JPS5924127B2 - Plant disease control agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel pesticidal agent that can accurately control plant diseases caused by bacteria.

Traditionally, vegetables such as cucumbers, tomatoes, and eggplants 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. Ta.

In particular, these 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 being in a greenhouse, especially under conditions of excessive humidity, the seeds are susceptible to diseases (and as a result, they suffer a great deal of damage, resulting in reduced yields and poor quality).

Traditionally, the main diseases of cucumbers, etc., include powdery mildew, late blight, scab, scab, downy mildew, and gray mold, and many control agents have been developed for these diseases. It is actually 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, cucumber spot bacterial disease is a highly contagious disease that spreads throughout the greenhouse in a very short period of time after its occurrence in a greenhouse with moderate temperature and humidity.

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.

As a method of controlling this, first, disinfection is performed at the seed stage, and then a chemical is sprayed early after germination, but disinfection must be achieved through a combination of these methods.

The one currently considered effective against headquarters was treated with a mercury agent as a disinfectant at the seed stage, but this is currently prohibited from a sanitary standpoint.

In the United States, methods such as immersion in a 1000 times stronger solution (15 to 20°C) for 5 minutes, immersion in boiling water at 50 to 100°C, and immersion in streptomycin agent have been proposed, but these methods are still insufficiently effective. cannot be obtained.

In addition, as a dispersing agent, a hydrating powder mainly containing basic inorganic acid silver, 4-4 lime Bordeaux solution, Bordeaux solution for stomy application, and stomy/terramycin mixed solution can be sprayed every 5 to 7 days. It is said that this effect is expected.

However, since these chemical agents are used at high concentrations, they tend to react and cause chemical damage to leafy greens, so it is necessary to lower the concentration used, and at present there are few that can be expected to provide accurate control. Even if they appear to be temporarily 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 aim of developing bacterial disease control agents, and found that negamycin was highly effective against these bacterial diseases. It has also been found that by using an organic copper fungicide or kasugamycin as an active ingredient, the control effect can be synergistically exhibited.

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 plant pathogenic bacteria that are the subject of the invention.

Examples of inorganic copper fungicides or organic copper fungicides used in the present invention include basic copper chloride, basic copper sulfate, cupric hydroxide, and copper 8-oxyquinoline; Similar effects are expected when used.

Examples of organic fungicides include streptomycin and kasugamycin.

As mentioned above, copper agents may cause chemical damage at high concentrations, while sufficient effects cannot be expected at low concentrations.

Streptomycin is said to be effective when sprayed at a relatively high concentration, but it cannot be expected to be effective in severe outbreaks.

However, when these compounds are mixed with negamycin, their effects appear synergistically, and they exhibit extremely high control effects even when applied prophylactically or therapeutically as a seed disinfectant or as a spraying agent.

The concentration of negamycin used in the present invention is usually 10 to 1
The amount of inorganic or organic copper fungicide added to negamycin is usually 25 to 80 parts by weight per 1 part of negamycin, and the antibiotic agent is 1 to 0 parts by weight per 1 part of negamycin. , 5 parts by weight may be added.

Furthermore, the mixture ratio can be appropriately selected depending on the formulation used, and the mixture can be diluted with an appropriate diluent to obtain a desired concentration.

Negamycin was investigated by the agar dilution method using agricultural research medium and was found to be a fungus that causes bacterial spotting on cucumbers (Pseudomonas lachrymans).
) 6.25-12.5mcg/ml! , Pseudomonas glumae 6.2
5 mcg 7 ml or less, Pseud
omonas mori) 25 mcg/ml,
) Pseudomonas sol
ancearum) 50 mcg/ml and 50 mcg/W of Streptomyces spp.
6.25mCg/ml
Complete inhibition at ~12.5 mcg/ml.

The pesticidal agent of the present invention can be mixed with an appropriate carrier by a known method generally used for agricultural chemicals to form a preparation in the form of a powder, wettable powder, emulsion, liquid, or granule.

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,
Examples of the carrier include silica, diatomaceous earth, and calcium carbonate. Examples of the liquid carrier include water and methanol.

Further examples of auxiliary agents include nonionic anionic surfactants and cationic surfactants, such as alkylaryl polyethylene glycol ethers, alkylaryl sorbitan monolaurates, alkylaryl sulfonates, higher alcohol sulfates, and alkyldimethylbenzylammonium. Halides, etc. are used, and other materials such as lignin 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
When cucumbers (variety Natsusagi Ochi No. 3) grown at a ratio of one plant per 12C1rL flower pot reached the 3-leaf stage, a chemical solution with a predetermined concentration was sprayed with a sprayer over 100 m at a rate of l/7i.

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 inoculated by spraying, kept in a humid room for 48 hours, and then left in a greenhouse. .

The test was carried out in three consecutive trials in one section, and the degree of disease onset and degree of drug damage during the 8 days after inoculation were expressed using the following index, and the degree of morbidity was calculated using the following formula.

Survey index FX8 + EX5 + DX3 + CX2 + BX1 + AXO morbidity -

Note that the concentration of the antibiotic was expressed in ppm, and the concentration of the copper agent was expressed in ppm as copper.

The therapeutic efficacy test was conducted when cucumbers (cultivar Natsusagi Ochi No. 3) grown in a 12CrI'L flowerpot reached the 3-leaf stage. The plants were inoculated by spraying at a rate of 100 m/m'' and kept in a humid room for 488 hours, after which a chemical solution of a predetermined concentration was sprayed at a rate of 100 m/m and left in a greenhouse.

The degree of growth and the degree of drug damage were investigated for 8 days 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 cucumbers (variety Natsaki Ochi No. 3) that have reached the leaf stage were fully planted, and 106 cucumbers/TLl were planted twice, 7 days later and 17 days later.
inoculated with a bacterial suspension of 100 ml/m” (sprayed),
At the same time, diseased leaves were left in the furrows to encourage natural disease development.

From 5 days after planting, apply 2 ooml of the drug at the specified concentration at 7-plant intervals.
Sprayed three times with a shoulder sprayer at a distance of 1 m.

The investigation was conducted two weeks after the final application of the chemical, and the severity of disease was investigated using the same method as in the pot test for every other 5 plants from each district.

The test results are shown in Table 3.

Example 4 As a test method for seed disinfection effect against cucumber spot bacterial disease, cucumber seeds (cultivar Natsu Sairochi No. 3) was inoculated by boxwood vacuum induction (vacuum treatment for 1 hour).

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

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

The number of seeds sown was 5 seeds per pot, and each section 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 containing as active ingredients negamycin or its salts and at least one selected from inorganic or organic copper fungicides and organic fungicides.