A UV-resistant nano-pesticide formulation and its application

Abstract

This invention discloses an anti-ultraviolet pesticide formulation with small particle size, uniform distribution, good stability, and excellent anti-ultraviolet function. It can effectively reduce the ultraviolet photolysis of abamectin, which is conducive to prolonging the effective period of the formulation and reducing the overall amount of pesticide used. This conforms to the green control policy of increasing the efficacy and reducing the amount of pesticides used, and provides a new option for the scientific and reduced use of pesticides.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically, it relates to an ultraviolet-resistant nano-pesticide formulation and its application. Background Technology

[0002] Currently, diseases, pests, and weeds pose significant threats to crop growth. Furthermore, after application, pesticide formulations are subject to severe degradation of their active ingredients due to environmental factors, with photochemical degradation being a major form of non-biological degradation. Under photo-oxidative conditions, the rapid degradation of pesticide active substances significantly impacts pest and disease control, drastically reducing pesticide utilization and resulting in pesticide formulations that are costly, expensive, ineffective, and have a short duration of action in field applications.

[0003] Avermectin is a sixteen-membered macrocyclic lactone compound with insecticidal, acaricidal, and nematicidal activities. Its potent insecticidal activity and broad spectrum of activity are groundbreaking. However, avermectin is quite sensitive to ultraviolet light; under light exposure, its molecular structure changes, leading to a decrease or loss of its biological activity. Furthermore, light exposure can trigger oxidation reactions in avermectin, further accelerating its degradation process.

[0004] Spinosad is a macrolide-based, environmentally friendly, and highly effective biological insecticide extracted from the fermentation broth of *Polysporium spinosum*. Its mechanism of action is novel; it can continuously activate nicotinic acetylcholine receptors in target insects. However, its binding site differs from that of nicotinic acid and imidacloprid, and it does not exhibit cross-resistance with current insecticides (chlorantraniliprole group 28 and bromfenac dimethyl ether group 30). It is a low-toxicity, highly effective, and low-residue biological insecticide, possessing both high insecticidal performance and safety for beneficial insects and mammals.

[0005] In addition, traditional pesticide formulations often suffer from problems such as high organic solvent content, poor dispersibility, and short duration of action. Therefore, in order to reduce the photolysis of abamectin or other pesticide components in the formulation, prolong the duration of action of pesticides, and improve the physicochemical properties and delivery efficiency of the formulation, it is necessary to study a new type of pesticide formulation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a UV-resistant nanopesticide formulation with excellent stability and UV resistance.

[0007] In one aspect, the present invention provides an ultraviolet-resistant nano-pesticide formulation, wherein, by mass percentage, the ultraviolet-resistant nano-pesticide formulation comprises 1-5% pesticide compound, 6-8% dispersant, 4-8% light stabilizer, 0.1-0.5% defoamer, 1-5% antifreeze, 0.1-0.5% thickener and deionized water, and the total mass percentage of each component is 100%.

[0008] The pesticide compound includes abamectin; the dispersant is a composition of fatty alcohol polyoxyethylene ether phosphate, organosilicon polyoxyethylene ether, and castor oil polyoxyethylene ether; the light stabilizer is a composition of nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil, with a mass ratio of (2.8–4.5):(0.3–1.4):(4.3–9.0); the defoamer is polydimethylsiloxane; the antifreeze agent is glycerol; and the thickener is xanthan gum.

[0009] Preferably, by mass percentage, the UV-resistant nano-pesticide formulation comprises 1%, 2%, 3%, 4%, or 5% pesticide compound; preferably, by mass percentage, the UV-resistant nano-pesticide formulation comprises 6%, 7%, or 8% dispersant; preferably, by mass percentage, the UV-resistant nano-pesticide formulation comprises 0.1%, 0.2%, 0.3%, 0.4%, or 0.5% defoamer; preferably, by mass percentage, the UV-resistant nano-pesticide formulation comprises 1%, 2%, 3%, 4%, or 5% antifreeze; preferably, by mass percentage, the UV-resistant nano-pesticide formulation comprises 0.1%, 0.2%, 0.3%, 0.4%, or 0.5% thickener.

[0010] In one or more embodiments, the mass ratio of nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in the light stabilizer is (3.6–4.5):(0.8–1.4):(6.7–9.0).

[0011] In one or more embodiments, the light stabilizer comprises nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in a mass ratio of 3.6:0.8:6.7.

[0012] In one or more embodiments, the light stabilizer comprises nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in a mass ratio of 4.5:1.4:9.0.

[0013] In one or more embodiments, the mass ratio of fatty alcohol polyoxyethylene ether phosphate, organosilicon polyoxyethylene ether, and castor oil polyoxyethylene ether in the dispersant is 3:3:2.

[0014] In one or more embodiments, the UV-resistant nanopesticide formulation also includes other pesticide compounds.

[0015] Preferably, the UV-resistant nanopesticide formulation further comprises, by weight percentage, 1%, 2%, 3%, 4%, or 5% other pesticide compounds.

[0016] Preferably, the other pesticide compounds are selected from one or more combinations of spinosad, spirotetramat, flonicamid, spirodiclofen, lambda-cyhalothrin, acetamiprid, methoxyfenozide, and fluopyram.

[0017] In one or more embodiments, the other pesticide compound is spinosad.

[0018] In another aspect, the present invention provides a method for preparing a UV-resistant nanopesticide formulation as described in any embodiment herein, the method comprising the following steps:

[0019] S1: Mix the dispersant, light stabilizer, defoamer, antifreeze and deionized water in proportion, and add pesticide compounds during the mixing process to form a suspension;

[0020] S2: The suspension is subjected to micro-jet high-pressure homogenization;

[0021] S3: Add the thickener to deionized water in proportion and dissolve until clear and transparent to obtain a thickener aqueous solution; under stirring conditions, slowly add the thickener aqueous solution to the high-pressure homogenized suspension, stir and mix evenly to obtain the pesticide formulation.

[0022] In one or more embodiments, in step S2, a multi-channel microfluidic diamond interactive cavity device is selected for high-pressure homogenization, with a homogenization pressure of 22,000 to 27,000 psi and a homogenization flow rate of 90 to 110 mL / min.

[0023] In another aspect, the present invention provides a method for controlling pests, the method comprising applying an ultraviolet-resistant nanopesticide formulation as described in any embodiment herein.

[0024] In another aspect, the present invention provides the application of UV-resistant nanopesticide formulations as described in any embodiment herein in the control of pests.

[0025] Preferably, the pest is a lepidopteran insect; more preferably, the pest is a pyralid moth or a noctuid moth; even more preferably, the pest is a leaf roller or a gray-winged noctuid; even more preferably, the pest is a rice leaf roller or a fall armyworm.

[0026] In another aspect, the present invention provides a light stabilizer for use in pesticide formulations to prevent pesticide photodegradation, characterized in that the light stabilizer is a composition of nano-titanium dioxide, hydrogenated rosin and epoxidized soybean oil, wherein the mass ratio of the three is (2.8-4.5):(0.3-1.4):(4.3-9.0).

[0027] In one or more embodiments, the mass ratio of nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in the light stabilizer is (3.6–4.5):(0.8–1.4):(6.7–9.0).

[0028] In one or more embodiments, the light stabilizer comprises nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in a mass ratio of 3.6:0.8:6.7.

[0029] In one or more embodiments, the light stabilizer comprises nano-titanium dioxide, hydrogenated rosin, and epoxidized soybean oil in a mass ratio of 4.5:1.4:9.0.

[0030] The beneficial effects of this invention are:

[0031] 1. This invention, by adding specific light stabilizers and using a microfluidic high-pressure homogenization preparation process, enables the active ingredients and light stabilizers to be perfectly compatible, giving the formulation product excellent UV resistance, significantly inhibiting the degradation of active ingredients under photo-oxidative conditions, prolonging the duration of pesticide efficacy, reducing the number of pesticide applications, and greatly reducing agricultural production costs.

[0032] 2. This invention uses abamectin and spinosad as active ingredients. By combining them with specific dispersants and employing microfluidic high-pressure homogenization technology, the particle size of the formulation reaches the nanoscale, effectively improving the stability and uniformity of pesticide distribution in the formulation.

[0033] 3. Compared with the prior art, the present invention does not use the conventional wet grinding process in the production process, but adopts the micro-jet high-pressure homogenization preparation process. The process is simple, the energy consumption is greatly reduced, and the final preparation is in liquid form, avoiding the problem of dust flying during use. It is safer for operators and more environmentally friendly. Attached Figure Description

[0034] Figure 1 This is a particle size distribution map of pesticide formulations. Among them, Figure 1 A is the particle size distribution map of UV-resistant pesticide formulation A. Figure 1 B is the particle size distribution map of UV-resistant pesticide formulation C. Figure 1 C is the particle size distribution map of UV-resistant pesticide formulation E. Figure 1 D is the particle size distribution map of pesticide formulation G. Figure 1 E is the particle size distribution map of pesticide formulation H.

[0035] Figure 2 The graph shows the change in photolysis rate over time for UV-resistant pesticide formulations A-E, pesticide formulation F, and pesticide formulation G. Detailed Implementation

[0036] Examples 1-5: UV-resistant pesticide formulations

[0037] In Examples 1-5, UV-resistant pesticide formulations A-E were prepared, with abamectin and spinosad as active ingredients, combined with dispersants, light stabilizers, defoamers, antifreeze agents, thickeners, and deionized water. The mass percentages of each component in UV-resistant pesticide formulation A are shown in Table 1, in UV-resistant pesticide formulation B in Table 2, in UV-resistant pesticide formulation C in Table 3, in UV-resistant pesticide formulation D in Table 4, and in UV-resistant pesticide formulation E in Table 5. The total mass percentage of each component in Tables 1-5 is 100%.

[0038] Pesticide formulation preparation process:

[0039] S1: Fatty alcohol polyoxyethylene ether phosphate, organosilicon polyoxyethylene ether, castor oil polyoxyethylene ether, nano titanium dioxide, hydrogenated rosin, epoxidized soybean oil, polydimethylsiloxane, glycerol and deionized water are stirred and mixed, and abamectin and spinosad are added during the stirring process to form a suspension.

[0040] S2: The obtained suspension was subjected to microfluidic high-pressure homogenization. A multi-channel microfluidic diamond interactive cavity (model: F20Y-7) was selected, with a homogenization pressure of 25000±2000psi and a homogenization flow rate of 100±10mL / min.

[0041] S3: Add xanthan gum to deionized water and dissolve until clear and transparent to obtain a 1% (w / v) xanthan gum aqueous solution; under stirring conditions, slowly add the 1% (w / v) xanthan gum aqueous solution to the suspension after high-pressure homogenization, and stir to mix evenly to obtain the pesticide formulation.

[0042] Table 1: Components and Proportions of UV-resistant Pesticide Formulation A

[0043]

[0044]

[0045] Table 2: Components and proportions of UV-resistant pesticide formulation B

[0046]

[0047] Table 3: Components and Proportions of UV-resistant Pesticide Formulation C

[0048]

[0049] Table 4: Components and Proportions of UV-resistant Pesticide Formulation D

[0050]

[0051]

[0052] Table 5: Components and proportions of UV-resistant pesticide formulation E

[0053]

[0054] Comparative Example 1: Pesticide Formulation F

[0055] Pesticide formulation F was prepared according to the method of Example 3, but pesticide formulation F differs from UV-resistant pesticide formulation C in that it does not contain a light stabilizer. The mass percentages of each component of pesticide formulation F are shown in Table 6 below, and the total mass percentage of each component is 100%.

[0056] Table 6: Components and their proportions of pesticide formulation F

[0057]

[0058] Comparative Example 2: Pesticide Formulation G

[0059] Pesticide formulation G was prepared according to the method in Example 3, but the difference between pesticide formulation G and UV-resistant pesticide formulation C is that the ratio of light stabilizer is 6.3:1.6:3.5. The mass percentages of each component of pesticide formulation G are shown in Table 7 below, and the total mass percentage of each component is 100%.

[0060] Table 7: Components and Proportions of Pesticide Formulation G

[0061]

[0062]

[0063] Comparative Example 3: Pesticide Formulation H

[0064] Pesticide formulation H was prepared according to the components in Example 3. However, the difference between pesticide formulation H and UV-resistant pesticide formulation C is that pesticide formulation H was prepared using conventional wet grinding. The mass percentages of each component in pesticide formulation H are shown in Table 7 below, and the total mass percentage of each component is 100%.

[0065] Example 6: Particle Size Distribution Test

[0066] The particle size distributions of UV-resistant pesticide formulations A-E and F-H were determined using a Zetasizer Lab nanoparticle size potentiometry instrument. The results are as follows: Figure 1 As shown in Table 8, the smaller the average particle size, the more stable the formulation; the smaller the polydispersity index, the more uniform the particle size distribution.

[0067] Depend on Figure 1 As shown in Table 8, the particle sizes of UV-resistant pesticide formulations A to E are relatively small; among them, UV-resistant pesticide formulation C has the smallest particle size and the most uniform particle size distribution, exhibiting excellent stability.

[0068] Table 8: Results of pesticide formulation distribution test

[0069] pesticide formulations Corresponding Examples / Comparative Examples Average particle size (nm) Multi-dispersion index UV-resistant pesticide formulation A Example 1 182.8 0.1705 UV-resistant pesticide formulation B Example 2 188.4 0.2250 UV-resistant pesticide formulation C Example 3 154.0 0.1658 UV-resistant pesticide formulation D Example 4 197.3 0.2405 UV-resistant pesticide formulation E Example 5 181.1 0.2135 Pesticide formulation F Comparative Example 1 218.4 0.2572 Pesticide formulation G Comparative Example 2 403.2 0.2170 Pesticide formulation H Comparative Example 3 1782 0.3079

[0070] Example 7: Photostability Test

[0071] UV-resistant pesticide formulations A-E, pesticide formulation F, and pesticide formulation G were diluted with deionized water to a concentration of 10 mg / L of abamectin and used as test samples. They were then placed into quartz photolysis reaction tubes, the stoppers were tightened, and the outer walls of the tubes were kept clean. The photolysis reaction tubes were placed in a photochemical reaction apparatus for photolysis experiments. A control group was set up, which had the same components as UV-resistant pesticide formulation C and was treated in the same way before being placed in the photochemical reaction apparatus, but was placed in a dark environment.

[0072] The photochemical reaction device includes a light source, which is a xenon lamp (wavelength range of 290nm~800nm) to ensure that the sample receives an ultraviolet intensity of (100±10)μW / cm². 2 (UV intensity was measured at a wavelength of 365 nm), and the reaction temperature was (25 ± 5) °C.

[0073] During the photostability test, water samples were taken periodically to measure the changes in abamectin concentration in each pesticide formulation. Throughout the photolysis experiment, all light sources except the xenon lamp were isolated to minimize their impact on the experimental results. The photostability test results are as follows: Figure 2 As shown, the photolysis rate is calculated by comparing the decrease in avermectin concentration in each test sample at the same time point with the avermectin concentration in the control group. Where t represents time in days, and C represents the concentration of avermectin in the sample or control group at that time.

[0074] Depend on Figure 2 It can be seen that from day 3 to day 28, the photolysis rates of UV-resistant pesticide formulations A to E were consistently significantly lower than those of pesticide formulations F and G.

[0075] Example 8: Field control trial of rice leaf roller

[0076] The experimental site for this embodiment was located in Liantang Town, Nanchang City, Jiangxi Province. The experimental field was flat, with loam soil of moderate fertility, convenient irrigation and drainage, and uniform management, resulting in uniform rice growth. The rice leaf roller, an experimental insect, occurred naturally. The experiment consisted of 9 treatments, with each treatment replicated 4 times, for a total of 36 plots. Each plot was 50 square meters (10 meters × 5 meters) in size, and the plots were arranged in a randomized block design.

[0077] The experiment used UV-resistant pesticide formulations A-C and F-H to apply pesticides to rice leaf rollers from the egg hatching stage to the early larval stage. The experiment was conducted using a spraying method with a 3WD-16-9 ultra-high pressure backpack electric sprayer, using 30-50 kg / mu of water, and applying once. A five-point sampling method was used, with 20 rice plants sampled at each point. The initial insect population was assessed before application, and the number of live insects was assessed 1, 3, 7, and 14 days after application. The insect population reduction rate and control efficacy were calculated. The insect population reduction rate (%) and control efficacy (%) were calculated using the following formula:

[0078]

[0079] The experiment included a blank control group, which received no treatment; and a positive control group, which received 5% (w / v) avermectin-spinosad formulation (total 5%, commercially available). The control efficacy of each formulation is shown in Table 9 below.

[0080] Table 9: Field control efficacy of various formulations against rice leaf roller

[0081]

[0082] As shown in Table 9, UV-resistant pesticide formulations A-C have excellent control effects on rice leaf rollers in the field. The control effect can reach more than 90% at 1, 3, 7 and 14 days after application, with significant effect. Moreover, they have no phytotoxicity or other adverse effects on rice. The control effect is significantly better than pesticide formulations F-H and the positive control of commercially available pesticides.

[0083] Example 9: Field control trial of fall armyworm

[0084] The experimental site for this embodiment was located in Dengxiang Town, Luohe City, Henan Province. The experimental field was flat, with loam soil of moderate fertility, convenient irrigation and drainage, and uniform management. The maize grew uniformly, and the fall armyworm, an experimental pest, occurred naturally. The experiment consisted of 9 treatments, with each treatment replicated 4 times, for a total of 36 plots. Each plot was 50 square meters (10 meters × 5 meters), and the plots were arranged in a randomized block design.

[0085] The experiment used UV-resistant pesticide formulations A-C and F-H to treat fall armyworm larvae in their early stages. The experiment employed a spraying method using a 3WD-16-9 ultra-high pressure backpack electric sprayer, with a water volume of 30-50 kg / mu (approximately 0.067 hectares), and was conducted once. A five-point sampling method was used, with 20 corn plants sampled at each point. The initial insect population was assessed before application, and the number of live insects was assessed at 1, 3, 7, and 14 days after application. The insect population reduction rate and control efficacy were calculated. The insect population reduction rate (%) and control efficacy (%) were calculated using the following formulas:

[0086]

[0087] The experiment included a blank control group, which received no treatment; and a positive control group, which received 5% (w / v) avermectin-spinosad formulation (total 5%, commercially available). The control efficacy of each formulation is shown in Table 10 below.

[0088] Table 10: Field control efficacy of various formulations against fall armyworm

[0089]

[0090] As shown in Table 10, UV-resistant pesticide formulations A-C have excellent control effects on fall armyworm in corn. The control effect can reach more than 85% at 1, 3, 7 and 14 days after application, with significant effect. Moreover, they have no phytotoxicity or other adverse effects on corn. The control effect is significantly better than pesticide formulations F-H and the positive control of commercially available pesticides.

[0091] In summary, the UV-resistant pesticide formulation provided by this invention has a small particle size, uniform distribution, good stability, and excellent UV resistance, effectively reducing the UV photolysis of abamectin. In field trials against rice leaf roller and fall armyworm in corn, the UV-resistant pesticide formulation provided by this invention also showed significantly better control effects than commercially available formulations. The UV-resistant pesticide formulation provided by this invention exhibits significantly less UV photolysis of abamectin, which helps prolong the formulation's effective period and reduces the overall pesticide dosage. This aligns with the green control policy of maximizing pesticide efficacy while reducing dosage, providing a new option for the scientific and reduced use of pesticides.

Claims

1. An anti-UV nano-pesticide formulation, characterized in that, The anti-ultraviolet nano-pesticide preparation consists of 1-5% of the pesticide compound, 6-8% of the dispersant, 4-8% of the light stabilizer, 0.1-0.5% of the defoaming agent, 1-5% of the antifreeze agent, 0.1-0.5% of the thickening agent and deionized water, and the total mass percentage of the components is 100%. The pesticide compound comprises abamectin; the dispersant is a combination of fatty alcohol polyoxyethylene ether phosphate, organosilicon polyoxyethylene ether and castor oil polyoxyethylene ether; the light stabilizer is a combination of nano-titanium dioxide, hydrogenated rosin and epoxy soybean oil, and the mass ratio of the three is (2.8-4.5):(0.3-1.4):(4.3-9.0); the defoaming agent is polydimethylsiloxane; the antifreeze agent is glycerol; and the thickening agent is xanthan gum.

2. The anti-UV nano-pesticide formulation according to claim 1, wherein, The mass ratio of nano-titanium dioxide, hydrogenated rosin and epoxy soybean oil in the light stabilizer is (3.6-4.5):(0.8-1.4):(6.7-9.0).

3. The anti-UV nano-pesticide formulation according to claim 2, wherein, The mass ratio of fatty alcohol polyoxyethylene ether phosphate, organosilicon polyoxyethylene ether and castor oil polyoxyethylene ether in the dispersant is 3:3:

2.

4. The anti-UV nano-pesticide formulation according to any one of claims 1 to 3, characterized in that, The anti-ultraviolet nano-pesticide preparation further comprises other pesticide compounds.

5. The anti-UV nano-pesticide formulation according to claim 4, wherein, The other pesticide compound is spinosad.

6. A method of preparing the anti-UV nano-pesticide formulation according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1: proportionally stirring and mixing the dispersant, the light stabilizer, the defoaming agent, the antifreeze agent and the deionized water, and adding the pesticide compound in the stirring process to form a suspension; S2: performing micro-jet high-pressure homogenization treatment on the suspension; S3: proportionally adding the thickening agent into the deionized water, dissolving until clear and transparent to obtain a thickening agent aqueous solution; under stirring, slowly adding the thickening agent aqueous solution into the suspension subjected to the high-pressure homogenization treatment, and stirring and mixing uniformly to obtain the pesticide preparation.

7. The method of claim 6, wherein, In the step S2, the high-pressure homogenization is performed by using a multi-channel micro-jet diamond alternating cavity device, the homogenization pressure is 22000-27000 psi, and the homogenization flow rate is 90-110 mL / min.

8. A method for controlling pests, the method comprising applying the anti-ultraviolet nano-pesticide preparation according to any one of claims 1-5.

9. Use of the anti-ultraviolet nano-pesticide preparation according to any one of claims 1-5 in controlling pests.

10. A light stabilizer for addition to a pesticide formulation to prevent photolysis of the pesticide, characterized in that, The light stabilizer is a combination of nano-titanium dioxide, hydrogenated rosin and epoxy soybean oil, and the mass ratio of the three is (2.8-4.5):(0.3-1.4):(4.3-9.0).

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