A herbicidal composition and use thereof

Abstract

This invention belongs to the field of pesticide weeding technology, and discloses a weeding composition and its application. The weeding composition comprises active ingredient A and active ingredient B. Active ingredient A is isoxaflutole or isoxaflutole methyl ester, and active ingredient B is any one of pyrimethanil, pyrimifluridine, or bispyribac-sodium. The mass ratio of active ingredient A to active ingredient B is 1:6 to 12:1. The weeding composition of this invention has a significant synergistic effect on weeds in paddy fields.

Description

Technical Field

[0001] This invention belongs to the field of pesticide weeding technology, and discloses a weeding composition and its application. Background Technology

[0002] Weeds in paddy fields compete with rice for nutrients, space, and sunlight, negatively impacting rice growth and development and hindering high yields and quality. Therefore, weed control is crucial for ensuring rice production and quality. Currently, weed control remains primarily chemical, but continuous use of herbicides with single mechanisms of action is leading to increasing herbicide resistance in weeds. Therefore, screening for highly efficient, safe, and labor-saving herbicides is of great importance. Summary of the Invention

[0003] Based on the above, this invention provides a herbicidal composition that effectively controls various types of common weeds in rice paddies, including grasses, broadleaf weeds, and sedges, and is highly safe for rice and does not cause phytotoxicity to subsequent crops. It can be used for integrated management of resistant weeds in rice paddies.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a herbicidal composition comprising active ingredient A and active ingredient B, wherein active ingredient A is isoxaflutole or isoxaflutole methyl ester, and active ingredient B is any one of pyrimethanil, pyrimimethoxam, or bispyribac-sodium; the mass ratio of active ingredient A to active ingredient B is 1:6 to 12:1, or any value within the above range.

[0005] Furthermore, the mass ratio of isoxaflutole to pyrimethanil is 1:5 to 9:1, or any value within the above range;

[0006] The mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:6 to 6:1, or any value within the above range.

[0007] The mass ratio of isoxaflutole to pyrimidine oxime is 1:6 to 6:1, or any value within the above range;

[0008] The mass ratio of isoxaflutole methyl ester to pyrimimethoxam is 1:5 to 6:1, or any value within the above range.

[0009] The mass ratio of isoxaflutole to bispyribac-sodium is 1:6 to 12:1, or any value within the above range.

[0010] The mass ratio of isoxaflutole methyl ester to bispyribac-sodium is 1:6 to 9:1, or any value within the above range.

[0011] Furthermore, the mass ratio of isoxaflutole to pyrimethanil is 1:4 to 9:1, or any value within the above range;

[0012] The mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:4 to 6:1, or any value within the above range.

[0013] The mass ratio of isoxaflutole to pyrimidine oxime is 1:5 to 9:2, or any value within the above range;

[0014] The mass ratio of isoxaflutole methyl ester to pyrimimethoxam is 1:5 to 6:1, or any value within the above range.

[0015] The mass ratio of isoxaflutole to bispyribac-sodium is 1:6 to 9:1, or any value within the above range.

[0016] The mass ratio of isoxaflutole methyl ester to bispyribac-sodium is 1:6 to 6:1, or any value within the above range.

[0017] Furthermore, in the herbicidal composition, active ingredient A and active ingredient B account for 1% to 80% of the total weight of the herbicidal composition, or any value within the above range, based on 100 wt%.

[0018] Furthermore, the herbicidal composition contains other auxiliary ingredients in addition to the active ingredients, and the auxiliary ingredients are selected from one or more of the following: wetting agents, dispersants, emulsifiers, thickeners, disintegrants, antifreeze agents, defoamers, solvents, preservatives, stabilizers, synergists, or carriers.

[0019] Furthermore, the herbicidal composition can be prepared into a liquid formulation or a solid formulation.

[0020] Furthermore, the liquid formulation is a suspension, emulsifiable concentrate, dispersible oil suspension, microemulsion, or water emulsion; the solid formulation is a wettable powder, granules, or water-dispersible granules.

[0021] The present invention also discloses the application of the herbicidal composition described above for controlling weeds in rice paddies.

[0022] Furthermore, the weeds are annual weeds, specifically grass weeds, broadleaf weeds, or sedge weeds.

[0023] Furthermore, the grassy weeds are barnyard grass, *Leymus chinensis*, *Echinochloa crus-galli*, *Alopecurus aequalis*, *Digitaria sanguinalis*, and *Eleusine indica*; the broadleaf weeds are *Eclipta prostrata*, *Echinochloa chinensis*, *Alternanthera philoxeroides*, *Monochoria vaginalis*, *Sagittaria sagittifolia*, *Potamogeton crispus*, and *Potamogeton crispus*; and the sedges are *Cyperus difformis*, *Cyperus rotundus*, and *Cyperus rotundus*.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. The herbicidal composition provided by this invention can effectively control weeds in paddy fields and delay the development of herbicide resistance in weeds;

[0026] 2. The herbicidal composition of the present invention broadens the spectrum of weed control, exhibiting excellent activity against grassy weeds, sedges, and broadleaf weeds. Compared with single agents, it has a significant synergistic effect on the control of these weeds, and has a long residual effect, which can reduce the dosage of pesticides, reduce the cost of pesticides, and reduce the impact on the environment. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the formulation preparation examples and specific examples. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The preparation examples prepared below have all met the quality and technical indicators required for the corresponding preparations after testing, and the resulting preparations are qualified preparations recognized in this field.

[0029] Preparation method of formulation example:

[0030] 1. Suspension agent: According to the formula ratio, the active ingredients, surfactants and other functional additives are placed in the reaction vessel in sequence, water is added and mixed evenly, and then subjected to high-speed shearing, wet sand milling and finally homogenization filtration to obtain the suspension agent product.

[0031] 2. Water-dispersible granules: According to the formula ratio, the active ingredients are added to the carrier, and surfactants and other functional additives are added to it. After mixing, the mixture is pulverized by air jet and 10-25% water is added. Then, the mixture is kneaded, granulated, dried and sieved to obtain the water-dispersible granule product; or the pulverized powder is sprayed with water, granulated and dried in a fluidized bed granulator, and then sieved to obtain the product.

[0032] 3. Emulsifiable concentrate: According to the formula ratio, add the active ingredient, solvent, and co-solvent into the mixing tank and stir to dissolve them. Then add the emulsifier, and use the remaining solvent to make up the balance. Stir evenly in the mixing tank, and filter to obtain the emulsifiable concentrate required by the present invention.

[0033] 4. Wettable powder: According to the formula ratio, the active ingredients, dispersant, wetting agent and filler are mixed and stirred evenly in a mixing tank. The mixture is then pulverized and mixed evenly multiple times by an air jet mill to prepare the wettable powder of the composition of the present invention.

[0034] 5. Water-in-water emulsion: Dissolve the active ingredients in the solvent according to the formula ratio, add the emulsifier to form a uniform oil phase, mix deionized water, antifreeze, etc. together to form a uniform aqueous phase; under high-speed shearing, add the oil phase to the aqueous phase, shear until the particle size is qualified, add defoamer, thickener, and preservative and stir evenly to form a well-dispersed water-in-water emulsion product.

[0035] 6. Dispersible oil suspension: According to the formula ratio, the active ingredients, surfactants and other functional additives are placed in the reaction vessel in sequence, mixed evenly with oil, and then subjected to high-speed shearing, wet sand milling and finally homogenized filtration to obtain the dispersible oil suspension product.

[0036] 7. Microemulsion: According to the formula ratio, the active ingredients, solvents, emulsifiers, etc. are mixed evenly to obtain the oil phase. The antifreeze and water are mixed evenly to obtain the aqueous phase. The oil phase is added to the aqueous phase under stirring and stirred evenly. Shearing is continued for 10 minutes. Then, the defoamer is added and stirred evenly to obtain small droplets with oil phase particles of 0.01 to 0.1 micrometers, which is the microemulsion product.

[0037] Preparation Example 1: 28% isoxaflutole·pyrimethanil wettable powder (6:1)

[0038] Formula composition: 24% isoxaflutole, 4% pyrimethanil, 3% sodium polycarboxylate, 2% naphthalenesulfonate formaldehyde condensate, 2.5% bleaching powder BX, 6% silica, and kaolin to make up the balance.

[0039] Preparation Example 2: 24% isoxaflutole·pyrimethanil suspension (3:1)

[0040] Formula composition: 18% isoxaflutole, 6% pyrimethanil, 2% sodium dodecyl sulfate, 2% sodium alkyl polyoxyethylene ether sulfonate, 3% arylphenol polyoxyethylene ether phosphate, 0.25% xanthan gum, 1% magnesium aluminum silicate, 5% ethylene glycol, 0.1% sodium benzoate, 0.5% silicone oil, deionized water to make up the balance.

[0041] Preparation Example 3: 12% Isoxaflutole methyl ester·Pyrazosulfan dispersible oil suspension (1:1)

[0042] Formula composition: 6% isoxaflutole methyl ester, 6% pyrimethanil, 3% lignin sulfonate, 15% castor oil polyoxyethylene ether, 3% phenethylphenol polyoxyethylene polyoxypropylene ether, 3% fatty alcohol polyoxyethylene ether, 2% calcium dodecylbenzene sulfonate, 1% silica, 1% organic bentonite, and soybean oil to make up the balance.

[0043] Preparation Example 4: 16% isoxaflutole methyl ester·pyrimethanil suspension (1:3)

[0044] Formula composition: 4% isoxaflutole methyl ester, 12% pyrimethanil, 2% guerbert alcohol polyoxyethylene ether, 1% fatty alcohol polyoxyethylene ether sodium sulfate, 2% tristyrene phenol ethoxylate phosphate, 2% sorbitan oleate polyoxyethylene ether, 0.25% xanthan gum, 1% magnesium aluminum silicate, 5% ethylene glycol, 0.1% potassium benzoate, 0.5% silicone oil, deionized water to make up the balance.

[0045] Preparation Example 5: 15% isoxaflutole·pyrimidine oxime emulsifiable concentrate (1:2)

[0046] Formula composition: 5% isoxaflutole, 10% pyrimidinoxane, 15% DMF, 15% tristyrene-phenylphenol polyoxyethylene ether polyoxypropylene ether, 3% calcium dodecylbenzenesulfonate, 15% propylene carbonate, xylene to make up the balance.

[0047] Preparation Example 6: 11% Isoxaflutole·Pyrimidine oxime-ether dispersible oil suspension (9:2)

[0048] Formula composition: 9% isoxaflutole, 2% pyrimidinyl oxime, 1% fatty alcohol polyoxyethylene ether, 15% castor oil polyoxyethylene ether, 2% calcium dodecylbenzene sulfonate, 2% succinate sulfonate, 1.5% magnesium aluminum silicate, 1% Tesco 869, corn oil to make up the balance.

[0049] Preparation Example 7: 10% isoxaflutole methyl ester·pyrimidine oxime hydrochloride emulsion (3:2)

[0050] Formula composition: 6% isoxaflutole methyl ester, 4% pyrimidinyl oxime, 4% ethylene glycol oxyethylene polyoxypropylene ether, 2% castor oil polyoxyethylene ether phosphate, 15% cyclohexanone, 5% thiol, 0.1% xanthan gum, 0.2% isothiazolinone, 5% propylene glycol, 1.5% urea, 0.3% sodium sorbate, 0.1% silicone defoamer, deionized water to make up the balance.

[0051] Preparation Example 8: 12% isoxaflutole methyl ester·pyrimidine oxime microemulsion (3:1)

[0052] Formula composition: 9% isoxaflutole methyl ester, 3% pyrimidinoxane, 18% cyclohexanone, 15% tristyrene-phenylphenol polyoxyethylene ether, 3% sorbitan oleate polyoxyethylene ether, 2% sodium fatty alcohol polyoxyethylene ether sulfate, 0.05% silicone defoamer, and deionized water to make up the balance.

[0053] Preparation Example 9: 21% isoxaflutole·bispyribac-sodium suspension (6:1)

[0054] Formula composition: 18% isoxaflutole, 3% bispyribac-sodium, 1% guerbert alcohol polyoxyethylene ether, 2% naphthalene sulfonate formaldehyde condensate, 3% tristyrylphenol polyoxyethylene ether phosphate, 2% isotridecyl alcohol polyoxyethylene ether, 0.25% xanthan gum, 1% magnesium aluminum silicate, 5% propylene glycol, 0.15% potassium benzoate, 0.5% silicone oil, deionized water to make up the balance.

[0055] Preparation Example 10: 28% isoxaflutole·bispyribac-sodium wettable powder (1:3)

[0056] Formula composition: 7% isoxaflutole, 21% bispyribac-sodium, 2% sodium alkyl polyoxyethylene ether sulfonate, 3% alkyl naphthalene sulfonate, 5% sodium polynaphthalene formaldehyde sulfonate, 2% sodium dodecyl sulfate, 10% kaolin, 10% silica, and bentonite to make up the balance.

[0057] Preparation Example 11: 16% isoxaflutole methyl ester·bispyribac-sodium dispersible oil suspension (3:1)

[0058] Formula composition: 12% isoxaflutole methyl ester, 4% bispyribac-sodium, 3% phenylethylphenol polyoxyethylene polyoxypropylene ether, 15% castor oil polyoxyethylene ether, 2% calcium dodecylbenzene sulfonate, 1% sodium polycarboxylate, and soybean oil to make up the balance.

[0059] Preparation Example 12: 24% isoxaflutole methyl ester·bispyribac-sodium water-dispersible granules (1:2)

[0060] Formula composition: 8% isoxaflutole methyl ester, 16% bispyribac-sodium, 8% succinate sulfonate, 5% naphthalene sulfonate formaldehyde condensate, 2% sodium dodecyl sulfate, 30% starch, and kaolin to make up the balance.

[0061] Example 1: Indoor weed control bioactivity test

[0062] Test basis: The test refers to NY / T 1155.5-2006 "Guidelines for Indoor Bioassay Tests of Pesticides - Herbicides Part 5: Soil Activity Test of Herbicides in Paddy Fields - Irrigation Method".

[0063] Experimental targets: barnyard grass, rice barnyard grass, large spike barnyard grass, angelica, rain-dwelling flower, jointed greens, sedge, and rice barnyard grass.

[0064] Test agents: isoxaflutole technical, isoxaflutole methyl ester technical, pyrimethanil technical, pyrimethanil technical, and bispyribac-sodium technical.

[0065] Drug preparation: Dissolve the above raw materials in a suitable solvent, then dilute with 0.1% Tween 80 aqueous solution to prepare single-dose stock solutions, and experimentally design different ratios to prepare the required series of mass concentrations for each single agent and each group of ratio mixtures.

[0066] Experimental Method: 6cm of sterilized fine soil was filled into 15cm diameter, 8cm high black plastic pots. These pots were then placed in plastic trays filled with water, allowing the water to gradually seep in. Once the soil was fully saturated, 30-50 weed seeds were sown in each pot, covered with 0.2-1cm of soil depending on seed size. After sowing, the pots were placed in a greenhouse at 25-30℃ and 65%-85% relative humidity. Spraying was performed when the weeds reached the 4-5 leaf stage. Before application, weak seedlings were thinned to a minimum of 10 seedlings per pot. Based on the preliminary experimental results, the above-mentioned pesticides were sprayed according to the experimental design. A water control treatment was also included. Each treatment was repeated four times. The spraying tool was an ASS-4 automatic control sprayer manufactured by the Beijing Agricultural Information Technology Research Center, with a fan-shaped nozzle and a spray pressure of 275kPa. During spraying, the pots were placed on the sprayer, and the distance between the nozzle and the top of the pot was adjusted to 50cm. The designed dosage was sprayed evenly. After spraying, observe and record the symptoms of weed damage periodically, such as growth inhibition, chlorosis, and deformity. Weigh and record the fresh weight of the above-ground parts of the weeds 14 days after spraying, and calculate the control efficacy by the following formula.

[0067] Calculation method: Fresh weight control efficacy E = (Fresh weight of weeds in control area - Fresh weight of weeds in treatment area) × 100 / Fresh weight of weeds in control area

[0068] The combined effects of the mixtures were determined using the Gowing method, and the calculation formula is as follows:

[0069] Theoretical control efficacy of the mixture E0 = Weed control efficacy of herbicide A at dosage P + Weed control efficacy of herbicide B at dosage Q - Weed control efficacy of herbicide A at dosage P × Weed control efficacy of herbicide B at dosage Q ÷ 100

[0070] Evaluation criteria for the combined effects of mixed drugs:

[0071] E-E0 > 10% indicates a synergistic effect, E-E0 < -10% indicates an antagonistic effect, and E-E0 between ±10% indicates an additive effect.

[0072] Experimental results:

[0073] Table 1. Results of the indoor bioactivity assay of isoxaflutole and pyrimethanil combination on barnyardgrass.

[0074]

[0075]

[0076] Table 1 shows that the combination of isoxaflutole and pyrimethanil at appropriate mass ratios effectively controls barnyardgrass. A mass ratio of isoxaflutole to pyrimethanil of 1:5 to 12:1 results in an E-E0 greater than -10%, indicating an additive or synergistic effect. A mass ratio of isoxaflutole to pyrimethanil of 1:5 to 9:1 also results in an E-E0 greater than 10%, indicating a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole to pyrimethanil is 3:1.

[0077] Table 2 Results of the in vitro bioactivity assay of isoxaflutole and pyrimethanil combination in *Eclipta prostrata*

[0078]

[0079] Table 2 shows that the combination of isoxaflutole methyl ester and pyrimethanil at an appropriate mass ratio has a good control effect on broadleaf weed *Eclipta prostrata*. When the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:5–12:1, the E-E0 is greater than -10%, indicating an additive or synergistic effect. When the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:4–9:1, the E-E0 is greater than 10%, indicating a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:1.

[0080] Table 3. Results of the indoor bioactivity assay of isoxaflutole and pyrimethanil combined on Cyperus difformis.

[0081]

[0082] Table 3 shows that the combination of isoxaflutole and pyrimethanil at appropriate mass ratios effectively controls the sedge weed *Cyperus difformis*. A mass ratio of isoxaflutole to pyrimethanil of 1:5 to 12:1, with an E-E0 greater than -10%, indicates an additive or synergistic effect. A mass ratio of isoxaflutole methyl ester to pyrimethanil of 1:4 to 6:1, with an E-E0 greater than 10%, also indicates a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:3.

[0083] Table 4. Results of the indoor bioactivity assay of isoxaflutole and pyrimiflunomide combination on Rieslingia indica.

[0084]

[0085]

[0086] Table 4 shows the results of the indoor experiments. It is evident that combining isoxaflutole methyl ester and pyrimiflutole at appropriate mass ratios effectively controls the grassy weed *Leersia scoparia*. A mass ratio of isoxaflutole methyl ester to pyrimiflutole of 1:6 to 6:1 results in an E-E0 greater than -10%, indicating an additive or synergistic effect. A mass ratio of isoxaflutole methyl ester to pyrimiflutole of 1:5 to 6:1 also results in an E-E0 greater than 10%, indicating a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole methyl ester to pyrimiflutole is 3:2.

[0087] Table 5. Results of the indoor bioactivity assay of isoxaflutole and pyrimimethoxazole combination on *Heliotropium indicum*.

[0088]

[0089] Table 5 shows the results of the indoor experiments. It is evident that combining isoxaflutole and pyrimiflutole at appropriate mass ratios effectively controls the broadleaf weed *Heliotropium indicum*. A mass ratio of isoxaflutole to pyrimiflutole of 1:6 to 6:1 results in an E-E0 greater than -10%, indicating an additive or synergistic effect. A mass ratio of isoxaflutole to pyrimiflutole of 1:5 to 9:2 also results in an E-E0 greater than 10%, indicating a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole to pyrimiflutole is 1:2.

[0090] Table 6. Results of the indoor bioactivity assay of isoxaflutole and pyrimimethoxam combination on Cyperus difformis.

[0091]

[0092] Table 6 shows the results of the indoor experiments. It is evident that combining isoxaflutole methyl ester and pyrimiflunomide at an appropriate mass ratio effectively controls the sedge weed *Cyperus difformis*. When the mass ratio of isoxaflutole methyl ester to pyrimiflunomide is 1:6 to 6:1, with an E-E0 greater than 10%, a synergistic effect is observed. The synergistic effect is most significant when the mass ratio of isoxaflutole methyl ester to pyrimiflunomide is 3:1.

[0093] Table 7 Results of the indoor bioactivity assay of isoxaflutole and bispyribac-sodium combination on Alopecurus aegyptium

[0094]

[0095]

[0096] Table 7 shows that the combination of isoxaflutole and bispyribac-sodium at an appropriate mass ratio has a good control effect on the grass weed *Alopecurus aequalis*. The mass ratio of isoxaflutole to bispyribac-sodium is 1:6 to 12:1, with an E-E0 greater than 10%, indicating a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole to bispyribac-sodium is 6:1.

[0097] Table 8 Results of indoor bioactivity assay of isoxaflutole and bispyribac-sodium combination on *Gnaphalium affine*

[0098]

[0099] Table 8 shows the results of the indoor experiments. It is evident that combining isoxaflutole methyl ester and bispyribac-sodium at appropriate mass ratios effectively controls the broadleaf weed *Hemiptera chinensis*. When the mass ratio of isoxaflutole methyl ester to bispyribac-sodium is 1:6–12:1, with an E-E0 greater than -10%, it exhibits an additive or synergistic effect. When the mass ratio of isoxaflutole methyl ester to bispyribac-sodium is 1:6–9:1, with an E-E0 greater than 10%, it also exhibits a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole methyl ester to bispyribac-sodium is 3:1.

[0100] Table 9 Results of the indoor bioactivity assay of isoxaflutole and bispyribac-sodium combination on *Symplocos cuspidatum*

[0101]

[0102]

[0103] Table 9 shows the results of the indoor experiments. It is evident that combining isoxaflutole and bispyribac-sodium at appropriate mass ratios effectively controls the sedge weed *Cyperus difformis*. A mass ratio of isoxaflutole to bispyribac-sodium of 1:6 to 12:1, with an E-E0 greater than -10%, indicates an additive or synergistic effect. A mass ratio of isoxaflutole to bispyribac-sodium of 1:6 to 9:1, with an E-E0 greater than 10%, also indicates a synergistic effect. The synergistic effect is most significant when the mass ratio of isoxaflutole to bispyribac-sodium is 1:3.

[0104] Example 2: Field efficacy trial

[0105] Experimental basis: The experiment was conducted in accordance with GB / T 17980.40—2000 Field Efficacy Test Guidelines for Pesticides (I) Herbicides for the Control of Weeds in Rice Fields.

[0106] The experiment was conducted in Wangtaiping Village, Taiping Street, Hedong District, Linyi City, Shandong Province. The experimental site was flat, with uniform fertility, an organic matter content of 1.17%, and a pH value of 6.8. The previous crop was wheat.

[0107] The experimental crop was rice variety Xudao 9, which was growing well.

[0108] Experimental target: Common annual weeds in rice paddies.

[0109] Experimental Methods: The experiment was conducted in mid-July, when rice was at the 4-5 leaf stage and weeds were at the 2-4 leaf stage. One day before application, standing water in the field was drained; one day after application, the field was refilled and the water level was maintained at 3-5 cm for approximately 7 days. The application tool was an HD-400 backpack sprayer manufactured by Singapore Linong Pte Ltd, with a single fan-shaped nozzle and a pressure of 1 kgf / cm². 2 Spray volume 600L / hm 2 All treatments were performed with 4 replicates, and the cell size was 20m². 2 Each area was embanked and irrigated separately, with randomized block arrangements.

[0110] After application, the symptoms of herbicide application in weeds and rice, such as growth inhibition, chlorosis, and malformation, were observed and recorded periodically. Four random sampling points were conducted in each plot at 14 and 28 days post-application, with each point covering 0.25 m. 2 The number of weeds was assessed 14 days after application, and the number and fresh weight of weeds were assessed 28 days after application. The control efficacy was calculated using the following formula:

[0111]

[0112] Results of field efficacy trials:

[0113] Table 10. Weed control efficacy of different treatments 14 days after application.

[0114]

[0115] Table 11 Control efficacy of different treatments on weeds 28 days after application.

[0116]

[0117] At 14 days post-application, the total herbicide composition of the present invention achieved a plant control efficacy of 86.21%–92.81% (see Table 10). At 28 days post-application, the total herbicide composition of the present invention achieved a plant control efficacy of 84.74%–91.77% and a total fresh weight control efficacy of 86.61%–96.20% (see Table 11), significantly higher than other treatment groups.

[0118] After rice transplanting, observations were conducted periodically. No phytotoxicity was observed in the rice under any of the treatments, and the seedlings grew normally with no significant difference from the control group, indicating that each treatment was safe for rice growth at the dosages used in this experiment.

[0119] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. Any changes or modifications made in accordance with the essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A herbicidal composition, characterized by comprising: The herbicidal composition comprises active ingredient A and active ingredient B, wherein active ingredient A is isoxaflutole or isoxaflutole methyl ester, and active ingredient B is pyrimethanil. The mass ratio of isoxaflutole to pyrimethanil is 1:5 to 9:1; and the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:6 to 6:

1.

2. The herbicidal composition according to claim 1, characterized by The mass ratio of isoxaflutole to pyrimethanil is 1:4 to 9:1; the mass ratio of isoxaflutole methyl ester to pyrimethanil is 1:4 to 6:

1.

3. The herbicidal composition according to claim 1, characterized by The herbicidal composition, calculated at 100 wt%, comprises active ingredient A and active ingredient B accounting for 1% to 80% of the total weight of the herbicidal composition.

4. The herbicidal composition according to claim 1, characterized by In addition to the active ingredient, the herbicidal composition also contains other auxiliary ingredients, which are selected from one or more of the following: wetting agents, dispersants, emulsifiers, thickeners, disintegrants, antifreeze agents, defoamers, solvents, preservatives, stabilizers, synergists, or carriers.

5. The herbicidal composition according to claim 1, characterized by The formulation prepared from the herbicidal composition is a liquid or solid formulation.

6. The herbicidal composition according to claim 5, characterized by The liquid formulation is a suspension, emulsifiable concentrate, dispersible oil suspension, microemulsion, or water emulsion; the solid formulation is a wettable powder, granule, or water-dispersible granule.

7. The application of the herbicidal composition according to any one of claims 1-6 for controlling weeds in paddy fields, characterized in that, The weeds mentioned are barnyard grass, angelica sinensis, and sedge.

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