JPH07258012A - Herbicides and methods - Google Patents

Abstract

PURPOSE:To obtain a herbicide containing, as active ingredient, a mineral oil such as spindle oil or heavy white oil, directly applicable by its dripping onto a paddy field filled with water, little affecting the environment such as water quality and soil, also excellent in terms of the cost. CONSTITUTION:This herbicide contains, as active ingredient, a mineral oil such as spindle oil, heavy white oil, light white oil, mineral spirit, mineral turpentine, naphthenic oil, paraffin oil or machine oil for agrochemicals. This herbicide is effective on all kinds of weeds developed in a paddy field (esp. on rice weeds such as Echinochloa crus-galli), being esp. effective at the initial growing stage of weeds being in a sunk state as a whole. For example, in the case of Echinochloa crus-galli, it is highly effective at the growing stage of two-leaf period or earlier, never affecting the growth of rice as a useful crop. It is preferable that this herbicide be applied esp. after rice transplanting. This herbicide, which floats on water surface, can be excluded by removing the upper surface of a paddy field after weeding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a herbicide containing a mineral oil as an essential component and a herbicidal method for directly dripping the herbicide onto a paddy field under flooding.

[0002]

2. Description of the Related Art Heretofore, as a method for spraying herbicides in flooded sewage fields, granule spraying and emulsion stock solution spraying have been the mainstream because of their simplicity. In some cases, emulsions or wettable powders diluted with a large amount of water are used. The method of spraying is used.

Of these methods, the method of spraying granules is the most widely used because it is easy. However, the active ingredient in the granules is used in order to achieve a uniform spraying problem and a uniform and stable drug effect. The compounding ratio must be increased, which may lead to high cost and environmental pollution.

On the other hand, the undiluted solution spraying method of emulsion is as easy as the spraying of granules. However, if it is carried out after rice planting, the organic solvent contained in the emulsion causes phytotoxicity to the seedling rice, so that it is sprayed. Has many problems, including that it must be done before planting rice, and that subsequent flooding work during rice planting may cause environmental pollution due to runoff to the surrounding waters around the paddy field.

Further, in the method of diluting an emulsion or a wettable powder in a large amount of water and spraying it, a great deal of labor is required when preparing a spraying liquid, a problem due to an organic solvent in the emulsion, and a wettable powder in the wettable powder. It has been pointed out that powdering may occur during preparation of the spray liquid, which may impair the health of the worker.

For the purpose of solving the above-mentioned problems, in recent years, a method of directly dripping an undiluted solution of an aqueous suspension into a paddy field under flooding (Japanese Patent Laid-Open Nos. 62-45501 and 62-28950).
No. 2, JP-A-63-107901, JP-A-4-270.
No. 201, JP-A-4-270202) or a method in which an agent is rapidly dispersed on the surface of water by directly spraying an oily suspension on the surface of a flooded paddy field, and then dispersed in water. Formulations (JP-A-54-35216, JP-A-4-1)
8002, JP-A-4-21611, JP-A-4-21
612 and JP-A-4-21613). However, all of them have a problem in terms of cost because they contain the existing herbicide raw material, and since they are dispersed throughout the paddy water, they may cause water pollution and soil pollution.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems that such conventional herbicides and herbicidal methods have, and specifically, the environment such as water quality and soil. The object of the present invention is to provide a herbicidal agent and a herbicidal method which have a small influence on the plant and are excellent in cost.

[0008]

[Means for Solving the Problems] In view of the above situation, the inventors of the present invention have conducted extensive studies on a weeding method in which water is sprayed directly onto flooded paddy fields, and as a result, the water surface is rapidly spread and spread on the water surface. Floating, by using a herbicide that exerts a herbicidal effect on the surface of the water, it was found that the problems as described above can be solved, further found that mineral oil has such characteristics, the present invention based on these findings completed.

That is, the first invention of the present application is a herbicide characterized by containing mineral oil as an active ingredient.

A second invention of the present application is a weeding method characterized in that the above-mentioned herbicide is sprayed directly onto a paddy field under flooding.

The invention of the present application will be described in detail below.

The herbicide of the present invention contains mineral oil as an active ingredient, and does not contain any existing herbicide raw material.

The herbicide of the present invention has the property of rapidly spreading the water surface by dropping it in paddy water and continuously floating the water surface without being dispersed in the water.
In particular, when weeds such as Nobie are grown on the surface of the water and appear on the surface of the water, they adhere to plants and cause necrosis, which inhibits their extension to the surface of the water. It has a herbicidal effect. Leaves with sufficient adherence of this herbicide are necrotic on the surface of the water, and then the plant individual cannot grow on the water.However, even leaves that have not been necrotic on the surface of the herbicide due to insufficient adhesion of the herbicide on the surface of the water. It shows a symptom that it withers and then withers. Therefore, by applying this herbicide dropwise to one or several points on the surface of the paddy field without the worker entering the paddy field, the surface of the water can be spread quickly and over a very wide range, and then the surface of the water can be kept floating and long-lasting. Exhibits herbicidal effect over a period of time. Conventional liquid formulations (emulsions, wettable powders, aqueous suspensions, etc.) are diluted with a large amount of water at the time of application,
Furthermore, since it is sprayed using a sprayer, a large amount of labor is required when applying it over a wide area. The present invention is a very epoch-making thing which eliminates such complicated work at the time of spraying and reduces labor. Already, several methods of dropping an aqueous suspension or oily suspension directly into paddy water have been reported (the above-mentioned publication), but these are the types that are finally dispersed in paddy water. On the other hand, since the herbicide of the present invention permanently floats on the water surface and exerts an effect, it is possible to recover by increasing the amount of water in the paddy field after the weeding and allowing only the upper layer to flow out of the paddy field. is there. In addition to having these characteristics, the application amount is extremely small, so that it has very little effect on the environment.

Mineral oils that can be used in the present invention include spindle oil, heavy white oil, light white oil, mineral spirit, mineral terpene, naphthene oil, paraffin oil, machine oil for agricultural chemicals, and the like. It is not limited.

In addition to the above, various additives, if necessary,
For example, it does not make any difference to add and use a decomposition inhibitor, an antioxidant and the like.

The herbicide of the present invention exerts an effect on all weeds occurring in paddy fields, but is particularly effective on grass weeds such as Nobie. The growth stage of the plant to be weeded is not particularly limited, but it is particularly effective for the early growth stage in which the whole plant is still submerged in the paddy field. For example, if it is a Nobie, it has a great effect on the growth stage of 2 leaf stage or less. The herbicide of the present invention has no effect on the growth of rice, which is a useful crop in paddy fields.

When the herbicide of the present invention is applied to an actual paddy field, the application method is not particularly limited as long as it is a method capable of effectively controlling weeds, but it can be directly applied by spraying to a paddy field under flooded water. desirable.

The time of use of the herbicide of the present invention is not particularly limited, but it is preferable to use it after planting rice because it has an effect on seedlings submerged in water. When applying this herbicide drop-wise in paddy fields after planting, 1 per 1 a
It is desirable to apply 00 ml or more, preferably 200 to 500 ml dropwise. If the application rate is less than the above range, a sufficient herbicidal effect cannot be expected, but if the application rate is set within the above range, proper weeding is possible. for that reason,
Excessive application is not preferable in consideration of cost and the like.

[0019]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

Example 1 (Test of growth inhibitory effect on Nobie
Test) a) Relationship between leaf age and growth inhibition degree After growing seedlings of Nobie by using paddy soil in a pot of 1 / 10000a, and adding water thereto (in the case of about 2 leaf stage, almost the entire plant body) Will be submerged in water), and 10 μl of light white oil was added dropwise to each pot. At this time, in order to investigate the relationship between the leaf age and the growth inhibition degree of Nobie, the Nobie with different leaf ages (2 leaf stage, 1.5 leaf stage, 1 leaf stage,
Leaf stage) was used. For 3 weeks after the dripping treatment, the growth state of Nobie was compared and observed between the treated pot and the untreated pot. The untreated Nobie grew on the water, whereas the pots in which the whole plant was submerged in the treated pot adhered this herbicide on the water surface as they grew,
The extension above water was significantly inhibited. In addition, regarding the Nobie that had been growing above the water before the treatment, the part that had been submerged due to growth was damaged by the herbicide on the water surface,
After that, the phenomenon of withering was observed. At this time, in order to investigate the effect of this herbicide on the growth of rice, drop treatment was also performed on rice plants with different leaf ages, which were raised in the same manner as in Nobie, and the growth condition was observed.

Table 1 shows the results of determination of the growth inhibitory effect of the present herbicide on Nobies up to 3 weeks after the treatment. Also,
Table 2 shows the determination results of the degree of inhibition of growth of this herbicide on rice up to 3 weeks after the treatment.

The degree of growth inhibition was expressed as a percentage with 0% when there was no difference from the growth situation in the untreated pot and 100% when the growth was completely inhibited. Therefore,
As for Nobie, the pot in which the leaf age at the time of treatment was 2 leaves stage or less and the whole plant was submerged, the growth rate was 100% when all the plants in the pot were on the water surface when the degree of inhibition was 100%. It means that it could not extend upward and eventually became necrotic.

[0023]

[Table 1]

[0024]

[Table 2]

As described above, the herbicide according to the present invention was treated by the method of the example in an amount of 10 μl per 1 / 10000a, that is, 1
It was found that the application of 100 ml per a can considerably strongly inhibit the growth of Nobier in the submerged state at the 2nd leaf stage or below. In Table 1, it seems that the plants recover numerically, but this is because the adhesion of the chemicals on the water surface was not sufficient and the existence of the leaves recovered from damage was quantified. Complete control is possible if applied dropwise. It was also confirmed that this herbicide had no effect on rice growth. In addition, this herbicide spread the water surface immediately after dropping on the water surface and continuously floated on the water surface to exert its effect.

B) Relationship between dropping amount and growth inhibition degree In a pot of 1 / 10000a, seedlings of Nobie are grown to 1.5 leaf stage, thinned into 5 pots per pot, and water is added to submerge them. After that, a fixed amount of the herbicide in a) was dropped. Over the next 4 weeks, the growth state of Nobie was compared and observed between the treated pot and the untreated pot, and the relationship between the dropping amount and the growth inhibition degree was investigated. Process 4
Table 3 shows the determination results up to a week later.

The degree of growth inhibition was 0% when there was no difference from the growth condition of Nobie in the untreated pot, and all five plants were damaged by the herbicide spread on the water surface, and 100% when the elongation is completely inhibited
And expressed as a percentage. In addition, when the state of 100% continued, the water-like damage eventually spread and the whole plant was necrotic.

[0028]

[Table 3]

As described above, it was found that the growth of a plant damaged by the addition of 50 μl can be suppressed almost completely, although the growth can be sufficiently inhibited even with the addition of 10 μl per pot.

At this time, in order to investigate the relationship between the dropping amount of the herbicide and the growth inhibitory effect of rice, rice plants grown up to the 2.5 leaf stage in paddy soil of 1 / 10000a were also used to grow Similarly to the above, the pot was filled with water, the lower part from the second leaf was submerged, and then the dropping treatment was performed to observe the growth condition. Table 4 shows the determination results up to 4 weeks after the dropping treatment. The degree of growth inhibition was expressed as the same percentage as above.

[0031]

[Table 4]

As described above, it was revealed that the rice in which the upper part of the second leaf extends above the water surface is not affected even when 50 μl of the present herbicide is dripped per 1/10000 a. Therefore, when the herbicide is applied dropwise to a paddy field after rice planting, phytotoxicity to rice is not a problem.

Example 2 (Study on various mineral oils) In a pot of 1 / 10000a, seedlings of Nobie were grown up to 1.5 leaf stage, thinned to 5 plants per pot, and water was added to make them submerged. After that, 20 μl each of various mineral oils (light white oil, heavy white oil, spindle oil) were dropped. The relationship between the type of mineral oil and the degree of growth inhibition was examined in the same manner as above over the next 3 weeks. The judgment results are shown in Table 5. The growth inhibition degree was determined in the same manner as in Example 1.

[0034]

[Table 5]

As described above, it was found that all mineral oils have a growth inhibitory effect on Nobies, and they rapidly spread the water surface after being dripped on the water surface and continuously float.

[0036]

EFFECTS OF THE INVENTION By applying a small amount of the herbicide of the present invention directly to paddy field water, it becomes possible to control weeds in paddy fields with a chemical that spreads the water surface rapidly over a wide area. This herbicide is
Since it does not contain the existing active ingredient of chemical herbicides and continuously floats on the water surface, it can be eliminated by removing the upper layer of the paddy field after weeding, and has little impact on the environment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoko Tanabe 6 Umegaoka, Midori-ku, Yokohama-shi, Kanagawa Prefecture, Japan 2 Tobacco Inc. Plant Development Laboratory Yokohama Center (72) Inventor Yasuko Tsujino Midori-ku, Yokohama-shi, Kanagawa Umegaoka 6 2 Japan Tobacco Inc., Plant Development Laboratory Yokohama Center (72) Inventor Kenji Morita 6 Umegaoka 6, Midori Ward, Yokohama City, Kanagawa Japan Tobacco Inc. Plant Development Laboratory Yokohama Center

Claims (2)

[Claims] 1. A herbicide containing mineral oil as an active ingredient. 2. A herbicidal method, which comprises spraying the herbicide according to claim 1 directly onto a paddy field under flooding.