JPH092911A - Bacterial wilt controlling agent - Google Patents

Abstract

PURPOSE: To obtain at low cost an agent high in inhibitory effect on bacterial wilt, having no adverse effect on the environment even after repeatedly applied, by combining crab crust with one or two kinds of specific substance. CONSTITUTION: This bacterial wilt controlling agent is a combination of crab crust with Bacillus cereus and/or Bacillus subtilis. This agent is obtained by the following method: crab crust is ground, in advance, into pieces <=5 (pref. 1-5)mm in size which are then mixed with the cultured product of Bacillus cereus and/or Bacillus subtilis (the most inexpensive method). In order to further facilitate handling, after mixing, the mixture may be dried at room temperature to 70 deg.C. The cultured product of Bacillus cereus and/or Bacillus subtilis is obtained by aerobically culturing the microbes at 20-45 deg.C in a medium, after adjusted to pH7 or so, containing nutrients such as meat extract, peptone, yeast extract, starch, glucose, sucrose, potassium phosphate and/or magnesium sulfate. For this controlling agent, the above-mentioned mixture at a microbial concentration of >=10<4> CFu/g is applied at a level of >=100kg/10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bacterial wilt control material comprising a mixture of a crab shell and Bacillus cereus and / or Bacillus subtilis.

[0002]

2. Description of the Related Art Cropping of solanaceous crops often causes bacterial wilt by continuous cropping, which causes a great loss to farmers.

[0003] Several methods have been tried as a method for controlling bacterial wilt. For example, the method includes soil sterilization with a drug such as chlorpicrin or methyl bromide. However, soil sterilization with these agents may indiscriminately kill beneficial soil animals such as beneficial bacteria and earthworms, destroying the composition of soil microorganisms and inducing a disease outbreak caused by bringing in from outside after sterilization. . The reduction of beneficial fungi and soil animals inhibits the healthy growth of crops. In addition, these agents have an irritating odor and are not only costly, but also cause environmental problems such as ozone layer destruction and soil residual contamination due to repeated application.

[0004] As another control method, Pseudomonas solanacearu, a bacterial wilt fungus, is used.
m) The method of applying compost prepared from livestock dung, sawdust, rice straw, etc. to grow the antagonistic bacteria, and the method of grafting seedlings resistant to disease to increase disease resistance against wilt disease are also available. It is being appreciated. However, the application of compost cannot be expected to have a certain effect, and even in grafting, at present, a rootstock that is not sufficiently effective for the bacterial wilt of Solanaceae has not been developed.
In addition, several methods have been reported for controlling and controlling continuous cropping disorders using microorganisms.

For example, JP-A-61-200193 discloses a rhizosphere soil improving agent using living cells or spores of various microorganisms, and crab shells are exemplified as a material for promoting the growth of microorganisms. It does not disclose the present invention described below.
Furthermore, in the Japan Society for Plant Pathology Vol.58 (1992), Masada et al. Reported a method for controlling tomato root rot wilt disease and bacterial wilt disease using Bacillus subtilis. However, in general, when an antagonistic bacterium is used, the survival rate in soil is low, and a sufficient effect is not obtained due to deactivation and the like, so that it has not been put into practical use.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to have a high inhibitory effect against bacterial wilt disease and to be environmentally friendly even when repeatedly applied at low cost. An object is to provide a wilt control agent which has no influence.
We already have Pseudomonas fluorescens (Pseudom
I proposed a material to mix onas fluorescens) and crab shells. However, as a result of further diligent examination, Pseudomonas
The present invention has been completed by finding that it is more effective to use Bacillus cereus and / or Bacillus subtilis instead of fluorescence.

[0007]

That is, the present invention relates to a bacterial wilt controlling material comprising a mixture of crab shell and Bacillus cereus and / or Bacillus subtilis.

The inventors of the present invention have shown that the antagonism of Bacillus cereus and Bacillus subtilis to bacterial wilt disease in v
As a result of itro's examination, antagonisticity was recognized, but even if only these Bacillus cereus and Bacillus subtilis cells are applied to soil contaminated with bacterial wilt, the bacterial wilt of crops can be controlled. I couldn't.

Therefore, the present invention has been completed by studying a method of expressing the antagonistic activity against the bacterial wilt of Bacillus cereus and Bacillus subtilis, which has been observed in vitro, in soil infected with bacterial wilt.

[0010]

The present invention will be described below in detail. As a method for producing the bacterial wilt control material of the present invention, a crab shell of 5 mm or less in advance,
It is the cheapest to crush to 1 to 5 mm, and to mix the culture of Bacillus cereus and / or Bacillus subtilis into the crab shell. After mixing, it may be dried at room temperature to 70 ° C. for easy handling.

Bacillus cereus and / or Bacillus
The culture of subtilis is a medium containing nutrients such as meat extract, peptone, yeast extract, starch, glucose, sucrose, potassium phosphate, magnesium sulfate, etc., and after adjusting the pH to around 7, the temperature is 20-45 ° C. Preferably at 25-35 ° C,
It is produced by aerobically culturing for about 24 hours.

The control material of the present invention is Bacillus cereus and / or
Alternatively, the bacterial concentration of the mixture of Bacillus subtilis and crab shell is preferably 10 ⁴ CFU / g or more from the viewpoint of effect expression.

In the production of the control material of the present invention, it is of course possible to add a carbon source, a nitrogen source, a nutrient source such as potassium phosphate and the like, and it is not possible to add a microbial growth material and soil improving material such as peat moss and vermiculite. It is more preferable in terms of handling and effect.

As a method of using the pesticidal material of the present invention thus prepared, it is desirable to apply it to soil before planting a plant from the viewpoint of manifesting effects. The application rate varies depending on the bacterial concentration of the control material, but generally 100 Kg / 10a or more is preferable. Also,
Alternatively, it can be applied to crops in the early stage of bacterial wilt, but the effect is inferior to that before planting.

Since the control material of the present invention mainly uses natural materials such as antagonistic bacteria and crab shells, it can be handled in the same manner as compost or fertilizer, and even if it is repeatedly applied, it can be used as a pesticide. There is no soil pollution and no harmful effects on humans and animals.

[0016]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. Also,
All percentages are by weight unless otherwise specified.

(Materials used) Bacterial wilt disease --- Pseudomonas solanasirum having the ability to cause bacterial wilt when infected with tomato isolated from the stem of tomato that died due to bacterial wilt. Bacterial wilt fungus culture --- The bacterial wilt fungus of ---- is treated with PPGB medium (potato decoction 1000 ml of 200 g of potato, 5 g of peptone, 5 g of glucose, disodium phosphate 12-hydrate 3
g, monopotassium phosphate 0.5 g, salt 3 g)
Cultivated by a conventional method. Soil contaminated with bacterial wilt disease --- Soil mixed with air-dried Kakogawa alluvial soil and mixed with sterilized water to a water content of 20%. Crab shell--crushed to 5 mm or less. The control material of the present invention 1 ---- Bacillus cereus IFO-3003 is cultured by a conventional method in a meat extract medium (meat extract 10 g, peptone 10 g, yeast extract 2 g, salt 2 g dissolved in water to 1000 ml), This culture mixed with crab shells in various proportions. Inventive control material 2 --- Bacillus subtilis IFO-3009 is cultured by a conventional method in a meat extract medium (meat extract 10 g, peptone 10 g, yeast extract 2 g, salt 2 g dissolved in water to 1000 ml). Then, this culture was mixed with crab shells at various ratios. A mixture of the present invention pesticide 3--. Bacterial wilt detection medium (Original / Ono medium) --- Potato 20
Calcium nitrate tetrahydrate in 1000 ml of potato decoction from 0 g
0.5 g, disodium hydrogen phosphate dodecahydrate 2 g, peptone 5
g, sucrose 15 g, crystal violet 5 mg, cycloheximide 50 mg, polymyxin B sulfate 50 mg, chloramphenicol 10 mg, and 2,3,5 triphenyltetrazolium chloride 25 mg.

125 g of soil contaminated with bacterial wilt of (Example 1)
(100 g by dry weight) was taken in a large petri dish having a diameter of 158 mm, and the materials shown in Table 1 were added and mixed in the proportions shown in Table 2. This soil was cultured at 30 ° C. for 14 days, and the number of bacterial wilts was examined. The results are shown in Table 2. For the detection of bacterial wilt disease, the number of colonies on the second day of culture was counted at 30 ° C. using the Haro-Ono medium.

As is clear from Table 2, the bacterial wilt disease is remarkably reduced when the control material of the present invention is used.

[0021]

[Table 1]

[0022]

[Table 2]

(Example 2) Kakogawa alluvial soil was placed in a large planter (length 65 cm x depth 40 cm x depth 25 cm) in a house (keeping the temperature at 20 ° C or higher at night, 20 to 35 ° C during the day). By repeating the irrigation of the bacterial wilt culture to this planter, the bacterial wilt density became 6.18 × 10 ⁵ CFU / g dry soil. This soil is a heavily contaminated soil that is infected with bacterial wilt in 7 to 10 days if planted tomatoes are cultivated while being kept at a night temperature of 20 ° C or higher.

[0024] The above-mentioned bacterial wilt disease-causing soil (bacterial wilt disease number 6.18 x
10 ⁵ CFU / g dry soil) in a 1 / 5000a pot by dry weight 2 kg, chemical fertilizer (N, P ₂ O ₅ , K ₂ O, containing 10% of each component) 10 g
And 4 g of peat moss were applied. Furthermore, 10 g of various materials shown in Table 3 were added and mixed well. Leave this in a greenhouse (at night temperature 20 ℃ or more, 20-35 ℃ during the day) On the 14th day, plant 4 tomato seedlings (4 seedlings) in this pot, Cultivated in the house for 35 days. The test was carried out in 5 pots for each of the comparative example and the present invention. The results are shown in Table 4.

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

INDUSTRIAL APPLICABILITY The present invention is an excellent and inexpensive pesticidal material which has a high inhibitory effect against bacterial wilt disease and has no effect on environmental pollution even if it is repeatedly applied.

Claims (1)

[Claims] 1. A bacterial wilt control material comprising a mixture of crab shell and Bacillus cereus and / or a mixture of crab shell and Bacillus subtilis.