JPS6379804A - Herbicidal composition for paddy field - Google Patents

Abstract

PURPOSE:To obtain the titled composition, containing N-(2,4-difluorophenyl)-2-(3- trifluoromethylphenoxy)-nicotinamide and a specific pyrazole compound as active ingredients and capable of exhibiting effects in a small dose of chemical without giving phytotoxicity to paddy rice. CONSTITUTION:A herbicidal composition containing N-(2,4-difluorophenyl)-2-(3- trifluoromethylphenoxy)-nicotinamide and 4-(2,4-dichloro-3-methylbenzoyl)-1,3- dimethyl-5-(p-methylphenacyloxy)pyrazole at 1:10-40 weight ratio. The composition is capable of controlling a wide range of grass species in a small dose of chemical in which effects are not exhibited by independent use of each ingredient. Furthermore, controlling effects are sustained for a long period without permitting post-emergence of weeds. The effect application amount is 0.5-2.5kg/ha expressed in terms of the amount of the active ingredients. The use period is optimally 1-6 days after transplanting.

Description

[Detailed description of the invention] Technical field The present invention relates to a herbicidal composition for paddy fields.

By using two specific compounds as active ingredients, the herbicide composition of the present invention can be used at any time from immediately after rice planting to the peak of weed emergence to effectively target a wide range of annual and perennial weed species. It shows a good pesticidal effect and does not cause any chemical damage to paddy rice.

BACKGROUND OF THE INVENTION At present, a large number of herbicides are in practical use for paddy fields, and they are widely used as single agents or as mixtures containing two or more components.

However, although these agents are relatively effective against perennial weeds, their effectiveness against perennial weeds is insufficient;
Therefore, perennial weeds have been rapidly increasing in recent years.

These perennial weeds come in many varieties, grow and reproduce vigorously, and persist for long periods of time, making them extremely difficult to control.
The objective cannot be achieved by spraying herbicides twice, and the current situation is that the same or different herbicides are usually sprayed repeatedly. Such repeated use of herbicides not only requires a great deal of labor, but also causes undesirable problems such as residues in the soil and crops due to large amounts of herbicides being applied.

PRIOR ART The compounds used as active ingredients of the herbicidal composition of the present invention are known. For example, N-(2,4-sifolophenyl)-2-(3-)lifluoromethylphenoxy)-nicotinamide (hereinafter sometimes abbreviated as compound A) is disclosed in JP-A-57-118568. In the official gazette, etc., 4-
(2,4-dichloro-3-methylbenzoyl) -1,
3-dimethyl-5-(p-methylphenacyloxy)pyrazole (hereinafter sometimes abbreviated as compound B) is disclosed in JP-A-57-72903 and the like.

However, when each of these compounds is used alone, the grass species that can be controlled are limited and the efficacy is not sufficient. For example, Compound A is effective against annual weeds, but less effective against perennial weeds C2.

Compound B is mainly effective against broad-leaved weeds, but it is insufficiently effective against some perennial narrow-leaved weeds such as Japanese cyperus and black-leaved weed.

SUMMARY OF THE INVENTION The present inventors have investigated mixtures of various herbicides in order to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved for the first time by the herbicidal composition of the present invention, which uses a combination of specific herbicides. This was confirmed and the present invention was completed.

That is, the present invention provides N-(214-difluorophenyl)-
2-(3-)lifluoromethylphenoxy]-nicotinamide and 4-(2,4-dichloro-3-methylbenzoyl)-1,3-dimethyl-5-(p-methylphenacyloxyfpyrazole) An object of the present invention is to provide a herbicide composition for paddy fields, which contains as an active ingredient.

Effects of the Invention The herbicide composition of the present invention not only complements each other against weeds that are difficult to control using each of the active compounds alone, but also suppresses weeds at such low doses that each active compound alone cannot control the weeds. - It exhibits an appropriate herbicidal effect on a wide range of grass species, including hand weeds and perennial weeds, and does not cause any chemical damage to paddy rice.

Moreover, the herbicidal effect lasts for a long time and does not allow weeds to grow later.

These excellent effects clearly indicate the existence of a specific and strong synergistic effect between Compound A and Compound B, and are completely unexpected effects that were not observed in conventional mixtures. You could say that.

Detailed Description of the Invention The herbicide composition for rice fields of the present invention exhibits a strong synergistic effect in a wide range of composition ratios, but the mixing ratio of each active ingredient is usually 5 to 5 parts by weight of compound B to 1 part by weight of compound A. 100
Parts by weight, preferably 10 to 40 parts by weight.

The effective application amount of the composition of the present invention varies depending on the area to be controlled, the type of weed, the density of occurrence, etc., but the amount of the mixed active ingredient is 0.1 to 10 kF per ha, preferably 0.5 to 10 kF per ha.
It is 2.5 kF.

The timing of use of the herbicide composition of the present invention can be arbitrarily selected from a wide range from 7 days before transplanting paddy rice to 15 days after transplanting paddy rice. Among these, the highest effect can be obtained if the weeds are treated at the early stage of emergence (1 to 6 days after transplanting).

When applying the composition of the present invention as a herbicide, a suitable carrier is generally used, such as a solid carrier such as clay, talc, bentonite, or diatomaceous earth, or water, alcohols (methanol, ethanol, etc.), aromatic R-hydrogenides ( It can be applied by mixing with known liquid carriers such as benzene, toluene, xylene, etc.), chlorinated hydrocarbons, ethers, ketones, esters (ethyl acetate, etc.), and acid amides (dimethylformamide, etc.). can.

Furthermore, if desired, commonly used emulsifiers, dispersants, suspending agents, penetrating agents, spreading agents, stabilizers, etc. are added to form granules, emulsions,
Any formulation such as wettable powders or sol formulations can be used for practical purposes, but it is preferable to disperse the formulation as granules using a rotary granulator, power sprayer, etc., as this is the simplest and most effective method. ing.

In addition, if necessary, it may be used in combination with other agents such as fungicides, insecticides, plant preparation agents, synergists, etc. during formulation or spraying.

EXPERIMENTAL EXAMPLES Formulation examples and test examples are listed below to further specifically explain the present invention.The "parts" used in C2 in the examples are based on weight.

Formulation Example 1 (granules) 23 parts of Compound A, 0.2 parts of Compound B, 33 parts of bentonite, 59.8 parts of clay, 2 parts of dodecylbenzenesulfonate, and 2 parts of sodium ligninsulfonate were uniformly mixed. Formulation Example 2 (Emulsion) 216 parts of compound A, 822 parts of compound, polyoxyethylene Alkyl allyl ether: 8 parts, 28 parts of lucium 7 silbenzenesulfonate, 66 parts of a mixture of equal amounts of xylene and cyclohexanone were mixed and homogenized to obtain an emulsion. Test Example 1 (Treatment at the time of weed germination) Paddy soil and chemical fertilizer were placed in a 200 cd Wagner pot, and an appropriate amount of water was added and thoroughly stirred to make it flooded.To this, two two-leaf rice seedlings, each one grown in advance in a greenhouse, were added. 2 plants of Bot 11 were transplanted as a seedling, and seeds of Novie and Hotarui were sown.Furthermore, a certain amount of each of tubers of Mizugaya cypera and Urikawa were planted, and then transplanted into paddy rice 3.
After 1 day, a predetermined amount of the test compound was treated with granules (formulated according to Formulation Example 1). Table 1 shows the results of investigating the herbicidal effect and the degree of chemical damage to paddy rice after 30 days of chemical treatment. In addition, the herbicidal effect on each grass species and the degree of paddy rice damage in the table are 6 from rOJ to "5" according to the following guidelines.
It is represented by a numerical value of the stage and a sign of 6 stages from "=" to rXJ.

Table 1: Fist seal] "Oza" = Product name [A mixed herbicide containing as active ingredients butachlor 3.5, manufactured by Monsanto, and 7% naproanilide, manufactured by Mitsui Toatsu Chemical Industries. Mitsui Toatsu Chemical T! [Manufactured by Amm] These results show that the composition of the present invention can control various weeds at an extremely lower dose than when each active ingredient is used alone. Furthermore, it is clear that the purpose can be fully achieved with less than half the amount of active ingredient applied per unit area compared to general commercial preparations.

Test Example 2 (Effect of extending the period of use by mixing) Same as Test Example 1 except that the weed species were 2 grasses of wild grass and firefly.
Each drug (granule) was treated with the pot (granules) tabulated on a daily basis, and the herbicidal effect was determined using the same criteria as Test Example 1 in a pot with a burst diameter of 40.The results are shown in Tables 2 and 2. Table-3
Shown below.

Table 2 (Effect of extending the period of use against novia) Table 3 (These results against fireflies indicate that the active ingredients of the present invention work synergistically to significantly extend the period of weeding. It is.

Test Example 3 (Field Test) A paddy field that was planted according to the usual farming method was planted using a ridge sheet (Shin-Etsu Chemical Exhibition: trade name ``Azenami'') so that each section had a size of 10i (4 squares x 2.5 g). 5 days after rice planting, each chemical shown in Table 4 was treated using granules. After 40 days of chemical treatment, the herbicidal effect and paddy rice damage were evaluated according to the same criteria as Test Example 1 while maintaining normal management. was determined.

The results are shown in Table 41. All weeds were naturally occurring, except for the sowing of wildflower seeds.

Table 4) R Shoron MJ = Trade name Mixed herbicide containing GNP 9% manufactured by Mitsui Toatsu Co., Ltd. and Daimron '71 manufactured by Showa Denko Co. As shown by the results of Test Examples 1 to 3, the present invention The herbicide composition can effectively control various weeds with an extremely low dosage due to the excellent synergistic action of each active ingredient, and is extremely useful in agriculture.

Claims (1)

[Claims] (1) N-(2,4-difluorophenyl)-2-(3-
trifluoromethylphenoxy)-nicotinamide and 4-
(2,4-dichloro-3-methylbenzoyl)-1,3
- Dimethyl-5-(p-methylphenacyloxy)pyrazole as an active ingredient.