Herbicidal composition, herbicide and use thereof

Abstract

The application discloses a kind of herbicide composition, the active ingredient of the composition includes mesosulfuron-methyl and quinclorac, the mass ratio of mesosulfuron-methyl and quinclorac is (0.15-9.57):1.Mesosulfuron-methyl and quinclorac of the present application both show the effect of addition or synergism, are very safe in warm-season turf St. Augustine grass lawn, and the common action of both makes the herbicide have good effect on the removal of gramineae weeds in warm-season turf, and environmental pollution is less, can be widely applied.

Description

Technical Field

[0001] This invention relates to the field of agricultural herbicide technology, specifically to a herbicidal composition, herbicide, and its application. Background Technology

[0002] Turfgrasses can be classified into warm-season and cool-season grasses based on their ecological adaptability to temperature. Warm-season grasses thrive best in temperatures between 25 and 35 degrees Celsius and can survive safely in temperatures ranging from -5 to 42 degrees Celsius. These grasses grow vigorously in summer or warmer regions. Zoysia japonica is a relatively cold-resistant species among warm-season turfgrasses. While warm-season turfgrasses are in high demand and come in many varieties, they are susceptible to the influence of strong-rooted, high-reproductive grasses (such as Imperata cylindrica), which can reduce their reproductive capacity and hinder their normal growth.

[0003] In lawn maintenance, weed control is a very demanding task. Manual weeding is costly, incomplete, and prone to recurrence. A more effective method is to use selective chemical herbicides to control lawn weeds. According to the China Pesticide Information Network, as of December 2021, there were 24 herbicides registered in China for lawn weed control, mainly involving the following ingredients: pyrimisulfuron, mesotrione, ambroxol, clopyralid, diflubenzuron, ambroxol, dicamba, quizalofop-p-ethyl, 2,4-D sodium, triflusulfuron, etc.

[0004] However, the above-mentioned herbicides are not very effective against grassy weeds. Long-term use will lead to increasingly severe weed infestations, greatly affecting lawn growth. Excessive grassy weeds can cause lawn degradation, and in severe cases, lawn death, affecting the landscape. Controlling grassy weeds in lawns is a technical challenge that plagues landscape maintenance workers. Herbicides safe for turfgrass have no significant effect on grassy weeds, while herbicides effective against grassy weeds are unsafe for turfgrass. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a weeding composition, herbicide, and its application. It exhibits good control of grassy weeds such as cogongrass, provides high lawn safety, and minimizes environmental pollution.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a herbicidal composition comprising mefensulfuron-methyl and quinclorac acid as active ingredients, wherein the mass ratio of mefensulfuron-methyl to quinclorac acid is (0.15–9.57):1.

[0008] Preferably, the mass ratio of methasulfuron to quinclorac is (1.2–2.4):1.

[0009] In a second aspect, the present invention provides a herbicide comprising the herbicidal composition and an adjuvant.

[0010] Preferably, the auxiliary agent is sodium p-chlorophenoxyacetate.

[0011] Preferably, the ratio of the total mass of the methasulfuron-methyl and dichloroquinoline acid to the mass of the sodium p-chlorophenoxyacetate is (240-510):1.

[0012] More preferably, the ratio of the total mass of methasulfuron and dichloroquinoline acid to the mass of sodium p-chlorophenoxyacetate is (330-510):1.

[0013] Thirdly, the present invention provides an application of the aforementioned weed-control composition or herbicide in controlling grassy weeds in warm-season lawns.

[0014] Preferably, the warm-season turf of the present invention is zoysia japonica.

[0015] Preferably, the grassy weeds mentioned in this invention are cogongrass, crabgrass, foxtail grass, barnyard grass, etc.

[0016] Preferably, the application rate of the active ingredient in the composition or the herbicide is 0.0225–0.09 g / m³ of mefensulfuron-methyl. 2 0.0375–0.075 g / m³ of quincloracine 2 Sodium p-chlorophenoxyacetate 0.00025 g / m 2 .

[0017] Preferably, the application conditions of the herbicidal composition or herbicide of the present invention are: watering the day before or on a sunny day after rain, with clear skies and no wind, during the time period of 9:00-11:00 or 15:00-18:00.

[0018] Preferably, the application method of the herbicide composition or herbicide of the present invention includes any one of the following: whole-field foliar spraying, directional spraying, directional application, aerial application, and mechanical spraying.

[0019] The beneficial effects of this invention are:

[0020] The active ingredients of the herbicidal composition of this invention are methimazole and quinclorac acid. The combination of the two exhibits additive and synergistic effects, and is very safe for Zoysia japonica in warm-season lawns. As a systemic grass herbicide, quinclorac acid can enhance the absorption of methimazole by grass weeds. The combined effect of the two makes the herbicide effective in removing grass weeds in warm-season lawns, with less environmental pollution, and can be widely promoted and applied.

[0021] The present invention adds sodium p-chlorophenoxyacetate to the composition to regulate hormones in the plant, promote the plant's absorption of water and pesticide solution, and enable methimazole and quinclorac acid to be better absorbed by weeds of this family. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solution of the invention, the invention will be further described in detail below with reference to specific embodiments.

[0023] This invention develops a herbicide formulation suitable for warm-season lawns, which is effective in controlling grassy weeds such as cogongrass, has high lawn safety, causes less environmental pollution, and can be widely applied.

[0024] Specifically, in a first aspect, the present invention provides a herbicidal composition, the active ingredients of which include methasulfuron-methyl and quinclorac acid, wherein the mass ratio of methasulfuron-methyl to quinclorac acid is (0.15–9.57):1. Exemplarily, the mass ratio of methasulfuron-methyl to quinclorac acid is any one of 0.15:1, 0.3:1, 0.6:1, 1.2:1, 2.4:1, 4.8:1, 9.57:1, or a value between both. Preferably, the mass ratio of methasulfuron-methyl to quinclorac acid is 1.2:1 or 2.4:1.

[0025] Methimazole, a sulfonylurea non-selective herbicide, is systemic, inhibits the synthesis of branched-chain amino acids, suppresses cell division in plant meristems, and prevents plant growth. Plants exhibit significant reddish-purple discoloration, chlorosis, necrosis, vein chlorosis, and terminal bud death. It is typically used on non-cultivated land, effectively killing almost any weed, leaving the land barren. However, the inventors of this application have creatively discovered through extensive research that the combined use of methimazole and quinclorac is very safe for Zoysia japonica in warm-season lawns. Quinclorac, as a systemic grass herbicide, enhances the absorption of methimazole by grass weeds. The synergistic effect of the two herbicides results in a highly effective removal of grass weeds in warm-season lawns.

[0026] In a second aspect, the present invention provides a herbicide comprising the herbicidal composition and an adjuvant.

[0027] Preferably, the adjuvant is sodium p-chlorophenoxyacetate. This regulates hormones within the plant, promotes water and herbicide absorption, and allows for better absorption of methasulfuron-methyl and quinclorac by weeds of this family. In some embodiments of the invention, the mass ratio of the total mass of methasulfuron-methyl and quinclorac to the mass of sodium p-chlorophenoxyacetate is (240–510):1. Preferably, the mass ratio of the total mass of methasulfuron-methyl and quinclorac to the mass of sodium p-chlorophenoxyacetate is (330–510):1.

[0028] The herbicide of the present invention also includes pesticide-acceptable excipients.

[0029] The herbicides described in this invention can be in conventional forms in the art, such as solid formulations (e.g., granules) or liquid formulations (e.g., wettable powders, emulsions, or emulsifiable concentrates).

[0030] In some embodiments of the present invention, the methasulfuron is a commercially available dispersible granule, the dichloroquinoline acid is a commercially available saline solution, and the sodium p-chlorophenoxyacetate is a commercially available soluble solution. All of these commercially available sources are conventionally chosen in the art. It should be noted that regardless of the dosage form of the composition, as long as the active ingredients meet the mass ratio described in the present invention, the technical effects described in the present invention can be achieved.

[0031] Thirdly, the present invention provides an application of the herbicide in controlling grassy weeds in warm-season lawns.

[0032] Preferably, the warm-season turf of the present invention is zoysia japonica.

[0033] Preferably, the grassy weeds mentioned in this invention are cogongrass, crabgrass, foxtail grass, barnyard grass, etc.

[0034] In the application of this invention, the effective ingredient of the composition or herbicide is applied at a rate of 0.0225–0.09 g / m³. 2 0.0375–0.075 g / m³ of quincloracine 2 Sodium p-chlorophenoxyacetate 0.00025 g / m 2 .

[0035] The application conditions for the herbicidal composition or herbicide of this invention are as follows: Apply between 9:00-11:00 or 15:00-18:00 on a sunny, windless day after watering or following rain. During this time period, the temperature is suitable, and the lenticels are open while the plant is absorbing water, which is beneficial for the absorption of the herbicide.

[0036] The herbicide of this invention can also be combined with broadleaf herbicides such as triclopyralid butoxyethyl ester, dimethyl tetrachloroisooctyl ester, dichloropyridine acid, etc. to control all weeds other than the grass in Zoysia japonica lawn.

[0037] The application methods of the herbicidal composition or herbicide of the present invention include any one of the following: whole-field foliar spraying, directional spraying, directional application, aerial application, and mechanical spraying.

[0038] It should be noted that when applying the herbicidal composition or herbicide of the present invention, each effective ingredient of the present invention may be applied separately or simultaneously.

[0039] The above is a detailed description of the present invention. The following are embodiments of the present invention.

[0040] Example 1

[0041] The preparation method of the herbicide in this embodiment is as follows:

[0042] S1. Add 0.3g of 75% mefenamic acid water-dispersible granules to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0043] S2. Add 2.34g of 32% quinclorac acid aqueous solution to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0044] S3. Add 0.25g of 1% sodium p-chlorophenoxyacetate soluble agent to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0045] S4. Pour the reagents obtained in S1, S2 and S3 into a 1L beaker, mix well and add water to 700ml. Then take out 70ml to obtain 630ml of mixed solution.

[0046] In this embodiment, the mass ratio of methasulfuron-methyl: quinclorac acid: sodium p-chlorophenoxyacetate in the herbicide composition is 90:300:1.

[0047] Example 2

[0048] The preparation method of the herbicide in this embodiment is as follows:

[0049] S1. Add 0.3g of 75% mefenamic acid water-dispersible granules to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0050] S2. Add 1.17g of 32% quinclorac acid aqueous solution to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0051] S3. Add 0.25g of 1% sodium p-chlorophenoxyacetate soluble agent to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0052] S4. Pour the reagents obtained in S1, S2 and S3 into a 1L beaker, mix well and add water to 700ml. Then take out 70ml to obtain 630ml of mixed solution.

[0053] In this embodiment, the mass ratio of methasulfuron-methyl: quinclorac acid: sodium p-chlorophenoxyacetate in the herbicide composition is 90:150:1.

[0054] Example 3

[0055] The preparation method of the herbicide in this embodiment is as follows:

[0056] S1. Add 0.6g of 75% mefenamic acid water-dispersible granules to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0057] S2. Add 1.17g of 32% quinclorac acid aqueous solution to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0058] S3. Add 0.25g of 1% sodium p-chlorophenoxyacetate soluble agent to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0059] S4. Pour the reagents obtained in S1, S2 and S3 into a 1L beaker, mix well and add water to 700ml. Then take out 70ml to obtain 630ml of mixed solution.

[0060] In this embodiment, the mass ratio of methasulfuron-methyl: quinclorac acid: sodium p-chlorophenoxyacetate in the herbicide composition is 180:150:1.

[0061] Example 4

[0062] The preparation method of the herbicide in this embodiment is as follows:

[0063] S1. Add 1.2g of 75% mefenamic acid water-dispersible granules to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0064] S2. Add 1.17g of 32% quinclorac acid aqueous solution to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0065] S3. Add 0.25g of 1% sodium p-chlorophenoxyacetate soluble agent to a beaker containing 100ml of water, and stir thoroughly to ensure that the agent is completely dispersed in the water;

[0066] S4. Pour the reagents obtained in S1, S2 and S3 into a 1L beaker, mix well and add water to 700ml. Then take out 70ml to obtain 630ml of mixed solution.

[0067] In this embodiment, the mass ratio of methasulfuron-methyl: quinclorac acid: sodium p-chlorophenoxyacetate in the herbicide composition is 360: 150: 1.

[0068] Example of effect 1

[0069] The herbicide used in this study was sprayed on a warm-season furrowed zoysia lawn to investigate the safety of the turfgrass and the mortality of cogongrass among grass weeds. The study also explored the synergistic effect of the composition in controlling grass weeds and determined the optimal ratio of the composition.

[0070] 1. Lawn pretreatment: The lawn species was a warm-season furrowed zoysia. The lawn management level was consistent, and the fertility was uniform and moderate. The main weeds in the test area were broadleaf weeds, cogongrass, which were evenly distributed. The lawn was mowed to the same height with a push-type weed cutter and the blade was set to about 3cm.

[0071] 2. Preparation of the medicine: The herbicides obtained in Examples 1-4 and the control group were sprayed with water, with 630 mL of water used in the control area. Each treatment was repeated 3 times.

[0072] 3. Test methods: On September 24, 2021, 15 sample plots were selected in areas where Zoysia japonica and Imperata cylindrica were severely damaged. Each plot had an area of ​​3m × 3m = 9m². 2 Water the lawn the day before application or on a sunny, windless day after rain. Use a backpack sprayer to evenly spray the grass weeds "Cogongrass" between 9:00-11:00 or 15:00-18:00. Do not overspray or miss any areas. The application rate is shown in the table below.

[0073] Table 1. Dosage of effective ingredients in each embodiment

[0074]

[0075] 4. Evaluation Method:

[0076] 4.1 Evaluation of the combined effects of the compositions

[0077] The synergistic effect of herbicide combinations was evaluated using the Gowing method, a method proposed in 1960 for evaluating the synergistic effects of herbicide mixtures. The specific steps are as follows: First, the efficacy of the single herbicide and the mixture against the target weeds is determined. The theoretical efficacy of the mixture is calculated from the measured efficacy of the single herbicide, and then compared with the measured efficacy of the mixture to evaluate the synergistic effect type.

[0078] The formula for calculating the mixing effect using the Gowing method is:

[0079] E0 = X + Y – XY / 100

[0080] X represents the weed control efficacy of herbicide A at a dosage of P; Y represents the weed control efficacy of herbicide B at a dosage of Q; E0 represents the theoretical control efficacy of herbicide (A+B) at a dosage of (P+Q), where E represents the measured control efficacy % for each treatment. According to the Gowing method, when E-E0>10%, it indicates a synergistic effect of the mixed herbicides; when E-E0<-10%, it indicates an antagonistic effect; and when E-E0 is between ±10%, it indicates an additive effect.

[0081] 4.2 Lawn Safety Evaluation

[0082] (1) Level of phytotoxicity

[0083] The lawn growth was investigated 3, 7 and 15 days after application of the herbicide. The lawn safety was assessed according to Wei Fuxiang's herbicide damage test method. The growth status, color and leaf condition of the lawn ground cover plants were observed after application. The degree of herbicide damage to the lawn grass was scored. The scoring method is shown in Table 2.

[0084] Table 2 Lawn Herbicide Damage Levels

[0085]

[0086] (2) Lawn pesticide damage index:

[0087] After application of the pesticide, observe the pesticide damage to the lawn, and count the pesticide damage level and number of plants in each treatment. Calculate the pesticide damage index according to formula (1). Conduct surveys at 3, 7, and 15 days after application, for a total of 3 surveys, and calculate the average value, which is recorded as the average pesticide damage index of the lawn.

[0088]

[0089] In the formula: I P The pesticide damage index; G i Level of pesticide damage; L i The number of plants at this level of pesticide damage; L s To investigate the total number of plants; G m This is the highest level of pesticide damage.

[0090] (3) Plant height inhibition rate and growth rate inhibition rate:

[0091] Ten sampling points were randomly selected from each plot to measure the natural height of the lawn and calculate the plant height inhibition rate and growth rate inhibition rate.

[0092]

[0093]

[0094]

[0095] In the formula: Ht H0 represents the height of the control lawn after t days (cm); H0 represents the height of the control lawn (cm); ΔH t The lawn growth rate (cm / d) in the control area; h t t represents the lawn height in the treated area after t days (cm); h0 represents the lawn height in the treated area (cm); Δh t E represents the lawn growth rate (cm / d) in the treatment area. h Plant height inhibition rate (%).

[0096] 4.3 Weed control efficacy of corrected plant strains

[0097] Record the number of Imperata cylindrica plants in the sample area before and after spraying the pesticide at 3, 7 and 15 days after application, and calculate the corrected control efficacy of Imperata cylindrica.

[0098]

[0099] E represents the control efficacy (%) of the corrected plant; CK0 represents the number of weeds in the blank control area before application; CKt represents the number of weeds in the blank control area after application; P0 represents the number of weeds in the herbicide-treated area before application; Pt represents the number of weeds in the herbicide-treated area after application.

[0100] 5. Test Results:

[0101] 5.1 Evaluation of the combined effects of the compositions

[0102] Table 3 Evaluation results of the herbicidal activity and combined effects of different ratios of the composition on Imperata cylindrica

[0103]

[0104] The results showed that the combined effect evaluation of the herbicides indicated that the measured control efficacy (E) of most herbicide compositions against the tested weeds was greater than the theoretical control efficacy (E0). When the ratio of mefenoxam to quinclorac was 1.2 and 2.4, the E-E0 value was greater than 10%, indicating a synergistic effect. When the proportion of quinclorac or mefenoxam was low, the combined effect was additive, and no antagonistic effect was observed.

[0105] 5.2 Lawn Safety Evaluation

[0106] (1) Level of phytotoxicity

[0107] After 3, 7, and 15 days of application of the herbicides in Examples 1-4, no herbicide damage such as yellowing, bending, or wilting of leaves was observed in the Zoysia japonica lawn. The herbicide damage level of the lawn was 0, indicating that the herbicide of the present invention is safe for Zoysia japonica lawn.

[0108] (2) Lawn pesticide damage index

[0109] After applying the herbicides of Examples 1-4 for 3 days, 7 days, and 15 days, the herbicide damage index was calculated according to formula (1), and the lawn herbicide damage level was 0, indicating that the herbicide of the present invention is safe for Zoysia japonica lawn.

[0110] (3) Plant height inhibition rate and growth rate inhibition rate

[0111] Plant height and growth rate were tested on lawns treated with herbicides from Examples 1 to 4 after 3, 7, and 15 days. The results are shown in Tables 4 and 5.

[0112] Table 4. Effects of herbicides on the plant height inhibition of Zoysia japonica lawn.

[0113]

[0114] Note: All data above are averages, n=3.

[0115] Table 4 shows that 3 days after application, the turfgrass treated with herbicides in Examples 1-4 was significantly shorter than the control. There was no significant difference in the inhibition rate of turfgrass height among the treatments, ranging from 69.44% to 80.55%. 7 days after application, the turfgrass treated with herbicides in Examples 1-4 was still significantly shorter than the control. There was no significant difference in the inhibition rate of turfgrass height among the treatments, but the inhibition rate was lower than that 3 days after application, ranging from 24.53% to 28.39%. 15 days after application, the inhibition rate of turfgrass height decreased among the treatments, ranging from 5.87% to 7.05%.

[0116] Table 5. Effects of herbicides on the growth rate inhibition of Zoysia japonica lawns.

[0117]

[0118] Note: All data above are averages, n=3.

[0119] Table 5 shows that, 3 days after application, the growth rate of *Zoysia japonica* turfgrass treated with the herbicides in Examples 1-4 was significantly lower than that of the control turfgrass. 7 days after application, the growth rate of *Zoysia japonica* turfgrass treated with the herbicides in Examples 1-4 was still significantly lower than that of the control turfgrass, with no significant effect on the overall growth rate of *Zoysia japonica* turfgrass in any treatment. Compared to the turfgrass 3 days after application, the growth rate of *Zoysia japonica* turfgrass treated with the herbicides in Examples 1-4 increased by 13-18 times after 7 days, while the growth rate in the control area increased by 3-4 times. 15 days after application, there was no significant difference in the growth rate of *Zoysia japonica* turfgrass treated with the herbicides in Examples 1-4 and the control group, with a growth rate of 0.2 cm / d.

[0120] The above results indicate that the herbicide of this invention did not cause significant phytotoxicity to Zoysia japonica lawns. Three days after application, the lawn growth rate was lower than the control treatment; seven days after application, the lawn growth rate was still lower than the control treatment; however, by 15 days after application, there was no significant difference in the growth rate between the treated and control lawns, and the growth rate of the control lawn gradually slowed down over time. Considering the combined results of phytotoxicity level, plant height inhibition rate, and growth rate, it can be concluded that the herbicide of this invention is safe for Zoysia japonica lawns.

[0121] 5.3 Evaluation of herbicidal activity

[0122] The herbicides tested in Examples 1-4 and the control group showed effective control of Imperata cylindrica in Zoysia japonica lawns. The results are shown in Table 6.

[0123] Table 6. Control efficacy of herbicides against Cogongrass in Zoysia japonica lawns.

[0124]

[0125] Note: All data above are averages, n=3.

[0126] Table 6 shows that 3 days after spraying, the upper tips of the leaves of *Imperata cylindrica* in the treated *Zoysia japonica* lawn were slightly yellowed, and a small number of younger *Imperata cylindrica* plants died. The control efficacy per plant in Example 1 was approximately 14.19%, in Example 2 it was 6.40%, and in Examples 3 and 4 it reached 20%. The control efficacy of Examples 3 and 4 against *Imperata cylindrica* was significantly higher than that in Examples 1 and 2. 7 days after spraying, the upper tips of the leaves of *Imperata cylindrica* in the treated *Zoysia japonica* lawn were completely withered and yellowed, and the internodes turned black and brown. The control efficacy per plant in Example 1 was approximately 48.54%, in Example 2 it was only 38.62%, and in Examples 3 and 4 it reached over 60%. The control efficacy of Examples 3 and 4 against *Imperata cylindrica* was significantly higher than that in Examples 1 and 2. Fifteen days after spraying the pesticide, the above-ground parts of the grass in the treated Zoysia japonica lawn were completely withered and yellowed, the internodes turned black and brown, and the roots turned black and necrotic. The control efficacy of Examples 3 and 4 on grass was over 95%. The control efficacy of Examples 3 and 4 on grass was significantly higher than that of Examples 1 and 2. There was no significant difference between Examples 1 and 2.

[0127] Considering both lawn safety and cogongrass control efficacy, the herbicides in Examples 1-4 are all safe for Zoysia japonica lawns, and all Examples 1-4 are effective against cogongrass. Among them, Examples 1 and 2 have a plant control efficacy of about 78%, while Examples 3 and 4 have a plant control efficacy of over 95% against cogongrass. Considering the control efficacy and the cost of the herbicide, the herbicide in Example 3 is preferred.

[0128] Example 2: Control of cogongrass and white grass on cool-season Kentucky bluegrass lawns.

[0129] The herbicides of the present invention were sprayed on cool-season Kentucky bluegrass lawns to explore the applicability of the herbicidal composition of the present invention to cool-season lawns.

[0130] 1. Lawn pretreatment: The lawn species was cool-season Kentucky bluegrass, with consistent lawn management and uniform to moderate fertility. The main weeds in the test area were broadleaf weeds, cogongrass, which were evenly distributed. The lawn was mowed to the same height using a push-type weed cutter with the blade set to about 3cm.

[0131] 2. Preparation of the medicine: Same as in Example 1.

[0132] 3. Experimental method: The lawn species was Kentucky bluegrass cool-season type, and the other settings were the same as in Example 1.

[0133] 4. Evaluation method: Same as Example 1.

[0134] 5. Test Results:

[0135] 5.1 Lawn Safety Assessment

[0136] The herbicides obtained in Examples 1-4 were applied to Kentucky bluegrass lawns, and the herbicide damage to the lawns was observed 3, 7, and 15 days after application. The average herbicide damage index of the lawns was calculated, as shown in Table 7.

[0137] Table 7 Herbicide Damage Index to Kentucky Blue Turfgrass

[0138]

[0139] Note: All data above are averages, n=3.

[0140] Table 5 shows that the herbicide caused phytotoxicity to Kentucky bluegrass lawns after 3, 7, and 15 days of application. After 3 days, the phytotoxicity level was 1, with phytotoxicity indices of 68.00, 69.33, 70.00, and 72.66 for Examples 1, 2, 3, and 4, respectively. After 7 days, the phytotoxicity levels were 2 and 3, with phytotoxicity indices of 67.55, 79.33, 68.67, and 70.22 for Examples 1, 2, 3, and 4, respectively. After 15 days, the phytotoxicity levels were 3 and 4, with phytotoxicity indices of 76.16, 81.00, 80.33, and 83.17 for Examples 1, 2, 3, and 4, respectively. All herbicides were unsafe for Kentucky bluegrass lawns; after 15 days, the lawn growth almost stopped, and all leaves withered. This indicates that the herbicide of this invention is only suitable for weed control in warm-season lawns and not for weed control in cool-season lawns.

[0141] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a herbicide to control grassy weeds in warm-season lawns, characterized in that, The herbicide comprises a herbicidal composition and an adjuvant. The active ingredients of the herbicidal composition include mefensulfuron-methyl and quinclorac acid. The adjuvant is sodium p-chlorophenoxyacetate. The mass ratio of mefensulfuron-methyl to quinclorac acid is (1.2~2.4):

1. The mass ratio of the total mass of mefensulfuron-methyl and quinclorac acid to the mass of sodium p-chlorophenoxyacetate is (330~510):

1. The warm-season turfgrass is Zoysia japonica. The grassy weeds are one or more of the following: Imperata cylindrica, Crataegus pinnatifida, Setaria viridis, Leymus chinensis, and Barnyardgrass.

2. The application according to claim 1, characterized in that, The application rate of the active ingredient in the herbicide composition or herbicide is 0.0225~0.09 g / m³ of mefensulfuron-methyl. 2 0.0375~0.075 g / m³ of quinclorac acid 2 Sodium p-chlorophenoxyacetate 0.00025 g / m 2 .

3. The application according to claim 1, characterized in that, The application conditions for the herbicidal composition or herbicide are as follows: watering the day before or on a sunny, windless day after rain, during the time period of 9:00-11:00 or 15:00-18:00.

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