JP2017095397A - Plant disease control agent, plant disease control agent using microorganism material, plant disease control agent and plant disease control method for suppressing and controlling generation of rice blast disease, major disease of rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plant disease control agent for suppressing and controlling generation of rice blast disease which is a major disease of rice.SOLUTION: There is provided a plant disease control agent containing bacterium liquid made by heat treatment in a temperature range of 65°C to 80°C for 60 minutes or more after culturing Bacillus pumillusTUAT1 strain (NITE BP-1356) and having spore rate of 100% and bacterial concentration of 1.0×10to 9.0×10cfu/g.SELECTED DRAWING: None

Description

  Conventionally, Bacillus bacteria (for example, Bacillus pumilus) have been known to be useful bacteria having characteristics such as plant growth promotion, disease suppression, odor reduction, and proteolytic properties.

  The inventors of the present application have advanced research on Bacillus bacteria, and have improved the root area of applied crops (for example, rice), improved root fixation, increased root weight, and improved nutrient absorption. The biofertilizer which can be produced is proposed (patent documents 1, 2, nonpatent literature 1).

JP 2015-113274 A International Publication WO2015 / 093428

Abstracts of Annual Meeting of the Japanese Society of Soil Microbiology 2013 (2013.06.19 p.77

  The inventors of the present application select a Bacillus pumilus TUAT1 strain (NITE BP-1356) (hereinafter sometimes referred to as “TUAT1 strain”) from Bacillus pumilus, and expand the root area when applied to rice. The effect of promoting nutrient absorption was examined.

  The Bacillus pumillus TUAT1 strain has been deposited internationally at the Patent Microorganism Depositary, and the deposit number is NITE BP-1356.

The inventors of the present application are effective in expanding the root area and promoting nutrient absorption by the Bacillus pumilus TUAT1 strain (NITE BP-1356) described above, particularly in enhancing the root area and applying nutrient absorption when applied to rice. Focusing on Bacillus pumilus, which shows similar trends, researched and cultured Bacillus genus bacteria (Bacillus pumillus TUAT1 strain (NITE BP-1356)), and then heat-treated at 65 ° C to 80 ° C for 60 minutes or more. A biofertilizer having a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g has been completed (Patent Documents 1 and 2).

  In addition, a granular fertilizer made of any one or a combination of diatomaceous earth, zeolite, and silica gel is immersed in the biofertilizer and then dried to a moisture content of 12% to 2%. After adding and mixing the biofertilizer to the fertilizer material consisting of any one or a combination of biofertilizer, diatomaceous earth, zeolite, and silica gel, until the water content becomes 12% to 2% A granular biofertilizer obtained by drying is proposed (Patent Documents 1 and 2).

  On the other hand, the influence on the pathogenic resistance of the Bacillus pumilus TUAT1 strain (NITE BP-1356) described above was unknown.

  This inventor examined the influence of Bacillus pumilus TUAT1 strain (NITE BP-1356) on rice blast and completed the present invention.

  We propose a plant disease control agent and a plant disease control method for suppressing and controlling the occurrence of rice blast, which is an important disease of rice (rice).

Bacillus pumillus TUAT1 strain (NITE BP-1356) is cultured and then heat-treated at a temperature range of 65 ° C. to 80 ° C. for 60 minutes or more with a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^{7 to} 9.0 ×. A plant disease control agent comprising a bacterial solution of 10 ⁷ cfu / g.

  It is possible to provide a plant disease control agent and a plant disease control method for suppressing and controlling the occurrence of rice blast, which is an important disease of rice (rice).

The figure showing the result of the growth investigation at the time of rice planting at the time of examining the suppression of the rice blast disease by the granular plant disease control agent of this invention, and the plant disease control effect in the field of Nihonmatsu-shi, Fukushima Prefecture. The reference photograph showing the state of the seedling at the time of rice planting in the examination shown in FIG. The figure which shows the result of having investigated the suppression of the rice blast disease by the granular plant disease control agent of this invention, and the plant disease control effect in the field of Nihonmatsu-shi, Fukushima Prefecture. The figure which shows the conditions at the time of using the bacterial solution used for the granular plant disease control agent of this invention, and performing the rice blast inoculation test by pot cultivation. The reference photograph showing the growth state of the rice at the time of 4 weeks cultivation in the rice blast inoculation test by the pot cultivation performed on the conditions shown in FIG. The figure which shows the blast disease inoculation condition in the rice blast disease inoculation test by the pot cultivation performed on the conditions of FIG. The figure showing the result of the rice blast inoculation test by the pot cultivation performed on the conditions of FIG. 4, FIG. Rice blast caused by pot cultivation in the case of using the bacterial solution used for the granular plant disease control agent of the present invention and consisting of the material (inoculation holding agent) and the bacterial solution and only the material (inoculation holding agent) Figure showing conditions when inoculation test was conducted The figure showing the result of the test done on the conditions shown in FIG.

The present invention is a spore rate of 100% obtained by culturing Bacillus pumillus TUAT1 strain (NITE BP-1356) and then heat-treating at 65 ° C. to 80 ° C. for 60 minutes or more, and the bacterial concentration is 1.0 × 10 ⁷ to A plant disease control agent comprising 9.0 × 10 ⁷ cfu / g fungal fluid.

  This plant disease control agent is a dry treatment until the moisture content becomes 12% to 2% after immersing a granular material made of any one or a combination of diatomaceous earth, zeolite, and silica gel in the bacterial solution. Can be prepared.

  In addition, the bacterial solution is granulated by adding and mixing to a material composed of any one or a combination of diatomaceous earth, zeolite, and silica gel, and then dried to a moisture content of 12% to 2%. It can also be prepared.

  The bacterial solution can be prepared, for example, as follows.

  Bacillus pumilus TUAT1 strain (NITE BP-1356) was cultured in 5 liters of NFb liquid medium containing 1 g / liter of ammonium chloride for 1 week with shaking at 25 ° C and collected by centrifugation at 4 ° C, 6000 rpm for 30 minutes. To do.

Next, 1 kg of black soil from the farm attached to Tokyo University of Agriculture and Technology passed through a 2 mm sieve was sterilized in an autoclave at 121 ° C for 40 minutes, and the collected cells were mixed in 100 mL of sterilized distilled water. Leave to stand for 1 week under field capacity and mature. In the above, the bacterial density of the inoculum is measured by a dilution plate method and adjusted to 1.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g.

  The plant disease control agent of the present invention is obtained by culturing Bacillus pumillus TUAT1 strain (NITE BP-1356) to a spore ratio of 100%. Therefore, long-term storage at room temperature (around 25 ° C.) becomes possible, and the number of bacteria and the effect thereof can be maintained over a long period (6 months or more). In addition, when applied, the roots of crops (especially rice) are improved.

  It has been confirmed that the growth of crops (especially rice) is increased by spore increase compared to non-inoculation or vegetative inoculation.

  It has been conventionally known that stress tolerance such as temperature and moisture can be enhanced by forming spores. The inventors of the present application, by setting the spore rate to 100% under the above-described conditions, can more effectively express characteristics such as growth promotion conventionally recognized in Bacillus bacteria, and in particular, applied crops ( For example, it has been found that the root area expansion of rice), root colony improvement, root weight increase effect, and nutrient absorption promotion effect are improved.

  As described above, after culturing Bacillus pumillus TUAT1 strain (NITE BP-1356), the trophozoites are completely killed by heat treatment at 65 ° C. to 80 ° C. for 60 minutes or more to obtain a spore ratio of 100%. be able to.

  According to the study by the inventors, the vegetative type is completely killed to a spore ratio of 100%, and then the root area of the applied crop is expanded, the root establishment is improved, the root weight is increased, the nutrient is absorbed. In order to effectively improve the accelerating effect and the like, it was desired to perform heat treatment for 60 minutes or more in a temperature range of 65 ° C to 80 ° C.

  Note that the heat treatment time of 60 minutes or more may be divided into a plurality of times, and the total heat treatment time may be 60 minutes or more.

  In addition, with a spore ratio of 100%, it is possible to effectively improve the root area of applied crops, improve root fixation, increase root weight, promote nutrient absorption, etc. In view of the above, it is desirable that the heat treatment in the temperature range of 65 ° C. to 80 ° C. does not exceed 70 minutes in total.

  The conditions for spore formation with a spore ratio of 100% are not particularly limited as long as the conditions for the heat treatment for 60 minutes or more in the temperature range of 65 ° C. to 80 ° C. are satisfied. For example, the cells are cultured on a Trypticase soy plate (20 ml medium, 9 cm diameter petri dish) at 28 ° C. for 10 to 14 days. Bacteria are collected from here, washed with physiological saline (3 times), collected again and suspended in physiological saline, and then heat-treated at 65 ° C. for 30 minutes, by repeating the above steps twice. The heating time at 65 ° C. is 60 minutes. The bacterial solution thus obtained can be stored refrigerated at 4 ° C., and the stored bacterial solution can be diluted with sterilized water and used for the plant disease control agent of the present invention.

When the above-mentioned fungal fluid is applied to a crop, the concentration of the fungus is 1. from the viewpoint of effectively improving the root area of the crop, improving root fixation, increasing the weight of the root, promoting nutrient absorption, and the like. 0 × is desirably ^{10 7 ~9.0 × 10 7 cfu /} g.

  The drying treatment is performed for the purpose of moisture adjustment until the moisture content becomes 12% to 2%.

In order to make the bacterium concentration in the plant disease control agent of the present invention 1.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g described above, it is desirable that the drying treatment is performed until the moisture becomes 2%. On the other hand, when the drying process is finished in a state where the water content exceeds 15%, even if the bacterial concentration of the bacterial solution at the time of manufacture is in the range of 1.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g In the subsequent storage, the number of bacteria is less than 10 ⁷ cfu / g, which is not preferable.

It should be noted that, when the concentration of the granular plant disease control agent after the drying treatment is set to 1.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g, the drying process performed for the purpose of moisture adjustment includes a high-temperature thermal power. Instead of drying, it is desirable to perform ventilation drying or fluidized bed drying. For example, the moisture can be adjusted to 12% to 2% by drying within 4 hours using a ventilation dryer.

  The above-mentioned plant disease control agent of the present invention is granulated in this manner, so that the number of bacteria and the effect thereof can be maintained for a longer period of time (long-term storage at normal temperature for one year or more). In addition, handling is improved, and it is applied as a granular plant disease control agent (for example, mixed and applied to the soil at the time of raising seedlings), thereby further improving the root fixation of crops and improving the fertilization effect. The disease control / control effect can be improved.

  In the above-described plant disease control agent of the present invention, a material composed of any one or a combination of diatomaceous earth, zeolite, and silica gel is granulated into a granular material, which is immersed in the above-described bacterial solution. Thereafter, drying and sieving are performed to obtain a granular plant disease control agent having an average particle diameter of 2 to 4 mm.

  Or, after adding and mixing the above-mentioned fungal liquid to a material composed of any one or a combination of diatomaceous earth, zeolite, and silica gel, granulating it, followed by drying and sieving to obtain an average particle size of 2 A 4 mm granular plant disease control agent is used.

  The granulation can be performed in various granulation formats regardless of the granulation format such as rolling granulation (drum, dish), extrusion molding (pellet), compression molding (briquette) and the like.

  Even if it is the granular plant disease control agent manufactured by any form mentioned above, it is desirable from the viewpoint of handling property that the hardness is 1 kgf or more.

  In the plant disease control agent of the present invention described above, the silicate material has improved lodging resistance and healthy seedling effect of rice. Thus, by using silica gel as a fertilizer material, or by using silica gel as a part of the fertilizer material, it is possible to improve the effects of increasing and reducing fertilizer in rice production.

  It is desirable that the material in the granular plant disease control agent of the present invention described above includes a porous material having a pore diameter of μm or more. In the granular plant disease control agent of the present invention, the size of the microorganism is 1 μm or more. Therefore, when a porous material having a pore diameter of μm or more is used, it is advantageous because microorganisms can be enclosed in the pores of μm or more.

  For example, diatomaceous earth (unfired) is a porous material having a pore size of μm or more, and is therefore useful as a porous material for encapsulating Bacillus spp.

  In the case of using a combination of a plurality of types of materials described above, for example, silica gel and diatomaceous earth (not fired) are used in a ratio of 7: 3 by weight, and the total weight is 1.2-3. % Binder (eg starch) is added and mixed and molded (granulated). On the other hand, after culture | cultivating Bacillus genus bacteria, the fungi for the plant disease control agent of this invention which were heat-processed in the temperature range of 65 to 80 degreeC for 60 minutes or more and made the spore ratio 100% are prepared. And the granular material prepared as described above is added in an amount equal to the amount of the bacterial solution and immersed for 1 hour. Thereafter, the bacterial solution is removed by decantation and dried by ventilation (70 ° C., 4 hours) to obtain the granular plant disease control agent of the present invention having a moisture content of 2 to 12%.

  In addition, in the above, the binder (for example, starch) added in a weight ratio of 1.2 to 3% with respect to the total weight of the material composed of any one or a combination of diatomaceous earth, zeolite, and silica gel Is added for the purpose of disintegrating the applied plant disease control agent of the present invention immediately after application but about one week after application. As long as it is a binder for agricultural materials used for such a purpose, various things well-known in this technical field can be used.

  Using a field in Nihonmatsu City, Fukushima Prefecture, we investigated the rice blast suppression and plant disease control effects of the granular plant disease control agent of the present invention.

  The granular plant disease control agent used was provided by Asahi Kogyo Co., Ltd., and was prepared in the amount necessary for the study according to the following procedure.

  Silica gel and diatomaceous earth (unfired diatomaceous earth) were mixed at a weight ratio of 7: 3 (adding starch with a total weight of 3% as a granulation accelerator (binder)) to prepare a granular material.

Antibiotic-resistant strain (TUAT1SR8 strain) that imparted rifampsin and streptomycin resistance to TUAT1 strain was inoculated into 10 Erlenmeyer flasks containing 200 ml Trypticase soy broth liquid medium, and cultured for 11 days at 28 ° C. and 110 rpm. After the culture, heat treatment was performed at 65 ° C. for 1 hour, and centrifugation was performed at room temperature at 8,000 rpm for 10 minutes. After centrifugation, the cells were washed three times with physiological saline, suspended in 2 liters of physiological saline, and adjusted to a bacterial concentration of 1.0 × 10 ⁷ cfu / ml to prepare a bacterial solution.

200 g of the granular material prepared as described above was placed in a stainless bat sterilized with 70% ethanol, 200 ml of the prepared bacterial solution was added, and the immersion treatment was performed for 1 hour. After the treatment, drying was performed using a ventilator at 70 ° C. for 4 hours. After drying, it was refrigerated at 4 ° C. until used for each test. The fungus concentration was adjusted to 1.0 × 10 ⁷ cfu / g.

The above-mentioned field (treated area) is a non-inoculated area, the area inoculated with the above-mentioned fungal liquid (bacterial concentration: 1.0 × 10 ⁷ cfu / ml), the granular plant disease control of the present invention prepared as described above. Examination was carried out by dividing into groups inoculated with the agent (bacterial concentration: 1.0 × 10 ⁷ cfu / g).

In the section inoculated with the above-mentioned bacterial liquid (bacterial concentration: 1.0 × 10 ⁷ cfu / ml) (hereinafter, sometimes referred to as “spore bacterial liquid inoculation” in the present specification and drawings), one seedling box One liter of the bacterial solution was inoculated once a week for a total of 3 times.

A group inoculated with the granular plant disease control agent of the present invention (bacterial concentration: 1.0 × 10 ⁷ cfu / g) (hereinafter, sometimes referred to as “formulation” in the present specification) prepared as described above. Hereinafter, in this specification and drawings, it may be expressed as “TUAT1 formulation inoculation”), and seedling boxes were prepared and inoculated using a soil mixed with 1 kg of the formulation per 20 kg of the seedling culture soil.

  In the three treatment areas, seedling boxes were prepared and sowed on May 16, rice planting was conducted on June 7, and rice blast lesions were examined on August 7. The rice cultivar is “Isokawa”.

  Moreover, the growth investigation was conducted at the time of rice planting, at the highest tillering time, and at the harvest period, and the growth promotion effect of rice by the granular plant disease control agent of the present invention was examined.

  The results of the growth survey at the time of rice planting are shown in FIGS.

  In both the spore-inoculated group and the TUAT1 preparation-inoculated group, the increase in root weight, that is, the growth promotion effect of rice was confirmed compared with the non-inoculated group.

  The results of the rice blast lesion survey conducted on August 7 are shown in FIG.

  Significant suppression of lesions was observed in the TUAT1 preparation inoculation group than in the non-inoculation group. On the other hand, although a slight decrease was observed in the spore-inoculated group, no significant inhibitory effect was observed compared to the non-inoculated group.

(Effect confirmation test 1)
A rice blast inoculation test was conducted by pot cultivation.

  The experimental conditions of the test were the conditions shown in FIG. FIG. 5 shows the growth state of rice during 4 weeks of cultivation.

  The bacterial solution used for the granular plant disease control agent of the present invention was prepared under the conditions shown in FIG. 4, and the inoculated group (TUAT1 inoculation) showed that the roots were significantly developed compared to the non-inoculated group. It was confirmed (FIG. 5).

  The blast disease inoculation conditions were as shown in FIG.

  The result was as shown in FIG.

  As shown in the examination results shown in FIG. 7, a significant effect of reducing the number of lesions could be confirmed by inoculating the bacterial solution used for the granular plant disease control agent of the present invention.

As a result of this test, Bacillus pumillus TUAT1 strain (NITE BP-1356) was cultured and then heat-treated in a temperature range of 65 ° C. to 80 ° C. for 60 minutes or more, with a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^7. It can be confirmed that the bacterial solution of ˜9.0 × 10 ⁷ cfu / g can exhibit the effect of suppressing and controlling rice blast.

  That is, it is recognized that Bacillus pumillus TUAT1 strain (NITE BP-1356) exhibits the effect of suppressing and controlling rice blast.

(Effect confirmation test 2)
As in Example 1, according to the granular plant disease control agent of the present invention, it has been confirmed that the suppression and control effects of rice blast are exhibited.

  However, as shown in Examination Test 1, it has been confirmed that even the bacterial solution used for the granular plant disease control agent of the present invention exhibits the effect of suppressing and controlling rice blast.

On the other hand, according to the effect confirmation test 1, after culturing Bacillus pumillus TUAT1 strain (NITE BP-1356), the spore ratio is 1% at a spore ratio of 100% obtained by heating at 65 ° C to 80 ° C for 60 minutes or more. 0.0 × 10 ^{7 to} 9.0 × 10 ⁷ cfu / g of the bacterial solution exerts the suppression and control effects of rice blast, and Bacillus pumillus TUAT1 strain (NITE BP-1356) suppresses and controls rice blast It is recognized to be effective.

  Therefore, for the suppression and control effect of rice blast by the granular plant disease control agent of the present invention, any of the materials used in the granular plant disease control agent of the present invention (diatomaceous earth, zeolite, silica gel) A secondary effect due to silicon contained in one or a combination of materials.

  Then, the granular plant disease control agent of this invention and the granular material which consists only of the material used for this granular plant disease control agent were compared and examined.

  The test conditions are as shown in FIG. In FIG. 8, Bacillus pumillus TUAT1 inoculum is the granular plant disease control agent of the present invention. On the other hand, the “inoculation holding agent control” is a granular material composed only of materials used for the granular plant disease control agent.

  The examination results are shown in FIG.

  There was a tendency for the number of lesions in the top three leaves to decrease in rice inoculated with Bacillus pumillus TUAT1 inoculum.

  As a result, the suppression and control effect of rice blast by the granular plant disease control agent of the present invention confirmed in Example 1 was confirmed in the effect confirmation test 1, and Bacillus pumillus TUAT1 strain (NITE BP-1356). It was recognized that

  The preferred embodiments and examples of the present invention have been described above, but the present invention is not limited to the above-described embodiments and examples, and variously within the technical scope grasped from the description of the claims. It can be changed.

Claims (4)

Bacillus pumillus TUAT1 strain (NITE BP-1356) is cultured and then heat-treated at a temperature range of 65 ° C. to 80 ° C. for 60 minutes or more with a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^{7 to} 9.0 ×. A plant disease control agent comprising a bacterial solution of 10 ⁷ cfu / g. Bacillus pumillus TUAT1 strain (NITE BP-1356) is cultured and then heat-treated at a temperature range of 65 ° C. to 80 ° C. for 60 minutes or more with a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^{7 to} 9.0 ×. After dipping a granular material consisting of any one or a combination of diatomaceous earth, zeolite, and silica gel in 10 ⁷ cfu / g of bacterial solution, dry treatment until the water content is 12% to 2%. A granular plant disease control agent. Bacillus pumillus TUAT1 strain (NITE BP-1356) is cultured and then heat-treated at a temperature range of 65 ° C. to 80 ° C. for 60 minutes or more with a spore ratio of 100% and a bacterial concentration of 1.0 × 10 ^{7 to} 9.0 ×. After adding and mixing 10 ⁷ cfu / g of bacterial solution to a material composed of any one or a combination of diatomaceous earth, zeolite, and silica gel, and granulating it, until moisture reaches 12% to 2% A granular plant disease control agent obtained by drying treatment.   The granular plant disease control agent according to claim 2 or 3, wherein the material includes a porous material having a pore size of not less than µm.