JPS6116244B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to 2,4-dichloro-3'-carbomethoxy-4'-nitrophenyl ether (hereinafter referred to as "compound").
(1)) or 2,4,6-trichlorophenyl-3'-carbomethoxy-4'-nitrophenyl ether and 2-methyl-4-chlorophenyl-
3'-carbomethoxy-4'-nitrophenyl ether (hereinafter referred to as "compound (2)") and 2-methyl-4
- Chlorphenoxyacetic acid (hereinafter referred to as "Compound A"). A feature of the herbicide according to the present invention is that, by mixing herbicides with different herbicidal activities, the herbicide has recently spread explosively and become extremely difficult to kill, making control measures a serious issue in various places. It exhibits an extremely high synergistic herbicidal effect against the perennial weed Prunus elegans. Conventionally, 2,4-dichlorophenoxyacetic acid, pentachlorophenol, 2,6-dichlorobenzonitrile, 2,4-pis(isopropylamino)-
6-methylthio-1,3,5-triazine,
2,4-Dichlorophenyl-4'-nitrophenyl ether, 2,4,6-trichlorophenyl, -
Many herbicides for rice fields, such as 4'-nitrophenyl ether and parachlorobenzyl N,N-diethylthiol carbamate, have been developed and widely used. Nowadays, the use of herbicides that are toxic to humans, toxic to fish, and highly phytotoxic has been severely restricted, and in their place, safe and extremely effective herbicides against weeds such as barnyard grass and grasshopper are being developed one after another. , the use of herbicides has made a significant contribution to the agricultural labor shortage. However, existing herbicides have almost no herbicidal activity against the perennial weed, which has recently become a problem in many areas, and when other weeds are removed, mutual competitive effects are eliminated. Urikawa spreads and flourishes explosively. Urikawa sprouts from tubers in early spring, sends out underground stems, and proliferates, and the number of overwintering tubers that year grows from one in spring to about 750 by the end of autumn, and as many as 550,000 the following year.
Tubers tend to float when paddy fields are filled with water in spring and tilled.
If one tuber invades in early spring, if growing conditions are good, three years later there will be more than 400 million tubers. Since interest in Urikawa arose in Setouchi a few years ago, it has now invaded most prefectures across Japan.
As it causes tremendous damage to rice crops and is rapidly growing, there is an urgent need to develop a chemical that can not only control weeds such as barnyard grass and Japanese grasshopper, but also highly effective control of weeds. It is requested. The purpose of the present inventors is to develop a drug that has an appropriate herbicidal effect on the hard-to-get rid of Prunus elegans, is non-toxic to humans and fish and shellfish, and is safe and harmless to crops. Many compounds were tested. As a result, it was found that a herbicidal composition containing compound (1) or compound (2) and compound A as active ingredients had extremely high herbicidal activity against paddy field grass, and that the two drugs mutually increased the herbicidal efficacy. It has been found that these compounds can exhibit synergistic herbicidal effects. Compound (1) or compound (2) has an extremely high control effect on the grass weed grass grass weed before and after emergence, as well as most annual broad-leaved weeds, and is an excellent rice field herbicide with little chemical damage to transplanted rice. be. In addition, high herbicidal properties have been observed when the chemical is applied before the emergence of the perennial weed lily. However, in practice, there were problems such as phytotoxicity to paddy rice when a dosage sufficient to completely control Paddy was used. Compound A is also known to have an extremely high control effect on annual weeds of paddy rice, such as Prunus japonicus and Kikashigusa. In addition, although Compound A has a slight herbicidal effect on the perennial weed Cucumber, it is extremely difficult to control it with a single agent in practical terms. However, it is a drug that cannot be completely killed at regular doses. By applying Compound (1) or Compound (2) and Compound A as active ingredients, the present invention not only has a high herbicidal effect on grasshopper, Japanese azalea, Japanese millet, and Kikashigusa, but also controls conventionally difficult to control herbivores. It has a synergistic herbicidal effect that was unimaginable with conventional agents against the common weed. This fact in the present invention is a completely new finding. The blending ratio of the active ingredients used in the present invention is compound (1) or compound (2) in parts by weight (hereinafter referred to as parts).
1 part to 1/30th part of compound A
Although it is appropriate to mix 1 part, it is possible to make a more suitable mix if necessary. Furthermore, it can of course be used in combination with other herbicides, and can also be used as a labor-saving pest control agent if used in combination with fungicides, insecticides, plant regulators, fertilizers, etc. The above-mentioned compound is mixed with various carriers to form a form commonly used in agricultural chemicals, such as emulsions,
It can be formulated into granules, wettable powders, etc. As carriers used for this purpose, commonly used carriers include solid carriers such as talc, clay, and bentonite, and liquid carriers such as alcohols, benzene, xylene, acetone, and solvent naphtha. Furthermore, various auxiliary agents such as a spreading agent, an emulsifier, a wetting agent, and a fixing agent can be added as necessary. Next, some examples of the herbicide composition of the present invention will be shown, but the present invention is not limited to the following examples. Example 1 Granules 7 parts of compound (2), 0.7 parts of compound A, bentonite
10 parts of sodium dodecylbenzenesulfonate, 2 parts of sodium dodecylbenzenesulfonate, and 80.3 parts of clay were mixed to form granules using a granulator. Example 2 Emulsion 18 parts of compound (2), 1.5 parts of compound A, 31 parts of xylene
parts, 42.5 parts of acetone and polyoxyethylene)
Seven parts of nil phenyl ether were uniformly mixed to form an emulsion. Example 3 Granules 9 parts of compound (1), 1.4 parts of compound A, 2,4-bis(ethylamino)-6-methylthio-1,3,5-
2 parts of triazine, 8 parts of bentonite, 2 parts of sodium dodecylbenzenesulfonate, and 77.6 parts of clay were mixed and made into granules using a granulator. Next, test examples will be shown regarding the herbicide composition according to the present invention. Test Example 1 Test for control efficacy against Urikawa As a test method, a 1/5000 are size Wagner pot was filled with alluvial clay paddy soil, and 10 Urikawa tubers per pot were transplanted to the emerging layer, and the water depth was 3 cm. I kept it. Thereafter, a predetermined amount of the test chemical was added dropwise immediately before the appearance of swelling.
This test was conducted using a three-pot system at one concentration. In the investigation, on the 30th day after treatment with the chemical, the remaining weeds were extracted and their dry weight was measured, and the weeding rate (%) was calculated from the average weight using the formula below. Weeding rate = (1 - average dry weight of treated area/average dry weight of untreated area) x 100 The results are shown in Table 1.

【table】

[Table] Test Example 2 As a test method, test plots were created in a rice field with each plot having a size of 10 m ² , and each plot was seeded with a certain number of tubers (100) and a certain amount of Konagi, Japanese millet, Kikashigusa, and Matsubai seeds. It was mixed into the soil surface layer during puddling. Rice was then planted while keeping the water depth at 3 cm. On the seventh day, granules of the test drug were prepared according to the example and sprayed. In the investigation, surviving weeds were pulled out on the 30th day of chemical treatment and their dry weight was measured. The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1 2,4-dichlorophenyl-3'-carbomethoxy-4'-nitrophenyl ether or 2,
4,6-Trichlorophenyl-3'-carbomethoxy-4'-nitrophenyl ether and 2-methyl-
4-Chlorphenoxyethyl acetate.