JPH05229903A - Paddy herbicidal tablet - Google Patents

Abstract

PURPOSE:To provide paddy herbicidal tablets easy to apply, and also to provide simple application method using the same. CONSTITUTION:The objective paddy herbicidal tablets comprising (A) as herbicidal ingredient (s), 4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5- phenacyloxypyrazole, 2-chloro-2,6'-diethyl-N-(2-propoxyethyl)acetanlide, and, as necessary, 2-methylthio-4,6-bis(ethylamino)-s-triazine, (B) a surfactant, (C) a foaming agent, and (D) an oil-absorbing carrier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a simple tablet for application of a drug in weeding in paddy fields, and a simple method for treating the drug.

[0002]

2. Description of the Related Art Conventionally, weeding methods for paddy fields, especially in the early stages of rice cultivation
Examples of the herbicidal method in the middle stage include a fine powder solid carrier of the herbicidal component, fine granules formulated with other adjuvants, a method of directly applying the granules, and a method of diluting a wettable powder with a large amount of water and then applying. .. Examples of the method without using a fine powder solid carrier include a method of spraying an emulsion in which the herbicidal component is dissolved in an organic solvent as it is, and a method of spraying a flowable agent in which the finely ground herbicidal component is dispersed and suspended in water as it is.

However, in applying fine granules, granules, and wettable powders, a heavy duster or granulator containing the medicine is required, for example, usually 3 to 4 kg per 10 ares.
By walking around the paddy fields to spray the granules of
Alternatively, by using a large Niagara hose from the ridge, the drug must be evenly distributed. Therefore, the transportation and spraying of the chemicals not only requires a severe labor, but also the rice seedlings are often damaged, which is not desirable for their growth. Even when applying emulsions and flowable agents, the weight of the medicine is reduced to some extent and a large sprayer is not required, but it is necessary to use a container that discharges a fixed amount of medicine.
It is still necessary to roam the paddy fields for more even spraying.

On the other hand, an invention which attempts to solve the above-mentioned problems in the prior art (JP-A-3-128301, 3-1).
73802, No. 3-223203). Although these applications disclose herbicides for paddy fields containing herbicidal active ingredients, surfactants, carbonates and water-soluble solid acids, specific combinations of herbicidal ingredients according to the present invention are No disclosure is seen.

[0005]

DISCLOSURE OF THE INVENTION That is, the present invention relates to the herbicidal component 4- (2,
4-dichlorobenzoyl) -1,3-dimethyl-5-phenacyloxypyrazole (generic name: pyrazoxifene, hereinafter abbreviated as compound A), 2-chloro-2 ', 6'-
Diethyl-N- (2-propoxyethyl) acetanilide (generic name: pretilachlor, hereinafter abbreviated as compound B)
And 2-methylthio-4,6-, which is optionally contained
A paddy herbicide tablet comprising bis (ethylamino) -s-triazine (generic name: cimetrin, abbreviated as compound C below), a surfactant, a foaming agent, and an oil-absorbing carrier, and the tablet. 10 per 10 are
The present invention relates to a paddy field weeding method of applying 200 to a paddy field flooded so that the total weight of the tablets is 500 to 1500 g, and dispersing the herbicidal component in the paddy water.

The surfactant in the present invention is a herbicidal component,
It imparts hydrophilicity to oil-absorptive carriers, for example, fatty acid salts such as mixed fatty acid soda soap, castor oil potassium soap; sodium lauryl sulfate, higher alcohol sodium sulfate, lauryl sulfate triethanolamine, ammonium lauryl sulfate, etc. Alkyl sulfate ester salts; alcohol sulfate ester salts such as sodium alcohol sulfate ester; alkylbenzene sulfonate salts such as sodium dodecylbenzenesulfonate; alkylnaphthalenesulfonate salts such as sodium alkylnaphthalenesulfonate; sodium dioctylsulfosuccinate Such as alkylsulfosuccinates; such as sodium alkyldiphenyletherdisulfonate; alkyldiphenyletherdisulfonates such as sodium alkylphosphate; Rukylic phosphoric acid ester salt; polyoxyethylene lauryl ether sulfate sodium salt, polyoxyethylene alkyl ether sulfate sodium salt, polyoxyethylene alkyl ether sulfate triethanolamine polyoxyethylene alkyl ether sulfate ester salt such as triethanolamine; polyoxyethylene alkylphenyl ether sulfate sodium salt Polyoxyethylene alkylaryl ether sulfate ester salt such as; β-naphthalene sulfonic acid sodium salt formalin condensate, special aromatic sulfonic acid sodium salt formalin condensate salt of naphthalene sulfonic acid formalin condensate; sodium polycarboxylate Polycarboxylic acid salts such as; polystyrene sulfonates; polyoxyethylene alkyl ether phosphates; anions such as lignin sulfonates Surfactants;

Of polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene higher alcohol ethers; polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether Polyoxyethylene alkylaryl ethers such as; polyoxyethylene styryl aryl ethers such as polyoxyethylene styryl phenyl ethers; oxyethylene oxypropylene block polymers such as polyoxyethylene polyoxypropylene block polymers; sorbitan monolaurate, Sorbitan monopalmirate, sorbitan monostearate, sorbitan tristearate, sorbita Sorbitan fatty acid esters such as monooleate, sorbitan trioleate, sorbitan sesquioleate, sorbitan distearate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan Polyoxyethylene sorbitan fatty acid ester such as monooleate; glycerol monostearate, glycerin fatty acid ester such as glycerol monooleate; polyoxyethylene hydrogenated castor oil;
Polyoxyethylene glycerin stearate,
Polyoxyethylene glycerin fatty acid esters such as polyoxyethylene glycerin oleate;
2,4,7,9-Tetramethyl-5-decyne-4,7-
Diol, 3,6-dimethyl-4-octyne-3,6-
Acetylene glycol such as diol; 3-methyl-
Nonionic surfactants such as acetylene alcohols such as 1-butyn-3-ol are mentioned. These surfactants may be used as one kind or as a mixture of two or more kinds, and may be used as a mixture of anionic and nonionic surfactants.

The blowing agent in the present invention is a combination of an acidic substance and an alkaline substance which reacts in the presence of water to generate a gas. Examples of the acidic substance include those which show acidity themselves or show an acidity when dissolved in water, such as citric acid, tartaric acid, oxalic acid, succinic acid, maleic acid, phthalic acid, malic acid and adipic acid. Organic acids; hydrogen salts such as sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium hydrogen sulfate; alums such as potassium alum and ammonium alum, and the like. Examples of alkaline substances include Examples thereof include carbonates such as sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate and ammonium carbonate; bicarbonates such as sodium bicarbonate and potassium bicarbonate, and percarbonates such as sodium percarbonate.

Since the compound B as a herbicidal ingredient contained in the present invention is an oily substance, when it is used as it is as a component of the tablet of the present invention and prepared, sufficient hardness cannot be obtained or the oily substance oozes out. Because there are things
It is used by impregnating it with an oil absorbing carrier. As the oil-absorbing carrier that can be used here, any oil-absorbing carrier having an oil absorption of 50 wt% or more and having no adverse effect on the obtained tablet may be used. For example, finely divided amorphous silicon dioxide (Brand name: Curvelex, Syloid, Nipseal, Tokseal, Aerosil, etc.), Starch hydrolyzate (Brand name: Pineflow, Paindex, etc.), Talc (Brand name: LM-P, LM-R, High filler, etc.) ,
Diatomaceous earth (Brand name: Radiolite F, Radiolite SP
F, Celite SSC, Celite FIOSS, Ceratom M
W-23, Ceratom MW-25, Oplite), artificial compound of diatomaceous earth / lime (trade name: Microcell, etc.), World Cerabon, a mixture of kaolinite and sericite (trade name: Sieglite MC, etc.), silicic acid Calcium (product name: Torohero, etc.), light calcium carbonate (product name:
Toyostar TF-X, etc.), Silicate light calcium carbonate (trade name: Toyofine TF-X200, etc.), acid clay, powdered activated carbon, carbon black, natural earth graphite, perlite (pearlite) processed product (trade name: TOPCO Etc.), ultrafine particles of anhydrous aluminum oxide (trade name: aluminum oxide C, etc.), ultrafine particles of titanium oxide (trade name: titanium dioxide P25, etc.), basic magnesium carbonate, magnesium aluminate silicate (trade name: Neusilin, etc.) ),
Examples thereof include silica / alumina synthetic filler (trade name: Zeofil, etc.), hydrous magnesium silicate (trade name: Miraclay, etc.) and the like, and these may be mixed and used as necessary. The oil absorption amount here is JISK5101.
It was measured by.

In selecting the surfactant, the foaming agent, and the oil-absorbing carrier, it depends on the kind of the herbicidal component and the mixing ratio of the whole preparation. Therefore, an appropriate one is actually selected by trial and error experiments. I have to do it.

The blending ratio of each component in the paddy field herbicidal tablet of the present invention is 10 to 40 parts by weight, preferably 12 to 30 parts by weight of compound A as a herbicidal component, expressed in terms of weight ratio based on the whole tablet. And the compound B is 3 to 10 parts by weight, preferably 4.5 to 6 parts by weight, and when the compound C is contained as a herbicidal component, the compound C is 1 to 5 parts by weight, preferably 1 to 3 parts by weight. And the surfactant is 0.
5 to 8 parts by weight, the foaming agent is 22 to 84.5 parts by weight, and the oil absorbing carrier is 1 to 15 parts by weight. The foaming agent is usually prepared in a weight ratio of the acidic substance to the alkaline substance of 1: 2 to 2: 1. Of course, even those outside these ranges are included in the present invention as long as the desired effects are exhibited.

When the oil-absorbing carrier is impregnated with the compound B as a herbicidal component, it can be impregnated with a surfactant if necessary. The ratio is compound B1
0.05 to 1 part by weight, preferably 0.1
~ 0.5 parts by weight. The surfactant mentioned here is the same as the above-mentioned one, but in order to impart hydrophilicity to the compound B in particular, as the surfactant, for example, polyoxyethylene styryl phenyl ether, polyoxyethylene alkylaryl ether, polyoxy Nonionic surfactants such as ethylene phenyl alkyl aryl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene hydrogenated castor oil, polyoxyethylene / polyoxypropylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester; alkyl Anionic surfactants such as aryl sulfonates, alkyl sulfosuccinates, and alkyl phosphate ester salts may be used. These surfactants may be used as one kind or as a mixture of two or more kinds, and may be used as a mixture of nonionic and anionic types.

The tablet of the present invention comprises a binder in addition to the above components,
A solid carrier and other agrochemical auxiliaries can be contained if necessary. The binder may be any one as long as it binds the constituent particles, and is preferably water-soluble. For example, carboxymethyl cellulose, a salt thereof, dextrin, polyethylene glycol, polyvinyl alcohol, polyalkylene glycol. , Polyvinylpyrrolidone, lignin sulfonate, gum arabic, starch paste, other starches, sucrose and the like. Further, as the binder in the present invention, even if the binder itself is not generally used as a binder, any binder can be appropriately used as long as it has a function of binding each component particle. Examples of substances that can be used in this way include acidic substances such as succinic acid, adipic acid, phosphoric acid and salts thereof; alkaline substances such as sodium carbonate and sodium bicarbonate; liquid paraffin;
Solvents having a high boiling point such as isoparaffin; waxes; animal and vegetable oils and the like.

Examples of solid carriers include mineral fine powders such as kaolin, talc, clay and bentonite; inorganic salts such as anhydrous sodium sulfate and sodium chloride; organic substances such as urea; magnesium stearate; and other pesticide aids. Examples of the agent include commonly used solvents, decomposition inhibitors, phytotoxicity reducing agents, dispersion stabilizers, antifungal agents, disintegrating agents, drying agents and the like. Although the amount of use of them cannot be unconditionally specified, it is generally 0.1 to 0.1% as a ratio to the whole tablet.
Although it is 40 parts by weight, it can be used by replacing a part of the foaming agent.

Further, the tablet of the present invention may contain a pigment mainly used in the food field, such as Food Blue No. 1, in which case the pigment serves as a guide during the spraying operation, so that the spraying operation is efficient. It is possible to do so, and it is effective in avoiding the overlapping spraying.

The tablet of the present invention is usually produced by the following method or a method similar thereto. The compound A as a herbicidal component and the compound C optionally contained therein are pulverized in advance in order to improve the dispersibility in water, and thus the particle size is 50
μm or less, with respect to Compound A, desirably 0.1 to 5
It is used as fine particles of μm, and a surfactant, a foaming agent and an oil-absorbing carrier are also crushed and used as needed. Further, the compound B as a herbicidal component is used by mixing it with a surfactant as necessary and impregnating it with an oil absorbing carrier. As a method for producing tablets, for example, the herbicidal component, the surfactant and the effervescent agent treated as described above are mixed at the same time, or any other components are mixed in advance to make all the components uniform. And crushed to a particle size of 0.5 to 50 μm, and compression-molded by a usual method using a compression molding machine such as a tableting machine or a briquette machine. For example, a method may be mentioned in which the ingredients are granulated, wettable or tabletted, and then mixed with the other remaining ingredients and crushed or crushed to form tablets. The molding pressure of the compression molding machine depends on the components in the preparation, the mixing ratio, and the type and performance of the compression molding machine. Therefore, it is necessary to select an appropriate pressure by trial and error experiments. Further, when the tablet of the present invention is industrially produced, it can be produced continuously in accordance with a usual tablet formulation method. In this case, in order to enable continuous compression molding, the above-mentioned compound is added. It is desirable to provide liquidity.

When a binder, a solid carrier and / or other agrochemical auxiliary is used here, it is uniformly mixed with the herbicidal component and the surfactant which have been previously treated as described above and pulverized to obtain a wettable powder. A method of mixing with a foaming agent after forming, a method of mixing with the herbicidal component treated as described above, a surfactant and a foaming agent at the same time, or a method of previously mixing with any component and further mixing with the other components, etc. Is mentioned. Needless to say, the tablet production method described above may be appropriately modified in consideration of drug efficacy, formulation properties, etc.

The tablets are manufactured in various shapes and sizes such as a circular plate shape, an oval plate shape, a rectangular plate shape, a rod shape, a spherical shape, and an elliptic spherical shape, depending on the manufacturing method and compression molding machine. .. Since the drug efficacy is not significantly affected by the shape of the tablet, any shape, size, or weight may be used, but the shape may be spherical or circular plate-like and the diameter may be 1 to 5 cm, Thickness 0.2-3 cm, weight 1-
It is preferably 150 g in terms of formulation and drug application. Also,
As long as the desired effects of the present invention are not impaired, the above-mentioned ingredients may be used to form a capsule.

As a method for producing the capsule, for example, the herbicidal component treated as described above, a surfactant and a foaming agent are uniformly mixed, and if necessary, a binder, a solid carrier and / or other agrochemical auxiliaries are used. In addition, they are uniformly mixed, and the crushed pulverized product is granulated, and the granules are filled in capsules made of water-soluble cellulose, water-soluble starch, gelatin or the like, or the pulverized product is not granulated, A method of filling a wettable powder into a capsule as it is, further, a method in which any of the ingredients are granulated as described above and the remaining ingredients are tableted and crushed according to the above-mentioned tablet manufacturing method are used. Similarly, a method of filling a capsule may be mentioned. This capsule can also be formulated into various shapes, sizes and weights as in the case of tablets. In addition to those prepared as described above, the capsules are not filled with the pulverized product or wettable powder, but are directly wrapped with a water-soluble film of water-soluble cellulose, water-soluble starch, polyvinyl alcohol, gelatin or the like. Is also included.

When the tablet of the present invention is applied to a flooded paddy field, a gas is generated upon contact with water, the herbicidal component is rapidly eluted in the paddy water, and a surfactant also acts to remove the herbicidal component. Disperses in water and disperses uniformly. Thus, when the tablet of the present invention is administered to a paddy field, the herbicidal component can be promptly dispersed in the paddy water, and for example, the herbicidal component can be evenly distributed in the paddy water after a few hours to a few hours, so that the herbicide damage to paddy rice. It is possible to control weeds uniformly without giving them.

When the paddy field is used for weeding with the tablet of the present invention, 10 to 200 tablets are applied per 10 ares and the total weight of the tablet is 500 to 1500 g. It is not desirable, or a great deal of labor is required for the spraying work. A desirable application method cannot be unequivocally defined due to differences in tablet production method, size, herbicidal component, surfactant, effervescent agent, oil-absorbent carrier and other additives, mixing ratio, etc. Ingredients 150-350g 1.5 per tablet
Divide to ~ 35g and apply 10 to 100 pieces. Thus, only one tablet or capsule needs to be applied to 10 to 100 m ² and therefore it is not necessary to enter the paddy field and can be thrown into the paddy field of the area from the ridge, so the spraying work is simple and the conventional drug application method can be applied. It is advantageous in comparison. When the paddy field is weeded using the tablet of the present invention, it is generally most preferable when applied to transplanted paddy rice 3 to 15 days after seedling transplantation, and for direct seeded paddy rice 5 to 20 days after seeding in the early to middle stage of paddy rice cultivation. Although the effect can be obtained, it can be applied at any other time as long as the tablet is applied without causing any trouble in terms of efficacy and phytotoxicity. Further, even if the tablet of the present invention is once dispersed in an appropriate amount of water and applied locally in a paddy field, a desired effect in terms of medicinal effect and phytotoxicity may be obtained.

[0022]

EXAMPLES Formulation examples will be described as examples of the present invention.
This description does not limit the present invention in any way. In the following formulation examples, "parts" are expressed on a weight basis.

Formulation Example 1 Compound A1 previously pulverized to a particle size of 0.1 to 5 μm with a supersonic jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.)
9.38 parts and sodium bicarbonate 21.81 each crushed in advance with a centrifugal crusher to a particle size of 50 μm or less
Parts, sodium carbonate 14.09 parts and succinic acid 28.9
4 parts, compound C 1.54 parts, magnesium stearate 0.5 parts, higher alcohol sodium sulfate ester (trade name: Monogen Y-500; Dai-ichi Kogyo Seiyaku Co., Ltd.)
0.5 parts) and sodium carboxymethyl cellulose (trade name: Serogen PR; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
Compound A was mixed and pulverized with 2.0 parts by a centrifugal pulverizer so as to have a particle size of 50 μm or less.

On the other hand, 4.67 parts of compound B and polyoxyethylene phenyl alkylaryl ether sulfate (trade name: Solpol 7290P; Toho Chemical Industry Co., Ltd.)
An oily product obtained by mixing 0.7 parts of the product with starch was hydrolyzed with starch (trade name: Pineflow; manufactured by Matsutani Chemical Co., Ltd.) 5.37.
Parts and finely divided amorphous silicon dioxide (trade name: Carplex CS-7; manufactured by Shionogi Seiyaku Co., Ltd.) were uniformly mixed and ground in a mortar to impregnate 0.50 parts of the mixed ground product. Obtained.

Then, the above-mentioned blends (a) and (b) were mixed and pulverized in a mortar to obtain a uniform powder, which was then tableted (gauge indicated pressure:
70 kg / cm ² , ram diameter: 13.5 cm) and compression molded, diameter 5 cm, thickness 1.6 cm, weight 50 g
To obtain a tablet.

Formulation Example 2 (1) Compound A 18.90 parts (2) Compound C 1.58 parts (3) Sodium bicarbonate 21.13 parts (4) Sodium carbonate 14.09 parts (5) Succinic acid 28. 46 parts (6) Monogen Y-500 (trade name) 0.50 part (7) Serogen PR (trade name) 5.00 parts (8) Compound B 4.84 parts (9) Solpol 7290P (trade name) 0. 70 parts (10) Pine Flow (trade name) 4.50 parts (11) Fine granular amorphous silicon dioxide 0.30 part (trade name: Carplex # 80; manufactured by Shionogi & Co., Ltd.) The ingredients were blended according to the above Preparation Example 1, compression molded using a tableting machine (gauge indicated pressure: 3 t), and the diameter was 2.5.
A tablet having a cm, a thickness of 1.6 cm and a weight of 12.5 g was obtained.

Formulation Example 3 In Formulation Example 2 above, the pressure indicated by the gauge of the tabletting machine was 2.
Tablets having a diameter of 2.5 cm, a thickness of 1.7 cm and a weight of 12.5 g were obtained in the same manner except that the tablets were replaced with 4 t.

Formulation Example 4 (1) Compound A 19.31 parts (2) Sodium bicarbonate 22.00 parts (3) Sodium carbonate 14.50 parts (4) Succinic acid 30.27 parts (5) Magnesium stearate 0 .50 parts (6) Monogen Y-500 (trade name) 0.50 part (7) Serogen PR (trade name) 1.00 part (8) Compound B 4.72 parts (9) Solpol 7290P (trade name) 0 .70 parts (10) Pine Flow (trade name) 6.00 parts (11) Cuprex CS-7 (trade name) 0.50 parts The above ingredients were blended according to the above Preparation Example 1, and a tableting machine ( Compression molding using gauge indicated pressure: 1.5t), diameter 2
A tablet having a size of 0.5 cm, a thickness of 0.5 cm and a weight of 2.54 g was obtained.

Formulation Example 5 In the above Formulation Example 4, the pressure indicated by the gauge of the tablet machine was 4 t.
4cm in diameter and 1.4c in thickness
A tablet weighing m and weighing 25 g was obtained.

Next, test examples of the present invention will be described. Test Example 1 Two-leaf stage rice seedlings (cultivar: Nihonbare) were mechanically transplanted into paddy fields that had been scraped in advance, and a test area of 10 m × 5 m (FIG. 1) was provided using a plastic ridge sheet. Three days after transplanting the rice seedlings, tubers of Cyperus cylindrica that were germinated were planted at 6 locations (points marked with X in FIG. 1), and other weeds were spontaneously generated, but many of them were generated. On the other hand, a comparison section having the same size as the test section of the present invention and subjected to the same treatment was simultaneously provided.

The next day, the submersion depth was adjusted to 5 cm, and one tablet prepared in Formulation Example 1 was dropped into the center of the test plot. Granules prepared according to the conventional formulation method were uniformly sprayed on the comparative plots, which corresponded to the tablets. The amount of the herbicidal component in the granules was 18 g / a for compound A and 4.5 for compound B.
g / a, compound C is 1.5 g / a. The leaf age of each weed at that time was 0.5 to 1 leaf stage for Nobie, 0.5 leaf stage for firefly and konjac, and the early stage of development of Azena and Spodoptera litura.

5 weeks and 7 after application of tablets and granules
After a week, the growth conditions of paddy rice and weeds were visually observed and evaluated based on the following evaluation criteria, and the results shown in Table 1 were obtained.

[0033]

[Table 1]

The herbicidal effect of the test zone of the present invention is high overall,
No difference was observed with the comparison plot. Also, regarding the phytotoxicity to paddy rice, paddy rice in the vicinity where the tablet of the present invention was dropped did not occur more strongly than the other ones, and no difference from the comparison plot was observed.

Test Example 2 A 2-leaf stage rice seedling (variety: Koshihikari) was mechanically transplanted to a paddy field that had been scraped in advance, and a 12.5 m × 8 m test area was prepared using a plastic ridge sheet (FIG. 2). Was established.

Four days after transplanting rice seedlings, the submerged depth is 5 cm.
2 tablets prepared in Formulation Example 1 were dropped (points marked with ⊚ in FIG. 2: 2 points). After the dropping process 3,
5 and 24 each time, the paddy water at points a to e in FIG. 2 was collected at a submersion depth of 2 to 3 cm, and the concentrations of the herbicidal component compounds A, B and C in water were determined by liquid chromatographic analysis, The results shown in Table 2 were obtained.

[0037]

[Table 2]

Concentrations of the herbicidal component compounds A, B and C in water were detected at the same level after 24 hours with no significant difference at the points a to e. Therefore, since the herbicidal component compounds A, B and C are uniformly dispersed in the paddy field, a good herbicidal effect and safety for paddy rice can be expected as in the case of Test Example 1 above. Although the concentration of the herbicidal component compound A in water is lower than the theoretical concentration in water, it is considered that this is due to the property of the compound A that the water solubility is low and the soil adsorption occurs relatively quickly. This can be seen from the comparative test example described below.

Comparative Test Example In a greenhouse, a paddy soil was packed in a 1 / 1000a plastic case, water was introduced, and scraping was performed. On the other hand, a 1 / 1000a plastic case that does not fill paddy soil was also provided.

On the next day, the water depth was adjusted to 4 cm and the herbicidal component compound A was prepared according to the conventional formulation method so that the compound A was 18 g / a, the compound B was 4.5 g / a and the compound C was 1.5 g / a. The granules thus prepared were evenly distributed on each plastic case. Depth of water is 2 cm every 2, 5 and 24 hours after spraying
Water was collected at a certain level, and the concentration of compound A in water was determined by liquid chromatographic analysis, and the results shown in Table 3 were obtained.

[0041]

[Table 3]

The concentration of the herbicidal component compound A in water was lower than the theoretical concentration in water as in the case of the tablet of the present invention, even though the granules were uniformly dispersed, and when the paddy soil was filled, it was not filled. The numbers are even lower than the case.
From this, the fact that the concentration of the compound A in water in Test Example 2 below the theoretical concentration in water is due to the property that the compound has a low water solubility and that soil adsorption occurs relatively quickly. Is suggested.

[0043]

[Brief description of drawings]

[0044]

[Figure 1]

It represents a paddy field divided into 10 m × 5 m,
X indicates the point where the tuber of Spodoptera litura was implanted, and ⊚ indicates the point where the tablet was dropped.

[0046]

[Fig. 2]

A paddy field divided into 12.5 m × 8 m is shown, ⊚ indicates points where tablets were dropped, and a to e indicate points where paddy water was collected.

Claims (3)

[Claims] 1. Herbicidal ingredients 4- (2,4-dichlorobenzoyl) -1,3-dimethyl-5-phenacyloxypyrazole and 2-chloro-2 ', 6'-diethyl-N-
A paddy field herbicide tablet containing (2-propoxyethyl) acetanilide, a surfactant, a foaming agent, and an oil absorbing carrier. 2. The herbicidal component 4- (2,4-dichlorobenzoyl) -1,3-dimethyl-5-phenacyloxypyrazole, 2-chloro-2 ', 6'-diethyl-N- (2
-Propoxyethyl) acetanilide and 2-methylthio-4,6-bis (ethylamino) -s-triazine,
A paddy field herbicide tablet containing a surfactant, a foaming agent, and an oil-absorbing carrier. 3. The paddy field herbicidal tablet according to claim 1 or 2 is applied to a paddy field flooded in an amount of 10 to 200 tablets per 10 ares and a total weight of the tablets of 500 to 1500 g. A method for weeding paddy fields, which comprises dispersing the components in the paddy water.