Weeding composition as well as preparation method and application method thereof

Abstract

The invention belongs to the field of pesticides, and particularly relates to a dithiopyr-containing weeding composition as well as a preparation method and an application method thereof. The weeding composition comprises dithiopyr, an organic acid ester, a ketone solvent and a nonionic emulsifier. The weeding composition is low in volatilization rate and free of low-temperature precipitation, and the dispersion stability and the pesticide effect of the weeding composition are effectively improved. In addition, the preparation method of the composition provided by the invention is simple and efficient, convenient to operate and easy to realize large-scale production.

Description

Technical Field

[0001] The invention belongs to the field of pesticides and relates to a herbicide composition, in particular to a herbicide composition containing dithiopyralid and a preparation method and an application method thereof. Background Art

[0002] Dithiopyr, chemical name: S,S′-dimethyl-2-difluoromethyl-4-isobutyl-6-trifluoromethylpyridine-3,5-dithiocarboxate, CAS number: 97886-45-8. Dithiopyr is a pyridine carboxylic acid herbicide used to control weeds in crops and lawns. The herbicide is mainly absorbed through stems, leaves and roots, and inhibits cell division by destroying the formation of spindle microtubules of sensitive weeds. It has good control effects on weeds such as barnyard grass, duckweed, sedge, and knotweed. The physicochemical stability of dithiopyr is affected by the environment. There are obvious differences in volatility and stability under different soil, humidity, temperature and other conditions. Especially under dry and high temperature conditions, the volatilization and decomposition of dithiopyr cause pollution of the ambient atmosphere and soil, and also affect the efficacy of the product. At present, it has been reported that the volatility of dithiopyr can be reduced by coating and preparing capsules, but due to the complicated preparation, poor rapidity and other reasons, it has not been widely commercialized. The melting point of dithiopyridine is 65°C, and the main preparation type is a liquid preparation, which is easy to precipitate crystals at low temperatures, affecting the use and uniformity of the product. In view of this, the present invention is proposed. Summary of the invention

[0003] One of the purposes of the present invention is to provide a herbicidal composition containing dithiopyr, so as to improve the technical problems of the existing dithiopyr liquid preparations such as high volatility, poor dispersion stability and low-temperature precipitation.

[0004] A second object of the present invention is to provide a method for preparing the above-mentioned herbicidal composition.

[0005] A third object of the present invention is to provide a method for applying the above-mentioned herbicidal composition.

[0006] According to the above-mentioned invention object, the present invention provides the following embodiments:

[0007] A herbicidal composition containing dithiopyralid comprises the following components:

[0008] a) dithiopyr;

[0009] b) Organic acid esters;

[0010] c) ketone solvents; and

[0011] d) Nonionic emulsifier.

[0012] Preferably, the organic acid ester is an organic carboxylic acid ester;

[0013] Preferably, the organic carboxylic acid ester is selected from at least one of aromatic carboxylic acid ester and aliphatic carboxylic acid ester;

[0014] Preferably, the aromatic carboxylic acid ester is selected from at least one of C1-C4 alkyl benzoate, methyl o-hydroxybenzoate, methyl phenylacetate, methyl m-toluate, ethyl p-toluate, methyl salicylate, ethyl salicylate, etc.;

[0015] Preferably, the aliphatic carboxylic acid ester is at least one selected from methyl oleate, methyl laurate, ethyl laurate, soybean oil methyl ester, methyl caprate, ethyl caprylate and the like.

[0016] Preferably, the ketone solvent is selected from at least one of N-C1-C8 alkyl pyrrolidone, 4-methyl-1,3-dioxolane-2-one, cyclohexanone, acetophenone, isophorone and the like.

[0017] Preferably, the nonionic emulsifier contains at least one of a polyoxyethylene structure or a polyoxypropylene structure or a polyoxyethylene polyoxypropylene structure; further preferably, the nonionic emulsifier is selected from at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkylphenol polyoxyethylene ether, alkylphenol polyoxypropylene ether, castor oil polyoxyethylene ether, castor oil polyoxypropylene ether, alkyl alcohol polyoxyethylene polyoxypropylene copolymer, alcohol alkoxy compound, polyoxyethylene ether sulfate and polyoxyethylene ether phosphate.

[0018] Preferably, the herbicidal composition further contains other ingredients, and the other ingredients include at least one of other solvents, surfactants, fillers, safeners, and other herbicides.

[0019] Preferably, the mass percentage of dithiopyr in the herbicidal composition is 0.5-40%, more preferably 5-30%, and more preferably 15-25%;

[0020] Preferably, the mass percentage of organic acid esters in the herbicidal composition is 10-50%, more preferably 20-40%;

[0021] Preferably, the mass percentage of the ketone solvent in the herbicidal composition is 5-50%, more preferably 10-30%;

[0022] Preferably, the mass percentage of the nonionic emulsifier in the herbicidal composition is 10-50%, more preferably 15-45%, and even more preferably 15-35%.

[0023] Preferably, the mass percentage of other ingredients in the herbicidal composition is 0-74.5%.

[0024] Preferably, the herbicidal composition is in the form of any one of emulsifiable concentrate (EC), oil dispersant (OD), dispersible concentrate (DC), suspension concentrate (SC), suspoemulsion (SE), microemulsion (ME), and emulsion in water (EW).

[0025] Furthermore, the present invention provides a method for preparing the above-mentioned herbicide composition, comprising the following steps: mixing dithiopyr, organic acid esters, ketone solvents, nonionic emulsifiers and optional other ingredients, and mixing them uniformly by stirring, sand milling or shear emulsification to obtain the herbicide composition.

[0026] Furthermore, the present invention provides a method for applying the above-mentioned herbicidal composition, comprising the following steps: diluting the above-mentioned herbicidal composition into water to form a sprayable solution; and applying the sprayable solution to weeds or the place where they are located.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In the herbicidal composition provided by the present invention, organic acid esters, ketone solvents and nonionic emulsifiers have a significant stabilizing effect on dithiopyralid, which not only reduces the high-temperature volatility of the dithiopyralid formulation product, but also improves the dispersion stability of the product and improves the problem of low-temperature precipitation and crystallization of the dithiopyralid formulation.

[0029] The preparation method of the herbicidal composition provided by the invention has simple process, convenient operation, easy large-scale production and simple product application method. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : Volatility Test 1 result graph of Examples 1-7 and Comparative Examples 1-7.

[0031] Figure 2 : Appearance comparison diagram of volatility test 2 of Examples 5 and 6 and Comparative Examples 5 and 6.

[0032] Figure 3 : Volatility results of volatility test 2 of Examples 5 and 6 and Comparative Examples 5 and 6.

[0033] Figure 4 : Comparison of low temperature stability and dilution stability of Example 6 and Comparative Example 6. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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.

[0035] The first aspect of the present invention provides a herbicidal composition comprising the following components:

[0036] a) dithiopyr;

[0037] b) Organic acid esters;

[0038] c) ketone solvents; and

[0039] d) Nonionic emulsifier.

[0040] In the herbicidal composition provided by the present invention, organic acid esters, ketone solvents and nonionic emulsifiers have a significant stabilizing effect on dithiopyralid, which not only reduces the high-temperature volatility of the dithiopyralid formulation product, but also improves the dispersion stability of the product and improves the problem of low-temperature precipitation and crystallization of the dithiopyralid formulation.

[0041] In some preferred technical solutions, the organic acid ester is an organic carboxylic acid ester, and preferably, the organic carboxylic acid ester is selected from at least one of aromatic carboxylic acid ester and aliphatic carboxylic acid ester;

[0042] Typical but non-limiting aromatic carboxylic acid esters include benzoic acid esters, salicylic acid esters, phenyl acrylate esters, caffeic acid esters, phenylacetic acid esters, naphthylacetic acid esters, etc.;

[0043] Aliphatic carboxylic acid esters such as oleate, acrylate, oxalate, caprate, stearate, adipate, laurate, etc.;

[0044] More preferably, the aromatic carboxylic acid ester is selected from at least one of C1-C4 alkyl benzoate and methyl salicylate, and the aliphatic carboxylic acid ester is methyl oleate.

[0045] In some preferred technical solutions, the ketone solvent is selected from at least one of N-C1-C8 alkyl pyrrolidone and 4-methyl-1,3-dioxolane-2-one.

[0046] In some preferred technical solutions, the nonionic emulsifier is selected from at least one of a polyoxyethylene structure, a polyoxypropylene structure, and a polyoxyethylene-polyoxypropylene structure. Typically but not restrictively, the nonionic emulsifier is selected from at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkylphenol polyoxyethylene ether, alkylphenol polyoxypropylene ether, castor oil polyoxyethylene ether, castor oil polyoxypropylene ether, alkyl alcohol polyoxyethylene-polyoxypropylene copolymer, alcohol alkoxy compound, polyoxyethylene ether sulfate, or polyoxyethylene ether phosphate.

[0047] In some preferred technical solutions, the herbicidal composition further comprises other ingredients, and the other ingredients include at least one of other solvents, surfactants, fillers, safeners, and other herbicides.

[0048] Typically, but not limiting, the other solvent is selected from at least one of aromatic hydrocarbons, vegetable oils, vegetable oil esters, carbonates, and paraffin oils;

[0049] Typically, but not limiting, the surfactant is selected from at least one of carboxylates, sulfonates, sulfates, sulfate esters, phosphates, phosphate esters, fatty alcohol polyoxyethylene ethers, fatty acid polyoxyethylene esters, alkylphenol polyoxyethylene ethers, castor oil polyoxyethylene ethers, ethylene oxide propylene oxide copolymers, alcohol alkoxy compounds, and alkyl acrylates. By adding a surfactant to the herbicidal composition, the herbicidal composition is dispersed in water to form a sprayable solution for application.

[0050] Typically, but not limiting, the filler is selected from at least one of clay, white carbon black, attapulgite, kaolin, diatomaceous earth, starch, and calcium carbonate.

[0051] Typically, but not limiting, the safener is selected from at least one of clofonet-mexyl, fenthiocarb, fenthiocarb, mefenpyr, isoxadiazole, and acids, salts or derivatives thereof.

[0052] In the present invention, other herbicides refer to herbicides other than dithiopyr. Typically but not limiting, the other herbicides are selected from at least one of sulfonylurea herbicides, acetanilide herbicides, aromatic carboxylic acid herbicides, pyridone herbicides, tripyrimidine herbicides, cyclohexanedione oxime herbicides, triazolinone herbicides, and phthalimide herbicides.

[0053] In some preferred technical solutions, when the mass percentage of dithiopyr in the herbicidal composition is 0.5-40%, the herbicidal composition has excellent chemical stability, more preferably 5-30%, and more preferably 15-25%.

[0054] In some preferred technical schemes, the mass percentage of fluthiopyral in the herbicidal composition can be selected from 0.5%, 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, but is not limited thereto.

[0055] In some preferred technical schemes, when the mass percentage of organic acid esters in the herbicidal composition is 10-50% and the mass percentage of ketone solvents is 5-50%, the volatility of fluthiopyr can be effectively reduced. More preferably, when the mass percentage of organic acid esters is 20-40% and the mass percentage of ketone solvents is 10-30%, the stability of the obtained fluthiopyr herbicidal composition is more significant.

[0056] In some preferred technical solutions, the mass percentage of the organic acid ester in the herbicidal composition can be selected from 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, but is not limited thereto.

[0057] In some preferred technical schemes, the mass percentage of ketone solvent in the herbicidal composition can be selected from 10%, 14.5%, 15%, 16%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, but is not limited thereto.

[0058] In some preferred technical solutions, the mass percentage of the nonionic emulsifier in the herbicidal composition can be selected from 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, but is not limited thereto.

[0059] In some preferred technical schemes, the formulation of the herbicidal composition is any one of emulsifiable concentrate (EC), oil dispersant (OD), dispersible liquid (DC), suspension concentrate (SC), suspoemulsion (SE), microemulsion (ME), and emulsion in water (EW).

[0060] According to a second aspect of the present invention, the present invention provides a method for preparing a herbicidal composition, which is carried out according to the following steps: mixing dithiopyr, organic acid esters, ketone solvents, nonionic emulsifiers and optional other solvents, surfactants, fillers, safeners or other herbicides, and mixing them uniformly by stirring, sand milling or shear emulsification to obtain a herbicidal composition.

[0061] The preparation method of the herbicidal composition provided by the invention has simple process, convenient operation, easy large-scale production and simple product application method.

[0062] According to the third aspect of the present invention, the present invention provides a method for applying the above-mentioned herbicidal composition, which is carried out according to the following steps: diluting the above-mentioned herbicidal composition with water to form a sprayable solution, and applying the sprayable solution to the weeds or the place where they are located.

[0063] In order to facilitate those skilled in the art to understand the technical solution, the technical solution provided by the present invention is further described below in conjunction with the embodiments and comparative examples. The contents in the embodiments and comparative examples are all weight percentages.

[0064] The specifications and sources of the raw materials used in the examples and comparative examples are shown in Table 1 below. The raw materials not listed in Table 1 were purchased from the market.

[0065] Table 1

[0066]

[0067] Example 1

[0068] This embodiment provides a herbicide liquid preparation, and the components are expressed in percentage by mass, and the specific composition is as follows: 0.5% dithiopyr, 50% butyl benzoate, 14.5% N-methylpyrrolidone, 30% Emulsogen TS160, and 5% calcium dodecylbenzenesulfonate.

[0069] Example 2

[0070] This embodiment provides a herbicide liquid preparation, and the components are expressed in percentage by mass, and the specific composition is as follows: 10% dithiopyr, 10% methyl oleate, 50% N-octyl pyrrolidone, 20% Emulsogen EL 360, and 10% ETHYLAN NS-500LQ.

[0071] Example 3

[0072] This embodiment provides a herbicide liquid preparation, and the components are expressed in percentage by mass, and the specific composition is as follows: 15% of dithiopyr, 30% of methyl benzoate, 10% of N-octyl pyrrolidone, 25% of Emulsogen TS160, 10% of Atlas G5000, and 10% of Genapol X 060.

[0073] Example 4

[0074] This embodiment provides a herbicide liquid preparation, and the components are calculated by mass percentage, and the specific composition is as follows: 24% of dithiopyr, 30% of methyl salicylate, 16% of N-ethylpyrrolidone, 15% of Emulsogen TS160, 10% of Atlas G5000, and 5% of calcium dodecylbenzenesulfonate.

[0075] Example 5

[0076] This embodiment provides a herbicide liquid preparation, and the components are calculated by mass percentage, and the specific composition is as follows: 24% of fluthiopyr, 40% of methyl salicylate, 16% of 4-methyl-1,3-dioxolane-2-one, 16% of Synperonic 13 / 12, and 4% of calcium dodecylbenzenesulfonate.

[0077] Example 6

[0078] This embodiment provides a herbicide liquid preparation, and the components are expressed in percentage by mass, and the specific composition is as follows: 24% dithiopyr, 30% methyl benzoate, 16% N-octyl pyrrolidone, 10% Emulsogen TS160, 15% Genapol X 080, and 5% calcium dodecylbenzenesulfonate.

[0079] Example 7

[0080] This embodiment provides a herbicide liquid preparation, and the components are expressed in percentage by mass, and the specific composition is as follows: 40% dithiopyr, 30% methyl benzoate, 15% N-butylpyrrolidone, 6% Emulsogen TS160, 4% Atlas G5000, and 5% calcium dodecylbenzenesulfonate.

[0081] The liquid herbicidal composition provided in the above Examples 1-7 is prepared according to the following steps: dithiopyr, organic acid ester, ketone solvent and emulsifier are mixed and stirred uniformly at 50° C. according to the composition ratio, and cooled to room temperature to obtain the liquid herbicidal composition.

[0082] Comparative Example 1

[0083] This comparative example provides a herbicide liquid preparation, which is different from Example 1 in that Emulsogen TS160 is replaced by water, and the remaining raw materials and contents are the same as those in Example 1.

[0084] Comparative Example 2

[0085] This comparative example provides a herbicide liquid preparation, which is different from Example 2 in that N-octyl pyrrolidone is replaced with Solvesso 150 (aromatic hydrocarbon), and the remaining raw materials and contents are the same as those in Example 2.

[0086] Comparative Example 3

[0087] This comparative example provides a herbicide liquid preparation, which is different from Example 3 in that methyl benzoate is replaced by ARMID DM10 (alkyl amide), and the remaining raw materials and contents are the same as those in Example 3.

[0088] Comparative Example 4

[0089] This comparative example provides a herbicide liquid preparation, which is different from Example 4 in that methyl salicylate is replaced by tetrahydrofurfuryl alcohol, and the remaining raw materials and contents are the same as those in Example 4.

[0090] Comparative Example 5

[0091] This comparative example provides a herbicide liquid preparation, which is different from Example 5 in that 4-methyl-1,3-dioxolane-2-one is replaced by ARMID DM10 (alkyl amide), and the remaining raw materials and contents are the same as those in Example 5.

[0092] Comparative Example 6

[0093] This comparative example provides a herbicidal liquid preparation, which is a commercially available product of DOW, "Dimension 2EW" dithiopyral preparation, containing 24 wt % of dithiopyral.

[0094] Comparative Example 7

[0095] This comparative example provides a herbicide liquid preparation, and the specific composition of each component, calculated by mass percentage, is as follows: 24% dithiopyr and 76% cyclohexanone.

[0096] The liquid herbicidal composition provided in Comparative Examples 1-5 and Comparative Example 7 is prepared according to the following steps: dithiopyralid, organic acid ester, solvent and emulsifier are mixed and stirred uniformly at 50°C according to the composition ratio, and the liquid herbicidal composition is obtained after cooling to room temperature.

[0097] Volatility Test 1

[0098] The samples of Examples 1-7 and Comparative Examples 1-7 were dripped onto the surface of each glass slide using a pipette. A total of 50 mg of dithiopyr active ingredient was dripped onto each glass slide. Four groups of each sample were repeated. The glass slides were placed in a 60°C forced air oven without a cover. The glass slide samples were collected at 0 hours, 6 hours, 12 hours, and 24 hours of oven volatilization, and the remaining dithiopyr content on the glass slides was detected. The test results are shown in the attached figure. Figure 1 shown.

[0099] Volatility Test 2

[0100] The samples of Examples 5 and 6 and Comparative Examples 5 and 6 were dripped onto the surface of each glass slide using a pipette, and a total of 50 mg of fluthiopyr active ingredient was dripped onto each glass slide, and each sample was repeated in 4 groups. The glass slides were placed in an open and ventilated greenhouse. During the test, the average daily minimum temperature of the greenhouse was 28.5°C, the average daily maximum temperature was 34.3°C, and the average humidity was 82%. The glass slide samples were collected at 0 days, 7 days, 14 days, and 28 days after volatilization at room temperature, and the remaining fluthiopyr content on the glass slides was detected. The volatilization rate was calculated according to the following formula.

[0101]

[0102] The test results are as attached Figure 2 and attached Figure 3 As shown, Figure 2 The following are appearance comparison diagrams of the glass slide samples of each embodiment and comparative example after being placed at room temperature for 14 days. It can be seen that the samples of comparative examples 5 and 6 precipitate white crystals, while the samples of embodiments 5 and 6 are still in a droplet state. Figure 3 It is the volatility result diagram of each embodiment and comparative example.

[0103] Stability test

[0104] The stability of the preparations provided in the examples and comparative examples was analyzed under different conditions. After being stored at 0 and -16°C for 7 days, the appearance of these liquid preparations was observed. When the temperature was controlled at 10°C, these preparations were diluted to 1% dilutions, and the appearance and dispersion stability of the dilutions were observed after 24 hours. The results are shown in Table 2 below. The low temperature stability and dilution stability of Example 6 and Comparative Example 6 are shown in the attached Table 2. Figure 4 As shown, Example 6 is a uniform liquid without crystallization under low-temperature cold storage and dilution; Comparative Example 6 has large white crystals precipitated at the bottom after low-temperature cold storage, and is unevenly dispersed after dilution with 10°C water, with a large amount of needle-shaped crystalline solids suspended at the bottom, presenting a turbid state.

[0105] Table 2

[0106] Store at 0℃ for 7 days Store at -16℃ for 7 days 1% dilution stability (10℃) Example 1 Transparent liquid Homogeneous liquid No precipitation Example 2 Transparent liquid Homogeneous liquid No precipitation Example 3 Transparent liquid Homogeneous liquid No precipitation Example 4 Transparent liquid Homogeneous liquid No precipitation Example 5 Transparent liquid Homogeneous liquid No precipitation Example 6 Transparent liquid Homogeneous liquid No precipitation Example 7 Transparent liquid Turbid liquid No precipitation Comparative Example 1 Transparent liquid Transparent liquid Crystal precipitation Comparative Example 2 Transparent liquid Turbid liquid Crystal precipitation Comparative Example 3 Transparent liquid Turbid liquid No precipitation Comparative Example 4 turbid Crystallization Crystal precipitation Comparative Example 5 Transparent liquid Turbid liquid No precipitation Comparative Example 6 turbid Crystallization Crystal precipitation Comparative Example 7 Transparent liquid Crystallization Crystal precipitation

[0107] Bio-test

[0108] The following test was conducted to determine the herbicidal activity of the liquid formulations provided in Examples 3-6 of the present invention and the liquid formulations provided in Comparative Examples 3-6. The test results are shown in Table 3 below.

[0109] The specific steps of the test are as follows:

[0110] A greenhouse pot test was conducted. The test soil was a mixture of laboratory clay and seedling medium in a volume ratio of 1:2. A flower pot with a diameter of 6.5 cm and a depth of 5.5 cm was taken and filled with soil to 3 / 4 of the height. After adding water to make the soil completely moist, an equal amount of test weed seeds (barnyard grass) was sown in the flower pot. After sowing, the soil was covered with about 0.2 cm of soil. The soil was saturated with water by adding water from the bottom and then placed in a greenhouse for cultivation and growth. The soil moisture was maintained. The greenhouse temperature was maintained at 20℃~30℃, the air humidity was above 60%, and the greenhouse was kept ventilated. The soil was sprayed 24 hours after sowing. The pesticide treatment was prepared according to the designed dosage and then placed in a walking spray tower (HCL-2000) for spraying. Each weed was repeated 4 times, the spray height was 50 cm, the spray pressure was 0.2 MPa, the spray water volume was 600 L / ha, and the application dosages of the dithiopyr liquid preparation samples were 108 g ai / ha and 144 g ai / ha, respectively. 14 days after the application of the drug, the comprehensive growth inhibition rate (%) was investigated by visual inspection. 28 days after the application of the drug, the fresh weight of the aboveground part of each treatment was measured, and the fresh weight inhibition rate (%) was calculated according to the formula.

[0111]

[0112] Table 3

[0113]

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A herbicidal composition containing dithiopyr, characterized in that: The herbicidal composition comprises a) dithiopyr; b) Organic acid esters; c) ketone solvents; and d) Nonionic emulsifier.

2. The herbicidal composition according to claim 1, characterized in that The volatilization rate of dithiopyralid of the herbicidal composition after volatilization at 60° C. for 24 hours is less than 30%.

3. The herbicidal composition according to claim 1, characterized in that The organic acid ester is an organic carboxylic acid ester; preferably, the organic carboxylic acid ester is selected from at least one of aromatic carboxylic acid ester and aliphatic carboxylic acid ester; further preferably, the aromatic carboxylic acid ester is selected from at least one of benzoic acid C1-C4 alkyl ester or methyl salicylate, and the aliphatic carboxylic acid ester is methyl oleate; Preferably, the ketone solvent is selected from at least one of N-C1-C8 alkyl pyrrolidone and 4-methyl-1,3-dioxolane-2-one.

4. The herbicidal composition according to claim 1, characterized in that The nonionic emulsifier contains a polyoxyethylene structure, a polyoxypropylene structure or a polyoxyethylene-polyoxypropylene structure.

5. The herbicidal composition according to claim 1, characterized in that The herbicidal composition further contains other ingredients; the other ingredients include at least one of other solvents, surfactants, fillers, safeners, and other herbicides; Preferably, the surfactant is selected from at least one of carboxylates, sulfonates, sulfates, sulfate esters, phosphates, phosphate esters, fatty alcohol polyoxyethylene ethers, fatty acid polyoxyethylene esters, alkylphenol polyoxyethylene ethers, castor oil polyoxyethylene ethers, ethylene oxide propylene oxide copolymers, alcohol alkoxy compounds, and alkyl acrylates; preferably, the surfactant is a sulfonate.

6. The herbicidal composition according to claim 1, characterized in that In terms of mass percentage, the herbicidal composition comprises 0.5-40% dithiopyr, 10-50% organic acid esters, 5-50% ketone solvent, 10-50% nonionic emulsifier; Preferably, comprising 5-30% dithiopyr, 20-40% organic acid esters, 10-30% ketone solvent, 15-45% nonionic emulsifier.

7. The herbicidal composition according to any one of claims 1 to 6, characterized in that The herbicidal composition is in the form of any one of emulsifiable concentrate, oil dispersant, dispersible liquid, suspension, suspoemulsion, microemulsion and aqueous emulsion.

8. The method for preparing the herbicidal composition according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: mixing dithiopyr, organic acid esters, ketone solvents, nonionic emulsifiers and other components, and mixing them uniformly by stirring, sand milling or shearing emulsification to obtain a herbicidal composition.

9. The method for applying the herbicidal composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: The herbicidal composition according to any one of claims 1 to 6 is diluted in water to form a sprayable solution, and the sprayable solution is applied to weeds or the location thereof.

10. A method for reducing the volatility of dithiopyr, characterized in that: The method comprises the step of mixing and contacting the dithiopyr with an organic acid esterified compound, a ketone solvent and a nonionic emulsifier in an effective amount to reduce volatility.

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