JP2549142B2 - Herbicide composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a herbicidal composition effective for controlling weeds in paddy fields. More specifically, the present invention provides A. (±) -2-exo- (2-methylbenzyloxy) as an active ingredient.
-1-methyl-4-isopropyl-7-oxabicyclo [2.2.1] heptane (hereinafter referred to as synmethrin) and B. (RS) -2-bromo-N- (α, α-dimethylbenzyl) -3, The present invention relates to a mixed herbicide composition containing 3-dimethylbutyramide (hereinafter referred to as bromobutide).

[Prior Art and Problems to be Solved by the Invention] (±) -2-exo- (2-methylbenzyloxy)
-1-Methyl-4-isopropyl-7-oxabicyclo [2.2.1] heptane is a compound having the following structure, It is known by the general name Symmethrin.

Its production method, herbicidal properties are described in JP-A-58-110591, and the effective herbicidal action with a very small amount of treatment against monocotyledonous weeds such as Poaceae, Cyperaceae, Omodaka family, Hydrangeaceae family. Have. For example, at the time of germination, the most sensitive Nobie is effective for herbicidal effects at a treatment amount of only 10 g per hectare. In addition, a treatment amount of 20 g / ha for 1.5 leaf nobies, 45 g / ha for 2.0 leaf nobies, 60 g / ha for 2.5 leaf nobies, and 90 g / ha for 3.0 leaf nobies is effective.

The stability to paddy rice varies depending on the weather, soil conditions, growing condition of paddy rice, etc., but the limit is 60 to 120 g per hectare.

On the other hand, (RS) -2-bromo-N- (α, α-dimethylbenzyl) -3,3-dimethylbutyramide is a compound having the following structure, It is a herbicide for paddy rice known by the general name bromobutide.

The manufacturing method and herbicidal properties of bromobutide are described in JP-B-56-43455.
It is effective in controlling weeds such as cyperaceae, water mallow, stiltaceae, lythrumaceae, scorpionaceae, and mosquito family, and is particularly effective against firefly in cyperaceae, at a relatively low dose. Has a good herbicidal effect. For example, 100-200 g /
The effective herbicidal effect is demonstrated by the treatment amount of 250 g / ha for hectare, 1.0-1.5 leaf stage firefly, and 500 g / ha for 2.5-3.0 leaf stage. However, there was a tendency that the effect was decreased for the common leaf miller with advanced leaf age.

Recent advances in herbicides have led to the development of highly selective herbicides, but on the other hand, many types of weeds require control, and it is necessary to mix several herbicides to control them all. Come on. As a result, the amount used increases, which causes a problem of increased drug damage to crops. Further, since mixed use of herbicides often causes a synergistic effect on phytotoxicity to crops, it is necessary to perform a thorough examination on the mixed formulation of herbicides.

[Means for Solving the Problems] The inventor has shown an effective control action against many kinds of weeds with a small dose, and continued to develop a mixed herbicide with little phytotoxicity. By applying cinmethrin and bromobutide in a specific ratio, a very significant synergistic effect was obtained for grass and cyperaceae weeds, far lower than the doses expected from the effects of cinmethrin and bromobutide alone. It was found that the effects of the above-mentioned two kinds of single agents can be exhibited by mixing the doses. Moreover, since no synergistic effect of phytotoxicity on paddy rice was observed, it was successful to reduce phytotoxicity to paddy rice by low-dose treatment with the mixed herbicide composition.

That is, the present invention relates to A. (±) -2-exo- (2-methylbenzyloxy)
-1-methyl-4-isopropyl-7-oxabicyclo [2.2.1] heptane (cinmethrin) and B. (RS) -2-bromo-N- (α, α-dimethylbenzyl) -3,3-dimethyl A herbicidal composition comprising butyramide (bromobutide) as an active ingredient.

The mixing ratio of synmethrin and bromobutide in the herbicidal composition of the present invention is preferably 0.5 to 200 parts by weight, and particularly preferably 1 to 20 parts by weight, relative to 1 part by weight of synmethrin.

The most suitable method for mixing simmethrin and bromobutide is to formulate and use both as a mixed granule, but they can also be mixed and used in the form of a wettable powder, a paste or the like.

Granules can be manufactured by a known method. For example, it is produced by mixing the active ingredients of cinmethrin and bromobutide with a surfactant, a solid carrier, a binder and the like, and by a coagulation method, an impregnation method or the like. Nonionic as a surfactant,
Any of cationic, anionic and zwitterionic can be used. Examples thereof include alkyl sulfate ester, alkylaryl sulfonate, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid alcohol ether and the like. Examples of the solid carrier include talc, clay, bentonite, acid clay, pyrophyllite, calcium carbonate, calcite, ammonium sulfate and the like.

The amount of active substance in the granule is 0.1-5% by weight, preferably
It is in the range of 0.2 to 2.2% by weight.

As a treatment period of the herbicidal composition of the present invention, the pre-emergence of weeds to the initial growth stage is suitable, and it is desirable to treat the herbicide composition from 0 to 3.0 leaf stage. Further, the period of 3 to 20 days after transplanting the rice seedlings is suitable, and the period of 7 to 14 days is most suitable.

The dose of the herbicidal composition used is 24 to 60 g of synmethrin / hectare, 45 to 600 g / ha of bromobutide, especially 24 to 30 g / ha of synmethrin, 45 to 600 g of bromobutide.
It is preferably in the range of / ha.

[Effects of the Invention] The herbicidal composition of the present invention takes advantage of the characteristics of its constituents, simmethrin and bromobutide, to prevent
Not only it has an excellent control effect on many important weeds in paddy fields such as Nobie, firefly, konagi, cypress, pine nuts, etc., it also exerts a synergistic herbicidal effect by mixing, and shows remarkable activity compared to the case of using each alone. . Therefore, the amount of herbicide used can be greatly reduced, and the phytotoxicity to crops can be reduced.

In addition, the herbicide composition is extremely safe because no increase in phytotoxicity to paddy rice is observed.

The present invention is further described below with reference to formulation examples and test examples.

Formulation Example 1 Synmethrin 0.1 part by weight (compound 100% conversion) Bromobutide 1.5 parts by weight (〃) Neogen powder 1.0 〃 (Daiichi Kogyo Seiyaku Co., Ltd. anionic surfactant) Bentonite 50.0 〃 Talc 47.4 〃 After adding water and kneading, the mixture was granulated and dried to obtain granules.

Formulation 2 Synmethrin 2.0 parts by weight (compound 100% conversion) Bromobutide 40.0 〃 (〃) Newcalgen NX405H 5.0 〃 (Takemoto Yushi Co., Ltd. surfactant) Carplex 10.0 〃 (Adsorbent) Clay 43.0 〃 To obtain a wettable powder.

Test Example 1 (Synthesulin and bromobutide synergistic herbicidal effect on the sea urchin) [Test method] 10 pre-germinated seeds of the sea bream were sown in a pot with an area of 1 / 10,000 are and sown to a depth of 5 mm and kept in a paddy field at a depth of 3 cm. It was

A herbicidal composition solution was prepared by dissolving 7 kinds of herbicidal compositions of cinmethrin and bromobutide in acetone and diluting them with an equal amount of water. Furthermore, regarding the composition solution of each mixing ratio, this was mixed with water / acetone equivalent mixed solution.
A solution having a total of 5 kinds of concentrations diluted in 4 steps to a concentration of 0.75 was prepared.

On the 12th day after seeding, when the Pinus striata reached the 2-leaf stage, 10 ml of the drug solution was dropped into each pot with a pipette. The basic processing amount (processing amount when the dilution ratio is 1) and the dilution ratio of the chemical solution of each mixing ratio are as follows.

The test was repeated three times for each mixing ratio and each concentration of the drug solution.

After the treatment, if necessary, macroscopic observation was performed, and after two weeks, the number of Taeniubia and live weight were measured, and for the treatments at each mixing ratio, the average values of 5 concentrations and 3 repeated live weights are shown in Table 1. Indicated.

Table 1 shows that the herbicidal composition of the present invention has a remarkable herbicidal effect on Taenia cinerea and has a very large synergistic effect as compared with the case where singmethrin and bromobutide alone are treated.

In addition, from the results of the treatment with the herbicidal composition of each mixing ratio, the treated amount (g / ha) of each component in the herbicide composition that achieved 80% growth inhibition of the seaweed was plotted for each mixing ratio. The isoeffect curves of Figure 1 were obtained. Since bromobutide has almost no control effect on the northern locust, theoretically, even if the treatment amount of bromobutide was increased, the treatment amount of synmethrin did not change. Therefore, the dotted line in FIG. 1 is a theoretical isoeffect curve. From this, it can be seen that in the herbicide composition of the present invention, the amount of synmethrin used can be significantly reduced by the addition of bromobutide.

Test Example 2 (Synthesulin and bromobutide synergistic herbicidal effect and phytotoxicity to paddy rice) [Test method] Ten seeds of Tainubie seeds pre-germinated were sown to a depth of 5 mm in a pot having an area of 1 / 10,000 are.

Three days after that, 3 seedlings of paddy rice that grew on 2.5 leaves were taken as 1 plant, and 3 plants per pot with an area of 1 / 10,000 are are 1.0 cm deep.
Transplanted. The water depth was kept at 3 cm.

Ten days later, when the rice leaf reached the 2.0 leaf stage and the rice reached the 7th day after transplanting, it was treated with the herbicidal composition solution prepared in the same manner as in Test Example 1.

 However, the basic processing amount and mixing ratio are as follows.

The dilution ratio used was the same 5 concentrations as in Test Example 1, and the test was 3
Made in iteration.

If necessary, perform visual observation, and after 2 weeks of drug treatment,
The fresh weight of rice and paddy rice was measured. For the treatment with each mixing ratio, the average value of 5 concentrations and 3 replicate live weights
Shown in the table.

From the results shown in Table 2, bromobutide, which has almost no effect on Taenia chinensis when treated alone, effectively acts in the mixed composition with synmethrin, and the herbicidal composition of the present invention shows that synmethrin and bromobutide are effective. It can be seen that the herbicide composition is extremely safe against paddy rice as in the case of the single treatment.

Test Example 3 (Synthesulin and bromobutide synergistic herbicidal effect on firefly) [Test method] Approximately 400 seeds of firefly were sown on the soil surface in a Wagner pot with an area of 1 / 5,000 are and covered with a thickness of about 3 mm. did.

One day later, three paddy rice seedlings that had grown to 2.5 leaves were used as one strain, and three strains were transplanted to a depth of 1.0 cm per pot having an area of 1 / 5,000 are.

The depth of water was maintained at 3 cm at all times, and the herbicide composition solution prepared in the same manner as in Test Example 1 was used for the chemical treatment at the 1.0-1.5 leaf stage of firefly and 6 days and 9 days after transplanting rice. However, the treatment amount and the mixing ratio were the following 6 kinds, the concentration was only 1 kind, and the test was repeated 4 times for each mixing ratio.

The survey was conducted by visual observation as needed, and the paddy rice was measured for plant height and number of stems every 7 days. In the final survey, the fresh weight (g) of firefly and paddy rice was measured 21 days after the treatment. The average fresh weight (g) of 4 repetitions by the treatment at each mixing ratio is shown in Table 3 as a ratio to the fresh weight (g) of the untreated group.

From the results shown in Table 3, the herbicidal composition of the present invention has a synergistic herbicidal effect on firefly, while having little phytotoxicity to paddy rice, and having a very high stability. It is shown.

[Brief description of drawings]

FIG. 1 is an isoeffect curve obtained by the mixed treatment of synmethrin and bromobutide in suppressing the growth of 80% of the sea urchin.

Claims (1)

(57) [Claims] 1. A. (±) -2-exo- (2-methylbenzyloxy) -1-methyl-4-isopropyl-7-oxabicyclo [2.2.1] heptane and B. (RS) -2- A herbicidal composition comprising bromo-N- (α, α-dimethylbenzyl) -3,3-dimethylbutyramide as an active ingredient.