A fungicide composition for preventing and treating pitaya bacterial wilt

Abstract

The present application belongs to the technical field of pesticides, and particularly relates to a kind of fungicide composition for preventing and treating pitaya canker disease. The fungicide composition for preventing and treating pitaya canker disease is prepared by compounding effective components of nikkomycin, thiophanate-methyl, fluopicolide or metalaxyl in a mass ratio of 1-150:150-1. The fungicide composition is prepared by compounding two effective components with different action mechanisms, has obvious synergistic effect, and can improve the prevention and treatment effect on pitaya canker disease.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pesticides, and particularly relates to a fungicide composition for preventing and treating pitaya canker. BACKGROUND

[0002] Pitaya is a perennial tropical and subtropical fruit, which is rich in nutrients and unique functions, contains plant albumin and anthocyanins that are rarely found in general plants, and is rich in vitamins and water-soluble dietary fiber. In recent years, as the area of pitaya artificial planting is gradually expanded, pitaya diseases have also increased, and pitaya canker caused by Neoscytalidium dimidiatum is a common disease in pitaya planting in China. Pitaya canker starts from the tender stem, and the initial round-shaped concave greenish-yellow disease spot gradually turns into orange, and the stem and fruit are completely rotted in severe cases, resulting in a 20-30% yield reduction in the orchard, a severe yield reduction of up to 50%, or even no yield, and pitaya canker has gradually become a major disease in pitaya production.

[0003] Carbendazim, flusilazole, difenoconazole and thiophanate-methyl can be used to prevent and control pitaya canker, but due to long-term unreasonable use, the drug resistance of the pathogen is becoming increasingly serious, resulting in a decrease in the control effect. In addition, long-term unreasonable use of chemical pesticides to control pitaya canker also increases the control cost, causes environmental pollution and pesticide residue risks, and the like. Therefore, the research and development of new chemical pesticides with high efficiency, low toxicity and low residue is an important direction for future pesticide development.

[0004] Nicomycin is a nucleoside peptide antibiotic, which blocks the synthesis of chitin, a key element necessary for fungal cell wall, by inhibiting chitin synthase specific to fungi, causing swelling and rupture of fungal cells, and has a unique mechanism of action on fungi. Patent No. CN201310358167.0 discloses a pesticide composition containing tebuconazole and nicomycin, and specifically discloses that when tebuconazole and nicomycin are compounded in a certain mass ratio, they show obvious synergistic effect, which can reduce the dosage, thereby reducing the control cost and the pollution to the environment. Although tebuconazole and nicomycin related compounding formulations have been reported, but there is no related report on the compounding of nicomycin and thiophanate-methyl, fluopyram or metalaxyl.

[0005] The information disclosed in this section is intended only to increase the understanding of the general background of the present application, and should not be considered as admitting or implying in any form that the information constitutes prior art known to those skilled in the art. SUMMARY

[0006] The present application aims to provide a fungicide composition for preventing and treating pitaya bacterial wilt, which can improve the prevention and treatment effect on pitaya bacterial wilt, reduce the prevention and treatment cost, and also reduce the risk of environmental pollution and pesticide residues.

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

[0008] The present application provides a fungicide composition for preventing and treating pitaya bacterial wilt, wherein the effective components are composed of nikkomycin and thiophanate-methyl, fluopyram or metalaxyl in a mass ratio of 1-150:150-1.

[0009] Preferably, the mass ratio of nikkomycin and thiophanate-methyl is 1-6:16-1.

[0010] Preferably, the mass ratio of nikkomycin and fluopyram is 1-20:4-1.

[0011] Preferably, the mass ratio of nikkomycin and metalaxyl is 1-30:15-1.

[0012] The present application also provides a fungicide comprising the fungicide composition.

[0013] The present application also provides the application of the fungicide composition in preventing and treating pitaya bacterial wilt.

[0014] Preferably, the pathogenic bacteria of pitaya bacterial wilt is Neoscytalidium dimidiatum.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] (1) The fungicide composition of the present application is composed of two effective components with different action mechanisms, has obvious synergistic effect, can improve the prevention and treatment effect on pitaya bacterial wilt, and is also beneficial to overcome and delay the generation of drug resistance.

[0017] (2) The fungicide composition of the present application can reduce the dosage of effective components, reduce the prevention and treatment cost, reduce environmental pollution and pesticide residues, has good safety, and meets the safety requirements of pesticide preparation. DETAILED DESCRIPTION

[0018] The following clearly and completely describes the technical solutions of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0019] Example: Control agent screening

[0020] 1. Test strain

[0021] The pitaya wilt sample was collected, and the pathogen was isolated, purified, identified and pathogenicity tested in the laboratory. The obtained pathogen was Neoscytalidium dimidiatum, which was preserved on PDA medium.

[0022] 2. Test agent

[0023] 98% nicomycin raw drug, 98% thiophanate-methyl raw drug, 96% fluopyram raw drug, and 98% metalaxyl raw drug were all commercially available.

[0024] After the test agent was dissolved, it was diluted with 0.1% Tween-80 aqueous solution to prepare single-dose stock solutions. Multiple groups of ratios were set, and each single-dose stock solution and mixed agent were set with 5 mass concentration gradients by equal ratio method.

[0025] 3. Test method

[0026] The mycelial growth rate method was used. 9 mL of pre-melted PDA medium was added to a sterile conical flask, and 1 mL of drug solution was quantitatively taken from low concentration to high concentration and added to the above conical flask, respectively. After shaking well, it was poured into a culture dish with a diameter of 9 cm to prepare a drug-containing plate with the corresponding concentration; and a treatment without drug was set as a blank control, and 5 replicates were set for each treatment.

[0027] A 5mm diameter puncher was used to cut a fungus cake at the edge of the test strain colony, which was inoculated in the center of the drug-containing plate and the blank control plate, and then placed in a 28℃ constant temperature incubator for 2d. The colony diameter was measured by cross method, and the mycelial growth inhibition rate of different treatments was calculated.

[0028]

[0029] 4. Data analysis: The data were statistically analyzed by DPS software, the logarithmic value of fungicide concentration was taken as x, and the corresponding mycelial growth inhibition rate probability value was taken as y for linear regression, to obtain the virulence regression equation and the virulence EC 50 value of the agent to the target pathogen, and the co-toxicity coefficient (CTC) was calculated according to Sun Yunpei method.

[0030] 5. Determination results

[0031] According to the calculated co-toxicity coefficient (CTC), the synergistic effect of the agent was evaluated. CTC≤80 was antagonistic effect, 80<CTC<120 was additive effect, and CTC≥120 was synergistic effect. The results are shown in Tables 1-3.

[0032] Table 1 indoor biological activity of nicomycin and thiophanate-methyl compound on new dark column septate

[0033] Name of agent and ratio EC50 (mg / L) ATI TTI CTC Nikkomycin 9.6086 100.0000 -- -- Chlorothalonil 6.0773 158.1064 -- -- Nikkomycin 1 : Chlorothalonil 16 4.0870 235.1015 154.6884 151.9840 Nikkomycin 1 : Chlorothalonil 12 3.9005 246.3428 153.6367 160.3411 Nikkomycin 1 : Chlorothalonil 8 4.8863 196.6437 151.6501 129.6693 Nikkomycin 1 : Chlorothalonil 4 5.4230 177.1824 146.4851 120.9559 Nikkomycin 1 : Chlorothalonil 1 6.0136 159.7812 129.0532 123.8103 Nikkomycin 4 : Chlorothalonil 1 2.9645 324.1221 111.6213 290.3766 Nikkomycin 6 : Chlorothalonil 1 3.5190 273.0492 108.3009 252.1208

[0034] From table 1, after nicomycin and thiophanate-methyl compound, in the mass ratio of 1-6:16-1 range, the co-toxicity coefficient of new dark column septate is greater than 120, showing synergistic effect.

[0035] Table 2 indoor biological activity of nicomycin and fluopyram compound on new dark column septate

[0036]

[0037]

[0038] From table 2, after nicomycin and fluopyram compound, in the mass ratio of 1-20:4-1 range, the co-toxicity coefficient of new dark column septate is greater than 120, showing synergistic effect.

[0039] Table 3 indoor biological activity of nicomycin and metalaxyl compound on new dark column septate

[0040] Name of agent and ratio EC50 (mg / L) ATI TTI CTC Nikkomycin 9.6086 100.0000 -- -- Metalaxyl 4.4127 217.7488 -- -- Nikkomycin 1 : Metalaxyl 15 2.3757 404.4534 210.3895 192.2403 Nikkomycin 1 : Metalaxyl 10 3.7222 258.1430 207.0443 124.6801 Nikkomycin 1 : Metalaxyl 5 1.9631 489.4605 198.1240 247.0476 Nikkomycin 1 : Metalaxyl 1 4.9467 194.2426 158.8744 122.2618 Nikkomycin 5 : Metalaxyl 1 6.2004 154.9674 119.6248 129.5446 Nikkomycin 10 : Metalaxyl 1 6.7611 142.1159 110.7044 128.3742 Nikkomycin 20 : Metalaxyl 1 7.1892 133.6533 105.6071 126.5571 Nikkomycin 30 : Metalaxyl 1 5.7941 165.8342 103.7983 159.7658

[0041] From table 3, after nicomycin and metalaxyl compound, in the mass ratio of 1-30:15-1 range, the co-toxicity coefficient of new dark column septate is greater than 120, showing synergistic effect.

[0042] In summary, the co-toxicity coefficient of the pathogenic fungus of pitaya wilt disease new dark column septate Neoscytalidium dimidiatum in the fungicidal composition of the application is greater than 120 when nicomycin is compounded with thiophanate-methyl, fluopyram or metalaxyl, and the synergistic effect is obvious, which can improve the control effect on pitaya wilt disease, and is also beneficial to overcome and delay the generation of drug resistance.

[0043] 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 suited to the particular use contemplated. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. A fungicide composition for preventing and treating dragon fruit canker, characterized in that, Its active ingredient is a compound of nicotinic acid and thiophanate-methyl, wherein the mass ratio of nicotinic acid to thiophanate-methyl is 1-6:16-1.

2. A bactericide, characterized in that, Includes the bactericidal composition according to claim 1.

3. The application of the fungicide composition according to claim 1 in the prevention and control of dragon fruit canker, characterized in that, The pathogen causing the dragon fruit canker disease is *Normacea micrantha*. Neoscytalidium dimidiatum .

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