JPS6147805B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention utilizes a thiol carbamate compound, a triazine compound, and a phenoxy compound.
The present invention relates to a herbicidal composition for paddy fields, which is characterized by containing a seed compound as an active ingredient. More specifically, as a thiol carbamate compound, S-(α,α-dimethylbenzyl)-N,N
-Pentamethylenethiol carbamate (hereinafter referred to as
MH-93), as a triazine compound, 2-methylthio-4,6-bis(ethylamino)-S-triazine (hereinafter abbreviated as simetrine), and as a phenoxy compound, 2-methyl-4- The present invention relates to a herbicidal composition for rice fields, which is characterized by containing three types of compounds as active ingredients: chlorophenoxythioethyl acetate (hereinafter abbreviated as phenothiol). The purpose of the present invention is to combine three types of compounds with various characteristics in specific proportions to eliminate grasshoppers, annual broad-leaved weeds, pine grass, firefly,
To provide a herbicidal composition for paddy fields which can accurately control perennial weeds such as Prunus japonicus and Prunus japonicum and has a wide range of suitable treatment periods with little chemical damage to paddy rice. MH-93 of the thiol carbamate compound
has already been published in Japanese Patent Application Laid-Open No. 1972-
98331 as a herbicide, and exhibits excellent activity against grass weeds, especially weeds, from the bud stage to the two-leaf stage, and is a low-fish-toxic herbicide that does not cause any phytotoxicity to rice. However, subsequent research has revealed that the activity is poor for highly grown wild grasses (2.5 leaf stage or above) and broad-leaved weeds when used at a field-level dosage of 200 to 300 g/10a, which takes economic efficiency into account. Simetrine, a triazine compound, is generally said to exhibit herbicidal power by inhibiting photosynthesis, and is effective against many annual broad-leaved weeds, but at a practical level of 45g/10a, it kills grasshoppers, fireflies, and weeds. etc., and have high temperature reactivity,
It is also known that it often causes phytotoxicity to rice. Phenoxy-based phenothiol is generally referred to as an auxin herbicide, and is explained to exhibit herbicidal power by causing abnormal growth of cells and tissues by disrupting plant hormones. Many of these drugs are highly effective against annual broad-leaved weeds, grasshoppers, Japanese grasshoppers, and other plants, but the practical level of dosage is 20 to 25 g/
10a has little effect on grass grasses. It is also known that because it exhibits herbicidal effects at low dosages, rice often exhibits callus root symptoms or growth suppression due to excessive dosage, abnormally low temperatures, etc. Various attempts have been made to combine the three types of drugs described above. For example, as a known composition, (1) S-ethyl-hexahydro-1H-azepine carbothioate (hereinafter abbreviated as molinate) as a thiol carbamate compound. Example (2) in which simetrine is added as a triazine compound, and ethyl 2-methyl-4-chlorophenoxybutyrate (hereinafter abbreviated as MCPB) is added as a phenoxy compound.
As a thiol carbamate compound, S-(p-
chlorobenzyl)-N,N-diethylthiol carbamate (hereinafter abbreviated as bentiocarb)
There is an example in which cymetrine is added as a triazine compound, and MCPB is added as a phenoxy compound. Furthermore, as an example of combining two drugs, (3) a composition of simetrine and phenothiol can also be seen. Although the compositions (1), (2), and (3) above have already been put into practical use as medium-term treatment agents, various disadvantages and defects have been identified in recent years. In other words, the composition (1) shows excellent efficacy against perennial weeds, including wild grasses and annual broad-leaved weeds, but the main ingredient, molinate, is toxic to fish, causing deformed fish, and its use is currently subject to restrictions in some areas. . In addition, although the composition (2) generally has excellent herbicidal power, the main ingredient, bentiocarb, has recently been found to cause dwarfing symptoms in rice due to changes in the age of rice and abnormal reduction in paddy fields due to the application of raw straw. has come to the fore and is becoming a major problem. Although the composition (3) is effective against annual broad-leafed plants and perennials such as Prunus japonicum, Prunus japonicus, Firefly, and Prunus japonicus, it has a defect in that it is significantly less effective against Novies belonging to the Poaceae family. From this point of view, the present inventors
As a result of intensive efforts to develop a mid-term herbicide that can be used on the 20th, the herbicidal composition for paddy fields according to the present invention has been completed. That is, the present invention combines the following three types of compounds into S-(α,α-dimethylbenzyl)-N,N
-Pentamethylene lentiol carbamate: 100
Parts by weight: 2-methylthio 4,6-bis(ethylamino)-S-triazine: 5 to 20 parts by weight 2-methyl-4-chlorophenoxyethyl acetate: 2.5 to 10 parts by weight. The present invention provides a herbicidal composition for paddy fields. The composition of the present invention compensates for the weak point of cymetrine or phenothiol, which is the weak point of grasses, by mixing MH-93, and the weak point of MH-93, which is annual broad-leaved and perennial grass species, is compensated for by mixing simetrine and phenothiol. The three types of compounds work cooperatively with each other to increase herbicidal power and are effective against a wide range of paddy field weeds. Furthermore, the composition completely overcomes various disadvantages observed in known compositions (1), (2), and (3). Furthermore, as is clear from the test examples, the composition of the present invention is effective even when treated at the leaf stage (3rd leaf stage) of grasshoppers, which cannot be controlled by a single agent or a mixture of cymetrin and phenothiol. By demonstrating this, we were able to greatly expand the scope of the appropriate period. For this reason, it is possible to control grass species at different growth stages that are often found under natural conditions. The composition of the present invention contains a mixture of three compounds: MH-93, cymetrine, and phenothiol, and the mixing ratio is 100% by weight of MH-93.
against simetrine 5-20, phenothiol
It is desirable to mix 2.5 to 10. More preferably, MH-93 is 100 and cymetrine is 10-100.
15. Good effects can be obtained if 5 to 8 phenothiols are mixed. When the composition of the present invention is actually used in the field, it is labor-saving to mix the above-mentioned active ingredient and an inert carrier and form it into granules using a general formulation method. Further, it can also be formulated into a hydrating powder, an emulsion, or the like, if necessary. It can also be used in combination with known bactericides, insecticides and growth regulators. Furthermore, the certainty of herbicidal efficacy can be increased by mixing adjuvants used in agricultural chemicals, such as spreading agents, wetting agents, and dispersing agents. Next, the formulation examples of the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples. Note that parts used in the examples represent weight percentages unless otherwise specified. Example 1 MH-93

[Formula] 10 parts Cymetrine 1.5 parts Phenothiol 0.7 parts Sodium alkylbenzenesulfonate 1.5 parts Sodium ligninsulfonate 1.5 parts Mixture of equal parts of clay and talc 84.8 parts After mixing and pulverizing the above, add water and knead to produce in the usual manner. Grind and obtain granules. Example 2 MH-93 12 parts Cymetrine 1.5 parts Phenothiol 0.5 parts Bentonite 58 parts Talc 25 parts Sodium alkylbenzenesulfonate 2.5 parts Polyvinyl alcohol A granulator in which 0.5 parts of polyvinyl alcohol were uniformly ground and mixed, then an appropriate amount of water was added and kneaded. Example 3: 10 parts of MH-93, 1 part of cymetrine, 1 part of phenothiol, 0.7 parts of sodium alkylbenzenesulfonate, 1.5 parts of sodium ligninsulfonate, 1.5 parts of a mixture of equal parts of clay and talc, and 85.3 parts of Example 1. Granules are obtained in the same manner. Example 4 Granules were obtained in the same manner as in Example 1 using MH-93 10 parts Cymetrine 1.5 parts Phenothiol 0.5 parts Sodium alkylbenzenesulfonate 1.5 parts Sodium ligninsulfonate 1.5 parts A mixture of equal amounts of clay and talc 85 parts. Example 5 MH-93 10 parts cymetrine 1.2 parts phenothiol 0.8 parts bentonite 60 parts talc 24 parts sodium dodecylbenzenesulfonate 1 part polyoxyethylene alkyl allyl ether
After mixing and pulverizing 1 part and 2 parts of sodium ligninsulfonate, the mixture is granulated by a conventional method. Example 6 MH-93 8 parts Cymetrine 1.6 parts Phenothiol 0.8 parts Sodium alkylbenzenesulfonate 1.5 parts Sodium ligninsulfonate 1.5 parts Mixture of equal amounts of clay and talc 86.6 parts The above ingredients are mixed and pulverized and granulated in a conventional manner. Example 7 MH-93 12 parts Cymetrine 1 part Phenothiol 0.6 parts Sodium ligninsulfonate 2.4 parts Polyoxyethylene alkyl allyl ether
2 parts talc 52 parts bentonite 30 parts Mix and crush the above ingredients and granulate using the usual method. Example 8 MH-93 30 parts Cymetrine 3.5 parts Phenothiol 1.5 parts Equal parts mixture of kaolin and diatomaceous earth 45 parts White carbon 10 parts Solpol (registered trade name) 5 parts Polyvinyl alcohol 5 parts Mix and grind the above to make a wettable powder get it. When using the composition of the present invention prepared in this way in paddy fields, the amount of active ingredient per 10g is 100g to 100g.
Paddy field weeds can be controlled by applying 1000g. More preferably, good results can be obtained by applying 200g to 600g. Next, test examples using the composition of the present invention will be explained. Test Example 1 Greenhouse Wagner Pot Test River gravel was placed in the lower layer of a 1/2000a Wagner pot, filled with dry paddy soil, and an appropriate amount of water was added to saturate the pot. After that, seeds of Japanese wild grass, Japanese cypress, Japanese cypress, Japanese firefly, and Japanese cypress were sown within about 3 cm of the surface layer, and two overwintering stocks of Japanese cypress and two wintering plants of Japanese cypress were transplanted. Next, two rice plants at the 2.5 leaf stage were transplanted into one plant. After that, the pots were gently submerged in water to a depth of 3 cm, and the pots were placed in a greenhouse to grow each plant. Then, when the wildflowers reached the three-leaf stage, 4 cm of flooding was prepared according to Example 1 in the same manner as the five types of granules (composition of the present invention) prepared according to Example 1.
Granules of MH-93 alone and commercially available mixture of cymetrine and phenothiol (trade name: GRAKYL) were treated to give a weight of 2 and 4 kg per 10a. Note that water continued to leak at a rate of 2 cm/day for 3 days after the chemical treatment, and thereafter the water was kept at a depth of 4 cm. The herbicidal power and rice were investigated on the 30th day after treatment with the chemical, and the remaining weeds were pulled out, washed with water, air-dried, weighed, and compared with the untreated plot. Rice was washed with water in the same way as weeds, and its growth status was observed. The evaluation was determined according to the following criteria and the results are shown in Table-1. Weeding power Level of rice damage 5: (amount of remaining grass) 0% ×: Death 4: (〃) 1-10% 〓: Severe damage 3: (〃) 11-20% 〓: Medium damage 2: (〃) 21- 40% +: Slight harm 1: (〃) 41-60% ±: Slight harm 0: (〃) 61% or more -: Harmless

【table】

[Table] Test Example 2 Outdoor Concrete Pot Test River gravel was placed in the lower layer of a 50 cm x 50 cm square concrete pot, filled with dried and sieved paddy soil, and an appropriate amount of water was added to saturate the pot. after that,
A certain amount of seeds of Japanese wild grass, Japanese cypress, Japanese cypress, Japanese firefly, and Helaomodaka were sown within 3 cm from the surface layer, and four overwintering plants of Japanese silver lily and four wintering plants of Japanese cypress were also transplanted. Next, two rice plants at the three-leaf stage were divided into one plant, and four plants were transplanted. After that, the seeds were submerged in water gently to a depth of 3 cm to prevent the seeds from floating. Then, the granules used in Test Example 1 were applied to the wildflowers at the 2.5 to 3 leaf stage in an amount of 4 kg per 10 a. Note that water continued to leak at a rate of 2 cm/day for 3 days after the chemical treatment, and thereafter the water was maintained at a depth of 3 to 4 cm. The investigation was conducted in the same manner as Test Example 1, and the results are shown in Table 2.

【table】

[Table] Test Example 3 Flooded growing season treatment Fill 200 cm ² pots with paddy soil that has been plowed, and plant wild grass (seeds: 30 seeds) in each pot.
Grains), firefly (seeds: 30 grains), and urikawa (tubers: 3 individuals) were planted, and each weed was grown in a greenhouse. When the 2.5- to 3-leaf stage of wildflowers, 2-3 leaf stages of firefly, and 2-3 leaf stages of scallops were reached, the herbicide hydrating agent shown in Table 3 (prepared according to Example 2) was applied. was diluted and treated in predetermined amounts. After that, the pots are grown in a greenhouse,
The amount of remaining weeds (above-ground parts) remaining 30 days after the above treatment was determined and compared with the amount of remaining weeds (above-ground parts) in untreated pots to determine the percentage of remaining weeds. The results are shown in Table-3.

【table】

[Table] Test Example 4 Filled paddy soil was placed in a 200 cm ² pot, and four plants were transplanted, each containing two rice plants at the two-leaf stage. After that, the plants were gently submerged in water to a depth of 3 cm and grown in a greenhouse. Eight days later, when the rice had grown to 35 leaves, it was treated with each drug shown in Table 4 in the form of granules prepared according to Example 1. Thereafter, the pots were grown under control in a greenhouse, and the stem and leaf weights, root weights, and number of stems of the growing rice were measured 30 days after the treatment. The results are shown in Table-4.

【table】

【table】

[Table] **: Ratio to untreated area (%)

Claims (1)

[Claims] 1 The following three compounds are S-(α,α-dimethylbenzyl)-N,N
-Pentamethylene lentiol carbamate: 100
Parts by weight: 2-methylthio 4,6-bis(ethylamino)-S-triazine: 5 to 20 parts by weight 2-methyl-4-chlorophenoxyethyl acetate: 2.5 to 10 parts by weight. A herbicidal composition for paddy fields.