A complex plant source insect repellent and a preparation method thereof

Abstract

The present application relates to a kind of complex plant source insect repellent and its preparation method, belong to the field of agricultural chemistry, to solve the existing drug resistance, residual, stability and poor rain scouring resistance and other problems of insect repellent.The insect repellent is low-dose non-porony as the core, with three kinds of natural repellents of mint, citronella, garlic extract, contains wormwood powder, neem leaf powder, clove powder, compound plant fermentation extract fermented by bacillus subtilis, supplemented with specific emulsifier, stabilizer, synergist, deionized water is made up to 100 parts.Preparation is dissolved, mixed, emulsified, homogenized, screened and filled.The present application has broad-spectrum insect repellent and low drug resistance, good storage stability, effective ingredients are not easy to decompose, strong rain scouring resistance, low crop residue and environmental protection, simple and controllable preparation process, suitable for vegetables, food, fruit trees and other crops, can prevent and control a variety of pests, easy to industrial production.

Description

Technical Field

[0001] This invention belongs to the field of agrochemical technology and relates to a compound plant-derived insect repellent and its preparation method. Background Technology

[0002] With the large-scale development of modern agriculture, pest control has become a crucial link in ensuring crop yield and quality. Currently, insect repellents on the market are mainly divided into two categories: chemical insect repellents and plant-derived insect repellents.

[0003] Chemical insect repellents are widely used due to their rapid action and strong insecticidal effect. However, traditional chemical insect repellents have many drawbacks: First, in pursuit of long-lasting effects, high doses of active ingredients (such as high concentrations of fipronil and chlorantraniliprole) are often used. Long-term use can easily lead to serious resistance in pests, causing the insecticidal effect to decline year by year, requiring continuous increases in dosage, creating a vicious cycle. Second, high doses of chemical components are prone to residues on crop surfaces and in soil. Excessive residues can harm human health and pollute the soil, water sources, and other ecological environments. Third, the active ingredients in chemical insect repellents are mostly synthetic compounds, which are easily decomposed during storage due to environmental factors such as temperature and humidity, leading to reduced efficacy and poor storage stability. Fourth, chemical insect repellents have poor adhesion to crop surfaces, and are easily washed away by rain after application, resulting in insufficient efficacy and requiring frequent reapplication, increasing planting costs and environmental pressure.

[0004] Plant-derived insect repellents, with natural plant extracts as their main components, have advantages such as being environmentally friendly, having low residues, and being safe for non-target organisms. However, they also have significant drawbacks: First, the insecticidal spectrum of a single plant-derived ingredient is relatively narrow, making it difficult to achieve broad-spectrum control. Second, the duration of efficacy is short, typically decreasing significantly within 3-5 days after application, and its resistance to rain washout is extremely poor, rendering it almost completely ineffective after rain. Third, the activity of plant-derived ingredients is easily affected by the external environment, and they are prone to oxidation and degradation during storage, requiring improvements in storage stability. Fourth, some plant-derived insect repellents have weak insecticidal activity, requiring large quantities to achieve the desired effect, which also increases the cost of application.

[0005] To address these issues, existing technologies attempt to combine chemical insecticides with plant-derived ingredients, but key technical bottlenecks remain: First, the synergistic effect between the active ingredients after compounding is not obvious, and even antagonistic effects occur, making it difficult to balance broad-spectrum and long-lasting effects; second, the core issues of rain resistance and storage stability have not been resolved, and most compound formulations still suffer from poor adhesion and easy decomposition of active ingredients; third, the risk of drug resistance is poorly controlled, and some compound formulations still rely on high doses of chemical components, failing to fundamentally reduce the probability of pesticide resistance in pests.

[0006] Based on this, the development of a compound plant-derived insect repellent with low-dose chemical components as the core, combined with natural repellents and specific compound plant fermentation extracts, to achieve broad-spectrum insect repellency, low risk of drug resistance, high storage stability and strong resistance to rain washout, has become an urgent technical need to be addressed in the current agrochemical field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a compound plant-derived insect repellent and its preparation method. The insect repellent uses low-dose fipronil as the core component, combined with a variety of natural repellents and compound plant fermentation extracts to achieve broad-spectrum insect repellency. At the same time, it significantly improves storage stability and residual time on crops after application, has strong resistance to rain washout, and can effectively reduce the risk of pest resistance, taking into account both environmental protection and practicality.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A compound plant-derived insect repellent, comprising the following components in parts by weight: 0.1-0.5 parts of the core active ingredient fipronil;

[0010] Natural repellent: 1-3 parts peppermint extract, 2-4 parts lemongrass extract, 0.5-1.5 parts garlic extract;

[0011] 6-12 parts of compound plant fermentation extract;

[0012] Additives: 1.5-2.5 parts emulsifier, 0.3-0.7 parts stabilizer, and 0.6-1.4 parts synergist;

[0013] Add deionized water to bring the total to 100 parts;

[0014] The compound plant fermentation extract is prepared by fermentation of Artemisia argyi powder, Neem leaf powder and clove powder using Bacillus subtilis.

[0015] As a preferred embodiment of the present invention, the amount of fipronil by weight is 0.2-0.4 parts.

[0016] As a preferred embodiment of the present invention, the natural repellent comprises the following components by weight: 1.5-2.5 parts peppermint extract, 2.5-3.5 parts lemongrass extract, and 0.8-1.2 parts garlic extract.

[0017] As a preferred technical solution of the present invention, the compound plant fermentation extract contains artemisia powder, neem leaf powder and clove powder in a compound mass ratio of (4-6):(2-4):(1-3), preferably 5:3:2.

[0018] As a preferred embodiment of the present invention, the preparation steps of the compound plant fermentation extract include:

[0019] W1. Dry the mugwort, neem leaves, and cloves separately until the moisture content is less than or equal to 8%, pulverize them, and pass them through an 80-mesh sieve to obtain the corresponding powders;

[0020] W2. Weigh out the three powders according to the proportion, mix them at 300r / min for 20 minutes to obtain the compound plant powder;

[0021] W3. Add deionized water to the compound plant powder, adjust the solid-liquid ratio to 1:(8-12), sterilize, and then cool to 28-32℃;

[0022] W4. Inject at a concentration of 5%-8% (volume fraction) of 1×10⁻⁶. 8 CFU / mL Bacillus subtilis culture, adjusted to pH 6.0-7.0, fermented at 28-32℃ and 180r / min for 60-84 hours;

[0023] W5. Centrifuge the fermentation broth to collect the supernatant, and concentrate it under reduced pressure to a solid content of 15%-25% to obtain a compound plant fermentation extract.

[0024] As a preferred embodiment of the present invention, the solid-liquid ratio in step W3 is 1:10, and the sterilization conditions are 121°C and 0.1MPa for 20 minutes.

[0025] In step W4, the inoculum size was 6%, the fermentation temperature was 30℃, the pH value was 6.5, the fermentation time was 72 hours, and the mixture was stirred for 10 minutes every 12 hours during the fermentation process.

[0026] As a preferred embodiment of the present invention, the emulsifier is polyoxyethylene sorbitan monooleate, the stabilizer is xanthan gum, and the synergist is alkyl glycoside.

[0027] The mass fractions of the additives are: 1.8-2.2 parts emulsifier, 0.4-0.6 parts stabilizer, and 0.8-1.2 parts synergist.

[0028] As a preferred embodiment of the present invention, the insect repellent is applicable to vegetables, grains, and fruit trees, and can control at least one of the following pests: aphids, cabbage caterpillars, spider mites, rice planthoppers, thrips, flea beetles, white grubs, and root-knot nematodes.

[0029] As a preferred technical solution of the present invention, after 12 months of storage at room temperature, the retention rate of effective ingredients is greater than or equal to 88%, and after application and simulated rainfall of 20 mm / h for 30 minutes, the residual rate of effective ingredients on the crop surface is ≥80%.

[0030] A method for preparing the above-mentioned plant-derived insect repellent includes the following steps:

[0031] X1. Weigh out fipronil, add 5-10 parts by weight of anhydrous ethanol, stir until completely dissolved, and obtain fipronil ethanol solution;

[0032] X2. Add the natural repellent to the fipronil ethanol solution, stir at 50°C and 500 r / min for 30 minutes, then add the compound plant fermentation extract and continue stirring for 40 minutes to obtain mixture A;

[0033] X3. Add emulsifier, stabilizer and synergist to mixture A in sequence, stir at 60℃ and 800r / min for 60 minutes to obtain mixture B;

[0034] X4. Add the remaining deionized water to mixture B, stir well, and then homogenize at 8000-10000 r / min for 15-20 minutes to obtain an emulsion;

[0035] X5. Cool the emulsion to room temperature, pass it through a 200-mesh sieve, and then aseptically fill it to obtain the finished plant-derived insect repellent.

[0036] The beneficial effects of this invention are:

[0037] (1) With low-dose fipronil as the core, combined with three natural repellents: peppermint extract, lemongrass extract, and garlic extract, fipronil exerts its insecticidal effect on the nervous system of pests, while the natural repellents achieve their repellent effect through odor and contact stimulation. The combination of the two has a good control effect on more than 10 kinds of pests such as aphids, cabbage caterpillars, carmine spider mites, and rice planthoppers, with a corrected mortality rate of over 85% and a pest population reduction rate that remains above 70% for more than 14 days. Fipronil is designed with a low dose and works synergistically with the three natural repellents, avoiding the rapid development of pesticide resistance caused by a single high-dose component. After continuous use on 5 generations of pests, the resistance ratio is only 0.7-0.9.

[0038] (2) The Bacillus subtilis metabolites in the compound plant fermentation extract can effectively inhibit the oxidation and decomposition of fipronil and natural repellents. After 12 months of storage at room temperature, the retention rate of active ingredients reaches 88%-92%, with no layering or precipitation in appearance and a viscosity change rate of only 5%-7%. In addition, the active ingredients in the compound plant fermentation extract have good adhesion, which can enhance the binding force between the formulation and the surface of crop leaves. After application, when washed by rain (simulated rainfall of 20 mm / h for 30 minutes), the residual rate of active ingredients on the crop surface reaches 80%-88%, which significantly prolongs the duration of efficacy and reduces the number of reapplications.

[0039] (3) The dosage of fipronil is low, and both the compound plant fermentation extract and the natural repellent are of natural origin and are easily degradable. The residual amount of fipronil at crop harvest is <0.01mg / kg, which meets the national food safety standards and has no significant impact on the ecological environment such as soil and water. In addition, the preparation process is simple and controllable. The preparation process parameters of the compound plant fermentation extract are clear, the fermentation conditions are mild, and it is easy to scale up to industrial scale. The preparation process of the insect repellent does not require complex equipment. The homogenization emulsification step can ensure the uniformity and stability of the formulation and the product quality is controllable. Detailed Implementation

[0040] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0041] Sources of some raw materials:

[0042] Peppermint Extract: Peptide Biotechnology (Shanxi) Co., Ltd.

[0043] Lemongrass extract: Shanxi Kangrui Kesheng Biotechnology Co., Ltd.

[0044] Garlic extract: Shanxi Hetai Biotechnology Co., Ltd.

[0045] Polyoxyethylene sorbitan monooleate: Shandong Gushuo Biotechnology Co., Ltd.

[0046] Xanthan Gum: Anhui Anrui Biotechnology Co., Ltd.

[0047] Alkyl glycosides: Henan Xiangfa Chemical Products Co., Ltd.

[0048] Bacillus subtilis: CICC®10732

[0049] Saccharomyces cerevisiae: CICC®1001

[0050] Artemisia argyi extract: Huarui Biotechnology (Shanxi) Co., Ltd.

[0051] Azadirachtin: Shaanxi Haochen Biotechnology Co., Ltd.

[0052] Clove extract: Shanxi Xinghe Biotechnology Co., Ltd.

[0053] Example 1

[0054] A compound plant-derived insect repellent, comprising the following components in parts by weight:

[0055] 0.3 parts fipronil;

[0056] Peppermint extract 2.0 parts, lemongrass extract 3.0 parts, garlic extract 1.0 part;

[0057] Eight portions of compound plant fermentation extract;

[0058] Polyoxyethylene sorbitan monooleate 2.0 parts, xanthan gum 0.5 parts, alkyl glycoside 1.0 parts;

[0059] 84.2 parts of deionized water.

[0060] Among them, the preparation of compound plant fermentation extract:

[0061] Plant raw material pretreatment: Artemisia argyi, neem leaves and cloves are dried to a moisture content of ≤8%, pulverized and passed through an 80-mesh sieve to obtain Artemisia argyi powder, neem leaves powder and clove powder;

[0062] Compound mixing: Weigh out the ingredients according to the mass ratio of Artemisia argyi powder: Melia azedarach leaf powder: Clove powder = 5:3:2, mix at 300 r / min for 20 minutes to obtain compound plant powder;

[0063] Fermentation substrate preparation: Add deionized water to the compound plant powder, with a solid-liquid ratio of 1:10, stir evenly, sterilize at 121℃ for 20 minutes, and cool to 30℃;

[0064] Inoculation fermentation: Inoculate with 6% (volume fraction) concentration 1×10 8 Bacillus subtilis culture solution with CFU / mL was adjusted to pH=6.5 and fermented on a shaker at 30℃ and 180r / min for 72 hours, with stirring for 10 minutes every 12 hours.

[0065] Post-processing: The fermentation broth was centrifuged at 8000 r / min for 20 minutes, and the supernatant was concentrated under reduced pressure (0.08 MPa, 50℃) to a solid content of 20% to obtain a compound plant fermentation extract.

[0066] The preparation method of this insect repellent:

[0067] Weigh 0.3 parts of fipronil, add 8 parts of anhydrous ethanol, and stir until completely dissolved to obtain a fipronil ethanol solution;

[0068] Add 2.0 parts of peppermint extract, 3.0 parts of lemongrass extract, and 1.0 part of garlic extract to the fipronil ethanol solution, stir at 50℃ and 500r / min for 30 minutes, then add 8 parts of compound plant fermentation extract, and continue stirring for 40 minutes to obtain mixture A;

[0069] Add 2.0 parts of polyoxyethylene sorbitan monooleate, 0.5 parts of xanthan gum, and 1.0 part of alkyl glycoside to mixture A, and stir at 60°C and 800 r / min for 60 minutes to obtain mixture B;

[0070] Add 84.2 parts of deionized water to mixture B, stir well, and then transfer to a high-pressure homogenizer. Homogenize at 9000 r / min for 18 minutes to obtain an emulsion.

[0071] Cool to room temperature, pass through a 200-mesh sieve, and aseptically fill to obtain the finished product.

[0072] Example 2

[0073] A compound plant-derived insect repellent, comprising the following components in parts by weight:

[0074] 0.2 parts fipronil;

[0075] Peppermint extract 1.5 parts, lemongrass extract 2.5 parts, garlic extract 0.8 parts;

[0076] 10 parts of compound plant fermentation extract;

[0077] 1.8 parts of polyoxyethylene sorbitan monooleate, 0.4 parts of xanthan gum, and 0.8 parts of alkyl glycoside;

[0078] 82.2 parts of deionized water.

[0079] The preparation process of the compound plant fermentation extract is the same as that in Example 1 (Artemisia argyi powder: Melia azedarach leaf powder: Clove powder = 5:3:2, solid-liquid ratio 1:10, inoculum amount 6%, fermentation at 30℃ and pH 6.5 for 72 hours, and concentration to a solid content of 20%).

[0080] The preparation method of this insect repellent:

[0081] Weigh 0.2 parts of fipronil, add 6 parts of anhydrous ethanol, and stir until completely dissolved to obtain a fipronil ethanol solution;

[0082] Add 1.5 parts peppermint extract, 2.5 parts lemongrass extract, and 0.8 parts garlic extract to the fipronil ethanol solution, stir at 50℃ and 500r / min for 30 minutes, then add 10 parts of compound plant fermentation extract, and continue stirring for 40 minutes to obtain mixture A;

[0083] Add 1.8 parts of polyoxyethylene sorbitan monooleate, 0.4 parts of xanthan gum, and 0.8 parts of alkyl glycoside to mixture A, and stir at 60°C and 800 r / min for 60 minutes to obtain mixture B;

[0084] Add 82.2 parts of deionized water to mixture B, stir well, and then transfer to a high-pressure homogenizer. Homogenize at 8000 r / min for 20 minutes to obtain an emulsion.

[0085] Cool to room temperature, pass through a 200-mesh sieve, and aseptically fill to obtain the finished product.

[0086] Example 3

[0087] A compound plant-derived insect repellent, comprising the following components in parts by weight:

[0088] 0.4 parts fipronil;

[0089] Peppermint extract 2.5 parts, lemongrass extract 3.5 parts, garlic extract 1.2 parts;

[0090] Six portions of compound plant fermentation extract;

[0091] Polyoxyethylene sorbitan monooleate 2.2 parts, xanthan gum 0.6 parts, alkyl glycoside 1.2 parts;

[0092] 84.4 parts of deionized water.

[0093] The preparation process of the compound plant fermentation extract is the same as that in Example 1 (Artemisia argyi powder: Melia azedarach leaf powder: Clove powder = 5:3:2, solid-liquid ratio 1:10, inoculum amount 6%, fermentation at 30℃ and pH 6.5 for 72 hours, and concentration to a solid content of 20%).

[0094] The preparation method of this insect repellent:

[0095] Weigh 0.4 parts of fipronil, add 10 parts of anhydrous ethanol, and stir until completely dissolved to obtain a fipronil ethanol solution;

[0096] Add 2.5 parts peppermint extract, 3.5 parts lemongrass extract, and 1.2 parts garlic extract to the fipronil ethanol solution, stir at 50℃ and 500r / min for 30 minutes, then add 6 parts of compound plant fermentation extract, and continue stirring for 40 minutes to obtain mixture A;

[0097] Add 2.2 parts of polyoxyethylene sorbitan monooleate, 0.6 parts of xanthan gum, and 1.2 parts of alkyl glycoside to mixture A, and stir at 60°C and 800 r / min for 60 minutes to obtain mixture B;

[0098] Add 84.4 parts of deionized water to mixture B, stir well, and then transfer to a high-pressure homogenizer. Homogenize at 10,000 r / min for 15 minutes to obtain an emulsion.

[0099] Cool to room temperature, pass through a 200-mesh sieve, and aseptically fill to obtain the finished product.

[0100] Comparative Example 1

[0101] It does not contain compound plant fermentation extracts. Deionized water is added to make up to 100 parts. The remaining components and preparation steps are the same as in Example 1.

[0102] Comparative Example 2

[0103] The compound plant fermentation extract contains only Artemisia argyi powder and Melia azedarach leaf powder (mass ratio 5:5), without clove powder. The remaining components and preparation steps are as described in Example 1.

[0104] Comparative Example 3

[0105] The ratio of Artemisia argyi powder: Melia toosendan leaf powder: Clove powder in the compound plant fermentation extract is 3:3:4 (the ratio is changed). The other components and preparation steps are the same as in Example 1.

[0106] Comparative Example 4

[0107] The fermentation strain was replaced with Saccharomyces cerevisiae (other fermentation parameters remained unchanged), and the remaining components and preparation steps were the same as in Example 1.

[0108] Comparative Example 5

[0109] The amount of fipronil by weight is 1.0 part (high dose), and the remaining components and preparation steps are as described in Example 1.

[0110] Comparative Example 6

[0111] It does not contain natural repellents (no peppermint extract, lemongrass extract, or garlic extract are added), and the remaining components and preparation steps are as described in Example 1.

[0112] Comparative Example 7

[0113] The natural repellent contains only 5.0 parts of peppermint extract (a single natural repellent, with the same total mass as in Example 1), and the remaining components and preparation steps are the same as in Example 1.

[0114] Comparative Example 8

[0115] The compound plant fermented extract was replaced with an unfermented compound plant extract (a mixture of 8 parts Artemisia argyi extract: azadirachtin: clove extract = 5:3:2 was directly added), and the remaining components and preparation steps were the same as in Example 1.

[0116] Comparative Example 9

[0117] It does not contain stabilizers (xanthan gum), and the remaining components and preparation steps are the same as in Example 1.

[0118] Comparative Example 10

[0119] The compound plant fermentation extract was 3 parts by weight, and the remaining components and preparation steps were as described in Example 1.

[0120] Comparative Example 11

[0121] The core ingredient was replaced with 0.3 parts of chlorantraniliprole (instead of fepronil), and the remaining components and preparation steps were as described in Example 1.

[0122] Performance testing

[0123] 1. Storage stability testing

[0124] Sample processing: The finished products of each example and comparative example were sealed in brown glass bottles and stored in environments of room temperature (25±2℃), high temperature (40±2℃), and low temperature (0±2℃), respectively. Samples were taken for testing at 0 months, 3 months, 6 months, and 12 months, respectively.

[0125] Detection indicators and methods:

[0126] Retention rate of active ingredient: The content of fipronil was determined by high performance liquid chromatography (HPLC). The chromatographic column was a C18 column (4.6 mm × 250 mm, 5 μm), the mobile phase was methanol:water = 80:20 (volume ratio), the flow rate was 1.0 mL / min, the detection wavelength was 254 nm, the column temperature was 30 ℃, and the retention rate was calculated as (content after storage / initial content) × 100%.

[0127] Appearance: Observe whether the sample has layering, precipitation, or discoloration. Grading standards: Grade 1 (Excellent) - No layering, no precipitation, uniform color; Grade 2 (Good) - Slight layering, recovers after shaking; Grade 3 (Poor) - Obvious layering or precipitation, does not recover after shaking; Grade 4 (Very Poor) - Severe discoloration, clumping.

[0128] Viscosity change rate: The viscosity was measured at 25°C using a rotational viscometer. The viscosity change rate was calculated as: |Viscosity after storage - Initial viscosity| / Initial viscosity × 100%.

[0129] 2. Rainwater runoff residue detection

[0130] Preparation of potted crops: Select cucumber seedlings with uniform growth (3 leaves and 1 heart stage), transplant them into flower pots with a diameter of 15cm, one seedling per pot, cultivate for 7 days and then use them. Each group of treatments has 3 pots replicated.

[0131] Application method: Use a backpack sprayer to spray each sample evenly at a dosage of 10 mL per plant. The control group was sprayed with an equal amount of deionized water.

[0132] Simulated rainfall: Two hours after pesticide application, simulated rainfall was applied to the crops using an artificial rainfall simulator (rainfall intensity 20 mm / h, rainfall duration 30 minutes). After the rainfall ended, the crops were allowed to air dry naturally for two hours.

[0133] Residue detection: Fipronil was extracted from the surface of crop leaves using solvent extraction. The specific steps were as follows: 0.5g of leaf was taken, 5mL of methanol was added, and the mixture was ultrasonically extracted for 30 minutes. After centrifugation at 8000r / min for 10 minutes, the supernatant was collected, and the content was detected by HPLC. The residue rate was calculated as (content after rainfall / content before rainfall) × 100% (content before rainfall was the detection value 2 hours after application and drying).

[0134] 3. Broad-spectrum insecticidal effect test

[0135] (1) Indoor toxicity testing

[0136] The tested pests were: aphids (Myzuspersicae), cabbage caterpillars (Pierisrapae), carmine spider mites (Tetranychuscinnabarinus), and rice planthoppers (Nilaparvatalugens). Sensitive strains were raised indoors, with the same instar (wingless adult aphids, 3rd instar larvae of cabbage caterpillars, adult spider mites, and 3rd instar nymphs of planthoppers).

[0137] Detection method: The leaf immersion method was used. Each sample was diluted to the field recommended concentration (1000 times dilution). Fresh leaves were immersed in the sample solution for 10 seconds, removed and dried, and then placed in a petri dish (9 cm in diameter). 20 test pests were placed in each dish. The experiment was repeated 3 times. The control group was soaked in deionized water.

[0138] Culture conditions: temperature 25±1℃, humidity 60±5%, light intensity 16L:8D;

[0139] Data recording: The number of dead insects was investigated after 48 hours, and the corrected mortality rate was calculated as follows: (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100%.

[0140] (2) Field plot experiment

[0141] Experimental sites: cucumber field (control of aphids and cabbage caterpillars), rice field (control of rice planthoppers), tomato field (control of spider mites);

[0142] The plot design was as follows: each plot had an area of ​​20m², and the randomized block design was used with 3 replicates. The control group was sprayed with an equal amount of deionized water.

[0143] Application method: Spray according to the recommended field dosage (150mL / mu, diluted with 30kg of water) at the initial stage of pest occurrence;

[0144] Data recording: Insect population density was investigated at 1, 3, 7 and 14 days after application of pesticide. The insect population reduction rate was calculated as (number of insects before application - number of insects after application) / number of insects before application × 100%.

[0145] 4. Drug resistance risk detection

[0146] Pest rearing: Aphids were used as the test subject. Each sample was prepared according to the LC50 (LC50) standard for indoor toxicity testing. 50 The pests were continuously treated with a concentration (median lethal concentration), and the surviving pests after each generation were continued to be raised to the next generation, for a total of 5 generations.

[0147] Detection method: The LC50 of the first and fifth generations of aphids was determined for each sample. 50 Value (HPLC combined with leaf immersion method), calculate the resistance ratio = 5th generation LC 50 / 1st generation LC 50 The smaller the ratio, the lower the risk of drug resistance (a ratio <1.0 indicates no significant drug resistance, 1.0-2.0 indicates low drug resistance, and >2.0 indicates high drug resistance).

[0148] 5. Residual content detection

[0149] Sample preparation: Cucumber fruits were collected 7 and 14 days after pesticide application in cucumber fields. The QuEChERS method was used for pretreatment: 10g of sample was taken, 20mL of acetonitrile was added, and the sample was extracted by vortexing for 1 minute. 4g of anhydrous magnesium sulfate and 1g of sodium chloride were added, and the sample was vortexed for 1 minute. After centrifugation at 8000r / min for 5 minutes, 2mL of supernatant was taken, 150mg of anhydrous magnesium sulfate and 50mg of PSA were added, and the sample was vortexed for 30 seconds. After centrifugation, the supernatant was filtered through a 0.22μm filter membrane.

[0150] Detection method: Fipronil residue was determined by HPLC, and the chromatographic conditions were the same as those for storage stability testing.

[0151] Performance test data

[0152] Table 1 Results of storage stability test at room temperature (25±2℃)

[0153]

[0154] Continued table

[0155]

[0156] Continued table

[0157]

[0158] Continued table

[0159]

[0160] Continued table

[0161]

[0162] Table 2 Results of Rainwater Erosion Residue Rate Test (Unit: %)

[0163] Sample number Fipronil content before rainfall (μg / g) Fipronil content (μg / g) after rainfall Residual rate (%) Example 1 2.56 2.25 87.9 Example 2 2.48 2.12 85.5 Example 3 2.62 2.09 80.0 Comparative Example 1 2.53 1.27 50.2 Comparative Example 2 2.51 1.78 70.9 Comparative Example 3 2.55 1.72 67.5 Comparative Example 4 2.50 1.65 66.0 Comparative Example 5 2.89 1.98 68.5 Comparative Example 6 2.54 1.75 68.9 Comparative Example 7 2.52 1.71 67.9 Comparative Example 8 2.49 1.53 61.4 Comparative Example 9 2.57 1.68 65.4 Comparative Example 10 2.53 1.58 62.5 Comparative Example 11 2.56 1.69 66.0

[0164] Table 3 Results of Indoor Toxicity Measurement (Unit: %)

[0165] Sample number aphid cabbage caterpillar Cinnabar Tetranychus Rice planthopper Mean corrected mortality rate Example 1 92.5 90.3 88.7 91.2 90.7 Example 2 91.8 89.5 87.6 90.5 89.8 Example 3 93.2 91.1 89.2 91.8 91.3 Comparative Example 1 85.6 83.2 80.5 84.1 83.3 Comparative Example 2 88.3 86.7 84.2 87.5 86.7 Comparative Example 3 87.8 85.9 83.6 86.9 86.1 Comparative Example 4 87.2 85.3 82.9 86.3 85.4 Comparative Example 5 94.1 92.5 90.8 93.2 92.7 Comparative Example 6 75.3 72.8 70.3 73.5 72.9 Comparative Example 7 82.5 80.1 78.3 81.2 80.5 Comparative Example 8 84.2 82.1 79.8 83.5 82.4 Comparative Example 9 86.5 84.3 82.1 85.7 84.7 Comparative Example 10 85.9 83.7 81.3 85.1 84.0 Comparative Example 11 90.5 88.7 86.9 89.8 89.0 control group 3.2 2.8 3.5 2.9 3.1

[0166] Table 4. Field pest reduction rate (aphids, cabbage caterpillars) in cucumber fields (unit: %)

[0167]

[0168] Table 5. Field pest reduction rate of rice planthoppers in paddy fields (unit: %)

[0169]

[0170] Table 6. Field pest reduction rate of *Tetranychus carmine* in tomato fields (unit: %)

[0171]

[0172] Table 7 Results of pesticide resistance testing after five consecutive generations of aphid treatment.

[0173]

[0174] Table 8. Results of fipronil residue detection in cucumber fruits (unit: mg / kg)

[0175]

[0176] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A compound plant-derived insect repellent, characterized in that, It consists of the following components in parts by weight: 0.1-0.5 parts of the core active ingredient, fipronil; Natural repellent: 1-3 parts peppermint extract, 2-4 parts lemongrass extract, 0.5-1.5 parts garlic extract; 6-12 parts of compound plant fermentation extract; Additives: 1.5-2.5 parts emulsifier, 0.3-0.7 parts stabilizer, and 0.6-1.4 parts synergist; Add deionized water to bring the total to 100 parts; The compound plant fermentation extract is prepared by fermentation of Artemisia argyi powder, Melia azedarach leaf powder and clove powder using Bacillus subtilis. In the compound plant fermentation extract, the mass ratio of mugwort powder, neem leaf powder, and clove powder is (4-6):(2-4):(1-3); The preparation steps of the compound plant fermentation extract include: W1. Dry the mugwort, neem leaves, and cloves separately until the moisture content is less than or equal to 8%, pulverize them, and pass them through an 80-mesh sieve to obtain the corresponding powders; W2. Weigh out the three powders according to the proportion, mix them at 300r / min for 20 minutes to obtain the compound plant powder; W3. Add deionized water to the compound plant powder, adjust the solid-liquid ratio to 1:(8-12), sterilize, and then cool to 28-32℃; W4. Access 5-8% volume fraction of Bacillus subtilis bacterial solution with 1 x 10 8 CFU / mL, adjust pH to 6.0-7.0, and ferment for 60-84 hours at 28-32°C and 180 r / min. W5. Centrifuge the fermentation broth to collect the supernatant, and concentrate it under reduced pressure to a solid content of 15%-25% to obtain a compound plant fermentation extract. The emulsifier is polyoxyethylene sorbitan monooleate, the stabilizer is xanthan gum, and the synergist is alkyl glycoside. The preparation method of the compound plant-derived insect repellent includes the following steps: X1. Weigh out fipronil, add 5-10 parts by weight of anhydrous ethanol, stir until completely dissolved, and obtain fipronil ethanol solution; X2. Add the natural repellent to the fipronil ethanol solution, stir at 50°C and 500 r / min for 30 minutes, then add the compound plant fermentation extract and continue stirring for 40 minutes to obtain mixture A; X3. Add emulsifier, stabilizer and synergist to mixture A in sequence, stir at 60℃ and 800r / min for 60 minutes to obtain mixture B; X4. Add the remaining deionized water to mixture B, stir well, and then homogenize at 8000-10000 r / min for 15-20 minutes to obtain an emulsion; X5. Cool the emulsion to room temperature, pass it through a 200-mesh sieve, and then aseptically fill it to obtain the finished plant-derived insect repellent.

2. The compound plant-derived insect repellent according to claim 1, characterized in that, In step W3, the solid-liquid ratio is 1:10, and the sterilization conditions are 121℃ and 0.1MPa for 20 minutes. In step W4, the inoculum size was 6%, the fermentation temperature was 30℃, the pH value was 6.5, the fermentation time was 72 hours, and the mixture was stirred for 10 minutes every 12 hours during the fermentation process.

3. The compound plant-derived insect repellent according to claim 1, characterized in that, The mass fractions of the additives are: 1.8-2.2 parts emulsifier, 0.4-0.6 parts stabilizer, and 0.8-1.2 parts synergist.

4. The compound plant-derived insect repellent according to claim 1, characterized in that, The amount of the nonprednisolone is 0.2-0.4 parts by weight.

5. The compound plant-derived insect repellent according to claim 1, characterized in that, The natural repellent contains the following components by weight: 1.5-2.5 parts peppermint extract, 2.5-3.5 parts lemongrass extract, and 0.8-1.2 parts garlic extract.

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