A biocide and its application

Abstract

A first aspect of the present invention provides a biofungicide, the active ingredients of which are composed of glucan and oregano extract, with the mass ratio of the glucan to oregano extract being 1:10 to 2:1. The biofungicide of the present invention exhibits a synergistic effect when combined with the oregano extract, improving the biofungicide's efficacy against watermelon wilt and overcoming the drawback of chemical fungicides, which are prone to developing drug resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of fungicides, and in particular to a biological fungicide and application thereof. Background Art

[0002] Chemical control is the most widely used method in the integrated prevention and control of plant diseases and an effective means of urgently controlling the spread of diseases. However, the long-term use of chemical pesticides can cause plant pathogens to develop resistance to these chemicals. To achieve effective control, the use of chemical pesticides must be increased. However, high-dose chemical pesticides, in turn, damage the environment and endanger human and animal health, creating a vicious cycle. Therefore, the search for green biopesticides that are non-toxic or low-toxic, environmentally friendly, contain diverse active ingredients, and are less susceptible to resistance is of great significance.

[0003] Using plant extracts to control disease infestations is a pollution-free, environmentally friendly biological fungicide. However, the fungicidal effect of plant extracts used alone is not as good as that of chemical pesticides. Therefore, another agent is needed to improve its control effect.

[0004] Glucan is an elicitor of plant disease resistance and a newly developed bio-resistant virucide. It effectively inactivates viruses and has a strong control effect on a variety of viral diseases, but its use in fungal disease control is rarely reported.

[0005] Oregano, also known as Artemisia capillaris and small-leaved mint, is a perennial herb found on sunny hillside meadows, roadsides, and forest edges. It is distributed in Jiangsu, Zhejiang, Guangdong, Guizhou, Sichuan, Yunnan, Xinjiang, and Gansu. Oregano has a wide range of uses, serving as a valuable traditional Chinese medicine and spice. It is also used in agricultural pest control, though not extensively. Currently, there are no reports on the combination of glucan and oregano extract. Summary of the Invention

[0006] In view of the above-mentioned prior art, the purpose of the present invention is to provide a biocide and application thereof.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A first aspect of the present invention provides a biofungicide, wherein the active ingredients of the biofungicide are composed of glucan and oregano extract, and the mass ratio of the glucan to oregano extract is 1:10 to 2:1.

[0009] Preferably, the mass ratio of the glucan sugar to the oregano extract is 1:5.

[0010] Further, the oregano extract is obtained by the following method:

[0011] The whole oregano herb is dried to constant weight, crushed to 40 mesh size, placed in a round-bottom flask, and 6 times the volume of distilled water is added. Ultrasonication is performed for 1.5 hours at a power of 200W. The flask is connected to a volatile oil extractor, heated, maintained at a slight boil, and distilled for 3 hours to obtain an aqueous oregano extract. The residue of the aqueous oregano extract is added to 5 times the volume of 75% ethanol, ultrasonicated for 1 hour at a power of 200W. The flask is connected to a volatile oil extractor, heated, maintained at a slight boil, and distilled for 2 hours to obtain an alcoholic oregano extract. The aqueous and alcoholic extracts are combined and extracted multiple times with redistilled ether. The upper oil phase is collected in a stoppered test tube and dried over anhydrous sodium sulfate. Filter the filtrate, transfer it to a concentrator, and concentrate it by atmospheric distillation until the ether odor disappears. This yields the oregano extract.

[0012] Furthermore, the glucan sugar and oregano extract account for 1%-20% of the mass of the fungicide; the fungicide also includes auxiliary agents and fillers, the auxiliary agents account for 3%-12% of the mass of the fungicide, and the rest are fillers.

[0013] The second aspect of the present invention is to provide a use of the biofungicide in preventing and controlling crop diseases.

[0014] Furthermore, the crop disease is watermelon wilt.

[0015] Beneficial effects of the present invention:

[0016] In the biological fungicide of the present invention, the compound of glucan sugar and oregano extract exhibits synergistic effect, thereby improving the prevention effect of the agent on watermelon wilt disease and overcoming the disadvantage that chemical fungicides are prone to drug resistance. DETAILED DESCRIPTION

[0017] The technical solutions of the present invention are described below with reference to the following examples. However, the present invention is not limited to the following examples. The experimental methods and detection methods described in each example are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0018] 1. Test agent

[0019] Glucan: Purchased from Shandong Kailinong Biotechnology Co., Ltd., specification: 95% technical.

[0020] Oregano extract: Dry the whole oregano herb to constant weight, grind it to 40 mesh size, place it in a round-bottom flask, add 6 times the amount of distilled water, and sonicate for 1.5 hours at 200W. Connect the volatile oil extractor, heat, maintain a slight boil, and distill for 3 hours to obtain an aqueous oregano extract. Add 5 times the amount of 75% ethanol to the aqueous oregano extract residue, sonicate for 1 hour at 200W, connect the volatile oil extractor, heat, maintain a slight boil, and distill for 2 hours to obtain an alcoholic oregano extract. Combine the aqueous and alcoholic oregano extracts, extract multiple times with redistilled ether, and collect the upper oil phase into a stoppered test tube and dry over anhydrous sodium sulfate. Filter, transfer the filtrate to a concentrator, and concentrate by atmospheric distillation until the ether odor disappears. This yields the oregano extract.

[0021] The above-mentioned pharmaceutical agent dextran sugar was dissolved in distilled water, and the oregano extract was dissolved in acetone, and then diluted with 0.1% Tween-80 aqueous solution to prepare single-dose mother liquor and mother liquors of various mixed formulations. Five mass concentration gradients were set for each single dose and mixed formulation according to the equal ratio method.

[0022] 2. Test strains

[0023] The strain used in the experiment, Fusarium oxysporum f. sp. ni veum, was purchased from the China Industrial Microbiology Culture Collection Center with the collection number BNCC225899.

[0024] 3. Test methods

[0025] The mycelium growth rate method was used. A 0.5 cm bacterial block of watermelon wilt pathogen activated on PDA culture medium was punched out with a cork hole and inoculated into the center of PDA culture medium containing drugs of different concentrations, with the mycelium facing downward. The culture dish was covered with a lid and a drug-free control was set. Each treatment was repeated 3 times. The culture was placed in an incubator under the conditions of temperature of 26°C, relative humidity of 90%, and 12 h light and dark alternation (light intensity of 5000 Lux). When the diameter of the blank control colony grew to about 2 / 3 of the diameter of the culture dish, the colony diameter was measured by the cross method, and the inhibition rate of mycelium growth of different treatments was calculated.

[0026] Inhibition rate (%) = [(control colony diameter - treated colony diameter) × 100 /

[0027] (control colony diameter - inoculated cake diameter)]

[0028] 4. Data Analysis

[0029] Data analysis: Regression analysis was performed based on the logarithmic values ​​of each drug concentration and the corresponding inhibition rate probability values ​​to calculate the EC of each drug. 50The Wadley method was used to evaluate the interaction between the two agents. An SR of 0.5-1.5 indicates an additive effect between the two agents; an SR ≤ 0.5 indicates an antagonistic effect; and an SR ≥ 1.5 indicates a synergistic effect. The results of the experiments with glucanol and oregano extract are shown in Table 1.

[0030] EC 50 (Theoretical value) = (a + b) / (a ​​ / EC 50 a+b / EC 50 b);

[0031] SR=EC 50 (Theoretical value) / EC 50 (actual value);

[0032] Where SR is the synergistic coefficient, and a and b are the percentages of the components in the mixture.

[0033] The test results are shown in Table 1.

[0034] Table 1 Indoor toxicity results of the combination of glucan and oregano extract against watermelon wilt pathogen

[0035]

[0036]

[0037] As shown in Table 1, after the compounding of glucan sugar and oregano extract, in the mass ratio range of 1:10 to 2:1, it has an excellent inhibitory effect on the mycelial growth of watermelon wilt pathogen, and the SR is greater than 1.5, showing a synergistic effect. Especially when the mass ratio of glucan sugar and oregano extract is 1:5, the SR is 3.18, and the synergistic effect is significant, which improves the control effect of the agent on watermelon wilt disease.

[0038] The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various exemplary embodiments and various choices and changes of the present invention. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A biofungicide and its application, characterized in that: The active ingredients of the biofungicide are composed of glucan sugar and oregano extract, and the mass ratio of the glucan sugar to the oregano extract is 1:10 to 2:1; The oregano extract is obtained by the following method: taking the whole oregano herb, drying it to constant weight, crushing it to 40 mesh, placing it in a round-bottom flask, adding 6 times the amount of distilled water, ultrasonicating it for 1.5 hours at an ultrasonic power of 200W, connecting it to a volatile oil extractor, heating it, keeping it slightly boiling, and distilling it for 3 hours to obtain an oregano water extract; adding 5 times the amount of 75% ethanol to the oregano residue extracted with water, ultrasonicating it for 1 hour at an ultrasonic power of 200W, connecting it to a volatile oil extractor, heating it, keeping it slightly boiling, and distilling it for 2 hours to obtain an oregano alcohol extract; combining the oregano water extract and the oregano alcohol extract, extracting them multiple times with redistilled ether, taking the upper oil phase into a stoppered test tube, and drying it over anhydrous sodium sulfate; filtering, transferring the filtrate into a concentration bottle, and concentrating it by atmospheric distillation until there is no ether smell, thereby obtaining the oregano extract.

2. The biocide according to claim 1, characterized in that The mass ratio of the glucan sugar to the oregano extract is 1:

5.

3. The biofungicide according to claim 1, characterized in that The glucan sugar and oregano extract account for 1%-20% of the mass of the fungicide; the fungicide also includes auxiliary agents and fillers, the auxiliary agents account for 3%-12% of the mass of the fungicide, and the rest are fillers.

4. Use of the biofungicide according to any one of claims 1 to 3 in preventing and controlling crop diseases.

5. The use of the biofungicide in preventing and controlling crop diseases according to claim 4, characterized in that: The crop disease is watermelon wilt.

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