JPS6320403B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to 3,5-dimethyltetrahydro-2H
-1,3,5-thiadiazine-2-thione and 1,
A soil disinfectant characterized by containing one or two of 2-dibromoethane and dichlorodiisopropyl ether as active ingredients, that is, a soil disinfectant for controlling soil diseases harmful to crops and crop parasitic soil nematodes. This is related to. cyst centiyu,
There are many types of plant-parasitic nematodes, such as Negusa nematode and Negusare nematode, and the damage caused by nematodes to agricultural crops has been significant in recent years. These soil nematodes mainly attack the underground parts of plants, significantly impairing the growth, yield, and quality of crops, but the range of crops that are affected by these nematodes is extremely wide, including corn, soybeans, potatoes, and wheat flour. General field crops, vegetables such as tomatoes, eggplants, carrots, kanran, turnips, special crops such as tea and tobacco, mandarin oranges, apples,
Nematodes control a wide range of areas, including fruit trees such as figs, flower petals, and forest trees, making nematode control an extremely important control problem in agriculture. Particularly in recent years, due to the diversification of vegetable cultivation and the spread of greenhouse horticulture, this pest control measure has become even more important. On the other hand, due to the rapid spread of greenhouse horticulture mentioned above and forced continuous cropping, continuous cropping problems in a wide range of crops have become a major issue that needs to be solved. These continuous cropping problems are not limited to simple factors such as single diseases, nematodes, and pests, but also include (1) physical deterioration of the soil, (2)
Many factors are often involved, including interrelationships between crops, (3) soil diseases, (4) soil nematodes and pests, and (5) harmful substances caused by continuous cropping. Moreover, it is a well-known fact that these factors are intricately involved and cause continuous cropping failure. For example, nematodes themselves cause significant damage to crops, but at the same time, there are also cases where nematodes and other pathogens combine to cause disease, or where nematodes spread to pathogens, resulting in mixed infections. Many have been reported. Namely, black rot of burdock, hanging disease of Japanese cucumber, rot of tomato, damping-off of beet, white silk disease of konnyaku, black rot of radish, and fungal diseases such as konnyaku. Cases have been reported in which such complex factors are considered to be responsible for bacterial diseases such as corm rot in wheat, and viral diseases such as wheat wilt. As can be seen in the close relationship between nematode damage and soil disease mentioned above, it is a comprehensive soil that is effective against a wide range of uses, including not only single soil diseases and nematodes, but also soil diseases, nematodes, soil pests, and weeds. This is why disinfectants are required. 3,5-dimethyltetrahydro- according to the present invention
2H-1,3,5-thiadiazine-2-thione (hereinafter referred to as TMTT) is a compound conventionally known as a soil disinfectant.
It is known to be effective in controlling a wide range of soil diseases and various nematode diseases, such as yellowing of strawberries, late blight of vegetables and tobacco, leaf blight of fruit trees, and damping-off of vegetables. When applied to soil, TMTT quickly hydrolyzes when there is appropriate soil moisture and soil temperature, generating gas that is effective against soil pathogens and nematodes, and exhibits bactericidal, insecticidal, and herbicidal effects. Because of this, it is formulated into fine granules and powder and is widely used as a soil disinfectant. As mentioned above, TMTT's action characteristics include that it begins to gasify immediately after treatment, but its vapor pressure is low, and the effect lasts for a long time, giving it a sufficient effect. However, in order for TMTT to exhibit sufficient effects, it requires a large dose of 20 to 30 kg of active ingredient per 10 ares, which is a practical drawback in that it lacks economic efficiency. In addition, if the effective gas decomposed in the soil comes into direct contact with and absorbed by plant roots, it will cause severe phytotoxicity, so in fields where TMTT is used, sufficient degassing must be done to ensure that the gas does not remain in the soil. There is a problem called. The active ingredients, 1,2-dibromoethane (hereinafter referred to as EDB) and dichlordiisopropyl ether (hereinafter referred to as DCIP), are well-known compounds that are effective against nematodes, and are widely used as nematicides. It is used. However, these compounds do not show practical control effects against soil diseases and are generally ineffective against bacteria. It also does not exhibit any practical herbicidal properties. That is, although they are generally remarkable effective as nematicides, they lack the ability to comprehensively control the aforementioned soil diseases and continuous cropping disorders. In addition, 1,2-dibromoethane and dichlorodiisopropyl ether, which are generally widely used, are generally highly effective against nematodes, but they cannot be used against some nematodes that are difficult to control. There are many cases where it is difficult to exhibit stable effects, and there is a strong desire for simpler nematicides that have more stable effects against all types of nematodes. From this perspective, the present inventors conducted extensive research on soil disinfection compositions that are effective against various soil diseases and nematodes, and found that TMTT and 1,2-dibromoethane,
One or two dichlorodiisopropyl ethers
By skillfully blending the seeds, this mixed composition, which has different activities, can be used against nematodes, the above-mentioned soil diseases caused by mixed infection with nematodes and filamentous fungi, and general soil diseases. It shows an unexpected and superior control effect that is higher than that when the soil disinfectant is used alone, and furthermore, this excellent control effect is exhibited at a surprisingly low dose, that is, it is a additive effect. The present invention has been completed by discovering that this can be achieved.
In the current situation where comprehensive continuous cropping damage countermeasures and comprehensive soil disinfection are strongly desired for an extremely wide range of crops, this composition, which has a soil disinfection effect at a surprisingly low dose, makes it possible to reduce the dosage. The economic advantage of being able to carry out soil disinfection at a low cost is extremely large. In addition, such a low dosage is desirable from the perspective of current environmental problems, and the present composition is extremely useful in terms of reducing phytotoxicity to agricultural crops and increasing safety in use. Of course, this composition can be applied with conventional formulations that can be used as soil disinfectants, such as oil solutions, emulsions, granules, etc. Next, some formulation examples will be described in order to explain the details of the present invention, but it goes without saying that the blending ratio, additives, and auxiliary agents can be varied widely in addition to those listed below. The parts in the examples indicate parts by weight. Example 1 Oil agent TMTT 11.0 parts, EDB 9.0 parts, chloroform 50.0
1 part and 30.0 parts of xylene were mixed to obtain a mixed oil of TMTT/EDB. Use by injecting the specified amount of this agent into the soil. Example 2 Oil Agent 8 parts of TMTT, 14.5 parts of DCIP, 40.0 parts of DMF, and 37.5 parts of xylol were mixed to obtain a mixed oil agent of TMTT/DCIP. Use by injecting the specified amount of this agent into the soil. Example 3 Emulsion 7.5 parts of TMTT, 4.5 parts of EDB, 39.0 parts of xylene, 40.0 parts of chloroform, and 9.0 parts of a mixture of polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, and dodecylbenzene sulfonate as an emulsifier were mixed, and TMTT was prepared. - A mixed emulsion of EDB was obtained. When using, dilute this agent with the specified amount of water and apply. Example 4 Emulsion 9.0 parts of TMTT, 8.1 parts of DCIP, 38.0 parts of DMF, 36.9 parts of xylol, and 8.0 parts of a mixture of alkylbenzene sulfonate, polyoxyethylene alkyl ether, and polyoxyethylene alkyl allyl ether as emulsifiers were thoroughly mixed to make TMTT. - A mixed emulsion of DCIP was obtained. When using, dilute this agent with the specified amount of water and apply. Example 5 Granules 10.0 parts of TMTT, 30.0 parts of bentonite, clay
30.0 parts and 16.5 parts of calcium carbonate are mixed well and made into granules using a dry compression granulator. Spray 13.5 parts of EDB all over the mixture, mix and adsorb it.
A mixed granule of TMTT and EDB was obtained. Spray the specified amount of this agent on the soil. Example 6 Granules 10.0 parts of TMTT, 35.0 parts of clay, bentonite
33.0 parts of calcium carbonate and 13.0 parts of calcium carbonate were mixed well and made into granules using a dry compression granulator. Spray 9.0 parts of DCIP all over the mixture, mix well, and let it absorb.
A mixed granule of TMTT/DCIP was obtained. Spray the specified amount of this agent on the soil. Example 7 Wettable powder 20.0 parts of TMTT, 52.5 parts of clay, 11.0 parts of white carbon, 5.0 parts of lignin sulfonate, and 2.5 parts of polyoxyethylene alkyl allyl ether are thoroughly mixed and the whole is pulverized. After uniformly spraying 9.0 parts of DCIP on this, mix the whole well and TMTT・
A mixed hydrating powder of DCIP was obtained. When using, dilute this agent with the specified amount of water and apply. Next, the control effects and characteristics of the composition of the present invention against soil diseases and nematodes will be explained in more detail with reference to test examples. Test Example 1 Efficacy test against tomato wilt A test was conducted in an in-house field contaminated with Meloidogyne incognita Kofoid et White. In the year before the treatment, one crop of tomatoes was grown after mixed inoculation with tomato wilt fungus (Fusarium oxysporum Schlechtendahl) that had been cultured for 3 weeks at 28°C in a soil-bran mixed medium to increase the density of nematodes and bacteria. The test was conducted in triplicate, with 1 area of 3 m ² and 10 plants. Tomato sowing (variety, Fukuju) is done on May 1st.
It was planted on June 10th. Fertilization management was in accordance with general practice. TMTT emulsion, EDB oil and
DCIP granules were tested. The drugs will be processed on May 26th.
The emulsion is injected with a syringe in a predetermined amount at 30cm intervals to a depth of 15cm. A predetermined amount of the granules was mixed to a depth of 15 cm. After treatment, a vinyl coating is applied, and after two weeks, the coating is removed and degassed.
It was planted the next day. The investigation was conducted on July 29th to determine the degree of onset of illness using the following criteria. After investigating the degree of disease onset, samples were washed with clean water and the root knot index was investigated. Incidence level = (severe) x 3 + (medium) x 2 + (small) x 1/3N x 10
0 (Severe): More than 50% of the plant height is wilted or dead (Medium): 16-49% of the plant height is wilted (Small): Less than 15% of the plant height is wilted The results are shown in Table 1. be.

【table】

[Table] Test example 2 Meloidogyne
Incognita Kofoid et White) A test was conducted using plastic pots (1/5000 are, Wagner pots) with one pot per district. Each test pot was filled with a certain amount of soil with a high larval density. Test chemicals include TMTT emulsion, EDB oil,
DCIP granules were tested. For the liquid drug, a drug injection hole was made in advance to a depth of 10 cm in the center of the pot using a glass rod, and a predetermined amount of drug was injected into each hole. For the granules, approximately 10 cm of soil from the top layer of the pot was taken out, mixed well with the chemical on a plastic sheet, and then refilled. For simultaneous granule and liquid treatment, the above granule treatment was first carried out, followed by a combination treatment similar to the above liquid treatment. Each pot was left uncovered and degassed 7 days after the chemical treatment.The next day, 10 tomato seeds (variety: large Fukuju tomato) were sown in each pot, and then the pots were maintained in a greenhouse. The survey was conducted 25 days after sowing, and the degree of parasitism was investigated using the index method. This test result is the second
As shown in the table. The theoretical value of root knot index is 100−
It was expressed as (a+b-ab)×100. However, a and b are the control value of each agent/100, and the control value is 100 minus the test value.

【table】

[Table] Test example 3 Meloidogyne
Incognita Kofoid et White) A test was conducted using plastic pots (1/5000 are, Wagner pots) in 2 pots per district. Each pot was filled with a certain amount of soil with a high density of larvae that were constantly breeding (3 cm from the upper edge of the pot). The test drugs were TMTT granules,
EDB oil and DCIP granules were tested. For the liquid drug, a drug injection hole was made in advance to a depth of 10 cm in the center of the pot using a glass rod, and a predetermined amount of drug was injected into each hole. For the granules, the soil from the top layer of approximately 10 cm was removed from the pot, mixed well with the chemical on a plastic sheet, and then refilled. For simultaneous granule and liquid treatment, the above granule treatment was first carried out, followed by a combination treatment similar to the above liquid treatment. Each pot treated with the above method was left uncovered, and after 7 days, the soil in each pot was taken out on plastic, degassed, and then refilled in the pot. One day later, tomato seedlings ( 1.5-2 true leaves)
(variety, large Fukuju tomato) was transplanted at a rate of 5 plants per pot and generally managed outdoors in a test pot ornament (corrugated roof). The seedlings were extracted 25 days after transplantation and the degree of parasitism was investigated using the index method. The theoretical value of the root knot index was calculated in the same manner as in Test 2. The results are shown in Table 3.

【table】

[Table] Test example 4 Pratylenchus
Test of control efficacy against Pratylenchus (penetrans Cobb)
Concrete frames (90cm x 90cm, depth 40cm) in which penetrans Cobb is constantly propagated are used, and each concrete frame contains radish seeds (variety: Minowase).
5 to 6 seeds were sown in each area, and each area was dotted in 9 areas. Thin out 15 days after sowing and plant 9 plants in 1 stile in 1 area (evenly spaced)
I conducted the test. Digging was carried out 80 days after sowing.
Other fertilizer application management was in accordance with general practice. Test chemicals include TMTT emulsion, EDB oil,
A DCIP emulsion was tested. For the treatment, divide the inside of the stile into 9 equal parts, make an injection hole in the center with a bamboo stick to a depth of 15cm, inject a fixed amount of medicine into each area, immediately cover the injection hole with soil, and then I sprinkled 3 liters of water on ward 1 with Nyoro and sealed the area. After two weeks of treatment, the seeds were degassed and seeded the next day. The survey was conducted twice: before chemical treatment and after digging, 50g of soil was collected from each area, and the number of white centipedes was investigated using the Behrmann method (25°C, 48 hours). In addition, the daikon radish taken out for investigation was washed with water,
The degree of root rot was investigated using an index method to determine the damage index. Damage index = Σ (index × number of stocks) / number of investigated stocks × 4 The results of this test are shown in Table 4.

【table】

Claims (1)

[Claims] 1 3,5-dimethyltetrahydro-2H-1,
A soil disinfectant comprising 3,5-thiadiazine-2-thione and one or two of 1,2-dibromoethane and dichlorodiisopropyl ether as active ingredients. 2 3,5-dimethyltetrahydro-2H-1,
The soil disinfectant for soil sterilization according to claim 1, which contains 3,5-thiadiazine-2-thione and 1,2-dibromoethane as active ingredients. 3 3,5-dimethyltetrahydro-2H-1,
The soil disinfectant for soil nematicides according to claim 1, which contains 3,5-thiadiazine-2-thione and 1,2-dibromoethane as active ingredients. 4 3,5-dimethyltetrahydro-2H-1,
The soil disinfectant for soil sterilization according to claim 1, which contains 3,5-thiadiazine-2-thione and dichlorodiisopropyl ether as active ingredients. 5 3,5-dimethyltetrahydro-2H-1,
The soil disinfectant for soil nematicides according to claim 1, which contains 3,5-thiadiazine-2-thione and dichlordiisopropyl ether as active ingredients.