A bacterium-chemical composition for preventing and treating potato scab and application thereof

Abstract

This invention belongs to the field of potato scab control technology, specifically relating to a fungal-agent composition for controlling potato scab and its application. The fungal-agent composition for controlling potato scab provided by this invention comprises the following raw materials: a chemical control agent for potato scab and a compound fungal agent; the volume ratio of the chemical control agent to the compound fungal agent is 75-150:5000; the compound fungal agent includes *Bacillus belyceta* BEV2 and *Bacillus atrophus* FM2-4. Using the fungal-agent composition of this invention can reduce the dosage of chemical agents by at least half, while providing rapid, long-lasting, and effective control of potato scab, and also taking into account the advantages of environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of potato scab control technology, specifically relating to a fungal-agent composition for controlling potato scab and its application. Background Technology

[0002] Potato scab is a soil-borne and seed-borne disease caused by various Streptomyces pp. It occurs widely in potato-growing areas around the world, affecting not only the appearance and quality of potatoes and their market price, but also, in severe cases, delaying seedling emergence and even causing seedling death, resulting in reduced yields and huge economic losses to the potato industry.

[0003] Currently, potato scab is mainly controlled through chemical or biological methods during potato cultivation. Chemical control primarily relies on chemical agents, such as broad-spectrum fungicides like copper sulfate, captan, copper oxychloride, and mancozeb. While these agents can control the severity of potato scab to some extent, they also have some adverse effects, such as soil and water pollution.

[0004] In addition, biological control of potato scab typically employs strains such as Trichoderma, Bacillus subtilis, and Bacillus amyloliquefaciens. These strains are effective against potato scab, safe against non-target organisms, have low toxicity, good environmental compatibility, and long-lasting action against pests. However, single-strain biological control has drawbacks such as slow field efficacy, unsatisfactory control results, and susceptibility to environmental influences.

[0005] Therefore, how to provide a method for controlling potato scab that is fast-acting, effective, and environmentally friendly has become an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the problems of existing technologies for controlling potato scab, such as environmental pollution, slow control speed, and unsatisfactory effects, this invention provides a fungal-pesticide composition for controlling potato scab and its application. This fungal-pesticide composition can rapidly and effectively control potato scab, and has the advantages of low dosage and environmental friendliness. The specific technical solutions of the fungal-pesticide composition for controlling potato scab described in this invention are as follows:

[0007] A fungal composition for controlling potato scab disease, comprising the following raw materials:

[0008] Chemical control agents and compound inoculants for potato scab;

[0009] The volume ratio of the chemical control agent for potato scab to the compound inoculant is 75-150:5000;

[0010] The compound bacterial agent includes Bacillus vesiculosus BEV2 and Bacillus atrophicus FM2-4, and the effective viable bacterial concentrations of Bacillus vesiculosus BEV2 and Bacillus atrophicus FM2-4 in the compound bacterial agent are 1-3 × 10⁻⁶, respectively. 8 CFU / mL;

[0011] The Bacillus atrophus FM2-4 has the accession number CGMCC No. 32749.

[0012] Preferably, the chemical control agent for potato scab includes fludioxonil, fluazinam, or bromonitol.

[0013] Preferably, when the chemical control agent for potato scab is fludioxonil, the fludioxonil is a 2.5% fludioxonil preparation with a mass concentration of 2.5%, and the volume ratio of the 2.5% fludioxonil preparation to the compound microbial agent is 150:5000.

[0014] Preferably, when the chemical control agent for potato scab is fluazinam, the fluazinam is a 50% fluazinam preparation, and the volume ratio of the 50% fluazinam preparation to the compound microbial agent is 75:5000.

[0015] Preferably, when the chemical control agent for potato scab is bromonitol, the bromonitol is a 20% bromonitol preparation, and the volume ratio of the 20% bromonitol preparation to the compound microbial agent is 100:5000.

[0016] The present invention also provides the application of the fungal composition described above in the prevention and control of potato scab.

[0017] The present invention also provides a method for preventing and controlling potato scab, which uses the fungal composition described above for prevention and control, and includes the following steps:

[0018] The fungal composition is applied for the first time during the potato planting period, for the second time during the potato tuber formation period, and for the third time during the potato tuber enlargement period.

[0019] Preferably, the chemical control agent and the compound fungicide for potato scab are applied separately during the first, second, and third applications.

[0020] Preferably, the first application is applied by trenching, the second application is applied by spraying, and the third application is applied by spraying.

[0021] Preferably, when the fungal-drug composition is applied for the first time, the application rate of the chemical control agent for potato scab is 75-150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu.

[0022] When the fungal-drug composition is applied for the second time, the application rate of the chemical control agent for potato scab is 75-150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu.

[0023] When applying the fungal-drug combination for the third time, the application rate of the chemical control agent for potato scab is 75-150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention provides a fungal-agent composition for controlling potato scab, comprising a chemical control agent for potato scab and a compound fungal agent; the volume ratio of the chemical control agent to the compound fungal agent is 75-150:5000; the compound fungal agent includes Bacillus berberis BEV2 and Bacillus atrophicus FM2-4. Using the fungal-agent composition for controlling potato scab described in this invention can improve the control effect on potato scab while reducing the dosage of chemical control agents by half, thereby reducing the incidence of potato scab and achieving both disease control and environmental friendliness. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0027] Figure 1 This is a schematic diagram showing the disease severity grading of potato scab after different treatment groups in Example 5 of the present invention.

[0028] Biological Preservation Information

[0029] Bacillus atrophaeus FM2-4 was deposited on November 22, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 32749. Detailed Implementation

[0030] This invention provides a fungal composition for preventing and controlling potato scab, comprising the following raw materials:

[0031] A chemical control agent and a compound microbial agent for potato scab; the volume ratio of the chemical control agent to the compound microbial agent is 75-150:5000; the compound microbial agent includes Bacillus vesicularis BEV2 and Bacillus atrophicus FM2-4, and the effective viable cell concentrations of Bacillus vesicularis BEV2 and Bacillus atrophicus FM2-4 are 1-3 × 10⁻⁶ respectively. 8 CFU / mL.

[0032] In one embodiment, the chemical control agent for potato scab includes fludioxonil, fluazinam, or bromonitol. In one embodiment, the fludioxonil is a 2.5% fludioxonil formulation, for example, a 2.5% fludioxonil suspension; the bromonitol is a 20% bromonitol formulation, for example, a 20% bromonitol wettable powder; and the fludioxonil is a 50% bromonitol formulation, for example, a 50% bromonitol suspension. The volume ratio of the chemical control agent for potato scab to the compound fungicide is based on the volume of the 2.5% fludioxonil formulation, the 20% bromonitol formulation, and the 50% bromonitol formulation. In one embodiment, when the chemical control agent for potato scab is fludioxonil, the fludioxonil is a 2.5% fludioxonil formulation, and the volume ratio of the 2.5% fludioxonil formulation to the compound fungicide is 150:5000. In one embodiment, when the chemical control agent for potato scab is fluazinam, the fluazinam is a 50% fluazinam formulation, and the volume ratio of the 50% fluazinam formulation to the compound microbial agent is 75:5000. In another embodiment, when the chemical control agent for potato scab is bromonitol, the bromonitol is a 20% bromonitol formulation, and the volume ratio of the 20% bromonitol formulation to the compound microbial agent is 100:5000. In one embodiment, the compound microbial agent includes *Bacillus bellis* BEV2 and *Bacillus atrophicus* FM2-4. *Bacillus bellis* BEV2 is the same as described in the paper "Shang Shuyan, Wang Jinhui, Guo Weiwei, Zhang Dai, Pan Yang, Zhao Dongmei, Li Qian, Zhu Jiehua, Yang Zhihui. Screening of biocontrol bacilli for controlling potato scab caused by various *Streptomyces* [J]. *Chinese Potato*, 2023, (Issue 6)". The *Bacillus atrophicus* FM2-4 is the same as described in the paper "Shang Shuyan, Wang Jinhui, Guo Weiwei, Zhang Dai, Pan Yang, Zhao Dongmei, Li Qian, Zhu Jiehua, Yang Zhihui. Screening of biocontrol bacilli for controlling potato scab caused by various *Streptomyces* [J]. *Chinese Potato*, 2023, (Issue 6)", and its preservation number is CGMCC No. 32749. The effective viable cell concentrations of Bacillus vesiculus BEV2 and Bacillus atrophus FM2-4 were 1–3 × 10⁻⁶. 8 CFU / mL. As one embodiment, the effective viable cell concentrations of *Bacillus belyssae* BEV2 and *Bacillus atrophus* FM2-4 can be 1×10⁻⁶ CFU / mL.8 CFU / mL, 2×10 8 CFU / mL or 3×10 8 CFU / mL. In a specific embodiment, the chemical control agent for potato scab is 2.5% fludioxonil, where 2.5% fludioxonil refers to a commercially available drug with a mass concentration of 2.5%, and the volume ratio of 2.5% fludioxonil to the compound bacterial agent is 150:5000. The effective viable cell concentrations of Bacillus vesiculosus BEV2 and Bacillus atrophus FM2-4 are each 1×10⁻⁶. 8 CFU / mL. In another specific embodiment, the chemical control agent for potato scab is 50% fluazinam, where 50% fluazinam refers to a commercially available drug with a mass concentration of 50% fluazinam. The volume ratio of the 50% fluazinam to the compound microbial agent is 75:5000, and the effective viable cell concentrations of Bacillus vesiculosus BEV2 and Bacillus atrophus FM2-4 in the compound microbial agent are 1×10⁻⁶ CFU / mL. 8 CFU / mL. In another specific embodiment, the chemical control agent for potato scab is 20% bromonitol, where 20% bromonitol refers to a bromonitol mass concentration of 20% in the commercial drug, and the volume ratio of the 20% bromonitol to the compound bacterial agent is 100:5000. The effective viable bacterial concentrations of Bacillus vesiculosus BEV2 and Bacillus atrophus FM2-4 in the compound bacterial agent are 1×10⁻⁶ CFU / mL. 8 CFU / mL.

[0033] As one embodiment, the preparation process of the compound bacterial agent of the present invention includes the following steps: seed cultures of Bacillus belye BEV2 and Bacillus atrophicus FM2-4 are inoculated into a culture medium for cultivation until the effective viable bacterial concentration reaches 10. 8 CFU / mL. As one embodiment, the present invention preferably inoculates *Bacillus belyeceae* BEV2 seed culture and *Bacillus atrophicus* FM2-4 seed culture into liquid LB medium at a volume ratio of 1% and performs shake culture. As one embodiment, the shake culture conditions of the present invention are preferably 37°C and 40%–70% humidity for 9 hours.

[0034] The present invention also provides the application of the fungal composition described above in the prevention and control of potato scab.

[0035] The present invention also provides a method for preventing and controlling potato scab, which uses the fungal composition described above for prevention and control, and includes the following steps:

[0036] The fungal composition is applied for the first time during the potato planting period, for the second time during the potato tuber formation period, and for the third time during the potato tuber enlargement period.

[0037] This invention involves the first application of the fungal agent composition during the potato planting period. In one embodiment, the first application is performed by furrow application, with the chemical control agent for potato scab and the compound fungal agent in the composition applied separately. In another embodiment, the second application is performed by spraying, with the chemical control agent for potato scab and the compound fungal agent in the composition applied separately. In yet another embodiment, the second application is performed by spraying, with the chemical control agent for potato scab and the compound fungal agent in the composition applied separately.

[0038] In one embodiment, when the fungal-pesticide composition is applied for the first time, the amount of the chemical control agent for potato scab is 75-150 mL, and the amount of the compound fungal agent is 5000 mL; in another embodiment, when the fungal-pesticide composition is applied for the first time, the amount of the chemical control agent for potato scab can be 75 mL / mu, 100 mL / mu, or 150 mL / mu.

[0039] In one embodiment, when the fungal-pesticide composition is applied for the second time, the amount of the chemical control agent for potato scab is 75-150 mL, and the amount of the compound fungal agent is 5000 mL; in another embodiment, when the fungal-pesticide composition is applied for the second time, the amount of the chemical control agent for potato scab can be 75 mL / mu, 100 mL / mu, or 150 mL / mu.

[0040] In one embodiment, during the third application of the fungal-pesticide composition, the application rate of the chemical control agent for potato scab is 75-150 mL, and the application rate of the compound fungal agent is 5000 mL. In another embodiment, during the third application of the fungal-pesticide composition, the application rate of the chemical control agent for potato scab can be 75 mL / mu, 100 mL / mu, or 150 mL / mu.

[0041] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a fungal composition for preventing and controlling potato scab disease and its application, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1: A fungal drug composition

[0043] The raw materials for the fungal-drug composition are chemical control agents for potato scab and compound fungal agents;

[0044] A chemical control agent with a mass concentration of 2.5% fludioxonil was used for potato scab, and it was applied at a volume ratio of 150:5000 between 2.5% fludioxonil and the compound fungicide.

[0045] The raw materials for the compound bacterial agent are Bacillus belyssae BEV2 and Bacillus atrophus FM2-4. The concentration of Bacillus belyssae BEV2 in the compound bacterial agent is 1×10⁻⁶. 8 CFU / mL, the concentration of the Bacillus atrophus FM2-4 is 1×10⁻⁶. 8 CFU / mL.

[0046] The preparation process of the compound bacterial agent is as follows: Seed cultures of *Bacillus belyeceae* BEV2 and *Bacillus atrophicus* FM2-4 are inoculated into liquid LB medium at a volume ratio of 1%, and cultured by shaking until the effective viable cell concentrations of *Bacillus belyeceae* BEV2 and *Bacillus atrophicus* FM2-4 reach 10⁻⁶. 8 Stop culturing at CFU / mL. Culture conditions for shaking culture are 37℃, 200 rpm, and 40–70% humidity.

[0047] Example 2: A fungal drug composition

[0048] The raw materials for the fungal-agent composition are chemical control agents for potato scab and compound fungal agents;

[0049] Use 50% fluazinam as the chemical control agent for potato scab, and apply it at a volume ratio of 75:5000 between 50% fluazinam and the compound fungicide.

[0050] The raw materials and preparation process of the compound bacterial agent are the same as in Example 1.

[0051] Example 3: A fungal drug composition

[0052] The raw materials for the fungal-agent composition are chemical control agents for potato scab and compound fungal agents;

[0053] Using 20% ​​bromonitol as the chemical control agent for potato scab, apply it at a volume ratio of 100:5000 between 20% bromonitol and the compound microbial agent.

[0054] The raw materials and preparation process of the compound bacterial agent are the same as in Example 1.

[0055] Example 4: Field test of the control effects of different control methods on potato scab.

[0056] The experiment was conducted at a potato scab disease nursery in Houjingbuzi Village, Zhangbei County, using the Shaboti potato variety. Eight treatment groups and one control group were set up, with three replicates for each group, each replicate being a plot. Different pesticides were used for different groups, as detailed in Table 1. Treatments 1-9 were administered according to the method for controlling potato scab described in Example 4, the difference being that the pesticide components and dosages used for different treatments were adjusted according to the pesticide components and dosages shown in Table 1. The experiment was conducted using a randomized block design, with each replicate being a plot. Potatoes were planted with a row spacing of 65 cm and a plant spacing of 20 cm, with two rows planted per plot. Each plot was 3.8 m long and approximately 5.32 m² in area. 2 The total area is 143.64m². 2 It is approximately 0.215 acres.

[0057] The application time for pesticides was May 7th during the sowing period; June 25th during the tuber formation period; and July 13th during the tuber enlargement period. A disease survey was conducted on August 28th, the potato harvest date. Specific plans are shown in Table 1. The dosages mentioned in Table 1 are for each spraying session. All spraying was carried out using an electric sprayer. It should be noted that when applying the pesticides mentioned in Table 1, the dosage required for each plot was calculated based on the dosage per acre and the plot area. Then, the pesticide was diluted using a two-stage dilution method, and the compound microbial agent or chemical agent was finally diluted to 10L according to the plot area.

[0058] Table 1 Experimental protocols for treatments 1–9

[0059]

[0060]

[0061] Note: In treatments 5-7, chemical agents and compound microbial agents are applied separately, and the order of dosage is the same for the chemical control agent dosage for potato scab + the compound microbial agent dosage.

[0062] At potato harvest, potatoes in each plot were surveyed. For each treatment, the average of the survey data from three plots was used as the survey result. The number and area of ​​surface lesions were investigated, and the number of diseased potatoes at each level was recorded for each plot. The disease was classified according to the potato scab grading standard shown in Table 2. The potato scab grading results for different treatment groups are shown in Table 3. After classifying the potato scab grading, photos were taken, and one group was randomly selected from each treatment for display. The results are as follows: Figure 1 As shown.

[0063] Calculate the prevention and control effect, incidence rate, and disease index using the formulas shown below:

[0064] Incidence rate (%) = (Number of diseased tubers / Total number of tubers surveyed) × 100%;

[0065] Disease index = ∑(number of tubers at each disease level × representative value of that disease level) / (total number of tubers surveyed × highest level representative value) × 100;

[0066] Prevention and control effect (%) = (control disease index - treatment disease index) / control disease index × 100.

[0067] The field survey data were preliminarily statistically analyzed and organized using Excel software. At the same time, the experimental data such as disease index and control effect were calculated. Then, SPSS 27.0 was used to perform a significant difference analysis on the disease index and other data. The results are shown in Table 3.

[0068] Table 2 Grading Criteria for Potato Scab

[0069]

[0070]

[0071] Table 3. Grading results of potato scab disease in different treatment groups.

[0072]

[0073] Note: In Table 3, a, b, and c represent the significance of differences in the mean disease index between different groups, and the same letter indicates that they are at the same level.

[0074] According to Table 3 and Figure 1 The results showed that potato scab disease was more severe in the water control group, with severity levels ranging from 1 to 5. Among single chemical treatments, 50% fluazinam showed the best control effect, with only mild severity levels 1-2. Among single microbial inoculant treatments, the compound inoculant showed the best control effect, with most affected potatoes exhibiting level 1 disease and only one sample showing level 2 disease. Among inoculant-chemical combination treatments, the 2.5% fludioxonil + compound inoculant treatment showed the best control effect, with most potatoes exhibiting level 1-2 disease and only one sample showing level 2 disease.

[0075] As shown in Table 3, among single chemical agents, 50% fluazinam showed the best control effect against potato scab, with a control efficacy of 65.73%; followed by 20% bromonitrile, while 2.5% fludioxonil showed the worst control effect, at 52.40%. Regarding microbial agents, the compound inoculant BEV2+FM2-4 showed a control efficacy of 70.17% against potato scab, while Bacillus amyloliquefaciens QST713 (Zhuorun), as a commercially available biocontrol control, showed a control efficacy of 57.90%. In terms of combined use of fungicides and pesticides, 2.5% fludioxonil + the compound inoculant BEV2+FM2-4 showed the best control efficacy against potato scab, at 72.57%. The fungal-pesticide composition provided by this invention exhibits a synergistic effect between chemical control agents for potato scab and the compound inoculant of this invention. Compared with treatments 1-3, treatments 5-7 improved the control effect on potato scab by halving the dosage of chemical control drugs and compound inoculants.

[0076] In summary, this invention provides a fungal-pesticide composition for controlling potato scab. Using this composition reduces the use of chemical pesticides for potato scab control, and the compound fungal agent and chemical agents can produce a synergistic effect, improving field control efficacy against potato scab, enhancing the overall control effect, reducing the incidence of potato scab, and achieving both disease control and environmental friendliness.

[0077] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments without creative effort, as shown in these embodiments, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A fungal composition for controlling potato scab, characterized in that, Including the following raw materials: Chemical control agents and compound inoculants for potato scab; The chemical control agent for potato scab is a 2.5% fludioxonil preparation; The volume ratio of the 2.5% fludioxonil preparation and the compound bacterial agent is 150:5000. The compound bacterial agent consists of Bacillus belyceta var. BEV2 and Bacillus atrophicus FM2-4, with effective viable cell concentrations of Bacillus belyceta var. BEV2 and Bacillus atrophicus FM2-4 in the compound bacterial agent being 1~3×10⁻⁶. 8 CFU / mL; The preservation number of the Bacillus atrophus FM2-4 is CGMCC No. 32749; The B. vesicle BEV2 described is accessed under the number CGMCC No. 26741.

2. The use of the fungal composition according to claim 1 in the prevention and control of potato scab.

3. A method for preventing and controlling potato scab, characterized in that, The method of prevention and control using the fungal composition as described in claim 1 includes the following steps: The fungal composition is applied for the first time during the potato planting period, for the second time during the potato tuber formation period, and for the third time during the potato tuber enlargement period.

4. The method as described in claim 3, characterized in that, During the first, second, and third applications, the chemical control agent and the compound fungicide for potato scab were applied separately.

5. The method as described in claim 3, characterized in that, The first application was applied by trenching, the second application was applied by spraying, and the third application was applied by spraying.

6. The method as described in claim 3, characterized in that, When the fungal-drug composition is applied for the first time, the application rate of the chemical control agent for potato scab is 150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu. When the fungal-drug composition is applied for the second time, the application rate of the chemical control agent for potato scab is 150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu. When the fungal-drug combination is applied for the third time, the application rate of the chemical control agent for potato scab is 150 mL / mu, and the application rate of the compound fungal agent is 5000 mL / mu.

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