Weeding composition for preventing and removing annual weeds in paddy field and preparation method of weeding composition

Abstract

The invention discloses a weeding composition and a preparation method thereof. The weeding composition comprises the following components in percentage by weight: 10-30% of propanil, 0.6-6% of fenquantel, 0.2-2% of cyclopropanesulfonamide, 2-6% of a stabilizer, 3-8% of a dispersing agent, 3-5% of an anti-freezing agent, 0.1-0.3% of a defoaming agent, 0.1-1% of a thickening agent and the balance of water. Wherein the ratio of propanil to fenquantel to the stabilizer is 5: (0.1-1): 1. The weeding composition provided by the invention can effectively prevent and remove annual weeds in paddy fields, is safe to paddy rice and high in preparation stability, has very high market value, and solves the problems of poor safety, environmental harm and the like in the process of preventing and removing annual weeds in paddy fields by using the existing medicament.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and in particular relates to a weed control composition for controlling annual weeds in rice fields and a preparation method thereof. Background Art

[0002] Propanil, also known as 3,4-dichlorophenylpropionamide, is a white, odorless, needle-shaped crystal with a melting point of 92-93°C and a solubility of 225 mg / L in water at 20°C. It is an amide-based contact herbicide for rice fields. Data from the China Pesticide Information Network website indicates that currently registered domestic formulations containing propanil include emulsifiable concentrates, dispersible oil suspensions, microemulsions, water-dispersible granules, and wettable powders. The preparation of propanil into emulsifiable concentrates or microemulsions typically requires the addition of large amounts of cyclohexanone, isophorone, and aromatic solvents. This poses a health risk to operators and users during production and use, wastes resources, and pollutes the environment. When prepared as wettable powders or water-dispersible granules, a large amount of dust is generated during processing. All of these formulations present environmental challenges. Patent CN108935470A discloses a propanil suspension concentrate and its preparation method. The background technology mentions that the propanil suspension concentrate is prone to crystallization during storage, and the solution is to use an ideal wetting dispersant to inhibit crystal growth through the dispersant's special steric hindrance effect. However, the invention does not provide particle size data after hot storage. Patent CN115918649A discloses a method for preparing an adjuvant for a propanil suspension concentrate and its application. However, the change in propanil particle size after the suspension concentrate is not mentioned. Since propanil has a certain solubility in water, its particle size easily grows during the preparation of the suspension concentrate, resulting in crystal precipitation in the product, reduced control efficacy, and thus loss of its commercial value.

[0003] Fenquinotrione (2-[8-chloro-3,4-dihydro-4-(4-methoxyphenyl)-3-oxyylidenebenzo[b]pyrazin-2-ylcarbonyl]cyclohexane-1,3-dione) is an arylcyclohexanedione herbicide developed by Kumihiko Chemical in Japan in 2008. It is a novel triketide containing an oxoquinoxaline structure and is an excellent herbicide for rice paddies. Currently, it is developed primarily in granules, wettable powders, and aqueous suspensions, and is used to control broadleaf weeds, grass weeds, and sedge weeds in rice paddies through soil sealing. However, frequent use of a single herbicide component can easily lead to weed resistance, posing a potential risk to weed control in rice fields and significantly shortening the product's lifecycle after market launch. Fenquinone is a novel herbicide class known as a 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor. It works by inhibiting the activity of 4-hydroxyphenylpyruvate dioxygenase (HPPD), an enzyme involved in the plastoquinone biosynthesis pathway in plants. When used in the rice seedling stage, it can easily cause plant bleaching, impacting rice safety.

[0004] Suspension concentrates (SCs) are environmentally friendly pesticide formulations. Their solvent is water, eliminating the need for hazardous solvents. The process produces no dust, making them highly recognized for their environmental friendliness compared to emulsifiable concentrates (ECs), microemulsions (MEs), wettable powders (WPs), and water-dispersible granules (WDGs). However, some compounds, such as propanil, experience particle growth in water, seriously impacting their effectiveness. Therefore, overcoming this particle growth issue with SCs is a pressing issue within the industry.

[0005] At present, due to the continuous use of a single herbicide in rice fields, weed resistance in rice fields is becoming more and more serious. In order to achieve better prevention and control effects, we can only continuously increase the dosage of pesticides, which will accelerate the development of weed resistance and bring more serious pollution to the environment.

[0006] Therefore, the development of stable, efficient and environmentally friendly pesticide compositions has become a key focus of the industry. Summary of the Invention

[0007] The content of this application is used to briefly introduce concepts that will be described in detail in the detailed description section below. The content of this application is not intended to identify key features or essential features of the technical solution for which protection is sought, nor is it intended to limit the scope of the technical solution for which protection is sought.

[0008] In order to overcome the deficiencies of the prior art, the present invention provides a herbicidal composition for controlling annual weeds in rice fields and a preparation method thereof.

[0009] To achieve the above object, the present invention adopts the following technical scheme: a herbicidal composition for controlling annual weeds in rice fields, wherein the herbicidal composition comprises, by weight percentage, 10-30% of propanil, 0.6-6% of fenquinoxaline, 0.2-2% of cyproconazole, 2-6% of a stabilizer, 3-8% of a dispersant, 3-5% of an antifreeze agent, 0.1-0.3% of a defoamer, 0.1-1% of a thickener, and the balance is water.

[0010] Furthermore, the mass ratio of propanil, fenquinoxaline and stabilizer is 5:(0.1-1):1.

[0011] Furthermore, the mass ratio of propanil, fenquinoxaline and stabilizer is 15:1:3.

[0012] Furthermore, the ratio of fenquinolone to ciprosulfamide is 2:1.

[0013] Furthermore, the stabilizer is one of nicotinamide, urea, glucose, α-lactose, and polyethylene glycol 400.

[0014] Furthermore, the dispersant is at least one of Agrilan 788, Atlox Metasperse 550S, MORWET D450, Atlox 4917, TERSPERSE 2500, and polyvinyl pyrrolidone K30.

[0015] Furthermore, the defoaming agent is one of SAG1572, SAG1522, and SAG630.

[0016] Furthermore, the thickener is at least one of magnesium aluminum silicate, AEROSIL 200, Min-u-GelFG, and xanthan gum.

[0017] Furthermore, the herbicidal composition for controlling annual weeds in rice fields is used for controlling annual weeds in rice fields.

[0018] Furthermore, the annual weeds are crabgrass and sedge.

[0019] As another aspect of the present application, a method for producing the above-mentioned herbicidal composition for controlling annual weeds in rice fields is also disclosed, comprising the following steps:

[0020] Step 1: Add propanil and stabilizer into a ball mill and grind to a first particle size to obtain material A;

[0021] Step 2: adding the material A into a shearing kettle, adding fenquinone, cyprosulfamide, dispersant, antifreeze, defoamer, thickener and water, and shearing uniformly to obtain material B;

[0022] Step 3: Grind the material B with a sand mill to a second particle size to obtain the herbicidal composition.

[0023] Furthermore, the median particle size of the first particle size is 10-20 microns, and the median particle size of the second particle size is 3-5 microns.

[0024] The present invention is beneficial in that:

[0025] 1. The herbicidal composition provided by the present invention has high physical stability, and the particle size does not show obvious growth after hot storage or freeze-thaw.

[0026] 2. The herbicidal composition provided by the present invention, in which propanil and fenquinoxaline are combined, has a significant synergistic effect, can reduce the dosage of pesticides used, can effectively control annual weeds in rice fields, and at the same time, the herbicidal composition is highly safe for rice.

[0027] 3. The herbicidal composition provided by the present invention does not contain organic solvents, does not generate dust during the production process, and is more environmentally friendly. DETAILED DESCRIPTION

[0028] The following specific embodiments of the present invention are described. Those skilled in the art can easily understand the other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are 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. In the following examples and comparative examples, unless otherwise stated, all percentages are weight percentages.

[0029] Example 1

[0030] Propanil 30%, Phenquat 2%, Cyprosulfamide 1%, Glucose 6%, Atlox Metasperse 550S 2%, Atlox 4917 2%, SAG630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, and the balance is water.

[0031] The preparation method of the above-mentioned herbicidal composition comprises:

[0032] Add propanil and glucose into a ball mill and grind to a first particle size to obtain material A;

[0033] The material A was added to a shearing kettle, and fenquinone, cyprosulfamide, Atlox Metasperse 550S, Atlox 4917, SAG630, Min-u-Gel FG, AEROSIL 200 and water were added, and sheared uniformly to obtain material B;

[0034] The material B is ground by a sand mill to a second particle size to obtain the herbicidal composition.

[0035] The median particle size of the first particle size is 10-20 microns, and the median particle size of the second particle size is 3-5 microns.

[0036] The preparation methods of the following examples are the same as those of Example 1.

[0037] Example 2

[0038] Propanil 30%, Phenylacetate 2%, Cyprosulfamide 1%, Glucose 6%, TERSPERSE 25002%, Agrilan788 2%, Defoamer SAG630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, and the balance is water.

[0039] Example 3

[0040] Propanil 30%, Fenquinone 6%, Cyprosulfamide 3%, Glucose 6%, Atlox Metasperse 550S 2%, Atlox 4917 2%, Defoamer SAG630 0.1%, Min-u-Gel FG

[0041] 0.5%, AEROSIL 200 0.5%, the balance is water.

[0042] Example 4

[0043] Propanil 30%, Phenquat 0.6%, Cyproconazole 0.3%, Glucose 6%, Atlox Metasperse 550S 2%, Atlox 4917 2%, Defoamer SAG 630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, the balance is water.

[0044] Comparative Example 1

[0045] Propanil 30%, Phenoxyethanol 2%, Glucose 6%, Atlox Metasperse 550S 2%, Atlox 4917 2%, Defoamer SAG 630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, and the balance is water.

[0046] The preparation method of this comparative example is the same as that of Example 1.

[0047] Comparative Example 2

[0048] Propanil 30%, Phenquat 2%, Cyprosulfamide 1%, Atlox Metasperse 550S 2%, Atlox 4917 2%, Defoamer SAG630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, the balance is water.

[0049] The preparation method of this comparative example is the same as that of Example 1.

[0050] Comparative Example 3

[0051] The components of this comparative example are the same as those of Example 1, but the processing method is different from that of Example 1. Instead, all the raw materials are mixed at one time, sand-milled, and debugged according to the conventional processing method in the industry.

[0052] Comparative Example 4

[0053] Propanil 30%, phenquat 2%, cyprosulfamide 1%, glucose 6%, 601 phosphate 2%, sodium lignin sulfonate 2%, defoamer SAG630 0.1%, Min-u-Gel FG 0.5%, AEROSIL 200 0.5%, balance water.

[0054] The preparation method of this comparative example is the same as that of Example 1.

[0055] Test Case

[0056] 1. Stability test

[0057] 200 g of each sample from Example 1-4 and Comparative Example 1-4 was weighed, added to a high-barrier bottle, sealed, and placed in a 54 ° C constant temperature box. After 14 days, the mass fraction and pH value of propanil, fenquinoxaline, and cyprosulfonamide were detected. The test results are shown in Table 1; and the hot storage decomposition rates of propanil, fenquinoxaline, and cyprosulfonamide were calculated. The results are shown in Table 2.

[0058] 200 g of each sample from Examples 1-4 and Comparative Examples 1-4 was weighed, placed in a high-barrier bottle, sealed, and placed in a high-low temperature alternating test chamber (-18°C for 16 hours, 45°C for 8 hours, one cycle per day). After 7 days, the particle size D90 of the samples after hot storage, freeze-thaw, and room temperature storage was measured using a laser particle size analyzer. The results are shown in Table 3.

[0059] Table 1 Mass fraction and pH value before and after heat storage

[0060]

[0061] Table 2 Thermal storage decomposition rate

[0062]

[0063]

[0064] The results showed that the pH values ​​of the samples of the herbicidal compositions of Examples 1-4 of the present invention did not change significantly before and after hot storage, and the decomposition rates of the three active ingredients, propanil, phenquinone, and cyproconazole, after hot storage were all less than 5%. The above content indicates that the herbicidal compositions provided by the present invention have excellent stability and meet the quality requirements of pesticide suspension concentrates.

[0065] Table 3 Particle size after hot storage and freeze-thaw

[0066] D90 before treatment, μm D90 after hot storage, μm After freeze-thaw, D90, μm Example 1 3.22 4.51 5.55 Example 2 3.30 4.29 5.64 Example 3 3.25 4.88 5.23 Example 4 3.56 4.37 5.16 Comparative Example 1 3.15 4.85 5.65 Comparative Example 2 3.24 38.64 58.43 Comparative Example 3 3.09 16.82 20.64 Comparative Example 4 3.22 7.52 8.39

[0067] The results showed that the herbicidal compositions of Examples 1-4 of the present invention showed only a minor increase in particle size after heat storage and freeze-thaw compared to before treatment, meeting industry quality requirements for aqueous suspension concentrates. The herbicidal composition of Comparative Example 2 did not contain the stabilizer glucose, while Comparative Example 3, although containing a stabilizer, was processed according to conventional industry methods for suspension concentrates. Both samples showed a significant increase in particle size after heat storage and freeze-thaw. This is because the amide group (-NH-CO-) of propanil may form a hydrogen bond network with the hydroxyl group (-OH) of glucose, reducing the intermolecular hydrogen bonds between the amide group (-NH-CO-) components in the propanil molecule. On the other hand, glucose is a hydrophilic molecule and will form hydrogen bonds with water molecules when dissolved, binding some water molecules and reducing the free water content. This effect may reduce the overall hydration degree of the system, thereby improving the stability of propanil in the herbicidal composition. At the same time, the herbicidal composition of the present invention selects polymer dispersants such as Atlox Metasperse 550S, Atlox4917, TERS PERSE 2500, and Agri lan788 to form a "flexible grid" around the crystals through a long chain structure, physically blocking the Ostwald ripening process of the crystals. Furthermore, the thickener of the present invention is AEROSIL 200 fumed silica is a nano-sized particle (7-40nm) with a very high specific surface area. These particles are evenly dispersed in the solution to form a three-dimensional network structure, which physically hinders the migration and aggregation of solute molecules (crystal precursors) and slows down the crystal nucleus growth rate. Through the synergistic effect of the above multiple mechanisms, the crystal growth phenomenon of propanil is finally avoided. However, a comprehensive analysis of Comparative Examples 1-4 shows that the key factor in controlling crystal growth is still because of the addition of stabilizers and special processing methods. Dispersants and thickeners have played an auxiliary role in suppressing the growth of crystals.

[0068] 2 Joint action test

[0069] Example 1 Determination of the combined effect of compound herbicides on crabgrass

[0070] Test weeds: Collect crabgrass seeds in the field and store them in the laboratory for future use. Test method: Put sieved fine soil into a plastic pot with holes, and use bottom irrigation to replenish water so that the soil is completely moist. Soak the crabgrass seeds for 24 hours, evenly sow them on the soil surface, sow 30 seeds per pot, and then cover them with 1 cm thick fine soil. Use bottom irrigation to replenish water until the soil is moistened, and place them in a greenhouse for heat preservation and cultivation. After a certain period of cultivation, remove the larger and weaker seedlings, and leave 20 weeds with the same leaf age and growth in each pot for treatment. Referring to the "Guidelines for Indoor Bioassay Tests of Pesticides", the stem and leaf treatment method is adopted, and the spray volume is 45 mL / m 2 , take the medicine once.

[0071] Survey Method: Surveys were conducted 21 days after treatment. Using the absolute value survey method, surviving weeds were cut along the soil surface with a razor blade and weighed using an analytical balance. Fresh weight weed control efficacy was calculated. Fresh weight weed control efficacy = (fresh weight of weeds in the control area - fresh weight of weeds in the treatment area) / fresh weight of weeds in the control area.

[0072] Combined effect: Gowing was used to evaluate the combined effect of the combination.

[0073] E0=X+Y(100-X) / 100; when E-E0>10%, it is a synergistic effect; when E-E0<-10%, it is an antagonistic effect; when the E-E0 value is between the theoretical value ±10%, it is an additive effect.

[0074] Table 4 Determination of the combined effect of the composite composition on crabgrass

[0075]

[0076]

[0077] Example 1 Determination of the combined effects of compound herbicides on glutinous rice

[0078] Test weeds: Lichang seeds were collected from the field and stored in the laboratory for future use.

[0079] Test method: Place sieved fine soil into a plastic pot with holes, and use bottom irrigation to replenish water to make the soil completely moist. Soak the seeds of Lichang for 24 hours, evenly sow them on the soil surface, sow 30 seeds per pot, and then cover them with 1 cm thick fine soil. Use bottom irrigation to replenish water until the soil is moist, place them in a greenhouse for heat preservation and cultivation. After a certain period of cultivation, remove the larger and weaker seedlings, and leave 20 weeds of the same leaf age and growth in each pot for treatment. Referring to the "Guidelines for Indoor Bioassay Tests of Pesticides", the stem and leaf treatment method was adopted, and the spray volume was 45 mL / m 2 , take the medicine once.

[0080] Survey Method: Surveys were conducted 21 days after treatment. Using the absolute value survey method, surviving weeds were cut along the soil surface with a razor blade and weighed using an analytical balance. Fresh weight weed control efficacy was calculated. Fresh weight weed control efficacy = (fresh weight of weeds in the control area - fresh weight of weeds in the treatment area) / fresh weight of weeds in the control area.

[0081] Combined effect: Gowing was used to evaluate the combined effect of the combination.

[0082] E0=X+Y(100-X) / 100; when E-E0>10%, it is a synergistic effect; when E-E0<-10%, it is an antagonistic effect; when the E-E0 value is between the theoretical value ±10%, it is an additive effect.

[0083] Table 5 Determination of the combined effect of the compound composition on the sweet intestine

[0084]

[0085] Tables 4 and 5 show the indoor activity of propanil and fenquinoxaline alone and in combination against crabgrass and sedge, as well as the types of combined effects of the combined compounds. It was found that propanil and fenquinoxaline produced synergistic or additive effects on both crabgrass and sedge within the experimental ratio range. When the propanil to fenquinoxaline ratio was 15:1, the combined composition had a significant synergistic effect on both sedge and sedge, while other ratios showed additive or synergistic effects. When the combination showed a synergistic effect, the dosage of the active ingredient could be significantly reduced, improving the control effect. This shows the rationality and feasibility of the propanil and fenquinoxaline combination.

[0086] 3. Testing of different safeners

[0087] The compositions, adjuvant ratios and preparation methods of Example 1 were followed, with only the safener and safener dosage in the formula being replaced.

[0088] Test weeds: seeds of Digitaria sanguinalis and Digitaria truncatula were collected from the field and stored in the laboratory for future use.

[0089] Test rice: Y Liangyou 1998

[0090] Test method: put the sieved fine soil into a plastic pot with holes, and use the bottom of the pot to replenish water to make the soil completely moist. Soak the seeds of crabgrass, sweet intestine and rice for 24 hours, evenly sow them on the soil surface, sow 30 seeds per pot, and then cover with 1cm thick fine soil. Use the bottom of the pot to replenish water until the soil is moist, place it in a greenhouse for heat preservation and cultivation, and after a certain period of cultivation, remove the larger and weaker seedlings, and leave 20 weeds with the same leaf age and growth in each pot for treatment. According to the "Guidelines for Indoor Bioassay Tests of Pesticides", the stem and leaf treatment method is adopted, and the spray volume is 45mL / m 2 , take the medicine once.

[0091] Survey Method: Survey once 21 days after treatment. Using the absolute value survey method, surviving weeds were cut along the soil surface with a razor blade and weighed on an analytical balance to calculate the fresh weight control efficacy. Fresh weight weed control efficacy = (fresh weight of weeds in the control area - fresh weight of weeds in the treatment area) / fresh weight of weeds in the control area.

[0092] Rice plant height inhibition rate = (blank group plant height - control group plant height) / blank group plant height.

[0093] Table 6 Safety of different safeners on rice

[0094]

[0095] When safeners such as cloquintocet-mexyl, fenpyroximate, and fenpyroximate were added to the herbicidal composition, the height of rice plants was significantly suppressed, and the rice showed obvious albinism. Although the rice grew normally when isoxadifen-ac was added, the herbicidal effect was significantly inhibited. When fenpyroximate: cyclopropylsulfonamide was added in a mass ratio of 2:1, the herbicidal effect was ideal, and the rice grew normally.

[0096] 4. Tests of different dosages of stabilizer

[0097] According to the composition and auxiliary agent ratio and preparation method of Example 1, only the amount of stabilizer glucose was adjusted to test the particle size growth of the product.

[0098] Table 7 Particle size data of different glucose dosages

[0099] Propanil: Glucose Original particle size Particle size after 14 days of hot storage Particle size after 14 days of freeze-thaw 1:1 3.2 4.2 5.6 3:1 3.3 4.4 5.5 5:1 3.2 4.5 5.3 7:1 3.1 5.4 7.2 10:1 3.4 12.6 16.5 CK 3.2 45.2 56.7

[0100] As shown in the table above, the addition of different amounts of glucose inhibited particle size growth of the herbicidal composition after hot storage and freeze-thaw treatment to a certain extent. When the propanil:glucose ratios were 1:1, 3:1, and 5:1, particle size was effectively controlled during hot storage and freeze-thaw treatment. In CK, where glucose was not added, particle size growth was significant after hot storage and freeze-thaw treatment. However, when the propanil:glucose ratio was 1:1 or 3:1, the herbicidal composition had a high viscosity, making it unsuitable for use as a suspension concentrate.

[0101] 5. Field efficacy and safety testing

[0102] Test agents: the herbicidal compositions of Examples 1-4, Comparative Examples 1-4, 34% propanil suspension concentrate, and 10% fenquinoxaline suspension concentrate.

[0103] Experiment Date: July 2, 2024

[0104] Test location: Fuyang, Anhui

[0105] Planting method: Direct-seeding rice, rice 3-leaf stage

[0106] Field weeds include Leptochloa chinensis, Digitaria sanguinalis, Echinochloa crusgalli, Cyperus rotundus, Duck tongue grass, Lichangsi, and Water bamboo leaves.

[0107] Experimental method: Select fields with uniform weed distribution and uniform rice growth. No herbicides were used for stem and leaf treatment during the test season. Each treatment was 100m 2 , set up three replicates. The pesticide application method is to use a backpack electric sprayer to spray evenly without double spraying or missing sprays.

[0108] Survey method: Randomly select 4 points in each plot, and survey 0.25m at each point 2 The fresh weight of aboveground weeds was investigated 21 days after application. Since weeds in the blank control area were mostly grasses and broadleaf weeds of varying species, the experimental investigation focused on grasses and broadleaf weeds, specifically the grass weed Digitaria sanguinea and the broadleaf weed Lichang. The aboveground fresh weight control efficacy was calculated for each of these groups. The results are shown in Table 8.

[0109] Table 8 Field control efficacy and safety

[0110]

[0111]

[0112] Test agents: the herbicidal compositions of Examples 1-4, Comparative Examples 1-4, 34% propanil emulsifiable concentrate, 34% propanil suspension concentrate, and 10% fenquinoxaline suspension concentrate.

[0113] Experiment Date: July 4, 2024

[0114] Test location: Qianjiang, Hubei

[0115] Planting method: Direct-seeding rice, rice 3-leaf stage

[0116] Field weeds include Leptochloa chinensis, Digitaria sanguinalis, Echinochloa crusgalli, Cyperus rotundus, Duck tongue grass, Lichangsi, and Water bamboo leaves.

[0117] Experimental method: Select fields with uniform weed distribution and uniform rice growth. No herbicides were used for stem and leaf treatment during the test season. Each treatment was 100m 2 , set up three replicates. The pesticide application method is to use a backpack electric sprayer to spray evenly without double spraying or missing sprays.

[0118] Survey method: Randomly select 4 points in each plot, and survey 0.25m at each point 2The fresh weight of aboveground weeds was investigated 21 days after application. Since weeds in the blank control area were mostly grasses and broadleaf weeds of various species, the experimental investigation first focused on grasses and broadleaf weeds, specifically the grass weed Digitaria sanguinea and the broadleaf weed Lichang tang. The aboveground fresh weight control efficacy was calculated for each of these groups.

[0119] Table 9 Field control efficacy and safety

[0120]

[0121]

[0122] The herbicidal compositions of Examples 1-4 had good control effects on annual weeds in rice fields, including Leptochloa chinensis, Digitaria sanguinalis, Echinochloa crus-galli, Cyperus rotundus, Dalbergia vaginalis, Ligusticum chuanxiong, and Water bamboo leaves, 21 days after application, and the agents were safe to rice. In Comparative Example 1, no safener was added. Although the control effect was good, it had a certain impact on the safety of rice. When a commercially available 34% propanil emulsifiable concentrate was combined with a homemade 10% fenquinoxaline suspension concentrate without a safener, the phytotoxicity was more obvious. This is because the propanil emulsifiable concentrate contains a large amount of organic solvent, which increases the damage of the agent to the wax layer of rice, thereby aggravating the phytotoxicity.

[0123] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A herbicidal composition for controlling annual weeds in rice fields, characterized in that: The herbicidal composition comprises, by weight percentage, 10-30% of propanil, 0.6-6% of fenquinone, 0.2-2% of cyproconazole, 2-6% of stabilizer, 3-8% of dispersant, 3-5% of antifreeze agent, 0.1-0.3% of defoamer, 0.1-1% of thickener, and the balance is water.

2. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The mass ratio of the propanil, fenquinoxaline and stabilizer is 5:(0.1-1):

1.

3. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The mass ratio of the propanil, fenquinoxaline and stabilizer is 15:1:

3.

4. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The ratio of fenquinolone to cyprosulfamide is 2:

1.

5. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The stabilizer is one of nicotinamide, urea, glucose, α-lactose, and polyethylene glycol 400.

6. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The dispersant is at least one of Agrilan788, Atlox Metasperse 550S, MORWET D450, Atlox 4917, TERSPERSE2500, and polyvinylpyrrolidone K30.

7. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The defoaming agent is one of SAG1572, SAG1522, and SAG630.

8. The herbicidal composition for controlling annual weeds in rice fields according to claim 1, characterized in that: The thickener is at least one of magnesium aluminum silicate, AEROSIL 200, Min-u-Gel FG, and xanthan gum.

9. A method for producing the herbicidal composition for controlling annual weeds in rice fields according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Add propanil and stabilizer into a ball mill and grind to a first particle size to obtain material A; Step 2: adding the material A into a shearing kettle, adding fenquinone, cyprosulfamide, dispersant, antifreeze, defoamer, thickener and water, and shearing uniformly to obtain material B; Step 3: Grind the material B with a sand mill to a second particle size to obtain the herbicidal composition.

10. The method for preparing the herbicidal composition for controlling annual weeds in rice fields according to claim 9, characterized in that: The median particle size of the first particle size is 10-20 microns, and the median particle size of the second particle size is 3-5 microns.

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