JPH0415201B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite herbicide for paddy fields and a weeding method, and in particular, it has a wide herbicidal spectrum that includes both annual paddy field weeds and perennial paddy field weeds, and shows excellent herbicidal effects against paddy field weeds. , a compound herbicide for paddy field cultivation of Japonica species in which the phytotoxicity of one of the ingredients of the compound herbicide to paddy rice is significantly reduced, especially when applied to paddy field weeds before germination or in the early stages of growth after germination. , exhibits a significantly superior weed effect against paddy field weeds, including both annual paddy field weeds and perennial paddy field weeds, including perennial paddy field weeds for which it has been difficult to achieve a satisfactory herbicidal effect,
Furthermore, the present invention relates to a unique composite herbicide and weeding method for Japonica rice that does not cause substantial chemical damage to Japonica rice. More specifically, the present invention is based on the following formula (1) The compound represented by and the following formula (2) A Japonica rice plant with reduced chemical damage to Japonica rice seedlings, characterized in that it is applied to the water surface for a period of about 1 to about 15 days after transplanting the Japonica rice seedlings in combination with a compound represented by Regarding paddy field weeding methods. The present invention also provides the above formula
The present invention also relates to a composite herbicide for use in paddy fields for cultivating paddy rice of Japonica species, which is characterized by containing the compound (1) and the compound of formula (2) as active ingredients. 2 expressed by the above formula (1) used in the present invention
-[(4,6-dimethoxypyrimidin-2-yl)
Aminocarbonyl-aminosulfonylmethyl]benzoic acid methyl ester is a known herbicidally active compound described in JP-A-57-112379, and
S-(4-chlorobenzyl) represented by the above formula (2)
-N,N-diethylthiol carbamate is also a known herbicidally active compound called SATURN. JP-A-57-112379 mentioned above describes that the sulfonamide compound represented by the general formula, which includes many compounds described therein, can be used in combination with other commercially available herbicides. Some known herbicidally active compounds including the compound of formula (2) are exemplified. However, there are no specific examples of the combination of the compound of the general formula and other commercially available herbicides, let alone the combination of the compound of formula (1) and the compound of formula (2) that are particularly selected in the present invention. Not disclosed. Furthermore, the said Japanese Patent Application Publication No. 57-112379
The issue includes the results of pot tests (field conditions) (Table A, Table B, Table C), 4G (40% growth retardation) to 8G (80% growth retardation), 2C (20% yellowing). / 齽壤)
It was shown that the effects of
The results of the test (paddy field condition) (Table E) show that there was no effect on rice, but there was a herbicidal effect on grasshoppers, water chestnuts, etc. However, in this test, there is no mention of the type of rice to be tested in either pot tests under field conditions or paddy field conditions, and there is no mention of field tests under natural conditions at all. In recent years, manual weeding of paddy field weeds has ceased to be carried out due to labor-saving cultivation and rationalization through mechanization, and the reality is that weeding with herbicides has no choice but to be carried out. Therefore, despite showing satisfactory high herbicidal activity with a wide herbicidal spectrum against both annual paddy field weeds and perennial paddy field weeds that are difficult to weed and propagate in tubers and rhizomes,
It is desired to provide a herbicide for paddy field weeds that does not cause phytotoxicity or other adverse effects on paddy rice. However, the reality is that it is not possible to provide a herbicide that fully satisfies such wishes, regardless of whether it is a single agent or a combination agent. The present inventors have conducted research in order to provide a paddy field herbicide and weeding method that can meet such demands. As a result, it was discovered that the combined use of the compound (1) and the compound of formula (2) results in a unique composite herbicide for paddy fields that meets the above-mentioned needs that have been desired but could not be provided. According to the research of the present inventors, although there are differences depending on the nature of the paddy soil, the condition of the soil, air temperature, water temperature, weather conditions, region, etc., in field tests under natural conditions, the above formula ( 1) The compounds are shown in Table 3 below.
As shown in Fig. 1, it exhibits excellent herbicidal activity even at a low application rate of 75 g/ha, but on the other hand, it has been discovered that it often causes phytotoxicity to paddy rice that cannot be put to practical use. The facts in this field test under natural conditions are:
Although this may be possible, it was a surprising result in light of the results of the simulated paddy field pot test (Table E) in the aforementioned Japanese Patent Application Laid-Open No. 57-112379. In order to solve the technical problem based on this new knowledge, the present inventors further continued their research. As a result, as shown in Table 1 later, the phytotoxicity of the compound of formula (1) to paddy rice showed considerable differences depending on the type of paddy rice, and it was found that the phytotoxicity of the compound of formula (1) to paddy rice differed considerably depending on the type of paddy rice, and it was found that the phytotoxicity of the compound of formula (1) to paddy rice varied considerably depending on the type of paddy rice. Japonica KATO
Type] of paddy rice and Indica species [OsLsubsp.Indica KATO, also called Indian type]
The susceptibility to the compound of formula (1) is significantly different from that of rice of the type [type], and at the application concentration at which Indica rice has a practically negligible effect, Japonica rice can already be put to practical use. We have obtained new findings that the compound of formula (1) cannot be put to practical use as a paddy field herbicide for cultivating paddy rice of the Japonica variety at the application rate at which it exerts its excellent herbicidal effect. . The present inventors conducted research to solve new technical problems based on the above-mentioned new findings. As a result, although the above compound of formula (1) can exhibit its excellent herbicidal effect, even if it is used at an application rate that causes phytotoxicity to paddy rice of the Japonica variety, the combination of this compound and the above compound of formula (2) As a result, they discovered that the chemical damage to Japonica paddy rice can be reduced to a practically negligible level. That is, according to the research of the present inventors, by selecting a combination of the formula (1) compound and the formula (2) compound specified in the present invention, when the formula (1) compound is applied alone. Although it can exert its excellent herbicidal effect, even if it is applied at a rate that makes it difficult to avoid chemical damage to Japonica paddy rice,
without a substantial reduction in its herbicidal efficacy.
It has been discovered that it is possible to achieve a completely unexpected and surprising selective phytotoxicity-reducing effect in that only phytotoxicity to Japonica rice can be selectively and significantly reduced. Furthermore, it has been found that the combined use of the compound of formula (1) provides the benefit of achieving a further improved broad herbicidal spectrum. For example, as shown later in Table 3, in field tests under natural conditions, even at low application rates such as 75 g/ha, the compound of formula (1)
It exhibits excellent herbicidal activity against a wide range of other annual and perennial paddy weeds, although it is somewhat unsatisfactory against other annual paddy weeds and perennial paddy weeds. However, by simply further combining the compound of formula (2) at the same application rate, while substantially maintaining its excellent herbicidal activity (improved for Japanese millet), only phytotoxicity against Japonica rice was reduced. , it can be seen that a completely unexpected and remarkable selective effect of reducing drug damage was achieved, in which the reduction was practically negligible. Furthermore, according to the present invention, in addition to achieving the above-mentioned unexpected and surprising selective phytotoxicity reducing effect, compared to the known application rates conventionally employed for weeding perennial paddy field weeds, for example, With a low application rate of about 1/20 to 1/40, it has a wide weeding spectrum that includes both annual paddy field weeds and perennial paddy field weeds, and has excellent weed control in paddy fields without causing phytotoxicity to Japonica rice. A surprising improvement is achieved in that the process can be performed labor-savingly. Furthermore, the toxicity to fish is low, with TLm of 20ppm in 48 hours.
It has low fish toxicity equivalent to Class A (test fish: young carp), exhibits high activity at the low application rate, and has the advantage of not causing chemical damage, making it a unique product that does not cause problems with environmental pollution. It has been found that a method for weeding paddy field weeds for Japonica rice and a composite herbicide for Japonica rice can be provided. In addition, as summarized above, the previously completely unknown and surprisingly excellent weeding effect of paddy field weeds is obtained after transplanting (rice transplantation) Japonica seedlings into paddy fields.
It has been found that the results are particularly well achieved by surface application of the formula (1) compound and the formula (2) compound in combination over a period of about 2 to about 14 days, preferably about 2 to about 14 days. Furthermore, it has been found that the above-mentioned effect on paddy field weeds is conveniently and reliably exhibited in fields under natural conditions, and is of extremely high practical value. Therefore, an object of the present invention is to provide a unique method for weeding paddy field weeds and a herbicide complex thereof, which exhibits an excellent weeding effect on paddy field weeds and a selective effect on reducing chemical damage. The above objects and many other objects and advantages of the present invention will become more apparent from the following description. As mentioned above, the compounds of formula (1) and compound of formula (2) of the present invention are known weed-active compounds, and their physicochemical constants and production methods are already well known. The combination ratio of the above formula (1) compound and formula (2) compound of the present invention is appropriately selected within a range that does not substantially impair the excellent paddy weed herbicidal effect and chemical damage reducing effect of the composite herbicide of the present invention. can do. For example, the expression
(1) Compound: Formula (2) compound = 1: about 20-50 (weight ratio)
An example of the ratio of combined use of Moreover, the composite herbicide for paddy rice of the Japonica variety of the present invention comprises the compound of the above formula (1) and the compound of the formula (2).
In addition to the compound, it can further contain various auxiliary agents, various agricultural chemicals, etc., and can also be prepared in accordance with methods known per se, such as powders, granules, granules, tablets, suspensions, etc. It can be made into an emulsion, a wettable powder, a concentrated emulsion, an aerosol, or any other desired dosage form. Furthermore, it can also be used in combination with other herbicides and other agricultural chemicals. Examples of the above-mentioned auxiliary agents include kaolinite, attabalsite, montmorillonite, diatomaceous earth, bentonite, talc, phyllite, calcined vermiculite, silica, magnesium silicate, ammonium sulfate, magnesium sulfate, calcium sulfate, disodium phosphate, Solid or liquid carriers or diluents such as starch, water, aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, ethylene glycol, cellosolve, methyl cellosolve, etc.; alkylaryl sulfonates, alkyl sulfates, polyoxyethylene alkyl phosphates; ate, polyoxyethylene lauryl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan monolaurate, polyethylene glycol alkyl ether, polyoxyethylene alkyl phenyl ether, alkylbenzene sulfonate, lignin sulfonate, emulsifiers, dispersants, etc.
Wetting agents; other auxiliary agents can be exemplified. The composite herbicide for cultivating paddy rice of the Japonica variety of the present invention may be in the form of a composition used in combination with auxiliary agents such as those exemplified above, or may be in the form of a composition that does not contain such auxiliary agents for concentrated spraying. It can also be. The content of the active ingredient can be selected as appropriate, for example, the total amount of the compound of formula (1) and the compound of formula (2) is about 0.01 to about 100%, preferably about 0.1 to about 90%, based on the weight of the herbicide.
%. According to the method of the present invention, the compound of formula (1) and the compound of formula (2) are used together for about 1 to about 15 days, more preferably about 2 to about
It is preferable to apply it to the surface of flooded rice fields over a 14-day period because it shows particularly excellent herbicidal effects and selective phytotoxicity-reducing effects on paddy field weeds, and phytotoxicity to paddy rice can be ignored. The above period can be selected as appropriate depending on the region of rice cultivation, the variety of Japonica rice, the type and growth condition of paddy field weeds, the weather, and other variable conditions. It is particularly preferable to apply during the above-mentioned suitable period, since applying it too soon may have an adverse effect on young paddy rice plants, and applying it too late will reduce the herbicidal effect on paddy field weeds. When applying to the water surface, it is sufficient to spray it on the flooded paddy fields to which the Japonica rice seedlings have been transplanted, and there is no need to avoid adhering to the leaves of the paddy rice seedlings to some extent. It is preferable to apply for a period of time. For combined water surface application, it is common to apply the combination in the form of a pre-prepared complex herbicide, but if desired, single agents of formula (1) and formula (2) compounds can be mixed on the spot. They may be applied in combination, or they may be applied in combination at approximately the same time. As long as the selective drug damage reduction effect is not impaired, there is no need for complete simultaneous application. Furthermore, upon application, the composite herbicide for paddy rice cultivation of the Japonica species of the present invention exhibits an excellent selective herbicidal effect at a significantly reduced application rate compared to the conventional application rate known for conventional paddy field herbicides. In addition, it shows excellent results in that it acts effectively against annual and perennial weeds with a wide herbicidal spectrum and exhibits a selective chemical damage reduction effect. Conventional paddy herbicides are usually applied in an amount of active ingredient on the order of, for example, about 2,000 to about 4,000 g/ha in order to achieve the desired effect, but the composite herbicide for cultivating Japonica rice of the present invention The agent is a compound of formula (1) from about 65 to about
Excellent herbicidal effects are shown at significantly reduced application rates of the compound of formula (1), such as 120 g/ha, preferably about 70 to about 110 g/ha, especially about 75 to about 100 g/ha. Of course, the nature and condition of the paddy soil, natural conditions,
The amount of application can be increased or decreased as appropriate depending on the region, variety of Japonica paddy rice, and other conditions. According to the present invention, annual and perennial paddy weeds can be effectively weeded with a wide weeding spectrum. Furthermore, it exhibits a satisfactory herbicidal effect on Japanese millet, and has the benefit of not causing any phytotoxicity to Japonica rice. Examples of such perennial paddy weeds are Sagittaria pygmaea, Sagittaria trifolia, and Scirpus pygmaea.
hotarui), Cyperus serotinus,
Examples include perennial paddy weeds such as Eleocharis acicularis and Eleocharis kuroguwai. Examples of annual paddy weeds include Ec, Cyperus difformis, and Monochoria.
vaginalis), Rotala indica, Lindernia procubens, Dopatrium junceum, Elatine
triandra), etc. Almost all varieties of paddy rice cultivated in Japan belong to the Japonica variety.
For example, Koshihikari, Nishihomare, Setohomare, Kitahikari, Sasanishiki, Nihonbare and many other varieties are known and are the target varieties of the present invention. Hereinafter, several embodiments of the herbicide for paddy field weeds and the weeding method for cultivating Japonica paddy rice of the present invention will be illustrated in more detail by Examples as well as comparative examples. Examples 1 to 6 (Herbicide composition examples) 1 Wettable powder formula (1) compound and formula (2) compound (weight ratio 1:28)
80%wt sodium alkylnaphthalene sulfonate
2%wt Sodium lignin sulfonate 2%wt Synthetic amorphous silica 3%wt Kaolinite 13%wt The ingredients were mixed and the particle diameter was determined using a hammer mill.
Grind to less than 5μ and mix again. 2 Wettable powder formula (1) compound and formula (2) compound (weight ratio 1:30)
50% wt sodium alkylnaphthalene sulfonate
2% wt Methyl cellulose 2% wt Diatomaceous earth 46% wt The ingredients are mixed, coarsely ground with a hammer mill, then ground with an air mill to a diameter of 10μ or less, and mixed again. 3 Granule formula (1) compound and formula (2) compound (weight ratio 1:28)
25%wt Pre-granulated bentonite base carrier 75%wt A methylene chloride solution of the compounds of formulas (1) and (2) is spray impregnated onto the surface of a 75%wt pre-granulated bentonite carrier and air-dried. 4 Extruded granules Formula (1) compound and Formula (2) compound (weight ratio 1:25)
25%wt Anhydrous sodium sulfate 10%wt Calcium lignin sulfonate 5%wt Sodium alkylnaphthalene sulfonate
1%wt Bentonite 59%wt Mix each component and crush with a hammer mill, approx.
Add 12% water and mix. This is cut into extrusion lengths of about 3 mm using an extrusion granulator with a diameter of 3 mm to make granules. 5 Low concentration granules Formula (1) compound and Formula (2) compound (weight ratio 1:30)
1% wt N-dimethylformamide 9% wt Attapulsitate 90% wt The active ingredients are dissolved in the solvent and sprayed onto the particles in a rotary blender. After spraying is complete, run the blender for a while. 6 Oil-based suspension Formula (1) compound and Formula (2) compound (weight ratio 1:35)
25%wt Polyoxyethylene sorbitol hexaoleate 5%wt Higher aliphatic hydrocarbon oil 70%wt Grind each component in a sand mill to particles of approximately 5μ or less. This product can be used either extended in oil or emulsified in water. Reference Example 1 Susceptibility (phytotoxicity) of the compound of formula (1) to Japonica and Indica rice varieties: - Paddy soil was placed in a 1/5000 are Wagner pot, and after watering, fertilizing, and puddling, the following three types of rice seeds, Indica : IR-24 Indica: RP-93 Japonica: After germination treatment of Nihonbare, the seeds were sown (direct sowing) under submerged conditions. The rice field water was kept at 2-3 cm during the test period. The drug (compound of formula (1)) was applied to the water surface of paddy rice at the 0.5 to 1 leaf stage or the 1.5 to 2 leaf stage, respectively, in the amounts shown in Table 1. The survey was conducted on the 17th day after treatment.
Evaluation was performed using the following 10-step method. [Pharmaceutical damage] 0...No effect on growth 1...Slight growth suppression on plant height and tillers 2...Slight growth suppression on plant height and tillers 3...Significant growth suppression on plant height and tillers 4...Obvious growth suppression on plant height and tillers 5... Plant height, growth suppression at tillering, considerable yellowing 6... Plant height, growth suppression at tillering, obvious yellowing 7... Plant height, growth suppression at tillering, significant yellowing 8... Plant height suppression, significant yellowing at tillering Significantly inhibited 9...almost withered state 10...completely withered If the rating exceeds around 2.5, substantial chemical damage will occur, and if the rating is 3 or higher, it cannot be put to practical use.

[Table] Control -

(Untreated)

Example 7 and Comparative Examples 1 and 2 Selective phytotoxicity-reducing effect of the formula (2) compound on phytotoxicity of the formula (1) compound on Japonica paddy rice (stability improvement) ), we conducted a standard test using a 1/5000 are Wagner pot with a water leakage condition of 2 cm/8 hours per day. Seedlings of the 2.5-leaf Japonica paddy rice Nihonbare grown in the seedling box were transplanted to the above pots. The drug treatment was carried out one day after transplantation at the application rate shown in Table 2 below.
During the test period, a water depth of 3 cm was maintained under the above water leakage conditions. Observation surveys were conducted on the 13th and 20th day after drug application. The results are shown in Table 2 below. Evaluation (drug damage) is the same as described in Table 1.

[Weeding effect]

0: More than 90% of the weed amount in the control (untreated area) remains. 1...80% or more and less than 90% of the weed amount in the control (untreated area) remains. 2...More than 70% and less than 80% of the amount of weeds in the control (untreated area) remained. 3...60% or more and less than 70% of the weed amount in the control (untreated area) remains. 4...More than 50% but less than 60% of the amount of weeds in the control (untreated area) remained. 5...40% or more but less than 50% of the amount of weeds in the control (untreated area) remains. 6...30% or more and less than 40% of the amount of weeds in the control (untreated area) remains. 7...20% or more and less than 30% of the amount of weeds in the control (untreated area) remains. 8...10% or more and less than 20% of the amount of weeds in the control (untreated area) remains. 8.5…5% or more of the weed amount in the control (untreated area) or 10%
Less than 100% remain. 9...2.5% or more of the weed amount in the control (untreated area) or 5%
Less than 100% remain. 9.5...Approximately 2.5% or more of the amount of weeds in the control (untreated area) remained. 10...No residual amount of weeds. 8 or more, preferably 9 or more is a practical excellent weed effect. In the table, the weed symbols are as follows. Ec: Japanese violet Mv: Konagi Bl: Other annual broad-leaved weeds (Kikashigusa, Azena, Japanese chickweed, etc.) Ea: Japanese pine beetle Sh: Firefly Sp: Urikawa Ac: Helaomodaka Cs: Japanese chickweed

[Table] As shown in the results in Table 3 above, in field tests under natural conditions, the compound of formula (1) was applied alone at a reduced application rate to annual and perennial paddy fields other than Ec. Although it has a practically excellent herbicidal effect on weeds, it is accompanied by phytotoxicity that makes it impractical. However, even when applied under the same conditions at such an application rate that causes herbicidal damage, the combined use of the compound of formula (2) results in only herbicidal damage being suppressed without any substantial decrease in the herbicidal effect. It can be seen that this is significantly reduced. Example 10 A 1/5000 are Wagner pot was filled with sandy paddy soil, and after watering, fertilizing, and puddling,
Rice seedlings (variety: Nihonbare) at the leaf stage were transplanted. Two days after transplantation, the water surface was treated with the compound of formula (1) and the compound of formula (2) at the application rate shown in Table 4 at the same time. Twenty days after the chemical treatment, the degree of chemical damage to rice was evaluated according to the same 10-step method as described in Reference Example 1. The results are shown in Table 4.

[Table] As shown in the results in Table 4 above, when formula (1) compound is applied alone at 100 g per ha, it causes growth inhibition (phytotoxicity) with no practical growth on rice, but when the formula (1) compound is applied at the same amount, formula (1) ) compound and 2000g and 3000g per ha
When the formula (2) compound [the weight ratio of formula (1) compound: formula (2) compound is 1:20 and 1:30, respectively] is treated in rice fields at the same time, the It can be seen that growth-inhibiting chemical damage is significantly reduced. This completely unexpected effect of reducing phytotoxicity makes the method of the present invention widely applicable even to sandy paddy soil, which is prone to phytotoxicity. Example 11 Fill a 1/5000 are Wagner pot with alluvial clay loam, add granular fertilizer containing 15% of each of N, P, and K, and then pour water; after mixing, flood the pot to a depth of 1 cm. Japanese grasshopper (Ec), Japanese grasshopper (Mv), annual broad-leaved weeds (Kikashi, Azena, Japanese chickweed, etc.) (Bl), Japanese cypress (Cd), and Japanese scallop (Sh) were sown in the pots mentioned above, and separately, Pinus cabbage (Ea) and Japanese scallop (Sh) were sown in the above pots. Sp), underground rhizomes of Cyperus japonica (Cs) were placed on the beds.
Apart from weeds, young paddy rice (variety: Nihonbare, approx.
2.3 leaves), and four plants were transplanted into each pot, one per plant. Weeds were treated at the 1.5 to 2.0 leaf stage, and paddy rice was treated on the 5th day after transplanting by dissolving a prescribed amount of the drug in acetone, diluting it with water, and dropping it with a pipette. For weeds, 4 weeks after chemical treatment,
After about 3 weeks had elapsed, the paddy rice was evaluated for chemical and herbicidal effects using the same criteria as above. The results are shown in Table 5 below.

【table】

[Table] Anilide As shown in the results of Table 5 above, the formula according to the present invention
In the combined use of the compound (1) and the compound of formula (2), the chemical damage reduction effect of the compound of formula (1) is clearly seen, whereas in the combined use of the compound of formula (1) and butachlor, the drug damage actually increases. are doing.

Claims (1)

[Claims] 1. The following formula (1) The compound represented by and the following formula (2) A japonica rice plant containing a compound represented by the following as an active ingredient in a weight ratio of the compound of formula (1) to the compound of formula (2) within the range of 1:20 to 1:50. Complex herbicide.