Complex microbial inoculant for preventing and treating potato scab and application of complex microbial inoculant

Abstract

The invention belongs to the technical field of potato scab prevention and treatment, and particularly relates to a complex microbial inoculant for preventing and treating potato scab and application of the complex microbial inoculant. The complex microbial inoculant provided by the invention comprises bacillus velezensis BEV2 and bacillus atrophaeus FM2-4, wherein the effective viable bacterium concentration of the bacillus velezensis BEV2 and the effective viable bacterium concentration of the bacillus atrophaeus FM2-4 in the complex microbial inoculant are respectively 1-3 * 10 < 8 > CFU / m. The complex microbial inoculant provided by the invention can effectively prevent and treat the potato scab, reduce the morbidity of the potato scab and improve the yield and quality of potatoes, and has the advantages of being not easily influenced by the environment and being harmless to the environment.

Description

Technical Field

[0001] The invention belongs to the field of potato scab prevention and treatment, and particularly relates to a composite bacterial agent for preventing and treating potato scab and application thereof. Background Art

[0002] Potato scab is a soil-borne and seed-borne disease caused by Streptomyces spp., which is widely distributed in potato-growing areas around the world. Potato scab mainly harms potato tubers. The pathogen invades from the lenticels. In the early stage of the disease, brown spots form on the surface of the tubers, and the spots expand to form large round or irregular patches in the later stage. The tissues around the infection point become corky, the surface of the tuber becomes rough, and the center of the lesion is convex or concave, sometimes penetrating below the cortex, with a depth of up to 7mm. Potato scab not only affects the appearance quality and sales price of potatoes, but also causes delays in potato emergence and even causes seedling death in severe cases, resulting in a decrease in yield, bringing huge economic losses to the potato industry. In addition, drought climate, alkaline soil, sandy loam soil, and continuous cropping will increase the incidence of potato scab.

[0003] At present, the main control methods for potato scab include chemical control and biological control. Among them, biological control is an environmentally friendly disease control method, which mainly uses bacteria, fungi, actinomycetes, etc. Biological control has the advantages of safety to non-target organisms, small toxic side effects, good environmental compatibility, and continuous action on harmful organisms. However, biological control of a single strain of bacteria has the disadvantages of slow field control effect, unsatisfactory control effect, and susceptibility to environmental influences.

[0004] Therefore, how to provide a composite bacterial agent for preventing and treating potato scab, wherein the strains in the composite bacterial agent can produce a synergistic effect, has become an urgent problem to be solved in the art. Summary of the invention

[0005] In view of this, the present invention provides a composite bacterial agent for preventing and treating potato scab that can produce a synergistic effect, which specifically includes the following technical solutions:

[0006] A composite bacterial agent for preventing and treating potato scab, the composite bacterial agent comprising Bacillus Velez subtilis BEV2 and Bacillus atrophaeus FM2-4, wherein the effective live bacterial concentrations of Bacillus Velez subtilis BEV2 and Bacillus atrophaeus FM2-4 in the composite bacterial agent are 1 to 3×10 8 CFU / mL.

[0007] Preferably, the effective live bacteria concentration of Bacillus Velezii BEV2 in the composite bacterial agent is 1×10 8CFU / mL; the effective live bacterial concentration of Bacillus atrophaeus FM2-4 in the composite bacterial agent is 1×10 8 CFU / mL.

[0008] The present invention also provides a method for preparing the composite bacterial agent as described above, comprising the following steps:

[0009] The seed liquid of Bacillus velez BEV2 and the seed liquid of Bacillus atrophaeus FM2-4 were inoculated into LB medium at a volume ratio of 1% for shaking culture to obtain Bacillus velez BEV2 bacterial liquid and Bacillus atrophaeus FM2-4 bacterial liquid;

[0010] The bacterial liquid of Bacillus Velezii BEV2 and the bacterial liquid of Bacillus atrophaeus FM2-4 are mixed to obtain the composite bacterial agent.

[0011] Preferably, the seed solution of Bacillus velez BEV2 and the seed solution of Bacillus atrophaeus FM2-4 are cultured in LB medium until the effective viable bacteria concentration is 10 8 CFU / mL.

[0012] Preferably, the culture conditions of the shaking culture are: 37° C. and 200 rpm.

[0013] The present invention also provides the use of the composite bacterial agent as described above or the composite bacterial agent prepared by the preparation method in one or more of preventing and controlling potato scab, increasing potato yield and improving potato quality.

[0014] The present invention also provides a method for preventing and controlling potato scab, increasing potato yield and improving potato quality, which is carried out using the composite bacterial agent as described above or the composite bacterial agent prepared by the preparation method, and comprises the following steps:

[0015] Applying the composite bacterial agent for the first time at the potato seedling stage;

[0016] Applying the composite bacterial agent for the second time during the potato tuber stage;

[0017] The composite bacterial agent was applied for the third time during the potato tuber enlargement period.

[0018] Preferably, the first application of the composite bacterial agent, the second application of the composite bacterial agent, and the third application of the composite bacterial agent are all applied by drip irrigation.

[0019] Preferably, the drip irrigation speed is 1500-2500 mL / h.

[0020] Preferably, the application amount of the composite bacterial agent for the first application, the second application and the third application is 8000-12000 mL / mu respectively.

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a composite bacterial agent for preventing and treating potato scab, wherein the composite bacterial agent comprises Bacillus Velez subtilis BEV2 and Bacillus atrophaeus FM2-4, and the effective live bacteria concentration ratio of Bacillus Velez subtilis BEV2 and Bacillus atrophaeus FM2-4 in the composite bacterial agent is 1 to 3×10 8 CFU / mL. Compared with a single microbial agent, the composite microbial agent provided by the present invention produces a synergistic effect. The composite microbial agent provided by the present invention is used to control potato scab, which can not only improve the control effect of potato scab, but also improve the yield and quality of potatoes. The present invention provides a new idea for field control of potatoes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0024] Figure 1 This is a schematic diagram of the effects of different groups in preventing and treating potato scab in Example 6 of the present invention;

[0025] Figure 2 This is a schematic diagram of the yield-increasing effect of the composite bacterial agent on potatoes in Example 7 of the present invention;

[0026] Among them, the left side of the control group and treatment group pictures in the figure shows the small potatoes produced under different treatments, and the right side shows the large potatoes produced under different treatments;

[0027] Figure 3 This is a schematic diagram of the effects of different treatments on the growth of radish seedlings inoculated with potato scab pathogens in Example 8 of the present invention;

[0028] Figure 4 This is a schematic diagram of the effects of different treatments on potato plant height in Example 8 of the present invention;

[0029] Among them, A is the plant height data bar graph; B is the plant phenotype;

[0030] Figure 5 This is a bar graph showing the effects of different treatments on the stem girth of potato plants in Example 8 of the present invention;

[0031] Figure 6 This is a schematic diagram of the effects of different treatments on potato root length in Example 8 of the present invention;

[0032] Among them, A is the bar graph of root length data; B is the plant phenotype.

[0033] Biological deposit information

[0034] Bacillus atrophaeus FM2-4, biological classification name: Bacillus atrophaeus, was deposited in the General Microbiology Center of China Microorganism Culture Collection (CGMCC) on November 22, 2024. The deposit address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No.32749. DETAILED DESCRIPTION

[0035] The present invention provides a composite bacterial agent for preventing and treating potato scab, wherein the composite bacterial agent comprises Bacillus Velez subtilis BEV2 and Bacillus atrophaeus FM2-4, wherein the effective live bacteria concentration ratio of Bacillus Velez subtilis BEV2 to Bacillus atrophaeus FM2-4 is 1 to 3×10 8 CFU / mL.

[0036] As an embodiment, in the composite bacterial agent, Bacillus BEV2 is the Bacillus Velezii BEV2 in the paper "Shang Shuyan, Wang Jinhui, Guo Weiwei, Zhang Dai, Pan Yang, Zhao Dongmei, Li Qian, Zhu Jiehua, Yang Zhihui. Screening of biocontrol Bacillus for preventing and controlling potato scab caused by various streptomyces [J]. China Potato, 2023, (Issue 6)"; the Bacillus atrophaeus FM2-4 is the Bacillus FM2-4 in the paper "Shang Shuyan, Wang Jinhui, Guo Weiwei, Zhang Dai, Pan Yang, Zhao Dongmei, Li Qian, Zhu Jiehua, Yang Zhihui. Screening of biocontrol Bacillus for preventing and controlling potato scab caused by various streptomyces [J]. China Potato, 2023, (Issue 6)", and its deposit number is CGMCC No. 32749. As an embodiment, the effective live bacterial concentrations of Bacillus Velezii BEV2 and Bacillus atrophaeus FM2-4 are 1×10 8 As an embodiment, the effective viable bacterial concentrations of Bacillus Velezii BEV2 and Bacillus atrophaeus FM2-4 can be 1×10 8 CFU / mL, 2×10 8 CFU / mL and 3×10 8 Any of CFU / mL.

[0037] The present invention also provides a method for preparing the composite bacterial agent as described above, comprising the following steps:

[0038] The seed liquid of Bacillus velez BEV2 and the seed liquid of Bacillus atrophaeus FM2-4 are inoculated into LB culture medium at a volume ratio of 1% for shaking culture to obtain Bacillus velez BEV2 bacterial liquid and Bacillus atrophaeus FM2-4 bacterial liquid; the Bacillus velez BEV2 bacterial liquid and the Bacillus atrophaeus FM2-4 bacterial liquid are mixed to obtain the composite bacterial agent.

[0039] As an embodiment, the seed solution of Bacillus Velezii BEV2 and the seed solution of Bacillus atrophaeus FM2-4 are cultured in LB medium until the effective viable bacteria concentration is 10 8 CFU / mL. As an embodiment, the culture conditions of the shaking culture are: 37°C, 200rpm. As an embodiment, the Bacillus Velezii BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution are mixed at a ratio of 1:1 in terms of effective live bacteria concentration.

[0040] The present invention also provides the use of the composite bacterial agent as described above or the composite bacterial agent prepared by the preparation method in one or more of preventing and controlling potato scab, increasing potato yield and improving potato quality.

[0041] The present invention also provides a method for preventing and controlling potato scab, increasing potato yield and improving potato quality, which is carried out using the composite bacterial agent as described above or the composite bacterial agent prepared by the preparation method, and comprises the following steps:

[0042] The composite bacterial agent is applied for the first time at the potato seedling stage; the composite bacterial agent is applied for the second time at the potato tuber setting stage; and the composite bacterial agent is applied for the third time at the potato tuber swelling stage.

[0043] As an embodiment, the application method of the first application of the composite microbial agent, the second application of the composite microbial agent, and the third application of the composite microbial agent are all drip irrigation. As an embodiment, the drip irrigation speed is 1500-2500mL / h. As an embodiment, the drip irrigation speed can be any one of 1500mL / h, 2000mL / h, and 2500mL / h. As an embodiment, the application amount of the first application of the composite microbial agent, the second application of the composite microbial agent, and the third application of the composite microbial agent is 8000-12000mL / mu, respectively. As an embodiment, the application amount of the first application of the composite microbial agent, the second application of the composite microbial agent, and the third application of the composite microbial agent can be any one of 8000mL / mu, 10000mL / mu, and 12000mL / mu, respectively.

[0044] In order to further illustrate the present invention, the composite bacterial agent for preventing and treating potato scab provided by the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1 A composite bacterial agent for preventing and treating potato scab

[0046] The composite bacterial agent includes Bacillus Velez subtilis BEV2 bacterial solution and Bacillus atrophaeus FM2-4 bacterial solution, and the effective live bacteria concentration ratio of the Bacillus Velez subtilis BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution is 1:1.

[0047] In the composite bacterial agent, the concentrations of the Bacillus Velezii BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution were 1×10 8 CFU / mL.

[0048] Example 2 A composite bacterial agent for preventing and treating potato scab

[0049] The composite bacterial agent includes Bacillus Velez subtilis BEV2 bacterial solution and Bacillus atrophaeus FM2-4 bacterial solution, and the effective live bacteria concentration ratio of the Bacillus Velez subtilis BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution is 1:1.

[0050] In the composite bacterial agent, the concentrations of the Bacillus Velezii BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution were 2×10 8 CFU / mL.

[0051] Example 3 A composite bacterial agent for preventing and treating potato scab

[0052] The composite bacterial agent includes Bacillus Velez subtilis BEV2 bacterial solution and Bacillus atrophaeus FM2-4 bacterial solution, and the effective live bacteria concentration ratio of the Bacillus Velez subtilis BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution is 1:1.

[0053] In the composite bacterial agent, the concentrations of the Bacillus Velezii BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution were 3×10 8 CFU / mL.

[0054] Example 4 Preparation method of a composite bacterial agent

[0055] The seed liquid of Bacillus Velezii BEV2 was inoculated into liquid LB medium at a volume ratio of 1:99, and the culture was shaken at 37°C, 200 rpm, and an ambient humidity of 55% for 9 h without shielding from light until the bacterial liquid concentration reached 1×10 8 CFU / mL, and the bacterial solution of Bacillus Velezii BEV2 was obtained;

[0056] The seed liquid of Bacillus atrophaeus FM2-4 was inoculated into liquid LB medium at a volume ratio of 1:99, and cultured at 37°C, 200 rpm, and an ambient humidity of 55% for 9 h without shielding from light until the bacterial liquid concentration reached 1×10 8 CFU / mL, and the bacterial solution of Bacillus atrophaeus FM2-4 was obtained;

[0057] The Bacillus Velez BEV2 bacterial solution and the Bacillus atrophaeus FM2-4 bacterial solution were mixed in a volume ratio of 1:1 to obtain the composite bacterial agent.

[0058] Example 5 A method for preventing and treating potato scab

[0059] The compound bacterial agent was applied for the first time at the potato seedling stage, and the application method was drip irrigation. The dosage of the compound bacterial agent was 10000mL, and the drip irrigation speed was 2000mL / h.

[0060] The second application of compound bacteria agent was carried out during the potato tuber stage. The application method was drip irrigation. The dosage of compound bacteria agent was 10000mL and the drip irrigation speed was 2000mL / h.

[0061] The compound bacterial agent was applied for the third time during the potato tuber swelling period. The application method was drip irrigation. The dosage of the compound bacterial agent was 10,000 mL and the drip irrigation speed was 2,000 mL / h.

[0062] Example 6 Verification test of the effect of compound bacterial agent on preventing and controlling potato scab

[0063] The test site was at the Jiacheng Company base in Changli County, and the potato variety used in the test was Chaojiu. The test set up 3 treatments in total. Treatment 1 was treated with the chemical agent 20% bronopol, and treatment 2 was treated with the composite bacterial agent described in Example 1 of the present invention. CK was used as a blank control and only sprayed with clean water. The above treatments were prepared using the method described in Example 4, and the agent type and application amount were adjusted according to the contents shown in Table 1; 4 potato planting areas were set up for each treatment. The potato planting areas were randomly distributed, with 2 rows in each plot, 33 cm plant spacing, 65 cm row spacing, 39 m length per row, and an area of ​​50.7 m 2 , 240 bud blocks were sown in each plot.

[0064] The application time during the seedling stage is March 15, and the application time during the tuber stage is April 17; the application time during the tuber expansion stage is May 7. The specific plan is shown in Table 1. It should be noted that when applying the agents described in Table 1, the amount of agent required for each plot is calculated based on the per mu usage and the plot area, and the chemical agent or compound bacterial agent is diluted to 10L before application.

[0065] Table 1 Test plan for test agents

[0066]

[0067] At the time of potato harvest, potatoes in an area of ​​10 m long ridges and 0.65 m wide were randomly surveyed in each plot. The number and area of ​​lesions on the potato surface were investigated and the number of diseased potatoes of each grade was recorded in each plot. Diseases were graded according to the grading standards in Table 2. Potatoes of different groups after grading were photographed. A group of photographed results for each treatment was randomly selected for display. The results are shown in Tables 3 and Figure 1 As shown;

[0068] Table 2 Grading standards for potato scab

[0069]

[0070]

[0071] Table 3 Potato yield at different levels under different treatments

[0072]

[0073] From Table 3 and Figure 1 It can be seen that after the potatoes were treated with the composite bacterial agent of the present invention, not only the incidence of potato scab was reduced, but only 1 to 3 levels of mild disease were found, most of the potatoes showed no disease or 1 level of disease, and the number of cracked potatoes was significantly reduced, and the potato quality was significantly improved; in the group 1 treated with chemical control agents, although most of the potatoes showed 1 to 2 levels of mild disease, a small number of potatoes showed 5 levels of severe disease, and the number of cracked potatoes was large, and the potato quality was poor. The potatoes in the CK group were all diseased at levels 0 to 5, and even the number of potatoes with 4 to 5 levels of severe disease was high, and the number of cracked potatoes was also large, and the potato quality of the CK group was very poor.

[0074] The incidence rate, disease index, and control effect of potato scab in the area of ​​10m×0.65m as mentioned above were measured in each plot, and the field survey data were preliminarily statistically organized using Excel software. At the same time, the disease index, control effect and other experimental data were calculated, and then SPSS27.0 was used to perform significant difference analysis on the disease index and other data. The results are summarized in Table 4.

[0075] Incidence rate (%) = (number of diseased tubers / total number of investigated tubers) × 100%;

[0076] Disease index = ∑ (number of stems at each disease level × representative value of that disease level) / (total number of stems surveyed × highest level representative value) × 100;

[0077] Control effect (%) = (control disease index - treatment disease index) / control disease index × 100%.

[0078] Table 4 The control effect of different treatments on potato scab

[0079]

[0080]

[0081] As shown in Table 4, the disease index of potato scab in the water control was 34.66, indicating that the disease of potato scab in the area was serious. There were significant differences between the disease index of treatment 1 and treatment 2 and the disease index of CK (p < 0.05), and each treatment had a certain control effect on potato scab. However, the control effect of treatment 2 using the composite bacterial agent was significantly higher than that of treatment 1, with a control effect of up to 59.35%.

[0082] Example 7 Verification test of the growth-promoting effect of compound bacterial agent

[0083] The test site was conducted at the experimental base of the third factory of Hebei Agricultural University, and the potato variety used in the test was Zhongshu No. 5. This test set up the treatments shown in Table 4. Treatment 3 was treated with the composite bacterial agent as described in Example 1. The treatment methods of CK and treatment 3 were the same, except that when applying the pesticide in treatment 3, the CK group only dripped water. Each treatment was set up with 4 repetitions, each repetition was a small area, the length of the small area was 10m, and the sowing row spacing was 0.7m. The agricultural operations during the potato growing season were consistent with the conventional potato field production management. The specific application plan is shown in Table 5.

[0084] Table 5 Potato growth promotion test plan

[0085] Processing Name Pharmaceutical ingredients Amount per mu (mL) Application period Application method Process 3 Compound Bacterial Agent 10000 Tuber stage Drip irrigation CK Clear water control - Tuber stage Drip irrigation

[0086] When potatoes are harvested, the yield of potatoes in an area of ​​10m×0.65m is measured and pictures are taken. The results are as follows: Figure 2 shown.

[0087] Depend on Figure 2 It can be seen that compared with the CK group, after the potatoes were treated with the composite bacterial agent of the present invention, the potato yield was significantly increased compared with the water control group, especially the large potato rate was significantly increased. The composite bacterial agent of the present invention can improve the yield and quality of potatoes.

[0088] The weight of potatoes in the 10m×0.65m area as mentioned above was measured to calculate the yield per mu. The field survey data were preliminarily statistically organized using Excel software. The yield, yield increase, large potato yield increase rate and other experimental data were calculated. SPSS27.0 was then used to perform a significant difference analysis on the yield and other data. The results are shown in Table 6.

[0089] Table 6 Effect of compound bacterial agent on growth promotion of potato

[0090]

[0091]

[0092] As can be seen from Table 6, the composite bacterial agent of the present invention has a certain growth-promoting effect on potatoes. The per-acre yield of CK is 1696.68±105.76 kg, and the per-acre yield after the composite bacterial agent treatment in treatment 3 is 1914.30±83.37 kg, with an increase rate of 12.83%.

[0093] Example 8: Verification test of the synergistic effect of compound bacterial agents

[0094] The antagonistic effect of the compound Bacillus sp. BEV2+FM2-4 was tested by using the radish seedling test of the "Shawo Radish" variety. The radish seeds were soaked in 0.26% sodium hypochlorite solution for 10 minutes, then rinsed with sterile water three times, and the excess water on the seeds was absorbed with sterile filter paper. The pretreated radish seeds were placed in a culture dish, on which were placed three layers of sterile filter paper moistened with sterile water, and germinated in a dark incubator at 25°C for 24 hours.

[0095] After the radish sprouts, select seeds with similar states and place them in a tissue culture test tube pre-set with 15mL 1% water agar. Put 3 seeds in each tissue culture test tube, divided into 5 treatments, 3 replicates for each treatment, and 15 groups of tissue culture test tubes are set; the experimental group is allocated to drop 200μL of Bacillus Velez BEV2 bacterial solution as shown in Example 4, 200μL of Bacillus atrophaeus FM2-4 bacterial solution as shown in Example 4, or 200μL of BEV2+FM2-4 composite bacterial agent as shown in Example 4, and inoculate the pathogenic spore suspension of potato. The positive control group is added with the pathogenic spore suspension of potato scab alone, and the CK group is only added with sterile water.

[0096] Each treatment was placed in a light incubator at 25°C, 16 h light, 8 h dark for cultivation. After 7 days of cultivation, the root length and seedling length of the radish seedlings were measured, and the data were analyzed using SPSS27.0. The results are shown in Table 7 and Figure 3 shown.

[0097] Table 7 Antagonistic effect of compound bacterial agent BEV2+FM2-4 on scab pathogen

[0098] deal with Strain name Average length of radish seedlings (cm) Average root length of radish seedlings (cm) CK - 7.7±1.7a 5.5±0.7a Scab infection S.scabies 2.0±0.7d 0.9±0.3c BEV2 bacterial agent S.scabies 5.4±0.8c 2.0±0.4b FM2-4 microbial agent S.scabies 5.0±0.7c 2.0±0.7b BEV2+FM2-4 compound bacterial agent S.scabies 6.8±1.5b 2.5±0.6b

[0099] As shown in Table 7, the seedling length and root length of the radish seedlings in the clean water treatment group were 7.7±1.7cm and 5.5±0.7cm, respectively, and the seedling length and root length of the radish seedlings inoculated with potato scab pathogens alone were 2.0±0.7cm and 0.9±0.3cm, respectively. It can be seen that potato scab pathogens have a significant inhibitory effect on the seedling length and root length of radish seedlings. The seedling length and root length of the radish seedlings in the group inoculated with the compound bacterial agent BEV2+FM2-4 were 6.8±1.5cm and 2.5±0.6cm, respectively, which were significantly higher than the seedling length and root length of the group inoculated with S.scabies alone. The seedling length of the group inoculated with the compound bacterial agent BEV2+FM2-4 was significantly different from that of the BEV2 and FM2-4 groups inoculated with single microbial agents, but the difference in root length was not significant. This shows that the compound bacterial agents BEV2+FM2-4, BEV2, and FM2-4 all have obvious antagonistic effects on the scab pathogen S. scabies, but the compound bacterial agent BEV2+FM2-4 has a better antagonistic effect on the scab pathogen S. scabies, and there is a synergistic effect between the BEV2 and FM2-4 bacterial agents.

[0100] The synergistic effect of the composite bacterial agent of the present invention was verified by potato seedlings, and the technical scheme is as follows:

[0101] The potato variety used in the experiment was Holland XV. Four treatment groups were set up in this experiment, namely the clean water control CK group, the BEV2 bacterial agent treatment group, the FM2-4 bacterial agent treatment group and the compound bacterial agent BEV2+FM2-4 treatment group. In the BEV2 bacterial agent treatment group, 100 mL of the bacterial agent was added by root irrigation 7 days after potato planting; in the FM2-4 bacterial agent treatment group, 100 mL of the bacterial agent was added by root irrigation 7 days after potato planting; in the compound bacterial agent BEV2+FM2-4 treatment group, 100 mL of the compound bacterial agent was added by root irrigation 7 days after potato planting. The compound bacterial agent was applied after mixing 50 mL of BEV2 bacterial agent and 50 mL of FM2-4 bacterial solution. The CK group applied an equal amount of clean water. The field management methods were all routine operations in the potato planting field. The above potatoes were cultured until 30 days after the root irrigation treatment with the bacterial solution, and the potato growth was recorded. The results are as follows Figures 4 to 6 shown.

[0102] Depend on Figure 4It can be seen that the height of potato plants treated with the compound microbial agent BEV2+FM2-4 is significantly higher than that of the water control group. Among them, after root irrigation treatment of the single microbial agent BEV2 and FM2-4 treatment groups, the height of potato plants was 56.2±3.0cm and 51.2±4.7cm respectively; the compound microbial agent BEV2+FM2-4 treatment group had the strongest growth-promoting effect on the height of potato plants, with an average value of 57.1±4.8cm, which was significantly higher than the FM2-4 treatment alone, and had no significant difference from the effect of BEV2 treatment alone. It can be seen that the composite microbial agent of the present invention has a synergistic effect.

[0103] Depend on Figure 5 It can be seen that the stem circumference of potato plants treated with the compound bacterial agent BEV2+FM2-4 was significantly higher than that of the water control, indicating that the compound bacterial agent BEV2+FM2-4 had a significant effect on the expansion of stem circumference, with an average stem circumference of 3.9±1.0cm, while the stem circumference of the water control was 2.9±1.0cm. The average stem circumference of potato plants treated with BEV2 and FM2-4 alone was 3.7±0.7cm and 3.5±1.0cm, respectively.

[0104] Depend on Figure 6 It can be seen that the root length of potato plants treated with the compound bacterial agent BEV2+FM2-4 was significantly higher than that of the water control, indicating that the compound bacterial agent BEV2+FM2-4 has a certain promoting effect on potato root growth. The average root length of potato plants treated with BEV2 was 47.8±7.7cm; the average root length of the FM2-4 treatment group was 44.8±4.2cm; the average stem circumference of the compound bacterial agent BEV2+FM2-4 treatment group reached 48.0±1.7cm.

[0105] In summary, the composite bacterial agent of the present invention is safe and pollution-free, can effectively reduce the occurrence of potato scab, and can also increase potato yield. Even compared with the existing chemical control agents for potato scab, the composite bacterial agent of the present invention shows a more excellent control effect, and the present invention provides a new idea for field control of potato scab.

[0106] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments like this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A composite bacterial agent for preventing and treating potato scab, characterized in that: The composite bacterial agent comprises Bacillus subtilis BEV2 and Bacillus subtilis FM2-4, and the effective live bacterial concentrations of Bacillus subtilis BEV2 and Bacillus subtilis FM2-4 in the composite bacterial agent are 1 to 3×10 8 CFU / mL.

2. The composite bacterial agent according to claim 1, characterized in that The effective live bacterial concentration of Bacillus sp. BEV2 in the composite bacterial agent is 1×10 8 CFU / mL; the effective live bacterial concentration of Bacillus atrophaeus FM2-4 in the composite bacterial agent is 1×10 8 CFU / mL.

3. The method for preparing the composite bacterial agent according to claim 1 or 2, characterized in that: The steps include: The seed liquid of Bacillus subtilis BEV2 and the seed liquid of Bacillus subtilis FM2-4 were inoculated into LB medium at a volume ratio of 1% for shaking culture to obtain Bacillus subtilis BEV2 bacterial liquid and Bacillus subtilis FM2-4 bacterial liquid; The Bacillus subtilis BEV2 bacterial solution and the Bacillus subtilis FM2-4 bacterial solution are mixed to obtain the composite bacterial agent.

4. The preparation method according to claim 3, characterized in that: The seed liquid of Bacillus Velezii BEV2 and the seed liquid of Bacillus atrophaeus FM2-4 were cultured in LB medium until the effective viable bacteria concentration was 10 8 CFU / mL.

5. The preparation method according to claim 3, characterized in that: The culture conditions of the shaking culture are: 37° C. and 200 rpm.

6. Use of the composite bacterial agent according to claim 1 or 2 or the composite bacterial agent prepared by the preparation method according to any one of claims 3 to 5 in one or more of preventing and controlling potato scab, increasing potato yield and improving potato quality.

7. A method for preventing and controlling potato scab, increasing potato yield and improving potato quality, characterized in that: The method comprises the following steps: Applying the composite bacterial agent for the first time at the potato seedling stage; Applying the composite bacterial agent for the second time during the potato tuber stage; The composite bacterial agent was applied for the third time during the potato tuber enlargement period.

8. The method according to claim 7, characterized in that The first application of the composite bacterial agent, the second application of the composite bacterial agent and the third application of the composite bacterial agent are all applied by drip irrigation.

9. The method according to claim 8, characterized in that The drip irrigation speed is 1500-2500 mL / h.

10. The method according to claim 7, characterized in that The application amount of the composite bacterial agent for the first application, the second application and the third application is 8000-12000 mL / mu respectively.

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