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

Abstract

The invention provides a novel plant protective agent as well as a preparation method and application thereof. Belongs to the technical field of pesticides. The novel plant protective agent is prepared through cooperation of the diatomite, the saponin powder, the chitosan and the powdery organic silicon, the plant protective agent can be rapidly wetted and spread on the body surfaces of plants, insect bodies and pathogenic bacteria, the rainwater washing resistance is high, a protective film is formed on the plants, the specific structure function of the diatomite can be used for killing insects, and the plant protective agent has the advantages of being environmentally friendly and free of pollution. And the protective film can be used for preventing diseases and insect pests on the surfaces of plants, has a good prevention and treatment effect on diseases and insect pests of fruits and vegetables when used in the field, increases the yield of the fruits and vegetables, makes the fruits and vegetables easier to clean, and significantly improves the commodity value of the fruits and vegetables.

Description

Technical Field

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

[0002] Small pests such as whiteflies, thrips, and red spiders seriously affect the growth of Solanaceae vegetables and fruits. At present, the main method of prevention and control is chemical pesticides. Because small pests reproduce quickly, excessive use of chemical pesticides during prevention and control can control the occurrence and spread of pests in the short term, but it also brings many disadvantages. It not only pollutes the environment, destroys the ecological balance, kills natural enemies, but also makes pests resistant to drugs. It neither meets the development requirements of modern agriculture nor meets the needs of continuous control of pests and diseases and standardized agricultural production.

[0003] Diatomaceous earth is a widely distributed siliceous sedimentary rock, which is easy to grind into powder, has strong adsorption, has natural insecticidal activity, and is harmless to humans and natural enemies of pests. Therefore, diatomaceous earth can be used as a plant protection agent to replace chemical pesticides, and is used to control a variety of small pests on vegetables and fruit trees. For example: Patent CN112120019A, a biological pesticide insecticide composition and its preparation method and application, diatomaceous earth is compounded with insect attractants such as n-hexanol and 6-methyl-5-heptene-2-one, and the control of pests is changed from the original passive contact to active attraction, thereby improving the control efficiency. Another example: Patent CN109769856A, diatomaceous earth insecticide, its preparation method and application, discloses a diatomaceous earth insecticide composed of modified diatomaceous earth obtained by polysilazane modification as an active component, an appropriate amount of auxiliary component, a filler component and water, which has the advantages of non-toxicity, no drug resistance, and high insecticidal efficiency. It can be seen that the existing plant protection agents are mostly studied for insecticidal effects, and there are few studies on rainwater erosion resistance and film-forming properties. In addition, the existing plant protection agents often have problems such as poor rainwater erosion resistance, weak film-forming properties, and difficulty in cleaning during use, which affects the insecticidal effect and increases the difficulty of cleaning.

[0004] Therefore, how to develop a new type of plant protection agent with strong film-forming property, rain erosion resistance, easy cleaning and good prevention and control effect is a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] In view of this, the present invention provides a novel plant protection agent and a preparation method and application thereof. Diatomaceous earth, saponin powder, chitosan and powdered silicone are combined in a specific ratio to prepare the novel plant protection agent, which solves the problems of poor resistance to rain erosion, weak film-forming property, 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 and improves the commodity value.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A novel plant protection agent comprises the following components in percentage by weight:

[0008] 97.5-99.7% diatomaceous earth;

[0009] 0.1-0.5% sapodilla powder;

[0010] 0.1-0.5% chitosan;

[0011] 0.1-1.5% powdered silicone.

[0012] Another object of the present invention is to provide: a novel plant protection agent comprising the following components in percentage by weight:

[0013] 98.5-99.5% diatomaceous earth;

[0014] 0.1-0.2% sapodilla powder;

[0015] 0.1-0.3% chitosan;

[0016] 0.3-1.0% powdered silicone.

[0017] Another object of the present invention is to provide: a novel plant protection agent comprising the following components in percentage by weight:

[0018] 98.95% diatomaceous earth;

[0019] 0.15% saponin powder;

[0020] 0.2% chitosan;

[0021] 0.7% powdered silicone.

[0022] The beneficial effects of the above operation are:

[0023] Diatomaceous earth, on the one hand, has a rough surface with many irregular needle-like protrusions, which can scratch the insect's body surface, destroy the insect's waxy protective layer, and make the insect lose its ability to retain water; on the other hand, diatomaceous earth's porous structure and hydrophilicity further absorb the moisture in the insect's body, accelerating the insect's dehydration and death;

[0024] Gleditsia powder, the main component of which is saponin, can reduce the surface tension between the liquid medicine and the plant, making it easier for the plant protection agent to adhere to the plant surface, playing the role of wetting, suspending, dispersing, and resisting rain erosion. It also has a cleaning effect, making fruits and vegetables easier to clean;

[0025] Water-soluble chitosan forms a uniform thin film on the surface of the plant after spraying, which can block the exchange of substances inside and outside the cells, reduce water metabolism, reduce the consumption of nutrients in the respiration of fruits and vegetables, and block the entry of foreign microorganisms and pollutants, effectively inhibiting the reproduction of microorganisms; it plays a film-forming and antibacterial role.

[0026] Powdered silicone mainly plays the role of wetting, anti-rainwater erosion, and dispersion. Liquid polyether-modified trisiloxane is added to white carbon black, and powdered silicone is prepared by taking advantage of the large specific surface area and strong adsorption of white carbon black. Its active ingredient is polyether-modified trisiloxane, which is composed of a trisiloxane main chain and a polyether side chain. It is adsorbed on the air / water interface with a unique "umbrella-shaped" structure, reducing the surface tension to about 20mN / m. The contact angle formed on the hydrophobic interface is small, so it can quickly wet and spread on the plant leaves, so that the agent can achieve maximum coverage and adhesion. Because its surface tension is below the critical pressure of leaf wetting (about 25mN / m), it can promote the penetration of the liquid medicine into the epidermis through the pores, thereby reducing the erosion of rainwater. The white carbon black in the powdered silicone plays a certain suspension role in the system.

[0027] Preferably, the main component of the diatomaceous earth is amorphous SiO2, and the fineness range is 800-2000 mesh.

[0028] Preferably, the chitosan is water-soluble chitosan with a deacetylation degree of ≥90%.

[0029] The beneficial effects of the above operation are: chitosan has a high degree of deacetylation and a high content of free amino groups, and its antibacterial effect is better; and chitosan with a high degree of deacetylation has a shorter molecular chain, a larger space between molecules, and an increased degree of freedom of molecular movement, which is conducive to the mutual adsorption and cross-linking between chitosan molecules, thereby promoting film formation.

[0030] Preferably, the powdered silicone active ingredient is polyether-modified trisiloxane.

[0031] Preferably, the novel plant protection agent is in the form of a wettable powder.

[0032] Another object of the present invention is to provide a method for preparing the novel plant protection agent, comprising the following steps:

[0033] (1) Weighing sapodilla powder, chitosan and powdered organosilicon according to a ratio, mixing the three, and crushing them to obtain a mixed product 1;

[0034] (2) Add diatomaceous earth to the mixed product 1 according to the proportion, mix thoroughly, and obtain a new plant protection agent.

[0035] Another object of the present invention is to provide: application of the novel plant protection agent in pest control.

[0036] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The novel plant protection agent of the present invention is green and environmentally friendly, pollution-free, has a wide range of raw material sources, is simple in production process, low in cost, convenient in application, and has a long duration of efficacy.

[0038] (2) Through the synergistic effect of diatomaceous earth, saponin powder, chitosan, and powdered silicone, the liquid medicine can quickly wet and spread on the surface of plants, insects, and pathogens, and has strong resistance to rain erosion, and forms a protective film on the plants. The specific structural function of diatomaceous earth itself can be used to kill insects, and the protective film can be used to prevent diseases and pests on the surface of plants. When used in the field, it has a good control effect on fruit and vegetable diseases and pests, and can also increase its yield. The saponin powder has a cleaning effect, making fruits and vegetables easier to clean, significantly improving the commercial value of fruits and vegetables.

[0039] (3) At the same time, the powdered organosilicon in the formula can significantly enhance the adhesion and spreading force of diatomaceous earth on the surface of plants or pests due to its excellent wettability and permeability. It not only improves the insecticidal effect, but also reduces the number of spraying times and the amount of plant protection agents used. DETAILED DESCRIPTION

[0040] 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 making creative work are within the scope of protection of the present invention.

[0041] The components described in the following examples are all commercially available. The main component of the diatomaceous earth is amorphous SiO2 with a fineness range of 800-2000 mesh (Tianjin Zhongke New Materials Co., Ltd.); chitosan is water-soluble chitosan with a deacetylation degree ≥90% (Shandong Daxu Bioengineering Co., Ltd.); the powdered silicone active ingredient is polyether-modified trisiloxane (Jiangxi Tiansheng New Materials Co., Ltd.); the new plant protection agent is in the form of a wettable powder.

[0042] Example 1

[0043] A novel plant protection agent comprises the following components in percentage by weight: 98.95% diatomaceous earth, 0.15% sapodilla powder, 0.2% chitosan and 0.7% powdered organosilicon.

[0044] The preparation process of the new plant protection agent is as follows:

[0045] (1) weighing sapodilla powder, chitosan and powdered organosilicon according to the above weight percentages, and subjecting them to high-speed universal pulverization so that they can be uniformly mixed with each other and have a fineness range similar to that of diatomaceous earth;

[0046] (2) Then, diatomaceous earth is added and shaken in a ziplock bag. After 10 minutes, the mixture is transferred to a flask and stirred and mixed with a stirrer at 70 rpm for 30 minutes to obtain a new plant protection agent.

[0047] When using, dilute it 30 times and spray it evenly on the plants.

[0048] Example 2

[0049] A novel plant protection agent comprises the following components in percentage by weight: 99.25% diatomaceous earth, 0.1% sapodilla powder, 0.15% chitosan and 0.5% powdered organosilicon.

[0050] The preparation process and use method of the new plant protection agent are the same as those in Example 1.

[0051] Example 3

[0052] A novel plant protection agent comprises the following components in percentage by weight: 98.5% diatomaceous earth, 0.2% sapodilla powder, 0.3% chitosan and 1.0% powdered organosilicon.

[0053] The preparation process and use method of the new plant protection agent are the same as those in Example 1.

[0054] Example 4

[0055] A novel plant protection agent comprises the following components in percentage by weight: 99.45% of diatomaceous earth, 0.15% of saponin powder, 0.1% of chitosan and 0.3% of powdered organosilicon.

[0056] The preparation process and use method of the new plant protection agent are the same as those in Example 1.

[0057] In order to verify the effect of each component in the formula and whether there is any interaction between the components in the formula, comparative samples were prepared, see Comparative Examples 1-6.

[0058] Comparative Example 1

[0059] A comparative sample, composed entirely of diatomaceous earth, was used in the same manner as in Example 1.

[0060] Comparative Example 2

[0061] A comparative sample includes the following components in weight percentage: 99.85% diatomaceous earth and 0.15% sapodilla powder. The preparation process and use method are the same as in Example 1.

[0062] Comparative Example 3

[0063] A comparative sample includes the following components in weight percentage: 99.3% diatomaceous earth and 0.7% powdered organosilicon. The preparation process and use method are the same as those in Example 1.

[0064] Comparative Example 4

[0065] A comparative sample includes the following components in weight percentage: 99.8% diatomaceous earth and 0.2% chitosan. The preparation process and use method are the same as in Example 1.

[0066] Comparative Example 5

[0067] A comparative sample includes the following components in weight percentage: 0.15% sapodilla powder, 0.2% chitosan, and 99.65% powdered organosilicon. The preparation process and use method are the same as those in Example 1.

[0068] Comparative Example 6

[0069] A comparative sample includes the following components in weight percentage: 99.65% diatomaceous earth, 0.15% saponin powder, and 0.2% chitosan. The preparation process and use method are the same as in Example 1.

[0070] Performance Testing

[0071] In order to verify the performance of the novel plant protection agent prepared in the above Examples 1-4 and the comparative samples of Comparative Examples 1-6, a series of tests were conducted on them, including suspension rate, wetting time, persistent foaming, fineness, resistance to rainwater erosion, and easy cleaning, and field control effect and yield increase effect were measured, and the control was a similar plant protection agent Celite mineral powder (produced in Mexico). All tests were set up in three parallel groups or repeated three times. The test methods and results are as follows:

[0072] (I) Suspension rate, wetting time, persistent foaming, and fineness test

[0073] 1. Suspension rate test: Test according to the method of GB / T 14825-2006. Summary: Use standard hard water to prepare the sample to be tested into a suspension of appropriate mass concentration. Under the specified conditions, let it stand in a measuring tube for a certain period of time, remove the upper 9 / 10 of the suspension, and use the weight method to determine the mass of the residue in the bottom 1 / 10 of the suspension to calculate the suspension rate.

[0074] 2. Wetting time test: Test according to the method of GB / T 5451-2001. Summary: Pour a certain amount of wettable powder into a beaker filled with a certain amount of standard hard water from a specified height, and measure the time it takes to be completely wetted.

[0075] 3. Persistent foaming test: Test according to the method of GB / T 28137-2011. Summary: Mix the specified amount of sample with standard hard water, let it stand for 1 minute, and then record the foam volume.

[0076] 4. Fineness test: Test according to the method of GB / T 16150-1995. Summary: Wet and dilute the weighed sample in a beaker, pour it into a wet 325-mesh standard test sieve, rinse it directly with a gentle tap water flow, then place the test sieve in a basin of water to continue washing, transfer the residue in the sieve to a beaker, dry it, weigh it, and calculate the fineness.

[0077] Table 1 Test results of sample suspension rate, wetting time, persistent foaming and fineness

[0078]

[0079] Result analysis: The higher the suspension rate, the better the dispersion uniformity of the sample and the higher the stability. The shorter the wetting time, the better the wetting performance of the sample, which can quickly attach to the surface of pests or plants and evenly distribute to ensure the maximum efficacy. The synergistic effect between diatomaceous earth, saponin powder, chitosan and powdered silicone significantly improved the suspension rate of the sample and reduced its wetting time. As shown in Table 1:

[0080] (1) Compared with Comparative Examples 1-3 and Celite mineral powder, Examples 1-4 have higher suspension rates and shorter wetting times, and all test results meet the standards;

[0081] (2) The suspension rate and wetting time of Comparative Example 2 were 78% and 69s, respectively. Compared with Comparative Example 1, the suspension rate was high and the wetting time was short, indicating that adding a certain amount of saponin powder to diatomaceous earth can play a role in wetting, suspension and dispersion;

[0082] (3) The suspension rate and wetting time of Comparative Example 3 were 83% and 49s, respectively. Compared with Comparative Example 1, the suspension rate was high and the wetting time was short, indicating that adding a certain amount of powdered organosilicon to diatomaceous earth can play a role in wetting, suspension and dispersion.

[0083] (II) Rainwater erosion resistance test

[0084] Pick rape leaves of similar size and shape, wash away 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 agents are the plant protection agents of the present invention obtained in Examples 1-4, the comparative samples obtained in Comparative Examples 1-3 and Celite mineral powder, a total of 8.

[0085] Each test agent was diluted with deionized water to prepare a 30-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.

[0086] The leaves treated with the liquid were placed 10 cm below the shower head and continuously irrigated at 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 a double-layer filter paper in a special funnel of a 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 embodiments.

[0087] 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).

[0088] 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.

[0089] Calculation of the residual rate w (%) of the test agent on the leaves:

[0090] w(%)=(m1-m2) / m1×100;

[0091] m1: the mass of the test agent on the leaves before slow water flushing;

[0092] m2: The mass of the test reagent remaining on the filter paper after drying.

[0093] Table 2 Comparison of rainwater erosion resistance of different tested agents

[0094]

[0095] Results analysis: When the amount of attachment per unit area is basically the same, the higher the residual rate of the tested agent, the better the rain 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 30%, while the residual rate of the control Celite mineral powder is 22.25%, indicating that the rain erosion resistance of the new plant protection agent obtained in the embodiment of the present invention is better than that of the commercially available plant protection agent product Celite mineral powder.

[0096] The residual rates of Comparative Examples 2 and 3 on rapeseed leaves were 21.94% and 29.14%, respectively, which were significantly higher than the residual rate of Comparative Example 1 (12.90%), indicating that adding a certain amount of saponin powder or powdered silicone to diatomaceous earth can make it resistant to rain erosion.

[0097] 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 32.24% and 37.19%, which were higher than the residual rates of Comparative Examples 1-3 (12.90% to 29.14%), indicating that diatomaceous earth, saponin powder, chitosan, and powdered silicone in the formulation of the present invention can play a synergistic role and significantly improve the rain erosion resistance of the plant protection agent.

[0098] (III) Cleanability test

[0099] The test site was selected to be a tomato field with consistent cultivation and management conditions, medium and consistent soil fertility, and no other agents were used before and during the test. During the field test, the samples obtained in Examples 1-4 and Comparative Examples 1 and 2 were used as treatment agents, and Celite mineral powder was set as a control agent. Each treatment area was 100m 2 , each treatment is separated by a guard row.

[0100] Spray the pesticide during the fruiting period of tomatoes. In each treatment area, dilute the test pesticide for each treatment by 30 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.

[0101] Calculation of the drug removal rate w (%) of tomato fruit:

[0102] w=[(m1-m2) / (m1-m3)]×100%;

[0103] m1: the mass of tomatoes with chemicals attached before washing;

[0104] m2: the mass of tomatoes with chemicals attached after washing;

[0105] m3: The quality of tomatoes after thorough washing.

[0106] Table 3 Removal effect of pesticides on tomato surface in different pesticide treatment areas

[0107]

[0108]

[0109] Under the same cleaning conditions, the higher the removal rate of the pesticide, the less pesticide residue in tomatoes and the better the ease of cleaning. As can be seen from Table 3, 7 days after the pesticide was sprayed during the fruiting period of tomatoes, 0.5% saline was used to clean the tomatoes. The results showed that the removal rates of the samples of Examples 1-4 were all above 80%, while the removal rate of the control Celite mineral powder was 58.42%, indicating that the easy cleaning of the new plant protection agent obtained in the examples of the present invention is better than that of the commercially available plant protection agent product Celite mineral powder, and the removal rates of Examples 1-4 and Celite mineral powder using 0.5% saline for cleaning are much higher than those of cleaning with clean water. Therefore, after the tomato fruit is harvested, cleaning with saline can effectively remove the residues of the plant protection agent in the tomato.

[0110] 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 60.20% and 36.22% of Comparative Example 1. This indicates that adding a certain amount of saponin powder to the formulation of the present invention can play a cleaning role and improve the easy washing property of tomatoes.

[0111] (IV) Field control experiment

[0112] The test site was selected from a tomato field with consistent cultivation and management conditions, medium and consistent soil fertility, and no other agents were used before and during the test. The samples obtained in Examples 1-4 and Comparative Examples 1, 4, 5, and 6 were used as treatment agents, and Celite mineral powder was set as a control agent. Each treatment area was 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 whitefly nymphs. The test pesticide for each treatment was diluted 30 times and sprayed evenly. The dosage of the liquid was 80 kg / mu.

[0113] For the investigation of control effects, in each treatment area, a five-point sampling method was adopted, 5 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 whiteflies and the number of leaves with gray mold on the plants in each treatment area were investigated before application on the day of application and 7 and 18 days after application, and the control effects were calculated. The treatment without application of the pesticide was used as a blank control.

[0114] Control effect (%) = [the number of whiteflies in the control group (the number of leaves with gray mold) - the number of whiteflies in the treatment group (the number of leaves with gray mold)] / the number of whiteflies in the control group (the number of leaves with gray mold) × 100.

[0115] Table 4 The control effect of different pesticides on tomato whitefly and gray mold

[0116]

[0117] As can be seen from Table 4, 7 days after application, the control effect of Examples 1-4 on tomato whiteflies was 84.50% to 90.50%, which was better than the control effect of the commercially available product Celite mineral powder (61.50%); the control effect of Examples 1-4 on tomato gray mold was 27.72% to 32.67%, which was better than the control effect of Celite mineral powder on tomato gray mold (9.9%). 18 days after application, the control effect of Examples 1-4 on tomato whiteflies was 33.46% to 38.40%, which was better than the control effect of Celite mineral powder on tomato whiteflies (15.97%); the control effect of Examples 1-4 on tomato gray mold was 19.21% to 23.73%, which was better than the control effect of Celite mineral powder on tomato gray mold (5.08%). This indicates that the control effects of Examples 1-4 of the present invention on tomato whitefly and gray mold are significantly better than the control effects of Celite mineral powder, a commercially available plant protection agent, on tomato whitefly and gray mold.

[0118] It can also be seen from Table 4 that after 7 days of spraying, the control effect of Examples 1-4 and Comparative Example 4 on gray mold was 24.75% to 32.67%, while the control effect of Comparative Example 1 was only 4.95%, indicating that the present invention adds chitosan to diatomaceous earth, and after spraying, a uniform thin film will be formed on the plant surface, which plays a film-forming and antibacterial role.

[0119] It can also be seen from Table 4 that there are significant differences in the control effects of Example 1, Comparative Examples 5 and 6 on tomato whiteflies. Seven days after application, the control effect of Example 1 was 90.50%, the control effect of Comparative Example 6 was 59.50%, and the control effect of Comparative Example 5 was only 18.50%; 18 days after spraying, the control effects of the three tested agents on tomato whiteflies were ranked the same as 7 days after spraying, Example 1>Comparative Example 6>Comparative Example 5. This shows that the addition of powdered organosilicon in the present invention will play a synergistic role with diatomaceous earth in the control of tomato whiteflies.

[0120] (V) Test on the impact on fruit and vegetable yield

[0121] Yield determination was carried out in the same test site as above. During the ripening period of tomato fruits, five-point sampling method was adopted in the areas treated with Examples 1-4 and Celite mineral powder, and five 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 applying plant protection agent was used as blank control.

[0122] 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

[0123] Table 5 Effects of different pesticides on tomato yield

[0124]

[0125] It can be seen from Table 5 that when Examples 1-4 were sprayed during the growth of tomatoes, the average single fruit weight was 189.98-193.93 g, which was higher than the average single fruit weight of the commercially available Celite mineral powder (179.87 g), and increased by 12.47-14.81% compared with the average single fruit weight of the blank control (168.91 g); it can also be seen from Table 5 that the average single fruit diameter of tomatoes after spraying Examples 1-4 was 72.12-73.13 mm, which was greater than the average single fruit diameter of the commercially available Celite mineral powder (71.01 mm), and increased by 3.58-5.03% compared with the average single fruit diameter of the blank control (69.63 mm), indicating that the new plant protection agent obtained in the examples of the present invention can increase the single fruit weight and single fruit diameter of tomato fruits, and has a significant yield-increasing effect.

[0126] The various embodiments in the 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.

[0127] 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 novel plant protection agent, characterized in that: The composition comprises the following weight percentages: 97.5-99.7% diatomaceous earth; 0.1-0.5% sapodilla powder; 0.1-0.5% chitosan; 0.1-1.5% powdered silicone.

2. A novel plant protection agent, characterized in that: The composition comprises the following weight percentages: 98.5-99.5% diatomaceous earth; 0.1-0.2% sapodilla powder; 0.1-0.3% chitosan; 0.3-1.0% powdered silicone.

3. A novel plant protection agent, characterized in that: The composition comprises the following weight percentages: 98.95% diatomaceous earth; 0.15% sapodilla powder; 0.2% chitosan; 0.7% powdered silicone.

4. The novel plant protection agent according to any one of claims 1 to 3, characterized in that: The main component of the diatomaceous earth is amorphous SiO2, and the fineness range is 800-2000 mesh.

5. The novel plant protection agent according to any one of claims 1 to 3, characterized in that: The chitosan is water-soluble chitosan, and the deacetylation degree is ≥90%.

6. The novel plant protection agent according to any one of claims 1 to 3, characterized in that: The powdered organic silicon effective component is polyether-modified trisiloxane.

7. The novel plant protection agent according to any one of claims 1 to 6, characterized in that: The formulation of the novel plant protection agent is a wettable powder.

8. The method for preparing the novel plant protection agent according to any one of claims 1 to 7, characterized in that: The steps include: (1) Weighing sapodilla powder, chitosan and powdered organosilicon according to a ratio, mixing and crushing the three, and obtaining a mixed product 1; (2) Add diatomaceous earth to the mixed product 1 according to the proportion, mix thoroughly, and obtain a new plant protection agent.

9. Use of the novel plant protection agent according to any one of claims 1 to 7 or the novel plant protection agent prepared by the preparation method of claim 8 in pest control.

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