Compound medicament and comprehensive prevention and treatment method for wheat stem base rot

Abstract

The application discloses a kind of compound medicament and wheat stem base rot comprehensive prevention method, belong to plant disease control technical field.The application is prepared by using compound medicament and seed coating agent by combining streptomyces albus S86 fermentation liquor with kiralate medicament, it is found that the combination has obvious synergistic effect, the inhibition rate of false smut fungus spore germination is higher than single-agent medicament, it is 72.65%;Wheat stem base rot has better field control effect, disease index is 0.02, and the control effect is 73.85%.Field intuition shows that the disease degree of streptomyces albus S86 fermentation liquor and kiralate medicament combination treatment group is lighter than other treatment groups as a whole.This provides a basis for the biological control of wheat stem base rot in the future, and has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of plant disease control technology, and in particular to a compound agent and a comprehensive control method for wheat stem base rot. Background Technology

[0002] Wheat stem rot is a soil-borne fungal disease caused by various Fusarium fungi, including *Fusarium graminearum*. The affected area exceeds 2.6667 million hectares. 2 Wheat stem rot can occur throughout the entire wheat growth cycle, generally causing a 3-5% yield reduction in ordinary fields, a 10-20% reduction in severely affected fields, and in a few cases, a reduction of over 50% or even total crop failure, becoming a major obstacle to increasing wheat yield. An effective control method is urgently needed in agricultural production to prevent wheat stem rot. In recent years, wheat stem rot has spread widely throughout the world, attracting widespread international attention.

[0003] Currently, the control of wheat stem rot mainly relies on chemical pesticides and the breeding of disease-resistant varieties. However, long-term use of chemical agents alone can easily lead to increased resistance in pathogens and poses risks of environmental pollution and pesticide residues. Biopesticides, as an important component of green agricultural pest control, have greatly reduced the use of chemical pesticides and offer advantages such as safety, greenness, high efficiency, and sustainability. Biopesticides have also achieved certain results in controlling wheat stem rot. *Pseudomonas cepacia* can significantly reduce the damage of *Fusarium graminearum* to wheat and has a significant yield-increasing effect; *Trichoderma harzianum* has a certain inhibitory effect on *Fusarium graminearum*. Compared with single fungicides, compound combinations are more effective in controlling pathogens. *Bacillus subtilis* YB-15 can significantly reduce the incidence of wheat stem rot and promote wheat seedling growth; the combined use of *Bacillus subtilis* YB-05 bacterial suspension and 1% shenqinmycin suspension has an even more significant effect.

[0004] Streptomyces simonii S86 is a biocontrol fungus isolated from the Agricultural Antibiotics Group of the National Key Laboratory of Integrated Pest Management, Institute of Plant Protection, Chinese Academy of Agricultural Sciences. It was deposited at the China General Microbiological Culture Collection Center (CGMCC No. 29077) on November 21, 2023. Streptomyces simonii S86 produces gray spores, and the colonies are gray. The hyphae are highly branched and unbroken, producing tightly spirally arranged spore filaments. Studies have found that this strain significantly promotes plant growth. During fermentation, it produces various secondary metabolites such as anethole, nystatin, natamycin, and fungicide, which have significant antagonistic effects on various wheat diseases (such as Fusarium and Botrytis cinerea). However, its single-agent effect on wheat stem rot is not significant. Therefore, the combined use of multiple fungicides is of great significance for the control of plant diseases. Summary of the Invention

[0005] The purpose of this invention is to provide a compound agent and a comprehensive control method for wheat stem base rot, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] In a first aspect, the present invention provides a compound agent, which is composed of Streptomyces cephalosporin S86 fermentation broth and cyazofamid agent.

[0008] Preferably, the concentration of Streptomyces cymosus S86 fermentation broth in the compound agent is 8.43 mL / L, and the concentration of cyazofamid agent is 0.359 mg / L.

[0009] Preferably, the volume ratio of Streptomyces cymoxanil S86 fermentation broth to cyazofamid in the compound agent is 1:9.

[0010] Secondly, the present invention also provides a novel seed coating agent, wherein the seed coating agent contains the aforementioned compound agent.

[0011] Preferably, the seed coating agent further comprises seed coating-acceptable micronutrients, plant growth regulators, film-forming agents, antifreeze agents, substrate wetting agents, or other adjuvants.

[0012] Preferably, the dosage of the seed coating agent is: 1 mL of seed coating agent for every 50 g of wheat seeds.

[0013] Thirdly, the present invention also provides the application of the compound agent or the seed dressing agent in the prevention and control of wheat stem rot.

[0014] Fourthly, the present invention also provides a comprehensive control method for wheat stem base rot, the specific method being: coating wheat with a seed dressing agent before sowing, and applying a compound agent during the flowering period, thereby achieving comprehensive control of wheat stem base rot;

[0015] The seed coating agent used for the coating is the aforementioned seed coating agent;

[0016] The compound agent used during the flowering period is the compound agent described above.

[0017] The present invention discloses the following technical effects:

[0018] This invention utilizes a combination of *Streptomyces simonii* S86 fermentation broth and cyazofamid to prepare compound pesticides and seed dressings. The results showed a significant synergistic effect, with a 72.65% inhibition rate against *Fusarium graminearum* spore germination compared to single-agent formulations. It also demonstrated good field control efficacy against wheat stem rot, with a disease index of 0.02 and a control efficacy of 73.85%. Field observations showed that the treatment group using the *Streptomyces simonii* S86 fermentation broth combined with cyazofamid exhibited a generally milder disease severity compared to other treatment groups. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The antibacterial effect of S86 fermentation broth on Fusarium oxysporum;

[0021] Figure 2 The effect of S86 fermentation broth + cyazofamid compound agent on the mycelial morphology of Fusarium graminearum. Detailed Implementation

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Example 1

[0028] 1. Test materials

[0029] The tested strains were Streptomyces simonii S86 and Fusariumpseudograminearum, both provided by the Agricultural Antibiotics Group of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences.

[0030] The tested fungicides, namely cyazofamid, tebuconazole, shenqinmycin, prochloraz, and prothioconazole, were all provided by the Agricultural Antibiotics Group of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences.

[0031] Culture medium formulation

[0032] PDA medium: 200 g / L potato, 15 g / L agar powder, 20 g / L glucose, 1 L water.

[0033] Fermentation medium: 20g glucose, 30g cornmeal, 20g soybean flour, 4g ammonium chloride, 3g calcium carbonate, plus 1L deionized water.

[0034] Preparation of S86 fermentation broth: Using a sterile scalpel, S86 strain was cut into 1cm pieces. 2 Small pieces were inoculated into the fermentation medium and cultured at 28℃ and 220r / min for 72h before being filtered to obtain the fermentation broth.

[0035] 2. Experimental Methods

[0036] 2.1 Determination of the toxicity of Streptomyces simonii S86 fermentation broth to Fusarium oxysporum.

[0037] The antibacterial activity of different agents against *Fusarium graminearum* was determined using the mycelial growth rate method. S86 fermentation broth was filtered through a 0.22 μm bacterial filter. The sterile fermentation broth was added to PDA medium to achieve final concentrations of 3.87, 5.62, 7.03, 9.84, 12.8, and 16.64 mL / L. After mixing, the medium was poured onto a plate and allowed to solidify. Using a sterile punch, 5 mm *Fusarium graminearum* mycelial discs were inoculated into the center of the drug-containing PDA plates. Medium without fermentation broth served as a control. Each treatment was replicated five times. The plates were incubated at 25°C inverted for 5 days.

[0038] 2.2 Virulence determination of five chemical agents against Fusarium graminearum

[0039] Five chemical agents—cypermethrin, tebuconazole, shenqinmycin, prothioconazole, and imazalil—were added to PDAs to create five concentration treatments (Table 1). *Fusarium graminearum* mycelial cakes of the same size were placed in the center of the drug-containing PDA plates, and the colony diameter was measured. Each treatment was repeated three times, with PDA plates without any agents serving as a control. After 5 days of mycelial growth, the colony diameter was measured using the cross-multiplication method, and the inhibition rate was calculated. The logarithm of the agent concentration was used as the independent variable (X), and the mycelial growth inhibition rate as the dependent variable (Y). toxicity regression curve analysis was performed using SPSS software to determine the effective inhibitory concentration (EC50) of each agent against *Fusarium graminearum*. 50 Inhibition rate (%) = [(control colony diameter - treated colony diameter) / control colony diameter] × 100.

[0040] Table 1 Design of Concentration Gradients for Each Drug

[0041]

[0042] 2.3 Screening of Synergistic Effect Ratio of Mixed Agents

[0043] The compounding ratio was screened according to the Horsfall method, and the EC values ​​of each single dose were... 50 Based on the above, compound pesticides were prepared by mixing S86 fermentation broth with five different chemical pesticides at volume ratios of 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, and 10:0, and then used to treat *Fusarium graminearum*. Using the mycelial growth rate method, the compound pesticides prepared at different volume ratios were added to PDA medium to obtain drug-containing mixed mediums for different treatment groups. *Fusarium graminearum* mycelial cakes of the same size were inoculated into the center of the medium, with plates without pesticides serving as controls. Each treatment was repeated three times. The colony diameter was measured using the cross-cross method, and the average inhibition rate and theoretical inhibition rate of the compound pesticides at different volume ratios were calculated.

[0044] Expected control efficacy (%) = (EC of single agent A) 50 (actual inhibition rate of dose × percentage of formulation) + (EC of single dose B) 50 (Actual inhibition rate of dose × percentage of formulation);

[0045] Toxicity ratio = Actual inhibition rate / Expected inhibition rate;

[0046] If the toxicity ratio is significantly >1.080, it is a synergistic effect; if the toxicity ratio is 0.9-1.080, it is an additive effect; if the toxicity ratio is significantly <0.9, it is an antagonistic effect.

[0047] 2.4 Effects of compound agents on the mycelial growth morphology of Fusarium graminearum

[0048] The reagent was diluted with PDA medium to obtain a concentration of EC. 50 S86 fermentation broth with a concentration of EC 50 Cyazofamids, S86 fermentation broth EC 50 +Cyperazin EC 50 PDA agar plates containing the drug (volume ratio 1:9) were prepared. Sterilized cellophane was placed on the surface of the culture medium and air-dried. Fusarium graminearum mycelial cakes were then placed in the center of the cellophane. The control group (without the drug) was used. Each treatment was repeated three times. The plates were incubated at 25°C for 48 hours. The differences in mycelial morphology between the control and treatment groups were observed using a biological microscope.

[0049] 2.5 Effects of synergistic combinations on spore germination of Fusarium pseudograss

[0050] Preparation of drug-containing culture media: Three groups of agents were selected: single S86 fermentation broth, single cyazofamid, and a combination of S86 fermentation broth and cyazofamid. These were added to 100 mL of CMC sporulation medium and mixed thoroughly. The concentrations of S86 fermentation broth in the single S86 fermentation broth group were 8.43 mL / L, the concentration of cyazofamid in the single cyazofamid group was 0.359 mg / L, and the concentrations of S86 fermentation broth and cyazofamid in the combined group were 8.43 mL / L and 0.359 mg / L respectively (mixed at a volume ratio of 1:9). Then, using a sterile punch, 6 *Fusarium graminearum* mycelial cakes of similar growth conditions were inoculated into each bottle of medium. CMC medium without the agents was used as a control. Each group was repeated three times. After culturing at 25℃ and 180 rpm for 3 days, the spore count was determined using a hemocytometer, and the inhibition rate of spore count for each treatment was calculated using the following formula.

[0051] Inhibition rate (%) = (spore production in control group - spore production in treatment group) / spore production in control group × 100.

[0052] Preparation of a novel seed coating agent based on the synergistic combination of 2.6S86 fermentation broth and cyazofamid.

[0053] Preparation of seed coating agent from fermentation broth: 2% Morwet D-425 (wetting and dispersing agent), 2% Atlox Semsera (purchased from Heda Agriculture), 1% carboxymethyl chitosan, 0.2% xanthan gum, 1% Allura Red, 0.5% Kathon, 2% 1,2-propanediol, 0.5% magnesium aluminum silicate, 1% nano zinc oxide, 0.5% talc, and S86 fermentation broth were added to make up to 100%. The mixture was homogenized using a high-speed homogenizer to obtain the S86 fermentation broth seed coating agent.

[0054] Preparation of the compound seed coating agent: Following the same method, the fungicide cyazofamid was prepared into a suspension: 100 mL of deionized water, 0.383 g of cyazofamid, 2% dispersant, 0.5% talc, and 1% nano zinc oxide were added sequentially to a nano-sand mill. An antifoaming agent was added during grinding to eliminate foam generated during grinding. The mill was set to 2000 rpm and ground for 1 hour to obtain the suspension. 2% film-forming agent, 0.2% xanthan gum, 1% Allura Red, 0.5% Kathon, 2% 1,2-propanediol, and 0.5% magnesium aluminum silicate were added to the suspension and homogenized using a high-speed homogenizer to obtain a cyazofamid seed coating agent with a concentration of 383 mg / L. 50 mL of the cyazofamid suspension and 50 mL of S86 fermentation broth seed coating agent were mixed and homogenized using a high-speed homogenizer to obtain the compound seed coating agent.

[0055] Preparation of coated seeds: Weigh 50g of wheat seeds and place them in a glass petri dish with a diameter of 15cm. Use a pipette to draw 1mL of seed coating agent into the petri dish, cover and shake for 5min. Open the lid, spread the coated seeds evenly, and let them form a film naturally to obtain coated seeds.

[0056] 2.7 The field control effect of S86 combined with different agents on wheat stem rot.

[0057] The experiment was conducted at the Xinxiang Qiliying Experimental Base of the Chinese Academy of Agricultural Sciences. Coated seeds were sown on October 6, 2024, and a second application of the compound pesticide was made on March 28, 2025, at the early flowering stage. The application rate was 100 mL / mu (approximately 667 m²), diluted with 20 liters of water per mu. The experiment included three treatments (S86 + cyazofamid group, Streptomyces S86 fermentation broth group, and cyazofamid·fludioxonil group), with a water treatment as a blank control. Each treatment was replicated three times. The plot area was 20 m². 2 The random block permutation method is used.

[0058] The efficacy observation was conducted on April 30, 2025. The field survey method for wheat stem base rot involved randomly selecting 50 plants from each plot for investigation, recording the total number of plants and the number of diseased plants at each level. Diseased plants were recorded according to the following 5-level grading method. Grading method for wheat stem base rot (by plant):

[0059] Level 0: Asymptomatic;

[0060] Grade 1: The first leaf sheath is slightly yellow;

[0061] Grade 2: The first leaf sheath is completely infected;

[0062] Grade 3: The second leaf sheath is slightly yellow;

[0063] Grade 4: The second leaf sheath is completely infected;

[0064] Level 5: The third leaf sheath is affected;

[0065] The formula for calculating the disease index and plant control efficacy is as follows:

[0066]

[0067] 2.8 Data Processing and Statistical Analysis

[0068] After all data were processed in Excel, descriptive statistics and homogeneity of variance tests were performed on the experimental data using Origin software. Duncan's method was used to analyze the significance of the data. Different lowercase letters represent significant differences between different treatments (P<0.05).

[0069] 3. Experimental Results

[0070] 3.1 Determination of the toxicity of Streptomyces simonii S86 fermentation broth to Fusarium oxysporum

[0071] The toxicity test results of Streptomyces simonii S86 fermentation broth against Fusarium graminearum are as follows: Figure 1 As shown, the growth activity of *Fusarium graminearum* was significantly inhibited after treatment with S86 fermentation broth (p < 0.05), and the inhibitory effect on *Fusarium graminearum* was further enhanced with increasing concentration of S86 fermentation broth. When the concentration of fermentation broth in PDA medium reached 16.64 mL / L, the growth of *Fusarium graminearum* was completely inhibited. SPSS software analysis showed that the EC50 of S86 fermentation broth on *Fusarium graminearum* was significantly reduced. 50 The concentration was 8.43 mL / L, and the toxicity regression equation was y = 5.23 + 5.83x, R0. 2 It is 0.83.

[0072] 3.2 Virulence determination of five agents against Fusarium graminearum

[0073] Linear regression analysis was performed between the mycelial inhibition rate and the logarithmic value of the agent concentration of different fungicides to obtain the toxicity regression equations of each agent against *Fusarium graminearum*. The results are shown in Table 2. 50The values, from largest to smallest, are: shenqinmycin > prothioconazole > cyazofamid > tebuconazole > imazalil, which are 17.314 mg / L, 5.328 mg / L, 0.359 mg / L, 0.355 mg / L, and 0.032 mg / L, respectively.

[0074] Table 2 Different bactericides EC 50 Value determination

[0075]

[0076] 3.3 Combined Effect of Compound Agents on Fusarium oxysporum

[0077] In each single-dose EC 50 Based on the values, S86 fermentation broth was compounded with five different chemical pesticides. Table 3 shows the screening results. In the initial screening of the toxicity ratios of S86 fermentation broth combined with the five chemical agents against *Fusarium graminearum*, only cyazofamid and tebuconazole showed synergistic effects. Specifically, the volume ratios of S86 fermentation broth to cyazofamid were 1:9 and 3:7, with toxicity ratios of 1.391 and 1.215, respectively. In the combination of S86 fermentation broth and tebuconazole, two synergistic combinations appeared: S86 fermentation broth to tebuconazole = 9:1 and 7:3, with toxicity ratios of 1.187 and 1.207, respectively. The remaining pesticides, when combined with S86 fermentation broth, only showed additive combinations, without any synergistic effects. The compound combinations with higher toxicity were selected for subsequent experimental analysis. The co-toxicity coefficient (CTC) was determined for the combination of S86 fermentation broth and cyazofamid in a 1:9 ratio and the combination of S86 fermentation broth and tebuconazole in a 7:3 ratio.

[0078] Table 3 shows the toxicity of S86 mixed with five fungicides to the pathogen causing wheat stem rot and the interaction types of each fungicide pair.

[0079]

[0080]

[0081] Note: The toxicity ratios in the table are categorized into three types: antagonistic (-), additive (=), and synergistic (+).

[0082] 3.4 Determination of the synergistic effect of mixed agents on Fusarium oxysporum

[0083] The co-toxicity coefficients (CTCs) of S86 fermentation broth with synergistic combinations of cyazofamid and tebuconazole, which have high toxicity ratios, were determined. The results showed that the CTC of S86 fermentation broth with cyazofamid at a 1:9 ratio was 131.90, greater than 120, indicating a synergistic effect. However, the CTC of S86 fermentation broth with tebuconazole at a 7:3 ratio was 34.68, less than 80, indicating no synergistic effect (Table 4). Based on the optimal synergistic results, the experiment further investigated the synergistic combination of S86 fermentation broth: cyazofamid at a 1:9 ratio.

[0084] Table 4. Determination of the antifungal effect and synergistic coefficient of two compound combinations against the pathogen of wheat stem rot.

[0085]

[0086] 3.5 Effects of synergistic combinations on the mycelial morphology of *Wheat stem rot* fungus

[0087] Microscopic observation revealed ( Figure 2 In the control group, the mycelium of wheat stem rot fungus was straight and had normal branching. In the S86 fermentation broth treatment, the mycelium of wheat stem rot fungus was curved and disordered. In the treatment with cyazofamid, the mycelium of wheat stem rot fungus had increased branching. In the combination treatment of S86 fermentation broth and cyazofamid, the mycelium of wheat stem rot fungus was twisted and the branching distance was shortened.

[0088] 3.6 Effects of different single agents and synergistic combinations on spore germination of Fusarium pseudograss

[0089] Statistical analysis using a hemocytometer revealed significant differences in the effects of different agents on the spore germination of *Fusarium graminearum*. S86 inhibited the spore germination rate of *Fusarium graminearum* by 60.68%, while cyazofamid inhibited it by 71.37%. The combined agent showed a higher inhibition rate than the single agent, at 72.63% (Table 5).

[0090] Table 5. Effects of S86 fermentation broth, cyazofamid, and their compound agents on spore germination of *Fusarium graminearum*.

[0091]

[0092] Different letters represent significant differences (P < 0.05).

[0093] 3.7 Field control effect of synergistic combination on wheat stem base rot

[0094] A seed dressing agent was prepared based on the highly effective combination of Streptomyces S86 and cyazofamid, and field trials were conducted. The results are shown in Table 6. The disease index of the blank control group was 0.077. The disease index after treatment was generally lower than that of the blank control group, indicating a milder disease severity. The disease indices for each treatment were 0.02, 0.045, and 0.027, respectively. The whitehead rate in the blank treatment group was 7.68%, while the whitehead rate in the compound agent group (S86 + cyazofamid group) was 2.02%, with a control efficacy of 73.85%. The whitehead rate in the Streptomyces S86 fermentation broth group was 3.31%, with a control efficacy of 41.54%. The whitehead rate in the cyazofamid·fludioxonil group was 2.8%, with a control efficacy of 63.85%. Field observations showed that the Streptomyces S86 and cyazofamid treatments resulted in a milder overall disease severity compared to other treatments.

[0095] Table 6. Disease index, whitehead rate, and control efficacy of different pesticide treatments against wheat stem base rot.

[0096]

[0097] 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. The application of a compound pesticide or a seed dressing agent containing the compound pesticide in the control of wheat stem base rot, characterized in that, The compound agent is composed of fermentation broth of Streptomyces simulans S86 and cyazofamid agent; The concentration of the Streptomyces simonii S86 fermentation broth was 8.43 mL / L, and the concentration of the cyazofamid agent was 0.359 mg / L. The volume ratio of Streptomyces cymoxanil S86 fermentation broth to cyazofamid in the compound preparation is 1:

9.

2. The application according to claim 1, characterized in that, The seed coating agent also includes seed coating-acceptable micronutrients, plant growth regulators, film-forming agents, antifreeze agents, substrate wetting agents, or other adjuvants.

3. The application according to claim 1, characterized in that, The dosage of the seed coating agent is as follows: take 1 mL of seed coating agent for every 50 g of wheat seeds.

4. A compound medicine, characterized in that, The compound agent is composed of fermentation broth of Streptomyces simulans S86 and cyazofamid agent; The concentration of the Streptomyces simonii S86 fermentation broth was 8.43 mL / L, and the concentration of the cyazofamid agent was 0.359 mg / L. The volume ratio of Streptomyces cymoxanil S86 fermentation broth to cyazofamid in the compound preparation is 1:

9.

5. A seed coating agent, characterized in that, The seed coating agent contains a compound agent; The compound agent is composed of fermentation broth of Streptomyces simulans S86 and cyazofamid agent; The concentration of the Streptomyces simonii S86 fermentation broth was 8.43 mL / L, and the concentration of the cyazofamid agent was 0.359 mg / L. The volume ratio of Streptomyces cymoxanil S86 fermentation broth to cyazofamid in the compound preparation is 1:

9.

6. The seed coating agent according to claim 5, characterized in that, The seed coating agent also includes seed coating-acceptable micronutrients, plant growth regulators, film-forming agents, antifreeze agents, substrate wetting agents, or other adjuvants.

7. The seed coating agent according to claim 5, characterized in that, The dosage of the seed coating agent is as follows: take 1 mL of seed coating agent for every 50 g of wheat seeds.

8. A comprehensive control method for wheat stem base rot, characterized in that, The specific method is as follows: before sowing, use seed dressing agent to coat wheat, and apply compound agent during the flowering period to achieve comprehensive prevention and control of wheat stem base rot; The seed coating agent used for the coating is the seed coating agent according to claim 5; The compound agent used during the flowering period is the compound agent described in claim 4.

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