A fluxapyroxad·hexaconazole seed treatment suspension concentrate and its application

Abstract

The present invention provides a seed treatment suspension agent, wherein the active ingredients are composed of hexaconazole and fludioxonil, and the mass ratio of hexaconazole to fludioxonil is 3:1 - 1:7. The weight percentage content of the active ingredients is 1 - 10%; it also contains the following excipients in weight percentage: 3 - 18% of a wetting and dispersing agent, 0.5 - 5% of a thickening agent, 1 - 6% of a film-forming agent, 1 - 5% of a warning agent, 1 - 8% of an antifreezing agent, 0.1 - 1.5% of a preservative, and water makes up to 100%. The seed treatment suspension agent provided by the present invention has excellent synergistic effects and formulation properties, can be used for the prevention and control of bakanae disease of rice, reduce the dosage of pesticides, and slow down the generation of drug resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticides, and particularly relates to a fludioxonil · hexaconazole seed treatment suspension agent and its application. Background Art

[0002] Bakanae disease of rice, also known as bakanae disease, is a common and highly harmful disease in rice production areas. It is mainly transmitted through seed-borne bacteria, and can also be transmitted through soil, diseased plants, etc. There are three obvious symptom peaks in the field for this disease: The first one is in the seedling stage of rice. Generally, it appears about 15 days after sowing. The diseased seedlings are mainly characterized by excessive growth, light yellow leaf color, and then death. The second one appears at the peak tillering stage of rice. The leaf color of the diseased plants becomes lighter, the leaf angle becomes larger, tillering decreases, and adventitious roots grow at the stem node part. The third one appears at the booting stage of rice. The seed setting rate of the diseased plants decreases, white ears appear, and even death occurs. At first glance, it is similar to stem borer damage and bacterial basal rot disease. The first and second peaks have more serious disease incidence. Bakanae disease generally causes a 10% - 20% reduction in rice yield, and in severe cases, the reduction can be more than 50%. In addition, the toxic metabolites produced by the bakanae disease bacteria will also bring serious food safety problems.

[0003] Bakanae disease is known as the "cancer" of rice. It is mainly prevented by soaking seeds with pesticides before sowing, and there is no cure after the disease occurs. At present, there are more than 160 products registered in China for seed treatment to control bakanae disease of rice. Among them, about 85% of the active ingredients of the pesticides are prochloraz, carbendazim or fludioxonil. It is reported that the bakanae disease bacteria have developed serious resistance to a variety of fungicides. To screen out rotation or synergistic composition pesticides suitable for the practice of controlling bakanae disease is the current research focus and hotspot.

[0004] Fludioxonil, common English name: fludioxonil; CAS No.: 131341-86-1; Chemical name: 4-(2,2-difluoro-1,3-benzodioxol-4-yl)pyrrole-3-carbonitrile; Molecular formula: C 12 H6F2N2O2; Molecular weight: 248.185. Fludioxonil is a non-systemic broad-spectrum fungicide. By inhibiting the transfer related to glucose phosphorylation, it inhibits the growth of the mycelium of pathogenic fungi, and finally causes the death of the pathogen. It is used as a seed treatment agent to control seed-borne and soil-borne diseases of crops.

[0005] Hexaconazole, common English name: Hexaconazole, CAS No.: 79983-71-4; Chemical name: (RS)-2-(2,4-dichlorophenyl)-1-(1H-1,2,4-triazol-4-yl)hexan-2-ol; Molecular formula: C 14 H 17 C l2N3O; Molecular weight: 314.21. Hexaconazole belongs to the azole fungicides and is a sterol demethylation inhibitor, which destroys and prevents the biosynthesis of ergosterol, an important component of the pathogen cell membrane, resulting in the inability to form the cell membrane, thereby causing the death of the pathogen. This drug has systemic, protective and therapeutic effects.

[0006] In the prior art, there is no report on their combined use and for the control of bakanae disease of rice. Summary of the Invention

[0007] The present invention provides the following technical solutions:

[0008] A seed treatment suspension, the active ingredients of which are composed of hexaconazole and fludioxonil, and the mass ratio of hexaconazole to fludioxonil is 3:1 - 1:7.

[0009] Preferably, the mass ratio of hexaconazole to fludioxonil is 3:1 - 1:3.

[0010] Preferably, the mass ratio of hexaconazole to fludioxonil is 1:1.

[0011] For the said seed treatment suspension, the weight percentage content of the active ingredients is 1 - 10%; it also contains the following excipients in weight percentage: wetting and dispersing agent 3 - 18%, thickening agent 0.5 - 5%, film-forming agent 1 - 6%, warning agent 1 - 5%, antifreezing agent 1 - 8%, preservative 0.1 - 1.5%, and water is added to make up 100%.

[0012] The said seed treatment suspension contains the following components in weight percentage: fludioxonil 1.5%, hexaconazole 1.5%, Tersperse2500 2%, MorwetD - 390 8%, NNO 2%, polyvinyl alcohol 4%, basic fuchsin 1.5%, sodium benzoate 0.3%, propylene glycol 3%, xanthan gum 0.5%, organic bentonite 1.5%, and deionized water is added to make up 100%.

[0013] The use of the said seed treatment suspension for controlling crop diseases. In particular, the said disease is bakanae disease of rice.

[0014] Adopting the above technical solutions, the present invention has the following beneficial effects:

[0015] The mixture of fludioxonil and hexaconazole has excellent control effects on Fusarium fujikuroi. When the mass ratio of fludioxonil to hexaconazole is 3:1 - 1:7, the mixture has excellent synergistic effects on Fusarium fujikuroi. Among the four ratios, the co-toxicity coefficient is relatively high when the ratio of fludioxonil to hexaconazole is 1:1. The mixture of fludioxonil and hexaconazole is expected to become an effective agent for the field control of bakanae disease of rice.

[0016] In the seed treatment suspending agent prepared by the present invention, when the mass ratio of the wetting and dispersing agents Tersperse 2500, Morwet D-390, and NNO is 8:2:2, the suspending rate, fluidity, water dispersibility in water, and water separation rate after heat storage of the preparation are all relatively good.

[0017] Within the recommended dosage range of the 3% (1.5 + 1.5) fludioxonil · hexaconazole seed treatment suspending agent, no adverse effects on rice and other organisms in the environment were found. Specific Embodiments

[0018] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] The following further explains and illustrates the present invention in conjunction with specific embodiments.

[0020] Example 1: Joint Toxicity Test of Fludioxonil · Hexaconazole Compound on Gibberella fujikuroi of Rice

[0021] 1. Test Purpose

[0022] The mycelial growth rate method was used to determine the toxicity of the single agents of fludioxonil and hexaconazole on Gibberella fujikuroi of rice and the joint toxicity of their mixtures in different proportions, and to determine the optimal formulation of the mixture.

[0023] 2. Materials and Methods

[0024] 2.1 Test Target

[0025] Test pathogen: Fusarium fujikuroi, collected from the field, and the strain was stored for future use after single spore isolation, purification, and identification.

[0026] 2.2 Medicaments

[0027] Fludioxonil technical and hexaconazole technical.

[0028] 2.3 Dosage Setting

[0029] Table 1 Test Dosage Setting of Fludioxonil, Hexaconazole, and Their Mixtures

[0030]

[0031] 2.4 Test Method

[0032] Using the mycelial growth rate method, the preserved Fusarium fujikuroi was transferred to a PDA petri dish and activated at 26°C for 72 h. Then, a 5-mm-diameter mycelial disc was punched out near the colony edge and transferred to a series of PDA petri dishes containing the drug, with the drug-free PDA medium as the blank control. Each treatment was repeated 4 times. After culturing at 26°C for 96 h, when the colony in the control grew to about 4 / 5 of the petri dish diameter, the colony diameter was measured using the cross-cross method. The average colony diameter was calculated, and the average inhibition rate of mycelial growth was calculated according to the formula. Using the DPS data processing system, the EC50 of the drug against the mycelial growth inhibition of Fusarium fujikuroi was calculated.

[0033] 2.5 Calculation method of co-toxicity coefficient

[0034] Calculation was carried out with reference to the co-toxicity coefficient method of Sun Yunpei. The theoretical toxicity index TTI of the mixture = toxicity index of drug A × content of A in the mixture (%) + toxicity index of drug B × content of B in the mixture (%).

[0035]

[0036] If the co-toxicity coefficient CTC of the mixture is greater than 120, it indicates a synergistic effect; if CTC is lower than 80, it indicates an antagonistic effect; if CTC is between 80 - 120, it shows an additive effect.

[0037] 3 Results and evaluation

[0038] Table 2 Test results of the combined effect of fludioxonil and hexaconazole mixture on Fusarium fujikuroi

[0039]

[0040] The results showed that the fludioxonil and hexaconazole mixture had excellent control effects on Fusarium fujikuroi. When the mass ratio of fludioxonil to hexaconazole was 3:1 - 1:7, the mixture had excellent synergistic effects on Fusarium fujikuroi. Among the four ratios, the co-toxicity coefficient was relatively high when the ratio of fludioxonil to hexaconazole was 1:1. The mixture of fludioxonil and hexaconazole is expected to become an effective agent for the field control of bakanae disease in rice.

[0041] Example 2: Preparation of fludioxonil and hexaconazole seed treatment suspension

[0042] 1. Instrument and equipment

[0043] High-shear mixing emulsifier, sand mill, high-performance liquid chromatograph, ultraviolet-visible spectrophotometer, laser particle size distribution analyzer, rotational viscometer, precision pH meter, electrothermal constant temperature drying oven, constant temperature water bath.

[0044] 2. Preparation process

[0045] Prepared by the wet sand grinding method. According to the formulation requirements, other raw materials except the film-forming agent, such as the technical material, wetting and dispersing agent, thickener, warning colorant, antifreeze, preservative, water, etc., are mixed and pre-dispersed. The sample is coarsely pulverized by a high-shear dispersing machine, and then the material is transferred to a sand mill for sand grinding and pulverization. After the sand grinding is completed, the film-forming agent is added and homogenized and stirred to obtain the seed treatment suspension

[0046] 3. Selection of wetting and dispersing agents

[0047] 3.1 Screening of wetting and dispersing agent monomers

[0048] Table 3 Screening of wetting and dispersing agent monomers

[0049]

[0050]

[0051] Note: The contents in the preparation are all weight percentages

[0052] It can be seen from Table 3 that: A single wetting and dispersing agent cannot prepare a seed treatment suspension with excellent performance. Therefore, three wetting and dispersing agents Tersperse 2500, Morwet D-390, and NNO with good suspension rate, fluidity, water dispersion property, and heat storage water separation rate performance indexes of the preparation are selected for compounding and screening experiments

[0053] 3.2 Screening of wetting and dispersing agent compounding

[0054] Table 4 Screening of wetting and dispersing agent compounding

[0055]

[0056]

[0057] Note: The contents in the preparation are all weight percentages

[0058] It can be seen from Table 4 that: When the mass ratio of the wetting and dispersing agents Tersperse 2500, Morwet D-390, and NNO is 8:2:2, the suspension rate, fluidity, water dispersion property, and water separation rate after heat storage of the preparation are all relatively good. Thus, the ratio of Tersperse 2500, Morwet D-390, and NNO is determined to be 8:2:2. That is, formulation 9 is determined as the optimal formulation of the 3% fluxapyroxad · hexaconazole seed treatment suspension, and its performance is detected

[0059] 4. Detection of preparation control item indicators

[0060] Performance detection is carried out with reference to the national standard

[0061] Table 5 Detection Indexes of 3% Fludioxonil · Hexaconazole Seed Treatment Suspension Concentrate

[0062]

[0063]

[0064] As can be seen from Table 5, the prepared 3% fludioxonil · hexaconazole seed treatment suspension concentrate has excellent physical and chemical properties and coating application properties.

[0065] Example 3: Field Efficacy Test of 3% Fludioxonil · Hexaconazole Seed Treatment Suspension Concentrate against Bakanae Disease of Rice (Formulation 9 Medicament)

[0066] 1. Test Object

[0067] Test Object: Bakanae disease of rice

[0068] 2. Test Site and Crop

[0069] Test Site: Demonstration and Propagation Farm in Donggang City, Liaoning Province. This area has a long history of rice cultivation, and bakanae disease of rice often occurs. The rice in the test field was dressed with seeds on April 18th and transplanted on June 2nd. Manual transplanting was used, with a row spacing of 30 cm and a plant spacing of 18 cm. Field management was carried out according to local customs.

[0070] Test Crop, Variety

[0071] Rice: "Koshihikari".

[0072] 3. Main Instruments

[0073] Electronic balance, instrument numbers: 2018FPT002, 2018FPT003; Pipettor, instrument number: 2018GPY003; Electronic balance (for yield measurement), instrument number: 2020HPT004.

[0074] 4 Meteorological and Soil Data

[0075] 4.1 Meteorological Data

[0076] On the day of pesticide application, it was cloudy, with an average temperature of 8.3 °C, a maximum temperature of 15.3 °C, a minimum temperature of 2.1 °C, a relative air humidity of 66.3%, a daily precipitation of 0 mm, and a sunshine duration of 11.9 h. See Appendix 1 for the meteorological conditions on the day of pesticide application and during the test period.

[0077] 4.2 Soil Data

[0078] The fertility of this plot is uniform. It is an old paddy field with a 40-year history of rice cultivation. The soil type is paddy soil, and the pH value is 7.0.

[0079] 5 Test Schedule

[0080] Pilot project start date: April 12, 2021

[0081] Trial start date: April 18, 2021

[0082] Application date: April 18, 2021

[0083] Date of first survey of the trial: April 30, 2021

[0084] Second survey date of the trial: May 25, 2021

[0085] Date of the third survey of the trial: July 29, 2021

[0086] Trial completion date: July 29, 2021

[0087] 6 Experimental treatment and investigation

[0088] Application method

[0089] (1) Application method: seed coating method.

[0090] (2) Application equipment: None.

[0091] (3) Application time and frequency: Application was conducted on April 18, 2021, and once during the entire growing season.

[0092] Survey, Recording and Statistical Methods

[0093] Crop safety survey

[0094] The seedbed was sown quantitatively, 100 seeds were sown for each treatment, and the emergence rate was investigated when the seedlings were all grown. Each treatment was repeated 4 times. Before rice transplanting, sampling was conducted at five diagonal points, and the fresh weight of the aboveground part and the underground part of 100 plants were investigated at each point. Each treatment was repeated 4 times.

[0095] Experimental investigation

[0096] Before transplanting, sampling surveys were conducted at five diagonal points, 100 seedlings were randomly surveyed at each point, the number of diseased plants was recorded, and each treatment was repeated 4 times.

[0097] Five random sampling points were taken in each plot before heading in the field, 10 clumps were investigated at each point, and the total number of plants and the number of diseased plants were recorded. Each treatment was repeated 4 times.

[0098] Impact on other organisms

[0099] Record the effects of the test agent on non-target organisms in the test area.

[0100] Statistical analysis methods for test data

[0101] Using Excel and SPSS software, the Duncan's new multiple range test (DMRT) was used to statistically analyze the experimental data and evaluate the experimental results.

[0102] Pharmacodynamic calculation method:

[0103]

[0104]

[0105]

[0106] 7. Experimental results and analysis

[0107] 7.1 Safety for crops

[0108] When the rice emerged uniformly, the seed emergence rate was investigated. The experimental results showed that for the 3% fludioxonil · hexaconazole seed treatment suspension at doses of 400 ml / 100 kg dry seeds, 500 ml / 100 kg dry seeds, and 600 ml / 100 kg dry seeds, the seed emergence rates were 94.25%, 95.25%, and 94.00% respectively. The seed emergence rate of the blank control was 94.50%. The detailed results are shown in Table 6 below.

[0109] Table 6 Experimental results of 3% fludioxonil · hexaconazole seed treatment suspension for controlling bakanae disease in rice - emergence rate

[0110]

[0111]

[0112] Before transplanting the rice, the fresh weight of the above-ground part and the fresh weight of the underground part of the seedlings were investigated. The experimental results showed that for the 3% (1.5 + 1.5) fludioxonil · hexaconazole seed treatment suspension at doses of 400 ml / 100 kg dry seeds, 500 ml / 100 kg dry seeds, and 600 ml / 100 kg dry seeds, the fresh weight of 100 plants in the above-ground part was 17.02 g, 16.95 g, and 17.40 g respectively, and the fresh weight of 100 plants in the underground part was 6.68 g, 6.86 g, and 6.79 g respectively. The fresh weight of 100 plants in the above-ground part of the blank treatment was 16.67 g, and the fresh weight of 100 plants in the underground part was 6.61 g. The detailed results are shown in Table 7 below.

[0113] Table 7 Experimental results of 3% fludioxonil · hexaconazole seed treatment suspension for controlling bakanae disease in rice - fresh weight

[0114]

[0115] 7.2 Control effect on bakanae disease of rice

[0116] Investigation results before transplanting showed that for the 3% (1.5 + 1.5) fluxapyroxad·hexaconazole seed treatment suspension agent at dosages of 400 ml / 100 kg dry seeds, 500 ml / 100 kg dry seeds, and 600 ml / 100 kg dry seeds, the control effects against rice bakanae disease were 84.26%, 85.63%, and 93.35% respectively. The detailed results are shown in Table 8 below.

[0117] Table 8 Experimental results of 3% fluxapyroxad·hexaconazole seed treatment suspension agent for controlling rice bakanae disease - Control effect before transplanting

[0118]

[0119]

[0120] Investigation results at the booting stage showed that for the 3% (1.5 + 1.5) fluxapyroxad·hexaconazole seed treatment suspension agent at dosages of 400 ml / 100 kg dry seeds, 500 ml / 100 kg dry seeds, and 600 ml / 100 kg dry seeds, the control effects against rice bakanae disease were 77.31%, 84.33%, and 91.94% respectively. The detailed results are shown in Table 9 below.

[0121] Table 9 Experimental results of 3% fluxapyroxad·hexaconazole seed treatment suspension agent for controlling rice bakanae disease - Control effect at the booting stage

[0122]

[0123] 8 Conclusions

[0124] The 3% (1.5 + 1.5) fluxapyroxad·hexaconazole seed treatment suspension agent can effectively control rice bakanae disease with good control effects, is safe for rice within the recommended dosage range, and is suitable for popularization and application in northern rice fields.

[0125] Optimal application period: Before sowing the seeds. Recommended dosage: The dosage for northern rice fields is 400 ml / 100 kg dry seeds to 600 ml / 100 kg dry seeds. Application method: Seed coating method.

[0126] Within the recommended dosage range of the 3% (1.5 + 1.5) fluxapyroxad·hexaconazole seed treatment suspension agent, no adverse effects on rice and other organisms in the environment were found.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them.

Claims

1. A seed treatment suspension concentrate, characterized in that, The active ingredient consists of hexaconazole and fludioxonil, and the mass ratio of hexaconazole to fludioxonil is 3:1 - 1:

7.

2. The seed treatment suspending agent according to claim 1, wherein The mass ratio of hexaconazole to fludioxonil is 3:1 - 1:

3.

3. The seed treatment suspension agent according to claim 2, wherein, The mass ratio of hexaconazole to fludioxonil is 1:

1.

4. The seed treatment suspension agent according to any one of claims 1 to 3, characterized in that, The weight percentage content of the active ingredient is 1 - 10%; the following excipients are also included with the following weight percentage contents: wetting and dispersing agent 3 - 18%, thickening agent 0.5 - 5%, film-forming agent 1 - 6%, warning agent 1 - 5%, antifreeze 1 - 8%, preservative 0.1 - 1.5%, and water is added to make up 100%.

5. The seed treatment suspending agent according to any one of claims 1 to 3, characterized in that, It contains the following components with the following weight percentage contents: fludioxonil 1.5%, hexaconazole 1.5%, Tersperse 2500 2%, Morwet D - 390 8%, NNO 2%, polyvinyl alcohol 4%, basic rhodamine 1.5%, sodium benzoate 0.3%, propylene glycol 3%, xanthan gum 0.5%, organic bentonite 1.5%, and deionized water is added to make up 100%.

6. Use of the seed treatment suspension agent according to any one of claims 1 - 3 for controlling bakanae disease of rice caused by Fusarium fujikuroi.

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