Plant growth aid, and method for growing plant

Abstract

The present invention addresses the problem of providing a plant growth aid which can achieve both the reduction of harmful effects thereof and the reduction of plant diseases at high levels.　The present invention is a plant growth aid containing particles having a volume average particle diameter of 10-1000 nm, wherein each of the particles contains a compound (X), copper, and chitosan as constituent components, and the compound (X) has at least two functional groups (x) that are of at least one type and are independently selected from the group consisting of a carboxyl group, a phosphoric acid group, and a sulfonic acid group, and salts thereof.

Description

Plant growth aid and plant growth method

[0001] The present invention relates to a plant growth aid and a plant growth method.

[0002] Chitosan is an N-deacetylated product of chitin, a basic polysaccharide with 2-amino-2-deoxy-D-glucol as one structural unit. It is known to have antibacterial, deodorizing, and moisturizing properties, and in recent years, its applications in various fields have been attempted. For example, wood preservatives and pest control agents based on complex salts of chitosan and a metal selected from copper, zinc, and silver are known (see Patent Documents 1 and 2). Furthermore, it is known that chitosan metal chelate complexes can be applied to plants to control agricultural crop diseases (Patent Document 3).

[0003] Meanwhile, in agricultural production worldwide, plant diseases caused by plant pathogens (fungi such as filamentous fungi, bacteria, viruses, etc.) are affecting food production. Plant diseases are one of the major factors that impair plant productivity, and controlling plant diseases could be expected to have a significant effect on increasing food production. Therefore, various control agents have been developed to protect crops from plant diseases. For example, to prevent plant diseases caused by infection with plant pathogens such as fungal and bacterial diseases, control agents such as inorganic and organic copper agents, control agents based on the antibiotics kasugamycin and streptomycin, strobilurin fungicides (QoI agents), and succinate dehydrogenase inhibitors (SDHI agents) are used. However, it has been pointed out that control agents such as antibiotics, QoI agents, and enzyme inhibitors can develop resistance within several years, making disease control difficult. On the other hand, while inorganic and organic copper agents have a low risk of developing resistance, they also have the problem of causing damage (phytotoxicity) to the appearance, function, quality, etc. of agricultural and horticultural crops.

[0004] Japanese Patent Publication No. 7-118970 Japanese Patent Application Laid-Open No. 2011-116723 International Publication No. 2000 / 032041

[0005] An object of the present invention is to provide a plant growth adjuvant which can reduce both plant diseases and phytotoxicity of the adjuvant itself at a high level.

[0006] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. Specifically, the present invention relates to a plant growth aid containing particles having a volume-average particle size of 10 to 1,000 nm, the particles comprising compound (X), copper, and chitosan as constituent components, wherein compound (X) is a compound having at least two functional groups (x) of at least one type selected from the group consisting of a carboxyl group, a phosphate group, a sulfonic acid group, and salts thereof.

[0007] When used during plant growth, the plant growth adjuvant of the present invention can reduce plant diseases and the phytotoxicity of the adjuvant itself at a high level.

[0008] The present invention provides a plant growth aid containing particles having a volume-average particle size of 10 to 1,000 nm, the particles comprising compound (X), copper, and chitosan as constituent components, wherein compound (X) is a compound having at least two functional groups (x), each of which is at least one type selected from the group consisting of a carboxyl group, a phosphate group, a sulfonic acid group, and salts thereof.

[0009] When conventional plant growth adjuvants contain copper, there is a problem that the plant growth adjuvants are likely to cause phytotoxicity to plants. However, the plant growth adjuvants of the present invention contain copper, but by containing compound (X) and chitosan as constituent components and forming particles with a volume average particle size of 10 to 1000 nm, it is possible to achieve a high level of both reduction in plant disease and reduction in phytotoxicity.

[0010] In this specification, the term "phytotoxicity" refers to the chlorosis symptoms that appear in plants and the accompanying death or leaf fall.

[0011] In the present invention, the compound (X) has a carboxyl group (—COOH), a phosphate group (—PO ４ H ２ ) and sulfonic acid groups (—SO ３The present invention includes a compound (X) having at least two functional groups (x) of at least one kind selected from the group consisting of chitosan, chitosan derivatives (H), and salts thereof. In the present invention, it is presumed that the amino groups in chitosan and the functional groups (x) in the compound (X) are crosslinked by bonding through electrostatic interaction or the like, thereby producing particles.

[0012] Examples of compound (X) include diphosphate, triphosphate (tripolyphosphate), polyphosphate, citric acid, xanthan gum, alginic acid, lignosulfonate, pectin, carrageenan, humic acid, fulvic acid, polyglutamic acid, carboxymethylcellulose, hyaluronic acid, dextran sulfate, chondroitin sulfate, polyacrylic acid, polymethacrylic acid, and salts thereof. Examples of salts include alkali metal (lithium, sodium, potassium, etc.) salts. From the viewpoint of achieving an appropriate particle size after crosslinking, compound (X) is preferably diphosphate, triphosphate (tripolyphosphate), or polyphosphate, more preferably tripolyphosphate or tripolyphosphate salt.

[0013] In the present invention, the particles contain copper. Copper may be contained in any manner as long as it is contained in the particles, but from the viewpoint of disease control effect, it is preferably contained in the particles as copper ions. Examples of methods for incorporating copper into particles include a method in which compound (X) is crosslinked with chitosan in the presence of an organic copper agent (e.g., 8-hydroxyquinoline copper, oxine copper, nonylphenolsulfonate copper, dodecylbenzenesulfonate bisethylenediamine copper complex (II), copper gluconate, etc.) and / or inorganic copper (e.g., copper acetate, copper carbonate, copper hydroxide, naphthene copper, copper oleate, copper oxychloride, copper silicate, copper sulfate, copper tallate, etc.) to form particles. As the copper compound, from the viewpoint of the likelihood of causing phytotoxicity, organic copper agents are preferred, and copper gluconate is more preferred.

[0014] In the present invention, the particles contain chitosan. From the viewpoint of antibacterial effect, the chitosan contained in the particles preferably has a viscosity-average molecular weight of 50,000 to 150,000. It is known that the molecular weight of chitosan is proportional to the viscosity of a chitosan solution. In the present invention, the viscosity-average molecular weight can be measured using an Ubbelohde viscometer. Specifically, chitosan is dissolved in a mixed solvent consisting of 0.2 M acetic acid, 0.1 M sodium chloride, and 4 M urea to prepare solutions with concentrations of 0.4, 0.2, 0.1, 0.05, and 0.025 wt %. The intrinsic viscosity [η] of each solution is determined from the viscosity measured at 25°C, and the viscosity-average molecular weight can be calculated using the Mark-Houwink-Sakurada equation (Equation 1). Here, the constants K and α are each 8.93 × 10 －２ cm ３ / g, 0.71. [η] = KMα (Equation 1)

[0015] In the present invention, the degree of deacetylation of chitosan is not particularly limited, but is preferably 70% or more, more preferably 75 to 85%, from the viewpoint of achieving an appropriate particle size and increasing the encapsulation rate of a drug (such as copper). The degree of deacetylation of chitosan can be measured, for example, by colloid titration. Specifically, chitosan is dissolved in 0.5% by weight of acetic acid, and colloid titration is performed using 1 / 400N potassium polyvinyl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) with toluidine blue as an indicator, and the number of moles of free amino groups is measured to calculate the degree of deacetylation.

[0016] In the present invention, the weight proportion of compound (X) in the particles is preferably 15 to 70% by weight, more preferably 15 to 60% by weight, still more preferably 15 to 50% by weight, and particularly preferably 15 to 25% by weight, based on the weight of the particles, from the viewpoints of particle stability, particle size, and particle size distribution.

[0017] In the present invention, the weight proportion of copper in the particles is preferably 0.1 to 15% by weight, more preferably 0.1 to 12% by weight, even more preferably 0.5 to 12% by weight, and particularly preferably 0.5 to 8% by weight, based on the weight of the particles, from the viewpoint of disease control and growth promotion effects.

[0018] In the present invention, from the viewpoint of disease control, the weight proportion of chitosan in the particles is preferably 20 to 79.9% by weight, more preferably 25 to 75% by weight, even more preferably 30 to 70% by weight, and particularly preferably 30 to 60% by weight, based on the weight of the particles.

[0019] In the present invention, the particles may further contain gluconic acid and / or a salt thereof as a constituent component. The gluconate salt is preferably copper gluconate, and the particles may contain the gluconate salt in the form of copper gluconate. From the viewpoint of disease control, the weight ratio of gluconate ions derived from gluconic acid and / or a salt thereof in the particles is preferably 60 wt % or less, more preferably 5 to 50 wt %, and particularly preferably 5 to 40 wt %, based on the weight of the particles.

[0020] The weight ratio of compound (X) to chitosan in the particles (compound (X) / chitosan) is preferably 0.35 to 0.45, more preferably 0.38 to 0.45, and particularly preferably 0.39 to 0.44, from the viewpoint of achieving an appropriate particle size.

[0021] The weight ratio of compound (X) to copper in the particles (compound (X) / copper) is preferably 2 to 35, more preferably 2 to 30, and particularly preferably 4 to 20, from the viewpoint of drug encapsulation efficiency.

[0022] The weight ratio of chitosan to copper in the particles (chitosan / copper) is preferably 5 to 80, particularly preferably 5 to 50, from the viewpoint of phytotoxicity reduction ability.

[0023] In the present invention, the ratio of the number of moles of the functional group (x) derived from the compound (X) to the number of moles of the amino group derived from chitosan in the particle (functional group (x) / -NH ２ From the viewpoint of the drug release rate from the particles, the ρ is preferably 0.45 to 0.55, more preferably 0.46 to 0.53, and particularly preferably 0.47 to 0.53.

[0024] From the viewpoint of particle stability, the nitrogen element content (Yn) in the particles, based on the weight of the particles, is preferably 1 to 10, more preferably 2 to 8, and particularly preferably 3 to 6. The nitrogen element content (Yn) in the particles can be measured using a nitrogen / sulfur analyzer (for example, "TS-2100H" manufactured by Mitsubishi Chemical Corporation).

[0025] Compound (X) has a phosphate group (-PO ４ H ２ ), the phosphorus content (Yp) in the particles, based on the weight of the particles, is preferably 1 to 20, more preferably 2 to 16, and particularly preferably 5 to 12, from the viewpoint of particle stability. The phosphorus content (Yp) in the particles can be measured by fluorescent X-ray analysis according to the method of JIS K 0119-1969.

[0026] In the present invention, the X-ray fluorescence of each element is measured in accordance with JIS K 0119-1969, but specifically, it can be measured as follows. The measurement equipment used is a wavelength-dispersive X-ray fluorescence analyzer "Axios" (manufactured by PANalytical) and the accompanying dedicated software "SuperQ ver. 5.3A" (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data. Rh is used as the anode of the X-ray tube, the measurement atmosphere is helium, and the measurement diameter (collimator mask diameter) is 30 mm. Light elements are detected with a gas flow detector, and heavy elements are detected with a xenon shield detector or scintillation detector. A measurement sample is prepared by attaching a Mylar film (manufactured by Spectris Inc.) to a 37.5 mm diameter measuring cup (manufactured by Spectris Inc.), and placing 5 g of the sample on the Mylar film and smoothing it flat. Measurements are performed under the above conditions, and elements are identified based on the peak positions of the obtained X-rays. The concentration is calculated from the counting rate (unit: cps), which is the number of X-ray photons per unit time. The phosphorus content (wt%) is calculated by quantitative analysis using the qualitative and quantitative analysis software "OMNIAN." The phosphorus channel is observed near a diffraction angle (2θ) of 89.31°. The X-ray counting rate (unit: cps) is measured. The acceleration voltage and current of the X-ray generator are set to 24 kV and 100 mA, respectively.

[0027] Compound (X) has a phosphate group (-PO ４ H ２ ), the ratio (Yp / Yn) of the phosphorus element content (Yp) to the nitrogen element content (Yn) in the particle is preferably 0.45 to 0.55, more preferably 0.46 to 0.53, and particularly preferably 0.47 to 0.53, based on the weight of the particle, from the viewpoint of drug release rate.

[0028] The particles of the present invention can be produced, for example, by the following method (1). (1) A method in which a solution (i) in which chitosan is dissolved and a solution (ii) in which copper and / or a copper compound and compound (X) are dissolved are mixed under stirring (preferably by adding solution (ii) dropwise to solution (i) while stirring), to produce solution (iii), and particles are formed by crosslinking chitosan and compound (X) in the solution. The solution containing the obtained particles may be used as is as a plant growth aid, or the particles may be collected by filtration to obtain a powder, which may be used as a plant growth aid.

[0029] The weight proportion of chitosan in the solution (i) is preferably 0.01 to 1.0% by weight based on the weight of the solution (i).

[0030] The weight proportion of the compound (X) in the solution (ii) is preferably 0.001 to 0.5% by weight based on the weight of the solution (ii).

[0031] The weight proportion of copper and / or copper compounds in the solution (ii) is preferably 0.001 to 2.0% by weight based on the weight of the solution (ii).

[0032] The weight ratio of compound (X) to chitosan in the solution (iii) (compound (X) / chitosan) is preferably 0.35 to 0.45, more preferably 0.38 to 0.45, from the viewpoint of obtaining an appropriate particle size. A ratio of 0.35 or more is preferred because the generated particles are less likely to aggregate. A ratio of 0.045 or less is preferred because the particle size of the generated particles is not too large and the particle size distribution is also appropriate.

[0033] The weight ratio of compound (X) to copper in the solution (iii) (compound (X) / copper) is preferably 2 to 35, more preferably 2 to 30, and particularly preferably 4 to 20, from the viewpoint of the drug encapsulation efficiency.

[0034] The weight ratio of chitosan to copper in the solution (iii) (chitosan / copper) is preferably 5 to 80, more preferably 5 to 50, from the viewpoint of phytotoxicity reduction ability.

[0035] The plant growth adjuvant of the present invention may contain the particles, and the formulation of the plant growth adjuvant of the present invention may take various forms depending on the application method, etc., as described below. Examples include liquid formulations such as emulsions, oils, aerosols, and flowable formulations in which the particles are dispersed, as well as wettable powders, water-soluble formulations, dusts, and granules containing the particles. When applied to plants by spraying or the like, a liquid formulation or a formulation that can be made into a liquid upon application is preferred. When applied to plants by spraying or the like, a formulation that can be made into a liquid upon application is preferred.

[0036] The plant growth adjuvant of the present invention may contain other optional components depending on the formulation, shape, etc., as long as the plant disease control effect is not impaired. Examples of other optional components include liquid carriers, spreading agents, emulsifiers, dispersants, fillers, extenders, binders, wetting agents, disintegrants, lubricants, diluents, excipients, amino acids, peptides, fertilizer elements, and naturally occurring components. Examples of liquid carriers include media capable of dispersing the particles, such as water; alcohols such as 1-propanol and butanol; polyhydric alcohols such as ethylene glycol and propylene glycol; and hydrocarbons such as xylene.

[0037] Surfactants and the like can be used as the spreading agent, emulsifier, and dispersant. Examples of surfactants include nonionic surfactants (e.g., polyalkylene glycol alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxyethylene hexitane fatty acid esters, sorbitan fatty acid esters, polyoxyethylene resin acid esters, and polyoxyethylene fatty acid esters), anionic surfactants (e.g., sodium higher alcohol sulfate, sodium polynaphthylmethanesulfonate, sodium dioctyl sulfosuccinate, sodium alkylbenzenesulfonate, and calcium ligninsulfonate), cationic surfactants (e.g., dialkyldimethylammonium polynaphthylmethanesulfonate and stearyltrimethylammonium chloride), silicon-based surfactants (e.g., polyoxyalkyleneoxypropylheptamethyltrisiloxane and polyoxyethylenemethylpolysiloxane), and amphoteric surfactants. Nonionic surfactants can also be used in combination with anionic or cationic surfactants.

[0038] The plant growth aid of the present invention may contain other active ingredients as long as the plant disease control effect is not impaired. For example, it can be used in combination with known agents to further enhance the plant disease control effect or to broaden the range of plant diseases to which it is applicable. It can also be used in combination with known insecticides, miticides, antibacterial agents, etc.

[0039] When the plant growth adjuvant of the present invention is a liquid formulation, the weight proportion of the particles is preferably 0.001 to 10 wt %, more preferably 0.05 to 5 wt %, and particularly preferably 0.01 to 5 wt %, based on the weight of the plant growth adjuvant. When the plant growth adjuvant of the present invention is a liquid formulation, the weight proportion of the liquid carrier is preferably 90 to 99.999 wt %, more preferably 95 to 99.95 wt %, and particularly preferably 95 to 99.9 wt % based on the weight of the plant growth adjuvant. When the plant growth adjuvant of the present invention is a liquid formulation, the weight proportion of the gluconate ion is preferably 10 wt % or less, more preferably 5 wt % or less, and particularly preferably 1 wt % or less, based on the weight of the plant growth adjuvant. When the plant growth supplement of the present invention is a liquid formulation, the weight proportion of components other than the particles and the liquid carrier is preferably 10% by weight or less, more preferably 3% by weight or less, based on the weight of the plant growth supplement.

[0040] The volume average particle diameter of the particles in the plant growth supplement of the present invention is 10 to 1,000 nm from the viewpoint of leaf penetration rate. If the particle diameter is less than 10 nm, it is difficult to prepare the particles and encapsulate the drug, and if the particle diameter exceeds 1,000 nm, it is difficult to penetrate from the leaf surface into the leaf when sprayed on the leaves. From the viewpoint of leaf penetration rate, the volume average particle diameter of the particles is preferably 100 to 500 nm. The volume average particle diameter of the particles can be measured for the plant growth supplement of the present invention by dynamic light scattering using a light scattering device [e.g., Zetasizer Ultra (manufactured by Malvern)].

[0041] When the plant growth adjuvant of the present invention is a liquid formulation, the polydispersity index of the particles in the plant growth adjuvant is preferably 0.5 or less, more preferably 0.4 or less. The polydispersity index can be measured by dynamic light scattering using a light scattering device [such as Zetasizer Ultra (manufactured by Malvern)] for the plant growth adjuvant at 25° C.

[0042] The plant growth adjuvant of the present invention can be produced as a plant growth adjuvant, for example, by using the above-mentioned method for producing particles.

[0043] The plant growth adjuvant of the present invention is a plant growth adjuvant that can simultaneously reduce plant diseases and the phytotoxicity of the adjuvant itself at a high level.

[0044] In the present invention, "plant disease" means a plant disease caused by a plant pathogen (virus, bacteria, fungus, etc.), and is not particularly limited, but examples include plant viral diseases caused by viruses that infect plants, plant bacterial diseases caused by bacteria that infect plants, and plant fungal diseases caused by fungi that infect plants.

[0045] In the present invention, the effect of reducing plant diseases includes the effect of suppressing or inhibiting infection by the pathogen, the effect of suppressing or inhibiting proliferation, growth or movement of the pathogen, and the effect of killing the pathogen.

[0046] Examples of "plant viral diseases" to which the plant growth aid of the present invention is applicable include diseases that develop due to infection with viruses of the genus Tobamovirus, Potexvirus, Carlavirus, Cucumovirus, Carmovirus, Potyvirus, Tospovirus, Crinivirus, or Begomovirus.

[0047] Examples of "Tobamovirus" include tomato mosaic virus (ToMV), tobacco mosaic virus (TMV), cucumber green mottle mosaic virus (KGMMV), pepper mild mottle virus (PMMoV), watermelon green mottle mosaic virus (CGMMV), tomato mottle virus (ToMMV), and tomato brown rugose fruit virus (ToBRFV). Examples of "Potexvirus" include plantain mosaic virus (PIAMV) and potato virus X (PVX), and examples of "Carlavirus" include potato virus M (PVM). Examples of "Cucumovirus" include cucumber mosaic virus (CMV), examples of "Carmovirus" include melon necrotic spot virus (MNSV), examples of "Potyvirus" include potato virus Y (PVY) and plum ringspot virus (PPV), examples of "Tospovirus" include watermelon grey mottle virus (WSMoV), examples of "Crinivirus" include cucurbit chlorotic yellows virus (CCYV), and examples of "Begomovirus" include tomato yellow leaf curl virus (TYLCV), but are not limited to these.

[0048] Examples of plant pathogenic bacteria include, but are not limited to, the genera Pseudomonas, Erwinia, Xanthomonas, Ralstonia, Streptomyces, Clavibacter, Agrobacterium, Curtobacterium, Acidovorax, and Burkholderia.

[0049] Specific examples of plant pathogenic bacteria include the bacterial black spot pathogen of cruciferous plants (Pseudomonas syringae pv. maculicola, Pseudomonas cannabina pv. alisalensis), the bacterial leaf spot pathogen of tomato (Pseudomonas syringae pv. tomato), the bacterial rot pathogen of lettuce (Pseudomonas cichorii, Pseudomonas marginalis, Pseudomonas viridiflava), and the bacterial borer pathogen of peach (Xanthomonas arboricola pv. pruni, Pseudomonas syringae pv. syringae, Brenneria nigrifluens, Erwinia nigrifluens), red clover bacterial leaf spot, adzuki bean bacterial brown spot, citrus bacterial brown spot, etc. (Pseudomonas syringae pv. syringae), soybean bacterial leaf spot (Pseudomonas savastanoi pv. glycinea), cucumber bacterial leaf spot (Pseudomonas syringae pv. lachrymans), tobacco wildfire blight (Pseudomonas syringae pv. tabaci), pea vine bacterial rot (Pseudomonas syringae pv. pisi), kiwifruit canker fungus (Pseudomonas syringae pv. actinidiae), soft rot fungus of Chinese cabbage, cabbage, radish, lettuce, etc. (Erwinia carotovora), rice bacterial leaf blight fungus (Xanthomonas oryzae pv. oryzae), soybean leaf burn fungus (Xanthomonas campestris pv. glycinea, Xanthomonas axonopodis pv. glycinea), black rot fungus of cruciferous plants such as cabbage and broccoli (Xanthomonas campestris pv. campestris), lettuce spot pathogen (Xanthomonas axonopodis pv. vitians), citrus canker pathogen (Xanthomonas citri subsp. citri),Tomato, eggplant, pepper, strawberry, and ginger bacterial wilt pathogen (Ralstonia solanacearum), potato scab pathogen (Streptomyces spp.), tomato canker pathogen (Clavibacter michiganensis subsp. michiganensis), crown gall pathogen of plants of the Asteraceae and Rosaceae families (Agrobacterium tumefaciens), melon hairy root pathogen (Agrobacterium rhizogenes), grapevine crown gall pathogen (Agrobacterium vitis, Rhizobium radiobacter), and kidney bean bacterial wilt pathogen (Curtobacterium flaccumfaciens pv. flaccumfaciens), tulip canker (Curtobacterium flaccumfaciens pv. oortii), watermelon fruit blotch fungus (Acidovorax avenae subsp. citrulli), rice brown stripe fungus and corn brown stripe fungus (Acidovorax avenae subsp. avenae), rice grain rot fungus (Burkholderia glumae), rice seedling blight fungus (Burkholderia plantarii), potato black leg fungus (Pectobacterium Examples of bacteria include, but are not limited to, Bacillus subtilis, Bacillus carotovorum, and Bacillus atrosepticum.

[0050] Examples of plant pathogenic fungi include the genus Colletotrichum, Phytophthora, Podosphaera, Sphaerotheca, Leveillula, Oidium, Oidiopsis, Erysiphe, Uncinula, Botrytis, Fusarium, Pyricularia, Fulvia, Pseudocercospora, Gibberella, and Monographella. Examples of bacteria that can be isolated include, but are not limited to, bacteria of the genera Pestalotiopsis, Corynespora, Puccinia, Alternaria, Plasmopara, Bremia, Peronospora, Cochliobolus, Rhizoctonia, Sclerotinia, Verticillium, Venturia, Monilinia, Cercospora, and Leptosphaeria.

[0051] Specific plant pathogenic fungi include, for example, Colletotrichum higginsianum, Colletotrichum orbiculare, Colletotrichum acutatum, Colletotrichum gloeosporioides species complex; C. aenigma, C. fructicola, C. siamense, Colletotrichum incanum, Colletotrichum dematium, and Colletotrichum spp., which cause anthracnose in radishes. gloeosporioides), grass anthracnose fungus (Colletotrichum graminicola), vegetable and other host plant anthracnose fungus (Colletotrichum spp.), potato and tomato late blight fungus (Phytophthora infestans), strawberry late blight fungus (Phytophthora nicotianae, Phytophthora cactorum, Phytophthora sp.), taro late blight fungus (Phytophthora colocasiae), vegetable, ornamental, tobacco, and other host plant late blight fungus (Phytophthora spp. ), strawberry powdery mildew (Podosphaera aphanis, Sphaerotheca aphanis, Sphaerotheca humuli), tomato powdery mildew (Levillula taurica, Oidium) sp., Oidium lycopersici, Oidium neolycopersici), cucumber powdery mildew (Sphaerotheca fuliginea, Sphaerotheca cucurbitae, Oidiopsis) sicula, Erysiphe polygoni, Oidium sp.), barley and wheat powdery mildew fungus (Erysiphe graminis), grape powdery mildew fungus (Erysiphe necator, Uncinula necator), pea powdery mildew fungus (Erysiphe pisi), pumpkin powdery mildew fungus (Sphaerotheca cucurbitae, Oidium citrulli),Eggplant powdery mildew (Erysiphe cichoracearum, Sphaerotheca fuliginea, Oidiopsis sicula), powdery mildew of vegetables, ornamentals, and other host plants, Botrytis cinerea of ​​tomatoes, strawberries, cucumbers, vegetables, grapes, and other host plants, Fusarium oxysporum f.sp.fragariae, rice blast (Pyricularia grisea (P. oryzae)), tomato leaf mold (Fulvia fulva), tomato leaf mold (Pseudocercospora fuligena), wheat head blight (Gibberella zeae, Fusarium avenaceum, Fusarium culmorum, Fusarium crookwellense, Monographella nivalis), tea ring spot fungus (Pestalothiopsis longiseta, Pestalotiopsis theae), soybean acute blight fungus (Fusarium tucumaniae, Fusarium virguliforme), cucumber brown spot fungus (Corynespora cassiicola), barley and wheat stem rust fungus (Puccinia graminis), barley and wheat stripe rust (Puccinia striiformis Westendorp var. striiformis), barley leaf rust (Puccinia hordei Otth), wheat leaf rust (Puccinia recondita Roberge ex Desmazieres), onion rust (Puccinia allii), chrysanthemum white rust (Puccinia horiana Hennings), rusts of coffee, pear, apple, peanut, vegetables, ornamental plants and other host plants, pear black spot (Alternaria alternata), cabbage black spot fungus (Alternaria brassicicola), Chinese cabbage black spot fungus (Alternaria brassicae, Alternaria brassicicola, Alternaria japonica), other vegetables (e.g.,Alternaria spp., which cause black spot on cucumber, cruciferous vegetables, apple, tomato, and other host plants; Plasmopara viticola, which causes lettuce downy mildew; Pseudoperonospora cubensis, which causes Chinese cabbage downy mildew; Peronospora parasitica, which causes downy mildew on soybean, tobacco, onion, and other host plants; Cochliobolus miyabeanus, which causes brown spot on rice; and Fusarium oxysporum f. sp., which causes cucumber fusarium wilt. cucumerinum), tomato wilt fungus (Fusarium oxysporum f. sp. lycopersici), rice seedling disease fungus (Gibberella fujikuroi), Rhizoctonia damping-off fungus of cucumber, eggplant, etc. (Rhizoctonia solani), tomato small grain rot fungus (Sclerotinia minor), potato verticillium wilt fungus (Verticillium albo-atrum, Verticillium dahliae, Verticillium nigrescens, Verticillium tricorpus), tomato ring spot fungus (Alternaria solani), Sclerotinia sclerotiorum, Venturia inaequalis, Monilinia fructicola, Cercospora kikuchii, Cercospora beticola, and Leptosphaeria nodorum are examples of fungi causing stem rot.

[0052] The plants to which the plant growth aid of the present invention is applied are not particularly limited as long as they are infected with the above-mentioned plant viruses, and examples thereof include solanaceae plants (tobacco, tomato, eggplant, potato, bell pepper, chili pepper, petunia, etc.), cucurbitaceae plants (cucumber, gourd, pumpkin, melon, watermelon, etc.), grassaceae plants (rice, barley, wheat, corn, sugarcane, sorghum, sorghum, turfgrass, etc.), Brassicaceae plants (chinese cabbage, cabbage, radish, bok choy, komatsuna, broccoli, rape, Arabidopsis, etc.), It can be applied to a wide range of plants, including legumes (soybeans, peanuts, peas, kidney beans, broad beans, etc.), Rosaceae (strawberries, apples, pears, peaches, plums, roses, cherry blossoms, etc.), Convolvulaceae (sweet potatoes, etc.), Liliaceae (leeks, onions, lilies, tulips, etc.), Asteraceae (lettuce, chrysanthemums, gerberas, etc.), Vitaceae (grapes, etc.), Caryophyllaceae (carnations, etc.), Orchidaceae (cattleyas, cymbidiums, etc.), Gentianaceae (lisianthus, etc.), and Plumbaceae (statica, etc.). For information on the relationship between plant pathogens and host plants, please refer to the Japan Plant Disease Name Database (Agricultural Biological Resources Genebank).

[0053] The method of applying the plant growth adjuvant of the present invention to plants is not particularly limited, and examples include spraying, coating, immersion, etc. When spraying the plant growth adjuvant of the present invention to plants, foliar application is preferred. It is also possible to add the plant growth adjuvant to the soil if the target plant is grown in soil, or to the hydroponic solution if the target plant is grown hydroponically. When plant tissue culture is performed, addition to the medium is also possible. Since a very high control effect is observed in the area where the plant growth adjuvant of the present invention is applied, preferred application methods include application to the entire plant body or leaves by spraying or coating, application to the roots by soil drenching, incorporation into the soil or hydroponic solution, or immersion into seeds, bulbs, etc. The plant growth adjuvant of the present invention is advantageous in that it can also exhibit a plant disease control effect in areas surrounding the application site.

[0054] The application time of the plant growth adjuvant of the present invention to plants is not particularly limited, but preventive control is most effective. Specifically, application from the seedling stage to before harvest is effective. In addition, there is no particular limit to the number of times the plant growth adjuvant is applied.

[0055] The plant growth adjuvant of the present invention is useful because, when applied to plants by the above-mentioned method, it can simultaneously reduce disease damage and phytotoxicity of the adjuvant itself at a high level.

[0056] This specification describes the following inventions:

[0057] The present invention (1) is a plant growth aid containing particles having a volume average particle size of 10 to 1000 nm, the particles comprising compound (X), copper, and chitosan as constituent components, and the compound (X) is a compound having at least two functional groups (x) of at least one type selected from the group consisting of a carboxyl group, a phosphate group, a sulfonic acid group, and salts thereof.

[0058] The present invention (2) is the plant growth enhancer according to the present invention (1), wherein the particles further contain gluconic acid and / or a salt thereof as a constituent component.

[0059] The present invention (3) is the plant growth supplement according to the present invention (2), in which the weight proportion of the copper is 0.1 to 15 wt %, the weight proportion of the chitosan is 20 to 79.9 wt %, the weight proportion of the compound (X) is 15 to 25 wt %, and the weight proportion of the gluconate ions derived from gluconic acid and / or a salt thereof is 5 to 40 wt %, based on the weight of the particles.

[0060] The present invention (4) is the plant growth supplement according to any one of the present inventions (1) to (3), wherein the weight ratio of the compound (X) to the copper in the particles (compound (X) / copper) is 2 to 35.

[0061] The present invention (5) is the plant growth enhancer according to any one of the present inventions (1) to (4), wherein the weight ratio of the compound (X) to the chitosan in the particles (compound (X) / chitosan) is 0.35 to 0.45.

[0062] The present invention (6) is the plant growth enhancer according to any one of the present inventions (1) to (5), wherein the weight ratio of chitosan to copper in the particles (chitosan / copper) is 5 to 80.

[0063] The present invention (7) is a method for producing a chitosan particle having a molecular weight of 1000 or more, the molecular weight of which is ... ２ ) is 0.45 to 0.55.

[0064] The present invention (8) is a method for growing plants, which uses the plant growth adjuvant according to any one of the present inventions (1) to (7).

[0065] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, "parts" means "parts by weight."

[0066] Examples and Comparative Examples: Production of Plant Growth Adjuvant (1) Chitosan [chitosan low molecular weight (Sigma-Aldrich), molecular weight: 100,000] was dissolved in a 0.1% by volume aqueous acetic acid solution to obtain the chitosan weight percentage shown in Table 1, thereby obtaining a chitosan aqueous solution (Liquid 1). (2) Tripolyphosphate (hereinafter sometimes abbreviated as TPP) and copper gluconate were dissolved in water to the concentrations shown in Table 1, thereby obtaining a copper gluconate-TPP aqueous solution (Liquid 2). In Table 1, the "gluconic acid content" and "copper content" in "Liquid 2" refer to the content converted from the copper gluconate used. (3) The chitosan aqueous solution (Liquid 1) obtained in (1) was stirred at 600 rpm in an amount shown in Table 1, and the copper gluconate-TPP aqueous solution (Liquid 2) obtained in (2) was added dropwise in an amount shown in Table 1 to obtain a plant growth supplement containing particles. Note that the obtained copper gluconate solution was used as is in Comparative Example 2-2 and Comparative Example 3-2.

[0067]

[0068] The plant growth aids prepared in each Example and Comparative Example were evaluated for particle size, encapsulated drug concentration, phytotoxicity reducing effect, and disease control effect by the following methods.

[0069] <Volume average particle size measurement> The volume average particle size of the particles in the plant growth aids prepared in each Example and Comparative Example was measured by dynamic light scattering using a light scattering device (Zetasizer Ultra, manufactured by Malvern). The results are shown in Table 1.

[0070] <Polydispersity Index> The polydispersity index of the particles in the plant growth supplements prepared in each Example and Comparative Example was measured using a light scattering device (Zetasizer Ultra, manufactured by Malvern) in an environment of 25° C. The results are shown in Table 1.

[0071] <Measurement of copper content in particles> (1) 400 μL of the plant growth aid was ultrafiltered using Amicon Ultra-0.5 10 kDa (manufactured by Merck) (4°C, 15,000 rpm, 60 minutes). This operation allowed components not encapsulated in the particles to pass through the filtration membrane. (2) 50 μL of a 1 wt% ascorbic acid solution was added to 100 μL of the filtrate that had passed through the filtration membrane to measure the copper content. ２＋ Cu ＋ (3) 4 mM bathocuproine (Cu ＋ Add 50 μL of a coloring agent solution of Cu contained in the filtrate. ＋ (4) The absorbance at 485 nm was measured using an absorptiometer, and the copper concentration in the filtrate was calculated. (5) The copper encapsulation rate in the particles was calculated from the amount of copper used in producing the plant growth supplement, the copper concentration in the filtrate obtained in (4) above, and the amount of the filtrate. The results are shown in Table 1.

[0072] <Contents of Chitosan and TPP in Particles> It was assumed that all chitosan and TPP used were converted into particles, and the contents are shown in Table 1.

[0073] <Gluconic Acid Content in Particles> (1) 0.9 mL of the plant growth supplement was mixed with ultrapure water, a 200 ppm gluconic acid aqueous solution, and a 20 ppm internal standard aqueous solution according to Table 2. Tetraethylene glycol was used as the internal standard. (2) 500 μL of the prepared sample was ultrafiltered using an Amicon Ultra-0.5 10 kDa (Merck) at 4°C, 15,000 rpm, for 60 minutes. This procedure allowed components not encapsulated in the particles and added components to pass through the filtration membrane. (3) The filtrate that passed through the filtration membrane was measured by LCMS, and the gluconic acid concentration in the filtrate was calculated using the standard addition method. (4) The gluconic acid encapsulation rate in the particles was calculated from the amount of gluconic acid used to produce the plant growth supplement, the gluconic acid concentration in the filtrate obtained in (3), and the amount of filtrate. The results are shown in Table 1.

[0074]

[0075] <Evaluation> (1) Evaluation of plant diseases and phytotoxicity of the growth adjuvant itself Tomatoes (variety: Regina), a plant of the Solanaceae family, were used as plant material and sown in soil (Supermix A (Sakata Seed Co., Ltd.): White vermiculite (A-2, Asahi Kogyo Co., Ltd.): Pacific Perlite Obsidian Series No. 3 (Pacific Material Co., Ltd.) = 2:1:1) and cultivated at 24°C under a 24-hour light / dark cycle (16 hours light and 8 hours dark). The plant growth adjuvants of Examples 1 to 4 and Comparative Examples 1 to 6 were sprayed on the leaves of tomatoes cultivated for 18-19 days after sowing. Furthermore, 0.1% by weight of Approach BI (Maruwa Biochemical Co., Ltd.) was added as a spreading agent to each solution. The control group was treated with ion-exchanged water containing 0.1% by weight of Approach BI. Two days after treatment, the tomato bacterial leaf spot pathogen Pseudomonas sp. (5 x 10 ６cfu / mL) was sprayed and inoculated, and the plants were allowed to stand in a moist chamber, and symptoms were examined 5 or 6 days after inoculation. Based on the obtained disease symptoms, the control titer was calculated as follows. For the obtained control titer, "(1-1) Evaluation of plant disease" of Comparative Example 1 was expressed as a relative value when the control titer of Example 1 was set to 100. Similarly, "(1-1) Evaluation of plant disease" of Comparative Examples 2-1 and 2-2 was expressed as a relative value when the control titer of Example 2 was set to 100. Furthermore, "(1-1) Evaluation of plant disease" of Comparative Examples 3-1 and 3-2 was expressed as a relative value when the control titer of Example 3 was set to 100. "(1-1) Evaluation of plant disease" of Comparative Example 4 was expressed as a relative value when the control titer of Example 4 was set to 100. Furthermore, phytotoxicity of the growth adjuvant itself was evaluated according to the following criteria. The results are shown in Table 1. The control values ​​of Comparative Examples 5 and 6 were recorded as "-" because the phytotoxicity was so severe that it was impossible to determine whether it was a disease symptom or phytotoxicity, and therefore evaluation was not possible.

[0076] (1-1) Evaluation of plant disease (control value) The control value is expressed by the following formula: Control value = {1 - (disease incidence in treated area / disease incidence in control area)} x 100

[0077] The severity of the disease is expressed by the following formula: Severity of the disease = {(1n １ +2n ２ +3n ３ +4n ４ +5n ５ ) / (5 x number of surveys) x 100 where n １ From n ５ The number indicates the number of individuals. The disease survey was conducted by dividing the degree of disease into the following five categories: 0: No symptoms 1: Minute spots 2: Symptoms are observed on less than 25% of the leaf area 3: Symptoms are observed on 25% to less than 50% of the leaf area 4: Symptoms are observed on 50% or more of the leaf area 5: Dead or defoliated

[0078] (1-2) Evaluation of phytotoxicity of the growth aid itself The criteria for phytotoxicity are as follows: 0: No phytotoxicity 1: Phytotoxicity observed on less than 25% of the leaf area 2: Phytotoxicity observed on 25% to less than 50% of the leaf area 3: Phytotoxicity observed on 50% or more of the leaf area 4: Withering or defoliation

[0079] The results in Table 1 show that the plant growth adjuvants of Examples 1 to 4 suppressed disease infection more effectively than the plant growth adjuvants of Comparative Examples 1, 2-1, 3-1, and 4 (containing no copper gluconate) or Comparative Examples 2-2 and 3-2 (copper gluconate solution). Furthermore, the plant growth adjuvants of Comparative Examples 5 and 6, which had a volume average particle size exceeding 1000 nm, exhibited extremely low disease infection suppression effects. Furthermore, while almost no phytotoxicity was observed when the plant growth adjuvants of Examples 1 to 4 were used, the plant growth adjuvants of Comparative Examples 2-2 and 3-2 (copper gluconate solution) caused slight white spots and chlorosis (phytotoxicity) on tomato leaves, and the plant growth adjuvants of Comparative Examples 5 and 6, which had a volume average particle size exceeding 1000 nm, caused browning and wilting of tomato leaves, resulting in an evaluation of "withering or defoliation." In other words, phytotoxicity was extremely severe.

[0080] The plant growth adjuvant of the present invention is useful because, when sprayed onto leaves, it can simultaneously reduce disease damage and phytotoxicity of the adjuvant itself at a high level.

Claims

1. A plant growth aid containing particles having a volume average particle size of 10 to 1,000 nm, the particles comprising compound (X), copper, and chitosan as constituent components, wherein compound (X) is a compound having at least two functional groups (x) of at least one type selected from the group consisting of a carboxyl group, a phosphate group, a sulfonic acid group, and salts thereof.

2. The plant growth aid according to claim 1, wherein the particles further contain gluconic acid and / or a salt thereof as a constituent component.

3. The plant growth supplement according to claim 2, wherein the weight percentage of copper is 0.1 to 15% by weight, the weight percentage of chitosan is 20 to 79.9% by weight, the weight percentage of compound (X) is 15 to 25% by weight, and the weight percentage of gluconate ions derived from gluconic acid and / or a salt thereof is 5 to 40% by weight, based on the weight of the particles.

4. The plant growth supplement according to claim 1, wherein the weight ratio of compound (X) to copper in the particles (compound (X) / copper) is 2 to 35.

5. The plant growth promoter according to claim 1, wherein the weight ratio of compound (X) to chitosan in the particles (compound (X) / chitosan) is 0.35 to 0.

45.

6. The plant growth promoter according to claim 1, wherein the weight ratio of chitosan to copper in the particles (chitosan / copper) is 5 to 80.

7. The ratio of the number of moles of the functional group (x) contained in the compound (X) to the number of moles of the amino group contained in the chitosan in the particle (functional group (x) / -NH ２ 2. The plant growth promoter according to claim 1, wherein the value of (A) is 0.45 to 0.

55.

8. A method for growing plants using the plant growth aid according to any one of claims 1 to 7.

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