A multifunctional plant protection agent and its preparation method and application

Abstract

The present application relates to a kind of multifunctional plant protection agent and its preparation method and application.The multifunctional plant protection agent is composed of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, eucalyptus oil, tween 80 and water.The present application provides a kind of preparation method of multifunctional plant protection agent, comprising: dispersing eucalyptus oil in tween 80 aqueous solution to obtain eucalyptus oil dispersion liquid;Nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate and kaolin are mixed and then added to eucalyptus oil dispersion liquid to obtain multifunctional plant protection agent.The present application provides a kind of application of multifunctional plant protection agent in plant pest control.The multifunctional plant protection agent of the present application can not only kill pests, but also physically block pests, and can also repel pests, solve the problem of single function of existing plant protection agent, and the problem of strong resistance to chemical pesticides and easy to cause environmental pollution.

Description

TECHNICAL FIELD

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

[0002] In the process of agricultural production, the invasion of pests seriously affects the yield and quality of crops. Taking the citrus industry as an example, the citrus psyllid is the main transmission medium of citrus Huanglongbing, which causes devastating damage to citrus trees. Although the widespread use of chemical pesticides has controlled pests to some extent, long-term dependence has led to increased pest resistance, and pesticide runoff has caused pollution to the ecological environment such as soil and water. In addition, traditional control methods are single in function and cannot meet the comprehensive control needs of pests in green agriculture and sustainable development.

[0003] Nanomaterials have unique physical and chemical properties, and their application in the field of agriculture has gradually emerged. In the aspect of pesticide formulation improvement, nano-SiO2 can be used as a carrier to improve the stability, target adsorption and slow-release performance of pesticides. Although nano-SiO2 has shown potential advantages in the field of agriculture, there are still significant limitations in current research and application. Most existing research focuses on the exploration and application of single function of nano-SiO2, such as some research only focuses on its slow-release performance as a pesticide carrier, or simply explores its mechanism of action as a biological stimulant to induce plant resistance, lacking systematic exploration of multifunctional synergistic effects; from the perspective of control objects, most researches are limited to certain specific pests, and the complexity and diversity of pest occurrence in agricultural production are not fully considered. This single-function, single-object research mode has led to a serious lack of systematic exploration of the multifunctional synergistic effects of nano-SiO2.

[0004] Therefore, it is urgent to develop an efficient, safe and multifunctional new green plant protection agent and to construct a comprehensive control technical solution in the field of modern agricultural pest control. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a multifunctional plant protection agent and a preparation method and application thereof, to solve the problem of single function of existing plant protection agents, and also to solve the problems of strong resistance to existing chemical pesticides and easy environmental pollution.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A multifunctional plant protection agent is composed of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, eucalyptus oil, Tween 80 and water.

[0008] According to the above technical means, by taking nano-SiO2 as the main active ingredient, compounding sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and eucalyptus oil auxiliary agents, and synergistic effect, the multifunctional plant protection agent integrates the functions of killing, blocking and avoiding, can efficiently prevent and control citrus psylla and other pests, and significantly reduces the use of chemical pesticides. The environmental friendly characteristics help to protect the safety of agricultural products, reduce the risk of environmental pollution, and promote the development of green agriculture. The protection agent can construct a comprehensive and long-acting protection system for crops, effectively guarantee the stability and economic benefits of agricultural production, and provide important guarantee for sustainable agricultural development. The problems of single function of the existing plant protection agent are solved, and the problems of strong drug resistance and easy environmental pollution of the existing chemical pesticides are also solved.

[0009] Among them, the eucalyptus oil effectively enhances the toxic activity and avoidance effect of the multifunctional plant protection agent; the sodium butylnaphthalene sulfonate acts as a dispersing agent to make the nano-SiO2 uniformly distributed in the multifunctional plant protection agent; the sodium carboxymethyl starch improves the adhesion and spreading performance of the multifunctional plant protection agent on the plant surface; and the kaolin acts as a carrier to load the nano-SiO2.

[0010] Preferably, the nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and eucalyptus oil are 60g-80g:3g-7g:3g-7g:10g-30g:100-300mL in g:g:g:g:mL.

[0011] Preferably, the nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin and eucalyptus oil are 70g:5g:5g:20g:200mL in g:g:g:g:mL.

[0012] Preferably, the particle size of the nano-SiO2 is 15-25nm.

[0013] Preferably, the particle size of the nano-SiO2 is 18-22nm.

[0014] Preferably, the particle size of the nano-SiO2 is 20nm.

[0015] The application also provides a preparation method of the multifunctional plant protection agent, comprising the following steps:

[0016] The eucalyptus oil is dispersed in the Tween 80 aqueous solution to obtain a eucalyptus oil dispersion;

[0017] The nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate and kaolin are mixed to obtain a mixture;

[0018] The mixture is added into the eucalyptus oil dispersion to obtain the multifunctional plant protection agent.

[0019] 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.

[0020] Preferably, the mass percentage of Tween 80 in the Tween 80 aqueous solution is 0.1%.

[0021] 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.

[0022] 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.

[0023] By combining stirring and oscillating mixing, the initial wetting and sufficient dispersion of the mixture are effectively achieved.

[0024] 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.

[0025] Preferably, the plant pests are at least one of citrus pests, vegetable pests and litsea cubeba pests.

[0026] Preferably, the citrus pests are one or both of citrus psyllids and aphids.

[0027] Preferably, the vegetable pest is Spodoptera litura.

[0028] Preferably, the insect pest of Litsea cubeba is Meloidogyne meloidogy.

[0029] 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.

[0030] Preferably, the citrus psyllid is an adult citrus psyllid and / or a fifth-instar nymph of citrus psyllid.

[0031] Preferably, the Spodoptera litura is a 2nd instar nymph of Spodoptera litura.

[0032] Preferably, the application method of the multifunctional plant protection agent is that the multifunctional plant protection agent is sprayed on the plant infested by the plant pest.

[0033] Preferably, the multifunctional plant protection agent is sprayed on the healthy plant to form a preventive barrier to physically block the plant pest infestation and avoid the plant pest.

[0034] Preferably, for citrus pests, the application method of the multifunctional plant protection agent is that the multifunctional plant protection agent is sprayed on the plant infested by the citrus pest.

[0035] Preferably, for citrus pests, the application method of the multifunctional plant protection agent is that the multifunctional plant protection agent is sprayed on the healthy plant to form a preventive barrier to physically block the citrus pest infestation and avoid the citrus pest.

[0036] Preferably, for litsea cubeba pests, the application method of the multifunctional plant protection agent is that the multifunctional plant protection agent is sprayed on the plant infested by the litsea cubeba pest.

[0037] Preferably, for litsea cubeba pests, the application method of the multifunctional plant protection agent is that the multifunctional plant protection agent is sprayed on the healthy plant to form a preventive barrier to physically block the citrus pest infestation and avoid the citrus pest.

[0038] The application also provides a product for preventing and treating citrus pests, comprising the multifunctional plant protection agent.

[0039] Advantages of the application:

[0040] The multifunctional plant protection agent of the application has multiple functions of killing pests, physically blocking, and avoiding pests through the mutual synergistic effect of nano-SiO2, sodium carboxymethyl starch, sodium butylnaphthalene sulfonate, kaolin, and eucalyptus oil, and can achieve efficient and comprehensive prevention and control of citrus psylla. The multifunctional plant protection agent of the application not only fills the technical gap, reduces the use of chemical pesticides, alleviates environmental pollution and agricultural product safety problems, and promotes the green and sustainable development of agriculture, but also provides comprehensive and persistent protection for crops through the synergistic effect of multiple functions, ensures the stability and economic benefits of agricultural production, and meets the urgent needs of modern agricultural pest comprehensive prevention and control. At the same time, the broad-spectrum effect of the multifunctional plant protection agent on aphids, cotton bollworms, and other pests such as Japanese beetles is verified, which further proves the application potential of the multifunctional plant protection agent, provides new ideas and new solutions for pest control of multiple crops, and has application value in the field of agricultural plant protection technology. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Figure 2 is a post-mortem characterization diagram of citrus psylla 5th instar nymphs; wherein,Figure 1 A 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;

[0042] Figure 2 This is a model diagram of the device for evaluating the barrier effect of citrus psyllid adults;

[0043] Figure 3 To evaluate the barrier effect of nano-SiO2 multifunctional plant protection agent on citrus psyllids;

[0044] Figure 4 Schematic diagram of the experiment of spraying potted seedlings with adult citrus psyllids;

[0045] Figure 5 This is a photo of Murraya aromatica sprayed with nano-SiO2 multifunctional plant protection agent one day after application;

[0046] Figure 6 To evaluate the repellent effect of nano-SiO2 multifunctional plant protection agent on citrus psyllid. DETAILED DESCRIPTION

[0047] 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.

[0048] 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.

[0049] The sources of reagents and materials used in the following examples are as follows:

[0050] 1. Test reagents

[0051] Nano-SiO2 (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., particle size about 20 nm); sodium carboxymethyl starch (purchased from Shanghai Macklin Biochemical Technology Co., Ltd.), sodium butyl naphthalene sulfonate (purchased from Shanghai Macklin Biochemical Technology Co., Ltd.), kaolin (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.), tea tree oil (purchased from Jiangxi Cedrus Natural Medicinal Oil Co., Ltd.), Tween 80 (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) and water (taken from the laboratory pure water).

[0052] 2. Test insects

[0053] The citrus psylla and aphids were collected from the plants of Chamaecyparis funebris on the campus of South China Agricultural University, and were further bred on the plants of Chamaecyparis funebris in the insect breeding room of the Engineering Research Center of Biological Control of the Ministry of Education, South China Agricultural University. The temperature was controlled at 26±1℃, the relative humidity was 60%±5%, and the light cycle was 14L:10D. The Japanese beetle was collected from the plants of C. funebris in Lianshan Zhuang and Yao Autonomous County, Qingyuan, and was bred in the Engineering Research Center of Biological Control of the Ministry of Education, South China Agricultural University. The breeding conditions were temperature 26±1℃, relative humidity 60%±5%, and light cycle 14L:10D. The Helicoverpa armigera population was purchased from Henan Jiyuan Baiyun Industry Co., Ltd., and was further bred in the Engineering Research Center of Biological Control of the Ministry of Education, South China Agricultural University. The breeding conditions were controlled temperature 25±2℃, relative humidity 65%±2%, and light cycle 14L:10D.

[0054] Example 1

[0055] A method for preparing a multifunctional plant protection agent, comprising the following steps:

[0056] S1, preparing a Tween 80 aqueous solution with a mass percentage content of Tween 80 of 0.1%;

[0057] S2, dispersing 2mL of tea tree oil stock solution in 18mL of Tween 80 aqueous solution prepared in S1 to obtain 20mL of tea tree oil dispersion;

[0058] S3, mixing 0.7g of nano-SiO2, 0.05g of sodium carboxymethyl starch, 0.05g of sodium butyl naphthalene sulfonate and 0.2g of kaolin, and oscillating to mix into a uniform powder mixture;

[0059] S4, under continuous stirring, slowly adding the mixture in S3 into the tea tree oil dispersion prepared in S2, alternately stirring (initial wetting) and oscillating (sufficient dispersion) while adding, until all is added and mixed uniformly, to obtain a multifunctional plant protection agent.

[0060] Example 2

[0061] A method for preparing a multifunctional plant protection agent, comprising the following steps:

[0062] S1, prepare a 0.1% Tween 80 aqueous solution;

[0063] S2, disperse 0.2 mL of the tea tree oil stock solution in 19.8 mL of the Tween 80 aqueous solution prepared in S1 to obtain 20 mL of a tea tree oil dispersion;

[0064] S3, mix 0.7 g of nano-SiO2, 0.05 g of sodium carboxymethyl starch, 0.05 g of sodium butylnaphthalene sulfonate, and 0.2 g of kaolin, and shake to mix into a uniform powder mixture;

[0065] S4, under continuous stirring, slowly add the mixture in S3 to the tea tree oil dispersion prepared in S2, alternately stirring (preliminary wetting) and shaking (sufficient dispersion) until all is added and mixed evenly to obtain a multifunctional plant protection agent.

[0066] Example 3

[0067] A method for preparing a multifunctional plant protection agent, comprising the following steps:

[0068] S1, prepare a 0.1% Tween 80 aqueous solution;

[0069] S2, disperse 2 mL of the tea tree oil stock solution in 18 mL of the Tween 80 aqueous solution prepared in S1 to obtain 20 mL of a tea tree oil dispersion;

[0070] S3, mix 0.6 g of nano-SiO2, 0.07 g of sodium carboxymethyl starch, 0.07 g of sodium butylnaphthalene sulfonate, and 0.26 g of kaolin, and shake to mix into a uniform powder mixture;

[0071] S4, under continuous stirring, slowly add the mixture in S3 to the tea tree oil dispersion prepared in S2, alternately stirring (preliminary wetting) and shaking (sufficient dispersion) until all is added and mixed evenly to obtain a multifunctional plant protection agent.

[0072] Example 4

[0073] A method for using the multifunctional plant protection agent prepared in Example 1 to kill citrus psylla adult insects and 5th instar nymphs, comprising the following steps:

[0074] First, place 20 citrus psylla test insects (adults or 5th instar nymphs) in a culture dish;

[0075] Subsequently, insert a branch with leaves of about 8 cm long into a 2 mL centrifuge tube (tube cover is cut off and sealed with sealing film) fixed at the bottom with Play-Doh, and place the whole into an aviation cup.

[0076] 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.

[0077] Among them, mortality rate (%) = (number of dead insects ÷ total number of insects) × 100;

[0078] Adjusted mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100.

[0079] Table 1 shows the adjusted mortality rates of citrus psyllid adults and fifth-instar nymphs at different times

[0080]

[0081] 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.

[0082] 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.

[0083] Example 5

[0084] A method for using the multifunctional plant protection agent prepared in Example 1 to block adult citrus psyllids comprises the following steps:

[0085] 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.

[0086] 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.

[0087] Among them, the insect attraction rate (%) = (number of insects on each plant ÷ total number of insects) × 100.

[0088] 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.

[0089] Example 6

[0090] A method for controlling citrus psyllid adults using the multifunctional plant protection agent prepared in Example 1 comprises the following steps:

[0091] like Figure 4 As 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.

[0092] Where, insect population reduction rate (%) = (number of live insects before treatment - number of live insects after treatment) / number of live insects before treatment × 100;

[0093] 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.

[0094] Table 2 shows the control effect of multifunctional plant protection agents on citrus psyllid adults

[0095]

[0096] 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.

[0097] Example 7

[0098] A method for spraying the multifunctional plant protection agent prepared in Example 1 on plants to reduce pest damage comprises the following steps:

[0099] 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.

[0100] 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.

[0101] Example 8

[0102] 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:

[0103] 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.

[0104] Among them, mortality rate (%) = (number of dead insects ÷ total number of insects) × 100;

[0105] Adjusted mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100.

[0106] Table 3 shows the corrected mortality rates of three pests: aphids, second-instar nymphs of Spodoptera litura and Meloidae at different times

[0107]

[0108] 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.

[0109] Example 9

[0110] A method for spraying the multifunctional plant protection agent prepared in Example 1 on plants to repel pests comprises the following steps:

[0111] 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.

[0112] 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.

[0113] 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.

[0114] In summary, the multifunctional plant protection agent of the present application has the multiple functions of "insect killing + physical blocking + avoiding". Through the bioassay experiment of the adult and 5th instar nymph of citrus psylla, the blocking effect experiment in the seedling cage and the spraying experiment in the indoor seedling pot, it is verified that the multifunctional plant protection agent has significant control effect on citrus psylla, and also has good toxic killing activity on aphids, 2nd instar larvae of Prodenia litura and meloidae pests. The development of the multifunctional plant protection agent provides a new scheme for green prevention and control of agricultural pests, and the preparation method is simple, and the application range is wide.

[0115] The multifunctional plant protection agent has excellent broad-spectrum and high-efficiency properties, which provides a wide application prospect. Not only can it greatly reduce the use of chemical pesticides, reduce environmental pollution and pesticide residue risk, and protect the quality and safety of agricultural products, but also can provide rapid, comprehensive and long-acting protection for crops, thereby improving the stability and economic benefits of agricultural production, and effectively promoting the development of green agriculture. In the field of agricultural plant protection technology, it has the value of popularization and application.

[0116] The above examples are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. The equivalent replacement or transformation made by the person skilled in the art on the basis of the present application is within the protection scope of the present application.

Claims

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

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

3. A method for preparing the multifunctional plant protection agent according to claim 1 or claim 2, 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.

4. The method for preparing the multifunctional plant protection agent according to claim 3, 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.

5. Use of a multifunctional plant protection agent prepared by the preparation method according to claim 3 or claim 4 in plant pest control, characterized in that: The plant pest control is at least one of the following; Repel, block or poison citrus psyllids; Poison to kill aphids, armyworms or medlars.

6. The use according to claim 5, characterized in that The citrus psyllid is an adult citrus psyllid or a fifth-instar nymph of citrus psyllid; Alternatively, the Spodoptera litura is a second-instar nymph of Spodoptera litura.

7. The use according to claim 5, 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.

8. A product for controlling citrus pests, characterized in that: The method comprises the multifunctional plant protection agent according to claim 1 or claim 2.

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