CN113197231B - Pesticide prepared from pure natural plant essential oil, preparation method and application thereof - Google Patents

Abstract

The invention provides a pesticide prepared from pure natural plant essential oil, a preparation method and application thereof, belongs to the field of agricultural technology application, and can solve the technical problems of high research and development cost, single active ingredient, unsatisfactory prevention and treatment effect and the like in the prior art. The pesticide prepared from the pure natural plant essential oil comprises the following components in parts by weight: 5-15 parts of citronella essential oil, 3-5 parts of areca leaf essential oil, 2-5 parts of cinnamomum camphora seed essential oil, 1-2 parts of surfactant and 80-90 parts of water. The invention has the characteristics of natural components, low cost, multiple active components, good prevention and treatment effect and the like. The invention can be applied to the application aspect of botanical pesticides.

Description

A kind of pesticide made from pure natural plant essential oil, preparation method and application thereof

technical field

The invention belongs to the application field of agricultural technology, and in particular relates to a pesticide made from pure natural plant essential oil, a preparation method and application thereof.

Background technique

Botanical pesticides are preparations made from plant roots, stems, leaves, flowers, fruits and other parts or isolated active ingredients. Plant-derived active ingredients are inherent in plants, and bioactive ingredients of different species have different mechanisms of action. For example, some can improve plant disease resistance and achieve the purpose of disease prevention. Compared with chemical pesticides, botanical pesticides have good environmental compatibility and can be decomposed in nature without pollution. Particularity, pests and diseases are not easy to develop resistance after use, which is the development direction of pesticides in the future.

At present, there are two main ways of research and development of botanical pesticides. One is to screen the active ingredients of pesticides in plants, identify the structure of the active substances, find the lead compounds of chemically synthesized pesticides, and carry out structural transformation to explore the structure effect. After obtaining better compounds, semi-synthesis or total synthesis is carried out and developed into innovative drugs; the other is mainly through the screening of pesticide active substances in plants, and the direct application of plant resources to develop botanical pesticides, which is more efficient. It is in line with my country's national conditions of "rich plant resources and less capital", but the above two research and development methods have problems such as high research and development costs, single active ingredients, and unsatisfactory control effects.

Therefore, how to develop a pesticide with natural ingredients, low cost and good control effect is the key to solving the above problems.

SUMMARY OF THE INVENTION

Aiming at the technical problems of the prior art such as high research and development cost, single active ingredient, and unsatisfactory control effect, the present invention proposes a pure natural product with the characteristics of natural ingredients, low cost, multiple active ingredients and good control effect. Pesticides made from plant essential oils.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A pesticide made from pure natural plant essential oil, in parts by weight, comprising the following components:

5-15 parts of citronella essential oil, 3-5 parts of betel leaf essential oil, 2-5 parts of camphor seed essential oil, 1-2 parts of surfactant and 80-90 parts of water.

Preferably, in parts by weight, the following components are included:

5 parts of citronella essential oil, 3 parts of betel leaf essential oil, 2 parts of camphor seed essential oil, 1 part of surfactant, and 90 parts of water.

Preferably, the surfactant includes, but is not limited to, any one or more of Tween 80, Poloxamer or Span 80.

Preferably, the formulation of the pesticide made from pure natural plant essential oil is any one of spray, wettable powder or dispersible oil.

The present invention also provides a kind of preparation method of the pesticide made from pure natural plant essential oil using any of the above-mentioned preferred technical solutions, comprising the following steps:

Weigh dry citronella, betel leaf and camphor seeds, and pulverize to obtain citronella meal, betel leaf meal and camphor seed meal respectively;

Take citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder respectively as raw material, carry out essential oil extraction process, obtain citronella essential oil, betel leaf essential oil and camphor seed essential oil, and calculate the oil rate;

According to the proportion of parts by weight, after mixing the citronella essential oil, betel leaf essential oil and camphor seed essential oil with surfactant and water, the pesticide made from pure natural plant essential oil is prepared.

Preferably, the essential oil extraction method is selected from any one of steam distillation, solvent extraction, CO ₂ supercritical extraction, subcritical water extraction or microwave-assisted extraction, preferably microwave-assisted extraction.

As preferably, the described method for extracting citronella essential oil, betel leaf essential oil and camphor seed essential oil with microwave-assisted extraction method comprises the steps:

Weigh described citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder, and after mixing with water respectively, make citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution;

After the citronella mixed solution, the betel leaf mixed solution and the camphor seed mixed solution are all subjected to microwave-assisted extraction treatment for 15-60 min, the citronella essential oil, the betel leaf essential oil and the camphor seed essential oil are collected, and the oil rate is calculated.

Preferably, the weight ratio of the citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder to water is 1:(20-50), preferably 1:20, and the power of the microwave-assisted extraction treatment is 160-700W, 550W is preferred.

The present invention also provides an application of the pesticide made from the pure natural plant essential oil described in any of the above-mentioned preferred technical solutions, and the pesticide made from the pure natural plant essential oil is used for the prevention and control of Alternaria spp., Plant diseases caused by molds, Aspergillus, Cladosporium, Fusarium, and Terrestrial.

Preferably, the pesticide made from pure natural plant essential oil is used for the prevention and treatment of Pseudomonas spp , Botrytis cinerea, black root disease, fruit rot, rot, fusarium wilt, botrytis cinerea and mildew heart disease; the application objects of the pesticide made from pure natural plant essential oils are guava, banana, tomato, safflower Sorrel, cowpea, privet golden leaf, lentils, lotus root and tripterygium wilfordii.

Compared with the prior art, the advantages and positive effects of the present invention are:

1, the present invention provides a kind of pesticide that is made of pure natural plant essential oil, and this kind of pesticide can be widely used in the prevention and treatment by various organically combining citronella essential oil, betel leaf essential oil and camphor seed essential oil with other auxiliary agents. Among the plant diseases caused by pathogenic bacteria, and achieved good control effect;

2. The present invention provides a method for preparing a pesticide made from pure natural plant essential oil, which has the advantages of simple operation, low cost, and good quality of the extracted essential oil.

Description of drawings

Fig. 1 is three kinds of essential oils provided by the embodiment of the present invention and the pesticide that is made by pure natural plant essential oil to the growth inhibition curve of Pseudomonas guava;

Fig. 2 is three kinds of essential oils provided by the embodiment of the present invention and the pesticide that is made by pure natural plant essential oil to Pseudomonas guava growth inhibition colony diagram;

Fig. 3 is the growth inhibition curve diagram of different concentrations of pesticides provided by the embodiment of the present invention to Pseudomonas guava;

FIG. 4 is a graph showing the results of the antibacterial experiments on three kinds of plant pathogenic bacteria by pesticides of different concentrations provided in the embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The embodiment of the present invention provides a pesticide made from pure natural plant essential oil, which, in parts by weight, comprises the following components:

5-15 parts of citronella essential oil, 3-5 parts of betel leaf essential oil, 2-5 parts of camphor seed essential oil, 1-2 parts of surfactant and 80-90 parts of water.

In the above technical solution, the embodiment of the present invention provides a pesticide made of pure natural plant essential oil, and the active components of the pesticide are citronella essential oil, betel leaf essential oil and camphor seed essential oil, and the embodiment of the present invention selects the above several kinds Essential oils are active ingredients because:

Lemongrass, also known as "lemongrass", is a perennial dense clump-shaped herb with fragrance. It is native to South India and Sri Lanka. Common varieties include: West Indian Lemongrass, East Indian Lemongrass, and the distribution of Lemongrass in my country Very extensive, about 55 varieties. At the same time, because citronella oil contains active ingredients such as geranial and neral, it has the functions of preventing and controlling diseases and insect pests, repelling mosquitoes, anti-oxidation, anti-bacterial and anti-corrosion. Citronella oil from different origins has certain inhibitory effects on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Bacillus typhi, Shigella, Candida albicans, Penicillium citrinum, Aspergillus niger and Pseudomonas;

Betel nut is a kind of palm plant and is a perennial evergreen tree, which is one of the top five southern medicines in China. Betel nut leaves include many beneficial components, nutrients and biologically active components needed by the human body, among which the biologically active components mainly include alkaloids, phenols, amino acids and minerals. A large number of studies have shown that betel leaf has the functions of promoting blood circulation, eliminating insects and sterilizing;

Camphor, a large evergreen tree in the Lauraceae family, is rich in essential oils, and its roots, stems and leaves can be used to extract essential oils, and camphor essential oils usually have a variety of biologically active components, with antibacterial and antioxidant properties. , anti-inflammatory, insecticidal and other effects.

In a preferred embodiment, in parts by weight, the following components are included:

5 parts of citronella essential oil, 3 parts of betel leaf essential oil, 2 parts of camphor seed essential oil, 1 part of surfactant, and 90 parts of water.

In a preferred embodiment, the surfactant includes, but is not limited to, any one or more of Tween 80, Poloxamer or Span 80.

In a preferred embodiment, the dosage form of the pesticide made from pure natural plant essential oil is any one of spray, wettable powder or dispersible oil.

The present invention also provides a kind of preparation method of the pesticide made from pure natural plant essential oil using any of the above-mentioned preferred embodiments, comprising the following steps:

S1, take by weighing dry citronella, betel leaf and camphor seeds, and pulverize to obtain citronella meal, betel leaf meal and camphor seed meal respectively;

S2, take respectively citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder as raw material, carry out essential oil extraction process, obtain citronella essential oil, betel leaf essential oil and camphor seed essential oil, and calculate the oil rate;

S3, according to the parts by weight ratio, after the citronella essential oil, the betel leaf essential oil and the camphor seed essential oil are mixed with surfactant, water, the described pesticide made of pure natural plant essential oil is obtained.

In a preferred embodiment, the method for the extraction and treatment of the essential oil is selected from any one of steam distillation, solvent extraction, _CO supercritical extraction, subcritical water extraction or microwave-assisted extraction, preferably microwave Auxiliary extraction method.

In a preferred embodiment, the described method for extracting citronella essential oil, betel leaf essential oil and camphor seed essential oil with microwave-assisted extraction method comprises the steps:

(1) take by weighing described citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder, and after mixing with water respectively, make citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution;

(2) after described citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution are all carried out to microwave-assisted extraction for 15-60min, collect citronella essential oil, betel leaf essential oil and camphor seed essential oil, and calculate the oil rate.

In a preferred embodiment, the weight ratio of the citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder to water is 1:(20-50), preferably 1:20, and the power of the microwave-assisted extraction treatment is 160-700W, preferably 550W.

The present invention also provides an application of the pesticide made from the pure natural plant essential oil described in any of the above-mentioned preferred embodiments, and the pesticide made from the pure natural plant essential oil is used for the prevention and treatment of Alternaria spp., Plant diseases caused by molds, Aspergillus, Cladosporium, Fusarium, and Terrestrial.

In a preferred embodiment, the pesticides made from pure natural plant essential oils are used to prevent and treat Pseudomonas brown spot disease, blight, gray mold, black spot, root rot, fusarium wilt and fruit rot. , leaf spot, gray mold, black root, fruit rot, rot, fusarium wilt, gray mold and mold heart disease.

In a preferred embodiment, the objects of application of the pesticide made of pure natural plant essential oils are guava, banana, tomato, sorrel, cowpea, privet, lentils, lotus root and tripterygium wilfordii.

In order to introduce the pesticide made from pure natural plant essential oil, the preparation method and the application thereof provided by the embodiments of the present invention more clearly and in detail, the following will be described with reference to specific embodiments.

Example 1

The present embodiment provides a pesticide made from pure natural plant essential oils and a preparation method thereof, specifically:

Formulation: In parts by weight, it includes the following components:

5 parts of citronella essential oil, 3 parts of betel leaf essential oil, 2 parts of camphor seed essential oil, 1 part of Tween 80 and 90 parts of water;

Preparation:

(1) take by weighing dry citronella, betel leaf and camphor seeds, and pulverize to obtain citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder respectively;

(2) take by weighing citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder, and after mixing with water respectively, obtain citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution, wherein, citronella is thick The weight ratio of flour, betel leaf meal and camphor seed meal to water is 1:20;

(3) after described citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution are all carried out to microwave-assisted extraction processing 15min, wherein, the power of microwave-assisted extraction processing is 550W, collects citronella essential oil, betel leaf essential oil and camphor Seed essential oil, and calculate the oil rate;

(4) according to the above-mentioned parts by weight ratio, after the citronella quintessence oil, the betel leaf quintessence oil and the camphor seed quintessence oil are mixed with Tween 80 and water, the described pesticide made from the pure natural plant quintessence oil is obtained.

Example 2

The present embodiment provides a pesticide made from pure natural plant essential oils and a preparation method thereof, specifically:

Formulation: In parts by weight, it includes the following components:

15 parts of citronella essential oil, 5 parts of betel leaf essential oil, 5 parts of camphor seed essential oil, 1 part of Tween 80 and 80 parts of water;

(1) take by weighing dry citronella, betel leaf and camphor seeds, and pulverize to obtain citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder respectively;

(2) take by weighing citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder, and after mixing with water respectively, obtain citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution, wherein, citronella is thick The weight ratio of powder, betel leaf meal and camphor seed meal to water is 1:50;

(3) after described citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution are all carried out to microwave-assisted extraction processing 60min, wherein, the power of microwave-assisted extraction processing is 700W, collects citronella essential oil, betel leaf essential oil and camphor Seed essential oil, and calculate the oil rate;

(4) according to the above-mentioned parts by weight ratio, after the citronella quintessence oil, the betel leaf quintessence oil and the camphor seed quintessence oil are mixed with Tween 80 and water, the described pesticide made from the pure natural plant quintessence oil is obtained.

Example 3

The present embodiment provides a pesticide made from pure natural plant essential oils and a preparation method thereof, specifically:

Formulation: In parts by weight, it includes the following components:

10 parts of citronella essential oil, 4 parts of betel leaf essential oil, 3 parts of camphor seed essential oil, 1 part of Tween 80 and 85 parts of water;

(1) take by weighing dry citronella, betel leaf and camphor seeds, and pulverize to obtain citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder respectively;

(2) take by weighing citronella coarse powder, betel leaf coarse powder and camphor seed coarse powder, and after mixing with water respectively, obtain citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution, wherein, citronella is thick The weight ratio of powder, betel leaf meal and camphor seed meal to water is 1:30;

(3) after described citronella mixed solution, betel leaf mixed solution and camphor seed mixed solution are all carried out to microwave-assisted extraction for 30min, wherein, the power of microwave-assisted extraction is 160W, collects citronella essential oil, betel leaf essential oil and camphor Seed essential oil, and calculate the oil rate;

(4) according to the above-mentioned parts by weight ratio, after the citronella quintessence oil, the betel leaf quintessence oil and the camphor seed quintessence oil are mixed with Tween 80 and water, the described pesticide made from the pure natural plant quintessence oil is obtained.

Pathogenic bacteria growth inhibition test and optimal use concentration screening test

The present invention also carried out a pathogenic bacteria growth inhibition experiment and an optimal use concentration screening experiment for the pesticide prepared in the above-mentioned embodiment. The specific methods and results are as follows:

(1) Pathogenic bacteria growth inhibition test 1:

In this antibacterial experiment, Pseudomonas guava was used as the pathogen, and three kinds of single essential oils, namely citronella essential oil, betel leaf essential oil and camphor seed essential oil, and the pesticides made of pure natural plant essential oils obtained in Example 1 were used to inhibit the bacteria. The specific experimental method and experimental results are as follows:

1.1 Experimental conditions:

The diameter of the pathogen-Pseudomonas guava cake was 6mm, the concentration of three kinds of plant essential oils and pesticides was 25μl/ml, and the operation method The bacteria cake was placed on the PDA solid medium, the culture temperature was 25°C, and the culture time was 96h.

1.2 Experimental results:

The results of the growth inhibition experiment of pathogenic bacteria are shown in Figure 1. It can be seen from the figure that when the incubation time is 0-24h, the growth inhibition effects of the three single essential oils and the pesticides made of pure natural plant essential oils on pathogenic bacteria are basically the same , the colony diameter is 6.0mm, but with the continuous extension of the cultivation time, the above-mentioned four kinds of substances have a great difference in the growth inhibition effect of pathogenic bacteria, and the pesticide made of pure natural plant essential oil in the embodiment of the present invention 1 is effective against pathogenic bacteria. When the culture time reached 96h, citronella essential oil, betel leaf essential oil and camphor seed essential oil had no significant growth inhibition effect on pathogenic bacteria, and the colony diameters were about 8.25mm, 6.75mm, and 7.4mm, respectively. The colony diameter of Example 1 is still 6.0mm, thus it can be seen that, compared with a single essential oil, the pesticide in Example 1 of the present invention has always maintained a better bacteriostatic effect on pathogenic bacteria from the start of cultivation to 96h from cultivation;

The effects of the three essential oils and plant pesticides on the colony growth of pathogenic bacteria are shown in Figure 2, wherein Figure 2-A is a blank control diagram, no drugs and essential oils are added to the medium, and the pathogenic bacteria grow normally after 96h of inoculation with pathogenic bacteria and culture; Figures 2-B, 2-C, and 2-D are the culture medium containing 25 μl/ml camphor essential oil, the culture medium containing 25 μl/ml betel leaf essential oil, and the culture medium containing 25 μl/ml citronella leaf essential oil, inoculated with pathogenic bacteria After culturing for 96h, it can be seen that the above-mentioned three kinds of single plant essential oils all show different degrees of growth inhibition to pathogenic bacteria, but the growth inhibition is not very significant; Fig. 2-E is a pure natural plant containing the described examples of the application The medium of pesticide (25μl/ml) made of essential oil, after inoculation with pathogenic bacteria and cultured for 96h, showed obvious growth inhibition effect on pathogenic bacteria.

(2) Optimal use concentration screening experiment:

On the basis of the above experiments, the embodiment of the present invention further screened the optimal use concentration of pesticides, as follows:

2.1 Experimental method:

Experimental conditions: the diameter of Pseudomonas guava cake is 6mm, the concentration of pesticides used is 25μl/ml, 50μl/ml, 75μl/ml, 100μl/ml, and the operation method is to place the bacteria cake on the PDA solid medium and cultivate it. The temperature was 25°C and the incubation time was 96h;

2.2 Experimental results:

The results of the optimal use concentration screening experiment are shown in Figure 3. It can be seen from the figure that when the incubation time is 0-24h, the growth inhibition effect of different concentrations of pesticides on pathogenic bacteria is basically the same, and the colony diameter is 6.0mm. However, with the continuous extension of the incubation time, the above four concentrations of pesticides have great differences in the growth inhibition of pathogenic bacteria, and when the concentration of the drug is 100 μl/ml, the growth inhibition effect of the pathogenic bacteria is the best, when the incubation time reaches 96h , the other three concentrations of drugs have no significant inhibitory effect on the growth of pathogenic bacteria, and the colony diameters are about 7.75mm, 7.0mm, and 6.5mm, respectively, while the colony diameter when the drug concentration is 100 μl/ml is still 6.0mm, which shows that , Compared with other drug concentrations, the drug concentration of 100μl/ml has the best inhibitory effect on the growth of pathogenic bacteria from the beginning of culture to 96h. Therefore, the optimal concentration of the drug is 100μl/ml.

(3) Pathogenic bacteria growth inhibition experiment 2:

In this antibacterial experiment, three phytopathogenic bacteria, Erwinia carotovora subsp carotovora borgey, Ralstonia solanacearum, and S. acidiscabies, were used as pathogens, and citronella essential oil, betel leaf essential oil and camphor seeds were used respectively. The pesticide that three kinds of single essential oils of essential oil, embodiment 1 are made by pure natural plant essential oil carry out antibacterial experiment, and its concrete experimental method and experimental result are:

3.1 Experimental method:

Take the strains stored on the slant, activate the bacteria at 37°C for 24 hours, and then use an inoculation loop to pick a small amount of colonies from the activated slant medium and inoculate them into the corresponding liquid medium, and put them into a constant temperature shaking incubator for logarithmic growth. During the period, use the plate counting method to adjust the bacterial concentration to 10 ⁵ -10 ⁶ cfu/ml, for use;

Select qualitative filter paper with uniform texture and strong water absorption, use a puncher to punch out circular paper pieces with a diameter of 8 mm (sterilized by autoclaving) from the filter paper, and package them in a dry and clean petri dish. , placed in the ultra-clean bench for backup;

Under sterile conditions, pour 20-25 ml of sterilized medium into a petri dish while it is still hot, and after the medium is cooled and solidified, remove three phytopathogenic bacteria (Erwinia carotovora subsp carotovora borgey, Ralstonia solanacearum Ralstonia solanacearum, S. acidiscabies scab) 100 μl of bacterial suspension with a concentration of 10 ⁵ -10 ⁶ cfu/ml was evenly spread into the corresponding plate medium, and after the medium solidified, clamp it with sterile tweezers Take the 8mm sterile circular filter paper that has been sterilized, soaked in plant essential oil and drained and stick it on the solid plate, then move the petri dish into a constant temperature incubator, bacteria (37°C, 24h), and observe whether the plate is The inhibition zone appeared, and the diameter of the inhibition zone was measured respectively.

3.2 Experimental results:

The test result of this antibacterial experiment is shown in Figure 4, as can be seen from the figure, the growth inhibitory effect of three kinds of single essential oils on Erwinia, Ralstonia solanacearum and scab pathogen is not obvious, and the embodiment of the present invention is used. The prepared pesticide has obvious inhibition zone on the above three kinds of pathogenic bacteria, it can be seen that the pesticide provided by the present invention has excellent growth inhibition effect on all three kinds of plant pathogenic bacteria.

It can be seen from the above that, compared with a single essential oil, the pure natural plant essential oil pesticide prepared by the present application has a significant growth inhibitory effect on pathogenic bacteria, and this pesticide has natural components, low cost, multiple active components and good control effect. It can be seen that the pesticide made from pure natural plant essential oil proposed in this application can be applied to the application of botanical pesticides.

Claims (9)

1. The application of the pesticide prepared from the pure natural plant essential oil in preventing and treating plant diseases is characterized in that the pesticide prepared from the pure natural plant essential oil comprises the following components in parts by weight:

5-15 parts of citronella essential oil, 3-5 parts of areca leaf essential oil, 2-5 parts of cinnamomum camphora seed essential oil, 1-2 parts of surfactant and 80-90 parts of water;

the pesticide prepared from the pure natural plant essential oil is prepared by the following method:

weighing dried citronella, areca leaf and cinnamomum camphora seed, and crushing to obtain coarse citronella powder, coarse areca leaf powder and coarse cinnamomum camphora seed powder;

respectively taking citronella coarse powder, betel nut leaf coarse powder and cinnamomum camphora seed coarse powder as raw materials, performing essential oil extraction treatment to obtain citronella essential oil, betel nut leaf essential oil and cinnamomum camphora seed essential oil, and calculating the oil yield, wherein the method for extracting and treating the essential oil is a microwave-assisted extraction method;

according to the weight part ratio, the citronella essential oil, the betel nut leaf essential oil and the cinnamomum camphora seed essential oil are uniformly mixed with the surfactant and water to prepare the pesticide prepared from the pure natural plant essential oil.

2. The application of the pesticide prepared from the pure natural plant essential oil in controlling plant diseases according to claim 1 is characterized by comprising the following components in parts by weight:

5 parts of citronella essential oil, 3 parts of betel nut leaf essential oil, 2 parts of camphor seed essential oil, 1 part of surfactant and 90 parts of water.

3. The use of a pesticide made from pure natural plant essential oil in the control of plant diseases as claimed in claim 2, wherein the surfactant is any one or more of tween 80, poloxamer or span 80.

4. The use of a pesticide prepared from pure natural plant essential oil for controlling plant diseases according to claim 1, wherein the formulation of the pesticide prepared from pure natural plant essential oil is any one of spray, wettable powder or dispersible oil.

5. The application of the pesticide prepared from the pure natural plant essential oil in preventing and treating plant diseases according to claim 1, wherein the method for extracting the citronella essential oil, the betel palm leaf essential oil and the cinnamomum camphora seed essential oil by the microwave-assisted extraction method comprises the following steps:

weighing the citronella coarse powder, the betel nut leaf coarse powder and the cinnamomum camphora seed coarse powder, and respectively and uniformly mixing the citronella coarse powder, the betel nut leaf coarse powder and the cinnamomum camphora seed coarse powder with water to obtain a citronella mixed solution, an betel nut leaf mixed solution and a cinnamomum camphora seed mixed solution;

and (3) performing microwave-assisted extraction treatment on the citronella mixed solution, the betel nut leaf mixed solution and the cinnamomum camphora seed mixed solution for 15-60min, collecting citronella essential oil, betel nut leaf essential oil and cinnamomum camphora seed essential oil, and calculating the oil yield.

6. The use of a pesticide made of pure natural plant essential oil for controlling plant diseases according to claim 5, wherein the weight ratio of the citronella coarse powder, the betel nut leaf coarse powder and the cinnamomum camphora seed coarse powder to water is 1: (20-50), the power of the microwave-assisted extraction treatment is 160-700W.

7. The use of a pesticide made of pure natural plant essential oil for controlling plant diseases according to claim 6, wherein the weight ratio of the citronella coarse powder, the betel nut leaf coarse powder and the cinnamomum camphora seed coarse powder to water is 1: the power of the microwave-assisted extraction process was 550W 20.

8. The use of the pure natural plant essential oil-containing pesticide for controlling plant diseases according to claim 1, wherein the pure natural plant essential oil-containing pesticide is used for controlling plant diseases caused by Neurospora, Penicillium, Aspergillus, Cladosporium, Fusarium, and Geranium.

9. The use of the pure natural plant essential oil-made pesticide for controlling plant diseases according to claim 8, characterized in that the pure natural plant essential oil-made pesticide is used for controlling pseudocercospora brown spot, rhizoctonia rot, gray mold, black spot, root rot, blight, rot, leaf spot, black root, fruit rot, rot and moldy core; the pesticide prepared from pure natural plant essential oil is applied to guava, banana, tomato, safflower creeping oxalis, cowpea, ligustrum japonicum, hyacinth bean, lotus root and thunder god vine.

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