A kind of dimethoate granules and preparation method thereof

Abstract

The invention relates to the technical field of insecticides, in particular to a dimethoate particle and a preparation method thereof. The particle can effectively act on the range of mosquito larvae activities for a long time through the connection and binding of fiber filaments, thereby improving the long-term insecticidal effect. The particle comprises the following components: a slow-release component, a fast-acting component, a solvent, an emulsifier, a dispersant, a slow-release film-forming agent, a fast-release film-forming agent, an adsorbent, a fiber ball and a corncob particle. The solvent, the emulsifier and the dispersant are used to dissolve the slow-release component and the fast-acting component. The slow-release component is adsorbed in the corncob particle, the slow-release forming film wraps the corncob particle, the fiber ball adheres to the slow-release film-forming agent, the fast-acting component is wrapped on the slow-release forming film and the fiber ball, and the fast-release film-forming agent is wrapped outside the fast-acting component. The slow-release component is Bacillus thuringiensis subspecies israelensis Bti or pyriproxyfen; and the fast-acting component is dimethoate.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, in particular to a dimethoate granule and a preparation method thereof. Background Art

[0002] Temefos is an organic substance with the chemical formula C16H20O6P2S3. It is a white crystalline solid, highly toxic, and is an organophosphorus larvicide used to treat waters infested with disease-transmitting insects, including mosquitoes, midges, and black fly larvae. Temefos affects the central nervous system by inhibiting cholinesterase, causing the larvae to die before reaching the adult stage.

[0003] Since bispyribac has a fast onset of action, a short duration of action, and rapid development of drug resistance, it is often used as a quick-acting insecticide. In order to achieve the purpose of simultaneously and quickly killing mosquito and fly larvae to reduce insect population density, and long-term inhibition of larval growth, completely killing remaining larvae or preventing them from emerging, short-acting insecticides and long-acting insecticides are often combined to form composite particles. For example, a sanitary insecticide granule and a preparation method thereof proposed in application number "CN201710616294.4" uses a slow-acting agent Bacillus thuringiensis subspecies israelensis Bti or pyriproxyfen as the granule core, and bispyribac as the outer layer of the granule, forming a sanitary insecticide granule that can achieve both quick-release and slow-release effects;

[0004] In actual use, the fast-acting outer layer of the composite particles will quickly dissolve in the water and take effect, while the slow-release core will sink to the bottom of the water or drift with the current. Some particles that sink to the bottom of the water will be buried by mud and sand, and mosquito larvae mostly move in the shallow layer near the water surface. The drug concentration released at the bottom of the water is not enough to kill the mosquito larvae. Some particles that drift with the current will move away from the water area where the drug is applied and lose their insecticidal effect in the water area where the drug is applied. As a result, the existing slow-release long-acting agents of the composite particles cannot effectively act on the range of mosquito larvae activities, resulting in poor long-acting insecticidal effect. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a dimethoate granule and a preparation method thereof, which improves the long-term insecticidal effect by connecting and binding the fibers so that the granule can effectively act on the mosquito larvae activity range for a long time.

[0006] A dimethoate granule of the present invention, the dimethoate granule is composed of the following components by weight:

[0007] Sustained release ingredients 1-10%

[0008] Fast-acting ingredients 1-10%

[0009] Solvent 1-20%

[0010] Emulsifier 1-5%

[0011] Dispersant 0.5-5.0%

[0012] Sustained release film former 0.5-5.0%

[0013] Immediate release film former 0.5-5.0%

[0014] Adsorbent 0.5-10%

[0015] Fiber balls 1-5%

[0016] Corn cob pellets to 100%

[0017] The solvent, emulsifier and dispersant are used to dissolve the slow-release component and the quick-acting component. The slow-release component is adsorbed in the corn cob particles, the slow-release forming film wraps the corn cob particles, the fiber balls are adhered to the slow-release forming film, the quick-acting component is wrapped on the slow-release forming film and the fiber balls, and the quick-release film-forming agent is wrapped outside the quick-acting component; the slow-release component is Bacillus thuringiensis subspecies israeli Bti or pyriproxyfen; the quick-acting component is dimethoate; when in use, the dimethoate particles are thrown into the water, and the quick-release film-forming agent encounters Water decomposition causes the dimethoate to quickly dissolve into the shallow layer near the water surface, quickly killing mosquito larvae. At the same time, the fiber balls in the dimethoate come into contact with water, and the fibers of the fiber balls unfold under the action of the water flow, so that the fiber threads between the particles are connected to each other, and the fiber threads will be entangled on the aquatic plants, so that the sustained-release component core of the particles is in the activity area of ​​​​the mosquito larvae, and the particles will not sink to the bottom of the water or drift with the current. The sustained-release long-acting agent in the particles can effectively act on the range of mosquito larvae activities for a long time, thereby improving the long-acting insecticidal effect.

[0018] Preferably, the fiber balls are made of cotton fiber or hemp fiber; cotton fiber and hemp fiber are biological fibers, which are biodegradable, do not pollute the environment, and can be kept in water for a long time.

[0019] Preferably, the sustained-release film-forming agent is a high molecular weight hydrophobic polymer, such as polyvinyl acetate; the hydrophobic polymer is not easily soluble in water, and as a film-forming agent, it can effectively wrap up the sustained-release agent in the corncob particles, achieving the purpose of slow release.

[0020] Preferably, the rapid-release film-forming agent is a water-soluble polymer, such as one or more of hydroxyethyl cellulose, pregelatinized starch, and gum arabic; the water-soluble polymer is easily soluble in water, and as a film-forming agent, it can dissolve rapidly after encountering water, and release the dimethoate encapsulated therein into the water during the sinking process of the particles, thereby achieving the purpose of rapid release of the drug effect.

[0021] Preferably, the solvent is one of tributyl phosphate, tributyl citrate, and acetyl tributyl citrate; the above solvent can effectively dissolve the sustained-release component and the fast-acting component, and is low-toxic, odorless, non-irritating, and has good safety.

[0022] Preferably, the emulsifier is one or more of calcium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether; the dispersant is polycarboxylate or lignin sulfonate; the emulsifier and the dispersant are used in combination to disperse the components in the sustained-release component solution and the fast-acting component solution that are difficult to dissolve in the solution and are immiscible with each other, and the solution forms a stable emulsion.

[0023] Preferably, the adsorbent is white carbon black or attapulgite; the adsorbent is mixed with the fast-acting component solution to form a mixed powder, which is convenient for wrapping on the drug core of the sustained-release component.

[0024] A method for preparing dimethoate granules of the present invention comprises:

[0025] Step 1: Rub the cotton fiber or hemp fiber into uniform small balls;

[0026] Step 2: Divide the solvent, emulsifier and dispersant into two parts, dissolve the slow-release component in one part of the solvent, add one part of the emulsifier and one part of the dispersant and mix well, then add the above liquid to the corn cob particles for full adsorption, then add the slow-release film-forming agent and roll the coating in a drum granulator, when the coating thickness is 0.1 to 0.2 mm, add the fiber balls obtained in step 1, continue coating to 0.3 to 0.5 mm, and dry to obtain the slow-release kernel particles with fiber balls for later use;

[0027] Step 3, dissolving the quick-acting component in one part of a solvent, adding one part of an emulsifier and one part of a dispersant, stirring evenly, and adsorbing the mixture into a powder using the adsorbent;

[0028] Step 4: Put the sustained-release core particles with fiber balls obtained in step 2 into a drum granulator, add the powder obtained in step 3 into the drum granulator, make the powder fully wrap the core particles, and add a quick-release film-forming agent for rolling coating;

[0029] Step 5: Drying the particles obtained in step 4.

[0030] Compared with the prior art, the invention has the following beneficial effects: when in use, the dimethoate particles are thrown into the water area, the quick-release film-forming agent decomposes when in contact with water, so that the dimethoate is quickly dissolved in the shallow layer close to the water surface, and the mosquito larvae are quickly killed; at the same time, the fiber balls in the dimethoate are in contact with water, and the fibers of the fiber balls are unfolded under the action of the water flow, so that the fiber filaments between the particles are connected to each other, and the fiber filaments are entangled on the water plants, so that the sustained-release component drug core of the particles is in the activity area of ​​the mosquito larvae, and the particles will not sink to the bottom of the water nor drift with the current, and the sustained-release long-acting agent of the particles can effectively act on the range of mosquito larvae activities for a long time, thereby improving the long-acting insecticide effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the dimethoate granules in the present invention;

[0032] Figure 2 It is a schematic diagram of the cross-sectional structure of the dimethoate particles in the present invention;

[0033] Markings in the attached figure: 1. drug core; 2. sustained-release coating; 3. fiber ball; 4. fast-acting drug layer; 5. fast-release coating. DETAILED DESCRIPTION

[0034] In order to facilitate understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0035] Preparation Example 1

[0036] Dissolve 0.5 ml of 80000 IU / ml Bacillus thuringiensis subsp. israelensis suspension in an appropriate amount of water containing 2 g of polycarboxylate dispersant, fully roll and adsorb the liquid with an appropriate amount of white carbon black particles in a drum granulator for 35 minutes, then add a diluent containing 3 g of polyvinyl acetate, fully roll and coat for 15 minutes, at which time the coating thickness is 0.1 to 0.2 mm, add cotton fiber balls, continue rolling and coating for 20 minutes, until the coating thickness is 0.3 to 0.5 mm, and dry to obtain cotton fiber sustained-release kernel particles for use;

[0037] Dissolve 2.0 g of dimethoate in 2.0 g of tributyl phosphate, add 1 g of calcium dodecylbenzene sulfonate as an emulsifier and stir evenly, mix evenly with 0.4 g of a polycarboxylate dispersant dissolved in an appropriate amount of water, adsorb with 4.0 g of white carbon black, roll and coat thoroughly with the above-mentioned cotton fiber sustained-release core particles in a drum granulator for 20 minutes, then add a diluent containing 0.4 g of gum arabic and continue rolling and coating for 15 minutes, and dry to obtain 200 g of 2% dimethoate granules containing 200 IU / g Bacillus thuringiensis.

[0038] Preparation Example 2

[0039] Dissolve 0.5 ml of 80000 IU / ml Bacillus thuringiensis subsp. israelensis suspension in an appropriate amount of water containing 2 g of polycarboxylate dispersant, fully roll and adsorb the liquid with an appropriate amount of white carbon black particles in a drum granulator for 35 min, then add a diluent containing 3 g of polyvinyl acetate, roll and coat for 15 min, at which time the coating thickness is 0.1 to 0.2 mm, add hemp fiber balls, continue rolling and coating for 20 min, make the coating thickness 0.3 to 0.5 mm, dry to obtain hemp fiber sustained-release core particles for use;

[0040] Dissolve 2.0 g of dimethoate in 2.0 g of tributyl phosphate, add 1 g of calcium dodecylbenzene sulfonate as an emulsifier and stir evenly, mix evenly with 0.4 g of a polycarboxylate dispersant dissolved in an appropriate amount of water, adsorb with 4.0 g of white carbon black, roll and coat thoroughly with the above-mentioned hemp fiber sustained-release core particles in a drum granulator for 20 minutes, then add a diluent containing 0.4 g of gum arabic and continue rolling and coating for 15 minutes, and dry to obtain 200 g of 2% dimethoate granules containing 200 IU / g Bacillus thuringiensis.

[0041] Comparative Example 1

[0042] Dissolve 0.5 ml of 80000 IU / ml Bacillus thuringiensis subsp. israelensis suspension in an appropriate amount of water containing 2 g of polycarboxylate dispersant, fully roll and adsorb the liquid with an appropriate amount of white carbon black particles in a drum granulator for 35 minutes, then add a diluent containing 3 g of polyvinyl acetate, fully roll and coat for 35 minutes, at which time the coating thickness is 0.3 to 0.5 mm, and dry to obtain the sustained-release core particles for use;

[0043] Dissolve 2.0 g of dimethoate in 2.0 g of tributyl phosphate, add 1 g of calcium dodecylbenzene sulfonate as an emulsifier and stir evenly, mix evenly with 0.4 g of a polycarboxylate dispersant dissolved in an appropriate amount of water, adsorb with 4.0 g of white carbon black, roll and coat thoroughly with the above-mentioned hemp fiber sustained-release core particles in a drum granulator for 20 minutes, then add a diluent containing 0.4 g of gum arabic and continue rolling and coating for 15 minutes, and dry to obtain 200 g of 2% dimethoate granules containing 200 IU / g Bacillus thuringiensis.

[0044] Comparative Example 2

[0045] Dissolve 0.5 ml of 80000 IU / ml Bacillus thuringiensis subsp. israelensis suspension in an appropriate amount of water containing 2 g of polycarboxylate dispersant, dissolve 2.0 g of dimethoate in 2.0 g of tributyl phosphate, add 1 g of calcium dodecylbenzene sulfonate as an emulsifier and stir evenly, mix with 0.4 g of polycarboxylate dispersant dissolved in an appropriate amount of water, mix the above two liquids and put them into a drum granulator, use an appropriate amount of white carbon black particles to fully roll and adsorb for 35 minutes, then add a diluent containing 0.4 g of gum arabic, roll and coat for 35 minutes, make the coating to 0.3 to 0.5 MM, and dry to obtain 200 g of 2% dimethoate granules containing 200 IU / g Bacillus thuringiensis and.

[0046] Application Example: Indoor efficacy test for controlling mosquito larvae

[0047] Test method:

[0048] At the bottom of a glass tube with a depth of one meter, 10CM thick soil was laid and 70CM high aquatic plants were planted. 10L of dechlorinated tap water was added to the glass tube, and 30 healthy third-instar larvae were put in. They were raised according to the normal method, and the preparation was evenly applied at a dosage of 20g / m3 without stirring. After the preparation was applied, the 2h mortality rate and 96h mortality rate were observed; the experiment was repeated three times, and a blank control was set.

[0049] During the test, the test water was replenished to the initial water volume mark at intervals of 2 days.

[0050] Observation of effective period: Add 30 third-instar larvae to the test group and blank control group on the 1st, 15th, 30th, 60th, 90th and 120th day respectively, and observe the test results according to the above steps.

[0051] The test data are as follows:

[0052] Table-1 Comparison of the efficacy of bispyribac granules with fiber balls and bispyribac granules without fiber balls on mosquito larvae

[0053]

[0054] Table-1

[0055] It can be seen from the efficacy data in Table 1 that, compared with the dimethoate granules without fiber balls, the two dimethoate granules with fiber balls prepared by the present invention are mostly hung on aquatic plants due to the entanglement effect of fiber filaments, and the medicine released by the granules covers the main activity area of ​​the striped larvae, and the high insecticide rate is always maintained in the long-term experiment. The insecticide rate of the medicine prepared in Comparative Example 1 begins to decrease in the middle and late stages of the experiment due to the slow-release core wrapped with a slow-release membrane, and the insecticide rate of the medicine prepared in Comparative Example 2 begins to decrease in the middle stage of the experiment due to the lack of a slow-release core wrapped with a slow-release membrane.

[0056] This indicates that the bispyribac granules with fiber balls prepared by the present invention have obvious advantages in long-term insecticidal rate compared with the bispyribac granules without fiber balls.

[0057] like Figure 1 to Figure 2 As shown, a dimethoate granule of the present invention, when working, firstly, the dimethoate granule is thrown into the water area, and the quick-release coating 5 decomposes when it meets water, and then the dimethoate in the quick-acting drug layer 4 is quickly dissolved into the shallow layer near the water surface, and the mosquito larvae are quickly killed, and then the fiber ball 3 contacts with water, and the fibers of the fiber ball 3 are unfolded under the action of the water flow, so that the fiber filaments between the particles are connected to each other, and the fiber filaments will be entangled on the water plants, and finally the drug core 1 of the granule is in the activity area of ​​the mosquito larvae, and the Bacillus thuringiensis israelensis subspecies Bti or pyriproxyfen in the drug core 1 is slowly released into the water through the sustained-release coating 2.

[0058] The main function achieved by the present invention is: through the connection and binding of the fiber filaments, the particles can effectively act on the range of mosquito larvae activities for a long time, thereby improving the long-term insecticidal effect.

[0059] The installation, connection or setting methods of the dimethoate granules and the preparation method thereof of the present invention are all common methods, and any method that can achieve its beneficial effects can be implemented; the sustained-release component, quick-acting component, solvent, emulsifier, dispersant, sustained-release film-forming agent, quick-release film-forming agent, adsorbent, and corn cob granules of the dimethoate granules of the present invention are purchased on the market, and technicians in the industry only need to apply them according to the accompanying instructions for use, without the need for creative labor by technicians in the field.

[0060] All technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dimethoate granule; characterized in that: The dimethoate granules are composed of the following components by weight: Sustained release ingredients 1-10% Fast-acting ingredients 1-10% Solvent 1-20% Emulsifier 1-5% Dispersant 0.5-5.0% Sustained release film former 0.5-5.0% Immediate release film former 0.5-5.0% Adsorbent 0.5-10% Fiber balls 1-5% Corn cob pellets to 100% The solvent, emulsifier and dispersant are used to dissolve the slow-release component and the fast-acting component. The slow-release component is adsorbed in the corn cob particles, the slow-release formed film wraps the corn cob particles, the fiber balls are adhered to the slow-release formed film-forming agent, the fast-acting component is wrapped on the slow-release formed film and the fiber balls, and the fast-release film-forming agent is wrapped outside the fast-acting component; the slow-release component is Bacillus thuringiensis subspecies israelensis Bti or pyriproxyfen; the fast-acting component is dimethoate.

2. The dimethoate granules according to claim 1, characterized in that: The fiber ball is made of cotton fiber or hemp fiber.

3. The dimethoate granules according to claim 1, characterized in that: The sustained-release film-forming agent is a high-molecular-weight hydrophobic polymer, and the high-molecular-weight hydrophobic polymer is polyvinyl acetate.

4. The dimethoate granules according to claim 1, characterized in that: The quick-release film-forming agent is a water-soluble high molecular polymer, and the water-soluble high molecular polymer is one or more of hydroxyethyl cellulose, pregelatinized starch, and gum arabic.

5. The dimethoate granules according to claim 1, characterized in that: The solvent is one of tributyl phosphate, tributyl citrate and acetyl tributyl citrate.

6. The dimethoate granules according to claim 1, characterized in that: The emulsifier is one or more of calcium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether; and the dispersant is polycarboxylate or lignin sulfonate.

7. The dimethoate granules according to claim 1, characterized in that: The adsorbent is white carbon black or attapulgite.

8. A method for preparing dimethoate granules according to any one of claims 1 to 7, comprising: Step 1: Rub the cotton fiber or hemp fiber into uniform small balls; Step 2: Divide the solvent, emulsifier and dispersant into two parts, dissolve the slow-release component in one part of the solvent, add one part of the emulsifier and one part of the dispersant and mix well, then add the above liquid to the corn cob particles for full adsorption, then add the slow-release film-forming agent and roll the coating in a drum granulator, when the coating thickness is 0.1 to 0.2 mm, add the fiber balls obtained in step 1, continue coating to 0.3 to 0.5 mm, and dry to obtain the slow-release kernel particles with fiber balls for later use; Step 3, dissolving the quick-acting component in one part of a solvent, adding one part of an emulsifier and one part of a dispersant, stirring evenly, and adsorbing the mixture into a powder using the adsorbent; Step 4: Put the sustained-release core particles with fiber balls obtained in step 2 into a drum granulator, add the powder obtained in step 3 into the drum granulator, make the powder fully wrap the core particles, and add a quick-release film-forming agent for rolling coating; Step 5: Drying the particles obtained in step 4.

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