Application of nepetalactone mint or volatile matter thereof in preparation of antibacterial composition

Abstract

The invention relates to the technical field of biopesticides, in particular to application of nepetalactone mint or volatile matter thereof in preparation of a bacteriostatic composition. Compared with other chemical types of mint volatile matters, the nepetalactone type mint volatile matter provided by the invention can be used as an effective plant-source synergist of an existing antibacterial agent for preventing and treating fusarium. The invention further provides an antibacterial composition which is prepared by compounding the volatile matter of the schizonepeta lactone type mint with three antibacterial agents (including thiophanate-methyl, metalaxyl-M and pyraclostrobin), and the antibacterial composition has a synergistic effect; by adding volatile matters of the schizonepeta lactone type mint into the antibacterial agent or intercropping the schizonepeta lactone type mint, the purposes of reducing application and increasing efficiency are achieved, the cost is effectively controlled, ecological cultivation is facilitated, and the method is suitable for popularization and application.

Description

Technical Field

[0001] This invention relates to the field of biopesticide technology, specifically to the application of nepeta lactone-type peppermint or its volatile components in the preparation of antibacterial compositions. Background Technology

[0002] Fusarium is an important filamentous fungus group among agricultural pathogens. *Fusarium oxysporum* (also known as *Fusarium oxysporum*), as one of the soil-borne plant pathogens, has become the most common plant pathogen in the genus since its discovery in 1917. It mainly invades host plants through wounds on young roots and the base of stems, parasitizing vascular tissues and producing toxins, causing yellowing and wilting of leaves, shriveling and necrosis of stems, ultimately leading to root rot, stem rot, and vascular wilt in various economic crops, inducing more than 150 plant diseases. Currently, fungicides targeting plant pathogens worldwide can be divided into two main categories: systemic and non-systemic fungicides, with main components including tebuconazole, spiroxamine, cyprodinil, and fludioxonil. Azole fungicides are controversial due to their potential to pollute surface water, groundwater, and drinking water, and their harm to aquatic animals, thus being considered environmental pollutants. In vivo studies have confirmed that azole fungicides are hepatotoxic to mammals and are not ideal fungicides. Furthermore, impurities are unavoidable in the artificial synthesis of compounds. Even with purification processes, obtaining 100% pure synthetic compounds is virtually impossible; achieving 99.9% purity requires a significant increase in purification costs, which is impractical for pesticide manufacturers. Therefore, my country's pesticide quality standards only require a purity of 90% or higher for technical grade pesticides. Impurities in technical grade pesticides often lead to crop damage, enhance pesticide toxicity, and may even cause harm to humans, including teratogenic and carcinogenic effects, as well as environmental damage. Simultaneously, long-term application of single-component or simply compounded fungicides for field disease control easily leads to drug resistance in pathogens, forcing farmers to continuously increase pesticide dosages, posing a significant threat and damage to the environment, livestock, aquatic life, and the entire ecosystem. These problems are even more pronounced for plants with special medicinal properties that require concentrated application, including traditional Chinese medicinal herbs.

[0003] Plant volatiles are a class of small-molecule secondary metabolites produced from the flowers, leaves, stems, and roots of aromatic plants. Their main components are terpenoids, and they are gaining attention as a safe alternative to synthetic pesticides due to their antibacterial and bactericidal activities. Among them, the volatile oils of several plants in the Lamiaceae family, such as *Dracocephalum moldavica* L., *Origanum vulgare* L., *Thymbra Spicata* L., and *Rosmarinus officinalis* L., have been shown to have inhibitory activity against plant pathogens such as *Fusarium oxysporum*.

[0004] Although current research has repeatedly confirmed the antifungal activity of plant volatile oils, their high cost makes them unsuitable for direct use as agricultural fungicides. According to market analysis of technical grade pesticides provided by Zhongnong Lihua, the end-market demand for triazole products is high, with active trading and prices rising year by year. For example, the current price of tebuconazole technical grade is only 52,000 yuan / ton, and metalaxyl technical grade is 92,000 yuan / ton. Meanwhile, the current price of conventional peppermint oil is approximately 1,080 yuan / kg, or 1.08 million yuan / ton, which is not a cost that current agricultural production can afford. Therefore, directly using volatile oils to replace existing pesticides is impractical. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide the application of nepeta lactone-type peppermint or its volatiles in the preparation of antibacterial compositions. The present invention provides a compound antibacterial agent composed of nepeta lactone-type peppermint volatiles and three commonly used antibacterial agents. Under the compound, each reagent can synergistically enhance the effect, which can significantly reduce the amount of pesticides used while ensuring the prevention effect in daily agricultural activities, effectively reduce the cost of pesticide use, and promote the development of agricultural ecology.

[0006] This invention provides the use of nepeta lactone-type peppermint or its volatiles in enhancing the antibacterial activity of antibacterial agents and / or in preparing formulations that enhance the antibacterial activity of antibacterial agents.

[0007] In some embodiments, the antibacterial agent includes at least one of thiophanate-methyl, metalaxyl, and pyraclostrobin;

[0008] The antibacterial effect includes inhibiting Fusarium, which includes Fusarium oxysporum and / or Fusarium solanum.

[0009] The present invention provides an antibacterial composition comprising volatiles of nepeta lactone-type peppermint and an antibacterial agent in a volume ratio of (1~20):(0.5~5);

[0010] The antibacterial agent includes at least one of thiophanate-methyl, metalaxyl, and pyraclostrobin.

[0011] The experiments of this invention demonstrate that not all peppermint oils with good in vitro antibacterial activity exhibit synergistic effects with existing bactericides; in fact, many even show antagonistic effects. Compared to the volatiles of other chemically derived peppermint, the volatiles of nepetalactone-type peppermint provided by this invention, when combined with the aforementioned antibacterial agents, exhibit synergistic effects. This significantly reduces the dosage of antibacterial agents while effectively inhibiting the activity of Fusarium, thereby achieving precise technical results.

[0012] In some embodiments, the method for preparing the volatiles of nepeta lactone-type peppermint includes:

[0013] Take tender branches of nepeta lactone-type peppermint and distilled water at a mass-to-volume ratio of 1 g: (0.5~5) mL in a round-bottom flask, and distill by water distillation for 5~10 hours to obtain the volatiles of the nepeta lactone-type peppermint.

[0014] In some embodiments, the tender shoots of the nepeta lactone type mint are obtained by collecting clean, dew-free, and unwatered tender shoots within 20 cm of the tip of the nepeta lactone type mint at 9:00 AM on sunny days that last for more than 3 consecutive days, using a five-point sampling method, and cutting them into small sections of about 3 cm in length.

[0015] In some embodiments, the tender branches of the nepeta lactone-type peppermint are mixed with distilled water at a mass-to-volume ratio of 1 g: 1 mL.

[0016] The distillation time is 5 hours.

[0017] In some specific embodiments, the volatiles of the nepetalactone-type peppermint include nepetalactone, d-limonene, 3-hexen-1-ol, α-thujone, α-pinene, sapinene, 3-carene, β-pinene, β-myrcene, isoterpinene, γ-terpinene, α-terpineol, hydrated sapinene, isopropenyltoluene, linalool, 3-octanol, acetate, isopropylcyclohexanone, geranyl vinyl ether, l-menthone, terpinene-4-ol, p-cymene-8-ol, (-)-dihydrofrucin II, (Z)-hydrated sesquiterpinene, methyl cinnamaldehyde, 8,9-dehydrothymol, longleaf menthone, trans-carvone, linaloyl butyrate, cis-oxycarvone, epoxidized humulene II, isoperenone, 2,5-dimethylhydroquinone, and peppermint. At least one of the following: ketone, (-)-methylhemothrinone, hydroquinone, hemothrin-8-ol, piperonone, piperanol, (-)-β-boronene, β-elemene, guarjuolone, (-)-α-guarene, caryophyllene, sennaol, β-cobaene, bicyclosesquiphylene, humulene, β-acorol, ylang-ylangene, caryophyllene oxide, geraniol D, juniperene, acorene, and 1-epi-coubeol.

[0018] In some embodiments, the volatiles of the nepetalactone-type peppermint include 35% to 40% nepetalactone and 28% to 32% d-limonene.

[0019] In some specific embodiments, the volatiles of the nepetalactone-type peppermint include 38.64% nepetalactone and 29.32% d-limonene.

[0020] In some embodiments, it comprises volatiles of nepeta lactone-type peppermint and an antibacterial agent in a volume ratio of 10:1.

[0021] In some embodiments, the antibacterial agent is metalaxyl.

[0022] This invention provides the application of the aforementioned antibacterial composition in the prevention and control of plant diseases caused by Fusarium.

[0023] In some embodiments, the Fusarium includes Fusarium oxysporum and / or Fusarium solanum.

[0024] This invention provides a method for controlling plant diseases caused by Fusarium, wherein the antibacterial composition is applied to the diseased plants.

[0025] Compared with the volatiles of other chemically derived peppermint, the volatiles of nepetalactone-type peppermint provided by this invention can serve as an effective plant-derived synergist for current antibacterial agents in controlling Fusarium. This invention further provides antibacterial compositions in which the volatiles of nepetalactone-type peppermint are compounded with three antibacterial agents (including thiophanate-methyl, metalaxyl, and pyraclostrobin). These antibacterial compositions synergistically enhance efficacy. By adding the volatiles of nepetalactone-type peppermint to the antibacterial agents or intercropping with nepetalactone-type peppermint, the goal of reducing application and increasing efficacy can be achieved. This effectively controls costs and contributes to ecological cultivation, making it suitable for widespread application. Attached Figure Description

[0026] Figure 1 The study showed the differences in the inhibitory activity of volatiles from different genera of the Lamiaceae family against Fusarium solani.

[0027] Figure 2 Chromatograms of volatile oils from six species of the genus *Mentha* are shown. In Figure A, 1-menthone-type *Mentha* is shown; in Figure B, linalool-type *Mentha* is shown; in Figure C, nepetalactone-type *Mentha* is shown; in Figure D, piperonone-type *Mentha* is shown; in Figure E, d-limonene-type *Mentha* is shown; and in Figure F, longleaf menthol-type *Mentha* is shown.

[0028] Figure 3 The study showed that six peppermint volatile oils at a concentration of 0.50 mL / L inhibited the mycelial growth of Fusarium solani after 7 days of incubation at 28℃.

[0029] Figure 4The effects of three chemical peppermint oils combined with different fungicides on the mycelial growth of Fusarium after 7 days of incubation at 28℃ are shown. The left figure shows the results of Fusarium oxysporum vanilla-specific type, and the right figure shows the results of Fusarium solani. Detailed Implementation

[0030] This invention provides the application of nepeta lactone-type peppermint or its volatiles in the preparation of antibacterial compositions. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0031] *Mentha* is a genus of aromatic perennial or rarely annual herbs belonging to the Lamiaceae family. Due to polymorphism and interspecific hybridization, the exact number of species in this genus is uncertain, with approximately 30 species recorded, of which about 12 are currently well-established in my country. The volatile oils extracted from *Mentha* plants have been repeatedly proven to have good inhibitory activity against bacterial food poisoning, animal and plant pathogens, and human pathogens. The *Pharmacopoeia of the People's Republic of China* explicitly designates *Mentha haplocalyx* Briq. (later revised to *Mentha canadensis* L.), a native species of the genus *Mentha* in the Lamiaceae family, as a medicinal species.

[0032] Peppermint oil has been found to have antibacterial activity against *F. proliferatum*. Besides the native species *Mentha*, the volatile oils of other members of the same genus, such as *Mentha spicata* L. and *M. longifolia* (L.) Hudson, have also been shown to have inhibitory activity against *Fusarium oxysporum*. However, peppermint oil is expensive, costing approximately 10 times more than the technical grade of triazole fungicides currently on the market. Directly using volatile oil to replace existing pesticides is impractical, and whether it has synergistic or antagonistic effects on pesticides is still unknown, thus lacking practical application value in production.

[0033] This invention collects volatile oils from four plant genera (Rosmarinus, Lavender, Mentha, and Ocimum) of the Lamiaceae family using steam distillation. Using *Fusarium solani-melongenae* as the test strain, in vitro antibacterial tests were conducted to screen for the most effective plant genus, namely *Mentha*. Six different chemotypes were then selected for volatile oil collection, and their volatile components were identified using GC-MS. *Fusarium solani-melongenae* was used as the test strain to determine the differences in antibacterial activity of different chemotypes of peppermint oil against *Fusarium*. *Fusarium oxysporum* f. sp. vanillaecc and *Fusarium solani-melongenae* were used as test strains, respectively, with concentrations of 0.01... Using mL / L pyraclostrobin, thiophanate-methyl, and metalaxyl as controls, this study evaluated the synergistic effect of the volatile metabolites of this chemical-type plant on the tested active ingredients. It was found that the volatile metabolites of nepeta lactone-type peppermint have a synergistic effect with current pesticides in controlling Fusarium wilt, and that intercropping this chemical-type peppermint can effectively achieve the goal of reducing pesticide application and increasing efficacy.

[0034] The test materials used in this invention are all commercially available products. The invention will be further illustrated below with reference to specific embodiments.

[0035] Example 1

[0036] 1. Materials

[0037] 1.1 Plant Materials All Lamiaceae plants used in the test were conserved in the Aromatic Medicinal Plant Resource Nursery of the Subtropical Agriculture Research Institute of Fujian Academy of Agricultural Sciences. They were grown in a pollution-free manner to ensure no pesticide residues.

[0038] 1.2 The tested pathogens, *Fusarium oxysporum* vanilla-specific strain (GenBank: PX362823.1), were isolated from vanilla plants infected with stem rot; *Fusarium solani* strain (GenBank: PX352975.1) was isolated from passion fruit plants infected with stem base rot. All the above strains were inoculated into disease-free host plants according to Koch's rule to confirm that the tested pathogens had significant pathogenicity, and were preserved in the Plant Pathology Laboratory of the Subtropical Agriculture Research Institute of Fujian Academy of Agricultural Sciences.

[0039] 1.3 Test culture medium Potato glucose agar medium (PDA): 200 g potato, 20 g glucose, 20 g agar, and deionized water to a final volume of 1000 mL.

[0040] 1.4 Experimental Instruments and Chemical Reagents: Volatile oil analyzer (density < 1.0), spherical condenser, round-bottom flask and other glassware, Zhangzhou Tengxin Chemical Glassware Instrument Co., Ltd.; XB. K. 25 hemocytometer, Shanghai Qiujing Biochemical Reagent Instrument Co., Ltd.; Heating mantle, Gongyi Yuhua Instrument Co., Ltd.; Basic-Q15-IT pure water system, Shanghai Hetai Instrument Co., Ltd.; GF54DA vertical automatic pressure steam sterilizer, Zhiwei (Xiamen) Instrument Co., Ltd.; MJ-250 constant temperature light incubator, Shanghai Yiheng Scientific Instrument Co., Ltd.; SW-CJ-1F clean bench, Suzhou Antai Air Technology Co., Ltd. (Suzhou Jingjing Group); Trace 1300 / TSQ9000 gas chromatograph-mass spectrometer, Thermo Fisher Scientific (USA). Scientific Inc.; Dimethyl sulfoxide (DMSO) molecular biology grade, Sangon Biotech (Shanghai) Co., Ltd.; Thiophanate-methyl, Metalaxyl-M, Pyraclostrobin (≥98.0%) analytical standards, Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0041] 2 Methods

[0042] 2.1 Extraction and Determination of Volatile Oil Content of Test Plants The volatile oils used in this invention were extracted and their content determined according to the volatile oil determination method in the Chinese Pharmacopoeia, with slight modifications. Test samples were collected at 9:00 AM on sunny days with at least three consecutive days of sunshine. Clean, dew-free, and unwatered tender shoots within 20 cm of the tip were collected using a five-point sampling method. The shoots were cut into approximately 3 cm long segments and placed in 1000 mL hard-bottom flasks, 200 g per flask. 200 mL of water was added, and the mixture was shaken and connected to the volatile oil analyzer and reflux condenser. Distilled water was added from the top of the condenser until it filled the graduated section of the volatile oil analyzer and overflowed into the flask. The flask was placed in a heating mantle and slowly heated until the liquid surface in the flask reached a boil. A gentle boil was maintained for 5 hours. After stopping heating for 1 hour, the volume of volatile oil was read and collected in a brown reagent bottle, sealed, and stored at below 26 °C for later use.

[0043] 2.2 Determination of volatile oil chemical components, peppermint oil content, by gas chromatography-mass spectrometry (GC-MS). The gas chromatography method was slightly modified to use headspace sampling and GC-MS component analysis.

[0044] Gas chromatography conditions: Thermo TG-5SilMS GC polar column (30 m length, 0.25 mm inner diameter, 0.25 μm film thickness); injection port temperature: 250 ℃; detector temperature: 250 ℃; injection volume: 1.0 μL, split ratio 1:100; carrier gas: nitrogen. Temperature program: initial temperature 60 ℃, hold for 4 min, increase to 100 ℃ at a rate of 2 ℃ / min, then increase to 230 ℃ at a rate of 10 ℃ / min, hold for 1 min.

[0045] Mass spectrometry conditions: EI ionization mode; EI ion source temperature: 210 ℃; transfer line temperature: 250 ℃; electron multiplication voltage: 1847 V; ionization voltage: 70 eV; ion source temperature: 300 ℃; scan mass range (m / z): 30-550. Chemical components were determined through library retrieval and data analysis, combined with manual spectral interpretation from literature. The relative content of each component was calculated using peak area normalization based on the average peak area of ​​each chromatographic peak according to the total ion current, with two significant figures retained.

[0046] 2.3 Screening and MIC determination of antibacterial activity of volatile oils: The mycelial growth inhibition method was used to determine the antibacterial activity of the tested volatile oils. The method was slightly modified and divided into four stages.

[0047] In the first stage, *Fusarium solani* was used as the test strain. Under aseptic conditions, 25 μL of the test volatile oils of rosemary, lavender, peppermint, and basil were added to Erlenmeyer flasks, respectively. The flasks were then diluted to 50 mL with sterile, thawed PDA medium to prepare drug-containing medium with a concentration of 0.50 mL / L. The medium was poured into five 90 mm diameter sterile petri dishes to prepare drug-containing plates of the corresponding concentrations. PDA medium without volatile oils was used as a blank control (CK).

[0048] In the second stage, *Fusarium solani* was used as the test strain. GC-MS was used to identify the main components of the volatile oil and determine its chemotype. Based on the results of the first stage, one-way ANOVA was performed to screen the test genera with the best antibacterial activity. Six varieties with different chemotypes were selected, and their antibacterial activity was screened according to the method in the first stage. 25 μL of the test volatile oil was added to each Erlenmeyer flask, diluted with DMSO and brought to a final volume of 500 μL. Then, sterile, thawed PDA medium was used to bring the final volume to 50 mL, preparing a 0.50 mL / L drug-containing medium. This medium was poured into five 90 mm diameter sterile petri dishes to prepare the corresponding drug-containing plates. A 0.01 mL / L metalaxyl-M was used as the positive control (+); a PDA medium containing 10 mL / L DMSO was used as the blank control (CK).

[0049] In the third stage, based on the experimental results of the second stage, the EC50 concentration of peppermint oil against Fusarium oxysporum, which was measured by the project team in the early stage, i.e., 0.10 mL / L, was used as the test concentration. Pyraclostrobin, thiophanate-methyl, and metalaxyl were used as control groups, and a formulation containing 0.01 mL / L control reagent + 0.10 mL / L peppermint oil was used as the treatment. The in vitro inhibition rate of different chemical types of peppermint oil against Fusarium solani and Fusarium oxysporum vanilla-specific type was tested. The synergistic effect of the target volatile oil on the tested pesticides was evaluated by Jin Zhengjun's Q-value method (referencing Jin Zhengjun's "Additive Effect in Combined Application of Pesticides" and Dai Tijun's "Quantitative Analysis of Combined Application of Pesticides").

[0050] Kim Jong-kyun's Q-value evaluation formula:

[0051] Q = Ea+b / Ea+Eb-Ea×Eb

[0052] Ea+b: Measured inhibition rate of the two drugs in combination

[0053] Ea, Eb: Inhibition rate when used as a single drug

[0054] Judgment criteria:

[0055] Q<0.85 indicates antagonistic effect.

[0056] 0.85 ≤ Q < 1.15 indicates an additive effect.

[0057] Q≥1.15 indicates synergistic effect

[0058] Preparation of bacterial pellets: Under aseptic conditions, take 200 μL of bacterial suspension with a concentration of 106~107 CFU / mL and spread it evenly on a PDA plate. After incubation at 28℃ for 7 days, use a 4 mm diameter punch to collect bacterial pellets and transfer them to the center of each of the above-mentioned drug-containing and blank PDA culture dishes. Place them in a constant temperature incubator at 28℃ and incubate upright in the dark for 24 h, then invert and incubate in the dark for 6-9 days until the colonies in the blank PDA reach the edge of the culture medium.

[0059] Measurement and data analysis: When the hyphae of the control group approached the edge of the culture dish, the colony diameter (mm) was measured using the cross-sectional method. This was repeated 3 times, and the average value was taken to calculate the inhibition rate. Inhibition rate (%) = (growing diameter of blank control colony - growing diameter of treated colony) / diameter of blank control colony × 100.

[0060] 3. Statistical Analysis

[0061] The mean inhibition rate and standard deviation were calculated using Microsoft Excel, and one-way ANOVA was performed using SPSS V13.0 software.

[0062] 3 Results and Analysis

[0063] 3.1 Antibacterial activity test of volatile oils from different genera

[0064] Depend on Figure 1 As shown in Table 1, the mycelial growth inhibition test revealed that, under the same concentration conditions, the volatiles of the genera *Mentha* and *Rosemary* exhibited significantly better inhibitory activity against *Fusarium* than lavender and basil (p < 0.01). Among them, *Mentha* showed the best inhibitory activity.

[0065] Table 1. Inhibition rates of volatile substances from different genera of Lamiaceae plants against Fusarium solani in vitro.

[0066]

[0067] Note: Uppercase letters indicate highly significant differences (p≤0.01), and lowercase letters indicate significant differences (p<0.05).

[0068] 3.2 Evaluation of the antibacterial activity of different chemical types of peppermint volatile oil

[0069] 3.2.1 Chemical type determination of peppermint oil: Based on GC-MS analysis, the tested peppermint oils can be classified into six types according to the highest content of volatile components: d-limonene type, linalool type, l-menthone type, pulegone type, piperitenone type, and nepetalactone type.

[0070] The mass spectrometry analysis results in Table 2 show that the volatile components of peppermint vary considerably among different chemical types. α-pinene, β-pinene, and d-limonene are common components in peppermint oil from all six chemical types. Other components include sabinene, β-myrcene, terpinolene, α-terpineol, linalool, 3-octyl acetate, L-menthone, and (-)-dihydroedulan. II], pulegone, piperenone, cadinol, (-)-β-bourbonene, β-elemene, (-)-α-gurjunene, caryophyllene, β-copaene, humulene, and muurolene are present in more than four kinds of peppermint volatile oil.

[0071] Table 2. Chemical composition analysis of six peppermint volatile oils

[0072]

[0073]

[0074]

[0075]

[0076] Note: "—" indicates not detected.

[0077] 3.2.2 Screening for antibacterial activity

[0078] like Figure 3 As shown in Table 3, at an effective concentration of 0.01 mL / L, metalaxyl had no antibacterial activity against Fusarium solani. The antibacterial activities of six peppermint volatile oils against Fusarium are as follows: Figure 3 As shown in Table 3, at a volume concentration of 0.50 mL / L, the volatiles of piperonone-type peppermint exhibited the strongest inhibitory activity against Fusarium solani, reaching 83.53%; the volatiles of nepeta lactone-type peppermint were second (78.12%), significantly lower than those of piperonone-type peppermint (p < 0.05), but extremely significantly better than other peppermint varieties (p ≤ 0.01); the volatiles of linalool-type peppermint had the lowest inhibitory activity against Fusarium, at 20.00%, but were still extremely significantly better than those of metalaxyl.

[0079] Table 3. In vitro inhibition rates of six peppermint volatiles against Fusarium solani.

[0080]

[0081] Note: Uppercase letters indicate highly significant differences (p≤0.01), and lowercase letters indicate significant differences (p<0.05).

[0082] 3.3 Evaluation of the synergistic / antagonistic effects of different chemical types of peppermint volatile oil on pesticides

[0083] From Table 4-5 and Figure 4 It is known that peppermint oil with good antibacterial activity does not necessarily have a synergistic effect with all currently used pesticides. Among them, piperonone type has the strongest antibacterial activity against Fusarium, but when combined with conventional fungicides, its synergistic effect against Fusarium is not as significant as that of nepeta lactone type, and it even shows an antagonistic effect on fungicides when used to control Fusarium solani. Longleaf menthone type also often shows additive or antagonistic effects when combined with current fungicides. It is not recommended to use the above two chemical types of peppermint volatiles in the park where the tested pesticides are conventionally sprayed, so as to avoid reducing the control efficacy.

[0084] Although the antibacterial activity of nepeta lactone-type peppermint oil is significantly lower than that of piperonone-type peppermint oil when used alone, it almost always shows good synergistic effects when combined with the three tested fungicides. It is more suitable for field promotion and helps to reduce crop application and increase efficiency, thus achieving green pest control.

[0085] Table 4. Differences in synergistic / antagonistic effects (Q values) of three chemical peppermint oils combined with pesticides for controlling Fusarium oxysporum.

[0086]

[0087] Note: "-" indicates antagonistic effect, " / " indicates additive effect, and "+" indicates synergistic effect.

[0088] Table 5. Differences in synergistic / antagonistic effects (Q values) of three chemical peppermint oils combined with pesticides for controlling Fusarium solani.

[0089]

[0090] Note: "-" indicates antagonistic effect, " / " indicates additive effect, and "+" indicates synergistic effect.

[0091] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of catmint lactone mint or its volatile in enhancing the fungistatic activity of a fungistatic agent and / or in preparing a preparation for enhancing the fungistatic activity of a fungistatic agent.

2. The use according to claim 1, wherein the fungistatic agent comprises at least one of thiophanate-methyl, mefenoxam and pyraclostrobin; and the fungistasis comprises inhibiting Fusarium, including Fusarium oxysporum and / or Fusarium solani.

3. The use according to claim 1 or 2, wherein the volatile of catmint lactone mint comprises a volume ratio of (1-20):(0.5-5) of the volatile of catmint lactone mint to the fungistatic agent.

4. The use according to any one of claims 1-3, wherein the fungistatic agent comprises mefenoxam.

3. A bacteriostatic composition characterized in that, 5. The fungistatic composition according to claim 4, wherein the tender branch of catmint lactone mint and distilled water are in a mass-volume ratio of 1g:1mL; and the distillation time is 5h.

6. The fungistatic composition according to claim 5, wherein the volatile of catmint lactone mint comprises a volume ratio of 10:1 of the volatile of catmint lactone mint to the fungistatic agent.

4. The bacteriostatic composition according to claim 3, characterized in that, 7. The fungistatic composition according to claim 6, wherein the fungistatic agent is mefenoxam.

8. Use of the fungistatic composition according to any one of claims 3-7 in preventing and treating plant diseases caused by Fusarium, including Fusarium oxysporum and / or Fusarium solani.

9. Use of the fungistatic composition according to any one of claims 3-7 in preventing and treating plant diseases caused by Fusarium, including Fusarium oxysporum and / or Fusarium solani, by applying the fungistatic composition to the diseased plants. ​ ​ 6. The bacteriostatic composition according to any one of claims 3 to 5, wherein ​ 7. The bacteriostatic composition according to any one of claims 3 to 6, wherein ​ ​ 9. Use according to claim 8, characterized in that, ​ 10. A method for controlling plant diseases caused by Fusarium species, characterized by, ​

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