A method for preparing a medicine for preventing and controlling corn diseases using corn stalks

Abstract

The present invention discloses a method for preparing a medicament for preventing and controlling corn diseases using corn straw, belonging to the field of agricultural biotechnology. Dry, mildew-free corn straw is selected, pulverized, added to a solvent, ultrasonically treated, a precipitant is added, ice-bathed, filtered, concentrated, dispersed with water, the pH value is adjusted, and a stabilizer is added to prepare a medicament prepared using corn straw. Corn straw, as an agricultural waste, is widely available and easily accessible. Using corn straw to prepare medicaments can reduce dependence on limited natural resources. Compared with the prior art that often uses pesticides for disease prevention and control, the present invention provides a more environmentally friendly alternative. Corn straw contains rich bioactive ingredients, such as flavonoids and alkaloids, which have various biological activities such as antibacterial, antioxidant, and antiviral. Through a specific preparation process, these active ingredients can be extracted and retained, thereby preparing a medicament with the function of preventing and controlling corn diseases.

Description

Technical Field

[0001] The invention belongs to the field of agricultural biotechnology, and in particular relates to a method for preparing a medicament for preventing and controlling corn diseases by utilizing corn stalks. Background Art

[0002] Corn not only plays an important role as a raw material in the light industry and pharmaceutical industry, but is also an indispensable export agricultural product and feed crop in foreign trade and the animal husbandry industry.

[0003] However, the damage caused by northern corn leaf blight poses a serious challenge to corn cultivation and production, especially in the spring-sown corn region of Northeast China, where it is one of the most important diseases. Northern corn leaf blight occurs throughout the corn growth period, but is generally more severe in the middle and late stages of growth, especially after the tasseling stage.

[0004] After the large leaf spot fungus infects corn leaves, the lesions expand rapidly along the veins and are not restricted by the veins. They soon form large, long, spindle-shaped lesions with gray-brown centers. The general size is (50-100) × (8-15) (mm), and some can reach 200mm in length. When the disease is severe, the lesions often merge and become connected, causing the leaves to dry up, seriously affecting the yield and quality of corn. The yield loss of susceptible varieties can reach more than 30%.

[0005] The primary source of infection for northern leaf spot disease is diseased corn stalks left in the fields after the previous year's harvest, left in the field without fully decomposing them. The following spring, under favorable temperature and humidity conditions, the overwintering mycelium in the diseased stalks produces large numbers of conidia. These conidia are then spread to healthy corn leaves by natural forces like air currents and rain, triggering the initial infection.

[0006] Currently, the use of chemical agents remains the most common means of field control of corn leaf blight. Agents such as difenoconazole, azoxystrobin, propiconazole-ammonia-methyl, and tebuconazole-ammonia-methyl are widely used. However, the rapid mutation rate of the pathogen, coupled with long-term drug use, reduces its sensitivity to conventional agents, leading to resistance. Moreover, excessive chemical residues can cause irreversible damage to field ecosystems, violating the environmental protection concept of green control and integrated management. Therefore, exploring more efficient and environmentally friendly strategies for corn leaf blight control that reduce reliance on chemical agents has become an urgent issue in this field. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preparing a pesticide for preventing and controlling corn diseases using corn stalks, so as to solve the problems existing in the above-mentioned prior art.

[0008] One of the technical solutions provided by the present invention:

[0009] A preparation method of a medicine prepared by using corn straw comprises the following steps: selecting dry and mildew-free corn straw, crushing the corn straw, adding the resulting mixture into a solvent, performing ultrasonic treatment, adding a precipitant, ice bathing the resulting mixture, filtering, concentrating, dispersing the resulting mixture with water, adjusting the pH, and adding a stabilizer to prepare the medicine prepared by using corn straw.

[0010] The solvent is an ethanol aqueous solution.

[0011] The temperature of the ultrasonic treatment is 40-60° C., the time is 1-3 hours, and the power is 100-300W.

[0012] The precipitant is polyethylene glycol.

[0013] The added amount of the polyethylene glycol (PEG) is 2-5% of the mass of the corn straw.

[0014] The pH is 5-7.

[0015] The amount of the stabilizer added is 1-2% of the mass of the concentrated product.

[0016] Corn straw, a major agricultural waste product after corn harvest, is rich in bioactive components such as polyphenols, flavonoids, and alkaloids, which have potential antibacterial and antiviral activities. However, research on the application of corn straw in biopesticides is limited, and technical solutions for its efficient extraction and utilization are lacking. Although polyphenols have antibacterial and antiviral properties, the effectiveness and safety of phenols in corn straw for direct use in corn disease prevention and control have not been fully verified. Furthermore, phenolic compounds are often considered harmful byproducts, and measures are needed to reduce their harm to crops. PEG has a strong affinity for phenols, which facilitates the precipitation of polyphenols. After adding PEG, the extract is treated in an ice bath to bind and precipitate the polyphenols, retaining the flavonoids and alkaloids in the filtrate. The ethanol in the solvent is then removed by concentration to obtain an extract containing flavonoids and alkaloids. Flavonoids and alkaloids are relatively unstable in water, so the addition of stabilizers such as sodium alginate or mannitol improves their dispersion stability in the formulation.

[0017] The second technical solution provided by the present invention is:

[0018] A medicine prepared by using corn stalks is prepared by the above-mentioned preparation method.

[0019] The third technical solution provided by the present invention is:

[0020] An application of the above-mentioned agent prepared using corn stalks in preventing and controlling corn diseases.

[0021] The corn disease is the disease of southern corn leaf blight.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] Corn stalks are agricultural waste that is widely available and easy to obtain. Using corn stalks to prepare pesticides can reduce dependence on limited natural resources. Compared with the existing technology that often uses pesticides for disease prevention and control, the present invention provides a more environmentally friendly alternative. Corn stalks are rich in bioactive ingredients, such as flavonoids, alkaloids, etc. These ingredients have multiple biological activities such as antibacterial, antioxidant and antiviral. Through a specific preparation process, these active ingredients can be extracted and retained to prepare a pesticide with the function of preventing and controlling corn diseases. In addition to preventing and controlling diseases, the pesticides prepared from corn stalks may also have functions such as promoting crop growth and improving crop stress resistance. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The embodiment of the present invention provides a preparation method of a medicine prepared by using corn straw, comprising the following steps: selecting dry and mildew-free corn straw, crushing it, adding it to a solvent, performing ultrasonic treatment, adding a precipitant, ice bathing it, filtering, concentrating, dispersing it with water, adjusting the pH, and adding a stabilizer to prepare the medicine prepared by using corn straw.

[0030] In some embodiments of the present invention, the solvent is an ethanol aqueous solution.

[0031] In some embodiments of the present invention, the ultrasonic treatment temperature is 40-60° C., the time is 1-3 h, and the power is 100-300 W. For example, in the following preferred embodiments of the present invention, the ultrasonic treatment temperature is 40° C., 50° C., 60° C., or any range therebetween; the ultrasonic treatment time is 1 h, 2 h, 3 h, or any range therebetween; and the ultrasonic treatment power is 100 W, 200 W, 300 W, or any range therebetween.

[0032] In some embodiments of the present invention, the precipitant is polyethylene glycol.

[0033] In some embodiments of the present invention, the amount of polyethylene glycol added is 2-5% by weight of the corn stalk. For example, in the following preferred embodiments of the present invention, the amount of polyethylene glycol added is 2.5%, 4%, 5% by weight of the corn stalk, or any range therebetween.

[0034] In some embodiments of the present invention, the pH is 5-7. Exemplarily, in the following preferred embodiments of the present invention, the pH is 5, 6, 7, or any range between the aforementioned ratios.

[0035] In some embodiments of the present invention, the stabilizer is selected from sodium alginate or mannitol. Exemplarily, in the following preferred embodiments of the present invention, the stabilizer is selected from sodium alginate.

[0036] In some embodiments of the present invention, the stabilizer is 1-2% of the mass of the concentrated product. Exemplarily, in the following preferred embodiments of the present invention, the stabilizer is 1%, 1.3%, 2% of the mass of the concentrated product, or any range between the foregoing proportions.

[0037] An embodiment of the present invention provides a medicament prepared using corn stalks and obtained by the above-mentioned preparation method.

[0038] The embodiment of the present invention provides the use of a medicament prepared using the above-mentioned corn stalks in preventing and controlling corn diseases, wherein the corn disease is corn leaf blight.

[0039] It should be noted that the parts not described in detail in the embodiments of the present invention can be achieved by conventional means in the art, such as ice bath treatment, rotary evaporation concentration and preparation of corn leaf blight spore suspension.

[0040] Except for corn stalks, all the raw materials required for the examples of the present invention were purchased commercially, among which polyethylene glycol-8000 powder was purchased from Shanghai Donghui Chemical Technology Co., Ltd.; sodium alginate was purchased from Zhengzhou Kangyuan Chemical Products Co., Ltd.

[0041] Example 1

[0042] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200W, 2h), 25 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and sodium alginate was added in an amount of 1% by mass of the solid powder to prepare a pharmaceutical agent prepared using corn stalks.

[0043] Example 2

[0044] 1 kg of dry, mildew-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (100W, 3 h), 50 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), the pH was adjusted to 7 with a phosphate buffer solution, and sodium alginate was added in an amount of 2% by mass of the solid powder to prepare a pharmaceutical agent prepared using corn stalks.

[0045] Example 3

[0046] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 60° C. (300 W, 1 h), 40 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h. The mixture was filtered and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), the pH was adjusted to 6 with a phosphate buffer solution, and sodium alginate was added in an amount of 1.3% by mass of the solid powder to prepare a pharmaceutical agent prepared using corn stalks.

[0047] Comparative Example 1

[0048] Same as Example 1, except that polyethylene glycol was not added. The specific operation was as follows:

[0049] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200W, 2 h), and treated in an ice bath for 0.5 h. The resulting mixture was filtered and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and sodium alginate (1% by mass of the solid powder) was added to prepare a pharmaceutical agent prepared using corn stalks.

[0050] Comparative Example 2

[0051] Same as Example 1, except that an excess of polyethylene glycol was added. The specific operation was as follows:

[0052] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200W, 2 h), 80 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and sodium alginate was added in an amount of 1% by mass of the solid powder to prepare a pharmaceutical agent prepared using corn stalks.

[0053] Experiment on soaking seeds of hydroponic corn

[0054] The corn variety for testing is Tieyan 368. 450 healthy, disease-free, similar-shaped and full-grained corn seeds are selected and placed in 50 ± 5 ° C of pure water to soak for 20 min. They are then immersed in a medicament solution (each medicament is diluted 5 times with water) and a clear water control solution prepared in advance by Example 1-3 and Comparative Example 1-2 for 15 h. 75 corn seeds are processed for each treatment. The soaked corn seeds are taken out completely and laid flat on a filter paper-lined bottom glass culture dish with a diameter of 20 cm. 25 of each dish are repeated 3 times in each group. Cultivated in a light culture chamber at room temperature of 25 ± 2 ° C, humidity of 45 ± 5%, and 12 h of light and dark alternation. After spraying water once every 24 h, humidity is maintained by sealing with a transparent film. The film can be removed when the corn seedling plant height exceeds the culture dish height. Other management conditions remain consistent.

[0055] Determination indicators: The germination rate was measured on the 3rd day of corn seed culture; the number of lateral roots and root length were measured on the 7th day; the plant height was measured on the 10th day; and the superoxide dismutase (SOD) activity in the corn seedlings was measured on the 12th day. The determination results are shown in Table 1.

[0056] Table 1

[0057]

[0058]

[0059] Note: Germination rate (%) = total number of germinations / total number of seeds × 100

[0060] Table 1 shows that the corn stalk-based formulation prepared according to the present invention significantly improves germination and seedling growth. Comparative Example 1, due to the absence of polyethylene glycol, contains a certain amount of polyphenols in the formulation, which inhibits seed germination and seedling growth. Adding an excessive amount of polyethylene glycol results in oversaturation, causing the polyethylene glycol to aggregate and precipitate. This precipitation process also removes the extracted flavonoids and alkaloids, reducing the effective components in the formulation and thus affecting germination and seedling growth.

[0061] SOD enzyme is often regarded as a protective enzyme or an inducible enzyme. SOD enzyme can eliminate O2 - , effectively slowing down and preventing the peroxidation process of membrane lipids, ensuring the integrity of cell membranes, and thus achieving the purpose of improving the plant's stress resistance. From the test results, it can be seen that when the agent prepared by the present invention is used for soaking, the SOD enzyme activity in the corn seedlings is significantly higher than that of the control example and clean water, indicating that the agent prepared by the present invention has a strong adverse stress effect on the corn seedlings after treatment, and the corn seedlings may enhance their resistance to adversity through SOD enzyme activity.

[0062] Field test on the efficacy of pesticides against corn leaf spot

[0063] The preparation of corn leaf blight spore suspension using the corn leaf blight strain (isolated and identified by the Institute of Plant Protection, Liaoning Academy of Agricultural Sciences) was carried out at our experimental station in the autumn of 2022. The susceptible corn germplasm material used for the test was Liao 3162.

[0064] When the corn had grown to 6-7 leaves, the agents of Examples 1-3 and Comparative Examples 1-2 were evenly sprayed on the surface of the corn leaves. The control was treated with an equal amount of water. 2 days later, at 6-7 pm, the previously prepared corn leaf blight spore suspension (1×10 4 10 mL / mL) was evenly sprayed on the corn leaves, repeated multiple times, with each plant spraying approximately 10 mL, and continued for 3 days, spraying twice a day in the morning and evening to keep it moist. 20 days after inoculation with the corn leaf blight pathogen, 10 corn plants in the treatment plot were randomly surveyed and the disease status of the corn leaves was recorded. The disease level was determined according to the corn leaf blight disease level grading standard in Table 2. Table 3 shows the disease results of Examples 1-3, Comparative Examples 1-2, and clean water.

[0065] Table 2

[0066]

[0067] Table 3

[0068] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 clear water level Level 3 Level 3 Level 3 Level 4 Level 4 Level 5

[0069] It can be seen from Table 2 and Table 3 that, compared with spraying with clean water, the agent prepared by the present invention can effectively prevent and control corn leaf blight, providing a new prevention and control measure for the prevention and control of corn diseases.

[0070] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a medicine using corn stalks, characterized in that: The following steps are involved: Dry, mildew-free corn stalks are selected, pulverized, added to a solvent, ultrasonically treated, a precipitant is added, ice-bathed, and filtered. The filtrate is concentrated, and the solid powder obtained by the concentration is dispersed with water, the pH is adjusted, and a stabilizer is added to prepare a pharmaceutical agent prepared using corn stalks. The solvent is an ethanol aqueous solution with a volume ratio of ethanol to water of 2:8; The precipitant is polyethylene glycol-8000.

2. The preparation method according to claim 1, characterized in that The temperature of the ultrasonic treatment is 40-60° C., the time is 1-3 hours, and the power is 100-300W.

3. The preparation method according to claim 1, characterized in that The added amount of polyethylene glycol-8000 is 2-5% of the mass of the corn straw.

4. The preparation method according to claim 1, characterized in that The stabilizer is selected from sodium alginate or mannitol.

5. The preparation method according to claim 4, characterized in that The amount of the stabilizer added is 1-2% of the mass of the concentrated product.

6. A medicine prepared using corn stalks, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the medicament prepared using corn stalks according to claim 6 in preventing and controlling corn diseases.

8. The application according to claim 7, characterized in that: The corn disease is the disease of southern corn leaf blight.

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