A composition for controlling bacterial leaf streak of rice and a preparation method thereof

Abstract

The application provides a composition for preventing and treating bacterial leaf streak of rice and a preparation method thereof, and relates to the technical field of agriculture.The composition is composed of the following components in a mass ratio: ramie extract: camphor tree leaf extract = 5-8:1-2;wherein the ramie extract is obtained by adjusting the alcohol content of a ramie water extract solution to 25-35%, discarding the precipitate, then adjusting the alcohol content of the ramie water extract solution to 50-55% again, and collecting and drying the precipitate; and the camphor tree leaf extract is obtained by fermenting camphor tree leaves with papain.The composition effectively improves the current situation that the prevention and treatment effect of existing chemical agents on bacterial leaf streak of rice is not ideal, and has the remarkable characteristics of being economical, environmentally friendly, and excellent in prevention and treatment effect, and has important positive significance for promoting the prevention and treatment of bacterial leaf streak of rice.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to a composition for controlling bacterial leaf streak disease of rice and its preparation method. Background Technology

[0002] Bacterial leaf streak of rice, also known as fine streak or stripe disease, primarily affects the leaves and is one of the most rapidly infective diseases in rice production, classified as a quarantine disease of agricultural plants. It is the fourth most prevalent rice disease after rice blast, sheath blight, and bacterial leaf blight. The disease mainly enters through leaf stomata and wounds, forming streaks on the leaves. High temperature and humidity conditions favor its development, especially during the rainy season, which greatly facilitates its spread.

[0003] With the increase in rice planting area and the promotion of hybrid rice, the incidence of bacterial leaf streak has been rising year by year, exhibiting characteristics of epidemicity and outbreaks. This disease can reduce rice yield by 15%-25%, and in severe cases, by 40%-60%, or even lead to complete crop failure. To date, the control efficacy of chemical agents (such as widely used copper-based agents) for bacterial leaf streak is not very ideal.

[0004] The occurrence of bacterial leaf streak in rice can severely damage agricultural efficiency. In order to ensure rice yield and quality, it is necessary to strengthen the prevention and control of bacterial leaf streak in rice. Summary of the Invention

[0005] The purpose of this invention is to provide a composition for the prevention and control of bacterial leaf streak in rice and its preparation method, so as to solve the problems existing in the prior art and achieve effective prevention and control of bacterial leaf streak in rice by naturally extracted substances.

[0006] Existing research has shown that the active ingredients in natural plants are low in toxicity, highly effective, and environmentally friendly. Extracting effective substances from natural plants and finding extracts with specific efficacy has become a hot topic in green agriculture research. This invention addresses the shortcomings of existing chemical reagents in controlling bacterial leaf streak in rice, which are not ideal in terms of control efficacy and fail to meet green and environmental protection requirements. It develops a composition extracted from natural plants, which demonstrates excellent efficacy in controlling bacterial leaf streak in rice.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a composition for controlling bacterial leaf streak in rice, the composition comprising the following components in the following mass ratio: ramie extract: camphor leaf extract = 5-8: 1-2; Camphor tree leaves have various medicinal properties, including insect repellent, antibacterial, and heat-clearing and detoxifying effects, playing an important role in many fields. Ramie is also a natural plant with antibacterial potential. This invention focuses on the extraction of natural substances. The ramie extract is obtained by adjusting the alcohol content of a ramie aqueous extract solution to 25-35%, discarding the precipitate, then adjusting the alcohol content again to 50-55%, collecting the precipitate, and drying it. The camphor tree leaf extract is obtained by fermenting camphor tree leaves with papain.

[0008] As a further preferred embodiment of the present invention, the ratio of ramie extract to camphor leaf extract is 7:2.

[0009] As a further preferred embodiment of the present invention, the fermentation temperature is 25-27°C.

[0010] The present invention further provides a method for preparing the above-mentioned composition for controlling bacterial leaf streak of rice, comprising the following steps: Preparation of ramie extract: Ramie is crushed and mixed with water. Then, a pressure of 155-165 MPa is applied to the resulting mixture. The mixture is then filtered and the filtrate is collected. The alcohol content of the filtrate is adjusted to 25-35%, and the precipitate is discarded. The alcohol content is then further adjusted to 50-55%. The mixture is allowed to stand, filtered, and the precipitate is collected and dried to obtain the ramie extract. Preparation of camphor tree leaf extract: Camphor tree leaves are mixed with water, then papain is added for enzymatic hydrolysis, enzyme inactivation is performed, the filtrate is collected by filtration, and then the filtrate is concentrated and dried to obtain the camphor tree leaf extract. The ramie extract and the camphor tree leaf extract are mixed in a certain mass ratio to obtain the composition for controlling bacterial leaf streak disease of rice.

[0011] As a further preferred embodiment of the present invention, the amount of papain added is 1-2% of the mass of the camphor tree leaves.

[0012] As a further preferred embodiment of the present invention, the enzymatic hydrolysis temperature is 25-27°C; and the enzymatic hydrolysis time is 15-20 min.

[0013] As a further preferred embodiment of the present invention, in the step of applying pressure during the preparation of ramie extract, the pressure application time is 2-5 minutes.

[0014] The present invention also provides the use of the above composition in the prevention and control of bacterial leaf streak in rice.

[0015] Preferably, the above composition is diluted with water 1000-1500 times and sprayed at the late tillering stage and the young panicle differentiation stage of rice. More preferably, the spraying rate is 45-55 kg / mu.

[0016] The present invention discloses the following technical effects: This invention, from the perspective of extracting effective substances from natural plants, provides a natural plant extract composition. This composition is obtained by compounding ramie extract and camphor tree leaf extract obtained by different extraction methods in a certain mass ratio. The composition of this invention effectively improves the unsatisfactory control effect of existing chemical agents on rice bacterial leaf streak, and has significant advantages in terms of economy, environmental friendliness, and excellent control effect. It has important positive significance for promoting the control of rice bacterial leaf streak. Detailed Implementation

[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0018] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0019] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0021] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0022] Example 1 Preparation of the composition (1) Wash and grind the camphor leaves, then add 8 times their weight of deionized water, then add 2% of the weight of the camphor leaves of papain, and enzymatically hydrolyze at 27°C for 20 min. After the enzymatic hydrolysis is completed, raise the temperature to 95°C to inactivate the enzyme, then lower the system to room temperature, filter, and collect the filtrate; then concentrate the obtained filtrate and dry it at 60°C for 20 min to obtain camphor leaf extract.

[0023] (2) After crushing the ramie, mix it with water, then apply a pressure of 155 MPa to the mixture for 5 minutes, remove the pressure, filter, and collect the filtrate; adjust the alcohol content of the filtrate to 35%, let it stand, discard the precipitate, then continue to adjust the alcohol content of the system to 55%, let it stand, filter, collect the precipitate, and dry to obtain the ramie extract.

[0024] (3) Mix ramie extract and camphor leaf extract at a mass ratio of 7:2 to obtain a composition.

[0025] Example 2 Preparation of the composition (1) Wash and grind the camphor leaves, then add 10 times their weight of deionized water, then add 2% of the weight of the camphor leaves of papain, and enzymatically hydrolyze at 25°C for 18 min. After the enzymatic hydrolysis is completed, raise the temperature to 95°C to inactivate the enzyme, then lower the system to room temperature, filter, and collect the filtrate; then concentrate the obtained filtrate and dry it at 60°C for 15 min to obtain camphor leaf extract.

[0026] (2) After crushing the ramie, mix it with water, then apply a pressure of 160 MPa to the mixture for 3 minutes, remove the pressure, filter, and collect the filtrate; adjust the alcohol content of the filtrate to 35%, let it stand, discard the precipitate, then continue to adjust the alcohol content of the system to 50%, let it stand, filter, collect the precipitate, and dry to obtain the ramie extract.

[0027] (3) Mix ramie extract and camphor leaf extract at a mass ratio of 6:1 to obtain a composition.

[0028] Example 3 Preparation of the composition (1) Wash and grind the camphor leaves, then add 8 times their weight of deionized water, and then add 1.5% of the weight of the camphor leaves of papain. Enzymatically hydrolyze at 25°C for 20 min. After the enzymatic hydrolysis is completed, raise the temperature to 95°C to inactivate the enzyme. Then lower the system to room temperature, filter, and collect the filtrate. Then concentrate the obtained filtrate and dry it at 60°C for 25 min to obtain camphor leaf extract.

[0029] (2) After crushing the ramie, mix it with water, then apply a pressure of 165 MPa to the mixture for 5 minutes, remove the pressure, filter, and collect the filtrate; adjust the alcohol content of the filtrate to 25%, let it stand, discard the precipitate, then continue to adjust the alcohol content of the system to 50%, let it stand, filter, collect the precipitate, and dry to obtain the ramie extract.

[0030] (3) Mix ramie extract and camphor leaf extract at a mass ratio of 5:2 to obtain a composition.

[0031] Example 4 Preparation of the composition (1) Wash and grind the camphor leaves, then add 8 times their weight of deionized water, and then add 1.5% of the weight of the camphor leaves of papain. The enzyme is hydrolyzed at 25°C for 15 min. After the enzymatic hydrolysis is completed, the temperature is raised to 95°C to inactivate the enzyme. Then the system is cooled to room temperature, filtered, and the filtrate is collected. The filtrate is then concentrated and dried at 60°C for 20 min to obtain camphor leaf extract.

[0032] (2) After crushing the ramie, mix it with water, then apply a pressure of 160 MPa to the mixture for 5 minutes, remove the pressure, filter, and collect the filtrate; adjust the alcohol content of the filtrate to 30%, let it stand, discard the precipitate, then continue to adjust the alcohol content of the system to 50%, let it stand, filter, collect the precipitate, and dry to obtain the ramie extract.

[0033] (3) Mix ramie extract and camphor leaf extract at a mass ratio of 7:1 to obtain a composition.

[0034] Comparative Example 1 The difference from Example 1 is that the precipitate obtained when the filtrate contains 35% alcohol is collected as ramie extract.

[0035] Comparative Example 2 The difference from Example 1 is that camphor leaves in step (1) are replaced with ramie for effective substance extraction; the total mass of the final composition is the same as that in Example 1.

[0036] Effect Verification Experiment 1 The compositions prepared in Examples 1-4 and Comparative Examples 1-2 of this invention were diluted 1000 times, and 200 rice seeds were soaked in the solution for 24 hours. The seeds were then sown in petri dishes. The seeds were cultured for 7 days at 27°C and 12 hours of light per day. After cultivation, the seed germination rate, average seedling sprout length, and seedling root length were measured. A control group treated with sterile water was used. The results are shown in Table 1.

[0037] Table 1 As can be seen from Table 1, the composition of the present invention has no toxic effect on the growth and development of rice and does not affect the normal growth and development of rice seeds.

[0038] Example 2 of effect verification The compositions prepared in Examples 1-4 and Comparative Examples 1-2 of this invention were diluted 1000 times to prepare suspensions of Xanthomonas oryzae pv. oryzicola, the pathogen of rice bacterial leaf streak, at the same concentration. The suspensions were then centrifuged (3500 r / min) for 20 min. The precipitates were washed with sterile water and then streaked onto a culture medium. The inhibition rate of the compositions against Xanthomonas oryzae pv. oryzicola was determined, with sterile water treatment serving as a control. The results are shown in Table 2.

[0039] Table 2 Inhibition rate % = [(Control inhibition zone diameter - Treatment inhibition zone diameter) / Control inhibition zone diameter] × 100.

[0040] Example 3 of effect verification The experiment was conducted in a field in Jiangxi Province during the early stage of bacterial leaf streak disease in rice. Seven treatments were set up, with three replicates per treatment group, for a total of 21 plots, each plot measuring 60 m². 2 There was no significant difference in the incidence of bacterial leaf streak in rice among different plots.

[0041] Experimental groups 1-4 were sprayed with a 1000-fold dilution of the composition obtained in Examples 1-4; control experimental groups 1-2 were sprayed with a 1000-fold dilution of the composition obtained in Comparative Examples 1-2; and the blank control group was sprayed with water.

[0042] The first spraying was carried out at the early stage of bacterial leaf streak disease in rice (late tillering stage): the experimental group and the control group were sprayed with the corresponding diluted solution at a rate of 45 kg / mu, while the blank control group was sprayed with the same amount of water; on the 7th day after the first spraying (the young panicle differentiation stage of rice), the second spraying was carried out, with the same concentration and amount as the first spraying; on the 14th day after the second spraying, the incidence rate and disease index were counted, and the control effect of each group was calculated. The average values ​​are shown in Table 3.

[0043] During the experiment, all groups adopted the same field management measures.

[0044] Table 3 The disease severity grading standards are as follows: Grade 0: No lesions on leaves; Grade 1: Lesion area ≤ 1% of leaf area; Grade 3: 1% of leaf area < lesion area ≤ 5% of leaf area; Grade 5: 5% of leaf area < lesion area ≤ 25% of leaf area; Grade 7: 25% of leaf area < lesion area ≤ 50% of leaf area; Grade 9: Lesion area > 50% of leaf area.

[0045] Disease index = [Σ(disease grade value × number of diseased leaves corresponding to the disease grade) × 100] / (9 × number of leaves surveyed); Control effect (%) = [(disease index of control rice - disease index of treatment rice) / disease index of control rice] × 100.

[0046] During the experimental period of this invention, no other diseases were observed in any of the rice groups.

[0047] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A composition for controlling bacterial leaf streak in rice, characterized in that, The composition comprises the following components in the following mass ratio: ramie extract: camphor leaf extract = 5-8: 1-2; The preparation method of the composition for controlling bacterial leaf streak of rice includes the following steps: Preparation of ramie extract: Ramie is crushed and mixed with water. The resulting mixture is then subjected to a pressure of 155-165 MPa for 2-5 minutes. The mixture is then filtered and the filtrate is collected. The alcohol content of the filtrate is adjusted to 25-35%, and the precipitate is discarded. The alcohol content is then further adjusted to 50-55%. The mixture is allowed to stand, filtered, and the precipitate is collected and dried to obtain the ramie extract. Preparation of camphor leaf extract: Camphor leaves are ground and crushed and mixed with water. Papain is then added for enzymatic hydrolysis to inactivate the enzyme. The filtrate is collected by filtration, and then the filtrate is concentrated and dried to obtain the camphor leaf extract. The ramie extract and the camphor tree leaf extract are mixed in a certain mass ratio to obtain the composition for controlling bacterial leaf streak of rice. The amount of papain added is 1-2% of the mass of the camphor tree leaves; The enzymatic hydrolysis temperature is 25-27℃; the enzymatic hydrolysis time is 15-20 min.

2. The composition according to claim 1, characterized in that, The composition consists of the following components in the following mass ratio: ramie extract: camphor leaf extract = 7:

2.

3. The use of the composition according to any one of claims 1-2 in the prevention and control of bacterial leaf streak in rice.

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