Method for controlling post-harvest disease

Abstract

Provided are a post-harvest disease control agent and a post-harvest disease control method that are effective in controlling a variety of post-harvest diseases and have reduced drug residues in foods. This post-harvest disease control agent contains water, and polymer particles suspended in the water, the polymer particles containing an amino acid compound and a cyanoacrylate polymer, and having a hydrodynamic diameter of less than 1000 nm. This post-harvest disease control method includes bringing harvested vegetables or fruits into contact with the post-harvest disease control agent.

Description

Post-harvest disease control method

[0001] The present invention relates to a control agent for post-harvest diseases and a method for controlling post-harvest diseases. More specifically, the present invention relates to a control agent for post-harvest diseases and a method for controlling post-harvest diseases that are effective in controlling various post-harvest diseases and have little drug residue in foods. This application claims priority to Japanese Patent Application No. 2024-176772 filed on October 8, 2024, and incorporates its content herein by reference.

[0002] As drug active ingredients for preventing spoilage of harvested agricultural products, especially fruits, basic salts such as sodium bicarbonate, mustard oil components, hinokitiol, etc. are known. However, their scope of application is limited to specific post-harvest diseases such as citrus green mold and blue mold.

[0003] By the way, Patent Document 1 discloses an antibacterial agent for plant pathogenic bacteria containing at least one selected from the group consisting of amino acids and their derivatives, and their oligomers and polymers, substantially not containing an antibacterial active ingredient against plant pathogenic bacteria, and having cyanoacrylate polymer particles with an average particle size of less than 1000 nm as an active ingredient. The antibacterial agent for plant pathogenic bacteria in Patent Document 1 is described as being able to be used not only for application to plants during cultivation but also for sterilizing and washing agricultural machinery and household gardening tools contaminated or likely to be contaminated with plant pathogenic bacteria.

[0004] Patent Document 2 discloses an antibacterial agent against fungi containing at least one selected from the group consisting of amino acids, amino acid derivatives, their oligomers and polymers, sugars, and polysorbate, not containing an antibacterial active ingredient against fungi, and having cyanoacrylate polymer particles with an average particle size of less than 1000 nm as an active ingredient.

[0005] Patent Document 3 discloses an antimicrobial particle aqueous dispersion characterized by containing particles that encapsulate an iodopropargyl compound and whose shell is composed of cyanoacrylate. Patent Document 4 discloses nanopolymer particles exhibiting anti-algal and antimicrobial activity, characterized by being composed of a polymer containing ethyl cyanoacrylate units.

[0006] Patent Document 5 discloses nanoparticles that can be used in agriculture, aquaculture, antimicrobial applications, etc., comprising a poly(alkylcyanoacrylate) homopolymer or copolymer, at least one activator, and an anion inhibitor and a radical inhibitor. Patent Document 6 discloses amino acid-conjugated cyanoacrylate polymer particles having an average particle size of less than 1000 nm.

[0007] WO 2013 / 108871 A Japanese Patent Publication No. 2015-157778 Japanese Patent Publication No. 2021-116264 Japanese Patent Publication No. 2023-83718 Japanese Patent Publication No. 2021-534209 WO 2010 / 101178 A1

[0008] Seo et al., "Common amino acids suppress plant diseases!? Plant power-up through amino acids," Kagaku to Seibutsu 56(6): 386-387 (2018)

[0009] The objective of the present invention is to provide a control agent and method for controlling post-harvest diseases that are effective in controlling various post-harvest diseases and leave little residue in food.

[0010] As a result of diligent research to solve the above problems, we have completed the present invention, which encompasses the following forms.

[0011] [1] A pest control agent for post-harvest diseases, comprising water and polymer particles suspended in the water, wherein the polymer particles contain an amino acid compound and a cyanoacrylate polymer and have a hydrodynamic diameter of less than 1000 nm. [2] The pest control agent according to [1], further comprising sugars and / or a surfactant.

[0012] [3] The pest control agent according to [1] or [2], wherein the amino acid compound is at least one selected from the group consisting of alanine, isoleucine, leucine, methionine, valine, phenylalanine, tryptophan, tyrosine, asparagine, cysteine, cystine, glutamine, serine, threonine, aspartic acid, glutamic acid, arginine, histidine, lysine, glycine, and proline.

[0013] [4] A pest control agent described in any one of [1] to [3], wherein the temperature is between 40 and 60°C.

[0014] [5] A method for controlling post-harvest diseases, comprising contacting harvested vegetables or fruits with any one of the control agents described in [1] to [4]. [6] A method for controlling post-harvest diseases, comprising contacting harvested vegetables or fruits with any one of the control agents described in [1] to [3] at a temperature of 40 to 60°C, and then contacting them with water; contacting harvested vegetables or fruits with any one of the control agents described in [1] to [3], and then contacting them with water at a temperature of 40 to 60°C; or contacting harvested vegetables or fruits with water at a temperature of 40 to 60°C, and then contacting them with an aqueous solution containing any one of the control agents described in [1] to [3].

[0015] [7] The control method described in [5] or [6], wherein the post-harvest disease is a plant disease caused by Gram-negative plant pathogenic bacteria or plant pathogenic filamentous fungi.

[0016] [8] The control method according to [5] or [6], wherein the post-harvest disease is a plant disease caused by fungi of the genus Penicillium, Geotrichum, Rhizopus, Botrytis, Colletotricum, Alternaria, or Monilinia. [9] The method according to any one of [5] to [8], wherein the vegetable or fruit belongs to the Rutaceae, Rosaceae, Actinidiaceae, Vitaceae, Lythraceae, Anacardiaceae, Cactaceae, Papayaceae, Lauraceae, Bromeliaceae, Ebenaceae, or Solanaceae.

[0017] The post-harvest disease control agent and method of the present invention are effective in controlling various types of post-harvest diseases. The natural amino acids and biomodified amino acids used in the post-harvest disease control agent of the present invention are harmless to the human body, and the cyanoacrylate polymer used in the post-harvest disease control agent of the present invention has low toxicity, to the point that it is used for skin damage repair. The cyanoacrylate polymer is said to be biodegradable and does not accumulate in the human body.

[0018] The present invention provides a control agent for post-harvest diseases, comprising water and polymer particles suspended in the water.

[0019] The polymer particles used in this invention contain an amino acid compound and a cyanoacrylate polymer.

[0020] Examples of amino acid compounds in this invention include protein-constituting amino acids (natural amino acids), non-protein-constituting amino acids (unnatural amino acids), and biomodified amino acids (amino acid derivatives). The concept of amino acid compounds in this invention encompasses optical isomers and geometric isomers. Amino acid compounds in this invention also include peptides composed of natural amino acids, peptides composed of unnatural amino acids, and peptides composed of natural and unnatural amino acids. A peptide is a compound in which two or more amino acids are linked by an amide bond. The number of amino acid units in a peptide is usually between 2 and 100. In this application, peptides with 2 to 10 amino acid units are called oligopeptides, and peptides with 11 to 100 amino acid units are called polypeptides.

[0021] Examples of natural amino acids include alanine, arginine, asparagine, aspartic acid, isoleucine, glutamic acid, glutamine, glycine, cysteine, cystine, threonine, serine, tyrosine, tryptophan, valine, histidine, phenylalanine, proline, methionine, lysine, and leucine.

[0022] Non-natural amino acids include those other than the natural amino acids mentioned above, which contain an amino group and a carboxyl group, and include β-amino acids, γ-amino acids, δ-amino acids, creatinine, ornithine, thyroxine, desmosine, hydroxyproline, hydroxylysine, phosphoserine, theanine, kainic acid, tricolomic acid, sarcosine, and the like.

[0023] Amino acid compounds can be incorporated into the polymer particles used in this invention either individually or in combination of two or more.

[0024] The cyanoacrylate polymer in this invention is defined as follows: It is obtained by polymerizing a cyanoacrylate monomer represented by the formula (wherein R represents a substituted or unsubstituted alkyl group, etc.).

[0025] Examples of the above-mentioned "alkyl group" include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, i-butyl group, t-butyl group, n-pentyl group, n-hexyl group, nonyl group, isononyl group, decyl group, dodecyl group, and the like. Preferably, it is an alkyl group having 1 to 8 carbon atoms.

[0026] The term "substituted" in "substituted or unsubstituted" is not particularly limited as long as it is chemically acceptable and has the effect of the present invention, and examples include C1-6 alkyl groups, hydroxyl groups, C1-6 alkoxy groups, halogeno groups, cyano groups, oxo groups, and the like.

[0027] The cyanoacrylate monomers used in this invention include methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, n-propyl 2-cyanoacrylate, isopropyl 2-cyanoacrylate, propagyl 2-cyanoacrylate, allyl 2-cyanoacrylate, n-butyl 2-cyanoacrylate, isobutyl 2-cyanoacrylate, s-butyl 2-cyanoacrylate, t-butyl 2-cyanoacrylate, chloroethyl 2-cyanoacrylate, cyclohexyl 2-cyanoacrylate, phenyl 2-cyanoacrylate, n-pentyl 2-cyanoacrylate, n-hexyl 2-cyanoacrylate, isopentyl 2-cyanoacrylate, isohexyl 2-cyanoacrylate, tetrahydrofurfuryl 2-cyanoacrylate, and heptyl 2-cyanoacrylate. Examples include acrylates, 2-ethylhexyl 2-cyanoacrylate, n-octyl 2-cyanoacrylate, n-nonyl 2-cyanoacrylate, oxononyl 2-cyanoacrylate, n-decyl 2-cyanoacrylate, n-dodecyl 2-cyanoacrylate, 2-ethoxyethyl 2-cyanoacrylate, 3-methoxybutyl 2-cyanoacrylate, 2-ethoxy-2-ethoxyethyl 2-cyanoacrylate, butoxy-ethoxy-ethyl 2-cyanoacrylate, methoxyisopropyl cyanoacrylate, methoxypropyl cyanoacrylate, methoxybutyl cyanoacrylate, methoxypentyl cyanoacrylate, 2,2,2-trifluoroethyl 2-cyanoacrylate, and hexafluoroisopropyl 2-cyanoacrylate. Of these, n-butyl 2-cyanoacrylate, isobutyl 2-cyanoacrylate, and n-octyl 2-cyanoacrylate are preferred. The cyanoacrylate monomers can be polymerized individually or in combination of two or more.

[0028] The polymer particles used in the present invention contain, preferably, 1 to 60 parts by weight, more preferably 10 to 40 parts by weight, of an amino acid compound per 100 parts by weight of a cyanoacrylate polymer.

[0029] The polymer particles used in the present invention can be obtained, for example, by a method that includes polymerizing cyanoacrylate monomers in the presence of an amino acid compound, or more specifically, by a method that includes adding cyanoacrylate monomers to a liquid containing an amino acid compound, stirring to obtain a dispersion of cyanoacrylate monomers, and then proceeding with an anionic polymerization reaction in that state.

[0030] The medium used in the liquid containing the amino acid compound is not particularly limited as long as it can dissolve or suspend the amino acid compound. Examples include protic polar solvents such as water and alcohol, preferably water or methanol, more preferably water. Note that water or methanol initiates the polymerization reaction of cyanoacrylate monomers, as described later.

[0031] Cyanoacrylate monomers may be subjected to polymerization reactions as they are, or they may be subjected to polymerization reactions after being dissolved or suspended in a medium. Examples of media for dissolving or suspending cyanoacrylate monomers include aprotic polar solvents such as N-methylpyrrolidone, dichloromethane, acetonitrile, N,N-dimethylformamide, hexamethylphosphate triamide, dimethyl sulfoxide, tetrahydrofuran, ethyl acetate, acetone, methyl ethyl ketone, and propylene carbonate; protic polar solvents such as nitromethane; and nonpolar solvents such as hexane, benzene, toluene, 1,4-dioxane, chloroform, and diethyl ether.

[0032] Anionic polymerization is carried out to polymerize cyanoacrylate monomers. Anionic polymerization is initiated by anions. Examples of anions include hydroxide ions and alkoxide ions. Examples of substances that supply anions (initiators) include water and alcohols, and examples of substances that adjust the amount of anions in the polymerization reaction system include amines, bases such as metal hydroxides, and acids such as hydrochloric acid, nitric acid, sulfuric acid, and organic acids. The rate of the polymerization reaction can be changed by adjusting the amount of anions.

[0033] In the anionic polymerization reaction of cyanoacrylate monomers, saccharides (monosaccharides and disaccharides, oligosaccharides and other polysaccharides) or surfactants can be used as stabilizers. The stabilizer may alter the particle size and the amount of amino acid compounds that can be contained in the particles. Examples of polysaccharides include dextran and cyclodextrin.

[0034] The temperature in the anionic polymerization reaction of cyanoacrylate monomer is not particularly limited, but is preferably 0 to 100°C, more preferably 1 to 50°C. The amount of cyanoacrylate monomer relative to the liquid containing the amino acid compound is preferably 0.1% to 10% by weight, more preferably 0.5% to 5% by weight. The time from the start to the end of the anionic polymerization reaction of cyanoacrylate monomer is preferably 0.5 to 6 hours, more preferably 1 to 3 hours.

[0035] Since the polymer particles in this invention are suspended in water when the polymerization reaction of cyanoacrylate monomer using water as the medium is completed, they may be used as is or after neutralization as a post-harvest disease control agent of this invention.

[0036] Furthermore, after the polymerization reaction of the cyanoacrylate monomer is completed, the polymer particles may be removed by neutralization, filtration, washing, etc., as needed, and suspended in fresh water to obtain the post-harvest disease control agent of the present invention. Alternatively, the removed polymer particles may be stored or transported in a dry state, and the dried polymer particles may be suspended in water at the site where the disease control treatment is performed to obtain the post-harvest disease control agent of the present invention.

[0037] The post-harvest disease control agent of the present invention is preferably used at a temperature of 30 to 70°C, more preferably 35 to 65°C, even more preferably 40 to 60°C, and even more preferably 50 to 60°C. Higher temperatures increase the effectiveness against post-harvest diseases, but tend to cause thermal denaturation of plant cells. When using a high-temperature control agent, it is preferable to shorten the time it is in contact with vegetables or fruits after harvest.

[0038] The post-harvest disease control agent of the present invention has a pH of preferably 4 to 10, more preferably 6 to 8, and even more preferably 6 to 6.5. Each microorganism has a pH suitable for its growth. It is said that the growth of microorganisms is suppressed when the pH deviates from the optimal value. The optimal pH for fungal growth is said to be 4 to 6. On the other hand, lactic acid bacteria are said to have an effect of suppressing plant diseases. Lactobacillus and other lactobacillus species have an acidic growth limit of 4.0, an alkaline growth limit of 8, and an optimal growth pH of 6 to 7. Lactic acid bacteria, which are useful in suppressing plant diseases, grow easily in weakly acidic conditions such as 6 to 6.5, while fungi do not seem to grow easily. Furthermore, most fruits are acidic. For example, apples have a pH of 2.9–3.3, pears 3.7–4.2, grapes 3.0–3.3, tomatoes 3.8–4.6, oranges 3.0–3.5, and lemons 2.4–2.8.

[0039] The pH of the post-harvest disease control agent of the present invention is preferably adjusted using food additive pH adjusters such as citric acid, sodium citrate, acetic acid, acetate, and phosphate. Acetic acid and phosphoric acid may improve the effectiveness of post-harvest disease control.

[0040] The size of polymer particles suspended in water is less than 1000 nm, preferably less than 500 nm, in terms of hydrodynamic diameter. There is no particular lower limit to the size of polymer particles suspended in water, but it is preferably 1 nm, more preferably 5 nm. Smaller polymer particles tend to adhere better to vegetables or fruits after harvest, and smaller polymer particles tend to be easier to remove by washing after pest control treatment. Hydrodynamic diameter refers to the particle diameter of smooth, spherical particles that diffuse at the same speed as the polymer particles. The hydrodynamic diameter is obtained by measuring the scattering intensity of polymer particles dispersed in a liquid using dynamic light scattering, determining the autocorrelation function based on the fluctuations of the measured scattering intensity, and performing cumulant analysis (ISO 22412:2017).

[0041] The amount of polymer particles contained in the post-harvest disease control agent of the present invention is not particularly limited. For example, during storage and transportation, it is preferably 500 to 20,000 ppm, more preferably 1000 to 20,000 ppm, relative to water. When contacting post-harvest vegetables or fruits, it is preferably 1000 to 10,000 ppm, more preferably 1250 to 5000 ppm, relative to water. The adjustment of the amount of polymer particles contained in the post-harvest disease control agent is carried out, for example, by dilution with water, an aqueous solution, or the like.

[0042] The method for controlling post-harvest diseases includes contacting post-harvest vegetables or fruits with the control agent of the present invention. Preferred embodiments of the method for controlling post-harvest diseases of the present invention include contacting post-harvest vegetables or fruits with the control agent of the present invention at a temperature of 40 to 60°C; contacting post-harvest vegetables or fruits with the control agent of the present invention at a temperature of 40 to 60°C and then contacting them with water; contacting post-harvest vegetables or fruits with the control agent of the present invention and then contacting them with water at 40 to 60°C; or contacting post-harvest vegetables or fruits with water at 40 to 60°C and then contacting them with an aqueous solution containing the control agent of the present invention.

[0043] Examples of the method for contacting the post-harvest vegetables or fruits with the control agent or water of the present invention include dipping, spraying a liquid, or spraying.

[0044] When the temperature and time of contacting the control agent or water of the present invention are such that the harvested vegetables or fruits are not overcooked. It is preferable that the time of contacting the control agent of the present invention at a temperature exceeding 60°C is short so that the harvested vegetables or fruits are not overcooked, for example, preferably 0.01 minutes or more and 8 minutes or less, more preferably 0.05 minutes or more and 5 minutes or less, still more preferably 0.1 minutes or more and 2 minutes or less. The time of contacting the control agent of the present invention at a temperature of 40 to 60°C is, for example, preferably 0.5 minutes or more and 20 minutes or less, more preferably 1 minute or more and 15 minutes or less, still more preferably 2 minutes or more and 10 minutes or less. The time of contacting the control agent of the present invention at a temperature exceeding 0°C and less than 40°C is, for example, preferably 1 minute or more and 40 minutes or less, more preferably 1.5 minutes or more and 30 minutes or less, still more preferably 2 minutes or more and 20 minutes or less.

[0045] The time of contacting water at a temperature exceeding 60°C is short so that the harvested vegetables or fruits are not overcooked, for example, preferably 0.01 minutes or more and 8 minutes or less, more preferably 0.05 minutes or more and 5 minutes or less, still more preferably 0.1 minutes or more and 2 minutes or less. The time of contacting water at a temperature of 40 to 60°C is, for example, preferably 0.5 minutes or more and 20 minutes or less, more preferably 1 minute or more and 15 minutes or less, still more preferably 2 minutes or more and 10 minutes or less. The time of contacting water at a temperature exceeding 0°C and less than 40°C is, for example, preferably 1 minute or more and 40 minutes or less, more preferably 1.5 minutes or more and 30 minutes or less, still more preferably 2 minutes or more and 20 minutes or less.

[0046] The control agent for post-harvest diseases and the method for controlling post-harvest diseases of the present invention are suitable for plant diseases caused by Gram-negative plant pathogenic bacteria or plant pathogenic filamentous fungi, and are more suitable for plant diseases caused by fungi of the genus Penicillium, Geotrichum, Rhizopus, Botrytis, Colletotrichum, Alternaria, or Monilinia.

[0047] The post-harvest vegetables or fruits targeted by the post-harvest disease control agent and post-harvest disease control method of the present invention are preferably plants belonging to the Rutaceae family such as mandarins and grapefruits, Rosaceae family such as apples, cherries, pears, loquats, peaches, and berries, Actinidiaceae family such as kiwifruit, Vitaceae family such as grapes, Lythraceae family such as pomegranates, Anacardiaceae family such as mangoes, Cactaceae family such as dragon fruit, Papaya family such as papayas, Lauraceae family such as avocados, Bromeliaceae family such as pineapples, Ebenaceae family such as persimmons, or Solanaceae family such as tomatoes.

[0048] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0049] [Test Example 1] A pincushion (1 x 1 cm) made by bundling five sewing needles together. ２ We prepared the following: We stuck the spikes into each of the 10 harvested Satsuma mandarin oranges (Okitsu Wase variety), making 6mm deep cuts on the surface of the peel of each orange.

[0050] (Inoculation with disease-causing fungus) Approximately 0.2 x 10 spores of citrus green mold (Penicillium digitatum) ４ A solution of pathogenic fungi was obtained by adding them to deionized water to a concentration of 100 particles / mL. The pathogenic fungal solution was placed in a container and sprayed over the entire mandarin orange fruit using a manual pressurized spray device. Immediately after spraying, 10 mandarin oranges were placed in each new plastic bag, and the openings of each bag were tied. These were then placed in a cardboard box and left to stand overnight at 20°C in a dark place.

[0051] (Control Treatment) The day after inoculation with the pathogen, n-butylcyanoacrylate polymer particles containing 29% aspartic acid with a hydrodynamic diameter of 140 nm (AspNBCA particles) were added to a 0.01% polyethylene glycol sorbitan monolaurate aqueous solution to obtain a control agent. The control agent was placed in a constant temperature water bath and adjusted to the specified temperature. The mandarin oranges were removed from the plastic bags. The mandarin oranges were immersed in the control agent in the constant temperature water bath for 2 minutes.

[0052] (Re-inoculation with disease-causing fungi) The mandarin fruits that had been in contact with the control agent were air-dried. Then, the disease-causing fungus solution obtained by the same method as above was placed in a container and sprayed over the entire mandarin fruit using a manual pressurized spray device. Immediately after spraying, 10 mandarin fruits were placed in each new plastic bag, and the opening of each bag was tied. These were then placed in a cardboard box and left to stand in a dark place at 20°C.

[0053] (Measurement of the number of diseased fruits) Mandarin orange fruits were observed on the 3rd, 4th, and 5th day after reinoculation with the disease-causing fungus to check for the presence or absence of disease.

[0054] Multiple procedures were carried out simultaneously: inoculation with the disease pathogen, control treatment, reinoculation with the disease pathogen, and measurement of the number of diseased fruits. The results are shown in Table 1. Control value (%) = 100 - (Disease incidence rate in controlled plots / Disease incidence rate in untreated plots) × 100 Disease incidence rate (%) = (Number of diseased fruits / Total number of fruits) × 100

[0055]

[0056] As shown in Table 1, applying the pest control agent of the present invention can suppress the growth of pathogenic fungi in vegetables or fruits after harvest.

[0057] [Test Example 2] Inoculation with pathogenic fungi, control treatment, and reinoculation with pathogenic fungi were performed using the same method as in Test Example 1, except that the timing was changed.

[0058] (Measurement of the number of diseased fruits) Mandarin orange fruits were observed on the 9th and 12th day after reinoculation with the disease-causing fungus to check for the presence or absence of disease.

[0059] Multiple procedures were carried out simultaneously: inoculation with the disease pathogen, control treatment, reinoculation with the disease pathogen, and measurement of the number of diseased fruits. The results are shown in Table 2. Control value (%) = 100 - (Disease incidence rate in controlled plots / Disease incidence rate in untreated plots) × 100 Disease incidence rate (%) = (Number of diseased fruits / Total number of fruits) × 100

[0060]

[0061] [Test Example 3] Except for changing the timing, the same method as in Test Example 2 was used for inoculation with the pathogen, control treatment, and reinoculation with the pathogen, all performed simultaneously on multiple samples.

[0062] (Measurement of the number of diseased fruits) Mandarin orange fruits were observed 10 and 13 days after the reinoculation with the disease-causing fungus to check for the presence or absence of disease.

[0063] Multiple procedures were carried out simultaneously: inoculation with the disease pathogen, control treatment, reinoculation with the disease pathogen, and measurement of the number of diseased fruits. The results are shown in Table 3. Control value (%) = 100 - (Disease incidence rate in controlled plots / Disease incidence rate in untreated plots) × 100 Disease incidence rate (%) = (Number of diseased fruits / Total number of fruits) × 100

[0064]

[0065] [Test Example 4] Except for changing the timing, the same method as in Test Example 3 was used for inoculation with the pathogen, control treatment, and reinoculation with the pathogen, all performed simultaneously on multiple samples.

[0066] (Measurement of the number of diseased fruits) Mandarin orange fruits were observed on the 4th and 6th day after reinoculation with the disease-causing fungus to check for the presence or absence of disease.

[0067] Multiple procedures were carried out simultaneously: inoculation with the disease pathogen, control treatment, reinoculation with the disease pathogen, and measurement of the number of diseased fruits. The results are shown in Table 4. Control value (%) = 100 - (Disease incidence rate in controlled plots / Disease incidence rate in untreated plots) × 100 Disease incidence rate (%) = (Number of diseased fruits / Total number of fruits) × 100

[0068]

Claims

1. A post-harvest disease control agent comprising water and polymer particles suspended in the water, wherein the polymer particles contain an amino acid compound and a cyanoacrylate polymer and have a hydrodynamic diameter of less than 1000 nm.

2. The pest control agent according to claim 1, further comprising sugars and / or surfactants.

3. The pest control agent according to claim 1, wherein the amino acid is at least one selected from the group consisting of alanine, isoleucine, leucine, methionine, valine, phenylalanine, tryptophan, tyrosine, asparagine, cysteine, cystine, glutamine, serine, threonine, aspartic acid, glutamic acid, arginine, histidine, lysine, glycine, and proline.

4. The pest control agent according to claim 1, wherein the temperature is 40 to 60°C.

5. A method for controlling post-harvest diseases, comprising contacting harvested vegetables or fruits with the control agent described in claim 1.

6. A method for controlling post-harvest diseases, comprising: contacting harvested vegetables or fruits with the control agent described in claim 1 at a temperature of 40 to 60°C; contacting harvested vegetables or fruits with the control agent described in claim 1 at a temperature of 40 to 60°C and then contacting them with water; contacting harvested vegetables or fruits with the control agent described in claim 1 and then contacting them with water at a temperature of 40 to 60°C; or contacting harvested vegetables or fruits with water at a temperature of 40 to 60°C and then contacting them with an aqueous solution containing the control agent described in claim 1.

7. The method according to claim 5 or 6, wherein the post-harvest disease is a plant disease caused by Gram-negative plant pathogenic bacteria or plant pathogenic filamentous fungi.

8. The method according to claim 5 or 6, wherein the post-harvest disease is a plant disease caused by a fungus of the genus Penicillium, Geotrichum, Rhizopus, Botrytis, Colletotricum, Alternaria, or Monilinia.

9. The method according to claim 5 or 6, wherein the vegetable or fruit belongs to the Rutaceae, Rosaceae, Actinidiaceae, Vitaceae, Lythraceae, Anacardiaceae, Cactaceae, Papayaceae, Lauraceae, Bromeliaceae, Ebenaceae, or Solanaceae families.

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