Application of quinine derivative in prevention and control of agricultural pathogenic bacteria

Abstract

The invention discloses application of a quinine derivative in prevention and treatment of agricultural pathogenic bacteria, and relates to the technical field of medicinal chemistry. A biological activity test shows that the quinine derivative has a significant effect on plant pathogenic bacteria such as Xanthomonas oryzae pv. Oryzae, Xanthomonas citri pv. Citri and tomato bacterial wilt, and plant pathogenic fungi such as rhizoctonia solani, sclerotinia sclerotiorum, botrytis cinerea, magnaporthe oryzae, fusarium pseudograminearum and fusarium graminearum. And the compound shows certain inhibitory activity on decay-causing pathogenic fungi such as aspergillus flavus, penicillium expansum and brown rot of stone fruits, and has a relatively good inhibitory effect on pathogenic bacteria of rice bacterial blight and rice blast bacteria. The compound is low in preparation difficulty, raw materials are cheap and easy to obtain, and the compound is expected to be developed into a novel agricultural antibacterial agent.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical chemistry, and more particularly to the use of a quinine derivative in the control of agricultural pathogens. Background Technology

[0002] Plant pathogens pose a serious threat to agricultural production, leading to reduced crop yields or even crop failure, and affecting food security. Common pathogens, such as fungi, bacteria, and viruses, infect plant tissues, disrupting their physiological functions and causing diseases. While long-term use of chemical pesticides can effectively control diseases, it can lead to pesticide resistance in pathogens, reducing the effectiveness of control measures.

[0003] Natural products are an important source of new drug development, and their structural diversity and biological activity provide rich templates for drug design. Quinine, a natural alkaloid extracted from cinchona bark, was historically used to treat malaria, demonstrating the enormous potential of natural products in drug development. Optimizing the structure of quinine, such as by introducing specific functional groups or modifying the core skeleton, can enhance its pharmacological activity, improve pharmacokinetic properties, and reduce toxicity. This structural optimization strategy has become an important tool in modern medicinal chemistry, laying the foundation for developing safer and more effective new drugs.

[0004] Quinine Therefore, we modified the structure of quinine to obtain a series of quinine derivatives and tested their anti-plant pathogen activity. The results showed that these compounds exhibited certain inhibitory activity against agricultural bacteria such as *Bacillus oryzae* and agricultural fungi such as *Magnaporthe oryzae*, with superior inhibitory effects against *Bacillus oryzae* and *Magnaporthe oryzae*, significantly better than the control drugs tebuconazole, thiabendazole, and isoprothiolane. Therefore, these compounds hold promise for development into novel anti-plant pathogen drugs. Summary of the Invention

[0005] To address the above shortcomings, this invention provides a use of a quinine derivative in the control of agricultural pathogens. This quinine derivative can be used to control agricultural diseases caused by rice bacterial blight, citrus canker, tomato bacterial wilt, Rhizoctonia solani (rice sheath blight), Sclerotinia sclerotiorum (sclerotinia rot), Botrytis cinerea, Fusarium graminearum (wheat scab), rice blast fungus, Fusarium pseudograminearum (wheat stem rot), Aspergillus flavus, Penicillium expansum, and brown rot of stone fruits.

[0006] The specific technical solution is as follows: The use of a quinine derivative in the control of agricultural pathogens.

[0007] Preferably, the molecular structure of the quinine derivative is shown below: .

[0008] Preferably, the agricultural pathogens include plant pathogenic bacteria and plant pathogenic fungi; the dosage concentration of the quinine derivative for plant pathogenic bacteria is 100, 50, 25, 12.5, 6.25, and 3.12 μg / mL; and the dosage concentration for plant pathogenic fungi and rot-causing fungi is 50, 25, 10, 5, 2.5, and 1 μg / mL.

[0009] Preferably, the plant pathogenic bacteria include one or more of the following: rice bacterial blight pathogen, citrus canker pathogen, and tomato bacterial wilt pathogen.

[0010] Preferably, the plant pathogenic fungi include one or more of the following: Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Rice blast fungus, Fusarium graminearum, Fusarium graminearum, Aspergillus flavus, Penicillium expansum, and brown rot of stone fruits.

[0011] The present invention also provides an agricultural antibacterial agent containing the above-mentioned quinine derivative.

[0012] Preferably, the antimicrobial agent further includes adjuvants and / or agronomically acceptable carriers.

[0013] Preferably, the dosage form of the antibacterial agent includes soluble concentrates, water-dispersible granules, suspension concentrates, wettable powders, oil suspensions, granules, or emulsifiable concentrates.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The quinine derivatives provided by this invention can prevent and control agricultural diseases caused by *Rhizoctonia solani*, *Citrus canker*, *Rhizoctonia solani*, *Rhizoctonia solani* (rice sheath blight), *Sclerotinia sclerotiorum* (sclerotinia rot), *Botrytis cinerea*, *Fusarium graminearum* (wheat scab), *Rhizoctonia solani*, *Fusarium pseudograss* (wheat stem rot), *Aspergillus flavus*, *Penicillium expansum*, and brown rot of stone fruits. It is particularly suitable for inhibiting the pathogens of *Rhizoctonia solani*, *Rhizoctonia solani*, *Citrus canker*, and *Rhizoctonia solani*. Furthermore, the quinine derivatives of this invention are easy to prepare, and the raw materials are inexpensive and readily available, making them a promising candidate for development as a novel agricultural antibacterial agent. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0016] Example 1: Preparation of quinine derivatives Quinine derivatives were synthesized using methods reported in the literature. Pure products were obtained by repeated silica gel column chromatography and other conventional methods. The structures of the quinine derivatives (Kb1~Kb6) were determined by mass spectrometry and nuclear magnetic resonance (NMR) techniques. (Antimicrob Agents Chemother. 58.2(2013):820-827.; J. Med. Chem.) . There are 16 species, including 2019, 62, 5, 2305–2332) and Kc1–Kc10 (ACS Med. Chem. Lett. 2024, 15, 822–827; Org. Lett., Vol. 15, No. 6, 2013), with the specific chemical structures shown below: Example 2: Activity test of quinine derivatives against agricultural pathogenic bacteria 1) Test reagents: Quinine derivatives Kb1~Kc10 prepared in Example 1.

[0017] 2) Test strain: Rice bacterial blight pathogen ( Xanthomonas oryzae ACCC 11602) was provided by Guizhou University; the pathogen of citrus canker ( Xanthomonas axonopodis pv. Citri Provided by Xi'an Nongshim; Tomato bacterial wilt pathogen ( Pseudomonas sollamacearum ( Smith ) Smith Provided by Guangxi Tianyuan.

[0018] 3) Antibacterial activity test: The bacterial strains used in this experiment were cryopreserved in the laboratory at -80℃ with 30% glycerol. The cryopreserved strains were removed and streaked onto NA solid medium (beef extract: 3 g, peptone: 5 g, yeast extract: 1 g, sucrose: 10 g, agar: 15 g, distilled water: 1 L, pH 7.0; sterilized at 121℃ for 20 min), and incubated at 28℃ until single colonies appeared. Single colonies from the solid medium were transferred to NB liquid medium (beef extract: 3 g, peptone: 5 g, yeast extract: 1 g, sucrose: 10 g, distilled water: 1 L; sterilized at 121℃ for 20 min), and cultured on a shaker at 28℃ and 180 rpm until the logarithmic growth phase. The strains in the logarithmic growth phase were diluted with NB liquid medium to approximately 10... 6 CFU / mL was prepared for use. The compounds were dissolved separately in DMSO, added to liquid culture medium, and mixed thoroughly to prepare a drug-containing liquid culture medium with a concentration of 200 μg / mL. 50 μL of the drug-containing culture medium and the same volume of approximately 10... 6CFU / mL bacterial culture was added to the wells of a 96-well plate, resulting in a final drug concentration of 100 μg / mL. A control of 100 μL of bacterial culture containing an equal amount of DMSO was used. The 96-well plates were incubated at 28℃ for 24–48 h until bacterial growth was observed in the control group. The OD value (OD) of the bacterial culture in each well was measured using a microplate reader. 600 In addition, the OD values ​​of 100 μL of liquid culture medium and a 100 μg / mL drug concentration were measured to correct for the OD values ​​caused by the culture medium and the drug itself. The formulas for calculating the corrected OD value and inhibition rate are as follows: Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture medium; Inhibition rate = (OD value of bacterial suspension in control medium after correction - OD value of bacterial suspension in drug-containing medium after correction) / OD value of bacterial suspension in control medium after correction × 100% The drug-containing liquid culture medium was diluted in 96-well plates using a two-fold dilution method to obtain a series of 50 μL drug-containing media of various concentrations. Then, the inhibition rate corresponding to the series of concentrations was determined according to the same experimental method described above. All experiments were performed in triplicate, and the MIC values ​​(the lowest drug concentration that inhibits 90% bacterial growth) of the compound were determined. The results are shown in Table 1.

[0019] Table 1. MIC (μg / mL) of quinine derivatives Kb1~Kc10 against plant pathogenic bacteria in vitro. As shown in Table 1, the quinine derivatives Kb1~Kc10 prepared in this invention exhibited different degrees of inhibitory activity against three plant pathogenic bacteria. Among them, compound Kc10 showed excellent antibacterial activity against rice bacterial blight, citrus canker, and tomato bacterial wilt, with MIC values ​​of 1.56, 6.25, and 3.12 μg / mL, respectively.

[0020] Example 3: Activity test of quinine derivatives against plant pathogenic fungi 1) Test reagents: Quinine derivatives Kb1~Kc10 prepared in Example 1.

[0021] 2) Test strains: Rhizoctonia solani, Sclerotinias clerotiorum, Botrytis cinerea Pers., and Pyricularia oryae Cav. were provided by Gansu Academy of Agricultural Sciences; Fusarium pseudograminearum was provided by Jiangsu Academy of Agricultural Sciences; FusaHum graminearum Sehw. was provided by Beijing Academy of Agricultural Sciences; Aspergillus flavus ACCC 32601, Penicillium expansum ACCC 30898, and Monilinia fructicola ACCC 36263 were obtained from the China Agricultural Microbiological Culture Collection Center.

[0022] 3) Antibacterial activity test: Test Method: Antibacterial activity was determined using potato dextrose agar (PDA) medium. The preparation method is as follows: Wash and peel potatoes, weigh 200g, cut into small pieces, and boil until tender (boil for 20-30 minutes, until the potato pieces can be pierced with a glass rod). Filter through eight layers of gauze, heat, add 15g of agar, continue heating and stirring until dissolved. After the agar is completely dissolved, add glucose, stir well, cool slightly, and then add water to 1000ml. Dispense into Erlenmeyer flasks, stopper and seal, and sterilize at 115℃ for 2 hours. Dissolve the test reagents separately in DMSO, add to the medium, mix well, and ensure the compound concentration in the medium is 50μg / mL. Use an equal concentration of DMSO as a blank control and the marketed drug azoxystrobin as a positive control. Pour plates, cool, inoculate with bacteria, and incubate at 23℃. The inhibition rate of each compound is determined when the mycelium of the blank control completely covers the petri dish. All experiments were conducted in triplicate or in three replicates. The inhibition rate was calculated using the following formula: Antibacterial rate = 100% The inhibition rates of quinine derivatives Kb1~Kc10 against plant pathogenic fungi are shown in Tables 2 and 3: Table 2. Inhibition rate (%) of quinine derivatives Kb1~Kc10 against plant pathogenic fungi at 50 μg / mL. Note: "-" indicates that antibacterial activity was not measured. Table 3. Inhibition rate (%) of quinine derivatives Kb1~Kc10 against putrefactive fungi at 50 μg / mL As shown in Tables 2 and 3, the quinine derivatives Kb1-Kc10 prepared in this invention exhibited varying degrees of inhibitory activity against six plant pathogenic fungi and three molds. Among them, the Kc series compounds showed significantly better inhibitory activity against rice blast fungus than against other pathogens. Therefore, further activity tests were conducted on compounds that showed an inhibition rate greater than 80.00% against plant pathogenic fungi at 50 μg / mL, yielding EC... 50 The test data for the half-maximal effective concentration (WMC) are shown in Table 4.

[0023] Table 4. EC50 of quinine derivatives Kc1~Kc10 against plant pathogenic fungi 50 Value (μg / mL) As shown in Table 4, among the quinine derivatives Kc1~Kc10 prepared in this invention, compound Kc1 exhibits the best inhibitory activity against rice blast fungus. 50 The concentration reached 2.56 μg / mL, comparable to the positive control drug isoprothiolane. These quinine derivatives are readily available and easy to synthesize. Some compounds exhibit higher antibacterial activity than the control drugs tebuconazole and thiamethoxam, making them worthy of further research and potentially promising development into novel agricultural antibacterial agents.

[0024] Example of bactericide preparation: Preparation Example 1: 20% Compound Kc1 Suspension Compound Kc1 20%, alkylphenol formaldehyde resin polyoxyethylene ether 6.3% (emulsifier), sodium methylene bisnaphthalene sulfonate 2.6% (wetting agent), lignosulfonate 1.6% (dispersant), ethylene glycol 2%, xanthan gum 0.1% (thickener), magnesium aluminum silicate 0.3% (thickener), Kathon 0.1% (preservative), organosilicon 0.5% (defoamer), water to 100%.

[0025] The preparation method of the suspension pesticide is as follows: the above raw materials are subjected to high-speed shearing in proportion, and then added to a sand mill for grinding for 2-3 hours to obtain the suspension pesticide formulation.

[0026] Preparation Example 2: 35% Compound Kc2 Suspension Compound Kc2 35%, high molecular weight polycarboxylate 4.4% (dispersant), alkyl naphthalene sulfonate 2.3% (wetting agent), lignin sulfonate 2% (dispersant), glycerol 2%, xanthan gum 0.5% (thickener), Kathon 0.1% (preservative), organosilicon 0.5% (defoamer), water to 100%.

[0027] The preparation method of the suspension pesticide is as follows: the above raw materials are subjected to high-speed shearing in proportion, and then added to a sand mill for grinding for 2-3 hours to obtain the suspension pesticide formulation.

[0028] Preparation Example 3: 40% Compound Kc7 Water Dispersible Granules Compound Kc7 40%, high molecular weight polycarboxylate 7% (dispersant), lignin sulfonate 1% (dispersant), sodium methylene bisnaphthalene sulfonate 5% (wetting agent), polyvinylpyrrolidone 2% (binder), sodium chloride 2% (disintegrant), silica 5% (filler), and kaolin to make up to 100% (filler).

[0029] The preparation method of the water-dispersible granule pesticide is as follows: the above raw materials are mixed evenly in proportion, then added to an air jet mill for pulverization, then granulated and sieved to obtain the water-dispersible granule pesticide formulation.

[0030] Preparation Example 4: 30% Compound Kc4 Soluble Compound Kc4 30%, tristyrene-phenylphenol polyoxyethylene ether 5.7% (emulsifier), calcium dodecylbenzenesulfonate 3% (emulsifier), dimethylformamide 20% (solvent), S-200# solvent oil to make up to 100% (filler).

[0031] The preparation method of the soluble pesticide is as follows: the above raw materials are mixed and stirred evenly in proportion to obtain a transparent and uniform soluble pesticide formulation.

[0032] Preparation Example 5: 30% Compound Kc10 Suspension Compound Kc10 30%, high molecular weight polycarboxylate 4.4% (dispersant), EO / PO block polyether 1.8% (wetting agent), lignosulfonate 3% (dispersant), ethylene glycol 2%, magnesium aluminum silicate 0.5% (thickener), organosilicon 0.5% (defoamer), water to 100%.

[0033] The preparation method of the suspension pesticide is as follows: the above raw materials are subjected to high-speed shearing in proportion, and then added to a sand mill for grinding for 2-3 hours to obtain the suspension pesticide formulation.

[0034] Preparation Example 6: 40% Compound Kc9 Wettable Powder Compound Kc9 40%, high molecular weight polycarboxylate 6% (dispersant), sodium methylene bisnaphthalene sulfonate 3% (wetting agent), silica 5% (filler), diatomaceous earth to make up to 100% (filler).

[0035] The preparation method of the wettable powder pesticide is as follows: the above raw materials are mixed evenly in proportion, and then added to an air jet mill for pulverization to obtain a wettable powder pesticide.

[0036] Preparation Example 7: 25% Compound Kc5 Dispersible Oil Suspension Compound Kc5 25%, castor oil polyoxyethylene ether 4% (emulsifier), block polyether 3.7% (dispersant), alkylphenol formaldehyde resin polyoxyethylene ether 2% (emulsifier), silica 0.5% (thickener), methyl oleate to 100% (filler).

[0037] Preparation method: The preparation method of the dispersible oil suspension pesticide is as follows: compound Kc5 is added to a sand mill and ground with components such as dispersant, emulsifier, thickener, and filler to obtain compound Kc5 dispersible oil suspension; Preparation Example 8: 50% Kb2 water-dispersible granules Compound Kb2 50%, high molecular weight polycarboxylate 7% (dispersant), lignin sulfonate 1% (dispersant), alkyl naphthalene sulfonate 1% (wetting agent), stretching powder 1.5% (wetting agent), soluble starch 2% (binder), urea 2% (disintegrant), bentonite to make up to 100% (filler).

[0038] The preparation method is the same as in Preparation Example 3.

[0039] Preparation Example 9: 10% Compound Kb3 Emulsifiable Oil Compound Kb3 10%, alkylaryl polyoxyethylene polyoxypropylene ether 5.4% (emulsifier), calcium dodecylbenzenesulfonate 2.6% (emulsifier), dimethylformamide 6% (solvent), S-200# solvent oil to make up to 100% (filler).

[0040] Preparation method: Mix solvent and emulsifier, then dissolve compound Kb3, add filler and stir evenly to obtain a transparent emulsifiable liquid formulation.

[0041] Preparation Example 10: 1% Compound Kb4 Granules Compound Kb4 1%, lignin sulfonate 3% (dispersant), alkyl naphthalene sulfonate 3.6% (wetting agent), separating powder 1.4% (wetting agent), polyvinyl alcohol 2% (binder), urea 1% (disintegrant), kaolin to make up to 100% (filler).

[0042] Preparation method: Mix the above raw materials evenly according to the proportion, then add them to an air jet mill for pulverization, and then granulate them to obtain granulated pesticide formulation.

[0043] I. Field efficacy trial for controlling citrus canker Test reagents: The bactericides prepared in Preparation Examples 5 to 9 were respectively 30% Kc10 suspension concentrate, 40% Kc9 wettable powder, 25% Kc5 dispersible oil suspension concentrate, 50% Kb2 water dispersible granules, and 10% Kb3 emulsifiable concentrate.

[0044] Control agent: 20% thiabendazole copper suspension, registration certificate PD20086024, Zhejiang Longwan Chemical Co., Ltd., purchased from the market.

[0045] Blank control: Water Experimental site conditions and citrus varieties: The experimental site is located in Long'an County, Baise City, Guangxi Province. The soil fertility is average, and the terrain is low. The tested variety is Wogan mandarin orange, with a tree age of 5 years and good growth.

[0046] Experimental Design and Methods: Application of pesticides was carried out during the spring shoot stage, focusing on the leaves and ensuring thorough spraying on both the upper and lower surfaces. The experiment consisted of 10 treatment plots, each randomly assigned to a block design. Each plot contained 15 Wogan mandarin orange trees, with three replicates. A conventional electric sprayer (16 kg capacity) was used. The dosage of each pesticide is shown in Table 3. Two applications were made on February 23rd and March 3rd, 2024, during which the weather was mostly cloudy or overcast. The control group (water) received no pesticide treatment for canker.

[0047] Investigation Methods: Observe and record the occurrence of leaf canker 7-10 days after each spraying. Investigate the control efficacy 10 days after the last spraying and record relevant data. Use the diagonal sampling method, with 5 fixed-point surveys, one citrus tree at each point. For each tree, samples are taken from the east, south, west, north, and center. Two branches are surveyed at each point, and four leaves are surveyed from each branch, for a total of 40 leaves. Record the number of diseased leaves at each level.

[0048] The severity of citrus canker is classified according to the number of lesions on a single leaf, and the grading standards are as follows: Level 0: No disease; Grade 1: 1-5 lesions per leaf; Grade 3: 6-10 lesions per leaf; Grade 5: 11-15 lesions per leaf; Grade 7: 16-20 lesions per leaf; Grade 9: More than 21 lesions per leaf.

[0049] Calculate the disease index and relative efficacy using the following formulas: Disease index (%) = [∑(number of diseased leaves at each level × representative value at each level) / (total number of leaves surveyed × highest representative value)] × 100.

[0050] Relative efficacy (%) = (Disease index after treatment in the control area - Disease index after treatment in the treatment area) / Disease index after treatment in the control area × 100. Results are shown in Table 5. Table 5 Results of field efficacy trials for controlling citrus canker As shown in Table 5 above, when the dosage of the preparation is less than that of the control agent 20% thiabendazole copper suspension, the relative efficacy of the fungicides prepared in Examples 5 to 9, namely 30% compound Kc10 suspension, against citrus canker is 13.34%-19.58% higher than that of the control agent.

[0051] II. Field efficacy trials for controlling rice blast The bactericides prepared in Preparation Examples 1 to 4 are 20% Kc1 suspension concentrate, 35% Kc2 suspension concentrate, 40% Kc7 water-dispersible granules, and 30% Kc4 soluble concentrate. The control agent was 30% isoprothiolane emulsifiable concentrate, registration certificate number PD; 20098075, produced by Guangxi Tianyuan Biochemical Co., Ltd. Blank control: Water.

[0052] Experimental Design: The experiment consisted of 6 treatments, with each treatment replicated 4 times, for a total of 24 plots, each plot covering an area of ​​approximately 20m². 2 Each community and the experimental field are protected by four separate lines.

[0053] Application time and method: Begin spraying at the initial stage of rice leaf blast, spraying once every 7 days, for a total of 2 applications. The first application was on July 18, 2024, and the second on July 25. Use a backpack manual sprayer and the standard method of spraying, diluting the pesticide with 40 kg of water per acre according to the dosage in the table.

[0054] Investigation Methods and Grading Standards: A survey was conducted 14 days after the last spraying. A diagonal five-point sampling method was used, with 10 plants surveyed at each point. For each plant, the flag leaf and the two leaves below it were examined. The total number of clumps, total number of plants, total number of diseased leaves per plant (three leaves), and disease grade were recorded. Grading Standards: Level 0: No disease; Grade 1: Fewer than 5 leaf lesions, each less than 1 cm in length; Grade 3: Fewer than 6-10 leaf spots, some of which are longer than 1 cm; Level 5: Fewer than 11-25 leaf spots, some of which merge into patches, covering 10%-25% of the leaf area; Level 7: Fewer than 26 leaf spots, which merge into patches, covering 26%-50% of the leaf area; Level 9: The lesions merge into large patches, covering more than 50% of the leaf area or causing complete leaf death.

[0055] Calculate the disease index and relative efficacy using the following formulas: Disease index (%) = [∑(number of diseased leaves at each level × representative value at each level) / (total number of leaves surveyed × highest representative value)] × 100.

[0056] Relative efficacy (%) = (Disease index after treatment in the control area - Disease index after treatment in the treatment area) / Disease index after treatment in the control area × 100. Results are shown in Table 6. Table 6. Results of field efficacy trials for controlling rice blast. As shown in Table 6 above, when the dosage of the formulation is less than that of the control agent 20% thiabendazole copper suspension, the relative efficacy of the fungicides prepared in Examples 1-4, namely 20% compound Kc1 suspension, in controlling rice blast is 9.95%-17.16% higher than that of the control agent.

[0057] In summary, the quinine derivatives Kb1~Kc10 of this invention, as demonstrated by bioactivity tests, exhibit certain inhibitory activity against three plant pathogenic bacteria (rice bacterial blight, citrus canker, and tomato bacterial wilt), six plant pathogenic fungi (Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Rice blast fungus, Fusarium graminearum, and Fusarium graminearum), and rot-causing fungi such as Aspergillus flavus, Penicillium expansum, and brown rot of stone fruits. Among these, they show particularly good inhibitory effects against rice bacterial blight and Rice blast fungus. The compounds involved in this invention are easy to prepare, use inexpensive and readily available raw materials, and hold promise for development into a novel agricultural antibacterial agent.

[0058] 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. The use of a quinine derivative in the control of agricultural pathogens.

2. The use of a quinine derivative in the control of agricultural pathogens according to claim 1, characterized in that, The molecular structure of the quinine derivative is shown below: 。 3. The use of a quinine derivative in the control of agricultural pathogens according to claim 1, characterized in that, The agricultural pathogens include plant pathogenic bacteria and plant pathogenic fungi.

4. The use of a quinine derivative according to claim 3 in the control of agricultural pathogens, characterized in that, The plant pathogenic bacteria include one or more of the following: rice bacterial blight pathogen, citrus canker pathogen, and tomato bacterial wilt pathogen.

5. The use of a quinine derivative according to claim 3 in the control of agricultural pathogens, characterized in that, The plant pathogenic fungi include one or more of the following: Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Rice blast fungus, Fusarium graminearum, Fusarium graminearum, Aspergillus flavus, Penicillium expansum, and brown rot of stone fruit.

6. An agricultural antibacterial agent, characterized in that, The antibacterial agent contains a quinine derivative as described in claim 1 or 2.

7. An agricultural antibacterial agent according to claim 6, characterized in that, The antimicrobial agent also includes adjuvants and / or agronomically acceptable carriers.

8. An agricultural antibacterial agent according to claim 6, characterized in that, The dosage forms of the antibacterial agents include soluble concentrates, water-dispersible granules, suspension concentrates, wettable powders, oil suspensions, granules, or emulsifiable concentrates.

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