Plant disease control composition

Abstract

Provided are: a novel plant disease control method that can be implemented in addition to or as an alternative to conventional, chemical pesticide disease control methods for plants which have the purpose of disinfection and the like of seeds and soil; and a plant disease composition that can be used in said method.　Plants are grown with the application of a plant disease control composition for preventing or reducing plant diseases due to microorganisms, said composition including allantoin as an active ingredient.

Description

Composition for controlling plant diseases

[0001] This specification discloses compositions for controlling plant diseases and methods for controlling plant diseases using the same.

[0002] The causes of plant diseases are diverse, ranging from infectious pathogens such as fungi, bacteria / actinomycetes, phytoplasmas, plant viruses, nematodes, mites and other small animals, and terrestrial algae, to non-infectious pathogens such as nutrient deficiencies / excesses, water overload, and phytotoxicity. There are more than 10,000 types of plant diseases (Non-Patent Literature 1).

[0003] As a method of controlling diseases caused by pathogenic microorganisms, chemical control methods, such as sterilization and disinfection of seeds and soil using chemical pesticides, have been widely adopted. The reason for the widespread use of chemical pesticides is that they are highly effective and can be applied with less labor compared to other methods. However, there are concerns that chemical pesticides affect ecosystems, especially agricultural land, and the environment, including soil, water, and air. Against this backdrop, Integrated Pest Management (IPM) is attracting attention as a pest and disease control method that maintains crop productivity while also considering the environment. IPM is a comprehensive technology that combines control methods other than chemical pesticides, such as crop types, resistant varieties, physical methods using heat disinfection and machinery, and the use of natural enemies and pheromones (Non-Patent Literature 2). In this way, there have been widespread attempts to reduce the amount of conventional chemical pesticides used as much as possible.

[0004] Allantoin (5-ureidohydantoin) is an intermediate product produced during the degradation of nucleic acid bases (purine bases). In plants, allantoin is produced from 5-hydroxyisouric acid by allantoin synthase (AS) and then broken down into allantoic acid by allantoinase (ALN). Non-patent document 3 discloses that in Arabidopsis thaliana, an aln-1 mutant strain, in which the ALN gene is disrupted to accumulate allantoin in the plant body, exhibits higher drought stress tolerance compared to the wild type.

[0005] Patent Document 1 discloses a heat stress tolerance enhancer for improving the heat stress tolerance of plants, which contains allantoin as an active ingredient.

[0006] International Publication No. 2017 / 130630

[0007] Toyozo Sato, Journal of the Japanese Society for Microbial Resources (2013), Vol. 29, No. 2, pp. 79-90. Ministry of Agriculture, Forestry and Fisheries, Agriculture, Forestry and Fisheries Research Council, Agricultural, Forestry and Fisheries Research and Development Report No. 12, "Integrated Management Technology for Plant Diseases and Pests - Pest and Disease Control Not Relying Solely on Chemical Pesticides -" (2005) URL https: / / www.affrc.maff.go.jp / docs / report / pdf / no12.pdf S. Watanabe, et al., Plant Cell Environ. (2014) Vol. 37, pp. 1022-1036

[0008] This specification discloses a novel method for controlling plant diseases that can be implemented in addition to, or as an alternative to, conventional methods for controlling plant diseases using chemical pesticides for the purpose of sterilizing and disinfecting seeds and soil, and a plant disease control composition that can be used therefor.

[0009] This specification discloses the following inventions: (1) A plant disease control composition comprising allantoin as an active ingredient for preventing or reducing plant diseases caused by microorganisms. (2) The composition according to (1), wherein the disease is caused by filamentous fungi or oomycetes. (3) The composition according to (2), wherein the disease is caused by filamentous fungi, and the filamentous fungi are of the genus Rhizoctonia. (4) The composition according to (2), wherein the disease is caused by oomycetes, and the oomycetes are of the genus Pythium. (5) The composition according to any one of (1) to (4), wherein the disease is a soil-borne disease. (6) The composition according to any one of (1) to (5), further comprising a biosurfactant. (7) The composition according to (6), wherein the biosurfactant is surfactant. (8) The composition according to any one of (1) to (7), used for coating plant seeds. (9) The composition according to any one of (1) to (8), further comprising glutathione. (10) The composition according to any one of (1) to (9), further comprising an amino acid. (11) The composition according to (10), wherein the amino acid is L-tryptophan. (12) The composition according to any one of (1) to (11), further comprising an agriculturally acceptable carrier. (13) Coated seeds with reduced risk of microbial disease, comprising a composition containing allantoin on the surface. (14) Coated seeds according to (13), comprising 2 g or more of allantoin per ton of the coated seeds. (15) Coated seeds according to (13) or (14), wherein the disease is a disease caused by filamentous fungi or oomycetes. (16) Coated seeds according to (15), wherein the disease is a disease caused by filamentous fungi, and the filamentous fungi are of the genus Rhizoctonia. (17) The coated seed according to (15), wherein the disease is caused by an oomycete, and the oomycete is of the genus Pythium. (18) The coated seed according to any one of (13) to (17), wherein the disease is a soil-borne disease. (19) The coated seed according to any one of (13) to (18), further comprising a biosurfactant. (20) The coated seed according to (19), wherein the biosurfactant is surfactant. (21) The coated seed according to any one of (13) to (20), further comprising glutathione. (22) The coated seed according to any one of (13) to (21), further comprising an amino acid.(23) The coated seed according to (22), wherein the amino acid is L-tryptophan. (24) A method for preventing or reducing microbial diseases of plants, comprising sowing a coated seed according to any one of (13) to (23), and growing the plant from the coated seed after sowing. (25) The method according to (24), further comprising using other plant disease control means. This specification encompasses the disclosures of Japanese Patent Application No. 2025-011058, which forms the basis of the priority of this application.

[0010] According to the invention disclosed herein, it is possible to control plant diseases in addition to, or as an alternative to, conventional methods of controlling plant diseases using chemical pesticides for the purpose of bacterial and disinfection of seeds and soil.

[0011] Figure 1 is a photograph showing the appearance of soybeans 11 days after sowing, grown from seeds treated with allantoin and allantoin + surfactin in soil containing rhizoctonia in Example 1. Figure 2 is a photograph showing the appearance of soybeans 11 days after sowing, grown from seeds treated with allantoin in soil containing Pythium in Example 2.

[0012] 1. Composition for Controlling Plant Diseases The first embodiment disclosed herein is a composition for controlling plant diseases. The composition of this embodiment is characterized by containing allantoin as an active ingredient and being used to prevent or reduce plant diseases caused by microorganisms.

[0013] Allantoin itself is not known to have any bactericidal or disinfectant effect against plant pathogens. As a result of diligent research, the inventors have found that applying allantoin to plants can suppress the development of plant diseases caused by at least some pathogenic microorganisms, and have completed the present invention. Since allantoin itself does not show any bactericidal effect against fungi and has not been found to be toxic to plants, insects, animals, etc., the risk of soil contamination and adverse effects on ecosystems when applied to plants is extremely low. Therefore, by using the composition of this embodiment in place of some or all of conventional chemical control agents, it is possible to reduce the amount of chemical control agents used while maintaining the control function, thereby reducing the risk of soil contamination and adverse effects on ecosystems.

[0014] <Plant Diseases> In this specification, "plant disease" refers to diseases caused by microorganisms. Microorganisms here refer to fungi, bacteria / actinomycetes, and phytoplasmas. Diseases caused by microorganisms are not particularly limited, but examples include damping-off, downy mildew, late blight, root rot, powdery mildew, and white mold. In this specification, microorganisms include all microorganisms known as plant pathogens. In this specification, the plant pathogens to be controlled are preferably filamentous fungi or oomycetes.

[0015] In this specification, "filamentous fungi" is a general term for eukaryotic microorganisms that produce filamentous hyphae and reproduce by spores. Filamentous fungi known as plant pathogens include zygomycetes such as Rhizopus, basidiomycetes such as Ceratobasidium, Exobasidium, and Psinia, and genera such as Alteranaria, Botridis, Circospora, Cladosporium, Coletotricum, Corinespora, Cylindrosporium, Didymera, Diplocarpon, Discula, Erysife, Fusarium, Heterosporium, Rebeirula, Mycocaetophora, and Mycosphing Examples of ascomycetes / imperfect fungi include genera such as Aerella, Mycobelosiera, Oidium, Passarola, Pestalothiopsis, Homopossis, Philosticta, Plectosoporium, Pleospora, Podosphaera, Pseudocircospora, Pseudocircosporella, Pseudoidium, Pyricularia, Rhizoctonia, Sclerotinia, Septoria, Sphaerotheca, Stemphylium, and Trichoderma.

[0016] In this specification, suitable filamentous fungi for control include those of the genus Rhizoctonia. Examples of Rhizoctonia species include Rhizoctonia solani, Rhizoctonia bataticola, Rhizoctonia carotae, Rhizoctonia crocorum, Rhizoctonia leguminicola, Rhizoctonia oryzae, Rhizoctonia rubi, and Rhizoctonia zeae. Rhizoctonia solani is a particularly suitable target for control.

[0017] In this specification, "oomycetes" refers to a group of prokaryotes known to be phylogenetically distinct from fungi, which reproduce sexually through archegonia and antheridia, producing oospores. Known oomycetes that are plant pathogens include genera such as Albugo, Bremia, Hyalperonospora, Peronospora, Phytophytra, Plasmopara, Pseudoperonospora, and Pythium.

[0018] In this specification, suitable oomycetes to control include those of the genus Pythium. Examples of the genus Pythium include Pythium aphanidermatum, Pythium myriotylum, Pythium scleroteichum, Pythium sulcatum, Pythium aristosporum, Pythium dissotocum, Pythium arrhenomanes, Pythium graminicola, Pythium vanterpooli, Pythium volutum, Pythium porphyrae, Pythium flevoense, Pythium insidiosum, Pythium debaryanum, Pythium iwayamai, Pythium paddicum, Pythium irregulare, Pythium mamillatum, Pythium paroecandrum, Pythium sylvaticum, Pythium spinosum, Pythium splenden, Pythium ultimum, Pythium uncinulatum, Pythium megalacanthum, Pythium Known species include Pythium undulatum and Pythium helicoides. Particularly suitable targets for control are Pythium aphanidermatum and Pythium ultimum.

[0019] Both the genera Rhizoctonia and Pythium are known to be pathogens of seedling blight. The composition of this embodiment is preferably an effective composition for reducing the risk of seedling blight.

[0020] In this specification, the diseases to be controlled are preferably soil-borne diseases. In this specification, "soil-borne diseases" refers to crop growth disorders caused by pathogens and nematodes lurking in the soil. These diseases are generally known to be more difficult to control than other diseases and can lead to significant economic damage.

[0021] <Allantoin> In this specification, "allantoin," also known as 5-ureidohydantoin, refers to a compound having a structure represented by the following formula (I) in its free form.

[0022]

[0023] Allantoin has one chiral carbon (indicated by * in the formula), and optical isomers exist of (R)-allantoin and (S)-allantoin. The allantoin used in one or more embodiments of the present invention may be (R)-allantoin, (S)-allantoin, or a mixture thereof. Allantoin can be produced, for example, by synthesis from glyoxylic acid and urea. Allantoin may also be derived from or obtained from plants or microorganisms.

[0024] Allantoin may encompass various forms, including its free form (not bound to other substances and not ionized), its salts and hydrates, and mixtures of two or more of these.

[0025] <Plants> In this specification, "plants" are not particularly limited, but are preferably crop plants. Examples of crop plants include corn (maize), wheat, barley, rye, oats, rice, soybeans, canola (rapeseed), cotton, sunflowers, sugar beets, potatoes, tobacco, broccoli, lettuce, cabbage, cauliflower, coconuts, tomatoes, cucumbers, eggplants, melons, pumpkins, okra, bell peppers, watermelons, carrots, radishes, onions, leeks, flowers, turf, and pasture grasses. In this specification, "seeds" may be the seeds of these plants.

[0026] <Biosurfactant> The composition of this embodiment may contain a biosurfactant. Examples of biosurfactants include at least one biosurfactant selected from peptide-type biosurfactants and sugar-type biosurfactants. The composition of this embodiment may contain one biosurfactant alone or two or more biosurfactants. When the composition of this embodiment contains a biosurfactant, it can promote the absorption of allantoin, the active ingredient, into plants, thereby enhancing the effect of allantoin.

[0027] Peptide-type biosurfactants are not particularly limited as long as they have a peptide structure and surfactant properties, but examples include lipopeptide biosurfactants. Lipopeptide biosurfactants are peptides that contain hydrophobic groups and hydrophilic moieties, have surfactant properties, and are produced by microorganisms. Examples of lipopeptide biosurfactants include surfactant, aruthlofactin, ituurine, phendisine, selawettin, lykesin, viscosine, and their salts.

[0028] As the peptide-type biosurfactant, at least one peptide-type biosurfactant selected from surfactant and its salts is preferred, and at least one peptide-type biosurfactant selected from surfactant and its salts is more preferred. Surfactin and surfactant salts can be represented by the following general formula (II). One type or two or more types of surfactant and surfactant salts may be used.

[0029] [In formula (II), X represents an amino acid residue selected from leucine, isoleucine, and valine, R represents an alkyl group having 9 to 18 carbon atoms, and M ＋ Each of them independently produces a hydrogen ion (H + ), represents alkali metal ions, ammonium ions, or pyridinium ions.

[0030] Note M ＋When it is a hydrogen ion, it means CO ２ ‐ (M ＋ ) represents a carboxy group (COOH group). When two M ＋ are hydrogen ions, it is surfactin, and when at least one of M ＋ is an alkali metal ion, an ammonium ion or a pyridinium ion, it means a salt of surfactin. The general formula of surfactin is shown in the following general formula (II').

[0031] [In formula (II'), X and R have the same meanings as in formula (II)]

[0032] X is a residue of an amino acid selected from leucine, isoleucine and valine, and it may be a residue of an L-form amino acid or a residue of a D-form amino acid, and a residue of an L-form amino acid is preferred.

[0033] R is an alkyl group having 9 to 18 carbon atoms, and is a linear or branched monovalent saturated hydrocarbon group having 9 or more and 18 or less carbon atoms. Examples of the alkyl group having 9 to 18 carbon atoms include an n-nonyl group, a 6-methyloctyl group, a 7-methyloctyl group, an n-decyl group, an 8-methylnonyl group, an n-undecyl group, a 9-methyldecyl group, an n-dodecyl group, a 10-methylundecyl group, an n-tridecyl group, an 11-methyldodecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, etc., and a 10-methylundecyl group is preferred.

[0034] M ＋ are each independently a hydrogen ion (H + ), an alkali metal ion, an ammonium ion or a pyridinium ion. The alkali metal ion is not particularly limited, and represents a lithium ion, a sodium ion, a potassium ion, etc. The ammonium ion is not particularly limited, and examples thereof include an ammonium ion represented by N(R １ ) ４ + . R １ each independently represents hydrogen or an organic group. As the ammonium ion, R１ One preferred embodiment is a quaternary ammonium ion in which all atoms are organic groups. Examples of organic groups include alkyl groups, aralkyl groups, and aryl groups. Specifically, examples of alkyl groups include C1-C10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and t-butyl; examples of aralkyl groups include C7-C12 aralkyl groups such as benzyl, methylbenzyl, and phenylethyl; and examples of aryl groups include C6-C15 aryl groups such as phenyl, toluyl, and xylyl. Examples of ammonium ions include tetramethylammonium ions and tetraethylammonium ions. The pyridinium ion is not particularly limited. In the pyridinium ion, the hydrogen atoms bonded to the carbon atoms constituting the pyridine ring may be substituted with organic groups. In addition, the pyridinium ion may include N atoms constituting the pyridine ring. ＋ The bond to it can be, for example, hydrogen or an organic group. The organic group that the pyridinium ion possesses is R. １ The organic groups mentioned in the explanation can be used as appropriate.

[0035] The two Ms present in general formula (II) ＋ These two Ms may be the same or different from each other. ＋ For example, some M ＋ These are hydrogen ions, and some M ＋ One preferred embodiment is that M is an alkali metal ion. The alkali metal ion is not particularly limited, but can be lithium ions, sodium ions, potassium ions, etc. Note that the two M present in general formula (II) ＋ However, if there are two or more ions, when we focus on one molecule (salt), there are two M ＋ These may be the same type of ion. ＋ When there are two types of ions, the ratio (molar ratio) of ion A to ion B is, for example, 1:10 to 10:1, preferably 1:5 to 5:1, and more preferably 1:3 to 3:1. The two M present in general formula (II) ＋Some of it is hydrogen ions, and some of it is sodium ions (Na ＋ Being one of the desirable characteristics is one of the characteristics.

[0036] Peptide-type biosurfactants, such as surfactant or surfactant salts, can be obtained by culturing a microorganism, such as a strain belonging to Bacillus subtilis, according to known methods, and isolating it from the culture medium. Refined products may be used, or unpurified products, such as the culture medium, may be used as is. Products obtained by chemical synthesis can also be used if they have the same molecular structure. Commercially available products can also be used.

[0037] The glycoside biosurfactant is not particularly limited as long as it has a glycolipid structure and surfactant properties, but examples include rhamnolipid, sophorolipid, mannosylerythritol lipid, cellobiose lipid, trehalose lipid, succinoyltrehalose lipid, glucose lipid, polyol lipid, oligosaccharide fatty acid esters, and salts thereof.

[0038] As the glycoside biosurfactant, at least one glycoside biosurfactant selected from rhamnolipid, sophorolipid, and salts thereof is preferred, and at least one glycoside biosurfactant selected from rhamnolipid, sophorolipid, and salts thereof is more preferred.

[0039] Glycosyl biosurfactants can be obtained according to known methods. Commercially available products can also be used.

[0040] As the biosurfactant, at least one biosurfactant selected from surfactant, rhamnolipid, sophorolipid, and salts thereof is particularly preferred.

[0041] <Glutathione> The composition of this embodiment may contain glutathione. The glutathione may be reduced glutathione (GSH, N-(N-γ-L-glutamyl-L-cysteinyl)glycine), oxidized glutathione (GSSG) formed by the linkage of two GSH molecules via a disulfide bond, or a mixture of GSH and GSSG. Glutathione is preferably GSSG.

[0042] Glutathione (GSSG or GSH) may encompass various forms, including free glutathione that is not bound to other substances and is not ionized, salts, hydrates, and mixtures of two or more of these.

[0043] When using GSSG as glutathione, it may be used as a mixture of GSSG and GSH, but it is preferable that the GSSG content is relatively higher than the GSH content. More preferably, the total weight of GSSG (calculated as free form) relative to the total weight of GSSG and GSH (calculated as weight of all free forms) is 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and most preferably 100% by mass.

[0044] The GSSG salt is not particularly limited as long as it is one or more salts that are acceptable as fertilizers, such as ammonium salts, calcium salts, magnesium salts, sodium salts, and lithium salts, but preferably it is one or more salts selected from ammonium salts, calcium salts, and magnesium salts. Examples of GSSG salts include 1-ammonium salt of GSSG, 0.5-calcium salt or 1-calcium salt of GSSG, 0.5-magnesium salt or 1-magnesium salt of GSSG, etc.

[0045] <Amino Acids> In this specification, "amino acid" means any agriculturally acceptable amino acid, preferably tryptophan. If the amino acid is an optically active amino acid, it may be the L-form, the D-form, or a mixture of the L-form and the D-form, preferably the L-form. The amino acid may be a single amino acid or a mixture of two or more amino acids. The most preferred amino acid is L-tryptophan.

[0046] Amino acids can encompass various forms, including free amino acids that are not bound to other substances and are not ionized, salts formed with amino acids and acids or bases, hydrates thereof, and mixtures thereof.

[0047] <Agriculturally Acceptable Carrier> The composition of this embodiment may contain an agriculturally acceptable carrier. In this specification, "agriculturally acceptable carrier" is any carrier capable of holding allantoin, and may be a liquid carrier or a solid carrier. Examples of solid carriers include hydrated solid materials. The solid carrier may be in the form of a powder or granules.

[0048] Preferably, the "agriculturally acceptable carrier" is a liquid carrier such as water or an organic solvent. Here, the water used as the carrier is not limited to pure water, but may be an aqueous solution, an aqueous suspension, an aqueous gel, or an aqueous slurry that has good viscosity. Similarly, the organic solvent is not limited to a pure organic solvent, but may be an organic solvent-based solution, suspension, gel, or slurry that has good viscosity. Examples of organic solvents include methyl ether, ethyl ether, propyl ether, and butyl ether.

[0049] Agriculturally acceptable carriers are preferably liquid carriers containing an aqueous solution in which a hydrateable substance is dissolved in water, or solid carriers containing a water-soluble hydrateable substance. Examples of hydrateable substances include polyvinylpyrrolidone, random and block copolymers of alkylene oxides, vinyl acetate / vinylpyrrolidone copolymers, alkylated vinylpyrrolidone copolymers, polyalkylene glycols including polypropylene glycol and polyethylene glycol, polyvinyl acetate, polyvinyl alcohol, gelatin, agar, gum arabic, karaya gum, tragacanth gum, guar gum, locust bean gum, xanthan gum, gatch gum, carrageenan, alginate, casein, dextran, pectin, chitin, 2-hydroxyethyl starch, 2-aminoethyl starch, 2-hydroxyethylcellulose, methylcellulose, carboxymethylcellulose salts, cellulose sulfate, polyacrylamide, alkali metal salts of malean anhydride copolymers, and alkali metal salts of poly(meth)acrylates.

[0050] <Composition for Disease Control> The composition of this embodiment can be applied to the target plant, but the method of application is not particularly limited, however it is especially preferable to use it to cover plant seeds. By treating the plant seeds, the germination rate from the seeds is improved and diseases during the initial growth period after germination are suppressed. Here, "initial growth" generally refers to the period from germination to the middle of the vegetative growth period when dry matter production begins to increase rapidly. For example, it refers to growth within 90 days, 60 days, 30 days, 25 days, 21 days, or 14 days after germination. Examples of application other than seed covering include application to plant leaves, roots, seeds, seedlings, fruits, etc. Examples of application to above-ground parts such as leaves, seedlings, and fruits include spraying or coating, and examples of application to underground parts such as roots include mixing into the soil. Hereinafter, unless otherwise specified, the composition of this embodiment will be exemplified as a composition for seed covering, but it is not intended to limit the scope of this embodiment to a composition for seed covering.

[0051] If the composition of this embodiment contains an agriculturally acceptable carrier, it may be liquid or solid depending on the form of the carrier. If the composition of this embodiment is a seed coating composition and is a liquid composition, plant seeds can be coated by immersing or spraying them with the liquid composition, and then dried as necessary after coating. If the composition of this embodiment is a seed coating composition and is a solid composition such as a powder, the dried solid composition may be brought into contact with the plant seeds to coat them, or the solid may be mixed with water to make it liquid or paste-like, which can then be brought into contact with the plant seeds to coat them, and then dried as necessary after coating.

[0052] The composition of this embodiment contains allantoin. The composition of this embodiment may further contain biosurfactant, glutathione and / or amino acids. If the composition of this embodiment contains biosurfactant, it is particularly preferable that the composition contains 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, of biosurfactant per 100 parts by weight of allantoin, with an upper limit of 1000 parts by weight or less, preferably 500 parts by weight or less, more preferably 250 parts by weight or less, per 100 parts by weight of allantoin. If the composition of this embodiment contains glutathione, it is particularly preferable that the composition contains 0.01 parts by weight or more, preferably 0.05 parts by weight or more, more preferably 0.10 parts by weight or more, of glutathione per 100 parts by weight of allantoin, with an upper limit of 50 parts by weight or less, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, per 100 parts by weight of allantoin. If the composition of this embodiment contains amino acids, the composition contains 0.009 parts by weight or more, preferably 0.0225 parts by weight or more, more preferably 0.045 parts by weight or more, of amino acids per 100 parts by weight of allantoin, with a particularly preferable upper limit of 50 parts by weight or less, preferably 20 parts by weight or less, and more preferably 18 parts by weight or less, per 100 parts by weight of allantoin.

[0053] The composition of this embodiment may further contain, as needed, one or more of the following additional additives. Additives include, but are not limited to, humectants, colorants, defoamers, UV protectants, antifreezes, preservatives, biological control agents or biocides, surfactants, emulsifiers, fillers, scavengers, plasticizers, phospholipids, fluidizers, fusion aids, waxes, and / or fillers (e.g., clay, talc, glass fiber, cellulose, pulverized wood, etc.).

[0054] The concentration of allantoin in the composition of this embodiment is not particularly limited. When the composition of this embodiment is a seed coating composition, the amount of the composition used to coat one ton of plant seeds preferably contains 2 g or more, more preferably 5 g or more, even more preferably 10 g or more, and particularly preferably 20 g or more of allantoin, with no particular upper limit, but preferably 1000 g or less, and more preferably 500 g or less.

[0055] 2. Coated Seeds A second embodiment of the present invention is coated seeds comprising a composition. The coated seeds of this embodiment are characterized in that they contain a composition comprising allantoin on their surface, thereby reducing the risk of microbial disease.

[0056] The coated seeds of this embodiment can be prepared by coating plant seeds with the plant disease control composition of the first embodiment of the present invention. Plants grown from the coated seeds of this embodiment have a reduced risk of microbial diseases.

[0057] In the coated seeds of this embodiment, the allantoin-containing composition present on the surface of the seed is typically the plant disease control composition of the first embodiment of the present invention itself, or a dried version of the plant disease control composition. In the coated seeds of this embodiment, the allantoin-containing composition is not necessarily present only on the surface of the seed, but may partially penetrate into the interior of the seed.

[0058] The allantoin content in the coated seeds of this embodiment is not particularly limited. The coated seeds of this embodiment preferably contain 2 g or more, more preferably 5 g or more, even more preferably 10 g or more, and most preferably 20 g or more of allantoin per ton, with no particular upper limit, but preferably 1000 g or less, and more preferably 500 g or less.

[0059] The coated seeds of this embodiment may contain, in addition to allantoin, biosurfactant, glutathione and / or amino acids on their surface. If the coated seeds of this embodiment contain biosurfactant, the seeds contain 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, of biosurfactant per 100 parts by weight of allantoin, with an upper limit of 1000 parts by weight or less, preferably 500 parts by weight or less, more preferably 250 parts by weight or less, per 100 parts by weight of allantoin. If the coated seeds of this embodiment contain glutathione, the seeds contain 0.01 parts by weight or more, preferably 0.05 parts by weight or more, more preferably 0.10 parts by weight or more, of glutathione per 100 parts by weight of allantoin, with an upper limit of 50 parts by weight or less, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, per 100 parts by weight of allantoin. When the coated seeds of this embodiment contain amino acids, the seeds contain 0.009 parts by weight or more, preferably 0.0225 parts by weight or more, and more preferably 0.045 parts by weight or more, of amino acids per 100 parts by weight of allantoin, with a particularly preferable upper limit of 50 parts by weight or less, preferably 20 parts by weight or less, and more preferably 18 parts by weight or less, per 100 parts by weight of allantoin.

[0060] 3. Method for preventing or reducing plant diseases caused by microorganisms The third embodiment of the present invention is a method for preventing or reducing plant diseases caused by microorganisms. The method of this embodiment is characterized by comprising sowing the coated seeds of the second embodiment of the present invention, and growing the plants from the coated seeds after sowing.

[0061] According to the method of this embodiment, it is possible to suppress the occurrence of plant diseases caused by plant pathogens, such as poor germination and wilting, and to cultivate plants with high yields.

[0062] In the method of this embodiment, the steps of sowing the coated seeds and growing the plants from the coated seeds after sowing can be carried out under conditions appropriately selected according to the plant.

[0063] The method of this embodiment may be used in combination with other control measures. Other control measures include: 1) chemical control such as sterilization and disinfection of seeds and soil using chemical pesticides, application of above-ground chemicals, fumigation, fumigation evaporation, and coating; 2) physical control and cultural control such as control of rare environments using rain shelters, windbreak nets, and ventilation fans, use of resistant varieties, crop transfer, etc., and disinfection of soil by heat such as sunlight, steam, and hot water; 3) biological control using antagonistic plants, antagonistic microorganisms, etc.; and 4) field hygiene management such as crop residue treatment, seed disinfection, cultivation of disease-free seedlings, and washing of agricultural machinery, materials, and footwear, as well as appropriate combinations thereof.

[0064] Chemical pesticides used for chemical control include, for example, copper fungicides (organocopper agents, nonylphenolsulfonate copper agents, DBEDC agents), organosulfur fungicides (zineb, maneb, manzeb, ambam, polycarbamate agents, propineb agents, dilam agents, thiram agents, thiadiazine agents), organophosphate fungicides (IBP agents, EDDP agents, triclophosmethyl agents, fosetyl agents), organochlorine agents (TPN agents), melanin biosynthesis inhibitors (fusalide agents, tricyclazole agents, pyroquilon agents, carpropamide agents), and benzimidazole fungicides (thiophanate-methyl agents, Benomyl, thiabenzol, dicarboxyimide fungicides (iprodione, procymidone), acid amide fungicides (mepronil, flutolanil, flametopyr, tifluzamide, metalaxyl, oxadixyl, fenhexamide, phenoxanil), sterol biosynthesis inhibitors (triadimefone, vitertanol, mycrobutanil, hexaconazole, tebuconazole, propiconazole, difenoconazole, ipconazole, imibenconazole, cyproconazole, triflumizole, prochlor Antibacterial agents (such as pefurazoates, phenalimol, pyrifenox, triforin, tetraconazole, oxpoconazole fumarate, fenbuconazole, simeconazole), methoxyacrylate fungicides (azoxystrobin, kresoximmethyl, metminostrobin, trifloxystrobin, famoxadone), anilinopyrimidine fungicides (mepanipyrim, cyprodinil, pyrimethanil), synthetic antibacterial agents (tecrophthalam, oxolinic acid), soil fungicides (fursulfamide, hydroxyisoxazoates) (Various agents, eclomazole, dazomet, chloroneb, metasulfocarb, methyl isothiocyanate, D-D, methyl bromide, chloropicrin, carbam, sodium carbam salt), antibiotics and fungicides (streptomycin, oxytetracycline, blastocydin S, kasugamycin, polyoxin, validamycin, mildiomycin), natural fungicides (machine oil, rapeseed oil), probenazole, isoprothiolane, ferimzone, diclomezin, pencyclon, fluorimide, captan,Sulfenic acid-based agents, dithianone-based agents, quinoxaline-based agents, diflumetrim-based agents, fludioxonil-based agents, bentazole-based agents, acibenzolar-S-methyl-based agents, triazine-based agents, fluazinam-based agents, diethofencarb-based agents, cymoxanil-based agents, iminoctadine acetate-based agents, iminoclazine albesilate-based agents, propamocarb hydrochloride-based agents, dimethomorph-based agents, diclocimet-based agents, famoxadone-based agents, cyazofamide-based agents, cyflufenamide-based agents, thiadinil-based agents, etc. can be used. The chemical pesticides used can be appropriately selected according to the plant species being cultivated and the microorganisms being controlled. Furthermore, the application method of the chemical pesticides can be appropriately set according to the type of chemical pesticide used, the plant species being cultivated, and the microorganisms being controlled. According to the method of this embodiment, even when using chemical pesticides, the amount used can be reduced compared to conventional amounts.

[0065] 4. Other Embodiments The present invention may include any other embodiments as long as they involve controlling microbial diseases of plants using a composition containing allantoin. For example, one embodiment of the present invention is a method of controlling plant diseases by applying a composition containing allantoin to the soil, or by spraying or coating it on leaves, stems, etc.

[0066] The present invention will be specifically described in the following examples, but the present invention is not limited to these examples. In the following description and referenced drawings, "ALN" refers to allantoin and "SF" refers to surfactant.

[0067] <Example 1> Cultivation of soybeans from coated seeds in Rhizoctonia-contaminated soil (1) 100 g of seed-coated soybean seeds (variety: Fukuyutaka) were coated with 800 μL of a coating solution containing allantoin, surfactin, and polyvinyl alcohol in water using a coating apparatus (manufactured by SATEC). Allantoin was used at a concentration of 0 g, 20 g, or 100 g per ton of seeds (MT-seed), and surfactin at a concentration of 0 g or 0.5 g, either alone or in combination. Treatment 1 = Allantoin 20 g / MT-seed Treatment 2 = Allantoin 100 g / MT-seed Treatment 3 = Allantoin 20 g / MT-seed + Surfactin 0.5 g / MT-seed

[0068] (2) Rhizoctonia disease assay: Sterilized barley seeds were inoculated with Rhizoctonia solani and cultured for 10 days at 30°C in the dark. This was used as the inoculum. Contaminated soil was prepared by mixing the aforementioned inoculum with Tsuchitaro (manufactured by Sumitomo Forestry Greening Co., Ltd.) at a weight ratio of 10%. Soybean seeds (variety: Fukuyutaka) were sown at a rate of 10 seeds / pot in the contaminated soil, and three pots were prepared for each treatment plot. The plants were cultivated in an artificial climate chamber (28°C / 12 hours during the light period, 25°C / 12 hours during the dark period), and 11 days after sowing, an evaluation index was determined using the following criteria. Based on this, the disease severity and control value were calculated using the following formula. (Evaluation Index) 0: Healthy 1: Slight waterlogged browning observed at the base of the plant 2: Waterlogged browning observed at the base of the plant, growth significantly delayed 3: Dead 4: Pre-emergence blight (failure to germinate) (Severity of disease) Severity of disease = [(0 x number of plants) + (1 x number of plants) + (2 x number of plants) + (3 x number of plants) + (4 x number of plants)] / (4 x total number of plants surveyed) x 100 (Control Value) Control Value = (1 - Severity of disease in treated area / Severity of disease in untreated area) x 100

[0069] Figure 1 shows photographs of soybeans 11 days after sowing in each test plot. Table 1 shows the number of germinated seedlings, disease severity, and control efficacy for each test plot. The results from Figure 1 and Table 1 show that disease severity decreased and the number of germinated seedlings and control efficacy improved in a manner dependent on the amount of allantoin added. Furthermore, it was shown that combining allantoin with surfactin improved the number of germinated seedlings and control efficacy. Since neither allantoin nor surfactin itself has bactericidal or disinfectant properties, it is suggested that they exert their plant disease control function through a mechanism different from conventional chemical pesticides.

[0070]

[0071] <Example 2> Cultivation of soybeans from coated seeds in Pythium-contaminated soil (1) 100 g of seed-coated soybean seeds (variety: Fukuyutaka) were coated with 800 μL of a coating solution containing allantoin and polyvinyl alcohol in water using a coating device (manufactured by SATEC). The coating treatment was carried out so that the amount of allantoin per ton of seeds (MT-seed) was 5 g, 10 g, or 15 g.

[0072] (2) Pythium disease assay Sterilized bentgrass seeds were inoculated with Pythium aphanidermatum and cultured for 5 days at 30°C in the dark, and this was used as the inoculum. Contaminated soil was prepared by mixing the aforementioned inoculum with Tsuchitaro (manufactured by Sumitomo Forestry Greening Co., Ltd.) at a weight ratio of 10%. Soybean seeds (variety: Fukuyutaka) were sown at a rate of 10 seeds / pot in the contaminated soil, and 3 pots were prepared for each treatment plot. The plants were cultivated in an artificial climate chamber (28°C / 12 hours during the light period, 25°C / 12 hours during the dark period), and 11 days after sowing, an evaluation index was determined using the following criteria, and based on this, the disease severity and control value were calculated using the following formula. (Evaluation Index) 0: Healthy 1: Root discoloration, growth significantly delayed 2: Dead 3: Pre-emergence blight (failure to germinate) (Severity of disease) Severity of disease = [(0 x number of plants) + (1 x number of plants) + (2 x number of plants) + (3 x number of plants)] / (3 x total number of plants surveyed) x 100 (Control Value) Control Value = (1 - Severity of disease in treated area / Severity of disease in untreated area) x 100

[0073] Figure 2 shows photographs of soybeans 11 days after sowing in each test plot. Table 2 shows the number of germinated seedlings, disease severity, and control efficacy for each test plot. The results in Figure 2 and Table 2 show that the allantoin-treated plots exhibited reduced disease severity, improved germinated seedling numbers, and enhanced control efficacy. Since allantoin itself does not have bactericidal or disinfectant properties, it is suggested that it exerts its plant disease control function through a mechanism different from that of conventional chemical pesticides.

[0074] All publications, patents, and patent applications cited herein shall be incorporated herein by direct reference.

Claims

1. A plant disease control composition containing allantoin as an active ingredient, for preventing or reducing plant diseases caused by microorganisms.

2. The composition according to claim 1, wherein the disease is caused by filamentous fungi or oomycetes.

3. The composition according to claim 2, wherein the disease is caused by a filamentous fungus, and the filamentous fungus belongs to the genus Rhizoctonia.

4. The composition according to claim 2, wherein the disease is caused by an oomycete, and the oomycete is of the genus Pythium.

5. The composition according to claim 1, wherein the disease is a soil-borne disease.

6. The composition according to claim 1, further comprising a biosurfactant.

7. The composition according to claim 6, wherein the biosurfactant is surfactant.

8. The composition according to claim 1, used for coating plant seeds.

9. Coated seeds containing a composition with allantoin on the surface, thereby reducing the risk of microbial disease.

10. The coated seed according to claim 9, wherein the coated seed contains 2 g or more of the allantoin per ton.

11. A method for preventing or reducing plant diseases caused by microorganisms, comprising sowing coated seeds as described in claim 9 or 10, and growing the plants from the coated seeds after sowing.

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