Multifunctional plant protective agent as well as preparation method and application thereof

Abstract

The invention relates to a multifunctional plant protective agent as well as a preparation method and application thereof. The multifunctional plant protective agent is prepared from nano SiO2, sodium carboxymethyl starch, sodium butyl naphthalene sulfonate, kaolin, Australian tea tree essential oil, Tween 80 and water. The invention provides a preparation method of a multifunctional plant protective agent, which comprises the following steps: dispersing Australian tea tree essential oil in a Tween 80 aqueous solution to obtain Australian tea tree essential oil dispersion liquid; and mixing nano SiO2, sodium carboxymethyl starch, sodium butyl naphthalene sulfonate and kaolin, and adding the mixture into the Australian tea tree essential oil dispersion liquid to obtain the multifunctional plant protective agent. The invention provides application of a multifunctional plant protective agent in plant pest control. The multifunctional plant protective agent disclosed by the invention not only can kill pests, but also can physically block the pests and repel the pests, and solves the problems that the existing plant protective agent is single in function, and the existing chemical pesticide is strong in drug resistance and easy to cause environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural plant protection, and in particular to a multifunctional plant protection agent, a preparation method and application thereof. Background Art

[0002] In agricultural production, pests and diseases severely impact crop yield and quality. For example, in the citrus industry, the citrus psyllid, the primary vector of citrus Huanglongbing (Huanglongbing) disease, wreaks havoc on citrus trees. While widespread use of chemical pesticides has somewhat controlled pests and diseases, long-term reliance on them has led to increased pest resistance, and pesticide runoff has polluted soil, water, and other ecological environments. Furthermore, traditional pest control methods are limited in scope and fail to meet the comprehensive pest and disease control needs of green agriculture and sustainable development.

[0003] Due to their unique physical and chemical properties, the application research of nanomaterials in the agricultural field is gradually emerging. In terms of pesticide formulation improvement, nano-SiO2 can be used as a carrier to enhance the stability, target adsorption and slow-release performance of pesticides. Although nano-SiO2 has shown potential advantages in the agricultural field, current research and application still have significant limitations. Most existing results focus on the exploration and application of the single function of nano-SiO2. For example, some studies only focus on its slow-release performance as a pesticide carrier, or simply explore its mechanism of action as a biostimulant to induce plant resistance, lacking a systematic exploration of multifunctional synergistic effects; from the perspective of prevention and control targets, most studies are limited to targeting a specific type of pests and diseases, and fail to fully consider the complexity and diversity of pests and diseases in agricultural production. This single-function, single-object research model has led to a serious lack of systematic exploration of the multifunctional synergistic effects of nano-SiO2.

[0004] In view of this, developing a new type of efficient, safe and multifunctional green plant protectant and building a comprehensive prevention and control technology plan have become key issues that need to be urgently addressed in the field of modern agricultural pest control. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a multifunctional plant protection agent and its preparation method and application, so as to solve the problem of single function of existing plant protection agents, and also solve the problem of strong drug resistance and easy environmental pollution of existing chemical pesticides.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A multifunctional plant protection agent is composed of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, Australian tea tree essential oil, Tween 80 and water.

[0007] Based on the above technical approach, by using nano-SiO2 as the main active ingredient and compounding sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, and Australian tea tree essential oil as adjuvants, the synergistic effects of these ingredients create a multifunctional plant protectant that combines insecticide, barrier, and repellent functions. It effectively controls pests such as citrus psyllids while significantly reducing the use of chemical pesticides. Its environmentally friendly properties help ensure the safety of agricultural products, reduce environmental pollution risks, and promote the development of green agriculture. This protectant can establish a comprehensive, long-term protection system for crops, effectively ensuring the stability and economic benefits of agricultural production, and providing important support for sustainable agricultural development. This effectively addresses the single-function problem of existing plant protectants, as well as the strong resistance and environmental pollution problems of existing chemical pesticides.

[0008] Among them, Australian tea tree essential oil effectively enhances the toxic activity and repellent effect of the multifunctional plant protection agent; sodium butylnaphthalenesulfonate is used as a dispersant to evenly distribute nano-SiO2 in the multifunctional plant protection agent; sodium carboxymethyl starch improves the adhesion and spreading performance of the multifunctional plant protection agent on the plant surface; kaolin is used as a carrier to load nano-SiO2.

[0009] Preferably, the nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and Australian tea tree essential oil are calculated in g:g:g:g:mL in the proportion of 60g~80g:3g~7g:3g~7g:10g~30g:100~300mL.

[0010] Preferably, the nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and Australian tea tree essential oil are calculated in the ratio of g:g:g:g:mL to be 70g:5g:5g:20g:200mL.

[0011] Preferably, the particle size of the nano-SiO2 is 15-25 nm.

[0012] Preferably, the particle size of the nano-SiO2 is 18-22 nm.

[0013] Preferably, the particle size of the nano-SiO2 is 20 nm.

[0014] The present invention also provides a method for preparing the multifunctional plant protection agent according to the present invention, comprising the following steps: Dispersing Australian tea tree essential oil in a Tween 80 aqueous solution to obtain an Australian tea tree essential oil dispersion; Mixing nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate and kaolin to obtain a mixture; The mixture is added into an Australian tea tree essential oil dispersion to obtain a multifunctional plant protection agent.

[0015] The present invention's method for preparing a multifunctional plant protectant involves diluting Australian tea tree essential oil and then directly mixing it with nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, and kaolin to produce the multifunctional plant protectant. This method offers the advantages of a simple preparation method, mild conditions, and a wide range of raw material sources. The risk of environmental pollution during both the preparation process and after application is low, effectively addressing the issues of strong pesticide resistance and environmental pollution associated with existing chemical pesticides.

[0016] Preferably, the mass percentage of Tween 80 in the Tween 80 aqueous solution is 0.1%. By diluting the Australian tea tree essential oil with a Tween 80 aqueous solution, the dispersibility of the Australian tea tree essential oil was effectively improved.

[0017] Preferably, the mixture is added to a dispersion of Australian tea tree essential oil, and the mixture is mixed by stirring and oscillating at normal temperature and pressure to obtain the multifunctional plant protection agent.

[0018] By combining stirring and oscillating mixing, the initial wetting and sufficient dispersion of the mixture are effectively achieved.

[0019] The present invention also provides an application of the multifunctional plant protection agent prepared by the preparation method of the present invention in plant pest control.

[0020] Preferably, the plant pests are at least one of citrus pests, vegetable pests and litsea cubeba pests.

[0021] Preferably, the citrus pests are one or both of citrus psyllids and aphids.

[0022] Preferably, the vegetable pest is Spodoptera litura.

[0023] Preferably, the insect pest of Litsea cubeba is Meloidogyne raphaniansis.

[0024] The multifunctional plant protectant's mechanism of action against plant pests is as follows: Nano-SiO2, the primary active ingredient, absorbs onto the insect's body wall, destroying its cuticular wax layer. Combined with the neurotoxic effects of Australian tea tree essential oil, this highly effective agent kills target pests. After spraying, the protectant forms a physical barrier on the plant surface, physically blocking contact between citrus psyllids, aphids, Spodoptera litura, and Meloidae, significantly reducing their feeding and egg-laying behavior. Furthermore, the scent of Australian tea tree essential oil acts as a pest repellent, further reducing the risk of infestation.

[0025] Preferably, the citrus psyllid is an adult citrus psyllid and / or a fifth-instar nymph of citrus psyllid.

[0026] Preferably, the Spodoptera litura is a 2nd instar nymph of Spodoptera litura.

[0027] Preferably, the multifunctional plant protection agent is applied by spraying the multifunctional plant protection agent on plants infected by plant pests.

[0028] Preferably, the multifunctional plant protection agent is sprayed on healthy plants to form a preventive barrier to physically block plant pest infestation and repel plant pests.

[0029] Preferably, for citrus pests, the method of applying the multifunctional plant protection agent is: spraying the multifunctional plant protection agent on plants infected by citrus pests.

[0030] Preferably, for citrus pests, the application method of the multifunctional plant protection agent is: spraying the multifunctional plant protection agent on healthy plants to form a preventive barrier, thereby physically blocking the infestation of citrus pests and repelling citrus pests.

[0031] Preferably, for litsea cubeba pests, the method of applying the multifunctional plant protection agent is: spraying the multifunctional plant protection agent on plants infected by litsea cubeba pests.

[0032] Preferably, for Litsea cubeba pests, the application method of the multifunctional plant protection agent is: spraying the multifunctional plant protection agent on healthy plants to form a preventive barrier, thereby physically blocking the infestation of citrus pests and repelling citrus pests.

[0033] The present invention also provides a product for preventing and controlling citrus pests, comprising the multifunctional plant protection agent of the present invention.

[0034] Beneficial effects of the present invention: The multifunctional plant protection agent of the present invention has multiple functions of insecticide, physical barrier and repellency through the synergistic effect of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and Australian tea tree essential oil, and can achieve efficient and comprehensive prevention and control of citrus psyllids. The multifunctional plant protection agent of the present invention can not only fill the technical gap, reduce the use of chemical pesticides, alleviate environmental pollution and agricultural product safety issues, and promote the green and sustainable development of agriculture, but also provide comprehensive and lasting protection for crops through the synergistic effect of multiple functions, ensure the stability and economic benefits of agricultural production, and meet the urgent needs of modern agricultural integrated pest control. At the same time, its broad-spectrum effect on other pests such as aphids, Spodoptera litura and Meloidae has been verified, further proving its application potential, providing new ideas and new solutions for the pest control of various crops, and has promotion and application value in the field of agricultural plant protection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a picture of the 5th instar nymph of the citrus psyllid after death; Figure 1A in the figure is a multifunctional plant protection agent nano-SiO2 used to treat the back of the fifth-instar nymph of the citrus psyllid. Figure 1 B in the figure is the ventral surface of the fifth-instar nymph of citrus psyllid treated with nano-SiO2 multifunctional plant protection agent; Figure 2 This is a model diagram of the device for evaluating the barrier effect of citrus psyllid adults; Figure 3 To evaluate the barrier effect of nano-SiO2 multifunctional plant protection agent on citrus psyllids; Figure 4 Schematic diagram of the experiment of spraying potted seedlings with adult citrus psyllids; Figure 5 This is a photo of Murraya aromatica sprayed with nano-SiO2 multifunctional plant protection agent one day after application; Figure 6 To evaluate the repellent effect of nano-SiO2 multifunctional plant protection agent on citrus psyllid. DETAILED DESCRIPTION

[0036] The following will describe the embodiments of the present invention with reference to preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0037] If no specific techniques or conditions are specified in the specific examples, the techniques or conditions described in the literature in this field or the product instructions were used. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional products.

[0038] The sources of reagents and materials used in the following examples are as follows: 1. Test reagents Nano-SiO2 (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., particle size about 20 nm); sodium carboxymethyl starch (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), sodium butylnaphthalenesulfonate (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), kaolin (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.), Australian tea tree essential oil (purchased from Jiangxi Xuesong Natural Medicinal Oil Co., Ltd.), Tween 80 (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) and water (pure water from the laboratory).

[0039] 2. Test insects Citrus psyllids and aphids were collected from Murraya odora plants on the campus of South China Agricultural University and subcultured on Murraya odora plants in the insectary at the Ministry of Education Engineering Research Center for Biological Control at South China Agricultural University. The insectary was maintained at a temperature of 26±1°C, a relative humidity of 60%±5%, and a photoperiod of 14 L:10 D. Meloidogyne spp. were collected from Litsea cubeba plants in Lianshan Zhuang and Yao Autonomous County, Qingyuan City, and reared at the Ministry of Education Engineering Research Center for Biological Control at South China Agricultural University. Rearing conditions were 26±1°C, 60%±5% relative humidity, and a photoperiod of 14 L:10 D. Spodoptera litura stocks were purchased from Baiyun Industrial Co., Ltd. in Jiyuan, Henan Province, and subcultured at the Ministry of Education Engineering Research Center for Biological Control at South China Agricultural University. Rearing conditions were 25±2°C, 65%±2% relative humidity, and a photoperiod of 14 L:10 D.

[0040] Example 1 A method for preparing a multifunctional plant protection agent comprises the following steps: S1. Prepare a Tween 80 aqueous solution with a mass percentage of 0.1% Tween 80; S2, dispersing 2 mL of Australian tea tree essential oil mother liquor in 18 mL of Tween 80 aqueous solution prepared in S1 to obtain 20 mL of Australian tea tree essential oil dispersion; S3, 0.7g of nano-SiO2, 0.05g of sodium carboxymethyl starch, 0.05g of sodium butylnaphthalene sulfonate and 0.2g of kaolin were mixed and shaken to form a uniform powder mixture; S4. Under continuous stirring, slowly add the mixture in S3 to the Australian tea tree essential oil dispersion prepared in S2, stirring (preliminary wetting) and shaking (fully dispersing) alternately while adding until all the mixture is added and evenly mixed to obtain a multifunctional plant protection agent.

[0041] Example 2 A method for preparing a multifunctional plant protection agent comprises the following steps: S1. Prepare a Tween 80 aqueous solution with a mass percentage of 0.1% Tween 80; S2, dispersing 0.2 mL of Australian tea tree essential oil mother liquor in 19.8 mL of Tween 80 aqueous solution prepared in S1 to obtain 20 mL of Australian tea tree essential oil dispersion; S3, 0.7g of nano-SiO2, 0.05g of sodium carboxymethyl starch, 0.05g of sodium butylnaphthalene sulfonate and 0.2g of kaolin were mixed and shaken to form a uniform powder mixture; S4. Under continuous stirring, slowly add the mixture in S3 to the Australian tea tree essential oil dispersion prepared in S2, stirring (preliminary wetting) and shaking (fully dispersing) alternately while adding until all the mixture is added and evenly mixed to obtain a multifunctional plant protection agent.

[0042] Example 3 A method for preparing a multifunctional plant protection agent comprises the following steps: S1. Prepare a Tween 80 aqueous solution with a mass percentage of 0.1% Tween 80; S2, dispersing 2 mL of Australian tea tree essential oil mother liquor in 18 mL of Tween 80 aqueous solution prepared in S1 to obtain 20 mL of Australian tea tree essential oil dispersion; S3, 0.6g of nano-SiO2, 0.07g of sodium carboxymethyl starch, 0.07g of sodium butylnaphthalene sulfonate and 0.26g of kaolin were mixed and shaken to form a uniform powder mixture; S4. Under continuous stirring, slowly add the mixture in S3 to the Australian tea tree essential oil dispersion prepared in S2, stirring (preliminary wetting) and shaking (fully dispersing) alternately while adding until all the mixture is added and evenly mixed to obtain a multifunctional plant protection agent.

[0043] Example 4 A method for using the multifunctional plant protection agent prepared in Example 1 to kill citrus psyllid adults and fifth-instar nymphs comprises the following steps: First, 20 citrus psyllid test insects (adults or 5th-instar nymphs) were placed in a petri dish; Then, insert an approximately 8 cm long branch with Murraya aromatica leaves into a 2 mL centrifuge tube fixed at the bottom with plasticine (the tube cap was cut off and sealed with parafilm), and place the entire tube into an aviation cup; Subsequently, the citrus psyllid test insects were immersed in the multifunctional plant protection agent (treatment group) and clean water (control group) prepared in Example 1 for 10 seconds, taken out and transferred to the branches in the aviation cup, sealed with a mesh bag, and placed in an artificial climate chamber for cultivation. Three repetitions were set for each treatment group and control group. The number of dead insects was recorded 24h, 48h, and 72h after treatment (judgment standard: no reaction when the insect body was lightly touched), and the mortality rate and corrected mortality rate were calculated. In addition, the dead citrus psyllid test insects at each time point (24h, 48h, 72h) were collected, and their morphological characteristics after death were observed using an optical microscope. The results are shown in Table 1 and Figure 1 shown.

[0044] Among them, mortality rate (%) = (number of dead insects ÷ total number of insects) × 100; Adjusted mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100.

[0045] Table 1 shows the adjusted mortality rates of citrus psyllid adults and fifth-instar nymphs at different times From the comparative analysis in Table 1, it can be seen that after treatment with the nano-SiO2 multifunctional plant protection agent prepared in Example 1, the corrected mortality rates of citrus psyllid adults and 5th instar nymphs reached 100% at 24 h, fully demonstrating that the multifunctional plant protection agent of the present invention has extremely high toxicity and significant fast-acting properties.

[0046] from Figure 1 The analysis showed that the internodes and wings of the fifth-instar nymphs of the citrus psyllid treated with the multifunctional plant protection agent of the present invention were mostly covered with white powder of the protection agent, which proved that the multifunctional plant protection agent of the present invention had good adhesion.

[0047] Example 5 A method for using the multifunctional plant protection agent prepared in Example 1 to block adult citrus psyllids comprises the following steps: like Figure 2 As shown, the experiment was carried out in an insect cage: Murraya odorifera seedlings were pre-screened for being free of citrus psyllids, three plants on the left were sprayed with water (control group), and three plants on the right were sprayed with the nano-SiO2 multifunctional plant protection agent prepared in Example 1 (treatment group). Figure 2 The cylindrical device in the middle is used to hold 100 adult citrus psyllids.

[0048] Subsequently, 100 citrus psyllid adults were released from the cylindrical device into the insect cage. The number of adults attached to the plants in the control group and the treated group was recorded and counted at 1 hour, 1, 2, 3, 5, and 7 days after treatment. The experiment was repeated three times, and the data were statistically analyzed. The results are as follows: Figure 3 shown.

[0049] Among them, the insect attraction rate (%) = (number of insects on each plant ÷ total number of insects) × 100.

[0050] from Figure 3 Analysis revealed that from one hour to seven days after spraying the nano-SiO2 multifunctional plant protectant prepared in Example 1, the insect attraction rate in the treated group was consistently significantly lower than that in the control group, with the difference reaching a highly significant level, indicating that the multifunctional plant protectant of the present invention has a significant barrier effect on citrus psyllid adults. Just one hour after treatment, the distribution of citrus psyllid adults on seedlings in the treated group versus the control group showed significant differences. This barrier effect stabilized after one day and persisted for seven days after treatment. These results demonstrate that the multifunctional plant protectant of the present invention not only has a rapid onset of action but also a long-lasting effect.

[0051] Example 6 A method for controlling citrus psyllid adults using the multifunctional plant protection agent prepared in Example 1 comprises the following steps: like Figure 4As shown, the experiment used clean water as a control group and the multifunctional plant protectant prepared in Example 1 as a treatment group. Each group contained three Murraya Osmanthus fragrans seedlings that had been pre-screened to be free of citrus psyllids. 100 adult citrus psyllids were placed on each seedling. After stabilization, the leaves were evenly sprayed with either clean water or the multifunctional plant protectant prepared in Example 1 until the leaves were moist and drip-free. The number of surviving adults (insect population) on plants in each treatment group was counted on days 1, 3, 5, and 7 after treatment. The population reduction rate and relative control efficacy were calculated from this data. The results are shown in Table 2.

[0052] Where, insect population reduction rate (%) = (number of live insects before treatment - number of live insects after treatment) / number of live insects before treatment × 100; Control effect (%) = (insect population reduction rate in the treatment area - insect population reduction rate in the control group) / (1 - insect population reduction rate in the control group) × 100.

[0053] Table 2 shows the control effect of multifunctional plant protection agents on citrus psyllid adults As shown in Table 2, the multifunctional plant protection agent prepared in Example 1 demonstrated significant control effectiveness against citrus psyllids. One day after spraying, the population reduction rate and relative control efficacy reached 98% ± 1% and 97.9% ± 0.7%, respectively. This remained relatively stable for seven days, with the population reduction rate and relative control efficacy reaching 99.3% ± 1.2% and 99.3% ± 0.9%, respectively, at that time. This demonstrates the multifunctional plant protection agent's excellent sustained control capabilities, effectively controlling citrus psyllid populations over an extended period.

[0054] Example 7 A method for spraying the multifunctional plant protection agent prepared in Example 1 on plants to reduce pest damage comprises the following steps: The multifunctional plant protection agent prepared in Example 1 was evenly sprayed on the Murraya aromatica plants, and the growth status of the Murraya aromatica plants was observed 1, 2, and 3 days after the spraying. Figure 5 shown.

[0055] from Figure 5 Analysis shows that after spraying the multifunctional plant protectant of the present invention on Murraya osmanthus leaves, a uniform white coating forms, demonstrating good adhesion and spreadability on the leaf surface. This coating acts as a physical barrier, preventing pests from contacting the leaves, thereby reducing pest damage to the plants.

[0056] Example 8 A method for using the multifunctional plant protection agent prepared in Example 1 to kill three pests: citrus aphids, second-instar nymphs of Spodoptera litura, and Litsea cubeba pest (Meadowbrook spp.), using a unified insect immersion method to conduct a toxicity determination experiment. The specific operation is as follows: Twenty citrus aphids were selected and placed in a petri dish along with Murraya odora leaves approximately 8 cm long, wrapped at the base with wet cotton. Twenty second-instar nymphs of the citrus armyworm (Spodoptera litura) and 15 litsea cubeba (Coleoptera littoralis) were selected and placed in a petri dish and a lunch box, respectively. Each group of test insects was immersed in the multifunctional plant protection agent prepared in Example 1 (treatment group) or water (control group) for 10 seconds. The citrus aphid group was then supplemented with Murraya odora leaves, the citrus armyworm group with a feed of uniform size, and the litsea cubeba (Coleoptera littoralis) group with an equal amount of litsea cubeba leaves. All samples were cultured in an artificial climate chamber, with three biological replicates for each treatment. The number of dead insects was recorded 24, 48, and 72 hours after treatment (criterion: no reaction to lightly touching the insect body), and the mortality rate and adjusted mortality rate were calculated. The results are shown in Table 3.

[0057] Among them, mortality rate (%) = (number of dead insects ÷ total number of insects) × 100; Adjusted mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100.

[0058] Table 3 shows the corrected mortality rates of three pests: aphids, second-instar nymphs of Spodoptera litura and Meloidae at different times Analysis in Table 3 demonstrates that the multifunctional plant protection agent prepared in Example 1 exhibits significant broad-spectrum efficacy against citrus aphids, second-instar nymphs of citrus moth, and litsea cubeba pests (Melodes meloides). The 24-hour mortality rate against citrus aphids and second-instar nymphs of citrus moth, and the 48-hour mortality rate against litsea cubeba pests (Melodes meloides), reached 100%. During the experiment, it was found that even those litsea cubeba pests that survived 24 hours of treatment showed a significant decline in activity, essentially losing their ability to harm crops.

[0059] Example 9 A method for spraying the multifunctional plant protection agent prepared in Example 1 on plants to repel pests comprises the following steps: Each group contains 2 Murraya osmanthus seedlings that have been pre-screened and confirmed to be free of citrus psyllids. The 2 Murraya osmanthus seedlings in each group are placed in independent insect cages. 50 citrus psyllid adults are then placed on each seedling. After they stabilize, one group is evenly sprayed with clean water until the leaves are moist and not dripping, serving as the control group. The other group is evenly sprayed with the multifunctional plant protection agent prepared in Example 1 until the leaves are moist and not dripping, serving as the treatment group. The experiment is repeated 3 times. The number of adults on the plants is counted at 5 minutes, 10 minutes, 30 minutes, 1 hour, and 3 hours after treatment, and the repellent effect of the protective agent on citrus psyllids is calculated according to the following formula. The results are shown in the figure below. Figure 6 shown.

[0060] Avoidance rate (%) = [(C-T)÷C]×100, C is the number of adults in the control group, and T is the number of adults in the treatment group.

[0061] from Figure 6 Analysis revealed that the multifunctional plant protectant of the present invention exhibited a rapid repellent effect against citrus psyllids, reaching a repellent rate of 83.33% ± 1.15% just 5 minutes after spraying. The repellent rate then stabilized at 86.67% ± 1.15% over the next 10 minutes to 3 hours. This demonstrates that the multifunctional plant protectant not only exhibits a significant repellent effect but also exhibits a long-lasting and stable effect.

[0062] In summary, the multifunctional plant protection agent of the present invention has multiple functions of "insecticide + physical barrier + repellent". Through bioassay experiments on citrus psyllid adults and 5th-instar nymphs, as well as barrier effect experiments in seedling cages and spraying experiments on indoor seedling pots, it was verified that it has a significant control effect on citrus psyllids. At the same time, it also has good toxic activity against aphids, 2nd-instar larvae of Spodoptera litura, and medlar pests. The development of the multifunctional protective agent of the present invention provides a new solution for the green prevention and control of agricultural pests, and the preparation method is simple and has a wide range of applications.

[0063] The multifunctional plant protection agent of this invention possesses broad-spectrum and high-efficiency properties, endowing it with broad application prospects. It can not only significantly reduce the use of chemical pesticides, mitigate environmental pollution and the risk of pesticide residues, and ensure the quality and safety of agricultural products, but also provide rapid, comprehensive, and long-lasting protection for crops, thereby improving the stability and economic benefits of agricultural production and effectively promoting the development of green agriculture. It has great potential for widespread application in the field of agricultural plant protection technology.

[0064] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A multifunctional plant protection agent, characterized in that It is composed of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, Australian tea tree essential oil, Tween 80 and water.

2. The multifunctional plant protection agent according to claim 1, characterized in that The nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and Australian tea tree essential oil are calculated in terms of g:g:g:g:mL, which is 60g-80g:3g-7g:3g-7g:10g-30g:100-300mL.

3. The multifunctional plant protection agent according to claim 1, characterized in that The particle size of the nano-SiO2 is 15-25 nm.

4. A method for preparing the multifunctional plant protection agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: Dispersing Australian tea tree essential oil in a Tween 80 aqueous solution to obtain an Australian tea tree essential oil dispersion; Mixing nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate and kaolin to obtain a mixture; The mixture is added into an Australian tea tree essential oil dispersion to obtain a multifunctional plant protection agent.

5. The method for preparing the multifunctional plant protection agent according to claim 4, characterized in that: The mass percentage of Tween 80 in the Tween 80 aqueous solution is 0.1%; And / or, the mixture is added to an Australian tea tree essential oil dispersion, and the mixture is mixed by stirring and oscillating at normal temperature and pressure to obtain the multifunctional plant protection agent.

6. Use of the multifunctional plant protection agent prepared by the preparation method according to claim 4 or claim 5 in plant pest control.

7. The use according to claim 6, characterized in that The plant pests are at least one of citrus pests, vegetable pests and litsea cubeba pests; The citrus insect pests are one or both of citrus psyllids and aphids; The vegetable pest is Spodoptera litura; The insect pest of Litsea cubeba is Melia azedarach.

8. The use according to claim 7, characterized in that The citrus psyllid is an adult citrus psyllid and / or a fifth-instar nymph of citrus psyllid; And / or, the Spodoptera litura is a 2nd instar nymph of Spodoptera litura.

9. The use according to claim 7, characterized in that The method for applying the multifunctional plant protection agent is as follows: spraying the multifunctional plant protection agent on plants infected by plant pests; Alternatively, the multifunctional plant protection agent is sprayed on healthy plants to form a preventive barrier to physically block plant pests from infesting and repel plant pests.

10. A product for controlling citrus pests, characterized in that: The multifunctional plant protection agent according to any one of claims 1 to 3.

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