A microbial inoculant for controlling common diseases of chili peppers, its preparation method and application

Abstract

This invention discloses a microbial agent for controlling common diseases of chili peppers, its preparation method, and its application, belonging to the field of microbial control technology. The microbial agent of this invention comprises the following raw materials in parts by weight: 70-75 parts of compound microbial inoculum, 0.05-0.08 parts of brown sugar, 0.8-1.2 parts of trehalose, 0.2-0.3 parts of surfactant, 1.8-2.5 parts of potassium sorbate, and deionized water to a total of 100 parts. The compound microbial inoculum includes *Klebsiella pneumoniae*, *Akzoobacterium tumefaciens*, and *Bacillus subtilis*. This invention uses *Klebsiella pneumoniae*, *Akzoobacterium tumefaciens*, and *Bacillus subtilis* to form a compound microbial inoculum. The three inoculums are mixed in a specific ratio to synergistically inhibit the growth of pathogens, showing good antagonistic effects against chili pepper wilt, white mold, and blight, with the best inhibitory effect against blight. This microbial agent significantly increases the number of fruits per chili pepper plant and the overall health of the plant. Furthermore, its components are safe and environmentally friendly, non-toxic to chili peppers, and effectively extend the storage period of chili peppers.

Description

Technical Field

[0001] This invention belongs to the field of microbial control technology, specifically relating to a microbial agent for controlling common diseases of chili peppers, its preparation method, and its application. Background Technology

[0002] Chili peppers (Capsicum annuum) are an important economic crop, rich in nutrients and popular with consumers. Besides their edible value, capsaicin and capsaicin have significant applications in medicine and industry. With the expansion of planting areas, pathogens are accumulating in the soil, leading to increasingly serious soil-borne diseases affecting chili peppers. Phytophthora blight, Fusarium wilt, and white mold are occurring nationwide, causing plant wilting and fruit rot. These diseases spread rapidly and are difficult to control, severely impacting the quality and yield of chili peppers.

[0003] Currently, chemical agents are mainly used to control pepper diseases. However, excessive use of these agents has led to increased pathogen resistance, pesticide residues, and environmental pollution. With the implementation of green plant protection strategies, biological control is playing an increasingly important role. Utilizing biocontrol agents to control pepper diseases is of great significance for improving yield and quality and promoting the sustainable development of the industry.

[0004] For example, Chinese Patent CN113234635A discloses a compound microbial agent for controlling damping-off of peppers. This invention relates to a compound microbial agent for controlling damping-off of peppers, wherein the agent contains *Streptomyces loucherii* ACCC19748, *Trichoderma longifolia* ACCC32522, and *Pseudomonas putida* ACCC BCBKL 0060. The compound microbial agent of this invention has excellent control effect on damping-off of peppers and effectively reduces the incidence of damping-off of peppers. For example, Chinese Patent CN107446836A discloses a production process for a compound microbial agent for controlling bacterial wilt of peppers. The microbial agent used in this invention includes *Bacillus mucilaginosus*, *Trichoderma harzianum*, and *Streptomyces flavus*, which combine three probiotics to antagonize the bacterial wilt pathogen.

[0005] However, most of the above-mentioned invention patents for the biological control of chili diseases focus on preventing and controlling only one disease, which is a single function and difficult to effectively promote and apply in agricultural production. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a microbial agent for the prevention and control of common diseases of chili peppers, effectively controlling chili pepper wilt, blight, and white mold, while also increasing the number of fruits per chili pepper plant and extending the storage period of chili peppers.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A microbial agent for preventing and controlling common diseases of chili peppers comprises the following raw materials in parts by weight: 70-75 parts of compound microbial inoculum, 0.05-0.08 parts of brown sugar, 0.8-1.2 parts of trehalose, 0.2-0.3 parts of surfactant, 1.8-2.5 parts of potassium sorbate, and deionized water to make up to 100 parts;

[0009] The aforementioned compound microbial solution includes Klebsiella pneumoniae, Akzobacterium tumefaciens, and Bacillus subtilis.

[0010] Furthermore, the *Klebsiella pneumoniae* was purchased from the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 1.15640 and original accession date of April 10, 2016; the *Hydrogentobacter akazo* was purchased from the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 1.12365 and original accession date of October 15, 2012; and the *Bacillus subtilis* was purchased from the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 1.14985 and original accession date of December 10, 2014.

[0011] Furthermore, the preparation method of the composite microbial inoculum is as follows:

[0012] (1) Bacillus subtilis was activated in nutrient gravy agar medium, and a single colony was picked and inoculated into nutrient gravy liquid medium and cultured at 30℃ and 220r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture at a rate of 5% into the nutrient gravy liquid medium in the fermenter, and incubate at 30℃ and 220 r / min until the viable count reaches 1×10 8 The culture was terminated after cfu / mL, and the Bacillus subtilis fermentation broth was obtained.

[0013] (2) After thawing, Klebsiella pneumoniae and A. tsao-ko were activated in LB solid medium, and single colonies were picked and inoculated into LB liquid medium. They were cultured at 30°C and 170 r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture into LB liquid medium in the fermenter at a volume of 5% and incubate at 30℃ and 170 r / min until the viable count reaches 1×10. 8 After the concentration of cfu / mL was increased, the culture was terminated, and fermentation broths of Klebsiella pneumoniae and Bacillus thuringiensis were obtained, respectively.

[0014] (3) The Bacillus subtilis fermentation broth in step (1) and the Klebsiella pneumoniae fermentation broth and A. ts. fermentation broth in step (2) are mixed in a volume ratio of (1-2):(1-3):1 to obtain a composite microbial broth.

[0015] Furthermore, the microbial agent for preventing and controlling common diseases of chili peppers is a liquid preparation.

[0016] Furthermore, the surfactant is Tween-20.

[0017] A method for preparing a microbial inoculant for controlling common diseases of chili peppers includes the following steps:

[0018] Klebsiella pneumoniae, A. ts., and Bacillus subtilis were cultured separately. The fermentation broths of the three strains were mixed in a certain proportion to obtain a compound microbial inoculum. Under stirring, brown sugar, trehalose, surfactant, potassium sorbate, and deionized water were added to the compound microbial inoculum in sequence. The mixture was stirred thoroughly until completely dissolved, the pH was adjusted to 7.0, and large particulate impurities were removed by filtration to obtain a homogeneous microbial inoculum.

[0019] This invention also provides the application of microbial agents for the prevention and control of common diseases of chili peppers.

[0020] Furthermore, the common diseases mentioned are pepper wilt, pepper white mold, and pepper blight.

[0021] All raw materials used in this invention are commercially available.

[0022] The Bacillus subtilis used in this invention can secrete a variety of antibiotics (such as lipopeptides and proteases) and enzymes, which are rich in metabolites that directly destroy the cell wall and membrane structure of pathogenic fungi and inhibit the growth of pathogenic fungi.

[0023] The Klebsiella pneumoniae used in this invention can directly inhibit the growth of pathogens and has a strong colonization ability, improving the rhizosphere ecological environment and promoting root growth and development, thereby indirectly improving the plant's resistance to diseases.

[0024] The Akzobacterium tumefaciens used in this invention can secrete antibiotics, which have a strong inhibitory effect on the growth of pathogenic microorganisms. In addition, it has the ability to colonize on the plant surface and compete for nutrients, thus crowding out pathogens.

[0025] The three bacteria work synergistically to induce plant systemic resistance and enhance the chili pepper's resistance to diseases.

[0026] Beneficial effects

[0027] This invention uses a composite microbial culture composed of Klebsiella heterotrophus, A. ts., and Bacillus subtilis. The three cultures are mixed in a specific ratio and contain multiple active ingredients that synergistically inhibit the growth of pathogens. This culture has a good antagonistic effect on wilt disease, white mold disease, and blight of pepper, with the best inhibitory effect on blight of pepper.

[0028] The microbial agent prepared in this invention is simple, low-cost, and easy to use. Small amounts can significantly improve the control effect, reduce the incidence of pepper wilt, pepper white mold, and pepper blight, solve the problems of low pepper yield and high disease incidence, increase the number of fruits per pepper plant and the health of the plant, and the ingredients are safe and environmentally friendly, non-toxic to pepper, and effectively extend the storage period of pepper. Attached Figure Description

[0029] Figure 1 This is an antagonistic diagram of the compound microbial inoculum solution against three bacteria in Example 3 of the present invention; Note: A is the antagonistic diagram of the pathogen of pepper blight, B is the antagonistic diagram of the pathogen of pepper white rot, and C is the antagonistic diagram of the pathogen of pepper wilt. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0031] Example 1

[0032] A microbial agent for preventing and controlling common diseases of chili peppers comprises the following raw materials in parts by weight: 70 parts of compound microbial inoculum, 0.05 parts of brown sugar, 0.8 parts of trehalose, 0.2 parts of surfactant, 1.8 parts of potassium sorbate, and deionized water to make up to 100 parts;

[0033] The aforementioned compound microbial solution includes Klebsiella pneumoniae, Akzobacterium tumefaciens, and Bacillus subtilis.

[0034] The Klebsiella pneumoniae specimen has the CGMCC No. 1.15640; the A. ts. marine bacillus has the CGMCC No. 1.12365; and the Bacillus subtilis has the CGMCC No. 1.14985.

[0035] The method for preparing the composite microbial inoculum solution is as follows:

[0036] (1) Bacillus subtilis was activated in nutrient gravy agar medium, and a single colony was picked and inoculated into nutrient gravy liquid medium and cultured at 30℃ and 220r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture at a rate of 5% into the nutrient gravy liquid medium in the fermenter, and incubate at 30℃ and 220 r / min until the viable count reaches 1×10 8 The culture was terminated after cfu / mL, and the Bacillus subtilis fermentation broth was obtained.

[0037] (2) After thawing, Klebsiella pneumoniae and A. tsao-ko were activated in LB solid medium, and single colonies were picked and inoculated into LB liquid medium. They were cultured at 30°C and 170 r / min until OD. 600=0.6 to obtain seed culture, and inoculate the seed culture into LB liquid medium in the fermenter at a volume of 5% and incubate at 30℃ and 170 r / min until the viable count reaches 1×10. 8 After the concentration of cfu / mL was increased, the culture was terminated, and fermentation broths of Klebsiella pneumoniae and Bacillus thuringiensis were obtained, respectively.

[0038] (3) The Bacillus subtilis fermentation broth in step (1) and the Klebsiella pneumoniae fermentation broth and A. ts. fermentation broth in step (2) are mixed in a volume ratio of 2:3:1 to obtain a composite microbial broth.

[0039] The microbial agent for preventing and controlling common diseases of chili peppers is a liquid preparation.

[0040] The surfactant mentioned is Tween-20.

[0041] A method for preparing a microbial inoculant for controlling common diseases of chili peppers includes the following steps:

[0042] Klebsiella pneumoniae, A. ts., and Bacillus subtilis were cultured separately. The fermentation broths of the three strains were mixed in a certain proportion to obtain a compound microbial inoculum. Under stirring, brown sugar, trehalose, surfactant, potassium sorbate, and deionized water were added to the compound microbial inoculum in sequence. The mixture was stirred thoroughly until completely dissolved, the pH was adjusted to 7.0, and large particulate impurities were removed by filtration to obtain a homogeneous microbial inoculum.

[0043] Example 2

[0044] A microbial agent for preventing and controlling common diseases of chili peppers comprises the following raw materials in parts by weight: 72 parts of compound microbial inoculum, 0.07 parts of brown sugar, 1.0 part of trehalose, 0.3 parts of surfactant, 2.2 parts of potassium sorbate, and deionized water to make up to 100 parts;

[0045] The aforementioned compound microbial solution includes Klebsiella pneumoniae, Akzobacterium tumefaciens, and Bacillus subtilis.

[0046] The Klebsiella pneumoniae specimen has the CGMCC No. 1.15640; the A. ts. marine bacillus has the CGMCC No. 1.12365; and the Bacillus subtilis has the CGMCC No. 1.14985.

[0047] The method for preparing the composite microbial inoculum solution is as follows:

[0048] (1) Bacillus subtilis was activated in nutrient gravy agar medium, and a single colony was picked and inoculated into nutrient gravy liquid medium and cultured at 30℃ and 220r / min until OD. 600=0.6 to obtain seed culture, and inoculate the seed culture at a rate of 5% into the nutrient gravy liquid medium in the fermenter, and incubate at 30℃ and 220 r / min until the viable count reaches 1×10 8 The culture was terminated after cfu / mL, and the Bacillus subtilis fermentation broth was obtained.

[0049] (2) After thawing, Klebsiella pneumoniae and A. tsao-ko were activated in LB solid medium, and single colonies were picked and inoculated into LB liquid medium. They were cultured at 30°C and 170 r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture into LB liquid medium in the fermenter at a volume of 5% and incubate at 30℃ and 170 r / min until the viable count reaches 1×10. 8 After the concentration of cfu / mL was increased, the culture was terminated, and fermentation broths of Klebsiella pneumoniae and Bacillus thuringiensis were obtained, respectively.

[0050] (3) The Bacillus subtilis fermentation broth in step (1) and the Klebsiella pneumoniae fermentation broth and A. 2kJ fermentation broth in step (2) are mixed in a volume ratio of 2:2:1 to obtain a composite microbial broth.

[0051] The microbial agent for preventing and controlling common diseases of chili peppers is a liquid preparation.

[0052] The surfactant mentioned is Tween-20.

[0053] A method for preparing a microbial inoculant for controlling common diseases of chili peppers includes the following steps:

[0054] Klebsiella pneumoniae, A. ts., and Bacillus subtilis were cultured separately. The fermentation broths of the three strains were mixed in a certain proportion to obtain a compound microbial inoculum. Under stirring, brown sugar, trehalose, surfactant, potassium sorbate, and deionized water were added to the compound microbial inoculum in sequence. The mixture was stirred thoroughly until completely dissolved, the pH was adjusted to 7.0, and large particulate impurities were removed by filtration to obtain a homogeneous microbial inoculum.

[0055] Example 3

[0056] A microbial agent for preventing and controlling common diseases of chili peppers comprises the following raw materials in parts by weight: 75 parts of compound microbial inoculum, 0.08 parts of brown sugar, 1.2 parts of trehalose, 0.3 parts of surfactant, 2.5 parts of potassium sorbate, and deionized water to make up to 100 parts.

[0057] The aforementioned compound microbial solution includes Klebsiella pneumoniae, Akzobacterium tumefaciens, and Bacillus subtilis.

[0058] The Klebsiella pneumoniae specimen has the CGMCC No. 1.15640; the A. ts. marine bacillus has the CGMCC No. 1.12365; and the Bacillus subtilis has the CGMCC No. 1.14985.

[0059] The method for preparing the composite microbial inoculum solution is as follows:

[0060] (1) Bacillus subtilis was activated in nutrient gravy agar medium, and a single colony was picked and inoculated into nutrient gravy liquid medium and cultured at 30℃ and 220r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture at a rate of 5% into the nutrient gravy liquid medium in the fermenter, and incubate at 30℃ and 220 r / min until the viable count reaches 1×10 8 The culture was terminated after cfu / mL, and the Bacillus subtilis fermentation broth was obtained.

[0061] (2) After thawing, Klebsiella pneumoniae and A. tsao-ko were activated in LB solid medium, and single colonies were picked and inoculated into LB liquid medium. They were cultured at 30°C and 170 r / min until OD. 600 =0.6 to obtain seed culture, and inoculate the seed culture into LB liquid medium in the fermenter at a volume of 5% and incubate at 30℃ and 170 r / min until the viable count reaches 1×10. 8 After the concentration of cfu / mL was increased, the culture was terminated, and fermentation broths of Klebsiella pneumoniae and Bacillus thuringiensis were obtained, respectively.

[0062] (3) The Bacillus subtilis fermentation broth in step (1) and the Klebsiella pneumoniae fermentation broth and A. ts. fermentation broth in step (2) are mixed in a volume ratio of 1:1:1 to obtain a composite microbial broth.

[0063] The microbial agent for preventing and controlling common diseases of chili peppers is a liquid preparation.

[0064] The surfactant mentioned is Tween-20.

[0065] A method for preparing a microbial inoculant for controlling common diseases of chili peppers includes the following steps:

[0066] Klebsiella pneumoniae, A. ts., and Bacillus subtilis were cultured separately. The fermentation broths of the three strains were mixed in a certain proportion to obtain a compound microbial inoculum. Under stirring, brown sugar, trehalose, surfactant, potassium sorbate, and deionized water were added to the compound microbial inoculum in sequence. The mixture was stirred thoroughly until completely dissolved, the pH was adjusted to 7.0, and large particulate impurities were removed by filtration to obtain a homogeneous microbial inoculum.

[0067] Comparative Example 1

[0068] Compared with Example 3, this comparative example is identical to Example 3 except that the volume ratio of Klebsiella heterotrophus fermentation broth and A. ts. fermentation broth is changed to 1:1.

[0069] Comparative Example 2

[0070] Compared with Example 3, this comparative example is identical to Example 3 except that the volume ratio of Klebsiella pneumoniae fermentation broth to Bacillus subtilis fermentation broth in the compound microbial culture solution is changed to 1:1.

[0071] Comparative Example 3

[0072] Compared with Example 3, this comparative example is identical to Example 3 except that the volume ratio of Akzo Bacillus thuringiensis fermentation broth to Bacillus subtilis fermentation broth in the compound microbial culture solution is changed to 1:1.

[0073] Comparative Example 4

[0074] Compared with Example 3, this comparative example uses only Klebsiella pneumoniae fermentation broth in the compound microbial culture, while the other raw materials and steps are the same as in Example 3.

[0075] Comparative Example 5

[0076] Compared with Example 3, this comparative example uses only Akzo Bacillus marineis fermentation broth in the compound microbial culture, while the other raw materials and steps are the same as in Example 3.

[0077] Comparative Example 6

[0078] Compared with Example 3, this comparative example uses only Bacillus subtilis fermentation broth in the compound microbial culture, while the other raw materials and steps are the same as in Example 3.

[0079] Performance testing

[0080] Test for ability to inhibit pathogens:

[0081] The antagonistic effects of microbial agents against *Fusarium wilt*, *Sclerotium oxysporum*, and *Phytophthora blight* pathogens of pepper were determined using the plate confrontation culture method. *Fusarium wilt*, *Sclerotium oxysporum*, and *Phytophthora blight* fungal cakes (5 mm in diameter) were inoculated in the center of petri dishes. 50 μL of the compound microbial inoculum solution of Example 3 of this invention was inoculated approximately 2.5 cm around the center of the fungus. Sterile LB broth plates were used as controls. Each treatment was repeated three times. The inoculated petri dishes were incubated at 30°C for 4-5 days. The inhibitory effects on each pathogen are shown in the table below. Figure 1 Note: A is the antagonistic diagram of the pathogen of pepper blight, B is the antagonistic diagram of the pathogen of pepper white rot, and C is the antagonistic diagram of the pathogen of pepper wilt.

[0082] Depend on Figure 1 It can be seen that the compound microbial solution of the present invention, composed of Klebsiella heterotrophus, A. ts. and Bacillus subtilis, has a significant inhibitory effect on the pathogens of wilt, white mold, and blight of pepper.

[0083] Planting control effect trial

[0084] White sclerotium disease control experiment:

[0085] The experiment set up 10 treatment groups: blank control (sterile LB liquid medium), microbial inoculants of Examples 1-3 and Comparative Examples 1-6. Each treatment group treated 12 pepper seedlings, and the roots were drenched with 20 mL of sterile LB liquid medium, microbial inoculants prepared in Examples 1-3 and Comparative Examples 1-6, respectively. One week later, the base of the pepper roots was punctured, and neat blocks of Sclerotium sclerotiorum mycelium (d=8 mm) were inoculated at the wound. Disease incidence was recorded 5 days later.

[0086] Pepper white mold disease grading standards:

[0087] Level 0, asymptomatic;

[0088] Level 1, disease only occurs at the base of the stem;

[0089] Level 2, with the infected part accounting for less than 1 / 3 of the whole plant;

[0090] Level 3, with the infected part covering less than 2 / 3 of the entire plant;

[0091] Level 4: The plant is nearing or has already died.

[0092] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0093] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0094] Disease prevention and control experiment:

[0095] The experiment consisted of 10 treatment groups: a blank control (sterile LB liquid medium), and microbial inoculants prepared in Examples 1-3 and Comparative Examples 1-6. Each treatment group consisted of 12 pepper seedlings at the 4-5 leaf stage. The roots were drenched with 20 mL of sterile LB liquid medium, the microbial inoculants prepared in Examples 1-3, and the Comparative Examples 1-6, respectively. One week later, the base of the pepper roots was punctured, and 10 mL of 1×10⁻⁶ microbial inoculants was inoculated at the wound site. 5 CFU / mL Phytophthora capsici spore solution was used to record disease incidence after 15 days.

[0096] Pepper blight disease severity grading standards:

[0097] Level 0: No disease;

[0098] Grade 1: The seedlings show slight water-soaked brown discoloration at the root and stem base, and the leaves do not wilt or wilt reversibly;

[0099] Grade 2: The root and stem of the seedlings turn water-soaked brown, with the affected area being 1-2 cm in length. The leaves wilt irreversibly, and the lower leaves may occasionally fall off.

[0100] Grade 3: The root and stem of the seedlings turn water-soaked brown, the affected area is more than 2cm long, and the leaves are obviously wilted or fall off.

[0101] Grade 4: The root and stem of the seedling turn water-soaked brown, and the stems show signs of constriction. Except for the growing point, all leaves fall off or the plant wilts.

[0102] Level 5: Plant dies.

[0103] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0104] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0105] Fusarium wilt control experiment:

[0106] The experiment consisted of 10 treatment groups: a blank control (sterile LB liquid medium), and microbial inoculants prepared in Examples 1-3 and Comparative Examples 1-6. Each treatment group consisted of 12 pepper seedlings with 6 leaves and 1 bud. The roots were drenched with 20 mL of sterile LB liquid medium, the microbial inoculants prepared in Examples 1-3, and the Comparative Examples 1-6, respectively. One week later, the base of the pepper roots was punctured, and 10 mL of 1×10⁻⁶ microbial inoculants was inoculated at the wound site. 5 CFU / mL suspension of spores of Fusarium wilt in peppers was used to record disease incidence after 10 days.

[0107] Grading standards for Fusarium wilt in peppers:

[0108] Grade 0: Plants are growing normally;

[0109] Grade 1: The base of the plant stem turns brown and shrinks, the leaves are yellow and net-like, and nearly 1 / 4 of the leaves wilt from bottom to top. It has little impact on fruit production.

[0110] Grade 2: The base of the plant stem turns brown and shrinks, the leaves are yellow and net-like, nearly half of the leaves wilt from bottom to top, and the fruit grows slowly;

[0111] Grade 3: Nearly 3 / 4 of the leaves on the plant wilt from bottom to top, or one lateral branch wilts, yellowish-brown gelatinous substance flows from the stem, there are cracks, the melons are small and deformed, and they are dull.

[0112] Level 4: The entire plant wilts, does not bear fruit, or dies.

[0113] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0114] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0115] The results of the above-mentioned planting and disease control experiments are shown in Table 1.

[0116] Table 1. Control effects of each treatment group on each pathogen.

[0117]

[0118] As shown in Table 1, the microbial inoculants of this invention can effectively control Fusarium wilt, white mold, and Phytophthora blight in peppers, with control effects exceeding 70% against all three pathogens. Among them, the microbial inoculants of this invention showed the best control effect against Phytophthora blight in peppers. Meanwhile, comparative examples 1-6 with altered bacterial compositions were tested, and the synergistic balance of the three strains was disrupted, leading to a significant reduction in the disease resistance of peppers to varying degrees.

[0119] Planting trials and storage time determination

[0120] The field trial was conducted in a greenhouse. The pepper variety used was Lvyuan No. 3. The previous crop of peppers was mainly affected by Phytophthora blight, with mixed diseases such as Fusarium wilt also occurring, resulting in a total disease incidence rate of 45%. The trial consisted of 10 experimental groups: a blank control (water), Examples 1-3 and Comparative Examples 1-6, and microbial inoculants. The microbial inoculants for each treatment group were applied to the roots at a rate of 30 L / mu after being diluted 100 times. Each treatment group was replicated 3 times. Each plot was 4 meters long and 2 meters wide, with 1-meter-wide isolation rows between plots. The plots were raised, covered with mulch, and then the peppers were planted.

[0121] Sixty days after transplanting, select pepper plants with uniform growth and record the number of fruits. At 120 days, select 5 kg of intact peppers from each treatment group, pack them into plastic film preservation bags, and store them in a storage room at 5-8℃. The number of rotten fruits is recorded every 20 days, and the rotten fruits are removed. The above data are shown in Table 2.

[0122] Table 2 Results and Decay Rate During Storage

[0123]

[0124] As shown in Table 2, compared with the control group (CK), the application of the microbial inoculants of Examples 1-3 of this invention significantly increased the number of fruits per chili pepper plant and effectively extended the storage period of the chili peppers. No rotting occurred after 20 days of storage, and the rotting rate was also low after 60 days of storage. In contrast, Comparative Examples 1-6, which changed the composition of the microbial inoculant strains, showed a significantly higher rotting rate of chili peppers after 60 days of storage compared to the examples.

[0125] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A microbial inoculant for controlling common diseases of pepper, characterized by, The raw materials include the following components by weight: 70-75 parts of complex microbial bacteria liquid, 0.05-0.08 parts of brown sugar, 0.8-1.2 parts of trehalose, 0.2-0.3 parts of surfactant, 1.8-2.5 parts of potassium sorbate, and deionized water to make up 100 parts. The complex microbial bacteria liquid is composed of Klebsiella variicola, Oceanimonas aksiutica and Bacillus subtilis. The Klebsiella variicola has a preservation number of CGMCC No. 1.15640, the Oceanimonas aksiutica has a preservation number of CGMCC No. 1.12365, and the Bacillus subtilis has a preservation number of CGMCC No. 1.14985.

2. The microbial inoculant for controlling common diseases of pepper according to claim 1, characterized by, The preparation method of the complex microbial bacteria liquid is as follows: (1) Bacillus subtilis is activated in nutrient broth agar medium, single colony is picked and inoculated into nutrient broth liquid medium, and seed liquid is obtained by culturing at 30°C and 220 r / min until OD 600 =0.6; the seed liquid is inoculated into the nutrient broth liquid medium in the fermenter at an amount of 5%, and the culture is carried out at 30°C and 220 r / min until the viable cell count reaches 1×10 8 cfu / mL, and then the culture is terminated to obtain Bacillus subtilis fermentation liquid; (2) The Klebsiella variicola and Akkermansia aqus were respectively activated in LB solid medium after being thawed, and single colonies were respectively inoculated into LB liquid medium, and then cultured at 30°C and 170 r / min until OD 600 =0.6 to obtain seed liquid, and then the seed liquid was inoculated into LB liquid medium in the fermenter at an amount of 5%, and then cultured at 30°C and 170 r / min, and then the culture was ended after detecting that the viable cell count reached 1×10 8 cfu / mL, and then Klebsiella variicola fermentation liquid and Akkermansia aqus fermentation liquid were respectively obtained. (3) mixing the Bacillus subtilis fermentation liquid in step (1) and the Klebsiella variicola fermentation liquid and the Oceanimonas aksiutica fermentation liquid in step (2) according to a volume ratio of (1-2):(1-3):1 to obtain the complex microbial bacteria liquid.

3. The microbial inoculant for controlling common diseases of pepper according to claim 1, characterized in that, The microbial bacteria agent for preventing and treating common diseases of peppers is a liquid preparation.

4. The microbial inoculum for controlling common diseases of pepper according to claim 1, characterized by, The surfactant is Tween-20.

5. A method for preparing the microbial agent for controlling common diseases of pepper according to any one of claims 1 to 4, characterized by, The method includes the following steps: Klebsiella variicola, Oceanimonas aksiutica and Bacillus subtilis are respectively expanded and cultured, and the fermentation liquids of the three strains are compounded in proportion to obtain a complex microbial bacteria liquid.

6. The use of the microbial inoculant of claim 1 in the prevention and treatment of common diseases of pepper, characterized in that, The common diseases are pepper wilt, pepper white sordid disease and pepper blight.

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