Control agents for plant virus diseases

Abstract

To identify a compound having excellent control effect on plant virus disease and provide a control agent and a method for controlling plant virus disease by using the compound.SOLUTION: It has been found out that glycine has control effect on plant virus disease. Furthermore, it has been clarified that a metal chelated with glycine, a mixture of glycine and a metal compound, or a mixture of glycine and proanthocyanidin have markedly high control effect compared with the single use of glycine and the like.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an agent for controlling plant viral diseases, and more particularly to an agent for controlling plant viral diseases containing glycine, and a method for controlling plant viral diseases comprising applying the agent to plants. [Background technology]

[0002] Plant diseases caused by fungal diseases, bacterial diseases, plant viruses, etc. are causing losses in global agricultural production of up to 15%, of which the amount of crop production lost due to plant virus diseases is estimated to exceed 6 trillion yen per year. Plant virus diseases cause various abnormalities in agricultural crops, causing great damage to yield and quality.

[0003] In Japan, Lentemin is registered as an agricultural chemical to control plant viral diseases (Lentemin is a registered trademark of Noda Shokukin Kogyo Co., Ltd. Agricultural Chemical Registration Nos. 15584, 17774, 19439, and 19440). However, there is no specific chemical agricultural chemical. Therefore, the damage caused by plant viral diseases is reduced by controlling vectors, attenuated viruses, resistant varieties, and cultural control.

[0004] Under such circumstances, there is a strong demand for the development of a control agent that is highly effective against plant viral diseases, and for example, it has been reported that amino acid fermentation by-products, dehydroascorbic acid, ascorbic acid (vitamin C), etc. are effective against the disease (Patent Documents 1 to 3). The present inventors have also revealed that lignin extracts, metal chelates such as zinc gluconate, and proanthocyanidins are effective in controlling plant viral diseases (Patent Documents 4 to 6). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 065439 [Patent Document 2] JP 2014-5232 A [Patent Document 3] Patent No. 5574266 [Patent Document 4] International Publication No. 2017 / 125993 [Patent Document 5] Patent No. 6634325 [Patent Document 6] JP 2020-2016 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to identify a compound having an excellent control effect against plant viral diseases, and to provide a control agent and a control method for plant viral diseases utilizing the compound. [Means for solving the problem]

[0007] Means of the Invention The present inventors have conducted extensive research to achieve the above object and have found that glycine has a controlling effect against plant viral diseases.

[0008] Furthermore, it was revealed that metals chelated with glycine (e.g., zinc glycine) and mixtures of glycine and metal compounds (mixtures of glycine and zinc sulfate, copper sulfate, or iron (II) sulfate) each exhibit a higher control effect than when glycine or these metal compounds are applied alone. It was also revealed that mixtures of glycine and proanthocyanidins also exhibit a higher control effect than when these are applied alone. Furthermore, it was revealed that the control effect is exerted not only on the area directly treated with glycine, etc., but also on the surrounding areas.

[0009] They also found that no phytotoxicity occurs in plants when using a metal chelated by glycine, a mixture of glycine and a metal compound, or a mixture of glycine and proanthocyanidin, and thus completed the present invention.

[0010] That is, the present invention relates to a plant viral disease control agent containing glycine as an active ingredient, and a method for controlling a plant viral disease which comprises applying the control agent to a plant, and more specifically, provides the following inventions. (1) A plant viral disease control agent containing glycine. (2) The control agent according to (1), further comprising a metal or a compound containing the metal. (3) The control agent according to (1) or (2), wherein the metal is at least one metal selected from the group consisting of zinc, copper, and iron. (4) The control agent according to any one of (1) to (3), wherein the metal and the glycine form a metal chelate. (5) The control agent according to any one of (1) to (4), wherein the metal chelate is at least one metal chelate selected from the group consisting of zinc glycine, copper glycine, and iron glycine. (6) The control agent according to any one of (1) to (5), further comprising a compound containing proanthocyanidin. (7) The control agent according to any one of (1) to (6), wherein the plant viral disease is a mosaic disease. (8) A method for controlling a plant viral disease, comprising applying the control agent according to any one of (1) to (7) to a plant. Effect of the Invention

[0011] According to the present invention, it is possible to safely control plant viral diseases without causing phytotoxicity such as the occurrence of spots on leaves, wilting, and growth inhibition. [Brief description of the drawings]

[0012] [Figure 1A] 1 is a graph showing the control effect against Tomato mosaic virus (ToMV) in N. benthamiana leaves sprayed with 2 mM glycine, 1 mM zinc glycine, 1 mM zinc sulfate and 2 mM glycine, or 1 mM zinc gluconate. [Figure 1B] 1 is a graph showing the control effect against ToMV in N. benthamiana leaves foliar sprayed with 10 mM glycine, 1 mM zinc sulfate and 2 mM glycine, or 1 mM zinc sulfate and 10 mM glycine. [Diagram 2] 1 is a graph showing the control effect against ToMV in N. benthamiana leaves sprayed with 1 mM copper sulfate, 1 mM copper sulfate and 2 mM glycine, 2 mM copper sulfate and 4 mM glycine, 1 mM ferrous sulfate, or 1 mM ferrous sulfate and 2 mM glycine. [Diagram 3] 1 is a graph showing the control effect against ToMV in N. benthamiana leaves foliar sprayed with 333 ppm proanthocyanidins, or 333 ppm proanthocyanidins and 2 mM glycine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Pest control agent> As shown in the Examples below, it has been revealed that glycine has a controlling effect against plant viral diseases. Therefore, the present invention provides a plant viral disease control agent containing glycine.

[0014] (About Glycine) "Glycine" contained as an active ingredient in the control agent of the present invention means a compound that has the simplest form among amino acids and is also called aminoacetic acid or glycocol. Glycine may be contained in the form of a salt in the control agent of the present invention. Such salts are not particularly limited as long as they have a control effect against plant virus diseases, and examples thereof include acid addition salts, ammonium salts, and organic amine addition salts. More specifically, examples of acid addition salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, and phosphate, and organic acid salts such as acetate, maleate, fumarate, citrate, malate, lactate, α-ketoglutarate, gluconate, and caprylate. Examples of ammonium salts include salts of ammonium and tetramethylammonium. Examples of organic amine addition salts include salts of morpholine and piperidine.

[0015] The glycine used in the present invention is not particularly limited as long as it has a control effect against plant viral diseases, and may be a naturally derived purified product or a compound artificially synthesized by chemical synthesis, fermentation, or the like. The purified product may be a completely purified product or a crudely purified product. Furthermore, it may be available by purchasing it as a commercial product.

[0016] (Metals, etc.) As shown in the examples described later, the use of glycine in combination with a metal makes it possible to control plant viral diseases more significantly than the use of glycine alone. Therefore, the control agent of the present invention may be in an embodiment that further contains a metal or a compound containing the metal in addition to the above-mentioned glycine.

[0017] The "metal" that may be contained in the control agent of the present invention is not particularly limited as long as the control agent can exert its effect, and also includes metalloids. Examples of metals according to the present invention include zinc, copper, iron, potassium, manganese, molybdenum, magnesium, silicon, boron, calcium, cobalt, and nickel. Among these, zinc, copper, and iron are preferable because they are essential elements for plant growth and have low toxicity to plants.

[0018] The "compound containing a metal" is not particularly limited as long as the control agent of the present invention can exhibit its effect, and examples include sulfates, nitrates, organic acid salts, perhalogenates, hypohalites, phosphates, acetates, carbonates, oxides, hydroxides, halides (chlorides, etc.), acid halides, and alkoxides of the metals.

[0019] Glycine also has both an amino group and a carboxyl group, and has the effect of dissolving divalent metal salts by the chelation action of glycine. Therefore, by taking the form of a metal chelate, it becomes easier for plants to absorb it. Also, if metal ions are applied to the soil as they are (inorganic), the metal ions may combine with phosphoric acid and the like in the soil to form insoluble precipitates, making it difficult to achieve the desired effect. Therefore, by combining with glycine in advance to prepare a metal chelate and applying it, it is possible to prevent the metal ions from combining with other components and make it easier to achieve the above-mentioned effect.

[0020] From these viewpoints, therefore, it is preferable that in the control agent of the present invention, glycine and a metal are contained in the form of a metal chelate formed therefrom, and it is more preferable that the control agent of the present invention contains at least one of zinc glycine, copper glycine, and iron glycine.

[0021] In the present invention, the metals, metal-containing compounds and metal chelates may be used alone or in combination of two or more.

[0022] (About proanthocyanidins) As shown in the examples below, by using it in combination with proanthocyanidin, it is possible to more significantly control plant virus diseases than by using glycine alone. Therefore, the control agent of the present invention may be an embodiment that further contains a compound containing proanthocyanidin in addition to the above-mentioned glycine, etc.

[0023] In the present invention, "proanthocyanidin" refers to a compound in which multiple flavan-3-ols such as catechin and epicatechin are bonded. The proanthocyanidin used in the present invention is not particularly limited as long as it has a plant virus disease control effect, and may be an artificially synthesized compound, but the preferred form of proanthocyanidin in the present invention is a naturally derived purified product (plant purified product) extracted and purified from shell ginger of the genus Alpinia of the Zingiberaceae family. The purified product may be a completely purified product or a crude purified product.

[0024] Such purification can be performed by those skilled in the art with reference to the methods described in International Publication No. 2017 / 125993, Patent Document 6, etc. For example, purification can be performed by physically crushing the plant using a crusher. Furthermore, the purification of proanthocyanidins can include extraction with ethanol or elution with acetonitrile. When extraction with ethanol is performed, the ethanol concentration is usually 40% to 80%, preferably 60% to 80%. On the other hand, when elution with acetonitrile is performed, the acetonitrile concentration is usually 5% or more, preferably 5% to 30%, and more preferably 5% to 20%. Acetonitrile with a concentration of 40% or more may be used, but it is considered that the proportion of inactive components in the extract will increase.

[0025] The purified proanthocyanidin (extract) thus obtained can contain, for example, a fraction with a molecular weight of 3500 (e.g., a fraction with a molecular weight of 4000 or more, 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, or 10000 or more). This allows the removal of low molecular weight components that do not contribute to the control activity of plant diseases. The purified proanthocyanidin (extract) usually contains proanthocyanidin at 0.1 mg / ml or more, preferably 0.3 mg / ml or more, more preferably 0.5 mg / ml or more (e.g., 1 mg / ml or more, 5 mg / ml or more, 10 mg / ml or more, 20 mg / ml or more). In order to avoid negative effects such as chemical damage, it is generally considered that 50 mg / ml or less is preferable. A purified proanthocyanidin usually contains proanthocyanidin at a dry weight of 1% or more, preferably 5% or more, more preferably 10% (e.g., 20% or more, 30% or more, 50% or more). In the present invention, proanthocyanidins can be used alone or in combination of two or more kinds.

[0026] (Other ingredients) The formulation of the control agent of the present invention can take various forms depending on the application method described below. For example, in addition to liquid formulations such as emulsions, oils, aerosols, and flowables, wettable powders, water-soluble powders, powders, granules, tablets, etc., can be mentioned. When applied to a plant body by spraying, etc., a liquid formulation or a formulation that can be made into a liquid form at the time of application is preferable.

[0027] Depending on the formulation type, shape, etc., the control agent of the present invention may contain other optional components as long as the control effect against plant virus diseases is not impaired. Examples of other optional components include carriers, spreading agents, emulsifiers, dispersants, fillers, extenders, binders, wetting agents, disintegrants, lubricants, diluents, and excipients.

[0028] Examples of the liquid carrier include a solvent for dissolving or dispersing the glycine, etc., such as water, alcohols such as 1-propanol and butanol, polyhydric alcohols such as ethylene glycol and propylene glycol, and hydrocarbons such as xylene, etc. Examples of the solid carrier include kaolin, attapulgite, bentonite, calcium carbonate, talc, and zeolite.

[0029] A surfactant is usually used as the spreading agent, emulsifier and dispersant. Examples of the "surfactant" include nonionic surfactants (e.g., polyalkylene glycol alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyalkylene fatty acid ester, polyoxyethylene hexitane fatty acid ester, sorbitan fatty acid ester, polyoxyethylene resin acid ester, polyoxyethylene fatty acid ester), anionic surfactants (e.g., sodium higher alcohol sulfate, sodium polynaphthylmethanesulfonate, sodium dioctyl sulfosuccinate, sodium alkylbenzenesulfonate, calcium ligninsulfonate, etc.), cationic surfactants (e.g., dialkyldimethylammonium polynaphthylmethanesulfonate, stearyltrimethylammonium chloride), silicon-based surfactants (e.g., polyoxyalkyleneoxypropylheptamethyltrisiloxane, polyoxyethylenemethylpolysiloxane), amphoteric surfactants, etc. The nonionic surfactants can also be used in combination with anionic surfactants or cationic surfactants.

[0030] In the control agent of the present invention, other active ingredients may be contained in addition to the above-mentioned glycine, metals and compounds containing them, and proanthocyanidins, as long as the control effect against plant virus diseases is not inhibited.For example, in order to further enhance the control effect against plant virus diseases or to expand the range of plant diseases to be applied, it can be used in combination with known drugs such as lentemin.In addition, since there are cases where plant viruses are transmitted by insects, it can also be used in combination with known insecticides, miticides, antibacterial agents, etc.

[0031] <Control method> The present invention also provides a method for controlling a plant viral disease, which comprises applying the above-mentioned control agent to a plant.

[0032] Examples of plant viral diseases to which the control agent of the present invention can be applied include diseases caused by infection with a virus of the genus Tobamovirus, Potexvirus, Carlavirus, Cucumovirus, Carmovirus, Potyvirus, or Begomovirus.

[0033] Examples of viruses belonging to the genus Tobamovirus include tomato mosaic virus (ToMV), tobacco mosaic virus (TMV), cucumber green mottle mosaic virus (KGMMV), pepper mild mottle virus (PMMoV), and watermelon green mottle mosaic virus (CGMMV). Examples of viruses belonging to the genus Potexvirus include plantago mosaic virus (PlAMV) and potato X virus (PVX), and examples of viruses belonging to the genus Carlavirus include potato M virus (PVM). Examples of viruses belonging to the genus Cucumovirus include cucumber mosaic virus (CMV), and examples of viruses belonging to the genus Carmovirus include melon necrotic spot virus (MNSV). Examples of viruses belonging to the genus Potyvirus include potato virus Y (PVY) and plum ring virus (PPV), and examples of viruses belonging to the genus Begomovirus include, but are not limited to, tomato yellow leaf curl virus (TYLCV).

[0034] The plant viral disease targeted by the control agent of the present invention is preferably a mosaic disease caused by infection with various mosaic viruses, potato virus X, or the like.

[0035] The plants to which the control agent of the present invention is applied are not particularly limited as long as they are infected by the above-mentioned pathogens, and examples thereof include solanaceae plants (tobacco, tomato, eggplant, potato, bell pepper, chili pepper, petunia, etc.), cucurbitaceae plants (cucumber, gourd, pumpkin, melon, watermelon, etc.), grasses (rice, barley, wheat, corn, sugarcane, sorghum, sorghum, turfgrass, etc.), cruciferous plants (Chinese cabbage, cabbage, radish, bok choy, rape, etc.), legumes (soybean, , peanuts, peas, kidney beans, broad beans, etc.), Rosaceae plants (strawberries, apples, pears, peaches, plums, roses, cherry blossoms, etc.), Convolvulaceae plants (sweet potatoes, etc.), Liliaceae plants (leeks, onions, lilies, tulips, etc.), Asteraceae plants (lettuce, chrysanthemums, gerberas, etc.), Vitaceae plants (grapes, etc.), Caryophyllaceae plants (carnations, etc.), Orchidaceae plants (cattleyas, cymbidiums, etc.), Gentianaceae plants (lisianthus, etc.), and Plumaceae plants (static, etc.).

[0036] In this way, the control agent of the present invention can be widely applied to plants of the family Solanaceae, Cucurbitaceae, Gramineae, Cruciferae, Legumes, Rosaceae, Convolvulaceae, Liliaceae, Asteraceae, Vitaceae, Caryophyllaceae, Orchidaceae, Gentianaceae, Plumageae, etc. For the relationship between plant viruses and host plants, see the Japan Plant Disease Name Database (Agricultural Biological Resources Genebank).

[0037] The method of applying the control agent of the present invention to plants is not particularly limited, and examples thereof include spraying, coating, immersion, etc. In addition, it is also possible to add the agent to the soil if the target plant is cultivated in soil, or to the hydroponic solution if the target plant is cultivated hydroponically. In the case of plant tissue culture, it is also possible to add the agent to the medium. Since a very high control effect is observed in the area where the control agent of the present invention is applied, the application method is preferably application to the whole plant body or leaves by spraying or coating, or immersion in seeds, bulbs, etc. The control agent of the present invention is advantageous in that it can also show a control effect against plant diseases in the surrounding area of ​​the applied area.

[0038] The application time of the control agent of the present invention to plants is not particularly limited, but preventive control is the 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 control agent is applied.

[0039] The concentration of each active ingredient at the time of application is not particularly limited as long as it is an amount that has a control effect against plant viral diseases, and can be appropriately adjusted by a person skilled in the art, taking into consideration chemical damage to plants, etc. For example, in the case of glycine, the concentration is preferably 0.1 to 50 mM, more preferably 0.5 to 10 mM, even more preferably 1 to 10 mM, and more preferably 2 to 10 mM.

[0040] In the case of a metal or a compound containing the same, the concentration is preferably 0.1 to 50 mM, more preferably 0.5 to 10 mM, further preferably 1 to 10 mM, and more preferably 1 to 5 mM. The molar ratio of glycine to the metal (glycine:metal) is preferably 2:1 to 50:1, and more preferably 2:1 to 10:1.

[0041] In the case of a chelate of glycine and a metal, the concentration is preferably 0.1 to 50 mM. More specifically, in the case of zinc glycine, the concentration is more preferably 0.1 to 40 mM, even more preferably 0.5 to 10 mM, and even more preferably 1 to 10 mM. In the case of copper glycine or iron glycine, the concentration is preferably 0.1 to 10 mM, even more preferably 0.5 to 10 mM, and even more preferably 1 to 10 mM.

[0042] In the case of proanthocyanidins, the amount is preferably 10 to 5000 ppm, more preferably 100 to 1000 ppm, and further preferably 200 to 500 ppm. In the control agent of the present invention, when used in combination with proanthocyanidins, the amount of glycine is preferably 0.1 to 50 mM, more preferably 0.5 to 10 mM, further preferably 1 to 10 mM, and further preferably 2 to 10 mM. EXAMPLES

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0044] Example 1: Control effect of glycine or its zinc chelate against ToMV The plant virus disease control effect of glycine or its zinc chelate was evaluated using a Tomato Mosaic Virus (ToMV)-Nippon Beetle evaluation system. That is, first, a mixture of glycine at a final concentration of 2 mM, zinc glycine at a final concentration of 1 mM, or zinc sulfate at a final concentration of 1 mM and glycine at a final concentration of 2 mM, to which Mylino (a polyalkylene glycol alkyl ether-containing spreading agent manufactured by Nippon Nohyaku Co., Ltd., diluted with water (DDW) for use) at a final concentration of 0.01% was added, was prepared as a test drug. In addition, zinc gluconate (see Patent Document 5), which has been confirmed to have a control effect against ToMV, was adjusted to a final concentration of 1 mM with Mylino at a final concentration of 0.01%, and was used as a control.

[0045] Each of the drugs thus prepared was sprayed onto the stems and leaves of entire Nicotiana benthamiana plants in which three true leaves had developed but the third leaf was still small, and the plants were left standing at 24°C under light for 16 hours. Three days later, the mature third leaf was inoculated with ToMV virus and left standing at 24°C under light for 16 hours.

[0046] ToMV virus was prepared by transcription synthesis using 2 μg of a plasmid (pTLBN.G3, see Kubota K. et al., J Virol. 2003 Oct;77(20):11016-26) encoding ToMV-GFP (a virus with green fluorescent protein GFP added) as a template, and an in vitro RNA transcription synthesis kit (product name: AmpliCap-Max T7 High Yield Message Maker Kits, CellScript). The RNA transcript was then diluted 30-fold, and 10 μl of the solution was applied to two locations of the third leaf of Nicotiana benthamiana using carborundum (600 mesh, Nacalai Tesque, Inc.) to inoculate the virus.

[0047] Three days after inoculation, the number of GFP fluorescent spots corresponding to the sites of ToMV infection and proliferation was counted, and the infection inhibition rate of each drug was assayed. The infection inhibition rate was calculated using the following formula. Infection inhibition rate (control value)% = 100 - {(average number of fluorescent spots on treated plants) / (average number of fluorescent spots on untreated plants)} x 100.

[0048] As a result, as shown in Figure 1A, a virus control effect of glycine was confirmed. Furthermore, it was found that a stronger virus control effect was achieved by using zinc in combination (zinc glycine, zinc sulfate, and glycine). As shown in Patent Document 5, the present inventors have revealed that zinc gluconate has a strong anti-plant virus effect, but it has also been revealed that a combination of glycine and zinc can achieve an even better effect.

[0049] Furthermore, at the 6th day after the virus infection, the virus infection usually spreads to the upper leaves, and the virus-derived GFP fluorescence can be detected in the 4th and subsequent leaves. However, in the Nicotiana benthamiana plants sprayed with the above-mentioned drug, the GFP fluorescence in these upper leaves was suppressed. Thus, the virus control effect of glycine, etc. was observed not only in the leaves directly sprayed with the drug, but also in the upper leaves, so it is considered that glycine, etc. improves the immunity (resistance to pathogens) of the plant.

[0050] Although not shown in the figure, white spots and wilting (phytotoxicity) occurred on Nicotiana benthamiana leaves after treatment with 1 mM zinc sulfate, whereas no phytotoxicity occurred after treatment with any of the test chemicals.

[0051] Furthermore, the plant virus disease control effects of these compounds were evaluated in the same manner as above, except that the test agents were a mixture of glycine at a final concentration of 10 mM, zinc sulfate at a final concentration of 1 mM and glycine at a final concentration of 2 mM, or a mixture of zinc sulfate at a final concentration of 1 mM and glycine at a final concentration of 10 mM, all containing Mylino at a final concentration of 0.01%.

[0052] As a result, as shown in Figure 1B, strong virus control effects were observed at all application concentrations of glycine. Furthermore, in the treatment with all test agents, suppression of virus infection in upper leaves was observed, and as mentioned above, no phytotoxicity occurred.

[0053] Example 2: Control effect of glycine metal chelate against ToMV The plant virus disease control effects of these compounds were evaluated in the same manner as in Example 1 using the ToMV-Nicolas benthamiana evaluation system, except that the test agents were copper sulfate at a final concentration of 1 mM, a mixture of copper sulfate at a final concentration of 1 mM and glycine at a final concentration of 2 mM, a mixture of copper sulfate at a final concentration of 2 mM and glycine at a final concentration of 4 mM, iron (II) sulfate at a final concentration of 1 mM, or a mixture of iron (II) sulfate at a final concentration of 1 mM and glycine at a final concentration of 2 mM, to which Mylino was added at a final concentration of 0.01%.

[0054] As a result, as shown in FIG. 2, the application of a combination of these metal compounds (copper sulfate, iron (II) sulfate) and glycine showed a higher plant virus disease control effect than the application of each metal compound alone. Furthermore, suppression of virus infection in upper leaves was also observed. As mentioned above, although white spots and wilting occurred in Nicotiana benthamiana leaves upon treatment with 1 mM copper sulfate, no such phytotoxicity was observed when copper sulfate or iron (II) sulfate was used in combination with glycine, as in the case of the combination with zinc sulfate shown in Example 1.

[0055] (Example 3) Control effect of ToMV by combined use of glycine and proanthocyanidin Except for the fact that the test agent was a proanthocyanidin with a final concentration of 0.33 mg / ml, or a mixture of the proanthocyanidin and glycine with a final concentration of 2 mM, containing Mylino at a final concentration of 0.01%, the plant virus disease control effects of these compounds were evaluated in the same manner as in the method using the ToMV-Nicotabacillus benthamiana evaluation system described in Example 1. The proanthocyanidin used was extracted and purified from Shell Ginger, a plant of the Zingiberaceae family, Alpinia genus (see Patent Document 6).

[0056] As a result, as shown in Figure 3, it was revealed that the application of a combination of these compounds showed a higher control effect against ToMV than the application of glycine or proanthocyanidin alone. Furthermore, the suppression of viral infection in upper leaves was also observed. Furthermore, no phytotoxicity occurred in this mixed treatment. [Industrial Applicability]

[0057] As described above, according to the present invention, it is possible to exhibit an excellent control effect against plant viruses without causing phytotoxicity such as the occurrence of spots and wilting on leaves, and therefore the present invention can make a great contribution to the agricultural field as a pesticide that is both safe and effective.

Claims

1. A plant viral disease control agent containing glycine and a metal or a compound containing the metal, wherein the concentration of the glycine is 1 to 10 mM, and the metal is at least one metal selected from the group consisting of zinc and iron (however, excluding plant viral disease control agents containing sodium nitrophenol or potassium nitrophenol, triacontanol, dodecyldimethylbenzylammonium chloride or dodecyldimethylbenzylammonium bromide, zinc glycine, copper glycine, peregal, and urea, and plant viral disease control agents containing 5-aminolevulinic acid or a derivative thereof or a salt thereof, and glycine iron sulfide).

2. 2. The plant viral disease control agent according to claim 1, wherein the metal and the glycine form a metal chelate, and the metal chelate is at least one metal chelate selected from the group consisting of zinc glycine and iron glycine.

3. The agent for controlling plant viral diseases according to claim 1 or 2, further comprising a compound containing proanthocyanidin.

4. The control agent according to any one of claims 1 to 3, wherein the plant viral disease is a mosaic disease.

5. A method for controlling a plant viral disease, comprising applying the control agent according to any one of claims 1 to 4 to a plant.

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