Peracetic acid preparation for sterilizing grain seeds, method for sterilizing grain seeds using the peracetic acid preparation, and method for controlling diseases.

Abstract

To provide an acetic peracid formulation including, acetic peracid, acetic acid, and hydrogen peroxide, to provide a composition of an optimal acetic peracid formulation in aspects of sterilization activity and crop injury to plants, as the acetic peracid formulation used for sterilization treatment for grain seeds such as rice plants, and to provide a sterilization method for grain seeds using the same, and a disease control method for preventing, bacterial diseases and damages and diseases caused by filamentous fungus.SOLUTION: There is provided an acetic peracid formulation used for sterilization treatment for grain seeds including, as an active ingredient, 0.01 mass% to 16 mass% of acetic peracid, a mass ratio of the acetic acid and the acetic peracid is: acetic acid / acetic peracid=1.0-3.1, and a mass ratio of the hydrogen peroxide and the acetic peracid is: hydrogen peroxide / acetic peracid=0.6-3.1.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a peracetic acid preparation for treating cereal seeds against bacteria and a method for treating cereal seeds against bacteria using the peracetic acid preparation, as well as a method for controlling diseases.

Background Art

[0002] Major cereals in Japan include rice, wheat, barley, etc. Among them, in the seedling raising stage of rice (paddy rice), in order to prevent seed-borne diseases such as bakanae disease and rice blast, it is common practice to perform a bactericidal treatment on seeds before germination. Conventionally, methods for sterilizing (disinfecting) seeds include chemical pesticides, hot water treatment by immersing in hot water, or control methods using microbial pesticides, etc., but they have problems such as safety, environmental aspects, problems with drug-resistant bacteria, and inconvenience in operation (Patent Documents 1, 2, Non-Patent Document 1, etc.).

[0003] On the other hand, in recent years, attempts have been made to apply peracetic acid preparations to the agricultural field (Patent Documents 3 to 8). A peracetic acid preparation uses peracetic acid formed by appropriately mixing hydrogen peroxide and acetic acid through their chemical equilibrium reaction, and contains peracetic acid, hydrogen peroxide, acetic acid, and water. It is more effective than hydrogen peroxide, which has been used for bactericidal purposes due to its oxidizing action, against highly resistant spores. It does not have a reduced bactericidal power like chlorine even in the presence of organic substances, and has characteristics such as being less likely to produce drug-resistant bacteria due to its bactericidal mechanism that irreversibly oxidizes and modifies essential biological molecules such as enzymes and DNA. Furthermore, since the peracetic acid preparation becomes water, oxygen, and acetic acid (salt) that is easily biodegradable over time or by pH adjustment, etc., it is considered a bactericidal and disinfectant that is easy to handle in terms of the environment and health. Also, peracetic acid preparations are approved as food additives for sterilizing meat, chicken, and vegetables.

[0004] Specifically, methods have been reported such as a method for controlling rice seed-borne diseases by immersing rice seeds in an appropriate concentration of peracetic acid before soaking or before and after germination (Patent Document 3), a method for using peracetic acid in an appropriate concentration range when germinating rice seeds (Patent Document 5), a method for using a peracetic acid preparation in an appropriate concentration range for a practical treatment time (Patent Document 6), a method for controlling bacterial diseases such as tomato bacterial wilt by drenching the soil with peracetic acid (Patent Document 3), a method that shows control effects against bacterial diseases such as citrus canker and fungal diseases such as strawberry powdery mildew (Patent Document 7), and a method for suppressing storage diseases caused by fungi in fruits such as Satsuma mandarins and bell peppers (Patent Document 8). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2006-50982 [Patent Document 2] Japanese Patent Publication No. 2013-14573 [Patent Document 3] Japanese Patent Application Publication No. 7-258005 [Patent Document 4] Special Publication No. 2005-514169 [Patent Document 5] Japanese Patent Publication No. 2016-5 [Patent Document 6] Japanese Patent Publication No. 2017-195798 [Patent Document 7] Japanese Patent Publication No. 2020-55808 [Patent Document 8] International Publication No. 2019 / 087972 [Non-patent literature]

[0006] [Non-Patent Document 1] "Plant Protection Course, Group 3 - Diseases," edited by the Editorial Committee of the same book, published by the Japan Plant Protection Association, February 2010, pp. 111-163. [Overview of the project] [Problems that the invention aims to solve]

[0007] There is no existing knowledge regarding the optimal composition of the three components (peracetic acid, acetic acid, and hydrogen peroxide) for agricultural peracetic acid formulations. The desired performance of agricultural peracetic acid formulations is to possess effective fungicidal activity while avoiding phytotoxicity to plants. This invention aims to find the optimal composition of a peracetic acid formulation containing peracetic acid, acetic acid, and hydrogen peroxide for the sterilization treatment of grain seeds such as rice, from the viewpoint of fungicidal activity and phytotoxicity to plants. Furthermore, it aims to provide a method for sterilizing grain seeds using this peracetic acid formulation, as well as a method for controlling diseases such as bacterial diseases and filamentous fungi. [Means for solving the problem]

[0008] The present inventors have prepared a peracetic acid preparation containing peracetic acid, acetic acid, and hydrogen peroxide as a peracetic acid preparation for sterilizing grain seeds, and have found a peracetic acid preparation that has effective sterilizing activity and does not cause phytotoxicity to plants. They have also developed a method for sterilizing grain seeds and a method for controlling diseases using this peracetic acid preparation. In other words, the gist of the present invention is as follows.

[0009] 1. A peracetic acid preparation containing 0.01% to 16% by mass of peracetic acid as an active ingredient, The mass ratio of acetic acid to peracetic acid is acetic acid / peracetic acid = 1.0 to 3.1, and The mass ratio of hydrogen peroxide to peracetic acid is hydrogen peroxide / peracetic acid = 0.6 to 3.1. A peracetic acid preparation for sterilizing grain seeds.

[0010] 2. A method for sterilizing grain seeds by diluting the peracetic acid preparation 100 to 1000 times and using it as a pre-treatment before soaking.

[0011] 3. A method for sterilizing grain seeds by diluting the peracetic acid preparation 100 to 1000 times and using it as a treatment during germination.

[0012] 4. A method for sterilizing grain seeds, characterized by immersion treatment, spraying treatment, or soil treatment using the peracetic acid preparation.

[0013] 5. The above-mentioned grain seed A method for controlling bacterial or fungal diseases of cereal seeds, using a sterilization treatment method.

[0014] 6. A method for controlling bacterial diseases of cereal seeds, wherein the bacterial disease is bakanae disease, brown stripe disease or seedling blight bacterial disease.

[0015] 7. A method for controlling fungal diseases of cereal seeds, wherein the fungal disease is bakanae disease, rice blast or sesame leaf blight.

Effect of the Invention

[0016] The peracetic acid preparation of the present invention has an optimal composition for sterilizing cereal seeds, controls seed infectious diseases such as fungal or bacterial diseases of cereal seeds, and is effective as a disease control method in which no phytotoxicity is observed in plants.

Modes for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments and can be implemented in various forms within the scope of the gist.

[0018] The peracetic acid preparation of the present invention can be prepared by mixing hydrogen peroxide and acetic acid. The concentrations and amounts of hydrogen peroxide and acetic acid to be used may be appropriately selected according to the concentration of peracetic acid to be obtained, based on the known equilibrium constant of peracetic acid. When hydrogen peroxide and acetic acid are mixed, stirred, and left standing at room temperature for several days, peracetic acid is generated by the chemical equilibrium reaction between the two, and a peracetic acid preparation is prepared.

[0019] The peracetic acid preparation of the present invention is used as it is or after being diluted so that the peracetic acid concentration becomes appropriate. Specifically, it can be obtained by diluting so as to contain 0.01% to 16% by mass of peracetic acid as an active ingredient. In addition, the peracetic acid preparation in the present invention can be safely used even at the actual site of use by being diluted and used.

[0020] In the peracetic acid formulation of the present invention, the concentrations of peracetic acid, acetic acid, and hydrogen peroxide may be adjusted using known methods. For example, the concentration of hydrogen peroxide may be reduced using additives such as catalase.

[0021] The bactericidal effect of the peracetic acid preparation of the present invention depends on the concentration of peracetic acid, the treatment time, the temperature, and the type of pathogenic bacteria or fungi being targeted. Therefore, it is necessary to set the appropriate concentration, treatment time, and treatment temperature taking these factors into consideration. This is due to the bactericidal mechanism of peracetic acid contained in the peracetic acid preparation. Peracetic acid, which has strong biopenetration and oxidizing power, irreversibly alters or inactivates elements essential for life-sustaining activities such as the membrane, enzymes, and DNA of pathogenic bacteria through oxidation, resulting in high bactericidal efficiency and a low likelihood of drug-resistant bacteria developing.

[0022] When using the peracetic acid preparation of the present invention after dilution, it is preferable to use a peracetic acid preparation with a peracetic acid concentration of 0.01% to 16% by mass, diluted 100 to 1000 times. The peracetic acid concentration in this case is preferably 100 ppm to 10000 ppm, and more preferably 100 to 2000 ppm.

[0023] When the peracetic acid preparation of the present invention is used in a sterilization method for grain seeds after dilution, it is preferable to use it as a pre-soaking treatment or a treatment during germination. The temperature for pre-soaking treatment is preferably 10 to 15°C. The duration of pre-soaking treatment is preferably 60 minutes to 48 hours, and more preferably 60 minutes to 24 hours.

[0024] When the peracetic acid preparation of the present invention is used during seed germination treatment, it is preferable to use warm water at approximately 30°C to 32°C. The duration of the seed germination treatment is preferably 60 minutes to 24 hours.

[0025] The present invention is highly effective against bacterial diseases and fungal diseases affecting grain seeds. Examples of bacterial diseases include bacterial blight, brown stripe disease, and bacterial seedling blight, with the present invention being more effective against bacterial blight. Examples of fungal diseases include bakanae disease, rice blast disease, and sesame leaf spot disease, with the present invention being more effective against bakanae disease or rice blast disease.

[0026] In the sterilization treatment method using the peracetic acid preparation of the present invention, seeds may be immersed directly in the peracetic acid preparation, or they may be placed in a cloth bag or net before treatment. In particular, when treating at a high concentration for a short time, it is necessary to quickly remove the seeds from the peracetic acid solution, and in such cases, considering the ability to drain the liquid, it is preferable to treat the seeds in a coarse mesh such as a net.

[0027] When sterilization treatment is performed with the peracetic acid formulation of the present invention, particularly with rice seeds, subsequent soaking and germination treatments can be carried out to ensure healthy germination and seedling growth. The sterilization effect of peracetic acid is evaluated using the control value. The control value is an index that represents the degree of control effect of the treated area against disease damage caused by bacteria and filamentous fungi in the untreated area, and generally, a higher control value indicates a greater control effect. Generally, The control value is calculated using the formula: (100 - (severity of disease in treated area / severity of disease in untreated area) × 100). A higher control value indicates a greater control effect. [Examples]

[0028] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0029] [Example 1]

[0030] [Formulation Examples 1 and 2, Formulation Comparative Examples 1 and 2] The concentrations of peracetic acid, acetic acid, and hydrogen peroxide were prepared to match the compositions listed in Table 1, and formulation Example 1 (Peracetic Acid B) and Formulation Example 2 (MO-1, Oxyper 100 (product name, manufactured by Hodogaya Chemical Co., Ltd.)) were prepared. For comparison, Formulation Comparative Example 1 (Peracetic Acid A) and a commercially available rice seed disinfectant (product name: Techlead C Flowable, ingredients: Ipconazole, cupric hydroxide) were also prepared.

[0031] [Table 1]

[0032] [Example 1, Example 2, Comparative Example 1, and Comparative Example 2] <Rice blight bacterial disease control trial> [Pre-treatment before soaking] Each peracetic acid preparation in Table 1 was diluted with water to prepare an aqueous solution with a concentration of 100 ppm. 25 mL of this aqueous solution was placed in a 100 mL beaker, and 12 g of rice grains contaminated with bacterial blight were immersed in it to examine the control effect. Immersion (pre-treatment before soaking) was carried out at 15°C for 24 hours. After soaking (pre-treatment), the rice seeds were soaked (for 3 days at 15°C) and germinated (at 32°C) for 24 hours. The germinated seeds were sown in a plastic case 1 / 12 the size of a seedling tray, filled with growing medium, kept at 32°C for 2 days, and then managed in a greenhouse. Fourteen days after sowing, the diseased seedling rate and disease severity were calculated using the following formula, and the control efficacy was calculated. Disease incidence index 3: Dead seedlings 2: Severe seedlings (wilted seedlings) 1: Mildly affected seedlings (yellowish-white seedlings, malformed seedlings) 0: Healthy Disease severity = {Σ(number of seedlings by disease severity) × (disease severity index) ÷ (number of seedlings surveyed × 3)} × 100 Pharmacovigilance is assessed by measuring the number of germinated seeds, with the number of germinated seeds in the untreated group set at 100. The germination inhibition rate (%) was calculated using the following formula. Germination inhibition rate (%) = (1 - (Number of germinated seeds in the treated area / Number of germinated seeds in the untreated area)) × 100 (%) For comparison, "Peracetic Acid A" (acetic acid / peracetic acid = 4.6 (mass ratio)) was used as Comparative Formulation 1, and a commercially available rice seed disinfectant (product name: Techlead C Flowable, ingredients: ipconazole, cupric hydroxide) was used as Comparative Formulation 2. The effectiveness was evaluated by control value, and phytotoxicity was evaluated by germination inhibition rate (%), according to the criteria in Table 2. The test results are shown in Table 3.

[0033] [Table 2]

[0034] [Table 3]

[0035] Table 3 shows that the peracetic acid formulation of the present invention caused fewer adverse drug reactions than the comparative examples.

[0036] [Examples 3, 4, 3, and 2] <Rice blight bacterial disease control trial> [Treatment during germination] Similar to Examples 1 and 2, peracetic acid, acetic acid, and hydrogen peroxide were prepared to the concentrations shown in Table 1, and formulation Example 1 (peracetic acid B) and Formulation Example 2 (MO-1, Oxyper 100 (product name, manufactured by Hodogaya Chemical Co., Ltd.)) were prepared. For comparison, Formulation Comparative Example 1 (peracetic acid A) and a commercially available rice seed disinfectant (product name: Techlead C Flowable, ingredients: ipconazole, cupric hydroxide) were also prepared.

[0037] Aqueous solutions of each peracetic acid preparation were prepared at three concentrations (250, 333, and 500 ppm). 45 mL of each aqueous solution was placed in a 100 mL beaker, and 12 g of rice seeds contaminated with bacterial blight were immersed in it (treatment during germination) to examine the control effect. The rice seeds used were soaked at 15°C. Immersion (treatment during germination) was carried out at 32°C for 24 hours. The germinated rice seeds were sown in a plastic case 1 / 12 the size of a seedling tray, filled with growing medium, kept at 32°C for two days, and then managed in a greenhouse. Fourteen days after sowing, the diseased seedling rate was calculated, and the disease severity was determined according to the formula below, as in Examples 1 and 2, and the control value was calculated. Disease incidence index 3: Dead seedlings 2: Severe seedlings (wilted seedlings) 1: Mildly affected seedlings (yellowish-white seedlings, malformed seedlings) 0: Healthy Disease severity = {Σ(number of seedlings by disease severity) × (disease severity index) ÷ (number of seedlings surveyed × 3)} × 100 Regarding phytotoxicity, the number of germinated seeds was measured, and the germination inhibition rate (%) was calculated using the following formula, with the number of germinated seeds in the untreated group set to 100. Germination inhibition rate (%) = (1 - (Number of germinated seeds in the treated area / Number of germinated seeds in the untreated area)) × 100 (%) For comparison, "Peracetic Acid A" (acetic acid / peracetic acid = 4.6 (mass ratio)) was used as Comparative Formulation 1, and a commercially available rice seed disinfectant (product name: Techlead C Flowable, ingredients: ipconazole, cupric hydroxide) was used as Comparative Formulation 2. The effectiveness was evaluated by control value, and phytotoxicity was evaluated by germination inhibition rate (%), according to the criteria in Table 2. The test results are shown in Table 4.

[0038] [Table 4]

[0039] Table 4 shows that the peracetic acid formulation of the present invention did not cause phytotoxicity at the above treatment concentrations and exhibited a higher control effect than the comparative example. [Industrial applicability]

[0040] The peracetic acid preparation of the present invention has an optimal composition of three components (peracetic acid, acetic acid, and hydrogen peroxide) from the viewpoint of bactericidal activity and phytotoxicity to plants such as grains. The method of sterilizing grain seeds using the peracetic acid preparation of the present invention is effective as a disease control method that prevents seed-infecting diseases such as filamentous fungal diseases or bacterial diseases in grain seeds without causing phytotoxicity to plants such as grains.

Claims

1. A peracetic acid preparation containing 0.01% to 16% by mass of peracetic acid as an active ingredient, The mass ratio of acetic acid to peracetic acid is acetic acid / peracetic acid = 1.0 to 1.1, and The mass ratio of hydrogen peroxide to peracetic acid is hydrogen peroxide / peracetic acid = 0.6 to 3.

1. A peracetic acid preparation for sterilizing grain seeds.

2. A method for sterilizing grain seeds by diluting the peracetic acid preparation described in claim 1 100 to 1000 times and using it as a pre-treatment for soaking.

3. A method for sterilizing grain seeds by diluting the peracetic acid preparation described in claim 1 100 to 1000 times and using it as a treatment during germination.

4. A peracetic acid preparation containing 0.01% to 16% by mass of peracetic acid as an active ingredient, The mass ratio of acetic acid to peracetic acid is acetic acid / peracetic acid = 1.0 to 3.1, and The mass ratio of hydrogen peroxide to peracetic acid is hydrogen peroxide / peracetic acid = 0.6 to 3.

1. A method for sterilizing grain seeds by diluting a peracetic acid preparation for grain seed sterilization treatment 100 to 1000 times and performing a pre-treatment soaking for 60 minutes or more.

5. A method for sterilizing grain seeds according to any one of Claims 2 to 4, characterized by immersion treatment, spraying treatment, or soil treatment using a peracetic acid preparation.

6. A method for controlling bacterial or fungal diseases of grain seeds, using the grain seed sterilization treatment method described in any one of claims 2 to 5.

7. The method for controlling bacterial diseases of grain seeds according to claim 6, wherein the bacterial disease is bacterial blight, brown stripe disease, or bacterial seedling blight.

8. The method for controlling fungal diseases of grain seeds according to claim 6, wherein the aforementioned fungal disease is bakanae disease, rice blast disease, or sesame leaf blight.

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