Composition for controlling filamentous fungal infectious diseases of crops or plants and method for controlling the same

Abstract

To provide an inorganic controlling agent and a controlling method that exhibit controlling activity against filamentous fungal infectious diseases of crops or plants for an extended period through spraying onto crops or soil.SOLUTION: A composition for controlling filamentous fungal infectious diseases of crops or plants comprises particles having an inorganic iodine compound supported on a silica-based inorganic porous material having a particle size of 1 mm or more and 6 mm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for controlling fungal infection diseases of agricultural crops or plants and a method for controlling the diseases. [Background technology]

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

[0003] Iodine and iodic acid are known to have disinfecting properties against viruses, mold (filamentous fungi), and bacteria. However, their high solubility in water reduces their disinfecting properties when iodine is dissolved in water. To address this issue, an iodine-loaded material (Patent Document 1) has been reported in which iodine is supported on an adsorbent material such as activated carbon or fiber to prevent its release into the air or water, and the material is acidified to prevent the generation of iodate ions when the iodine is loaded. Furthermore, since activated carbon powder disperses in the air or water, a material has also been reported in which iodate salts are formed on the surface of a material such as calcium silicate, providing antibacterial and deodorizing properties (Patent Document 2). However, while hydraulic inorganic materials, such as calcium silicate, react with water and harden at room temperature and pressure, many of them exhibit (weak) alkaline properties. Therefore, after outdoor application, they deteriorate due to acidic soil, ultraviolet light, and climate change, resulting in insufficient durability. Furthermore, it has been difficult to inexpensively produce acidic materials suitable for the formation of iodate salts at room temperature and pressure. Therefore, the present applicant discovered that an antibacterial and disinfecting support in which an inorganic iodine compound is supported on a silica-based inorganic porous material derived from volcanic minerals, characterized in that the antibacterial and disinfecting support has a pH of 2 to 5, an oxidation-reduction potential in an oxidized state, and a bulk density of 0.4 to 1.5, has improved antibacterial activity and good usability, and filed a patent application (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-125560 [Patent Document 2] Patent No. 6644325 [Patent Document 3] Japanese Patent Publication No. 2022-24524 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the tests conducted in Patent Documents 1 to 3 only examined whether or not the compounds directly act on Escherichia coli and viruses, and did not confirm whether or not they exert a long-term fungal infection disease control effect when sprayed on agricultural crops or soil. Therefore, an object of the present invention is to provide an inorganic control agent and a control method which, when applied to agricultural crops or soil, exerts a control effect on agricultural crops and plant fungal infectious diseases for a long period of time. [Means for solving the problem]

[0006] Therefore, the present inventors have found that by obtaining particles in which an inorganic iodine compound is supported on a silica-based inorganic porous body of a certain particle size and spraying the particles on agricultural crops, plants or fields, the inorganic iodine compound acts on the agricultural crops or plants over a long period of time, thereby achieving a control effect against fungal infections of the agricultural crops or plants, and have completed the present invention.

[0007] That is, the present invention provides the following [1] to [9]. [1] A composition for controlling fungal infection diseases of agricultural crops or plants, comprising particles in which an inorganic iodine compound is supported on a silica-based inorganic porous body having a particle diameter of 1 mm or more and 6 mm or less. [2] The control composition according to [1], wherein the inorganic iodine compound is one or more selected from iodine, triiodide, iodic acid, periodic acid, and salts thereof. [3] The control composition according to [1] or [2], wherein the inorganic iodine compound is one or more compounds selected from iodic acid and iodate salts. [4] The pest control composition according to any one of [1] to [3], wherein the particles carrying the inorganic iodine compound have a pH of 3 to 7, a redox potential of +200 mV to +600 mV, and a bulk density of 0.35 to 2.2. [5] The control agent composition according to any one of [1] to [4], wherein the particle diameter of the silica-based inorganic porous material is 1 mm or more and 3 mm or less. [6] The control agent composition according to any one of [1] to [5], 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. [7] The control agent composition according to any one of [1] to [6], wherein the fungal infection disease is sweet potato root rot. [8] A method for controlling a fungal infection disease in agricultural crops or plants, comprising the step of applying the control agent composition according to any one of [1] to [7] to fungi in agricultural crops or plants. [9] The control method according to [8], wherein the application comprises spraying or coating the control agent composition on the stems, leaves, seed potatoes, seeds, or fields of the target crops or plants. [Effects of the Invention]

[0008] When the fungal infection disease control agent of the present invention is sprayed on agricultural crops or fields, the inorganic iodine compound salt carried on the particles is gradually released and acts on the stems and leaves of agricultural crops and the surface of the field over a long period of time, and simply by spraying the agent on agricultural crops, plants, or fields, it exerts a long-term fungal disinfecting effect from the surface of aboveground agricultural crops, plants, and fields to the soil. The agent for controlling filamentous fungal infections of the present invention is particularly effective as an agent for controlling sweet potato root rot. DETAILED DESCRIPTION OF THE INVENTION

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

[0010] In this specification, filamentous fungi are fungi that are composed of tubular cells called hyphae and live in the air, water, and soil. In this specification, the term "filamentous fungi" refers to filamentous fungi that 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 rice 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 or coating 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 potato, examples include treatment of seed potatoes and spraying onto stems, leaves, and fields.

[0012] One aspect of the present invention is a composition for controlling fungal infection diseases of agricultural crops or plants, which contains particles in which an inorganic iodine compound is supported on a silica-based inorganic porous body having a particle diameter of 1 mm or more and 6 mm or less. 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 agent composition of the present invention to filamentous fungi in agricultural crops or plants.

[0013] The composition for controlling fungal infection diseases of agricultural crops or plants of the present invention contains particles in which an inorganic iodine compound is supported on a silica-based inorganic porous body having a particle diameter of 1 mm or more and 6 mm or less. The particle size of the silica-based inorganic porous material used is preferably 1 mm or more and 6 mm or less, more preferably 1 mm or more and 4 mm or less, and even more preferably 1 mm or more and 3 mm or less, from the viewpoints of applicability and long-term sustained release of the active ingredient. Furthermore, from the viewpoint of environmental load, the silica-based inorganic porous material is preferably derived from a natural product, and examples thereof include those selected from pumice, crushed pumice, molded bodies of pumice or crushed pumice, and filled bodies of pumice or crushed pumice.

[0014] Pumice is a foamed, porous, and mainly whitish pyroclastic rock, also known as pumice. Minerals contained in pumice include pumice, dacite, rhyolite, plagioclase, hypersthene, augite, amphibole, quartz, cristobalite, apatite, felsic rock, basalt, andesite, biotite, orthopyroxene, clinopyroxene, obsidian, magnetite, volcanic glass, feldspar, scoria, tuff, pumice-bearing tuff, granite, andesite, and dacite. Examples include rock, granodiorite, pumice volcanic gravel tuff, pumice, halloysite, allophane, imogolite, gypsite, volcanic breccia, tuff breccia, tuff agglomerate, slag tuff, gabbro, diorite, porphyry, potassium feldspar, zeolite, axite, fluorite, porphyrite, welded tuff, reticulite, acid clay, silica, sinter, serpentine, etc. Specific examples of such pumice include Kanuma soil, Imaichi soil, Miya soil, foxtail soil (foxtail sand), Hyuga soil, Ezo sand, Fuji sand, Akadama soil, Kiryu sand, Kirishima Oike mulberry, Sakurajima Taisho mulberry, mulberry, kora, ash stone, balsamic, quail, gravel, Akahoya, Kuroboku, and Kuroniga.

[0015] Among these silica-based inorganic porous materials, silica-based inorganic porous materials having a pH of 4 to 8, an oxidation-reduction potential of +100 mV to +500 mV, and a bulk density of 0.3 to 2 are preferred in terms of obtaining excellent effects for controlling fungal infections in agricultural crops or plants. The pH is preferably 4 to 8, more preferably 4 to 7, and even more preferably 4 to 6. Here, the pH can be measured by mixing 10 g of the silica-based inorganic porous material with 50 ml of water at room temperature, shaking the mixture for 60 minutes, and then using the resulting solution with a pH meter.

[0016] The redox potential of the silica-based inorganic porous material used must be on the oxidizing side in order to bring the redox potential of the inorganic iodine compound-supported particles (hereinafter also simply referred to as supported particles) into an oxidizing state and to obtain excellent agricultural crop or plant fungal infection control effects due to the inorganic iodine compound supported in the particles.From the viewpoint of obtaining excellent agricultural crop or plant fungal infection control effects, the redox potential is preferably +100 mV to +500 mV, more preferably +200 mV to +500 mV, and even more preferably +300 mV to +500 mV. Here, the oxidation-reduction potential can be measured by mixing 10 g of silica-based inorganic porous material with 50 ml of water at room temperature, shaking for 60 minutes, and using the resulting solution with an oxidation-reduction potentiometer.

[0017] The bulk density of the silica-based inorganic porous material is preferably 0.3 to 2.0, more preferably 0.4 to 1.5, and even more preferably 0.6 to 1.2, from the standpoints of the agricultural crop or plant fungal infection control effect of the supported particles, strength, reduction of equipment wear load required for transporting and mixing raw materials and products, reduction of energy costs required for production and transportation, prevention of dust generation from raw materials, and ease of operation when spraying by hand or power in granular form. Here, the bulk density of the inorganic porous body is the loose bulk density. The loose bulk density of particles can be measured by filling the porous body into a 500 ml measuring cylinder under its own weight without compressing, shaking, or vibrating it, determining the volume, and then dividing the weight of the porous body used for filling by the volume.

[0018] The inorganic iodine compound supported on the silica-based inorganic porous material may be one or more selected from iodine, triiodide, iodic acid, periodic acid, and salts thereof, and more preferably one or more selected from iodic acid and iodate salts. In the support particles of the present invention, these inorganic iodine compounds are preferably present in the form of one or more selected from iodine, triiodide ions, iodate ions and periodate ions.

[0019] The amount of these inorganic iodine compounds supported on the supported particles of the present invention is not particularly limited as long as it is an amount that shows the effect of controlling fungal infections in agricultural crops or plants, but is preferably 0.01 mass% or more, more preferably 0.1 mass% to 10 mass%, and even more preferably 0.2 mass% to 5 mass% of the amount of supported particles.

[0020] The above-mentioned support particles preferably have a pH of 3 to 7, an oxidation-reduction potential of +200 mV to +600 mV, and a bulk density of 0.35 to 2.2, in order to obtain an excellent effect of controlling fungal infections in agricultural crops or plants. The pH is preferably 3 to 7, more preferably 3 to 6, and even more preferably 3 to 5. From the viewpoint of obtaining an excellent effect of controlling fungal infections in agricultural crops or plants, the oxidation-reduction potential is preferably +200 mV to +600 mV, more preferably +300 mV to +600 mV, and even more preferably +400 mV to +600 mV. The bulk density is preferably 0.35 to 2.2, more preferably 0.45 to 1.65, and even more preferably 0.7 to 1.3. Here, the pH, oxidation-reduction potential and bulk density can be measured in the same manner as for the silica-based inorganic porous material.

[0021] The supported particles of the present invention can be produced by supporting an inorganic iodine compound on a silica-based inorganic porous material having a particle diameter of 1 mm to 6 mm. More specifically, the supported particles can be produced by reacting the inorganic iodine compound dissolved or dispersed in a solvent with the silica-based inorganic porous material by mixing, coating, spraying, or impregnation. The inorganic iodine compound to be used may be one or more selected from iodine, triiodide, iodic acid, periodic acid, and salts thereof, and more preferably one or more selected from iodic acid and iodate salts. The solvent is preferably water or a polar solvent, more preferably water. The operations of mixing, coating, spraying, or impregnation are preferably carried out at room temperature (usually 5 to 35°C), and if drying is required, it is preferably carried out at room temperature to about 120°C. The amount of the inorganic iodine compound to be used is determined taking into consideration the amount to be supported.

[0022] Among the supported particles of the present invention obtained as described above, there are those with high hardness and those with low hardness depending on the properties of the silica-based inorganic porous material used as the raw material. In the present invention, the supported particles are sprayed on agricultural crops or a field, and the inorganic iodine compound supported on the particles is gradually released and acts on the stems and leaves of agricultural crops and the surface of the field over a long period of time. In this respect, the hardness in a dry state is preferably 2N or more and 70N or less, more preferably 10N or more and 60N or less, and even more preferably 20N or more and 50N or less. (Method for measuring particle hardness) Using a Kiya-type digital hardness tester KHT40N manufactured by Fujiwara Seisakusho Co., Ltd., measurements were taken of Hyuga soil and Kanuma soil particles in a dry state after drying at 60°C for 24 hours, and in a saturated state. For hardness measurements, one particle of each raw material was randomly selected, and the load value when it was crushed by applying a compressive load was determined. Tests were conducted with n=20. If the particles were soft and the load value of the hardness tester remained at the lower limit of the hardness tester, and the particle deformed to a thickness of less than half of its initial size, it was deemed unmeasurable.

[0023] Since the inorganic iodine compound is loaded onto the obtained supported particles, when the supported particles are sprayed onto agricultural crops or fields, the inorganic iodine compound salt loaded onto the particles is gradually released and acts on the stems and leaves of the crops and the surface of the field over a long period of time. Simply by spraying the particles onto agricultural crops, plants or fields, a long-term fungal disinfecting effect is exerted on the surface of the crops, plants and fields above ground, from the surface to the soil, and fungal infections of the crops or plants can be controlled.

[0024] The target diseases of the filamentous fungal infection control agent of the present invention are diseases of agricultural crops or plants caused by filamentous fungi, specifically, sweet potato base rot on sweet potato; powdery mildew on strawberries, apples, peaches, pears, melons, pumpkins, roses, etc.; black scab 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 rice blast on rice. Of these, the control effect on sweet potato base rot is particularly excellent.

[0025] To control fungal diseases of agricultural crops or plants, the control composition of the present invention is applied to the fungi of the agricultural crops or plants. Specifically, this means spraying or coating the control composition of the present invention onto the stems, leaves, seed potatoes, seeds, fields, etc. of the target agricultural crops or plants. For example, in the case of sweet potato, examples include treatment of seed potatoes and spraying of seedlings, stems, leaves, and fields. In spraying of sweet potato seedlings, stems, leaves, or fields, the control composition of the present invention may be sprayed once or multiple times at a rate of 1 to 10,000 L per hectare. In addition, in treatment of sweet potato seed potatoes, 0.01 to 10,000 ppm may be applied. [Example]

[0026] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0027] Example 1 (Iodate loading on borate) Using 60 g of dry borate earth with particle diameters of 4 mm or less and 20 ml of iodic acid aqueous solution (concentration 3%), the borate earth was stirred in a glass container, and the iodic acid aqueous solution was gradually added dropwise to the borate earth, resulting in uniform loading of the iodic acid aqueous solution without any residue. The resulting loaded particles maintained their granular shape prior to loading.

[0028] Example 2 (Iodate loading on Akadama soil) Using the same method as in Example 1, 40 g of Akadama soil with particle diameters of 6 mm or less was mixed with 20 ml of an aqueous iodic acid solution (concentration: 3%). The mixed Akadama soil became a slightly viscous paste-like mixture with particles. The particles, which had iodic acid salts loaded on the Akadama soil, could be separated into particles and powder by sieving.

[0029] Table 1 shows the pH, oxidation-reduction potential and bulk density of the silica-based inorganic porous materials used in Examples 1 and 2 and the resulting supports.

[0030] [Table 1]

[0031] Example 3 (Antibacterial activity test using Escherichia coli) The supported particles A obtained in Example 1 were subjected to an antibacterial test against Escherichia coli. Antibacterial (E. coli) test method The supported particles A were thoroughly dried at room temperature, and 1 g was placed in a test tube and soaked in an E. coli suspension (10 8 CFU / ml) was added and mixed well. After incubation at 35°C for 18 hours, 5 ml of saline was added and washed out. 1 ml of the washed out liquid was mixed well with standard agar medium and placed in a petri dish. After incubation at 35°C for 22 hours, the bacterial count was measured. As a result, as shown in Table 2, high antibacterial performance was confirmed from 0.05 mass % to 1.0 mass % of the supported bacteria. 8 CFU / ml.

[0032] [Table 2]

[0033] Example 4 (Field test using sweet potato root rot fungus) (1) Exam period Test start date: July 6, 2023 - Test end date: November 15, 2023 The optimum growing season for sweet potatoes is said to be from early April to late September, but because root rot thrives in high temperatures and humidity, and rain causes spores to leak from infected areas and spread, farmers are taking measures to harvest earlier. (2) Planting sweet potato seedlings using root rot fungus and carrier particles A The experiment was conducted outdoors in a contaminated field (andosol soil). 1) Sweet potato seedlings are sterilized in Koganesengan 2) 1 section 5m 2 15 seedlings were planted at a distance of 100cm between rows and 30cm between plants per 1m x 5m. 3) Five plots were randomly placed 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 predetermined amount of test fungus in a 20 cm width on the center of the soil surface of the previously cultivated furrow. 6) The pesticide prototype uses 1.0 wt% and 0.5 wt% supported particles A. 7) The spray volume is 1m 2 1L per 8) Spray a predetermined amount of the pesticide sample in a 20cm 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 pesticides. After the test began, 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 presented as a control value. The practicality of the product was also judged based on the control value. Control value is an index used to evaluate the effectiveness of a pesticide in testing against pests and diseases. It is a numerical value that indicates the degree to which damage was reduced compared to 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 cases of root rot were confirmed on August 23, 47 days after planting. The disease progressed slowly thereafter, and the field test showed little disease in the untreated plots 131 days after planting. The control values ​​of supported particles A at 1.0 mass% and 0.5 mass% loadings were 100.0 and 62.5 on September 22nd, 72.3 and 80.9 on October 11th, 53.2 and 61.7 on October 24th, and 60.7 and 41.1 on November 15th. No dead plants were observed, and the products were judged to be practical in all cases. Supported particles A have the advantage that iodine compounds gradually dissolve into the soil through the voids in the bora soil, causing no phytotoxicity to seedlings and maintaining antibacterial effects for a long period of time. It has been confirmed that the particles are effective in preventing root rot without causing phytotoxicity.

Claims

1. A composition for controlling fungal infection diseases of agricultural crops or plants, comprising particles in which an inorganic iodine compound is supported on a silica-based inorganic porous body having a particle diameter of 1 mm or more and 6 mm or less.

2. 2. The pesticide composition according to claim 1, wherein the inorganic iodine compound is one or more compounds selected from the group consisting of iodine, triiodide, iodic acid, periodic acid, and salts thereof.

3. The pesticide composition according to claim 1, wherein the inorganic iodine compound is one or more compounds selected from the group consisting of iodic acid and iodate salts.

4. 2. The pesticide composition according to claim 1, wherein the particles carrying the inorganic iodine compound have a pH of 3 to 7, an oxidation-reduction potential of +200 mV to +600 mV, and a bulk density of 0.35 to 2.

2.

5. 2. The pesticide composition according to claim 1, wherein the particle diameter of the silica-based inorganic porous material is 1 mm or more and 3 mm or less.

6. 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.

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

8. A method for controlling fungal infections of agricultural crops or plants, comprising the step of applying the control agent composition according to any one of claims 1 to 7 to fungi on the agricultural crops or plants.

9. The control method according to claim 8, wherein the application comprises spraying or coating the control agent composition onto stems, leaves, seed potatoes, seeds, or fields of the target crops or plants.

Images