JPH10117769A - Microorganism belonging to the genus ascochyta and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject strain capable of selectively withering weeds belonging to the genus Scirpus of the family Cyperaceae without polluting or damaging an environment like an agrochemical material does, and without affecting crops such as rice by exhibiting a pathogenesis to Scirpus juncoides, etc. SOLUTION: This herbicide is obtained by containing a strain belonging to the genus Ascochyta such as Ascochyta sp. JT-1006 strain (FERM-BP-5692), sp. JT-1007 strain (FERM-BP-5963), sp. JT-1008 strain (FERM-BP-5694), sp. JT-1009 strain (FERM-BP-5695), and sp. JT-1010 strain (FERM-BP-5696) exhibiting a pathogenesis to either one of Scirpus junoides, Scirpus hotarui, Scirpus wallichii or Scirpus ineolatus, as an active ingredient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, Ascochyta (Asco
chyta ), and a herbicide and a method for controlling weeds using the strain.

[0002]

2. Description of the Related Art As a method for controlling weeds belonging to the genus Scirpus, which is a major weed in paddy fields and fields, a method using a chemical herbicide is mainly used. In recent years, from the problem of environmental pollution due to heavy use of chemical pesticides,
There is a demand for the development of a weed control agent and its use that do not rely on chemical pesticides, and there is high expectation for microbial pesticides using plant pathogenic bacteria. To date, DeVine (US, target weed: St
ranglervine, potato family, Collego (USA, target weed: Northern jointvetch, legume), BioMal (Canada, target weed: Round-leaved mallow, mallow family) are registered as pesticides and commercialized. However, no microbial herbicide has been developed for weeds belonging to the genus Cyperaceae. In addition, the main weeds in the paddy field are the firefly, Scirpus juncoides , and the fireflies, Scirpus hotarui.
), Scirpus wallichii or Scirpus ineolatus , pathogenic microorganisms belonging to the genus Ascokita are not known.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a means for controlling weeds belonging to the genus Firefly in the family Cyperaceae by using microorganisms.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, it has been found that some strains belonging to the genus Ascokita have an excellent control ability against fireflies of the genus Firefly. And completed the present invention.
That is, the present invention is a strain belonging to the genus Ascokita, which is pathogenic to any of dog fireflies, fireflies, taiwanyamai, or squirrel fireflies.

[0005] The present invention is also a herbicide characterized by containing, as an active ingredient, a strain belonging to the genus Ascokita, which is pathogenic to any of dog fireflies, fireflies, taiwanyamai or squirrel fireflies. Furthermore, the present invention is a method for controlling weeds using the above herbicide.

Hereinafter, the present invention will be described in detail. At first,
Novel strains of the present invention, Ascokita sp.JT-1006, Ascokita sp.JT-1007, Ascokita sp.JT-1008, Ascokita
The sp.JT-1009 strain and Ascokita sp.JT-1010 strain will be described. These strains collected diseased Cyperaceae fireflies from all over Japan, isolated pathogenic strains against Cyperaceae fireflies, and purely cultivated them. And a screening tool for non-pathogenicity to other crops, especially rice. The main mycological properties of the novel strain of the present invention are as follows.

[0007] It is an aerobic bacterium and can grow at a pH of 3-1.
3, preferably 5-7. The growth temperature ranges from 15 to 30 degrees, and the optimum growth temperature ranges from 25 to 30 degrees. The growth on the potato dextrose agar is thriving, and the colony has a large number of orange-brown small grains in a gray to olive hyphae in a radial to spiral manner, with few aerial hyphae. The conidia are colorless and similar to the genus Phoma, but have one partition at the center and are divided into two chambers, and are elliptical. The size of the conidia is about 5-10 µm x about 2-5 µm
m.

[0008] The mycological properties described above are described in the illustration of plant fungi (Kobayashi et al., 1992. P20-52, 384. National Rural Education Association) and Illustra.
ted Genera of imperfect Fungi, Fourth Edition (Bar
nett, HL and Hunter, BB 1987. P6-39, 178. Ma
As a result of conducting a search based on cmillan publishing Company), this strain was identified as a microorganism belonging to the genus Ascokita. Cucumber, as pathogens tomatoes are known microorganisms of several Ascochyta genus, also, as the microorganism Ascochyta genus are pathogenic to Cyperaceae Scirpus plants it is pathogenic to Scirpus maritimis Ascochy
As pathogenic to ta kurdistanica and Scirpus lacustris
Although two examples of cochyta lacustris are known, none of them show pathogenicity to the dog firefly, firefly, taiwanyamai or Japanese firefly, which are the target of the present invention. The above strain has been deposited with the National Institute of Advanced Industrial Science and Technology (1-1-3 Higashi, Tsukuba, Ibaraki, Japan) under the following numbers.

[0009] Ascokita sp. Strain JT-1006: FERM BP-5692
(Deposit date: October 3, 1996) Ascokita sp. JT-1007 strain: FERM BP-5693 (Deposit date: 1996
October 3, 2005) Ascokita sp. JT-1008 strain: FERM BP-5694 (Deposit date Heisei 8
October 3, 2005) Ascokita sp. JT-1009 strain: FERM BP-5695 (Deposit date Heisei 8
October 3, 2005) Ascokita sp. JT-1010 strain: FERM BP-5696 (Deposit date Heisei 8
It is not necessary to use a special method for culturing this strain, and a method similar to that of a known strain belonging to the genus Ascokita can be used. As the medium, any synthetic medium or natural medium can be used as long as the medium appropriately contains assimilable carbon sources, nitrogen sources, inorganic substances, and necessary growth promoting substances. Specific examples of the medium include potato dextrose agar medium (PDA) and Czapek agar medium. When culturing, the temperature should be 15-3
It is desirable to maintain the temperature at 0 degrees, preferably 25-30 degrees, and the pH at 3-13, preferably 5-7. When culturing for about 7-14 days under the above conditions, a sufficient amount of conidia is formed on the surface of the medium. This strain kills the weeds of the genus Cyperaceae in the paddy field or upland field,
It does not affect crops such as eggplant, soybean, perilla, cucumber, etc. in addition to grass crops such as rice, wheat, barley, and corn. This strain is capable of mass culture,
And a large amount of spores can be easily obtained.

Next, the herbicide and the control method of the present invention will be described. The microorganism used in the herbicide of the present invention includes
Ascokita sp.JT-1006 strain, Ascokita sp.JT-1007 strain, Ascokita sp.JT-1008 strain, Ascokita sp.JT-1009 strain, Ascokita sp.JT-1010 strain, etc. May be used.

The herbicide of the present invention can be formulated by suspending spores obtained by mass-culturing the above strain in water, but the method of formulation is not limited thereto. In this case, the spore concentration is 10 ⁶ to 10 ¹² / m
l is suitable, but not limited thereto. When suspending in water, auxiliary agents such as a surfactant and a spreading agent may be added. The microorganism as the main agent may be fresh one immediately after culturing, or one that has been once stored and reconstituted with a water-based one. As the preservation method, ultra-low temperature preservation (−80 ° C.), vacuum freeze-drying and the like, which are widely known as preservation methods of microorganisms, can be used. The control method of the present invention is carried out by spraying the herbicide on a field. The amount of application may be determined according to the degree of weed growth, but it is preferably applied so that the amount of spores is usually 10 ¹¹ to 10 ¹⁵ per 10 arels of the field.

The plant to be treated by the herbicide and the control method of the present invention is not particularly limited, but is particularly effective for plants belonging to the genus Firefly. Bulrush Examples of Scirpus plants here (Scirpus juncoides subsp. Hotarui),
Juncoides (Scirpus junkoides subsp. Juncoides ), Japanese yam (Scirpus wallichii) , Japanese fireflies (Scir
pus lineolatus) , Shizui (Scirpus nipponicus) , San Kakui (Scirpus triqueter) , Kangarei (Scirpus mucr )
onatus), Ukiyagara (Scirpus fluviatilis), Koukiya <br/> Gala (Scirpus planiculmis) or the like is not intended but is typically limited thereto. In addition, there is no particular limitation on the growth period of the plant to be controlled, and the plant can be widely controlled from a plant shortly after germination to a grown plant.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

[0014]

【Example】

1) Creation process of the novel strain of the present invention A weed or firefly of the genus Cyperaceae, which grows in a paddy field or an upland field and shows a symptom, is harvested, the diseased part is cut off, and the leaf is cut in a 70% ethanol solution. And then immersed in a solution of 1% sodium hypochloride and an equal amount of a 0.1% Tween 80 solution, and suspended in a solution of 1 to 3 seconds. The surface was sterilized by immersion for minutes. The leaf pieces are washed once with a 0.1% Tween 80 solution and twice with sterile water, and then placed on a PDA medium containing antibiotics.
After culturing for 2-5 days in a thermostat at 5 ° C, the periphery of the elongated colony was transferred to a new PDA medium and cultured to form conidia. Further, the conidia were stirred and cultured in a fresh PDA medium to obtain a single colony, thereby performing pure isolation of the microorganism.

For each of the isolated strains, the pathogenicity of the fireflies of the family Cyperaceae was examined again, and the effects on rice, wheat, corn, tomato and cucumber were examined. New strains Ascokita sp.JT-1006, Ascokita sp.JT-1007 that exhibit excellent herbicidal effects and do not affect rice, wheat, corn, tomato, and cucumber
Strain, Ascokita sp.JT-1008, Ascokita sp.JT-1009
A strain, Ascokita sp.JT-1010, was isolated.

2) Identification of the created strain The strain of the present invention was identified mainly by observing the conidial morphology. As a result, as described above, this strain was identified as a microorganism belonging to the genus Ascokita.

3) Mass cultivation and formulation method Sterile water is added to a microorganism belonging to the genus Ascokita grown on a PDA medium, and the mixture is stirred to prepare a high-concentration spore suspension. By dropping on a V-8 juice agar medium and diffusing it with a sterile L-shaped glass rod, it became possible to inoculate microorganisms on a large number of petri dishes (9 cm in diameter) at one time. As a result, about 6 × 10 ⁷ spores were produced per petri dish.

As described above, the microorganism of the present invention can obtain spores easily and in large amounts by culturing on a plate medium. Further, the obtained spores can be suspended in 10% skim milk and dried under vacuum to obtain a wettable powder. This wettable powder can be suspended in water, added with a surfactant such as Tween 80, and applied.

4) Virulence test for firefly Insect firefly seeds were cultured in a sodium hypochlorite solution (Sodium hypochlorite).
0.1% Tween 80 (Tween)
80) The surface was sterilized by suspending in the solution to which the solution was added and immersing for 1 to 3 minutes. The surface-sterilized seeds were sown in a medium in a test tube for plant growth which had been sterilized in advance and grown from the first to second leaf stage as test materials. The microorganism of the present invention was obtained by culturing mycelia obtained on a potato agar medium, punching out two pieces of discs with a cork borer, and inoculating the test tubes into the test tubes. After 10 days in a constant temperature room at 25 ° C., the control rate of the firefly was examined. The results are shown in Table 1.
The fungus mortality of the firefly was 100%, and the control effect was 100%.

[0020]

As is evident from Table 1, the microorganism of the present invention showed an excellent control effect on Scirpus juncoides .

5) Virulence Test for Firefly Weeds The test for Firefly weeds was carried out in the same manner as the test for pathogenicity for Canine fireflies.
It was made into pieces. Firefly, Taiwan yamai, Japanese firefly and Shizui were used as test plants. The test results are shown in Table-2.

[0023]

As is evident from Table 2, the microorganism of the present invention showed an excellent control effect on weeds belonging to the genus Firefly in the family Cyperaceae. Similar results were obtained with other strains.

6) Influence on crops Tests on crops were carried out in the same manner as in the test for pathogenicity against firefly, and the spore concentration of the inoculum used was 10 ^7.
Pieces / ml. Rice, wheat, corn, eggplant, soybean, perilla, and cucumber were used as test plants. The test results are shown in Table-3.

[0026]

As is clear from Table 3, the microorganism of the present invention did not affect the growth of rice, wheat, corn, eggplant, cucumber, perilla, and soybean.

Formulation Example 1 (Solution) Conidia (10 ¹⁰ ) of Ascokita sp. JT-1008 strain and Tween 80 (1 g) were added to 1 L of water and mixed to prepare a solution.

[Formulation Example 2] (Wettable powder) 1 ml of a mixture of 9% maltose, 1% clay and 90% water
10 ⁸ conidia (JT-1007 strain) were suspended. After air-drying, the dried product was mixed and pulverized to prepare a wettable powder.

Formulation Example 3 (Wettable powder) 10 ⁸ conidia (JT-1006 strain) were suspended per 1 ml of a mixture of skim milk 10% and water 90%. After vacuum drying, the dried product was mixed and pulverized to prepare a wettable powder.

Formulation Example 4 (Powder) 14% hydroxypropyl-β-cyclodextrin
White carbon 12%, 74% of the mixture 1g per conidia clay (JT-1009 strain) 10 ⁸ were mixed. After drying, the powder was uniformly ground to prepare a powder.

Formulation Example 5 (granules) 10 ⁸ conidia (JT-1010 strain) per gram of a mixture of 15% β-cyclodextrin, 2% starch, 18% bentonite, 36% calcium carbonate, and 29% water After adding and kneading, the mixture was granulated with a granulator and dried to prepare granules.

Formulation Example 6 (Emulsion) Conidia per 1 g of a mixture of polyoxyethylene nonyl phenyl ether ammonium phosphate 18%, polyoxyethylene nonyl phenyl ether 6%, triethyl phosphate 29% and tributyl phosphate 47% JT-1008) 10
^Eight emulsions were added and suspended uniformly to prepare an emulsion.

Formulation Example 7 (Oil) Conidium (JT-1008 strain) 10 in 1 ml of a mixture of 95% spindle oil, 4% castor oil and 1% silicone oil
^Eight were suspended and the oil agent was adjusted.

[0035] Formulation Example 8 (Dry flowable formulation) 12% sodium alkylbenzene sulfonate, conidia in polyethylene glycol ether 88% of the composition 1 ml (JT-1006 strain) was suspended 10 ^8, adjusting the dry flowable formulation did.

Formulation Example 9 (Capsule) 10 ⁸ conidia (JT-1007 strain) were placed in 1 ml of a mixture of 0.7% sodium alginate, 5% kaolin, 15% glycerin, and 79.3% water. The suspension was suspended and dropped into a 0.2 molar calcium acetate solution to obtain a capsule-like product. After chopping this, it was sieved and air-dried to prepare a capsule.

[0037]

EFFECTS OF THE INVENTION The herbicide of the present invention can selectively kill or inhibit the growth of the genus Firefly in the family Cyperaceae, and can control it without affecting crops such as rice. Also,
It does not pollute or destroy the environment unlike chemical pesticides.

Claims (5)

[Claims] 1. A strain belonging to the genus Ascokita, which is pathogenic to any of the firefly, fireflies, taiwanyamai, or the genus firefly. 2. A strain belonging to the genus Ascokita, wherein the strain is Ascokita sp.JT-1006, Ascokita sp.JT-1007, or Ascokita.
The strain according to claim 1, wherein the strain is sp.JT-1008 strain, Ascokita sp.JT-1009 strain, or Ascokita sp.JT-1010 strain. 3. A herbicide comprising, as an active ingredient, a strain belonging to the genus Ascokita, which is pathogenic to any of the firefly, fireflies, taiwanyamai, and the genus firefly. 4. A strain belonging to the genus Ascokita, wherein the strain is Ascokita sp. JT-1006, Ascokita sp.
The herbicide according to claim 3, which is sp.JT-1008 strain, Ascokita sp.JT-1009 strain, or Ascokita sp.JT-1010 strain. 5. A method for controlling weeds using the herbicide according to claim 3 or 4.