Biological pesticide for preventing and treating tobacco bacterial diseases

Abstract

The present application belongs to the technical field of biological pesticides, and particularly relates to a biological pesticide for preventing and treating tobacco bacterial diseases. The active ingredient of the biological pesticide is prepared by compounding shenzimycin and rheochrysidin at a mass ratio of 1-80:80-1. The active ingredient of the biological pesticide is prepared by compounding shenzimycin and tolylfluanid or rheochrysidin. It is found by the filter paper diffusion method that the compounding formula of the biological pesticide has a synergistic effect on tobacco Pseudomonas syringae which causes tobacco wild fire disease, and can improve the prevention and treatment effect on tobacco wild fire disease compared with a single agent.

Description

Technical Field

[0001] This invention belongs to the field of biological pesticide technology, specifically relating to a biological pesticide for the prevention and control of bacterial diseases in tobacco. Background Technology

[0002] Tobacco wildfire is caused by Pseudomonas tobaccosiformis (… pseudomonas syringae pv. tabaci Tobacco wildfire disease is a bacterial disease of tobacco caused by infection. It can occur in both seedbeds and fields, primarily affecting leaves, but can also damage young stems, capsules, and sepals. Initially, small, brown, water-soaked spots appear on leaves, surrounded by a distinct yellow halo. In rainy and humid weather, the lesions expand and enlarge, with several lesions merging to form irregular, large brown spots. In dry weather, the lesions crack and fall off, causing the leaves to crumble. Young stems, capsules, and sepals develop irregular small spots, initially water-soaked, later turning brown with indistinct halos. In rainy and humid weather, affected seedlings rot and collapse, or only the terminal bud remains upright, pale and weak, partially scorched and broken, eventually dying, resembling a wildfire-damaged plant.

[0003] Currently, there are relatively few pesticides on the market for controlling bacterial diseases, and the variety is limited, mainly focusing on copper-based agents and agricultural antibiotics. Furthermore, long-term application of single agents can easily lead to drug resistance in pathogens, environmental pollution, and pesticide residues.

[0004] Shenqinmycin is an antibiotic secreted by *Pseudomonas fluorescens* M18 through biological culture. It is a fungicide with dual effects, possessing broad-spectrum inhibition of plant pathogens and promoting plant growth. It is also a biological pesticide with independent intellectual property rights in my country. Existing technology has been disclosed; shenqinmycin, when combined with copper oxychloride, thiamethoxam, ethoxysulfuron, thiamethoxam, or streptomycin, can control bacterial diseases. However, there are currently no reports of shenqinmycin being combined with mesylate or rhein. Summary of the Invention

[0005] The purpose of this invention is to provide a biological pesticide for controlling tobacco wildfire disease, which can improve the control effect of tobacco wildfire disease, enrich the variety of bactericidal agents, delay the development of pathogenic bacteria resistance to agents, and is of great significance for providing new and efficient agents for controlling bacterial diseases in tobacco production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A biological pesticide for preventing tobacco wildfire disease, wherein the active ingredient of the biological pesticide is a compound of shenqinmycin and mesylate or rhein in a mass ratio of 1-80:80-1.

[0007] Preferably, the mass ratio of shenqinmycin to mesylate is 1-20:8-1.

[0008] Preferably, the mass ratio of shenqinmycin to mesylate is 1:2.

[0009] Preferably, the mass ratio of shenqinmycin to rhein is 1-10:10-1.

[0010] Preferably, the mass ratio of shenqinmycin to rhein is 5:1.

[0011] The present invention also provides the use of the aforementioned biological pesticide in the prevention and control of tobacco wildfire disease.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The active ingredient of the biological pesticide of the present invention is a compound of shenqinmycin and mesylate or rhein. The filter paper diffusion method was used to verify that the compound formulation of the biological pesticide of the present invention has a synergistic effect on Pseudomonas tobacco, which causes tobacco wildfire, and can improve the control effect of tobacco wildfire compared with single agent.

[0013] (2) The biological pesticide of the present invention is a new type of biological pesticide with the characteristics of low toxicity, low residue and low pollution.

[0014] (3) The biological pesticide of the present invention can enrich the variety of bactericidal agents, delay the development of pathogenic bacteria resistance to agents, and provide new and efficient agents for the prevention and control of bacterial diseases in tobacco production, which is of great significance. Detailed Implementation

[0015] The technical solution of this invention patent will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0016] Example Indoor activity test 1. Test pathogens Pseudomonas tobaccoii ( pseudomonas syringae pv. tabaci ), isolated from infected tobacco samples, and preserved in the laboratory.

[0017] 2. Culture medium NA medium: 5g peptone, 3g beef extract, 2.5g glucose, 15g agar powder, add distilled water to a final volume of 1L, natural pH.

[0018] NB medium: 5g peptone, 3g beef extract, 2.5g glucose, add distilled water to a final volume of 1L, natural pH.

[0019] 3. Test reagents 95% Shenqinmycin technical grade (Shanghai Nongle Biological Products Co., Ltd.), 96.5% Mesylatezazole technical grade (Guangxi Tianyuan Biochemical Co., Ltd.), 98% Rhein technical grade (Zhengzhou Huiju Chemical Co., Ltd.).

[0020] After the test reagent is completely dissolved, it is diluted with 0.1% Tween-80 to prepare a single-agent stock solution with a concentration of 10000 mg / L. Then, multiple ratios are set up, and each single-agent stock solution and each mixed reagent are set up with 0.1% Tween-80 in a proportional manner to form 5 series of mass concentration gradients for later use.

[0021] 4. Test Methods Referencing the filter paper diffusion method of Wei Haijuan et al. (2011), the test pathogens were cultured in a NA culture medium at 30℃ for 24 h. Two loops of colonies were picked and placed in 100 mL of NB culture medium, and cultured with shaking at 30℃ and 180 r / min for 24 h. The bacterial suspension concentration was then adjusted to 1.0 × 10⁻⁶ using a hemocytometer. 8 CFU / mL. When the temperature of the sterile NA medium drops to approximately 50°C, pour 10 mL into each 9 cm diameter petri dish, shake well, and allow to cool to form a plate. Spread 50 μL of bacterial suspension evenly onto the cooled NA plate. Punch 5 mm diameter filter paper discs, sterilize them, and immerse them in the drug solution for 1 hour. Remove the discs, drain excess solution, and place them in the center of each bacterial plate, one filter paper disc per plate. Use filter paper discs soaked in 0.1% Tween-80 aqueous solution as a blank control. Each treatment is repeated three times. Incubate at 30°C for 48 hours. Measure the diameter of the inhibition zone using the cross-sectional method and calculate the inhibition rate.

[0022]

[0023] 5. Data Analysis The drug concentration was converted to a logarithmic value, and the corresponding inhibition rate was converted to a probability value. A regression equation for virulence and EC was calculated with the logarithmic concentration as the independent variable and the inhibition rate probability value as the dependent variable. 50 The co-toxicity coefficient (CTC value) of the mixture was calculated according to Sun Yunpei's method. The experimental results are shown in Table 1-2.

[0024] Table 1. Indoor bioactivity assay of the combination of shenqinmycin and mesylate with Pseudomonas aeruginosa. Shenqinmycin 34.0928 100.0000 -- -- Methionazole 14.3427 237.7014 -- -- Shenqinmycin 1: Mesylate 10 15.3004 222.8229 225.1831 98.9519 Shenqinmycin 1: Mesylatezazole 8 11.9553 285.1689 222.4013 128.2227 Shenqinmycin 1: Mesylatezazole 5 7.5717 450.2661 214.7512 209.6688 Shenqinmycin 1: Mesylatezazole 2 2.0031 1702.0019 191.8009 887.3793 Shenqinmycin 1: Mesylatezazole 1 10.1731 335.1270 168.8507 198.4753 Shenqinmycin 2: Mesylatezazole 1 16.7509 203.5282 145.9005 139.4980 Shenqinmycin 5: Mesylatezazole 1 22.6162 150.7450 122.9502 122.6066 Shenqinmycin 10: Mesylate 1 19.7025 173.0379 112.5183 153.7865 Shenqinmycin 20: Mesylate 1 24.1407 141.2254 106.5572 132.5348 Shenqinmycin 25: Mesylatezazole 1 39.1165 87.1571 105.2962 82.7732 Table 1 shows that the co-toxicity coefficient of shenqinmycin and mesylate-based sulfadiazine against *Pseudomonas tobaccois* is greater than 120 within a mass ratio of 1-20:8-1, indicating a synergistic effect; the synergistic effect is most significant when the mass ratio is 1:2. This demonstrates that the formulation of shenqinmycin and mesylate-based sulfadiazine in this invention can improve the control effect against tobacco wildfire disease.

[0025] Table 2. Indoor bioactivity assay of shenqinmycin and rhein combined with Pseudomonas aeruginosa. Shenqinmycin 34.0928 100.0000 -- -- rhein 26.2891 129.6842 -- -- Shenqinmycin 1: Rhein 15 24.3588 139.9609 127.8289 109.4908 Shenqinmycin 1: Rhein 10 18.7229 182.0914 126.9856 143.3953 Shenqinmycin 1: Rhein 5 15.8836 214.6415 124.7368 172.0755 Shenqinmycin 1: Rhein 2 10.1526 335.8036 119.7894 280.3282 Shenqinmycin 1: Rhein 1 18.0632 188.7418 114.8421 164.3489 Shenqinmycin 2: Rhein 1 12.4736 273.3197 109.8947 248.7104 Shenqinmycin 5: Rhein 1 7.8533 434.1207 104.9474 413.6557 Shenqinmycin 10: Rhein 1 16.6465 204.8046 102.6986 199.4231 Shenqinmycin 15: Rhein 1 40.8870 83.3830 101.8553 81.8642 Table 2 shows that the co-toxicity coefficient of shenqinmycin and rhein against *Pseudomonas tobaccoii* is greater than 120 within a mass ratio of 1-10:10-1, indicating a synergistic effect; the synergistic effect is most significant when the mass ratio is 5:1. This demonstrates that the formulation of shenqinmycin and rhein of this invention can improve the control effect against tobacco wildfire disease.

[0026] In summary, the active ingredient of the biopesticide of this invention is a compound of shenqinmycin and mesylate or rhein. Verification by the filter paper diffusion method revealed that the compound formulation of the biopesticide of this invention has a synergistic effect on Pseudomonas tobaccoii, which causes tobacco wildfire. Compared with single agents, it can improve the control effect on tobacco wildfire, enrich the variety of bactericidal agents, delay the development of drug resistance in pathogenic bacteria, and is of great significance for providing new and highly effective agents for the control of bacterial diseases in tobacco production.

[0027] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A biological pesticide for controlling bacterial diseases of tobacco, characterized in that, The active ingredient of the biological pesticide is a compound of shenqinmycin and rhein in a mass ratio of 1-80:80-1.

2. The biological pesticide according to claim 1, characterized in that, The mass ratio of shenqinmycin to rhein is 1-10:10-1.

3. The biological pesticide according to claim 2, characterized in that, The mass ratio of shenqinmycin to rhein is 5:

1.

4. The use of the biological pesticide according to any one of claims 1-3 in the prevention and control of tobacco wildfire disease.