JP2732905B2 - Disease control microorganisms of cucumber crops and disease control methods - Google Patents

Description

The present invention relates to a novel microorganism effective for controlling diseases of Cucurbitaceae crops, particularly soil-borne diseases, and a method for controlling diseases using the microorganisms and / or metabolites thereof. About.

[Conventional technology]

The major diseases of cucumber crops are cucumber vine disease,
Cucumber downy mildew, cucumber mosaic disease, melon wilt, melon downy wilt, watermelon wilt, watermelon anthracnose, pumpkin vine blight, pumpkin powdery mildew, etc. Diseases and vine wilt are considered to be difficult to control by soil-borne diseases.

In the disease control method for cucurbits, fungicides are sprayed on foliage for airborne diseases such as downy mildew, but it is effective for soilborne diseases such as vine disease. No fungicide,
In addition to soil disinfection with fumigants and steam, use of resistant varieties or rootstocks, rotation, etc. are being carried out. However, pest control with chemical synthetic pesticides may cause the emergence of drug-resistant bacteria, phytotoxicity, and pollution, and in particular, fumigants such as chloropicrin and methyl bromide indiscriminately kill microorganisms that inhabit the soil, There is the problem of killing even microorganisms that have a beneficial effect on production, and the risk to crops and livestock is extremely high. On the other hand, pest control using resistant varieties or rootstocks has a problem in that parasites of pathogenic bacteria are differentiated, and a pathogenic fungal race that can invade resistant plants appears, and its use is limited. Also,
In recent vegetable cultivation, with the spread of facilities and the designation of production areas, there is a tendency that a single crop is cultivated, and it is difficult to carry out rotation, and the problem of obstacles to continuous cropping is increasing.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned disadvantages in the conventional disease control of cucurbit crops and to provide a new control material that replaces synthetic pesticides. That is,
An object of the present invention is to provide a means for controlling diseases of cucurbit crops, especially soil infectious diseases, which are difficult to control diseases, using a novel microorganism.

[Means for solving the problem]

The present inventors have paid attention to the phenomenon of mutual induction between microorganisms and plants, called "resistance induction". The purpose of the present inventors is to impart disease resistance to crops using microorganisms and to control soil infectious diseases that are difficult to control. As a result of purifying a large number of microorganisms purely and conducting research on cucumber as a main target, they found effective microorganisms not only for cucumber but also for disease control of cucumber crops widely, and also found safe microorganisms for humans, livestock and crops, and completed the present invention. I have reached.

That is, the present invention provides a novel microorganism, Fusarium oxysporum, which is effective for controlling diseases of cucurbit crops.
sporum) MT-3013 (Nippon Kenkyu No. 10787), a method for controlling diseases of Cucurbitaceae crops, which comprises treating the microorganism and / or a metabolite thereof on plant roots or soil.

The microorganism according to the present invention is a novel strain of Fusarium oxysporum sp. Isolated from the rhizosphere of cucumber grown on natural field soil.

Fusarium oxysporu species
m) is defined as having the lowest risk according to the National Institute of Health's Regulations on the Control of Pathogens, etc., "1; there is almost no possibility of laboratory infection, even when handling large quantities." Is guaranteed, as is this strain.

The culture of the microorganism according to the present invention can be easily performed by shaking culture or stationary culture using a liquid medium for filamentous fungi such as a liquid culture medium of Tupec, potato dextrose, or the like. Culture in a solid medium such as a medium is also effective. In addition, it is possible to culture a large amount by culturing using a jar fermenter or soil bran culturing.

The treatment method according to the present invention is carried out on the root of a crop or a cultivated soil, and the treatment form is not only the spores but also the mycelium containing mycelium, and the metabolism of the culture filtrate, spore germination liquid and the like of the microorganism. The product is also effective.

The treatment of the plant root is carried out by immersing the root in a spore or mycelium suspension, a culture filtrate, or a spore germination solution, and the treatment of the soil is carried out by irrigation or crop application.

The treatment time is preferably both during seedling raising and during planting, and additional application during cultivation in this field is effective in maintaining the control effect.

Incidentally, suspension 1ml per spore 10 ⁴ or more in the case of Hitane treatment, preferably at ¹⁰⁶ or more, in the case of soil treatment dry soil 1g
Per 10 ³ or more, preferably it is observed a sufficient control effect at 10 ⁵ or more.

In addition, by using the control method according to the present invention in combination with other control methods such as the use of resistant varieties, the present invention is also effective in disease-prone soils with an increased pathogenic bacterial density, such as continuous crop fields.

[Action]

The microorganisms and the method for controlling disease according to the present invention are extremely effective for controlling vine wilt, seedling blight, powdery mildew, etc. in the case of cucumber, and vine wilt, vine blight, powdery mildew in the case of melon. It is effective for pest control. The same applies to other cucurbit crops such as watermelon and pumpkin, and is effective in controlling similar diseases.

〔Example〕

Hereinafter, the novel microorganism according to the present invention and a method for controlling a disease using the microorganism and / or a metabolite thereof will be described in detail with reference to examples.

The microorganism according to the present invention is a novel strain obtained by separating from the rhizosphere of a cucumber grown in a natural field soil, and is specified as follows.

Fusarium spp. Is identified as Oxysporum spp. Because it forms small conidiospores in the form of pseudoheads on short basidiomycetes in a filamentous fungus medium such as Tuapec agar medium.

It is not pathogenic to cucumber and other cucumber crops and other useful crops.

Example 1 Separation Method of New Microorganism Roots of cucumber growing on natural soil in a field were collected. Roots were prepared by cutting slices 5 to 10 mm in length, immersed in 70% aqueous ethanol for 2 to 3 seconds, and then immersed in 2% aqueous sodium hypochlorite for 10 minutes.
Root sections were surface sterilized. After washing with sterile water, agar 1.5%
The plate was placed on a nutrient-free plate medium, and cultured in a thermostat at 25 ° C. for 72 to 120 hours. Microorganisms emerging from the plant tissue were isolated by single hypha separation under a stereoscopic microscope.
The resulting microorganisms are tested for their control effect against cucumber wilt, and further tested for their pathogenicity to other crops.
A novel microorganism, MT-3013, which has a controlling effect on cucumber wilt and has no pathogenic effect on other crops was isolated.

Example 2 Identification of a novel microorganism The microorganism according to the present invention was identified by culturing the microorganism on a PS (potato sucrose) agar medium. As a result, MT-3013 reaches a colony diameter of 6 to 7 cm at 25 ° C. for 4 days. Large numbers of large conidia, small conidia and chlamydospores are formed. Large conidiospores are crescent-shaped, small conidiospores are cylindrical to long elliptical,
Chlamydospores are spherical. None of the spores are formed in a chain. When cultured in the dark, purple pigment acid is observed. From these characteristics, MT-3013 was determined to be Fusarium oxysporum.

Example 3 Physiological properties of novel microorganisms The microorganisms according to the invention are aerobic and viable
The pH is 3 to 10 and the temperature is 5 to 35 ° C, but the optimal pH is 6 to 8 and the optimal temperature is 25 to 30 ° C.

Example 4 Mass cultivation method of novel microorganism The microorganism according to the present invention can be easily cultured in an inexpensive culture medium such as PS (potato sucrose) or MS (mash potato sucrose) medium. By performing liquid culture in a mentor for 72 hours, 100 million spores were obtained per 1 ml of the culture solution. As described above, the microorganism of the present invention can be used industrially because large-scale culture can be efficiently performed.

Test Example 1 Ten cucumber seedlings (cultivar: Shimochi Shizenji) having two to three true leaves grown on vermiculite were tested per experimental plot. The microorganism of the present invention, 27 ° C. in potato dextrose liquid medium, the spores obtained by shaking culture for 6 days, the dilution adjusted suspension 10 ⁷ cells / ml with sterile distilled water, the cucumber seedlings After soaking the roots for 30 minutes, they were provisionally planted in vermiculite. As a control, cucumber seedlings were treated in sterile distilled water in the same manner, and then temporarily planted in vermiculite. 36 hours later, in potato dextrose broth 27
Spores obtained by shaking culture at 6 ° C for 6 days,
Fusarari fungus (Fusari) obtained by adjusting the dilution with sterile distilled water
spore suspension of um oxysporum f.sp.cucumerinum) 10 ⁷ / m
The seedlings were immersed again for 30 minutes, planted and cultivated in 1000 ml of the nursery bed soil. After 30 days, observe the onset of the disease,
Each leaf position of the true leaves was expressed as a class value.

0; disease-free 1; disease in a part of the leaf (yellowing, wilt) 2; disease in about 1/2 of the leaf 3; disease in most of the leaves or defoliation The disease index was determined. Furthermore, the control rate by inoculating this strain with roots was calculated by the following formula with respect to the average disease index of the control group.

As shown in Table 1, the spore suspension of the microorganism of the present invention was applied to the roots of cucumber, whereby the disease index of vine disease was significantly reduced as compared with the control, and an extremely high control rate was obtained. Was done.

Test Example 2 Cucumber seeds (cultivar: Shimochijiro) were sown and seeded in 100 ml of a nursery bed in which 10 ⁵ spores / g of the microorganism of the present invention obtained by the same method as in Test Example 1 survived. 10 per experiment
Individuals were tested. As a control, a seedling similarly raised on sterile seedling bed soil was used. After the true leaves were planted in 1000 ml of the nursery bed soil in the third to fourth stages, respectively, the vines (Fusarium oxysporum f.sp.cucu) obtained in the same manner as in Test Example 1 were obtained.
10 ml of a spore suspension of S. merinum) was irrigated and inoculated into each strain. The disease state was observed 50 days later, the average disease index was determined in the same manner as in Test Example 1, and the control rate of the treated group relative to the control group was calculated.

As shown in Table 2, the cucumber seedlings raised on the nursery soil containing the microorganisms of the present invention showed a significantly reduced index of vine disease as compared with the control plot, indicating a high control effect. .

Test Example 3 Ten cucumber seedlings (cultivar: Shimochi Fujichikugo) of the 2 to 3 leaf stage grown on vermiculite were tested per experimental plot. Cucumber seedlings, 27 ° C. in Tsuapekku liquid medium 6 days with shaking microorganism culture filtrate of the culture, sterile filtered present invention obtained by following or spores 10 ⁷ cells / ml containing Tsuapekku liquid of the microorganism of the present invention, The medium was shake-cultured at 27 ° C. for 12 hours to germinate spores, immersed in a spore germination liquid obtained by aseptic filtration for 30 minutes, and then temporarily planted in vermiculite. As a control, cucumber seedlings were treated in sterile distilled water in the same manner, and then temporarily planted in vermiculite. 36 hours later, it was immersed again in a spore suspension of Fusarium oxysporum f.sp. cucumerinum obtained in the same manner as in Test Example 1 for 30 minutes, and each was planted and cultivated on 1,000 ml of nursery soil. . After 20 days, the onset condition was observed, and Test Example 1 was used.
The average disease index was determined in the same manner as described above, and the control rate of the treated group relative to the control group was calculated.

As shown in Table 3, by treating the culture filtrate and spore germination liquid of the microorganism of the present invention on cucumber roots, the disease index of vine disease was reduced as compared with the control, and a high control rate was obtained. Was.

Test Example 4 Melon seedlings (variety: ARS Tokai R-250) with 3 to 4 true leaves grown on vermiculite were grown at 10 per experimental plot.
Individually tested. After immersing the melon seedlings in the spore suspension of the microorganism of the present invention obtained in the same manner as in Test Example 1, for 30 minutes,
Each plant was temporarily planted in vermiculite. As a control, melon seedlings were treated in sterile distilled water in the same manner, and then temporarily planted in vermiculite. 36 hours later, Fusarium oxysporum f.sp.meloni obtained by the same method as in Test Example 1.
s) Soak again in the spore suspension for 30 minutes, and raise the seedling bed soil 1000 ml
Were planted and cultivated. After 30 days, the disease was observed,
The average disease index was determined in the same manner as in Test Example 1, and the control rate of the treated group relative to the control group was calculated.

As shown in Table 4, treatment of melon root with the spore suspension of the microorganism of the present invention significantly reduced the disease index of vine disease compared to the control group, resulting in an extremely high control rate. Was done.

Test Example 5 Melon seeds (variety: ARS Tokai R) were added to 100 ml of the nursery soil containing the microorganism of the present invention obtained in the same manner as in Test Example 2.
-250) were sowed and raised, and 10 individuals were tested per experimental plot. As a control, a seedling similarly raised on sterile seedling bed soil was used. The nursery bed soil 1000ml in the 4th to 5th leaf stage
, And 10 ml of a spore suspension of Fusarium oxysporum f.sp.melonis obtained in the same manner as in Test Example 1 was irrigated and inoculated into each strain base and cultivated. The disease state was observed 50 days later, the average disease index was determined in the same manner as in Test Example 1, and the control rate of the treated group relative to the control group was calculated.

As shown in Table 5, the melon seedlings bred on the nursery soil containing the microorganism of the present invention showed a significantly reduced vine disease development index compared to the control group, indicating a high control effect.

Test Example 6 Cucumbers (cultivar: Shimochi-no-Hidori) were sown and raised in 500 ml of the nursery soil containing the microorganism of the present invention obtained in the same manner as in Test Example 2, and 5 individuals were tested per experimental plot. did. In addition,
As a control, a seedling similarly raised on sterile nursery soil was used. The true leaves were planted in the 7th to 8th cropping season field where vine disease was severely infested. At this time, the nursery bed soil containing the microorganism of the present invention obtained in the same manner as in Test Example 2 was added to a 1/10 volume planting hole of the cultivated soil. In addition, a soil which had been sterilized by injecting a 1000-fold solution of benomyl agent [benrate wettable powder (trade name, manufactured by Dupont)] into the soil which caused the wilt disease was also tested. After 60 days, the disease state was monitored, the average disease index was determined in the same manner as in Test Example 1, and the control rate of the treated section relative to the control section was calculated.

As shown in Table 6, by treating the microorganism of the present invention at the time of raising seedlings and at the time of planting, a control effect equal to or higher than that of the benomyl agent was obtained.

Test Example 7 Five young seedlings of eggplant (variety: Senryo No. 2), tomato (variety: Ponderosa), strawberry (variety: Hokko Kosei), and radish (variety: Wakakoma) were tested per experimental plot. The spore suspension of the microorganism of the present invention obtained in the same manner as in Test Example 1 was immersed in a spore suspension for 30 minutes, and planted and cultivated in 1000 ml of the nursery soil. As a control, Fusarium oxysporum which is pathogenic to each crop obtained by the same method as in Example 1 (Fusarium oxysporum)
f.sp.melongenae), Fusarium oxysp.
orum f.sp. lycopersici race J-1), spore suspension of strawberry yellow blight (Fusarium oxysporum f. sp. fragariae), and radish yellow rot (Fusarium oxysporum f. sp. did. After 30 days, the onset of the disease was monitored and judged based on external symptoms such as growth inhibition, leaf yellowing, and withering.

As shown in Table 7, this microorganism showed no pathogenicity to cucurbit crops, eggplants, tomatoes, strawberries, and radish.

〔The invention's effect〕

Fusarium oxysporum MT-3013, a new microorganism according to the present invention
No. 7) is the disease of cucumber and other cucumber crops,
In particular, it is effective for controlling soil infectious diseases, which are difficult to control, and is selected from microorganisms that inhabit the natural world. .

Claims (2)

(57) [Claims] 1. A novel microorganism Fusarium oxysporum MT which is effective for controlling disease of cucurbit crops
-3013 (Microtechnical Laboratory No. 10787). 2. A novel microorganism, Fusarium oxysporum MT-3013 (Microorganisms No. 1078).
7) A method for controlling disease of Cucurbitaceae crops, which comprises treating and / or metabolites thereof on plant roots or soil.