A pesticide composition for preventing and treating tobacco brown spot disease

Abstract

The present invention belongs to the technical field of pesticides, and specifically relates to a pesticide composition for preventing and treating tobacco brown spot disease. A pesticide composition for preventing and treating tobacco brown spot disease, comprising a pesticide composition comprising a compound of zhongshengmycin and silthiopyrad, bixafen, or cyproconazole as active ingredients; the mass ratio of zhongshengmycin to silthiopyrad, bixafen, or cyproconazole being 1-100:100-1. When zhongshengmycin is compounded with silthiopyrad, bixafen, or cyproconazole in the pesticide composition of the present invention, it exhibits a synergistic effect in inhibiting the germination of tobacco brown spot disease spores, thereby improving the prevention and treatment effect of tobacco brown spot disease.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and particularly relates to a pesticide composition for preventing and treating tobacco brown spot disease. Background Art

[0002] Tobacco brown spot is a fungal leaf spot disease with rapid spread and a short incubation period, repeatedly infecting plants during the tobacco growing season. The pathogen that causes tobacco brown spot belongs to the deutero-fungi genus Alternaria. Currently, four known species of Alternaria are known to cause tobacco brown spot: Alternaria alternata, Alternaria longipes, Alternaria yaliinficiens, and Alternaria tenuissima. Tobacco brown spot is a major foliar disease affecting tobacco production and development in my country's tobacco-growing regions. When temperatures are favorable, it can spread rapidly over a wide area, causing leaf mutilation and an imbalance in internal chemical composition. This leads to poor quality and reduced utilization of tobacco leaves, severely impacting tobacco growth and quality, and often causing immeasurable losses to tobacco production.

[0003] Tobacco brown spot disease is currently primarily controlled through chemical control, with commonly used pesticides including sclerotinol, polyoxin, triadimefon, and pyraclostrobin. The long-term and extensive use of these chemicals has led to the development of resistance in tobacco brown spot pathogens, reducing their effectiveness. To effectively control the occurrence and prevalence of tobacco brown spot disease and slow the development of drug resistance in the pathogen, identifying new and highly effective pesticides for the disease is crucial.

[0004] Zhongshengmycin is an agricultural antibiotic developed by the Institute of Biocontrol of the Chinese Academy of Agricultural Sciences. Produced by the Hainan strain of Streptomyces lilacinus, it is an alkaline, water-soluble N-glycoside. Zhongshengmycin has a broad antimicrobial spectrum and is highly active against bacterial diseases of crops and some fungal diseases. It inhibits peptide bond formation in pathogenic bacterial proteins, leading to bacterial death. It also inhibits mycelial growth and spore germination, preventing and controlling fungal diseases.

[0005] In the prior art, Zhongshengmycin has been compounded with a variety of chemical agents, but there are no reports on the compounding of Zhongshengmycin with silthiopyrad, bixafen or cyproconazole.

[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 purpose of the present invention is to provide a pesticide composition for preventing and controlling tobacco brown spot disease, so as to solve the problem that long-term and large-scale use of chemical agents leads to drug resistance of tobacco brown spot disease bacteria, resulting in reduced control effect of chemical agents against it.

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

[0009] A pesticide composition for preventing and controlling tobacco brown spot disease, wherein the active ingredients are prepared by compounding zhongshengmycin with silthiopyrad, bixafen or cyproconazole; the mass ratio of zhongshengmycin to silthiopyrad, bixafen or cyproconazole is 1-100:100-1.

[0010] Preferably, the mass ratio of zhongshengmycin to silthiopyrad is 1-3:20-1.

[0011] Preferably, the mass ratio of Zhongshengmycin to Bixafen is 1-9:9-1.

[0012] Preferably, the mass ratio of Zhongshengmycin to cyproconazole is 1-15:15-1.

[0013] Preferably, the mass ratio of Zhongshengmycin to cyproconazole is 1:15.

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

[0015] (1) The mechanism of action of the present invention's Zhongshengmycin in killing pathogens is different from that of silthiopyrad, bixafen or cyproconazole, and can effectively delay the development of drug resistance in pathogens.

[0016] (2) When the Zhongshengmycin of the present invention is compounded with silthiopyrad, bixafen or cyproconazole, it exhibits a synergistic effect in inhibiting the germination of tobacco brown spot pathogen spores, thereby improving the control effect of tobacco brown spot pathogen. Based on this, the amount of pesticide used can be reduced, and pesticide residues can be reduced. 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 creative work are within the scope of protection of the present invention.

[0018] Spore germination test (Refer to "NY / T 1156.1-2006 Guidelines for Indoor Bioassay Tests of Pesticides - Fungicides Part 1: Test for Inhibition of Germination of Pathogenic Fungal Spores - Concave Slide Method").

[0019] 1. Preparation of spore suspension

[0020] Tobacco brown spot disease samples were collected from tobacco growing areas in Wuming District, Nanning City, Guangxi Zhuang Autonomous Region. The pathogen was isolated and purified in the laboratory, and identified as Alternaria alternata. The samples were then stored on PDA culture medium.

[0021] Tobacco brown spot pathogen was inoculated into "K236" flue-cured tobacco leaves at the 8-10 true leaf stage. After the pathogen produced spores, they were washed with sterile water, filtered, and centrifuged at 1000 rpm for 5 min. The supernatant was removed, deionized water was added, and centrifuged again. The spores were then resuspended in deionized water to 1×10 7 spores / mL, and added 0.5% glucose solution.

[0022] 2. Test agents

[0023] 96% zhongshengmycin powder, 98% silthiopyrad technical, 98% bixafen technical, 95% cyproconazole technical, all of the above agents are commercially available.

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

[0025] 3. Chemical treatment

[0026] Pipette 0.5 mL of the drug solution and 0.5 mL of the spore suspension into a test tube and mix thoroughly. Use a micropipette to pipette the mixture onto a concave glass slide. Place the slide in a Petri dish with a shallow layer of water, cover, and place in a 25°C incubator. Perform three replicates for each drug concentration, and include a 0.1% Tween-80 solution as a blank control.

[0027] 4. Experimental Investigation

[0028] When the spore germination rate of the blank control reached 90% or higher, spore germination was examined and processed. Four random fields of view were observed for each concentration of the drug solution, with a total of 200 spores counted. The number of germinations and the total number of spores were recorded, and the relative inhibition rate of spore germination was calculated for each treatment. Spores were considered to have germinated if the length of the germ tube was greater than the short radius of the spore.

[0029]

[0030]

[0031]

[0032] 5. Statistical Analysis

[0033] The EC of each agent was calculated by regression analysis based on the logarithmic value of each agent concentration and the corresponding relative inhibition rate of spore germination. 50 The co-toxicity coefficient (CTC) was calculated according to the Sun Yunpei method, and then the synergistic effect of the mixed use of drugs was evaluated based on the co-toxicity coefficient (CTC value). The results are shown in Table 1-3.

[0034] Table 1 Indoor bioactivity test of the combination of Zhongshengmycin and Sithiopyrad against tobacco brown spot pathogen Alternaria alternata

[0035] Drug name and ratio EC50(mg / L) ATI TTI CTC Zhongshengmycin 3.3097 100.0000 -- -- Silthiovax 8.7429 37.8559 -- -- Zhongshengmycin 1: Sithiopyrad 20 5.0948 64.9623 40.8151 159.1624 Zhongshengmycin 1: Sithiopyrad 10 6.1785 53.5680 43.5053 123.1298 Zhongshengmycin 1: Sithiopyrad 7 4.9314 67.1148 45.6239 147.1046 Zhongshengmycin 1: Sithiopyrad 3 3.1228 105.9850 53.3919 198.5039 Zhongshengmycin 1: Sithiopyrad 1 3.8620 85.6991 68.9279 124.3315 Zhongshengmycin 3: Sithiopyrad 1 2.7713 119.4277 84.4640 141.3949

[0036] As shown in Table 1, when Zhongshengmycin and silthiopyrad are combined within a mass ratio of 1-3:20-1, the co-toxicity coefficients of each combination for inhibiting the germination of tobacco brown spot pathogen Alternaria alternata spores are greater than 120, demonstrating a synergistic effect. This suggests that the combination of Zhongshengmycin and silthiopyrad can enhance the control of tobacco brown spot disease.

[0037] Table 2 Indoor bioactivity test of the combination of Zhongshengmycin and bixafen against tobacco brown spot pathogen Alternaria alternata

[0038] Drug name and ratio EC50(mg / L) ATI TTI CTC Zhongshengmycin 3.3097 100.0000 -- -- Bixafen 12.0974 27.3588 -- -- Zhongshengmycin 1: Bixafen 9 7.8579 42.1194 34.6229 121.6519 Zhongshengmycin 1: Bixafen 7 6.9072 47.9167 36.4389 131.4986 Zhongshengmycin 1: Bixafen 3 5.7963 57.1002 45.5191 125.4424 Zhongshengmycin 1: Bixafen 1 4.2461 77.9468 63.6794 122.4051 Zhongshengmycin 3: Bixafen 1 2.3507 140.7964 81.8397 172.0392 Zhongshengmycin 7: Bixafen 1 1.5212 217.5717 90.9198 239.3005 Zhongshengmycin 9: Bixafen 1 1.1489 288.0756 92.7359 310.6409

[0039] As shown in Table 2, when Zhongshengmycin and bixafen are combined within a mass ratio of 1-9:9-1, the co-toxicity coefficients of each combination for inhibiting the germination of tobacco brown spot pathogen Alternaria alternata spores are greater than 120, demonstrating a synergistic effect. This suggests that the combination of Zhongshengmycin and bixafen can enhance the control of tobacco brown spot disease.

[0040] Table 3 Indoor bioactivity test of the combination of Zhongshengmycin and cyproconazole against tobacco brown spot pathogen Alternaria alternata

[0041] Drug name and ratio EC50(mg / L) ATI TTI CTC Zhongshengmycin 3.3097 100.0000 -- -- Cyproconazole 2.7112 122.0751 -- -- Zhongshengmycin 1: Cyproconazole 15 0.3629 912.0143 120.6954 755.6330 Zhongshengmycin 1: Cyproconazole 7 0.9267 357.1490 119.3157 299.3311 Zhongshengmycin 1: Cyproconazole 3 1.8335 180.5127 116.5563 154.8716 Zhongshengmycin 1: Cyproconazole 1 2.4345 135.9499 111.0375 122.4360 Zhongshengmycin 3: Cyproconazole 1 1.7988 183.9949 105.5188 174.3717 Zhongshengmycin 7: Cyproconazole 1 2.0037 165.1794 102.7594 160.7439 Zhongshengmycin 15: Cyproconazole 1 2.5819 128.1885 101.3797 126.4440

[0042] Table 3 shows that when Zhongshengmycin and cyproconazole are combined in a mass ratio of 1-15:15-1, the co-toxicity coefficients for inhibiting spore germination of tobacco brown spot pathogen Alternaria alternata are greater than 120, demonstrating a synergistic effect. The co-toxicity coefficient is particularly high at a mass ratio of 1:15, and the synergistic effect is most pronounced. This suggests that combining Zhongshengmycin with cyproconazole can enhance the control of tobacco brown spot disease.

[0043] In summary, when the Zhongshengmycin of the present invention is compounded with silthiopyrad, bixafen or cyproconazole, it exhibits a synergistic effect in inhibiting the germination of tobacco brown spot pathogen spores, thereby improving the control effect of tobacco brown spot pathogen. Based on this, the amount of pesticide used can be reduced, and pesticide residues can be reduced.

[0044] 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 pesticide composition for preventing and treating tobacco brown spot disease, characterized in that: The active ingredient is prepared by compounding zhongshengmycin and silthiopyrad; the mass ratio of zhongshengmycin to silthiopyrad is 1-3:20-1.

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