A bactericidal composition for preventing and treating wheat sheath blight

Abstract

The present invention belongs to the technical field of wheat sheath blight control, and specifically relates to a fungicide composition for controlling wheat sheath blight. The fungicide composition comprises a compound of gliotoxin and benzovindiflupyr or thiophanate-methyl. The present invention combines gliotoxins with different mechanisms of action and benzovindiflupyr or thiophanate-methyl in a specific mass ratio, exhibiting a synergistic fungicidal effect within a certain mass ratio range. The composition can be used to develop a highly effective fungicide for controlling wheat sheath blight.

Description

Technical Field

[0001] The invention belongs to the technical field of prevention and treatment of wheat sheath blight, and particularly relates to a fungicide composition for preventing and treating wheat sheath blight. Background Art

[0002] Gliotoxin (CAS: 67-99-2) is a cyclic diamino acid secondary metabolite extracted from the fermented mycelium of Trichoderma. It has inhibitory effects on many plant pathogenic fungi. Zhejiang University first discovered that gliotoxin has a significant preventive and control effect on rice sheath blight. Subsequent research has shown that gliotoxin has significant killing and inhibitory effects on soil-borne diseases.

[0003] Benzovindiflupyr and thiofluzamide are both succinate dehydrogenase inhibitor (SDHI) fungicides. They inhibit pathogen respiration by interfering with the tricarboxylic acid cycle on complex II of the respiratory electron transport chain, thereby inhibiting mitochondrial function, preventing energy production, inhibiting pathogen growth, and ultimately killing the pathogen. Benzovindiflupyr and thiofluzamide are systemic and have a long-lasting effect, making them useful for controlling a variety of crop diseases.

[0004] Wheat sheath blight, also known as wheat sharp eyespot, is a worldwide soil-borne fungal disease of wheat. Rhizoctonia cerealis ) and Rhizoctonia solani ( Rhizoctonia solani ) can cause wheat sheath blight. Although stable sources of resistance to wheat sheath blight have been obtained, resistant varieties are limited. In production, chemical control primarily relies on seed treatments with triadimefon, difenoconazole, and tebuconazole, combined with spring spraying. However, the widespread use of fungicides and their continuous application have reduced wheat sheath blight's sensitivity to various agents or led to varying degrees of resistance, resulting in a declining control effect.

[0005] Combining existing fungicidal active ingredients, particularly those with synergistic effects, can delay the development of bacterial resistance, improve efficacy, broaden the spectrum of activity, and reduce drug costs, making them an important tool for controlling crop diseases. However, there are no reports of fungicidal compositions containing gliotoxin combined with benzovindiflupyr or thiophanate-methyl for the control of wheat sheath blight.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] The object of the present invention is to provide a fungicide composition for preventing and treating wheat sheath blight, which can improve the prevention and treatment effect on wheat sheath blight and delay the development of drug resistance of pathogens.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A bactericidal composition is prepared by compounding gliotoxin with benzovinfluazide or thiophanate-methyl.

[0010] More specifically, the mass ratio of gliotoxin to benzovindiflupyr is 1-10:10-1.

[0011] More specifically, the mass ratio of gliotoxin to thiofuran is 1-3:20-1.

[0012] The present invention also provides a fungicide, which comprises auxiliary components and the fungicide composition.

[0013] Specifically, the auxiliary component is selected from one or more of a wetting agent, a dispersant, a disintegrant, an emulsifier, a solvent, an inert filler, a thickener, a defoaming agent and a preservative.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The present invention compounds gliotoxins with different mechanisms of action with benzovinflumazole or thiophanate-methyl in a certain mass ratio, and exhibits a synergistic bactericidal effect within a certain mass ratio range, which can be used to develop a highly effective fungicide for preventing and controlling wheat stripe blight.

[0016] (2) Compared with single benzovinflumizone or thiophanate-methyl, the fungicide composition of the present invention can improve the control effect of wheat sheath blight, thereby reducing the amount of drug used, alleviating environmental pollution, and improving safety. It can also reduce the risk of drug resistance in pathogens. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present invention.

[0018] Example :Screening of control agents

[0019] 1. Test strains

[0020] Wheat plants with typical symptoms of wheat sheath blight were collected and isolated, purified, and Koch's postulates were verified in the experiment. The pathogen was identified as Rhizoctonia graminearum ( Rhizoctonia cerealis ) and stored in PSA medium.

[0021] Inoculate Rhizoctonia graminearum into the center of the PSA culture medium, culture it at 25°C for 3 days, and set aside.

[0022] 2. Test agents

[0023] 98% Gliotoxin TC, 96% Benzovindiflupyr TC, 96% Thifluzamide TC

[0024] The test agent was completely dissolved in dimethyl sulfoxide and then diluted with 0.1% Tween-80 aqueous solution to form a single-dose stock solution. Multiple groups of ratios were set up, and each single-dose stock solution and the ratioed mixture were further diluted with 0.1% Tween-80 aqueous solution to set up 5 mass concentration gradients.

[0025] 3. Test methods

[0026] The mycelial growth rate method was used to determine the toxicity of single-dose stock solutions and proportioned mixtures to the test strain Rhizoctonia graminearum.

[0027] Mix 9 mL of pre-thawed PSA medium and 1 mL of the test agent in a sterile Erlenmeyer flask and pour into a 9 cm diameter Petri dish to prepare drug-containing plates of the corresponding concentration. Use the same volume of PSA plate containing 0.1% Tween-80 aqueous solution as a blank control. Five replicates are set up for each treatment. Use a microporator to cut a 5 mm diameter bacterial cake from the edge of the propagation colony of the test strain. Inoculate the center of the drug-containing plate and the blank control plate with the mycelium side facing down, with one cake per plate. Cover the plates and incubate in a 25°C incubator. When the blank control colonies reach approximately 6-7 cm in diameter, measure the diameter using the cross-hatch method, and calculate the inhibition rate of mycelial growth by different treatments.

[0028]

[0029] 4. Data Analysis

[0030] DPS software was used for data statistical analysis. The logarithmic value of fungicide concentration was taken as x and the corresponding probability value of mycelial growth inhibition rate was taken as y for linear regression. The virulence regression equation and the virulence EC value of the agent to the target pathogen were obtained. 50 The co-toxicity coefficient (CTC) was calculated according to the Sun Yunpei method.

[0031]

[0032] In the above formula: ATI --The measured toxicity index of the mixture; S --EC of standard medicine 50 , unit is mg / L; M --EC of the mixture 50 , unit is mg / L.

[0033]

[0034] In the above formula: TTI --Theoretical toxicological index of the mixture; TI A --Toxicity index of agent A; P A --The percentage of agent A in the mixture, in percentage (%); TI B --Toxicity index of agent B; P B --The percentage of agent B in the mixture, in percentage (%).

[0035]

[0036] In the above formula: CTC --Co-toxicity coefficient; ATI --Measured toxicity index of the mixture; TTI --Theoretical toxicity index of the mixture.

[0037] 5. Measurement Results

[0038] The synergistic effect of the agents was evaluated based on the calculated co-toxicity coefficient (CTC). CTC ≤ 80 indicated an antagonistic effect, 80 < CTC < 120 indicated an additive effect, and CTC ≥ 120 indicated a synergistic effect. The results are shown in Table 1-2.

[0039] Table 1 Indoor bioactivity test of gliotoxin and benzovinflumizone against wheat sheath blight pathogen

[0040] Drug name and ratio <![CDATA[EC 50 (mg / L)]]> ATI TTI CTC Gliotoxin 67.5916 100.0000 -- -- Benzovindiflupyr 8.0372 840.9844 -- -- Gliotoxin 1: Benzovindiflupyr 10 5.7645 1172.5492 773.6222 151.5661 Gliotoxin 1: Benzovindiflupyr 7 3.2457 2082.4968 748.3614 278.2742 Gliotoxin 1: Benzovindiflupyr 3 6.3641 1062.0763 655.7383 161.9665 Gliotoxin 1: Benzovindiflupyr 1 10.6003 637.6386 470.4922 135.5258 Gliotoxin 3: Benzovindiflupyr 1 18.9312 357.0381 285.2461 125.1684 Gliotoxin 7: Benzovindiflupyr 1 24.8496 272.0028 192.6231 141.2099 Gliotoxin 10: Benzovindiflupyr 1 33.1909 203.6450 167.3622 121.6792

[0041] As shown in Table 1, after the active ingredient gliotoxin is compounded with benzovinflumizone, the co-toxicity coefficient against wheat sheath blight pathogen is greater than 120 within the mass ratio range of 1-10:10-1, showing a synergistic effect.

[0042] Table 2 Indoor bioactivity test of gliotoxin and thiofuran against wheat sheath blight pathogen

[0043] Drug name and ratio <![CDATA[EC 50 (mg / L)]]> ATI TTI CTC Gliotoxin 67.5916 100.0000 -- -- Thifluzamide 1.3967 4839.3785 -- -- Gliotoxin 1: Thiofluzamide 20 1.2018 5624.1970 4613.6938 121.9023 Gliotoxin 1: Thiofluzamide 10 0.8951 7551.2904 4408.5259 171.2883 Gliotoxin 1: Thiofuramide 7 1.0918 6190.8408 4246.9562 145.7712 Gliotoxin 1: Thiofluzamide 3 1.1946 5658.0948 3654.5339 154.8240 Gliotoxin 1: Thiofuran 1 2.1475 3147.4552 2469.6893 127.4434 Gliotoxin 3: Thiofluzamide 1 4.2473 1591.4016 1284.8446 123.8595

[0044] As shown in Table 2, after the active ingredient gliotoxin is combined with thiophanate-methyl, the co-toxicity coefficient against wheat sheath blight pathogen is greater than 120 in the mass ratio range of 1-3:20-1, showing a synergistic effect.

[0045] In summary, the present invention combines gliotoxins with different mechanisms of action with benzovinflumixil or thiophanate-methyl in a certain mass ratio, exhibiting a synergistic fungicidal effect within a certain mass ratio range, and can be used to develop a highly effective fungicide for controlling wheat sheath blight. Furthermore, compared to single benzovinflumixil or thiophanate-methyl, the fungicidal composition of the present invention can improve the control effect against wheat sheath blight, thereby reducing the amount of drug used, alleviating environmental pollution, and improving safety. It can also reduce the risk of drug resistance in pathogens.

[0046] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A bactericidal composition, characterized in that The bactericidal composition is prepared by compounding gliotoxin and benzovindiflupyr, and the mass ratio of the gliotoxin to benzovindiflupyr is 1-10:10-1.

2. A fungicide, characterized in that: The bactericide comprises auxiliary components and the bactericidal composition according to claim 1.

3. The bactericide according to claim 2, characterized in that The auxiliary components are selected from one or more of wetting agents, dispersants, disintegrants, emulsifiers, solvents, inert fillers, thickeners, defoaming agents and preservatives.