JPH0818936B2 - Organophosphorus insecticidal composition for controlling forest pests - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a dimethyl (thio) phosphoric acid type organophosphorus insecticide having an average particle size of 80 μm or less and a film thickness of 0.2 μm or more, The present invention also relates to a microencapsulated insecticidal composition for controlling forest pests, which is included in a polymer film having (average particle size / film thickness) of 200 or less.

<Prior Art> Forests are very important natural resources as industrial resources such as paper and pulp, and as building materials for houses. At the same time, forests function as an important oxygen source on the earth, and also play an important role in nature as a habitat for many other environmental organisms.

However, such important forest resources may be destroyed by various factors in the natural world. For example, there are natural disaster factors such as forest fires, typhoons, and landslides, as well as destruction of forests by pests.

In recent years, artificial forestation has been actively carried out in order to secure forest resources, and as a result, a forest composed of a single tree species can suffer decisive damage once a pest emerges. There is.

To control these pests, pesticides are generally emulsions, oils,
It is formulated into a dosage form such as a wettable powder or a flowable agent, which is mainly sprayed by air in the air.

However, the Journal of Japan Forest Society 62 (7) 249 (198
0), 62 (9) 350 (1980), etc., some hinoki cypress plants show an abnormal leaf-falling phenomenon due to dimethyl (thio) phosphoric acid type organophosphorus insecticides. Has been observed. However, there is no report on a dimethyl (thio) phosphoric acid type organophosphorus insecticide which does not cause such a leaf-falling phenomenon.

<Problems to be solved by the invention> In controlling forest pests, unlike general agricultural pest control, there is not a single plant layer, and sometimes mixed trees other than the intended tree are mixed. In addition, it is difficult to apply the drug only to the target forest by the aerial spraying method, and the drug may reach the non-target forest or the vicinity of the forest due to the influence of drift etc. There is.
For example, in the case of pine forests in Japan, it is often the case that mixed forests with cypress trees exist or cypress trees are planted around the pine forests. As described above, it has been observed that the dimethyl (thio) phosphoric acid type organophosphorus insecticide causes an abnormal defoliation phenomenon in certain cypresses. However,
According to the report, the frequency of individuals in which leaf litter appears appears to be considered to be extremely low, but there is no difference between an apparently normal cypress and a sensitive cypress, so It is impossible to predict this kind of drug damage. Therefore, when applying dimethyl (thio) phosphoric acid type organophosphorus insecticides to this field, it is practically applicable not only to cypress forests, but also to mixed pine / hinoki forests and pine forests in contact with cypresses as described above. There was a limit.

On the other hand, it is generally known that if an insecticide is microencapsulated, the active ingredient is encapsulated as a core substance of the microcapsule and can be prevented from being harmful to crops because it is isolated from the outside of the membrane. Microencapsulation cannot prevent phytotoxicity in all cases,
The effect is not always satisfactory.

<Means for Solving Problems> The inventors of the present invention have made various studies in view of such circumstances, and as a result, various factors constituting the microcapsule formulation, particularly particle size and film thickness, cause phytotoxicity of this kind on cypress. It was found that there is an important relationship with the present invention, leading to the present invention.

That is, according to the present invention, the average particle size is 80 μm or less and the film thickness is
0.2 μm or more, and (average particle size / film thickness) is 2
A microencapsulated insecticidal composition for controlling forest pests (hereinafter, referred to as the composition of the present invention), which comprises a dimethyl (thio) phosphoric acid type organophosphorus insecticide contained in a polymer coating of 00 or less. provide.

Examples of forest pests to which the composition of the present invention can be applied include, in Japan, other pine wood chafers that mediate pine tree nematodes that parasitize pine trees in Japan, as well as cedar beetles, harakobaku beetles, adults such as bark beetles, and the like.
There are larvae such as symphyllum, bee, pine beetle, gypsy moth, stag beetle, edulid duckweed, and scabbard worms.Overseas, in addition to larvae of spruce bud worms that infest new leaves of peach, Hemlock looper (Hemlock looper). ) Larva and the like.

As the dimethyl (thio) phosphoric acid type organophosphorus insecticide, a sparingly water-soluble one is suitable, and for example, O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate [fenitrothion (fenitrothion) ], S
-[1,2-bis (ethoxycarbonyl) ethyl] O, O-dimethyl phosphorodithioate [malathione
n)], O, O-dimethyl O- (3-methyl-4-methylthiophenyl) phosphorothioate [phenthion (fe
nthion)], O- (1,2-dibromo-2,2-dichloroethyl) O, O-dimethyl phosphate [naled,
S- (α-ethoxycarbonylbenzyl) O, O-dimethyl phosphorodithioate [phenthoa
te)], O- (4-cyanophenyl) O, O-dimethyl
Phosphorothioate [cyanophos], S
-[2- (ethylthio) ethyl] O, O-dimethyl phosphorodithioate [thiometon], S-
(2,3-dihydro-5-methoxy-2-oxo-1,3,4-
Thiadiazol-3-yl) methyl O, O-dimethyl
Phosphorodithioate (methidathione
n)], O, O-dimethyl O- (4-nitrophenyl) phosphorothioate [parathionmetny
l)], O- (2-diethylamino-6-methyl-4-
Pyrimidinyl) O, O-dimethyl phosphorothioate [pirimiphosmethyl], and the like.

Next, the method of microencapsulation will be described in detail.

The oil-soluble Reactor A is added to the oil phase containing the dimethyl (thio) phosphoric acid type organophosphorus insecticide, dispersed in the aqueous phase as droplets, and then the Actant B which reacts with the Reactant A to form a polymer. It is convenient and convenient to use an interfacial polymerization method in which is added to the water phase to cause film formation at the interface between the oil phase and the water phase. Further, the Reactant A was added to the oil phase containing the dimethyl (thio) phosphoric acid type organophosphorus insecticide, and this was dispersed as a droplet in the aqueous phase to which the Reactant B had been added in advance, and then the An interfacial polymerization method that causes film formation at the interface of the aqueous phase may be used.

When Reactant A and the dimethyl (thio) phosphoric acid type organophosphorus insecticide are soluble in each other, a mixture of these two can be directly used as an oil phase, but when they are not soluble in each other, they are mixed with water. Reactant A in difficult organic solvent
It is preferable to use a homogeneous mixture of the three compounds [Reactant A, dimethyl (thio) phosphoric acid type organophosphorus insecticide, solvent] by selecting those capable of dissolving dimethyl (thio) phosphoric acid type organophosphorus insecticide.

Examples of the organic solvent used for this purpose include hydrocarbons such as xylene, toluene, alkylbenzene, phenylxylylethane, hexane and heptane, chlorinated hydrocarbons such as chloroform, methyl ethyl ketone, cyclohexanone, etc. It can be selected from ketones, esters such as diethyl phthalate and n-butyl acetate.

The method for producing a synthetic polymer film by the interfacial polymerization method is described below.

1. When a dimethyl (thio) phosphoric acid type organophosphorus insecticide is included in a polyurethane film: A dimethyl (thio) phosphoric acid type organophosphorus agent is added to an aqueous solution containing a dispersant and a polyhydric alcohol having two or more hydroxyl groups. After dispersing a solution containing one or more insecticides and a polyfunctional isocyanate compound having two or more isocyanate groups, an interfacial polymerization reaction is carried out.

After dispersing a solution containing one or more dimethyl (thio) phosphoric acid type organic phosphorus insecticides and a polyfunctional isocyanate compound having two or more isocyanate groups in an aqueous solution containing a dispersant, the dispersion liquid A polyhydric alcohol having two or more hydroxyl groups is added therein to cause an interfacial polymerization reaction.

2. When a dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in a polyurea film: dimethyl (thio) is added to a dispersant or an aqueous solution containing a polyfunctional amine having two or more amino groups. An interfacial polymerization reaction is carried out after dispersing a solution containing one or more phosphoric acid type organic phosphorus insecticides and a polyfunctional isocyanate compound having two or more isocyanate groups.

After dispersing a solution containing one or more dimethyl (thio) phosphoric acid type organophosphorus insecticides and a polyfunctional isocyanate compound having two or more isocyanate groups in an aqueous solution containing a dispersant, as it is or after A polyfunctional amine having two or more amino groups is added to the dispersion liquid to cause an interfacial polymerization reaction.

3. When a dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in the polyamide film: One or more of the dimethyl (thio) phosphoric acid type organic phosphorus insecticide and two or more in an aqueous solution containing a dispersant. After suspending a mixture with the polyvalent acid chloride having a COCl group, a polyfunctional amine having two or more amino groups is added to cause a polymerization reaction.

4. When a dimethyl (thio) phosphoric acid type organophosphorus insecticide is included in a polyamide-polyurea film: One or more dimethyl (thio) phosphoric acid type organophosphorus insecticides are added to an aqueous solution containing a dispersant. After mixing with a polyvalent acid chloride having two or more COCl groups and further suspending a mixture of polyvalent isocyanates having two or more NCO groups, a polyfunctional having two or more amino groups A reactive amine is added to cause a polymerization reaction.

5. When a dimethyl (thio) phosphoric acid type organophosphorus insecticide is included in a polyester film: One or more dimethyl (thio) phosphoric acid type organophosphorus insecticides and two or more in an aqueous solution containing a dispersant. After suspending a mixture of the polyvalent acid chlorides having COCl groups, the polyhydric alcohol having two or more hydroxyl groups is added to cause polymerization.

6. When a dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in a polycarbonate film: One or more dimethyl (thio) phosphoric acid type organic phosphorus insecticides and phosgene are added to an aqueous solution containing a dispersant. After suspending the mixture, a polyhydric alcohol having two or more hydroxyl groups is added to cause a polymerization reaction.

7. When a dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in the polysulfonate film: One or more dimethyl (thio) phosphoric acid type organic phosphorus insecticides and two pieces in an aqueous solution containing a dispersant. After suspending a mixture of the above polyhydric sulfonyl chlorides having SO ₂ Cl groups, polyhydric alcohols having two or more hydroxyl groups are added,
Cause a polymerization reaction.

8. When a dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in a polysulfonamide type film: One or more dimethyl (thio) phosphoric acid type organic phosphorus insecticides and two or more in an aqueous solution containing a dispersant. After suspending the mixture with the polyvalent sulfonyl chloride having SO ₂ Cl group, a polyfunctional amine having two or more amino groups is added to cause a polymerization reaction.

9. When the dimethyl (thio) phosphoric acid type organic phosphorus insecticide is included in the epoxy resin film: One or more of the dimethyl (thio) phosphoric acid type organic phosphorus insecticide and two pieces in an aqueous solution containing a dispersant. After suspending a mixture of the above polyvalent epoxy compound having an epoxy ring, a polyfunctional amine having two or more amino groups is added to cause a polymerization reaction.

After the encapsulation reaction, the obtained microcapsule dispersion may be put to practical use as it is, or may be diluted with water to a predetermined concentration before use. Practically preferably,
A dispersion stabilizer is added to the dispersion liquid or the diluted liquid of the dispersion liquid to use as a stable slurry type preparation. When an excess of amine is used in the polymerization, it may be neutralized with hydrochloric acid after the reaction.

The reaction time depends on the reaction temperature, but is usually preferably 1 hour or more.

When a solution (hereinafter, referred to as an oil phase) containing one or more kinds of the above-mentioned dimethyl (thio) phosphoric acid type organic phosphorus insecticide is dispersed in an aqueous solution (hereinafter, referred to as an aqueous phase) containing a dispersant or the like. Any of a batch type disperser, a continuous feed type disperser, etc. may be used for this, but the ratio of the oil phase to the water phase at the time of dispersion is the amount of the oil phase to the water phase 1. It is preferably at most 2 or less. If the amount of the oil phase exceeds this, the risk of obtaining a water-in-oil type dispersion system is increased without obtaining the oil-in-water type dispersion system necessary for the microencapsulation reaction. .

Here, with a polyurethane film or polyurea film,
Taking microcapsules of dimethyl (thio) phosphoric acid type organic phosphorus insecticide as an example, microcapsules having an average particle size of 80 μm or less, a film thickness of 0.2 μm or more, and an average particle size / film thickness of 200 or less are prepared. The conditions for obtaining are shown.

It should be noted that the conditions can be basically guided in the same way when microcapsulating with other films.

First during manufacturing amounts to W _NCO parts of polyfunctional isocyanate compound to be charged to the oil phase, the number of isocyanate groups contained its molecular weight during the M _NCO, 1 molecule N _NCO. Then
When a microencapsulation reaction by a polyurethane-based film is carried out using a polyhydric alcohol having a molecular weight of M _OH and the number of hydroxyl groups contained in one molecule, N _OH , at least It is necessary to add parts by weight of polyhydric alcohol.

Also the molecular weight Number of amino groups contained in one molecular weight In the case of carrying out the microencapsulation reaction by the polyurea film using the polyfunctional amine of Addition of parts by weight of multifunctional amine is required.

In addition, when the polyfunctional isocyanate compound reacts with water to form a polyurea-based film, there is usually no particular problem as long as there is sufficient water to disperse the oil phase.

Microcapsules having a thickness (T) is the mean particle diameter d, W _C parts by weight of the amount of core material, W _W parts by weight of the amount of membrane material, the density of the core material [rho _C, the density of the film material [rho _{If W} , then it is approximated by the following equation (1).

Approximation formula (1) When the amount of the oil phase charged at the time of production is Woil, W _C in the approximate expression (1) is expressed by W _C = Woil−W _NCO . Also W _W
When forming a polyurethane film by the reaction of a polyfunctional isocyanate compound and a polyhydric alcohol, When a polyurea-based film is formed by the reaction of a polyfunctional isocyanate compound and a polyfunctional amine, When a polyurea-based film is formed by reacting a polyfunctional isocyanate compound with water, 2 mol of the isocyanate group reacts with 1 mol of H ₂ O to form 1 mol of a urea bond and 1 mol of CO ₂ The molecular weight of H ₂ O is 1
8, the molecular weight of CO ₂ is 44, Therefore, the approximate expression (1) is obtained by the following equation (2) when a polyurethane film is formed by the reaction of a polyfunctional isocyanate and a polyhydric alcohol. When a polyurea-based film is formed by reacting a polyfunctional isocyanate compound with a polyfunctional amine, the approximate formula (3) When a polyurea film-based film is formed by reacting a polyfunctional isocyanate compound with water, the approximate formula (4) Becomes

The film thickness referred to in the present invention is basically an approximate expression (2),
It is calculated using (3) or (4).

Therefore, in order to produce microcapsules having an average particle size of 80 μm or less, a film thickness of 0.2 μm or more, and an average particle size / film thickness of 200 or less, a reaction between a polyfunctional isocyanate compound and a polyhydric alcohol is used. In order to form a polyurethane film, d ≦ 80 μm and T ₁ ≧ 0.2 μ
m and d / T ₁ ≦ 200, when a polyurea film is formed by the reaction of a polyfunctional isocyanate compound and a polyfunctional amine, d ≦ 80 μm and T ₂ ≧ 0.2 μm and d / T ₂ When a polyurea film is formed by a reaction of ≦ 200, a polyfunctional isocyanate and water, the production conditions may be determined so that d ≦ 80 μ, T ₃ ≧ 0.2 μm, and d / T ₃ ≦ 200.

The average particle size of the microcapsules is mainly determined by the type and concentration of the dispersant used for suspension dispersion, and the strength of mechanical stirring during suspension dispersion. For measuring the average particle size, for example, Coulter Counter Model TA
-Type II (handling by Nikkaki) can be used.

 Polyfunctional isoform used in the production of microcapsules
Examples of the cyanate compound include toluene diisocyanate.
Anate, hexamethylene diisocyanate, toluene
Addition of diisocyanate and trimethylolpropane
Self-condensation product of hexamethylene diisocyanate,
Rani Sumidur L (Sumitomo Bayer Urethane Co., Ltd.
Made), Sumidur N (Sumitomo Bayer Urethane Stock Association
Manufactured by the company) and the like.

Examples of the polyhydric alcohol having two or more OH groups generally include ethylene glycol, propylene glycol, butylene glycol, hexanediol, heptanediol, dipropylene glycol, triethylene glycol, glycerin, resorcin, hydroquinone and the like.

Examples of the polyvalent amine having two or more NH ₂ groups include ethylenediamine, hexamethylenediamine, phenylenediamine, toluenediamine, diethylenetriamine and the like.

Examples of the polyvalent acid chloride having two or more COCl groups include sebacyl chloride, terephthaloyl chloride, trimesoyl trichloride and the like.

Examples of the polyvalent sulfonyl chloride having two or more SO ₂ Cl groups include phenylenedisulfonyl chloride.

 A polyepoxy compound having two or more epoxy rings and
For example, an epichlorohydrin derivative [for example,
Smy Epoxy ELA128 (Sumitomo Chemical Co., Ltd.)]
Etc.

As a dispersant for suspending and dispersing an oil phase containing a dimethyl (thio) phosphoric acid type organophosphorus insecticide and a polyfunctional reactant, for example, natural polysaccharides such as gum arabic, semisynthetic compounds such as carboxymethyl cellulose and methyl cellulose are used. Polysaccharides, synthetic polymers such as polyvinyl alcohol, mineral fine powders such as magnesium / aluminum silicate, etc. may be used alone or in admixture of two or more. When the suspension dispersibility is weak, the suspension dispersibility can be improved by adding a known surfactant described in “Synthetic Surfactant” by Hiroshi Horiguchi.

As the dispersion stabilizer of the capsule slurry, the water-soluble polymers listed as the above-mentioned dispersants may be used as they are, but if necessary, natural polysaccharides such as xanthan gum and locust bean gum, carboxymethyl cellulose and the like. The semi-synthetic polysaccharide, the synthetic polymer such as polyacrylic acid sodium salt, and the fine mineral powder such as magnesium / aluminum silicate may be used alone or in combination of two or more as a thickener.

When the composition of the present invention is applied to a forest, the application amount of the dimethyl (thio) phosphoric acid type organophosphorus insecticide as an active ingredient is
(1) 10 to 10,000 g per 10 ares in the case of airborne spraying by aircraft, etc. (2) Trees with a tree height of about 10 m in the case of ground spraying with a power sprayer or local treatment with gun nozzles from the air 1 It is 1 to 1000 g per book, and (3) 0.5 to 50 g per 1 m ^{2 of} tree in the case of treatment of fallen trees or felled trees by application to the trunk or application with a sprayer or preventive treatment of living trees.

<Example> Next, the present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples.

Example 1 Sumidule L (Same as above) 50 g of O, O-dimethyl
 O- (3-methyl-4-nitrophenyl) phosphoroti
Add to 200 g of onate and stir until it becomes a homogeneous solution.
Solution containing 5% by weight of gum arabic as an emulsifying dispersant
In addition to 350 g, T.K.
Using Momixer (trade name of Tokushu Kika Kogyo Co., Ltd.)
Stir for minutes. The rotation speed was 2200 rpm. Then Echi
After dropping 10g of ren glycol into the reaction system, low temperature of 60 ℃
Mike reacts while stirring gently in the tank for 24 hours
A dispersion of the encapsulated product was formed. Zanthangum on this
0.5% by weight, magnesium aluminum silicate 1.0 weight
Add a thickener aqueous solution containing 100% by weight to make the total weight 1000 g
So that the active ingredient concentration is 20% by weight.
A rally was obtained (this composition 1).

The obtained microcapsules had an average particle size of 69 μm and a film thickness of 2.3 μm (average particle size / film thickness) of 30.

Example 2 Sumidule L (Same as above) 50 g of O, O-dimethyl
 O- (3-methyl-4-nitrophenyl) phosphoroti
Add 200 g of oate and stir until it becomes a homogeneous solution.
Solution containing 5% by weight of gum arabic as an emulsifying dispersant
In addition to 350 g, T.K.
Using Momixer (trade name of Tokushu Kika Kogyo Co., Ltd.)
Stir for minutes. The rotation speed was 2800 rpm. Then 60 ℃
When reacting in a constant temperature bath of 24 hours with gentle stirring
A dispersion of microencapsulates formed. Zanta to this
0.5% by weight, 1.0% by weight magnesium silicate
Add an aqueous solution of thickener containing it to make the total weight 1000g.
Adjusted so that the active ingredient concentration is 20% by weight capsule slurry
Was obtained (this composition 2).

The average particle size of the obtained microcapsules was 59 μm, the film thickness was 1.8 μm, and (average particle size / film thickness) was 33.

Example 3 Sumidule L Since the amount of (same as above) is 100g,
Otherwise, the same operation as in Example 2 was performed, and the active ingredient concentration was 20
A quantity% capsule slurry was obtained (present composition 3).

The average particle size of the obtained microcapsules was 62 μm, the film thickness was 3.5 μm, and the (average particle size / film thickness) was 18.

Example 4 Sumidule L Sumiju instead of (same as above)
Room N (Same as above) and increase the amount to 50g.
Rotor homomixer (same as above) to 3000 rpm
The same operation as in Example 1 was performed except that the active ingredient concentration was increased.
A 20% by weight capsule slurry was obtained (composition 4).

The average particle size of the obtained microcapsules was 52 μm, the film thickness was 1.8 μm, and (average particle size / film thickness) was 29.

Example 5 Sumidule L Sumiju instead of (same as above)
Room N (Same as above) and increase the amount to 50g.
Rotor homomixer (same as above) to 3000 rpm
The same operation as in Example 2 was performed except that the
A 20% by weight capsule slurry was obtained (composition 5).

The average particle size of the obtained microcapsules was 54 μm, the film thickness was 1.6 μm, and the (average particle size / film thickness) was 34.

Example 6 Sumidur N Since the amount of (same as above) is 100g,
The same procedure as in Example 5 was carried out except that the active ingredient concentration was 20
A quantity% capsule slurry was obtained (composition 6).

The average particle size of the obtained microcapsules was 56 μm, the film thickness was 3.2 μm, and (average particle size / film thickness) was 18.

Example 7 The rotation speed of the TK auto homomixer (same as above) was set to 35.
The same operation as in Example 2 was carried out except that the speed was changed to 00 rpm to obtain a capsule slurry having an active ingredient concentration of 20% by weight (the present composition 7).

The obtained microcapsules had an average particle size of 47 μm, a film thickness of 1.4 μm, and (average particle size / film thickness) of 34.

Example 8 Sumidule L Since the amount of (same as above) is 100g,
Otherwise, the same operation as in Example 7 was performed to obtain an active ingredient concentration of 20
A quantity% capsule slurry was obtained (composition 8).

The average particle size of the obtained microcapsules was 39 μm, the film thickness was 2.2 μm, and (average particle size / film thickness) was 18.

Example 9 Sumidule L Since the amount of (same as above) is 150g,
Otherwise, the same operation as in Example 7 was performed to obtain an active ingredient concentration of 20
A quantity% capsule slurry was obtained (composition 9).

The average particle size of the obtained microcapsules was 32 μm, the film thickness was 2.6 μm, and (average particle size / film thickness) was 12.

Example 10 Sumidur N (Same as above) to 50g, T.K.
Rotation speed of auto homomixer (same as above) is 3500 rpm
The same operation as in Example 5 was carried out except that
A capsule slurry having a concentration of 20% by weight was obtained (this composition 1
0).

The average particle size of the obtained microcapsules was 44 μm, the film thickness was 1.3 μm, and the (average particle size / film thickness) was 34.

Example 11 Sumidur N Since the amount of (same as above) is 100g,
Outside, the same operation as in Example 10 was performed, and the active ingredient concentration was 20
A quantity% capsule slurry was obtained (composition 11).

The average particle size of the obtained microcapsules was 45 μm, the film thickness was 2.5 μm, and (average particle size / film thickness) was 18.

Example 12 Sumidur N Since the amount of (same as above) is 150g,
Outside, the same operation as in Example 10 was performed, and the active ingredient concentration was 20
A quantity% capsule slurry was obtained (this composition 12).

The average particle size of the obtained microcapsules was 40 μm, the film thickness was 3.2 μm, and (average particle size / film thickness) was 13.

Example 13 Sumidule L (Same as above) to 30g, T.K.
Rotation speed of auto homomixer (same as above) is 5600 rpm
The same operation as in Example 2 was carried out except that
A capsule slurry having a concentration of 20% by weight was obtained (this composition 1
3).

The average particle size of the obtained microcapsules was 22 μm, the film thickness was 0.4 μm, and (average particle size / film thickness) was 55.

Example 14 The rotation speed of the TK auto homomixer (same as above) was set to 56.
The same operation as in Example 2 was carried out except that the speed was changed to 00 rpm to obtain a capsule slurry having an active ingredient concentration of 80% by weight (the present composition 14).

The average particle size of the obtained microcapsules was 21 μm, the film thickness was 0.6 μm, and (average particle size / film thickness) was 35.

Example 15 Sumidule L (Same as above) to 100g, T.K.
Rotation speed of auto homomixer (same as above) is 5600 rpm
The same operation as in Example 2 was carried out except that
A capsule slurry having a concentration of 20% by weight was obtained (this composition 1
Five).

The average particle size of the obtained microcapsules was 21 μm, the film thickness was 1.2 μm, and (average particle size / film thickness) was 18.

Example 16 Sumidule L (Same as above) 50 g O- (4-shi
Anophenyl) O, O-dimethyl phosphorothioate 200
Add to g and stir until it becomes a uniform solution, which is 5% by weight
Added to 350 g of an aqueous solution containing gum arabic as an emulsifying dispersant.
T.K. auto homomixer until it becomes microdroplets at room temperature
(Tokushu Kika Kogyo Co., Ltd.) and stir for a few minutes
Was. The rotation speed was 5600 rpm. Then propylene glycol
After dropping 10 g of coal into the reaction system,
If the reaction is performed with gentle stirring for a while, the microcapsule
A dispersion of the chloride was formed. Carboxymethyl cell
Loin [Serogen 3H (Daiichi Kogyo Seiyaku Co., Ltd.)] Quadruple
Add a thickener aqueous solution containing 100% by weight to make the total weight 1000 g
So that the active ingredient concentration is 20% by weight.
A rally was obtained (this composition 16).

The obtained microcapsules had an average particle size of 22 μm and a film thickness of 1.4 μm (average particle size / film thickness) of 16.

Example 17 Sumidur L (Same as above) 50 g of S- [1,2-bi
Sus (ethoxycarbonyl) ethyl O, O-dimethylpho
Add 200 g of Sforodithioate and stir until a homogeneous solution is obtained.
Stir and use 5 wt% gum arabic as an emulsifying dispersant
Add it to 350 g of the aqueous solution containing it and add T.
K. Auto Homo Mixer (trade name of Tokushu Kika Kogyo Co., Ltd.)
And stirred for several minutes. The rotation speed was 5600 rpm.
After adding ethylene glycol g into the reaction system,
React in a 60 ° C constant temperature bath for 24 hours with gentle stirring.
Then, a dispersion liquid of the microencapsulated product was formed. To this
0.75% by weight tan gum, magnesium aluminum sili
Add an aqueous solution of thickener containing 1.5 wt%
Adjust the amount to 1000g, 20% by weight active ingredient concentration
A capsule slurry of was obtained (this composition 17).

The average particle size of the obtained microcapsules was 20 μm, and the film thickness was 1.2 μm (average particle size / film thickness).

Comparative Example 1 Sumidule L Since the amount of (same as above) is 10g,
Otherwise, the same operation as in Example 15 was performed, and the active ingredient concentration was 20
A quantity% capsule slurry was obtained (Comparative composition 1).

The average particle size of the obtained microcapsules was 23 μm, the film thickness was 0.15 μm, and (average particle size / film thickness) was 153.

Comparative Example 2 Sumidule L Except that the amount of (same as above) is 7g
Carried out the same operation as in Comparative Example 1, and the active ingredient concentration was 20% by weight.
% Capsule slurry was obtained (Comparative composition 2).

The average particle size of the obtained microcapsules was 21 μm, the film thickness was 0.09 μm, and (average particle size / film thickness) was 233.

Comparative Example 3 The rotation speed of the TK auto homomixer (same as above) was set to 15
The same operation as in Example 2 was carried out except that the speed was changed to 00 rpm to obtain a capsule slurry having an active ingredient concentration of 20% by weight (Comparative composition 3).

The average particle size of the obtained microcapsules was 85 μm, the film thickness was 2.6 μm, and (average particle size / film thickness) was 33.

Comparative Example 4 An O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate emulsion having an active ingredient concentration of 50% by weight was produced by a conventional method according to the following formulation (Comparative Composition-4).

O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate 50 parts by weight Solport SM-100P 10 parts by weight (Toho Kagaku registered trademark: mixture of nonionic surfactant and anionic surfactant) ) Xylene Residual 100 parts by weight Comparative Example 5 According to the following formulation, an O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate emulsion having an active ingredient concentration of 80% by weight was produced by a conventional method (comparative composition). Object 5).

O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate 80 parts by weight Solport 355 20 parts by weight (TOHO CHEMICAL registered trademark: mixture of nonionic surfactant and anionic surfactant) Total 100 parts by weight Test Example 1 O, O-dimethyl selected in advance by applying a 100-fold dilution of Comparative Composition 4 to cypress foliage.
Hinoki cypress branches that are sensitive to O- (3-methyl-4-nitrophenyl) phosphorothioate and exhibit defoliation are cut, and these are used as 40-fold diluted solutions of Compositions 1 to 6 and Comparative Composition 4
The sample was dipped in a 100-fold diluted solution of and then put in a 100 ml glass bottle and stored. In the survey, the weight of the foliage was measured before the treatment, and after 7 days from the treatment, the foliage was manually wiped and the weight of the fallen leaves was investigated.
The test was conducted in a room at 25 ° C ± 2 ° C, and the average of two repetitions of one drug was obtained. The results are shown in Table-1.

As a result, all of the present compositions were found to have a clear defoliation prevention effect as compared with the comparative composition.

Test Example 2 Using Chinese cabbage (warrior) seedlings that had been seeded for about 2 weeks, 12.5-fold diluted solutions of Compositions 7 to 12 and 4000 of Comparative Composition 5 were used.
A sufficient amount of the double dilution was sprayed using a spray gun. Scatter 3
After a day, the phytotoxicity of Chinese cabbage was evaluated according to the following criteria, and the phytotoxicity index was calculated by the following formula. The experiment was conducted in a greenhouse, and an average of 3 replicates of 1 drug was obtained. The results are shown in Table-2.

Chemical damage degree (class) (degree) 0… Healthy 1… Necrotic spot area ratio 5% or less 2… Necrotic spot area ratio 6 to 30% 3… Necrotic spot area ratio 31 to 60% 4… Necrotic spot area ratio 61-80% 5 ... Area ratio of necrotic spots 81-100% Although the composition had a 20-fold higher concentration of active ingredient than the comparative composition, the phytotoxicity against Chinese cabbage was significantly reduced.

This result indicates that the present composition extremely suppresses the release of the core substance outside the microcapsules by being microencapsulated. Inhibition of phytotoxicity to cypress is also brought about by inhibition of release of core substance from microcapsules. However, such an effect is not obtained only by microencapsulation, but the film thickness of the microcapsule,
It is shown below that the viscous diameter and the particle diameter / film thickness ratio must be within a certain range.

Test Example 3 By the same method as in Test Example 2, a chemical damage test on Chinese cabbage was performed using the present compositions 13 to 15, comparative compositions 1 to 3 and comparative composition 5. The results are shown in Table-3.

Although the composition had a 20-fold higher concentration of active ingredient than Comparative Composition 5, the phytotoxicity to Chinese cabbage was significantly reduced. In addition, the comparative compositions 1 and 2 were not sufficiently effective in preventing chemical damage, even though they were microencapsulated. That is, the film thickness of the comparative composition 1 is not sufficient, and the film thickness and (average particle size / film thickness) of the comparative composition 2 are small.
This is because the ratio was not suitable. On the other hand, Comparative Composition 3
However, since the particle size was too large, the sedimentation when diluted with water was too fast to carry out the test. That is, if the average particle size is too large, it cannot be practically used.

Test Example 4 A phytotoxicity-preventing test was carried out using a hinoki cypress tree that was actually susceptible. The test method and results are as follows.

Test site Hinoki cypress forest in Machida city, Tokyo Date of treatment May 10, 1985 Test tree No.2, No.9, No.11, No.12, No.16, No.19 Composition 5 This composition 2 Comparative composition 5 (No.9, No.11, No.19 only) Dispersion concentration 0.5% Dispersion method Select an appropriate branch from each test tree, one branch and one drug to the branch tip Scatter to the extent that it gets wet.

Survey results As shown in Table-4.

Test Example 5 A post-meal prevention test was actually carried out using the pine wood beetle.

 The test method and results are as follows.

Reagents (Name of active ingredient) Composition 2 Composition 3 Composition 5 Comparative composition 5 Dispersion concentration 0.5% Drug application date May 27, 1985 Application amount 1/5 Specimen black pine (Approximately 2 m in height, using 5 medicines) Test insects Matsunomadara chamomile adults Number of test insects: 10 per test section (5 for each of ♂ and ♀, but 8 for the comparative composition 5 8th week) Test Results The mortality (%) is shown in Table-5 to Table-6.

Compared to the comparative composition, each of the compositions has an excellent insecticidal effect against Pseudomonas aeruginosa and has a longer residual effect. The effect of preventing post-eating on pine wood beetle was also sufficient.

<Effects of the Invention> As described above, the organophosphorus insecticidal composition for controlling forest pests according to the present invention maintains a very excellent insecticidal effect and prevents the foliage phenomenon against certain cypress trees, and pine forests and cypress forests. Can be used for forests etc.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiro Otsubo 4-2-1 Takashi Takarazuka-shi, Hyogo Sumitomo Kagaku Kogyo Co., Ltd. (72) Inventor Yukio Sanbe 4-2-1 Takashi Takarazuka-shi, Hyogo Prefecture No. Sumitomo Kagaku Kogyo Co., Ltd. (72) Inventor Kumi Takeda 636-2 Shionoyama, Kishiro-cho, Kasai City, Hyogo Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Shozo Sakai Misawa, Aomori Prefecture Sumitomo Chemical Industry Co., Ltd. (72) Inventor Nori Kasamatsu Kishiro-cho, Kasai City, Hyogo Prefecture 636-2 Shionoyama, Sumitomo Chemical Co., Ltd. (72) Inventor Katsunosuke Shimizu Kishiro Town, Kasai City, Hyogo Prefecture 636-2 Shionoyama Sumitomo Chemical Co., Ltd. (72) Inventor, Kozo Tsuji, 3-98 Kasugadaka, Konohana-ku, Osaka-shi, Osaka Rein Imamura, Inspector, Sumitomo Chemical Co., Ltd.

Claims (5)

[Claims] 1. A polymer film having an average particle size of 80 μm or less and a film thickness of 0.2 μm or more, and (average particle size / film thickness) of 200 or less, in a dimethyl (thio) phosphoric acid type organic phosphorus. A microencapsulated insecticidal composition for controlling forest pests, which comprises a system insecticide. 2. The insecticidal composition according to claim 1, wherein the polymer film is a polyurethane film. 3. The insecticidal composition according to claim 1, wherein the polymer film is a polyurea film. 4. A dimethyl (thio) phosphoric acid type organophosphorus insecticide which is O, O-dimethyl O- (3-methyl-4-nitrophenyl) phosphorothioate.
Insecticide composition. 5. A dimethyl (thio) phosphoric acid-type organic phosphorus in a polymer film having an average particle size of 80 μm or less, a film thickness of 0.2 μm or more, and (average particle size / film thickness) of 200 or less. A method for controlling forest pests, which comprises using a microencapsulated insecticidal composition containing a system insecticide.