JP2021028303A - Bacterial wilt disease control agent and bacterial wilt disease prevention method using the same - Google Patents

Abstract

To provide a bacterial wilt disease control agent and prevention method that can be applied regardless of the growth stage of crops without imposing a burden on workers and the agricultural environment, and effectively prevents the outbreak of bacterial wilt disease as well as that can prevent the spread of damage.SOLUTION: Provided is a bacterial wilt disease control agent containing Oobagi extract as an active ingredient.SELECTED DRAWING: Figure 1

Description

The present invention relates to a brown rot of potato control agent, and more specifically, a brown rot of potato control agent having high safety for crops and producers and having an excellent control effect on brown rot of potato and a brown rot of potato using the same. Regarding control methods.

Bacterial wilt is known as a difficult-to-control disease caused by infection of crops with bacterial wilt. Ralstonia solanacearum infects more than 200 species of plants in 50 families of a wide variety of crops such as tomatoes, eggplants, and potatoes, causing industrial damage due to death. For this reason, the importance of controlling bacterial wilt disease in the agricultural field is extremely high. Ralstonia solanacearum usually colonizes the root surface of the host plant and invades the body. Immediately after invasion, it parasitizes the intercellular space of the root, absorbs nutrients from the host plant, and repeats proliferation. As the growth of bacterial wilt disease progresses, it invades the vascular system of the host plant and repeats its growth there as well. Proliferated bacterial wilt causes a large amount of extracellular polysaccharides that are toxic to the plant and have high viscosity, causing destruction of plant cells and clogging of the vascular system. The host plant dies as the symptoms progress. Ralstonia solanacearum has been confirmed all over Japan, and soil is disinfected with chloropicrin to deal with the damage.

However, chloropicrin is highly toxic, leaving concerns about safety for crops and users. Therefore, a highly safe control method is required for the agricultural environment and producers. For example, a method of throwing plant-derived materials such as molasses and bran into the soil and performing soil reduction disinfection is being attempted. .. However, the soil reduction disinfection treatment can be performed only before the crop is cultivated, and even if the onset of bacterial wilt disease is observed during the cultivation of the crop, the treatment cannot be applied to the surrounding strains. It is not possible to prevent the spread of damage caused by blight.

In addition, a method of controlling bacterial wilt disease using methyl gallate, which is a plant-derived polyphenol (Patent Document 1), and treatment with amino acids increase the disease resistance of plants to prevent the onset of bacterial wilt disease. Although a method for suppressing (Patent Document 2) and the like have been proposed, there are cases where a sufficient control effect cannot be obtained.

JP-A-2009-298736 Japanese Unexamined Patent Publication No. 2012-211244

Therefore, there is a need for a method that can be applied regardless of the growth stage of crops without imposing a burden on workers and the agricultural environment, effectively preventing the occurrence of bacterial wilt disease, and preventing the spread of damage. An object of the present invention is to provide a method for controlling such a bacterial wilt disease.

As a result of diligent research in view of the above problems, the present inventor has excellent antibacterial activity and growth inhibitory effect on bacterial wilt disease, and by applying this to soil, bacterial wilt We have found that the onset of the disease can be effectively suppressed, and have completed the present invention.

That is, the present invention is a brown rot of potato control agent containing a Macaranga tanarius extract as an active ingredient.

The present invention is also a method for controlling bacterial wilt disease, which comprises applying the Macaranga tanarius extract to soil.

Since the bacterial blight control agent of the present invention contains a plant extract as an active ingredient, it is highly safe and has a very small load on workers and the agricultural environment. In addition, it has a high antibacterial effect and growth inhibitory effect on bacterial wilt disease, and can be applied regardless of the growth stage of crops. Therefore, it is possible to reduce the risk of developing bacterial wilt disease and prevent the spread of damage. it can.

It is a photograph which shows the inhibition circle formed on the culture medium in the antibacterial activity test against bacterial wilt disease of Experimental Example 1. a: MAFF107624, b: MAFF21266, c: MAFF21270, d: MAFF212171, e: MAFF211543, f: MAFF301859, g: MAFF311644, h: MAFF730103, i: MAFF730131, j: MAFF730139, k: USE1-8. l indicates the installation position of the paper disc. It is a graph which shows the viable cell count of bacterial wilt disease according to the exposure time to the Macaranga tanarius extract in Experimental Example 2. It shows the incidence of bacterial wilt disease according to the number of days from the start of the test in Experimental Example 3.

The bacterial blight control agent of the present invention contains a Macaranga tanarius extract as an active ingredient.

Macaranga tanatius is an evergreen broad-leaved tree (male and female) belonging to the genus Macaranga of the family Spurge. It inhabits Southeast Asia and northern Australia.

Macaranga tanarius is subjected to extraction processing as an extraction raw material in a state of being collected, crushed or crushed in a dried state, or crushed or crushed after collection. The site to be used is not particularly limited, but the leaf part is preferably used from the viewpoint of antibacterial activity against bacterial wilt. The crushed raw material may have any shape. The raw material can be crushed using a cutter such as scissors, a cutting machine, a crusher, or the like. As the extraction solvent, a polar solvent is preferable from the viewpoint of antibacterial activity against bacterial wilt, and specifically, a lower alcohol having 1 to 4 carbon atoms such as water, methanol, ethanol, butanol, and isopropanol, or a mixed solution thereof, acetone. Examples thereof include ketones such as, and nitriles such as acetonitrile, and water is particularly preferable. The extraction conditions are not particularly limited, but when water is used as the extraction solvent, the temperature is preferably 5 to 100 ° C., more preferably 80 ° C. or higher, from the viewpoint of antibacterial activity against bacterial wilt. The amount of water used at the time of extraction is preferably 1 to 20 times, more preferably 5 to 10 times, the mass ratio of Macaranga tanarius. The extraction time may be, for example, about 10 to 60 minutes.

The extract obtained by the extraction treatment can be used as it is as a bacterial wilt control agent as an extract, but if necessary, it may be further concentrated, dried or the like according to a conventional method. For example, a solid product obtained by drying the extract obtained by hot water extraction can be used as an active ingredient. These are diluted or dissolved with a liquid or solid carrier such as water or lower alcohol, and other additives are added as necessary to make a solid preparation such as powder, granule or wettable powder, or a liquid such as liquid or emulsion. It can be formulated as a preparation. In the brown rot of potato control agent of the present invention, the content of the Macaranga tanarius extract as an active ingredient is not particularly limited, but is preferably 1 to 100% by mass, more preferably 3% by mass or more in terms of solid content. The method for producing the brown rot of potato control agent of the present invention is not particularly limited, and it can be produced according to a known method.

The bacterial wilt control agent of the present invention has excellent antibacterial activity against bacterial wilt. In the present invention, the bacterial wilt disease includes Ralstonia solanacearum as well as Ralstonia syzygii . The bacterial wilt is not limited to race, physiological type, genotype, etc., and for example, Ralstonia solanacearum is MAFF107624, MAFF21266, MAFF21270, MAFF211543, MAFF301859, MAFF311644, MAFF730103, MAFF730131, MAFF730139, Ralstonia syzygii (Obtained from Agricultural Biological Resources Genebank), etc.), and show excellent antibacterial activity against these strains. In addition, the applicant also exhibits excellent antibacterial activity against the strain USE1-8 of a microorganism belonging to the genus Ralstonia isolated from turmeric suffering from bacterial wilt in Okinawa Prefecture. All of these bacterial wilts are pathogenic and have been isolated from tomatoes, potatoes and turmeric.

In the present invention, the bacterial wilt disease to be controlled means a disease of a plant caused by infection with a bacterial wilt disease, and includes bacterial wilt disease, wilt disease and the like. The target plant is not particularly limited as long as it is a plant infected with bacterial wilt, for example, Solanaceae such as eggplant, potato, tomato, and pepper, and ginger family such as ginger, myoga, curcuma, and ginger. Plants such as Udo, Nigauri, Egoma, Strawberry, Banana, Tobacco, Kiku, Geranium, African ginger (Impachens), and Hyakunichisou can be mentioned.

The brown rot of potato can be controlled by applying the brown rot of potato control agent of the present invention containing the Macaranga tanarius extract obtained as described above to soil and plants such as agricultural land. Agricultural land includes, but is not limited to, agricultural land for cultivating tomatoes, potatoes, eggplants, and the like, and may be any soil in which bacterial wilt disease is present or will be present.

When applied to soil such as agricultural land, the bacterial wilt control agent of the present invention can be applied as it is or diluted appropriately and sprayed, sprayed, irrigated or the like on the soil. It may be mixed with pesticides or fertilizers and sprayed. For example, when the solid preparation is applied as it is, a method such as spraying the solid preparation around the roots of the plant or plow into the soil around the roots can be adopted. The application rate of the bacterial wilt disease control agent of the present invention is not particularly limited as long as it is an amount that sufficiently controls bacterial wilt disease inhabiting the soil. For example, 0.1 to 10 g per 1 L of soil. About (solid content conversion), preferably about 2 to 4 g (solid content conversion) may be applied. Since the Macaranga tanarius extract, which is the active ingredient of the brown rot of potato control agent of the present invention, is an extract of a substance existing in nature, it causes harmful effects such as killing agricultural products or killing organisms not to be controlled. The onset of bacterial wilt can be effectively reduced while keeping it to a minimum.

On the other hand, as a method applied to plants, the roots of plants are immersed in a treatment solution containing the bacterial wilt control agent of the present invention, and the treatment solution is sprayed, sprayed, irrigated, etc. on the roots of plants to make blue. A method of contacting a plant with a blight control agent can be mentioned. As the treatment liquid, the liquid preparation which is the bacterial blight control agent of the present invention can be used as it is, or when necessary, diluted with water or the like as appropriate, or a solid preparation dissolved in water or the like is used. You may. The concentration of the Macaranga tanarius extract in the treatment liquid is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more in terms of solid content, for example. The treatment time with the bacterial blight control agent of the present invention can be appropriately set, but for example, the immersion time in the case of the immersion treatment is usually about 1 minute to 48 hours, preferably about 5 minutes to 24 hours.

Hereinafter, the present invention will be set up in detail with reference to examples and the like, but the present invention is not limited thereto.

Production Example 1: Preparation of Macaranga tanarius extract The collected Macaranga tanarius leaves were placed in a dryer at 50 ° C. and dried overnight (collection location: Okinawa Prefecture, Nishihara Town, Ikeda area). This was crushed to about 2 mm by a food processor. 50 g of dried crushed Macaranga tanarius was weighed and packed in a tea strainer pack made of non-woven fabric. 500 ml of water and a dried product were placed in a 1 L beaker, covered with aluminum foil, and heated on an iron plate using a gas stove. The beaker was removed from the iron plate after 10 minutes had passed since the boiling state was continued for 10 minutes from the time when boiling began. The removed beaker was placed at room temperature (20 ° C. to 25 ° C.) and radiated heat until the temperature reached about room temperature. The time required at this time was about 1 to 2 hours. A tea strainer pack containing a dried product was taken out from the extract cooled to room temperature and pressed to prepare a Macaranga tanarius extract. The solid content of the obtained Macaranga tanarius extract was 3% by mass.

Example 1: Antibacterial activity of Macaranga tanarius extract against bacterial wilt disease 11 strains of bacterial wilt disease (MAFF107624, MAFF21266, MAFF21270, MAFF211211, MAFF211543, MAFF301859, MAFF311644, MAFF730103, MAFF730131, MAFF730139 (above, obtained from Agricultural Bioresource Gene Bank) ), USE1-8 (applicant isolated from bacterial wilt disease turmeric in Okinawa prefecture)) was subjected to antibacterial activity experiment of Macaranga tanarius extract. These strains stored as glycerol stocks were inoculated on CPG agar medium (bactopeptone: 10 g, D-glucose: 5 g, casamino acid: 1 g, agarose: 17 g, water: 1 L) and placed in an incubator at 30 ° C. Pre-culture was performed for 1 day. The pre-cultured bacteria were scraped from the agar medium using a loop loop and suspended in a CPG liquid medium (bactopeptone: 10 g, D-glucose: 5 g, casamino acid: 1 g, water: 1 L). The liquid medium was cultured overnight in a constant temperature shaker at 28 ° C. and 180 rpm to prepare a bacterial solution. The OD660 of the prepared bacterial solution was 0.8 to 1.2.

Using the Macaranga tanarius extract prepared in Production Example 1 as a stock solution, a 10-fold diluted solution and a 100-fold diluted solution were prepared. A paper disc (Φ6 mm) was immersed in these Macaranga tanarius solutions for 5 minutes. The soaked paper disc was pulled up and drained and placed in a dry Eppendorf tube. Next, top agar (bact peptone: 10 g, D-glucose: 5 g, casamino acid: 1 g, agarose: 5 g, water: 1 L) was autoclaved at 121 ° C. for 5 minutes to thaw and kept warm at 60 ° C. 250 μL of the bacterial solution liquid-cultured above was added to this top agar and poured into a new CPG agar medium. When the poured top agar cools and hardens, four points on the agar medium are soaked in the undiluted Oobagi extract, 10-fold diluted solution, 100-fold diluted solution, or water only in an Eppendorf tube. Each of them was taken out and placed on an agar medium so that the paper discs did not overlap as shown in FIG. 1 (l). The agar medium on which all the paper discs were installed was closed, placed in an incubator at 30 ° C., and cultured overnight.

On the agar medium after culturing, it becomes cloudy white when the bacteria have grown, but as shown in Fig. 1, the area around the paper disk in which the Macaranga tanarius solution is immersed is transparent because the bacteria have not grown. , Blocking circle formation was confirmed. The formation of blocking circles was observed in all 11 strains, indicating that the Macaranga tanarius extract has a wide range of antibacterial activity against bacterial wilt.

Example 2: Suppression of growth of bacterial wilt disease by Macaranga tanarius extract From the results of Example 1, it was clarified that the Macaranga tanarius extract has antibacterial properties against bacterial wilt disease. It was confirmed how much the viable number of bacterial wilt disease decreased based on the antibacterial property.
On the CPG agar medium, the cultured bacterial wilt disease (MAFF730131) was scraped into 8 mL of the CPG liquid medium, placed in a constant temperature shaker at 28 ° C., and shake-cultured at 180 rpm. Using 100 μL of this bacterial solution, the bacterial density before exposure to the Macaranga tanarius extract was measured, 100 μL of the bacterial solution was added to 900 μL of the Macaranga tanarius extract, and the bacterial density at 30 minutes, 3 hours, and 1 day after exposure was measured. .. As shown in FIG. 2, it was confirmed that when the period of exposure to the Macaranga tanarius extract was prolonged, the growth of bacterial wilt disease was suppressed and the number of viable bacteria in the solution decreased.

Example 3: Suppression of bacterial wilt disease by Macaranga tanarius extract Large tomato (variety: No. 1 in the world) was used as a crop to be evaluated for controllability. Tomato seeds were sown in a 105-hole cell tray filled with mixed soil in which seeding double soil and cell double soil were mixed at a volume ratio of 4: 1. Tomato seedlings cultivated for one and a half months were planted in a PP pot filled with 500 ml of culture soil (purchased from Takayama sand sales in Okinawa Prefecture, composition: Shimajiri red soil, Akadama soil, bark compost, fish flour, vermiculite, etc.), and Example 1 and 2 wilt bacterium cultured similarly CPG liquid medium and (MAFF730131), ingestion of bacteria liquid so that the density of ¹⁰ 5 CFU / g soil. Then, 50 ml of the Macaranga tanarius extract prepared in Production Example 1 was irrigated, and the pathogenicity was recorded by observing with time to evaluate the control effect. The pathogenicity was determined according to the "Microbial Gene Resource Utilization Manual (12) Ralstonia solanacearum " (National Institute of Agrobiological Sciences), and if the first leaf partially withered, it was judged to be pathogenic. As shown in FIG. 3, it was confirmed that the Macaranga tanarius extract suppresses the onset of bacterial wilt disease and has controllability.

Since the bacterial wilt control agent of the present invention is extracted from Macaranga tanarius, which is a broad-leaved tree, it effectively suppresses the onset of bacterial wilt disease without damaging the organisms living in the surrounding environment of agricultural products and agricultural land. be able to. In this way, it is useful in the agricultural field because it is possible to increase the productivity of agricultural products such as tomatoes, eggplants, and potatoes while maintaining the safety of agricultural products and users.

Claims (6)

A brown rot of potato control agent containing Macaranga tanarius extract as an active ingredient. The bacterial wilt control agent according to claim 1, wherein the Macaranga tanarius extract is an extract using a solvent containing water. A method for controlling bacterial wilt, which comprises applying Macaranga tanarius extract to soil. The method for controlling bacterial wilt according to claim 3, wherein the method of applying the Macaranga tanarius extract to soil is a method of spraying, spraying or irrigating the soil with the Macaranga tanarius extract. A method for controlling bacterial wilt, which comprises applying Macaranga tanarius extract to a plant. The method for controlling bacterial wilt according to claim 5, wherein the method for applying the Macaranga tanarius extract to a plant is a method for immersing the roots of the plant in a treatment liquid containing the Macaranga tanarius extract.