CN114868772A

CN114868772A - Application of Tibetan chrysanthemum indicum extract as bacteriostatic agent

Info

Publication number: CN114868772A
Application number: CN202210532408.8A
Authority: CN
Inventors: 韩彩霞; 邵伟; 张弛; 邵华; 梅宇; 周世兴; 石凯; 陈宏阳
Original assignee: Xinjiang Institute of Ecology and Geography of CAS
Current assignee: Xinjiang Institute of Ecology and Geography of CAS
Priority date: 2022-05-10
Filing date: 2022-05-10
Publication date: 2022-08-09
Anticipated expiration: 2042-05-10
Also published as: CN114868772B

Abstract

Experiments show that the Tibetan Asia chrysanthemum volatile oil extracted by the invention has obvious influence on the growth of bacterial colonies of bacillus subtilis and escherichia coli and fungal hyphae of aspergillus niger and verticillium dahliae under the fumigation culture with extremely low concentration of 5 mug/mL, and the diameter of a bacteriostasis ring is increased along with the increase of the concentration; in a contact experiment, the Tibetan Asia chrysanthemum is the volatile oil which can obviously inhibit the reproduction of bacillus subtilis and escherichia coli cells and aspergillus niger and verticillium dahliae fungal spores under the concentration of 2.5 mg/mL; when the concentration reaches 10mg/mL, the bacterial cells and the fungal spores completely lose the reproductive capacity, which fully indicates that the Tibetan chrysanthemum essential oil has stronger bactericidal power. The Tibetan chrysanthemum volatile oil is a natural plant secondary metabolite, can be quickly decomposed in the nature, is pollution-free, is beneficial to environmental protection, has the potential of being developed into a biological bactericide, and can be applied to the prevention and treatment of organic agricultural pathogenic bacteria.

Description

Application of Tibetan chrysanthemum indicum extract as bacteriostatic agent

Technical Field

The invention belongs to the technical field of plant protection, and relates to an application of a Tibetan chrysanthemum extract as a bacteriostatic agent.

Background

The artificially synthesized chemical bacteriostatic agent is easy to be preserved in nature for a long time, thereby causing the problems of environmental pollution and residual phytotoxicity, and being not in line with the development of sustainable agriculture. The natural bacteriostatic compound extracted from nature has incomparable advantages of synthetic bacteriostatic agent such as easy biodegradation, no residue, low toxicity, low development cost and the like, and the research of the compound is increasingly paid attention by people.

The natural products with rich varieties, different configurations and various action mechanisms in the nature provide possibility for the natural products. In agricultural production, damage caused by pests and diseases is serious, and once the pests and diseases appear, the quality of crops is reduced, and the yield of the crops is influenced. For this reason, in actual agricultural planting, plant diseases cause huge losses to agriculture, and thus crops all over the world are reduced in yield by about 500Mt per year on average. Such as verticillium dahliae, which is the main disease of cotton verticillium wilt, has a wide host range, and can be reported abroad to kill 660 plants of 38 families, wherein 184 crops and 153 weeds. According to the identification of China, at least 20 host plants are 80, and field crops comprise sunflower, eggplant, peppers, tomatoes, tobacco, potatoes, melons, watermelons, cucumbers, peanuts, kidney beans, mung beans, soybeans, sesame, beet and the like. Aspergillus niger is widely distributed in grains, vegetal products and soil all over the world and is a common pathogenic bacterium of fruits such as grapes, sweet persimmons and jujubes. In recent years, food safety events caused by pathogenic microorganisms and bacterial toxins frequently occur and constitute serious threats to human health, for example, Escherichia coli is a conditional pathogen and can cause gastrointestinal tract infection or urinary tract infection and other local tissue and organs of people and various animals under certain conditions, and each year, the occurrence of Escherichia coli-related diseases directly or indirectly causes great economic loss to the breeding industry. Therefore, in daily life and production of people, a natural and effective bacteriostatic agent is urgently needed.

Disclosure of Invention

In view of the above, the present invention aims to provide a new use of a tibetan chrysanthemum extract, which can be used for preparing a bacteriostatic agent.

In order to achieve the purpose, the invention provides the following technical scheme:

1. application of Tibet chrysanthemum extract in preparing bacteriostatic agent is provided.

Further, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the Tibetan chamomile extract is Tibetan chamomile volatile oil. The Tibetan chrysanthemum morifolium volatile oil can be obtained from the overground part of a Tibetan chrysanthemum morifolium plant by a conventional method steam distillation method, and can also be extracted by other volatile oil preparation methods, and the volatile oil component of the Tibetan chrysanthemum morifolium volatile oil naturally exists in the Tibetan chrysanthemum morifolium plant and can be decomposed in the nature, so that the Tibetan chrysanthemum morifolium volatile oil does not pollute the environment.

Further, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the preparation method of the Tibetan chamomile extract comprises the following steps: collecting aerial parts of Tibet chrysanthemum, drying in the shade, crushing, extracting volatile oil by steam distillation, and collecting volatile oil floating on water surface. In the extracted Tibetan chrysanthemum morifolium volatile oil, the main chemical components comprise camphor, 5-methyl-2- (1-methylvinyl) -4-hexen-1-ol, eucalyptol, beta-eucalyptol, (-) -4-terpineol, lavender acetate, bisabolol, alpha-pinene and the like through the analysis of a gas chromatography-mass spectrometer (GC-MS).

Further, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the bacteriostatic agent can respectively inhibit the growth and the propagation of bacteria and fungi, and specifically inhibit bacillus subtilis, escherichia coli, aspergillus niger and/or verticillium dahliae.

Further, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the bacteriostatic agent also comprises an emulsifier.

Further, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the emulsifier is an acetone aqueous solution.

The concentration of the acetone aqueous solution was 0.5% (v/v).

Furthermore, in the application of the Tibetan chamomile extract in preparing the bacteriostatic agent, the Tibetan chamomile extract can be used as a common bactericide; it can also be formulated into different concentrations or mixed with other pesticides, such as dissolving Tibet chrysanthemum extract with 0.5% acetone water solution, diluting to concentration of 2.5-10mg/mL, and spraying or fumigating bacteria (Bacillus subtilis, Escherichia coli) and fungi (Aspergillus niger, Verticillium dahliae).

2. The application of a preparation containing Tibet chrysanthemum extract in the prevention and treatment of organic agricultural pathogenic bacteria.

The invention has the beneficial effects that:

1. the Tibetan chrysanthemum volatile oil provided by the invention can obviously influence the growth of bacteria such as bacillus subtilis and escherichia coli bacterial colonies and fungi such as aspergillus niger and verticillium dahliae fungi hyphae under the fumigation culture with very low concentration of 5 mu g/mL, the diameter of an inhibition zone is increased along with the increase of the concentration, and the growth inhibition effect on the four bacteria is gradually enhanced along with the increase of the concentration.

2. In a spraying contact experiment, the Tibetan inferior chrysanthemum volatile oil provided by the invention can obviously inhibit the propagation of spores of bacillus subtilis, escherichia coli, aspergillus niger and verticillium dahliae fungi at the concentration of 2.5 mg/mL; when the concentration reaches 10mg/mL, the bacterial colony and the fungal spore completely lose the growth and reproduction capacity.

3. Experimental data fully prove that the Tibetan chrysanthemum morifolium volatile oil is suitable for preventing and killing pathogenic bacteria in farmland and common pathogenic bacteria in life of people, the essential oil component is a natural product, the Tibetan chrysanthemum morifolium volatile oil is obtained from overground parts of Tibetan chrysanthemum morifolium plants by a conventional method steam distillation method, the preparation method is simple, the volatile oil component naturally exists in the Tibetan chrysanthemum morifolium plants and can be decomposed in the nature, and therefore, the environment cannot be polluted.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a chromatogram of total ion flux (TIC) of extracted volatile oil components of Tibet chrysanthemum.

FIG. 2 is a measurement of the diameter of the zone of inhibition of the fumigating effect of the Tibet chrysanthemum volatile oil on the bacterial colonies of Bacillus subtilis, Escherichia coli, Aspergillus niger and Verticillium dahliae;

FIG. 3 is a graph of the bacteriostatic circle of Tibetan Matricaria volatile oil on Bacillus subtilis and Escherichia coli bacteria.

FIG. 4 is a graph showing the inhibition zones of Tibet chrysanthemum volatile oil on Aspergillus niger and Verticillium dahliae colonies.

FIG. 5 is a graph of data showing the effect of Tibet Matricaria volatile oil on the contact culture of Bacillus subtilis, Escherichia coli bacteria, Aspergillus niger and Verticillium dahliae.

FIG. 6 is a bar graph of data for root length and shoot length of Tibet Matricaria volatile oil on the effect of Poa pratensis and alfalfa as weeds.

FIG. 7 shows the effect of Tibet Matricaria volatile oil on killing aphids on cotton.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The experimental procedures, in which specific conditions are not specified in the examples, are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

Example 1

The method comprises collecting wild Tibet chrysanthemum plant in indoor shade, cutting aerial parts with pruning shears, placing into volatile oil distillation extractor, distilling for 4 hr by conventional steam distillation method to obtain volatile oil floating on water surface, and storing at 4 deg.C under sealed condition for volatile oil activity determination. On average, the yield of the Tibetan Matricaria recutita volatile oil is 0.01mL/g (v/w, namely 0.01mL of volatile oil is produced per gram of the dry matter of the aboveground part of Tibetan Matricaria recutita).

Analyzing the obtained Tibetan Matricaria volatile oil by a gas chromatography-mass spectrometer (GC-MS) to obtain the components and the Total Ion Chromatogram (TIC) of the components provided in the table 1, wherein the total ion chromatogram is shown in the figure 1. As can be seen from Table 1, the volatile oil of Tibet chrysanthemum extracted by the invention contains 49 chemical components, which account for 96.00% of the total volatile oil components, wherein the main chemical components with higher content comprise camphor (29.76%), 5-methyl-2- (1-methylethenyl) -4-hexen-1-ol (13.23%), eucalyptol (12.07%), beta-eucalyptol (6.93%), (-) -4-terpineol (5.70%), lavender acetate (4.00%), bisabolol (2.43%), alpha-pinene (2.11%), and the like.

Table 1 major chemical composition of volatile oil of Tibet Chamomilla

Example 2

Fumigating effect of Tibet Matricaria volatile oil on Bacillus subtilis, Escherichia coli, Aspergillus niger and Verticillium dahliae:

wherein the bacillus subtilis (CICC 21897), the Escherichia coli (CICC 10305) and the Aspergillus niger (CICC 41255) are purchased from China center for culture Collection of industrial microorganisms (http:// m.china-cic.org); the Verticillium dahliae strain is deciduous strong pathogenic strain V991, which is preserved by Xinjiang institute of ecology and geography of Chinese academy of sciences.

The method comprises the following steps: selecting a glass culture dish with the diameter of 9cm, pouring 20mL of LB (for culturing bacillus subtilis and escherichia coli) or PDA culture medium (for culturing aspergillus niger and verticillium dahliae), solidifying the culture medium,respectively mixing 100 μ L of 1 × 10 ⁶ Spreading bacterial cell or fungal spore solution of above CFU/mL on the bottom of culture dish under aseptic condition, then pasting sterilized 5mm filter paper sheets on the culture dish, pasting 4 filter paper sheets on each culture dish, wherein volatile oil is dripped into 3 filter paper sheets, and 0.5% acetone aqueous solution is dripped into the rest filter paper sheets as blank control; the concentrations of the volatile oil on the filter paper sheets are respectively 5, 10, 20 and 40 mug/mL (except 0.5% acetone aqueous solution, aqueous solutions such as Tween 20 and Tween 80 can be used as emulsifiers), the culture dish is sealed by a sealing film, bacteria are cultured at 35 ℃, fungi are cultured at 28 ℃, the size of a bacteriostatic circle is observed after 48 hours, the diameter of the bacteriostatic circle is measured (the diameter of the filter paper sheet is not measured), and Table 2 shows the diameter measurement value of the bacteriostatic circle of the fumigating colony of the Tibetan chamomile essential oil on bacillus subtilis, Escherichia coli, Aspergillus niger and Verticillium dahliae.

Table 2 diameter (mm) of 3 replicate zone of inhibition measurements per concentration:

"-" indicates no measurement.

FIG. 2 shows the variation of the diameter measurement value of the inhibition zone of the volatile oil of Tibet chrysanthemum on the fumigation effect of the bacterial colonies of Bacillus subtilis, Escherichia coli, Aspergillus niger and Verticillium dahliae with the concentration, and as can be seen from FIG. 2, the growth of the bacterial colonies of Bacillus subtilis and Escherichia coli and the hyphae of fungi of Aspergillus niger and Verticillium dahliae is obviously affected under the fumigation culture of the volatile oil of Tibet chrysanthemum at a low concentration of 5 mug/mL, the diameter of the inhibition zone increases with the increase of the concentration, and the specific effects are shown in the culture diagrams of FIG. 3 and FIG. 4.

Example 3

Effect of the Tibetan Matricaria volatile oil on contact culture of Bacillus subtilis, Escherichia coli bacteria, Aspergillus niger and Verticillium dahliae:

the method comprises the following steps: dissolving Tibet chrysanthemum volatile oil with 0.5% acetone water solution, and preparing 20mg/mL (1 mL 0.5% acetone water solution added with 20mg Tibet chrysanthemum)Volatile oil), 200 μ L was added to the 1 st well of a 96-well plate; then taking 100 mu L of the mixture from the 1 st hole, putting the mixture into the 2 nd hole, adding 100 mu L of 0.5% acetone aqueous solution, and uniformly mixing; taking 100 mu L of the mixture from the 2 nd hole, putting the mixture into the 3 rd hole, adding 100 mu L of 0.5% acetone aqueous solution, and uniformly mixing; then taking 100 mu L of the mixture from the 3 rd hole, putting the mixture into the 4 th hole, adding 100 mu L of 0.5% acetone aqueous solution, and uniformly mixing; repeating the steps until 100 mu L of volatile oil solution in the 5 th hole is taken out and put into the 6 th hole, adding 100 mu L of 0.5% acetone aqueous solution, uniformly mixing, taking 100 mu L of volatile oil solution in the 6 th hole out and abandoning; so that the content of the volatile oil in each hole is reduced by times. Well 7 was used as a control to which 100. mu.L of 0.5% aqueous acetone was added. Finally, 100. mu.L of 1X 10 solution was added to each well ⁶ CFU/mL bacterial liquid or fungal spore solution is mixed with the volatile oil solution uniformly, and finally 200 mu L of cell/or spore and volatile oil mixed liquid is contained in each hole, and the concentration of the Tibetan chrysanthemum volatile oil in 7 holes is 10, 5, 2.5, 1.25, 0.625, 0.3125 and 0mg/mL in sequence; at each concentration of 3 replicates, bacteria were incubated at 35 ℃ and fungi at 28 ℃ after 48h, the OD of the culture was measured at an absorbance of 600nm using a microplate reader (Leiende LD-96A). Table 3 shows the OD values at 600nm of 3 replicates per concentration.

The data statistical method comprises the following steps: and (4) detecting whether the difference among the groups of data is significant (p is less than 0.05) by using one-way anova, and obtaining the average value and the standard deviation.

TABLE 3 OD value at 600nm of 3 replicates per concentration

As a result: under the concentration of 2.5mg/mL of the Tibetan Asiatic chrysanthemum volatile oil, the propagation of bacillus subtilis and escherichia coli cells and aspergillus niger and verticillium dahliae fungal spores is obviously inhibited; when the concentration reached 10mg/mL, the bacterial colonies and fungal spores were completely incapacitated, and the effect is shown in fig. 5.

The Tibetan chrysanthemum volatile oil can be used as a bacteriostatic agent, and tests show that: the Tibetan Asiatic chrysanthemum volatile oil has obvious influence on the growth of bacterial colonies of bacillus subtilis and escherichia coli and hypha of aspergillus niger and verticillium dahliae fungi under the fumigation culture with low concentration of 5 mu g/mL, and the diameter of a bacteriostasis zone is increased along with the increase of the concentration; in a contact experiment, the Tibetan Asiatic chrysanthemum volatile oil obviously inhibits the reproduction of bacillus subtilis and escherichia coli cells and aspergillus niger and verticillium dahliae fungal spores at the concentration of 2.5 mg/mL; when the concentration reaches 10mg/mL, the bacterial cells and fungal spores completely lose fertility. The volatile oil of Tibet chrysanthemum is extracted from aerial parts of Tibet chrysanthemum plant, is a natural component, can be rapidly decomposed in nature, does not pollute environment, is beneficial to environmental protection, and can be applied to control and remove pathogenic bacteria of organic crops and common pathogenic bacteria in daily life of people.

Example 4

Effect of the volatile oil of Tibet Matricaria on the growth of seedlings of the weed Poa annua and alfalfa:

dissolving Tibet chrysanthemum volatile oil by using 0.5% acetone aqueous solution, sequentially preparing volatile oil suspension with the concentration of 0.25, 0.5, 1, 2 and 5mg/mL, placing filter paper in a culture dish with the diameter of 9cm by using 0.5% acetone aqueous solution as blank Control (CK), respectively transferring 3mL of volatile oil suspension with different concentrations into the culture dish, placing 30 seeds of a kind of Poa pratensis and alfalfa in each culture dish, repeating the steps for 3 times in each concentration, sealing by using a sealing film, placing the culture dish in an incubator at the temperature of 25 ℃ for 5 days, and measuring the seedling height and the root length of 60 seedlings (the root length and the seedling height length of ungerminated seeds are marked as '0'); table 4 shows the measured values of the root length and the seedling height of seedlings of Poa annua, and Table 5 shows the measured values of the root length and the seedling height of seedlings of alfalfa.

The data statistical method comprises the following steps: firstly, detecting whether the difference among groups of data is significant by using one-factor variance analysis, then analyzing the data by using an LSD (least squares decomposition) method, wherein the difference among the groups with different marked letters is significant, and the level p is less than 0.05;

TABLE 4 measurement values (cm) of root length and seedling height of Poa pratensis seedlings

TABLE 5 measurement of alfalfa seedling root length and seedling height (cm)

The data bar chart of the root length and seedling length of the grass and alfalfa is shown in fig. 6, and the results in fig. 6 show that: under the low concentration action of 0.5mg/mL Tibet chrysanthemum volatile oil, the growth of seedlings of wild weeds such as bluegrass and alfalfa is obviously inhibited, the growth inhibition action is gradually enhanced along with the increase of the concentration, when the concentration reaches 1mg/mL, the inhibition rates of the root length of the bluegrass and alfalfa are 86.89% and 60.71%, and the inhibition rates of the seedling height are 93.72% and 62.09% respectively; when the concentration reaches 2mg/mL, the inhibition rates on the root length of the bluegrass and the alfalfa are respectively 100 percent and 85.12 percent, and the inhibition rates on the seedling are respectively 100 percent and 89.33 percent; when the concentration is increased to 5mg/mL, the seeds of the bluegrass and the alfalfa are all killed.

Example 5

The Tibetan Asiatic chrysanthemum volatile oil has a poisoning effect on cotton aphids:

the cotton aphid (Aphis gossypii Glover) is an insect of the genus Aphidae, commonly known as the putrefaction. Is a worldwide pest of cotton. The cotton aphids in cotton field in southern Xinjiang area, 2008,45(4): 670-. Because Aphis gossypii is absolutely predominant in quantity, it is harmful and can cause leaf rolling of cotton, thus arresting the growth of cotton.

The method comprises the following steps: pasting a filter paper sheet with the diameter of 5mm in the upper cover of a glass culture dish, wherein the diameter of the culture dish is 9cm (the volume of the culture dish is 100mL), and respectively dripping 0.5, 1, 2, 4, 8 and 10mg of volatile oil of the Tibetan chrysanthemum on the filter paper sheet to ensure that the concentration of the volatile oil of the Tibetan chrysanthemum in the culture dish is 5, 10, 20, 40, 80 and 100 mu g/mL, and each concentration is 3 times; and laying a layer of filter paper on the bottom cover of the culture dish, placing healthy leaves of the field collected black nightshade plants, placing 30 cotton aphids on each black nightshade leaf of the culture dish, placing the black nightshade leaves at room temperature for 24 hours, calculating the survival number of the cotton aphids, and calculating the lethality rate of the volatile oil to the cotton aphids, wherein the specific data are shown in table 6.

Table 6 number of surviving cotton aphids and mortality:

FIG. 7 shows the effect of Tibet chrysanthemum volatile oil on aphid poisoning, and the data in FIG. 7 shows that the average value of the number of cotton aphids surviving in each concentration repeat test is 23.67, 20.33, 15.33, 7 and 3 at concentrations of 5, 10, 20, 40 and 80 μ g/mL; the lethality to cotton aphids is 21.11%, 32.22%, 48.89%, 76.67% and 90.00% in sequence; when the concentration reaches 100 mug/mL, the cotton aphid is completely poisoned. The semilethal concentration LC50 of the Tibet chrysanthemum volatile oil on cotton aphid is 17.41 mu g/mL, and the effect is shown in figure 7.

The Tibetan chrysanthemum volatile oil can be used as an herbicide and an insecticide, and the experiments show that: when the concentration of the Tibetan Asia chrysanthemum volatile oil is 0.5mg/mL, the Tibetan Asia chrysanthemum volatile oil can obviously inhibit the growth of seedlings of wild weeds such as the bluegrass and the alfalfa, and when the concentration reaches 1mg/mL, the inhibition rates of the roots and the seedlings of the bluegrass and the alfalfa are both more than 50%; when the concentration was increased to 5mg/mL, the seeds of Poa annua and alfalfa were all killed. When the concentration of the Tibetan Asia chrysanthemum volatile oil is 80 mug/mL, the lethality rate to cotton aphids reaches 90.00 percent in sequence; when the concentration reaches 100 mug/mL, the cotton aphid is completely poisoned. The Tibetan Asia chrysanthemum volatile oil is extracted from the overground part of Tibetan Asia chrysanthemum plant, the extraction method is simple, the effective components are all natural components, the Tibetan Asia chrysanthemum volatile oil can be quickly decomposed in the nature, the environment is not polluted, and the method is favorable for environmental protection. The herbicide can be independently prepared into use concentrations and then used as common herbicides and insecticides, or can be used as an additive component to be mixed with other pesticides for weed control and/or pest control in organic agriculture. For example, after dissolving with 0.5% acetone/water (v/v) solution, spraying at a concentration of 2mg/mL or more before and after emergence of weeds; or diluting to obtain volatile oil with concentration of 100 μ g/mL or above 100 μ g/mL, and spraying to insect damage on leaf surface.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

2. The use of Tibet chrysanthemum extract for preparing bacteriostatic agent according to claim 1, wherein the Tibet chrysanthemum extract is volatile oil of Tibet chrysanthemum.

3. The use of the Tibet chrysanthemum extract according to claim 2 for preparing bacteriostatic agent, wherein the Tibet chrysanthemum extract is prepared by the following steps: collecting aerial parts of Tibet chrysanthemum, drying in the shade, crushing, extracting volatile oil by steam distillation, and collecting volatile oil floating on water surface.

4. Use of an extract of Tibet inula in the preparation of a bacteriostatic agent according to claim 1, wherein the bacteriostatic agent is specifically against Bacillus subtilis, Escherichia coli, Aspergillus niger and/or Verticillium dahliae.

5. The use of an extract of Tibet chrysanthemum as claimed in claim 1, wherein the bacteriostatic agent further comprises an emulsifier.

6. The use of an extract of Tibet chrysanthemum as claimed in claim 5, wherein the emulsifier is an aqueous solution of acetone.

7. The use of the Tibet chrysanthemum extract according to claim 5 in the preparation of a bacteriostatic agent, wherein the Tibet chrysanthemum extract is dissolved in 0.5% acetone aqueous solution, diluted to a concentration of 2.5-10mg/mL, and subjected to spraying contact or fumigation treatment on Bacillus subtilis, Escherichia coli, Aspergillus niger and Verticillium dahliae.

8. The application of a preparation containing Tibet chrysanthemum extract in the prevention and treatment of organic agricultural pathogenic bacteria.