JPS5928529B2 - Composition for soil sterilization - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 3,5-dimethyltetrahydro-2H-1,3
・5-thiadiazine-2-thione (hereinafter referred to as TMTT), N-tetrachloroethylthiotetrahydrophthalimide (hereinafter referred to as captafor), pentachlornitrobenzene (hereinafter referred to as PCNB), tetrachloroisophthalonitrile (hereinafter referred to as chlorothalonil) ) or screws (
The present invention relates to a soil sterilizing composition containing as an active ingredient one or a mixture of two or more of dimethylthiocarbamoyl) disulfide (hereinafter referred to as thiuram).

It is a well-known fact that the recent diversification of vegetable cultivation and the spread of greenhouse horticulture have caused damage from soil diseases as well as continuous cropping problems in a wide range of crops, and that solving this problem has become an important agricultural issue. .

In other words, soil diseases of crops include seedling blight, vine splitting disease, and white silk disease of cucumbers, melons, watermelons, and cucurbits, half-wilt disease of tomatoes, eggplants, etc., bacterial wilt disease, Chinese cabbage, orchid, etc. These include root rot of pudding, leaf wilt and yellow wilt of strawberries, dry rot of onions, damping-off of flower stalks, bulb rot, and crest disease of apples and mulberries.

Although these are extremely difficult to control, the current situation is that (1) they have low toxicity to humans and animals (can be used safely);
2) It is effective against a wide range of soil diseases, (3) It is not only a temporary effect (it has a residual effect), (4) It is simple to use and easy to use in agricultural work, and (5) it produces resistant bacteria. A soil disease control agent that meets the necessary conditions as a soil disinfectant fungicide, such as being difficult to use, has not yet been developed.

In particular, there is a strong desire to develop a drug for root rot, which causes severe damage to orchid, Chinese cabbage, and cabbage, causing severe damage to continuous crops.

TMTT used in the composition of the present invention is suitable for crop cultivation in Japan.
The major pathogenic bacteria mentioned above that cause severe damage as soil diseases include Fusarium sp., Pythium sp., Rhizoctonia sp.
Plasmodiophora (Plasmodioph)
In addition to soil diseases caused by Meloidogyne sp.
), Pratylenc
It is extremely effective in controlling soil nematodes such as H.hus sp.), and is particularly effective in vegetable cultivation in Japan where continuous cropping problems are a problem due to intensive cultivation, as well as tobacco, konjac, chrysanthemum, carnation, and other flower cultivation. It is an essential pest control agent for crops.

TMTT also has a great effect of suppressing the germination of weed seeds, and from this aspect as well, it provides a great advantage for cultivation beds.

It is known that when TMTT is applied to soil as a pesticide, it decomposes within a few days after application in warm climate conditions where the soil temperature is 10°C or higher, producing formaldehyde, hydrogen sulfide, methylisothiocyanate, methylamine, etc. In particular, methyl isothiocyanate, formaldehyde, and hydrogen sulfide are involved in controlling the aforementioned diseases, nematodes, and weeds.

In addition, after soil application, TMTT mixes well with the soil at a depth of usually 15 to 20 crIL to ensure that the decomposed gas permeates uniformly into the soil, and to prevent the effective gas from escaping and reducing the effectiveness. Cover the soil surface with a vinyl sheet etc. for 10 days.

TMTT exhibits excellent effects when used as described above, but on the other hand, the decomposed gas itself is harmful to plants, so if plants come into direct contact with or absorb the decomposed gas, they may be severely affected. 5TMTT has a drawback in that it must be thoroughly degassed before sowing or planting crops because it causes phytotoxicity.

That is, (1) phytotoxicity is likely to occur if decomposition is insufficient or degassing is insufficient.

(2) The soil disinfection effect is high, but because it depends on the sterilization and nematicidal effects of gas, the effect is temporary and the sterilization effect cannot be sustained.

In general, in farmland, residues from previous crops can become a source of infection, and pathogens can easily be carried in and re-contaminated through the inflow of soil and rainwater from adjacent contaminated fields. Therefore, it is difficult to expect a sufficient pest control effect.

(3) In addition, in order for TMTT to exhibit sufficient effects, it requires a large amount of active ingredient, 20 to 30 kg per 10 ares, and has many practical drawbacks, such as being uneconomical.

One of the active ingredients of the composition is a bactericidal ptafol agent,
Chlorothalonil is widely used as a foliar spray fungicide for various crop diseases.

Diseases that these compounds are effective against include scab disease (
E 1sinoe fawcetti B 1ta
Diaporthe citri Wolf
) Venturia nashicola
Tanaka et Yamamoto) black spot disease (Alternaria Kikuchiana)
Tanaka) Plague (Phyto voice thora 1)
nfestar1s(Montagne) de Ba
ry) anthracnose (CCo11etotrichu lagena)
rumEllis et Halsted), etc., and are known to be effective as foliar spray control agents against a wide range of diseases.

However, the following soil diseases, such as clubroot disease (Plasmodiophora bra
ssicae Woronin), Fusarium oxyporum S
chlechtendahl), Verticillium albo
-atrumReinke et Bertho
It has not been found to be sufficiently effective as a broad soil disinfectant against various diseases such as ld).

In addition, thiurams are used to treat apple leaf spot disease (Alternaria mali Roberts).
) Venturia 1naequali
Although it is used as a foliar spray control agent and seed disinfectant such as S. winter) and as a seed disinfectant, and for controlling some soil diseases, it not only has no practical effect on the aforementioned clubroot disease and half-body wilt. It has drawbacks such as causing significant drug damage when used in doses effective against clubroot and other diseases.

In addition, PCNB agents are effective against damping-off disease (Rh1zoctonia).
sp, ), has long been known as a soil fungicide effective against clubroot disease, but in recent years, the density of seedlings has increased in areas where oilseed vegetables are continuously cultivated, and the effect is almost stable with the usual dosage. I can't expect that.

In addition, there is an environmental problem in that large amounts of pesticides must be avoided from the viewpoint of residual agricultural chemicals in the soil.

Generally, the above-mentioned captafor, chlorothalonil, thiuram,
Each of PCNB's chemicals is used to combat soil diseases that are considered to be major causes of continuous crop failure, including root rot, which causes severe damage.
It lacks the power to practically control wilt, half-wilt, etc.

From this point of view, the present inventors conducted a wide range of research on agents effective against soil diseases, and found that by skillfully blending TMTT with one or more of captafor, chlorothalonil, thiuram, or PCNB, this mixture The composition exhibits an extremely excellent control effect against the above-mentioned soil diseases for which it is difficult to exert a sufficient effect with each single compound, and furthermore, the composition can synergistically control the diseases at surprisingly low doses. discovered.

In addition, in order for this composition to exhibit ideal effects under soil conditions, we discovered that the dosage form when formulating into granules is extremely important, and as a result of comparative research on the divine dosage form, The inventors discovered that the following formulation of granules is the most preferable and most practical; that is, granules in the particle size range of 100 to 300 microns cause the least drug damage and are most effective, and the present invention was completed. .

Of course, the present composition can be easily formulated into conventional preparations that can be used as soil disinfectants, such as aqueous phase preparations, oil preparations, emulsions, granules, etc.

Next, some formulation examples will be described in order to explain the present invention in detail, but it goes without saying that the blending ratios, additives, and auxiliary agents for each formulation may be varied over a wide range other than those listed below.

The parts in the examples indicate parts by weight.

Example 1 Granules 13 parts of TMTT raw material, 8 parts of captafor raw material, 40 parts of calcium carbonate powder, 25 parts of bentonite, 14 parts of clay.
5 parts were mixed and made into amorphous granules using a compression granulator, and the liquid solution was crushed and sieved to obtain mixed granules of TMTT and captafor with a particle size of 100 to 300 microns.

Example 2 Granules 13 parts of TMTT raw material, 8 parts of chlorothalonil raw material, 29 parts of bentonite powder, 20 parts of clay, and 30 parts of calcium carbonate powder were thoroughly mixed and made into irregularly shaped granules using a compression granulator.
This was further crushed and then divided to obtain TMTT/chlorothalonil mixed granules having a particle size of 100 to 300 microns.

Example 3 Powder TMTT active substance 15 parts, captafor active substance 8 parts, talc 75 parts
1 part and 2 parts of dispersant were mixed well, the whole was pulverized, and TMTT
・A mixed powder of captafor was obtained.

Example 4 After mixing 30 parts of wettable powder TMTT raw material, 30 parts of thiuram raw material, 5 parts of lignin sulfonate, 3 parts of polyoxyethylene alkyl ether, 5 parts of white carbon, and 27 parts of clay, the whole was pulverized, A mixed hydrating powder of TMTT and thiuram was obtained.

Example 5 Emulsion 10 parts of TMTT raw material, 5 parts of PCNB raw material, 3 parts of Kijirol
3 parts, dimethylformamide 40 parts, polyoxyethylene alkyl ether 5 parts, calcium dodecylbenzenesulfonate 5 parts, polyoxyethylene alkylaryl-
Two parts of ether were mixed and dissolved to obtain a mixed emulsion of TMTT-PCNB.

Example 6 Oil agent 10 parts of TMTT raw material, 10 parts of PCNB raw material, 48 parts of chloroform, 22 parts of dimethylformamide, 10 parts of kerosene
A mixed oil agent of TMT T-PCNB was obtained by mixing and dissolving the two parts.

Next, we will discuss the excellent additive effects of these disinfectant compositions for soil disinfection according to the present invention, as well as the effects and excellent practicality of the granules of this mixed composition in the particle size range of 100 to 300 microns. Give and explain.

Test Example 1 Control effect test on Chinese cabbage root rot A white porcelain pot with an inner diameter of 9 CIrL was inoculated with dormant spores of the root rot fungus in sterilized soil (I X 106Spores/T).
300 d of fLl soil was added to prepare the test soil.

As test chemicals, TMTT powder, PCNB powder, chlorothalonil powder, captafor wettable powder, and thiuram aqueous solution were tested.

The powder and aqueous phase agents tested were each dosed at a depth of 5 cm.
It was mixed well with IrL soil and refilled.

The plots were divided into 3 rows, with 1 pot (10 seedlings) per ward.

After treatment, spray water to prevent the surface of the pot from becoming extremely dry.
Appropriate humidity was maintained, and Chinese cabbage seeds (variety: Ohsho) were sown after 7 days.

No degassing was performed. The investigation was conducted 35 days after sowing by washing the diseased roots with water and dividing the degree of root gall formation into four stages from θ to ■.
The degree of root cup formation was calculated by the method of Williams et al.

In other words, the theoretical value of the control value of the degree of root hop formation is (a + b
-ab) Expressed as control value x 100.

However, a and b are □00 of each agent It was displayed in

In addition, TMTT and PCNB, chlorothalonil, captafor,
Each Thiuram agent was thoroughly mixed and applied.

The test results are shown in Table 1.

(Note) *I PCNB powder is manufactured by Hokuko Chemical Industry ■.
Contains 20% pentachlorni and lobenzene as active ingredients.
Contains powder.

*2 Chlorothalonil powder is manufactured by Takeda Pharmaceutical Company Ltd. and contains 10% tetrachloroisophthalonitrile as an active ingredient.

*3 Captafor water phase agent is a water phase agent manufactured by Nihon Nohyaku ■ that contains 80% N-tetrachloroethylthiotetrahydrophthalimide as an active ingredient.

*4 Thiuram hydrating agent is a hydrating agent manufactured by Ohmukai Shinko Kagaku Kogyo ■ that contains 80% bis(dimethylthiocarbamoyl) disulfide as an active ingredient.

*5 TMTT powder is a formulation of Kanesho Chemical Industry ■.
3,5-dimethyltetrahydro-2H- as an active ingredient
It is a powder containing 98% of 1,3,5-thiadiazine-2-thione.

The same applies below.

Test Example 2 Chinese cabbage Control effect test against clubroot rot The test bacteria, test crops, treatment method, and zoning system were all conducted in accordance with Test Example 1.

Regarding the mixing treatment, TMTT (fine granules were used as they were mixed with a predetermined mixed drug).

The method for calculating the pesticidal value is the same as in Test Example 1.

The results are shown in Table 2. Test example 3 Chinese cabbage control effect test against clubroot disease Tests were carried out on-site for local equipment.

Chinese cabbage seeds (variety: Shin-Tokyo) were sown on August 18th, and planted on September 5th in furrows of 60 crrL and 1 plant spacing of 54 crrL.

Others were based on common practice.

1st section 12m 2.4 consecutive races. A predetermined amount of the drug was treated on August 29th, and immediately mixed using a rotary.

No coating was applied. Gas was removed using a rotary machine on September 4th, and seeds were sown the next day.

The survey was conducted on October 30th (collection time) by randomly selecting about 8 plants from each district and investigating the diseased plant rate, yield, degree of root gall, etc.

The degree of root bulge was determined according to the method of Williams et al.

In processing the drug, the TMTT emulsion and the mixed drug were thoroughly mixed and processed.

The pest control value was calculated in the same manner as in Test Example 1.

The results are shown in Table 3.

Test example 4 Chinese cabbage control effect test against clubroot disease Tested TMTT granules and chlorothalonil powder.

The test bacteria, test crops, treatment method, and division were conducted according to Test Example 1.

Regarding the mixing treatment, TMTT granules were used as they were mixed with chlorothalonil powder.

The method for calculating the control value for the degree of root clot formation was carried out in accordance with Test Example 1.

The results are shown in Table 4.

*Test 1 Test Example 5 Control effect and chemical damage of the TMTT/captafor mixed granules shown in Example 1 against cucumber seedling damping-off caused by Pythium genus bacteria.

TMT with different particle sizes in soil naturally infected with Pythium spp.
20 kg/10 a each of mixed granules of T. captafor,
30kg/10a was mixed and treated, and after being covered for 3 days, degassing was performed once. On the same day, four-leaf cucumber seeds were sown, and 10 days after sowing, the germination rate and the rate of stand-off of seedlings were investigated.

The soil temperature at the time of the test was 15.5 to 17.3.

The results are shown in Table 5.

All phytotoxicity inhibits growth - ~ ■ None Vital (Note) * Both TMTT/captafor mixed granules are formulations from Kanesho Chemical Industry ■, and contain 12.5% TMTT and 7% captafor as active ingredients. However, it is a mixed granule that differs only in particle size.

Test Example 6 Control effect and phytotoxicity of the TMTT/chlorothalonil mixed granules shown in Example 2 against cucumber seedling damping-off disease caused by Phizoctonia M bacteria.

Phizoctonia 5olani on sterilization
The cells were inoculated with bacteria and subjected to treatment after 122 days.

20 kg/1 each of TMTT and chlorothalonil mixed granules
0a, 3oky/loa mixed treatment, coating diameter 1 for 3 days
After degassing, four-leaf cucumber seeds were sown on the same day, and diseased plants were removed and investigated at any time until 15 days after sowing.

The soil temperature at the time of the test was 16.8 to 18.9.

The germination rate and bacterial damping rate were calculated in the same manner as in Test Example 5.

The results are shown in Table 6.

All phytotoxicity inhibits growth - ~ Geki Seonami (Note) * [The combined granules of TMTT and chlorothalonil contain 12.5% TMTT and 7% chlorothalonil
Mixed granules containing each active ingredient and differing only in particle size.

From the above trends, it has become clear that, regarding this mixed composition, granules in the particle size range of 100 to 300 microns cause the least phytotoxicity and have excellent effects.

Reference example Relationship between particle size and drift (dispersion) Drift is related to drug loss and is an important factor related to drug efficacy, as well as scattering and contamination to the sprayer and the environment.

From this point of view, the most preferable particle size for processing the present mixed composition granules was investigated.

If the specific gravity is assumed to be 1.0, the theoretical calculation will be as shown in the table below.

From the above, the range of particle diameters that have appropriate dispersibility and less drift is 100 to 500 microns.

However, from the viewpoint of phytotoxicity, particles of 500 μm are too coarse, so the preferred range is about 100 to 300 μm.

Claims (1)

[Claims] 13,5-dimethyltetrahydro-2H-1,3,5-
Thiadiazine-2-thione and N~tetrachloroethylthiotetrahydrophthalimide, pytachlornitrobenzene, tetrachloroisophthalonitrile or bis-(
A soil sterilizing composition containing one or more dimethylthiocarbamoyl disulfides as an active ingredient. 23,5-dimethyltetrahydro-2H-1,3,5~
The soil disinfection composition according to claim 1, comprising thiadiazine-2-thione and N-tetrachloroethylthiotetrahydrophthalimide. 33,5-dimethyltetrahydro-2H-1,3,5~
The soil disinfection composition according to claim 1, comprising thiadiazine-2-thione and pentachlornitrobenzene. 43,5-dimethyltetrahydro-2H-1,3,5-
The soil sterilizing composition according to claim 1, comprising thiadiazine-2-thione and tetrachloroisophthalonitrile. 53,5-dimethyltetrahydro-2H-1,3,5-
The soil disinfection composition according to claim 1, comprising thiadiazine-2-thione and bis(dimethylthiocarbamoyl) disulfide. A composition for soil disinfection according to any one of claims 1 to 5, having a particle size in the range of 6100 to 300 microns.