JPH09169604A - Herbicides and methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a herbicide which can develop the herbicidal effect without any adverse effect on its soil fumigation effect by applying chloropicrin prepared in a specific form to the surface of the soil in which seeds of weeds are mixed. SOLUTION: This herbicide contains chloropicrin as an active ingredient and is prepared by using an oil-absorbing carrier (particularly starch or its hydrolyzate is preferred) or a gelling agent or by packing the chemical with a water-soluble film. Such prepared chloropicrin is preferably formed in a tape. This herbicide is preferably applied by placing it on the surface of the soil or further by covering the soil surface after application of this chloropicrin tape with a covering material. Weeds such as grass weeds, for example, pangola grass (Digitaria adscendens), cyperaceous weeds, for example, rice flatsedge (Cyperus iria) and broad leaf weeds such as redroot pigweed (Amaranthus retroflexus) or cocklebur, Xanthium strumarium can be controlled. This herbicide can very simply and readily develop its sufficient effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a herbicide for weeds and a method for weeding containing chloropicrin as an active ingredient.

[0002]

2. Description of the Related Art Conventionally, in cultivating crops, weeding work has been positioned as an important work, and various methods are used depending on the purpose such as using a herbicide or manual handling. As one of the methods, soil fumigation with methyl bromide is used not only for controlling soil pests but also for controlling annual weeds. But,
In the herbicidal method using methyl bromide, the vapor pressure of methyl bromide itself is high and it is a gas at room temperature, so it easily volatilizes into the air, and if the hermetically sealed parts do not have a herbicidal effect, this phenomenon is often seen. Is. Methyl bromide is a substance that has been certified as an ozone depleting substance, its use is restricted, and even in the near future, it will be prohibited to use it as a soil fumigant.

On the other hand, chloropicrin is also a soil fumigant which has been widely used since ancient times, and it is known that it is slightly effective against weeds as well as soil pests. However, the herbicidal effect was not sufficient, and it was not possible to simultaneously control pests and weeds by soil fumigation like methyl bromide.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a herbicidal method using chloropicrin and a herbicide for weeds containing chloropicrin as an active ingredient.

[0005]

[Means for Solving the Problems] As a result of intensive studies to solve the above-mentioned problems, the present inventors have surprisingly applied chloropicrin formulated to the surface of soil mixed with seeds of weeds, It was found that the herbicidal effect can be expressed without reducing the soil fumigation effect, and the present invention was completed.

That is, the present invention is (1) a herbicide containing chloropicrin as a medicinal component, and (2) chloropicrin contains a carrier capable of absorbing oil or a gelling agent (1). (3) The formulated herbicide described in (2), wherein the oil-absorptive carrier is starch or a decomposed product thereof. 4) The herbicide according to any one of (1) to (3), characterized in that chloropicrin is packaged in a water-soluble film.
Further, (5) the formulated chlorpicrin is in the form of a tape, which is the herbicide according to any of (2) to (4), and (6) the chlorpicrin is allowed to stand on the soil surface. A herbicidal method characterized by applying the chlorpicrin prepared by the method described in any one of (7), (2) to (5), and applying the chloropicrin on the soil surface. It is a method of weeding, and (8) is characterized by covering the soil surface after application with a coating material (6)
Or (7) the weeding method described above, and (9) the weeds to be weeded are grass family weeds, Cyperaceae family weeds or broadleaf weeds, wherein any one of (1) to (5) It is a herbicide, and (10) characterized in that grass weeds are selected from crabgrass and Enocorogusa, cyperaceae weeds are Kogomegayatsu, and broad-leaved weeds are selected from Aoyu, Onamomi, Shiroza, Scutellaria and Abutilon. (9) The herbicide according to (9), and (11)
The weeds to be weeded are grass weeds, Cyperaceae weeds or broad-leaved weeds, which is the weeding method according to any one of (6) to (8), and (12) the grass weeds are honeyweed, The herbicidal method according to (11), which is selected from Enocorogusa, the Cyperaceae weed is Kogomegayatsuya, and the broad-leaved weed is selected from Aoyuyu, Onami fir, Shiroza, Inutadashi, and hibiscus.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The chloropicrin formulated according to the present invention can be used without limitation as long as liquid chloropicrin is not substantially fluidized, and many proposals have already been made. -192301, JP-A-59-82303, JP-A-63-23
No. 0602, JP 01-172302 A, JP 6-345605 A and the like. Specifically, for example, chloropicrin is mixed with a gelling agent to form a gel, powdered or granular solid carrier is solidified and supported, oil-absorbent polymer is absorbed, and these are packaged in a single package. An example thereof is that each unit is packaged with a water-soluble film, and most simply, liquid chloropicrin is enclosed in a bag-like or container-like water-soluble film in a liquid state. Among them, those obtained by mixing ultrafine particle silica and chloropicrin to form a gel, or absorbing oil of chloropicrin into an oil-absorptive carrier such as starch or a decomposition product thereof, or covering them with a water-soluble film to prepare a formulation. Is environmentally friendly and has excellent formulation safety. Furthermore, among them, chloropicrin is difficult to be adsorbed to soil particles, and has a high oil absorption capacity, and when applied to the soil, the active ingredient of the preparation is rapidly released to the soil, and after application, the carrier dissolves in water and is decomposed by microorganisms in the soil. Partial degradation products of starch, which have the property of being easily broken, are particularly excellent. As the water-soluble film, polyvinyl alcohol or water-soluble paper is preferably used.

There is no limitation on the chloropicrin content in the formulated chloropicrin of the present invention, and those having a chloropicrin content of 5 to 99% by weight are preferably used.
In addition, there is no problem even if other pesticide components are mixed in the formulated chlorpicrin.

The shape of chloropicrin formulated in the present invention is not limited, but those packaged with a water-soluble film are exemplified by rectangles, cylinders, spheres, and the like, and a plurality of these packaging units are linear. Alternatively, a tape-shaped product connected in a plane is preferably used because the application work can be simplified.

In the present invention, the application amount of chloropicrin is 5 to 10 ars of farmland as chloropicrin active ingredient.
80 kg is preferred. If it is less than 5 kg, the herbicidal effect is not sufficiently obtained, and if it is applied more than 80 kg, it is economically disadvantageous.

The soil to which the present invention is applied can be applied without limitation as long as it is a soil which is mixed with seeds of highly damaging weeds in an open field or a field in a greenhouse. The seeds of the weeds referred to herein are sedgegrass, grass weeds selected from Enocorogusa, etc., Cyperaceae weeds selected from Kogomegayatsu, etc., Aobiyu, Onami fir, white leaves, broad-leaved weeds selected from Acanthaceae, etc., 1 or 2 seeds such as
See more than seeds. The chlorpicrin or the formulated chloropicrin according to the present invention does not work effectively for controlling all weeds, and it is not as effective as the above-mentioned weeds for tuber-like weeds such as, for example, nutsedges. . The soil to which the present invention is applied is preferably tilled and crushed before application so that the herbicidal effect can be further exhibited.

In the application method of the present invention, it is only necessary to leave the formulated chlorpicrin on the surface of the soil to which it is applied, and it is not always necessary to mix it with the soil of the surface layer after application, and the soil may be slightly covered after application. However, it is not always necessary. Further, it is preferable to carry out so-called mulching in which the soil surface after application is covered with a coating material such as vinyl chloride or polyethylene because the effect is further enhanced. Further, it was found that even when unformulated chlorpicrin was used, it had a controlling effect on highly damaging weeds such as crabgrass, locust, kogomegayatsu, aobiyu, konomimi, white azalea, sardine, and hibiscus.

That is, the one in which chloropicrin was simply absorbed by starch, or the one in which the chlorpicrin undiluted solution was put in an unsealed glass container was allowed to stand still on the surface of the soil seeded with the above-mentioned severely weeded seeds. Even when the soil surface was coated with a coating material such as agricultural vinyl chloride or polyethylene, the above-mentioned highly damaging weeds did not germinate at all. However, only by irrigating the chlorpicrin stock solution into the soil, the liquid active ingredient was diffused into the soil, and a considerable amount was adsorbed to the soil, so that the original effect of controlling weeds was not recognized. When the application method of the present invention is performed, it is preferable to apply chloropicrin formulated to the soil surface at regular intervals, since there is no problem and chloropicrin can be applied uniformly.

[0014]

The present invention will be described more specifically with reference to the following examples. Chlorpicrin stock solution (manufactured by Mitsui Toatsu Chemicals, purity: 99.5%) (3.0 g) was placed in a 5 × 5 cm square bag made of polyvinyl alcohol film KA40 (manufactured by Aicello Co., Ltd.), and heat-sealed to form a chlorpicrin agent package. Obtained. This was designated as formulation A.

Chlorpicrin stock solution (Mitsui Toatsu Chemical Co., Ltd .:
0.5 g of a 20% dimethylformamide solution of dibenzylidene sorbitol was added to 3.0 g of pure 99.5%) and gelled.
Put it in a 5 x 5 cm square bag made by
Heat sealing was performed to obtain a chlorpicrin agent package. This was designated as formulation B.

Chlorpicrin stock solution (Mitsui Toatsu Chemical Co., Ltd .:
(99.5% purity) 3.0 g of ultrafine silica anhydrous silica: Aerosil (manufactured by Nippon Aerosil Co., Ltd.) was added and kneaded into a 5 × 5 cm square bag made of polyvinyl alcohol film KA40 (manufactured by Aicello Co., Ltd.). It was put in and heat-sealed to obtain a chloropicrin agent package. This was designated as formulation C.

Chlorpicrin stock solution (Mitsui Toatsu Chemical Co., Ltd .:
Purity 99.5%) 3.0 g Corn starch 3.0 g
Was added and kneaded, and the mixture was placed in a 2 × 12 cm square bag made of polyvinyl alcohol film HYCELON C (manufactured by Nigo Film Co., Ltd.) and heat-sealed to obtain a chloropicrin agent package. This was designated as formulation D. 12 preparations D were connected in the longitudinal direction to obtain a tape-shaped preparation having a total length of about 500 cm. In addition,
Formulation D and Formulation D were connected by a PVA film containing nothing. This was designated as formulation E.

Chlorpicrin stock solution (Mitsui Toatsu Chemicals:
Purity 99.5%) 3.0 g Corn starch 3.0 g
And kneaded. This was designated as formulation F. Dextrin (Matsuya Chemical Co., Ltd .: Max 1000) was added to 3.0 g of chloropicrin stock solution (Mitsui Toatsu Chemical Co., Inc .: Purity 99.5%).
Add 5 g and knead, polyvinyl alcohol film KA
40 (manufactured by Aicello) was placed in a 4 × 15 cm square bag and heat-sealed to obtain a chloropicrin agent package. This was designated as Preparation G.

The total length of the preparation G is about 5 by connecting 12 preparations G in the longitudinal direction.
A 00 cm tape preparation was obtained. Formulation G and formulation G
Between them are connected by a PVA film that does not contain anything. This was designated as Formulation H.

[Test Example 1] In the field, a tractor was used to cultivate and cultivate soil at a depth of 20 cm, and the width was 120 cm and the length was 600 cm.
cm was used as the test section. The preparation A was left on the soil surface over a length of 500 cm at the center of the test area at intervals of 30 cm. Seeds of crabgrass and pearl millet were sown on the soil surface. After the treatment, the soil surface was covered with a polyethylene film having a thickness of 0.02 mm. After 14 days from the treatment, the polyethylene film coating was removed, and 21 days after the treatment, the germination degree of the crabgrass and pearl millet was observed every 10 cm in the horizontal direction from the application part (Table 1). As a result, it was found that a sufficient herbicidal effect was exhibited.

[Test Example 2] The results of Table 1 were obtained in the same manner as in Test Example 1 except that Formulation A was used as Formulation B. [Test Example 3] The results of Table 1 were obtained in the same manner as in Test Example 1 except that Formulation A was used as Formulation C. [Test Example 4] The results of Table 1 were obtained in the same manner as in Test Example 1 except that Formulation A was used as Formulation D.

[Test Example 5] The preparation E was allowed to stand on the soil surface of the same test section as in Test Example 1 while extending the length to 500 cm in the central part of the test section. Seeds of crabgrass and pearl millet were sown on the soil surface. After treatment, the soil surface has a thickness of 0.02 mm
Of polyethylene film. 14 days after the treatment, the polyethylene film coating was removed and the same evaluation as in Test Example 1 was carried out to obtain the results shown in Table 1.

[Test Example 6] The results of Table 1 were obtained in the same manner as in Test Example 1 except that Formulation A was used as Formulation F. [Comparative Example 1] The liquid chloropicrin used in Test Example 1 was irrigated with an irrigation machine at 15 cm below the soil surface at intervals of 30 cm, 5 ml per well, over a length of 500 cm in the center of the test area. Seeds of crabgrass and pearl millet were sown on the soil surface. After the treatment, the soil surface was covered with a polyethylene film having a thickness of 0.02 mm. The polyethylene film coating was removed 14 days after the treatment, and the same evaluation as in Test Example 1 was performed (Table 1). No sufficient herbicidal effect was obtained.

[Comparative Example 2] The liquid chloropicrin used in Test Example 1 was applied to the soil surface at intervals of 30 cm at 5 points per location.
The solution was added dropwise by 500 ml over the length of 500 cm in the center of the test area, and the soil surface was quickly covered with a polyethylene film having a thickness of 0.02 mm after the treatment. The work of application was extremely difficult due to the lacrimatory and irritating properties of chlorpicrin. Seeds of crabgrass and pearl millet were sown on the soil surface. The polyethylene film coating was removed 14 days after the treatment, and the same evaluation as in Test Example 1 was performed (Table 1). No sufficient herbicidal effect was obtained.

[Comparative Example 3] The preparation A used in Test Example 1 was applied 15 cm below the surface of the soil at intervals of 30 cm, one per hole over a length of 500 cm in the central portion of the test area to cover the soil. Seeds of crabgrass and pearl millet were sown on the soil surface. After the treatment, the soil surface was covered with a polyethylene film having a thickness of 0.02 mm. The polyethylene film coating was removed 14 days after the treatment, and the same evaluation as in Test Example 1 was performed (Table 1). No sufficient herbicidal effect was obtained.

[0026]

[Table 1] [Test Example 7] 20 cm depth in the field with a tractor
The soil was cultivated and cultivated, and a width of 120 cm and a length of 600 cm were used as test sections. Formulation H on soil surface, length 500c in the center of test area
It was left still while being extended to m. The soil surface was sown with seeds of Enocorogosa, Prunus fruticosa, Shiroza, Spodoptera litura, and Abutilon. After the treatment, the soil surface was covered with a polyethylene film having a thickness of 0.02 mm. After 14 days from the treatment, the polyethylene film coating was removed, and 21 days after the treatment, the germination degree of Enocologsa, Prunus chinensis, Shiroza, Scutellaria edulis, and Abutilon was observed every 10 cm in the horizontal direction from the application part (Table 2).
As a result, it was found that a sufficient herbicidal effect was exhibited.

[Comparative Example 4] The liquid chloropicrin used in Test Example 7 was irrigated with an irrigation machine at 15 cm below the soil surface at intervals of 30 cm, 5 ml per hole, and the length of the central part of the test section was 50.
Irrigation over 0 cm. The soil surface was sown with seeds of Enocorogosa, Prunus fruticosa, Shiroza, Spodoptera litura, and Abutilon. After the treatment, the soil surface was covered with a polyethylene film having a thickness of 0.02 mm. The polyethylene film coating was removed 14 days after the treatment, and the same evaluation as in Test Example 7 was performed (Table 2). No sufficient herbicidal effect was obtained.

[0028]

[Table 2]

[0029]

EFFECTS OF THE INVENTION As can be seen from the above test examples, conventional chlorpicrin and chlorpicrin application methods do not provide sufficient herbicidal effects, and the application methods also involve great difficulty due to the lacrimatory and irritating properties of chlorpicrin. It was found that according to the method of the present invention, a sufficient herbicidal effect can be obtained very easily.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanemitsu Miyama 1144 Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Yu Arai 1144, Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chem. 72) Inventor Hitoshi Shimotori 1144, Togo, Mobara-shi, Chiba Mitsui Toatsu Chemical Co., Ltd.

Claims (12)

[Claims] 1. A herbicide containing chloropicrin as a medicinal component. 2. The formulated herbicide according to claim 1, wherein chlorpicrin contains a carrier capable of absorbing oil or a gelling agent. 3. The formulated herbicide according to claim 2, wherein the oil-absorbent carrier is starch or a decomposed product thereof. 4. The herbicide according to any one of claims 1 to 3, wherein chloropicrin is packaged in a water-soluble film. 5. The herbicide according to any one of claims 2 to 4, wherein the formulated chloropicrin is in the form of a tape. 6. A method of weeding, characterized in that chloropicrin is left standing and applied on the soil surface. 7. A herbicidal method comprising applying the formulated chloropicrin according to any one of claims 2 to 5 by allowing it to stand on a soil surface and applying it. 8. The herbicidal method according to claim 6, wherein the soil surface after application is covered with a covering material. 9. The weeds to be weeded are grass weeds, Cyperaceae weeds or broad-leaved weeds.
The herbicide according to any one of 5 to 5. 10. The grass family weeds are selected from Cercis chinensis and Enocorogusa, the cyperaceae family is Kogomegayatsu, and the broad-leaved weeds are selected from Aoyuyu, Onamomi, Shiroza, Inutadashi and Ichibi. Herbicide. 11. The weeding method according to claim 6, wherein the weeds to be weeded are grass weeds, Cyperaceae weeds or broadleaf weeds. 12. The grass family weeds are selected from Cercis chinensis and Enocologsa, the Cyperaceae weeds are Kogomegayatsu, and the broad-leaved weeds are selected from Aoyu, Onamomi, Shiroza, Spodoptera chinensis, and Ichibi.
The weeding method described.