A fungicidal composition for controlling papaya black spot

Abstract

The present application belongs to the technical field of disease prevention and treatment of papaya, and particularly relates to a fungicidal composition for preventing and treating papaya black spot disease. The fungicidal composition for preventing and treating papaya black spot disease is prepared by compounding flutianil with silthiopham or by compounding flutianil with benzene fluoro fungicide at a mass ratio of 1-200:200-1. The fungicidal composition of the present application is prepared by compounding flutianil with silthiopham or by compounding flutianil with benzene fluoro fungicide, which is different from the existing reported compounding formula and novel. Through indoor experimental research, it is found that the compounding formula shows a synergistic effect in inhibiting the growth of mycelium of the pathogenic fungus of papaya black spot disease, can improve the prevention and treatment effect on papaya black spot disease, in addition, the fungicidal composition of the present application is prepared by compounding two components, which can overcome the problem of single drug resistance to a certain extent, and can provide ideas for developing new high-efficiency fungicides.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of papaya diseases, and particularly relates to a fungicidal composition for preventing and treating papaya black spot. BACKGROUND

[0002] Papaya is a perennial fruit tree of the family Caricaceae, and is mainly produced in Guangdong, Guangxi Zhuang Autonomous Region, Hainan, Fujian and other places. The fruit contains various nutrients such as sugar, protein, carotene and lycopene, and has high health care function and edible value. Papaya black spot is a fungal disease on papaya, which mainly damages the fruit. Circular to elliptical brown lesions are formed, the lesions are slightly sunken, and gray to black mold-like substances are formed on the lesions, which seriously affects the commodity value of papaya.

[0003] In agricultural production, plant diseases are often prevented and controlled by using fungicides, of course, the prevention and control of papaya black spot is no exception. Fungicides have the advantages of application, fast effect, etc., and can quickly and effectively prevent and control target diseases. However, the fungicidal spectrum of single-component fungicides is limited, and due to the long-term unscientific use of single-component fungicides, the control objects develop resistance to them. With the accumulation of resistance, the control effect of fungicides is gradually reduced or even lost. Therefore, it is necessary to develop new high-efficiency fungicides for preventing and treating papaya black spot.

[0004] Compounding different fungicidal components is one of the effective and convenient ways to prevent and control drug-resistant diseases, and a reasonable compounding formula can not only improve the control effect on diseases, but also expand the fungicidal spectrum. However, not all compounding of different fungicidal components can achieve synergistic effect, so screening of compounding formula with synergistic effect on target has great significance for preventing and controlling diseases.

[0005] Flutianil is a piperidyl thiazole isoxazoline fungicide developed by DuPont (now Corteva) in the United States, with CAS registration number: 1003318-67-9, molecular formula: C 24 H 22 F5N5O2S. Flutianil has the effects of prevention, treatment and inhibition of spore production, has a unique action site on Oomycetes, and achieves fungicidal effect by inhibiting oxidation sterol binding protein (OSBP). The prior art has reported that flutianil can be compounded with kasugamycin, validamycin, polyoxin, metalaxyl-M, flutrimide, valinomycin, fluoroxydil, ethylicin, zhongshengmycin, fluazinam, fludioxonil, dimethomorph, carpropamid, famoxadone, enoxastrobin, pyraclostrobin and fluquinconazole, but there is no related report on the compounding of flutianil with silthiamic acid or the compounding of flutianil with benzene enantiomycin. SUMMARY

[0006] The present application aims to provide a fungicidal composition for preventing and treating papaya black spot disease, to solve the problem that the fungicidal spectrum of a single component fungicide is limited, and due to the long-term unscientific use of a single component fungicide, the prevention and treatment object develops drug resistance to the single component fungicide, and with the accumulation of drug resistance, the prevention and treatment effect of the fungicide gradually decreases and even fails.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0008] A fungicidal composition for preventing and treating papaya black spot disease, the active ingredients of the fungicidal composition are compounded by fluazinam and silthiopham, or by fluazinam and benzene fluoro fungicide in a mass ratio of 1-200:200-1.

[0009] As a preference, the mass ratio of fluazinam to silthiopham is 1-50:25-1.

[0010] As a preference, the mass ratio of fluazinam to silthiopham is 20:1.

[0011] As a preference, the mass ratio of fluazinam to benzene fluoro fungicide is 1-24:9-1.

[0012] A fungicide comprising the fungicidal composition, characterized in that the mass of the active ingredients of the fungicidal composition accounts for 1-45% of the total mass of the fungicide, and the rest is auxiliary ingredients.

[0013] As a preference, the auxiliary ingredients are selected from one or more of dispersants, wetting agents, disintegrants, binders, solvents, cosolvents, emulsifiers, synergists, antifoaming agents, pH regulators, preservatives, synergists and antifreezing agents.

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

[0015] The fungicidal composition of the present application is compounded by fluazinam and silthiopham, or by fluazinam and benzene fluoro fungicide, which is different from the existing reported compound formula, and is novel. Moreover, through indoor experimental research, it is found that the compound formula shows a synergistic effect in inhibiting the growth of papaya black spot disease pathogenic fungal hyphae, can improve the prevention and treatment effect on papaya black spot disease, in addition, the fungicidal composition of the present application is compounded by two components, which can overcome the problem of drug resistance of a single drug to a certain extent, and can provide ideas for the development of new high-efficiency fungicides. DETAILED DESCRIPTION

[0016] The technical solutions of the present application will be described below in a clear and complete manner.

[0017] Indoor test

[0018] 1. Test pathogen

[0019] The black spot disease samples of Carica papaya were collected, and the strains were obtained by tissue separation in the laboratory, and then single spore separation and purification was carried out. The pathogenic bacteria were identified as Alternaria alternata (Fr.) Keissl., which were preserved on PDA medium.

[0020] 2. Test agents

[0021] 95% flutianil, 98% silthiofam, 96% benthival

[0022] After the test agents were dissolved, they were diluted with 0.1% Tween-80 aqueous solution to 10,000 mg / L single agent stock solution. Multiple groups of ratios were set, and each single agent stock solution and the mixed agent of the ratios were set with 5 mass concentration gradients for standby.

[0023] 4. Agent treatment

[0024] The mycelial growth rate method was used. The PDA medium at 55°C and the agent solution were mixed in a sterile conical flask at a volume ratio of 9:1, and then poured into a culture dish (9 cm in diameter) after being shaken well, 10 mL of the mixed solution was poured into each dish. After cooling and solidification, a drug-containing plate was obtained. The treatment without the agent was set as a blank control, and 8 plates were set for each treatment. The pathogenic Alternaria alternata was activated and cultured on PDA medium at 28°C for 5 days. A puncher was used to take a 6 mm diameter fungus cake from the pathogenic colony, and the fungus cake was inoculated in the center of the drug-containing plate and the blank control plate. After covering the dish cover and placing it in a 28°C constant temperature incubator for 5 days, the colony diameter was measured by cross method, and the mycelial growth inhibition rate of different treatments was calculated.

[0025] D = D1-D2, wherein D is the colony growth diameter; D1 is the colony diameter; and D2 is the fungus cake diameter;

[0026] I = [(D0-D t ) ÷ D0] × 100, wherein I is the mycelial growth inhibition rate; D0 is the blank control colony growth diameter; and D t is the agent treatment colony growth diameter;

[0027] 5. Synergistic effect evaluation

[0028] Linear regression analysis was performed with the logarithmic value of the agent concentration as x and the corresponding mycelial growth inhibition rate probability value as y, and the EC 50 of each treatment agent was calculated. According to the method of Sun Yunpei, the co-toxicity coefficient (CTC value) of the mixed agent was calculated.

[0029] The synergistic effect of the mixed agents was evaluated according to the co-toxicity coefficient (CTC value), that is, CTC≤80 is antagonism, 80<CTC<120 is additive effect, and CTC≥120 is synergistic effect, and the results are shown in Tables 1-2.

[0030] Table 1 Indoor bioactivity determination of flutianil and silthiopham complex on alternaria alternata

[0031] Fungicide name and ratio LC 50 (mg / L) ATI TTI CTC flutianil 4.82 100.00 -- -- silthiofam 8.67 55.59 -- -- flutianil 1 : silthiofam 20 3.31 145.62 57.71 252.34 flutianil 1 : silthiofam 10 6.28 76.75 59.63 128.71 flutianil 1 : silthiofam 5 5.56 86.69 63.00 137.62 flutianil 1 : silthiofam 1 5.02 96.02 77.80 123.42 flutianil 5 : silthiofam 1 2.91 165.64 92.60 178.87 flutianil 10 : silthiofam 1 1.93 249.74 95.96 260.25 flutianil 20 : silthiofam 1 1.05 459.05 97.89 468.96 flutianil 50 : silthiofam 1 3.96 121.72 99.13 122.79

[0032] As shown in Table 1, the co-toxicity coefficients of flutianil and silthiopham in the mass ratio of 1-50:20-1 are all greater than 120, indicating that the bioactivity of flutianil and silthiopham complex on alternaria alternata can exhibit synergistic effect.

[0033] Table 2 Indoor bioactivity determination of flutianil and benzene fluoro fungicide complex on alternaria alternata

[0034] Fungicide name and ratio LC 50 (mg / L) ATI TTI CTC flutianil 4.82 100.00 -- -- metyltetrahydrophthalimide 12.15 39.67 -- -- flutianil 1 : metyltetrahydrophthalimide 9 8.77 54.96 45.70 120.25 flutianil 1 : metyltetrahydrophthalimide 3 4.41 109.30 54.75 199.62 flutianil 1 : metyltetrahydrophthalimide 1 4.89 98.57 69.84 141.14 flutianil 3 : metyltetrahydrophthalimide 1 3.65 132.05 84.92 155.51 flutianil 9 : metyltetrahydrophthalimide 1 1.78 270.79 93.97 288.17 flutianil 12 : metyltetrahydrophthalimide 1 3.03 159.08 95.36 166.82 flutianil 24 : metyltetrahydrophthalimide 1 2.55 189.02 97.59 193.69

[0035] As shown in Table 2, the co-toxicity coefficients of flutianil and benzene fluoro fungicide in the mass ratio of 1-24:9-1 are all greater than 120, indicating that the bioactivity of flutianil and benzene fluoro fungicide complex on alternaria alternata can exhibit synergistic effect.

[0036] In summary, the bactericidal composition of the present application is found by indoor experimental research that the complex formula exhibits synergistic effect on inhibiting the growth of the mycelium of the pathogenic fungus of papaya black spot disease, can improve the prevention and treatment effect on papaya black spot disease, in addition, the bactericidal composition of the present application is complexed by two components, which can overcome the problem of single agent resistance to a certain extent, and can provide ideas for developing new high-efficiency bactericides.

[0037] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications being suitable for specific applications and conditions. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. A fungicidal composition for preventing and controlling black spot disease in papaya, characterized in that, The active ingredient of the fungicidal composition is a mixture of flutianil and silthiofam at a mass ratio of 1-50:25-1.

2. The bactericidal composition according to claim 1, characterized by The mass ratio of flutianil to silthiofam is 20:

1.

3. A fungicide comprising the fungicidal composition of claim 1, characterized in that, In the fungicide, the mass of the active ingredient of the fungicidal composition accounts for 1-45% of the total mass of the fungicide, and the rest is auxiliary ingredients.

4. The sterilant of claim 3, wherein, The auxiliary ingredients are selected from one or more of dispersants, wetting agents, disintegrants, binders, solvents, cosolvents, emulsifiers, synergists, antifoaming agents, pH regulators, preservatives, synergists, and antifreezing agents.