Mutant strain of high virulence beaver and its preparation method

Abstract

The application discloses a high-toxicity Beauveria mutagenesis strain and a preparation method of a microbial agent thereof, and belongs to the technical field of microbial agent preparation, which comprises the following raw materials in parts by weight: Beauveria raw powder 15-35 parts, chitin 10-25 parts, polyglutamic acid 10-20 parts, oyster shell powder 10-20 parts, chitin inhibitor 0.05-5 parts, organic silicon surfactant 0.25-8 parts, adsorbent 0.1-5 parts, dispersant 0.1-5 parts, wetting agent 0.1-5 parts, tackifier 0.1-5 parts and water 45-70 parts. In the application, through the synergistic effect of the chitin inhibitor and Beauveria bassiana, the toxicity and the death speed of the microbial agent to lepidoptera pests and coleoptera pests are significantly enhanced, the insect population reduction rate can reach more than 92.3% 14 days after field application, the microbial agent shows excellent persistence and control stability, and compared with the preparation without chitin / polyglutamic acid or chitin inhibitor, the microbial agent has obvious advantages in spore germination, infection efficiency and environmental adaptability.

Description

Technical Field

[0001] This invention belongs to the field of microbial agent preparation technology, specifically a highly virulent Beauveria bassiana mutant strain and its microbial agent preparation method. Background Technology

[0002] Beauveria bassiana is a broad-spectrum entomopathogenic fungus belonging to the phylum Ascomycota, order Cordyceps, family Cordycepsaceae, and genus Beauveria. It can infect a variety of pests through conidia and has significant application value in pest control. As a biological pesticide, Beauveria bassiana formulations have advantages such as being environmentally friendly, less prone to developing resistance, and safe for non-target organisms, making them an important alternative to chemical pesticides. They are widely used in the control of agricultural, forestry, and sanitary pests. However, existing Beauveria bassiana formulations face several technical bottlenecks in practical applications, hindering their large-scale promotion and full realization of field efficacy.

[0003] Currently, commercially available Beauveria bassiana products are mainly wettable powders. These formulations generally suffer from poor dispersibility, easy sedimentation, low spore suspension rate, and long wetting time, resulting in insufficient application uniformity and low field utilization. Furthermore, traditional formulations struggle to maintain the activity of Beauveria bassiana spores, exhibit poor storage stability, and lack effective synergistic components. Their toxicity and lethality against Lepidoptera and Coleoptera pests are limited, and their field persistence is poor, failing to meet the demands of modern agriculture for efficient and long-lasting biological control. Therefore, developing a Beauveria bassiana inoculant that combines high toxicity, excellent physical properties, and good environmental adaptability has become a pressing technical challenge in the field of biopesticides. Summary of the Invention

[0004] The purpose of this invention is to provide a highly virulent Beauveria bassiana mutant strain and a method for preparing its inoculum, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a highly virulent Beauveria bassiana mutant strain and its inoculum preparation method, comprising the following raw materials in parts by weight: 15-35 parts Beauveria bassiana raw powder, 10-25 parts chitin, 10-20 parts polyglutamic acid, 10-20 parts oyster shell powder, 0.05-5 parts chitin inhibitor, 0.25-8 parts organosilicon surfactant, 0.1-5 parts adsorbent, 0.1-5 parts dispersant, 0.1-5 parts wetting agent, 0.1-5 parts thickener, and 45-70 parts water;

[0006] As a further preferred embodiment of this technical solution, the following raw materials are included in parts by weight: 25 parts of Beauveria bassiana raw powder, 17 parts of chitin, 15 parts of polyglutamic acid, 15 parts of oyster shell powder, 2 parts of chitin inhibitor, 4 parts of organosilicon surfactant, 2.5 parts of adsorbent, 2.5 parts of dispersant, 2.5 parts of wetting agent, 2.5 parts of thickener, and 60 parts of water.

[0007] As a further preferred embodiment of this technical solution, the following steps are included:

[0008] S1: Weigh out the Beauveria bassiana raw powder, chitin, polyglutamic acid, oyster shell powder, chitin inhibitor, organosilicon surfactant, adsorbent, dispersant, wetting agent, thickener and water according to the weight ratio, put them into the mixing tank, and stir and mix at a speed of 200-600 rpm for 30-60 minutes to obtain a preliminary mixture.

[0009] S2: The preliminary mixture is ground and dispersed by a colloid mill, and the grinding fineness is controlled to D90 ≤ 5μm. Then it is passed through a 200-400 mesh sieve to obtain a homogeneous suspension.

[0010] S3: The homogeneous suspension is filled and sealed under aseptic conditions to obtain Beauveria bassiana suspension agent;

[0011] As a further preferred embodiment of this technical solution: the Beauveria bassiana mutant strain is Beauveria bassiana BB-UV-SG01, which is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC No.23245. This strain was obtained by ultraviolet nitrosoguanidine combined mutagenesis, and its conidium yield is increased by more than 40% compared with the original strain.

[0012] As a further preferred embodiment of this technical solution: the chitin inhibitor is diflubenzuron or flufenoxuron, the organosilicon surfactant is ethoxylated trisiloxane, the adsorbent is silica or activated carbon, the dispersant is polycarboxylate or alkylnaphthalene sulfonate, the wetting agent is sodium dodecyl sulfate or BX splitting powder, and the thickener is xanthan gum or sodium carboxymethyl cellulose.

[0013] As a further preferred embodiment of this technical solution: the microbial agent is used to control lepidopteran pests or coleopteran pests, the lepidopteran pests including corn borer, cotton bollworm, diamondback moth, and the coleopteran pests including grubs and potato beetles.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] 1. In this invention, the synergistic effect of chitin inhibitor and Beauveria bassiana significantly enhances the toxicity and lethality against lepidopteran and coleopteran pests. The pest population reduction rate can still reach more than 92.3% 14 days after field application, showing excellent persistence and control stability. At the same time, compared with preparations that do not contain chitin / polyglutamic acid or chitin inhibitor, this fungal agent has obvious advantages in spore germination, infection efficiency and environmental adaptability.

[0016] 2. In this invention, Beauveria bassiana BB-UV-SG01 was obtained through ultraviolet nitrosoguanidine composite mutagenesis. Its conidium yield was increased by more than 40% compared with the original strain, which significantly improved the content of effective ingredients and production efficiency of the fungal agent. At the same time, chitin, polyglutamic acid and oyster shell powder were used as nutrient and functional carriers, and a suspension formulation was designed with organosilicon surfactants, dispersants, wetting agents and thickeners. This gave the formulation excellent physical properties such as high spore suspension rate, short wetting time, small fineness and good storage stability, which solved the problems of poor dispersibility, easy precipitation and difficulty in maintaining spore activity of traditional wettable powders. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a highly virulent Beauveria bassiana mutant strain and its preparation method. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1:

[0020] Please see Figure 1 As shown, the present invention provides a technical solution: a highly virulent Beauveria bassiana mutant strain and its inoculum preparation method, comprising the following raw materials in parts by weight: 15-35 parts of Beauveria bassiana raw powder, 10-25 parts of chitin, 10-20 parts of polyglutamic acid, 10-20 parts of oyster shell powder, 0.05-5 parts of chitin inhibitor, 0.25-8 parts of organosilicon surfactant, 0.1-5 parts of adsorbent, 0.1-5 parts of dispersant, 0.1-5 parts of wetting agent, 0.1-5 parts of thickener, and 45-70 parts of water.

[0021] Further: Includes the following raw materials by weight: 25 parts Beauveria bassiana raw powder, 17 parts chitin, 15 parts polyglutamic acid, 15 parts oyster shell powder, 2 parts chitin inhibitor, 4 parts organosilicon surfactant, 2.5 parts adsorbent, 2.5 parts dispersant, 2.5 parts wetting agent, 2.5 parts thickener, and 60 parts water.

[0022] Preparation method:

[0023] S1: Weigh each raw material according to the above ratio, put them into the mixing tank, and stir and mix at 400 rpm for 45 minutes to obtain a preliminary mixture;

[0024] S2: The preliminary mixture is ground and dispersed by a colloid mill, and the grinding fineness is controlled to D90 ≤ 5μm. Then it is passed through a 300-mesh sieve to obtain a homogeneous suspension.

[0025] S3: The homogenized suspension is filled and sealed under aseptic conditions to obtain Beauveria bassiana suspension agent.

[0026] Example 2 (Low-content formulation):

[0027] Raw material ratio:

[0028] 15 parts Beauveria bassiana raw powder, 10 parts chitin, 10 parts polyglutamic acid, 10 parts oyster shell powder, 0.05 parts chitin inhibitor, 0.25 parts organosilicon surfactant, 0.1 parts adsorbent, 0.1 parts dispersant, and 45 parts water;

[0029] The preparation method is the same as in Example 1, with a stirring speed of 200 rpm and a time of 30 minutes. After grinding, the mixture is passed through a 200-mesh sieve.

[0030] Example 3 (High Content Formula):

[0031] Raw material ratio:

[0032] 35 parts Beauveria bassiana raw powder, 25 parts chitin, 20 parts polyglutamic acid, 20 parts oyster shell powder, 5 parts chitin inhibitor, 8 parts organosilicon surfactant, 5 parts adsorbent, 5 parts dispersant, 5 parts wetting agent, 5 parts thickener, and 70 parts water.

[0033] The preparation method is the same as in Example 1, with a stirring speed of 600 rpm and a time of 60 minutes. After grinding, the mixture is passed through a 400-mesh sieve.

[0034] Comparative example:

[0035] Comparative Example 1 (without chitin and polyglutamic acid);

[0036] Except for the absence of chitin and polyglutamic acid, the raw materials are the same as those in Example 1, with water added to make up the total number of parts; the preparation method is the same as in Example 1.

[0037] Comparative Example 2 (without chitin inhibitors);

[0038] Except for the absence of chitin inhibitors, the raw materials were the same as those in Example 1 in terms of composition and dosage, and the preparation method was the same as that in Example 1.

[0039] Comparative Example 3 (Conventional Beauveria bassiana wettable powder).

[0040] Commercially available Beauveria bassiana wettable powder (spore content 1×10¹) 0 (each 1 / g), dilute according to the instructions for use.

[0041] Effect verification

[0042] Formulation performance index table:

[0043]

[0044] The results showed that the suspension rate, wetting time, fineness and storage stability of Examples 1-3 were better than those of the comparative examples, with Example 1 showing the best results.

[0045] Field control effect

[0046] Background: During the cotton budding stage, spray with 200 mL of fungal agent per acre (diluted 500 times). Investigate the insect population reduction rate 7 days and 14 days after application.

[0047] The prevention effect is shown in the table below:

[0048]

[0049] The results showed that the field control efficacy of Example 1 reached 92.3% after 14 days, demonstrating good persistence and stability.

[0050] Conclusion: The above examples and comparative examples show that the suspension concentrate bacterial agent prepared using the formula described in this invention (containing Beauveria bassiana raw powder, chitin, polyglutamic acid, oyster shell powder, chitin inhibitor, organosilicon surfactant, adsorbent, dispersant, wetting agent, thickener and water) has the advantages of high spore suspension rate, fast wetting, small particle size and good storage stability. It shows excellent and long-lasting control effects on lepidopteran and coleopteran pests such as corn borer, cotton bollworm, and white grubs. It is significantly better than preparations without chitin / polyglutamic acid or chitin inhibitor, and also better than commercially available conventional Beauveria bassiana wettable powder.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A highly virulent Beauveria bassiana mutant strain and its inoculum preparation method, characterized in that: The ingredients include the following raw materials in parts by weight: 15-35 parts Beauveria bassiana raw powder, 10-25 parts chitin, 10-20 parts polyglutamic acid, 10-20 parts oyster shell powder, 0.05-5 parts chitin inhibitor, 0.25-8 parts organosilicon surfactant, 0.1-5 parts adsorbent, 0.1-5 parts dispersant, 0.1-5 parts wetting agent, 0.1-5 parts thickener, and 45-70 parts water.

2. The highly virulent Beauveria bassiana mutant strain and its inoculum preparation method according to claim 1, characterized in that: The ingredients include the following raw materials in parts by weight: 25 parts Beauveria bassiana powder, 17 parts chitin, 15 parts polyglutamic acid, 15 parts oyster shell powder, 2 parts chitin inhibitor, 4 parts organosilicon surfactant, 2.5 parts adsorbent, 2.5 parts dispersant, 2.5 parts wetting agent, 2.5 parts thickener, and 60 parts water.

3. The highly virulent Beauveria bassiana mutant strain and its inoculum preparation method according to claim 1, characterized in that: Includes the following steps: S1: Weigh out the Beauveria bassiana raw powder, chitin, polyglutamic acid, oyster shell powder, chitin inhibitor, organosilicon surfactant, adsorbent, dispersant, wetting agent, thickener and water according to the weight ratio, put them into the mixing tank, and stir and mix at a speed of 200-600 rpm for 30-60 minutes to obtain a preliminary mixture. S2: The preliminary mixture is ground and dispersed by a colloid mill, and the grinding fineness is controlled to D90 ≤ 5μm. Then it is passed through a 200-400 mesh sieve to obtain a homogeneous suspension. S3: The homogenized suspension is filled and sealed under aseptic conditions to obtain Beauveria bassiana suspension agent.

4. The highly virulent Beauveria bassiana mutant strain and its inoculum preparation method according to any one of claims 1, characterized in that: The Beauveria bassiana mutant strain is Beauveria bassiana BB-UV-SG01, which is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 23245. This strain was obtained by ultraviolet nitrosoguanidine combined mutagenesis, and its conidium yield was increased by more than 40% compared with the original strain.

5. The highly virulent Beauveria bassiana mutant strain and its inoculum preparation method according to claim 2, characterized in that: The chitin inhibitor is diflubenzuron or flufenoxuron, the organosilicon surfactant is ethoxylated trisiloxane, the adsorbent is silica or activated carbon, the dispersant is polycarboxylate or alkylnaphthalene sulfonate, the wetting agent is sodium dodecyl sulfate or BX (a type of thixotropic agent), and the thickener is xanthan gum or sodium carboxymethyl cellulose.

6. The highly virulent Beauveria bassiana mutant strain and its inoculum preparation method according to claim 1 or 2, characterized in that: The microbial agent is used to control lepidopteran or coleopteran pests, including corn borers, cotton bollworms, and diamondback moths, and grubs and potato beetles.

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