A biological agent for preventing and treating tomato early blight and a preparation method thereof

Abstract

This invention provides a biological agent for controlling early blight in tomatoes and its preparation method, belonging to the field of plant disease control technology. The biological agent of this invention comprises the following components: 0.1-0.5 parts of *Bacillus belye*; 1-5 parts of a compound plant extract; 0.3-0.6 parts of brassosterol; 1-3 parts of malt alkaloid hydrochloride; 1-3 parts of N-methyl-D-glucosamine; 0.5-1.8 parts of adjuvants; and 80-150 parts of water. The biological agent for controlling early blight in tomatoes provided by this invention can effectively reduce the incidence of early blight in tomatoes. Its components are natural, environmentally friendly, biodegradable, and have no toxic side effects. Only a small amount of the biological agent is needed to achieve excellent control of early blight in tomatoes.

Description

Technical Field

[0001] This invention relates to the field of plant disease control technology, specifically to a biological agent for controlling early blight in tomatoes and its preparation method. Background Technology

[0002] Tomato (Solanum lycopersicum L.) is an annual herbaceous plant belonging to the genus Solanum in the family Solanaceae. Tomato fruits are rich in minerals, organic acids, lycopene, and other components, making them an essential ingredient in many households. In recent years, my country's tomato planting industry has developed rapidly, with the planting area continuously expanding, and tomato diseases have also become increasingly severe. Among them, early blight is a major disease that harms tomato yield and quality, and in severe cases can lead to significant yield reductions, sometimes exceeding 50%, or even complete crop failure, especially in Northwest and North my country. Therefore, with the expansion of tomato cultivation areas, early blight seriously threatens tomato production and the healthy and stable development of the tomato industry.

[0003] Early blight of tomato, also known as ring spot or summer blight, is a fungal disease of tomatoes caused by *Alternaria solanacea*. The most prominent characteristic of early blight is the presence of distinct concentric rings on lesions, whether on the fruit, leaves, or main stem, hence its name. Fruit lesions often appear near the fruit stem, stem lesions at branching points, and leaf lesions on the leaf tissue. The disease can cause leaf and fruit drop, and branch breakage, significantly impacting yield.

[0004] Currently, the main methods for controlling early blight in tomatoes include agricultural control, chemical control, and biological control. Agricultural control refers to techniques such as screening resistant varieties, implementing crop rotation, and arranging reasonable planting densities. While environmentally friendly, agricultural control has drawbacks such as long and difficult breeding cycles for resistant varieties, and limitations imposed by land resources and environmental conditions. Chemical control involves applying chemical fungicides to reduce early blight in tomatoes. Commonly used chemical fungicides include mancozeb, azoxystrobin, difenoconazole, prochloraz, and iprodione. While effective, chemical control suffers from pesticide residues, environmental pollution, and the development of resistance. Biological control refers to the use of microbial biological agents or preparations containing microbial metabolites to control the disease. Biological control is gaining increasing attention due to its low cost and high safety. Summary of the Invention

[0005] In view of this, the present invention provides a biological agent for the prevention and control of early blight in tomatoes, wherein the biological agent comprises the following components in parts by weight:

[0006] Bacillus vesiculus 0.1-0.5 parts; compound plant extract 1-5 parts; brassosterol 0.3-0.6 parts; barley malt alkaloid hydrochloride 1-3 parts; N-methyl-D-glucosamine 1-3 parts; adjuvants 0.5-1.8 parts; water 80-150 parts.

[0007] Furthermore, the preparation method of the compound plant extract includes the following steps:

[0008] ε-polylysine was dissolved in deionized water and diluted with anhydrous ethanol to obtain a diluted solution. Ferulic acid, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added to the diluted solution and ultrasonically dispersed until uniform. The pH of the system was adjusted to 6.5, centrifuged, and the precipitate was collected, washed, and dried to obtain an intermediate product. The intermediate product was dissolved in acetic acid solution at pH=3. After complete dissolution, ginkgo leaf extract solution and senna leaf extract solution were added to obtain a compound plant extract.

[0009] Furthermore, the preparation methods of the ginkgo leaf extract solution and senna leaf extract solution are as follows: they are obtained by reflux extraction using isopropanol as the solvent.

[0010] Furthermore, the ultrasonic dispersion conditions are: 400-500W ultrasonic treatment for 20-40 minutes.

[0011] Furthermore, the centrifugation conditions are: 3000-5000 r / min for 10-20 min.

[0012] Furthermore, the additives include at least one of dispersants and stabilizers.

[0013] Furthermore, the dispersant is selected from at least one of sodium dodecylbenzenesulfonate, polyvinyl alcohol, and sodium lignosulfonate.

[0014] Furthermore, the stabilizer is selected from at least one of butylated hydroxyanisole and dipotassium hydrogen phosphate.

[0015] This invention provides a method for preparing the biological agent for controlling early blight of tomatoes, comprising: mixing Bacillus berreatus, compound plant extract, brassosterol, barley malt alkaloid hydrochloride, N-methyl-D-glucosamine, adjuvants and water in a certain proportion.

[0016] The present invention also provides the application of the biological agent for controlling early blight of tomatoes. One week after tomato transplanting, the biological agent for controlling early blight of tomatoes is sprayed on the surface of tomato leaves at a dosage of 0.2-0.5 mL / plant.

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

[0018] The Bacillus berleis in the biological agent for controlling early blight of tomato provided by this invention inhibits the growth of pathogenic mycelia by secreting antimicrobial peptides and enzymes, and at the same time controls fungal diseases by competing for nutrients, space or inducing plant systemic resistance (ISR).

[0019] This invention uses ε-polylysine and ferulic acid as carriers to load plant active ingredients, which can not only improve the stability and persistence of plant active ingredients, but also enhance the destructive power of plant active ingredients on the cell walls of pathogenic fungi and inhibit mycelial growth. In other words, it can improve the control effect while reducing the dosage and reduce the incidence of early blight in tomatoes.

[0020] The compound plant extracts added in this invention reduce spore attachment and germination by forming a dense physical barrier on the plant surface, thereby improving the control effect of pathogens.

[0021] This invention is the first to propose a biological agent for controlling early blight in tomatoes, combining Bacillus belye, compound plant extracts, brassosterol, malt alkaloid hydrochloride, and N-methyl-D-glucosamine, which can effectively reduce the incidence of early blight in tomatoes. In this invention, malt alkaloid hydrochloride and N-methyl-D-glucosamine are used as synergists to improve the utilization of the active ingredients, enhance the inhibitory effect of the biological agent on the pathogen, and reduce the incidence of early blight in tomatoes.

[0022] The biological agent for controlling early blight of tomatoes provided by this invention has the characteristics of being natural and environmentally friendly, biodegradable, and having no toxic side effects. Detailed Implementation

[0023] This invention provides a biological agent for controlling early blight in tomatoes. The biological agent comprises the following components by weight: 0.1-0.5 parts of Bacillus berberis; 1-5 parts of compound plant extract; 0.3-0.6 parts of brassosterol; 1-3 parts of barley malt alkaloid hydrochloride; 1-3 parts of N-methyl-D-glucosamine; 0.5-1.8 parts of adjuvant; and 80-150 parts of water.

[0024] Preferably, the biological agent for controlling early blight of tomatoes comprises, by weight, the following components: 0.1-0.3 parts of Bacillus berberis; 2-4 parts of compound plant extract; 0.5-0.6 parts of brassosterol; 2-3 parts of barley malt alkaloid hydrochloride; 1-2 parts of N-methyl-D-glucosamine; 0.7-1.5 parts of adjuvant; and 90-130 parts of water.

[0025] More preferably, the biological agent for controlling early blight of tomato comprises, by weight, the following components: 0.2 parts of Bacillus berberis; 4 parts of compound plant extract; 0.5 parts of brassosterol; 3 parts of barley malt alkaloid hydrochloride; 1 part of N-methyl-D-glucosamine; 1.1 parts of adjuvant; and 100 parts of water.

[0026] In some embodiments of the present invention, the preparation method of the compound plant extract includes the following steps:

[0027] ε-polylysine was dissolved in deionized water and diluted with anhydrous ethanol to obtain a diluted solution. Ferulic acid, N-hydroxysuccinimide, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) were added to the diluted solution and ultrasonically dispersed until uniform. The pH of the system was adjusted to 6.5, centrifuged, and the precipitate was collected, washed, and dried to obtain an intermediate product. The intermediate product was dissolved in an acetic acid solution at pH=3. After complete dissolution, ginkgo leaf extract solution and senna leaf extract solution were added to obtain a compound plant extract.

[0028] In this invention, ε-polylysine, a natural antibacterial polypeptide containing multiple amino groups, is covalently linked with ferulic acid to form a composite carrier. The two work synergistically to enhance the destructive ability against the cell walls of pathogenic fungi. The carrier loads active ingredients from plant extracts; while possessing antibacterial activity itself, it also enhances the adhesion and persistence of plant extracts on leaf surfaces.

[0029] In this invention, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) are used as activators. 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) first activates the carboxyl group in ferulic acid to form an unstable intermediate. N-hydroxysuccinimide reacts with the activated intermediate to generate a more stable intermediate. This intermediate reacts more efficiently with ε-polylysine, while having fewer side reactions.

[0030] In some embodiments of the present invention, the ginkgo leaf extract solution and senna leaf extract solution are prepared by reflux extraction using isopropanol as the solvent.

[0031] In some embodiments of the present invention, the ultrasonic dispersion conditions are: ultrasonic treatment at 400-500W for 20-40 minutes. Preferably, the ultrasonic dispersion conditions are: stirring at 500 r / min for 12 hours.

[0032] In some embodiments of the present invention, the centrifugation conditions are: centrifugation at 3000-5000 r / min for 10-20 min. Preferably, the centrifugation conditions are: centrifugation at 3000 r / min for 20 min.

[0033] In some embodiments of the present invention, the adjuvant includes at least one of a dispersant and a stabilizer.

[0034] In some embodiments of the present invention, the dispersant is selected from at least one of sodium dodecylbenzenesulfonate, polyvinyl alcohol, and sodium lignosulfonate.

[0035] In some embodiments of the present invention, the stabilizer is selected from at least one of butylated hydroxyanisole and dipotassium hydrogen phosphate.

[0036] This invention provides a method for preparing the biological agent for controlling early blight of tomatoes, comprising: mixing Bacillus berreatus, compound plant extract, brassosterol, barley malt alkaloid hydrochloride, N-methyl-D-glucosamine, adjuvants and water in a certain proportion.

[0037] The present invention also provides the application of the biological agent for controlling early blight of tomatoes. One week after tomato transplanting, the biological agent for controlling early blight of tomatoes is sprayed on the surface of tomato leaves at a dosage of 0.2-0.5 mL / plant.

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0040] Unless otherwise specified, all experiments were repeated 3 times.

[0041] Analysis of variance (ANOVA) and Duncan's multiple comparison analysis were performed using SPSS 21.0. Results are expressed as mean ± standard deviation, and P < 0.05 indicates a significant difference.

[0042] Bacillus belye; deposited at the China General Microbiological Culture Collection Center, address: No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing; deposit date: November 16, 2020; accession number: CGMCC NO. 21190. The Bacillus belye described in this invention was commercially purchased. This invention does not claim protection for Bacillus belye.

[0043] The Bacillus berberis is added in the form of a bacterial powder, wherein the effective viable bacteria count in the bacterial powder is 20 billion / g.

[0044] Malt alkaloid hydrochloride, CAS No.: 6027-23-2, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0045] N-methyl-D-glucosamine, CAS No.: 6284-40-8, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0046] Brassosterol, also known as brassosterol, CAS No.: 474-67-9, was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0047] ε-Polylysine, CAS No.: 28211-04-3.

[0048] Ferulic acid, CAS No.: 1135-24-6.

[0049] N-hydroxysuccinimide, CAS No.: 6066-82-6.

[0050] 1-Ethyl-(3-dimethylaminopropyl)carbodiimide, CAS: 1892-57-5.

[0051] The preparation method of the compound plant extract is as follows:

[0052] (1) Dry the ginkgo leaves to constant weight, pulverize them and pass them through a 20-mesh sieve to obtain ginkgo leaf powder; then mix the ginkgo leaf powder with isopropanol at a material-liquid ratio of 1:22, reflux at 80°C for 2 hours, and extract once. After extraction, centrifuge (3000 r / min, centrifuge for 10 min), concentrate under reduced pressure to remove residual isopropanol, then add 2 times the amount of distilled water to the obtained extract, and sonicate for 5 min to obtain ginkgo leaf extract solution;

[0053] (2) After drying and pulverizing the senna leaves, pass them through a 20-mesh sieve to obtain senna leaf powder; then mix the senna leaf powder with isopropanol at a material-to-liquid ratio of 1:20, reflux at 80°C for 2.5 hours, and extract once. After extraction, centrifuge (3000 r / min, centrifuge for 10 min), concentrate under reduced pressure to remove residual isopropanol, then add 2 times the amount of distilled water to the obtained extract, and sonicate for 5 min to obtain senna leaf extract solution;

[0054] (3) Dissolve 5g of ε-polylysine in 60mL of deionized water. After dissolution, dilute with 45mL of anhydrous ethanol to obtain a diluted solution. Add 132.6mg of ferulic acid, 202µL of N-hydroxysuccinimide and 281µL of 1-ethyl-(3-dimethylaminopropyl)carbodiimide to the diluted solution. Sonicate at 500W for 30min. Then adjust the pH of the system to 6.5 with hydrochloric acid. Centrifuge at 3000 r / min for 20min. Wash three times with deionized water and vacuum dry at 80℃ to obtain the intermediate product.

[0055] (4) Weigh 1g of intermediate product and dissolve it in 10 mL of acetic acid solution with pH 3. After complete dissolution, add 25 mL of ginkgo leaf extract solution and 25 mL of senna leaf extract solution and disperse evenly to obtain a compound plant extract.

[0056] Example 1

[0057] A method for preparing a biological agent for controlling early blight of tomatoes includes the following steps: 0.2 parts of Bacillus bellis; 4 parts of compound plant extract; 0.5 parts of brassosterol; 3 parts of barley malt alkaloid hydrochloride; 1 part of N-methyl-D-glucosamine; 0.5 parts of sodium dodecylbenzenesulfonate; 0.5 parts of butylated hydroxyanisole; and 100 parts of water are mixed in a certain proportion to obtain the biological agent for controlling early blight of tomatoes.

[0058] Example 2

[0059] A method for preparing a biological agent for controlling early blight of tomatoes includes the following steps: 0.1 parts of Bacillus berberis; 1 part of compound plant extract; 0.3 parts of brassosterol; 1 part of barley malt alkaloid hydrochloride; 2 parts of N-methyl-D-glucosamine; 0.5 parts of sodium dodecylbenzenesulfonate; 0.5 parts of butylated hydroxyanisole; and 80 parts of water are mixed in a certain proportion to obtain the biological agent for controlling early blight of tomatoes.

[0060] Example 3

[0061] A method for preparing a biological agent for controlling early blight of tomatoes includes the following steps: 0.3 parts of Bacillus bellis; 4 parts of compound plant extract; 0.6 parts of brassosterol; 3 parts of barley malt alkaloid hydrochloride; 2 parts of N-methyl-D-glucosamine; 0.5 parts of sodium dodecylbenzenesulfonate; 0.5 parts of butylated hydroxyanisole; and 130 parts of water are mixed in a certain proportion to obtain the biological agent for controlling early blight of tomatoes.

[0062] Example 4

[0063] A method for preparing a biological agent for controlling early blight of tomatoes includes the following steps: 0.1 parts of Bacillus bellis; 2 parts of compound plant extract; 0.5 parts of brassosterol; 2 parts of barley malt alkaloid hydrochloride; 1 part of N-methyl-D-glucosamine; 0.5 parts of sodium dodecylbenzenesulfonate; 0.5 parts of butylated hydroxyanisole; and 90 parts of water are mixed in a certain proportion to obtain the biological agent for controlling early blight of tomatoes.

[0064] Example 5

[0065] A method for preparing a biological agent for controlling early blight of tomatoes includes the following steps: 0.5 parts of Bacillus bellis; 5 parts of compound plant extract; 0.6 parts of brassosterol; 3 parts of barley malt alkaloid hydrochloride; 1 part of N-methyl-D-glucosamine; 0.5 parts of sodium dodecylbenzenesulfonate; 0.5 parts of butylated hydroxyanisole; and 150 parts of water are mixed in a certain proportion to obtain the biological agent for controlling early blight of tomatoes.

[0066] Comparative Example 1

[0067] Same as Example 1, except that it does not contain Bacillus belye.

[0068] Comparative Example 2

[0069] Same as Example 1, except that it does not contain compound plant extracts.

[0070] Comparative Example 3

[0071] Same as Example 1, except that it does not contain brassosterol.

[0072] Comparative Example 4

[0073] Same as Example 1, except that it does not contain barley malt alkaloid hydrochloride.

[0074] Comparative Example 5

[0075] Same as Example 1, except that it does not contain N-methyl-D-glucosamine.

[0076] Comparative Example 6

[0077] Same as Example 1, except that the preparation method of the compound plant extract is as follows:

[0078] (1) Dry the ginkgo leaves to constant weight, pulverize them and pass them through a 20-mesh sieve to obtain ginkgo leaf powder; then mix the ginkgo leaf powder with isopropanol at a material-to-liquid ratio of 1:22, reflux at 80°C for 2 hours, and extract once. After extraction, centrifuge (3000 r / min, centrifuge for 10 min), concentrate under reduced pressure to remove residual isopropanol, then add 2 times the amount of distilled water to the obtained extract, and sonicate for 5 min to obtain ginkgo leaf extract solution;

[0079] (2) After drying and pulverizing the senna leaves, pass them through a 20-mesh sieve to obtain senna leaf powder. Then, mix the senna leaf powder with isopropanol at a material-to-liquid ratio of 1:20, reflux at 80°C for 2.5 hours, and extract once. After extraction, centrifuge (3000 r / min, centrifuge for 10 min), concentrate under reduced pressure to remove residual isopropanol, and then add 2 times the amount of distilled water to the obtained extract and sonicate for 5 min to obtain senna leaf extract solution.

[0080] (3) Mix 25 mL of Ginkgo biloba extract solution and 25 mL of Senna extract solution and stir well to obtain a compound plant extract.

[0081] Performance testing

[0082] (a) The effect of the prepared biological agent on mycelial growth.

[0083] Test method: Under aseptic conditions, add 2 mL of the biological agent prepared in the examples or comparative examples to 28 mL of liquid PDA medium, shake well, and pour into plates, 10 mL per plate. A blank control group is prepared by replacing the biological agent medium with an equal volume of distilled water. Select uniformly growing Alternaria alternata plates, and use a sterilized punch (6 mm diameter) to evenly punch out mycelial cakes (6 mm in diameter) with the same growth rate and area.

[0084] The mycelial cakes were inoculated onto each PDA medium plate, and the plates were inverted in the center of each plate. The plates were incubated at 27°C under constant temperature and light for 20 days. The growth of the colonies was observed every 5 days. The diameter of the colonies was measured using the cross-cross method. The average value was used as the result, and the mycelial growth inhibition rate was calculated. The results are shown in Table 1.

[0085] Mycelial growth inhibition rate (%) = (colony diameter of blank control group plate - colony diameter of treatment group plate) / (colony diameter of blank control group plate - diameter of mycelial cake) × 100.

[0086] Table 1

[0087] Group Mycelial growth inhibition rate (%) Example 1 <![CDATA[88.72±3.72 a ]]> Example 2 <![CDATA[85.42±3.25 c ]]> Example 3 <![CDATA[85.58±3.73 c ]]> Example 4 <![CDATA[86.21±3.47 b ]]> Example 5 <![CDATA[85.84±2.68 bc ]]> Comparative Example 1 <![CDATA[55.36±1.13 f ]]> Comparative Example 2 <![CDATA[53.64±1.07 g ]]> Comparative Example 3 <![CDATA[65.13±1.38 e ]]> Comparative Example 4 <![CDATA[55.27±1.84 f ]]> Comparative Example 5 <![CDATA[50.52±3.19 h ]]> Comparative Example 6 <![CDATA[75.17±3.06 d ]]>

[0088] Note: Different lowercase letters in the same column in Table 1 indicate a significant difference between the two (P < 0.05).

[0089] (ii) Field trials

[0090] Experimental area: Wuqing Experimental Site, Modern Agricultural Innovation Base, Tianjin Academy of Agricultural Sciences. Tomatoes were managed according to conventional planting methods. The selected experimental area was randomly divided into several experimental treatment groups and one blank control group. The experimental areas were sprayed with the biological agent provided in the examples or comparative examples, while the blank control group was sprayed with an equal volume of water.

[0091] Experimental varieties: Tomato seeds: Provence, Zhongshu No. 4.

[0092] Test method:

[0093] 1) When the tomato seedlings have grown to 6-8 leaves, the biological agent prepared in the examples, comparative examples, and blank control groups is sprayed onto the leaf surface at a dosage of 0.5 mL / plant, once every 7 days, for a total of 5 sprays. Forty days after spraying, samples are taken at 5 points in a "Z" pattern, with 100 plants in each group. The number of diseased leaves, the number of diseased plants, and the grade of diseased leaves are counted and recorded.

[0094] The disease grading criteria are as follows:

[0095] Grade 0: The entire plant is healthy and no lesions are visible;

[0096] Grade 1: The disease is relatively mild, with diseased leaves accounting for less than 1 / 4 of the total number of leaves on the plant;

[0097] Grade 2: Moderate disease incidence, with diseased leaves accounting for 1 / 4 to 1 / 2 of the total number of leaves on the plant, and a small number of lesions appearing on the stems;

[0098] Grade 3: The disease is more severe, with diseased leaves accounting for 1 / 2 to 3 / 4 of the total leaves of the plant, and lesions appearing on more than one-fifth of the stem. A small number of lesions also appear on the fruit.

[0099] Level 4: The disease is severe, with more than 3 / 4 of the total leaves on the plant affected, and most of the leaves have withered and died.

[0100] The incidence rate, disease index, and prevention and control effectiveness are calculated using the following formulas.

[0101] ;

[0102] ;

[0103] .

[0104] Table 2

[0105] Group Incidence rate (%) Disease severity index (%) Prevention and control efficacy (%) Blank control group <![CDATA[78.30±4.52 a ]]> <![CDATA[73.85±10.43 a ]]> / Example 1 <![CDATA[10.96±3.64 h ]]> <![CDATA[22.52±13.59 g ]]> <![CDATA[88.76±12.35 a ]]> Example 2 <![CDATA[10.82±2.35 h ]]> <![CDATA[21.63±11.64 h ]]> <![CDATA[88.59±10.46 a ]]> Example 3 <![CDATA[11.57±1.84 g ]]> <![CDATA[22.37±10.53 g ]]> <![CDATA[88.26±11.37 a ]]> Example 4 <![CDATA[10.68±3.51 h ]]> <![CDATA[21.23±9.64 h ]]> <![CDATA[87.61±9.38 ab ]]> Example 5 <![CDATA[11.36±1.36 g ]]> <![CDATA[21.26±8.36 h ]]> <![CDATA[88.06±9.49 a ]]> Comparative Example 1 <![CDATA[54.75±4.64 b ]]> <![CDATA[46.46±5.74 b ]]> <![CDATA[70.47±8.36 e ]]> Comparative Example 2 <![CDATA[50.36±3.67 c ]]> <![CDATA[39.44±3.65 c ]]> <![CDATA[55.85±7.83 f ]]> Comparative Example 3 <![CDATA[33.58±1.34 d ]]> <![CDATA[37.83±6.73 d ]]> <![CDATA[71.58±8.37 d ]]> Comparative Example 4 <![CDATA[20.60±4.53 e ]]> <![CDATA[28.84±.5.56 e ]]> <![CDATA[70.53±4.17 e ]]> Comparative Example 5 <![CDATA[15.53±1.75 f ]]> <![CDATA[27.53±14.62 f ]]> <![CDATA[72.24±8.96 c ]]> Comparative Example 6 <![CDATA[20.64±2.98 e ]]> <![CDATA[27.64±10.71 f ]]> <![CDATA[75.86±7.85 b ]]>

[0106] Note: Different lowercase letters in the same column in Table 2 indicate a significant difference between the two (P < 0.05).

[0107] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A biological agent for controlling early blight in tomatoes, characterized in that, The biological agent, by weight, comprises the following components: Bacillus vesiculus 0.1-0.5 parts; compound plant extract 1-5 parts; brassosterol 0.3-0.6 parts; barley malt alkaloid hydrochloride 1-3 parts; 1-3 parts N-methyl-D-glucosamine, 0.5-1.8 parts auxiliaries, and 80-150 parts water.

2. The biological agent for controlling early blight of tomato according to claim 1, characterized in that, The preparation method of the compound plant extract includes the following steps: ε-polylysine was dissolved in deionized water and diluted with anhydrous ethanol to obtain a diluted solution. Ferulic acid, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added to the diluted solution and ultrasonically dispersed until uniform. The pH of the system was adjusted to 6.5, centrifuged, and the precipitate was collected, washed, and dried to obtain an intermediate product. The intermediate product was dissolved in acetic acid solution at pH=3. After complete dissolution, ginkgo leaf extract solution and senna leaf extract solution were added to obtain a compound plant extract.

3. The biological agent for controlling early blight of tomato according to claim 2, characterized in that, The ginkgo leaf extract solution and senna leaf extract solution were prepared by reflux extraction using isopropanol as the solvent.

4. The biological agent for controlling early blight of tomato according to claim 2, characterized in that, The ultrasonic dispersion conditions are as follows: ultrasonic treatment at 400-500W for 20-40 minutes.

5. The biological agent for controlling early blight of tomato according to claim 2, characterized in that, Centrifuge at 3000-5000 r / min for 10-20 min.

6. The biological agent for controlling early blight of tomato according to claim 1, characterized in that, The additives include at least one of dispersants and stabilizers.

7. The biological agent for controlling early blight of tomato according to claim 1, characterized in that, The dispersant is selected from at least one of sodium dodecylbenzenesulfonate, polyvinyl alcohol, and sodium lignosulfonate.

8. The biological agent for controlling early blight of tomato according to claim 1, characterized in that, The stabilizer is selected from at least one of butylated hydroxyanisole and dipotassium hydrogen phosphate.

9. A method for preparing the biological agent for controlling early blight of tomato according to any one of claims 1-8, comprising the following steps: (1) Mix Bacillus vesiculosus, compound plant extract, brassosterol, barley malt alkaloid hydrochloride, N-methyl-D-glucosamine, adjuvants and water in proportion.

10. The application of the biological agent for controlling early blight of tomato according to any one of claims 1-8, or the biological agent for controlling early blight of tomato prepared according to the method of claim 9, characterized in that, One week after tomato transplanting, the biological agent for controlling early blight of tomatoes is sprayed onto the surface of the tomato leaves at a dosage of 0.2-0.5 mL per plant.