Bemisia tabaci repellent spray and preparation method thereof

Abstract

The invention discloses environment-friendly bemisia tabaci repellent spray as well as a preparation method and application thereof. The environment-friendly bemisia tabaci repellent spray is prepared from peppermint oil, lemongrass oil, lavender oil, eucalyptus oil, allicin extract, sophocarpidine, tea saponin, azadirachtin, aloe gel stock solution, a surfactant, glycerol, a pH regulator and deionized water according to a specific weight part ratio. The preparation method comprises the key steps of oil phase preparation, water phase preparation, high-speed emulsification and shearing, high-pressure homogenization, post-addition of active ingredients, pH adjustment and the like. According to the invention, through scientific compounding of various plant essential oils and bioactive components, instant repelling is realized by virtue of strong volatility of the plant essential oils, and the lasting period is prolonged by virtue of a continuous physiological interference effect of alkaloid. The prepared spraying agent is uniform in particle size and stable in system, has a remarkable repelling effect on bemisia tabaci (the repelling rate in 24 hours is larger than or equal to 85%), is safe to crops and harmless to human, livestock and the environment, and provides a brand new solution for green prevention and control of bemisia tabaci.

Description

Technical Field

[0001] This invention belongs to the field of green pest control technology in agriculture, specifically relating to an environmentally friendly whitefly repellent spray with multi-component synergistic effects, its preparation method, and its application. Background Technology

[0002] Whiteflies are a major invasive agricultural pest in my country, and their control has long faced severe challenges. Currently, agricultural production mainly relies on chemical pesticides for control, but this has led to increasingly serious pesticide resistance in pests. Reports indicate that whiteflies have developed varying degrees of resistance to many chemical pesticides, including organophosphates, pyrethroids, carbamates, neonicotinoids, and insect growth regulators. Simultaneously, pesticide residues pose a significant threat to food safety, the ecological environment, and non-target organisms such as pollinating insects. To address these issues, the industry has attempted to develop some environmentally friendly repellents based on plant essential oils. However, these products often have significant limitations in practical applications: their formulations are relatively simple, their target sites are limited, resulting in short-lived and unsatisfactory repellent effects. Furthermore, due to the complexity of the active ingredients and their significant differences in physicochemical properties, technical bottlenecks such as system instability, easy stratification, and easy degradation of active ingredients are frequently encountered during formulation, seriously affecting the product's shelf life and field efficacy. Therefore, there is an urgent need to develop a whitefly control formulation with high repellent activity, long-lasting effect, environmental friendliness, and excellent formulation stability to compensate for the shortcomings of existing technologies. Summary of the Invention

[0003] To address the above problems, this invention provides a whitefly repellent spray and its preparation method.

[0004] This invention scientifically combines various plant essential oils with repellent and inhibitory effects with bioactive components to construct a multi-target synergistic system. This system not only utilizes the strong volatile odors of plant essential oils for immediate repellency but also interferes with the feeding, growth, and oviposition behaviors of whiteflies through the sustained physiological effects of alkaloids such as matrine and azadirachtin, thus achieving a combination of rapid and sustained efficacy. Its water-based emulsion system, through the compounding of specific surfactants and optimized preparation processes, stably encapsulates hydrophobic essential oil components with hydrophilic active substances, promoting efficient delivery and uniform distribution of the active ingredients, forming a long-lasting protective layer on the leaf surface, and extending the duration of effectiveness.

[0005] Another objective of this invention is to provide a method for preparing the aforementioned repellent spray. This method ensures good reproducibility of the preparation process, high batch-to-batch stability of the product, and uniform particle size and stable system of the resulting spray by precisely controlling core process parameters such as the pretreatment temperature of the oil and aqueous phases, the shear rate and time of high-speed emulsification, and the order of subsequent addition of key active ingredients. This facilitates the transition from laboratory to large-scale production.

[0006] Another objective of this invention is to provide the application of the above-mentioned repellent spray in the control of whiteflies on crops, particularly in the treatment of economic crops such as greenhouse tomatoes, cucumbers, and eggplants. This product only needs to be diluted with water and sprayed evenly on both sides of the plant leaves at the early stage of whitefly infestation to achieve highly effective repellency and control. It is safe for crops and harmless to humans, animals, and the environment.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A method for preparing a whitefly repellent spray includes the following steps: (1) Prepare the raw materials, which include, by weight: 8-15 parts peppermint oil, 10-20 parts lemongrass oil, 5-12 parts lavender oil, 3-8 parts eucalyptus oil, 2-5 parts allicin extract, 1-3 parts matrine, 4-10 parts tea saponin, 2-6 parts azadirachtin, 15-30 parts aloe vera gel stock solution, 3-8 parts surfactant, 5-10 parts glycerin, 0.1-0.5 parts pH adjuster, and deionized water to 100 parts; (2) Oil phase preparation: peppermint oil, lemongrass oil, lavender oil and eucalyptus oil are mixed at 35-45℃ and stirred at 300-500 rpm for 15-25 minutes to obtain a homogeneous oil phase mixture. (3) Aqueous phase preparation: In another reactor, add deionized water, aloe vera gel stock solution, glycerin, tea saponin, matrine and surfactant, heat to 40-50℃, stir at 400-600 rpm until all components are completely dissolved to obtain an aqueous phase mixture; (4) Emulsification and mixing: At a speed of 8000-12000 rpm, the oil phase mixture obtained in step (2) is slowly added to the water phase mixture obtained in step (3), and shearing is continued for 10-20 minutes to form a primary emulsion. (5) Fine homogenization and post-addition: Homogenize the colostrum 2-3 times under a pressure of 25-35MPa using a high-pressure homogenizer. Then add allicin extract and azadirachtin to the homogenized emulsion and stir at a low speed of 200-400rpm for 30-45 minutes to make it evenly mixed. (6) Adjustment and filling: Add pH adjuster to the product obtained in step (5) to adjust the pH value to 6.0-7.0, let it stand to defoam, filter, and fill to obtain the whitefly repellent spray.

[0009] Furthermore, in the above preparation method, the allicin extract is an oleoresin obtained by cold pressing fresh garlic.

[0010] Furthermore, in the above preparation method, the weight ratio of matrine to azadirachtin is 1:(1.5-3).

[0011] Furthermore, in the above preparation method, the surfactant in step (1) is a compound of alkyl glycoside (APG) and sorbitan monooleate polyoxyethylene ether (Tween-80), with a compound weight ratio of alkyl glycoside: Tween-80 = (1.5-3): 1.

[0012] Furthermore, in the above preparation method, the pH adjuster in step (1) is an aqueous solution of citric acid and / or sodium citrate.

[0013] The present invention also discloses a whitefly repellent spray prepared by the above preparation method.

[0014] Furthermore, the above-mentioned whitefly repellent spray has a particle size distribution D90 ≤ 5μm and an appearance of a translucent to milky white liquid.

[0015] Furthermore, the above-mentioned whitefly repellent spray has a viscosity of 10-50 mPa•s at 25°C and its stability meets the requirement of no obvious stratification, precipitation, or deterioration after 14 days of storage at 54°C±2°C.

[0016] Furthermore, the above-mentioned whitefly repellent spray has a repellency rate of not less than 85% against whiteflies within 24 hours after application, and is safe for crops without causing phytotoxicity.

[0017] This invention also discloses a method for controlling whiteflies, wherein the whitefly repellent spray is diluted with water 50-200 times and then evenly sprayed on both sides of crop leaves at the early stage of whitefly infestation. The application interval is 7-14 days, and it is harmless to humans, animals and the environment when used within the safe harvest interval.

[0018] Compared with existing technologies, the present invention has the following advantages and beneficial effects: First, all components are derived from plants or bio-fermentation products, are biodegradable, and safe for the environment and non-target organisms (such as bees), achieving true green environmental protection. Second, by scientifically compounding various plant essential oils with different mechanisms of action with bioactive ingredients, a significant synergistic effect is produced. It not only has good rapid repellency but also persistently interferes with the feeding and oviposition behavior of whiteflies, effectively overcoming the short-lasting effect of traditional plant-derived preparations. Finally, through optimized preparation processes and a specific surfactant system, hydrophobic and hydrophilic active substances are successfully and stably integrated into a water-based emulsion system. The product has high stability, is easy to use, and is easy to scale up for production, showing promising market application prospects. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. All raw materials used in the embodiments of this invention are commercially available.

[0020]

[0021] Example 1 An environmentally friendly whitefly repellent spray, made from the following raw materials in parts by weight: Peppermint oil 8 parts, lemongrass oil 10 parts, lavender oil 5 parts, eucalyptus oil 3 parts, allicin extract 2 parts, matrine 1 part, tea saponin 4 parts, azadirachtin 2 parts, aloe vera gel stock solution 15 parts, alkyl glycoside (APG) 1.2 parts, Tween-80 0.8 parts, glycerin 5 parts, citric acid 0.1 parts, deionized water to 100 parts; The allicin extract is an oleoresin obtained by cold pressing fresh garlic.

[0022] Its preparation method includes the following steps: (1) Oil phase preparation: peppermint oil, lemongrass oil, lavender oil and eucalyptus oil were mixed at 35°C and stirred at 300 rpm for 25 minutes to obtain a homogeneous oil phase mixture; (2) Aqueous phase preparation: In another reactor, deionized water, aloe vera gel stock solution, glycerin, tea saponin, matrine, alkyl glycoside (APG) and Tween-80 are added, heated to 40°C, and stirred at 400 rpm until all components are completely dissolved to obtain an aqueous phase mixture. (3) Emulsification and mixing: The oil phase mixture obtained in step (1) is slowly added to the water phase mixture obtained in step (2) at a high speed of 8000 rpm in a high-speed shearing machine, and shearing is continued for 20 minutes to form a primary emulsion; (4) Fine homogenization and post-addition: The colostrum was homogenized three times under a pressure of 25 MPa using a high-pressure homogenizer. Then, allicin extract and azadirachtin were added to the homogenized emulsion and stirred at a low speed of 200 rpm for 45 minutes to make it evenly mixed. (5) Adjustment and filling: Add citric acid to the product obtained in step (4), adjust the pH value to 6.0, let it stand to defoam, filter, and fill to obtain the whitefly repellent spray.

[0023] Example 2 An environmentally friendly whitefly repellent spray, made from the following raw materials in parts by weight: 12 parts peppermint oil, 15 parts lemongrass oil, 8 parts lavender oil, 5 parts eucalyptus oil, 3.5 parts allicin extract, 2 parts matrine, 7 parts tea saponin, 4 parts azadirachtin, 22 parts aloe vera gel stock solution, 2.1 parts alkyl glycoside (APG), 0.9 parts Tween-80, 7 parts glycerin, 0.3 parts sodium citrate, and deionized water to a total of 100 parts; The allicin extract is an oleoresin obtained by cold pressing fresh garlic.

[0024] Its preparation method includes the following steps: (1) Oil phase preparation: peppermint oil, lemongrass oil, lavender oil and eucalyptus oil were mixed at 40°C and stirred at 400 rpm for 20 minutes to obtain a homogeneous oil phase mixture; (2) Aqueous phase preparation: In another reaction vessel, deionized water, aloe vera gel stock solution, glycerin, tea saponin, matrine, alkyl glycoside (APG) and Tween-80 are added, heated to 45°C, and stirred at 500 rpm until all components are completely dissolved to obtain an aqueous phase mixture. (3) Emulsification and mixing: The oil phase mixture obtained in step (1) is slowly added to the water phase mixture obtained in step (2) at a speed of 10,000 rpm in a high-speed shearing machine, and shearing is continued for 15 minutes to form a primary emulsion; (4) Fine homogenization and post-addition: The colostrum was homogenized twice under a pressure of 30 MPa using a high-pressure homogenizer. Then, allicin extract and azadirachtin were added to the homogenized emulsion and stirred at a low speed of 300 rpm for 38 minutes to make it evenly mixed. (5) Adjustment and filling: Add sodium citrate to the product obtained in step (4), adjust the pH value to 6.5, let it stand to defoam, filter, and fill to obtain the whitefly repellent spray.

[0025] Example 3 An environmentally friendly whitefly repellent spray, made from the following raw materials in parts by weight: 15 parts peppermint oil, 20 parts lemongrass oil, 12 parts lavender oil, 8 parts eucalyptus oil, 5 parts allicin extract, 3 parts matrine, 10 parts tea saponin, 6 parts azadirachtin, 30 parts aloe vera gel stock solution, 2.4 parts alkyl glycoside (APG), 0.6 parts Tween-80, 10 parts glycerin, 0.2 parts citric acid, 0.3 parts sodium citrate, and deionized water to a total of 100 parts; The allicin extract is an oleoresin obtained by cold pressing fresh garlic.

[0026] Its preparation method includes the following steps: (1) Oil phase preparation: peppermint oil, lemongrass oil, lavender oil and eucalyptus oil were mixed at 45°C and stirred at 500 rpm for 15 minutes to obtain a homogeneous oil phase mixture. (2) Aqueous phase preparation: In another reaction vessel, deionized water, aloe vera gel stock solution, glycerin, tea saponin, matrine, alkyl glycoside (APG) and Tween-80 are added, heated to 50°C, and stirred at 600 rpm until all components are completely dissolved to obtain an aqueous phase mixture. (3) Emulsification and mixing: The oil phase mixture obtained in step (1) is slowly added to the water phase mixture obtained in step (2) at a speed of 12000 rpm in a high-speed shearing machine, and shearing is continued for 10 minutes to form a primary emulsion; (4) Fine homogenization and post-addition: The colostrum was homogenized twice under a pressure of 35 MPa using a high-pressure homogenizer. Then, allicin extract and azadirachtin were added to the homogenized emulsion and stirred at a low speed of 400 rpm for 30 minutes to make it evenly mixed. (5) Adjustment and filling: Add a mixed aqueous solution of citric acid and sodium citrate to the product obtained in step (4), adjust the pH value to 7.0, let it stand to defoam, filter, and fill to obtain the whitefly repellent spray.

[0027] Comparative Example 1 A repellent spray, made from the following raw materials in parts by weight: 12 parts peppermint oil, 15 parts lemongrass oil, 8 parts lavender oil, 5 parts eucalyptus oil, 2 parts matrine, 7 parts tea saponin, 4 parts azadirachtin, 22 parts aloe vera gel stock solution, 2.1 parts alkyl glycoside (APG), 0.9 parts Tween-80, 7 parts glycerin, 0.3 parts sodium citrate, and deionized water to 100 parts; (excluding allicin extract).

[0028] The remaining preparation methods are the same as in Example 2.

[0029] Comparative Example 2 A repellent spray, made from the following raw materials in parts by weight: 12 parts peppermint oil, 15 parts lemongrass oil, 8 parts lavender oil, 5 parts eucalyptus oil, 3.5 parts allicin extract, 7 parts tea saponin, 4 parts azadirachtin, 22 parts aloe vera gel stock solution, 2.1 parts alkyl glycoside (APG), 0.9 parts Tween-80, 7 parts glycerin, 0.3 parts sodium citrate, and deionized water to 100 parts; (excluding matrine).

[0030] The remaining preparation methods are the same as in Example 2.

[0031] Comparative Example 3 A repellent spray, made from the following raw materials in parts by weight: 12 parts peppermint oil, 15 parts lemongrass oil, 8 parts lavender oil, 5 parts eucalyptus oil, 3.5 parts allicin extract, 2 parts matrine, 7 parts tea saponin, 22 parts aloe vera gel stock solution, 2.1 parts alkyl glycoside (APG), 0.9 parts Tween-80, 7 parts glycerin, 0.3 parts sodium citrate, and deionized water to 100 parts; (excluding azadirachtin).

[0032] The remaining preparation methods are the same as in Example 2.

[0033] Comparative Example 4 A repellent spray, made from the following raw materials in parts by weight: 12 parts peppermint oil, 15 parts lemongrass oil, 8 parts lavender oil, 5 parts eucalyptus oil, 3.5 parts allicin extract, 2 parts matrine, 7 parts tea saponin, 4 parts azadirachtin, 22 parts aloe vera gel stock solution, 3 parts sodium lauryl sulfate (SDS), 7 parts glycerin, 0.3 parts sodium citrate, and deionized water to 100 parts; (replace the surfactant with chemically synthesized sodium lauryl sulfate).

[0034] The remaining preparation methods are the same as in Example 2.

[0035] Comparative Example 5 A repellent spray, the preparation method of which differs from that of Example 2 is: the high-pressure homogenization process in step (4) is omitted, and the colostrum is directly added and pH adjusted.

[0036] The remaining raw materials and steps are the same as in Example 2.

[0037] Test Example 1 Determination of the repellent effect and persistence of potted plants in greenhouses Objective: To verify the immediate and sustained repellency of the repellent spray of the present invention against whiteflies, and to compare the differences between different embodiments and formulations.

[0038] method: Test insects and plants: Adult whiteflies of a pesticide-sensitive strain were reared in a greenhouse (temperature 25±2℃, relative humidity 60±10%, photoperiod L:D=16h:8h). Tomato seedlings with uniform growth at the 4-leaf-one-heart stage were selected as test plants.

[0039] Test reagents: Prepare samples from Examples 1, 2, 3 and Comparative Examples 1-5, and dilute them 100 times with water for later use. Use an equal volume of water as a blank control.

[0040] Treatment and Inoculation: Using a handheld sprayer, evenly spray the tested pesticide solutions onto both sides of the tomato seedling leaves until they are completely wet but not dripping. Each treatment was repeated 5 times. Tests were conducted 2 hours (immediately) and 7 days (lasting effect) after application.

[0041] Repellency rate determination: The "Y-shaped olfactory instrument method" was used. Tomato leaves treated with the pesticide (target leaves) and untreated, clean tomato leaves (control leaves) were placed on opposite arms of a Y-shaped tube. Thirty healthy, active adult whiteflies were introduced at the main tube entrance and allowed to choose freely. After 15 minutes, the number of whiteflies in each arm was recorded.

[0042] Data statistics: The formula for calculating the avoidance rate is as follows: Repellency rate (%) = [(Number of insects on control leaf surface - Number of insects on target leaf surface) / Total number of insects] × 100% Results are expressed as mean ± standard error. Analysis of variance (ANOVA) was performed using SPSS software, and Duncan's multiple comparisons were performed (P < 0.05).

[0043] Results: See Table 2.

[0044]

[0045] in conclusion: Formulation effectiveness: Examples 1, 2, and 3 all showed extremely high immediate repellency rates of over 90% within 2 hours after application, and there was no significant difference among the three, indicating that within the scope of the claims of this invention, different raw material ratios can achieve excellent initial effects.

[0046] Differences in duration of efficacy: Seven days after application, Examples 2 and 3 showed the best duration of efficacy with no significant difference, while Example 1 showed slightly lower duration of efficacy but still above 80%, indicating a high level of efficacy. This demonstrates that under the optimized formulation (Examples 2 and 3), the product has a longer duration of efficacy.

[0047] Synergistic effect: Comparative Examples 1-3, which lacked allicin extract, matrine, or azadirachtin respectively, showed significantly lower repellency effects, especially in terms of duration, compared to the complete examples (P<0.05). This confirms that the synergistic effect of the multi-component combination is the key to the high efficiency and long-lasting effect of this invention.

[0048] Importance of process and excipients: Comparative Example 4 (with surfactant replacement) and Comparative Example 5 (with simplified process) showed the worst results, which fully demonstrates that the specific surfactant system (APG / Tween-80) and the optimized high-pressure homogenization process used in this invention are indispensable for the formation of stable and efficient formulations.

[0049] Test Example 2 Field efficacy trials Objective: To evaluate the control effect of the repellent spray of the present invention in a real field environment.

[0050] method: Experimental site and crop: A greenhouse cucumber growing area with a history of severe whitefly infestations was selected. The cucumbers were in the mid-growth stage.

[0051] Experimental design: Three treatments were set up: Example 2 (diluted 100 times), Comparative Example 1 (lacking allicin, diluted 100 times), and water control. Each treatment was repeated 3 times in a completely randomized block design.

[0052] Application and Survey: The first spray was carried out at the initial stage of whitefly infestation, followed by a second spray 14 days later. Surveys were conducted before the second spray and 7 and 14 days after the second spray. A five-point sampling method was used in each plot to investigate the number of adult whiteflies on the upper, middle, and lower leaves of 10 cucumber plants.

[0053] Control efficacy calculation: The control effect is calculated based on the insect population reduction rate.

[0054] Results: See Table 3.

[0055]

[0056] Conclusion: In complex field conditions, Example 2 still showed excellent and lasting control effect, significantly better than Comparative Example 1 which lacked the key component allicin, proving that the complete formulation of the present invention has important value in practical applications.

[0057] Test Example 3 Accelerated testing of formulation physical stability Objective: To investigate the physical stability and shelf life of repellent sprays in different embodiments of the present invention.

[0058] method: Test samples: Newly prepared samples of Examples 1, 2, 3, Comparative Example 4 (with surfactant changed) and Comparative Example 5 (without high-pressure homogenization).

[0059] Test conditions: The accelerated test method was adopted according to the "Test Method for Stability of Pesticides at Room Temperature". Each sample was sealed and placed in a constant temperature incubator at 54±2℃ for 14 days to simulate the condition of storage at room temperature (about 25℃) for 2 years.

[0060] Observation and measurement indicators: The following observations were conducted before the start of the experiment and on day 14: Appearance: Observe the color and uniformity of the sample, and whether there is layering, oil separation or precipitation.

[0061] Particle size stability: The particle size distribution (D90) of the emulsion particles was measured using a laser particle size analyzer, and the changes before and after storage were compared. A significant increase indicates that the system is unstable.

[0062] Results: See Table 4.

[0063]

[0064] in conclusion: Stability verification: After accelerated storage at 54°C for 14 days, the samples of Examples 1, 2, and 3 showed uniform appearance, no stratification or precipitation, and minimal changes in the D90 value of the emulsion particle size (all ≤2.3μm). This indicates that under the raw materials and processes defined in the claims of this invention, the products within the entire formulation range have excellent physical stability and can ensure consistent performance throughout the shelf life.

[0065] The key role of surfactants: Comparative Example 4, due to the use of an unsuitable surfactant (SDS), had a large initial particle size and experienced severe stratification and particle size growth after storage, demonstrating that the compound system of alkyl glycoside (APG) and Tween-80 is crucial for the formation and maintenance of nano / submicron stable emulsions.

[0066] Necessity of the process: Comparative Example 5, due to the omission of the high-pressure homogenization step, had an unsatisfactory initial state and completely demulsified after storage, which fully demonstrates that the high-pressure homogenization process is a key step in obtaining a final product with excellent stability and cannot be omitted.

[0067] Test Example 4 Crop safety (phytotoxicity) testing Objective: To verify the safety of the repellent spray of the present invention for crops.

[0068] method: Test crops: Select cucumber and tomato seedlings that are sensitive to the pesticide.

[0069] Test method: Dilute the sample from Example 2 50 times (recommended maximum concentration), 100 times (recommended concentration), and 200 times, and spray evenly on both sides of the seedling leaves. Use water as a control. Five pots were used for each treatment. Observe the leaves for symptoms of phytotoxicity such as scorching, yellowing, and malformation 1 day, 3 days, and 7 days after application.

[0070] Results: Throughout the entire observation period, no visible phytotoxicity symptoms were observed in cucumber and tomato leaves treated with any concentration, showing no difference compared to the water control group.

[0071] Conclusion: The repellent spray of the present invention is safe for crops within the tested concentration range, poses no risk of phytotoxicity, and meets the requirements of green and environmentally friendly products.

[0072] Test Example 5 Preliminary assessment of acute toxicity to non-target organisms Objective: To preliminarily evaluate the acute contact toxicity of the present invention to the Italian honeybee, an important non-target organism in the environment.

[0073] method: Test organism: Healthy Italian honeybee worker bees.

[0074] Test method: The droplet method was used. 0.5 μL of the undiluted solution from Example 2 was directly added to the mesothorax of the bees, with acetone as a control. Each treatment group used 30 bees, and the results were repeated three times. Mortality rates were observed and recorded within 48 hours.

[0075] Results: After 48 hours, the corrected mortality rate of bees in the original solution treatment group of Example 2 was 6.7%. According to the "Environmental Safety Evaluation Criteria for Chemical Pesticides", the oral toxicity of this product is classified as low toxicity.

[0076] Conclusion: The repellent spray of the present invention exhibits low toxicity to honeybees, an important environmental indicator organism, further confirming its environmental friendliness.

[0077] Test Case Summary: Test Example 1 (greenhouse potted plants) showed that Example 2 achieved repellency rates of 94.2% and 86.7% at 2 hours and 7 days after application, respectively, significantly superior to the comparative examples lacking each component. Test Example 2 (field trial) showed that Example 2 achieved field efficacy of 88.5% and 82.1% at 7 and 14 days after application, respectively. Test Example 3 (accelerated stability test) confirmed that all three examples remained homogeneous and stable after 14 days of storage at 54°C, with minimal change in particle size D90 (≤2.3 μm), while comparative examples 4 and 5 showed severe stratification. Furthermore, Test Examples 4 and 5 demonstrated that the product was safe for crops without phytotoxicity and had low toxicity to bees. These quantitative data fully demonstrate the significant advantages of this invention in terms of repellency activity, duration of action, and formulation stability.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention specification, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of the present invention patent.

Claims

1. A method for preparing a whitefly repellent spray, characterized in that, Includes the following steps: (1) Prepare the raw materials, which include, by weight: 8-15 parts peppermint oil, 10-20 parts lemongrass oil, 5-12 parts lavender oil, 3-8 parts eucalyptus oil, 2-5 parts allicin extract, 1-3 parts matrine, 4-10 parts tea saponin, 2-6 parts azadirachtin, 15-30 parts aloe vera gel stock solution, 3-8 parts surfactant, 5-10 parts glycerin, 0.1-0.5 parts pH adjuster, and deionized water to 100 parts; (2) Oil phase preparation: peppermint oil, lemongrass oil, lavender oil and eucalyptus oil are mixed at 35-45℃ and stirred at 300-500 rpm for 15-25 minutes to obtain a homogeneous oil phase mixture. (3) Aqueous phase preparation: In another reactor, add deionized water, aloe vera gel stock solution, glycerin, tea saponin, matrine and surfactant, heat to 40-50℃, stir at 400-600 rpm until all components are completely dissolved to obtain an aqueous phase mixture; (4) Emulsification and mixing: At a speed of 8000-12000 rpm, the oil phase mixture obtained in step (2) is slowly added to the water phase mixture obtained in step (3), and shearing is continued for 10-20 minutes to form a primary emulsion. (5) Fine homogenization and post-addition: Homogenize the colostrum 2-3 times under a pressure of 25-35MPa using a high-pressure homogenizer. Then add allicin extract and azadirachtin to the homogenized emulsion and stir at a low speed of 200-400rpm for 30-45 minutes to make it evenly mixed. (6) Adjustment and filling: Add pH adjuster to the product obtained in step (5) to adjust the pH value to 6.0-7.0, let it stand to defoam, filter, and fill to obtain the whitefly repellent spray.

2. The preparation method according to claim 1, characterized in that, The allicin extract is an oleoresin obtained by cold pressing fresh garlic.

3. The preparation method according to claim 1, characterized in that, The weight ratio of matrine to azadirachtin is 1:(1.5-3.0).

4. The preparation method according to claim 1, characterized in that, The surfactant in step (1) is a compound of alkyl glycoside (APG) and sorbitan monooleate polyoxyethylene ether (Tween-80), with a compound weight ratio of alkyl glycoside: Tween-80 = (1.5-3.0):

1.

5. The preparation method according to claim 1, characterized in that, The pH adjuster in step (1) is an aqueous solution of citric acid and / or sodium citrate.

6. A whitefly repellent spray prepared by the method described in any one of claims 1-5.

7. The whitefly repellent spray according to claim 6, characterized in that, The spray has a particle size distribution D90 ≤ 5μm and an appearance of a translucent to milky white liquid.

8. The whitefly repellent spray according to claim 6, characterized in that, The viscosity of the spray at 25°C is 10-50 mPa·s, and its stability meets the requirement that it can be stored at 54°C±2°C for 14 days without significant stratification, precipitation, or deterioration.

9. The whitefly repellent spray according to claim 6, characterized in that, The spray has a repellency rate of no less than 85% against whiteflies within 24 hours after application, and is safe for crops without causing phytotoxicity.

10. A method for controlling whiteflies, characterized in that, Dilute the whitefly repellent spray according to any one of claims 6-9 with water 50-200 times, and spray it evenly on both sides of crop leaves at the early stage of whitefly infestation, with an application interval of 7-14 days.

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