A water dispersible granule containing thiamethoxam and chlorfenapyr and a preparation method thereof

Abstract

The present invention relates to the technical field of agricultural pesticides, and more particularly to a water-dispersible granule comprising thiamethoxam and cyhalothrin and a preparation method thereof, wherein the water-dispersible granule is composed of an active pesticide component, a dispersant, a disintegrant, a foliar adhesive, a binder and a filler. The combined use of thiamethoxam, cyhalothrin and catechin in the active pesticide component can achieve a synergistic effect, effectively enhancing the control effect; the cardanol-modified hydroxyethyl cellulose component in the foliar adhesive has hard water resistance and wetting and adhesion performance, which is conducive to regulating the dispersion and suspension effect of the water-dispersible granule in hard water and the wetting and spreading effect of droplets after spraying, and the L-ascorbyl palmitate component in the foliar adhesive is conducive to improving the adhesion and retention rate of the water-dispersible granule after being sprayed on the leaf surface, so that the active pesticide component is better adhered to the plant surface, and the loss caused by rainwater scouring is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural pesticides, and more particularly to a water dispersible granule containing thiamethoxam and chlorfenapyr and a preparation method thereof. Background Art

[0002] Thiamethoxam is a nicotinic acetylcholine receptor agonist with stomach poison, contact and systemic activity. It has good preventive effect on piercing-sucking pests such as aphids, and can replace highly toxic and long-residual organophosphorus, organochlorine and carbamate insecticides. Chlorfluthrin belongs to the pyrethroid insecticide, which has high insecticidal activity. Compared with some traditional pesticides, chlorfluthrin has less impact on the environment and is less toxic to mammals, so it is a low-toxic pesticide. In the prior art, the combined use of thiamethoxam and chlorfluthrin can achieve the benefits of synergistic enhancement and rapid onset of action.

[0003] At present, water-dispersible granules containing thiamethoxam and chlorflucythrinate are mainly composed of thiamethoxam, chlorflucythrinate, dispersants, wetting agents, disintegrants, binders, fillers and other components. The selection of adjuvants is a key factor affecting the wettability and suspension of water-dispersible granules, which affects the retention amount and retention time of the drug solution on the plant surface, and further affects the utilization effect of thiamethoxam and chlorflucythrinate. Most of the adjuvants in the prior art can only play a relatively simple role in improving the wettability, suspension or disintegration performance of the water-dispersible granules, but cannot play a role in improving the hard water resistance and leaf adhesion ability of the water-dispersible granules, resulting in poor dispersion and suspension effects of the water-dispersible granules in hard water, affecting the dispersion and utilization of thiamethoxam and chlorflucythrin in the water-dispersible granules. In addition, since there is a layer of wax on the surface of many plant leaves, this layer of wax is hydrophobic and will repel water-based solutions, making it difficult for the water-dispersible granules to adhere to the plant surface after water-soluble dispersion, and they are easily washed away by rainwater, thereby affecting the insecticidal control effect of thiamethoxam and chlorflucythrin.

[0004] Therefore, combined with the research on the combined toxicity and rapid onset of action of thiamethoxam and chlorfenapyr, a water-dispersible granule with good dispersion and suspension effect, excellent hard water resistance and leaf adhesion ability, which can further optimize the insecticide control effect, is developed, which is of great significance for the development and research of new formulations. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a water dispersible granule comprising thiamethoxam and chlorfenapyr and a preparation method thereof.

[0006] A water dispersible granule containing thiamethoxam and cyhalothrin, the water dispersible granule consisting of the following components in percentage by weight:

[0007] Pesticide active ingredient 30-50%, dispersant 1-12%, disintegrant 3-20%, leaf surface adhesive 1-16% and binder 1-4%, with filler making up the rest;

[0008] The active ingredient of the pesticide is obtained by compounding thiamethoxam, cyfluthrin and catechins, wherein the mass ratio of thiamethoxam to cyfluthrin is (2-4): (1-3), and catechins accounts for 3-5% of the total mass of thiamethoxam and cyfluthrin;

[0009] The raw materials for preparing the leaf surface adhesive include: 10 to 20 parts by weight of cardanol-modified hydroxyethyl cellulose, 80 to 120 parts by weight of dimethyl sulfoxide, 5 to 16 parts by weight of L-ascorbyl palmitate, 60 to 150 parts by weight of 70% ethanol solution and 2 to 8 parts by weight of initiator;

[0010] The raw materials for preparing cardanol-modified hydroxyethyl cellulose include: activated hydroxyethyl cellulose, cardanol, dimethyl sulfoxide and p-toluenesulfonic acid, wherein the mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is (5-15): (1-9): (100-200), the amount of p-toluenesulfonic acid added is 1-6% of the total mass of the activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide, and the activated hydroxyethyl cellulose is obtained by alkalizing hydroxyethyl cellulose with a sodium hydroxide solution.

[0011] A method for preparing water dispersible granules containing thiamethoxam and cyhalothrin, comprising the following steps:

[0012] S1: Preparation of cardanol-modified hydroxyethyl cellulose, mixing hydroxyethyl cellulose activated by alkali treatment, cardanol, p-toluenesulfonic acid and dimethyl sulfoxide, heating and continuously stirring for reaction, and after the reaction is completed, performing reduced pressure distillation, washing and drying to obtain cardanol-modified hydroxyethyl cellulose;

[0013] S2: Preparation of leaf adhesive, mixing cardanol-modified hydroxyethyl cellulose with dimethyl sulfoxide to obtain a cardanol-modified hydroxyethyl cellulose solution, mixing L-ascorbyl palmitate with an ethanol solution to obtain an L-ascorbyl palmitate solution, stirring and mixing the cardanol-modified hydroxyethyl cellulose solution, the L-ascorbyl palmitate solution and an initiator, heating for reaction, and after the reaction is completed, performing reduced pressure distillation, washing and drying to obtain a leaf adhesive;

[0014] S3: Preparation of water dispersible granules: the pesticide active ingredients obtained by mixing thiamethoxam, chlorflucythrinate and catechins are mixed with a dispersant, a disintegrant, a foliar adhesive, a binder, a filler and water to obtain a mixed solution, and the mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

[0015] Furthermore, step S1: preparation of cardanol-modified hydroxyethyl cellulose specifically comprises the following steps:

[0016] S1.1: Add hydroxyethyl cellulose to a 15% sodium hydroxide solution at a solid-liquid mass ratio of 1:(10-20), and soak at room temperature for 1-3 hours. Then, filter out the hydroxyethyl cellulose, wash with anhydrous ethanol, and vacuum dry to obtain activated hydroxyethyl cellulose.

[0017] S1.2: Add activated hydroxyethyl cellulose and cardanol to dimethyl sulfoxide and stir to mix. The mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is (5-15): (1-9): (100-200). After stirring evenly, a mixed solution is obtained. P-toluenesulfonic acid is added to the mixed solution. The amount of p-toluenesulfonic acid added is 1-6% of the mass of the mixed solution. The mixture is stirred and reacted at 70-110°C for 2-8 hours.

[0018] S1.3: After the reaction is completed, the cardanol-modified hydroxyethyl cellulose is obtained by vacuum distillation, washing and drying.

[0019] Furthermore, step S2: preparation of the leaf surface adhesive specifically comprises the following steps:

[0020] S2.1: adding 10 to 20 parts by weight of cardanol-modified hydroxyethyl cellulose to 80 to 120 parts by weight of dimethyl sulfoxide and stirring evenly to obtain a cardanol-modified hydroxyethyl cellulose solution, adding 5 to 16 parts by weight of L-ascorbyl palmitate to 60 to 150 parts by weight of a 70% ethanol solution and stirring evenly to obtain an L-ascorbyl palmitate solution;

[0021] S2.2: Stir and mix the cardanol-modified hydroxyethyl cellulose solution and the L-ascorbyl palmitate solution obtained above, heat to 50-80° C., add 2-8 parts by weight of an initiator, and stir to react for 4-8 hours;

[0022] S2.3: After the reaction is completed, the foliar adhesive is obtained by vacuum distillation, washing and drying, and passing through a 100-mesh sieve.

[0023] Furthermore, the initiator in step S2.2 is one of potassium persulfate, ammonium persulfate, and hydrogen peroxide.

[0024] Furthermore, step S3: preparation of water dispersible granules specifically comprises the following steps:

[0025] S3.1: Mix thiamethoxam and cyhalothrin in a mass ratio of (2-4):(1-3), add catechin, wherein the catechin accounts for 3-5% of the total mass of thiamethoxam and cyhalothrin, and mix well to obtain a pesticide active ingredient;

[0026] S3.2: The pesticide active ingredient, dispersant, disintegrant, foliar adhesive and binder are mixed, stirred and crushed into powder to obtain a mixed material;

[0027] S3.3: Mix and stir the mixed material, filler and water to obtain a mixed liquid;

[0028] S3.4: The mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

[0029] Furthermore, the dispersant is at least one of sodium lignin sulfonate, calcium lignin sulfonate, and fatty alcohol polyoxyethylene ether.

[0030] Furthermore, the disintegrant is at least one of potassium carbonate, sodium carbonate, ammonium sulfate, sodium bicarbonate, and bentonite.

[0031] Furthermore, the binder is at least one of polyethylene glycol, sucrose, dextrin and xanthan gum.

[0032] Furthermore, the filler is at least one of kaolin, attapulgite, white carbon black, diatomaceous earth and light calcium carbonate.

[0033] The present invention has at least the following advantages:

[0034] 1. In the present invention, the activated hydroxyethyl cellulose is subjected to an esterification reaction with cardanol, and the cardanol-modified hydroxyethyl cellulose has good hard water resistance and wetting and adhesion properties, which is beneficial to adjusting the wetting viscosity, suspension and hard water resistance of the water-dispersible granules, reducing the types of additives used, reducing the splashing during the spraying of the liquid medicine, making the liquid medicine more evenly distributed on the plant surface, increasing the wetting and spreading area of ​​the droplets after spraying, thereby improving the utilization rate of the active ingredients of the pesticide, and the polar groups in the cardanol can not only form hydrogen bonds with water molecules to reduce the surface tension of the liquid medicine, but also form complexes with hard water components in the liquid medicine, such as calcium and magnesium ions, to reduce the influence of hard water on the hydroxyethyl cellulose, ensure the dispersion stability of the hydroxyethyl cellulose in hard water, and further improve the dispersion and suspension effect of the water-dispersible granules in hard water, and prevent the particles in the water-dispersible granules from aggregating and settling.

[0035] 2. In the present invention, cardanol-modified hydroxyethyl cellulose and L-ascorbyl palmitate are grafted and compounded through a free radical polymerization reaction, so that L-ascorbyl palmitate and the free radicals generated by the initiator undergo a growth reaction to form a graft chain, and the formed graft chain can be further grafted and copolymerized with the cardanol-modified hydroxyethyl cellulose molecular chain to obtain a foliar adhesive. The hydrophilic-hydrophobic balance property of L-ascorbyl palmitate in the foliar adhesive can cause the hydrophilic end of L-ascorbyl palmitate to hydrogen bond with the foliar wax layer, and the hydrophobic end of L-ascorbyl palmitate to generate a hydrophobic force with the foliar wax layer. Through the combination of the two forces, the water-dispersible granules have strong adhesion and high retention rate, so that the active ingredients of the pesticide are better adhered to the plant surface, and the loss caused by rain erosion is reduced.

[0036] 3. In the present invention, thiamethoxam, chlorflucythrinate and catechins are compounded so that the catechins in the active ingredients of the pesticide account for 3-5% of the total mass of thiamethoxam and chlorflucythrinate. Thiamethoxam can interfere with the transmission of neurotransmitters, while high-efficiency chlorflucythrinate can affect the respiratory system of pests, and catechins can destroy the cell membranes of pests. The combined use of the three can achieve a better synergistic effect through multiple mechanisms such as complementary action mechanisms, physiological and biochemical synergy, and enhanced environmental adaptability, thereby interfering with the physiological functions of pests in multiple directions, effectively enhancing the control effect, and prolonging the overall control duration. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The flowchart is a method for preparing water dispersible granules containing thiamethoxam and chlorfenapyr in an embodiment of the present invention.

[0038] Figure 2 The figure is a comparison chart of the suspension rate test results of the water dispersible granules of the embodiments of the present invention and some comparative examples. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] A method for preparing water dispersible granules containing thiamethoxam and chlorfenapyr, such as Figure 1 As shown, the specific steps include:

[0042] S1: Preparation of cardanol-modified hydroxyethyl cellulose,

[0043] S1.1: Add hydroxyethyl cellulose to a 15% sodium hydroxide solution at a solid-liquid mass ratio of 1:20, and soak at room temperature for 3 hours. Then, filter out the hydroxyethyl cellulose, wash with anhydrous ethanol, and vacuum dry to obtain activated hydroxyethyl cellulose.

[0044] S1.2: Add activated hydroxyethyl cellulose and cardanol to dimethyl sulfoxide and stir to mix. The mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is 10:9:200. After stirring evenly, a mixed solution is obtained. P-toluenesulfonic acid is added to the mixed solution. The amount of p-toluenesulfonic acid added is 6% of the mass of the mixed solution. Stir and react at 100°C for 6 hours.

[0045] S1.3: After the reaction is completed, the cardanol-modified hydroxyethyl cellulose is obtained by vacuum distillation, washing and drying;

[0046] S2: Preparation of leaf adhesive,

[0047] S2.1: 20 parts by weight of cardanol-modified hydroxyethyl cellulose are added to 120 parts by weight of dimethyl sulfoxide and stirred to obtain a cardanol-modified hydroxyethyl cellulose solution; 16 parts by weight of L-ascorbyl palmitate are added to 150 parts by weight of a 70% ethanol solution and stirred to obtain an L-ascorbyl palmitate solution;

[0048] S2.2: The cardanol-modified hydroxyethyl cellulose solution and the L-ascorbyl palmitate solution obtained above were stirred and mixed, heated to 80° C., 8 parts by weight of hydrogen peroxide were added, and stirred to react for 8 hours;

[0049] S2.3: After the reaction is completed, the leaf surface adhesive is obtained by vacuum distillation, washing and drying, and passing through a 100-mesh sieve;

[0050] S3: Preparation of water dispersible granules,

[0051] S3.1: Mix thiamethoxam and cyhalothrin in a mass ratio of 4:3, add catechin, wherein the catechin accounts for 5% of the total mass of thiamethoxam and cyhalothrin, and mix well to obtain a pesticide active ingredient;

[0052] S3.2: 38 parts by weight of the active ingredient of the pesticide, 8 parts by weight of sodium lignin sulfonate, 16 parts by weight of bentonite, 10 parts by weight of a foliar adhesive and 2 parts by weight of polyethylene glycol are mixed, stirred and crushed into powder to obtain a mixed material;

[0053] S3.3: The above-obtained mixed material, 20 parts by weight of attapulgite and 100 parts by weight of water are mixed and stirred to obtain a mixed solution;

[0054] S3.4: The mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

[0055] Example 2

[0056] A method for preparing water dispersible granules containing thiamethoxam and chlorfenapyr, such as Figure 1 As shown, the specific steps include:

[0057] S1: Preparation of cardanol-modified hydroxyethyl cellulose,

[0058] S1.1: Add hydroxyethyl cellulose to a 15% sodium hydroxide solution at a solid-liquid mass ratio of 1:20, and soak at room temperature for 1 hour. Then, filter out the hydroxyethyl cellulose, wash with anhydrous ethanol, and vacuum dry to obtain activated hydroxyethyl cellulose.

[0059] S1.2: Add activated hydroxyethyl cellulose and cardanol to dimethyl sulfoxide and stir to mix. The mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is 10:9:200. After stirring evenly, a mixed solution is obtained. P-toluenesulfonic acid is added to the mixed solution. The amount of p-toluenesulfonic acid added is 6% of the mass of the mixed solution. Stir and react at 70°C for 8 hours.

[0060] S1.3: After the reaction is completed, the cardanol-modified hydroxyethyl cellulose is obtained by vacuum distillation, washing and drying;

[0061] S2: Preparation of leaf adhesive,

[0062] S2.1: 20 parts by weight of cardanol-modified hydroxyethyl cellulose are added to 120 parts by weight of dimethyl sulfoxide and stirred to obtain a cardanol-modified hydroxyethyl cellulose solution; 16 parts by weight of L-ascorbyl palmitate are added to 150 parts by weight of a 70% ethanol solution and stirred to obtain an L-ascorbyl palmitate solution;

[0063] S2.2: The cardanol-modified hydroxyethyl cellulose solution and the L-ascorbyl palmitate solution obtained above were stirred and mixed, heated to 60° C., 8 parts by weight of hydrogen peroxide were added, and stirred to react for 8 hours;

[0064] S2.3: After the reaction is completed, the leaf surface adhesive is obtained by vacuum distillation, washing and drying, and passing through a 100-mesh sieve;

[0065] S3: Preparation of water dispersible granules,

[0066] S3.1: Mix thiamethoxam and cyhalothrin in a mass ratio of 4:3, add catechin, wherein the catechin accounts for 5% of the total mass of thiamethoxam and cyhalothrin, and mix well to obtain a pesticide active ingredient;

[0067] S3.2: 38 parts by weight of the active ingredient of the pesticide, 8 parts by weight of sodium lignin sulfonate, 16 parts by weight of bentonite, 10 parts by weight of a foliar adhesive and 2 parts by weight of polyethylene glycol are mixed, stirred and crushed into powder to obtain a mixed material;

[0068] S3.3: The above-obtained mixed material, 20 parts by weight of attapulgite and 100 parts by weight of water are mixed and stirred to obtain a mixed solution;

[0069] S3.4: The mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

[0070] Example 3

[0071] A method for preparing water dispersible granules containing thiamethoxam and chlorfenapyr, such as Figure 1 As shown, the specific steps include:

[0072] S1: Preparation of cardanol-modified hydroxyethyl cellulose,

[0073] S1.1: Add hydroxyethyl cellulose to a 15% sodium hydroxide solution at a solid-liquid mass ratio of 1:10, and soak at room temperature for 3 hours. Then, filter out the hydroxyethyl cellulose, wash with anhydrous ethanol, and vacuum dry to obtain activated hydroxyethyl cellulose.

[0074] S1.2: Add activated hydroxyethyl cellulose and cardanol to dimethyl sulfoxide and stir to mix. The mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is 5:2:100. After stirring evenly, a mixed solution is obtained. P-toluenesulfonic acid is added to the mixed solution. The amount of p-toluenesulfonic acid added is 3% of the mass of the mixed solution. Stir and react at 100°C for 6 hours.

[0075] S1.3: After the reaction is completed, the cardanol-modified hydroxyethyl cellulose is obtained by vacuum distillation, washing and drying;

[0076] S2: Preparation of leaf adhesive,

[0077] S2.1: 10 parts by weight of cardanol-modified hydroxyethyl cellulose are added to 80 parts by weight of dimethyl sulfoxide and stirred to obtain a cardanol-modified hydroxyethyl cellulose solution; 5 parts by weight of L-ascorbyl palmitate are added to 60 parts by weight of a 70% ethanol solution and stirred to obtain an L-ascorbyl palmitate solution;

[0078] S2.2: The cardanol-modified hydroxyethyl cellulose solution and the L-ascorbyl palmitate solution obtained above were stirred and mixed, heated to 80° C., 3 parts by weight of hydrogen peroxide were added, and stirred to react for 8 hours;

[0079] S2.3: After the reaction is completed, the leaf surface adhesive is obtained by vacuum distillation, washing and drying, and passing through a 100-mesh sieve;

[0080] S3: Preparation of water dispersible granules,

[0081] S3.1: Mix thiamethoxam and cyhalothrin in a mass ratio of 2:1, add catechin, wherein the catechin accounts for 3% of the total mass of thiamethoxam and cyhalothrin, and mix well to obtain a pesticide active ingredient;

[0082] S3.2: 38 parts by weight of the active ingredient of the pesticide, 8 parts by weight of sodium lignin sulfonate, 16 parts by weight of bentonite, 10 parts by weight of a foliar adhesive and 2 parts by weight of polyethylene glycol are mixed, stirred and crushed into powder to obtain a mixed material;

[0083] S3.3: The above-obtained mixed material, 20 parts by weight of attapulgite and 100 parts by weight of water are mixed and stirred to obtain a mixed solution;

[0084] S3.4: The mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

[0085] Comparative Example 1

[0086] Compared with Example 1, the difference of Comparative Example 1 is that the cardanol-modified hydroxyethyl cellulose in step S2.1 is replaced by hydroxyethyl cellulose that has not been treated in any way, and the other steps remain unchanged to prepare water dispersible granules, which is recorded as Comparative Example 1.

[0087] Comparative Example 2

[0088] Compared with Example 1, the difference of Comparative Example 2 is that step S2 is removed, the foliar adhesive in step S3.2 is replaced by the cardanol-modified hydroxyethyl cellulose obtained in step S1.3, and the other steps remain unchanged to prepare water-dispersible granules, which is recorded as Comparative Example 2.

[0089] Suspension performance test

[0090] The water dispersible granules prepared in Examples 1-3 and Comparative Examples 1-2 were tested for suspension and hard water resistance. Suspension rate test: According to the test method in GB / T14825-2006 "Determination of suspension rate of pesticides", the suspension rate results were obtained, such as Figure 2 Hard water resistance test: According to the test method in GB / T14825-2006 "Test method for suspension rate of pesticides", the standard hard water is replaced with hard water with ten times the standard concentration, and the hard water suspension rate result is tested, as shown in the figure below. Figure 2 shown.

[0091] like Figure 2It can be seen that the water-dispersible granules in Examples 1-3 have better suspension rate and hard water suspension rate than the water-dispersible granules in Comparative Examples 1-2, have good dispersion and suspension performance and hard water resistance, and effectively reduce the aggregation and sedimentation of the components in the water-dispersible granules. This shows that the cardanol-modified hydroxyethyl cellulose in the foliar adhesive can significantly improve the suspension and hard water resistance of the water-dispersible granules, and the cardanol-modified hydroxyethyl cellulose in the foliar adhesive cooperates with L-ascorbyl palmitate to obtain water-dispersible granules with high suspension rate and strong hard water resistance.

[0092] Determination of leaf contact angle and leaf retention rate

[0093] Leaf contact angle: Select fresh cucumber leaves grown indoors, and wash the cucumber leaves with deionized water to remove dust from the leaf surface and ensure that the leaf surface is not damaged. After the washed leaves are dried at room temperature, they are cut into small leaves with a side length of 1.5 cm. Five small leaves are taken, and the leaf surfaces of the five small leaves are fixed on a glass slide respectively. The water-dispersible granules in Examples 1-3 and Comparative Examples 1-2 are respectively formulated into test solutions with a concentration of 2 mg / L. 2 μL of each test solution is taken and dripped onto the five small leaves respectively. Then, each small leaf together with the glass slide is placed on the stage of the contact angle measuring instrument in sequence, and each droplet image is obtained, and the corresponding contact angle value is calculated to obtain the contact angle result, as shown in Table 1.

[0094] Leaf retention rate: Select fresh cucumber leaves grown indoors and wash them with deionized water to remove dust from the leaf surface and ensure that the leaf surface is not damaged. After the washed leaves are dried at room temperature, 5 leaves are taken as test objects, and the water-dispersible granules in Examples 1-3 and Comparative Examples 1-2 are respectively formulated into test solutions with a concentration of 2 mg / L, and each test solution is evenly sprayed on the surface of 5 different leaves with a spray gun. Each leaf after spraying is divided into two parts along the main veins, one part of which is pressurized with 100 mL of deionized water to simulate rainfall and wash the leaves, and the other part is not washed. After the droplets on the surface of the leaves were dried, the two parts of each leaf were cut into pieces with scissors, and the content of pesticide active ingredients in the two parts of each leaf was detected by high performance liquid chromatography (the pesticide active ingredients included catechins, thiamethoxam and chlorfenapyr), and the leaf surface retention rate of the pesticide active ingredients was calculated. The calculation formula of the leaf surface retention rate was: leaf surface retention rate (%) = (pesticide active ingredient content of unwashed leaves-pesticide active ingredient content of washed leaves) / pesticide active ingredient content of unwashed leaves*100%, and the leaf surface retention rate results were obtained, as shown in Table 1.

[0095] Table 1

[0096]

[0097] As shown in Table 1, after the water-dispersible granules in Examples 1-3 are sprayed onto the surface of cucumber leaves, the leaf contact angle of the droplets is significantly smaller than that of the water-dispersible granules in Comparative Examples 1-2, indicating that the cardanol-modified hydroxyethyl cellulose and L-ascorbyl palmitate in the leaf adhesive can both improve the wetting effect of the water-dispersible granules on the surface of cucumber leaves after spraying, and reduce the surface tension after spraying and wetting, among which the wetting effect of L-ascorbyl palmitate is the most significant; and, after the water-dispersible granules in Examples 1-3 are subjected to simulated rainfall pressure washing, the leaf retention rate of the pesticide active ingredients in the water-dispersible granules can be maintained at more than 69%, showing good adhesion performance, effectively reducing the loss caused by rain erosion.

[0098] Comparative Example 3

[0099] Compared with Example 1, the difference of Comparative Example 3 is that in step S3.1, the pesticide active ingredient is prepared by mixing thiamethoxam and chlorfenapyr in a mass ratio of 4:3, catechin is not added to the pesticide active ingredient, and the other steps remain unchanged to prepare water dispersible granules, which is recorded as Comparative Example 3.

[0100] Comparative Example 4

[0101] Compared with Example 1, the difference of Comparative Example 4 is that, in the pesticide active ingredient of step S3.1, catechin accounts for 1% of the total mass of thiamethoxam and chlorfenapyr, and the other steps remain unchanged to prepare water dispersible granules, which is recorded as Comparative Example 4.

[0102] Comparative Example 5

[0103] Compared with Example 1, the difference of Comparative Example 5 is that, among the pesticide active ingredients in step S3.1, catechin accounts for 6% of the total mass of thiamethoxam and chlorfenapyr, and the other steps remain unchanged. The water dispersible granules are prepared, which is recorded as Comparative Example 5.

[0104] Effectiveness test

[0105] Cabbage seedlings were cultured in a greenhouse, and 6 cabbage seedlings with similar growth conditions and 3 true leaves were selected as test objects. The water dispersible granules prepared in Examples 1-3 and Comparative Examples 3-5 were respectively added with water to prepare spray test solutions with a concentration of 0.5 g / L, and the above groups of spray test solutions were respectively sprayed on the front and back sides of the leaves of 6 different test objects using a manual sprayer. Each test object was placed in an insect box and cultured at 25° C. for 10 days using a plant growth regulating lamp. 50 aphids were inoculated on all leaves of each test object on the 1st, 3rd and 7th days during the culture process. The number of aphid deaths on each leaf of each test object and the growth of each test object were checked on the 2nd, 5th and 10th days during the culture process, and the corresponding aphid mortality rate on each leaf of each test object was calculated. The calculation formula for the corresponding aphid mortality rate of each leaf is: the corresponding aphid mortality rate of each leaf (%) = (initial base number of aphids - number of residual insects) / initial base number of aphids * 100%, and then the aphid mortality rate of each test object is calculated by the corresponding aphid mortality rate of each leaf. The aphid mortality rate and growth results are shown in Table 2.

[0106] Table 2:

[0107]

[0108] As shown in Table 2, after the control effect test, the aphid mortality rate of the cabbage seedling test objects sprayed with the water dispersible granules of Examples 1-3 within 10 days can be maintained at a level of more than 98%, which can effectively control aphids, and the cabbage seedling test objects can maintain a normal growth state; the aphid control ability of the cabbage seedling test objects sprayed with the water dispersible granules of Comparative Example 3 gradually weakened within 10 days, and slight spots and honeydew appeared on the leaves of the cabbage seedling test objects, indicating that the addition of catechins to the pesticide active ingredients of the water dispersible granules can enhance the control effect, so that The catechins, thiamethoxam and chlorfenapyr play a synergistic role with each other; the cabbage seedling test object sprayed with the water dispersible granules of comparative example 4, although it can maintain a normal growth state and reach a 90% aphid mortality rate, the control effect is gradually weaker than that of Examples 1-3 after the fifth day; the cabbage seedling test object sprayed with the water dispersible granules of comparative example 5, although it can maintain a aphid mortality rate of more than 97%, the leaves of the cabbage seedling test object turn yellow and have spots, indicating that the catechin content in the pesticide active ingredient of the water dispersible granules exceeds the applicable range, which has a negative impact on the plant itself.

[0109] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention. Parts not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A water dispersible granule comprising thiamethoxam and cyhalothrin, characterized in that: The water dispersible granules are composed of the following components in percentage by weight: The active ingredient of pesticide is 30-50%, dispersant is 1-12%, disintegrant is 3-20%, leaf adhesive is 1-16% and binder is 1-4%, and filler makes up the rest; The active ingredient of the pesticide is obtained by compounding thiamethoxam, cyfluthrin and catechins, wherein the mass ratio of thiamethoxam to cyfluthrin is (2-4): (1-3), and catechins accounts for 3-5% of the total mass of thiamethoxam and cyfluthrin; The raw materials for preparing the leaf surface adhesive include: 10 to 20 parts by weight of cardanol-modified hydroxyethyl cellulose, 80 to 120 parts by weight of dimethyl sulfoxide, 5 to 16 parts by weight of L-ascorbyl palmitate, 60 to 150 parts by weight of 70% ethanol solution and 2 to 8 parts by weight of initiator; The raw materials for preparing cardanol-modified hydroxyethyl cellulose include: activated hydroxyethyl cellulose, cardanol, dimethyl sulfoxide and p-toluenesulfonic acid, wherein the mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is (5-15): (1-9): (100-200), the amount of p-toluenesulfonic acid added is 1-6% of the total mass of the activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide, and the activated hydroxyethyl cellulose is obtained by alkalizing hydroxyethyl cellulose with a sodium hydroxide solution.

2. A method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 1, characterized in that: The specific steps are as follows: S1: Preparation of cardanol-modified hydroxyethyl cellulose, mixing hydroxyethyl cellulose activated by alkali treatment, cardanol, p-toluenesulfonic acid and dimethyl sulfoxide, heating and continuously stirring for reaction, and after the reaction is completed, performing reduced pressure distillation, washing and drying to obtain cardanol-modified hydroxyethyl cellulose; S2: Preparation of leaf adhesive, mixing cardanol-modified hydroxyethyl cellulose with dimethyl sulfoxide to obtain a cardanol-modified hydroxyethyl cellulose solution, mixing L-ascorbyl palmitate with an ethanol solution to obtain an L-ascorbyl palmitate solution, stirring and mixing the cardanol-modified hydroxyethyl cellulose solution, the L-ascorbyl palmitate solution and an initiator, heating for reaction, and after the reaction is completed, performing reduced pressure distillation, washing and drying to obtain a leaf adhesive; S3: Preparation of water dispersible granules: the pesticide active ingredients obtained by mixing thiamethoxam, chlorflucythrinate and catechins are mixed with a dispersant, a disintegrant, a foliar adhesive, a binder, a filler and water to obtain a mixed solution, and the mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

3. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 2, characterized in that: Step S1: Preparation of cardanol-modified hydroxyethyl cellulose, specifically comprising the following steps: S1.1: Add hydroxyethyl cellulose to a 15% sodium hydroxide solution at a solid-liquid mass ratio of 1:(10-20), and soak at room temperature for 1-3 hours. Then, filter out the hydroxyethyl cellulose, wash with anhydrous ethanol, and vacuum dry to obtain activated hydroxyethyl cellulose. S1.2: Add activated hydroxyethyl cellulose and cardanol to dimethyl sulfoxide and stir to mix. The mass ratio of activated hydroxyethyl cellulose, cardanol and dimethyl sulfoxide is (5-15): (1-9): (100-200). After stirring evenly, a mixed solution is obtained. P-toluenesulfonic acid is added to the mixed solution. The amount of p-toluenesulfonic acid added is 1-6% of the mass of the mixed solution. The mixture is stirred and reacted at 70-110°C for 2-8 hours. S1.3: After the reaction is completed, the cardanol-modified hydroxyethyl cellulose is obtained by vacuum distillation, washing and drying.

4. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 3, characterized in that: Step S2: Preparation of leaf surface adhesive, specifically comprising the following steps: S2.1: adding 10 to 20 parts by weight of cardanol-modified hydroxyethyl cellulose to 80 to 120 parts by weight of dimethyl sulfoxide and stirring evenly to obtain a cardanol-modified hydroxyethyl cellulose solution, adding 5 to 16 parts by weight of L-ascorbyl palmitate to 60 to 150 parts by weight of a 70% ethanol solution and stirring evenly to obtain an L-ascorbyl palmitate solution; S2.2: Stir and mix the cardanol-modified hydroxyethyl cellulose solution and the L-ascorbyl palmitate solution obtained above, heat to 50-80° C., add 2-8 parts by weight of an initiator, and stir to react for 4-8 hours; S2.3: After the reaction is completed, the foliar adhesive is obtained by vacuum distillation, washing and drying, and passing through a 100-mesh sieve.

5. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 4, characterized in that: The initiator in step S2.2 is one of potassium persulfate, ammonium persulfate and hydrogen peroxide.

6. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 4, characterized in that: Step S3: Preparation of water dispersible granules, specifically comprising the following steps: S3.1: Mix thiamethoxam and cyhalothrin in a mass ratio of (2-4):(1-3), add catechin, wherein the catechin accounts for 3-5% of the total mass of thiamethoxam and cyhalothrin, and mix well to obtain a pesticide active ingredient; S3.2: The pesticide active ingredient, dispersant, disintegrant, foliar adhesive and binder are mixed, stirred and crushed into powder to obtain a mixed material; S3.3: Mix and stir the mixed material, filler and water to obtain a mixed liquid; S3.4: The mixed solution is subjected to negative pressure spray drying and granulation to obtain water dispersible granules.

7. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 6, characterized in that: The dispersant is at least one of sodium lignin sulfonate, calcium lignin sulfonate and fatty alcohol polyoxyethylene ether.

8. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 7, characterized in that: The disintegrant is at least one of potassium carbonate, sodium carbonate, ammonium sulfate, sodium bicarbonate and bentonite.

9. The method for preparing the water dispersible granules containing thiamethoxam and chlorfenapyr according to claim 8, characterized in that: The binder is at least one of polyethylene glycol, sucrose, dextrin and xanthan gum.

10. The method for preparing the water dispersible granules containing thiamethoxam and cyhalothrin according to claim 9, characterized in that: The filler is at least one of kaolin, attapulgite, white carbon black, diatomaceous earth and light calcium carbonate.

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