Temperature-responsive pesticide system based on liquid-liquid condensed phase and wormlike micelle transformation as well as preparation and application of temperature-responsive pesticide system

Abstract

The invention discloses a temperature response type pesticide system based on liquid-liquid condensed phase and wormlike micelle transformation and preparation and application of the temperature response type pesticide system based on liquid-liquid condensed phase and wormlike micelle transformation. The pesticide composition comprises 8-hydroxy-1, 3, 6-pyrene trisulfonic acid trisodium salt (HPTS) and a cationic surface active agent. The system disclosed by the invention is in a liquid-liquid condensed phase state at a relatively high temperature, has excellent encapsulation capacity on emamectin benzoate pesticide, is in a wormlike micelle state at a low temperature, and can release the encapsulated pesticide.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature-responsive pesticide systems, and specifically relates to a temperature-responsive pesticide system and its preparation and application, and also specifically relates to a temperature-responsive pesticide system based on the transition between liquid-liquid condensed phase and worm-like micelles and its preparation and application. Background Art

[0002] Pesticides are an integral part of agricultural production, playing a vital role in protecting crops from pests, diseases, and weeds. Their use can offset 30-40% of global crop yield losses. However, the impact of widespread pesticide use on the ecological environment cannot be ignored. Stimuli-responsive pesticide systems are crucial for improving pesticide utilization, controlling residual contamination, and protecting food and ecological safety. Temperature is a key factor influencing crop pest occurrence and pesticide efficacy. Existing temperature-responsive pesticide systems are mostly intelligent pesticide release systems designed for high temperatures. However, Noctuidae pests, such as the cotton bollworm and the beet armyworm, are more active at night when temperatures are relatively cooler. Therefore, developing intelligent pesticide release systems at low temperatures to target Noctuidae and other pests that are more active at low temperatures could improve pesticide efficacy and reduce the ecological damage caused by pesticide overuse, holding great research potential. Summary of the Invention

[0003] In response to the shortcomings and deficiencies of the prior art, the present invention provides a temperature-responsive pesticide system. Changing the temperature causes the pesticide system to undergo a transition between worm-like micelles and a liquid-liquid coacervate phase, enabling better release of the encapsulated pesticide at temperatures ≤25°C. Furthermore, the pesticide system can deposit and spread well on both hydrophilic and hydrophobic plant leaves. The system has the advantages of a simple preparation process, the ability to respond to low-temperature stimuli, and the ability to spread well on both hydrophilic and hydrophobic leaves. Liquid-liquid phase separation is the spontaneous separation of a homogeneous colloidal solution in an aqueous solution into two immiscible phases: one phase is the liquid-liquid coacervate phase, which is rich in colloidal components; the other phase is a dilute phase, which contains less colloidal components and is in equilibrium with it.

[0004] Based on this, the technical solution of the present invention is as follows:

[0005] A pesticide composition comprises 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) and a cationic surfactant.

[0006] According to an embodiment of the present invention, the cationic surfactant is dodecylmethyldihydroxyethylammonium bromide (DDHAB).

[0007] According to an embodiment of the present invention, the molar ratio of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) to the cationic surfactant is 1:1-5, preferably 1:1-2, for example 2:3.

[0008] According to an embodiment of the present invention, the concentration of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) is 5.0-15.0 mM, for example, 5.0 mM, 6.0 mM, 8.0 mM, 10.0 mM, 12.0 mM, 14.0 mM or 15.0 mM.

[0009] According to an embodiment of the present invention, the concentration of the cationic surfactant is 10.0-25.0 mM, for example, 10.0 mM, 12.0 mM, 15.0 mM, 18.0 mM, 20.0 mM, 22.0 mM or 25.0 mM.

[0010] According to an embodiment of the present invention, the pesticide composition further comprises a pesticide active ingredient, preferably a hydrophobic pesticide active ingredient, such as emamectin benzoate.

[0011] According to an embodiment of the present invention, the concentration of emamectin benzoate in the pesticide composition is 0.1-5.0 mg / L, for example, 0.1 mg / L, 0.3 mg / L, 0.5 mg / L, 1.0 mg / L, 1.2 mg / L, 1.5 mg / L, 2.0 mg / L, 2.5 mg / L, 3.0 mg / L, 3.5 mg / L, 4.0 mg / L, 4.5 mg / L or 5.0 mg / L.

[0012] According to an embodiment of the present invention, the pesticide composition further comprises water.

[0013] According to an embodiment of the present invention, the pesticide composition consists of emamectin benzoate, 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS), dodecylmethyldihydroxyethylammonium bromide (DDHAB) and water;

[0014] The molar ratio of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) to the cationic surfactant is 1:1-5;

[0015] Preferably, the concentration of the 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) is 5 to 15 mM, and / or the concentration of the dodecylmethyldihydroxyethylammonium bromide (DDHAB) is 10 to 25 mM, and / or the concentration of the emamectin benzoate is 0.1-5.0 mg / L.

[0016] According to an embodiment of the present invention, the temperature-responsive pesticide system is in a worm-like micelle state at a temperature of ≤25° C. (eg, 5-25° C.) and a humidity of 40-60%.

[0017] According to an embodiment of the present invention, the temperature-responsive pesticide system is in a liquid-liquid condensed phase state at a temperature greater than 25° C. (eg, 26-40° C.) and a humidity of 40-60%.

[0018] The present invention also provides a method for preparing the above pesticide composition, which comprises:

[0019] 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) and a cationic surfactant are mixed to obtain the pesticide composition.

[0020] According to an embodiment of the present invention, the solvent used in the mixing is water.

[0021] According to an embodiment of the present invention, the concentration of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) in water is 2.0-15.0 mM, preferably 5.0-15.0 mM.

[0022] According to an embodiment of the present invention, the concentration of the cationic surfactant in water is 10-25 mM, preferably 12.0-18.0 mM.

[0023] According to an embodiment of the present invention, the preparation method of the pesticide composition is:

[0024] 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS), a cationic surfactant and emamectin benzoate are mixed to obtain the pesticide composition.

[0025] According to an embodiment of the present invention, the mixing temperature is 20-40°C, for example, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C or 40°C;

[0026] The mixing time is 6-24 hours, preferably 8-14 hours.

[0027] The present invention also provides application of the temperature-responsive pesticide composition in insecticides.

[0028] Preferably, the insect is a pest of the family Noctuidae, such as Heliothis armigera or Spodoptera exigua.

[0029] Beneficial effects of the present invention:

[0030] The present invention provides a temperature-responsive pesticide system, a preparation method, and an application thereof. The system is prepared by mixing 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) and a cationic surfactant, dodecylmethyldihydroxyethylammonium bromide (DDHAB). The system is in a liquid-liquid condensed phase state at relatively high temperatures, and has excellent encapsulation capacity for emamectin benzoate pesticide, while in a worm-like micelle state at low temperatures, which can release the encapsulated pesticide. Compared with commercial emamectin benzoate suspension concentrates, the pesticide system exhibits better insecticidal effects against cotton bollworm and beet armyworm at lower temperatures, and can exhibit excellent deposition and spreading effects on both hydrophilic cotton leaves and hydrophobic cabbage leaves, and has important practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 (a) is a cryo-TEM image of the HPTS / DDHAB system at 25°C and (b) is a cryo-SEM image of the HPTS / DDHAB system at 30°C in Example 1.

[0032] Figure 2 The figure shows the encapsulation effect of the HPTS / DDHAB condensed phase of Example 1 on emamectin benzoate pesticides with different initial concentrations, as tested by high performance liquid chromatography.

[0033] Figure 3 The half-lethal concentration statistics of Examples 1-3 and Comparative Examples 1-2 against Heliothis cotton bollworm and Spodoptera exigua.

[0034] Figure 4 The impact and spreading of water and the HPTS / DDHAB coacervate phase in Example 1 on the hydrophilic cotton leaves and the hydrophobic cabbage leaves. DETAILED DESCRIPTION

[0035] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0036] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0037] In the following examples and comparative examples, the median lethal concentration of the larvae was obtained by the following method:

[0038] The bioactivity of the pesticide system against Heliothis armigera and Spodoptera exigua was tested using the leaf dip method. Cut leaves were dipped in the test pesticide solution for 10 seconds, removed and air-dried, and placed in a Petri dish containing filter paper. Ten test insects were then inoculated and placed in a repeat three times. The treated insects were then housed and observed under a temperature of 25°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. After 48 hours, larval mortality was calculated using the following formula.

[0039] The half-lethal concentration was calculated by SPSS software based on the mortality rate of larvae at different concentrations.

[0040]

[0041] where K is the number of dead larvae and N is the total number of larvae treated.

[0042] Example 1

[0043] 10.0 mM HPTS and 15.0 mM DDHAB were added to water to prepare a mixed solution with a molar ratio of HPTS:DDHAB = 2:3. The emamectin benzoate pesticide was added to the mixed solution at 40°C, and the drug-containing solution was prepared according to a certain concentration gradient of the active ingredient (0.313, 0.625, 1.250, 2.500, 5.000 mg / L). The resulting solution was maintained at 35°C for 12 hours to obtain a temperature-responsive pesticide system.

[0044] Cotton leaves were cut into circular pieces and immersed in the above solution for 10 seconds, then removed, air-dried, and placed in a porous Petri dish lined with filter paper. Ten third-instar larvae of the cotton bollworm were inoculated, with a pure water group serving as a control. Each group was replicated three times. The treated insects were reared for 48 hours at a temperature of 25°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. Mortality was then measured. The median lethal concentration (LC50) for cotton bollworm larvae was calculated based on larval mortality at different concentrations.

[0045] In a similar manner, cabbage leaves were dipped into a series of HPTS / DDHAB solutions containing emamectin benzoate at different concentrations (0.156, 0.313, 0.625, 1.250, 2.500 mg / L) and their median lethal concentrations against beet armyworm larvae were tested.

[0046] Under the condition of 35° C., the LC50 of Example 1 to the larvae of Heliothis armigera was 1.401 mg / L, and the LC50 to the larvae of Spodoptera exigua was 1.065 mg / L.

[0047] Figure 1(a) shows a cryo-transmission electron microscopy image of the HPTS / DDHAB system in Example 1 at 25°C and a cryo-scanning electron microscopy image at 30°C. At 25°C, HPTS / DDHAB is in a worm-like micelle state; above 25°C, for example, at 30°C, the system enters a coacervate phase, which effectively encapsulates the pesticide. This property enables HPTS / DDHAB to release the pesticide at relatively low temperatures, achieving better insecticide efficacy.

[0048] Figure 2 The HPTS / DDHAB coacervate phase exhibited good encapsulation efficiency for emamectin benzoate at different initial concentrations, as determined by HPLC in Example 1. The HPTS / DDHAB liquid-liquid coacervate phase exhibited excellent encapsulation efficiency for emamectin benzoate at different initial concentrations, with encapsulation rates exceeding 98%.

[0049] Figure 4 Figure 3. The impact and spreading of water and HPTS / DDHAB coacervates on hydrophilic cotton and hydrophobic cabbage leaves. The HPTS / DDHAB coacervate system exhibited superior deposition and spreading compared to water on both hydrophilic cotton and hydrophobic cabbage leaves. In particular, water failed to fully deposit on the hydrophobic cabbage leaves, while HPTS / DDHAB did. This characteristic is beneficial for improving pesticide utilization during application.

[0050] Example 2

[0051] A mixed solution with a molar ratio of 2:3 was prepared by adding 10.0 mM HPTS and 15.0 mM DDHAB to water. Emamectin benzoate was then added to the solution at 40°C, following a concentration gradient (0.313, 0.625, 1.250, 2.500, and 5.000 mg / L). The resulting solution was maintained at 30°C for 12 hours to create a temperature-responsive pesticide system.

[0052] Cotton leaves were cut into discs and immersed in the above solution for 10 seconds before removal. After drying, they were placed in a porous Petri dish lined with filter paper and inoculated with 10 third-instar larvae of Spodoptera armigera. A pure water group served as a control, and each group was replicated three times. The treated insects were reared for 48 hours at a temperature of 25°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. Mortality was then measured. The median lethal concentration (LC50) for Spodoptera armigera larvae was calculated based on larval mortality at different concentrations.

[0053] In a similar manner, cabbage leaves were dipped into a series of HPTS / DDHAB solutions containing emamectin benzoate at different concentrations (0.156, 0.313, 0.625, 1.250, 2.500 mg / L) and their median lethal concentrations against beet armyworm larvae were tested.

[0054] Under the condition of 30° C., the LC50 of Example 2 to the larvae of Heliothis armigera was 1.143 mg / L, and the LC50 to the larvae of Spodoptera exigua was 0.903 mg / L.

[0055] Example 3

[0056] A mixed solution with a molar ratio of 2:3 was prepared by adding 10.0 mM HPTS and 15.0 mM DDHAB to water. Emamectin benzoate was then added to the solution at 40°C, following a concentration gradient (0.313, 0.625, 1.250, 2.500, and 5.000 mg / L). The resulting solution was maintained at 25°C for 12 hours to create a temperature-responsive pesticide system.

[0057] Cotton leaves were cut into discs and immersed in the solution for 10 seconds before removal. After drying, the discs were placed in a porous Petri dish lined with filter paper and inoculated with 10 third-instar larvae of Spodoptera cotton bollworm. A pure water group served as a control, and each group was replicated three times. The treated insects were reared for 48 hours at a temperature of 25°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. Mortality was then measured. The median lethal concentration (LC50) for Spodoptera cotton bollworm larvae was calculated based on larval mortality at different concentrations.

[0058] In a similar manner, cabbage leaves were dipped into a series of HPTS / DDHAB solutions containing emamectin benzoate at different concentrations (0.156, 0.313, 0.625, 1.250, 2.500 mg / L) and their median lethal concentrations to beet armyworm larvae were tested.

[0059] Under the condition of 25° C., the LC50 of Example 3 to the larvae of Heliothis armigera was 0.807 mg / L, and the LC50 to the larvae of Spodoptera exigua was 0.576 mg / L.

[0060] Comparative Example 1

[0061] A commercial emamectin benzoate suspension solution was prepared at a concentration gradient (0.313, 0.625, 1.250, 2.500, and 5.000 mg / L). The resulting solution was maintained at 25°C for 12 hours. Cotton leaves were cut into discs, immersed in the solution for 10 seconds, removed, air-dried, and placed in a porous Petri dish lined with filter paper. Ten third-instar larvae of the cotton boll moth were inoculated. A pure water group served as a control, and each group was replicated three times. The treated insects were reared for 48 hours at a temperature of 25°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. Mortality was then measured. The median lethal concentration (LC50) for cotton boll moth larvae was calculated based on larval mortality at different concentrations.

[0062] In a similar manner, cabbage leaves were dipped into a series of commercial suspension concentrate solutions of emamectin benzoate pesticide with different active ingredient concentrations (0.156, 0.313, 0.625, 1.250, 2.500 mg / L) and then tested for their median lethal concentrations against beet armyworm larvae.

[0063] Under the condition of 25° C., the LC50 of Comparative Example 1 to the larvae of Spodoptera exigua was 0.873 mg / L, and the LC50 to the larvae of Spodoptera exigua was 0.640 mg / L.

[0064] Comparative Example 2

[0065] A commercial emamectin benzoate suspension solution was prepared at a concentration gradient (between 0.313, 0.625, 1.250, 2.500, and 5.000 mg / L). The resulting solution was maintained at 35°C for 12 hours. Cotton leaves were cut into discs, immersed in the solution for 10 seconds, removed, and air-dried. The discs were then placed in a porous Petri dish lined with filter paper and inoculated with 10 third-instar larvae of the cotton boll moth. A pure water group served as a control. Each group was replicated three times. The treated insects were reared for 48 hours at a temperature of 35°C, a humidity of 55%, and a photoperiod of L:D = (14:10) h. Mortality was then measured.

[0066] In a similar manner, cabbage leaves were dipped into a series of commercial suspension concentrate solutions of emamectin benzoate pesticide with different active ingredient concentrations (0.156, 0.313, 0.625, 1.250, 2.500 mg / L) and then tested for their median lethal concentrations against beet armyworm larvae.

[0067] Under the condition of 35°C, the LC50 of Comparative Example 2 to the larvae of Spodoptera exigua was 0.876 mg / L, and the LC50 to the larvae of Spodoptera exigua was 0.631 mg / L.

[0068] Table 1 Statistics of the mortality of Heliothis cotton bollworm killed by pesticides in Examples and Comparative Examples

[0069]

[0070] Table 2 Statistics of the mortality rate of beet armyworm killed by pesticides in Examples and Comparative Examples

[0071]

[0072]

[0073] Taking the mortality rate of 0.156 (mg / L) in Table 1 as an example, the three groups of data represent three parallel data under the same conditions.

[0074] The above is an exemplary description of the embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A pesticide composition, characterized in that The invention comprises 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt and a cationic surfactant.

2. The composition according to claim 1, characterized in that The cationic surfactant is dodecylmethyldihydroxyethylammonium bromide.

3. The composition according to claim 1, characterized in that The molar ratio of the trisodium salt of 8-hydroxy-1,3,6-pyrenetrisulfonic acid to the cationic surfactant is 1:1-5.

4. The composition according to claim 1, characterized in that The active ingredient of the composition is emamectin benzoate; The concentration of emamectin benzoate in the total content of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt and cationic surfactant is 0.1-5.0 mg / L.

5. The composition according to claim 1, characterized in that The temperature-responsive pesticide system is in a worm-like micelle state at a temperature of ≤25°C and a humidity of 40-60%; The temperature-responsive pesticide system is in a liquid-liquid condensed phase state when the temperature is greater than 25° C. and the humidity is 40-60%.

6. The method for preparing the composition according to any one of claims 1 to 5, characterized in that: The method is: The pesticide composition is obtained by mixing 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt and a cationic surfactant.

7. The method according to claim 6, characterized in that The solvent used in the mixing is water; The concentration of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt in water is 2.0-15.0 mM; The concentration of the cationic surfactant in water is 10.0-25.0 mM.

8. The method according to claim 6, characterized in that The preparation method of the pesticide composition is: The pesticide composition is obtained by mixing 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt, a cationic surfactant and emamectin benzoate.

9. Use of the composition according to any one of claims 1 to 5 in insecticides.

10. The use according to claim 9, characterized in that The insects are pests of the family Noctuidae.

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