Compound disease and pest control agent based on plant extract as core and preparation method of compound disease and pest control agent

Abstract

The invention relates to the field of agricultural pest control, and discloses a composite pest control agent based on a plant extract as a core. Comprising 15%-25% of honeysuckle extract, 10%-20% of podophyllum hexandrum extract, 15%-25% of camellia peel extract, 10%-20% of wikstroemia indica extract, 10%-20% of senecio scandens extract, 10%-20% of lycoris radiate extract, 1%-3% of a synergist, 5%-10% of an emulsifier and a solvent. According to the invention, a plurality of plant extracts are fused, and effective prevention and control of a plurality of fungi, bacterial diseases and pests are realized through accurate optimization of the ratio. Compared with a current technology which only adopts a single plant extract, the method has the advantages that the comprehensive prevention and treatment efficiency is remarkably improved, the problems of limited prevention and treatment range and poor multi-pest control effect are successfully solved, and the blank in the research and application field of the compound plant extract prevention and treatment agent is filled.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural pest control, and in particular to a composite pest control agent based on plant extracts as a core and a preparation method thereof. Background Art

[0002] Agricultural pest control is a key link in modern agricultural production. For a long time, chemical pesticides have been widely used due to their high efficiency and rapid control effects. However, with the extensive use of chemical pesticides, their disadvantages have gradually emerged, including increased resistance of pests and diseases, increased environmental pollution, and hidden dangers in food safety. These problems not only limit the sustainable use of chemical pesticides, but also pose a threat to agricultural ecosystems and human health.

[0003] In recent years, plant extracts have received widespread attention as a natural, green and safe means of pest control. Plant extracts are rich in bioactive ingredients and can play a preventive and therapeutic role on a variety of pathogens and pests. However, the existing pest control technology based on plant extracts also has obvious shortcomings, including narrow prevention and control range, poor stability of active ingredients, insufficient compound research, and high cost of industrial production. Most of the existing technologies are based on a single plant extract, which has a single target and is difficult to provide effective prevention and control of complex pests and diseases. In addition, the stability of the active ingredients in plant extracts is easily affected by environmental factors (such as light, temperature, and humidity), resulting in a decrease in effect during storage and use. Moreover, there is little research on the mechanism of synergy between different plant extracts, and it is difficult to achieve a synergistic effect through compounding.

[0004] In terms of formulation technology, existing plant extract pest control agents are mainly in powder or simple solution form, which have poor stability and long-lasting effect and are difficult to adapt to changing field environmental conditions. In addition, traditional extraction processes such as hot reflux extraction and solvent extraction have problems such as low extraction efficiency, high energy consumption, easy degradation of active ingredients and environmental pollution, which further restrict the development and application of plant extracts.

[0005] Therefore, the present invention proposes a composite pest control agent based on plant extracts as the core and a preparation method to solve the deficiencies of the prior art. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a composite pest control agent based on plant extracts and a preparation method thereof, aiming to solve the problems of the existing plant extract pest control agents, such as narrow control range, poor stability, insufficient synergistic research, and limited industrial production. By scientifically compounding a variety of plant extracts, optimizing the extraction process and formulation technology, the present invention effectively improves the comprehensive control effect, stability, and environmental adaptability of the pest control agent.

[0007] To achieve the above objectives, the present invention is implemented by the following technical scheme: a composite pest control agent based on plant extracts as the core, comprising plant extracts and auxiliary materials in the following weight ranges:

[0008] Honeysuckle extract: 15%-25%;

[0009] Psoralea corylifolia extract: 10%-20%;

[0010] Camellia peel extract: 15%-25%;

[0011] Rhizoma Dioscoreae extract: 10%-20%;

[0012] Senecio extract: 10%-20%;

[0013] Lycoris radiata extract: 10%-20%;

[0014] Synergist: 1%-3%;

[0015] Emulsifier: 5%-10%;

[0016] Solvent: Balance.

[0017] Preferably, the main active ingredient of the honeysuckle extract is chlorogenic acid, and its content is not less than 10%; the main active ingredient of the peach notoginseng extract is lignan compounds, and its content is not less than 8%; the main active ingredient of the camellia peel extract is saponin, and its content is not less than 15%.

[0018] Preferably, the synergist is selected from natural surfactants, including but not limited to tea saponin, saponin compounds or their combinations; the emulsifier is selected from polyethylene glycol, Tween emulsifiers or Span emulsifiers.

[0019] Preferably, the solvent is selected from distilled water, deionized water or purified soft water.

[0020] Preferably, the control agent can be prepared into a suspension or microcapsule formulation, wherein:

[0021] In the suspension, the total content of plant extract is 30%-50%, the content of emulsifier is 5%-10%, and the rest is water;

[0022] In the microcapsule dosage form, the plant extracts are encapsulated by polylactic acid, and the core-wall material ratio is 1:5.

[0023] Preferably, the preparation method of the composite pest control agent based on plant extracts as the core comprises the following steps:

[0024] Raw material handling:

[0025] The herbal medicines were cleaned, dried and crushed into powder with a particle size of 0.5 mm;

[0026] extract:

[0027] Distilled water was used as the solvent with a liquid-to-solid ratio of 8:1;

[0028] The extraction method was a combination of ultrasound-assisted extraction and microwave-assisted extraction;

[0029] The extracts are filtered and combined;

[0030] Concentration and purification:

[0031] The extract was concentrated under reduced pressure to 1 / 5 of the original volume;

[0032] Use ultrafiltration membranes to remove large molecular impurities;

[0033] freeze-drying the concentrated solution to prepare a powdered plant extract;

[0034] Compounding:

[0035] Weigh the plant extract according to the weight range;

[0036] Add emulsifier and synergist, stir well;

[0037] Formulation:

[0038] The mixture is prepared into a suspension or a microcapsule dosage form by an emulsification-solvent evaporation method.

[0039] Preferably, the preparation steps of the microcapsule dosage form include:

[0040] The extract was dissolved in distilled water and polylactic acid was dissolved in dichloromethane;

[0041] The core and wall materials are emulsified and mixed in a ratio of 1:5;

[0042] The emulsion was formed by high-speed stirring and then the dichloromethane was volatilized to prepare microcapsule particles.

[0043] Preferably, the parameters of the ultrasonic-assisted extraction are a frequency of 40 kHz, a power of 500 W, a temperature controlled between 50° C. and 70° C., and an extraction time of 20 to 40 minutes; the parameters of the microwave-assisted extraction are a power of 200 W to 400 W, and an extraction time of 8 to 12 minutes.

[0044] Preferably, the ultrafiltration membrane has a molecular weight cutoff of 10 kDa to 30 kDa, and is used to separate macromolecular impurities and insoluble particles in the extract while retaining low molecular weight active ingredients in the plant extract.

[0045] Preferably, the active ingredients of the extract are detected by high performance liquid chromatography, wherein:

[0046] The chlorogenic acid content of honeysuckle extract is not less than 10%;

[0047] The content of lignan compounds in the extract of Psoralea corylifolia is not less than 8%;

[0048] The tea saponin content of the camellia peel extract is not less than 15%.

[0049] The invention provides a composite pest control agent based on plant extracts as a core and a preparation method thereof.

[0050] It has the following beneficial effects:

[0051] 1. The present invention scientifically compounds a variety of plant extracts such as honeysuckle, peach, camellia peel, lycoris radiata, Senecio chinensis and Lycoris radiata, and optimizes the weight range of the active ingredients based on the synergistic effect, thereby achieving broad-spectrum control of fungal diseases (such as powdery mildew and downy mildew), bacterial diseases (such as leaf spot), piercing-sucking mouthparts pests (such as aphids) and underground pests (such as root-knot nematodes). Compared with the problem that the control agent with a single plant extract as the core in the prior art can only carry out targeted control of specific diseases or pests, the present invention significantly improves the efficiency of integrated pest control by optimizing the compounding ratio of multiple extracts, solves the shortcomings of the prior art that the control range is narrow and the simultaneous control effect of multiple pests is poor, and fills the gap in the research and application of composite plant extract control agents.

[0052] 2. The present invention innovatively adopts an extraction technology that combines ultrasonic-assisted extraction with microwave-assisted extraction, and significantly improves the extraction efficiency and quality of active ingredients in plant extracts by optimizing extraction conditions (such as ultrasonic frequency of 40kHz, power of 500W, microwave power of 200-400W, and extraction time of 8-40 minutes). Compared with the problems of low extraction efficiency, high energy consumption, and easy degradation of some active ingredients in the single traditional hot reflux extraction process in the prior art, the present invention effectively solves the extraction problems in the prior art, achieves the purpose of improving the extraction rate, shortening the extraction time, and protecting the active ingredients, and provides technical support for the efficient preparation of high-purity plant extracts. At the same time, the present invention uses water as the extraction solvent, abandons the use of traditional organic solvents, and meets the requirements of green environmental protection.

[0053] 3. The present invention combines polylactic acid encapsulation technology with emulsification technology, and by preparing microcapsule dosage forms and suspension dosage forms, the active ingredients of plant extracts can achieve a sustained release effect after application, significantly enhancing the environmental stability and persistence of pest control agents. The core-wall material ratio of the microcapsule dosage form is optimized to 1:5, the plant extract content in the suspension is controlled at 30%-50%, and the emulsifier content is controlled at 5%-10%, ensuring the stability and ease of use of the finished product. Compared with the problem of poor stability of active ingredients in plant extracts and susceptibility to environmental factors (such as high temperature and ultraviolet rays) in the prior art, the present invention solves the problem of attenuation of the effect of the control agent due to insufficient stability, and significantly improves the actual field application effect of the product. At the same time, the sustained-release characteristics of the product prolong the action time, reduce the application frequency of the control agent, and reduce agricultural production costs.

[0054] 4. The pest control agent of the present invention uses natural plant extracts as the main ingredients, and by selecting natural synergists such as tea saponin and water as solvents, it achieves a green, environmentally friendly, and residue-free technical effect. The use of a non-toxic and harmless extraction process avoids the pollution of chemical pesticides to the environment and food. Compared with the problems of ecological damage, food safety hazards, and environmental pollution caused by the control agents based on chemical synthetic pesticides in the prior art, the present invention abandons toxic chemical components at the source, solves the negative impact of the prior art on the ecological environment and crop quality, conforms to the development direction of sustainable agriculture, and provides a reliable guarantee for safe production. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The present invention is a flow chart of the preparation method of a composite pest control agent based on plant extracts as the core. DETAILED DESCRIPTION

[0056] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Please see attached picture:

[0058] Embodiment 1:

[0059] formula:

[0060] According to the technical solution of the present invention, the following plant extracts and auxiliary materials are selected and compounded by weight percentage:

[0061] Honeysuckle extract: 20%;

[0062] Psoralea corylifolia extract: 15%;

[0063] Camellia sinensis peel extract: 20%;

[0064] Rhizoma Dioscoreae extract: 15%;

[0065] Senecio grandiflora extract: 15%;

[0066] Lycoris radiata extract: 15%;

[0067] Synergist (tea saponin): 2%;

[0068] Emulsifier (PEG-400): 8%;

[0069] Solvent (distilled water): balance.

[0070] Preparation process:

[0071] Raw material processing: wash honeysuckle, peach, camellia peel, king of angelica, Senecio and Lycoris radiata separately, dry (50℃), and grind into powder with a particle size of 0.5mm.

[0072] Extraction process:

[0073] Ultrasonic-assisted extraction: plant powder was mixed with distilled water at a liquid-to-solid ratio of 8:1, and extracted at 40kHz, 500W, and 60°C for 30 minutes;

[0074] Microwave-assisted extraction: The extract was treated with 300 W microwave for 10 min;

[0075] The extracts were filtered through gauze and combined.

[0076] Concentration and purification:

[0077] The extract was concentrated to 1 / 5 of the original volume by rotary evaporation under reduced pressure;

[0078] Ultrafiltration (MWCO10kDa) to remove large molecular impurities;

[0079] Freeze-drying gave the extract in powder form.

[0080] Compounding and formulation:

[0081] Weigh the extract powder according to the formula ratio, and add the emulsifier and synergist;

[0082] Use a high-speed shear disperser to stir evenly and prepare a suspension dosage form.

[0083] Effect test

[0084] Disease control rate: The control rates for powdery mildew and downy mildew are 92.3% and 90.5% respectively;

[0085] Pest mortality: The mortality rates for aphids and root-knot nematodes were 95.2% and 93.6% respectively;

[0086] Lasting period: Field trials show the lasting period is 15 days.

[0087] Summary of embodiments:

[0088] The composition ratio and process parameters of Example 1 are strictly controlled within the recommended range of the technical solution, showing the best pest control effect and persistence, verifying the effectiveness of synergistic compounding and extraction process optimization. The synergistic effect of the ingredients significantly enhances the broad-spectrum control ability, while the moderate extraction parameters balance the extraction efficiency and energy consumption, providing an optimization path for industrial production.

[0089] Example 2: Example with ingredients and process parameters below the range values

[0090] formula:

[0091] Honeysuckle extract: 10%;

[0092] Psoralea corylifolia extract: 8%;

[0093] Camellia sinensis peel extract: 10%;

[0094] Rhizoma Dioscoreae extract: 8%;

[0095] Senecio grandiflora extract: 8%;

[0096] Lycoris radiata extract: 8%;

[0097] Synergist (tea saponin): 0.5%;

[0098] Emulsifier (PEG-400): 4%;

[0099] Solvent (distilled water): balance.

[0100] Preparation process:

[0101] Raw material treatment: same as Example 1.

[0102] Extraction process:

[0103] Ultrasonic-assisted extraction: 35kHz, 400W, 50℃ for 20 minutes;

[0104] Microwave-assisted extraction: 200 W microwave treatment for 8 min;

[0105] The extracts were filtered through gauze and combined.

[0106] Concentration and purification:

[0107] The extract was concentrated under reduced pressure to 1 / 3 of the original volume;

[0108] Use ultrafiltration membrane (MWCO5kDa) for impurity removal;

[0109] The extract was freeze-dried to prepare a powdered form.

[0110] Compounding and formulation:

[0111] The extracts are compounded according to the formula ratio to prepare a suspension dosage form.

[0112] Effect test:

[0113] Disease control rate: The control rates for powdery mildew and downy mildew were 75.4% and 73.1% respectively;

[0114] Pest mortality: The mortality rates for aphids and root-knot nematodes were 76.8% and 74.5% respectively;

[0115] Duration of effect: 10 days.

[0116] Summary of embodiments:

[0117] The component ratio and extraction process parameters of Example 2 are lower than the recommended range of the technical solution, resulting in a significant decrease in the control effect. The main reason is that the content of active ingredients is insufficient, the synergistic effect cannot be fully exerted, and the intensity of the extraction parameters is insufficient, the extraction efficiency is low, and the content of active ingredients in the plant extract is affected. In addition, the content of synergist and emulsifier is insufficient, which further reduces the permeability and stability of the suspension. The results show that the components and parameters below the range values ​​are difficult to meet the actual field control needs.

[0118] Embodiment 3:

[0119] formula

[0120] Honeysuckle extract: 30%;

[0121] Psoralea corylifolia extract: 25%;

[0122] Camellia sinensis peel extract: 30%;

[0123] Rhizoma Dioscoreae extract: 20%;

[0124] Senecio grandiflora extract: 20%;

[0125] Lycoris radiata extract: 20%;

[0126] Enhancer (tea saponin): 5%;

[0127] Emulsifier (PEG-400): 12%;

[0128] Solvent (distilled water): balance.

[0129] Preparation process:

[0130] Raw material treatment: same as Example 1.

[0131] Extraction process:

[0132] Ultrasonic-assisted extraction: 45kHz, 600W, 70℃ for 40 minutes;

[0133] Microwave-assisted extraction: 400 W microwave treatment for 15 min;

[0134] The extracts were filtered through gauze and combined.

[0135] Concentration and purification:

[0136] The extract was concentrated under reduced pressure to 1 / 10 of its original volume;

[0137] Ultrafiltration membrane (MWCO 30 kDa) was used for impurity removal;

[0138] The extract was freeze-dried to prepare a powdered form.

[0139] Compounding and formulation:

[0140] The extracts are compounded according to the formula ratio to prepare a microcapsule dosage form.

[0141] Effect test:

[0142] Disease control rate: The control rates for powdery mildew and downy mildew are 94.8% and 92.7% respectively;

[0143] Pest mortality: The mortality rates for aphids and root-knot nematodes were 96.1% and 94.8% respectively;

[0144] Lasting period: 15-18 days.

[0145] Summary of embodiments:

[0146] The ingredient ratio and extraction process parameters of Example 3 are higher than the recommended range. Although the control effect is slightly improved, it also brings some negative effects. Excessive extraction intensity increases energy consumption, and some active ingredients may be degraded due to high temperature and long-term extraction. Excessive ingredient ratios and the use of emulsifiers increase production costs and affect the economic feasibility of industrial promotion. The results show that although excessive parameters can improve the effect to a certain extent, they are not feasible for large-scale application.

[0147] Comprehensive analysis:

[0148] Example 1 fully demonstrates the rationality and superiority of the technical solution, and achieves an optimal balance between pest control effect, stability and industrial feasibility.

[0149] Example 2 shows that insufficient ingredients and parameters will lead to a decrease in the content of active ingredients, weakened synergistic effects, and ultimately affect the control effect.

[0150] Although the effect of Example 3 is slightly better than that of Example 1, the cost is increased and the stability faces challenges, so it is not suitable for large-scale promotion.

[0151] Comparative experiment:

[0152] Comparative experiment 1: Broad spectrum test

[0153] Purpose

[0154] The broad-spectrum control capability of the composite pest control agent of the present invention on various pests and diseases was verified, and compared with single plant extracts and chemical pesticides.

[0155] Experimental process:

[0156] Subjects:

[0157] Fungal diseases: powdery mildew of cucumber (inoculation of cucumber plants).

[0158] Bacterial diseases: Tomato leaf spot (inoculation of tomato plants).

[0159] Pests: Pepper aphids (release aphid colonies to infect plants).

[0160] Treatment Group:

[0161] The composite control agent group of the present invention adopts the formula in Example 1.

[0162] Single plant extract group: A 20% aqueous solution of honeysuckle extract was used without other ingredients.

[0163] Chemical pesticide group: Thiophanate-methyl (for fungal control) and acetamiprid (for insect control) were used, diluted at conventional dosages.

[0164] Control group: spray with clean water.

[0165] Experimental steps:

[0166] Infection treatment: Release pathogens or aphids on cucumber leaves, tomato leaves and pepper plants respectively to ensure uniform infection.

[0167] Spray the control agent: spray once every 7 days for two consecutive times, and observe the disease control effect and changes in the number of pests.

[0168] Data collection: The disease index and pest survival rate were calculated on the 7th and 14th days after application.

[0169] Data Analysis:

[0170] Disease control rate (%) = [(disease index of control group - disease index of treatment group) / disease index of control group] × 100%;

[0171] Pest mortality (%) = [(number of pests in the control group - number of pests in the treatment group) / number of pests in the control group] × 100%.

[0172] Experimental results:

[0173] Control Agents Powdery mildew control rate (%) Leaf spot control rate (%) Aphid mortality (%) The present invention 92.3 90.1 95.2 Single plant extract 60.5 55.4 30.2 Chemical pesticides 93.5 88.9 97.1 Control group 10.2 8.6 8.3

[0174] Analysis and summary:

[0175] Existing technical solutions are inadequate: single plant extracts are only effective against specific diseases, cannot take into account pest control, and have poor broad-spectrum control.

[0176] The improvement of the present invention is that through the synergistic effect of the composite formula, a highly effective control effect is shown on fungi, bacteria and pests, which is equivalent to that of chemical pesticides, but avoids the environmental pollution.

[0177] Beneficial effects: It solves the shortcoming of narrow pest control range in the prior art and is suitable for the control of complex field compound pests and diseases.

[0178] Comparative experiment 2: control effect test

[0179] Purpose:

[0180] The control effect of the control agent of the present invention on powdery mildew and aphids was verified and compared with single plant extracts and chemical pesticides.

[0181] Experimental process:

[0182] Subjects:

[0183] Powdery mildew (infection of cucumber plants).

[0184] Aphids (pepper plant infestation).

[0185] Treatment Group:

[0186] The composite control agent group of the present invention: the formula of Example 1.

[0187] Single plant extract group: using 15% aqueous solution of Psoralea corylifolia extract without other components.

[0188] Chemical pesticide group: Thiophanate methyl (disease prevention) and acetamiprid (insect prevention) were used respectively.

[0189] Control group: spray with clean water.

[0190] Experimental steps:

[0191] Powdery mildew: Spray the pathogen suspension (concentration 10 6 CFU / mL);

[0192] Aphids: Aphids (100 / plant) were released on pepper plants.

[0193] Spraying of control agents: Spray the control agents 24 hours after the first inoculation, and spray once every 7 days for 14 days.

[0194] Data collection: record the changes in diseased area and aphid number, and calculate the disease control rate and pest mortality rate.

[0195] Experimental results:

[0196] Group Powdery mildew control rate (%) Aphid mortality (%) The present invention 92.3 95.2 Single plant extract 55.7 31.8 Chemical pesticides 93.5 97.1 Control group 10.4 8.5

[0197] Analysis and summary:

[0198] Existing technical solutions are inadequate: single extracts have very poor control effects on aphids and limited disease control capabilities.

[0199] The improvement of the present invention is that the synergistic effect of the composite extracts significantly improves the control effect and can control diseases and pests at the same time.

[0200] Beneficial effects: It solves the problem of insufficient integrated pest control capabilities of single plant extracts.

[0201] Comparative experiment 3: stability test

[0202] Purpose

[0203] The stability of the microcapsule dosage form of the present invention under high temperature and strong light conditions was verified and compared with the prior art.

[0204] Experimental Procedure

[0205] Treatment Group:

[0206] The present invention (microcapsule dosage form): prepared according to Example 1.

[0207] Single plant extract suspension: Camellia sinensis peel extract suspension (20%) was prepared directly.

[0208] Chemical pesticide solution: Use acetamiprid (500 times diluted).

[0209] Experimental methods:

[0210] High temperature treatment: Place in a 40℃ constant temperature box for 30 days, and take samples every 7 days to test activity.

[0211] Strong light treatment: Place the reagent in a strong light environment (3000 Lux) for 30 days, and take samples every 7 days to test activity.

[0212] Activity detection: High performance liquid chromatography (HPLC) was used to detect the changes in the content of active ingredients and calculate the activity preservation rate.

[0213] Experimental results:

[0214]

[0215] Analysis and summary

[0216] The existing technical solutions are inadequate: single plant extracts are easily inactivated under high temperature and strong light, and the preservation rate of active ingredients is low.

[0217] The improvement of the present invention is that the active ingredients are encapsulated by microcapsule technology, which greatly improves the environmental adaptability and storage stability.

[0218] Beneficial effects: It solves the problem of poor stability of plant extracts and provides better feasibility for field application.

[0219] Comparative experiment 4: Environmental protection test

[0220] Purpose

[0221] The impact of the present invention on soil microbial ecology was tested, and its environmental friendliness was compared with the prior art.

[0222] Experimental Procedure

[0223] Treatment Group:

[0224] The composite control agent group of the present invention: the formula of Example 1.

[0225] Single plant extract group: honeysuckle extract (20%).

[0226] Chemical pesticide group: Thiophanate-methyl diluted 600 times.

[0227] Control group: no treatment.

[0228] Experimental methods:

[0229] The reagent was sprayed in the field, and soil samples (0-15 cm layer) were collected to determine the number and diversity of microorganisms at 0, 10, and 30 days.

[0230] Microbial count: Counted by plate dilution method.

[0231] Microbial diversity: analyzed by PCR-DGGE.

[0232] Experimental results:

[0233]

[0234]

[0235] Analysis and summary:

[0236] Existing technical solutions are insufficient: chemical pesticides significantly reduce the number of soil microorganisms and destroy the ecological balance of the soil.

[0237] The improvement of the present invention is that the natural plant extract has no obvious negative impact on the soil and is ecologically safe.

[0238] Beneficial effects: It overcomes the major drawback of chemical pesticides in terms of environmental pollution.

[0239] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite pest control agent based on plant extracts, characterized in that: Includes plant extracts and excipients in the following weight ranges: Honeysuckle extract: 15%-25%; Psoralea corylifolia extract: 10%-20%; Camellia peel extract: 15%-25%; Rhizoma Dioscoreae extract: 10%-20%; Senecio extract: 10%-20%; Lycoris radiata extract: 10%-20%; Synergist: 1%-3%; Emulsifier: 5%-10%; Solvent: Balance.

2. The composite pest control agent based on plant extracts as the core according to claim 1, characterized in that: The main active ingredient of the honeysuckle extract is chlorogenic acid, whose content is not less than 10%; the main active ingredient of the peach extract is lignan compounds, whose content is not less than 8%; the main active ingredient of the camellia peel extract is tea saponin, whose content is not less than 15%.

3. The composite pest control agent based on plant extracts as the core and the preparation method according to claim 1, characterized in that: The synergist is selected from natural surfactants, including but not limited to tea saponin, saponin compounds or their combinations; the emulsifier is selected from polyethylene glycol, Tween emulsifiers or Span emulsifiers.

4. The composite pest control agent based on plant extracts as the core and the preparation method according to claim 1, characterized in that: The solvent is selected from distilled water, deionized water or purified soft water.

5. The composite pest control agent based on plant extracts as the core according to claim 1, characterized in that: The control agent can be prepared into a suspension or microcapsule formulation, wherein: In the suspension, the total content of plant extract is 30%-50%, the content of emulsifier is 5%-10%, and the rest is water; In the microcapsule dosage form, the plant extracts are encapsulated by polylactic acid, and the core-wall material ratio is 1:

5.

6. The method for preparing a composite pest control agent based on plant extracts as a core according to any one of claims 1 to 5, characterized in that: The following steps are involved: Raw material handling: The herbal medicines were cleaned, dried and crushed into powder with a particle size of 0.5 mm; extract: Distilled water was used as the solvent with a liquid-to-solid ratio of 8:1; The extraction method was a combination of ultrasound-assisted extraction and microwave-assisted extraction; The extracts are filtered and combined; Concentration and purification: The extract was concentrated under reduced pressure to 1 / 5 of the original volume; Use ultrafiltration membranes to remove large molecular impurities; freeze-drying the concentrated solution to prepare a powdered plant extract; Compounding: Weigh the plant extract according to the weight range; Add emulsifier and synergist, stir well; Formulation: The mixture is prepared into a suspension or a microcapsule dosage form by an emulsification-solvent evaporation method.

7. The method for preparing a composite pest control agent based on plant extracts as a core according to claim 6, characterized in that: The preparation steps of the microcapsule dosage form include: The extract was dissolved in distilled water and polylactic acid was dissolved in dichloromethane; The core and wall materials are emulsified and mixed in a ratio of 1:5; The emulsion was formed by high-speed stirring and then the dichloromethane was volatilized to prepare microcapsule particles.

8. The method for preparing a composite pest control agent based on plant extracts as a core according to claim 6, characterized in that: The parameters of the ultrasonic-assisted extraction are a frequency of 40kHz, a power of 500W, a temperature controlled between 50°C and 70°C, and an extraction time of 20 minutes to 40 minutes; the parameters of the microwave-assisted extraction are a power of 200W to 400W, and an extraction time of 8 minutes to 12 minutes.

9. The method for preparing a composite pest control agent based on plant extracts as a core according to claim 6, characterized in that: The ultrafiltration membrane has a molecular weight cutoff of 10 kDa to 30 kDa and is used to separate macromolecular impurities and insoluble particles in the extract while retaining low molecular weight active ingredients in the plant extract.

10. The method for preparing a composite pest control agent based on plant extracts as a core according to claim 6, characterized in that: The active ingredients of the extract were detected by high performance liquid chromatography, wherein: The chlorogenic acid content of honeysuckle extract is not less than 10%; The content of lignan compounds in the extract of Psoralea corylifolia is not less than 8%; The tea saponin content of the camellia peel extract is not less than 15%.

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