Composition for controlling fungi in agricultural crops or plants and method for controlling fungi

Abstract

To provide an inorganic compound-based agricultural crop or plant filamentous fungus control agent and a control method thereof which can be sprayed in liquid form. The present invention relates to a compound having a solubility of 10 g / 100 gH2O in water and a compound having a solubility of 10 g / 100 gH2O in water. 2 A composition for controlling filamentous fungi in agricultural crops or plants, comprising an aqueous suspension containing an iodine-based metal salt selected from a metal iodate having an acid value of less than O and a metal periodate.

Description

[Technical field]

[0001] The present invention relates to a composition and a method for controlling fungi in agricultural crops or plants. [Background technology]

[0002] Infectious diseases of agricultural crops and plants, such as sweet potato base rot and powdery mildew, are caused by filamentous fungi. In particular, sweet potato base rot has been spreading since 2018, and there are no effective means of control, so the development of new means of control is desired. Various fungicides are used to control these diseases, but the highly effective synthetic organic pesticides are highly toxic and pose issues such as safety during spraying, reduced soil activity in fields, and safety as food ingredients.

[0003] Iodine and iodic acid are known to have disinfecting effects against viruses, molds (filamentous fungi), and bacteria, but have a problem in that they are highly soluble in water and dissolve in water, reducing the disinfecting effect. In response to this, a technology has been reported in which iodic acid salts are supported on inorganic or organic materials such as fibers, fabrics, clothing, paper, synthetic resins, plastics, and building materials (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6644325 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inorganic or organic materials carrying the iodate salt cannot be used for disinfection purposes by spraying the liquid on agricultural crops or fields. Therefore, an object of the present invention is to provide an inorganic compound-based agricultural crop or plant fungus control agent and a control method which can be sprayed in liquid form. [Means for solving the problem]

[0006] Therefore, the present inventors have prepared a suspension containing iodate or periodate metal salts having low solubility in water in addition to iodate or periodate, and when the suspension is sprayed on agricultural crops or fields, the insoluble iodate or periodate metal salts cover the stems and leaves of agricultural crops and the surface of the field. In addition, since natural metal elements and metal ions decomposed and dissolved from fertilizers and disinfecting materials are present in the soil, the iodate or periodate that enters the soil reacts chemically with the metal elements and metal ions in the soil to gradually become insoluble iodate or periodate metal salts. Thus, the present inventors have found that the suspension can exert a long-term disinfecting effect from the surface of agricultural crops, plants, and fields to the soil by simply spraying the suspension on agricultural crops, plants, and fields. Thus, the present invention has been completed.

[0007] That is, the present invention provides the following inventions [1] to [8]. [1] A composition for controlling fungi in agricultural crops or plants, comprising an aqueous suspension containing iodic acid or periodic acid and an iodine-containing metal salt selected from a metal iodate and a metal periodate having a solubility in water of less than 10 g / 100 g H2O. [2] The control agent composition according to [1], wherein the iodine-based metal salt is an iodine-based metal salt selected from metal iodates and metal periodates having a solubility in water of less than 1 g / 100 gH2O. [3] The control agent composition according to [1] or [2], wherein the iodine-based metal salt is one or more selected from calcium iodate, iron(III) iodate, copper(II) iodate, potassium periodate, potassium iodate, sodium iodate, and magnesium iodate. [4] The control agent composition according to any one of [1] to [3], wherein the iodine metal salt is one or more selected from calcium iodate, iron(III) iodate, copper(II) iodate, and potassium periodate. [5] The control composition according to any one of [1] to [4], wherein the fungal infection disease is an infection disease selected from sweet potato base rot, powdery mildew, black spot, brown spot, downy mildew, gray mold, white root rot, purple root rot, sooty spot, anthracnose and blast. [6] The control agent composition according to any one of [1] to [5], wherein the fungal infection disease is sweet potato root rot. [7] A method for controlling a filamentous fungal infection disease in agricultural crops or plants, comprising a step of applying the control agent composition according to any one of [1] to [6] to filamentous fungi in agricultural crops or plants. [8] The control method according to [7], wherein the application comprises spraying or coating the control agent composition onto stems, leaves, seed potatoes, seeds, or a field of a target crop or plant. Effect of the Invention

[0008] When the fungal control agent of the present invention is sprayed on agricultural crops or fields, the insoluble metal iodate or metal periodate covers the stems and leaves of agricultural crops and the surface of the field. Since natural metal elements and metal ions decomposed and dissolved from fertilizers and disinfectants are present in the soil, iodic acid or periodic acid that enters the soil reacts chemically with the metal elements and metal ions in the soil to gradually become insoluble metal iodate or metal periodate. Thus, the fungal control agent of the present invention exerts a long-term fungal disinfecting effect from the surface of agricultural crops, plants, and fields above ground to the soil. The filamentous fungus control agent of the present invention is particularly effective as an agent for controlling sweet potato root rot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Terms used in this specification are used in the same manner as commonly used in the art unless otherwise specified.

[0010] In this specification, a filamentous fungus is a fungus that is composed of tubular cells called hyphae and lives in the air, water, and soil. In this specification, the filamentous fungus is intended to infect agricultural crops and plants and cause diseases. Examples of specific target plants and diseases include sweet potato root rot on sweet potatoes; powdery mildew on strawberries, apples, peaches, pears, melons, pumpkins, roses, etc.; black spot on cucumbers, apples, peaches, pears, grapes, plums, etc.; brown spot on apples, grapes, sugar beets, etc.; downy mildew on grapes, cucumbers, Chinese cabbage, spinach, lettuce, radishes, etc.; gray mold on fruits in general, such as strawberries, lettuce, tomatoes, cyclamen, etc.; white root rot and purple root rot on fruits in general, such as asparagus; sooty spot on fruits in general; anthracnose on strawberries, apples, cucumbers, etc.; and blast on rice.

[0011] In this specification, control refers to preventing or suppressing the occurrence of the disease. As used herein, application refers to spraying, coating, etc. of the control agent of the present invention onto the stems, leaves, seed potatoes, seeds, fields, etc. of target crops or plants. For example, in the case of sweet potatoes, examples of this include treatment of seed potatoes and spraying onto stems, leaves, and fields.

[0012] One aspect of the present invention is a composition for controlling filamentous fungi in agricultural crops or plants, comprising an aqueous suspension containing iodic acid or periodic acid and an iodine-based metal salt selected from a metal iodate and a metal periodate having a solubility in water of less than 10 g / 100 g H2O. Another aspect of the present invention is a method for controlling a filamentous fungal infection disease in agricultural crops or plants, comprising a step of applying the control composition of the present invention to a filamentous fungus in the agricultural crops or plants.

[0013] The aqueous suspension used in the present invention contains iodic acid or periodic acid, and an iodine-based metal salt selected from metal iodates and metal periodates having a solubility in water of less than 10 g / 100 gH2O. That is, iodic acid or periodic acid, and an iodine-based metal salt selected from metal iodates and metal periodates having a solubility in water of less than 10 g / 100 gH2O are dissolved in water, and may further contain metal iodates or metal periodates that are not dissolved in water, and other insoluble components.

[0014] Both iodic acid and periodic acid are highly soluble in water and are dissolved in water. The content of one or two selected from iodic acid and periodic acid in the aqueous suspension of the present invention is preferably 0.002% by mass or more and 50% by mass or less, more preferably 0.005% by mass or more and 30% by mass or less, and even more preferably 0.01% by mass or more and 20% by mass or less, from the viewpoint of rapid action of disinfecting filamentous fungi.

[0015] The iodine-based metal salt used in the present invention may be at least one selected from metal iodates and metal periodates having a water solubility of less than 10 g / 100 gH2O, preferably at least one selected from metal iodates and metal periodates having a water solubility of less than 5 g / 100 gH2O, more preferably at least one selected from metal iodates and metal periodates having a water solubility of less than 1 g / 100 gH2O, and even more preferably at least one selected from metal iodates and metal periodates having a water solubility of less than 0.5 g / 100 gH2O. Examples of such iodine-based metal salts include one or more selected from magnesium iodate, sodium iodate, potassium iodate, calcium iodate, iron (III) iodate, copper (II) iodate, and potassium periodate. Among these, one or more selected from calcium iodate, iron (III) iodate, copper (II) iodate, and potassium periodate are more preferred, and calcium iodate is even more preferred from the viewpoint of obtaining a long-term disinfection effect and reducing the burden on the environment. Note that iodine-based metal salts have a low solubility in an aqueous solution in which iodic acid or periodic acid or other iodine-based metal salts are dissolved, compared to their solubility in water. Therefore, in the aqueous suspension of the present invention, iodine-based metal salts may be present without being dissolved in a content less than their solubility in water.

[0016] From the viewpoint of obtaining a long-term disinfection effect, the content of the iodine-based metal salt in the aqueous suspension is preferably 0.0001% by mass or more and 50% by mass or less, more preferably 0.001% by mass or more and 10% by mass or less, and even more preferably 0.002% by mass or more and 5% by mass or less.

[0017] The pH of the aqueous suspension is preferably 7 or less, more preferably 2 to 6.5, even more preferably 2 to 6, and even more preferably 2 to 5, from the viewpoint of obtaining an excellent filamentous fungal control effect.

[0018] The aqueous suspension may contain, in addition to the iodic acid or periodic acid and the iodine-based metal salt, the iodine-based metal salt and other insoluble components that are not dissolved in water. Here, examples of other insoluble components include raw materials for producing the metal iodate or metal periodate and metal compounds derived from the raw materials.Specific examples include calcium compounds, magnesium compounds, alkali metal compounds, iron compounds, copper compounds, etc.Among these, naturally derived components that do not impose a burden on the environment when sprayed on foliage or soil as a fungus control agent are preferred, and calcium silicate, silica, calcium phosphate, calcium citrate, potassium chloride, etc. are preferred.

[0019] To obtain the aqueous suspension, iodic acid or periodic acid and an iodine-based compound selected from metal iodates and metal periodates having a solubility in water of less than 10 g / 100 gH2O may be suspended in water. Specifically, iodic acid or periodic acid and metal periodates or metal iodates may be suspended in water, preferably, iodic acid or periodic acid and one or more selected from magnesium iodate, sodium iodate, potassium iodate, calcium iodate, iron (III) iodate, copper (II) iodate, and potassium periodate may be suspended in water, more preferably, iodic acid or periodic acid and one or more selected from calcium iodate, iron (III) iodate, copper (II) iodate, and potassium periodate may be suspended in water. Furthermore, an aqueous solution of iodic acid or an aqueous solution of periodic acid may be reacted with a metal compound such as a calcium compound, an iron compound, a copper compound, or a potassium compound to produce calcium iodate, iron(III) iodate, copper(II) iodate, or potassium periodate in the aqueous solution. For example, a specific example of producing a suspension containing iodic acid and calcium iodate is preferably produced by reacting calcium silicate fine particles with an aqueous solution of iodic acid to produce calcium iodate in water. The reaction proceeds simply by stirring at room temperature and pressure. The resulting suspension contains iodic acid, calcium iodate, silica, and calcium silicate. In the aqueous suspension containing iodic acid and calcium iodate obtained by this method, the suspended particles are not easily settled, and crystallization does not proceed during storage, so a stable suspension is obtained. According to this method, silica and calcium silicate fine particles remain in the suspension, and silica is known as a component that strengthens plant stems. Therefore, the aqueous suspension of this embodiment can obtain the fungus disinfecting effect of iodic acid, the fungus disinfecting effect over a long period of time of calcium iodate, and the plant growth effect of silica.

[0020] The average particle size of the water-insoluble component in the aqueous suspension of the present invention is preferably 1 to 500 μm, more preferably 1 to 200 μm, and even more preferably 1 to 100 μm, from the viewpoints of long-term suspension, ease of dispersion, etc. The average particle size in this specification is the volume average particle size.

[0021] The aqueous suspension may contain various other components in addition to the above components, such as silica, insecticidal active components, acaricidal active components, nematicidal active components, fungicidal active components, plant growth regulators, chemical damage reducing components, synergists, repellents, molluscicidal components, insect pheromones, herbicidal active components, and biological control materials.

[0022] Since the aqueous suspension contains the insoluble iodine-based metal salt, when the suspension is sprayed on agricultural crops or fields, the insoluble metal iodate or metal periodate covers the stems and leaves of agricultural crops and the surface of the field. Since natural metal elements and metal ions decomposed and dissolved from fertilizers and disinfecting materials are present in the soil, iodic acid or periodic acid that enters the soil reacts chemically with elements and metal ions in the soil to gradually become insoluble metal iodate or metal periodate. Thus, the suspension exerts a long-term disinfecting effect on agricultural crops, plants, and fields from the surface to the soil of the aboveground agricultural crops, plants, and fields simply by spraying the suspension.

[0023] The target diseases of the filamentous fungus control agent of the present invention are diseases caused by filamentous fungi on agricultural crops or plants, and specifically include sweet potato base rot on sweet potato; powdery mildew on strawberry, apple, peach, pear, melon, pumpkin, rose, etc.; black spot on cucumber, apple, peach, pear, grape, plum, etc.; brown spot on apple, grape, sugar beet, etc.; downy mildew on grape, cucumber, Chinese cabbage, spinach, lettuce, radish, etc.; gray mold on fruits in general, strawberry, lettuce, tomato, cyclamen, etc.; white root rot and purple root rot on fruits in general, asparagus, etc.; sooty spot on fruits in general; anthracnose on strawberry, apple, cucumber, etc.; rice blast on rice, etc. Among these, the control effect against sweet potato base rot is particularly excellent.

[0024] To control fungal diseases in agricultural crops or plants, a step of applying the control composition of the present invention to fungi in agricultural crops or plants is carried out. Specifically, this means spraying or coating the control composition of the present invention on the stems, leaves, seed potatoes, seeds, fields, etc. of the target agricultural crops or plants. For example, in the case of sweet potato, the control composition of the present invention may be applied to seed potatoes, seedlings, stems, leaves, or fields by spraying. In the case of spraying to seedlings, stems, leaves, or fields of sweet potato, the control composition of the present invention may be applied once or multiple times at 1 to 10,000 g per hectare. In the case of seed potatoes of sweet potato, the control composition may be applied at 0.01 to 10,000 ppm. EXAMPLES

[0025] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0026] Manufacturing Example 1 (1) 1 g of calcium silicate microparticles (xonotlite dry powder manufactured by A&A Material Co., Ltd.) and 109 g of a 12 wt % aqueous solution of iodic acid were mixed at 20°C for 1 hour to produce iodine compound suspension A. The liquid suspension contained approximately 1 wt % calcium iodate. In theory, it also contained unreacted calcium silicate microparticles and reacted silica.

[0027] Test Example 1 (Floatability evaluation test of iodine compound suspension) 50 mL of iodine compound suspension A was placed in a 50 mL measuring cylinder. This was placed in a box with a black background and lit from above. The stirring rod was removed from the measuring cylinder and the buoyancy was checked at each elapsed time. A video was taken, and then the buoyancy was compared using still images. First, in the iodine compound suspension A that had been left to stand for 168 days, no lumps such as adhesion to the container or aggregation were observed. To evaluate buoyancy, the suspension was stirred in a measuring cylinder, then left to stand and visually checked for transparency and the state of precipitate. Suspension A was confirmed to still be floating even after 1,190 seconds. In addition, 30 seconds after stirring, about 3 mL of precipitate was formed in suspension A, but the suspension remained stable for the next 1,190 seconds.

[0028] Test Example 2 (Measurement of particle size distribution of iodine compound suspension) The liquid was mixed at high speed with a magnetic stirrer to prepare a suspension. The suspension was filtered to collect the precipitate. The precipitate was dried at 105°C for 24 hours. Since the dried precipitate dissolves in water, the suspension was prepared using ethanol as the dispersion solvent. The particle size distribution of the precipitate dispersed in the suspension was measured using a SALD-2200 (WingSALD II: Version 3.1.1) (Shimadzu Corporation). The particle size distribution of the precipitate from iodine compound suspension A was 34.176 μm (σ=0.276), and the average particle size was small. The particle size distribution was also leaning toward the small side. In the floatability evaluation, it was found that iodine compound suspension A took a long time to settle, which was supported by the fact that the average particle size of iodine compound suspension A was small. Iodine compound suspension A, which has these characteristics, is thought to have an average particle size range of about 20 to 45 μm.

[0029] Test Example 3 (Changes in pH and Oxidation-Reduction Potential (ORP) of Iodine Compound Suspension over Time) The test specimen was thoroughly stirred and 1 mL was dispensed using a micropipette. It was serially diluted 100-fold, 250-fold, and 500-fold with purified water. The pH and ORP were measured. As a result, as shown in Table 1, regardless of the dilution ratio, the pH and ORP did not decrease significantly 60 days and 168 days after preparation. The measurements were performed using a newly purchased tester 60 days and 168 days after preparation.

[0030] [Table 1]

[0031] Test Example 4 (Antibacterial test using Escherichia coli) Iodine compound suspension A was diluted with purified water to three levels, 100 times, 250 times, and 500 times, and provided to the testing institute. 10 mL of the liquid sample was placed in a petri dish, 0.1 mL of bacteria suspension BGLB liquid was added, and the mixture was stirred. After culturing at 35°C for 18 hours, 10-fold serial dilutions were made, and 1 mL of the diluted liquid was mixed with a standard agar medium. After culturing at 35°C for 22 hours, the amount of bacteria was measured. As a result, as shown in Table 2, high antibacterial activity was confirmed at all three dilution levels. 8 CFU / ml.

[0032] [Table 2]

[0033] Test Example 5 (Field test using sweet potato root rot fungus) (1) Test period Test start date: July 6, 2023 - Test end date: November 15, 2023 The ideal growing season for sweet potatoes is from early April to late September, but because base rot spreads easily in hot and humid environments and rain causes spores to flow out of the infected area and spread, farmers are taking measures to harvest early. (2) Planting sweet potato seedlings using root rot fungus and iodine compound suspension A The study was conducted outdoors in a contaminated field (androsol soil). 1) Sweet potato seedlings are sterilized with sterilized Koganesengan 2) 1 section 5m 2 15 seedlings were planted at 100cm intervals per row (1m x 5m) and 30cm intervals between plants. 3) Five plots were randomly arranged per level, and a total of 75 plants were planted. 4) The test bacteria is a liquid containing a stock strain of sweet potato root rot bacteria adjusted to a specified concentration. 5) Spread a specified amount of test bacteria in a 20 cm width on the center of the soil surface of a previously cultivated furrow. 6) For the pesticide prototype, use iodine compound suspension A diluted 500 times. 7) The amount of spray is 1m 2 per liter 8) Spray a specified amount of the pesticide prototype in a 20 cm width on the center of the soil surface of the ridge where the test bacteria was sprayed. 9) Five randomly placed plots were left untreated without any pesticide spraying. After the test started, the seedlings were regularly observed by a public institution. A damage index was calculated from the number of plants infected with root rot and from plants that had died due to causes other than root rot, and the overall evaluation result was shown as a control value. In addition, the practicality of the product was judged based on the control value. The control value is an index used to evaluate the effectiveness of a pesticide when testing it against pests and diseases. It is a numerical value that indicates the degree to which damage was suppressed compared to the damage in an untreated area, and is calculated using the following formula. Control value = 100 - (damage index of treated area / damage index of untreated area) x 100 (3) Test results The first outbreak of root rot was confirmed on August 23, 47 days after planting. The disease progressed slowly thereafter, and the field test showed little disease in the untreated area 131 days after planting. The control value of a 500-fold diluted iodine compound suspension A was 20.8 on September 22nd, 29.8 on October 11th, 29.8 on October 24th, and 33.9 on November 15th. No dead plants were found, and although the control value was low, it was judged to be practical.

Claims

1. A composition for controlling filamentous fungi in agricultural crops or plants, comprising iodic acid or periodic acid, and one or more iodine-based metal salts selected from calcium iodate, iron(III) iodate, copper(II) iodate, and potassium periodate, and an aqueous suspension containing the metal iodate and the metal periodate that are not dissolved in water.

2. 2. The control composition according to claim 1, wherein the fungal infection disease is an infection disease selected from sweet potato base rot, powdery mildew, black spot, brown spot, downy mildew, gray mold, white root rot, purple root rot, sooty spot, anthracnose and rice blast.

3. The control composition according to claim 1 , wherein the fungal infection disease is sweet potato root rot.

4. A method for controlling a filamentous fungal infection disease of agricultural crops or plants, comprising a step of applying the control agent composition according to any one of claims 1 to 3 to filamentous fungi of agricultural crops or plants.

5. The control method according to claim 4, wherein the application comprises spraying or coating the control agent composition on stems, leaves, seed potatoes, seeds or fields of the target crop or plant.

Images