Insecticide composition and pest control method

Abstract

To provide a composition that contains fatty acids such as pelargonic acid as an active ingredient and uses water as a solvent, enabling the pelargonic acid or the like to be stably dispersed in water, and to provide a pest control method that allows for early knockdown of pests.SOLUTION: An insecticidal composition contains a C8-12 fatty acid (a), a cationic surfactant (b), and water.SELECTED DRAWING: None

Description

Technical Field

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[0001] The present disclosure relates to an insecticidal composition for killing pests such as flies and a pest control method for knocking down pests.

Background Art

[0002] For example, insecticidal compositions using synthetic insecticides are known. However, there are also needs among natural-oriented users not to use synthetic insecticides. Therefore, if pest control can be achieved with natural-derived components, particularly components with a high safety image such as those used in food additives, the above needs can also be met.

[0003] In this regard, for example, Patent Document 1 discloses a pest control agent containing pelargonic acid and its salts as active ingredients, and it is known that pelargonic acid, which is a food additive, has a certain pest control effect.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, pelargonic acid is a hydrophobic substance with a solubility in water of 32 ppm (30°C) and cannot be dissolved in water and formulated as it is. In this regard, Patent Document 1 describes, as specific examples using pelargonic acid, examples using organic solvents such as acetone and kerosene, and examples of dispersion in water using a nonionic surfactant (Tween 80).

[0006] However, using organic solvents raises concerns about flammability and does not meet the needs of users who prefer natural materials. Therefore, the inventors of this invention considered formulation using water as a solvent and nonionic surfactants, but found that it was extremely difficult to stably emulsify or solubilize pelargonic acid.

[0007] Therefore, the object of the present invention is to provide a composition in which pelargonic acid or the like is used as an active ingredient and water is used as a solvent, and which allows pelargonic acid or the like to be stably dispersed in water, and a pest control method that can knock down pests at an early stage. [Means for solving the problem]

[0008] As mentioned above, conventional technologies use nonionic surfactants as dispersants. This is because nonionic surfactants are generally considered to have excellent emulsifying properties. On the other hand, cationic surfactants, for example, are said to have antistatic and bactericidal properties and are used in fabric softeners and hair rinses, but their application in the field of insecticides has not progressed.

[0009] The inventors of this invention have discovered that higher fatty acids such as pelargonic acid can be dispersed in water by incorporating a cationic surfactant. They have further discovered that spraying this composition on pests provides an insecticidal effect, and that certain fatty acids also exhibit knockdown activity, thus completing the present invention. Moreover, they have found that in certain cases, the cationic surfactant and higher fatty acids such as pelargonic acid form mixed vesicles in water, resulting in an extremely stable composition.

[0010] In other words, the insecticidal composition according to one aspect of the present disclosure contains a fatty acid (a) having 8 to 12 carbon atoms, a cationic surfactant (b), and water, so that the fatty acid can be stably dispersed in water, and insects can be killed by spraying the insecticidal composition on pests or the like.

[0011] In other embodiments of this disclosure, the insecticidal composition may be one in which a mixed vesicle of the fatty acid (a) and the cationic surfactant (b) is formed in water. This makes it possible to obtain an insecticidal composition with excellent long-term stability.

[0012] In other aspects of this disclosure, the concentration ratio (b) / (a) of the cationic surfactant (b) to the fatty acid (a) can be 0.8 or more.

[0013] In other embodiments of this disclosure, the concentration of the fatty acid (a) can be 8% by mass or less.

[0014] In other embodiments of this disclosure, the cationic surfactant (b) may include monoalkyl cationic surfactants and dialkyl cationic surfactants.

[0015] By using the above composition, mixed vesicles of fatty acids and cationic surfactants are more easily formed, thereby improving stability over time.

[0016] In other aspects of this disclosure, the fatty acid (a) may be caprylic acid or pelargonic acid. This can provide not only a lethal effect but also a knockdown effect on pests, and therefore it is also possible to provide a pest control method that knocks down pests by spraying an insecticide composition containing caprylic acid or pelargonic acid onto them. [Effects of the Invention]

[0017] As explained above, since it contains fatty acids with 8 to 12 carbon atoms, a cationic surfactant, and water, the fatty acids can be stably dispersed in water when water is used as the solvent. Furthermore, it can provide a pest control method that can knock down pests at an early stage. [Modes for carrying out the invention]

[0018] Hereinafter, 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.

[0019] The insecticidal composition according to the embodiment contains a fatty acid (a) having 8 to 12 carbon atoms, a cationic surfactant (b), and water, and is a liquid composition in which the fatty acid (a) is dispersed in water.

[0020] <Fatty acid (a)> Examples of the fatty acid (a) include pelargonic acid, caprylic acid, lauric acid, etc. Among these, only any one kind or any combination of plural kinds can also be used.

[0021] <Cationic surfactant (b)> As the cationic surfactant (b), one or both of a monoalkyl cationic surfactant and a dialkyl cationic surfactant can be used. Examples of the monoalkyl cationic surfactant 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, alkyl (C16 - C18) trimethyl ammonium chloride, etc.

[0022] 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, dialkyl (C16 - 18) dimethyl ammonium chloride, etc.

[0023] As the cationic surfactant, it may be only a monoalkyl cationic surfactant or only a dialkyl cationic surfactant. Also, as the cationic surfactant, it may contain a monoalkyl cationic surfactant and a dialkyl cationic surfactant. In this case, it may contain one kind of monoalkyl cationic surfactant and two or more kinds of dialkyl cationic surfactants, or may contain two or more kinds of monoalkyl cationic surfactants and one kind of dialkyl cationic surfactant.

[0024] <Water> Water is a component that serves as a solvent for fatty acids. The water that can be used is not particularly limited, and examples include purified water, ion-exchanged water, tap water, hot spring water, deep ocean water, plant distilled water, and the like.

[0025] <Concentration ratio of fatty acid (a) to cationic surfactant (b)> The concentration ratio (b) / (a) of the cationic surfactant (b) to the fatty acid (a) is set to 0.6 or more. The lower limit of the concentration ratio (b) / (a) is more preferably 0.8 or more, and can also be set to 0.9 or more. The upper limit of the concentration ratio (b) / (a) can be set to, for example, 10.0 or less, and can also be set to 8.0 or less.

[0026] <Concentration of fatty acid (a)> The concentration of the fatty acid (a) is set to 8% by mass or less. The concentration of the fatty acid (a) can also be set to 7% by mass or less. When the concentration of the fatty acid exceeds the above range, it becomes difficult to form the mixed vesicles described later, and the viscosity of the insecticidal composition becomes high, making it unsuitable for spraying or spreading. The lower limit of the concentration of the fatty acid (a) can be set to, for example, 1% by mass or more. The lower limit of the concentration of the fatty acid (a) can be set to, for example, 2% by mass or more.

[0027] <Concentration of cationic surfactant (b)> The concentration of cationic surfactant (b) is set to 1% by mass or higher. The concentration of cationic surfactant (b) can also be set to 1.5% by mass or higher. The upper limit of the concentration of cationic surfactant (b) is set to 20% by mass or lower. The upper limit of the concentration of cationic surfactant (b) can also be set to 19% by mass or lower.

[0028] <Other ingredients> The insecticidal composition may also contain other components, such as alcohols and preservatives. The alcohol is preferably a monohydric or polyhydric alcohol with 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, and sorbitol. Using these specific alcohols ensures more reliable formation of mixed vesicles in water.

[0029] Examples of preservatives include isothiazolinone derivatives, but these are components that do not affect the insecticidal efficacy.

[0030] <Formation of mixed vesicles> The insecticidal composition according to this embodiment, by combining a fatty acid (a) and a cationic surfactant (b) as described above, can form mixed vesicles of the fatty acid (a) and cationic surfactant (b) in water. In this case, the fatty acid, such as pelargonic acid, interacts with the cationic surfactant in water to form mixed vesicles. These mixed vesicles are self-assemblies in which amphiphilic molecules, which are both hydrophobic and hydrophilic in water, are arranged without gaps to form a spherical shell or sac-like structure. Because the layers of the self-assemblies are in multiple phases, the fatty acid is uniformly contained, allowing for long-term stabilization of the fatty acid in water.

[0031] However, from the standpoint of insecticidal effect and knockdown activity, the formation of mixed vesicles is not essential. In other words, even if mixed vesicles are not formed, fatty acids such as pelargonic acid can be temporarily dispersed in water by cationic surfactants.

[0032] <Method for producing insecticide compositions> An example of a method for producing an insecticidal composition is described below. First, purified water heated to, for example, 70°C is prepared. The specific cationic surfactant, fatty acid, and alcohol are dissolved in this purified water. After cooling to room temperature, a preservative is added.

[0033] <Pest Control Methods> The pest control method according to this embodiment is a method of knocking down pests by spraying or scattering an insecticidal composition onto them. In this method, the fatty acid is preferably caprylic acid or pelargonic acid. That is, first, the insecticidal composition is placed in a spray container (not shown), such as a spray bottle or aerosol container. Then, the spray nozzle of the spray container is pointed towards the pest and the spray button or trigger is operated, causing the insecticidal composition to be ejected from the nozzle and adhere to the pest. Alternatively, for example, the insecticidal composition may be placed in a shower container and the shower container is tilted to spray it onto the pest. As will be described later, pests to which the insecticidal composition adheres are knocked down quickly. The target pest is not particularly limited, but for example, it can be a fly, in which case it is a fly control method.

[0034] <Examples and Comparative Examples> Examples 1-4 and Comparative Example 1 are shown in Table 1. After preparing the samples for the examples and comparative examples, they were placed in 100 ml glass bottles and visually evaluated at room temperature (RT).

[0035] Transparent gel: Transparent gel Transparent: Transparent liquid Translucent: A translucent liquid Cloudy: A cloudy liquid

[0036] Furthermore, each sample was placed in a 100 ml glass bottle and placed in a box with orthogonal polarizing plates (crossed nicols) at room temperature (RT). Light was then shone onto the sample bottle from outside the polarizing plate box, and the presence or absence of mixed vesicle formation was evaluated by visually observing the pattern of light passing through the sample bottle via the polarizing plates.

[0037] ○: Contains mixed vesicles ×: No mixed vesicles

[0038] As shown in Table 1, vesicles were formed in the water in Examples 1-3, but not in Example 4 or Comparative Example 1.

[0039] [Table 1]

[0040] Examples 5 to 24 are shown in Table 2. In Examples 5 to 24, vesicles are formed in the water.

[0041] [Table 2]

[0042] Comparative Examples 2-5 are shown in Table 3. In Comparative Examples 2-5, no vesicles were formed in the water. Comparative Examples 2-5 are designated as "comparative examples" in order to be compared with Examples 5-24 in terms of the presence or absence of vesicle formation, but as will be described later, the knockdown effect of the present invention can be obtained even if vesicles are not formed in the water.

[0043] [Table 3]

[0044] <Stability over time> Next, we will explain the results of the stability tests. In Tables 2 and 3, "RT (Room Temperature)" refers to the case where the product was stored at room temperature for one month immediately after manufacturing, "5°C" refers to the case where the product was stored at 5°C for one month immediately after manufacturing, and "50°C" refers to the case where the product was stored at 50°C for one month immediately after manufacturing.

[0045] ○: No separation (uniform single phase).

[0046] ×: Completely separated into two phases.

[0047] As shown in Table 2, in Examples 5-24, where vesicles were formed in the water, the translucent state immediately after production was maintained without separation even after one month. On the other hand, in Comparative Examples 2-5 shown in Table 3, vesicles were not formed, and the mixture was either cloudy or a transparent gel immediately after production. Although the fatty acids were initially dispersed in the water, the stability was poor, and separation occurred, especially after one month of storage at 50°C. Furthermore, in Comparative Examples 3 and 4, gelling occurred immediately after production, making them unsuitable for use by spraying or other applications. From the above, it can be seen that the formation of vesicles allows fatty acids to be dispersed in water, and that a dispersed state suitable for use (spraying or other applications) of the insecticidal composition can be stably maintained over a long period of time.

[0048] <Knockdown test> Next, we will explain the knockdown test. Knockdown refers to a state in which an insect is lying on its back and unable to move normally. First, the test method is as follows: an 8 cm diameter glass ring is prepared. The test insect is a housefly. Ten test insects are placed in the glass ring and sealed with a mesh net, and four of these are prepared (Example 1, Example 2, Example 4, Comparative Example 1). The compositions of Example 1, Example 2, Example 4, and Comparative Example 1 are sprayed once into each glass ring from a distance of 20 cm from each mesh net using a hand sprayer. Time measurement starts after spraying, and the time required for 50% of the test insects to be knocked down (KT50: 50% knockdown time) is calculated. A smaller value indicates a faster effect. The average time obtained from three repeated tests is shown in Table 4.

[0049] [Table 4]

[0050] As shown in Table 4, an immediate knockdown effect was obtained in the examples where pelargonic acid (Examples 2 and 4) or caprylic acid (Example 1) was dispersed in water with a cationic surfactant, but no knockdown effect was obtained in Comparative Example 1, which used only a cationic surfactant. Furthermore, in the case of pelargonic acid alone, the spray test could not be performed because the pelargonic acid did not disperse in water. The same was true for caprylic acid alone.

[0051] In other words, it is possible to create a sprayable, water-based liquid composition that provides a knockdown effect without using synthetic insecticides by combining fatty acids and cationic surfactants. Furthermore, as can be seen from Example 4, a knockdown effect can be obtained even if vesicles are not formed. In addition, since vesicles are formed in Examples 1 and 2, they are extremely practical in that they have high stability over time. Although Example 4, in which vesicles are not formed, may separate into two phases during long-term storage, even in this case, it can be sprayed by shaking the container to redisperse the fatty acids in water.

[0052] <Lethal Test> Next, we will describe the lethal test. A test system similar to the knockdown test was prepared. The compositions of Example 1, Example 2, Example 3, and Example 4 were sprayed once into each glass ring from a distance of 20 cm from each mesh net using a hand sprayer. Table 5 shows the lethality of the test insects 24 hours after spraying.

[0053] [Table 5]

[0054] As shown in Table 5, in all of Examples 1 to 4, in which fatty acids were dispersed with a cationic surfactant, an insecticidal effect against houseflies was obtained.

[0055] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0056] As described above, the present invention can be used, for example, to kill pests such as flies.

Claims

1. Fatty acids with 8 to 12 carbon atoms (a), Cationic surfactant (b) and Water and, Includes, The cationic surfactant (b) includes a monoalkyl cationic surfactant or a dialkyl cationic surfactant. The concentration ratio (b) / (a) of the cationic surfactant (b) to the fatty acid (a) is 0.8 or more. An insecticidal composition in which a mixed vesicle of the fatty acid (a) and the cationic surfactant (b) is formed in water.

2. The insecticidal composition according to claim 1, An insecticidal composition wherein the concentration of the fatty acid (a) is 8% by mass or less.

3. The insecticidal composition according to claim 1, The insecticidal composition wherein the fatty acid (a) is caprylic acid or pelargonic acid.

4. A method for controlling pests by spraying the insecticidal composition described in claim 1 onto the pests, thereby knocking down the pests.

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