Microbial composition used for preventing and treating corn stem rot and having growth promoting function and application thereof

Abstract

The invention discloses a microbial composition used for preventing and treating corn stem rot and having a growth promoting function and application thereof, and relates to the technical field of biology. The invention relates to a microbial composition which is characterized by comprising paenibacillus peoriae (Paenibacillus peoriae) HFF-0-C5 and bacillus licheniformis (Bacillus licheniformis) HFF-0-C43, and the microbial composition is characterized in that the microbial composition comprises the paenibacillus peoriae (Paenibacillus peoriae) HFF-0-C5 and the bacillus licheniformis (Bacillus licheniformis) HFF-0-C43. The two strains are combined for use, so that the synergistic disease resistance can be generated, and the inhibition effect on the pathogenic fungus fusarium verticillioides of the corn stem rot can be effectively improved. The complex microbial inoculant prepared from the two strains provided by the invention can effectively enhance the soil fertility, improve the soil environment and induce plants to generate disease resistance, so that the comprehensive prevention and treatment effects of growth promotion and disease resistance are better achieved, and the quality improvement, yield increase and income increase of corn are realized. The complex microbial inoculant is safe, efficient, pollution-free and harmless to people and livestock, and has good application value.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to a microbial combination for preventing and controlling corn stalk rot and having a growth-promoting function and an application thereof. Background Art

[0002] So far, more than 100 corn diseases have been reported, causing yield losses of 10%-30% to corn. Corn stalk rot is one of the major diseases threatening corn production, and is gradually becoming more common. With climate change and increased planting density, the incidence of corn stalk rot has increased significantly, and the scope of the disease has continued to expand. In general years, the incidence rate is 15% to 20%, and in severe years it can reach more than 50% or even a total crop failure, causing inestimable losses to corn production and becoming one of the important factors limiting corn yields and income increases.

[0003] At present, with the long-term and large-scale use of chemical pesticides, various drawbacks have gradually been exposed. Therefore, it is urgent to explore and develop safe, efficient and environmentally friendly prevention and control methods.

[0004] As a substitute for chemical fertilizers and pesticides, microbial agents have become a research hotspot for many plant disease researchers in recent years. Biological control is green and environmentally friendly, pathogens are not easy to develop drug resistance, the production process of biocontrol agents is relatively simple, and they can promote crop growth, and have broad application prospects. Compared with a single biocontrol strain, a biocontrol bacterial community has a better disease prevention effect. The biocontrol preparations of a single bacterial community are subject to the constraints of different use environments and the influence of factors such as competition from environmental microorganisms, and the prevention and control effect is difficult to be stable. In addition, due to factors such as the production cost of the agent and the shelf life, the biocontrol effect is not as good as that of the biocontrol bacterial community. Combining strains with different biological functions can make up for the shortcomings of a single strain, screen out biocontrol agents with more significant prevention and control effects, and improve the biocontrol effect. Based on this, the present invention intends to develop a microbial combination for preventing and controlling corn stalk rot and having a growth-promoting function, so as to improve the biocontrol effect and increase corn yield at the same time. Summary of the invention

[0005] The purpose of the present invention is to provide a microbial combination and application thereof for preventing and controlling corn stalk rot and having a growth-promoting function, so as to solve the problems existing in the above-mentioned prior art. The present invention has found that the combination of Paenibacillus peoriae HFF-0-C5 and Bacillus licheniformis HFF-0-C43 with a potassium-solubilizing function can produce synergistic disease resistance, effectively improve the inhibitory effect on the pathogenic fungus of corn stalk rot, Fusarium pseudoverticillium, thereby achieving a comprehensive prevention and control effect of growth promotion and disease resistance.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a microbial combination for preventing and controlling corn stalk rot and having a growth-promoting function, comprising Paenibacillus peoriae HFF-0-C5 and Bacillus licheniformis HFF-0-C43;

[0008] The Paenibacillus piloriformis HFF-0-C5 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on October 23, 2023, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28717;

[0009] The Bacillus licheniformis HFF-0-C43 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on October 23, 2023. The deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28718.

[0010] Furthermore, the quantity ratio of the Bacillus pierrei HFF-0-C5 and the Bacillus licheniformis HFF-0-C43 is 2:(1-3).

[0011] Preferably, the quantitative ratio of the Bacillus pierrei HFF-0-C5 to the Bacillus licheniformis HFF-0-C43 is 1:1.

[0012] The present invention also provides the use of the above-mentioned microbial combination in preparing a composite bacterial agent with the functions of preventing and controlling corn stalk rot and promoting growth.

[0013] Furthermore, the composite bacterial agent is a liquid bacterial agent, a coating agent or a granule.

[0014] The present invention also provides a composite bacterial agent with the functions of preventing and controlling corn stalk rot and promoting growth, wherein the active ingredients include the above-mentioned microbial combination.

[0015] Furthermore, the composite bacterial agent also includes auxiliary materials.

[0016] Furthermore, the composite bacterial agent is in the form of a liquid bacterial agent, a coating agent or a granule.

[0017] Furthermore, when the dosage form of the composite bacterial agent is a liquid bacterial agent, the auxiliary materials are gum arabic powder, Tween 80 and tea polyphenols;

[0018] When the dosage form of the composite bacterial agent is a coating agent, the auxiliary material is a film-forming agent;

[0019] When the dosage form of the composite bacterial agent is granules, the auxiliary materials are kaolin and tyrosine.

[0020] The present invention also provides the use of the above-mentioned microbial combination or composite bacterial agent in preventing and controlling corn stalk rot and / or increasing corn yield.

[0021] The present invention discloses the following technical effects:

[0022] The present invention isolates Paenibacillus peoriae HFF-0-C5 with antagonistic function against the pathogenic fungus of corn stalk rot, Fusarium pseudoverticillium, and Bacillus licheniformis HFF-0-C43 with potassium-solubilizing function from corn rhizosphere soil. The two strains are used together to produce synergistic disease resistance and effectively improve the inhibitory effect on the pathogenic fungus of corn stalk rot, Fusarium pseudoverticillium.

[0023] The composite bacterial agent prepared by using the two strains of bacteria provided by the present invention can effectively enhance soil fertility, improve soil environment, and induce plants to produce disease resistance, thereby better achieving the comprehensive prevention and control effects of growth promotion and disease resistance, and realizing the improvement of corn quality, increase of yield, and increase of income. The composite bacterial agent is safe, efficient, pollution-free, and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 is the phylogenetic tree diagram of strain HFF-0-C5;

[0026] Figure 2 This is the phylogenetic tree of strain HFF-0-C43. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0030] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0031] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0032] The Fusarium verticilliodes used in the present invention is provided by the Mycotoxin and Plant Molecular Pathology Laboratory of Hebei Agricultural University.

[0033] Example 1

[0034] 1. Strain Isolation

[0035] The present invention isolates 4 strains of bacteria from the rhizosphere soil of corn, and they are named KF5, HFF-0-C5, K43 and HFF-0-C43 respectively. Among them, KF5 and HFF-0-C5 are antagonistic strains that have an inhibitory effect on the pathogenic fungus of corn stalk rot, Fusarium pseudoverticillium, screened out through a plate confrontation experiment; K43 and HFF-0-C43 are bacteria with potassium-solubilizing function screened out using a potassium-solubilizing medium.

[0036] Among them, strains KF5 and K43 have been disclosed in the document "Screening and identification of biocontrol strains for corn Fusarium stalk rot and development of bacterial agents."

[0037] Potassium-dissolving medium: sucrose 10 g / L, yeast extract 0.5 g / L, ammonium sulfate 1 g / L, disodium hydrogen phosphate 2 g / L, magnesium sulfate heptahydrate 0.5 g / L, calcium carbonate 1 g / L, potassium feldspar powder 1 g / L and agar powder 15 g / L.

[0038] 2. Strain Identification

[0039] (1) Physiological and biochemical identification

[0040] On LB solid medium, the colonies of HFF-0-C5 and HFF-0-C43 were white with irregular surface. Gram staining confirmed that HFF-0-C5 and HFF-0-C43 were Gram-positive strains. Physiological and biochemical identification found that HFF-0-C5 and HFF-0-C43 were positive for methyl red, nitrate reduction, starch hydrolysis, and lactose decomposition; VP determination and indole production were negative.

[0041] (2) Molecular Biological Identification

[0042] The 16s rDNA of the strains were amplified using molecular biological methods with universal primers, and then sequenced and aligned using Blastn to construct a phylogenetic tree. The results are shown in Figure 1 and Figure 2 .

[0043] The results showed that strain HFF-0-C5 was most closely related to Paenibacillus peoriae, with a similarity of more than 99.9%. Combined with physiological and biochemical characteristics, strain HFF-0-C5 was identified as Paenibacillus peoriae. Strain HFF-0-C43 was most closely related to Bacillus licheniformis, and combined with physiological and biochemical characteristics, it was identified as Bacillus licheniformis.

[0044] 3. Strain preservation

[0045] Paenibacillus peoriae HFF-0-C5 was deposited at the General Microbiology Center of China Culture Collection Administration on October 23, 2023. The deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28717.

[0046] Bacillus licheniformis HFF-0-C43 was deposited at the General Microbiology Center of China Culture Collection Administration on October 23, 2023. The deposit address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28718.

[0047] Example 2

[0048] The strains HFF-0-C5 and HFF-0-C43 were mixed and cultured on LB medium for 2 days. The results showed that the growth of strain HFF-0-C43 on LB medium containing strain HFF-0-C5 was the same as that of the control, indicating that the two bacterial strains would not affect each other's growth when cultured at the same time. Therefore, HFF-0-C5 and HFF-0-C43 can be used together.

[0049] The strain HFF-0-C5 was inoculated into fermentation medium A and fermented at 30°C and 160 rpm for 2 days to obtain a fermentation broth. The fermentation broth was centrifuged at 4000 rpm for 10 min to enrich the cells and then resuspended in PBS buffer to a cell concentration of 10 8 cfu / mL to obtain HFF-0-C5 bacterial suspension.

[0050] The strain KF5 was inoculated into fermentation medium A and fermented at 30°C and 160 rpm for 2 days to obtain a fermentation broth. The fermentation broth was centrifuged at 4000 rpm for 10 min to enrich the cells and then resuspended in PBS buffer to a cell concentration of 10 8 cfu / mL to obtain KF5 bacterial suspension.

[0051] The strain HFF-0-C43 was inoculated into fermentation medium B and fermented at 30°C and 160 rpm for 2 days to obtain a fermentation broth. The fermentation broth was centrifuged at 4000 rpm for 10 min to enrich the cells and resuspended in PBS buffer to a cell concentration of 10 8 cfu / mL to obtain HFF-0-C43 bacterial suspension.

[0052] The strain K43 was inoculated into fermentation medium B and fermented at 30°C and 160 rpm for 2 days to obtain a fermentation broth. The fermentation broth was centrifuged at 4000 rpm for 10 min to enrich the cells and then resuspended in PBS buffer to a cell concentration of 10 8 cfu / mL to obtain K43 bacterial suspension.

[0053] Among them, the formula of fermentation medium A is: yeast extract powder 5g / L, ammonium sulfate 7.5g / L and potassium dihydrogen phosphate 5g / L; the formula of fermentation medium B is: yeast extract powder 7.5g / L, trypsin 7.5g / L and magnesium sulfate 5g / L.

[0054] The HFF-0-C5 bacterial suspension and the HFF-0-C43 bacterial suspension were mixed in a volume ratio of 0:1, 1:0, 1:1, 1:2, 2:1, and 2:3 to obtain 5 mixed bacterial agents. The KF5 bacterial suspension and the K43 bacterial suspension were mixed in a volume ratio of 1:0, 1:1, 1:2, 2:1, and 2:3 to obtain 5 mixed bacterial agents, which were then cultured on plates with Fusarium spp. (the amount of composite bacterial solution added to the Oxford cup of each group was the same). The results are shown in Table 1.

[0055] Table 1 Diameters of inhibition zones in each group of plate confrontation experiments

[0056] Volume ratio Diameter of inhibition zone of HFF-0-C5 and HFF-0-C43 compound (cm) Diameter of inhibition zone of KF5 and K43 compound (cm) 0:1 7.8±0.1 7.8±0.1 1:0 1.35±0.21 1.26±0.14 1:1 1.62±0.09 1.44±0.08 1:2 1.22±0.28 1.00±0.13 2:1 1.39±0.14 1.00±0.24 2:3 1.50±0.17 0.94±0.12

[0057] The results showed that different proportions of HFF-0-C5 suspension and HFF-0-C43 suspension could produce an inhibition zone against Fusarium pseudoverticillioides after mixing. Comparison of the antibacterial ability showed that when HFF-0-C5 and HFF-0-C43 were mixed at a volume ratio of 1:1, the antibacterial ability was the strongest, and the diameter of the inhibition zone reached 1.62 cm, which was higher than the diameter of the inhibition zone when the antagonistic bacteria HFF-0-C5 was used alone. This shows that the inhibitory effect of the two bacterial liquids on Fusarium pseudoverticillioides after mixing is better than that of HFF-0-C5 alone. At the same time, compared with the compound effect of KF5 and K43, the antibacterial effect of HFF-0-C5 and HFF-0-C43 after compounding is better.

[0058] The above results show that the antagonistic bacteria HFF-0-C5 and potassium-dissolving bacteria HFF-0-C43 can be combined, and the combination effect is best when HFF-0-C5:HFF-0-C43=1:1.

[0059] Example 3

[0060] The growth-promoting effect of composite microbial agent A (HFF-0-C5 bacterial suspension and HFF-0-C43 bacterial suspension in Example 1 were mixed in a volume ratio of 1:1) and composite microbial agent B (KF5 bacterial suspension and K433 bacterial suspension in Example 1 were mixed in a volume ratio of 1:1) on corn was verified. A greenhouse potted plant experiment was conducted. The composite microbial agent was used for root irrigation when corn grew to the three-leaf stage. Each plant was irrigated with 20 mL of root, and an equal amount of PBS buffer was used as a control. After continuing to culture for 15 days, the corn plant height, stem thickness, root length, fresh weight and other indicators were recorded. The results are shown in Table 2.

[0061] Table 2 Statistical table of indoor growth promotion effects of different treatment groups

[0062]

[0063] The results showed that the root irrigation treatment of compound microbial agent A had better growth than compound microbial agent B and the control. The root length, plant height, leaf length and fresh weight of corn treated with compound microbial agent A were significantly better than those of compound microbial agent B and the control. The research results showed that the compound microbial agent prepared by strains HFF-0-C5 and HFF-0-C43 had a good growth-promoting effect on corn seedlings.

[0064] Example 4

[0065] To verify the control effect of composite bacterial agent A (HFF-0-C5 bacterial suspension and HFF-0-C43 bacterial suspension in Example 1 were mixed in a volume ratio of 1:1) and composite bacterial agent B (KF5 bacterial suspension and K433 bacterial suspension in Example 1 were mixed in a volume ratio of 1:1) on corn stalk rot caused by Fusarium spp., a greenhouse potted plant experiment was conducted, which is described in detail as follows:

[0066] After the diameter of the corn stem grew to 2 cm, the root was irrigated with the composite microbial agent (with an equal amount of PBS buffer as a control), 20 mL per plant. After the root irrigated treatment, the corn stem was inoculated with Fusarium spp. (i.e., the second stem node at the base of the corn was injected at a 45° angle downward with a concentration of 1×10 6 The spore suspension of Fusarium spores with a concentration of 2 mL / mL was added, and the disease was observed after 7 days. The results are shown in Table 3. The results showed that the expansion area of ​​corn stem lesions was significantly inhibited after treatment with composite microbial agent A and composite microbial agent B, and the inhibitory effect of composite microbial agent A was better.

[0067] Table 3 Statistics of the expansion area of ​​corn stem lesions in different treatment groups

[0068]

[0069] Example 5

[0070] The preparation method of the HFF-0-C5 bacterial suspension and the HFF-0-C43 bacterial suspension involved in this embodiment is the same as that in Example 2. The HFF-0-C5 bacterial suspension and the HFF-0-C43 bacterial suspension are mixed evenly in a volume ratio of 1:1 to obtain a composite bacterial liquid.

[0071] After preparing different dosage forms of compound microbial agents, field tests were carried out:

[0072] 1. Liquid bacterial agent: Gum arabic powder, Tween 80 and tea polyphenols were added to the composite bacterial solution to make the final concentrations of the three 0.3wt%, 0.2wt% and 0.03wt% respectively to obtain a liquid bacterial agent (the bacterial concentration of HFF-0-C5 and HFF-0-C43 was 10 8 cfu / mL). The prepared liquid inoculant was used for root irrigation, with 20 mL per plant.

[0073] 2. Granules: In the composite bacterial solution (the bacterial concentration of HFF-0-C5 and HFF-0-C43 is 10 8 cfu / mL) to make the final concentrations of the two 5wt% and 3wt%, respectively, to obtain a mixed suspension, and the mixed suspension was evenly mixed with whole wheat flour at a volume mass ratio of 1:2, granulated using a granulator, and dried in a cool and ventilated place to obtain granules. The prepared granules were applied to holes, and the application amount per plant was the same as that of the liquid inoculant in terms of the amount of live bacteria.

[0074] 3. Coating agent: The composite bacterial solution and the finished film-forming agent (purchased from Beinong Haili Company) were uniformly mixed at a volume ratio of 1:5 to obtain a coating solution, ensuring that the final concentrations of HFF-0-C5 and HFF-0-C43 were both 10 8cfu / mL, sterilize healthy corn seeds, add them to the prepared coating solution, stir quickly with a glass rod to ensure uniform coating, and dry them. Sow the prepared coated seeds.

[0075] After treatment with different dosage forms of compound microbial agents (with no compound microbial agent as the control), various growth indicators of corn, including aboveground plant height, leaf length, leaf width, etc., were investigated at the four-leaf and one-heart stage of corn. The results are shown in Table 4.

[0076] The results showed that compared with the blank control, from the perspective of different dosage forms, the treatment group using the coating agent for seed coating had a better growth-promoting effect in terms of plant height, leaf length, leaf width, stem thickness, etc. than the other dosage forms, and the difference was significant. The second was the granule treatment group, and the third was the liquid bacterial agent treatment.

[0077] Table 4 Effects of different formulations of compound microbial agents on corn seedlings in the field

[0078]

[0079] After the corn matured, 30 ears were randomly selected from each plot. After drying, the number of rows of corn ears, number of kernels per row, ear length, ear diameter, 1000-kernel weight, water content and other related indicators were measured to calculate the corn yield of each treatment. 2 ) = number of plants per mu × number of ear rows × number of grains per row × thousand-grain weight × 8.5 × 10 -1 / (1000×1000).

[0080] As shown in Table 5, the results showed that compared with the blank control, after treatment with different dosage forms of composite bacterial agents, indicators such as the number of corn cob rows and the number of kernels per row were improved to varying degrees. Among them, compared with the control group, the yield of the corn treatment group treated with antagonistic bacteria HFF-0-C5 and potassium-solubilizing bacteria HFF-0-C43 was improved to a certain extent, and the coating agent had the greatest increase in yield, with a significant yield-increasing effect.

[0081] Table 5 Effects of different composite microbial agents on yield

[0082]

[0083] Example 6

[0084] The same as Example 5, except that 30 corns inoculated with Fusarium spp. were randomly selected in each plot at the waxy stage of corn, and the longitudinal stem dissection method was used to observe the lesion area and count the incidence. A disease survey was conducted in each area, and the disease grade of corn was counted. The disease grading standard is shown in Table 6.

[0085] Table 6 Disease classification standards

[0086]

[0087] Disease index = [∑(disease severity level × corresponding number of cases) / (total number of cases investigated × highest disease severity level)] × 100%

[0088] Control effect (%) = [(control group disease index - treatment group disease index) / control group disease index] × 100%

[0089] The results of the control effect evaluation of each treatment group are shown in Table 7. The results show that compared with the blank treatment, the control effect of the composite bacterial agent is better. It can be preliminarily concluded that the mixed treatment of antagonistic bacteria HFF-0-C5 and potassium-dissolving bacteria HFF-0-C43 has a better control effect on stem rot. Among them, the control effect of the treatment group using the coating agent is the highest, reaching 57.48%.

[0090] Table 7 Evaluation of the control effect of different composite microbial agents on corn stalk rot

[0091]

[0092] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A microbial combination for preventing and controlling corn stalk rot and having a growth-promoting function, characterized in that: Including Paenibacillus peoriae HFF-0-C5 and Bacillus licheniformis HFF-0-C43; The Paenibacillus piloriformis HFF-0-C5 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on October 23, 2023, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28717; The Bacillus licheniformis HFF-0-C43 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on October 23, 2023. The deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28718.

2. The microbial combination according to claim 1, characterized in that The quantitative ratio of the Bacillus pierrei HFF-0-C5 and the Bacillus licheniformis HFF-0-C43 is 2:(1-3).

3. The microbial combination according to claim 2, characterized in that: The quantity ratio of the Bacillus pierreiu HFF-0-C5 to the Bacillus licheniformis HFF-0-C43 is 1:

1.

4. Use of the microbial combination as described in any one of claims 1 to 3 in the preparation of a composite bacterial agent with the functions of preventing and controlling corn stalk rot and promoting growth.

5. The use according to claim 4, characterized in that: The composite bacterial agent is a liquid bacterial agent, a coating agent or a granule.

6. A composite bacterial agent with the functions of preventing and controlling corn stalk rot and promoting growth, characterized in that: The active ingredient comprises the microbial combination according to any one of claims 1 to 3.

7. The composite bacterial agent according to claim 6, characterized in that: The composite bacterial agent also includes auxiliary materials.

8. The composite bacterial agent according to claim 7, characterized in that: The compound bacterial agent is in the form of a liquid bacterial agent, a coating agent or a granule.

9. The composite bacterial agent according to claim 1, characterized in that: When the dosage form of the composite bacterial agent is a liquid bacterial agent, the auxiliary materials are gum arabic powder, Tween 80 and tea polyphenols; When the dosage form of the composite bacterial agent is a coating agent, the auxiliary material is a film-forming agent; When the dosage form of the composite bacterial agent is granules, the auxiliary materials are kaolin and tyrosine.

10. Use of the microbial combination according to any one of claims 1 to 3 or the composite bacterial agent according to any one of claims 6 to 9 in preventing and controlling corn stalk rot and / or increasing corn yield.

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