactericidal composition. The composition comprises tetramycin and thixotrope serving as active components and a double-structure composite lignin derivative system serving as a functional carrier. In the active component, the weight ratio of the tetramycin to the thixotrope is 1:1 to 1:30. The dual-structure composite lignin derivative system consists of two components: high molecular weight modified lignin sulfonate; specific lignin phenol fragments of low degree of polymerization. The preparation method of the specific lignin phenol fragment with low polymerization degree comprises the following steps: (1) Dissolving alkali lignin in sodium hydroxide aqueous solution to prepare lignin solution with the concentration of 5-15 g/L; (2) Transferring the solution obtained in the step (1) into a reaction kettle, introducing oxygen under the stirring condition, keeping the pressure in the kettle at 0.5-1.5 MPa, and simultaneously raising the temperature to 80-140 ℃; (3) Reacting for 30-90 minutes under the conditions of the temperature and the pressure,