Dispersible oil suspending agent for preventing and treating potato late blight as well as preparation method and application of dispersible oil suspending agent

Abstract

The invention relates to a dispersible oil suspending agent for preventing and treating potato late blight and a preparation method and application thereof, and relates to the field of pesticides, the dispersible oil suspending agent comprises the following raw materials by weight: 5-25% of mandipropamid, 5-25% of cymoxanil, 5-20% of a dispersant, 5-20% of an emulsifier, 2-5% of sodium carboxymethyl cellulose, and 27-65% of solvent oil 200 #. Field control experiments show that the dispersible oil suspending agent for preventing and treating potato late blight can effectively prevent and treat potato late blight, is safe and remarkable in prevention and treatment effect, and has no adverse effect on other diseases and insect pests and no adverse effect on non-target organisms.

Description

Technical Field

[0001] This invention relates to the field of pesticides, and in particular to a dispersible oil suspension for controlling potato late blight, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.

[0003] Diyrylamide is an inhibitor of phospholipid biosynthesis and cell wall synthesis. This compound is a preventative foliar fungicide with certain therapeutic functions. It can effectively inhibit spore germination, as well as mycelial growth and sporulation. It is mainly used to control oomycete diseases, such as grape downy mildew, potato and tomato late blight, and cucurbit downy mildew.

[0004] Cymoxanil is a highly effective, low-toxicity fungicide. Its mechanism of action and characteristics primarily involve inhibiting the germination of pathogenic fungal spores, and it also has a killing effect on pathogens invading the host. It has protective, curative, and systemic effects, and is effective against fungi in the order Peronomycetes, such as those in the genera *Pyromellita*, *Peronospora*, and *Monopoda*. Cymoxanil has a short effective period when used alone, but its effectiveness can be extended when mixed with protective fungicides. Suitable crops include cucumber, grape, pepper, potato calyx, and tomato. It controls downy mildew and blight, among other diseases.

[0005] Pesticide oil suspensions are pesticide formulations that use oil as the dispersion medium. They are produced by ultra-finely pulverizing solid pesticide technicals that are insoluble in oil, and then uniformly dispersing them in the oil phase with the help of surfactants and stabilizers to form a stable suspension system. Using oil as the medium avoids the use of large amounts of organic solvents (such as toluene and xylene) found in emulsifiable concentrates, significantly reducing flammability, explosiveness, and environmental pollution. Furthermore, there is no dust generation during production and use, reducing the risk of toxicity to operators and the surrounding environment. Compared to water suspensions, wettable powders, and water-dispersible granules, they offer advantages such as better penetration, stronger adhesion, resistance to evaporation and rain erosion, longer residual effect, better efficacy, and better storage stability.

[0006] However, oil suspension formulations have poor stability over time, and the products are prone to stratification and crusting. Common thickeners for oil suspensions are fumed silica and organo-bentonite; however, studies have found that excessive fumed silica can easily lead to paste formation. Organo-bentonite achieves its expandable thickening properties in oil through long-chain quaternary ammonium salt intercalation, but its cationic nature makes it prone to precipitating with conventional emulsifiers like calcium salts, thus losing its thickening effect. Furthermore, after preparation and drying under aqueous conditions, the final product will contain a certain amount of water, which also increases the risk of thixotropy and even paste formation in the oil suspension. High solids content also leads to a sharp increase in system viscosity, making the material extremely thick during sand milling and difficult to discharge.

[0007] Currently, there is a lack of fungicides containing a combination of dimethomorph and cymoxanil that have excellent long-term stability and significant control effects. Summary of the Invention

[0008] Purpose of the invention The purpose of this invention is to provide a dispersible oil suspension for controlling potato late blight, its preparation method, and its application. This invention, when processing a binary compound fungicidal composition of dimethomorph and cymoxanil into a dispersible oil suspension formulation, found that it significantly improves the application efficacy for controlling potato late blight compared to existing formulations.

[0009] Solution In a first aspect, to achieve the objective of the present invention, the present invention provides a dispersible oil suspension for preventing and controlling potato late blight, characterized in that it comprises the following raw materials in weight fractions: 5-25% dimethomorph, 5-25% cymoxanil, 5-20% dispersant, 5-20% emulsifier, 2-5% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#.

[0010] Further, the raw materials include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 10-20% dispersant, 5-20% emulsifier, 2-5% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#; Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 10-16% dispersant, 10-20% emulsifier, 2-5% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 10-16% dispersant, 10-20% emulsifier, 3% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the solvent oil 200# can be replenished to 100%.

[0011] Further, the raw materials include the following weight fractions: the dispersant is selected from one or more of the following: dispersant Soprophor FD, dispersant SP-27001, dispersant SC-29, dispersant 4916, dispersant SP-21SM, dispersant SP-50SM, dispersant SP-1161, and dispersant AG540; optionally, the dispersant includes dispersant 4916 and dispersant SC-29 in a weight ratio of 1:1.6~2, and optionally in a weight ratio of 3:5; And / or, the emulsifier is selected from one or more of alkylphenol polyoxyethylene ether formaldehyde condensate sulfate, alkylphenol polyoxyethylene ether phosphate alkyl sulfate, alkyl sulfonate, naphthalene sulfonate, TERSPERSE 2500, and SP-OD400.

[0012] Further, the raw materials include the following weight fractions: dimethomorph 5-22%, cymoxanil 5-22%, dispersant 4916 4-6%, dispersant SC-29 8-10%, emulsifier SP-OD400 5-20%, sodium carboxymethyl cellulose 2-5%, and solvent oil 200# 27-65%; Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 4-6% dispersant 4916, 8-10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 20-22% dimethomorph, 20-22% cymoxanil, 5-6% dispersant 4916, 8-10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and 27-32% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 22% dimethomorph, 22% cymoxanil, 5-6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and solvent oil 200# to make up to 100%.

[0013] Further, the raw materials include the following weight fractions: 22% dimethomorph, 22% cymoxanil, 66% dispersant 491, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and solvent oil 200# to make up to 100%.

[0014] Furthermore, the weight ratio of dimethomorph to cymoxanil is 1:0.5~2, optionally 1:1.

[0015] Furthermore, it also includes other dosage form excipients, optionally including the following raw materials in weight fractions: antifreeze 0-10%, defoamer 0-0.15%.

[0016] In a second aspect, a dispersible oil suspension as described in the first aspect is provided, characterized by comprising the following steps: mixing diacetyl amide, cymoxanil, dispersant, emulsifier, sodium carboxymethyl cellulose and solvent oil 200#, shearing, and milling to obtain the dispersible oil suspension.

[0017] Thirdly, the application of the dispersible oil suspension agent described in the first aspect or the dispersible oil suspension agent prepared by the preparation method described in the second aspect in the prevention and control of plant diseases is provided. Optionally, the plant disease includes potato late blight.

[0018] Fourthly, a method for using the dispersible oil suspension agent described in the first aspect or the dispersible oil suspension agent prepared by the preparation method described in the second aspect is provided, which involves spraying the agent onto the soil around the roots of the crop at the early stage of crop disease. The application method is a conventional application method for agricultural chemicals, such as irrigation, spraying, or misting. Optionally, the formulation is diluted with water and then sprayed. Optionally, the dosage of the formulation is 20-40 g / mu, or optionally 35 g / mu.

[0019] Beneficial effects: The dispersible oil suspension for controlling potato late blight described in this invention has been shown in field control experiments to be effective in controlling potato late blight, with significant and safe control effects, and no adverse effects on other pests and diseases or on non-target organisms. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprising of," etc., will be understood to include the stated elements or components, and does not exclude other elements or other components.

[0021] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In some embodiments, materials, elements, methods, and means well known to those skilled in the art are not described in detail in order to highlight the spirit of the invention.

[0022] The technical grade of dimethomorph and cymoxanil in the following examples can be obtained commercially, and other raw materials are conventional commercial products. For example, dispersant 4916 was purchased from Croda Chemicals (Shanghai) Co., Ltd., dispersant SC-29 was purchased from Jiangsu Qingyu Chemical Technology Co., Ltd., and emulsifier SP-OD400 was purchased from Jiangsu Qingyu Chemical Technology Co., Ltd.

[0023] Example 1 Add 5% dimethomorph, 5% cymoxanil, 4% dispersant 4916, 8% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and 200# solvent oil to a mixing tank in sequence and mix. First, coarsely crush and homogenize the mixture using a shearing machine, and then pump it into a sand mill for sand milling. Use a particle size analyzer to detect the particle size of the sand-milled material. When the particle size D90 is less than 5 micrometers, a 10% dimethomorph·cymoxanil dispersible oil suspension can be obtained.

[0024] Example 2 10% of dimethomorph, 10% of cymoxanil, 5% of dispersant 4916, 9% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of sodium carboxymethyl cellulose, and 200# solvent oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized using a shear mill, and then fed into a sand mill for grinding. The particle size of the ground material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 20% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0025] Example 3 20% of dimethomorph, 20% of cymoxanil, 5% of dispersant 4916, 10% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of sodium carboxymethyl cellulose, and 200# solvent oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized using a shear mill, and then fed into a sand mill for grinding. The particle size of the ground material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 40% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0026] Example 4 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and solvent oil 200# were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized by a shearing machine, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0027] Example 5 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and methyl oleate to 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized by a shearing machine, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0028] Example 6 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and methylated soybean oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized using a shear mill, and then fed into a sand mill for grinding. The particle size of the ground material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0029] Comparative Example 1 Mix 22% of dimethomorph, 22% of cymoxanil, 4% of polycarboxylate, 2% of sulfonate wetting agent, 5% of glycerol, 0.1% of xanthan gum, 40-60% of the total amount of silicone defoamer (trade name: FTRT AT1501, in the formula), and 60-80% of the total amount of water. Add the mixture to a shearing machine for shearing, and then grind it with a sand mill until the particle size is ≤6 micrometers. Then add 40-60% of the defoamer and the remaining water, stir and disperse evenly to obtain 44% dimethomorph·cymoxanil aqueous suspension.

[0030] Comparative Example 2 A 44% dimethomorph·cymoxanil wettable powder is obtained by thoroughly mixing 22% dimethomorph, 22% cymoxanil, 6% sodium dodecyl sulfate, 6% sodium lignosulfonate, and kaolin to a final concentration of 100%, followed by ultra-fine pulverization.

[0031] Comparative Example 3 22% dimethomorph, 22% cymoxanil, 4% sodium dodecyl sulfate, 5% sodium lignosulfonate, 4% ammonium sulfate, and kaolin to make up to 100% are thoroughly mixed together, ultra-finely pulverized, and then a mixture of appropriate amount of water and binder is added. After granulation by fluidized bed granulation or extrusion granulation and drying, 44% dimethomorph·cymoxanil water-dispersible granules can be obtained.

[0032] Comparative Example 4 22% dimethomorph, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and methylated soybean oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized under high shear to homogenize it, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 22% dimethomorph dispersible oil suspension was obtained.

[0033] Comparative Example 5 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and methylated soybean oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized under high shear, and then fed into a sand mill for grinding. The particle size of the ground material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 22% cymoxanil dispersible oil suspension was obtained.

[0034] Comparative Example 6 22% of dimethomorph, 22% of cymoxanil, 6% of dispersant 4916, 10% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of organobentonite, and methyl oleate to 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized under high shear, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0035] Comparative Example 7 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% organic bentonite, and 200# solvent oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized using a shear mill, and then fed into a sand mill for grinding. The particle size of the ground material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0036] Comparative Example 8 22% of dimethomorph, 22% of cymoxanil, 6% of dispersant 4916, 10% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of organic bentonite, and methylated soybean oil to a final volume of 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized under high shear and homogenized, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was measured using a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0037] Comparative Example 9 22% of dimethomorph, 22% of cymoxanil, 6% of dispersant 4916, 10% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of silica, and methyl oleate to 100% were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized under high shear, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0038] Comparative Example 10 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% silica, and 200# solvent oil were added sequentially to a mixing tank and mixed. The mixture was first coarsely pulverized and homogenized under high shear, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension was obtained.

[0039] Comparative Example 11 22% of dimethomorph, 22% of cymoxanil, 6% of dispersant 4916, 10% of dispersant SC-29, 10% of emulsifier SP-OD400, 3% of silica, and methylated soybean oil were added to a mixing tank to make up to 100%. The mixture was first coarsely pulverized and homogenized under high shear, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a 44% dimethomorph·cymoxanil dispersible oil suspension could be obtained.

[0040] Comparative Example 12: Blank Control Dispersant 4916 6%, dispersant SC-29 10%, emulsifier SP-OD400 10%, sodium carboxymethyl cellulose 3%, and solvent oil 200# to make up to 100% were added to a mixing tank in sequence and mixed. The mixture was first coarsely pulverized and homogenized by high shear, and then pumped into a sand mill for sand milling. The particle size of the sand-milled material was detected by a particle size analyzer. When the particle size D90 was less than 5 micrometers, a blank control could be obtained.

[0041] Test Example 1 The dispersible oil suspensions prepared in Examples 1-6 and Comparative Examples 4-11 were subjected to the following tests: Suspension rate determination Refer to the method specifically for suspension concentrates in GB / T 14825-2023 "Determination of Suspension Rate of Pesticides".

[0042] Low temperature stability test The test was conducted according to GB / T 19137-2003, the method for determining the low-temperature stability of pesticides. The formulation was placed at (0±2)℃ for 1 hour, and the appearance was observed for any changes. The test was continued at (0±2)℃ for 7 days. After 7 days, the formulation was removed and allowed to return to room temperature for observation. The qualified low-temperature indicators were: no layering, solidification or clumping of liquid formulations, and uniform and flowable emulsions.

[0043] Thermal storage stability determination The test was conducted according to GB / T 19136-2021, the method for determining the thermal storage stability of pesticides. The formulation was placed at (54±2)℃ for 14 days. The qualified indicators for thermal storage were: no layering or solidification of liquid formulations, and uniform and flowable emulsions.

[0044] Room temperature stability test The method is the same as that used for determining the stability of thermal storage, except that the temperature is adjusted to room temperature ((25±2)℃).

[0045] The results are shown in Table 1.

[0046] Table 1. Physical properties of Examples 1-6 and Comparative Examples 4-11

[0047] As shown in Table 1, the embodiments provided by this invention, through the screening of dispersion media and thickeners, achieved significantly better thermal storage stability, low-temperature stability, and room-temperature stability than the comparative examples. Specifically, the comparison between Examples 4 and Examples 5 and 6 demonstrates that the selection of solvent oil 200# allows the high-content dispersible oil suspension to achieve better long-term stability while also ensuring excellent suspension rate.

[0048] Test Example 2, Field Trial According to the regulations of the Institute for Drug Control, "GB / T 17980.34-2000 Field Efficacy Test Guidelines for Pesticides (I) - Control of Potato Late Blight with Fungicides", the plot treatments for the test agent, control agent, and blank control were arranged in a randomized block design, with a plot area of ​​10m². 2Apply the pesticide at the initial stage of disease on the plant, and investigate the leaf disease incidence and disease index 14 days later. For each experimental plot, five diagonal sampling points are used, with 2-3 plants sampled at each point. All leaves of each plant are examined, and the disease severity is recorded.

[0049] The disease grading standards are as follows: Grade 0: No lesions; Grade 1: The area of ​​lesions accounts for less than 5% of the total leaf area; Grade 3: The area of ​​lesions accounts for 6%-10% of the total leaf area; Level 5: The area of ​​lesions accounts for 11%-20% of the total leaf area; Level 7: The area of ​​lesions accounts for 21%-50% of the total leaf area; Level 9: The area of ​​lesions accounts for more than 50% of the total leaf area.

[0050] The method for calculating drug efficacy is as follows:

[0051] Based on the survey results, the disease index and prevention efficacy were calculated using the following formula:

[0052]

[0053] The test results are detailed in Table 2.

[0054] Table 2. Concentration settings of tested pesticides and control results (%)

[0055] As shown in Table 2, the dispersible oil suspension of the present invention has excellent control effect against potato late blight, and the dispersible oil suspension prepared in Example 4 has the best control effect. Furthermore, a comparison of the examples and comparative examples in Table 2 reveals that the dispersible oil suspension of the present invention has a better control effect than other formulations. Moreover, the crop grew normally throughout the entire experiment, and no phytotoxicity was observed.

[0056] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0057] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content of the present invention.

Claims

1. A dispersible oil suspension for controlling potato late blight, characterized in that, The raw materials include the following weight fractions: 5-25% dimethomorph, 5-25% cymoxanil, 5-20% dispersant, 5-20% emulsifier, 2-5% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#.

2. The dispersible oil suspension according to claim 1, characterized in that, The raw materials include the following weight fractions: dimethomorph 5-22%, cymoxanil 5-22%, dispersant 10-20%, emulsifier 5-20%, sodium carboxymethyl cellulose 2-5%, and solvent oil 200# 27-65%; Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 10-16% dispersant, 10-20% emulsifier, 2-5% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 10-16% dispersant, 10-20% emulsifier, 3% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the solvent oil 200# can be replenished to 100%.

3. The dispersible oil suspension according to claim 1 or 2, characterized in that, The raw materials include the following weight fractions: the dispersant is selected from one or more of the following: Soprophor FD, SP-27001, SC-29, 4916, SP-21SM, SP-50SM, SP-1161, and AG540; optionally, the dispersant includes dispersant 4916 and dispersant SC-29 in a weight ratio of 1:1.6~2, and optionally in a weight ratio of 3:5; And / or, the emulsifier is selected from one or more of alkylphenol polyoxyethylene ether formaldehyde condensate sulfate, alkylphenol polyoxyethylene ether phosphate alkyl sulfate, alkyl sulfonate, naphthalene sulfonate, TERSPERSE 2500, and SP-OD400.

4. The dispersible oil suspension according to any one of claims 1 to 3, characterized in that, The raw materials include the following weight fractions: dimethomorph 5-22%, cymoxanil 5-22%, dispersant 4916 4-6%, dispersant SC-29 8-10%, emulsifier SP-OD400 5-20%, sodium carboxymethyl cellulose 2-5%, and solvent oil 200# 27-65%; Optionally, the raw materials may include the following weight fractions: 5-22% dimethomorph, 5-22% cymoxanil, 4-6% dispersant 4916, 8-10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and 27-65% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 20-22% dimethomorph, 20-22% cymoxanil, 5-6% dispersant 4916, 8-10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and 27-32% solvent oil 200#. Optionally, the raw materials may include the following weight fractions: 22% dimethomorph, 22% cymoxanil, 5-6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and solvent oil 200# to make up to 100%.

5. The dispersible oil suspension according to any one of claims 1 to 4, characterized in that, The raw materials include the following weight fractions: 22% dimethomorph, 22% cymoxanil, 6% dispersant 4916, 10% dispersant SC-29, 10% emulsifier SP-OD400, 3% sodium carboxymethyl cellulose, and solvent oil 200# to make up to 100%.

6. The dispersible oil suspension according to any one of claims 1 to 5, characterized in that, The weight ratio of dimethomorph to cymoxanil is 1:0.5~2, and optionally 1:

1.

7. The dispersible oil suspension according to any one of claims 1 to 6, characterized in that, It also includes other dosage form excipients, optionally including the following raw materials in weight fractions: antifreeze 0-10%, defoamer 0-0.15%.

8. A dispersible oil suspension according to any one of claims 1 to 6, characterized in that, Includes the following steps: Diyrylamide, cymoxanil, dispersant, emulsifier, sodium carboxymethyl cellulose and solvent oil 200# are mixed, sheared and milled to obtain a dispersible oil suspension.

9. The application of a dispersible oil suspension according to any one of claims 1 to 7 or a dispersible oil suspension prepared by the preparation method according to claim 8 in the prevention and control of plant diseases; Optionally, the plant disease includes potato late blight.

10. A method of using a dispersible oil suspension according to any one of claims 1 to 6 or a dispersible oil suspension prepared by the preparation method according to claim 7 or 8, characterized in that, The step of spraying the soil around the roots of the crop at the early stage of crop disease is to use the conventional application method for agricultural chemicals. Optionally, the formulation can be diluted with water and then sprayed. Optionally, the dosage of the formulation is 20-40g / mu, or 35g / mu.

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