阅读说明：本技术 一种用于防治青枯病的杀菌组合物、杀菌剂及应用 (Bactericidal composition for preventing and treating bacterial wilt, bactericide and application ) 是由 牟文君 戴华鑫 林俭 何伟 卓思楚 范建立 宋纪真 张仕祥 奚家勤 翟振 郭建华 于 2021-10-22 设计创作，主要内容包括：本发明属于杀菌组合物领域,具体涉及一种用于防治青枯病的杀菌组合物、杀菌剂及应用。该杀菌组合物由氟啶胺和增效杀菌剂组成,所述增效杀菌剂为噻霉酮；氟啶胺和噻霉酮的质量比为1：(55-80)或4:1。本发明的用于防治青枯病的杀菌组合物,氟啶胺具有氧化磷酸化解偶联活性,氟啶胺与噻霉酮按一定比例复配时,在青枯病防治方面具有增效作用。(The invention belongs to the field of sterilization compositions, and particularly relates to a sterilization composition for preventing and treating bacterial wilt, a bactericide and application. The bactericidal composition consists of fluazinam and a synergistic bactericide, wherein the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (55-80) or 4: 1. The fluazinam has oxidative phosphorylation uncoupling activity, and has synergistic effect in the aspect of bacterial wilt prevention and control when being compounded with the benziothiazolinone according to a certain proportion.)

1. The bactericidal composition for preventing and treating bacterial wilt is characterized by comprising fluazinam and a synergistic bactericide, wherein the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (55-80) or 4: 1.

2. The bactericidal composition for controlling bacterial wilt according to claim 1, wherein the mass ratio of fluazinam to benziothiazolinone is 1: (60-80).

3. The bactericidal composition for controlling bacterial wilt according to claim 2, wherein the mass ratio of fluazinam to benziothiazolinone is 1: (70-80).

4. The bactericide for preventing and treating bacterial wilt is characterized in that the effective components are fluazinam and a synergistic bactericide, wherein the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (55-80) or 4: 1.

5. The fungicide for controlling bacterial wilt according to claim 4, wherein the mass ratio of fluazinam to benziothiazolinone is 1: (60-80).

6. The fungicide for controlling bacterial wilt according to claim 5, wherein the mass ratio of fluazinam to benziothiazolinone is 1: (70-80).

7. The bactericide for controlling bacterial wilt according to any one of claims 4 to 6, wherein the bactericide is water-dispersible granules, wettable powder, a suspending agent, emulsifiable concentrate, an aqueous emulsion or a microemulsion.

8. The application of the bactericide in the aspect of preventing and treating plant bacterial wilt is characterized in that the active ingredients of the bactericide are fluazinam and a synergistic bactericide, and the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (4-80) or 4: 1.

9. The use according to claim 8, wherein the mass ratio of fluazinam to benziothiazolinone is 1: (55-80).

10. The use of claim 8 or 9, wherein the plant bacterial wilt disease is tobacco bacterial wilt disease.

Technical Field

The invention belongs to the field of sterilization compositions, and particularly relates to a sterilization composition for preventing and treating bacterial wilt, a bactericide and application.

Background

Bacterial Wilt of plants (Bacterial wild) is a devastating soil-borne vascular bundle disease caused by Ralstonia solanacearum, with a wide distribution of pathogenic bacteria that can infect hundreds of crops in more than 50 families, such as tobacco, tomato, potato, etc. (Middleton and Hayward, 1990, sio et al, 2012). Ralstonia solanacearum is infected from the root or wound of a plant, invades xylem vascular bundles and quickly enters the overground part of the plant through the vascular system, and particularly serious harm is caused to solanaceae crops. Tobacco is an important economic crop in China, the speed of tobacco bacterial wilt running and spreading is accelerated along with the continuous cropping age of tobacco fields in recent years, the disease rate of serious fields reaches 100%, and the tobacco bacterial wilt running and spreading is one of the main diseases of tobacco production.

The ralstonia solanacearum has higher genetic variability and environmental adaptability, has complex bacterial systems, is seriously harmful and difficult to prevent and treat, is an important limiting factor in tobacco production, and effective prevention and treatment measures of the ralstonia solanacearum are always key and difficult points in production. At present, the control of bacterial wilt in production mainly adopts comprehensive measures of combining agricultural control, biological control and chemical control. Because different control methods have limitations or restrictions and bacterial wilt is often mixed with fungal and oomycete diseases, no effective measure is provided for controlling bacterial wilt.

The chemical agents play irreplaceable important roles in the prevention and treatment of the diseases by virtue of the characteristics of high efficiency and quick acting, but the currently registered agents for the prevention and treatment of the bacterial wilt only comprise 8 non-high-efficiency agents except biocontrol bacteria, wherein the agents mainly comprise zhongshengmycin, thiediazole copper, chloropicrin, thienconcopper, chlorourea, copper sulfate, trichloroisocyanuric acid, metalaxyl, hymexazol and metalaxyl, thiram and thiram, and the varieties of the agents are very limited (Chinese pesticide information network, Zhang Hao, 2018).

The application publication number of CN107668048A discloses a compound bactericide for preventing and treating tomato gray mold, which consists of tetramycin and fluazinam in a mass ratio of 3: 1. At present, chemical agents with excellent control effects on bacterial wilt are still lacking.

Disclosure of Invention

The invention aims to provide a bactericidal composition for preventing and treating bacterial wilt, which can effectively prevent and treat bacterial wilt.

The second purpose of the invention is to provide a bactericide for controlling bacterial wilt.

The third purpose of the invention is to provide the application of the bactericide in the aspect of preventing and controlling bacterial wilt of plants.

In order to achieve the purpose, the technical scheme of the bactericidal composition for preventing and treating bacterial wilt of the invention is as follows:

a bactericidal composition for preventing and treating bacterial wilt comprises fluazinam and a synergistic bactericide, wherein the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (55-80) or 4: 1.

Fluazinam is a protective bactericide (Anema et al, 1992) developed by Japan stone Prov. corporation, is a representative medicament in pyridinamine compounds, is high-efficiency and low-toxicity, has a wide control spectrum, is registered as a pesticide in China in 2008, and has good bacteriostatic activity and control effect on most phytopathogens and mites of phytopathogens such as phytophthora parasitica, plasmodiophora and anophomycetes and sexless fungi (Matheron and Porchs, 2000, Donald et al, 2001, the Muwenjun et al, 2018).

Since the fluazinam was put into production in the last 80 th century, no field strain which can generate resistance to fluazinam alone is found, and the existing research shows that the drug resistance of plant pathogenic fungi to fluazinam develops slowly. Fluazinam has no interactive resistance with bactericides with other action mechanisms, and can be used for treating the existing resistance risk (Korolev et al, 2011, Ziogas et al, 2006, Kalamarakis et al, 2000). The registered targets of fluazinam in China are pepper phytophthora blight, potato late blight and Chinese cabbage clubroot, the target control, the use frequency and the control area of fluazinam are gradually increased year by year in China and the world in recent years, but the fluazinam mainly takes fungi and oomycetes and is not applied to the control of bacterial diseases.

The fluazinam has oxidative phosphorylation uncoupling activity, and has synergistic effect in the aspect of bacterial wilt prevention and control when being compounded with the benziothiazolinone according to a certain proportion.

Preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (60-80). More preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (70-80).

The technical scheme of the bactericide for preventing and treating bacterial wilt of the invention is as follows:

a bactericide for preventing and treating bacterial wilt comprises active ingredients (active ingredients) of fluazinam and a synergistic bactericide, wherein the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (55-80) or 4: 1.

The bactericide has good control effect on the tobacco bacterial wilt, provides technical support for the efficient use of pesticide reduction, and is beneficial to realizing the scientific control of the tobacco bacterial wilt disease.

Preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (60-80). More preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (70-80).

On the basis of the above active ingredients, a formulation acceptable for agricultural chemicals can be prepared according to a technique known in the art. Preferably, the bactericide is water dispersible granules, wettable powder, suspending agent, missible oil, aqueous emulsion or microemulsion.

The bactericide is applied to the prevention and treatment of plant bacterial wilt, the active ingredients of the bactericide are fluazinam and a synergistic bactericide, and the synergistic bactericide is benziothiazolinone; the mass ratio of fluazinam to benziothiazolinone is 1: (4-80) or 4: 1.

Preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (55-80).

Preferably, the mass ratio of fluazinam to benziothiazolinone is 1: (10-80), 1: (20-80), 1: (30-80), 1: (40-80), 1: (50-80), 1: (55-80), 1: (60-80) or 1: (70-80).

Experiments prove that the bactericide has a synergistic control effect on tobacco bacterial wilt caused by ralstonia solanacearum, and is beneficial to reduction and efficient use of pesticides.

On the basis of the bactericidal composition, the bactericidal composition can be prepared into any preparation formulation suitable for agriculture by adopting a conventional method, such as wettable powder, suspending agent, water dispersible granules, missible oil, emulsion in water, microemulsion and the like. The bactericidal composition in the preparation is an effective component, and the mass content of the bactericidal composition can be 0.5-90% of the total mass of the preparation.

In the above formulation, in addition to the above fungicidal composition, one or more agriculturally pharmaceutically acceptable adjuvants and other substances useful for stably exerting the drug effect of the active ingredient in the formulation, which are various ingredients commonly used or allowed to be used in the formulation of agricultural chemicals, are generally used. The auxiliary agent comprises wetting dispersant, stabilizer, antifreeze, disintegrant, thickener, defoamer, organic solvent, carrier and the like, and the specific selection and dosage of the auxiliary agent can be determined by routine tests according to the formula requirements. Alternative varieties of adjuvants are exemplified below. Specifically, the method comprises the following steps:

the wetting dispersant can be selected from one or more of sodium dodecyl sulfate, calcium lignosulfonate, alkylphenol polyoxyethylene formaldehyde condensate, polyoxyethylene lauryl sulfate sodium, nekal, polyoxyethylene lauryl phosphate, hydroxymethyl cellulose and the like.

The stabilizer can be one or more of citric acid, epoxidized soybean oil, sodium sorbate, butyl glycidyl ether, phenyl glycidyl ether, dinaphthol, mononaphthol and the like.

The antifreeze can be any one of glycerol, propylene glycol, ethylene glycol, urea, sodium chloride and the like.

The disintegrating agent can be selected from one or more of ammonium sulfate, calcium chloride, bentonite, ammonium dihydrogen phosphate, etc.

The thickener can be one or more selected from xanthan gum, arabic gum, soluble starch, sucrose, glucose, sodium alginate, acrylic polymer, soybean protein, dextrin, silicic acid, magnesium aluminum silicate, etc.

The defoaming agent can be any one of silicone oil defoaming agent, silicone defoaming agent and the like.

The organic solvent may be selected from one or more of isopropanol, butanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerol, sorbitol, benzyl alcohol, vegetable oil, etc.

The carrier can be selected from one or more of diatomite, talc, bentonite, kaolin, white carbon black, calcite, attapulgite and the like.

Detailed Description

The following examples are provided to further illustrate the practice of the invention. In the following examples, fluazinam (98% active ingredient), purchased from Shanghai assist, trade, Inc. Nano copper solution, nano silver solution and nano sulfur solution, the concentration is10³mu.g/mL, all available from New nanocrystal materials, Wisco.

The dimethyl sulfoxide for fluazinam is configured into 10⁵mu.g/mL of the mother liquor was stored at 4 ℃.

The kasugamycin is prepared with sterilized water with the concentration of 10⁴mu.g/mL of the mother liquor. Thiomycinone is prepared with dimethyl sulfoxide to 10⁵mu.g/mL of the mother liquor.

In the following examples, fluazinam solutions, kasugamycin solutions, and benziothiazolinone solutions of different concentrations were prepared from mother liquors and corresponding solvents. The solvent used for preparing the kasugamycin solution is sterilized water. The solvent used for preparing the fluazinam solution and the benziothiazolinone solution is dimethyl sulfoxide.

First, specific examples of the fungicide for controlling bacterial wilt of the invention

Example 1

The bactericide for preventing and treating bacterial wilt in the embodiment is prepared by compounding a fluazinam solution with the concentration of 5 mug/mL and a kasugamycin solution with the concentration of 5 mug/mL according to the volume ratio of 1: 80.

The solution density of the fluazinam solution and the kasugamycin solution can be calculated according to 1g/ml, and after the mass conversion, the mass ratio of the fluazinam to the kasugamycin is 1: 80.

Example 2

The bactericide for preventing and treating bacterial wilt in the embodiment is prepared by compounding fluazinam solution with the concentration of 0.14 mug/mL and benziothiazolinone solution with the concentration of 0.14 mug/mL according to the volume ratio of 4: 1.

On the basis of the embodiment, the concentration of the fluazinam solution and the concentration of the benziothiazolinone solution are controlled to be the same, and are respectively 0.1, 0.18, 0.2, 0.25, 0.3, 0.35, 0.5, 1 and 5 mu g/mL, and the mixture is compounded according to the volume ratio of 4:1 to form the corresponding bactericide.

Example 3

The bactericide for controlling bacterial wilt in the embodiment is only different from the bactericide in the embodiment 2 in that the fluazinam solution and the benziothiazolinone solution are compounded according to the volume ratio of 1: 4.

Example 4

The bactericide for controlling bacterial wilt in the embodiment is different from the bactericide in the embodiment 2 only in that the fluazinam solution and the benziothiazolinone solution are compounded according to the volume ratio of 1: 20.

Example 5

The bactericide for controlling bacterial wilt in the embodiment is only different from the bactericide in the embodiment 2 in that the fluazinam solution and the benziothiazolinone solution are compounded according to the volume ratio of 1: 40.

Example 6

The bactericide for controlling bacterial wilt in the embodiment is only different from the bactericide in the embodiment 2 in that the fluazinam solution and the benziothiazolinone solution are compounded according to the volume ratio of 1: 80.

Example 7

The bactericide for preventing and treating bacterial wilt in the embodiment is prepared from the following raw materials: the composition comprises 1g of fluazinam, 80g of kasugamycin, 2g of sodium dodecyl sulfate, 2g of calcium lignosulfonate, 5g of cane sugar and 10g of diatomite.

The raw materials are accurately taken according to the quality and are uniformly mixed to obtain the wettable powder.

Example 8

The bactericide for preventing and treating bacterial wilt in the embodiment is prepared from the following raw materials: 8g of fluazinam, 2g of benziothiazolinone, 10g of sodium lignosulfonate, 10g of sodium dibutylnaphthalenesulfonate, 15g of sodium dodecylbenzenesulfonate, 10g of polyvinylpyrrolidone, 10g of starch, 5g of sucrose and 30g of diatomite.

Accurately taking the raw materials according to the mass, uniformly mixing, carrying out ultramicro airflow pulverization, and granulating to obtain the water dispersible granules.

Second, specific examples of the fungicidal composition for controlling bacterial wilt according to the present invention

Example 9

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and kasugamycin in a mass ratio of 1: 80.

Example 10

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and benziothiazolinone in a mass ratio of 4: 1.

Example 11

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and benziothiazolinone in a mass ratio of 1: 4.

Example 12

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and benziothiazolinone in a mass ratio of 1: 20.

Example 13

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and benziothiazolinone in a mass ratio of 1: 40.

Example 14

The bactericidal composition for controlling bacterial wilt in the embodiment consists of fluazinam and benziothiazolinone in a mass ratio of 1: 80.

Thirdly, the application of the bactericide for preventing and treating bacterial wilt is shown in the experimental example part.

Fourth, example of experiment

And (3) determining the drug sensitivity of the ralstonia solanacearum to fluazinam by adopting a growth curve determinator.

Taking fluazinam as an example, a single colony is picked from a well-grown ralstonia solanacearum streak plate and added into an NA liquid culture medium for shake culture for 19h for later use. Adding fluazinam solutions with different concentrations into an NA liquid culture medium according to a volume ratio of 1:100 (so that the concentration of fluazinam in a final system meets requirements, such as 0, 0.14, 0.18, 0.25, 0.35 and 0.5 mu g/ml respectively; wherein "0" is NA culture medium containing only dimethyl sulfoxide as control.

Adding 3 μ L of liquid medicine with different concentrations, 250 μ L of nutrient broth and 50 μ L of bacterial liquid of Ralstonia solanacearum into each well of the sample adding plate, and repeating for 3 times. The sample adding plate is placed into a growth curve tester, and the OD value is measured at the temperature of 28-30 ℃ every 30 min. The formula for calculating the growth inhibition rate of the medicament to ralstonia solanacearum is as follows: inhibition rate (OD)_{Blank control}-OD_{Drug treatment})/OD_{Blank control}X 100%. Taking logarithm of the concentration of the medicament as an x axis and a probability value of the inhibition rate as a y axis, calculating a toxicity regression curve equation y as ax + b and a correlation coefficient r thereof according to a linear relation between the logarithm of the concentration of the medicament and the probability value of the inhibition rate, and calculating the effective inhibition medium concentration EC of the medicament on pathogenic bacteria₅₀。

On the basis of single-dose toxicity measurement, fluazinam is respectively mixed with nano sulfur, nano copper, nano silver, kasugamycin and benziothiazolinone according to the volume ratio of 80: 1. 40: 1. 20: 1. the inhibition rate of the compound medicament on the ralstonia solanacearum is determined by 9 mixture ratios of 4:1, 1:4, 1:20, 1:40 and 1:80, and the final concentration of the compound medicament is shown in table 1.

TABLE 1 Final concentration of the combination

Medicament	Compounding ratio	Concentration (μ g/ml)
			Fluazinam and nano sulfur compound	80：1、40：1、20：1、4:1	0、0.12、0.16、0.2、0.4、0.8
Fluazinam and nano sulfur compound	1:1、1:4、1:20、1:40、1:80	0、0.5、2、4、8、16、40
			Fluazinam and nano-copper compounding	80：1、40：1、20：1、4:1、1:1	0、0.14、0.18、0.25、0.35、0.5
Fluazinam and nano-copper compounding	1:4、1:20、1:40、1:80	0、0.2、0.5、1、5、10
			Fluazinam and nano silver compounding	80：1、40：1、20：1、4:1、1:1	0、0.14、0.18、0.25、0.35、0.5
Fluazinam and nano silver compounding	1:4、1:20、1:40、1:80	0、0.2、0.5、1、5、10
			Fluazinam and kasugamycin compound	80：1、40：1、20：1、4:1、1:1	0，0.14，0.18，0.25，0.35，0.5
Fluazinam and kasugamycin compound	1:4、1:20、1:40、1:80	0，0.2，0.5，1，5，10
			Fluazinam and benziothiazolinone compound	80：1、40：1、20：1、4:1、1:1	0，0.14，0.18，0.25，0.35，0.5
Fluazinam and benziothiazolinone compound	1:4、1:20、1:40、1:80	0，0.1，0.2，0.3，0.5，1，5

In table 1, when the fluazinam and the nano sulfur are compounded according to a compounding ratio of 80:1, six levels of 0, 0.12, 0.16, 0.2, 0.4 and 0.8 are respectively tested, and a fluazinam solution with a concentration of 0.12 μ g/ml and a nano sulfur solution with a concentration of 0.12 μ g/ml are compounded according to a volume ratio of 80:1 by taking the concentration of 0.12 μ g/ml as an example. The fluazinam solution is prepared from fluazinam mother liquor (10)⁵μg/mL) and dimethyl sulfoxide. The nano sulfur solution is prepared from a commercial concentration nano sulfur solution (10)³μ g/mL) and sterilized water. The kasugamycin solution is prepared from kasugamycin mother liquor (10)⁴Mu g/mL) and sterilized water. The benziothiazolinone solution is prepared from benziothiazolinone mother liquor (10)⁵Mu g/mL) and dimethyl sulfoxide.

The combined action evaluation is carried out on the compound preparation by adopting a Wadley method, and the evaluation formula is as follows:

the theory of the mixture effectively inhibits the medium concentration EC₅₀(th)＝(a+b)/[a/EC(A)₅₀+b/EC(B)₅₀]

In the formula: a. b is the compounding proportion of fluazinam and nano pesticide (or kasugamycin and benziothiazolinone) respectively,%; EC (A)₅₀Is the effective inhibiting middle concentration of fluazinam, mu g/mL; EC (B)₅₀The concentration is the effective inhibition medium concentration of the nano pesticide, namely mu g/mL.

Coefficient of synergy SR ═ EC₅₀(th)/EC₅₀(ob)

In the formula: EC (EC)₅₀(th) is the theoretical effective inhibition median concentration of the mixture, μ g/mL; EC (EC)₅₀(ob) is the observed effective inhibitory median concentration of the combination, μ g/mL.

SR is less than or equal to 0.5, which shows that the combination of the two medicaments has antagonistic action; when SR is 0.5-1.5, the two agents are compounded to have an additive effect; SR is more than or equal to 1.5, which shows that the combination of the two medicaments has synergistic effect.

(1) Joint toxicity of fluazinam and nano sulfur compound on ralstonia solanacearum

Respectively measuring the toxicity of fluazinam (0, 0.14, 0.16, 0.18, 0.2, 0.25 and 1 mu g/ml), nano sulfur solution single agent (0, 2, 4, 40, 60 and 80 mu g/ml) and fluazinam and nano sulfur compounded according to different proportions on ralstonia solanacearum, and the results are shown in table 2.

TABLE 2 Joint toxicity of fluazinam and nano sulfur combination on Ralstonia solanacearum

As can be seen from Table 2, 9 compounding ratios of fluazinam and nano sulfur have an inhibiting effect on Ralstonia solanacearum, and EC₅₀The value distribution is 0.2812-6.0406 mu g/mL, and is greater than the EC of the single fluazinam agent₅₀EC value of 0.2073 mug/mL, but less than nano sulfur single dose₅₀The value was 17.3998. mu.g/mL. EC with increasing nano-sulfur ratio₅₀The value increases and the sensitivity of the agent decreases.

According to the inhibition rate of the single agent and the compound agent on the ralstonia solanacearum, the joint toxicity effect of the fluazinam and the nano sulfur compound is evaluated by a Wadley method. As can be seen from Table 2, most of the formulation ratios have additive effects; when the fluazinam and the nano sulfur are compounded according to the volume ratio of 1:1, the fluazinam and the nano sulfur have antagonistic action, the synergistic coefficient is 0.2706, and the compounding ratio is avoided when the fluazinam and the nano sulfur are applied; when the fluazinam and the nano sulfur are compounded according to the volume ratio of 1:40, the synergistic coefficient is maximum and is 1.5955, which shows that the compounded fluazinam and the nano sulfur have synergistic effect under the volume ratio.

(2) Joint toxicity of fluazinam and nano-copper compounded on ralstonia solanacearum

Respectively measuring the toxicity of fluazinam (0, 0.14, 0.18, 0.25, 0.35 and 0.5 mu g/ml), nano-copper solution single agent (0, 1, 2.5, 5, 10 and 30 mu g/ml) and fluazinam and nano-copper compounded according to different proportions on ralstonia solanacearum, and the results are shown in Table 3.

TABLE 3 Joint toxicity of fluazinam and nano-copper compounding on Ralstonia solanacearum

As can be seen from Table 3, fluazinam and nano-copper are compounded according to 9 proportions, and EC of different bactericide compositions on ralstonia solanacearum₅₀The value distribution range is 0.1422-7.2033 mu g/mL, and the values are all less than the EC of the nano-copper single agent on ralstonia solanacearum₅₀The value was 21.4797. mu.g/mL. When fluazinamWhen the fluazinam/nano copper composite material is compounded with nano copper according to the volume ratio of 1:1 to 1:4, the synergistic coefficient of the composite material is less than 0.5, which shows that the compounding of fluazinam and nano copper shows antagonism under the condition of the volume ratio; and the other 7 compounding proportions have the synergistic coefficient of the fluazinam and the nano copper of 0.7214-1.1867, which shows that the fluazinam and the nano copper have additive effect.

(3) Joint toxicity of fluazinam and nano-silver compounded on ralstonia solanacearum

Respectively measuring the toxicity of fluazinam (0, 0.14, 0.18, 0.25, 0.35 and 0.5 mu g/ml), nano-silver solution single agent (0, 1, 2.5, 5, 10 and 30 mu g/ml) and fluazinam and nano-silver compounded according to different proportions on ralstonia solanacearum, and the results are shown in Table 4.

TABLE 4 Joint toxicity of fluazinam and nano-silver compounded on Ralstonia solanacearum

As can be seen from Table 4, fluazinam and nano-silver have inhibition effects on ralstonia solanacearum under different compounding ratios, and the mixture of 9 compounding bactericides has EC on ralstonia solanacearum₅₀The value distribution range is 0.3873-9.4596 mu g/mL, and the values are all less than the EC of the nano-silver single agent on ralstonia solanacearum₅₀The value of 15.4204 mu g/mL is larger than the EC of fluazinam single dose on ralstonia solanacearum₅₀The value is obtained.

Evaluating the joint toxicity of the fluazinam and the nano-silver by a Wadley method, wherein the fluazinam and the nano-silver show antagonism when the fluazinam and the nano-silver are compounded according to the ratio of 20:1, 4:1, 1:1 and 1: 4; when the fluazinam and the nano silver are compounded according to the ratio of 80:1, 40:1, 1:20, 1:40 and 1:80, the fluazinam and the nano silver have additive effects, and when the fluazinam and the nano silver are compounded according to the ratio of 1:20, the coefficient of synergy is 1.4067.

(4) Combined toxicity of fluazinam and kasugamycin compound on ralstonia solanacearum

The toxicity of the bactericide composition prepared by compounding fluazinam with kasugamycin in different proportions, and fluazinam single dose (0, 0.14, 0.18, 0.25, 0.35, 0.5. mu.g/ml), kasugamycin single dose (0, 0.5, 1, 3, 6, 20. mu.g/ml), and fluazinam and kasugamycin were respectively measured, and the results are shown in Table 5.

TABLE 5 Joint virulence of fluazinam and kasugamycin combinations against ralstonia solanacearum

As can be seen from Table 5, fluazinam and kasugamycin all have an inhibiting effect on ralstonia solanacearum under different compounding ratios, and the EC of the mixture of 9 compounding bactericides on ralstonia solanacearum₅₀The value distribution range is 0.0923-1.7244 mug/mL, the fluazinam and the kasugamycin are both additive when compounded according to the ratio of 80: 1-1: 40, and the synergistic coefficient is 1.5447 when the fluazinam and the kasugamycin are compounded according to the ratio of 1:80, so that the fluazinam and the kasugamycin have synergistic effect.

(5) Combined toxicity of fluazinam and benziothiazolinone on ralstonia solanacearum

The toxicity of the bactericidal composition prepared by compounding fluazinam single agent (0, 0.14, 0.18, 0.25, 0.35 and 0.5 mu g/ml), benziothiazolinone single agent (0, 0.3, 0.5, 0.8, 4 and 8 mu g/ml) and fluazinam and benziothiazolinone in different proportions on tobacco ralstonia solanacearum is respectively measured, and the results are shown in Table 6.

TABLE 6 Joint toxicity of fluazinam and benziothiazolinone on Ralstonia solanacearum

As can be seen from Table 6, fluazinam and benziothiazolinone have inhibition effects on ralstonia solanacearum under different compounding ratios, and the EC of 9 compound bactericide mixtures on ralstonia solanacearum₅₀The value distribution range is 0.0865-0.2784 mug/mL, the synergy is realized when the fluazinam and the benziothiazolinone are compounded according to five proportions of 4:1, 1:4, 1:20, 1:40 and 1:80, and the rest compounding proportions are respectivelyHas additive effect.

The results of the combination of fluazinam with 5 agents are summarized in table 7.

TABLE 7 optimal compounding ratio of fluazinam to 5 kinds of drugs

The ralstonia solanacearum has higher genetic variation and propagation capacity, is often mixed with other fungi and oomycete diseases, is very easy to cause disease outbreak and epidemic under the appropriate environmental conditions, and brings destructive disasters to tobacco production. The chemical control has important function in the control of tobacco bacterial wilt, the current medicament for controlling bacteria mainly takes agricultural antibiotics and copper preparations as main materials, compared with the medicament for controlling fungi, the chemical medicament with deficient bacteria-killing medicament variety, unique deep excavation action mechanism and excellent control effect is particularly important for the control and resistance control of the tobacco and other crop bacterial wilt.

The antibacterial agent provided by the invention provides more alternative agents for preventing and treating tobacco bacterial wilt. The fluazinam has acquired pesticide registration in China, and earlier researches show that the fluazinam also has a good inhibiting effect on tobacco black shank, and the compound use of the fluazinam and the benziothiazolinone can expand the control spectrum of a medicament, delay the generation of drug resistance, achieve the effect of preventing various diseases by one-time application and provide a theoretical basis for the reduction and high-efficiency use of pesticides.