A bactericidal composition comprising methamidophos and fluthiazopyrone and its application.

Abstract

This invention belongs to the field of agricultural fungicides, and provides a fungicidal composition comprising methamidophos and fluthiazopyrone and its application. The active ingredients are composed of methamidophos and fluthiazopyrone, with a mass ratio of methamidophos to fluthiazopyrone of 1:1 to 1:20. The fungicidal composition has excellent synergistic effects against crop diseases, can effectively reduce the amount of pesticides used, slow down the development of pesticide resistance in diseases, reduce environmental pollution, and is safe for crops in field observations.

Description

Technical Field

[0001] This invention belongs to the field of agricultural fungicides, specifically relating to a fungicidal composition comprising methylthiazolinone and fluthiazolinone and its application. Background Technology

[0002] Downy mildew in cucumbers is caused by *Pseudomonas columbia*, a fungus belonging to the genus *Pseudomonas* of the subphylum Oomycetes. The sporangia of this fungus are spread by air currents and rainwater. Downy mildew primarily affects the leaves. In seedlings, the cotyledons turn pale green, gradually forming irregular yellow lesions. In mature plants, the disease initially appears as light green, water-soaked spots on the leaves, which expand and are restricted by leaf veins, becoming polygonal, turning from yellowish-green to brown. Later, the lesions merge into patches, causing the entire leaf to dry out, and in severe cases, the entire plant dies.

[0003] Using chemical agents to control cucumber downy mildew has the advantages of significant efficacy, ease of use, and rapid results. However, chemical control poses risks to human and animal safety, causes environmental pollution due to pesticide residues, and long-term use of single agents can lead to increased disease resistance. Pesticide formulation is a way to reduce the development of disease resistance, especially fungicide combinations with synergistic effects. These can delay or overcome the development of resistance after pesticides have screened harmful organisms, reduce costs, and thus alleviate environmental safety issues associated with pesticide use.

[0004] Methiazolyl is a thiadiazole plant disease activator jointly developed by Nankai University. CN100420686C discloses the synthesis method of methiazolyl and also discloses its excellent control effects against *Fusarium wilt* of cucumber, *Fusarium graminearum* of wheat, *Fragaria oryzae* of rice, *Sclerotinia sclerotiorum* of rapeseed, *Pseudomonas ulcerans*, *Anthracnose* of banana, *Anthracnose* of cucumber, *Verticillium wilt* of cotton, and late blight of potato. CN101091490A discloses its excellent control effect against downy mildew of cucumber. Current research results show that this compound has a good inducing effect on viral diseases, and its mechanism of action is to induce systemic and broad-spectrum resistance activity in plants.

[0005] Fluoxazolidinone is a fungicide developed by DuPont. It achieves its fungicidal effect by inhibiting oxidized sterol-binding protein (OSBP). It has protective, curative, and sporulation-inhibiting effects on pathogens and exhibits excellent fungicidal activity against oomycete diseases. This product is rapidly absorbed by the waxy layer and has excellent resistance to rain washout. It also possesses systemic-to-apical translocation properties and protects newly formed tissue.

[0006] There are no existing reports on the use of a combination of methicillin and fluthiazopyrone for the control of cucumber downy mildew. Summary of the Invention

[0007] This invention provides a bactericidal composition with excellent synergistic effects, the specific technical solution of which is as follows:

[0008] A bactericidal composition comprising methoxyfenozide, wherein the active ingredients are composed of methoxyfenozide and fluthiazopyrone, and the mass ratio of methoxyfenozide to fluthiazopyrone is 1:1 to 1:20.

[0009] The mass ratio of methoxyfenozide and fluthiazopyrone in the bactericidal composition is 1:5-1:20.

[0010] The mass ratio of methoxyfenozide and fluthiazopyrone in the bactericidal composition is 1:5, 1:10, 1:15, or 1:20.

[0011] The bactericidal composition contains adjuvants, and the weight percentage of the active ingredient is 1-85%. Preferably, the weight percentage of the active ingredient is 10-60%.

[0012] The additives are one or more of the following: wetting agents, emulsifiers, dispersants, suspending agents, antifreeze agents, thickeners, defoamers, solvents, and fillers.

[0013] The bactericidal composition is formulated as a dispersible oil suspension, an aqueous suspension, a wettable powder, a water-dispersible granule, or a microemulsion.

[0014] The bactericidal composition is used for the prevention and control of crop diseases. Preferably, the crop disease is cucumber downy mildew.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects:

[0016] When the mass ratio of methamidophos to fluthiazopyrone is 1:5-1:20, the composition exhibits a significant synergistic effect against cucumber downy mildew, with a CTC value significantly greater than 120. This effectively reduces pesticide usage, slows the development of pesticide resistance, and mitigates environmental pollution. The tested agent of this invention demonstrates excellent control efficacy against cucumber downy mildew, with field efficacy exceeding 90%, and its safety for cucumbers was observed during addition. Detailed Implementation

[0017] The present invention will be further explained below with reference to specific embodiments.

[0018] Example 1: Pot test of the combination of methylthiamethoxam and fluthiazopyrone against cucumber downy mildew.

[0019] Experimental materials:

[0020] The fungus causing cucumber downy mildew (Pseudoperonospora cubensis); field collection and identification, and indoor in vivo culture and preservation.

[0021] Test method:

[0022] Refer to Part 7 of the "Guidelines for Indoor Bioassay Testing of Pesticides: Fungicides"—Test on Control of Cucumber Downy Mildew—Pot Method. Select potted cucumber seedlings of uniform growth for the experiment; the seedlings should be at the 4-5 leaf stage. Prepare a 1×10⁻⁶ concentration... 6 A CFU / mL sporangium suspension was evenly sprayed onto the underside of cucumber leaves using an inoculation sprayer until the surface was moist. After spraying inoculation, the leaves were moved to an artificial climate chamber with a relative humidity >90% and a temperature of 22℃. Foliar spraying was performed 24 hours later (the concentration gradient of the pesticide was determined based on preliminary experiments), and disease surveys were conducted 14 days later.

[0023] Grading standards:

[0024] Level 0: No disease;

[0025] Grade 1: The area of ​​lesions accounts for less than 5% of the total leaf area;

[0026] Grade 3: The lesion area accounts for 6% to 10% of the total leaf area;

[0027] Level 5: The lesion area accounts for 11% to 25% of the total leaf area;

[0028] Level 7: The lesion area accounts for 26% to 50% of the total leaf area;

[0029] Level 9: The lesion area accounts for more than 50% of the total leaf area.

[0030] Calculation of drug efficacy:

[0031]

[0032]

[0033] Regression analysis was performed based on the concentrations of each single agent and combination, and their corresponding efficacy, to determine the EC50 of each agent. 50 value.

[0034] Using the co-toxicity coefficient method calculated by Sun Yunpei, the co-toxicity coefficient (CTC) of the mixture was calculated to determine the synergistic effect of the mixture.

[0035] Single-dose toxicity index = (EC50 of standard dose) 50 / A single-dose EC 50 )×100;

[0036] Theoretical toxicity index (TT I) = toxicity index of single agent A × proportion of single agent A in the mixture + toxicity index of single agent B × proportion of single agent B in the mixture;

[0037] Measured toxicity index (ATI) = (EC50 of standard single dose) 50 EC values / mixtures50 (value) × 100;

[0038] Cotoxicity coefficient (CTC) = (Measured toxicity index / Theoretical toxicity index) × 100;

[0039] When CTC is greater than 120, the mixture has a synergistic effect; when CTC is less than 80, it has an antagonistic effect; and when CTC is between 80 and 120, it has an additive effect.

[0040] Test Results

[0041] Table 1 shows that methamidophos has an EC50 effect on cucumber downy mildew. 50 The EC50 value of fluoxazolylpyrrolizidine ketone against cucumber downy mildew was 8.4638 mg / L. 50 The concentration of the compound was 0.0035 mg / L. When the mass ratio of methoxyfenozide to fluthiazopyrone was 1:5-1:20, the composition showed a significant synergistic effect against cucumber downy mildew, with a CTC value significantly greater than 120. When the mass ratio of methoxyfenozide to fluthiazopyrone was 20:1-1:1, the composition showed an additive effect against cucumber downy mildew. When the composition showed a significant synergistic effect, it could effectively reduce the dosage of the active ingredient and slow down the development of drug resistance in the pathogen.

[0042] Table 1: Indoor test results of the combination of methamidophos and fluthiazopyrone against cucumber downy mildew.

[0043]

[0044] Example 2: Field efficacy test of the combination of methamidophos and fluthiazopyrone against cucumber downy mildew.

[0045] Test crop disease: Cucumber downy mildew

[0046] Test reagent:

[0047] 22% Methionamide and Fluthiazopyrone Suspension Contains the following ingredients in percentage: Methionamide 2%, Fluthiazopyrone 20%, NNO 4%, Morwet D-425 3%, Sodium Dodecylbenzene Sulfonate 3%, Xanthan Gum 0.4%, Glycerol 3%, Dimethyl Silicone Oil 0.4%, Organobentonite 0.2%, Deionized Water to make up 100%.

[0048] 12% Methionamide and Fluthiazopyrone Suspension Contains the following ingredients in percentage: Methionamide 2%, Fluthiazopyrone 10%, NNO 2%, Morwet D-425 4%, Sodium Dodecylbenzene Sulfonate 2%, Xanthan Gum 0.5%, Glycerol 4%, Dimethyl Silicone Oil 0.5%, Organobentonite 0.2%, Deionized Water to make up 100%.

[0049] 21% Methiazolinone and Fluthiazolinone wettable powder contains the following ingredients by weight percentage: Methiazolinone 1%, Fluthiazolinone 20%, Spreading powder 5%, Dodecane NNO 2%, Calcium lignosulfonate 3%, Silica 5%, and Kaolin to make up 100%.

[0050] 32% Methiazolinone and Fluthiazolinone wettable powder contains the following ingredients by weight percentage: Methiazolinone 2%, Fluthiazolinone 30%, Spreading powder 4%, Dodecane NNO 5%, Calcium lignosulfonate 4%, Silica 5%, and Kaolin to make up 100%.

[0051] Experimental method: Refer to "Guidelines for Field Efficacy Testing of Pesticides (I) - Control of Cucumber Downy Mildew with Fungicides". Plot setup: Each plot is 45m². 2 The experiment was conducted in a randomized block design, with each treatment replicated four times. The pesticide was applied at the early stage of cucumber downy mildew infection by foliar spraying, with the spray volume being just enough to avoid dripping. One application was made, and the disease incidence was assessed before the first application and the disease index was assessed 21 days after the second application to calculate the control efficacy.

[0052] Investigation method: Five points were randomly selected in each area for investigation, with two plants investigated at each point. All leaves of each plant were investigated, and the total number of leaves and the number of diseased leaves at each level were recorded.

[0053] Grading standards:

[0054] Level 0: No disease;

[0055] Grade 1: The area of ​​lesions accounts for less than 5% of the total leaf area;

[0056] Grade 3: The lesion area accounts for 6% to 10% of the total leaf area;

[0057] Level 5: The lesion area accounts for 11% to 25% of the total leaf area;

[0058] Level 7: The lesion area accounts for 26% to 50% of the total leaf area;

[0059] Level 9: The lesion area accounts for more than 50% of the total leaf area.

[0060] Calculation of drug efficacy:

[0061]

[0062]

[0063] CK0 - Disease index before drug administration in the blank control area; CK1 - Disease index after drug administration in the blank control area; PT0 - Disease index before drug administration in the drug-treated area; PT1 - Disease index after drug administration in the drug-treated area.

[0064] Test Results

[0065] As shown in Table 2, the tested agents of this invention have excellent control effects on cucumber downy mildew, with field control efficacy of over 90%, and the addition of these agents to cucumbers was observed to be safe.

[0066] Table 2: Field control efficacy of the combination of methamidophos and fluthiazopyrone against cucumber downy mildew.

[0067]

[0068]

[0069] Finally, it should be noted that the above examples are merely a few specific embodiments of the present invention. All modifications that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention are considered to be within the scope of protection of this invention.

Claims

1. A bactericidal composition comprising methimazole, characterized in that, The active ingredients consist of methylthiazolinone and fluthiazolinone, with a mass ratio of methylthiazolinone to fluthiazolinone of 1:5 to 1:

20.

2. The bactericidal composition according to claim 1, characterized in that, The mass ratio of methimazole and fluthiazopyrone is 1:10, 1:15 or 1:

20.

3. The bactericidal composition according to any one of claims 1-2, characterized in that, The bactericidal composition contains adjuvants, and the weight percentage of the active ingredient is 1-85%.

4. The bactericidal composition according to claim 3, characterized in that, The weight percentage of active ingredients is 10-60%.

5. The bactericidal composition according to claim 3, characterized in that, The additives are one or more of the following: wetting agents, emulsifiers, dispersants, suspending agents, antifreeze agents, thickeners, defoamers, solvents, and fillers.

6. The bactericidal composition according to claim 5, characterized in that, The bactericidal composition is formulated as a dispersible oil suspension, an aqueous suspension, a wettable powder, a water-dispersible granule, or a microemulsion.

7. The use of the bactericidal composition according to any one of claims 1-6 for the prevention and control of crop diseases, characterized in that, The crop diseases mentioned above are due to Pseudoperonospora cubensis This causes downy mildew in cucumbers.

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