JPH1059812A - Insecticidal microcapsule agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a microcapsule agent of a pyrethroid-based insecticide, excellent in initial activities and residual effects for a long period and effective against a wide range of insect pests by mixing two kinds of microcapsules having different film thicknesses. SOLUTION: This insecticidal microcapsule agent composition comprises mixed two kinds of microcapsules, containing a pyrethroid-based insecticidal ingredient and respectively having 1-50μm average grain diameter and 0.001-0.01μm film thickness and 0.01-0.5μm film thickness. The film agent is prepared by polycondensing melamine-formaldehyde, methyolmelamine monomer or its low-molecular weight polymer. A formulation excellent in initial activities and residual effects for a long period can be obtained by mixing the microcapsule agents of the pyrethroid-based insecticide effective against a wide range of insect pests and the dose is reduced to save labors in spraying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyrethroid-based insecticide, which is excellent in initial activity and long-lasting effect by mixing two or more kinds of microcapsules having different film thicknesses and is effective against a wide range of pests. It relates to a capsule composition.

[0002]

2. Description of the Related Art Microcapsules, which are one of the preparations of agricultural chemicals, have been actively researched and developed as substitutes for emulsions and wettable powders because of their excellent effects on the environment and safety. . As for the microcapsules of pyrethroid insecticides, those using a polyurethane polymer as a material for the wall film of the microcapsules (JP-B-55-383)
No. 25, JP-A-2-196703), those using polyamide, polyamide / polyurea, polyurethane, or polyurea (JP-A-61-115006) and those using gelatin / gum arabic (Japanese Patent Laid-open No. No. 64-66104), and those using melamine / formaldehyde or derivatives thereof (JP-A-5-1787).
No. 03) is known.

By controlling the thickness and the particle size of the microcapsules, these microcapsules can maintain the insecticidal effect for a longer period of time as compared with the existing dosage forms, and can significantly reduce the toxicity to aquatic animals. There is a characteristic that.
Since pyrethroid insecticides are effective against many pests and mites, microcapsules of pyrethroid insecticides are effective for controlling such organisms.
Nevertheless, pyrethroid insecticides exhibit their activity when the drug comes into contact with pests and mites. This means that the properties of the capsule itself, such as the fragility of the membrane, are closely related to the expression of the insecticidal effect. For small insects such as mites, increasing the film thickness does not have any effect, while for large insects such as cockroaches, the effect is exhibited even if the film is thick. In addition, the occurrence of pests in nature is not simultaneous, and pesticides are required to have an initial activity that shows an effect immediately after being sprayed, and an effect (residual effect) on flying one after a few days or weeks. Therefore, it is difficult for a microcapsule of a pyrethroid insecticide having a single particle size and a single film thickness to simultaneously exhibit sufficient activity against various types of pests. That is, it is possible that a microcapsule having an optimized particle size and film thickness for a certain kind of pest does not exert a sufficient effect on other pests as it is.

As described above, the conventional microcapsules of pyrethroid insecticides having a single particle size and film thickness cannot sufficiently utilize the broad insecticidal spectrum of pyrethroid insecticides.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems and to provide excellent initial activity and long-lasting effect by mixing two or more kinds of microcapsules having different film thicknesses. An object of the present invention is to provide a microcapsule composition of a pyrethroid insecticide that is effective against a wide range of insects.

An object of the present invention is to provide a core material containing a pyrethroid-based insecticidal active ingredient coated with a wall film and having an average particle size of 1 to 5 particles.
An object of the present invention is to provide a microcapsule composition having excellent initial activity and long-term residual effect by mixing microcapsules having two or more film thicknesses of 0 μm.

[0007]

The inventors of the present invention have conducted intensive studies and found that the average particle diameter is 1 to 50 μm and the film thickness is 0.001 to 0.01 or 0.01 to 0.5 μm. It has been found that the above problems can be solved by mixing two types of microcapsules, and a microcapsule composition having initial activity and residual activity can be obtained.

That is, according to the present invention, a core material containing a pyrethroid-based insecticidal active ingredient is coated with a wall film and has an average particle size of 1 to 5 particles.
A microcapsule composition comprising a microcapsule having a thickness of 0 μm, which provides an insecticidal microcapsule composition characterized by mixing two or more types of microcapsules. It is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The microcapsules constituting the insecticidal microcapsule composition of the present invention are melamine-containing.
Formaldehyde, methylol melamine monomer or its low molecular weight polymer, alkylated methylol melamine monomer or its low molecular weight polymer and one or more selected from the group consisting of a combination thereof, an anionic polymer surfactant Is dissolved in water containing, and in the solution, a liquid pyrethroid-based insecticidally active ingredient or a pyrethroid-based insecticidally active ingredient serving as a core agent is dissolved or compatible with a high-boiling-point solvent, and the mixture is emulsified and dispersed, followed by heating. And around the emulsified particles,
It is produced by polycondensing the melamine monomer and / or the low molecular weight polymer to form a wall film.

[0010] As a core substance of the microcapsule constituting the insecticidal microcapsule composition of the present invention, it is essential to contain a pyrethroid-based insecticidal active ingredient. As such a pyrethroid insecticidal active ingredient,
2- (4-ethoxyphenyl) -2-methylpropyl
3-phenoxybenzyl ether [ethofenprox], 2- (4-difluorobromomethoxyphenyl)
-2-methylpropyl 3-phenoxybenzyl ether [halphenprox], 3-phenoxybenzyl (1RS) -cis / trans-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxylate [permethrin ], Α-cyano-3-phenoxybenzyl-1- (4-ethoxyphenyl) -2,2-dichlorocyclopropanecarboxylate [cycloprotoline], (RS) -α-cyano-3-phenoxybenzyl (RS) -2- (4-chlorophenyl) -3-isovalerate [fenvalerate], (S) -α-cyano-3-phenoxybenzyl (S) -2- (4-chlorophenyl) isovalerate [esfenvalerate], α
-Cyano-3-phenoxybenzyl (S) -2- (4
-Difluoromethoxyphenyl) isovalerate [flucitrinate], α-cyano-3-phenoxybenzyl
(S) -2- (2-chloro-4-trifluoromethylaniline) isovalerate [fluvalinate], (RS)
-Α-cyano-3-phenoxybenzyl 2,2,3
3-tetramethylcyclopropanecarboxylate [fenpropasulin], 3-phenoxybenzyl (1
R) -cis / trans-chrysanthemate [d-phenothrin], (RS) -α-cyano-3-phenoxybenzyl (1R) -cis / trans-chrysanthemate [cyphenothrin], (RS) -3-allyl- 2-methyl-4-oxocyclopent-2-enyl (1R
S) -cis / trans-chrysanthemate [aresulin], α-cyano-3-phenoxybenzyl (1R)
-Cis / trans-3- (2,2-dichlorovinyl)-
2,2-dimethylcyclopropanecarboxylate [cypermethrin], (S) -α-cyano-3-phenoxybenzyl (1R) -cis-3- (2,2-dimethylcyclopropanecarboxylate [deltamethrin],
(S) -α-3-phenoxybenzyl (1R) -cis-2,2-dimethyl-3- (1,2,2,2-tetrabromoethyl) cyclopropanecarboxylate [tralomethrin], 3,4,5 , 6-Tetrahydroimidomethyl (1RS) -cis / trans-chrysanthemate [tetramethrin], 5-benzyl-3-furylmethyl (1RS) -cis / trans-chrysanthemate [resmethrin], α-cyano-4- Fluoro-3-phenoxybenzyl (1R, trans) -2,2-dimethyl-3- (2,2-dichlorovinyl) cyclopropanecarboxylate [cyfluthulin] and the like. It is also possible to use a mixture of these active ingredients and a mixture with other insecticides, acaricides and the like.

It is desirable that a water-insoluble, high-boiling solvent be mixed with the core substance as a solvent in addition to the pyrethroid-based insecticidal active ingredient. Examples of high boiling point solvents include alkylbenzenes,
Phenylxylylethane, methylnaphthalene or
Alkyl esters such as phthalic acid, trimellitic acid, sebacic acid and adipic acid can be used. Particularly, in consideration of the stability of the effect, the effect on the environment, etc., alkyl phthalate esters having 8 to 13 carbon atoms in the alkyl group are particularly preferable, and the alkyl group shows either a straight chain or a branched chain. The mixing ratio of the cosolvent also depends on the concentration of the active ingredient in the intended microcapsule slurry, but it is desirable that the content is 10 to 90% in the hydrophobic solution as the core substance. As the phthalic acid alkyl ester having an alkyl group having 8 to 13 carbon atoms according to the present invention,
Examples thereof include dinormal octyl phthalate, dinormal nonyl phthalate, diisononyl phthalate, dinormal decyl phthalate, diisodecyl phthalate, dinormal undecyl phthalate, dinormal dodecyl phthalate, and dinormal tridecyl phthalate. These alkyl phthalates may be used alone or as a mixture of several kinds. If necessary, a synergist such as piperonyl butoxide may be incorporated in the core material.

The anionic high molecular surfactants used for emulsifying and dispersing the core substance, which is a hydrophobic solution, include copolymers of ethylene / maleic anhydride and styrene /
Maleic acid copolymers, vinyl acetate / maleic anhydride copolymers and the like can be used.
1-44 described (A) acrylic acid, methacrylic acid,
(B) acrylonitrile or methacrylonitrile, (C)
Anionic polymeric surfactants obtained by polymerizing at least one monomer from the respective monomers of acrylamide alkyl sulfonic acid or sulfoalkyl ester of acrylic acid are preferred. More preferably, (A) acrylic acid 20 to 70 mol%, (B) acrylonitrile 20 to 70
Mol%, (C) 2-acrylamido-2-methylpropanesulfonic acid is a copolymer having a monomer constitution of 0.5 to 20 mol% or a salt thereof, and a 20% by weight aqueous solution thereof has a pH of 2.0, 10 to 1000 cps at 25 ° C
Is preferred.

The starting material of the melamine-formaldehyde polycondensate which forms the microcapsule wall film in the present invention includes:
One or more water-soluble capsule walls selected from the group consisting of melamine-formaldehyde, methylol melamine monomer or low molecular weight polymer thereof, alkylated methylol melamine monomer or low molecular weight polymer thereof, and a combination thereof A precursor is used.

The microencapsulation is carried out by dissolving melamine-formaldehyde or a derivative thereof as a capsule wall precursor in an aqueous solution containing an anionic polymer surfactant, and injecting the insecticidal active ingredient as a core substance into the solution. Is emulsified and dispersed by using an emulsifying and dispersing apparatus, and then heated to cause a polymerization reaction. The preferred method is as follows. That is, a solution prepared by adjusting the pH of an aqueous solution containing a certain amount of an anionic polymer surfactant shown in the above-mentioned JP-A-61-4524 to about 4 with 5N NaOH, and containing a water-soluble capsule wall precursor, namely melamine- Dissolve the formaldehyde derivative,
T. K. Automixer (Toki Kika Kogyo Co., Ltd.)
The emulsifying and dispersing device as described above emulsifies and disperses a hydrophobic solution containing an insecticidal active ingredient as a core substance. The emulsifying apparatus may vary depending on the target particle size, but a homomixer, a homogenizer, a homodisper, or the like can be used, and the number of revolutions, time, and the like can be changed to reduce the particle size to the target particle size. Thereafter, the emulsified dispersion is heated to about 60 ° C. at an acidic side, preferably around pH 4, and
The desired microcapsule slurry can be obtained by reacting for about 3 hours. After the encapsulation reaction, the obtained capsule dispersion liquid is diluted with water so as to have a predetermined bulk concentration, and if necessary, a suspension stabilizer is added to obtain a stable slurry-type preparation.

If it is necessary for hygiene to remove and reduce remaining free formaldehyde after formation of the microcapsule wall film, urea, ethylene urea, sulfite, saccharide, ammonia, amine, formamide, Addition of hydroxyamine salt (hydrochloride, sulfate, phosphate), melamine, compound having active methylene group, hydroxyalkylamine, acrylamide, acrylamide copolymer, etc. and formaldehyde harmless substance under appropriate reaction conditions , It is possible to remove the remaining formaldehyde.

As the suspension stabilizer of the capsule slurry,
Natural polysaccharides such as xanthan gum and locust bean gum;
Semi-synthetic polysaccharides such as carboxymethylcellulose and hydroxypropylcellulose; synthetic polymers such as sodium polyacrylate; magnesium aluminum silicate; mineral powder such as high-purity bentonite; used alone or as a mixture of two or more. Is done. These thicken and stabilize the capsule slurry. Furthermore, suspension stability,
Lignin sulfonate to improve dispersion stability,
Formalin condensate of sodium naphthalene sulfonate,
Anionic surfactants such as polyoxyethylene alkyl allyl sulfate salt, polyoxyethylene styryl phenyl ether sulfate salt, polyoxyethylene nonyl ether sulfate salt, polyoxyethylene nonyl phenyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene alkyl A nonionic surfactant such as allyl ether can be used alone or in combination.

The diameter (particle size) of the microcapsule particles is
It is difficult to prepare a uniform one, has a certain distribution width, and is represented by an average particle size. The average particle size of the prepared microcapsules is determined by the type and concentration of the dispersing agent used in the suspension and dispersion, and the strength of mechanical stirring during suspension and dispersion. Taking into account the ease of agglomeration), the ease of spraying, the ease of mechanical particle control, and the like, it is usually desirable to adjust the thickness to a range of 1 to 50 μm.

The weight ratio of melamine-formaldehyde or a derivative thereof to the core substance used in the present invention is preferably from 1: 500 to 1:20. The thickness (film thickness) of the wall film of the microcapsule varies depending on the volume ratio of the core substance and the water-soluble capsule wall precursor, and it is difficult to directly measure it, but it can be obtained by an approximate expression. That is, the average particle diameter of the microcapsules is d, the weight of the core substance is Wc, the weight of the membrane substance is Ww, the density of the core substance is ρc, and the density of the membrane substance is ρ.
Assuming w, it is calculated by the following equation.

[0019]

(Equation 1) The film thickness of the microcapsules in the present invention is 0.01
It is appropriately selected in a range of 0.5 μm. In order to obtain a composition of the present invention comprising two types of microcapsules,
For example, a microcapsule having a thickness of 0.001 to 0.01 μm and a microcapsule having a thickness of 0.01 to 0.5 μm may be separately adjusted.

The film thickness of the microcapsule according to the present invention is determined by the amount and particle size of the film substance when the core substance is fixed. However, the particle size is 1 to 5 as described above.
The range of 0 μm is appropriate, and therefore, the control of the film thickness is achieved by changing the amount of the film agent added. but,
Since the particle size is as described above, it is difficult to widen the film thickness. Therefore, it is impossible to obtain a microcapsule having an initial activity and a residual effect by a single microcapsule preparation operation by utilizing the broad spectrum of the pyrethroid-based insecticidal active ingredient.

The composition of the present invention may be used by mixing two or more kinds of the microencapsulating agents obtained as described above and mixing them. Depending on the type of pests and mites,
Arbitrarily determined.

When the composition of the present invention is used for controlling pests in paddy fields, vegetable gardens, orchards, etc., these can be diluted with water so as to have a predetermined concentration and then sprayed.

[0023]

EXAMPLES In order to clarify the content of the present invention, the present invention will be specifically described below with reference to formulation examples and test examples, but the present invention is not limited to these examples.

Example 1 Anionic polymeric surfactant (acrylic acid, acrylonitrile, acrylamide propane sulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) is added to this solution, and 154. A mixture of the same amount of etofenprox base material and Vinicizer 100 (phthalate ester-based solvent; Kao) is added as a core substance. 2 g. K. The mixture was emulsified and dispersed at a rotation speed of 6000 rpm for 5 minutes using an auto-homomixer (mixing machine; Tokushu Kika Kogyo Co., Ltd.), and pulverized to an average particle size of 10 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, an aqueous solution of Kelzan S (xanthan gum; tricrystal) was added to a final concentration of 0.2% to obtain a microcapsule I (film thickness 0.21 μm). The amount of Euramine T-34 was reduced to 0.
67g of microcapsule II (average particle size 10μ)
m, film thickness O. OO5 μm). Microcapsules I and II were mixed in equal amounts to obtain a microcapsule composition containing 20% of etofenprox.

Example 2 Anionic polymeric surfactant (acrylic acid, acrylonitrile, acrylamide propane sulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) is added to this solution, and Etofenprox and Hisol S are used as core materials.
154.2 g of the same mixture of AS296 (phenylxylylethane solvent; Nippon Petrochemical) was added. K. 4 using an auto homomixer (mixer;
The mixture was emulsified and dispersed at a rotation speed of 000 rpm for 5 minutes, and pulverized to an average particle size of 20 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, an aqueous solution of Kelzan S (xanthan gum; tricrystal) was added to a final concentration of 0.2%, and the microcapsule I (film thickness OO) was added.
42 μm). Euramine T-34 by similar operation
Was added to obtain 0.67 g of microcapsule II (average particle diameter: 20 μm, film thickness: 0.01 μm). Equal amounts of the microcapsules I and II were mixed to obtain a microcapsule composition containing 20% of the intended etofenprox.

Example 3 Anionic polymeric surfactant (acrylic acid, acrylonitrile, acrylamide propanesulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) is added to this solution, and the same amount mixture of an etofenprox raw material and Vinicizer 124 (phenylxylylethane-based solvent; Nippon Petrochemical) is added as a core substance. Was added, and the mixture was emulsified and dispersed for 5 minutes at a rotation speed of 4000 rpm using a homodisper (mixing machine; Tokushu Kika Kogyo Co., Ltd.) to form fine particles having an average particle size of 30 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, an aqueous solution of Kelzan S (xanthan gum; tricrystal) was added to a final concentration of 0.2% to obtain Microcapsule I (film thickness 0.063 μm). The amount of Euramine T-34 was reduced to 0.
19g of microcapsule II (average particle size 30μ)
m, thickness 0.004 μm). Equal amounts of the microcapsules I and II were mixed to obtain a microcapsule composition containing 20% of the intended etofenprox.

Example 4 Anionic polymer surfactant (acrylic acid, acrylonitrile, acrylamide propanesulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) is added to this solution, and 154.2 is a mixture of the same amount of the Harfenprox raw material and Vinicizer 100 (phthalate-based solvent; Kao).
g. K. The mixture was emulsified and dispersed for 5 minutes at a rotation speed of 6000 rpm using an auto-homomixer (mixing machine; Tokushu Kika Kogyo Co., Ltd.), and pulverized to an average particle size of 20 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, Kelzan S is used so that the final concentration becomes 0.2%.
An aqueous solution of (xanthan gum; tricrystal) was added to obtain Microcapsule I (film thickness 0.41 μm). In the same manner, the amount of Euramine T-34 added was changed to O. 48 g of microcapsule II (average particle diameter 20 μm, film thickness 0.007 μm)
m). Equal amounts of microcapsules I and II are mixed,
A microcapsule composition containing 20% of etofenprox was obtained.

Example 5 Anionic polymeric surfactant (acrylic acid, acrylonitrile, acrylamide propanesulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) was added to this solution, and Hafenprox and Hisol S were used as core materials.
154.2 g of the same mixture of AS296 (phenylxylylethane solvent; Nippon Petrochemical) was added. K. 7 using an auto homomixer (mixer;
The mixture was emulsified and dispersed at a rotation speed of 000 rpm for 5 minutes, and pulverized to an average particle size of 10 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, an aqueous solution of Kelzan S (xanthan gum; tricrystal) was added so that the final concentration was 0.2%, and the microcapsule I (thickness: 0.0
21 μm). Euramine T-34 by similar operation
Was added to obtain 0.77 g of microcapsule II (average particle size: 10 μm, film thickness: 0.005 μm). Equal amounts of the microcapsules I and II were mixed to obtain a microcapsule composition containing 20% of the intended etofenprox.

Example 6 Anionic polymer surfactant (acrylic acid, acrylonitrile, acrylamide propane sulfonic acid copolymer; Mitsui Toatsu Chemicals) 38.5 in 104.3 g of ion-exchanged water 38.5
Dissolve 6 g and adjust the pH to 4 with 5N caustic soda. 2.90 g of Euramine T-34 (methylolated melamine; Euramine Kogyo) is added to this solution, and a mixture of equal amounts of a Harfenprox raw material and Vinicizer 124 (phenylxylylethane-based solvent; Nippon Petrochemical) is used as a core substance. Was added and the mixture was emulsified and dispersed at 8000 rpm for 5 minutes using a homomixer (mixer; Tokushu Kika Kogyo Co., Ltd.), and pulverized to an average particle size of 5 μm. Next, the mixture was gently stirred in a thermostat at 60 ° C. to obtain a melamine membrane capsule dispersion in which methylolated melamine was polycondensed. Further, an aqueous solution of Kelzan S (xanthan gum; tricrystal) was added to a final concentration of 0.2% to obtain a microcapsule I (film thickness: 0.01 μm). The amount of Euramine T-34 was reduced to 0.
29 g of microcapsule II (average particle size 5 μm,
A film thickness of 0.001 μm) was obtained. Microcapsule I and
Mix equal amounts of II and add the desired etofenprox to 2
A microcapsule composition containing 0% was obtained.

Test Example 1 Insecticidal test against brown planthoppers Five rice plants are transplanted as one bundle into a resin pot of 1 / 10,000a, and grown in a greenhouse until the leaf age becomes 4 to 5 leaves. The microcapsule composition and the comparative agent obtained in the examples were each diluted with water so that the active ingredient concentration became 100 ppm, and sprayed on rice. This was covered with a wire net, and ten brown planthoppers were released therein every predetermined number of days, and survival or death was determined 24 hours later. The test was performed in three repetitions. The results are shown in Table 1 (Table 1).

[0031]

[Table 1] MCI: Microcapsule I MCII: Microcapsule II Composition: Microcapsule composition

Test Example 2 Test for controlling effect on citrus red mite The microcapsule composition obtained in the example was diluted with water so that the active ingredient concentration became 25 ppm, respectively, sprayed on a potted tangerine, and kept in a greenhouse. . Leaves are collected every predetermined number of days, cut out into 2 cm squares and placed on a Petri dish,
Ten citrus red mites were released on top of them, and survival and death were determined 48 hours later. The results are shown in Table 2 (Table 2).

[0033]

[Table 2] MCI: Microcapsule I MCII: Microcapsule II Composition: Microcapsule composition

[0034]

EFFECT OF THE INVENTION By mixing two kinds of microcapsules having different thicknesses of the pyrethroid insecticide microcapsules which are effective against a wide range of pests, a preparation having excellent initial activity and long-term residual effect can be obtained. It can be provided, and the amount of medicine can be reduced and the labor for spraying can be reduced.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Morinaga 1144 Togo Mitsui Toatsu Chemical, Mobara City, Chiba Prefecture (72) Inventor Takeshi Takeshi Imakita 1144 Togo Togo, Mobara City, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Eiichi Yamada 1144 Togo, Mobara-shi, Chiba Mitsui Toatsu Chemicals Co., Ltd.

Claims (4)

[Claims] 1. A microcapsule composition comprising a microcapsule having a core material containing a pyrethroid-based insecticidal active ingredient covered with a wall film and having an average particle size of 1 to 50 μm, wherein at least two types of microcapsules are used. An insecticidal microcapsule composition characterized by mixing a microcapsule having a thickness. 2. A microcapsule having a core material containing a pyrethroid-based insecticidal active ingredient coated with a wall film having a thickness of 0.001 to 0.01 μm and having an average particle size of 1 to 50 μm, and said core material. And a microcapsule having an average particle size of 1 to 50 μm coated with a wall film having a thickness of 0.01 to 0.5 μm. 3. The insecticidal microcapsule composition according to claim 2, wherein the wall film comprises a thin film obtained by polycondensation of melamine-formaldehyde, a methylolated melamine monomer or a low molecular weight polymer thereof. . 4. The pyrethroid insecticidal active ingredient is 2-
(4-ethoxyphenyl) -2-methylpropyl 3-
The insecticidal microcapsule composition according to claim 2, which is phenoxybenzyl ether (ethofenprox) or 2- (4-difluorobromomethoxyphenyl) -2-methylpropyl 3-phenoxybenzylether (halfenprox).