Preparation method of juglone microemulsion and insecticidal activity thereof

Abstract

This invention belongs to the field of plant-derived pesticide technology, specifically relating to a method for preparing a juglone microemulsion and its insecticidal activity. The juglone microemulsion comprises juglone, an oil phase, an emulsifier, a co-emulsifier, and water, with the following mass percentage composition: juglone: ​​2.5–10%, oil phase: 5–25%, emulsifier: 5–15%, co-emulsifier: 5–35%, and the balance being water. The mass ratio of the emulsifier to the co-emulsifier is 1:0.5–1:3. The juglone microemulsion of this invention uses plant-derived juglone as the main active ingredient. The prepared juglone microemulsion is an O / W type microemulsion, a clear, stable brown liquid, which can be diluted and directly sprayed onto the leaves of crops to kill and repel insects.

Description

Technical Field

[0001] This invention belongs to the field of plant-derived pesticide technology, specifically, it relates to a method for preparing a juglone microemulsion and its insecticidal activity. Background Technology

[0002] Numerous studies have shown that the green husk of walnut contains juglone, a chemical substance with biological activity against insects. Juglone's chemical name is 5-hydroxy-1,4-naphthoquinone, and its molecular formula is: C 10 H6O3, with a molecular weight of 174.16. This chemical substance can be used to control agricultural pests such as mites, aphids, and lepidopterans. It has contact, stomach poison, and growth-inhibiting effects on insects; it has good inhibitory effects on Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, and Staphylococcus epidermidis; and it has allelopathic effects on plants, inhibiting seed germination and growth.

[0003]

[0004] Pesticides, as a major agricultural input, play a vital role in controlling crop diseases, pests, and weeds and ensuring agricultural harvests. Although integrated pest management and the promotion and application of genetically modified crops have achieved great success, pesticides will remain irreplaceable for a considerable period. Traditional chemical pesticides typically require the addition of organic solvents such as benzene, toluene, xylene, methanol, and dimethylformamide. These solvents are highly volatile and toxic, posing extremely high risks during transportation, storage, and use. Most importantly, they pollute soil and aquatic environments, causing serious harm to mammals, aquatic organisms, and non-target organisms. For example, using 1 ton of 4.5% high-efficiency cypermethrin emulsifiable concentrate is equivalent to injecting 850 kilograms of xylene into the environment, demonstrating the severity of its environmental pollution. Therefore, these traditional pesticide formulations can no longer meet the increasingly stringent safety regulations, necessitating the vigorous development of environmentally friendly green pesticide formulations to adapt to current international environmental protection requirements.

[0005] Compared to conventional chemical pesticides, plant-derived pesticides have the advantages of being environmentally friendly, having diverse biological activities, being less likely to induce pesticide resistance in pests, and being relatively safe for non-target organisms. Their environmental friendliness is mainly due to the fact that plant-derived pesticides originate from nature, are more easily decomposed after application, and cause little or no pollution to the environment.

[0006] Microemulsions (ME) are clear, stable, and homogeneous dispersions that appear transparent or nearly transparent, formed by two mutually soluble or immiscible liquids. They are primarily composed of an oil phase, emulsifier, co-emulsifier, and aqueous phase mixed in a specific ratio, and microscopically consist of microdroplets stabilized by surfactant interfacial films. Microemulsions can be classified into three types based on their structure: W / O, O / W, and bidirectional continuous.

[0007] Microemulsion pesticides have excellent solubilizing effects on poorly soluble pesticides, which can increase the pesticide loading and improve the drug dispersion. Compared with traditional emulsions, they can significantly reduce the amount of pesticide used. Furthermore, due to their stability, ease of storage, and low surface tension, microemulsion pesticides have excellent leaf spreadability. Therefore, microemulsion pesticides are receiving increasing attention.

[0008] However, the solubilizing and insecticidal effects of microemulsion pesticides are not only related to the properties of the pesticide itself, but also to the properties and composition of the oil phase, emulsifier, and co-emulsifier used to prepare the microemulsion.

[0009] There are no existing reports on the preparation of juglone into microemulsions for use in pesticides. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, the technical problem solved by the present invention is to provide a novel green juglone microemulsion that is highly efficient, low in toxicity, low in residue, and environmentally friendly, using plant-derived juglone as the insecticidal active ingredient and supplemented with environmentally friendly additives. This emulsion avoids the use of harmful organic solvents that are widely used in traditional chemical pesticide formulations and has stronger insecticidal activity.

[0011] This invention is implemented according to the following technical solution:

[0012] This invention provides a juglone microemulsion, which comprises juglone, an oil phase, an emulsifier, a co-emulsifier, and water, with the following mass percentage composition: juglone: ​​2.5-10%, oil phase: 5-25%, emulsifier: 5-15%, co-emulsifier: 5-35%, and the balance being water.

[0013] Preferably, the mass percentage composition of each component is as follows: juglone: ​​4-6%, oil phase: 8-15%, emulsifier: 8-15%, co-emulsifier: 20-30%, and the balance being water.

[0014] The mass ratio of the emulsifier to the co-emulsifier is 1:0.5-1:3, preferably 1:2-1:3.

[0015] The oil phase is one or a combination of palm oil, castor oil, oleic acid, ethyl oleate, n-hexane, propylene glycol diacetate (PGDA), turpentine, squalane, caprylic / capric glyceride, and isopropyl myristate.

[0016] Furthermore, the oil phase is preferably composed of ethyl oleate, PGDA, a combination of ethyl oleate and PGDA, a combination of isopropyl myristate and n-hexane, glyceryl caprylate, a combination of squalane and PGDA, or a combination of palm oil and PGDA.

[0017] The emulsifier is one or a combination of several of the following: Pluronic F68, Tween-80, polyoxyethylene castor oil EL-40, lauryl alcohol polyoxyethylene 7 ether (AEO-7), lauryl alcohol polyoxyethylene 7 ether phosphate (MOA-7P), octadecanol polyoxyethylene ether phosphate (ODEP-98), polyethylene glycol octylphenyl ether (Trappon X100), isomeric dodecyl alcohol polyoxyethylene ether 9 (E9), and calcium dodecylbenzenesulfonate (agricultural emulsion 500#).

[0018] Furthermore, the emulsifier is preferably a combination of Tween-80, polyoxyethylene castor oil EL-40, AEO-7 and E9, a combination of MOA-7P and Triton X100, agricultural emulsion 500#, a combination of Tween-80 and E9, or a combination of F68 and ODEP-98.

[0019] The emulsifier is one or a combination of several of anhydrous ethanol, glycerin, propylene glycol, and isopropanol.

[0020] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is ethyl oleate, PGDA or a combination of both, the emulsifier is Tween 80 or polyoxyethylene castor oil EL-40, and the co-emulsifier is anhydrous ethanol.

[0021] When the oil phase is a combination of ethyl oleate and PGDA, the mass ratio of ethyl oleate to PGDA is 1-2:1;

[0022] The mass ratio of Tween 80 or polyoxyethylene castor oil EL-40 to anhydrous ethanol is 1:0.5-1:3, preferably 1:2-1:3;

[0023] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is isopropyl myristate, n-hexane or a combination thereof, the emulsifier is AEO-7, E9 or a combination thereof, and the co-emulsifier is glycerol;

[0024] When the oil phase is a combination of isopropyl myristate and n-hexane, the mass ratio of isopropyl myristate to n-hexane is 1:2-3;

[0025] When the emulsifier is a combination of AEO-7 and E9, the mass ratio of AEO-7 to E9 is 1-2:1.

[0026] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is PGDA, the emulsifier is MOA7P, Triton X100 or a combination of both, and the co-emulsifier is anhydrous ethanol;

[0027] When the emulsifier is a combination of MOA7P and Triton X100, the mass ratio of MOA7P to Triton X100 is 1:1-2.

[0028] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is caprylic / capric triglyceride, the emulsifier is E9, agricultural emulsion 500# or a combination of both, and the co-emulsifier is anhydrous ethanol;

[0029] When the emulsifier is a combination of E9 and Agricultural Emulsion 500#, the mass ratio of E9 to Agricultural Emulsion 500# is 1-2:1.

[0030] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is squalane, PGDA or a combination of both, the emulsifier is Tween 80, E9 or a combination of both, and the co-emulsifier is isopropanol;

[0031] When the oil phase is a combination of squalane and PGDA, the mass ratio of squalane to PGDA is 1:2-3;

[0032] When the emulsifier is a combination of Tween 80 and E9, the mass ratio of Tween 80 to E9 is 1-2:1.

[0033] The present invention preferably uses the following juglone microemulsion, wherein the oil phase is palm oil, PGDA or a combination of both, the emulsifier is F68, ODEP-98 or a combination of both, and the co-emulsifier is anhydrous ethanol;

[0034] When the oil phase is a combination of palm oil and PGDA, the mass ratio of palm oil to PGDA is 1-2:1;

[0035] When the emulsifier is a combination of F68 and ODEP-98, the mass ratio of F68 to ODEP-98 is 1:2-3.

[0036] This invention provides a method for preparing the juglone microemulsion, the specific steps of which are as follows:

[0037] 1) Mix the prescribed amounts of emulsifier and co-emulsifier evenly;

[0038] 2) Dissolve juglone in the oil phase to obtain a juglone oil phase solution;

[0039] 3) Slowly add the juglone oil phase solution obtained in step 2) to the solution obtained in step 1) while stirring;

[0040] 4) Under stirring conditions, slowly add purified water to the mixture obtained in step 3) to the prescribed amount to obtain the final product.

[0041] This invention provides the application of the juglone microemulsion in the preparation of pesticides.

[0042] The pesticide mentioned is one that kills cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers.

[0043] This invention provides a method for using the aforementioned juglone microemulsion as a pesticide to kill cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers:

[0044] Dilute the juglone microemulsion (concentration 12.5–200 mg / L) and spray it on plants or crops containing cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers.

[0045] This invention prepares microemulsions by dropwise addition of an aqueous phase to a mixed solution of an oil phase, emulsifier, and co-emulsifier. The critical change points of the system are recorded, a pseudo-ternary phase diagram is plotted, and the effects of each component and its proportion on microemulsion formation are investigated. The area of ​​the microemulsion region in the phase diagram is calculated using ImagePro software. A suitable oil phase is selected based on the size of the microemulsion region, with larger areas being preferred. Suitable Km values, oil phases, and emulsifiers are then screened.

[0046] Based on the Box-Behnken response surface design principle, the amount of oil phase, emulsifier, and water were selected as independent variables, and PDI was used as the response value. The Design-Expert software was used to design the experimental scheme to obtain the optimal formulation combination.

[0047] During the preparation of juglone microemulsions, the juglone microemulsions prepared according to the formulation of this invention all exhibit significant insecticidal activity.

[0048] The beneficial effects of this invention are:

[0049] The juglone microemulsion of the present invention uses plant-derived juglone as the main drug. The prepared juglone microemulsion is an O / W type microemulsion, which is a clear and stable brown liquid. It can be diluted and sprayed directly onto the leaves of crops to kill and repel insects.

[0050] The juglone microemulsion prepared by this invention is an O / W type microemulsion with a particle size between 180 and 310 nm and a PDI of less than 0.5, which greatly increases the solubility of juglone. It can be diluted with water in any proportion, resulting in a clear appearance, high system loading, and good dispersion of juglone. Compared with traditional emulsions, it can significantly reduce the amount of juglone used. The system has low surface tension, excellent leaf spreadability, and good insecticidal and insect repellent effects. Compared with traditional chemical pesticides, the juglone microemulsion of this invention has advantages such as being environmentally friendly, having diverse biological activities, being less likely to induce pesticide resistance in pests, and being relatively safe for non-target organisms. Attached Figure Description

[0051] Figure 1 The selection of the mass ratio of emulsifier to co-emulsifier for Scheme 1.

[0052] Figure 2 The selection of the oil phase type for Scheme 1.

[0053] Figure 3The selection of emulsifier types for Scheme 1.

[0054] Figure 4 This is the PDI response surface diagram for Scheme 1. Detailed Implementation

[0055] Prescription screening:

[0056] Option 1:

[0057] Using juglone as the active ingredient, ethyl oleate and PGDA as the oil phase, polyoxyethylene castor oil EL-40 as the emulsifier, anhydrous ethanol as the co-emulsifier, and purified water as the emulsion formulation, the Km, oil phase type, and emulsifier type were screened according to the following method.

[0058] The prescription screening process is as follows:

[0059] (1) Selection of Km value (mass ratio of emulsifier to co-emulsifier)

[0060] Weigh appropriate amounts of polyoxyethylene castor oil EL-40 and anhydrous ethanol at Km ratios of 1:1, 1:2, 2:1, and 1:3, respectively, and mix thoroughly at 30°C to form a mixed emulsifier. Then, mix this emulsion with a mixture of ethyl oleate and PGDA (1:1 volume ratio). While stirring, slowly add purified water dropwise, observing the critical point of the system and recording the amount of water added. If the system remains clear during water addition, stop adding water when the required amount is reached. Use Origin software to plot a pseudo-ternary phase diagram, and use ImagePro software to calculate the area of ​​the microemulsion region in the phase diagram. The largest microemulsion region is considered the optimal Km value. The results are shown below. Figure 1 .

[0061] The results showed that when Km was 1:0.5-1:3, the area of ​​the microemulsion region was greater than 2.5, and when Km was 1:2-1:3, the area of ​​the microemulsion region was greater than 3. Therefore, the preferred mass ratio of polyoxyethylene castor oil EL-40 to anhydrous ethanol was 1:2-1:3.

[0062] (2) Selection of oil phase

[0063] Polyoxyethylene castor oil EL-40 and anhydrous ethanol were mixed at a mass ratio of 1:2 and stirred at 30°C to form a mixed emulsion. This emulsion was then mixed thoroughly with ethyl oleate and (ethyl oleate / PGDA = 1:1). Purified water was slowly added dropwise while stirring, and the critical point of the system was observed and the amount of water used was recorded. A pseudo-ternary phase diagram was plotted, and the oil phase with the largest microemulsion area was considered the best. Results are shown below. Figure 2 .

[0064] The results showed that when ethyl oleate and (ethyl oleate / PGDA = 1:1) were used as the oil phase, the area of ​​the microemulsion region was greater than 2.5, while when ethyl oleate / PGDA = 1:1 was used as the oil phase, the area of ​​the microemulsion region was greater than 3. Therefore, the ethyl oleate / PGDA = 1:1 mixed oil is preferred as the oil phase.

[0065] (3) Selection of emulsifier

[0066] Tween-80 and polyoxyethylene castor oil EL-40 were each mixed with anhydrous ethanol at a mass ratio of 1:2, and magnetically stirred at 30°C to form a mixed emulsion. This mixture was then thoroughly mixed with ethyl oleate, and purified water was slowly added dropwise while stirring. The system was observed to reach its critical point, and the amount of water used was recorded. A pseudo-ternary phase diagram was plotted, and the area of ​​the microemulsion region in the phase diagram was calculated. The region with the larger area was considered the suitable emulsifier. Results are shown below. Figure 3 .

[0067] The results showed that when Tween-80 or polyoxyethylene castor oil EL-40 was used as the emulsifier, the area of ​​the microemulsion region was greater than 2, while when polyoxyethylene castor oil EL-40 was used as the emulsifier, the area of ​​the microemulsion region was close to 3. Therefore, polyoxyethylene castor oil EL-40 is preferred as the emulsifier.

[0068] (4) Response surface methodology optimization experiment

[0069] Through single-factor experiments, the initial screening of the juglone microemulsion formulation was conducted, using a 1:1 mixture of ethyl oleate and PGDA as the oil phase, polyoxyethylene castor oil EL-40 as the emulsifier, anhydrous ethanol as the co-emulsifier, and purified water; the Km ratio was 1:2. Based on the Box-Behnken design principle, the oil phase dosage (A), mixed emulsifier dosage (B), and aqueous phase dosage (C) were selected as independent variables, with the polymeric dispersion index (PDI) as the response value. The experimental design was conducted using Design-Expert software. The factor levels are shown in Table 1, and the experimental arrangement and results are shown in Table 2.

[0070] Table 1. Factor levels in the Box-Behnken trial for prescription optimization.

[0071]

[0072] Table 2. Prescription Optimization: Box-Behnken Trial Design and Results

[0073]

[0074] The Design-Expert software was used to perform regression fitting on the various factors of the juglone microemulsion formulation in the Box-Behnken design. The binomial regression equation is as follows:

[0075] Y=0.3208+0.0249A-0.0734B+0.131C-0.0208AB-0.0715AC+0.0205BC+0.1765A 2 +0.0885B 2 +0.076C 2 Model R 2 The value is 0.9103. See the response surface plot. Figure 4 .

[0076] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0077] Option 2:

[0078] Using juglone as the active ingredient, isopropyl myristate and n-hexane as the oil phase, AEO-7 and E-9 as emulsifiers, and glycerol as a co-emulsifier, a preliminary microemulsion formulation was formed with purified water. Km, oil phase type, and emulsifier type were screened according to the method in Scheme 1.

[0079] The results showed that the mixed oil phase composed of isopropyl myristate and n-hexane at a mass ratio of 1:2 was better than using isopropyl myristate or n-hexane alone, and also better than the mixed oil phase composed of oleic acid and n-hexane at a mass ratio of 1:2. There was no significant difference when the mass ratio of isopropyl myristate to n-hexane was 1:2-3. The mixed emulsifier composed of AEO-7 and E-9 at a mass ratio of 1-2:1 was better than AEO-7 or E-9 alone as an emulsifier, with a mass ratio of 5:3 showing the best effect. Km ratios of 1:2-3 all showed good results, but Km1:2 was more effective than Km1:3.

[0080] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0081] Option 3:

[0082] Juglone as the active ingredient, PGDA as the oil phase, MOA7P and Triton X100 as emulsifiers, anhydrous ethanol as a co-emulsifier, and purified water were used to form a preliminary microemulsion formulation. Km, oil phase type, and emulsifier type were screened according to the method in Scheme 1.

[0083] The results showed that PGDA was better than glyceryl caprylate as an oil phase emulsifier; the mixed emulsifier of MOA7P and Triton X100 at a mass ratio of 1:1-2 was better than MOA7P or Triton X100 alone as an emulsifier, and the effect was better at a ratio of 1:1; anhydrous ethanol was better than 1,2-propanediol as a co-emulsifier; the Km1:2-3 ratios were all good, but Km1:2 was better than Km1:3.

[0084] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0085] Option 4:

[0086] Using juglone as the active ingredient, caprylic / capric triglyceride as the oil phase, E9 and concentrated emulsion 500# as emulsifiers, anhydrous ethanol as a co-emulsifier, and purified water as a preliminary microemulsion formulation, Km, oil phase type, and emulsifier type were screened according to the method in Scheme 1.

[0087] The results showed that caprylic / capric triglyceride was more effective as an oil phase than squalane or castor oil; the mixed emulsifier composed of E9 and concentrated emulsion 500# at a mass ratio of 1-2:1 was more effective than E9 or concentrated emulsion 500# alone as an emulsifier, and the effect was better at a ratio of 1:1; anhydrous ethanol was more effective as a co-emulsifier than isopropanol; the Km1:2-3 ratios were all effective, but the Km1:3 ratio was more effective than the Km1:2 ratio.

[0088] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0089] Option 5:

[0090] Juglone as the active ingredient, squalane and PGDA as the oil phase, Tween-80 and E-9 as emulsifiers, isopropanol as a co-emulsifier, and purified water to form a preliminary microemulsion formulation. Km, oil phase type, and emulsifier type were screened according to the method in Scheme 1.

[0091] The results showed that the mixed oil phase composed of squalane and PGDA at a mass ratio of 1:2-3 was better than using squalane or PGDA alone, and the effect was even better when the mass ratio was 1:2; the mixed emulsifier composed of Tween-80 and E-9 at a mass ratio of 1-2:1 was better than the effect of Tween-80 or E-9 alone as an emulsifier, and the effect was even better when the mass ratio was 3:2; the Km1:2-3 ratio was good, but the Km1:2 ratio was better than the Km1:3 ratio; and isopropanol was better than anhydrous ethanol or 1,2-propanediol as a co-emulsifier.

[0092] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0093] Option 6:

[0094] Using juglone as the active ingredient, palm oil and PGDA as the oil phase, F68 and ODEP-98 as emulsifiers, anhydrous ethanol as a co-emulsifier, and purified water as a preliminary microemulsion formulation, Km, oil phase type, and emulsifier type were screened according to the method in Scheme 1.

[0095] The results showed that the mixed oil phase composed of palm oil and PGDA at a mass ratio of 1-2:1 was better than using palm oil or PGDA alone, and also better than the mixed oil phase composed of turpentine oil and PGDA at a mass ratio of 1-2:1, with the effect being even better at 1:1; the mixed emulsifier composed of F68 and ODEP-98 at a mass ratio of 1:2-3 was better than F68 or ODEP-98 alone as an emulsifier, with the effect being even better at 1:2; the effects of Km1:2-3 were all good, but Km1:2 was better than Km1:3; anhydrous ethanol was better than isopropanol as a co-emulsifier.

[0096] The formulation for preparing the microemulsion was determined based on the regression equation and response surface plot.

[0097] Example 1

[0098] For example, to prepare 100g:

[0099]

[0100] Process: Anhydrous ethanol and polyoxyethylene castor oil EL-40 were mixed evenly at 30℃ to obtain solution A; juglone was dispersed in a mixture of ethyl oleate and PGDA and stirred evenly to obtain solution B; solution B was added dropwise to solution A at a rate of 1 g / min at 30℃ and 150 r / min, and stirred continuously for 5 minutes to obtain solution C; distilled water was added dropwise to solution C at a rate of 1 g / min at 30℃ with continuous stirring for 10 minutes to obtain the final product. After diluting the sample 100 times, the average particle size was measured to be 256 nm, and the average PDI value was 0.364.

[0101] Example 2

[0102] For example, to prepare 100g:

[0103] prescription:

[0104]

[0105]

[0106] Process: AEO-7, E9, and glycerol were mixed evenly at 30°C to obtain solution A; juglone was dissolved in n-hexane / isopropyl myristate and stirred evenly to obtain solution B; solution B was added dropwise to solution A at a rate of 1 g / min at 30°C and 150 r / min, and stirred continuously for 5 minutes to obtain solution C; distilled water was added dropwise to solution C at a rate of 1 g / min at 30°C with continuous stirring for 10 minutes to obtain the final product. The sample was diluted 100 times and the average particle size was measured to be 272 nm, with a mean PDI value of 0.317.

[0107] Example 3

[0108] For example, to prepare 100g:

[0109] prescription:

[0110]

[0111] Process: MOA7P, Triton X100, and anhydrous ethanol were mixed evenly at 30°C to obtain solution A; juglone was dissolved in PGDA and stirred evenly to obtain solution B; solution B was added dropwise to solution A at a rate of 1 g / min at 150 r / min under 30°C and stirring for 5 minutes to obtain solution C; distilled water was added dropwise to solution C under continuous stirring at 1 g / min under 30°C and stirring for 10 minutes to obtain the final product. After diluting the sample 100 times, the average particle size was measured to be 189 nm, and the average PDI value was 0.341.

[0112] Example 4

[0113] For example, to prepare 100g:

[0114] prescription:

[0115]

[0116] Process: E9, concentrated milk (500#), and anhydrous ethanol were mixed evenly at 30°C to obtain solution A; juglone was dispersed in caprylic / capric triglyceride and stirred evenly to obtain solution B; solution B was added dropwise to solution A at a rate of 1 g / min at 30°C and 150 r / min, with continuous stirring for 5 minutes to obtain solution C; distilled water was added dropwise to continuously stirred solution C at a rate of 1 g / min at 30°C, with continuous stirring for 10 minutes to obtain the final product. After diluting the sample 100 times, the average particle size was measured to be 215 nm, and the average PDI value was 0.389.

[0117] Example 5

[0118] For example, to prepare 100g:

[0119] prescription:

[0120]

[0121] Process: E9, Tween-80, and isopropanol were mixed evenly at 30°C to obtain solution A; Juglone was dispersed in a mixture of squalane and PGDA and stirred evenly to obtain solution B; B was added dropwise to solution A at a rate of 1 g / min at 150 r / min under 30°C and stirring for 5 minutes to obtain solution C; Distilled water was added dropwise to C under continuous stirring at a rate of 1 g / min at 30°C and stirring for 10 minutes to obtain the final product. After the sample was diluted 100 times, the average particle size was measured to be 308 nm, and the average PDI value was 0.407.

[0122] Example 6

[0123] For example, to prepare 100g:

[0124] prescription:

[0125]

[0126] Process: F68, ODEP-98, and anhydrous ethanol were mixed evenly at 30°C to obtain solution A; juglone was dispersed in a mixture of palm oil and PGDA and stirred evenly to obtain solution B; solution B was added dropwise to solution A at a rate of 1 g / min at 30°C and 150 r / min, and stirred continuously for 5 minutes to obtain solution C; distilled water was added dropwise to solution C at a rate of 1 g / min at 30°C with continuous stirring for 10 minutes to obtain the final product. The sample was diluted 100 times and the average particle size was measured to be 226 nm, with a mean PDI value of 0.483.

[0127] Example 7: Evaluation of insecticidal activity of juglone microemulsion

[0128] For microemulsions with the same concentration of active ingredient, larger particle sizes result in smaller spreading areas after application and poorer efficacy. Example 5 is the microemulsion with the largest average particle size among the above examples, and it also has the smallest spreading area. Selecting Example 5 for insecticidal activity evaluation can provide valuable insights for differentiating other examples.

[0129] 1. Methods: The stomach poison toxicity of juglone microemulsion to cabbage caterpillar, tea geometrid moth larva, and false-eyed green leafhopper was tested using the poison bait method.

[0130] 2. Experimental Materials and Equipment

[0131] (1) Experimental materials:

[0132] Test reagent: 5% juglone microemulsion prepared according to the formulation and process of Example 5.

[0133] Test insects: cabbage caterpillars, tea geometrid moth larvae, and false-eyed green leafhoppers raised indoors without pesticide exposure.

[0134] (2) Experimental equipment: petri dishes, filter paper, distilled water, cabbage leaves, tea leaves, etc.

[0135] 3. Experimental Procedure

[0136] (1) Dilute the juglone microemulsion with distilled water at 250, 500, 1000, 2000 and 4000 times respectively for later use. The samples obtained according to the dilution ratio from high to low are labeled as sample 1-5 respectively, and the control is distilled water;

[0137] (2) Place filter paper at the bottom of the petri dish, add a small amount of distilled water to wet it evenly, and mark it.

[0138] (3) Inoculate 20 test insects into each culture dish, and repeat each treatment or control 3 times.

[0139] (4) After soaking the leaf disc in the drug solution or distilled water for 5-10 seconds, take it out, air dry it, and place it in a petri dish with the corresponding concentration marking.

[0140] (5) After 24 hours, observe the experimental results, calculate the mortality rate and corrected mortality rate (both are the average of 3 replicates), and calculate the toxicity regression equation and LC. 50 value.

[0141] 4. Results and Calculations

[0142] The survival and mortality of the insects were checked 24 hours later. The data are shown in Table 3. The toxicity regression equation was calculated and is shown in Table 4.

[0143] Table 3. Microemulsion concentration and insect mortality rate

[0144]

[0145]

[0146] The results showed that when the concentration of juglone in the microemulsion was 12.5-200 mg / L, the juglone microemulsion had varying degrees of killing effect on cabbage caterpillars, tea geometrid moth larvae, and false-eyed green leafhoppers. The mortality rate of cabbage caterpillars reached 30-95%, that of tea geometrid moth larvae reached 40-95%, and that of false-eyed green leafhoppers reached 65-100%. The higher the concentration, the higher the mortality rate and the better the killing effect. When the concentration was 100-200 mg / L, the mortality rate of cabbage caterpillars and tea geometrid moth larvae reached over 90%. When the concentration was 50-200 mg / L, the mortality rate of false-eyed green leafhoppers reached over 90%, essentially achieving complete eradication.

[0147] Table 4. Regression equations for the toxicity of juglone microemulsions to different insects.

[0148]

[0149] In this invention, due to variations in microemulsion particle size, the area spread after application at the same concentration differs, thus affecting the overall effect. This invention uses microemulsions with the largest particle size for insecticidal activity testing, and the results show that they exhibit good insecticidal activity. Furthermore, the microemulsions of Examples 1-4 and 6 of this invention, with even smaller particle sizes, should also demonstrate significant insecticidal activity, with their insecticidal activity being superior to that of Example 5.

[0150] Example 8: LC-100 of juglone microemulsions from Examples 1-6 against different insects 50 Value and 90% confidence interval

[0151] Table 5. LC50 of juglone microemulsions from Example 1 against different insects. 50 Value and 90% confidence interval

[0152]

[0153]

[0154] Table 6. LC-100 of juglone microemulsions from Example 2 against different insects. 50 Value and 90% confidence interval

[0155]

[0156] Table 7. LC50 of juglone microemulsions from Example 3 against different insects. 50 Value and 90% confidence interval

[0157]

[0158] Table 8. LC50 of juglone microemulsions from Example 4 against different insects. 50 Value and 90% confidence interval

[0159]

[0160] Table 9. LC50 of juglone microemulsions from Example 5 against different insects. 50 Value and 90% confidence interval

[0161]

[0162] Table 10. LC-10 of Juglone Microemulsions from Example 6 against Different Insects 50 Value and 90% confidence interval

[0163]

[0164] The results showed that the juglone microemulsion of the present invention had varying degrees of killing effect on cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers, and the killing effect on false-eyed green leafhoppers was the strongest.

Claims

1. A juglone microemulsion, characterized in that: The juglone microemulsion comprises juglone, an oil phase, an emulsifier, a co-emulsifier, and water, with the following mass percentage composition: juglone: ​​2.5–10%, oil phase: 5–25%, emulsifier: 5–15%, co-emulsifier: 5–35%, and the balance being water. Preferably, the composition is: juglone: ​​4–6%, oil phase: 8–15%, emulsifier: 8–15%, co-emulsifier: 20–30%, and the balance being water.

2. The juglone microemulsion according to claim 1, characterized in that: The oil phase is one or a combination of palm oil, castor oil, oleic acid, ethyl oleate, n-hexane, propylene glycol diacetate, turpentine, squalane, glyceryl caprylate, and isopropyl myristate; the emulsifier is one or a combination of poloxamer 188, Tween-80, polyoxyethylene castor oil EL-40, lauryl alcohol polyoxyethylene 7 ether, lauryl alcohol polyoxyethylene 7 ether phosphate, caprylate alcohol polyoxyethylene ether phosphate, polyethylene glycol octylphenyl ether, isomeric dodecyl alcohol oxyethylene ether 9, and calcium dodecylbenzene sulfonate; the co-emulsifier is one or a combination of anhydrous ethanol, glycerin, 1,2-propanediol, and isopropanol.

3. The juglone microemulsion according to claim 1 or 2, characterized in that, The mass ratio of the emulsifier to the co-emulsifier is 1:0.5-1:3, preferably 1:2-1:

3.

4. The juglone microemulsion according to claim 1 or 2, characterized in that, The oil phase is ethyl oleate, propylene glycol diacetate, or a combination thereof; isopropyl myristate, n-hexane, or a combination thereof; propylene glycol diacetate; glyceryl caprylate; squalane, propylene glycol diacetate, or a combination thereof; palm oil, propylene glycol diacetate, or a combination thereof; the emulsifier is: polyoxyethylene castor oil EL-40; lauryl alcohol polyoxyethylene 7 ether; isododecyl alcohol oxyethylene ether 9, or a combination thereof; lauryl alcohol polyoxyethylene 7 ether phosphate; polyethylene glycol octylphenyl ether, or a combination thereof; isododecyl alcohol oxyethylene ether 9; calcium dodecylbenzene sulfonate, or a combination thereof; the emulsifier is Tween 80; isododecyl alcohol oxyethylene ether 9, or a combination thereof; poloxamer 188; octyldecyl alcohol polyoxyethylene ether phosphate, or a combination thereof; the co-emulsifier is anhydrous ethanol, glycerin, and isopropanol.

5. The juglone microemulsion according to any one of claims 1-4, characterized in that: In the juglone microemulsion, The oil phase is ethyl oleate, PGDA or a combination of both, the emulsifier is Tween 80 or polyoxyethylene castor oil EL-40, and the co-emulsifier is anhydrous ethanol. Alternatively, the oil phase may be isopropyl myristate, n-hexane, or a combination thereof, the emulsifier may be AEO-7, E9, or a combination thereof, and the co-emulsifier may be glycerol; Alternatively, the oil phase may be PGDA, the emulsifier may be MOA7P, Triton X100 or a combination of both, and the co-emulsifier may be anhydrous ethanol; Alternatively, the oil phase may be glyceryl caprylate, the emulsifier may be E9, agricultural emulsion 500# or a combination of both, and the co-emulsifier may be anhydrous ethanol; Alternatively, the oil phase may be squalane, PGDA, or a combination thereof, the emulsifier may be Tween 80, E9, or a combination thereof, and the co-emulsifier may be isopropanol; Alternatively, the oil phase may be palm oil, PGDA, or a combination thereof, the emulsifier may be F68, ODEP-98, or a combination thereof, and the co-emulsifier may be anhydrous ethanol.

6. The method for preparing the juglone microemulsion according to claim 1, characterized in that: The specific steps are as follows: 1) Mix the prescribed amounts of emulsifier and co-emulsifier evenly; 2) Dissolve juglone in the oil phase; 3) Slowly add the juglone oil phase solution to the solution obtained in 1) while stirring; 4) Slowly add purified water to the mixture obtained in 3) under stirring to the prescribed amount, and you will get the product.

7. The use of the juglone microemulsion according to any one of claims 1-5 in the preparation of pesticides.

8. The use of the juglone microemulsion according to any one of claims 1-5 in the preparation of insecticides.

9. The application according to claim 7, characterized in that, The pesticide mentioned is one that kills cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers.

10. The application according to any one of claims 7-9, characterized in that, The juglone microemulsion was diluted and sprayed onto plants or crops containing cabbage caterpillars, tea geometrid moth larvae, or false-eyed green leafhoppers; the concentration of the diluted juglone microemulsion was 12.5–200 mg / L.

Images