JPH04360678A - New fungi strain of drechslera sp. and weed controller containing the same fungi - Google Patents

Abstract

PURPOSE:To obtain a herbicide for control of Deccan grass having safeness to circumference and high selectivity. CONSTITUTION:A new fungi strain of the genus Drechslera exhibiting no pathogenicity to culture plant and exhibiting to Echinochloa oryzicola, Echinochloa coronam, variant crus-galli of Echinochloa crus-galli, variant of Echinochloa crus-galli and weed controller containing these same yeasts. The controller provides practical control effect on Deccan grass. Furthermore, weed controller containing the new fungi stain of the genus Drechslera contributes to avoidance of appearance of environmental pollution and chemical resistant weed which becomes problem at present.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates to a novel microorganism and a weed control agent containing the same.

0002

BACKGROUND OF THE INVENTION Approximately 100 years ago, methods for controlling weeds and pests shifted from cultivation methods to chemical methods. In particular, the dramatic development of synthetic organic pesticides such as DDT in the mid-1900s led to improvements such as increased yields, improved quality, and labor savings in agricultural crops, leading to rapid improvements in world food production.

However, in recent years, environmental pollution due to excessive use of synthetic organic pesticides and the emergence of pests and weeds that have acquired drug resistance have become serious problems. Therefore, the development of chemical pesticides in recent years has clearly become oriented towards high performance. In other words, it is desired to have a compound that is not only safe for humans and livestock but also exhibits an excellent control effect at a low dose, and has sufficient consideration for persistence, environmental pollution, and the like. Furthermore, pesticide-free cultivation methods that produce crops without the use of chemical pesticides have recently attracted attention. As described above, as the effects of chemical pesticides on the human body and the natural environment have become a focus of attention, interest in biological pesticides has increased, and research and development of biopesticides has become active. In particular, there are great expectations for the development of microbial pesticides that directly utilize the living organisms of microorganisms or microbially sourced pesticides that utilize physiologically active substances produced by microorganisms.

[0004] However, pesticide-free cultivation methods and biological control methods are still in the process of being researched, and it is also true that a stable control effect cannot be obtained and sufficient crop production cannot be expected with their sole application.

[0005] Whichever method is used, reducing the amount of applied organic synthetic agricultural chemicals is of great significance from the viewpoint of safety.

In the field of herbicides, research and development of microbial herbicides that utilize pathogenic microorganisms against weeds has progressed mainly in the United States, and so far, the pathogenic microorganism Phytophysora spp. Palmirola species (Phyto
phthora palmirola), DeVine (trade name, Abbott, Inc.), legume weeds, and Northern joint vetch (Aeschyn).
Colletotrichum genus Gloeosporioides sp.
Collego (trade name, Ecogen Inc.), etc., which utilizes Collego trichum gloeosporioides, are on the market. However, there is no known research on microbial herbicides targeting the genus Millet, which is a major weed in the cultivation of major crops such as wheat, rice, and soybean.

[0007] Wild barnyard grass is known as a weed in rice-growing areas around the world, and has long been a problem as a typical paddy field weed, particularly in Japan. It is said that the occurrence of barnyard grass in rice fields made rice transplantation work inevitable. According to Yabuno, the barnyard grass found in the wild around the world is of the genus Echinochloa origicolla (
Echinochloa oryzicola, Echinochloa coronum sp., Echinochloa pyramidis sp.
dalis), Echinochloa stagnina sp. (Ech
inochloa stagnina), Echinochloa haploclada species (Echinochloa hap
loclada) and Echinochloa crusugali sp.
chinochloa crus-galli), and the species is further classified into three varieties: formocensis, crus galli, and platycolla (Weed Research (1975) vol. 20). ). These varieties differ in their responses to herbicides and pathogens. The naturally occurring weed, barnyard grass, is considered to be a hybrid of various species of the genus Echinochloa, and a herbicide that exhibits a practical control effect must have a herbicidal effect on all species of the genus Echinochloa.

[0008]

OBJECTS OF THE INVENTION The present invention solves the above-mentioned disadvantages in crop production, avoids environmental pollution and the appearance of resistant weeds, and provides weed control that enables practical control. and weed control compositions. That is, we isolated from nature a filamentous fungus of the genus Drechlera that is pathogenic only to barnyard grass, and further discovered that there are strains of the genus Drechlera that have herbicidal activity against all species of the genus Echinochloa. An object of the present invention is to provide a weed control agent containing the viable bacterial cells.

[0009]

[Means for Solving the Problems] The present inventors searched for various pathogenic microorganisms with the aim of controlling barnyard grass, which is an important weed in rice fields and fields, and found that they had a herbicidal effect on barnyard grass. discovered a new Drechlera bacterium that is not pathogenic to useful plants such as rice, and completed the present invention.

[0010] The barnyard grass that is the object of the present invention is a weed belonging to the genus Echinochloa of the Poaceae family, and specifically, the barnyard grass (Echinochloa oryzicola).
, Echinochloa crus
-galli var. formosensis)
, Echinichloa crus-ga
lli var. Echinochloa crus-galli), Echinochloa crus-galli
var. praticola), Echinoch
loa colonum, Echinochloa
pyramidalis, Echinochloa
stagnina, Echinochloa hapl
oclada et al.

[0011] That is, the microorganism according to the present invention can be applied to cultivated plants, rice, barley, wheat, rye, oat,
It does not show any pathogenicity to corn, sorghum, millet, grasses, orchard grass, Italian rye grass, perennial rye grass, sweet vernal grass, tall fescue, meadow fescue, med fescue, etc., and does not show any pathogenicity to Echinochloa orijicola species, Echinochloa genus Crusgari species, Echinochloa genus Coronaum species, etc. This is a new strain of Drexlera monoceras that is pathogenic to.

[0012] The new strain of the Drexlera monoceras species of the present invention includes MH4418 (Feikoken Bibori No. 12034).
, or MH5011 (Feikoken Bibori No. 12035),
Or, MH5017 (Feweral Research Institute No. 11993), or MH5018 (Featured Research Institute No. 11994), or MH5511 (Featured Research Institute No. 12130), or MH9011 (Featured Research Institute No. 12129). ) is included.

[0013] The pathogenic microorganism was isolated from naturally diseased barnyard grass, and its pathogenicity to barnyard grass and rice was tested. As a result, it was found to have strong pathogenicity against all species of the genus Echinochloa, which is a weedy barnyard grass, and to be highly pathogenic to rice. We selected those that did not show any pathogenicity. As a result of identifying the selected microorganisms based on the morphology of their conidia, it was found that all of them were classified into the genus Drechlera, and the present invention was completed.

[0014] The microorganism according to the present invention can be used as a weed control agent by directly using viable microorganisms obtained by culturing, by using the filtrate after culturing the microorganisms, or by a combination of both. There are various methods to use. Furthermore, the microorganism according to the present invention can be used alone by suspending conidia and hyphae obtained by culturing in a nutrient medium in an aqueous solution containing a surfactant, or when used with other herbicides that do not exhibit antagonistic properties. In some cases, it is used in combination with chemical pesticides such as disinfectants, fungicides, and insecticides. When using the microorganism according to the present invention as a weed control agent, conidia are more desirable as they are more durable than hyphae. The microorganisms related to the present invention can be grown using either a liquid medium or a solid medium.
Inoculate into a liquid medium such as dextrose and multiply the bacterial cells.
Conidia are formed by crushing the obtained bacterial cells and drying them. In the case of a solid medium, conidia formation is promoted by inoculating a potato dextrose agar medium or the like, removing grown aerial mycelia, and then drying.

As mentioned above, the microorganism according to the present invention is capable of mass culturing of conidia and mycelium, and can be used industrially as a weed control agent. , for example, when treated at the time of transplanting rice to paddy fields, it exhibits herbicidal action only against the weed barnyard grass,
Non-pathogenic to cultivated plants such as rice, barley, wheat, rye, oat, corn, sorghum, millet, grasses, orchard grass, Italian rye grass, perennial rye grass, sweet vernal grass, tall fescue, meadow fescue, med fescue, etc. It was found that a significant herbicidal effect can be obtained.

[0016] To use the weed control agent according to the present invention as a herbicide, the cells of the genus Drexlera may be used as they are, but in general, the cells of the genus Drexlera may be used on an inert solid carrier or It is desirable to mix it with a liquid carrier and prepare it into commonly used formulations such as granules, flowables, wettable powders, emulsions, and liquids.

[0017] As the carrier, any solid or liquid carrier that is generally used in agricultural and horticultural chemicals and is biologically inert can be used, and the carrier is not limited to a specific carrier.

For example, solid carriers include mineral powders such as clay, talc, bentonite, calcium carbonate, diatomaceous earth, and white carbon, vegetable powders such as soybean flour and starch, and polymers such as polyvinyl alcohol and polyalkylene glycol. Examples include compounds. Examples of liquid carriers include various organic solvents such as decane and dodecane, vegetable oils, mineral oils, and water.

The content of Drexlera in the weed control agent according to the present invention is 102 to 101 as spores.
5 pieces, preferably 106 to 1012 pieces.

[0020] As adjuvants, surfactants, binders, stabilizers, etc. commonly used in agricultural and horticultural chemicals can be used singly or in combination as required. As a stabilizer,
For example, using antioxidants, pH adjusters, etc., and sometimes
Light stabilizers are also used.

[0021] The content of the adjuvant is 0 to 80% by weight,
The content of the carrier is 100% by weight minus the active ingredient and content.

[0022] When the weed control agent of the present invention is used in a field, the amount of conidia of Drechlera bacteria is 1.
02 to 1015pore/10a, preferably 10
7 to 1012 pores/10a.

[0023]

[Examples] New strains of the genus Drexlera and weed control agents containing them according to the present invention will be specifically explained below, but the present invention is not limited thereto.

Test Example 1 Isolation/Selection Method and Identification of Microorganisms 1) Isolation Method of Pathogenic Microorganisms Collect naturally diseased barnyard grass and isolate 10 specimens focusing on lesions.
Tissue sections of ~20 mm were prepared, immersed in a 70% ethyl alcohol aqueous solution for 1 to 2 seconds, and then immersed in a sodium hypochlorite aqueous solution with an effective chlorine concentration of 2% for 10 minutes to perform surface sterilization. The surface-sterilized lesion tissue was washed three times with sterile distilled water, placed on a non-nutrient agar medium, and incubated at 25°C.
Static culture was performed for 72 hours in a thermostat. After culturing, the hyphal tips of the grown filamentous fungi were isolated as single hyphae under a stereoscopic microscope, and purified on a nutrient medium, yielding over 5,000 bacterial strains. Among them, promising strains, MH-0015, MH-00
42, MH-0060, MH-0122, MH-188
9, MH-2653, MH-2679, MH-2781
, MH-2883 MH-2895, MH-4415
, MH-4418, MH-5011, MH-5017,
MH-5018, MH-5515, MH-9011 strains, etc. were obtained. The isolated filamentous fungi were tested for pathogenicity to barnyard grass and safety to rice.

2) Assay of pathogenicity of isolated microorganisms to barnyard grass and safety to rice Barnyard millet and rice (variety: Nipponbare) were grown aseptically in a test tube and used as test materials. That is, surface sterilization was performed by immersing barnyard grass and rice seeds in a 70% ethyl alcohol aqueous solution for 1 to 2 seconds and then immersing them in a sodium hypochlorite aqueous solution with an effective chlorine concentration of 2% for 10 minutes. The surface-sterilized seeds were washed three times with sterile distilled water, then sown in a non-nutrient liquid medium in a previously sterilized test tube, and the seedlings were raised in a plant growth chamber to the 1.5 leaf stage.

On the other hand, each of the isolated microorganisms was plate cultured on a potato dextrose agar medium, and a bacterial flora disk prepared by punching out the outer edge of the bacterial flora with a sterilized cork borer was used as an inoculum source.

[0027] The microbial flora disk was inoculated into a liquid medium in a test tube in which barnyard grass and rice were grown, and after culturing in a chamber for plant growth for 10 days, the microorganisms were found to be pathogenic to barnyard grass and rice as shown below. Evaluation was made on a four-level scale from - to +++. The results are shown in Table 1 (Table 1).

+++; Withering ++; Significant growth inhibition +: Slight growth inhibition −;No effect

[0029] The MH-0003 strain is a strain of Drechslera sp. MH-000.
7 strains are Phoma sp. MH-
Strain 0011 is a strain of Fusarium spp.
p. ), both of which were tested for comparison.

[0030]

[Table 1]

3) Identification of microorganisms A strain that showed remarkable pathogenicity to barnyard grass and had no effect on rice was identified. As a result, MH-0015, MH-1889, MH-26
53, MH-2679, MH-4415, MH-44
18, MH-5011, MH-5017, MH-501
8, MH-5515, and MH-9011 strains were plate-cultured on a malt agar medium at 28° C. for 7 days, and the colonies reached a diameter of 65 to 75 mm and showed irregular growth. The color of the colony is grayish black, there are marks on the conidia, and the size is 15 to 17.5 μm in width and 87.5 μm in length.
The diameter is 5 to 127.5 μm, and the shape is slightly curved. Most of the conidia have 5 to 7 septa, and the shape of the conidiophore is straight. From the above characteristics, MH-0015, MH-1
889, MH-2653 MH-2679, MH-4
415, MH-4418, MH-5011, MH-50
17, MH-5018, MH-5515, MH-901
All 1 strains were Drexlera monoceras (Dr.
echsleramonoceras).

MH-0042, MH-0060, MH-
The 2883 strain has no conidia, and the size is 1 in width.
The length is 7 to 22 μm, and the length is 40 to 90 μm. The shape of the conidia is cylindrical and some are curved, and the septum is one
~5 pieces. From the above characteristics, MH-0042, MH
-0062, MH-2883 strain is Drechslera ravenellii
was identified.

MH-0122, MH-2781, MH-
The 2895 strain was cultured on malt agar medium at 28°C for 7 days until the colony size was 20 to 2 mm in diameter.
It reaches 5mm. The color of the colony is light gray, with a gray-green center and a gray-black underside. The conidia have no scars and are 20 to 25 μm wide and 55 to 95 μm long. Conidia have 5 to 6 septa, and the shape of the conidiophore is straight. From the above characteristics, MH-0122, MH-278
1. MH-2895 strain is a strain of Drexlerapore (Dr.
It was identified as echslera poa).

Furthermore, MH-2990 and MH-2998 strains were also identified as Drechslera sp. based on their flora and the shape of conidia.

On the other hand, MH-0003, which did not show any pathogenicity to barnyard grass, was found in the genus Drechlera (Drec.
hslera sp. ), MH-0011 strain is Fusarium sp., MH-0007
The bacterial strain was identified as Phoma sp.

The above identification was carried out by M. B. Ellis
(1971) Demariaceus Hyphom
ycetes p. 608, Commonwealth
h Mycological Institute,
Kew, England and M. B. Elli
s (1976) More Demariaceus
Hyphomycetes p. 507, Comm
onwealth Mycological Instrument
Itute, Kew, England.

MH-0015, MH-0042, MH-
0060, MH-0122, MH-1889, MH-2
653, MH-2679, MH-2781, MH-28
83MH-2895, MH-4415, MH-4418
, MH-5011, MH-5017, MH-5018,
MH-5515, MH-9011 strains, etc. have been deposited at the Microtech Institute.

[0038] The Drexlera bacterium (Dr.
echslera spp. ) is not listed as a pathogen in the National Institute of Health's Pathogen Safety Management Regulations, and is guaranteed to be safe for humans and livestock.

Test Example 2 Effect of controlling barnyard grass by bacteria of the genus Drechlera Drechlera genus isolated from nature was inoculated onto an oatmil agar medium and statically cultured at 25°C for 7 days. Thereafter, formation of conidia was promoted by removing aerial hyphae with distilled water. The resulting conidia were mixed with 0.02% Triton
100 (trade name/manufactured by Rohm & Haas) in an aqueous solution to prepare a weed control agent containing Drechlera as an active ingredient.

On the other hand, barnyard grass and rice (variety: Nipponbare)
The seeds were sown in 1/10000a pots in paddy soil, and the seedlings were raised to the 1.5 leaf stage. Water depth is approximately 3cm
After waterlogging, 5 ml of the above-mentioned weed control agent containing conidia of Drexlera was added dropwise, and after cultivating for 10 days in an artificial climate room at 30°C during the day and 25°C at night, Drechlera was grown. The effects on barnyard grass and rice were evaluated using the same criteria as Test Example 1. The results are shown in Table 2 (Table 2).

+++; Withering ++; Significant growth inhibition +: Slight growth inhibition −;No effect

[0042]

[Table 2]

As a result of the test, MH-4415, MH-4418, MH-501 of Drexlera according to the present invention
1, MH-5017, MH-5018, MH-5511
, MH-9011 is MH-0015 to M
It exhibited a herbicidal effect 100 to 1000 times better than H-2998, and was also found to be safe for rice.

Test Example 3 The pathogenicity of the microorganisms of the present invention against various species of the genus Echinochloa and rice was evaluated in the same manner as in Test Example 1-2). That is, as barnyard grass, Echinochloa genus Coronanum species, Echinochloa genus Orijicola species (Japanese name: Tainubier),
Formocensis (variety of Echinochloa spp. Cursugali)
Japanese name: Himetainubier), Echinochloa Kurusugali variety Kurusugali (Japanese name: Inuvie), and Echinochloa Kurusugali variety Platycola (Japanese name: Himeinubie), cultivated varieties Nipponbare (variety name), Sasanishiki (Japanese name). We tested Koshihikari (variety name) and Koshihikari (variety name). Ten days after inoculation, the pathogenicity of the microorganism according to the present invention to barnyard grass and rice was evaluated, and the results are shown in Table 3 (
It is shown in Tables 3 and 4).

[0045]

[Table 3]

[0046]

[Table 4] +++; Withering ++; Significant growth inhibition +: Slight growth inhibition −;No effect

As a result of the test, MH4418, MH5011, MH
5017, MH5018, MH5511 and MH901
Strain 1 had strong pathogenicity against all species and varieties of the genus Echinochloa and exhibited excellent herbicidal activity, and was also found to be safe against rice.

Formulation Example Next, a formulation example of the herbicide according to the present invention will be shown as an example.

Example 1 (Granules) After thoroughly mixing 2% by weight of Neoperex (trade name/manufactured by Kao), 2% by weight of Sunextract P252 (trade name/manufactured by Sanyo Kokusaku Pulp), and 96% by weight of zeolite, A spore suspension containing 10 9 conidia of Drechlera (strain MH-5018) per gram of granules was added and moistened, followed by extrusion and granulation using a small injection molding machine. After drying this by air drying and crushing it, granules with a size of 0.3 to 2 mm were obtained using a granulator.

Example 2 (Granules) After thoroughly mixing 2% by weight of Neoperex (trade name/manufactured by Kao), 2% by weight of Sunextract P252 (trade name/manufactured by Sanyo Kokusaku Pulp), and 96% by weight of zeolite, A spore suspension containing 10 8 conidia of Drechlera (strain MH-5511) per gram of granules was added to moisten the mixture, and then extruded and granulated using a small injection molding machine. After drying this by air drying and crushing it, granules with a size of 0.3 to 2 mm were obtained using a granulator.

Example 3 (Granules) After thoroughly mixing 2% by weight of Neoperex (trade name/manufactured by Kao), 2% by weight of Sunextract P252 (trade name/manufactured by Sanyo Kokusaku Pulp), and 96% by weight of zeolite, A spore suspension containing 109 conidia of Drechlera (strain MH-9011) per gram of granules was added to moisten the mixture, and then extruded and granulated using a small injection molding machine. After drying this by air drying and crushing it, granules with a size of 0.3 to 2 mm were obtained using a granulator.

Example 4 (hydrating powder) 2% by weight of Neoperex (trade name/manufactured by Kao), 2% by weight of Triton (X-100), and 5% by weight of White Carbon were added to Drexlera (MH-4418 strain). ) impregnated with a spore suspension containing 1010 conidia per 1 g of wettable powder,
After air drying, 91% by weight of diatomaceous earth was thoroughly ground and mixed to obtain a wettable powder.

Example 5 (hydrating powder) Neoperex (trade name, manufactured by Kao; sodium dodecylbenzenesulfonate): 2% by weight, Neugen EA80 (
Product name, manufactured by Sanyo Chemical; polyoxyethylene nonylphenyl ether): 1% by weight, white carbon: 5% by weight
and 92% by weight of diatomaceous earth.
-5511 strain) per 1g of hydrating powder.
After being impregnated with a spore suspension containing 1,000 spores and air-dried, the mixture was thoroughly ground and mixed to obtain a wettable powder.

Example 6 (Flowable agent) 10% by weight of Sunextract (P252) dissolved in 80% by weight of water was wet-pulverized and mixed, and then Drexlera (MH-50)
101 conidia of 17 bacterial strains per ml of flowable agent.
Kelzan S dissolved in 9.6% by weight of spore suspension containing 0 spores
(trade name, manufactured by Kelco) 0.4% by weight was added and mixed to obtain a flowable agent.

Example 7 (Flowable agent) 10% by weight of Sunextract P252 (trade name, same as above) dissolved in 70% by weight of water, and 10% by weight of Drechslera (MH-
5511 strain) per ml of flowable agent.
After mixing 10% by weight of a spore suspension containing 0.010 spores, the mixture was wet-pulverized and mixed, and then 0.2% by weight of Kelzan S (trade name, manufactured by Kelco; xanthan gum) dissolved in 9.8% by weight of water was added and mixed. , obtained a flowable agent.

Example 8 (Dry flowable agent) Sodium alkylbenzenesulfonate: 15% by weight, polypropylene glycol polyethylene glycol ether: 85% by weight, and Drechlera (MH-5)
A dry flowable agent was obtained by mixing 1010 conidia of 011 strain) per 1 g of a dry flowable agent.

Example 9 (Powder) Emulgen 910 (trade name, manufactured by Kao; polyoxyethylene nonylphenyl ether): 0.5% by weight and kaolin clay: 99.5% by weight were thoroughly pulverized and mixed, and Drechlera sp. A powder was obtained by mixing 10 8 conidia of the fungus (MH-9011 strain) per 1 g of powder.

Example 10 (Emulsion) 1010 conidia of Drechslera (MH-5511 strain) were suspended in 5% by weight of lecithin and 94% by weight of heavy white oil, and an equal amount of 1 Triton X in weight%
-100 was added and mixed to form an emulsion to obtain an emulsion.

[0059]

Effects of the Invention The new strain of the genus Drexlera monoceras according to the present invention was found to be pathogenic to all species of the genus Echinochloa, which is a weedy barnyard grass, and showed practical herbicidal activity against barnyard grass. Furthermore, it was confirmed that it is extremely safe for cultivated plants such as rice.

[0060] The microorganisms used in the present invention are selected from microorganisms in the natural world, and are safe without the fear of environmental pollution that is a concern with organic synthetic pesticides.

As described above, the weed control agent according to the present invention not only contributes to crop production, but also contributes to avoiding environmental pollution and the appearance of drug-resistant weeds, which have become problems in recent years.

Claims (4)

[Claims] Claim 1: Non-pathogenic to cultivated plants, but pathogenic to Echinochloa orijicola species, Echinochloa coronavirus species, Echinochloa crusugali species variety formocensis, Echinochloa crusugali species variety formocensis, and Echinochloa crusugali species variety Platycola. A new strain of Drexlera monoceras spp. 2. A new strain of the Drexlera monoceras species is MH4418 (Feikoken Bibori No. 12034), MH5011 (Feibokuken Bibori No. 12035), or MH5017 (Feibokuken Bibori No. 11993). , or M
H5018 (Feikoken Bibori No. 11994), or MH
5511 (Feikoken Bibori No. 12130), or MH9
The new bacterial strain according to claim 1, which is 011 (Feikoken Bibori No. 12129). 3. A weed control agent containing the new bacterial strain according to claim 1. 4. The new bacterial strain of claim 3 is MH4418 (Feikoken Bibori No. 12034), or MH5011 (Feibokuken Bibori No. 12035), or MH5017 (Feibokuken Bibori No. 11993), 4. The weed control agent according to claim 3, which is MH5018 (Feikoken Bokuyori No. 11994), MH5511 (Feikokuken Bikyoyo No. 12130), or MH9011 (Feikoken Bikyoyo No. 12129).