JPH01242506A - Herbicide composition - Google Patents

Abstract

PURPOSE:To obtain a herbicide showing extremely excellent synergistic effects on gramineous weeds and cyperaceous weeds, capable of reducing phytotoxicity to crops because of enabling of remarkable reduction in amount of herbicide, containing cinmethylin and bromobutide in a specific ratio. CONSTITUTION:A herbicide composition obtained by blending 1 pt.wt. cinmethylin shown by formula I with 1-20 pts.wt. bromobutide shown by formula II, surfactant, solid carrier, binder, etc. and made into granules by aggregation method or impregnation method or into a form such as wettable powder or paste. The herbicide has not only excellent effects on weeds in paddy fields such as Echinochloa oryzicola Vasing, Echinochloa crus-galli Beauv. var. praticola Ohwi., monochoria, water nutgrass, slender spikerush, etc., but also can reduce the amount of herbicide because of synergistic effects by blending. Treatment period of the herbicide is suitably prior to germination to early stage of growth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a herbicidal composition effective for controlling weeds in rice fields. More specifically, the present invention uses A, (±)-2-echin-(2-methylbenzyloxy)-1-methyl-4-isopropyl-7-oxabicyclo[2,2,11 hebutane (hereinafter referred to as synmethrin) as an active ingredient. It is called.

) and B, (R3)-2-ClMoN-(,,,-dimethylbenzyl)-3,3-dimethylbutyramide (hereinafter referred to as bromobutide).

[Problems to be solved by the conventional technology and invention J (±
)-2-exo-(2-methylbenzyloxy)-1-
Methyl-4-isopropyl-7-oxabicyclo[2,
2,l] Hebutane is a compound having the following structure and is known by the generic name synmethrin.

Its manufacturing method and herbicidal properties are described in JP-A-58-110591, and it has an effective herbicidal effect on monocotyledonous weeds such as Poaceae, Cyperaceae, Omodacaceae, and Polygonaceae with an extremely small amount of treatment. have For example, a treatment amount of only 10 g per hectare is effective against weeds, which are the most susceptible, at the time of germination. Also, 20g/ha for wildflowers with 1 and 5 leaves, 45g/ha for wildflowers with 2.0 leaves, 60g/ha for wildflowers with 2.5 leaves, and 90g/ha for wildflowers with 3.0 leaves.
/Effective with a throughput of Hekucool.

Furthermore, the safety for paddy rice varies depending on the weather, soil conditions, growth conditions of paddy rice, etc., but the limit is 609 to 120 g per hectare.

On the other hand, (R5)-2-bromo-N-(σ,σ-dimethylbenzyl)-3,3-dimethylbutyramide is a compound having the following structure, and is a herbicide for rice rice commonly known as promobutide. It is.

The manufacturing method and herbicidal properties of bromobutide were published in Japanese Patent Publication No. 56-434.
It is described in Publication No. 55 and is effective in controlling weeds such as Cyperaceae, Cyperaceae, Cyperaceae, Cyperaceae, Cyperaceae, and Omodaceae, and is relatively effective against firefly of the Cyperaceae family. It has an effective herbicidal effect at low doses.

For example, for firefly in the germination period, 100 to 200 y/
ha, ■, 2 for firefly at 0-1.5 leaf stage
50g/ha, 500g at 2.5-3.0 leaf stage
Demonstrates effective weed control at a treatment rate of /ha.

However, there was a tendency for the effectiveness to decrease against Japanese millet with advanced leaf stages.

In recent years, remarkable advances in herbicides have led to the development of highly selective herbicides, but on the other hand, there are many types of weeds that need to be controlled, and in order to control them all, it is necessary to mix several types of herbicides. It becomes.

Therefore, the amount used increases, leading to the problem of increased phytotoxicity to crops. In addition, the use of mixed herbicides often causes synergistic effects on crops, so careful testing is especially necessary for mixed formulations of herbicides.

[Means for Solving the Problems] As a result of continued development of a mixed herbicide that exhibits effective control action against many types of weeds with a small dose and has little chemical damage, the inventor has found that:
Surprisingly, by applying the above-mentioned synmethrin and bromobutide in a mixed manner at a specific ratio, a very significant synergistic effect was obtained against grass and cyperaceous weeds, which is expected from the effect of synmethrin and bromobutide alone. It has been found that the effects of the above-mentioned two types of single agents can be exhibited by mixing them in a much lower amount than the amount used. Moreover, since no synergistic effect of chemical damage to paddy rice was observed, we succeeded in reducing the chemical damage to paddy rice by low-dose treatment with a mixed herbicide composition.

That is, the present invention provides A, (±)-2-equin-(2-methylbenzyloxy)-1-methyl-4-ingrobyl-7-oxabisic-[2,2,1]hebutane (synmethrin), and B, (R5 )-2-Bromo-N-(a,a-dimethylbenzyl)-3,3-dimethylbutyramide (bromobutide) as an active ingredient.

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

The most suitable way to mix synmethrin and bromobutide is to formulate and use them as mixed granules,
They can also be mixed and used in the form of a paste or the like.

Granules can be manufactured by a known method. For example, active ingredients such as synmethrin and bromobutide are mixed with a surfactant, a solid carrier, a binder, etc., and produced by aggregation method, impregnation method, etc. As the surfactant, any of nonionic, cationic, anionic, and amphoteric ionic surfactants can be used. For example, alkyl sulfates, alkylaryl sulfonates, polyoxyethylene fatty acid esters,
Examples include polyoxyethylene fatty acid alcohol ether. Solid carriers include talc, clay,
Examples include bentonite, acid clay, pyrophyllite, calcium carbonate, calcite, and ammonium sulfate.

The amount of active substance in the granules ranges from 0.1 to 5% by weight, preferably from 0.2 to 2.2% by weight.

The suitable period for treatment with the herbicide composition of the present invention is from before the germination of weeds to the early stage of growth, and it is desirable to apply the herbicide composition at the 0 to 3.0 leaf stage. Further, a period of 3 to 20 days after transplanting paddy rice seedlings is suitable, and a period of 7 to 14 days is particularly optimal.

The dosage of the herbicide composition used is 60g of Shinmeth 9F24F.
Preferably, the amount of bromobutide is 5 to 60 g/ha, and the amount of bromobutide is 45 to 6009 g/ha.

[Effect of the invention 1] The herbicidal composition of the present invention takes advantage of the characteristics of its constituent components, synmethrin and bromobutide, and has excellent control effects against many important weeds in paddy fields, such as Japanese grasshopper, Japanese field grass, bulrush, Japanese grasshopper, Japanese grasshopper, and Japanese grasshopper. Not only do they have a synergistic herbicidal effect when mixed, but they exhibit remarkable activity compared to when each is used alone. Therefore, it is possible to greatly reduce the amount of herbicides used, and it is possible to reduce chemical damage to crops.

Furthermore, since no increase in chemical damage to paddy rice was observed, it is an extremely safe herbicide composition.

The present invention will be further explained with reference to formulation examples and test examples below.

Formulation Example 1 Synmethrin 0.1 parts by weight (calculated as 100% compound) Bromobutide 1.5 parts by weight (〃) Neogen Powder 1. On (anionic surfactant manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) bentonite 50.0// talc 47.47/ was mixed, water was added, kneaded, and then granulated and dried to obtain granules. .

Formulation example 2 Synmethrin 2.0 parts by weight (calculated as 100% compound) Bromobutide 40.0 // ( //
) (Adsorbent) Clay 43.0// was thoroughly ground and mixed to obtain an irrigation agent.

Test Example I (Synergistic herbicidal effect of synmethrin and bromobutide on Japanese millet) [Test method 1 Ten pre-germinated seeds of Japanese millet are sown to a depth of 5 mm in a pot with an area of 1/10,000 are, and a paddy field with a water depth of 3 cm is planted. kept in condition.

A herbicide composition solution was prepared by dissolving seven herbicide compositions of synmethrin and bromobutide in acetone and diluting this with an equal amount of water.

Furthermore, the composition solutions of each mixing ratio were diluted in four stages with equal amounts of water/acetone to a concentration of 0.75 times each to prepare solutions with a total of five concentrations.

When the Japanese millet reached the two-leaf stage 12 days after sowing, 10 m12 of the chemical solution per pot was dripped with a pipette. The basic processing amount (processing amount in the case of dilution ratio I) and dilution ratio of the chemical solution at each mixing ratio are as follows.

The test consisted of 3 tests for each mixing ratio and each concentration of drug solution.
It was done iteratively.

After treatment, perform visual observation as necessary, measure the number and live weight of Japanese millet after 2 weeks, and calculate the average value of the fresh weight of 3 replicates at 5 concentrations for each treatment at each mixing ratio.
Shown in the table.

Table 1 shows that the herbicidal composition of the present invention has a remarkable herbicidal effect on Japanese millet compared to the single treatment of synmethrin and bromobutide, and has an extremely large synergistic effect.

In addition, from the results of treatment with herbicide compositions at various mixing ratios, the treatment amount (g/ha5) of each component in the herbicide composition that achieved 80% growth inhibition of Japanese millet was plotted for each mixing ratio. The iso-effect curve shown in Figure 1 was obtained.Since bromobutide has almost no control effect on Japanese millet, theoretically even if the amount of bromobutide treated increases, the amount of synmethrin treated will not change. Since the dotted line in FIG. 1 is a theoretical iso-effect curve, it can be seen that in comparison with this, in the herbicidal composition of the present invention, the amount of synmethrin used can be significantly reduced by adding bromobutide.

Test Example 2 (Synergistic herbicidal effect of synmethrin and bromobutide and phytotoxicity on paddy rice) [Test method] Ten pre-germinated seeds of Japanese millet were placed in a pot with a surface area of ml/10,000 are at a depth of 5 mm.
: Sown.

Three days later, three paddy rice seedlings that had grown to 2.5 leaves were transplanted to a depth of 1.0 cm per pot with an area of 1/10,000 are. The water depth is kept at 3cm in both cases.)
is.

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

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

The same 5 concentrations as in Test Example 1 were used as the dilution ratio, and the test was repeated three times.

Macroscopic observation was carried out as necessary, and fresh weights of Japanese millet and paddy rice were measured two weeks after the drug treatment. Table 2 shows the average live weight of 3 replicates at 5 concentrations for each treatment at each mixing ratio.

From the results in Table 2, it is clear that bromobutide, which is hardly effective against Japanese millet when treated alone, is effective in a mixed composition with synmethrin, and that the herbicide composition of the present invention is effective against synmethrin and bromobutide. It can be seen that the herbicide composition is extremely safe for paddy rice, as is the case with the single treatment.

Test Example 3 (About the synergistic herbicidal effect of synmethrin and bromobutide on firefly) [Test method 1 Approximately 400 herbicides were placed in a Wagner pot with an area of 115,000 are.
Granular firefly seeds were sown on the soil surface and covered with soil to a thickness of about 3 mm.

Three paddy rice seedlings that grew to 2.5 leaves after 1 day were designated as I plants, and 3 plants per pot with a surface of 1 t and 15,000 are were placed at a depth of 1.
．． It was transplanted at 0 cm.

The water depth was always maintained at 3 cm, and the plants were treated with a herbicide composition solution prepared in the same manner as in Test Example 1 at the 1.0 to 1.5 leaf stage of firefly and 6 and 9 days after transplanting paddy rice. However, the treatment amount and mixing ratio were the following six types, and the concentration was only one type.In each test, visual observation was performed as necessary, and the plant height and number of stems of rice were measured every 7 days. In the final investigation, fresh weights (9) of firefly and paddy rice were measured 21 days after treatment. Table 3 shows the average fresh weight (9) of four replicates of treatment at each mixing ratio as a ratio to the fresh weight (9) of the untreated group.

From the results in Table 3, the herbicide composition of the present invention has a synergistic herbicidal effect on firefly as well, while causing almost no chemical damage to paddy rice, indicating that it is an extremely safe herbicide composition. It is shown.

[Brief explanation of the drawing]

FIG. 1 is an iso-effect curve of the mixed treatment of synmethrin and bromobutide in inhibiting the growth of Japanese millet by 80%. Patent applicant Shell Chemical Co., Ltd.

Claims (1)

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