Bactericidal composition and application thereof in prevention and treatment of maize dwarf mosaic disease

Abstract

The invention discloses a bactericidal composition and application thereof in prevention and treatment of maize dwarf mosaic disease, and belongs to the technical field of pesticides. The active ingredients of the bactericidal composition comprise carvacrol and chlorobromoisocyanuric acid, and the weight ratio of the carvacrol to the chlorobromoisocyanuric acid is 1: 1-1: 15. According to the invention, the effect of the mixture of carvacrol and chlorobromoisocyanuric acid for preventing and treating the maize dwarf mosaic disease is obviously higher than that of a single component, the synergistic effect of carvacrol and chlorobromoisocyanuric acid is obvious when the ratio of carvacrol to chlorobromoisocyanuric acid is 1: 1-1: 15, and the optimal ratio is 1: 5. The dosage of the pesticide can be reduced, the control effect is improved, the use cost is reduced, 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 a fungicide composition and application thereof in preventing and controlling corn dwarf mosaic disease. Background Art

[0002] Maize dwarf mosaic disease (MDM) is an important viral disease that harms maize production. The pathogens that are known to cause dwarf mosaic disease include Sugarcane mosaic virus (SCMV) and Maize dwarf mosaic virus (MDMV). Maize dwarf mosaic virus is a quarantine object in my country and rarely occurs in production; Sugarcane mosaic virus is a common virus in my country's main maize producing areas, causing maize dwarf mosaic disease. Since the 1990s, this disease has occurred in many maize producing areas in my country, causing a 30% to 50% reduction in maize yield, and even a total crop failure in some plots.

[0003] Many methods have been tried to prevent and control corn dwarf mosaic, such as crop rotation, breeding of disease-resistant varieties, seed detoxification, use of cross-protection, prevention and control of virus vectors, and disease-resistant genetic engineering. However, chemical control is rarely used in production. The fundamental reason is that viruses are absolute parasites of nucleoprotein macromolecules, and they are more dependent on plants than fungi and bacteria, and have a closer relationship with them. Although thousands of antiviral substances with certain activity against different viruses have been discovered so far, they are often difficult to reach the level of application in production due to their low activity. There is still a lack of targeted chemical control agents for corn dwarf mosaic.

[0004] Carvacrol is a volatile oil that is light yellow, transparent, and has a strong aroma. It is an aromatic compound. Oregano, thyme, lobelia, eastern perilla, and balsam pear all contain carvacrol. Carvacrol can destroy the integrity of cell walls and cell membranes, affect the synthesis of microbial DNA, RNA, and proteins, and has a broad spectrum of antibacterial activity. It has a preventive and control effect on gray mold, late blight, powdery mildew, rust, tobacco virus disease, apple spider mites, and tea green leafhoppers.

[0005] Chlorobromoisocyanuric acid is a low-toxic, high-efficiency, broad-spectrum, systemic fungicide. Its mechanism of action is that it can slowly release Cl and Br when sprayed on the surface of crops to form hypochlorous acid (HCIO) and (HBrO) molecules. It has a good control effect on bacteria, fungi and viruses. In agricultural production, it can be used to prevent and control various diseases such as Chinese cabbage soft rot, rice sheath blight, rice blast, various bacterial diseases, tobacco brown spot disease, cucumber downy mildew, pepper blight and tobacco virus disease.

[0006] There is no related report in the prior art on the use of a combination of carvacrol and chlorobromoisocyanuric acid for preventing and controlling corn dwarf mosaic disease. Summary of the invention

[0007] In view of the above prior art, the purpose of the present invention is to provide a fungicide composition and its application in preventing and treating corn dwarf mosaic disease. The present invention scientifically mixes carvacrol and chlorobromoisocyanuric acid to clarify the synergistic ratio of the two, which has a significant synergistic effect and effectively reduces the dosage, and can be used for preventing and treating corn dwarf mosaic disease.

[0008] To achieve the above object, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention provides a fungicide composition, which is composed of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1: (1-15).

[0010] Preferably, the bactericidal composition consists of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1:(5-10).

[0011] More preferably, the fungicidal composition consists of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1:5.

[0012] The present invention finds that the ratio between carvacrol and chlorobromoisocyanuric acid affects the antibacterial effect on the sugarcane mosaic virus, the pathogen of corn dwarf mosaic disease. When the two are compounded at a weight ratio of 1: (1-15), the co-toxicity coefficient is greater than 120, which has a synergistic effect; and when the two are compounded at a weight ratio of 1: 5, the co-toxicity coefficient is as high as 174.6, which has a significant synergistic effect.

[0013] The second aspect of the present invention provides the use of the above-mentioned bactericidal composition in at least one of the following (1)-(3):

[0014] (1) Preparing an inhibitor of sugarcane mosaic virus;

[0015] (2) Prevent and control corn dwarf mosaic disease;

[0016] (3) Prepare products for preventing and treating corn dwarf mosaic disease.

[0017] The third aspect of the present invention provides an agent for preventing and treating corn dwarf mosaic disease, wherein the agent contains an effective amount of the above-mentioned fungicide composition.

[0018] Preferably, in the medicament, the weight percentage of the bactericidal composition is 5-80%.

[0019] Furthermore, the medicament also contains pharmaceutical excipients; optional pharmaceutical excipients include: adhesives, emulsifiers, dispersants, wetting agents, stabilizers, etc.

[0020] Furthermore, the dosage form of the drug can be granules, powders, suspensions, aqueous solutions, aqueous emulsions, sustained-release preparations, tablets, etc.

[0021] The fourth aspect of the present invention provides the use of the above-mentioned agent in the prevention and treatment of corn dwarf mosaic disease.

[0022] A fifth aspect of the present invention provides a method for preventing and treating corn dwarf mosaic disease, comprising the following steps:

[0023] Before or in the early stages of corn dwarf mosaic disease, spray the above-mentioned agent on the above-ground part of the corn plant.

[0024] Beneficial effects of the present invention:

[0025] The present invention found that the effect of carvacrol and chlorobromoisocyanuric acid mixed in preventing and controlling corn dwarf mosaic disease is significantly higher than that of a single component, and the synergistic effect is significant in the range of 1:1 to 1:15, among which 1:5 is the best ratio. It can reduce the dosage of the agent, improve the prevention and control effect, reduce the use cost, and improve the safety of crops and the environment. DETAILED DESCRIPTION

[0026] 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.

[0027] 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 embodiments. If the specific experimental conditions are not specified in the embodiments, they are usually in accordance with conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following embodiments and comparative examples, unless otherwise specified, can be obtained through commercial channels. Among them:

[0028] The CAS number of carvacrol is 499-75-2; the CAS number of chlorobromoisocyanuric acid is 89325-49-5. Sugarcane mosaic virus (SCMV) is recorded in the literature "Complete genome sequence analysis of two Shandong isolates of sugarcane mosaic virus", Acta Phytopathologica Sinica, 2016; it is isolate DWK1.

[0029] Example 1: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0030] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 10:1 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0031] Example 2: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0032] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 5:1 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0033] Example 3: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0034] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 1:1 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0035] Example 4: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0036] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 1:5 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0037] Example 5: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0038] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 1:10 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0039] Example 6: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0040] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 1:15 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0041] Example 7: Preparation of a fungicidal composition for preventing and controlling corn dwarf mosaic disease

[0042] Carvacrol and chlorobromoisocyanuric acid are mixed in a weight ratio of 1:20 to serve as a fungicide composition for preventing and controlling corn dwarf mosaic disease.

[0043] Application example: Indoor toxicity test of carvacrol and chlorobromoisocyanuric acid mixture against maize dwarf mosaic virus pathogen

[0044] 1. Test pathogen: Sugarcane mosaic virus (SCMV). Diseased corn leaves were collected from the field, isolated and identified, and then inoculated into healthy seedlings grown indoors. The diseased plants were used as the source of the test virus for indoor virulence determination.

[0045] 2. Test methods:

[0046] Refer to the "Guidelines for Indoor Bioassay Tests of Pesticides - Fungicides" Pot Plant Method (NY / T 1156.4-2006), "Methods for Research of Plant Diseases" and the Determination of the Combined Action of Fungicide Mixtures (NY / T 1156.6-2006).

[0047] Collect diseased leaves from virus-protected corn seedlings inoculated with the identified virus. Cut the diseased leaves into pieces and place them in a sterile mortar. Add 10 times the amount of diseased leaves in 0.1 mol / L phosphate buffer solution with a pH of 7.0, grind them at low temperature, and prepare an inoculation suspension.

[0048] One day before the corn seedlings were inoculated with the virus, the spray treatment was carried out using a quantitative spray tower. The single agent and the mixture of different proportions of the test agent were diluted into 5 concentrations according to the design requirements, and 30 corn seedlings were treated with each concentration, and repeated 4 times. After the drug treatment, the treated plants were placed in an artificial climate chamber at 20-26℃ for cultivation.

[0049] One day after the treatment, select healthy seedlings at the 4-5 leaf stage and inoculate the virus using the friction inoculation method. Before inoculation, spray an appropriate amount of 600-mesh corundum on the leaves of the inoculated plants, then use a cotton swab to dip a small amount of the prepared inoculation suspension, and gently rub the leaf surface to cause minor injuries. Inoculate 2 leaves per plant. The treatment without spraying the pesticide but only inoculating the virus is the blank control.

[0050] When the control seedlings are obviously diseased, check and record the disease level of each treatment according to the following standards:

[0051] Level 0: no disease;

[0052] Level 1: The lesion area accounts for less than 5% of the entire leaf area;

[0053] Level 3: The lesion area accounts for 6% to 15% of the entire leaf area;

[0054] Level 5: The lesion area accounts for 16% to 25% of the entire leaf area;

[0055] Level 7: The lesion area accounts for 26% to 50% of the entire leaf area;

[0056] Level 9: The lesion area accounts for more than 50% of the entire leaf area.

[0057] According to the investigated disease level, calculate the disease index and prevention effect of each treatment and take the average value.

[0058] Disease index = ∑ (number of diseased leaves at each level × relative level value) / (total number of leaves investigated × 9) × 100

[0059] Control effect (%) = (CK 1 -PT 1 ) / CK 1 ×100

[0060] Where: CK 1 -- Disease index of blank control area after application of pesticide;

[0061] PT 1 --Disease index in the area treated with pesticides after application.

[0062] Based on the survey data, calculate the disease index of each treatment, calculate the control effect of each treatment concentration according to the formula, and then use the DPS data processing software to calculate the test results, and respectively obtain the virulence regression equations, EC 50 and EC 90 as well as the 95% confidence limits of the single agent of the test agent and the mixed agent with different ratios, and calculate the co-toxicity coefficient (CTC) of different ratios of the two agents to screen out the optimal ratio of the test agent. And record the original data of all replicates of each treatment.

[0063] Corrected inhibition rate (%) = (spore germination rate of blank control - spore germination rate of treatment) / spore germination rate of blank control × 100

[0064] 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:

[0065] Actual toxicity index (ATI) = (EC 50 of standard agent / EC 50 of test agent) × 100

[0066] 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

[0067] Co-toxicity coefficient (CTC) = (ATI / TTI) × 100

[0068] According to the classification standard of the co-toxicity coefficient (CTC), CTC ≤ 80 is antagonistic effect, 80 < CTC < 120 is additive effect, and CTC ≥ 120 is synergistic effect.

[0069] 3. Test results:

[0070] The test results are shown in Table 1.

[0071] Table 1: Indoor combined toxicity determination results of carvacrol and chlorobromoisocyanuric acid against maize dwarf mosaic virus

[0072]

[0073] It can be seen from the results in Table 1 that both carvacrol and chlorobromoisocyanuric acid have good activities against maize dwarf mosaic virus, and the EC 50 are 12.4714 mg / L and 49.9842 mg / L respectively. The co-toxicity coefficient (CTC) is greater than 120 within the range of 1:1 to 1:15 for their ratio, showing a significant synergistic effect and high activity against maize dwarf mosaic virus. Among them, 1:5 is the optimal ratio.

[0074] In summary, the fungicidal composition of carvacrol and chlorobromoisocyanuric acid described in the present invention has a significant synergistic effect, can reduce the dosage of the agent, improve the effect of preventing and controlling corn dwarf mosaic disease, reduce the cost of use, and improve the safety to crops and the environment.

[0075] 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. A bactericidal composition, characterized in that: The composition is composed of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1:(1-15).

2. The bactericidal composition according to claim 1, characterized in that The bactericidal composition is composed of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1:(5-10).

3. The bactericidal composition according to claim 1 or 2, characterized in that The bactericidal composition consists of carvacrol and chlorobromoisocyanuric acid in a weight ratio of 1:

5.

4. Use of the bactericidal composition according to any one of claims 1 to 3 in at least one of the following (1) to (3): (1) Preparing an inhibitor of sugarcane mosaic virus; (2) Prevent and control corn dwarf mosaic disease; (3) Preparing products for preventing and treating corn dwarf mosaic disease.

5. A medicament for preventing and treating corn dwarf mosaic disease, characterized in that: The medicament contains an effective amount of the bactericidal composition according to any one of claims 1 to 3; in the medicament, the weight percentage of the bactericidal composition is 5-80%.

6. A method for preventing and treating corn dwarf mosaic disease, characterized in that: The following steps are involved: Before or at the early stage of the onset of corn dwarf mosaic disease, the agent of claim 5 is sprayed on the aerial part of the corn plant.

Images