A mosquito repellent composition containing a plant-derived synergist and its application

Abstract

This invention discloses a mosquito repellent composition containing a plant-derived synergist and its application. The mosquito repellent composition includes the plant-derived synergist and a fluorinated pyrethroid, wherein the plant-derived synergist is β-caryophyllene, a mixture of β-caryophyllene and α-terpineol, or a mixture of β-caryophyllene and citronellol. The mosquito repellent composition proposed in this invention has the dual effects of inhibiting the activity of detoxification metabolic enzymes in insects and attracting mosquitoes, thus enhancing the repellent effect of pyrethroid active ingredients on mosquitoes while addressing insect metabolic resistance.

Description

Technical Field

[0001] This invention relates to the field of vector control technology, and in particular to a mosquito repellent composition containing a plant-derived synergist and its application. Background Technology

[0002] Fluorinated pyrethroids are the most commonly used active ingredient in modern mosquito repellent products (such as mosquito coils and liquid electric mosquito repellents). They work by interfering with the nervous system of mosquitoes to "knock them down" and "kill" them.

[0003] As a representative fluorinated pyrethroid, tetrafluoroethylene has extremely high biological activity. Compared to traditional conventional pyrethroids such as allethrin and acephate, only 1 / 10 of the dosage is needed in mosquito coil products to achieve the same mosquito-repellent effect; if the dosage is the same, the insecticidal effect can be up to 4 times that of traditional pyrethroids. As the core active ingredient in household mosquito repellent products, tetrafluoroethylene has developed significant resistance in mosquitoes with long-term use, leading to a significant decrease in the effectiveness of single-dose repellents. The current mainstream approach to addressing mosquito resistance is to add the chemical synergist ether (PBO) to the product. Its mechanism of action is to inhibit the activity of detoxification and metabolic enzymes in insects, thereby enhancing the control effect of tetrafluoroethylene. However, PBO has two major drawbacks: First, its safety is highly controversial, and its potential health risks have always been criticized, limiting its application in scenarios such as mothers and infants and sensitive groups; second, its synergistic activity decreases with long-term use, and mosquitoes become more adaptable to the "tetrafluoroethylene + PBO" combination after continuous application, gradually reducing the synergistic effect and failing to fundamentally delay the development of drug resistance.

[0004] Plant essential oils, as secondary metabolites of plants, possess multiple activities such as repelling insects, killing insects, and inhibiting insect growth. Furthermore, numerous studies have confirmed that some essential oils can simultaneously exert repellent effects and inhibit the activity of insect detoxification and metabolic enzymes. Theoretically, they can serve as alternatives to chemical synergists (such as PBO) and can be combined with tetrafluoroethylene to reduce the amount of chemical pesticides used and delay the development of pesticide resistance.

[0005] However, existing plant essential oil enhancement technologies have a core bottleneck: the chemical composition of essential oils extracted from plants in different regions and at different growth stages varies significantly, resulting in unstable enhancement effects of different batches of essential oils (e.g., repellency rates fluctuate between 15% and 60%), which seriously affects the commercialization process of plant-derived enhancers.

[0006] In summary, existing technologies face three major problems: first, mosquitoes are increasingly resistant to fluorinated pyrethroid insecticides; second, chemical synergists (PBOs) have poor safety and their synergistic activity is easily diminished; and third, plant essential oil synergists have poor batch-to-batch stability, failing to meet commercialization requirements. These problems urgently need to be addressed. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention proposes a mosquito repellent composition containing plant-derived synergists and its application. The mosquito repellent composition proposed in this invention can effectively control resistant mosquitoes and delay the occurrence and development of drug resistance; at the same time, it effectively reduces the dosage of insecticides and further improves safety.

[0008] The first object of the present invention is to provide a mosquito repellent composition containing a plant-derived synergist, comprising the plant-derived synergist and a fluorinated pyrethroid, wherein the plant-derived synergist is β-caryophyllene, a mixture of β-caryophyllene and α-terpineol, or a mixture of β-caryophyllene and citronellol.

[0009] This invention starts with plant essential oils and screens plant-derived compounds (i.e., plant-derived synergists) that have repellent activity against mosquitoes and can inhibit the activity of detoxification and metabolic enzymes in their bodies. The mosquito-repellent composition proposed in this invention contains plant-derived compounds and fluorinated pyrethroids (e.g., tetrafluoromethrin). The plant-derived compounds have the dual effects of inhibiting the activity of detoxification and metabolic enzymes in insects and repelling them, thereby synergizing tetrafluoromethrin with mosquitoes and improving the insecticidal activity of the insecticide. Its effect is significantly enhanced compared with tetrafluoromethrin alone, which can effectively control resistant pests and delay the occurrence and development of resistance; moreover, it effectively reduces the dosage of insecticide used and further improves safety.

[0010] Preferably, the mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 1-100:1.

[0011] Further preferred, the mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 1-50:1.

[0012] In a further preferred embodiment, the mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 20:1.

[0013] Preferably, the mass ratio of β-caryophyllene to α-terpineol in the mixture of β-caryophyllene and α-terpineol is 1:1, and the mass ratio of β-caryophyllene to citronellol in the mixture of β-caryophyllene and citronellol is 1:1.

[0014] Preferably, the fluorinated pyrethroid is tetrafluoromethrin.

[0015] A second objective of this invention is to provide the use of the aforementioned mosquito-repellent composition in the preparation of pesticide formulations.

[0016] Preferably, the formulation of the mosquito repellent includes mosquito coils, electric mosquito repellent liquids, electric mosquito repellent tablets, and aerosols.

[0017] When the mosquito repellent formulation is in the form of mosquito coils, the liquid is prepared according to the following mass ratio: 2.4% tetramethrin, 2.4%-48% plant-derived synergist, and the remainder is solvent oil. After mixing, the mosquito coil liquid is obtained. The mosquito coil liquid is evenly sprayed onto a conventional mosquito coil blank until the liquid is completely absorbed into the blank to obtain tetramethrin mosquito coil. The mass fraction of the mosquito repellent composition in the mosquito coil is 0.06%-0.63%.

[0018] A third object of the present invention is to provide a pesticide formulation comprising the aforementioned mosquito-repellent composition and pesticide-acceptable excipients. The mosquito species referred to in this invention is Culex quinquefasciatus.

[0019] Preferably, the mass fraction of the mosquito-repellent composition in the pesticide formulation is 0.01%-20%.

[0020] Further preferably, the mass fraction of the mosquito-repellent composition in the pesticide formulation is 0.06%-1.56%.

[0021] Further preferred, the mass fraction of the mosquito repellent and killing composition in the electric mosquito repellent liquid is 1.04%-1.56%.

[0022] Compared with the prior art, the present invention has the following advantages: 1. The mosquito repellent composition proposed in this invention significantly enhances the efficacy of plant-derived synergists and fluorinated pyrethroids (e.g., tetrafluoromethrin) when formulated in a specific ratio, reducing the amount of pesticide used and effectively preventing mosquito pests that have developed resistance to existing pyrethroid pesticides.

[0023] 2. The mosquito repellent composition proposed in this invention has the dual effects of inhibiting the activity of detoxification and metabolic enzymes in insects and mosquito-repelling activity. While targeting insect metabolic resistance, it enhances the repellent effect of pyrethroid active ingredients on mosquitoes, which is beneficial to overcoming and delaying the development of pesticide resistance in pests and extending the service life of the pesticide.

[0024] 3. The plant-derived synergist components proposed in this invention are plant-based, possessing advantages such as low toxicity, low susceptibility to drug resistance, and environmental friendliness. Detailed Implementation

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0026] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental materials and reagents used herein are commercially available products conventionally available in this technical field.

[0027] Experimental Example 1 Effects of plant-derived synergists (plant-derived compounds) on the activity of detoxification and metabolic enzymes in Culex pipiens quinquefolius To analyze the effects of plant-derived compounds on the detoxification metabolic enzyme activity of *Culex pipiens quinquefolius*, three plant-derived compounds—β-caryophyllene, α-terpineol, and citronellol—were prepared into 10% (v / v) acetone solutions: β-caryophyllene in acetone, α-terpineol in acetone, and citronellol in acetone. Five days after feeding, female *Culex pipiens quinquefolius* mosquitoes were anesthetized with ether. 0.5 µL of each of these acetone solutions was then added dropwise to the abdomen of the mosquitoes. A control group received only acetone. After the acetone had completely evaporated, the treated female *Culex pipiens quinquefolius* mosquitoes were transferred to clean plastic containers for normal rearing. Twenty-four hours later, each treated female *Culex pipiens quinquefolius* mosquito was stored in liquid nitrogen for protein and enzyme activity analysis. Frozen Culex quinquefolia female mosquitoes were homogenized in 1 mL of pH 7.2 (5 mM) PBS solution, centrifuged at 14000 rpm for 10 min at 4 °C, and the supernatant was collected. Total protein content determination and corresponding enzyme activity assay kits (product codes: A045-3-1, H677-1-2, A004-1-1, H529-1-2, A133-1-1, respectively) were purchased from Nanjing Jiancheng Biotechnology Co., Ltd. The total protein content in *Culex pipiens quinquefolius* treated with the compound and the activities of four detoxification metabolic enzymes closely related to pyrethroid resistance were determined. The assay methods were based on the kit instructions and the results of Zhu J, Lai Y, Wu Y, et al. Insecticidal activity of essential oils and their synergistic effect on improving the efficacy of β-cypermethrin against *Blattella germanica* [J]. Journal of Agricultural and Food Chemistry, 2024, 72(18): 10295-10303.

[0028] Each treatment was performed in triplicate, with 10 female mosquitoes per replicate. The test results are shown in Table 1. Table 1

[0029] As shown in Table 1 above, β-caryophyllene can significantly reduce the activity of CYP450, AChE and CarE in Culex pipiens quinquefolius, while α-terpineol has a significant inhibitory effect on the activity of CYP450 and GST, and citronellol only has a significant inhibitory effect on CYP450.

[0030] Tests on the repellent activity of plant-derived compounds against Culex pipiens quinquefolius The repellent activity of plant-derived compounds against Culex pipiens quinquefolius was determined using a Y-shaped olfactory instrument (arms 20 cm long, angle 75°, inner diameter 3 cm). The experiment was conducted under dim lighting conditions (ambient temperature 26±1℃, relative humidity 60±5%). Twenty female mosquitoes that had not fed for five days were cryo-anesthetized at 4℃ for approximately 2-3 minutes. After the mosquitoes were rendered unconscious, they were quickly transferred to a temporary buffer room. The mosquitoes were allowed to recover for 10 minutes under dim red light. Recovery was defined as the mosquitoes being able to fly and climb normally. The experiment was conducted after all mosquitoes had fully recovered. Three plant-derived compounds, β-caryophyllene, α-terpineol, and citronellol, were prepared into 10% (v / v) acetone solutions of β-caryophyllene, α-terpineol, and citronellol. 10 μL of each plant-derived compound solution or acetone was dropped onto 20 mm × 20 mm filter paper and quickly placed into the sample chamber of a Y-tube. Blank filter paper was placed on the other side of the Y-tube as a control. After placing the sample, the filtration device was quickly turned on, with a gas flow rate of 0.5 L / min. The buffer chamber valve was opened, and timing was started. The number of mosquitoes entering the two arms (control arm and sample arm) of the Y-tube was recorded at 10 min and 20 min. After each experiment, the tube was ventilated for 1 h to dissipate odor, and the filter paper was replaced. Each compound treatment was repeated 3 times, with 20 new mosquitoes used each time. The percentage repellency (PR) was calculated using the following formula (1): (1)

[0031] In the formula, Nc represents the number of mosquitoes in the control arm; Nt represents the number of mosquitoes in the sample arm.

[0032] The results of the approach-avoidance rate test are shown in Table 2: Table 2

[0033] Y-type olfactometer test determined the repellent activity of three plant-derived compounds against Culex pipiens quinquefolius. As can be seen from the results in Table 2, all three plant-derived compounds have good repellent activity against Culex pipiens quinquefolius.

[0034] Insecticidal activity assay of tetrafluoromethrin against mosquitoes First, tetrafluoromethrin was prepared into a series of stock solutions using acetone. Each stock solution was then evenly dropped onto the bottom surface of a 90 mm diameter glass culture dish. The dish was tilted and rotated to ensure the solution covered the entire bottom surface. The dish was left uncovered for 3-4 hours to allow the acetone to completely evaporate, resulting in the following unit area doses on the culture dish surface: 49.06, 98.13, 196.25, 392.50, and 785.00 μg / m² (based on the surface area of ​​the culture dish). Ten female adult mosquitoes were then cultured in each dish. To prevent escape, the dishes were covered. After 1 hour of exposure at room temperature, the mosquitoes were transferred to new disposable food containers and placed in a constant temperature (26 ± 2℃) and humidity (70 ± 5%) incubator. They were fed with a 10% sucrose solution, and mortality was measured after 24 hours. Each concentration was tested in triplicate, using the same batch of female mosquitoes in each replicate. A blank control was used as the control group. Concentrations were expressed in μg of insecticide per square meter of petri dish surface. The toxicity regression equation and LC-120 were calculated using SPSS 24.0 software. 20 Let X be the sample concentration (mg / L) after taking log10, and Y be the probability value of the corrected mortality rate. The toxicity regression equation for the tetrafluoromethrin sample is: Y = 0.774X - 1.791.

[0035] The LC50 of tetrafluoromethrin against mosquitoes was obtained. 20 = 79 μg / m 2 .

[0036] Plant-derived synergistic test In insecticide LC 20 Under these conditions, each compound was administered at 2 mg / m². 2 The concentration of tetrafluoromethrin (or two compounds in a 1:1 mass ratio) was used with tetrafluoromethrin to evaluate its synergistic effect. The method was consistent with the toxicity regression equation test method, with PBO as a positive control. The co-toxicity coefficient of the tetrafluoromethrin-plant-derived compound mixture was calculated by equation (2). If the co-toxicity coefficient was greater than 20, it was defined as an synergist. If the factor was less than -20, the essential oil was defined as an antagonist. If the factor was between 20 and -20, the essential oil was defined as purely additive (Norris, E., Johnson, J., Gross, A., Bartholomay, L., Coats, J., 2018. Plant essential oils enhance diverse pyrethroids against multiple strains of mosquitoes and inhibit detoxification enzyme processes. Insects 9, 132.).

[0037] (2) Note: Test mortality rate refers to the mortality rate caused by the pesticide-essential oil mixture. Predicted mortality rate refers to the mortality rate caused by the pesticide in LC. 20 The mortality rate at that time.

[0038] The test results are shown in Table 3: Table 3

[0039] Note: Syn. indicates a synergistic effect.

[0040] As can be seen from the results in Table 3, all three compounds have a certain synergistic effect on tetrafluoromethrin in Culex pipiens quinquefolius through direct contact, and the synergistic effect is more obvious in some of the compound combinations.

[0041] Example 1 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 100:1.

[0042] Example 2 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 50:1.

[0043] Example 3 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 20:1.

[0044] Example 4 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 1:1.

[0045] Example 5 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 1:2.

[0046] Example 6 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol or citronellol and tetrafluoromethrin in a mass ratio of 1:5.

[0047] Example 7 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, α-terpineol, and tetrafluoromethrin in a mass ratio of 10:10:1.

[0048] Example 8 A mosquito-killing composition containing a plant-derived synergist, comprising β-caryophyllene, citronellol, and tetrafluoromethrin in a mass ratio of 10:10:1.

[0049] Example 9 A mosquito-killing composition containing a plant-derived synergist is composed of α-terpineol, citronellol, and tetrafluoromethrin in a mass ratio of 10:10:1.

[0050] For ease of use, the mosquito-repellent composition proposed in this invention can be prepared into formulations suitable for agricultural use using known methods. In the following examples or comparative examples, the solvent oil is a dearomatic, odorless C12-C16 alkane solvent, the volatility regulator is dimethyl carbonate, and the antioxidant is butylated hydroxytoluene.

[0051] Example 10 Mosquito Coil 1 The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin, 48% β-caryophyllene, and 49.6% solvent oil. After mixing, the caryophyllene-tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a conventional mosquito repellent blank. After the liquid is completely absorbed into the blank, a 0.03% tetrafluoromethrin mosquito repellent (containing 0.6% β-caryophyllene) is obtained.

[0052] Example 11 Mosquito Coil 2 The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin, 4.8% β-caryophyllene, and 92.8% solvent oil. After mixing, the β-caryophyllene-tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a conventional mosquito repellent blank. After the liquid is completely absorbed into the blank, a 0.03% tetrafluoromethrin mosquito repellent (containing 0.06% β-caryophyllene) is obtained.

[0053] Example 12 Mosquito Coil 3 The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin, 2.4% β-caryophyllene, and 95.2% solvent oil. After mixing, the β-caryophyllene-tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a conventional mosquito repellent blank until the liquid is completely absorbed into the blank to obtain a 0.03% tetrafluoromethrin mosquito repellent (containing 0.03% β-caryophyllene).

[0054] Example 13 Mosquito Coil 4 The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin, 24% β-caryophyllene, 24% citronellol, and 49.6% solvent oil. After mixing, the β-caryophyllene-citronellol-tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a conventional mosquito repellent blank until the liquid is completely absorbed into the blank to obtain a 0.03% tetrafluoromethrin mosquito repellent (containing 0.3% β-caryophyllene and 0.3% citronellol).

[0055] Example 14 Mosquito Coil 4 The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin, 2.4% β-caryophyllene, 2.4% citronellol, and 92.8% solvent oil. After mixing, the β-caryophyllene-citronellol-tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a conventional mosquito repellent blank until the liquid is completely absorbed into the blank to obtain a 0.03% tetrafluoromethrin mosquito repellent (containing 0.03% β-caryophyllene and 0.03% citronellol).

[0056] Comparative Example 1: Mosquito Coil The mosquito repellent liquid is prepared according to the following mass ratio: 2.4% tetrafluoromethrin and 97.6% solvent oil. After mixing, a 2.4% tetrafluoromethrin mosquito repellent liquid is obtained. The mosquito repellent liquid is evenly sprayed onto a standard mosquito repellent coil blank. After the liquid is completely absorbed into the blank, a 0.03% tetrafluoromethrin mosquito repellent is obtained.

[0057] Example 15 Electric Mosquito Repellent Liquid 1 The electric mosquito repellent liquid is prepared according to the following mass ratio: tetrafluoromethrin 0.52%, β-caryophyllene 0.52%, volatility regulator 20%, antioxidant 0.5%, and solvent oil to 100%. The above raw materials are added to the mixing tank in the specified proportions, and the tank is sealed to reduce the time the liquid is exposed to air. The mixing device is then started. After the mixture is homogeneous, the discharge pipe valve is opened, and the liquid is discharged through the mixing tank's feed pipe to a storage tank with heating and insulation functions. The liquid in the storage tank is heated to 45℃-60℃ and kept at that temperature. The liquid in the storage tank is connected to the filling line via the feed pipe, and the liquid is quickly poured into mosquito repellent liquid bottles. The bottles are then sealed to produce the finished product, with a filling volume of 45 mL / bottle.

[0058] Example 16 Electric Mosquito Repellent Liquid 2 The electric mosquito repellent liquid is prepared according to the following mass ratio: tetrafluoromethrin 0.52%, β-caryophyllene 1.04%, volatility regulator 20%, antioxidant 0.5%, and solvent oil to 100%. The above raw materials are added to the mixing tank in the specified proportions, and the tank is sealed to reduce the time the liquid is exposed to air. The mixing device is then started. After the mixture is homogeneous, the discharge pipe valve is opened, and the liquid is discharged through the mixing tank's feed pipe to a storage tank with heating and insulation functions. The liquid in the storage tank is heated to 45-60℃ and kept at that temperature. The liquid in the storage tank is connected to the filling line via the feed pipe, and the liquid is quickly poured into mosquito repellent liquid bottles. The bottles are then sealed to produce the finished product, with a filling volume of 45 mL / bottle.

[0059] Example 17 Electric Mosquito Repellent Liquid 3 The electric mosquito repellent liquid is prepared according to the following mass ratio: tetrafluoromethrin 0.52%, β-caryophyllene 0.52%, citronellol 0.52%, volatility regulator 20%, antioxidant 0.5%, and solvent oil to 100%. The above raw materials are added to the mixing tank in the specified proportions, and the tank is sealed to reduce the time the liquid is exposed to air. The mixing device is then started. After the mixture is homogeneous, the discharge pipe valve is opened, and the liquid is discharged through the mixing tank's feed pipe to a storage tank with heating and insulation functions. The liquid in the storage tank is heated to 45-60℃ and kept at that temperature. The liquid in the storage tank is connected to the filling line via the feed pipe, and the liquid is quickly poured into mosquito repellent liquid bottles. The bottles are then sealed to produce the finished product, with a filling volume of 45 mL / bottle.

[0060] Comparative Example 2: Electric Mosquito Repellent Liquid The electric mosquito repellent liquid is prepared according to the following mass ratio: tetrafluoromethrin: 0.52%, volatility regulator: 20%, antioxidant: 0.5%, and solvent oil to 100%. The above raw materials are added to the mixing tank in the specified proportions. The mixing tank is sealed to reduce the time the liquid is exposed to air. The mixing device is then started. After the mixture is homogeneous, the discharge pipe valve is opened, and the liquid is discharged through the mixing tank's feed pipe to a storage tank with heating and insulation functions. The liquid in the storage tank is heated to 45-60℃ and kept at that temperature. The liquid in the storage tank is connected to the filling line via the feed pipe, and the liquid is quickly poured into mosquito repellent liquid bottles. The bottles are sealed to produce the finished product, with a filling volume of 45 mL / bottle.

[0061] The essential oils mentioned above were purchased from Guangzhou Fuling Biotechnology Co., Ltd.

[0062] To better illustrate the technical advantages of the technical solution provided by this invention, experimental test data of the composition provided in this application are given below: Experiment 1: Determination of the toxicity of plant-derived compounds in combination with tetrafluoromethrin (Examples 1-9) to Culex pipiens quinquefolius. Test insect: Culex pipiens quinquefolia The test method was the Tarsal test method. First, the toxicity of tetrafluoromethrin was measured using the LC50 assay. 20 The synergistic activity of the three plant-derived compounds and PBO was tested by combining their concentrations with those of the other three compounds alone. A concentration of 79 μg / m³ was selected for the combination. 2In the tetrafluoromethrin test, tetrafluoromethrin, β-caryophyllene, α-terpineol, and citronellol were used as controls. The test samples were evenly spread on petri dishes. After the solvents had completely evaporated, the dishes were covered, and 10 non-blood-sucking mosquitoes were transferred to the petri dishes using a mosquito aspirator. One hour after the exposure, the number of mosquitoes knocked down and killed was recorded. The mosquitoes were then transferred to disposable containers and placed in a 10% sucrose solution. The mortality rate was observed after 24 hours of incubation at 26℃±2℃ and 70%±5% relative humidity. The toxicity regression equation for the samples was calculated using SPSS 24.0 software. A mixture of toxicity factors with a value greater than 20 was defined as having a synergistic effect, and a value less than 20 was defined as having an antagonistic effect. The co-toxicity coefficient was calculated as (actual mortality rate - theoretical mortality rate) / theoretical mortality rate. The toxicity test results are shown in Table 4 below. Table 4

[0063] Table 4 shows that when β-caryophyllene, α-terpineol, citronellol, and tetrafluoromethrin are within a specific ratio range, the pesticide composition has a significant synergistic effect on the tested pests. Among them, when β-caryophyllene and tetrafluoromethrin are combined at a mass ratio of 20:1, the mortality rate is 56.67% and the co-toxicity coefficient is 183.65, showing a strong synergistic effect. In particular, when the mass ratio of β-caryophyllene, citronellol, and tetrafluoromethrin is 10:10:1, the mortality rate reaches 60.00% and the co-toxicity coefficient is 200.00, with a more obvious synergistic effect, which is significantly higher than the insecticidal activity of tetrafluoromethrin alone and each plant-derived component used alone.

[0064] Examples 10-14 and Comparative Example 1 were tested for bioefficacy against Culex pipiens quinquefolius according to the method specified in the national standard GB / T 13917.4-2025 "Indoor Efficacy Tests and Evaluation of Sanitary Insecticides for Pesticide Registration - Part 4: Mosquito Coils". The results are shown in Table 5 below. Table 5

[0065] Examples 15-17 and Comparative Example 2 were conducted on the bioefficacy of Culex pipiens quinquefolius according to the methods outlined in the national standard GB / T 13917.6-2009 "Indoor Efficacy Tests and Evaluation of Sanitary Insecticides for Pesticide Registration Part 6: Electric Mosquito Repellent Liquid". The results are shown in Table 6 below. Table 6

[0066] The comparison between the above examples and the comparative examples shows that the addition of plant-derived synergists can improve the bioefficacy of tetrafluoromethrin against mosquitoes in both mosquito coils and electric mosquito repellent liquids, which are the two most commonly used household mosquito repellent products. This indicates that plant-derived synergists also show a significant synergistic effect on tetrafluoromethrin in practical applications.

[0067] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A mosquito repellent composition containing a plant-derived synergist, characterized in that, It includes plant-derived synergists and fluorinated pyrethroids, wherein the plant-derived synergists are β-caryophyllene, a mixture of β-caryophyllene and α-terpineol, or a mixture of β-caryophyllene and citronellol.

2. The mosquito repellent composition according to claim 1, characterized in that, The mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 1-100:

1.

3. The mosquito repellent composition according to claim 2, characterized in that, The mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 1-50:

1.

4. The mosquito repellent composition according to claim 3, characterized in that, The mass ratio of the plant-derived synergist to the fluorinated pyrethroid is 20:

1.

5. The mosquito repellent composition according to any one of claims 1-4, characterized in that, In the mixture of β-caryophyllene and α-terpineol, the mass ratio of β-caryophyllene to α-terpineol is 1:1, and in the mixture of β-caryophyllene and citronellol, the mass ratio of β-caryophyllene to citronellol is 1:

1.

6. The mosquito repellent composition according to any one of claims 1-4, characterized in that, The fluorinated pyrethroid mentioned is tetrafluoromethrin.

7. The use of the mosquito-repellent composition according to any one of claims 1-4 in the preparation of pesticide formulations.

8. The application according to claim 7, characterized in that, The formulations of the pesticides mentioned include mosquito coils, electric mosquito repellent liquids, electric mosquito repellent tablets, and aerosols.

9. A pesticide formulation, characterized in that, Includes the mosquito repellent composition according to any one of claims 1-4 and pesticide-acceptable excipients.

10. The pesticide formulation according to claim 9, characterized in that, The mass fraction of the mosquito-repellent composition in the pesticide formulation is 0.01%-20%.

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