Weed control methods

Abstract

To provide a pelargonic acid-based herbicide that is diluted with water for use, wherein the herbicide is stable regardless of whether it is in an on-sale state or a use state, and can be easily diluted by a user with water, offering improved usability.SOLUTION: A water-diluted herbicide composition contains pelargonic acid as a herbicidal active ingredient, at least one cationic surfactant selected from monoalkyl cationic surfactants and dialkyl cationic surfactants, and water. Before diluted with water, the herbicide composition has a viscosity of 20 Pa s.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a herbicidal composition, in particular to a technical field containing pelargonic acid, and more specifically to a herbicidal composition which is used after dilution with water. [Background technology]

[0002] Fatty acids with 6 to 12 carbon atoms, particularly pelargonic acid (common name: Pelargonic acid, IUPAC name: Nonanoic acid), which has 9 carbon atoms, are safe and rapidly acting herbicidal compounds and are widely used around the world (see, for example, Patent Document 1).

[0003] Pelargonic acid is also used as a food additive and is attracting attention as a herbicidal active ingredient with a safe image, and there is a growing demand for herbicides that use pelargonic acid.

[0004] Pelargonic acid is a hydrophobic substance with a solubility in water of 32 ppm (30°C), and the development of a herbicide using pelargonic acid requires technology to solubilize or emulsify pelargonic acid.

[0005] For example, Patent Document 1 discloses a formulation technique in which pelargonic acid is stably present in water as an acid by using water as the main solvent and combining an anionic surfactant and a nonionic surfactant.

[0006] Moreover, Patent Document 2 discloses a technique for emulsifying pelargonic acid using a quaternary ammonium salt as a surfactant.

[0007] On the other hand, Patent Documents 3 and 4 disclose preparations in which the water solubility of pelargonic acid is improved by neutralizing it with an organic base. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2016-190832 A [Patent Document 2] Special Publication No. 5-502216 [Patent Document 3] JP 2013-216643 A [Patent Document 4] JP 2014-91739 A Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, the prior art includes a formulation in which pelargonic acid exists in an acid form in water and is emulsified or solubilized by a surfactant (Patent Documents 1 and 2), and a formulation in which pelargonic acid is neutralized with a basic substance to improve its water solubility (Patent Documents 3 and 4). The former, in which pelargonic acid exists as an acid, is known to exhibit a more rapid herbicidal effect than the latter, and is more desirable in that the user can easily feel the herbicidal effect. However, in the conventional pelargonic acid herbicides emulsified and solubilized by a surfactant, the pelargonic acid may separate under harsh conditions such as long-term storage in a high-temperature environment. Thus, conventional pelargonic acid herbicides have not yet been able to achieve both stability and rapid action.

[0010] By the way, in the field of herbicides, there are dilution-type herbicides that the user dilutes with water when using them. Since these dilution-type herbicides are sold at a higher concentration than the concentration actually used, they are small in weight and volume when sold, and are therefore economical and easy to carry.

[0011] Therefore, there is a demand for dilution-type herbicides of pelargonic acid as well. In such cases, it is required that the herbicide is stable in the state at which it is sold, i.e., in a highly concentrated state, stable even after dilution with water without separation of the liquid, and easy to dilute.

[0012] However, it is technically difficult to emulsify and solubilize pelargonic acid herbicides stably even at normal concentrations, and no diluted herbicides that combine the above-mentioned practical properties are known yet.

[0013] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a pelargonic acid herbicide of the type that is used by diluting with water, which is stable both in the state at the time of sale and the state at the time of use, and which can be easily diluted with water by the user, making it easy to use. [Means for solving the problem]

[0014] In order to achieve the above object, a first aspect of the present disclosure can be based on the premise of a liquid herbicide composition to be diluted with water. The herbicide composition contains pelargonic acid as a herbicidally active ingredient, any one or more cationic surfactants selected from monoalkyl cationic surfactants and dialkyl cationic surfactants, and water. In the herbicide composition, when the concentration of the pelargonic acid is a and the concentration of the cationic surfactant is b, the concentration ratio R=b / a is 0.83 or more and 2.50 or less, the concentration of the pelargonic acid before dilution with water is 38 mass% or less, and the viscosity before dilution with water is set to 20 Pa·s (Pascal seconds) or less.

[0015] According to this configuration, by combining pelargonic acid with a specific cationic surfactant, a stable herbicidal composition is obtained whether it is in a high concentration state before dilution with water or in a concentration state at the time of use after dilution with water. In addition, by setting the viscosity before dilution with water to 20 Pa·s or less, the user can easily dilute it with water, making it highly practical. Furthermore, when sprayed on weeds, for example, the herbicidal effect of pelargonic acid, which is a herbicidal active ingredient, appears quickly.

[0016] In a second aspect of the present disclosure, mixed vesicles are formed in the water by the pelargonic acid and the cationic surfactant after dilution with the water.

[0017] According to this constitution, the dispersion state of pelargonic acid can be stably maintained even after dilution with water, and the composition has excellent immediate herbicidal effect.

[0018] Here, in a herbicide containing pelargonic acid as a herbicidal active ingredient, if the pelargonic acid does not adhere to the surface of weeds when sprayed, it is considered that a sufficient herbicidal effect cannot be obtained. On the other hand, the mixed vesicle-formed pelargonic acid is contained in a self-association body by interacting with a cationic surfactant, and it has not been examined whether the pelargonic acid can adhere to the surface of weeds when sprayed on weeds. Through the examination by the present inventors, it has been confirmed for the first time that a high herbicidal effect is achieved by a mixed vesicle-formed pelargonic acid herbicide composition.

[0019] In other words, by containing any one or any two or more cationic surfactants selected from the group consisting of monoalkyl cationic surfactants and dialkyl cationic surfactants, pelargonic acid is uniformly dispersed and dissolved in water as a self-aggregate of mixed vesicles, and when sprayed, the pelargonic acid that constituted the mixed vesicles adheres to the surface of weeds. As a result, even if the product is left under low or high temperature conditions after being diluted with water, it has excellent stability over time and a high herbicidal effect.

[0020] In a third aspect of the present disclosure, the herbicide composition may be one in which the dilution ratio with water is 5 or more. This configuration makes it possible to keep the weight and volume of the herbicide composition small when sold, while ensuring a sufficient capacity when used.

[0021] In a fourth aspect of the present disclosure, the herbicide composition may have an upper limit of the dilution ratio with water of 25 or less. According to this configuration, a composition having excellent immediate herbicidal properties can be obtained while maintaining the dispersion state of pelargonic acid.

[0022] In a fifth aspect of the present disclosure, the concentration of the pelargonic acid after dilution with water is 1.5% by mass or more and 5.0% by mass or less.

[0023] According to this configuration, if the concentration of pelargonic acid after dilution with water is within this range, vesicle formation after dilution is stable and a sufficient herbicidal effect is obtained.

[0024] In a sixth aspect of the present disclosure, the concentration of the pelargonic acid before being diluted with water is 10% by mass or more.

[0025] In a seventh aspect of the present disclosure, the concentration of the pelargonic acid before being diluted with water is 20% by mass or more and 30% by mass or less.

[0026] This composition further enhances the herbicidal effect of pelargonic acid.

[0027] In an eighth aspect of the present disclosure, the concentration ratio R=b / a is equal to or greater than 1.00 and equal to or less than 2.00.

[0028] That is, by setting the amount of the cationic surfactant relative to the pelargonic acid within the above range, the solution can be stabilized both before and after dilution.

[0029] In a ninth aspect of the present disclosure, a monohydric or polyhydric alcohol having 2 to 6 carbon atoms is contained, and the concentration of the monohydric or polyhydric alcohol before dilution with water is 10 mass % or more.

[0030] In a tenth aspect of the present disclosure, the monohydric or polyhydric alcohol has a concentration of 20% by mass or more before being diluted with water. The alcohol may have 1 to 6 hydroxyl groups.

[0031] According to this configuration, the inclusion of alcohol prevents the viscosity before dilution from becoming too high, and facilitates the stable formation of mixed vesicles after dilution. Effect of the Invention

[0032] As described above, the herbicide composition is stable both in the state at the time of sale and in the state at the time of use, and can be easily diluted with water by the user, making it easy to use. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, the embodiments of the present invention will be described in detail. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0034] The herbicide composition according to the embodiment of the present invention is a liquid herbicide composition that is diluted with water. The herbicide composition that is diluted with water can also be called a dilution type herbicide composition. The herbicide composition contains pelargonic acid as a herbicidal active ingredient, a specific cationic surfactant, and water. The herbicide composition may further contain a specific alcohol as described below.

[0035] The herbicide composition can be stored, for example, in various containers. By storing the herbicide composition in a container, a product used for weed control is formed. This diluted type herbicide composition is used by diluting it with water and then spraying it on weeds. Therefore, at least until it reaches the user, the herbicidal active ingredient is present in the water at a higher concentration than when it is used. If separation or the like occurs in the herbicide composition when it reaches the user, it becomes difficult for the user to appropriately perform operations such as measuring and stirring when diluting with water. Therefore, it is important to be able to store the herbicide composition in a uniform state for a long period of time in stores, warehouses, etc.

[0036] In this regard, as described later, according to the configuration of the present invention, the herbicide composition before dilution with water can be stably stored in a homogeneous state for a long period of time without any change in properties such as separation.

[0037] When a user uses this herbicide composition, the required amount of the herbicide composition is measured out, and water is added to dilute the composition so that the concentration of pelargonic acid is adjusted to a predetermined concentration. The amount of water to be added, i.e., the dilution ratio, is preset and can be written, for example, on the container. The dilution ratio means how many times the amount of the original solution is obtained. For example, if the dilution ratio is 2 times, water is added so that the amount is twice the amount of the original solution. The dilution ratio does not have to be an integer multiple.

[0038] The dilution ratio of the herbicide composition with water can be 5 times or more, and may be 10 times or more, or may be 15 times or more. If the dilution ratio is less than 5 times, it is not preferable because the advantage of making it a concentrated type is reduced. The upper limit of the dilution ratio of the herbicide composition with water can be 25 times or less, and may be 20 times or less, or may be 15 times or less. If the dilution ratio is too high, the concentration of the herbicidal active ingredient in the state before dilution must be extremely high, so that the herbicide composition before dilution becomes unstable and the viscosity becomes too high, making it difficult to dilute the herbicide composition.

[0039] When diluting the herbicide composition with water, for example, a separate dilution container is prepared, and a predetermined amount of the herbicide composition and water are poured into the dilution container to obtain the diluted herbicide composition. The herbicide composition may be poured into the dilution container first, or the water may be poured into the dilution container first. As described above, the herbicide composition before dilution is in a uniform state, so that the user can appropriately perform operations such as measuring and stirring when diluting with water.

[0040] The diluted herbicide composition can be used by directly spraying it on weeds from the dilution container, or it can be transferred to a spraying container separate from the dilution container and sprayed on weeds. The container that holds the diluted herbicide composition may be provided with a shower nozzle with multiple openings. The container that holds the diluted herbicide composition may be provided with a sprayer equipped with a pump mechanism. The container that holds the diluted herbicide composition may be an aerosol container equipped with a valve and a nozzle, and in this case, the herbicide composition according to the present invention is filled into the aerosol container together with a propellant to form an aerosol product.

[0041] However, if the herbicide composition after dilution with water immediately separates, it must be stirred every time it is applied to weeds, resulting in a herbicide that is extremely difficult to use. In this regard, according to the configuration of the present invention, the herbicide composition after dilution with water can stably maintain a homogeneous state for a long period of time without separation, etc. Therefore, even if the herbicide composition has been diluted with water for a long time, it can be applied directly to weeds, thereby realizing a herbicide with extremely high practicality.

[0042] (Pelargonic acid is a herbicidal active ingredient) The herbicidal active ingredient pelargonic acid according to the present embodiment may be used alone or as a major component (e.g., 90% or more) of a mixture containing other fatty acids. When other fatty acids are contained, the herbicidal active ingredient may be one or a mixture of carboxyl fatty acids having a hydrocarbon chain with 8 to 12 carbon atoms, including pelargonic acid.

[0043] In the water after diluting the herbicide composition with water, a mixed vesicle is formed by pelargonic acid and a cationic surfactant. Pelargonic acid is present in the water after diluting the herbicide composition with water by interacting with the cationic surfactant to form a mixed vesicle. That is, the mixed vesicle is a self-assembly in which amphiphilic molecules having both hydrophobicity and hydrophilicity are arranged without gaps to form a spherical shell or a bag shape in water, and since the layer of the self-assembly is a multi-phase, pelargonic acid is uniformly contained, and the pelargonic acid can be stabilized in water for a long time.

[0044] The lower limit of the concentration range of pelargonic acid in the solution after diluting the herbicide composition with water is 1.5% by mass or more, more preferably 2.0% by mass or more. The upper limit of the concentration range of pelargonic acid in the solution after diluting the herbicide composition with water is 5.0% by mass or less, more preferably 4.5% by mass or less. If the concentration range of pelargonic acid in the solution after diluting the herbicide composition with water exceeds the above upper limit, the above-mentioned mixed vesicles are difficult to form, and the formed mixed vesicles are easily broken. In addition, if the concentration range of pelargonic acid is below the above lower limit, the herbicidal effect becomes insufficient and the mixed vesicles are difficult to form.

[0045] The lower limit of the concentration range of pelargonic acid in the herbicide composition before dilution with water is 10% by mass or more, more preferably 20% by mass or more. The upper limit of the concentration range of pelargonic acid in the herbicide composition before dilution with water is 38% by mass or less, more preferably 30% by mass or less. If the concentration range of pelargonic acid in the herbicide composition before dilution with water exceeds the above upper limit, the stability during storage is deteriorated, and it is difficult to form mixed vesicles after dilution with water. In addition, if the concentration range of pelargonic acid is below the above lower limit, the herbicidal effect becomes insufficient when the dilution ratio is, for example, 5 times or 10 times.

[0046] (cationic surfactant) In order to form the mixed vesicle in water after diluting the herbicide composition with water, the specific cationic surfactant is required. The specific cationic surfactant is any one or any two or more cationic surfactants selected from a group of surfactants consisting of a plurality of surfactants classified as monoalkyl cationic surfactants and a plurality of surfactants classified as dialkyl cationic surfactants. The specific cationic surfactant may be only a monoalkyl cationic surfactant or only a dialkyl cationic surfactant. The specific cationic surfactant may contain a monoalkyl cationic surfactant and a dialkyl cationic surfactant. In this case, it may contain one monoalkyl cationic surfactant and two or more dialkyl cationic surfactants, or it may contain two or more monoalkyl cationic surfactants and one dialkyl cationic surfactant.

[0047] Examples of monoalkyl cationic surfactants include lauryl trimethyl ammonium chloride, myristyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, alkyl (C12-C16) trimethyl ammonium chloride, and alkyl (C16-C18) trimethyl ammonium chloride.

[0048] Examples of the dialkyl cationic surfactant include dioctyl dimethyl ammonium chloride, didecyl dimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, dialkyl (C12-C18) dimethyl ammonium chloride, didecyl dimethyl ammonium chloride, dialkyl dimethyl ammonium chloride, and dialkyl (C16-18) dimethyl ammonium chloride.

[0049] The lower limit of the concentration range of the specific cationic surfactant after dilution is 1.8% by mass or more, more preferably 2.5% by mass or more. The upper limit of the concentration range of the cationic surfactant after dilution is 18.0% by mass or less, more preferably 16.0% by mass or less. If the concentration range of the specific cationic surfactant before dilution is outside the above range, it becomes difficult to form mixed vesicles.

[0050] The upper limit of the concentration range of the specific cationic surfactant before dilution can be 50.0% by mass, and the lower limit can be 10.0% by mass. This allows mixed vesicles to be formed in the water after dilution. The herbicide composition before dilution can also be called a concentrated herbicide composition.

[0051] (Concentration ratio of pelargonic acid to cationic surfactant R=b / a) In addition, when the concentration of pelargonic acid is a and the concentration of the specific cationic surfactant is b, the concentration ratio R of the specific cationic surfactant to pelargonic acid can be expressed by the following formula 1.

[0052] R=b / a formula 1

[0053] The lower limit of R is 0.83 or more, more preferably 1.00 or more. The upper limit of R is 2.50 or less, more preferably 2.00 or less. If the value of R is out of the above range, it becomes difficult to form mixed vesicles in water after diluting the herbicide composition with water. Since R is the concentration ratio of pelargonic acid and cationic surfactant, it has the same value before and after diluting the herbicide composition with water.

[0054] However, in the herbicide composition before dilution with water, mixed vesicles of pelargonic acid and cationic surfactant may not be formed. This is because, before dilution with water, pelargonic acid and cationic surfactant may be at high concentrations and may not be suitable for forming mixed vesicles. Even in this case, by setting the concentrations of pelargonic acid and cationic surfactant within the above range, the herbicide composition before dilution with water can form a uniform layer that is transparent or translucent as a whole. This state is considered to be a state in which pelargonic acid is in a solubilized state or a state close to it due to the high concentration of cationic surfactant, and is a thermodynamically stable state. As a result, the herbicide composition before dilution with water can be stably stored in a uniform state without separation or the like for a long period of time.

[0055] (Monohydric or polyhydric alcohol) In order to ensure the formation of the mixed vesicles in water after diluting the herbicide composition with water, it is preferable that the herbicide composition contains a specific alcohol. The specific alcohol is a monohydric or polyhydric alcohol, and is preferably an alcohol having 2 to 6 carbon atoms and 1 to 6 hydroxyl groups. Examples of such alcohols include ethyl alcohol, propyl alcohol, isopropyl alcohol, 1,3 butylene glycol, propylene glycol, dipropylene glycol, glycerin, sorbitol, etc.

[0056] By using the specific alcohol, the mixed vesicles are more reliably formed in water after dilution. The lower limit of the alcohol concentration range before dilution with water is 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or more. The upper limit of the alcohol concentration range before dilution with water is 35% by mass or less, and more preferably 30% by mass or less. If the alcohol concentration range is outside the above range, mixed vesicles are less likely to be formed in water after dilution, or the formed mixed vesicles are more likely to break, resulting in reduced stability.

[0057] (Other ingredients) The water contained in the herbicide composition before dilution may be purified water or ion-exchanged water. The herbicide composition before dilution may contain, for example, a preservative. Examples of the preservative include, but are not limited to, isothiazolinone derivatives.

[0058] In addition, the herbicide composition before dilution may contain a pest control component (insecticide component). Examples of the pest control component include, but are not limited to, pyrethroid insecticides, neonicotinoid insecticides, and diamide insecticides. Examples of pyrethroid insecticides include transfluthrin, pyrethrin, allethrin, phthalthrin, tetramethrin, prallethrin, fenothrin, tralomethrin, cyfluthrin, resmethrin, permethrin, empenthrin, cyphenothrin, imiprothrin, fenpropathrin, fenvalerate, etofenprox, and silafluofen. Examples of neonicotinoid insecticides include imidacloprid, nitenpyram, acetamiprid, thiamethoxam, clothianidin, and dinotefuran. Examples of diamide insecticides include flubendiamide, chlorantraniliprole, and cyantraniliprole. One or more of these can be used in combination. The concentration of the pest control component after dilution can be 0.01% by mass or more and 0.10% by mass or less.

[0059] (Viscosity of Herbicide Composition) The viscosity of the herbicide composition before dilution with water is set to 20 Pa·s or less. The viscosity of the herbicide composition before dilution with water can also be set to 18 Pa·s or 15 Pa·s or less. The lower limit of the viscosity of the herbicide composition before dilution with water can be set to 10.0 mPa·s or more. The viscosity of the herbicide composition can be adjusted by the concentration of pelargonic acid, the concentration of the cationic surfactant, the concentration of the specific alcohol, etc. By setting the viscosity of the herbicide composition before dilution with water to 20 Pa·s or less, it is easy to mix with water when the user dilutes it with water, making the dilution work easier.

[0060] The viscosity of the herbicidal composition in the examples described below was measured using a single cylinder rotational viscometer (TVB-10, manufactured by Toki Sangyo Co., Ltd.). The method for measuring viscosity using a single cylinder rotational viscometer is specified as a standard in JIS Z8803.

[0061] (Method of producing herbicidal composition) An example of a method for producing a herbicide composition will be described. First, purified water heated to 70°C is prepared. The specific cationic surfactant, pelargonic acid, and alcohol are dissolved in this purified water. If a pest control component is contained, the pest control component is also dissolved. After that, the mixture is cooled to room temperature, and a preservative is added. The obtained herbicide composition contains a high concentration of pelargonic acid, but is stored in a container as it is. The method of use is as described above. EXAMPLES

[0062] Examples of the present invention will be described below, but the present invention should not be construed as being limited to these examples.

[0063] [Table 1]

[0064] Table 1 shows the composition of the herbicide composition according to Examples 1 to 11 of the present invention. The concentration of pelargonic acid before dilution of the herbicide composition of Examples 1 to 11 is 10% by mass or more and 38% by mass or less. The concentration of monoalkyl cationic surfactant before dilution of the herbicide composition of Examples 1 to 11 is 5% by mass or more and 25% by mass or less. The concentration of dialkyl cationic surfactant before dilution of the herbicide composition of Examples 1 to 11 is 5% by mass or more and 50% by mass or less. The concentration of alcohol before dilution of the herbicide composition of Examples 1 to 11 is 10% by mass or more and 20% by mass or less. The concentration of preservative before dilution of the herbicide composition of Examples 1 to 11 is 0.02% by mass. The viscosity before dilution of the herbicide composition of Examples 1 to 11 is 10.0 mPa·s or more and 12.9 Pa·s or less. The balance is purified water. Furthermore, the preservative has almost no effect on the herbicidal effect or viscosity.

[0065] In the herbicidal compositions of Examples 1 to 11, the concentration ratio R of the concentration b of the cationic surfactant to the concentration a of the herbicidal active ingredient is set in the range of 0.83 or more and 2.50 or less.

[0066] (Appearance evaluation) After preparing the samples of the herbicidal compositions of Examples 1 to 11, they were immediately placed in 100 ml glass bottles and visually evaluated for appearance at room temperature (RT). The same evaluation was also carried out for the comparative examples described below. Transparent: transparent liquid Cloudy: Cloudy liquid Separated: A liquid in which the components have been separated

[0067] The appearance was transparent in all of Examples 1 to 11. This was the same even when a pest control ingredient was mixed in.

[0068] (Stability evaluation) Next, the results of the stability test will be described. In the stability test, samples of the herbicide compositions of Examples 1 to 11 were placed in 100 ml glass bottles and stored for one month in thermostatic chambers at room temperature (RT), 5°C, and 50°C. The condition (appearance) of the herbicide composition after one month of storage was visually evaluated, and the stability was evaluated according to the following criteria. The comparative examples described below were also evaluated in the same manner. ○: No separation (single homogeneous phase). ×: Complete separation into two phases.

[0069] As shown in Table 1, the herbicidal compositions of Examples 1 to 11 were rated "○" at all temperatures of "RT", "5°C" and "50°C", and maintained a homogeneous single phase. In other words, the herbicidal compositions in a state before dilution with water can be stably stored for a long period of time. This is the same even when a pest control component is mixed.

[0070] (Evaluation after dilution) The herbicidal compositions of Examples 1 to 11 are respectively diluted 5-fold, 10-fold, 15-fold, 20-fold, and 25-fold. In the column "Pelargonic acid concentration after dilution" in Table 1, "◯" indicates an example in which mixed vesicles are stably formed in water after dilution with water, "×" indicates an example in which mixed vesicles are not stably formed in water after dilution with water, and "△" indicates an example in which the concentration of pelargonic acid is too low after dilution with water, making it unsuitable as a herbicide.

[0071] Whether or not mixed vesicles are formed can be judged as follows. That is, after preparing samples of the herbicidal compositions of Examples 1 to 11, they are placed in 100 ml glass bottles (sample bottles), and the glass bottles are placed in a box having orthogonal polarizing plates (crossed Nicols) at room temperature (RT). Whether or not mixed vesicles are formed can be judged by shining light on the sample bottle from outside the polarizing plate box and visually observing the state of the light that passes through the sample bottle through the polarizing plate. The same evaluation was also performed for the comparative examples described later.

[0072] In addition, in order to confirm the stability of the diluted herbicide composition, a test similar to the above stability test was carried out on the diluted herbicide composition. As a result, in the cases where mixed vesicles were formed, i.e., the cases marked with "○", separation or changes in properties were not observed even when stored for an extremely long period of time, such as one month, in an extremely wide temperature range of 5°C to 50°C. On the other hand, in the cases where mixed vesicles were not formed, i.e., the cases marked with "×", changes in properties such as separation were observed. From the above, it can be seen that the diluted herbicide composition is extremely stable due to the formation of mixed vesicles after dilution. The same results are obtained even if no preservative is contained. The same is true even if a pest control component is mixed.

[0073] Next, comparative examples 1 to 5 will be described.

[0074] [Table 2]

[0075] Comparative Examples 1 to 3 are examples in which the mixed vesicles were not formed in the water after dilution with water. Comparative Example 4 was cloudy in appearance. Comparative Example 5 was separated in appearance.

[0076] (Weed control test) Next, the herbicidal test will be described. Table 3 shows the formulation of Comparative Example 6.

[0077] [Table 3]

[0078] Comparative Example 6 is an example containing pelargonic acid and triethanolamine, and the content of pelargonic acid is 3.0% by mass.

[0079] The herbicidal test method is as follows. First, wood sorrel, crabgrass, and green foxtail were prepared as test weeds. Each weed was transplanted into a pot, and the herbicides of Example 9 (diluted 10 times) and Comparative Example 6 were sprayed evenly over each weed using a hand sprayer with a discharge volume of 1 ml. The 10-fold dilution of Example 9 resulted in a pelargonic acid content of 3.0% by mass.

[0080] The pots were then placed in an artificial climate chamber (temperature 25°C, humidity 60%) and the state of the weeds was recorded using the interval photography function of a camera. The results are shown in Table 4.

[0081] [Table 4]

[0082] In Example 9, the time until wood sorrel, crabgrass, and green foxtail began to wither was significantly shorter than in Comparative Example 6. The time until withering was also significantly shorter in Example 9. In particular, while crabgrass could not be completely killed in Comparative Example 6, it was possible to completely kill crabgrass in Example 9. The formulations of the other Examples other than Example 9 can also provide similar herbicidal effects, although the time required may vary slightly.

[0083] (Effects of the embodiment) As described above, according to this embodiment, by combining pelargonic acid with a specific cationic surfactant, a herbicidal composition that is stable for a long period of time can be obtained, whether it is in a high concentration state before dilution with water or in a concentration state at the time of use after dilution with water. In addition, by setting the viscosity before dilution with water to 20 Pa s or less, the user can easily dilute it with water, and the composition is highly practical. In addition, when sprayed on weeds, for example, the herbicidal effect of pelargonic acid, which is a herbicidal active ingredient, appears quickly.

[0084] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0085] As described above, the herbicidal composition according to the present invention can be used against weeds such as wood sorrel, crabgrass, and green foxtail.

Claims

1. A weeding method comprising the steps of: Pelargonic acid, a herbicidal active ingredient; one or more cationic surfactants selected from monoalkyl cationic surfactants and dialkyl cationic surfactants; and water, When the concentration of the pelargonic acid is a and the concentration of the cationic surfactant is b, the concentration ratio R = b / a is 0.83 or more and 2.50 or less; The concentration of the pelargonic acid is 38% by mass or less, A liquid herbicide composition having a viscosity of 20 Pa·s or less is prepared, The herbicidal method comprises diluting the liquid herbicidal composition with water, forming mixed vesicles of the pelargonic acid and the cationic surfactant in the water after dilution with water, and spraying the liquid in which the mixed vesicles are formed on weeds.

2. The weeding method according to claim 1, The weed-killing method, wherein the dilution ratio with water is 5 times or more.

3. The weeding method according to claim 1 or 2, The herbicidal method according to claim 1, wherein the upper limit of the dilution ratio with water is 25 times or less.

4. The weeding method according to any one of claims 1 to 3, The herbicidal method according to claim 1, wherein the concentration of the pelargonic acid after dilution with water is 1.5% by mass or more and 5.0% by mass or less.

5. The weed control method according to any one of claims 1 to 4, A herbicidal method, wherein the concentration of the pelargonic acid before dilution with water is 10 mass% or more.

6. The weeding method according to claim 5, A herbicidal method, wherein the concentration of the pelargonic acid before dilution with water is 20% by mass or more and 30% by mass or less.

7. The weeding method according to any one of claims 1 to 6, A herbicidal method, wherein the concentration ratio R = b / a is 1.00 or more and 2.00 or less.

8. The weeding method according to any one of claims 1 to 7, The liquid herbicide composition before being diluted with water contains a monohydric or polyhydric alcohol having 2 to 6 carbon atoms, A herbicidal method, wherein the concentration of the monohydric or polyhydric alcohol before dilution with water is 10 mass% or more.

9. The weeding method according to claim 8, A herbicidal method, wherein the concentration of the monohydric or polyhydric alcohol before dilution with water is 20 mass% or more.

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