JPH06305927A - Controlling method for black rot - Google Patents

Abstract

PURPOSE:To effectively prevent black rot, one of principal plant bacterial diseases having been difficult to control without any injury from phytotoxicity. CONSTITUTION:Non-pathogenic Erwinia cartovora, preferably Erwinia cartovora- CGE234M403 strain (FERM-P-11792) is applied to a soil or crops to prevent black rot. As a method for preparing Erwinia cartovora bacteria, it is preferable to pick up a large number of bacteria belonging to Erwinia, soft rot bacteria, from vegetables having soft rot maculae or being healthy, which are treated to mutate by a mutating agent (e.g. ethylmethanesulfonyl nitrosoguanidine) or UV rays, then pick up strains having depressed pectinase secretion activity and select strains having especially high lesion inhibiting activity by a pathogenic test using sliced Chinese cabbages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling black rot by applying bacteria belonging to the scientific name Erwinia carotovora to soil or crops alive.

[0002]

[Prior Art and Problems] Xanthomonas, Campestris, Passover, Campestris
onas campestris pv. campe
The black rot caused by the stris) occurs in cruciferous crops such as cabbage, Japanese radish, broccoli, Chinese cabbage, and the damage is great.

At present, as a method for controlling black rot,
For chemical control, copper wettable powder, organic copper wettable powder, kasugamycin / copper wettable powder, nonylphenolsulfonic acid copper wettable powder,
Copper / vinclozolin wettable powder and probenazole granules are used as a preventive spray immediately after planting.
However, these drugs are not sufficiently effective, and the emergence of resistant bacteria, environmental pollution, and further phytotoxicity have become problems, making it highly safe and pesticide-free. Development is desired.

[0004]

[Means for Solving the Problems] As a result of intensive studies, the present inventors have found that a microbial pesticide formulation containing a non-pathogenic soft rot fungus effective for controlling soft rot as an active ingredient is applied to soil or crops. They have found that black rot can be effectively controlled and have reached the present invention. That is, the present invention is
A control agent for black rot characterized by containing pathogenic deficient Erwinia carotovora bacteria as an active ingredient, and applying pathogenic deficient Erwinia carotovora bacteria to soil or crops. Is a method for controlling black rot. Furthermore, the agent for controlling black rot and the method for controlling the same are characterized in that the pathogenic deficient Erwinia carotovora bacterium is Erwinia carotovora CGE234M403 strain.

The Erwinia carotovora bacterium is a bacterium that causes a so-called soft rot that causes softening and decay of storage tissues of many plants such as Chinese cabbage, Japanese radish, and the like, and it has been reported to exist in soil unbiasedly. Occurrence of soft rot is sometimes observed even in fields that have not produced crops that host this fungus for more than 5 years. The ecology of this bacterium is thought to be as follows (Hiroyuki Tsuyama, Plant Protection No. 34
Vol. 294-298 (1980). For example, in the case of Chinese cabbage, after sowing, this bacterium grows around the roots about 40 days after the seeding, and the presence of the bacterium can be recognized in almost all places such as rhizosphere soil and leaves. Then, if the Chinese cabbage is damaged by typhoons, insects, or daily work, bacteria will invade from it, and if the climatic conditions are adjusted, the concentration of pathogenic bacteria will rise overnight, and lesions will become visible. Therefore, to prevent these diseases, if it becomes possible to grow non-pathogenic Erwinia carotovora bacteria instead of pathogenic bacteria in root soil and leaves in the same manner as the pathogenic strain, It can be expected that the soft rot can be controlled by suppressing the growth of bacterial strains, and as a result of diligent studies under the consideration by the present inventors, among the mutant-treated strains of Erwinia carotovora bacteria, pathogenicity is shown. Of strains that have good pathogenicity and competent with the same bacteria that have no pathogenicity are selected, and live strains of Erwinia carotovora bacteria lacking these pathogenicities are selected from soft rot disease-affected plants. It was found that soft rot can be effectively controlled by inoculating the roots or leaves, and a patent application was filed (JP-A-3-10).
1606, JP-A-4-179475).

[0006] Next, Erwinia deficient in this pathogenicity
A method for producing carotovora bacteria is described. The present inventors collected a large number of Erwinia bacteria from vegetables having soft rot spots or healthy vegetables. Erwinia carotovora bacteria lacking pathogenicity were created by mutating these soft rot fungi. As the mutagenesis method, generally used mutagenesis agents, for example, methods using ethylmethanesulfonyl, nitrosoguanidine, etc. and ultraviolet rays (Microbiology Experimental Method, Microbial Research Method Roundtable pp. 288-306)
Kodansha 1982, or Microbial Genetics Experimental Method, edited by Tatsuo Ishikawa, pp. 3-32, Kyoritsu Shuppan 1982, is known, and treatment may be carried out in accordance with these.

[0007] By the way, it is said that the main cause of the pathogenicity of Erwinia carotovora is pectinase secreted by this bacterium, especially pectate lyase (Masato Goto, New Plant Bacteriology, p. 166, Soft Science). 1981). Therefore, screening of pathogenic deletion strains was carried out by picking up strains with reduced pectinase secretion ability and conducting a pathogenicity test using Chinese cabbage slices. The pathogenicity test was carried out by scratching a leaf piece of Chinese cabbage, applying a high concentration of the test bacterial solution, leaving it in a constant temperature bath at 28 ° C. for 24 hours in the presence of water, and then measuring the lesion length. .

The pathogenic deletion strain of the Erwinia carotovora bacterium thus obtained was mixed with the pathogenic strain and inoculated into a scratched Chinese cabbage slice, and the growth of the pathogenic strain was suppressed to cause lesions. Strains were obtained that either did not, or significantly reduced the lesion formation rate. From these pathogenic deletion strains, a strain with a particularly high lesion-blocking ability was selected and deposited at the Institute of Biotechnology, Institute of Biotechnology, and assigned the following deposit numbers.

Erwinia carotovora Subspico carotovora CGE6M14 Microtechnical Research Institute No. 10998 (FERM P-1099
8) Erwinia Carotovora Subspico Carotovora
CGE6M16 Microtech Lab. No. 10999 (FERM P-1099
9) Erwinia Carotobora Subspico Carotobora
CGE10M2 Microtechnology Research Institute, Microbiology No. 11000 (FERM P-1100
0) Erwinia Carotobora Subspico Carotobora
CGE11M5 Microtech Lab. No. 11001 (FERM P-1100
1) Erwinia Carotovora Subspico Carotovora
CGE234M403 Microtech Lab. No. 11792 (FERM P-1179)
2) The present invention uses Erwinia carotovora bacteria in which these pathogenicities have been deleted, and more preferably CGE234M403 strain (FERM P-1179).
2).

Next, a method for preparing the microbial pesticide of the present invention will be illustrated. First, the main component, Erwinia carotovora, is cultured in an appropriate medium. Specifically, for example, 1L
After pre-culturing in the broth medium, the scale is increased to 4 L and the culture is performed for about 20 hours by a jar fermenter.
After completion of the culture, the cells are collected by centrifugation with a centrifuge.

Next, the collected bacterial cells are suspended in a protective solution. Specifically, for example, 40% (w / w) sucrose,
Suspend in a protective solution of 0.1 M phosphate buffer (pH 7.0) with or without 2% (w / w) sodium glutamate. The suspension is frozen and then dried by a freeze dryer. When used as a wettable powder, chemically synthesized water-soluble polymer compounds such as polyvinyl alcohol and polyethylene glycol, polysaccharides such as chitin, chitosan, agar and gum arabic, or proteins such as gelatin are added to the dried cells. Can be mixed.

Further, if necessary, a diluent, an auxiliary agent, etc. are added and mixed to prepare a preparation. The dosage form at this time may be a commonly used dosage form such as powder, granules, suspension, etc., and may be appropriately selected according to the purpose. Examples of the diluent include diatomaceous earth, talc, clay, acid clay, bentonite, kaolin, wood powder, tab powder, lees powder, calcium carbonate, water, and the like, and only one of these may be used. Of course, two or more types can be used in combination.

Specific examples of the auxiliaries include surfactants, stabilizers, and other potentiating agents for increasing the potency of the active ingredient. Of course, only one of these may be used, and two or more of them may be used. These can also be used in combination. The microbial pesticide of the present invention is prepared as described above. At this time, the bacterial density in the preparation is about 1 × 10 ⁶ to 1 × 10 ¹¹ cfu / g in the case of powder and granules, and
When the wettable powder is used by dissolving it in water, it is 1 × 10 ⁶ to 1
It is preferably prepared so as to be about 10 ⁹ cfu / ml.

Next, a method for using the microbial pesticide of the present invention will be described. In order to use the microbial pesticide of the present invention in crops such as cabbage, Japanese radish, Chinese cabbage, broccoli, etc. that cause black rot, it may be used in the same manner as general pesticides. That is, it may be applied in the form of powder or granules to a crop causing black rot, and in the case of a wettable powder, it may be dissolved in a predetermined amount of water and sprayed once to several times. It can also be sprayed preventively immediately after planting.

The amount of the drug to be sprayed is about 100 to 50 kg per 10 ares in the case of powders and granules, and about 100 ml to 400 L per 10 ares when the wettable powder is dissolved in water and used. Is preferred.

[0016]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. Example 1 Erwinia carotovora CGE234 in broth medium
Strain M403 [Ministry of Industrial Research, No. 11792 (FERM
P-11792) has been deposited]
It was cultured at 0 ° C. for 15 hours. The culture solution was collected by using a centrifuge, and the cell concentrated solution (bacteria number 3.0 × 10 ¹¹ cfu
/ Ml) was obtained. Then, the same amount of immobilizing agent [40% (w
/ W) Saccharose, 0.1 M sodium phosphate buffer pH 7.0], lyophilized, and then dissolved in water to adjust the bacterial density to 1 × 10 ⁸ cfu / ml. It was created. Similarly, Erwinia carotovora CGE10M2 strain [Microtechnology Research Institute, No. 11000 (F
ERM P-11000) has been deposited].

10 days after planting the cabbage in a pot, Erwinia, Carotobora, Subspi, Carotobora CG
A suspension (bacterial density 1 × 10 ⁸ cfu / ml) of E234M403 strain and CGE10M2 strain was sprayed. Then, on the 7th day, the black rot fungus (CGX2 strain; bacterial density 1 × 10 ⁸
(cfu / ml) was sprayed, and on the 30th day, the disease onset was investigated. The results are shown in Table 1. The control value is 7 each
It was 1.4% and 57.1%.

[0018]

[Table 1] Example 2 Erwinia carotovora CGE234 in broth medium
Strain M403 [Ministry of Industrial Research, No. 11792 (FERM
P-11792) has been deposited]
It was cultured at 0 ° C. for 15 hours. The culture solution was collected by using a centrifuge, and the cell concentrated solution (bacteria number 3.0 × 10 ¹¹ cfu
/ Ml) was obtained. Then, the same amount of immobilizing agent [40% (w
/ W) Saccharose, 0.1 M sodium phosphate buffer pH 7.0], lyophilized, and then dissolved in water to adjust the bacterial density to 1 × 10 ⁸ cfu / ml. It was created.

A suspension of Erwinia carotovora subsp. Carotovora CGE234M403 strain (bacterial density 1 × 10 ⁸ cfu / ml) was sprayed on pot cultivation broccoli 10 days after planting. On the 7th day after spraying, black rot fungus (CGX2 strain; bacterial density 1 × 10 ⁸ cfu / ml) was sprayed. Then, on the 30th day, an onset investigation was conducted. The results are shown in Table 2. The control value was 90.9%.

[0020]

[Table 2]

[0021]

INDUSTRIAL APPLICABILITY According to the present invention, it has become possible to effectively control black rot, which is one of the main plant bacterial diseases which has been difficult to control in the past. The present invention is a method of using living bacteria as a so-called biological control measure, and provides a safe method of controlling black rot without chemical damage.

Claims (4)

[Claims] 1. A control agent for black rot, which comprises Erwinia carotovora bacteria lacking pathogenicity as an active ingredient. 2. The pathogenic deficient Erwinia carotovora bacterium is Erwinia carotovora CGE234M4.
The control agent for black rot according to claim 1, which is strain 03. 3. A method for controlling black rot, which comprises applying an Erwinia carotovora bacterium whose pathogenicity is deleted to soil or a crop. 4. The pathogenic deficient Erwinia carotovora bacterium is Erwinia carotovora CGE234M4.
The method for controlling black rot according to claim 3, which is a strain No. 03.