Composition, application, plant protective agent and preparation method of plant protective agent

Abstract

The invention discloses a composition, application, a plant protective agent and a preparation method of the plant protective agent, and relates to the technical field of plant protection, and the weight ratio of A to B is (30-60): (40-70). Wherein the component A is prepared from 97.80 to 99.45 percent of kaolin, 0.5 to 2.0 percent of tea saponin and 0.05 to 0.2 percent of a de-foaming agent; the component B is prepared from 0.01 to 0.4 percent of high acyl gellan gum and 99.6 to 99.99 percent of deionized water. Kaolin, a high-acyl gellan gum aqueous solution, tea saponin and a defoaming agent are combined according to a specific ratio to prepare the plant protective agent, so that the problems that an existing plant protective agent is poor in rain wash resistance, low in film forming property, serious in fruit surface adhesion in the harvesting period, difficult to clean and the like are solved, the prevention and treatment effect on diseases and insect pests is improved, meanwhile, the yield of agricultural products is increased, and the economic benefit is increased. The commodity value is improved, the price is low, and the use is convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of plant protection, and more specifically to a composition, application, plant protection agent and a preparation method thereof. Background Art

[0002] The occurrence of small pests such as thrips, whiteflies, aphids, and diseases such as downy mildew and powdery mildew can seriously affect the yield and quality of fruits and vegetables. Not only does it lead to a reduction in fruit and vegetable production, causing losses to agricultural production, but it also affects the beauty of leaves and fruits, reducing the economic value of fruits and vegetables. In addition, from June to July each year, fruits and vegetables are easily harmed by high temperatures and strong light, causing physiological diseases, which can cause poor plant growth, reduce yield and product quality, or even cause plant death.

[0003] At present, the prevention and control of fruit and vegetable pests and diseases mainly rely on chemical pesticides, but due to long-term, single use or abuse of insecticides (fungicides), pests and diseases have developed serious drug resistance, reducing the prevention and control effect, and also reducing the resistance of fruits and vegetables to stress. Therefore, inventing a plant protection agent with stress resistance, disease resistance and insect prevention is the key to solving these problems.

[0004] Kaolin is an economical, environmentally friendly, resource-rich and pure inert mineral. A large number of studies have confirmed that it can achieve pest control in agricultural production, and can also increase yield, alleviate abiotic stress, and improve crop quality. Therefore, kaolin can be used as a plant protection agent to replace chemical pesticides, used for plant pest control, alleviate high temperature and strong light stress, and improve crop yield and quality. At present, there are many studies on this type of plant protection agent, such as patent CN109769822A provides a new plant protection agent and its pest control method. A certain proportion of chitosan, kaolin, glycerol, glacial acetic acid, and water are fully stirred, then diluted by a certain multiple and sprayed on the plant. For example, patent CN102228017A discloses a plant anti-sunburn sunscreen and its preparation method and use. The plant sunscreen made of refined kaolin, titanium dioxide, dispersant NNO, water-soluble chitosan, etc., is sprayed on the surface of plants and forms a white loose coating after drying. It is used to prevent and control the sunburn of crops, fruit trees, vegetables, and flower seedlings caused by high temperature and strong light in summer. Practice has shown that the existing plant protection agents have significant stress resistance, disease resistance, and insect prevention effects in the early stage of use, but the duration of effect is short. The main reason is that the agents cannot adhere to the plants for a long time, and the coverage is not comprehensive. They are easily washed away by rain when exposed to the air, and the number of spraying needs to be increased, which not only affects the stress resistance, disease resistance, and insect prevention effects, but also increases the cost of use. Moreover, after multiple spraying, it will also cause serious adhesion on the fruit surface during the harvest period and difficult to clean.

[0005] Therefore, how to develop a plant protection agent with strong film-forming properties, resistance to rain erosion, easy cleaning, and good prevention and control effects is a technical problem that technical personnel in the field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention aims to provide a composition for preparing a protective agent, and to prepare a plant protective agent using the composition for use in plant protection.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A composition, characterized in that it comprises component A and component B, and the weight ratio of the two is A:B=30-60:40-70;

[0009] Component A includes the following ingredients in mass fractions: kaolin 97.80-99.45%, tea saponin 0.5-2.0%, and defoamer 0.05-0.2%;

[0010] Component B comprises the following ingredients in mass fractions: 0.01-0.4% of high acyl gellan gum and 99.6-99.99% of deionized water.

[0011] Preferably, the fineness of the kaolin is 800-2000 mesh.

[0012] Preferably, the defoaming agent is a silicone solid powder defoaming agent.

[0013] The composition is used in preparing a plant protection agent which has strong film-forming property, is resistant to rain erosion, is easy to clean and has good pest and disease prevention effect.

[0014] A plant protection agent, the raw materials of which include the composition.

[0015] The preparation method of the plant protection agent comprises:

[0016] (1) Weigh kaolin, tea saponin, and defoamer according to the ratio, and mix the three to obtain component A;

[0017] (2) adding a formulated amount of high acyl gellan gum to a formulated amount of deionized water, heating the mixture to 70-80° C., stirring the mixture to completely dissolve the high acyl gellan gum, and cooling the mixture to room temperature to obtain component B;

[0018] (3) Component A and component B are packaged separately and mixed in one system to obtain a plant protection agent.

[0019] The application method of the plant protection agent comprises the following steps: fully mixing component A and component B to uniformly disperse the component A and component B to form a suspension, diluting the suspension with water at a volume ratio of 1:20 to 25, and spraying the suspension for use.

[0020] It can be seen from the above technical scheme that the technical effect achieved by the present invention is: kaolin, high acyl gellan gum aqueous solution, tea saponin, and defoaming agent are combined in a specific ratio to prepare a plant protection agent, which solves the problems of poor rain erosion resistance, weak film-forming property, severe adhesion to the fruit surface during the harvest period, and difficulty in cleaning of existing plant protection agents, improves the prevention and control effect of diseases and pests, and at the same time increases the output of agricultural products, improves the commodity value, and is low in price and easy to use.

[0021] Specifically, the technical effects achieved by the present invention are:

[0022] (1) The plant protection agent of the present invention is made of kaolin, high acyl gellan gum aqueous solution, tea saponin, and defoamer, and has a simple preparation process, low cost, and is easy to use. Since all the raw materials in the formula are safe and environmentally friendly substances, it is suitable for direct application on fruits and vegetables. At the same time, high acyl gellan gum and tea saponin are both natural degradable substances, which solves the problem of obvious adhesion of drugs on the fruit surface during the harvest period. In addition, tea saponin also has the effect of cleaning and decontamination, making it easy to clean the residues of the plant protection agent in fruits and vegetables, thereby improving the quality of fruits and commodities.

[0023] (2) The plant protection agent of the present invention can stably adhere to the plant surface through the synergistic effect of kaolin, high acyl gellan gum aqueous solution, tea saponin and defoamer, and can form a protective film of a certain thickness after the water evaporates. The formed protective film not only has better spreading ability and rainwater erosion resistance, but also can block the invasion of pests and pathogens on plants, and can significantly improve the field control effect of fruit and vegetable pests. After spraying for 7 days, the control effect on tomato aphids and downy mildew is still above 73%, which is much higher than the control effect of existing plant protection agents. At the same time, it can also reduce the damage of the external environment to the plant, alleviate the stress of strong light and high temperature on the plant, slow down the transpiration of the plant leaves, and enhance the resistance of the plant to light, heat and water stress.

[0024] (3) The plant protection agent of the present invention also has a yield-increasing effect. According to tests, compared with the control area, the plant protection agent of the present invention can increase the weight of a single tomato fruit by 16.72-17.85% and increase the average single fruit diameter by 5.30-6.10%.

[0025] (4) The plant protection agent of the present invention forms a protective film on the surface of the plant, thereby reducing various environmental stresses such as light, heat, and water, inhibiting the invasion of pests and pathogens, and increasing production. Therefore, based on the application of the present invention to fruits and vegetables, it can be reasonably expected that it is also applicable to other crops, such as cotton, soybeans, wheat, potatoes and other economic crops, and has good protection and yield-increasing effects. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The components described in the following examples are all commercially available, the kaolin having a fineness range of 800-2000 mesh (Shijiazhuang Tourmaline Mineral Products Co., Ltd.); tea saponin (Jinhua Muchunyuan Tea Oil Technology Co., Ltd.); high acyl gellan gum (Zhenghong Biotechnology Co., Ltd.); the defoaming agent is a silicone solid powder defoaming agent (Guangdong Zhongke Hongtai New Materials Co., Ltd.).

[0028] Kaolin, unlike traditional pesticides, does not act directly on harmful organisms. Instead, it protects plants by forming a physical barrier on the surface of plants, thereby hindering the invasion of pests and pathogens. It can also reflect excess light and heat, thereby reducing leaf temperature and transpiration, alleviating damage to plants caused by high temperature and drought stress, and then regulating plant growth and metabolic balance, enabling plants to resist stress, resist diseases, prevent insects and increase yields.

[0029] High acyl gellan gum is a microbial polysaccharide produced by aerobic fermentation of Sphingomonas elodea, which has the characteristics of being non-toxic, safe to eat and degradable. Natural gellan gum is called high acyl gellan gum because it contains acetyl and glyceryl groups. It is a multifunctional hydrophilic colloid that integrates film agent, suspending agent, stabilizer and gelling agent. It is widely used in the food industry, pharmaceutical industry and cosmetics industry, and there is no report on its application in plant protection agents. In the present invention, the unique gel network structure of high acyl gellan gum is used to make the solid particles of plant protection agents form a stable suspension in water, prevent the sedimentation and aggregation of solid particles, thereby ensuring that the liquid medicine can be evenly distributed on the plant surface during the spraying process. In addition, it can also increase the adhesion of the liquid medicine on the plant surface, so that it can be attached to the plant for a long time, and improve the utilization rate and durability of the plant protection agent.

[0030] Tea saponin, also known as tea saponin, is a mixture of oleanane-type pentacyclic triterpenoid saponins extracted from the Camellia plants. It is composed of ligand (hydrophobic), saccharide (hydrophilic) and organic acid (hydrophobic). Because it contains hydrophilic and hydrophobic groups, tea saponin is a natural surfactant with excellent performance, which mainly plays the role of synergism, spreading, wetting and dispersion. It can improve the physical properties of pesticides and increase the adhesion of the liquid on the surface of organisms or plants, thereby playing a synergistic role for pesticides. It can also significantly reduce the surface tension of the liquid. In the concentration range of 0.01-1.0%, the surface tension of the aqueous solution can be reduced from 76mN / m to 46mN / m after adding tea saponin, so it has good wettability. Tea saponin is also a natural degradable substance that can be automatically degraded and is non-toxic. During the separation process, it will not affect the chemical properties of pesticides, is beneficial to the storage of pesticides, and does not pollute the environment. It meets the current sustainable development requirements of the pesticide industry and green environmental protection, and has good application prospects.

[0031] Example 1

[0032] A plant protection agent is made of two components, A and B. Component A comprises the following components by mass fraction: 98.66% kaolin, 1.2% tea saponin, and 0.14% defoamer; and component B comprises the following components by mass fraction: 0.2% high acyl gellan gum and 99.8% deionized water.

[0033] The weight ratio of the components in Example 1 is A:B=50:50.

[0034] The preparation process of plant protection agent is as follows:

[0035] (1) Weigh kaolin, tea saponin and defoamer according to the ratio and mix them evenly to obtain component A.

[0036] (2) Add the formulated amount of high acyl gellan gum to the formulated amount of deionized water, raise the temperature to 70-80° C., stir to completely dissolve the high acyl gellan gum, and cool to room temperature to obtain component B.

[0037] (3) Component A and component B are packaged separately and mixed in one system to obtain a plant protection agent.

[0038] Before application, mix component A and component B in proportion to form a suspension, dilute with water at a ratio of 1:25, and spray evenly on the plants on a windless and sunny day. The dosage of the liquid is 70-80 kg / mu.

[0039] Example 2

[0040] A plant protection agent is made of two components, A and B. Component A comprises the following components by mass fraction: 97.90% kaolin, 2.0% tea saponin, and 0.1% defoamer; and component B comprises the following components by mass fraction: 0.05% high acyl gellan gum and 99.95% deionized water.

[0041] The weight ratio of A and B = 58:42.

[0042] The preparation process and use method are the same as in Example 1.

[0043] Example 3

[0044] A plant protection agent is made of two components, A and B. Component A comprises the following components by mass fraction: 98.80% kaolin, 1.0% tea saponin, and 0.2% defoamer; and component B comprises the following components by mass fraction: 0.4% high acyl gellan gum and 99.6% deionized water.

[0045] The weight ratio of A and B = 30:70.

[0046] The preparation process and use method are the same as in Example 1.

[0047] Example 4

[0048] A plant protection agent is made of two components, A and B. Component A comprises the following components by mass fraction: 99.45% kaolin, 0.5% tea saponin, and 0.05% defoamer; and component B comprises the following components by mass fraction: 0.01% high acyl gellan gum and 99.99% deionized water.

[0049] The weight ratio of A and B = 60:40.

[0050] The preparation process and use method are the same as in Example 1.

[0051] Comparative Example 1

[0052] A comparative sample is composed entirely of kaolin and is used in the same manner as in Example 1.

[0053] Comparative Example 2

[0054] A comparative sample includes the following components in mass fractions: 99.33% kaolin, 0.6% tea saponin, and 0.07% defoaming agent.

[0055] The preparation process and use method are the same as in Example 1.

[0056] Comparative Example 3

[0057] A comparative sample is made of two components, A and B. Component A is kaolin; component B includes the following ingredients in mass fractions: 0.2% high acyl gellan gum and 99.8% deionized water.

[0058] The weight ratio of the components is A:B=50:50.

[0059] The preparation process and use method are the same as in Example 1.

[0060] Comparative Example 4

[0061] A comparative sample comprises the following components by mass fraction: 0.2% high acyl gellan gum and 99.8% deionized water.

[0062] The preparation process and use method are the same as in Example 1.

[0063] Performance Testing

[0064] In order to verify the performance of the plant protection agents prepared in the above Examples 1-4 and the comparative samples of Comparative Examples 1-4, a series of tests were conducted on the suspension rate, persistent foaming, fineness, resistance to rainwater erosion, and easy cleaning, and the field control effect and yield increase effect were measured. The control was a commercially available kaolin granular film product. WP (Engelhard, USA). All experiments were set up in three parallel groups or repeated three times. The test methods and results are as follows:

[0065] (I) Suspension rate, persistent foaming and fineness test

[0066] 1. Suspension rate test: Test according to the method of GB / T 14825-2023.

[0067] 2. Persistent foaming test: Tested according to the method of GB / T 28137-2011.

[0068] 3. Fineness test: Test according to the method of GB / T 16150-1995.

[0069] Table 1 Test results of sample suspension rate, persistent foaming and fineness

[0070]

[0071] Result analysis: The higher the suspension rate, the better the dispersion uniformity of the sample in the system, the higher the stability, and the more evenly distributed on the plant surface, ensuring the maximum efficacy. As shown in Table 1, the suspension rates of Examples 1-4 are 90-94%, which is comparable to the commercially available products. The suspension rate (90%) of WP is similar, and the test results of persistent foaming and fineness are up to standard, indicating that the formula of the plant protection agent obtained in the embodiment of the present invention is reasonable, and the suspension rate, persistent foaming and fineness are up to expectations.

[0072] The suspension rates of Comparative Examples 2 and 3 are 73% and 85%, respectively, which are higher than the suspension rate of Comparative Example 1 (62%), indicating that adding a certain amount of tea saponin or high acyl gellan gum aqueous solution to kaolin can improve the suspension effect of the sample.

[0073] The suspension rates of Examples 1-4 are between 90-94%, which are higher than those of Comparative Examples 1-3, indicating that the suspension rates of the samples are significantly improved through the synergistic effect of kaolin, high acyl gellan gum aqueous solution, tea saponin and defoamer.

[0074] (II) Rainwater erosion resistance test

[0075] Pick rape leaves of similar size and shape, wash off dust and other attachments on the leaves with water, dry them naturally indoors, select the leaves required for the test, divide them into 8 groups, each group has 10 leaves, measure the leaf area of ​​each leaf by the grid method, weigh them for later use. The test agent is the plant protection agent of the present invention obtained in Example 1-4, and the comparative samples and WP, 8 in total.

[0076] Each test agent was diluted with deionized water to prepare a 20-fold diluted solution, which was evenly sprayed on the rapeseed leaves and weighed. The amount of solution deposited on each leaf was subtracted from the weight of the rapeseed leaves, and the amount of test agent sprayed on each leaf was divided by the dilution factor. The leaves treated with the solution were naturally dried indoors and set aside.

[0077] The leaves treated with the liquid were placed 10 cm below the shower head and continuously rinsed with a shower intensity of 340 mL / min for 1 min. At the same time, the flowing liquid was collected in a plastic basin. The collected liquid was filtered on the double-layer filter paper of the special funnel of the filtration device, and then placed in a 54°C oven for 14 hours to dry. Then it was weighed and its residual rate was calculated. This was used as a basis to judge the rain erosion resistance of different agents.

[0078] Grid method to measure leaf area: Use a ruler to draw 1cm×1cm small squares on A4 paper to cover the entire page. Place the rapeseed leaf on the A4 paper and determine the leaf area based on the number of small squares occupied by the leaf. (For leaves with less than one square, count as one square if it is larger than half a square, and discard if it is smaller than half a square).

[0079] Artificially simulate rainfall intensity: Install the shower head on the faucet, slowly turn the switch, and observe the tap water dripping in the shower head. When the water flow is fast and the water drops can be clearly seen falling, place a 1L plastic beaker underneath, time for 1 minute, measure the water volume with a measuring cylinder, and adjust the rainfall intensity to 340mL / min.

[0080] Calculation of the residual rate w (%) of the test agent on the leaves:

[0081] w(%)=(m1-m2) / m1×100;

[0082] m1: the mass of the test agent on the leaves before slow water flushing;

[0083] m2: The mass of the test reagent remaining on the filter paper after drying.

[0084] The results are shown in Table 2;

[0085] Table 2 Comparison of rainwater erosion resistance of different tested agents

[0086]

[0087] Results analysis: Under the condition of basically the same adhesion amount per unit area, the higher the residual rate of the tested agent, the better the rainwater erosion resistance. As can be seen from Table 2, the residual rates of samples 1-4 in this embodiment on rapeseed leaves are all above 57%, while the control The residual rate of WP is 43.54%, indicating that the rainwater erosion resistance of the plant protection agent obtained in the embodiment of the present invention is better than that of the commercially available product. WP.

[0088] The residual rate of comparative example 3 on rapeseed leaves is 54.09%, which is significantly higher than the residual rate of comparative example 1 (30.71%), indicating that the addition of a certain amount of high acyl gellan gum aqueous solution to kaolin can significantly improve the rain erosion resistance of the sample.

[0089] By comparing the residual rates of Examples 1-4 and Comparative Examples 1-3 on rapeseed leaves, it was found that the residual rates of Examples 1-4 were between 57.08% and 66.74%, which were all higher than the residual rates of Comparative Examples 1-3 (30.71% to 54.09%), indicating that kaolin, high acyl gellan gum aqueous solution, tea saponin and defoaming agent in the formulation of the present invention can play a synergistic role, significantly improving the rain erosion resistance of the plant protection agent obtained in the examples.

[0090] (III) Cleanability test

[0091] The test site was selected to be a tomato field with consistent cultivation and management conditions, medium and consistent soil fertility, and no other pesticides were used before and during the test. During the field test, the samples obtained in Examples 1-4 and Comparative Examples 1, 2, and 3 were used as treatment agents, and a WP is the control agent, and each treatment area is 100m 2 , each treatment is separated by a guard row.

[0092] Spray the pesticide during the fruiting period of tomatoes. In each treatment area, dilute the test pesticide for each treatment 20 times and spray evenly. The dosage of the pesticide solution is 80 kg / mu. After 7 days, the five-point sampling method is used for sampling. 5 tomato plants are selected at each point. 2 fruits are randomly picked from each tomato plant for testing. The tomatoes picked from each treatment area are weighed (m1), soaked in 1000mL 0.5% salt water for 10 minutes, rinsed with running water for 1 minute, and the water flowing down is caught in a plastic basin. The tomatoes are naturally dried and weighed again (m2). Continue to wash until there is no pesticide residue on the surface of the tomatoes, dry naturally, weigh again (m3), and wash with clean water for control. Calculate the pesticide removal rate on the surface of tomato fruits in each treatment area, and use this as a basis to judge the easy cleanability of the pesticide used in each treatment.

[0093] Calculation of the drug removal rate w (%) of tomato fruit:

[0094] w=[(m1-m2) / (m1-m3)]×100%;

[0095] m1: the mass of tomatoes with chemicals attached before washing;

[0096] m2: the mass of tomatoes with chemicals attached after washing;

[0097] m3: The quality of tomatoes after thorough washing.

[0098] The results are shown in Table 3.

[0099] Table 3 Removal effect of pesticides on tomato surface in different pesticide treatment areas

[0100]

[0101]

[0102] Results analysis: Under the same cleaning conditions, the higher the pesticide removal rate, the less pesticide residue on tomatoes and the better the cleaning performance. As can be seen from Table 3, 7 days after the pesticide was sprayed on tomatoes during the fruiting period, the tomatoes were washed with 0.5% salt water. The removal rates of Examples 1-4 were all above 83%, while the control The removal rate of WP is 61.44%, indicating that the plant protection agent obtained in the embodiment of the present invention is easier to clean than the commercially available product. WP, and washed with 0.5% saline, Examples 1-4 and The removal rate of WP is much higher than that of water washing. Therefore, after the tomato fruit is harvested, washing with salt water can effectively remove the residues of plant protection agents in the tomato.

[0103] It can also be seen from Table 3 that under the same cleaning conditions, the removal rates of Examples 1-4 and Comparative Example 2 are significantly higher than those of Comparative Example 1 and Comparative Example 3. This indicates that adding a certain amount of tea saponin to the formulation of the present invention can play a cleaning role and improve the easy washing property of tomatoes.

[0104] (IV) Field control experiment

[0105] The test site was selected to be a tomato field with consistent cultivation and management conditions, medium and consistent soil fertility, and no other pesticides were used before and during the test. The samples obtained in Examples 1-4 and Comparative Examples 1-4 were used as treatment agents, and a WP is the control agent, and each treatment area is 100m 2 Each treatment was separated by a protective row. The pesticide was sprayed at the initial flowering stage of tomatoes or the peak period of aphid nymphs. The test pesticide for each treatment was diluted 20 times and sprayed evenly. The dosage of the liquid was 80 kg / mu.

[0106] For the investigation of control effects, a five-point sampling method was used in each treatment area. Five tomato plants were selected at each point, and 5 leaves were selected from the upper, middle and lower parts of each tomato plant. The number of aphids and the number of downy mildew leaves on the plants in each treatment area were investigated before application of the pesticide and 7 and 18 days after application of the pesticide, and the control effect was calculated. The treatment without application of the pesticide was used as a blank control.

[0107] Control effect (%) = [number of aphids in the control group (number of leaves with downy mildew) - number of aphids in the treatment group (number of leaves with downy mildew)] / number of aphids in the control group (number of leaves with downy mildew) × 100. The results are shown in Table 4.

[0108] Table 4 The control effect of different pesticides on tomato aphids and downy mildew

[0109]

[0110] As can be seen from Table 4, 7 days after application, the control effect of Examples 1-4 on tomato aphids was 82.21-86.56%, which was better than the commercially available products. WP has a protective effect (59.29%); Examples 1-4 have a protective effect of 73.74-78.79% on tomato downy mildew, which is better than WP was 43.43%. 18 days after application, the control effect of Example 1-4 on tomato aphids was about 35%, which was better than WP has a control effect on tomato aphids (16.97%); Examples 1-4 have a control effect on tomato downy mildew of 31.15-34.97%, which is better than This shows that the control effect of Examples 1-4 of the present invention on tomato aphids and downy mildew is significantly better than that of commercially available products The control effect of WP on tomato aphids and downy mildew.

[0111] It can also be seen from Table 4 that after 7 days of spraying, the control effects of Comparative Example 3 on tomato aphids and downy mildew were 61.26% and 46.46%, respectively, which were higher than 32.41% and 26.26% of Comparative Example 1, indicating that the present invention adds a high acyl gellan gum aqueous solution to kaolin, and a uniform protective agent film is formed on the plant surface after spraying, which significantly improves the disease resistance and insect prevention effects of the sample.

[0112] It can also be seen from Table 4 that there is a significant difference in the control effect of Examples 1-4 and Comparative Examples 1-4 on tomato aphids and downy mildew. Seven days after application, the control effect of Examples 1-4 on tomato aphids and downy mildew was above 73%, while the control effect of Comparative Examples 1-4 was 23.72-61.26%; similarly, 18 days after spraying, the control effect of Examples 1-4 was higher than that of Comparative Examples 1-4. This indicates that the kaolin, high acyl gellan gum aqueous solution, tea saponin and defoamer in the components of the present invention work together to improve the control effect of the plant protection agent on tomato aphids and downy mildew.

[0113] (V) Test on the impact on fruit and vegetable yield

[0114] Yield determination was carried out in the same test field as above. In the WP treatment area, a five-point sampling method was adopted, and 5 tomato plants were selected at each point. Two fruits were randomly picked from each tomato plant, washed, dried naturally, weighed, and their yield was determined. The treatment without application of plant protection agents was used as a blank control.

[0115] Growth rate (%) = [average single fruit weight (average single fruit diameter) of the treatment group - average single fruit weight (average single fruit diameter) of the control group] / average single fruit weight (average single fruit diameter) of the control group × 100. The results are shown in Table 5.

[0116] Table 5 Effects of different pesticides on tomato yield

[0117]

[0118] As can be seen from Table 5, when the tomato was sprayed with Examples 1-4 during its growth, the average single fruit weight was 193.44-195.31 g, which was higher than that of the tomato sprayed with the commercially available product. WP was 181.07g, which was 16.72-17.85% higher than the blank control; at the same time, it also had a significant effect on increasing the diameter of single tomato fruits. The average single tomato fruit diameter after spraying Examples 1-4 was 72.98-73.54mm, which was larger than that after spraying commercially available products. The average single fruit diameter of WP is 72.01 mm, which is 5.30-6.10% higher than the average single fruit diameter of the blank control (69.31 mm). This indicates that the plant protection agent obtained in the embodiment of the present invention can significantly increase the single fruit weight and single fruit diameter of tomato fruits, has a yield-increasing effect, and improves its commercial value.

[0119] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0120] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A composition, characterized in that It comprises component A and component B, and the weight ratio of the two is A:B=30-60:40-70; Component A includes the following ingredients in mass fractions: kaolin 97.80-99.45%, tea saponin 0.5-2.0%, and defoamer 0.05-0.2%; Component B comprises the following ingredients in mass fractions: 0.01-0.4% of high acyl gellan gum and 99.6-99.99% of deionized water.

2. The composition according to claim 1, characterized in that The fineness of the kaolin is 800-2000 mesh.

3. The composition according to any one of claim 1, characterized in that The defoamer is a silicone solid powder defoamer.

4. Use of the composition according to claim 1 in preparing a plant protection agent having strong film-forming property, being resistant to rain erosion, being easy to clean and having good pest and disease control effect.

5. A plant protection agent, characterized in that: The raw material comprises the composition according to claim 1.

6. The method for preparing the plant protection agent according to claim 5, characterized in that: The process includes: (1) Weigh kaolin, tea saponin, and defoamer according to the ratio, and mix the three to obtain component A; (2) adding a formulated amount of high acyl gellan gum to a formulated amount of deionized water, heating the mixture to 70-80° C., stirring the mixture to completely dissolve the high acyl gellan gum, and cooling the mixture to room temperature to obtain component B; (3) Component A and component B are packaged separately and mixed in one system to obtain a plant protection agent.

7. The method for applying the plant protection agent according to claim 6, characterized in that: Mix component A and component B thoroughly and disperse them evenly to form a suspension, dilute with water at a volume ratio of 1:20-25 for suspension:water, and use by spraying.

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