Preparation method of mustard oil-containing Pickering emulsion gel and application of mustard oil-containing Pickering emulsion gel in prevention and control of cruciferous pest plutella xylostella

Abstract

The invention provides application of mustard oil in preparation of a pesticide for preventing and treating cruciferous pest plutella xylostella. The invention further provides the Pickering emulsion gel containing the mustard oil, and the invention further provides the Pickering emulsion gel containing the mustard oil. According to the preparation method of the green pesticide mustard oil Pickering emulsion gel provided by the invention, the mustard oil is entrapped in the nano-carrier to form the stable Pickering emulsion gel. The compound is simple in preparation process, green and environment-friendly, high in safety and stability and relatively high in killing power to pests, has antibacterial activity as a green pesticide, is green and efficient, is easily degraded by the environment, can remarkably improve the pesticide efficiency and reduce the environmental influence, and solves the problems of high toxicity, difficulty in degradation and low utilization rate of the existing pesticide.

Description

Technical Field

[0001] The present invention relates to the use of mustard oil in the preparation of pesticides for controlling the diamondback moth, a cruciferous pest, and a Pickering emulsion gel containing mustard oil, its preparation method and uses. Background Art

[0002] In traditional agricultural practices, chemically synthesized pesticides are widely used. However, the long-term use of chemical pesticides has led to an increase in pest resistance and has negative impacts on non-target organisms (such as beneficial insects and beneficial microorganisms), disrupting the ecological balance and reducing biodiversity. In recent years, the rapid rise of nanotechnology has provided new strategies and technical means for the development of pesticides towards high efficiency, low toxicity, and low residue. Green nano-pesticides are a new type of pesticide system formed by encapsulating or dispersing active ingredients of natural or biological origin in nano-carriers using nanotechnology, which have the characteristics of high efficiency, low toxicity, low residue, and environmental friendliness. Compared with traditional pesticide formulations, nano-pesticide formulations are beneficial to improving the delivery efficiency of the active ingredients of pesticides, enhancing the biological activity and utilization rate of the active ingredients, and the specificity for target pests. Such nano-formulations can act more precisely on target pests, reducing the impact on the environment and non-target organisms. In addition, green nano-pesticides usually use degradable nano-materials, reducing the risk of residue and accumulation in the environment, meeting the development needs of sustainable agriculture. Green nano-pesticides not only improve the efficacy and safety of pesticides but also provide innovative solutions for the greening and precision of agricultural production.

[0003] A Pickering emulsion gel is a semi-solid or gel-like material stabilized by solid particles, and its formation depends on the adsorption of solid particles at the oil-water interface and the three-dimensional network structure formed by physical or chemical interactions between droplets or particles. Compared with Pickering emulsions, Pickering emulsion gels have higher mechanical strength and viscoelasticity, can maintain their shape and are not prone to flow, which shows significant advantages in the field of functional materials. Its advantages are that it not only inherits the high stability, low toxicity, and environmental friendliness of Pickering emulsions but also endows the material with stronger structural controllability and multi-functionality through the gelation process. For example, in the pesticide field, it can encapsulate pesticides to achieve slow release and long-term effects of pesticides; in the food industry, it can be used to improve texture, in the pharmaceutical field, it can achieve slow release and targeted delivery of drugs, and in materials science, it can be used as the matrix of high-performance porous materials or composite materials. Generally speaking, Pickering emulsion gels can be regarded as a special form of Pickering emulsions, and Pickering emulsion gels are superior to traditional Pickering emulsions in terms of stability, functionality, and application scope. It realizes the transformation from liquid to gel state through additional interactions, thus possessing higher functionality and application potential.

[0004] Mustard essential oil is a volatile liquid extracted from the seeds of mustard plants, rich in allyl isothiocyanate, which not only has bactericidal and antibacterial effects but also can repel and kill insects. Currently, there is no report on using mustard essential oil to control the cruciferous pest Plutella xylostella. Moreover, mustard essential oil has high volatility and is easily decomposed under light and high temperature. There is no reported method to solve the volatility and stability of mustard essential oil. Summary of the Invention

[0005] The present invention provides the use of mustard oil in the preparation of pesticides for controlling the cruciferous pest Plutella xylostella, as well as a Pickering emulsion gel containing mustard oil, its preparation method and use.

[0006] Use of mustard oil in the preparation of pesticides for controlling the cruciferous pest Plutella xylostella.

[0007] The present invention provides a Pickering emulsion gel containing mustard oil, which is prepared from the following raw materials by volume ratio:

[0008] 3 - 7 parts of zein - tannic acid nano - sodium alginate composite particles, 3 - 6 parts of soybean oil, 1 - 3 parts of mustard oil;

[0009] In the zein - tannic acid nano - sodium alginate composite particles, the concentration of zein is 0.5 - 4%, and the concentration of sodium alginate is 0.1 - 2%;

[0010] The zein - tannic acid nano - sodium alginate composite particles are prepared from the following raw materials by weight ratio: 1 - 6 parts of zein, 1 - 2 parts of tannic acid, 1 - 3 parts of sodium alginate.

[0011] Preferably, it is prepared from the following raw materials by volume ratio:

[0012] 5 parts of zein - tannic acid nano - sodium alginate composite particles, 4 parts of soybean oil, 1 part of mustard oil;

[0013] In the zein - tannic acid nano - sodium alginate composite particles, the concentration of zein is 2%, and the concentration of sodium alginate is 1%;

[0014] The zein - tannic acid nano - sodium alginate composite particles are prepared from the following raw materials by weight ratio: 4 parts of zein, 1.2 parts of tannic acid, 2 parts of sodium alginate.

[0015] Among them, the zein - tannic acid nano - sodium alginate composite particles are prepared by the anti - solvent precipitation method and the method of mixed magnetic stirring.

[0016] Among them, the preparation method of the zein-tannic acid nano-sodium alginate composite particles is as follows:

[0017] a. Weigh the raw materials in each weight ratio;

[0018] b. Dissolve zein in an ethanol solution, and then add tannic acid. After dissolution, a zein / tannic acid ethanol solution is obtained;

[0019] c. Inject the fully dissolved zein / tannic acid ethanol solution into water, and stir magnetically and heat to remove the alcohol to obtain zein / tannic acid nanoparticles;

[0020] d. Add sodium alginate to the zein / tannic acid nanoparticles and stir for 3 - 6 h to obtain zein-tannic acid nano-sodium alginate composite particles.

[0021] Among them, the alcohol solution in step b is a 65 - 80% ethanol aqueous solution; the mass-to-volume ratio of zein to the alcohol solution is 5 - 40 g:1 L;

[0022] The stirring conditions in step c are: rotation speed 600 - 800 r / min, temperature 40 - 60 °C, and stirring time 2 - 4 h;

[0023] The addition ratio of sodium alginate in d is 1%, rotation speed 600 - 800 r / min, temperature 20 - 30 °C, and stirring time 3 - 6 h.

[0024] The present invention also provides a preparation method of the Pickering emulsion gel containing mustard oil as described above, which includes the following steps:

[0025] Mix the zein-tannic acid nano-sodium alginate composite particles and the oil phase evenly, and shear at a speed of 10000 - 25000 r / min for 1 - 5 min to obtain a Pickering emulsion gel.

[0026] The present invention also provides the use of the Pickering emulsion gel containing mustard oil as described above in the preparation of a pesticide for controlling the cruciferous pest Plutella xylostella.

[0027] The present invention provides a preparation method of a green pesticide mustard oil Pickering emulsion gel. This method encapsulates mustard oil in a nano-carrier to form a stable Pickering emulsion gel. Its preparation process is simple, green and environmentally friendly, with high safety and stability. It has high lethality to pests, and as a green pesticide, it has antibacterial activity. It is green, efficient and easily degraded by the environment, can significantly improve the pesticide efficiency and reduce the environmental impact, and solves the problems of high toxicity, difficult degradation and low utilization rate of existing pesticides.

[0028] The green pesticide, mustard oil Pickering emulsion gel, combines the natural insecticidal properties of mustard oil with the efficient carrier function of Pickering emulsion gel, making it a novel green nano-pesticide. As a natural plant extract, mustard oil has broad-spectrum insecticidal, bactericidal, and insect repellent effects, while having less impact on non-target organisms and the environment, meeting the requirements of low toxicity and low residue for green pesticides. The three-dimensional network structure of Pickering emulsion gel can precisely encapsulate mustard oil, protecting its active ingredients from environmental degradation such as photolysis and oxidation, extending its action time and improving its utilization rate. In addition, the slow-release characteristics of the emulsion gel can achieve the slow release of mustard oil, reduce the application frequency, and lower the pesticide dosage and cost. At the same time, the preparation of Pickering emulsion gel usually does not require the additional addition of chemical surfactants, further reducing the potential hazards to the environment and human health. This system can also achieve intelligent release by regulating the degradation rate of the gel or responding to external stimuli (such as pH, temperature, etc.), meeting the needs of precision agriculture, reducing its impact on the environment and non-target organisms, and providing an efficient and environmentally friendly pesticide solution for green agriculture, with broad application prospects. Description of the Drawings

[0029] Figure 1 . Screening of the dosage ratio of zein to tannic acid ((A) Appearance and particle size of ZT NPs on the 1st day; (B) Appearance and inversion pictures of ZT NPs on the 30th day);

[0030] Figure 2 . (A) Appearance and optical microscopy observation of MO PKE(-SA) and MO PKEG(+SA) formulations; (B) Particle size comparison of MO PKE(-SA) and MO PKEG(+SA) on the 1st day and the 30th day;

[0031] Figure 3 . Confocal laser scanning microscopy observation of MO PKE(-SA) and MO PKEG(+SA). The oil phase stained with Nile red appears green under the microscope, and the solid particle stabilizer (aqueous phase) stained with Nile blue appears red under the microscope;

[0032] Figure 4 . Cross-sectional images of MO PKE(-SA) and MO PKEG(+SA) by cryo-scanning electron microscopy;

[0033] Figure 5 . Adhesion of MO PKE(-SA) and MO PKEG(+SA) on cabbage leaves and radish leaves at 0 h, 1 h, and 2 h;

[0034] Figure 6.SO PKEG-Control, MO PKEG-SO PKEG, and the attracting effect of MO PKEG-Control on Plutella xylostella larvae in terms of spatial position. (A) Pictures of the insect-attracting situation of different groups at 1h, 4h, 24h, and 48h; (B) Histogram of the analysis of the number of attracted insects in each group in terms of spatial position;

[0035] Figure 7 . (A) Appearance of the Control, SO PKEG, and MO PKEG groups at different time points; (B) Survival rate of Plutella xylostella larvae in each group; (C) Trajectory diagram of the leaf feeding area in each group; (D) Statistical chart of the leaf feeding area in each group. Detailed implementation method

[0036] Example 1 Preparation of mustard oil Pickering emulsion gel (MO PKEG) of the present invention

[0037] Accurately weigh 4 g of zein and dissolve it in 100 mL of 70% ethanol / water solution. Then add 1.2 g of tannic acid. After complete dissolution, quickly inject 10 mL of the above zein / tannic acid alcohol solution into 20 mL of deionized water. Stir magnetically and heat at 700 r / min and 50 °C for 4 h to volatilize ethanol. Finally, measure the volume and make up to 20 mL with deionized water to obtain a zein / tannic acid nanoparticle suspension with a zein concentration of 2%. Weigh 0.2 g of sodium alginate and add it to 20 mL of 2% zein / tannic acid nanoparticle suspension and stir at a rotation speed of 700 r / min, a temperature of 25 °C, and a stirring time of 4 h to obtain zein-tannic acid nano-sodium alginate composite particles. Take 5 mL of zein-tannic acid nano-sodium alginate composite particles and add them to a 50 mL centrifuge tube. Slowly add 5 mL of the oil phase (4 mL of soybean oil, 1 mL of mustard oil), and shear at a high speed of 20000 r / min for 2 min to obtain mustard oil Pickering emulsion gel (MO PKEG).

[0038] The mustard oil can be commercially available and is purchased from Jiangxi Xuesong Natural Medicinal Oil Co., Ltd. It is inspected according to the GB29980-2013 standard, and all indicators meet the requirements.

[0039] Comparative Example 1 Preparation of mustard oil Pickering emulsion (MO PKE) without sodium alginate

[0040] Accurately weigh 4 g of zein and dissolve it in 100 mL of 70% ethanol / water solution. Then add 1.2 g of tannic acid. After complete dissolution, quickly pour 10 mL of the above zein / tannic acid alcohol solution into 20 mL of deionized water, and magnetically heat and stir at 700 r / min and 50 °C for 4 h to remove ethanol. Finally, measure the volume and make up to 20 mL with deionized water to prepare a zein / tannic acid nanoparticle suspension with a zein concentration of 2%.

[0041] Take 5 mL of the prepared 2% nanoparticle suspension and add it to a 50 mL centrifuge tube. Slowly add 5 mL of the oil phase (4 mL of soybean oil, 1 mL of mustard oil), and shear at high speed at 20000 r / min for 2 min to prepare a mustard oil Pickering emulsion (MO PKE).

[0042] Preparation of Pickering emulsion gel without mustard oil (SO PKEG) in Comparative Example 2

[0043] Accurately weigh 4 g of zein and dissolve it in 100 mL of 70% ethanol / water solution. Then add 1.2 g of tannic acid. After complete dissolution, quickly inject 10 mL of the above zein / tannic acid alcohol solution into 20 mL of deionized water, and magnetically heat and stir at 700 r / min and 50 °C for 4 h to remove ethanol. Finally, measure the volume and make up to 20 mL with deionized water to prepare a zein / tannic acid nanoparticle suspension with a zein concentration of 2%. Weigh 0.2 g of sodium alginate, add it to 20 mL of 2% zein / tannic acid nanoparticle suspension and stir at 700 r / min, 25 °C for 4 h to obtain zein-tannic acid nano-sodium alginate composite particles. Take 5 mL and add it to a 50 mL centrifuge tube. Slowly add 5 mL of the oil phase (soybean oil), and shear at high speed at 20000 r / min for 2 min to prepare a soybean oil Pickering emulsion gel (SOPKEG).

[0044] Example 2 Screening of raw materials in the mustard oil Pickering emulsion gel (MO PKEG) of the present invention

[0045] As Figure 1 shown, when the mass ratio of zein to tannic acid (TA) is from 1:0 to 1:1, on the first day, the nanoparticles of each ratio show a uniform appearance and particle size distribution. Among them, obvious opalescence can be observed for the nanoparticles with the ratios of 1:0, 1:0.25 and 1:0.5 ( Figure 1A). As the storage time extended, on the 30th day, zein nanoparticles with a mass ratio of 1:0 were unstable and aggregated. When the mass ratio of zein to tannic acid reached 1:1, obvious precipitation also occurred, indicating that excessive TA led to the aggregation and composite precipitation of ZT NPs. ZT NPs prepared with the mass ratio of zein to TA between 1:0.25 and 1:0.5 were relatively stable and did not aggregate or precipitate. Figure 1 B). In summary, the ratio of zein:TA between 1:0.25 and 1:0.5 was initially screened as the optimal range. Further research found that excessive TA content (zein:TA ≥ 0.5, w / w) might form cracks on the nanoparticle interface, thus weakening its response to deformation; the stable Pickering emulsion gel prepared with Zein:TA = 1:0.3 had greater gel strength and stability than the emulsion gels prepared with lower ratios. Therefore, Zein:TA = 1:0.3 (w / w) was comprehensively screened as the final formulation of ZT NPs.

[0046] The beneficial effects of the present invention are demonstrated by the following effect tests.

[0047] Test Example 1 Comparison between the mustard oil Pickering emulsion gel (MO PKEG) of the present invention and the mustard oil Pickering emulsion (MO PKE) without sodium alginate

[0048] The appearance, microscopy, and particle size of the prepared mustard oil Pickering emulsion gel (MO PKEG) with sodium alginate added and the mustard oil Pickering emulsion (MO PKE) without sodium alginate added were compared as follows Figure 2 As shown, the sizes of the nanoparticles in the emulsion without sodium alginate added were uneven. Under an optical microscope, more unencapsulated oil phases and aggregated nanoparticles could be observed, and water phase precipitation was shown at the bottom in appearance. The nanoparticles in the emulsion with sodium alginate added were evenly distributed and stable, without creaming phenomenon. Figure 2 A). In addition, the changes in the particle sizes of MO PKE and MO PKEG emulsions on the 1st day and the 30th day were compared. On the 1st day, MO PKE showed an uneven bimodal particle size, with an average particle size of 32.12 ± 17.83 μm. On the 30th day, the particle size of MO PKE became further disordered with a multi-peak phenomenon, and the average particle size was 57.07 ± 21.68 μm, which might be related to further creaming of the particles and the destruction of droplets during storage. The particle size distribution curve of MO PKEG showed a uniform single peak on both the 1st day and the 30th day. The droplet particle size on the 1st day was 26.16 ± 2.16 μm, and the droplet particle size on the 30th day was 30.99 ± 3.10 μm. There was no significant change in the particle size of MO PKEG during storage. Figure 2 B).

[0049] The microstructures of mustard oil Pickering emulsions without sodium alginate (MO PKE) and with sodium alginate (MOPKEG) after staining were observed using a laser scanning confocal microscope. Nile red was used to stain the oil phase, and Nile blue was used to stain the composite particle stabilizer. As Figure 3 shown, the images of the solid-stabilized particles after staining appeared red, and the oil phase appeared green. The emulsion type in both preparations was shown to be oil-in-water. It was observed that MOPKEG had a more uniform droplet morphology, which was consistent with the results of optical microscopy observations. The observation of the microtopography further provided evidence for the appearance stability of MOPKEG.

[0050] The cross-sectional morphology structures of mustard oil Pickering emulsions with and without sodium alginate were observed using a cryogenic scanning electron microscope (Cryo-SEM). As Figure 4 shown, the cross-section of MO PKE (-SA) showed an uneven distribution of emulsion particles, with disordered arrangement of nanoparticles, and no stable composite particle interfacial film was formed at the oil phase interface. However, in MO PKEG (+SA), a neatly arranged network connection of nanoparticles and a uniform droplet distribution were visible. The morphological structure of MO PKEG (+SA) was more complete and plump, and a dense particle layer could be seen forming a film for stabilization and encapsulation at the oil phase interface.

[0051] Test Example 2 Leaf Adhesion Test

[0052] Cabbage leaves and radish leaves were selected to compare the adhesion performance of MO PKE and MOPKEG on the surfaces of different plant leaves and the variation law of adhesion over time. Healthy and mature leaves were collected, washed uniformly, and dried to ensure that there were no water droplets on the surface. Equal doses of MO PKE and MOPKEG were added to fixed areas on the leaves. Three observation time points were set: 0 h, 1 h, and 2 h. The leaves were neatly arranged on a white background, and high-definition images were taken to compare the color changes and the flow range of the preparations. The same leaf area was fixed, with 3 leaves of the same part in each group, and the dynamic changes at 0 h, 1 h, and 2 h were tracked. As Figure 5 shown, the adhesion of the leaves in the MOPKEG (+SA) group was significantly higher than that in the MO PKE (-SA) group. It had a good adhesion effect on the surfaces of two typical cruciferous leaves and formed a hemispherical shape within 0 - 2 h, without obvious flow marks.

[0053] Taking the appearance, creaming situation, optical microscopy observation, confocal microscopy, cryogenic scanning electron microscopy, and leaf adhesion observation of the Pickering emulsion as indicators, according to the above screening results, it was determined that the performance of the mustard oil Pickering emulsion with added sodium alginate was the best in all aspects.

[0054] Trial Example 3: Insect-trapping Test for Different Groups of SO PKEG, MO PKEG, and Control

[0055] As Figure 6 shown, in the SO PKEG-Control spatial combination, the diamondback moth showed no obvious tendency towards SO PKEG or the Control group. At the 1st h, 4th h, and 24th h, there was no significant difference in the number of larvae between the two groups. The results indicated that SO PKEG had no attracting effect on diamondback moth larvae, and like the blank leaf Control group, SO PKEG did not interfere with the behavior and feeding of the diamondback moth, and could be used as a blank control preparation for MO PKEG. The results in the MO PKEG-SO PKEG spatial combination showed that MO PKEG had a significant insect-trapping effect compared to SOPKEG, indicating that the insect-trapping effect originated from mustard oil and was not related to soybean oil used as a blank control. Additionally, the MO PKEG-Control spatial combination further demonstrated that MO PKEG had a significant attracting characteristic for diamondback moth larvae compared to the blank leaf (P<0.05).

[0056] Trial Example 4: Survival Rate and Leaf Feeding Area Test of Diamondback Moth for Different Groups of SO PKEG, MO PKEG, and Control

[0057] The single-group method was used to further explore the effect of MO PKEG on the survival rate of diamondback moth. As Figure 6 shown in A - B, the survival of larvae in the Control group, SO PKEG group, and MO PKEG group was recorded at the 1st h, 24th h, 48th h, 72nd h, and 120th h respectively. The results showed that the diamondback moth larvae in the Control group and SO PKEG group grew normally at each time point, and the survival rate was 100%. However, the diamondback moth larvae in the MOPKEG group stopped wriggling at the 1st h, showed no response after being touched by a brush multiple times, and no longer fed. The survival rate of each group was 0. The results indicated that MO PKEG had an obvious killing effect on diamondback moth larvae( Figure 7 A - B). Photos were taken at the last time point to record and simulate the leaf feeding situation of each group( Figure 7 C), and the results were as Figure 7 shown in D. The feeding rate of the Conrol group was 68.13±14.89% at 120 h, and that of the SO PKEG group was 70.22±15.88% at 120 h. Compared with the Control and SO PKEG groups, the diamondback moth in the MOPKEG group showed an obvious low feeding rate, and the feeding rate at 120 h was only 14.09±4.11% (P<0.01).

[0058] The present invention uses food-grade solid particles as emulsifiers. Compared with the chemically synthesized emulsifiers used in traditional emulsions, Pickering emulsion gels are safer, biodegradable, and environmentally friendly. At the same time, it can control the size and distribution of oil droplets, providing fine regulation for the physical properties and application performance of the emulsion. These comprehensive advantages make Pickering emulsion gels a highly promising emulsion system in the fields of food, cosmetics, and pesticide delivery, etc.

[0059] In summary, the mustard oil Pickering emulsion gel prepared by the present invention has certain attractiveness and lethality to Plutella xylostella, and is an environmentally friendly and efficient green pesticide. Its preparation process is simple, green and environmentally friendly, with high safety and stability, and is easily degraded by the environment. It can significantly improve pesticide efficiency and reduce environmental impact, and has broad application prospects.

Claims

1. Use of mustard oil in the preparation of a pesticide for controlling the diamondback moth, a cruciferous pest.

2. A Pickering emulsion gel containing mustard oil, characterized in that: It is prepared from the following raw materials in volume ratio: 3 - 7 parts of zein - tannic acid nano - sodium alginate composite particles, 3 - 6 parts of soybean oil, 1 - 3 parts of mustard oil; In the zein - tannic acid nano - sodium alginate composite particles, the concentration of zein is 0.5 - 4%, and the concentration of sodium alginate is 0.1 - 2%; The zein - tannic acid nano - sodium alginate composite particles are prepared from the following raw materials in weight ratio: 1 - 6 parts of zein, 1 - 2 parts of tannic acid, 1 - 3 parts of sodium alginate.

3. The Pickering emulsion gel containing mustard oil according to claim 2, wherein: It is prepared from the following raw materials in volume ratio: 5 parts of zein - tannic acid nano - sodium alginate composite particles, 4 parts of soybean oil, 1 part of mustard oil; In the zein - tannic acid nano - sodium alginate composite particles, the concentration of zein is 2%, and the concentration of sodium alginate is 1%; The zein - tannic acid nano - sodium alginate composite particles are prepared from the following raw materials in weight ratio: 4 parts of zein, 1.2 parts of tannic acid, 2 parts of sodium alginate.

4. The Pickering emulsion gel containing mustard oil according to claim 2 or 3, characterized in that: The zein - tannic acid nano - sodium alginate composite particles are prepared by the anti - solvent precipitation method and the method of mixed magnetic stirring.

5. The Pickering emulsion gel containing mustard oil according to claim 4, characterized in that: The preparation method of the zein - tannic acid nano - sodium alginate composite particles is as follows: a. Weigh the raw materials in each weight ratio; b. Dissolve zein in an ethanol solution, then add tannic acid, and after dissolution, obtain a zein / tannic acid ethanol solution; c. Inject the fully dissolved zein / tannic acid ethanol solution into water, stir magnetically and heat to remove the alcohol, and obtain zein / tannic acid nanoparticles; d. Add sodium alginate to the zein / tannic acid nanoparticles, stir for 3 - 6 h, and obtain zein - tannic acid nano - sodium alginate composite particles.

6. The Pickering emulsion gel containing mustard oil according to claim 5, characterized in that: The ethanol solution in step b is a 65 - 80% ethanol aqueous solution; the mass - volume ratio of zein to the ethanol solution is 5 - 40 g:1 L; The stirring conditions in step c are: rotation speed 600 - 800 r / min, temperature 40 - 60 °C, stirring time 2 - 4 h; In d, the addition ratio of sodium alginate is 1%, rotation speed 600 - 800 r / min, temperature 20 - 30 °C, stirring time 3 - 6 h.

7. A method for preparing a Pickering emulsion gel containing mustard oil according to any one of claims 2-6, characterized in that: It includes the following steps: After uniformly mixing the zein - tannic acid nano - sodium alginate composite particles and the oil phase, shear at a speed of 10000 - 25000 r / min for 1 - 5 min to obtain a Pickering emulsion gel.

8. Use of the Pickering emulsion gel containing mustard oil according to any one of claims 2 - 6 in the preparation of a pesticide for controlling the diamondback moth, a cruciferous pest.

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