A suspension agent containing boscalid and pyraclostrobin

Abstract

The present invention relates to a suspension agent containing bixafen and pyraclostrobin. By weight percentage, the raw material ratio is as follows: bixafen 10%, pyraclostrobin 10%, wetting agent 3%, dispersant 5%, thickening agent 1.2%, defoaming agent 0.1%, antifreeze agent 4%, and the balance is deionized water. The present invention takes Rhizoctonia solani as the object, and through the indoor toxicity determination of the compounding of bixafen and pyraclostrobin in different mass ratios, the optimal ratio is determined. After comprehensively considering the drug cost, field control effect and delaying the drug resistance of pathogens, the development of 20% bixafen·pyraclostrobin suspension agent is determined. After screening the types and quantities of related auxiliaries of the suspension agent, the optimal ratio of the suspension agent is determined. At the same time, the related physical and chemical properties of the suspension agent are measured to test whether the preparation meets the relevant standards of the suspension agent. And after the determination of the related physical and chemical properties, it is applied to the prevention and control of rice sheath blight in the field.

Description

Technical Field

[0001] The present invention relates to a suspension agent containing bixafen and pyraclostrobin, which is used for controlling sheath blight of rice and belongs to the technical field of pesticides. Background Art

[0002] Bixafen is a pyrazole carboxamide fungicide developed by Bayer CropScience. Bixafen is a systemic fungicide with a broad fungicidal spectrum, having both preventive and therapeutic effects, and can inhibit spore germination, mycelial growth and spore formation. Some studies have shown that when using bixafen to control sheath blight of wheat, it can delay crop senescence and increase yield. It is generally specifically used for foliar spraying to control important diseases caused by ascomycetes, basidiomycetes and deuteromycetes, and is widely used in crops such as cereals (including barley, wheat, oats, rye, triticale, etc.), grapes, corn, potatoes, cotton, sunflowers, soybeans, other legumes (such as chickpeas, purple-flowered peas, lentils, etc.), rapeseed, sugar beets, peanuts, etc., as well as non-crop fields.

[0003] Like other SDHI fungicides, bixafen has a relatively high risk of drug resistance due to its single site of action. For this reason, many compound products of bixafen have been developed by companies such as Bayer and FMC. The active ingredients participating in the compounding include: prothioconazole, tebuconazole, fluopyram, trifloxystrobin, flutriafol, azoxystrobin, iprodione, prothioconazole + tebuconazole, prothioconazole + spiroxamine, prothioconazole + fluoxastrobin, prothioconazole + trifloxystrobin, prothioconazole + fluopyram, etc.

[0004] Its chemical name: N-(3′,4′-dichloro-5-fluorobiphenyl-2-yl)-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide, and its molecular structural formula is as follows:

[0005]

[0006] Pyraclostrobin, as a new broad-spectrum acrylate fungicide developed by BASF, is improved on the basis of kresoxim-methyl and has a pyrazole structure. It inhibits the respiration of cell mitochondria and blocks the electron transfer in the process of cytochrome synthesis, thereby causing cell death. Pyraclostrobin has high fungicidal activity, which is 3 times that of similar fungicides. When it is sprayed on the leaf surface of plants, it can be quickly decomposed and dissipated. The active ingredient that penetrates into the parenchyma tissue of plants can exist in the tissue for a long time and has a conduction effect, and has a long residual effect on fungi. Currently, it is mainly used to control ascomycetes, basidiomycetes, asexual fungi and oomycete diseases of crops such as wheat, rice and vegetables. At the same time, pyraclostrobin has the effects of promoting plant growth, delaying plant senescence and improving the stress resistance of plants. Its chemical name: N-[2-[[1-(4-chlorophenyl)pyrazol-3-yl]oxymethyl]phenyl]-N-methoxycarbamate, and its molecular structural formula is as follows:

[0007]

[0008] The application of chemical agents is the most effective means of preventing and controlling plant diseases and insect pests. However, the long-term continuous high-dose application of a single chemical agent is likely to cause problems such as agent residues, environmental pollution, and the development of drug-resistant populations. Reasonable compounding or mixing of chemical fungicides has the positive characteristics of expanding the antibacterial spectrum, improving the prevention and control effect, extending the appropriate period of application, reducing the amount of medicine used, reducing the key points, reducing residues, and delaying the occurrence and development of pathogen resistance and drug resistance. Fungicide compounding is one of the most effective ways to solve the above problems. The price of developing new fungicides continues to rise. In contrast, the development and research of high-efficiency, low-toxicity, and low-residue compounds and mixtures have low investment and short development cycle, and have attracted attention at home and abroad, and have increased their development efforts.

[0009] In order to prevent the high resistance of pathogens caused by long-term and large-scale use of the above-mentioned single agent, the inventors conducted in-depth research on bixafen and pyraclostrobin, and found that the two agents have high synergistic activity when compounded within a certain ratio range, which can be well controlled. After the two agents are mixed and used, it is also beneficial to reduce the amount of the agents used, reduce the number of spraying, and delay the generation of drug resistance. At present, bixafen and its compound preparation with pyraclostrobin have not been applied to the prevention and control of rice sheath blight. Summary of the invention

[0010] The purpose of the present invention is to provide a suspension containing bixafen and pyraclostrobin, which can be used to prevent and treat rice sheath blight. Compared with the efficacy of a single agent, the two agents have a good synergistic effect after being combined.

[0011] The object of the present invention is achieved in that a suspension containing bixafen and pyraclostrobin is prepared, wherein the raw material ratio is as follows, by weight percentage: 10% of bixafen, 10% of pyraclostrobin, 3% of a wetting agent, 5% of a dispersant, 1.2% of a thickener, 0.1% of a defoaming agent, 4% of an antifreeze agent, and the balance is deionized water.

[0012] The wetting agent described in the present invention is Morwet EFW, which is a mixture of alkylnaphthalene sulfonate and anionic wetting agent, with an active ingredient greater than 95%. It is the product with the best wettability and permeability in the Morwet series, and its characteristics are that it can quickly wet and help disintegrate particles. The strong wettability of this product makes it very easy to absorb moisture in the air, and it needs to be sealed and stored in a dry place. The wetting agent Morwet EFW is suitable for WP and SC.

[0013] The dispersant A755 described above is a comb-shaped polymer stabilizing dispersant, which can simultaneously have the effects of a stabilizer and a dispersant, and has excellent dispersibility for SE and SC formulations.

[0014] The thickener described above is composed of xanthan gum and magnesium aluminum silicate. Xanthan gum accounts for 17% of the weight of the thickener, and magnesium aluminum silicate accounts for 83% of the weight of the thickener. It has the characteristics of high viscosity at low concentration and is an efficient thickener.

[0015] The defoamer described above is SAG1572, which is a durable silicone antifoaming agent with a fast defoaming speed. It has an excellent persistent foam control function. Generally, the use concentration is lower than that of most traditional defoamers. Another advantage is that it can be evenly dispersed in aqueous formulations and concentrates, thereby improving the storage stability of the mixture. The SAG1572 defoamer also has the characteristic of a wide pH adaptability and is an ideal choice for defoamers in the production, packaging, and spray tank applications of pesticides.

[0016] The antifreeze described above is ethylene glycol, which can prevent problems such as flocculation, caking, and severe stratification of the product.

[0017] The method of the present invention is advanced and scientific. The inventor found in long-term experimental studies that when the mass ratio of bixafen to pyraclostrobin in the present invention is 3:1 to 1:3, obvious synergistic effects can be achieved; preferably, the mass ratio of bixafen to pyraclostrobin is 1:2. Considering the drug cost and synergistic effect, bixafen has not been used as a single agent or compound agent for the control of sheath blight of rice. By increasing the amount of bixafen used, the resistance of pathogens to pyraclostrobin can be delayed. Therefore, the mass ratio of bixafen to pyraclostrobin is more preferably 1:1.

[0018] The bixafen described in the present invention uses 95% bixafen technical and 98% pyraclostrobin technical.

[0019] The present invention uses the existing suspension preparation process to prepare a suspension containing bixafen and pyraclostrobin. The specific preparation steps are as follows: First, mix the wetting agent, dispersant, thickener, defoamer, antifreeze, and stabilizer in proportion. After high-speed shearing and dispersion, add the bixafen and pyraclostrobin technical in proportion, and add grinding zirconium beads for ultrafine grinding and milling for 2.5 h. Finally, add deionized water for secondary mixing and stirring, and filter to obtain the product, that is, the bixafen·pyraclostrobin composition suspension. The particle size of the bixafen·pyraclostrobin composition suspension described in the present invention is less than 5 μm.

[0020] During the preparation process, the user can adjust the addition amount of grinding zirconium beads according to the specific situation of the preparation. Generally, adding 100 g is sufficient, which can promote the uniform grinding of the mixture and finer particle size. After grinding, it can be reused after filtration and cleaning.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The usage range of bixafen and pyraclostrobin single agents is expanded. After compounding, it can effectively control sheath blight of rice and delay the generation of resistance to a single pesticide.

[0023] (2) Bixafen is a systemic fungicide with a broad bactericidal spectrum, having both preventive and therapeutic effects. It can inhibit spore germination, mycelial growth and spore formation. It can delay crop senescence and increase crop yield. Moreover, pyraclostrobin has systemic activity, high bactericidal activity, and the active ingredient infiltrating into plant parenchyma can exist in the tissue for a long time and has a conduction effect, showing long residual efficacy against fungi. At the same time, pyraclostrobin can promote plant growth, delay plant senescence and improve the stress resistance of plants. The binary compounding of two agents with different action sites can complement each other's advantages, effectively delay the resistance problem caused by the use of a single agent, extend the service life of the agent, and is of great significance for the comprehensive control of sheath blight of rice.

[0024] (3) The formulation is simple. After the auxiliary agent is dispersed by high-speed shearing of a shearing machine, the original drug and zirconium beads are added for grinding, and finally deionized water is added and stirred evenly after mixing, which can ensure the particle size of the microparticles is uniform to the greatest extent, with good physical and chemical properties and meeting the requirements of the preparation.

[0025] The present invention takes Rhizoctonia solani as the object, conducts indoor toxicity determination by compounding bixafen and pyraclostrobin in different mass ratios, and determines the best ratio. After comprehensively considering the drug use cost, field control effect and delaying the resistance of pathogenic bacteria, it is determined to develop a 20% bixafen·pyraclostrobin suspension concentrate. After screening the types and amounts of related auxiliary agents for the suspension concentrate, the best ratio of the suspension concentrate is determined. At the same time, the related physical and chemical properties of the suspension concentrate are measured to test whether the preparation meets the relevant standards of the suspension concentrate. And after the relevant physical and chemical properties are measured, it is applied to the control of sheath blight of rice in the field.

[0026] At present, the control of sheath blight of rice still mainly relies on chemical pesticides, and there is no application of bixafen and its compound agents in the control of sheath blight of rice in the field. The dosage form of this compound agent is a suspension concentrate, with a simple preparation process and good physical and chemical properties, meeting the requirements of preparation production. When applying the 20% bixafen·pyraclostrobin suspension concentrate to control sheath blight of rice in the field, the use of chemical pesticides can be reduced, the control effect on sheath blight of rice can be increased, and the resistance of Rhizoctonia solani of rice can be delayed. At the same time, compared with traditional pesticide dosage forms, the suspension concentrate dosage form is safe to use and can reduce pesticide waste and environmental pollution caused by chemical pesticides. It can reduce the cost of disease control in production and increase the economic benefits of agricultural producers. Specific embodiments

[0027] The present invention will be further described below in conjunction with specific embodiments.

[0028] For indoor toxicity determination, first, through indoor toxicity determination, the formulation of the composition is preliminarily screened, and the mycelial growth rate method is used to determine the toxicity of each single agent and compound agent against Rhizoctonia solani of rice. The EC of each agent is calculated by the Wadley method. 50 value. The inhibition rate is calculated by formula (1).

[0029]

[0030] In the formula, I represents the colony growth inhibition rate; Dc represents the diameter of the control colony; Dt represents the diameter of the treated colony.

[0031] According to the size of the EC of the single agent 50 value, boscalid and pyraclostrobin are compounded at ratios of 3:1, 2:1, 1:1, 1:2, and 1:3. The agents with each ratio are formulated into culture media containing drugs with gradient concentrations of 0.0125, 0.05, 0.25, 1, 5, and 10 μg / mL, and the EC of each compound agent against Rhizoctonia solani of rice is measured. 50 value, and the theoretical EC of the agents with each ratio is calculated according to the EC of each single agent by formula (2). 50 value. The synergistic coefficient is calculated by formula (3). When SR > 1.5, it is a synergistic effect; when 0.5 ≤ SR ≤ 1.5, it is an additive effect; when SR < 0.5, it is an antagonistic effect. 50 value.

[0032]

[0033]

[0034] A: Boscalid; B: Pyraclostrobin; a: The proportion of boscalid in the compound agent; b: The proportion of pyraclostrobin in the compound agent; EC(A) 50 and EC(B) 50 : The measured EC of each single agent 50 value; EC 50 (th): The theoretical EC of the compound agent 50 value; EC 50 (ob): The measured EC of the mixed agent 50 value. On this basis, after screening out the composition formulation with the best synergistic effect, the formulation screening of the suspension agent and the determination of the relevant physicochemical properties of the best formulation are carried out.

[0035] Indoor toxicity determination test of the composition of the present invention

[0036] The indoor toxicity determination test includes the toxicity determination of a suspension containing boscalid and pyraclostrobin against Rhizoctonia solani. The test agents used are 95% boscalid technical and 98% pyraclostrobin technical. The test strain is Rhizoctonia solani YN-7 isolated from diseased rice plants with sheath blight in Jiangsu by this laboratory.

[0037] Biological assay implementation: An indoor toxicity determination test of a suspension containing boscalid and pyraclostrobin against Rhizoctonia solani.

[0038] Table 1 Indoor toxicity determination of boscalid, pyraclostrobin and their compound combinations with different ratios against Rhizoctonia solani

[0039] Table 1 Joint toxicity of the compound combination of boscalid and pyraclostrobin against Rhizoctonia solani

[0040]

[0041]

[0042] It can be seen from Table 1 that when boscalid and pyraclostrobin are compounded in the range of 3:1 to 1:3, the co-toxicity coefficient SR values all show synergistic effects, indicating that the indoor toxicity against Rhizoctonia solani of the compounded agents shows synergistic effects. The composition shows significant synergistic effects against Rhizoctonia solani, and when the ratio is 2:1, 1:1, 1:2, the synergistic effects are good.

[0043] In summary, when the mass ratio of boscalid to pyraclostrobin in the present invention is 3:1 to 1:3, obvious synergistic effects can be achieved; preferably, the mass ratio of pyraclostrobin to boscalid is 1:2. At present, there is no single agent or compound agent of boscalid applied to the control of rice sheath blight. By increasing the dosage of boscalid, the resistance of the pathogen to pyraclostrobin can be delayed. At the same time, considering the cost, therefore, it is more preferred that the mass ratio of boscalid to pyraclostrobin is 1:1 to make a mixed preparation under certain conditions and conduct a field efficacy verification test to further evaluate the actual field control effect.

[0044] The following specific implementation manners of the suspension preparation are used to further elaborate on the above content of the present invention in detail, but this should not be understood that the scope of the above subject matter of the present invention is limited to the following examples. All technologies implemented based on the above content of the present invention belong to the scope of the present invention.

[0045] Dosage form preparation examples

[0046] A suspension agent containing boscalid and pyraclostrobin. By weight percentage, the raw material ratio is as follows: boscalid 10%, d-pyraclostrobin 10%, dispersant A755 5%, wetting agent Morwet EFW 3%, thickener 1.2% (the thickener is composed of xanthan gum and magnesium aluminum silicate, xanthan gum accounts for 17% of the weight of the thickener, and magnesium aluminum silicate accounts for 83% of the weight of the thickener), defoaming agent silicone defoaming agent SAG1572 0.1%, antifreeze ethylene glycol 4%, and the balance is deionized water.

[0047] The specific preparation steps are as follows: First, mix 5% of dispersant A755, 3% of wetting agent Morwet EFW, 1.2% of thickener, 0.1% of silicone defoaming agent SAG1572, and 4% of antifreeze ethylene glycol in proportion. After high-speed shearing and dispersion, add the original drugs of boscalid and pyraclostrobin in proportion, and add grinding zirconium beads for ultrafine grinding and milling for 2.5 h. Finally, add deionized water for secondary mixing and stirring, and filter to obtain the product.

[0048] Determination of relevant physicochemical properties of the suspension agent sample

[0049] Detect the active ingredients of each single agent in the suspension agent by liquid chromatography

[0050] The results show that the two active ingredients, boscalid and pyraclostrobin, meet the formulation ratio requirements as shown in Table 2.

[0051] Table 2 Determination of active ingredients of the suspension agent

[0052]

[0053] Determination of physicochemical properties of the suspension agent sample after cold storage

[0054] Table 3 Physicochemical properties of 20% boscalid·pyraclostrobin suspension agent after 7 days of cold storage

[0055]

[0056] To verify the influence of low temperature on the stability of the formulation, store it at 0 ± 2 °C for 7 days. After the sample returns to room temperature, measure its main performance indicators. The results are shown in Table 3. The suspension rate, persistent foaming property, particle size, viscosity, and pourability are relatively stable among different samples, and the measured values are all within the qualified range.

[0057] Determination of physicochemical properties of the suspension agent sample after heat storage

[0058] Table 4 Physicochemical properties of 20% boscalid·pyraclostrobin suspension agent after 14 days of heat storage

[0059]

[0060] To verify the effect of high temperature on the stability of the preparation, it was stored at 54 °C for 14 days. After the sample returned to room temperature, its main performance indicators were measured. The results are shown in Table 4. The suspension rate, persistent foaming property, particle size, viscosity, and pourability were relatively stable among different samples, and the measured values were all within the qualified range.

[0061] Surface tension of 20% bixafen·pyraclostrobin suspension concentrate at different dilution multiples after storage

[0062] Table 5 Surface tension of 20% bixafen·pyraclostrobin suspension concentrate at different dilution multiples after storage

[0063]

[0064]

[0065] After gradient dilution of the 20% bixafen·pyraclostrobin suspension concentrate samples stored at normal temperature and 54 °C for 14 days, their surface tensions were measured. The results are shown in Table 5, which has the same trend as the change in surface tension after storage at 0 °C. The surface tension of the suspension concentrate increased with the increase in dilution multiple, but after the samples were stored at different temperatures, the surface tensions of the liquid medicines at each dilution multiple were all less than that of the clear water control, indicating that the developed preparation has good spreading properties on the plant surface.

[0066] Contact angle of 20% bixafen·pyraclostrobin suspension concentrate on target leaves at different dilution multiples

[0067] Table 6 Contact angle of 20% bixafen·pyraclostrobin suspension concentrate on target leaves at different dilution multiples

[0068]

[0069] The results are shown in Table 6. When the dilution multiple of the sample was 600 times, the leaf surface contact angle was 45.35°; when diluted 800, 1000, and 1200 times, the leaf surface contact angles were 51.68°, 61.68°, and 68.30° respectively, which were significantly greater than that at 600 times dilution. This shows that as the dilution multiple of the medicament increases, the leaf surface contact angle also increases, but the contact angles of all medicament treatments are much smaller than that of clear water, indicating that the medicament has a wetting effect on the leaf surface of the target crop and is more likely to spread.

[0070] Field test example: Field control effect of 20% bixafen·pyraclostrobin suspension concentrate against sheath blight

[0071] Results of the efficacy test of bixafen and pyraclostrobin in controlling rice sheath blight

[0072] Table 7 Field control effect of 20% bixafen·pyraclostrobin suspension concentrate against sheath blight

[0073]

[0074]

[0075] 1, 2, and 3 are 20% bixafen·pyraclostrobin SC at 60, 90, and 120 gai / ha respectively; 4 is 240 g / L thifluzamide SC at 90 gai / ha, 5 is 25% pyraclostrobin SC at 150 gai / ha; 6 is the water control.

[0076] As can be seen from Table 7, 20% bixafen·pyraclostrobin suspension concentrates at 60 gai / ha, 90 gai / ha, and 120 gai / ha all have good control effects on rice sheath blight. The control effects 10 days after the second application can reach 69.23%, 76.59%, and 87.23% respectively; the field control effects of 20% bixafen·pyraclostrobin suspension concentrates at 90 gai / ha and 120 gai / ha are better than that of single-agent pyraclostrobin at 150 gai / ha, and the field control effect of 20% bixafen·pyraclostrobin suspension concentrate at 120 gai / ha is significantly higher than that of single-agent thifluzamide at 90 gai / ha.

[0077] Therefore, based on the indoor toxicity determination and field efficacy verification test of the composition of bixafen and pyraclostrobin against rice sheath blight, it is concluded that the toxicity and control effect of bixafen:pyraclostrobin at a ratio of 1:1 on rice sheath blight are good. This composition can effectively reduce the number of pesticide applications in the field, reduce the risk of resistance generation of rice sheath blight pathogens caused by long-term use of a single agent, and is of great significance for the control of rice sheath blight in the field.

Claims

1. A suspension agent containing boscalid and pyraclostrobin, characterized in that: In terms of weight percentage, the raw material ratio is as follows: 10% of bixafen, 10% of pyraclostrobin, 5% of dispersant, 3% of wetting agent, 1.2% of thickener, 0.1% of defoamer, 4% of antifreeze, and the balance is deionized water; The wetting agent is Morwet EFW; the dispersant is Agrilan 755; the thickener is a combination of xanthan gum and magnesium aluminum silicate; the defoamer is silicone defoamer SAG1572; the antifreeze is ethylene glycol; The thickener is composed of a combination of xanthan gum and magnesium aluminum silicate, where xanthan gum accounts for 17% of the weight of the thickener and magnesium aluminum silicate accounts for 83% of the weight of the thickener.

2. A preparation method of a suspension agent containing bixafen and pyraclostrobin according to claim 1, characterized in that, The specific steps of the preparation method are as follows: S1. Prepare raw materials; in terms of weight percentage, the raw material ratio is as follows: 10% of bixafen, 10% of pyraclostrobin, 5% of dispersant, 3% of wetting agent, 1.2% of thickener, 0.1% of defoamer, 4% of antifreeze, and the balance is deionized water; S2. First, mix the wetting agent, dispersant, thickener, defoamer, and antifreeze prepared in step S1, and after high-speed shearing and dispersion, add bixafen and pyraclostrobin, and add grinding zirconium beads for ultrafine grinding for 2.5 h. Finally, add deionized water for secondary mixing and stirring, and filter to obtain a suspension containing bixafen and pyraclostrobin.

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