A bactericidal composition for preventing and treating cucumber powdery mildew

Abstract

The present invention belongs to the technical field of pesticide R & D, and specifically relates to a bactericidal composition for preventing and controlling cucumber powdery mildew. A bactericidal composition for preventing and controlling cucumber powdery mildew, the active ingredients of which are composed of a binary compound of zinc pyrithione and azoxystrobin, cyflufenamid or flutriafol. The bactericidal composition of the present invention has a synergistic effect on cucumber powdery mildew, which can improve the control effect on cucumber powdery mildew, reduce the usage amount of chemical agents, and delay the generation rate of disease resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticide R & D, and particularly relates to a bactericidal composition for controlling cucumber powdery mildew. Background Art

[0002] Cucumber powdery mildew, also known as white disease and white mildew, is one of the important diseases of cucumbers, characterized by wide distribution, short incubation period, strong epidemicity and fast spread. It can occur from the seedling stage to the adult stage, mainly attacking the leaves, and can also attack the stems and petioles, generally not attacking the fruits. The cucumber powdery mildew pathogen (Sphaerotheca fuloginea (Schlecht) Poll.) is a fungus of the genus Sphaerotheca in the Ascomycotina subphylum, which can cause cucumber leaf diseases. The optimum temperature for disease occurrence is 16 - 25°C, and the disease occurs in large numbers when the air in the field is dry. With the continuous expansion of the vegetable cultivation area and scale, the occurrence area of cucumber powdery mildew is also increasing, and the degree is becoming more and more serious.

[0003] At present, there are mainly two directions for controlling cucumber powdery mildew: disease-resistant breeding and spraying chemical pesticides. Regarding disease-resistant breeding, due to the possible differences in the types of powdery mildew pathogens in different countries or different regions within the same country, and the complexity and variability of the pathogens themselves, it is difficult to effectively solve the occurrence of cucumber powdery mildew through disease-resistant breeding. In the actual production process, spraying chemical pesticides is still the main method. Chemical pesticides have the advantages of quick effect and stable effect. Common pesticides used for controlling cucumber powdery mildew include: difenoconazole, thiophanate-methyl, flusilazole, tricyclazole and azoxystrobin, etc. However, due to the short incubation time of the powdery mildew pathogen, fast spread with air currents and serious damage, and some growers' long-term and large-scale use of pesticides with the same action mechanism for control, the resistance of cucumber powdery mildew pathogens has developed relatively quickly, resulting in the decreasing control effect of various pesticides.

[0004] Developing new pesticides and compounding on the basis of existing pesticides can both deal with the emergence of resistance. However, developing new pesticides has high costs and a long cycle. Compounding on the basis of existing pesticides and screening compounding formulas with synergistic effects can not only reduce the usage amount of chemical agents, but also delay the speed of the emergence of disease resistance.

[0005] Zinc pyrithione, also known as ZPT, has strong bactericidal and inhibitory effects on fungi and bacteria. In the agricultural field, zinc pyrithione can be used as a green fungicide to control grape powdery mildew, strawberry powdery mildew, strawberry gray mold, etc.; in the field of ship coatings, zinc pyrithione can prevent microbial attachment and keep the hull smooth; in the daily chemical field, zinc pyrithione is an efficient antidandruff agent and is widely used in products such as shampoos and hair conditioners. The patent with the application number CN201010220094.5 discloses a fungicide containing ZPT and kresoxim-methyl, and specifically discloses that when ZPT and kresoxim-methyl are used in combination at a certain weight ratio, it can be used to control wheat powdery mildew, wheat scab, tomato gray mold, grape gray mold, grape powdery mildew and rice blast.

[0006] At present, there are no relevant reports on the compounding of zinc pyrithione with azoxystrobin, cyflufenamid or flutriafol. Summary of the Invention

[0007] The purpose of the present invention is to provide a bactericidal composition for controlling cucumber powdery mildew. Based on existing pesticides, a compounding formula with synergistic effects is screened, which can improve the control effect on cucumber powdery mildew, reduce the usage amount of chemical agents, and delay the generation speed of disease resistance.

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

[0009] A bactericidal composition for controlling cucumber powdery mildew, the active ingredient of which is composed of a binary compound of zinc pyrithione and azoxystrobin, cyflufenamid or flutriafol.

[0010] Preferably, the mass ratio of zinc pyrithione to azoxystrobin is 1-25:9-1.

[0011] Preferably, the mass ratio of zinc pyrithione to cyflufenamid is 1-16:30-1.

[0012] Preferably, the mass ratio of zinc pyrithione to flutriafol is 1-10:10-1.

[0013] Preferably, the mass ratio of zinc pyrithione to flutriafol is 7:1.

[0014] The present invention also provides a fungicide, which includes the above-mentioned bactericidal composition and agriculturally acceptable adjuvants.

[0015] The present invention also provides the use of the above-mentioned bactericidal composition or the above-mentioned fungicide for controlling cucumber fungal diseases.

[0016] Preferably, the cucumber fungal disease is cucumber powdery mildew.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The bactericidal composition of the present invention has a synergistic effect on cucumber powdery mildew, which can improve the control effect on cucumber powdery mildew, reduce the usage amount of chemical agents, and delay the generation speed of disease resistance to drugs. Detailed implementation manners

[0019] According to the following embodiments, the present invention can be better understood. However, those skilled in the art can easily understand that the content described in the embodiments is only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0020] Example : Indoor bioactivity test of the combination of zinc pyrithione

[0021] 1. Test strains: Sphaerotheca fuloginea (Schlecht) Poll. on cucumber

[0022] Use pure water containing 0.05% Tween-80 to wash the fresh spores on the cucumber leaves covered with powdery mildew, filter with double-layer gauze, and prepare a suspension of 1×10 5 spores / mL for standby;

[0023] 2. Test crops: Seedlings are raised in black plastic nutrient pots, with 2 "Beijing Xiaoci" cucumber seedlings planted in each pot, cultured until the 2 true leaf stage, and numbered for standby.

[0024] 3. Test agents

[0025] 98% zinc pyrithione technical, 97% azoxystrobin technical, 98% cyflufenamid technical, and 97% flutriafol technical. The above agents are all commercially available.

[0026] First dissolve the test agents with dimethyl sulfoxide, and then dilute them with 0.1% Tween-80 aqueous solution into single-agent mother liquors. Set multiple groups of ratios, and set 5 mass concentration gradients for each single agent and the mixed agents of the ratios according to the equal ratio method.

[0027] 4. Test method (refer to NY / T 1156.11-2008 "Pesticide indoor bioassay test guidelines Fungicides Part 11: Test potted plant method for controlling powdery mildew of cucurbits").

[0028] Spray inoculate the test crops with the spore suspension 24 h before the agent treatment; after natural air drying, evenly spray the liquid medicine on the leaves of the test crops until all are wet, with 5 pots for each treatment, 4 replicates, and set a treatment containing only 0.1% Tween-80 as the blank control; after natural air drying, move to a constant temperature room and continue to culture under the condition of a temperature of 25 °C; when the disease leaf rate of the blank control reaches more than 80%, investigate the disease incidence of each treatment, investigate 40 leaves for each treatment, and calculate the disease index and control effect of each treatment. Among them, the grading standard is shown in Table 1.

[0029] Table 1 Disease level assessment criteria

[0030]

[0031]

[0032]

[0033] 5. Data analysis: Use DPS software for data statistical analysis. Take the logarithm value of the fungicide concentration as x and the corresponding probit value of the control effect as y for linear regression to obtain the virulence regression equation and the virulence EC 50 value of the agent against the target pathogen, and calculate the co-toxicity coefficient (CTC) according to the Sun Yunpei method.

[0034]

[0035] In the above formula: ATI--measured virulence index of the mixture; S--LC of the standard agent 50 , unit: mg / L; M--LC of the mixture 50 , unit: mg / L.

[0036] TTI = TI A ×P A +TI B ×P B

[0037] In the above formula: TTI--theoretical toxicological index of the mixture; TI A --virulence index of agent A; P A --percentage content of agent A in the mixture, unit: percentage (%) ; TI B --virulence index of agent B; P B --percentage content of agent B in the mixture, unit: percentage (%).

[0038]

[0039] In the above formula: CTC--co-toxicity coefficient; ATI--measured virulence index of the mixture; TTI--theoretical virulence index of the mixture.

[0040] 6. Measurement Results

[0041] The synergistic effect of the agents was evaluated according to the calculated co-toxicity coefficient (CTC). When CTC ≤ 80, it indicates an antagonistic effect; when 80 < CTC < 120, it indicates an additive effect; when CTC ≥ 120, it indicates a synergistic effect. The results are shown in Table 2-4.

[0042] Table 2 Indoor Bioactivity Assay of the Compound of Zinc Pyrithione and Azoxystrobin against Podosphaera xanthii

[0043] Name and ratio of agents EC50 (mg / L) ATI TTI CTC Zinc pyrithione 8.77 100.00 -- -- Azoxystrobin 37.78 23.21 -- -- Zinc pyrithione 1: Azoxystrobin 9 22.76 38.53 30.89 124.73 Zinc pyrithione 1: Azoxystrobin 7 18.09 48.48 32.81 147.75 Zinc pyrithione 1: Azoxystrobin 3 12.78 68.62 42.41 161.81 Zinc pyrithione 1: Azoxystrobin 1 7.66 114.49 61.61 185.84 Zinc pyrithione 3: Azoxystrobin 1 4.13 212.35 80.80 262.80 Zinc pyrithione 7: Azoxystrobin 1 2.83 309.89 90.40 342.80 Zinc pyrithione 15: Azoxystrobin 1 5.27 166.41 95.20 174.80 Zinc pyrithione 25: Azoxystrobin 1 6.32 138.77 97.05 142.99

[0044] As can be seen from Table 2, after the compounding of zinc pyrithione and azoxystrobin, the co-toxicity coefficients against Podosphaera xanthii were all greater than 120 within the mass ratio range of 1-25:9-1, showing a synergistic effect.

[0045] Table 3 Indoor Bioactivity Assay of the Compound of Zinc Pyrithione and Cyflufenamid against Podosphaera xanthii

[0046]

[0047]

[0048] As can be seen from Table 3, after the compounding of zinc pyrithione and cyflufenamid, the co-toxicity coefficients against Podosphaera xanthii were all greater than 120 within the mass ratio range of 1-16:30-1, showing a synergistic effect.

[0049] Table 4 Indoor Bioactivity Assay of the Compound of Zinc Pyrithione and Flutriafol against Podosphaera xanthii

[0050] Name and ratio of agents EC50 (mg / L) ATI TTI CTC Zinc pyrithione 8.77 100.00 -- -- Flutriafol 13.24 66.24 -- -- Zinc pyrithione 1: Flutriafol 10 9.29 94.40 69.31 136.21 Zinc pyrithione 1: Flutriafol 7 8.11 108.14 70.46 153.48 Zinc pyrithione 1: Flutriafol 3 7.02 124.93 74.68 167.29 Zinc pyrithione 1: Flutriafol 1 4.73 185.41 83.12 223.07 Zinc pyrithione 3: Flutriafol 1 2.35 373.19 91.56 407.59 Zinc pyrithione 7: Flutriafol 1 1.27 690.55 95.78 720.98 Zinc pyrithione 10: Flutriafol 1 4.91 178.62 96.93 184.27

[0051] As can be seen from Table 4, after the compounding of zinc pyrithione and flutriafol, the co-toxicity coefficients against Podosphaera xanthii were all greater than 120 within the mass ratio range of 1-10:10-1, showing a synergistic effect; especially when the mass ratio was 7:1, the co-toxicity coefficient reached 720.98, and the synergistic effect was particularly significant.

[0052] In summary, after the compounding of zinc pyrithione with azoxystrobin, cyflufenamid or flutriafol, it has a good synergistic effect, which can improve the control effect against cucumber powdery mildew. Based on this, the usage amount of chemical agents can be reduced, the generation rate of disease resistance can be delayed, the control cost can be reduced, and the pesticide residue in cucumbers can be decreased.

[0053] The above description is only the preferred embodiment of the present invention. For those skilled in the art, without departing from the principle of the present invention, appropriate improvements can be made, and these improvements are also within the protection scope of the present invention.

Claims

1. A bactericidal composition for preventing and controlling cucumber powdery mildew, characterized in that, its active ingredients are composed of a binary compound of zinc pyrithione and azoxystrobin, and the mass ratio of zinc pyrithione to azoxystrobin is 1-25:9-1.

2. A bactericide, characterized in that, it comprises the bactericidal composition according to claim 1 and a pharmaceutically acceptable adjuvant.

3. Use of the bactericidal composition according to claim 1 or the bactericide according to claim 2 for preventing and controlling cucumber powdery mildew.

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