Biocontrol fungus and biocontrol inoculant for preventing and treating anthracnose of camellia oleifera and application of biocontrol fungus and biocontrol inoculant

Abstract

The invention belongs to the technical field of biopesticides, and relates to a biocontrol fungus and a biocontrol inoculant for preventing and treating anthracnose of camellia oleifera and application of the biocontrol fungus and the biocontrol inoculant. According to the invention, a CV strain of coniochaeta velutina is separated and screened from microbial resources on healthy tea-oil tree leaves, and the CV strain is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.41439. The invention further discloses a preparation method of the CV strain of the coniochaeta velutina and the application of the CV strain of the coniochaeta velutina. The CV strain provided by the invention has a good antagonistic effect on colletotrichum gloeosporioides, alternaria alternata and botryosphaeria dothidea, and particularly, the bacteriostasis rate of the CV strain on the colletotrichum gloeosporioides, which is a main pathogenic bacterium of camellia oleifera anthracnose, reaches 67.44%. The biocontrol fungus CV strain and the biocontrol inoculant provided by the invention not only can be used for preventing and treating camellia oleifera anthracnose, but also have potential application prospects in the aspect of preventing and treating plant diseases caused by colletotrichum gloeosporioides, alternaria alternata or botryosphaeria dothidea.

Description

Technical Field

[0001] The invention belongs to the technical field of biological pesticides and relates to a biocontrol fungus for preventing and controlling anthracnose of oil-tea tea, a biocontrol fungal agent and application thereof. Background Art

[0002] Camellia oleifera is native to my country. It is the largest woody edible oil tree species in my country and one of the four largest woody edible oil tree species in the world. It has high economic value and broad market prospects. It is mainly planted in Hunan, Jiangxi, Guangxi, Zhejiang and Hubei. Camellia oleifera disease is one of the main problems that restrict the high yield and high quality of Camellia oleifera. Camellia oleifera anthracnose can cause Camellia oleifera to fall leaves and fruits, and in severe cases, the whole plant will die. It is the main disease with the highest incidence rate in Camellia oleifera. According to statistics, the annual loss of Camellia oleifera due to Camellia oleifera anthracnose is about 10-25% of the total output. Therefore, in-depth research on the prevention and control measures of Camellia oleifera anthracnose is of great significance to improving the yield and quality of Camellia oleifera.

[0003] The pathogens that cause anthracnose of oil tea include Colletotrichum gloeosporioides, Alternaria alternata and Botryosphaeria dothidea. At present, the prevention and control of oil tea diseases is still mainly chemical control. Although the use of chemical control of oil tea anthracnose can quickly reduce losses, due to the strong adaptability of the pathogen of oil tea anthracnose, it is not only easy to cause the development of drug resistance of the pathogen of oil tea anthracnose, but also the large-dose use of chemical pesticides seriously pollutes the ecological environment, and also increases the amount of pesticide residues in tea oil, reduces the quality of tea oil, and affects the healthy development of the oil tea industry.

[0004] Endophytes exist in plants in the form of symbiotic microorganisms, and have great potential in promoting plant health, enhancing crop growth momentum and improving the adaptability of diseased plants. Endophytes have significant disease prevention and control functions, and studies have found that many plant endophytes have antibacterial activity. If the natural antibacterial properties of endophytes are utilized, a potential biological pesticide can be developed to solve the problem of organic pesticides damaging the ecological environment. Currently, there are few types of biocontrol bacteria that can be used to control anthracnose in oil tea, and the actual application effect in the actual field is not good. Therefore, it is of great significance to this field to find a safe, low-toxic and efficient endophyte strain for the control of anthracnose in oil tea.

[0005] Coniochaeta strains are widely found in the natural environment. It has been reported that Coniochaeta strains have insecticidal activity against root-knot nematodes, antibacterial effects against Ralstonia solanacearum, Pseudomonas syringae, Xanthomonas oryzae variants and Rhizoctonia solani, and can be used to prevent and control wheat stem rot. Coniochaeta strains can also be combined with biochar to remediate contaminated soil, so they have broad application potential in agriculture and biomedicine. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a biocontrol fungus, a biocontrol agent and its application for preventing and controlling oil-tea anthracnose. The present invention provides a CV strain of Coniochaeta velutina, which first reveals that the CV strain has an antagonistic effect on Colletotrichum gloeosporioides, Alternaria alternata and Botrytis cinerea, which cause oil-tea anthracnose. The CV strain has a significant antagonistic effect on Colletotrichum gloeosporioides, with an inhibition rate of 67.44%, and can be used as a biocontrol agent for the prevention and control of plant diseases.

[0007] The first aspect of the present invention provides a biocontrol fungus for preventing and controlling anthracnose of oil tea. The biocontrol fungus is a Coniochaeta velutina CV strain, which is deposited in the General Microbiological Center of China National Microbiological Culture Collection Committee with a deposit number of CGMCC No.41439.

[0008] The CV strain originated from the natural microbial flora on the leaves of Camellia oleifera plants in Sima Guang Camellia Oil Garden in Guangshan County, Xinyang City.

[0009] Furthermore, the nucleotide sequence of the CV strain is shown in SEQ ID NO.1.

[0010] The second aspect of the present invention provides an application of the above-mentioned CV strain in preventing and treating anthracnose of tea oil tree.

[0011] Furthermore, the CV strain is used to inhibit the growth of Colletotrichum gloeosporioides, Alternaria alternata and Botryosphaeria dothidea, which cause anthracnose of oil tea.

[0012] The third aspect of the present invention provides a CV strain fermentation broth, which is obtained by the following preparation method:

[0013] The CV strain described in the first aspect of the present invention is inoculated into a potato glucose liquid culture medium, and cultured at 25-28° C. for 3-7 days to obtain the CV strain fermentation liquid.

[0014] Preferably, the culture temperature is 27°C and the culture time is 7 days.

[0015] The fourth aspect of the present invention provides a biocontrol agent, which contains the CV strain described in the first aspect of the present invention or the fermentation liquid of the CV strain described in the third aspect of the present invention, and agriculturally acceptable adjuvants or additives.

[0016] Furthermore, the biocontrol agent may be in the form of any one of biological pesticides, biological fertilizers, biocontrol agents and antimicrobial agents.

[0017] Furthermore, the biocontrol agent is a liquid preparation or a powder.

[0018] Furthermore, the number of viable spores of the CV strain contained in each milliliter or gram of the biocontrol agent is 5×10 7 ~2×10 8 indivual.

[0019] Furthermore, the liquid preparation is a fermentation broth containing the CV strain or antibacterial active substances secreted by the CV strain; the powder is a freeze-dried powder containing the CV strain or the CV strain fermentation broth.

[0020] The fifth aspect of the present invention provides an application of the CV strain fermentation broth described in the third aspect of the present invention or the biocontrol agent described in the fourth aspect of the present invention in preventing and controlling anthracnose of tea oil.

[0021] Furthermore, the application method comprises the following steps:

[0022] Before the onset of anthracnose of oil-tea camellia and in the early stage of the disease, the CV strain fermentation liquid or the biocontrol agent is sprayed on the leaves and trunks of the oil-tea camellia;

[0023] The spraying method is: spray once every 15 days, for a total of 3 times.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention screened out a CV strain of Conchocera pubescens from the microbial resources on healthy tea leaves. The CV strain provided by the present invention has an inhibitory effect on three pathogenic bacteria, namely, Colletotrichum gloeosporioides, Alternaria alternata and Botrytis cinerea, which cause anthracnose of tea leaves, with inhibition rates reaching 67.44%, 67.16% and 66.19%, respectively. The results of plate inhibition experiments, in vitro leaf wound inoculation and field control experiments show that the CV strain provided by the present invention has a significant control effect on anthracnose of tea leaves, greatly reduces the incidence of anthracnose of tea leaves, and is an excellent biological control microorganism for anthracnose of tea leaves.

[0026] (2) As a fungus, CV strain is easier to preserve and culture, and can be used to develop new biological agents for the prevention and control of anthracnose in oil tea, providing important material accumulation and theoretical reference for the biological control of anthracnose in oil tea. CV strain belongs to the species of Triatochaeta, and the present invention enriches the antibacterial range of Triatochaeta strains, which has important practical significance for the development of new uses of Triatochaeta strains.

[0027] (3) The CV strain fermentation liquid provided by the present invention has a simple and easy-to-control fermentation process, a low fermentation liquid preparation cost, is non-toxic and harmless to humans and animals, has no toxicity to crops, is green and environmentally friendly, provides favorable conditions for the development of new biological agents, and has important application value in the field of plant disease prevention and control in agricultural production.

[0028] Description of biological material deposit

[0029] The CV strain in the present invention is classified and named: Coniochaetavelutina, and its Latin name is: Coniochaetavelutina. It was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on August 19, 2024, with the deposit number CGMCC No.41439. The address of the depository is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The morphology of the CV strain on the plate, the left picture shows the front morphology of the colony, and the right picture shows the back morphology of the colony.

[0031] Figure 2 This is the microscopic structure of the CV strain.

[0032] Figure 3 Phylogenetic tree of CV strains.

[0033] Figure 4 These are the antibacterial effect diagrams of CV strain on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea in dishes; among them, A, B, and C are the antibacterial effects of CV strain on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea after 3 days of culture, D, E, and F are the antibacterial effects of CV strain on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea after 4 days of culture, and G, H, and I are the antibacterial effects of CV strain on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea after 5 days of culture; the two upper plates in each small picture are parallel tests of the confrontation culture plates of CV strain and pathogens (treatment group), and the lower plates are plates only inoculated with pathogens (control group).

[0034] Figure 5 This is the fermentation broth after culturing CV strain. The two bottles of fermentation broth in the figure are parallel experiments.

[0035] Figure 6 Schematic diagram of the results of the in vitro leaf protection test of CV strain fermentation liquid against Colletotrichum oleifera; the upper row shows the growth conditions of leaves not inoculated with Colletotrichum gloeosporioides, leaves inoculated with Colletotrichum gloeosporioides and sprayed with sterile water, and leaves inoculated with Colletotrichum gloeosporioides and sprayed with CV fermentation liquid on the first day; the lower row shows the growth conditions of leaves not inoculated with Colletotrichum gloeosporioides, leaves inoculated with Colletotrichum gloeosporioides and sprayed with sterile water, and leaves inoculated with Colletotrichum gloeosporioides and sprayed with CV fermentation liquid on the 7th day of culture. DETAILED DESCRIPTION

[0036] 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 the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0038] Camellia oleifera anthracnose is one of the most devastating diseases of Camellia oleifera. The current means of controlling Camellia oleifera anthracnose are highly dependent on organic chemicals, but the long-term and large-scale use of organic chemicals will have an impact on biological health and the environment. Currently, the types of microorganisms used to control Camellia oleifera anthracnose are limited, and the control effect of Camellia oleifera anthracnose is difficult to meet expectations.

[0039] The invention provides a biocontrol fungus and biocontrol agent for preventing and controlling anthracnose of oil tea, and the application thereof. The invention first collects healthy oil tea leaves from an oil tea garden, and screens a biocontrol fungus CV strain having an antibacterial effect on gloeosporium anthracnose, botrytis cinerea, and alternaria by separation, purification, and plate confrontation test. The biocontrol fungus is identified as Coniochaeta velutina by morphology and molecular biology, and the deposit number is CGMCC No. 41439. The plate confrontation experiment shows that the CV strain can inhibit the growth of gloeosporium anthracnose, botrytis cinerea, and alternaria, and the inhibition rates reach 66.44%, 67.16%, and 66.19%, respectively. Then, the control effect of the CV strain on anthracnose of oil tea is determined by inoculation of detached leaves with wounds and field control experiments, and it is found that the CV strain can effectively reduce the area of ​​leaf lesions and shows a good control effect on anthracnose of oil tea.

[0040] Example 1: Acquisition and identification of CV strains

[0041] 1. Preliminary screening of bacterial strains

[0042] Sima Guang Oil Tea Garden in Guangshan County, Xinyang City was chosen as the experimental plot, where Changlin No. 4 oil tea variety was mainly planted. Leaves were selected from 5-year-old healthy oil tea plants as experimental materials.

[0043] Prepare PDA medium for strain culture. The PDA medium formula is 200 g potato, 20 g glucose, 20 g agar and 1 L distilled water.

[0044] Take fresh and healthy tea oil leaf, first rinse the leaves with sterile water, then cut the leaves into 3mm×3mm tissue blocks with a sterilized scalpel, disinfect them with 75% ethanol for 2 minutes, soak them in 2% sodium hypochlorite for 1 minute, then rinse them repeatedly with sterile water for 3 times, transfer the disinfected tissue blocks to PDA culture medium, put 3 tissue blocks in each culture dish, and mark them.

[0045] Place the culture dish in a biochemical incubator and culture it continuously at 27°C for 3 days. Fungi will grow around the tissue blocks in the culture dish. Pick up the fungal hyphae and transfer them to a new culture dish. Place the culture dish in a biochemical incubator and culture it continuously at 27°C for 5 days. Repeat this step several times to obtain a single fungal strain.

[0046] 2. Strain rescreening

[0047] The plate confrontation method was used for rescreening. On PDA medium, the screened fungal strains were cultured in pairs with Colletotrichum gloeosporioides, Alternaria alternata and Botryosphaeria dothidea.

[0048] Use a puncher to punch out a 5mm diameter cake from the cultured pathogenic bacteria, and place the cake in the center of the PDA culture medium. Use the same punch to punch out the cake of the screened fungal strain and place it in the upper, lower, left and right directions about 2cm away from the pathogenic bacteria. Mark them as the treatment group and set up 3 replicates. The control group is composed of normally grown pathogenic bacteria and the screened fungal strains.

[0049] The inoculation time of the control group and the treatment group was kept consistent. After marking, they were inverted and cultured in a constant temperature box. After culturing for 3 days, the growth of the treatment group and the control group was observed, and the colony diameters of the treatment group and the control group were measured with a vernier caliper. The biocontrol fungi with the largest inhibitory diameter were screened out, and the screened biocontrol fungi strains were placed in a freezing tube containing 30% glycerol (the volume ratio of the biocontrol fungi strain to glycerol was 1:1), and frozen at -80°C.

[0050] 3. Strain identification

[0051] (1) Flat plate observation

[0052] The screened biocontrol fungal strains were cultured on PDA plates, and the color, texture and other characteristics of the colonies were observed.

[0053] like Figure 1 As shown, after 7 days of culture on the PDA plate, the mycelium edge of the strain was white, the central area was yellow, and the mycelium was relatively developed.

[0054] (2) Scanning electron microscopy observation

[0055] The endophytes with the strongest antibacterial ability screened out were cultured on PDA plates. After 2 days, colonies at appropriate locations on the plates were selected and cut into small pieces of about 4 mm × 6 mm with a surgical blade to prepare samples; the samples were immersed in 4% glutaraldehyde and fixed overnight at 4°C; they were immersed in PBS buffer with a pH value of 6.8 and a concentration of 0.1 M for 10 minutes, rinsed with 90% ethanol for 15 minutes, and repeated 4 times; dehydrated with 100% ethanol for 30 minutes, repeated 3 times; dried in a carbon dioxide critical point dryer; placed in an ion sputtering instrument for gold spraying; and the prepared samples were observed under a S-4800 field emission scanning electron microscope at a voltage of 10.0 kV.

[0056] like Figure 2 As shown, the hyphae of CV bacteria grow into a circle on the surface of the culture medium. The hyphae gradually entwine and mature to form dark brown ascocarps. The vegetative hyphae are transparent and 1.5 to 2.5 μm wide. The conidiophores degenerate into spore-producing cells. The conidia are transparent, single-celled, smooth-walled and cylindrical.

[0057] (3) Identification of strain rDNA ITS sequences

[0058] The target fungal DNA was extracted using a fungal genome total DNA extraction kit (purchased from Jiangsu Kangwei Century Biotechnology Co., Ltd.), and the specific operation steps were according to the instruction manual;

[0059] The fungal identification universal primers ITS1 and ITS4 were used to amplify the rDNA ITS gene sequence of the strain by PCR, and the amplified product was detected by 1.0% agarose gel electrophoresis to determine the target band;

[0060] The nucleotide sequences of ITS1 and ITS4 are shown in SEQ ID No. 1 and SEQ ID No. 2, respectively.

[0061] SEQ ID No.1: 5'-TCCGTAGGTGAACCTGCG-3';

[0062] SEQ ID No.2: 5'-TCCTCCGCTTATTGATATGC-3';

[0063] Gel recovery was performed according to the instructions of the Gene JET Gel Recovery Kit (purchased from Thermo Fisher Scientific);

[0064] The recovered product was connected to the vector pMD18-T (purchased from TaKaRa) and the DNA fragment was cloned;

[0065] The plasmid was extracted using the plasmid extraction kit T-PM0201 (purchased from Nanjing Qingke Biotechnology Co., Ltd.) and sent to Sangon Biotechnology Co., Ltd. for sequencing;

[0066] The sequencing result is shown in SEQ ID NO.3, SEQ ID NO.3:

[0067] .

[0068] The obtained sequences were copied to the NCBI database, and the rDNA ITS sequences of related strains were obtained by BLAST comparison. The rDNA ITS sequences with higher homology were screened out, and the phylogenetic tree was constructed using MEGA5 software (such as Figure 3The rDNA ITS sequencing results of the strain showed a homology of 99.6% with that of Coniochaeta velutina. Based on the morphological observation and 16S rDNA sequence analysis results, the strain was identified as Coniochaeta velutina and named as CV strain.

[0069] Example 2: In-dish antibacterial activity test of CV strain

[0070] On PDA medium, the CV strain was cultured in pairs with Colletotrichum gloeosporioides, Alternaria alternata and Botrytis cinerea.

[0071] The cultured pathogenic bacteria were made into a 5mm cake and placed in the center of the PDA medium. The CV strain was also made into a cake and placed in the upper, lower, left and right directions about 2cm away from the pathogenic bacteria. They were marked as the treatment group and repeated three times. The control group was the normally growing pathogenic bacteria. The inoculation time of the control group and the treatment group was kept consistent. After marking, they were inverted and cultured in a constant temperature box. The growth of the treatment group and the control group was observed after 3d, 4d and 5d of culture, and the colony diameter of the strains in the treatment group and the control group was measured with a vernier caliper.

[0072] Table 1 shows the antibacterial rates of CV strain against Colletotrichum gloeosporioides, Alternaria alternata and Botrytis cinerea after CV strain was co-cultured with Colletotrichum gloeosporioides, Alternaria alternata and Botrytis cinerea for 5 days. The antibacterial rates were calculated according to the following formula:

[0073] Inhibition rate (%) = (colony diameter of control group - colony diameter of treatment group) / colony diameter of control group × 100%.

[0074] Table 1 Inhibition rate of biocontrol strain CV against three pathogenic bacteria

[0075] Colony diameter of treatment group / cm Colony diameter of control group / cm Antibacterial rate / % Colletotrichum gloeosporioides 2.10 6.45 67.44％ Alternaria 2.20 6.7 67.16％ Botrytis cinerea 2.40 7.1 66.19％

[0076] Figure 4 The inhibition of CV strain on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea. Figure 4 It can be clearly seen from Table 1 that, compared with the control group, the biocontrol fungus CV strain in the treatment group had a significant inhibitory effect on the pathogenic bacteria of Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea, and the inhibition rates were 67.44%, 67.16%, and 66.19%, respectively.

[0077] Example 3: Control effect of CV strain on anthracnose of tea oil

[0078] 1. Preparation of CV strain fermentation broth

[0079] In the clean bench, the cultured CV strain was punched out into a 5 mm diameter cake with a hole puncher, and the cakes were picked and placed in a conical bottle containing PDB medium. Five cakes were placed in each bottle, and a total of 9 bottles were made ( Figure 5 The conical flask was covered with a breathable sealing film and fixed in a shaker at 27°C and 150 rpm for 7 days until the number of viable spores per ml was about 2×10 8 indivual.

[0080] 2. In vitro leaf protection effect experiment

[0081] Select oil tea seedlings of the same size and growth, pick 10 healthy oil tea leaves from each pot plant, use a sterile syringe to lightly pierce the leaf epidermis with 3 small holes on the left and right sides of the main vein of the leaf; punch the cultured gloeosporium anthracnose fungus into a 5mm diameter cake, pick the cake with a needle, stick these cakes close to the pinholes of the oil tea leaves, spray the detached leaves with CV strain fermentation liquid and sterile water once, record the changes in the diameter of the lesions on the detached leaves, Table 2 shows the average diseased area of ​​the detached leaves on the 7th day, and the formula for calculating the control effect of the detached leaves is:

[0082] Control effect (%) = (the diseased area of ​​the control group - the diseased area of ​​the treatment group) / the diseased area of ​​the control group × 100%.

[0083] Table 2 Analysis of the inhibitory effect of CV strain fermentation broth on detached leaves on pathogenic bacteria

[0084] <![CDATA[Lesion area (cm 2 )]]> Control effect% Sterile water 10.28 - CV strain fermentation broth 3.80 63.03％

[0085] Note: “-” in the table means no statistics on control effect.

[0086] Figure 6 The results of the experiment on the efficacy of CV strain fermentation liquid on the detached leaves of tea oil anthracnose are shown in Figure 2. Figure 6 As shown in Table 2, on the 7th day, the leaves of the tea tree inoculated with Colletotrichum gloeosporioides and treated with sterile water showed severe large-area necrotic spots, with an average disease area of ​​10.28 cm 2 The lesion area of ​​tea leaves in the group inoculated with CV fermentation liquid was significantly reduced, with an average lesion area of ​​3.80 cm 2 .

[0087] 3. Field control effectiveness test

[0088] In Sima Guang Oil Tea Garden, Guangshan County, Henan Province, the Changlin No. 4 oil tea variety was selected as the test object. In mid-September, 2L of CV strain fermentation liquid was applied to each oil tea plant each time by spraying leaves. The spraying interval was 15 days, and a total of 3 sprays were applied. Conventional management was used as a control. After application, the disease situation of each treated leaf was investigated and recorded, and the control effect of CV strain fermentation liquid on Colletotrichum gloeosporioides, Alternaria alternata, and Botrytis cinerea was calculated according to the following formula:

[0089] Field control effect % = (control diseased leaf rate - treatment diseased leaf rate) / control diseased leaf rate × 100%.

[0090] Table 3 Field control effectiveness test results

[0091]

[0092] Note: “-” in the table means no statistics on efficacy.

[0093] From the statistical results of the field control test in Table 3, it can be seen that the fermentation liquid of the CV strain showed a good control effect on anthracnose of oil-tea camellia, with a control efficiency of 50.10%.

[0094] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A biocontrol fungus for preventing and controlling anthracnose of oil-tea tree, characterized in that: The biocontrol fungus is the Coniochaeta velutina CV strain, which is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration, with a deposit number of CGMCC No.41439.

2. Use of the CV strain according to claim 1 in preventing and treating anthracnose of tea oil plants.

3. The use according to claim 2, characterized in that: The CV strain is used to inhibit the growth of Colletotrichum gloeosporioides, Alternaria alternata and Botryosphaeria dothidea, which cause anthracnose of oil tea.

4. A CV strain fermentation broth, characterized in that The fermentation broth is obtained by the following preparation method: The CV strain described in claim 1 is inoculated into a potato glucose liquid culture medium, and cultured at 25-28° C. for 3-7 days to obtain the CV strain fermentation liquid.

5. A biocontrol agent, characterized in that: The biocontrol agent contains the CV strain according to claim 1 or the CV strain fermentation liquid according to claim 4, and agriculturally acceptable auxiliary materials or adjuvants.

6. The biocontrol agent according to claim 5, characterized in that The biocontrol agent is a liquid preparation or a powder.

7. The biocontrol agent according to claim 5, characterized in that The number of viable spores of the CV strain contained per milliliter or per gram of the biocontrol agent is 5×10 7 ~2×10 8 indivual.

8. The biocontrol agent according to claim 5, characterized in that The liquid preparation is a fermentation liquid containing the CV strain or antibacterial active substances secreted by the CV strain; the powder is a freeze-dried powder containing the CV strain or the fermentation liquid of the CV strain.

9. Use of the CV strain fermentation liquid according to claim 4 or the biocontrol agent according to claim 5 in preventing and controlling anthracnose of oil-tea tea.

10. The use according to claim 9, characterized in that: The application method is: before the onset of anthracnose of oil-tea camellia and in the early stage of the disease, the CV strain fermentation liquid or the biocontrol agent is sprayed on the leaves and trunks of the oil-tea camellia.

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