JPS5823364B2 - Shyokubutsubiyogaiboujibojizai - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel pesticidal agent capable of accurately controlling plant diseases caused by bacteria.

Traditionally, cucumbers, tomatoes, eggplants, and other cucumbers were grown seasonally, but with the recent spread of greenhouse horticulture technology and increased public demand, they have come to be grown year-round regardless of the season. .

In particular, these cane vegetables require appropriate temperature, humidity, and sunshine hours during periods other than their seasonal cultivation, so cultivation in vinyl greenhouses has become mainstream from the viewpoint of cultivation management. .

However, under the limited conditions of a greenhouse, especially under conditions of excessive humidity, various diseases are likely to occur, resulting in extensive damage, resulting in reduced yields and quality.

Traditionally, the main diseases of cucumbers, etc., are powdery mildew, late blight, scab, anthracnose, downy mildew, gray mold, etc., and many control agents have been developed for these diseases and are not currently available. Used for pest control.

However, due to changes in cultivation conditions in recent years, bacterial diseases have become more prevalent, causing great damage.

For example, bacterial spot disease of cucumber is a highly contagious disease, and in a greenhouse with moderate temperature and humidity, it spreads throughout the greenhouse within a very short period of time after its occurrence.

In this case, it is extremely difficult to control with chemicals, so
It poses a major threat to greenhouse cultivation.

It is known that the transmission route of bacterial spot disease of cucumber is mainly through infected seeds.

In particular, when the virus is carried in the seeds, it is transmitted to the cotyledons upon germination, resulting in large, water-soaked lesions that cause damage such as softening and withering of the seedling spots.

The method of controlling this disease is to first disinfect the seed stage, and then spray chemicals early after germination (disinfection must be carried out in combination with these methods).

The seeds that are currently considered effective against serious diseases were treated with mercury as a disinfectant at the seed stage, but this is now prohibited from a sanitary standpoint.

In the United States, methods such as immersion in a 1000 times stronger solution (15 to 20℃) for 5 minutes, immersion in boiling water at 50 to 100℃, and immersion in streptomycin have been proposed, but they still do not have sufficient control effects. I can't do it.

In addition, as a dispersing agent, a hydrating powder mainly containing basic inorganic acid copper, 4-4 lime Bordeaux solution, Bordeaux solution for adding Stomai, and a mixture of Stomai and Terramycin may be sprayed every 5 to 7 days. It is said that this effect is expected.

However, since the concentration of copper used among these drugs is high, it is easy to cause chemical damage to leaf greens in response, so the concentration used must be lowered.Currently, there are few that can be expected to provide appropriate control, and only temporary Even if they appear to be effective, many of them lack long-lasting efficacy.

In view of these current circumstances, the present inventors conducted a variety of studies on many drugs with the goal of developing bacterial disease control agents, and as a result,
We have found that negamycin is highly effective against these bacterial diseases, and that by using an inorganic or organic copper fungicide, kasugamycin, or the like as an active ingredient with negamycin, the controlling effect is exhibited synergistically.

Negamycin, which is the active ingredient of the bacterial disease control agent according to the present invention, is a known antibiotic (see Japanese Patent Publication No. 46-28835) and is known to be effective against Durham-negative bacteria. It is completely unknown that spraying on plants is effective against the target plant pathogenic bacteria.

Negamycin was investigated by agar dilution method using Agricultural Research Medium and found that it was found in cucumbers, Pseudomonas spp.
s lachrymans) 6.25-12.5
mcg/rn & rice blight-causing bacterial pathogen (Pseudomona
s glumae) 6,25 mc g/ml or less, Pseud-omonas monas
r i ) 25 mcg/ml, ) Pseudomonas solancearum
50 mcg/m & Bean Kasa blight 50 mcg/m
The growth of each strain was completely inhibited by using a value of 1, and the potato figrt disease bacterium (S t
6.2 Growth of reptomyces cavies)
Complete inhibition was achieved between 5 mcg/ml and 12.5 mcg/ml.

When the negamycin of the present invention is used as a pesticidal agent, it can be mixed with an appropriate carrier by a known method generally used as an agricultural chemical to form a preparation in the form of a powder, an aqueous solution, an emulsion, a liquid, a granule, or the like.

The carrier used in the present invention may be either solid or liquid as long as it is inert or harmless to the active ingredient.

Examples of solid carriers include talc, clay, kaolin, silica, diatomaceous earth, and calcium carbonate, and examples of liquid carriers include water, methanol, and the like.

Further examples of auxiliary agents include nonionic anionic surfactants and cationic surfactants, such as alkylaryl polyethylene glycol ethers, alkylaryl sorbicune monolaurates, alkylaryl sulfonates, higher alcohol sulfates, and alkyldimethylbenzylammonium. Halides and the like are used, and others such as halogen sulfonate, calcium stearate, polyvinyl alcohol, and carboxymethyl cellulose are used.

Next, the pest control effect of the pest control agent of the present invention will be explained with reference to Examples.

The test method was carried out as follows. The preventive effect test is 1
When cucumbers (variety Natsusagi Ochi No. 3) grown at a ratio of one plant per 2cIrL flower pot reached the 3-leaf stage, a chemical solution with a predetermined concentration was sprayed with a sprayer at a rate of 1001 rLl/m2.

The day after spraying, a bacterial suspension of cucumber spot bacteria cultured at 27°C for 24 hours in a semi-synthetic potato medium was spray-inoculated at a concentration of 109 cells/1 rLl, kept in a humid room for 48 hours, and then placed in a greenhouse. .

The test was conducted in triplicate per section, and the degree of disease onset and drug damage on the 8th day after inoculation was expressed using the following index, and the degree of morbidity was calculated using the following formula.

The investigation results are shown in Table 1 below, and the negamycin of the present invention showed a high pesticidal effect.

The therapeutic efficacy test was conducted when cucumbers (variety Natsusagi Ochi No. 3) grown at a ratio of 1 pot to 1 pot reached the 3-leaf stage.
The plants were inoculated by spraying in an amount of Ll/- and kept in a humid room for 48 hours, and then a chemical solution of a predetermined concentration was sprayed in an amount of 100 ml and 177 FL' and left in a greenhouse.

The degree of growth and the degree of chemical damage were investigated on the 8th day after inoculation, and the degree of morbidity was calculated in the same manner as in the preventive effect test.

Example 1 Cucumber spot bacterial disease prevention efficacy test The test was conducted according to the method described above.

The test results are shown in Table 1.

Example 2 Cucumber spot bacterial disease treatment efficacy test The test was conducted according to the method described above.

The test results are shown in Table 2.

Example 3 As a test method for controlling cucumber spot bacterial disease in a greenhouse, five
10 cucumber plants (cultivar Natsuzaki Ochi No. 3) that have reached the leaf stage were fully planted, and a bacterial suspension of 106 cells/ml was inoculated twice, 7 days later and 17 days later, by spraying at 100 ml/rrj'. At the same time, diseased leaves were left in the furrows to encourage natural disease development.

From 5 days after planting, apply 200ml of the drug at the specified concentration at 7th intervals.
/rrf' was sprayed three times with a shoulder sprayer.

Two weeks after the final application of the chemical, the disease severity was investigated on all leaves of every other 5 plants from each plot using the same method as in the pot test.

The test results are shown in Table 3.

Example 4 As a test method for seed disinfection effect on cucumber spot bacterial disease, cucumber seeds (
The cultivar Natsusairichi No. 3) was attached and vacuum permeation inoculation (vacuum treatment for 1 hour) was carried out.

The artificially inoculated seeds were air-dried and then stored in a refrigerator at 5°C until testing.

Disinfection treatment 2. Soak the above seeds in each chemical solution at a predetermined concentration for 40 minutes (liquid volume ratio 3:1).
The seeds were inoculated onto the soil surface of a 2cIrL clay pot and left in a glass chamber at 25°C.

The number of seeds sown was 5 seeds per pot, and each district was divided into 5 pots.

In all disease outbreak investigations, germination rates and disease onset rates were investigated at the time of first leaf development.

The test results are shown in Table 4.

Claims (1)

[Claims] 1. A plant bacterial disease control agent characterized by containing negamycin or its salts as an active ingredient.