Application of fluxapyroxad-epoxiconazole bactericidal composition in prevention and treatment of corn southern rust disease

Abstract

The invention discloses application of a fluxapyroxad-epoxiconazole bactericidal composition in prevention and treatment of southern corn rust, and belongs to the technical field of pesticides. The active ingredients of the fluxapyroxad-epoxiconazole bactericidal composition disclosed by the invention comprise fluxapyroxad and epoxiconazole, wherein the weight ratio of the fluxapyroxad to the epoxiconazole is (1: 9)-(1: 1). The effect of the mixture of the fluxapyroxad and the epoxiconazole for preventing and treating the corn southern rust disease is obviously higher than that of a single component, the synergistic effect is remarkable when the fluxapyroxad and the epoxiconazole are matched within the range of 1: 9-1: 1, and the optimal ratio is 1: 3. The dosage of the pesticide can be reduced, the control effect is improved, the use cost is reduced, the pesticide resistance of the pesticide is delayed, and the safety to crops and the environment is improved.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to application of a fluopyraclostrobin-epoxiconazole fungicide composition in preventing and controlling southern corn rust. Background Art

[0002] Corn southern rust is a common disease in tropical and subtropical corn-growing areas. The pathogen that causes the rust is Puccinia maydis, which likes heat and fears cold, likes high humidity and fears drought. Therefore, corn southern rust occurs more severely in areas with more rainfall. In recent years, affected by typhoons, summer corn in the Huanghuaihai region has also tended to become more severe. After southern rust infects corn, it first appears as small chlorotic spots on the middle and lower leaves of the corn plant, which quickly develop into yellow-brown raised blisters, which are the summer spores of the pathogen. Then the summer spores produced by the pathogen spread with wind and rain and cause damage. In a corn growing season, the pathogen can re-infect multiple times, and the diseased plant rate and diseased leaf rate continue to rise, from spot occurrence to widespread disease. The disease also develops from the lower leaves to the upper leaves, causing the corn leaves to dry up prematurely, seriously affecting corn yield and quality.

[0003] Fluopyrab is a bifenthionamide fungicide developed by BASF. It belongs to the succinate dehydrogenase inhibitor (SDHI) fungicide class. It inhibits the succinate dehydrogenase of the respiratory electron transport chain complex II, prevents it from producing energy, inhibits the growth of pathogens, and eventually causes their death, thereby achieving the purpose of preventing and controlling diseases. It can inhibit spore germination, germ tube elongation, mycelial growth and spore formation, has no cross-resistance with triazole fungicides, has the characteristics of broad spectrum, high efficiency and long lasting effect, and has been registered in the United States, China, Australia, Canada, New Zealand, EU countries and other countries. It is mainly used for crops such as grains, soybeans, corn, vegetables, fruits, and cash crops to prevent and control a variety of diseases through foliar or seed treatment.

[0004] Fluoxiconazole is a systemic triazole fungicide. Its mechanism of action is as an inhibitor of C-14 demethylase in sterol biosynthesis. It hinders the formation of bacterial cell walls and has both protective and therapeutic effects. Fluoxiconazole can increase the chitinase activity of crops, leading to the contraction of fungal haustoria and inhibiting the invasion of pathogens. This is a unique feature among triazole fungicides. It has good preventive effects on leaf spot, powdery mildew, rust on crops such as bananas, onions, garlic, celery, beans, melons, asparagus, peanuts, and beets, as well as anthracnose and white rot on grapes.

[0005] There are reports in the prior art on the use of fluopyram and epoxiconazole in combination for controlling rice sheath blight and banana leaf spot, but there are no reports on the use of fluopyram and epoxiconazole in combination for controlling southern corn rust. Summary of the invention

[0006] In view of the above-mentioned prior art, the object of the present invention is to provide an application of a fluopyraclostrobin-epoxiconazole fungicidal composition in preventing and controlling southern corn rust.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides the use of a trifloxystrobin-epoxiconazole fungicide composition in at least one of the following (1)-(3):

[0009] (1) Inhibit the germination of spores of southern corn rust (Puccinia polysora Underw);

[0010] (2) Prevent and control southern corn rust;

[0011] (3) Prepare products for preventing and controlling southern corn rust.

[0012] In the above application, the weight ratio of the fluopyrabamide to epoxiconazole in the fluopyrabamide-epoxiconazole fungicidal composition is 1:9 to 1:1.

[0013] Further preferably, in the fluopyrabactam-epoxiconazole fungicidal composition, the weight ratio of fluopyrabactam to epoxiconazole is 1:3.

[0014] The fluopyram-epoxiconazole fungicide composition is currently mainly used for field control of rice sheath blight and banana leaf spot. In order to further broaden its application scope, the present invention has found through experimental research that the fungicide composition composed of fluopyram and epoxiconazole in a certain ratio has an inhibitory effect on the spore germination of the pathogen of southern corn rust, and can thus be used for the control of southern corn rust. Moreover, the ratio between fluopyram and epoxiconazole will directly affect the control effect of the fungicide composition on southern corn rust. When the weight ratio of the two is 1:3, it has the best control effect on southern corn rust.

[0015] A second aspect of the present invention provides a method for preventing and controlling southern corn rust, comprising the following steps:

[0016] At the early stage of southern corn rust, the above-mentioned fluopyraclostrobin-epoxiconazole fungicidal composition is sprayed on the above-ground part of corn plants.

[0017] The third aspect of the present invention provides an agent for preventing and controlling southern corn rust, wherein the agent contains an effective amount of the above-mentioned fluopyraclostrobin-epoxiconazole fungicidal composition.

[0018] Preferably, in the agent, the weight percentage of the fluopyraclostrobin-epoxiconazole fungicide composition is 5-60%.

[0019] Furthermore, the dosage form of the drug can be granules, powders, suspensions, aqueous solutions, aqueous emulsions, sustained-release preparations, tablets, etc.

[0020] The fourth aspect of the present invention provides the use of the above-mentioned agent in the prevention and control of southern corn rust.

[0021] Beneficial effects of the present invention:

[0022] The present invention found that fluopyram and epoxiconazole have strong inhibitory activity on the germination of spores of southern corn rust pathogen; the effect of fluopyram and epoxiconazole mixed for the prevention and control of southern corn rust is significantly higher than that of a single component, and the synergistic effect of the two is significant in the range of 1:9 to 1:1, among which 1:3 is the best ratio. It can reduce the dosage of the agent, improve the prevention and control effect, reduce the cost of use, delay the resistance of the agent, and improve the safety of crops and the environment. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0024] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific examples. If the specific experimental conditions are not specified in the examples, they are usually in accordance with conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples and comparative examples, unless otherwise specified, can be obtained through commercial channels.

[0025] Example 1: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0026] Fluopyrab and epoxiconazole are mixed in a weight ratio of 1:1 to form a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0027] Example 2: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0028] Fluopyrab and epoxiconazole were mixed in a weight ratio of 1:3 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0029] Example 3: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0030] Fluopyrab and epoxiconazole were mixed in a weight ratio of 1:6 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0031] Example 4: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0032] Fluopyrab and epoxiconazole were mixed in a weight ratio of 1:9 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0033] Example 5: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0034] Fluopyrab and epoxiconazole were mixed in a weight ratio of 1:12 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0035] Example 6: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0036] Fluopyrab and epoxiconazole were mixed in a weight ratio of 3:1 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0037] Example 7: Preparation of Fluopyraclostrobin-Epoxiconazole fungicidal composition

[0038] Fluopyrab and epoxiconazole were mixed in a weight ratio of 6:1 to prepare a fluopyrab-epoxiconazole fungicide composition for preventing and controlling southern corn rust.

[0039] Application example: Indoor toxicity test of a mixture of fluopicolide and epoxiconazole against southern corn rust pathogen

[0040] 1. Test pathogen: Southern corn rust (Puccinia polysora Underw).

[0041] 2. Test methods:

[0042] Refer to the spore germination concave slide method (NY / T 1156.1-2006) and the combined action determination of fungicide mixtures (NY / T 1156.6-2006) in the "Guidelines for Indoor Bioassay Tests of Pesticides" (NY / T 1156.1-2006). Use a pipette or a pipette to draw 1 mL from low concentration to high concentration and add them to small test tubes, and then draw 1 mL of the prepared spore suspension to make the drug solution and spore suspension equal and mix evenly.

[0043] Use a micropipette to draw the above mixed solution and drop it onto a concave glass slide, then place it in a culture dish with a shallow layer of water, cover it to keep it moist, and culture it in an incubator at a suitable temperature. Repeat each treatment for no less than 4 times, and set a treatment without the drug as a blank control. Culture it in a light biochemical incubator at 28°C and a relative humidity of 90% for 5 hours.

[0044] When the spore germination rate of the blank control reaches more than 90%, check the spore germination of each treatment. Since the spore germination rate of southern corn rust is relatively low, the spore germination of each treatment is checked when the spore germination rate of the blank control reaches more than 85% during the test.

[0045] For each treatment, randomly observe more than three fields of view repeatedly, investigate a total of no less than 200 spores, and record the germination number and the total spore number respectively. When the length of the spore germ tube is greater than the short radius of the spore, it is regarded as germination.

[0046] If the inhibition rate of spore germination in the blank control is less than 5%, no correction is required; if the inhibition rate of spore germination in the blank control is between 5% and 20%, calculate the corrected inhibition rate of each treatment using the Abott formula; if the inhibition rate of spore germination in the blank control is more than 20%, the experiment needs to be repeated.

[0047] Based on the survey data, calculate the relative inhibition rate of spore germination for each treatment, with the unit of percentage (%). Calculate the control effect of each treatment concentration according to the formula, and then use DPS data processing software to calculate the experimental results, and find the toxicity regression equation, EC 50 and EC 90 as well as the 95% confidence limit, and calculate the co-toxicity coefficient (CTC) of different ratios of the two agents to screen out the best ratio of the test agents. Record the original data of all replicates for each treatment.

[0048] Corrected inhibition rate (%) = (spore germination rate in the blank control - spore germination rate in the treatment) / spore germination rate in the blank control × 100

[0049] And calculate the co-toxicity coefficient (CTC) of the compound agent mixture according to the method of Sun Yunpei. The calculation formula of the co-toxicity coefficient (CTC) is as follows:

[0050] Actual toxicity index (ATI) = (EC50 of the standard agent / EC 50 ) × 100

[0051] Theoretical toxicity index (TTI) = toxicity index of agent A × percentage content of agent A in the mixture + toxicity index of agent B × percentage content of agent B in the mixture

[0052] Co-toxicity coefficient (CTC) = (ATI / TTI) × 100

[0053] According to the classification standard of the co-toxicity coefficient (CTC), CTC ≤ 80 indicates antagonism, 80 < CTC < 120 indicates additive effect, and CTC ≥ 120 indicates synergistic effect.

[0054] 3. Experimental results:

[0055] The experimental results are shown in Table 1.

[0056] Table 1: Results of indoor combined toxicity determination of fluxapyroxad and epoxiconazole against the pathogen of southern rust of maize

[0057]

[0058] From the results in Table 1, it can be seen that the inhibitory activity of fluopyram and epoxiconazole on the spore germination of southern corn rust is very high. 50 The ratios were 0.0079 mg / L and 0.0230 mg / L respectively. The co-toxicity coefficient (CTC) of the two in the range of 1:9 to 1:1 was greater than 120, with significant synergistic effects. They showed high activity against southern corn rust pathogens, with 1:3 being the best ratio.

[0059] In summary, the fungicidal composition of fluopyram and epoxiconazole described in the present invention has a significant synergistic effect, can reduce the dosage of the agent, improve the effect of preventing and controlling southern corn rust, reduce the cost of use, delay the resistance of the agent, and improve the safety of crops and the environment.

[0060] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. Use of the trifloxystrobin-epoxiconazole fungicidal composition in at least one of the following (1)-(3): (1) Inhibit the germination of spores of southern corn rust (Puccinia polysora Underw); (2) Prevent and control southern corn rust; (3) Prepare products for preventing and controlling southern corn rust.

2. The use according to claim 1, characterized in that: In the fluopyrabactam-epoxiconazole fungicidal composition, the weight ratio of fluopyrabactam to epoxiconazole is 1:9 to 1:

1.

3. The use according to claim 1 or 2, characterized in that: In the fluopyrabactam-epoxiconazole fungicidal composition, the weight ratio of fluopyrabactam to epizotoxin is 1:

3.

4. A medicament for preventing and treating southern corn rust, characterized in that: The agent contains an effective amount of the fluopyraclostrobin-epoxiconazole fungicidal composition according to claim 1.

5. The medicament according to claim 4, characterized in that The dosage form of the medicine is granules, powders, suspensions, aqueous solutions, aqueous emulsions, sustained-release preparations or tablets.

6. Use of the agent according to claim 4 or 5 in the prevention and treatment of southern corn rust.

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